Showing papers by "University of Nebraska–Lincoln published in 1993"

Frame Disputes within the Nuclear Disarmament Movement

Abstract: Social movement organizations (SMOs) devote considerable effort to constructing particular versions of reality, developing and espousingalternativevisions, and attempting to affect various audiences' interpretations. Conflicts regarding such interpretive matters, referred to as 'frame disputes," are ubiquitous within movements. Using a multimethod strategy, this study analyzes the dynamics of interorganizationalframe disputes within the nuclear disarmament movement, including their organizational and ideological contexts, conditions conducive to theiremergence, patterns observed, and their effects. Three generic types of disputes are identified and elaborated: diagnostic, prognostic, andframe resonance disputes. Of the 51 disputes observed, all but two involved SMOs from two or more different movement factions. More disputes occurred between the movement's most moderate and radicalfactions than between otherfactions. Intramural conflicts were both detrimental andfacilitative of the disarmament movement and its SMOs. In the most extensive review to date of social movement literature, McAdam, McCarthy and Zald (1988) conclude that we know little about "the dynamics of collective action past the emergence of a movement" (728). Until recently, even less was known about grievance interpretation and communication processes, the essence of movement dynamics. Scholars have begun to address this lacuna by attending to various movement interpretive processes including public discourse (Gamson 1988; Gamson & Modigliani 1989; Steinberg 1989), frame alignment (Benford 1987; Snow & Benford 1988,1992; Snow et al. 1986), grievance interpretation and reality construction (Benford & Hunt 1992; Ferree & Miller 1985; Gusfield 1981; Klandermans 1992; Mauss 1975; Tarrow 1992; Turner & Killian 1987), and collective identity (Friedman & McAdam 1992; Gamson 1991; Hunt 1991; Hunt & Benford 1994; Melucci 1980, 1985, 1988, 1989; Pizzomo 1978; Taylor & Whittier 1992). *This is a revisedversion of apaperpresentedat the annual meetings oftheMidwestSociological Society,April6-9,1989, in St.Louis. Iamgrateful to ScottA.Hunt,MichelleHughesMiller,David A. Snow, and two anonymous reviewersfor their advice and comments on earlier drafts. Please direct correspondence to the author at the Department of Sociology, University of NebraskaLincoln, 703 OldfatherHall, Lincoln, NE 68588-0324. i) The University of North Carolina Press Social Forces, March 1993, 71(3):677-701 This content downloaded from 157.55.39.137 on Fri, 27 May 2016 05:34:23 UTC All use subject to http://about.jstor.org/terms 678 / Social Forces 71:3, March 1993 Although often empirically grounded, the bulk of these developments have been theoretical. Few analyses examine how well these concepts stand up empirically. McAdam, McCarthy and Zald (1988) suggest that "what is needed is more systematic, qualitative fieldwork into the dynamics of collective action at the intermediate meso level . . . the level at which most movement action occurs and of which we know the least" (729). With these considerations in mind, this article analyzes empirically the negotiated and often contentious nature of grievance construction and communication processes within the nuclear disarmament movement by focussing on intramovement frame disputes.

Oligonucleotides containing 5-fluorouracil

Abstract: A homo-oligonucleotide of between 2 and 26 monomers of 5-fluorouridine 5'-monophosphate or 5-fluorodeoxyuridine 5'-monophosphate covalently linked via 3'- to 5'-phosphodiester linkages, where at the 3'- or 5'- terminus there is covalently linked a molecule selected from the group consisting of cholesterol, ethyl-spaced adamatane, 1,2-di-hexadecylglycerol and poly-L-lysine. These homo-oligonucleotides exhibit antitumor activity.

A Content Analysis of Environmental Advertising Claims: A Matrix Method Approach

Abstract: As organizations seek to communicate with consumers who are concerned about the environment, advertisements containing environmental claims are becoming more prominent. While much has been written about environmental advertising, this phenomenon has seldom been examined systematically. This paper presents an empirical study which combines two classification schemes to create a matrix that identifies different types of environmental claims and the likelihood that such claims will be judged as misleading and/or deceptive. Results suggest that those claims which extol the environmental benefits of products and those that are designed to enhance the environmental image of an organization are most prone to be considered misleading and/or deceptive. Methods for improving environmental advertising are suggested.

Non-Hodgkin's Lymphomas

Abstract: Part 1 Lymphomagenesis: Lymphocyte differentiation Adult T-cell leukaemia/Lymphoma - a model of retrovirus-induced lymphomagenesis Burkitt's lymphoma and Epstein-Barr virus-associated lymphoid malignancies - models for lymphomagenesis T(14 18) translocation. Part 2 Methods: Histological and immunohistochemical methods Genotype. Part 3 Nodal Non-Hodgkin's Lymphomas: The normal lymph node - structure and function Histological classification Staging of NHLs Analytical study of the different subtypes of NHLs - clinical, histological and immunohistochemical aspects NHLs in childhood NHLs associated with HIV infection. Part 4 Extra-Nodal Non-Hodgkin's lymphomas: Malignant lymphomas of mucosa-associated lymphoid tissues Primary gastrointestinal NHLs Pathology of gastro-intestinal NHLs Cutaneous lymphomas NHLs of the Mediastinum NHLs of the lung Bone marrow involvement Blood involvement in chronic (mature) B & T lymphoproliferative syndromes Liver involvement Spleen involvement Extra-cranial head-and-neck NHLs Central nervous system involvement NHLs of bone Urogenital localizations. Part 5 Treatment of Non-Hodgkin's Lymphomas: Methodology and problems in the comparison of results Treatment of lowgrade NHLs The role of radiation therapy Treatment of aggressive lymphomas (intermediate and highgrade) Intensive chemoradiotherapy and bone-marrow transplantation Salvage therapy after failure Treatment of NHLs in childhood.

Family preservation using multisystemic treatment: Long-term follow-up to a clinical trial with serious juvenile offenders

Abstract: In a randomized clinical trial, multisystemic family preservation was shown to significantly reduce rates of criminal activity and incarceration in a sample of 84 serious juvenile offenders and their multi-need families. In the current study, archival records were searched for re-arrest an average of 2.4 years post-referral. Survival analysis showed that youths who received multisystemic family preservation were less likely to be re-arrested than were youths who had received usual services. Such results represent the first controlled demonstration that family preservation, when delivered via a clearly specified treatment model, has lasting effects with serious juvenile offenders. Implications for family preservation and juvenile justice research are discussed.

Advertising and social comparison: Consequences for female preadolescents and adolescents

Abstract: The authors investigate the impact of advertising beauty images on female preadolescents and adolescents An experiment using 4th, 8th, and 12th graders demonstrated that exposure to advertising with highly attractive models raises comparison standards for physical attractiveness, but does not affect self-perceptions of physical attractiveness The findings also suggest that the tendency of female pre-adolescents and adolescents to compare themselves to models in ads increases with age, and this tendency is greater for those with lower self-perceptions of physical attractiveness and/or self-esteem © 1993 John Wiley & Sons, Inc

“You Could be the Hundredth Monkey”: Collective Action Frames and Vocabularies of Motive Within the Nuclear Disarmament Movement

Abstract: Building on recent developments by social constructionists, this paper seeks to advance theoretical and empirical understanding of micromobilization processes associated with social movement recruitment and participation. Data derived from a fouryear field study of the nuclear disarmament movement are employed to identify and elaborate four generic vocabularies of motive that emerge via interaction among activists, rank and file supporters, recruits and significant others: vocabularies of (1) severity, (2) urgency, (3) efficacy and (4) propriety. These vocabularies of motive provide movement actors with compelling rationales to take action on behalf of the movement and/or its organizations. The data suggest that peace movement groups cultivate the imputation and avowal of these motives as a means of stimulating collective action. Several implications for future research are offered which draw upon the insights of resource mobilization theory and social constructionism.

The use of NOAA AVHRR data for assessment of the urban heat island effect

Abstract: The objective of the study was to evaluate the use of a satellite-derived vegetation index and surface temperature estimates for the assessment of the difference in urban and rural air temperature due to the urban heat island effect. The difference in the ND (normalized difference) index between urban and rural regions appears to be an indicator of the difference in surface properties (evaporation and heat storage capacity) between the two environments that are responsible for the urban heat island effect. The use of the approach proposed here may provide a globally consistent method for assessing this phenomenon.

Permeability and Mechanical Properties of Cellulose-Based Edible Films

Abstract: Factors affecting barrier properties [oxygen permeability (OP) and water vapor permeability (WVP)] and mechanical properties [tensile strength (TS) and elongation (E)] were investigated for methyl ccllulose (MC) and hydroxypropyl cellulose (HPC) films. OP, WVP and TS of MC and HPC films increased as the molecular weight (MW) of the cellulose increased. E of MC films increased as MW increased, but E of HPC films was highest for the intermediate MW of 370,000. OP, WVP and TS of MC films were not a function of thickness, but E slowly increased as film thickness increased. OP and WVP of HPC films were not relatable to film thickness, but TS and E of HPC films slowly increased as film thickness increased. TS decreased and E increased for both film types as concentration of plasticizers was increased. Plasticizers enhanced or retarded OP and WVP of cellulosebased films, depending on their concentrations.

Edible films and coatings from soy protein

Abstract: A method was developed by which films could be prepared from commercial isolated soy protein (ISP). ISP was treated with alkali (ATISP) to alter film orooerties. Water vapor oermeability (WVP). oxygen‘permeability (O2P), tensile strength (TS), percent elongatidn (%E), and appearance of ISP and ATISP were compared. Alkali treatment had no effect on WVP. O2P, and TS, gave hieher %E, and improved film appearance. Films properties were also compared at pH 6, 8, 10, and 12. In general, pH 6 gave higher WVP and O2P and lower TS and %E; while higher pH gave lower WVP and O2P and higher TS and %E. ATISP films could not be produced at pH 6. Film appearance generally improved with increased pH.

Arabidopsis GLABROUS1 Gene Requires Downstream Sequences for Function.

Abstract: The Arabidopsis GLABROUS1 (GL1) gene is a myb gene homolog required for the initiation of trichome development. In situ hybridization revealed that the highest levels of GL1 transcripts were present in developing trichomes. In contrast, previous work had shown that putative promoter sequences from the 5[prime] noncoding region of the GL1 gene directed the expression of a [beta]-glucuronidase (GUS) reporter gene only in stipules. Deletion analysis of the 3[prime] noncoding region of GL1 has identified an enhancer that is essential for GL1 function. Sequences from the region containing the enhancer, in conjunction with GL1 upstream sequences, direct the expression of a GUS reporter gene in leaf primordia and developing trichomes in addition to stipules, indicating that the downstream enhancer is required for the normal expression pattern of GL1.

Paper 2. agricultural impacts of and responses to climate change in the Missouri-Iowa-Nebraska-Kansas (MINK) region

Abstract: The climate of the 1930s was used as an analog of the climate that might occur in Missouri, Iowa, Nebraska and Kansas (the MINK region) as a consequence of global warming. The analog climate was imposed on the agriculture of the region under technological and economic conditions prevailing in 1984/87 and again under a scenario of conditions that might prevail in 2030. The EPIC model of Williamset al. (1984), modified to allow consideration of the yield enhancing effects of CO2 enrichment, was used to evaluate the impacts of the analog climate on the productivity and water use of some 50 representative farm enterprises. Before farm level adjustments and adaptations to the changed climate, and absent CO2 enrichment (from 350 to 450 ppm), production of corn, sorghum and soybeans was depressed by the analog climate in about the same percent under both current and 2030 conditions. Production of dryland wheat was unaffected. Irrigated wheat production actually increased. Farm level adjustments using low-cost currently available technologies, combined with CO2 enrichment, eliminated about 80% of the negative impact of the analog climate on 1984/87 baseline crop production. The same farm level adjustments, plus new technologies developed in response to the analog climate, when combined with CO2 enrichment, converted the negative impact on 2030 crop production to a small increase. The analog climate would have little direct effect on animal production in MINK. The effect, if any, would be by way of the impact on production of feed-grains and soybeans. Since this impact would be small after on-farm adjustments and CO2 enrichment, animal production in MINK would be little affected by the analog climate.

Feeding value of wet distillers byproducts for finishing ruminants.

Abstract: Yearling and calf finishing trials (replicated over 2 yr) evaluated the feeding value of wet distillers byproducts (wet distillers grains and thin stillage). An additional trial estimated the amount of thin stillage bypassing the rumen when consumed by drinking. Yearlings were 5, 10, and 20% more efficient (linear, P < .01; quadratic, P = .05), whereas calves were 2, 6, and 14% more efficient (linear, P < .01) when fed 5.2, 12.6, and 40.0% (DM basis) wet distillers byproducts, respectively, compared with cattle fed a 79% dry-rolled corn diet. Cattle fed 5.2 or 12.6% wet distillers byproducts, or the dry-rolled corn diet, received similar amounts of protein (crude or metabolizable), which exceeded the metabolizable protein requirement of all cattle. Therefore, differences in efficiency were attributed to differences in energy utilization of the diets. Wet distillers byproducts fed at 5.2, 12.6 and 40.0% contributed 80, 62, and 47% more net energy for gain than corn when fed to yearlings and 17, 33, and 29% more net energy for gain than corn when fed to calves, respectively. Wet distillers byproducts averaged 169% the energy value of corn (2.53 Mcal of NEg/kg) when fed to yearlings and 128% the energy value of corn (1.96 Mcal of NEg/kg) when fed to calves. The increased energy values cannot be explained by increased digestibility, but they may be due to a combination of factors (reduced acidosis, increased energy utilization, yeast end products, etc.) that increase the net energy content of distillers byproducts. Approximately 50% of the thin stillage consumed by drinking bypassed ruminal fermentation.(ABSTRACT TRUNCATED AT 250 WORDS)

Root Development and Nitrogen Influx of Corn Genotypes Grown under Combined Drought and Nitrogen Stresses

Abstract: Knowledge about the interactive effects of N and drought stresses on corn (Zea mays L.) root morphology and rate of N uptake is important for selecting drought tolerant and/or N efficient genotypes and for determining mechanisms that control root growth under stress. The objective was to study these interactions by growing three and four genotypes of known N utilization efficiency (NUE, kg grain/kg N uptake) responses in greenhouse and field experiments, respectively. Nitrogen application rates were 0, 30, 60, and 90 mg N kg −1 soil in the greenhouse and 0, 60, 120, and 180 kg N ha −1 in the field experiment. Water regimes included nonstress vs. an 8-d water stress in the greenhouse experiment and dryland vs. irrigation in the field []

Estimates of variances due to direct and maternal effects for growth traits of Romanov sheep.

Abstract: Records of growth traits of 2,086 Romanov lambs were used to estimate variance components for an animal model and genetic correlations between growth traits. Traits analyzed were birth weight (BWT), weaning weight (WW), 90-d weight (W90), and daily gain for the periods birth to weaning (DG1) and weaning to 90 d (DG2). Weaning was at approximately 40 d. Variance components were estimated using restricted maximum likelihood with an animal model including fixed effects for year x season, sex, rearing type, and litter size and random effects for the direct genetic effect of the animal (with relative variance h2), the maternal genetic effect (with relative variance m2), the permanent environmental effect (with relative variance c2), and random residual effect. Genetic correlations were estimated for a model with the same fixed effects and only additive genetic effects. Estimates of the variances of random effects, h2, m2, and c2, respectively, as a proportion of phenotypic variance were .04, .22, .10 (BWT); .34, .25, .0 (WW); .09, .01, .07 (W90); .26, .17, .02 (DG1); and .15, .01, .03 (DG2). Estimates of genetic correlations were .12 (BWT with WW); .24 (BWT with W90); .48 (WW with W90); .69 (DG1 with DG2); -.01 (BWT with DG1); .05 (BWT with DG2); .59 (WW with DG1); .47 (WW with DG2); .67 (W90 with DG1); and .98 (W90 with DG2). Results suggest that selection should be effective for WW, DG1, and DG2 but less effective for BWT and W90. An important maternal effect was observed for BWT, WW, and DG1. The estimates of genetic correlations showed no genetic antagonisms among the traits.

Managing Russian Factory Workers: The Impact of U.S.–Based Behavioral and Participative Techniques

Abstract: A within-subjects experimental design was used to study the impacts that 3 popular and successful techniques used in US studies had on the performance of workers in the largest textile factory in Russia. The results demonstrate both the potential benefits and problems of transporting US-based human resource management theories and techniques to other cultures. The finding confirmed 2 hyphotheses, which predict that extrinsic rewards and behavioral management interventions will have a positive impact on the performance of Russian textile workers. However, 2 other hypotheses, which predict that a participative intervention will not result in improved performance, was also confirmed. The participative intervention seemed to have a counterproductive effect on the Russian workers' performance. The failure of the participative approach, however, does not mean that this approach will not work across cultures. Historical and cultural values and norms should be recognized and overcome for such a technique to work effectively.

Temperature Effect on Oxygen Permeability of Edible Protein-based Films

Abstract: Edible films from corn zein, wheat gluten, and wheat gluten/soy protein isolate (2.1:0.9) were produced and their oxygen permeabilities were determined at 7, 15, 25, and 35°C under 0% relative humidity. Mean oxygen permeability values for the 3 films were in the range of 1.8–11.2, 0.9–6.1, and 0.6–3.8 amol/m.s.Pa, respectively. Data for all 3 films showed very good agreement with the Arrhenius activation energy model. No structural transitions were indicated within these films in this temperature range. Calculated activation energy values for the oxygen permeation process were 11.1, 11.9, and 10.8 kcal/mol, respectively. Comparisons with some non-protein edible coatings and plastic packaging materials showed dry protein films were very efficient oxygen barriers.

PsaE Is Required for in Vivo Cyclic Electron Flow around Photosystem I in the Cyanobacterium Synechococcus sp. PCC 7002

Abstract: Electron transfer rates to P700+ have been determined in wild-type and three interposon mutants (psaE-, ndhF-, and psaE- ndhF-) of Synechococcus sp. PCC 7002. All three mutants grew significantly more slowly than wild type at low light intensities, and each failed to grow photoheterotrophically in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) and a metabolizable carbon source. The kinetics of P700+ reduction were similar in the wild-type and mutant whole cells in the absence of DCMU. In the presence of DCMU, the P700+ reduction rate in the psaE mutant was significantly slower than in the wild type. In the presence of DCMU and potassium cyanide, added to inhibit the outflow of electrons through cytochrome oxidase, P700+ reduction rates increased for both the psaE- and ndhF- strains. The reduction rates for these two mutants were nonetheless slower than that observed for the wild-type strain. The further addition of methyl viologen caused the rate of P700+ reduction in the wild type to become as slow as that for the psaE mutant in the absence of methyl viologen. Given the ability of methyl viologen to intercept electrons from the acceptor side of photosystem I, this response reveals a lesion in cyclic electron flow in the psaE mutant. In the presence of DCMU, the rate of P700+ reduction in the psaE ndhF double mutant was very slow and nearly identical with that for the wild-type strain in the presence of 2,4-dibromo-3-methyl-6-isopropyl-p-benzoquinone, a condition under which physiological electron donation to P700+ should be completely inhibited. These results suggest that NdhF- and PsaE-dependent electron donation to P700+ occurs only via plastoquinone and/or cytochrome b6/f and indicate that there are three major electron sources for P700+ reduction in this cyanobacterium. We conclude that, although PsaE is not required for linear electron flow to NADP+, it is an essential component in the cyclic electron transport pathway around photosystem I.

The use of a vegetation index for assessment of the urban heat island effect

Abstract: A vegetation index and radiative surface temperature were derived from NOAA-11 Advanced Very High Resolution Radiometer (AVHRR) data for the Seattle, WA region from 28 June through 4 July 1991. The vegetation index and surface temperature values were computed for locations of weather observation stations within the region and compared to observed minimum air temperatures. These comparisons were used to evaluate the use of AVHRR data to assess the influence of the urban environment on observed minimum air temperatures (the urban heat island effect). AVHRR derived normalized difference vegetation index (NDVI) and radiant surface temperature data from a one week composite product were both related significantly to observed minimum temperatures, however, the vegetation index accounted for a greater amount of the spatial variation observed in mean minimum temperatures. The difference in the NDVI between urban and rural regions appears to be an indicator of the difference in surface properties (i.e., evaporation and heat storage capacity) between the two environments that are responsible for differences in urban and rural minimum temperatures.

On the semantics of theory change: arbitration between old and new information

Abstract: Katsuno and Mendelzon divide theory change, the problem of adding new information to a logical theory, into two types: revision and update. We propose a third type of theory change: arbitration. The key idea is the following: the new information is considered neither better nor worse than the old information represented by the logical theory. The new information is simply one voice against a set of others already incorporated into the logical theory. From this follows that arbitration should be commutative. First we define arbitration by a set of postulates and then describe a model-theoretic characterization of arbitration for the case of propositional logical theories. We also study weighted arbitration where different models of a theory can have different weights.

Syntactic segmentation and labeling of digitized pages from technical journals

Abstract: A method for extracting alternating horizontal and vertical projection profiles are from nested sub-blocks of scanned page images of technical documents is discussed. The thresholded profile strings are parsed using the compiler utilities Lex and Yacc. The significant document components are demarcated and identified by the recursive application of block grammars. Backtracking for error recovery and branch and bound for maximum-area labeling are implemented with Unix Shell programs. Results of the segmentation and labeling process are stored in a labeled x-y tree. It is shown that families of technical documents that share the same layout conventions can be readily analyzed. Results from experiments in which more than 20 types of document entities were identified in sample pages from two journals are presented. >

Differential allocation of resources underlies the dispersal-reproduction trade-off in the wing-dimorphic cricket, Gryllus rubens

Abstract: The cricket, Gryllus rubens (Orthoptera, Gryllidae), exists in natural populations as either a fully-winged (LW), flight-capable morph or as a short-winged (SW) morph that cannot fly. The SW morph is substantially more fecund than the LW morph. In this study we report on the physiological basis of this trade-off between flight capability and fecundity. Results from gravimetric feeding trials indicate that LW and SW morphs are equivalent in their consumption and digestion of food. However, during the adult stage, the LW morph is less efficient in converting assimilated nutrients into biomass. This may be a consequence of the respired loss of assimilated nutrients due to the maintenance of functional flight muscles in the LW morph. In both morphs the gross biomass devoted to flight muscles does not change significantly during the first 14 days of adult growth while there is a significant biomass gain in ovarian tissue mass during the same period. SW morphs have vestigial flight muscles and gain substantially more ovarian mass relative to the LW morphs. These data are consistent with a trade-off between flight muscle maintenance in the LW morph and ovarian growth in the SW form. This is the first evidence for a life-history trade-off that has a physiological basis which is limited to the allocation of acquired and assimilated nutrients within the organism.

Influence of ruminal protozoa on site and extent of starch digestion and ruminal fermentation.

Abstract: Eight ruminally, duodenally, and ileally fistulated sheep were used to study the effects of protozoa on ruminal fermentation and starch digestion in the rumen and intestines. The experimental diet (75% grain DM basis) was based on a mixture of 67% high-moisture corn (HMC) and 33% dry-rolled grain sorghum (DRGS). Protozoa were reduced from 51,286 to 13,987 organisms/mL of ruminal fluid by feeding a diet (13 d) containing 9% tallow and monensin at 27 mg/kg (DM basis). Three sheep were defaunated by intraruminal infusions of lactic acid (20 to 30 g/d) and one sheep by washing the rumen and heating ruminal contents (60 degrees C for 20 min). No differences were observed in DM or starch intake, ruminal fluid pH, lactate concentration, or total tract starch digestibility. Molar proportion of acetate was reduced (48.6 vs 58.3%; P < .01) and propionate was increased (32.2 vs 23.4%; P < .03) by defaunation. Total VFA tended (P = .20) to be lower in faunated sheep (118.5 vs 139.2 mM). In situ rate of starch digestion of HMC (22.3 vs 14.7 %/h; P < .02) and DRGS (5.1 vs 3.3 %/h; P < .009) was increased by defaunation. Starch digestibility (percentage of intake) in the rumen was increased (P < .001) by defaunation (84.2 vs 93.7%) and was reduced (P < .002) in the small intestine (5.2 vs 13.6%). Defaunation increased (P < .03) amylolytic activity (.40 vs .17 units/mg of protein; P < .03) and osmotic pressure (321 vs 245 mOsm/kg; P < .006).(ABSTRACT TRUNCATED AT 250 WORDS)

Separation of chiral phases in monolayer crystals of racemic amphiphiles

Abstract: OPTICAL activity manifested by chiral molecules and crystals is of long-standing interest in physics, chemistry, biology and geology1,2. The structure of chiral lattices in two and three dimensions may provide insights into chiral discrimination, and chiral phases play an important part in the physics and applications of liquid-crystal and amphiphilic films3–7. Here we report the observation of spontaneous separation of chiral phases in an oriented monolayer of rigid, chiral amphiphiles deposited on mica. Atomic force microscopy of the ordered films reveals domains of mirror-image structures. We propose that this may be the signature of separation into domains of pure enantiomers, although other possibilities exist. This separation of chiral phases in two dimensions may be considered analogous to the spontaneous resolution of enantiomers in three-dimensional crystallization, as exploited by Pasteur in 1848 to isolate enantiomers of sodium tartrate1.

Osteoblast attachment monitored with a quartz crystal microbalance

Abstract: A quartz crystal microbalance is used in aqueous solutions to monitor the rate of attachment of osteoblasts, bone-forming cells, to the surface of the crystal. Changes in resonant frequency of the crystal are measured for various surface coverages by osteoblasts. Crystal surface coverages are determined by digital image processing of scanning electron micrographs. A linear relationship is established between the surface coverages and the changes in resonant frequency of the crystal. The osteoblasts are observed to behave viscoelastically. Hence, the Sauerbrey equation can not be used to describe the relationship between the change in mass of osteoblasts on the surface and the change in resonant frequency of the crystal. Apparent viscosities at 5.0 MHz are also determined for osteoblasts.