Radiation-induced solidification of ionic liquid under extreme electric field.

An extreme electric field on the order of 10(10) V m(-1) was applied to the free surface of an ionic liquid to cause electric-field-induced evaporation of molecular ions from the liquid. The point of ion emission was observed in situ using a TEM. The resulting electrospray emission process was observed to create nanoscale high-aspect-ratio dendritic features that were aligned with the direction of the electric field. Upon removal of the stressing field the features were seen to remain, indicating that the ionic liquid residue was solidified or gelled. Similar electrospray experiments performed in a field-emission scanning electron microscope revealed that the features are created when the high-energy electron beam damages the molecular structure of the ionic liquid. While the electric field does not play a direct role in the fluid modification, the electric stress was critical in detecting the liquid property change. It is only because the electric stress mechanically elongated the fluid during the electrospray process and these obviously non-liquid structures persisted when the field was removed that the damage was evident. This evidence of ionic liquid radiation damage may have significant bearing on electrospray devices where it is possible to produce high-energy secondary electrons through surface impacts of emitted ions downstream of the emitter. Any such impacts that are in close proximity could see reflected secondary electrons impact the emitter causing gelling of the ionic liquid.

Self-assembling array of magnetoelectrostatic jets from the surface of a superparamagnetic ionic liquid.

Electrospray is a versatile technology used, for example, to ionize biomolecules for mass spectrometry, create nanofibers and nanowires, and propel spacecraft in orbit. Traditionally, electrospray is achieved via microfabricated capillary needle electrodes that are used to create the fluid jets. Here we report on multiple parallel jetting instabilities realized through the application of simultaneous electric and magnetic fields to the surface of a superparamagnetic electrically conducting ionic liquid with no needle electrodes. The ionic liquid ferrofluid is synthesized by suspending magnetic nanoparticles in a room-temperature molten salt carrier liquid. Two ILFFs are reported: one based on ethylammonium nitrate (EAN) and the other based on EMIM-NTf2. The ILFFs display an electrical conductivity of 0.63 S/m and a relative magnetic permeability as high as 10. When coincident electric and magnetic fields are applied to these liquids, the result is a self-assembling array of emitters that are composed entirely of the colloidal fluid. An analysis of the magnetic surface stress induced on the ILFF shows that the electric field required for transition to spray can be reduced by as much as 4.5 × 10(7) V/m compared to purely electrostatic spray. Ferrofluid mode studies in nonuniform magnetic fields show that it is feasible to realize arrays with up to 16 emitters/mm(2).

Application of maximum likelihood methods to laser Thomson scattering measurements of low density plasmas.

Laser Thomson scattering (LTS) is an established plasma diagnostic technique that has seen recent application to low density plasmas. It is difficult to perform LTS measurements when the scattered signal is weak as a result of low electron number density, poor optical access to the plasma, or both. Photon counting methods are often implemented in order to perform measurements in these low signal conditions. However, photon counting measurements performed with photo-multiplier tubes are time consuming and multi-photon arrivals are incorrectly recorded. In order to overcome these shortcomings a new data analysis method based on maximum likelihood estimation was developed. The key feature of this new data processing method is the inclusion of non-arrival events in determining the scattered Thomson signal. Maximum likelihood estimation and its application to Thomson scattering at low signal levels is presented and application of the new processing method to LTS measurements performed in the plume of a 2-kW Hall-effect thruster is discussed.

Sea-change or change challenge? Health information access in developing countries: The U.S. National Library of Medicine experience.

Health professionals in developing countries want access to information to help them make changes in health care and contribute to medical research. However, they face challenges of technology limitations, lack of training, and, on the village level, culture and language. This report focuses on the U.S. National Library of Medicine experience with access: for the international medical/scientific community to health information which has been published by researchers in developing countries; for scientists and clinicians in developing countries to their own literature and to that of their colleagues around the world; for medical librarians who are a critical conduit for students, faculty, researchers, and, increasingly, the general public; and for the front line workers at the health center in the village at the end of the line. The fundamental question of whether or not information communication technology can make a difference in access and subsequently in health is illustrated by an anecdote regarding an early intervention in Africa in 1992. From that point, we examine programs to improve access involving malaria researchers, medical journal editors, librarians, and medical students working with local health center staff in the village. Although access is a reality, the positive change in health that the information technology intervention might produce often remains a mirage. Information and technology are not static elements in the equation for better access. They must function together, creating a dialectic in which they transform and inform one another and those whom their combination touches.

Resistance of cotton towards Xanthomonas campestris pv. malvacearum.

Interactions between Gossypium spp. and the bacterial pathogen Xanthomonas campestris pv. malvacearum are understood in the context of the gene-for-gene concept. Reviewed here are the genetic basis for cotton resistance, with reference to resistance genes, resistance gene analogs, and bacterial avirulence genes, together with the physiological mechanisms involved in the hypersensitive response to the pathogen, including production of signaling hormones, synthesis of antimicrobial molecules and alteration of host cell structures. This host-pathogen interaction represents the most complex resistance gene/avr gene system yet known and is one of the few in which phytoalexins are known to be specifically localized in HR cells at anti-microbial concentrations.

Descriptive sensory analysis of broiler breast fillets marinated in phosphate, salt, and acid solutions.

Sensory attributes of fully aged broiler breast fillets marinated in a 6% NaCl solution containing 2% sodium tripolyphosphate (2P), 2% citric acid (2C), 2% acetic acid (2A), 1% citric acid plus 1% phosphate solution (1C), or 1% acetic acid solution plus 1% phosphate (1A) were studied. A 6% NaCl (6S) solution with no additives was used as control. Oven-cooked samples (177C degrees oven; 75 degrees C internal temperature) were evaluated by a 9-member trained descriptive analysis sensory panel that rated the intensities of 26 different flavor and texture attributes using 15-point line scales. Data were analyzed using general linear model SAS procedures to determine significant differences (P < or = 0.05) in individual sensory attributes due to marinade treatment. All sensory attributes were scored in the low intensity range (1.5 to 5.0). Brothy, vinegar, and residual particles were the only individual attributes rated significantly different (P < or = 0.05) due to treatment. Multivariate analyses indicated that all sensory attributes formed 2 dimensions that explained 57% of variation in the data. The low intensity values for texture attributes indicated possible negative consequences due to phosphates, salt, and acids when used with fully aged fillets.

Effect of endophyte type on carcass traits, meat quality, and fatty acid composition of beef cattle grazing tall fescue.

Fourteen Hereford steers were used to compare carcass traits, meat quality, and fatty acid composition of beef from cattle grazing tall fescue infected with either wild-type (E+; n = 6) or novel, nil ergot alkaloid (AR542; n = 8) endophyte for 209 d. Average daily gain, live weight, and HCW were greater (P < 0.05) for AR542 cattle than for E+. No differences in LM color or pH were observed between AR542 and E+. Steaks from E+ cattle tended (P = 0.10) to have higher L* and b* than those from AR542 cattle at 0 d of display. Ground beef from E+ cattle also had higher (P < 0.05) L* than AR542 cattle, with no differences in a* or b* at 0 d of display. Color changes during display did not differ for both steaks and ground beef from E+ and AR542. Lipid oxidation levels increased (P < 0.05) during simulated retail display, but they did not differ between endophyte treatments. Adipose tissues from E+ cattle had a higher (P < 0.05) percentage of SFA, and a lower (P < 0.05) percentage of MUFA than adipose from AR542 cattle. Ground beef and i.m. fat had higher (P < 0.05) concentrations of SFA, MUFA, and cis-9, trans-11 isomer of conjugated linoleic acid, and lower (P < 0.05) concentrations of PUFA and PUFA:SFA ratio than s.c. fat. The n-6:n-3 fatty acid ratio did not differ among fat depots. Ergot-alkaloids were detected in s.c. adipose tissues, and alkaloid concentration was greater (P < 0.05) for E+ than AR542. Warner-Bratzler shear force values did not differ between endophyte types, but it decreased (P < 0.01) across the postmortem aging period. Conversely, sensory panel evaluation detected greater (P < 0.01) chewiness and lower (P < 0.05) juiciness for AR542 than for E+ steaks aged for 14 d. Although grazing cattle on tall fescue pastures infected with nil ergot alkaloid endophyte improved cattle performance, these results suggest that endophyte type has minor effects on carcass traits and meat quality of pasture-fed beef. Moreover, finishing cattle on tall fescue pastures showed the potential to enhance the fatty acid profile of beef from a human health perspective. Alkaloid concentration was greater (P < 0.05) in s.c. fat from E+ than AR542 (2.81 vs. 0.92 ppb; fresh-tissue basis). This is the first published report demonstrating the presence of alkaloids in beef tissues.

Prediction of physical, color, and sensory characteristics of broiler breasts by visible/near infrared reflectance spectroscopy.

The feasibility of predicting pH, color, shear force, and sensory characteristics of chicken breasts deboned at 2, 4, 6, and 24 h postmortem by visible/near infrared reflectance spectroscopy (NIRS) in the 400 to 1850 nm region was determined. Prediction of physical attributes of Commission Internationale de l'Eclairage (CIE) color values (L*, a*, and b*), pH, and shear force had better accuracies than those of individual sensory attributes. Calibration and validation statistics for shear force and sensory traits indicated that visible/near infrared models were not significantly improved for cooked muscles compared with predictions based on raw muscle characteristics. On the basis of predicted shear values from the partial least squares (PLS) model, breast samples were classified into "tender" and "tough" classes with a correct classification of 74.0% if the boundary was set at 7.5 kg. The model developed from measured shears using soft independent modeling of class analogy/principal components analysis (SIMCA/PCA) showed nearly the same classification success.

Effects of diet and feed withdrawal on the sensory descriptive and instrumental profiles of broiler breast fillets.

Effects of diet and feed withdrawal times on the sensory profile and shear values of broiler breast meat were determined. Feeds were formulated with 3 dietary carbohydrate sources (corn, milo, and wheat). Birds (n = 192) were processed between 42 and 52 d of age. Feed was withdrawn for 0 or 8 h prior to pilot plant processing under simulated commercial conditions. Pectoralis major muscles were removed 4 h postmortem and frozen until evaluated. Thawed breast fillets were cooked in heat-seal bags immersed in 85 degrees C water until an internal temperature of 80 degrees C was reached. Color, shears, and sensory profiles (18 attributes) were determined. Meat from corn-fed birds required significantly less force to shear (6.0 kg) than meat from birds fed milo (6.7 kg) or wheat (7.1 kg). Feed withdrawal did not affect the flavor profile; however, meat from birds at 0 h feed withdrawal were darker and redder. Diet significantly affected the sensory profile. Brothy scores were significantly higher in meat from corn-fed birds than in meat from birds fed wheat or milo. Diet and feed withdrawal significantly affected sensory texture. Meat from wheat-fed birds was harder, more cohesive, and more chewy and exhibited larger particle size than meat from birds fed corn or milo. Moisture release values were lower and toothpack values were higher in meat from birds processed at 0 h feed-withdrawal time compared with meat from birds held 8 h without feed. Dietary carbohydrate source appears to have a measurable impact on flavor and texture of broiler breast meat.

Principal component analysis of physical, color, and sensory characteristics of chicken breasts deboned at two, four, six, and twenty-four hours postmortem.

The effects of various postchill deboning times on functional, color, yield, and sensory attributes of broiler breast meat were determined. Broiler breast muscles were deboned at 2, 4, 6, and 24 h postmortem, and pH, color change, cooking yield, shear force values, and sensory traits of the breast meat were recorded. Data were examined by multivariate data analysis, namely principal component analysis (PCA). Averages of 13 variables (pH, delta a*, shear force, and sensory attributes of cardboardy, wet feathers, springiness, cohesiveness, hardness, moisture release, particle size, bolus size, chewiness, and metallic aftertaste-afterfeel) decreased gradually as deboning time increased from 2 to 24 h, especially for shear values after 4 h of postmortem aging. Univariate correlation coefficients among 24 variables indicated several significant correlations. Warner-Bratzler shear force had high positive correlations with 5 sensory texture attributes (cohesiveness, hardness, particle size, bolus size, and chewiness). The parameters of pH, delta L*, delta a*, delta b*, and cooking yield were not obviously correlated with shear force values or any of the 18 sensory characteristics. PCA score plot showed no clear separation of the breast muscles deboned at different postmortem times, but it was still possible to differentiate them. The loading biplot suggested that 18 variables were effective in sample differentiation, including delta L*, shear force, cooking yield, 6 sensory flavor attributes (brothy, cardboardy, wet feathers, blood/serumy, salty, and sour), all sensory texture attributes except springiness, and all afterfeel-aftertaste properties.

The effect of age, dietary carbohydrate source, and feed withdrawal on broiler breast fillet color.

An experiment was conducted to determine the effect of bird age, diet (feeds formulated with 69.5% corn, 69.7% milo, or 73.6% wheat), and feed withdrawal times (0 or 8 hours) on color (CIE L*, lightness; a*, redness; and b*, yellowness) of raw broiler breast fillets. Broilers were placed on diets at 28 d of age. Replicate groups of 24 birds (eight each from different diet and four each either full fed or feed withdrawn) were processed (slaughtered and eviscerated under simulated commercial conditions) each day from 42 to 45 and 49 to 52 d of age (n = 192). Carcasses were chilled and deboned 4 h postmortem, and triplicate color measurements taken from the medial (bone) side of the fillet. Bird age did not significantly affect fillet color values. Fillets from the birds fed the wheat diet were significantly lighter than fillets from the corn or milo fed birds (48.9 vs. 46.9 and 46.7, respectively). The milo diet resulted in significantly redder fillets than corn or wheat (3.9 vs. 3.5 and 3.3, respectively). The corn diet produced significantly more yellow fillets than milo or wheat (4.8 vs. 2.4 and 2.6, respectively). Feed withdrawal significantly increased fillet lightness from an average of 46.1 to 48.9, decreased redness from 4.1 to 3.1, and increased yellowness from 2.8 to 3.7. Raw broiler breast fillet color is significantly affected by both diet and feed withdrawal, but not by age.

Color of uncooked and cooked broiler leg quarters associated with chilling temperature and holding time.

Discoloration of raw or cooked tissue can occur from cell disruptions and blood migration caused by slow or variable chilling rates. Color parameters established by the Commission International D'Eclairage for measuring lightness, redness, and yellowness (L*, a*, and b* respectively) were determined on two groups (A and B) of uncooked and cooked leg quarters chilled at +4, 0, -3, -12, or -18 C. At Day 7, group A was evaluated for color, and group B was moved to -18 C for seven additional days and then evaluated. Group B represented cooling, freezing, thawing, and cooking steps. Color was measured on surfaces of thawed, uncooked parts (UCS), on surfaces of cooked parts (CS) 75 or 85 C internal temperature), and on cooked meat (CM) adjacent to the femur. UCS samples at -3 C were significantly redder (a* = 8.91) than -18 C samples (a* = 5.04). The A-CS a* values showed a significant interaction between chill temperature storage and internal temperature (IT). Samples at 75 C IT had higher a* values (redder). CM samples held at +4 and 0 C were significantly lighter (higher L* values). A significant interaction effect occurred for CM a* values due to storage chill temperature and IT. Generally, 75 C IT samples were redder (higher a* values). UCS and CS color was not influenced by chilling at +4 to -18 C for 7 d and then at -18 C for 7 d. CM was affected by a combination of chill temperature history and IT.

Acid phosphatase activity and color changes in consumer-style griddle-cooked ground beef patties.

The U.S. Department of Agriculture and the Food and Drug Administration have issued temperature requirements to help consumers cook beef patty products that are free of pathogens. Verification of end-point temperature (EPT) is needed in cooked meat products due to concerns over outbreaks of Escherichia coli O157:H7. Acid phosphatase (ACP) activity was studied as a potential method for determination of EPT in ground beef patties cooked nonfrozen, patties frozen 7 days and thawed at room temperature 4 h in a refrigerator or by microwave, and patties made from ground beef frozen in store packages, then thawed in a refrigerator overnight. Pressed-out meat juices were analyzed from patties (n = 314) cooked to 57.2 degrees C (135 degrees F). 65.6 degrees C (150 degrees F), 71.1 degrees C (160 degrees F), and 79.4 degrees C (175 degrees F) target EPTs. Expressed meat juice and internal meat patty color decreased in redness as EPT increased. Freezing whole packs with slow refrigerator or room temperature thawing caused significantly greater loss of redness in expressed cooked meat juice than did other handling methods. Log10 ACP had a significant linear (R2 = 0.99) response to EPT. Results show that the 3- to 5-min ACP test could be used to verify EPT in griddle-cooked hamburger patties.

Integrating theory and research into practice.

An experiential learning assignment was imPlemented in an undergraduate nursing course. The purpose of the assignment was to integrate theory and research into a nursing practice activity. The authors describe the development, implementation, and evaluation of the assignment. Evaluation data indicated that the assignment was an appropriate way to prepare beginning nursing students for building knowledge about nursing as a scholarly discipline.

Statutory and regulatory issues for clinical nurse specialist (CNS) practice: ensuring the public's access to CNS services.

The practice environment of healthcare in the United States is fluid, dynamic, and sometimes chaotic. Statutory, regulatory, and credentialing requirements are critical elements of this changeable environment affecting clinical nurse specialists (CNSs) and other advanced practice nurses (APNs). CNSs are estimated to comprise approximately 54,000 APNs, based on the 2000 National Sample Survey of Registered Nurses. Although statutes and regulations related to APNs are reviewed regularly, there has not been a critical analysis of statutes and regulations specifically governing CNS practice in the United States. This lack is largely due to the absence of a national association devoted to CNSs before 1995. However, recently there has been a resurgence of interest and need for CNS services. Therefore, it is particularly important that any statutory and/or regulatory barriers to CNS practice be removed. In 1998, the National Association of Clinical Nurse Specialists Legislative and Regulatory Committee embarked on a critical analysis of state statutes and regulations governing CNS practice. All 50 state boards of nursing and the District of Columbia board of nursing were requested to send copies of their statutes and regulations governing CNS practice. Responses were received from 48 states. This article summarizes the state of regulation of CNS practice and identifies significant barriers to CNS practice that should be systematically addressed. The patchwork quilt of CNS regulation that varies from state to state results in over-restrictive and underinclusive provisions that preclude ease of reciprocity and deprive the public full access to CNS services. Recommendations for addressing the barriers are made.

Disruptive sexual selection for plumage coloration in a passerine bird.

The theory of sexual selection was developed to explain the evolution of highly exaggerated sexual ornaments. Now supported by vast empirical evidence, sexual selection is generally considered to favour individuals with the most extreme trait expression. Here we describe disruptive selection on a sexual ornament, plumage coloration, in yearling male lazuli buntings (Passerina amoena). In habitats with limited good-quality nesting cover, the dullest and the brightest yearlings were more successful in obtaining high-quality territories, pairing with females and siring offspring, than yearlings with intermediate plumage. This pattern reflects the way that territorial adult males vary levels of aggression to influence the structure of their social neighbourhood. Adult males showed less aggression towards dull yearlings than intermediate and bright ones, permitting the dull yearlings to settle on good territories nearby. Fitness comparisons based on paternity analyses showed that both the adults and dull yearlings benefited genetically from this arrangement, revealing a rare example of sexually selected male-male cooperation.