bluuebunny/crossref_metadata_2025 huggingface dataset:
Functions of emulsifiers in food systems
Authors: Krog N.
Published: April 2008

Abstract and Summary

The function of food grade emulsifiers in various food products (emulsions, starch based food, yeast raised bakery products, etc.) are reviewed. The stability of emulsions against coalescence of dispersed droplets is among other factors dependent on monoor multimolecular interfacial films with viscoelastic properties formed by adsorbed emulsifier molecules. Agglomeration of fat globules in whippable emulsion is needed to obtain desired foam stability and texture and can be controlled by lipophilic emulsifiers. Complex formation with starch components (amylose) is influenced both by the chemical structure of an emulsifier and by its physical behaviour in water. Interaction with proteins takes place primarily with anionic emulsifiers or very hydrophilic, nonionic types, which thereby improves the rheological properties of wheat gluten. Emulsifiers are also used as crystal modifying agents in fats where polymorphic changes during storage creates texture problems.
Composition of milk fat globules with increased linoleic acid
Authors: Smith Lloyd M. , Bianco Douglas H. , Dunkley Walter L.
Published: April 2008

Abstract and Summary

Comparisons were made of the composition and distribution of the lipids in fat globules from conventional milks and polyunsaturated milks produced by cows fed protected lipid supplement. Washed creams were prepared from the milks of three individual cows fed a conventional ration, and three fed a protected sunflower‐soybean supplement rich in linoleic acid. The washed creams were fractionated by treatment with sodium deoxycholate and centrifugation. Each washed cream and four fractions (designated as outer globule membrane, inner membrane, pellet, and globule core) were analyzed for protein, lipid, phospholipid, cholesterol, tocopherols, carotenoids, and fatty acid composition. The outer and inner membrane fractions were further fractionated into neutral and polar (phospholipid) lipid classes by thin layer chromatography. For both types of washed cream the approximate weight distribution of total solids was: outer membrane, 1%; inner membrane, 2%; pellet, 0.1%; and core, 96%. The percentages of protein, phospholipid, cholesterol, and carotenoids were all lower in the polyunsaturated than in the conventional creams. In the polyunsaturated creams, the percentages of both saturated and unsaturated C18 acids were higher, and of acids of C16 and shorter chain length lower, than in the conventional creams. The phospholipids in the outer and inner membranes from the polyunsaturated milks had larger proportions of linoleic acid than did the phospholipids from the conventional milks. However, this increase in unsaturation was less than that of the core neutral lipids. Pancreatic lipase hydrolysis of the core fractions showed that the increased linoleic acid was introduced preferentially at the 2‐position of the triglycerides. In general, the observed changes in physical properties and in susceptibility of polyunsaturated milk to the development of oxidized flavor are consistent with the differences in the relative proportions of the various classes of lipids in the conventional and polyunsaturated milks.
Aflatoxin in corn
Authors: Shotwell O. L.
Published: April 2008

Abstract and Summary

Low incidence and levels of aflatoxin were identified in corn of all grades grown in the Midwest in 1964, 1965, and 1967. Later surveys indicate that corn grown in southern regions is subject to invasion byAspergillus flavus and subsequent aflatoxin formation. This mycotoxin is formed either in the field or in storage. In the field, such factors as insect damage and weather conditions probably influence aflatoxin formation. In storage, temperatures must be above 25 C and moisture levels above 16% if toxin is to form. Aflatoxin formed in a hot spot in stored corn in the Midwest when temperatures rose early in the summer and when the grain became wet because of leaks in the storage building. Analytical methods to detect and determine aflatoxin fall into three categories: presumptive tests indicating the presence ofA. flavus and the possible occurrence of aflatoxin, rapid screening tests establishing the presence or absence of the toxin, and quantitative procedures determining toxin levels. Detoxification methods being studied include ammoniation and roasting. Ammoniated corn is being fed domestic animals to determine whether it has adverse effects and whether toxic compounds are transmitted in animal tissues.
Relationship of physical appearance of individual mold‐damaged cottonseed to aflatoxin content
Authors: Cucullu Alva F. , Lee Louise S. , Pons W. A.
Published: April 2008

Abstract and Summary

Over 700 individual aflatoxin‐suspect cottonseed were hand‐selected from a heterogenous stockpile of ginned seed. The seed were categorized on the basis of (a) bright greenish‐yellow, fluorescence termed cateye, on the linter fibers under ultraviolet light; (b) partially bald seed with part of the linter fibers removed by ginning; (c) a combination of cateye and balding; (d) thin and discolored lint; and (e) bluish, not cateye, fluorescence. Aflatoxin assays on each of the 771 selected seed showed that 142 out of 771 (18%) were contaminated by aflatoxin (B1+B2) in the range of 150 ppb—5.75 million ppb. Some 93% of the aflatoxin‐contaminated seed was concentrated in categories (a), (b), and (c), with the highest concentration, 61%, in category (b). Eight seed in these three categories contained over 1 million ppb of aflatoxins. The data suggest that removal of cateye and partially bald seed from contaminated lots of cottonseed should be more effective for controlling aflatoxin contamination in cottonseed than removal of cateye seed alone.
Separation of aflatoxin‐contaminated cottonseed based on physical characteristics of seed cotton and ginned seed
Authors: Lee Louise S. , Cucullu Alva F. , Pons W. A. , Russell T. E.
Published: April 2008

Abstract and Summary

Samples of aflatoxin‐contaminated stored ginned cottonseed and of freshly harvested seed cotton and companion ginned seed were examined under long wave ultraviolet (UV) and visible light to develop physical criteria for separating aflatoxin‐contaminated seed from sound seed. Seed locks characterized by bright greenish‐yellow, or cateye, fluorescence when viewed under long wave UV light were separated from samples of 12 varieties of freshly harvested seed. As a result, 80–100% (mean 96%) of the aflatoxin contamination that was concentrated in 2–9% (mean 6%) of the seed weight was effectively removed. The cateye fluorescence separation technique was slightly less effective for removing aflatoxins from companion freshly harvested, ginned samples, but most of the aflatoxins were concentrated in only 0.5–3% (mean 2%) of the seed weight. This approach was relatively ineffective for stored ginned seed, probably due to deterioration of the cateye fluorescence.
Solvent extraction of aflatoxins from contaminated agricultural products
Authors: Rayner E. T. , Koltun S. P. , Dollear F. G.
Published: April 2008

Abstract and Summary

Solvent extraction of agricultural products has been suggested as an effective means of removing aflatoxins from mold‐damaged commodities. The use of various polar solvents such as the azeotrope of acetone‐hexane‐water and of 2‐propanol‐water, aqueous acetone, and aqueous ethanol has been reported in the literature. This paper examines the overall aspects of solvent extraction, in particular the use of the azeotrope of 2‐propanol‐water, to remove aflatoxins from prepress solvent extracted cottonseed meal.
Processing edible peanut protein concentrates and isolates to inactivate aflatoxins
Authors: Rhee K. C. , Natarajan K. R. , Cater C. M. , Mattil K. F.
Published: April 2008

Abstract and Summary

Experiments were conducted to study the efficacy of some oxidizing or other reactive chemicals for destruction of aflatoxins in conjunction with the aqueous extraction process for the production of peanut protein concentrates and/or isolates directly from contaminated raw peanuts. The chemicals tested included acetone, isopropyl alcohol, methylamine, hydrogen peroxide, benzoyl peroxide, ammonia gas, and sodium hypochlorite. Among these chemicals, hydrogen peroxide, benzoyl peroxide, and sodium hypochlorite showed very effective destruction of aflatoxins during the aqueous extraction process of infected peanuts. However, the use of benzoyl peroxide may pose some difficulties because it is not readily soluble in the aqueous suspensions. It was therefore concluded that aflatoxins can be effectively destroyed during the aqueous processing of peanuts by properly utilizing either sodium hypochlorite or hydrogen peroxide to produce either peanut protein concentrates or isolates.
Job Characteristics and the Labor Force Participation Behavior of Black and White Male Youth
Authors: Williams Donald R.
Published: April 2008

Previous work regarding the labor force participation of black and white youth has ignored the fact that they may face jobs with different characteristics, such as socioeconomic status or degree of danger. This article examines the effects that such characteristics have on the probability of participation for a sample of black and white males from the National Longitudinal Survey Youth Cohort. The results suggest that some job characteristics have a significant impact on participation, particularly socioeconomic status. The estimates presented here suggest, however, that racial differences in socioeconomic status probably explain only a small portion of the black-white male youth participation rate differential.
The Changing Nature of Minority Business: A Comparative Analysis of Asian, Nonminority, and Black-Owned Businesses
Authors: Bates Timothy
Published: April 2008

This study compares the performance of small businesses formed between 1976 and 1982 by three groups: 1) Asian males, 2) black males, and 3) nonminority males. Self-employed Asians are outperforming nonminorities and blacks. A subset of black-owned firms—small scale ghetto-oriented operations—is shown to be laggard. Weak internal markets, commercial bank redlining, and loss of entrepreneurial talent are factors in undermining the inner city black business community. Successful black-owned firms are increasingly removed from the ghetto and from serving a minority clientele.
The Impact of Demand Management Policies on Black Vs. White Employment
Authors: Abell John D.
Published: April 2008

This article uses vector autoregression analysis to examine the relative impacts on black and white employment growth of monetary and fiscal actions. It was found that the employment responses to anticipated policy actions, while significant, were generally short-lived, with the exception of the effects of anticipated money growth on white employment. The influences of unanticipated policy changes are of a longer duration. The predominant finding in which black employment growth responded differently from white employment growth was in response to a monetary shock. The black employment response was sharply negative while the white employment response was a gradual increase over nine quarters. The results indicate that this difference occurred only during the 1980s and not in the 1970s and suggests that the effects of bank failures and credit rationing during this period may have significantly hurt minority employment opportunities.
A Measurement of Economic Growth for Selected Caribbean Nations
Authors: Nissan Edward
Published: April 2008

This article explores economic growth performance of various Caribbean countries over a twenty-year period. Aspects of growth or decline of agricultural, industrial and service sectors are examined. In particular, the article seeks to provide an assessment of the impact of the agricultural sector on economic growth as measured by Simon Kuznets’ models and propositions in relation to agricultural product and labor contribution. General comparisons between the Caribbean countries and a sample of economies are provided. A central finding is that economic growth was minor during the period under consideration.
The Relative Quality of Black Economists
Authors: Medoff Marshall H.
Published: April 2008

This paper identifies the top black economists and ranks them in terms of their quality. The measure used as the indicator of quality is the number of citations received by an individual economist. It is argued that citations represent influence in that they reflect the degree to which others have found that work to be useful in their research and are an indication of the amount of recognition an economist's research has received. Using citation tabulations as the measure of quality, the rankings of the top twenty economists were calculated.
Nea Presidential Address, 1993: Why Black Economists?
Authors: Conrad Cecilia A.
Published: April 2008

This article looks, with humor, at the role of black economists in academia and in the economics profession.
The Cost of Government Deposits for Black-Owned Commercial Banks
Authors: Price Gregory N.
Published: April 2008

This article utilizes a Statistical Cost Accounting Model and Mean Variance Model to estimate the cost and potential risk impact of government deposits for black-owned commercial banks. The main findings are that relative to other types of deposits on the balance sheet, government deposits are expensive, and that deposits received through the Minority Bank Deposit Program may have the effect of increasing risk in the asset portfolio.
Measuring Employment Discrimination through Controlled Experiments
Authors: Bendick Marc , Jackson Charles W. , Reinoso Victor A.
Published: April 2008

Race/ethnic discrimination in hiring can be measured under controlled conditions using matched pairs of minority and nonminority research assistants posing as applicants for the same job. In 149 in-person job applications in the Washington, D.C., labor market, African American applicants were treated less favorably than equally qualified nonminorities more than one-fifth of the time. Employer behavior during these interactions suggest that, within continued public and private efforts against discrimination, particular attention should be accorded to the cognitive underpinnings of bias.
Sectoral Labor Employment in a Caribbean Economy: The Case of Barbados
Authors: Coppin Addington
Published: April 2008

This study examines the demand for labor in five major sectors of the Caribbean economy of Barbados. While the demand for labor function in the nontradable sectors appears well-defined in terms of real wages and real aggregate output, the inclusion of a variable to capture the effects of capital-deepening appears important to the specification of labor demand in the tradable sectors—agriculture and manufacturing. Low estimates of real wage elasticities and real output elasticities in the vicinity of unity suggest that employers in the major sectors are more likely to alter their demand for labor based on expectations of the economy's performance than in response to labor cost factors denominated in producer prices.
Black-White Housing Price Differentials: Recent Trends and Implications
Authors: Reifel John W.
Published: April 2008

Black-white housing price differentials consistent with racially discriminatory practices are rarely found by the studies that have used post-1970 data. Instead, those studies report price differentials consistent with the theory that whites buy segregation by bidding up the price of housing in certain neighborhoods. Unfortunately, the specifications used in most of these studies have been flawed. Here, a properly specified model is estimated using Annual Housing Survey data, augmented with objective measures of neighborhood conditions, from Grand Rapids, Michigan. The price differentials found support the trend found by the improperly specified models. Specifically, various owner bundles cost up to 16 percent more and various renter bundles cost up to 20 percent more in the predominantly white than in the predominantly black submarket. To the extent that residential integration remains one of society's goals, this trend calls for innovative policies that go beyond enforcement of existing Fair Housing laws.
An Analysis of the Repayment Patterns of Some Black Mortgagors
Authors: Williams Roger C.
Published: April 2008

While several previous studies have analyzed the intrarace differences in repayment patterns among white mortgagors, few have analyzed whether such differences occur among blacks. Much of the previous literature provides only aggregated information about black mortgagors. This research is offered as a step in filling this gap in the literature. The results indicate that there are systematic differences in repayment patterns among black mortgagors related primarily to occupation and household composition.
Utilization of Minority Employees in Small Business: A Comparison of Nonminority and Black-Owned Urban Enterprises
Authors: Bates Timothy
Published: April 2008

Structural changes in the urban economy are causing African-American workers in blue collar occupations to rely increasingly upon the small business sector for employment. This study finds that most of the nonminority-owned small businesses operating in large urban areas do not employ minorities. Even among the businesses physically located within minority communities, the majority of the workers in the nonminority small firms are white. Black-owned businesses, in contrast, rely largely on minority workers even when their firms are located outside of minority neighborhoods.
Changes in weight and weight-related quality of life in a multicentre, randomized trial of aripiprazole versus standard of care
Authors: Kolotkin Ronette L. , Corey-Lisle Patricia K. , Crosby Ross D. , Kan Hong J. , McQuade Robert D.
Published: April 2008

Background

This is a secondary analysis of clinical trial data collected in 12 European countries. We examined changes in weight and weight-related quality of life among community patients with schizophrenia treated with aripiprazole (ARI) versus standard of care (SOC), consisting of other marketed atypical antipsychotics (olanzapine, quetiapine, and risperidone).

Method

Five-hundred and fifty-five patients whose clinical symptoms were not optimally controlled and/or experienced tolerability problems with current medication were randomized to ARI (10–30 mg/day) or SOC. Weight and weight-related quality of life (using the IWQOL-Lite) were assessed at baseline, and weeks 8, 18 and 26. Random regression analysis across all time points using all available data was used to compare groups on changes in weight and IWQOL-Lite. Meaningful change from baseline was also assessed.

Results

Participants were 59.7% male, with a mean age of 38.5 years (SD 10.9) and mean baseline body mass index of 27.2 (SD 5.1). ARI participants lost an average of 1.7% of baseline weight in comparison to a gain of 2.1% by SOC participants (p < 0.0001) at 26 weeks. ARI participants experienced significantly greater increases in physical function, self-esteem, sexual life, and IWQOL-Lite total score. At 26 weeks, 20.7% of ARI participants experienced meaningful improvements in IWQOL-Lite score, versus 13.5% of SOC participants. A clinically meaningful change in weight was also associated with a meaningful change in quality of life (p < 0.001). A potential limitation of this study was its funding by a pharmaceutical company.

Conclusions

Compared to standard of care, patients with schizophrenia treated with aripiprazole experienced decreased weight and improved weight-related quality of life over 26 weeks. These changes were both statistically and clinically significant.
Cognitive insight and verbal memory in first episode of psychosis
Authors: Lepage Martin , Buchy Lisa , Bodnar Michael , Bertrand Marie-Claude , Joober Ridha , Malla Ashok
Published: April 2008

Beck and collaborators have proposed a distinction between clinical insight and cognitive insight and have developed a tool for the assessment of the latter, namely the Beck Cognitive Insight Scale (BCIS). The present study explored in 51 patients with a first episode of psychosis the neurocognitive correlates of cognitive insight as assessed with the BCIS. Global measures for seven domains of cognition including verbal learning and memory, visual learning and memory, working memory, speed of processing, reasoning and problem solving, attention, and social cognition were examined. Secondly, we examined whether two clinical insight measures, the Scale to assess Unawareness of Mental Disorder (SUMD) and the insight item from the Positive and Negative Symptoms Scale (PANSS), could produce similar or different patterns of association with neurocognitive functions as those identified with the BCIS. Correlational analyses revealed significant associations between the BCIS Composite Index and the verbal learning and memory. No significant associations were observed between any of the neurocognitive domains and the PANSS or SUMD clinical insight measures, despite high inter-correlations among the three insight measures. These results suggest that cognitive insight, but not clinical insight, may rely on memory processes whereby current experiences are appraised based on previous ones.
Preference of medicine and patient-reported quality of life in community-treated schizophrenic patients receiving aripiprazole vs standard of care: Results from the STAR study
Authors: Taylor David , Hanssens Linda , Loze Jean-Yves , Pans Miranda , L'Italien Gilbert , Marcus Ronald N.
Published: April 2008

Objective

To evaluate quality of life and patient preference for schizophrenia treatment in a community based study comparing the use of aripiprazole to the standard of care (SOC).

Method

This open-label, 26-week, multi-centre, randomised study compared aripiprazole with SOC (olanzapine, quetiapine or risperidone) in patients with schizophrenia (DSM-IV-TR criteria). The primary effectiveness variable was the mean total score of the Investigator Assessment Questionnaire (IAQ) at Week 26. The outcome research variables included the Preference of Medicine (POM) questionnaire, the Quality of Life Scale (QLS), and the EuroQoL-5D (EQ-5D). The results from these outcome research variables are the focus of this paper addressing quality of life and patient preference.

Results

A total of 555 patients were randomised to receive aripiprazole (n = 284) or SOC (n = 271). The OC data at Week 26, reported that more respondents rated the study medication as ‘much better’ compared with their previous medication in the aripiprazole group versus SOC for patients (59% vs 35%, P < 0.001) and caregivers (58% vs 30%, P = 0.014). The improvement in QLS total score was also significantly greater in the aripiprazole group compared with SOC – mean change from baseline in QLS total score of 16.21 vs 10.01 (P < 0.001) at Week 26 (OC data set). A greater proportion of patients (93% vs 85%; P = 0.005) in the aripiprazole group had a satisfactory response on the EQ-5D Self Care Scale; all other EQ-5D scores were similar.

Conclusion

The study findings suggest that quality of life and patient medication preference measures were better for aripiprazole than for SOC.
Effects of neonatal (+)‐methamphetamine on path integration and spatial learning in rats: effects of dose and rearing conditions
Authors: Vorhees Charles V. , Herring Nicole R. , Schaefer Tori L. , Grace Curtis E. , Skelton Matthew R. , Johnson Holly L. , Williams Michael T.
Published: April 2008

Postnatal day (P)11–20 (+)‐methamphetamine (MA) treatment impairs spatial learning and reference memory in the Morris water maze, but has marginal effects on learning in a labyrinthine maze. A subsequent experiment showed that MA treatment on P11–15, but not P16–20, is sufficient to induce Morris maze deficits. Here we tested the effects of P11–15 MA treatment under two different rearing conditions on Morris maze performance and path integration learning in the Cincinnati water maze in which distal cues were unavailable by using infrared illumination. Littermates were treated with 0, 10, 15, 20, or 25 mg/kg MA × 4/day (2 h intervals). Half the litters were reared under standard housing conditions and half under partial enrichment by adding stainless steel enclosures. All MA groups showed impaired Cincinnati water maze performance with no significant effects of rearing condition. In the Morris maze, the MA‐25 group showed impaired spatial acquisition, reversal, and small platform learning. Enrichment significantly improved Morris maze acquisition in all groups but did not interact with treatment. The male MA‐25 group was also impaired on probe trial performance after acquisition and on small platform trials. A narrow window of MA treatment (P11–15) induces impaired path integration learning irrespective of dose within the range tested but impairments in spatial learning are dependent on dose. The results demonstrate that a narrower exposure window (5 days) changes the long‐term effects of MA treatment compared to longer exposures (10 days).
Assessment of STAN S21 fetal heart monitor by medical staff
Authors: Rault Sebastien , Vayssiere Christophe , Roth Emmanuel , David Eric , Favre Romain , Langer Bruno
Published: April 2008

Objective

To compare the responses of medical staff using the STAN S21 fetal heart monitor versus standard cardiotocography (CTG) to monitor abnormal fetal heart rate in labor.

Method

Questionnaires were completed by medical staff involved in a randomized controlled trial to compare STAN surveillance with traditional surveillance before the trial had finished. Respondents were questioned about their experience and confidence using the STAN system.

Results

The response rate was 82% (89/109). Overall, 71% of respondents preferred using STAN surveillance, while 5% preferred standard CTG. Reasons given for preference over CTG alone were the continuous nature of surveillance (47%), the need for fewer scalp pH tests (39%), and its capacity to screen for severe fetal distress (30%).

Conclusion

Most of the medical staff surveyed preferred using STAN versus standard surveillance techniques to monitor abnormal fetal heart rate during labor.
Late Quaternary lake-level fluctuations in the Mababe Depression: Middle Kalahari palaeolakes and the role of Zambezi inflows
Authors: Burrough S.L. , Thomas D.S.G.
Published: April 2008

A systematic drilling and optical dating programme on Middle Kalahari beach ridge (relict shoreline) sediments has enabled the identification of multiple episodes of lake high stands of an extensive palaeolake system at the terminus of the Okavango Delta, northern Botswana. This paper presents 23 ages from the Mababe Depression and establishes four shoreline construction phases in the late Quaternary coeval with other sub-basin lake high stands (Lake Ngami). These synchronous lake phases result from a coalescence of the sub-basins into a unified palaeolake, Lake Thamalakane, covering an area of ∼ 32,000 km2. Six additional ages are also presented from the Chobe enclave to the north of the basin where shoreline ridges were emplaced at the same time as Lake Thamalakane phases. This suggests that increased flow in the Chobe and Zambezi system significantly contributed to the Middle Kalahari lake phases in both the post-glacial and Holocene periods. The integration of these new data and their compatibility with other regional and tropical palaeo-archives is discussed in the light of understanding Quaternary climate drivers within the Kalahari.
High-resolution and Precisely dated record of weathering and hydrological dynamics recorded by manganese and rare-earth elements in a stalagmite from Central China
Authors: Zhou Houyun , Chi Baoquan , Lawrence Michael , Zhao Jianxin , Yan Jun , Greig Alan , Feng Yuexing
Published: April 2008

Manganese (Mn) and rare-earth elements (REEs) in a stalagmite (SJ3) collected from Central China were analyzed, using an ICP-MS method for the precise determination of > 40 trace elements in geological samples by enriched-isotope internal standardization. Unlike speleothem Mn and REEs investigated by cathodoluminescence, which may be incorporated into crystal lattice, the Mn and REEs analyzed in SJ3 should come largely from colloidal and particle phases in groundwater and may be associated with non-carbonate inclusions. The Mn and REEs in SJ3 vary significantly during the period between 20 and 10 ka. These elements show remarkable increases since ∼ 14.5 ka, suggesting enhanced weathering of the overlying soil layer and the host rock since the onset of the last deglaciation and the strengthening of the Asian summer monsoon. In addition, the Mn and REEs in SJ3 display significant centennial fluctuations which may reflect groundwater dynamics.
On the Possibility of Real‐Time Monitoring of Glucose in Cell Culture by Microdialysis Using a Fluorescent Glucose Binding Protein Sensor
Authors: Ge Xudong , Rao Govind , Tolosa Leah
Published: April 2008

Although glucose sensors with millimolar sensitivity are still the norm, there is now a developing interest in glucose sensors with micromolar sensitivity for applications in minimally invasive sampling techniques such as fast microdialysis and extraction of interstitial fluid by iontophoresis and laser poration. In this regard, the glucose binding protein (GBP) with a binding constant for glucose in the micromolar range is of particular relevance. GBP is one of the soluble binding proteins found in the periplasmic space of Gram‐negative bacteria. Because of its hinge‐like tertiary structure, glucose binding induces a large conformational change, which can be used for glucose sensing by attaching a polarity sensitive fluorescent probe to a site on the protein that is allosterically responsive to glucose binding. Correspondingly, the resulting optical biosensor has micromolar sensitivity to glucose. Because binding is reversible, the biosensor is reusable and can be stored at 4 °C for 6 months without losing its sensitivity. In this paper, we show the feasibility of using the GBP biosensor to monitor glucose in microdialysis. The effect of perfusion rate, bulk glucose concentration and temperature on microdialysis efficiency was determined. Additionally, the glucose concentrations in mammalian cell culture were monitored to demonstrate the applicability of this sensor in complex and dynamic processes over a period of time. As the sensor is sensitive to micromolar glucose, high dialysis efficiency is not required when the bulk glucose concentration is within the millimolar physiological range. Thus, a perfusion rate of 10 μL/min or faster can be used, resulting in delay times of 1 min or less.
Identifying Inhibitory Threshold Values of Repressing Metabolites in CHO Cell Culture Using Multivariate Analysis Methods
Authors: Xing Zizhuo , Li Zhengjian , Chow Vincent , Lee Steven S.
Published: April 2008

Elevation of lactate, ammonia, osmolality, and carbon dioxide to inhibitory levels was reported to have adverse effects on cell growth and protein productivity in mammalian cell culture. Multivariate analysis methods were used to investigate the roles of these repressing metabolites in a fed‐batch CHO cell culture for antibody fusion protein B1 (B1) production. Principal Factor Analysis methodology was applied to manufacturing‐scale data of 112 cell culture runs, which identified threshold values of four repressing metabolites as follows: (1) ammonium levels above 5.1 mM inhibit cell growth; (2) both lactate and osmolality levels above 58 mM and 382 mOsm/kg affect cell viability; and (3) carbon dioxide levels at or above 111 mmHg reduce protein quality. These threshold values were then verified by simulations using Monod‐type equations and Canonical Correlation. These results suggest that adverse effects on cell growth, productivity, and product quality may be minimized under the ideal cell culture condition, in which the peak values of all four repressing metabolites are maintained below the threshold values. This strategy was evaluated in 45 cell culture runs in 50‐L bioreactors. Eight out of 45 runs were operated under the ideal condition, while the remaining 37 runs had at least one repressing metabolite with peak value at or above the threshold. In comparison to the remaining runs, the eight cell culture runs under the ideal condition had 17%, 40%, and 11% higher values in peak viable cell density, final B1 titer, and quality attribute, respectively. The unique methodology used in this study may be generally applicable in characterizing cell culture processes.
Deletion of G protein-coupled receptor 48 leads to ocular anterior segment dysgenesis (ASD) through down-regulation of Pitx2
Authors: Weng Jinsheng , Luo Jian , Cheng Xuhong , Jin Chang , Zhou Xiangtian , Qu Jia , Tu LiLi , Ai Di , Li Dali , Wang Jun , Martin James F. , Amendt Brad A. , Liu Mingyao
Published: April 2008

The development of the anterior segment of the mammalian eye is critical for normal ocular function, whereas abnormal development can cause glaucoma, a leading cause of blindness in the world. We report that orphan G protein-coupled receptor 48 (Gpr48/LGR4) plays an important role in the development of the anterior segment structure. Disruption of
Gpr48
causes a wide spectrum of anterior segment dysgenesis (ASD), including microphthalmia, iris hypoplasia, irdiocorneal angle malformation, cornea dysgenesis, and cataract. Detailed analyses reveal that defective iris myogenesis and ocular extracellular matrix homeostasis are detected at early postnatal stages of eye development, whereas ganglion cell loss, inner nuclear layer thinness, and early onset of glaucoma were detected in 6-month-old
Gpr48
−/−
mice. To determine the molecular mechanism of ASD caused by the deletion of
Gpr48
, we performed gene expression analyses and revealed dramatic down-regulation of
Pitx2
in homozygous knockout mice.
In vitro
studies with the constitutively active Gpr48 mutant receptor demonstrate that Pitx2 is a direct target of the Gpr48-mediated cAMP-CREB signaling pathway in regulating anterior segment development, suggesting a role of Gpr48 as a potential therapeutic target of ASD.
Impaired sodium excretion and increased blood pressure in mice with targeted deletion of renal epithelial insulin receptor
Authors: Tiwari Swasti , Sharma Nikhil , Gill Pritmohinder S. , Igarashi Peter , Kahn C. Ronald , Wade James B. , Ecelbarger Carolyn M. A.
Published: April 2008

Renal tubule epithelial cells express the insulin receptor (IR); however, their value has not been firmly established. We generated mice with renal epithelial cell-specific knockout of the IR by Cre-recombinase-loxP recombination using a kidney-specific (Ksp) cadherin promoter. KO mice expressed significantly lower levels of IR mRNA and protein in kidney cortex (49–56% of the WT) and medulla (32–47%) homogenates. Immunofluorescence showed the greatest relative reduction in the thick ascending limb and collecting duct cell types. Body weight, kidney weight, and food and water intakes were not different from WT littermates. However, KO mice had significantly increased basal systolic blood pressure (BP, 15 mm Hg higher) as measured by radiotelemetry. In response to a volume load by gavage (20 ml/kg of body weight, 0.9% NaCl, 15% dextrose), KO mice had impaired natriuresis (37 ± 10 versus 99 ± 9 mmol of Na
+
per 2 h in WT). Furthermore, volume load led to a sustained increase in BP in KO mice only. In contrast, insulin administration i.p. (0.5 units/kg of body weight) resulted in a significant fall in BP in WT, but not in KO mice. To test the role of reduced renal nitric oxide (NO) production in these responses, basal urinary nitrates plus nitrites excretion (UNOx) was measured and found to be 61% lower in KO vs. WT mice. Furthermore, acute insulin increased UNOx by 202% in the WT, relative to a significantly blunted rise (67%) in KO animals. These results illuminate a previously uncharacterized role for renal IR to reduce BP and facilitate sodium and water excretion, possibly via NO production.
PU.1 and C/EBPα/β convert fibroblasts into macrophage-like cells
Authors: Feng Ru , Desbordes Sabrina C. , Xie Huafeng , Tillo Ester Sanchez , Pixley Fiona , Stanley E. Richard , Graf Thomas
Published: April 2008

Earlier work has shown that the transcription factor C/EBPα induced a transdifferentiation of committed lymphoid precursors into macrophages in a process requiring endogenous PU.1. Here we have examined the effects of PU.1 and C/EBPα on fibroblasts, a cell type distantly related to blood cells and akin to myoblasts, adipocytes, osteoblasts, and chondroblasts. The combination of the two factors, as well as PU.1 and C/EBPβ, induced the up-regulation of macrophage/hematopoietic cell surface markers in a large proportion of NIH 3T3 cells. They also up-regulated these markers in mouse embryo- and adult skin-derived fibroblasts. Based on cell morphology, activation of macrophage-associated genes, and extinction of fibroblast-associated genes, cell lines containing an attenuated form of PU.1 and C/EBPα acquired a macrophage-like phenotype. The lines also display macrophage functions: They phagocytose small particles and bacteria, mount a partial inflammatory response, and exhibit strict CSF-1 dependence for growth. The myeloid conversion is primarily induced by PU.1, with C/EBPα acting as a modulator of macrophage-specific gene expression. Our data suggest that it might become possible to induce the transdifferentiation of skin-derived fibroblasts into cell types desirable for tissue regeneration.
Small-molecule RETRA suppresses mutant p53-bearing cancer cells through a p73-dependent salvage pathway
Authors: Kravchenko J. E. , Ilyinskaya G. V. , Komarov P. G. , Agapova L. S. , Kochetkov D. V. , Strom E. , Frolova E. I. , Kovriga I. , Gudkov A. V. , Feinstein E. , Chumakov P. M.
Published: April 2008

Identification of unique features of cancer cells is important for defining specific and efficient therapeutic targets. Mutant p53 is present in nearly half of all cancer cases, forming a promising target for pharmacological reactivation. In addition to being defective for the tumor-suppressor function, mutant p53 contributes to malignancy by blocking a p53 family member p73. Here, we describe a small-molecule RETRA that activates a set of p53-regulated genes and specifically suppresses mutant p53-bearing tumor cells
in vitro
and in mouse xenografts. Although the effect is strictly limited to the cells expressing mutant p53, it is abrogated by inhibition with RNAi to p73. Treatment of mutant p53-expressing cancer cells with RETRA results in a substantial increase in the expression level of p73, and a release of p73 from the blocking complex with mutant p53, which produces tumor-suppressor effects similar to the functional reactivation of p53. RETRA is active against tumor cells expressing a variety of p53 mutants and does not affect normal cells. The results validate the mutant p53–p73 complex as a promising and highly specific potential target for cancer therapy.
Arabidopsis
TAO1 is a TIR-NB-LRR protein that contributes to disease resistance induced by the
Pseudomonas syringae
effector AvrB
Authors: Eitas Timothy K. , Nimchuk Zachary L. , Dangl Jeffery L.
Published: April 2008

The type III effector protein encoded by avirulence gene B (AvrB) is delivered into plant cells by pathogenic strains of
Pseudomonas syringae
. There, it localizes to the plasma membrane and triggers immunity mediated by the
Arabidopsis
coiled-coil (CC)-nucleotide binding (NB)-leucine-rich repeat (LRR) disease resistance protein RPM1. The sequence unrelated type III effector avirulence protein encoded by avirulence gene Rpm1 (AvrRpm1) also activates RPM1. AvrB contributes to virulence after delivery from
P. syringae
in leaves of susceptible soybean plants, and AvrRpm1 does the same in
Arabidopsis rpm1
plants. Conditional overexpression of AvrB in
rpm1
plants results in leaf chlorosis. In a genetic screen for mutants that lack AvrB-dependent chlorosis in an
rpm1
background, we isolated
TAO1
(target of AvrB operation), which encodes a Toll-IL-1 receptor (TIR)-NB-LRR disease resistance protein. In
rpm1
plants, TAO1 function results in the expression of the pathogenesis-related protein 1 (PR-1) gene, suggestive of a defense response. In
RPM1
plants, TAO1 contributes to disease resistance in response to
Pto
(
P. syringae
pathovars tomato) DC3000(
avrB
), but not against
Pto
DC3000(
avrRpm1
). The
tao1–5
mutant allele, a stop mutation in the LRR domain of TAO1, posttranscriptionally suppresses RPM1 accumulation. These data provide evidence of genetically separable disease resistance responses to AvrB and AvrRpm1 in
Arabidopsis
. AvrB activates both RPM1, a CC-NB-LRR protein, and TAO1, a TIR-NB-LRR protein. These NB-LRR proteins then act additively to generate a full disease resistance response to
P. syringae
expressing this type III effector.
Improving Students' Study Habits by Demonstrating the Mnemonic Benefits of Semantic Processing
Authors: Bugg Julie M. , DeLosh Edward L. , McDaniel Mark A.
Published: April 2008

This article describes an in-class exercise that illustrates the advantage of semantic over nonsemantic study habits. The exercise includes a survey of students' current study strategies, followed by the presentation of an abbreviated version of Craik and Tulving's (1975) classic levels-of-processing experiment. We observed significant benefits of semantic processing over nonsemantic processing, and this result motivated an in-depth discussion regarding the limitations of students' intuitions about effective study strategies and methods for improving current strategies. The brief exercise changed students' intended strategies for future studying and helped students learn the concept of semantic processing.
Do Students Learn Course Material during Crib Sheet Construction?
Authors: Dickson K. Laurie , Bauer Jack J.
Published: April 2008

We experimentally investigated the effect of crib sheet construction and use on student learning and exam performance. Students expected to use their prepared crib sheets during testing; however, unexpectedly they first completed a pretest without their crib sheets. Students scored significantly better on the same questions with crib sheets compared to their performance without their sheets, signifying that constructing crib sheets did not enhance learning, but use enhanced performance. Students who expect to use crib sheets during testing rely on the sheet for information, suggesting that students do not learn the course material as well when they expect to use a crib sheet.
An Experientially and Community-Oriented Graduate Course in Clinical Geropsychology
Authors: Glenwick David S. , Fried Adam L. , Abbey Jennifer Greene
Published: April 2008

This article describes a graduate course in clinical geropsychology that combines classroom, practicum, and field-visit components. The course provides clinical and applied developmental students with an overview of the major research and clinical topics of the field, as well as firsthand exposure to the setting of the nursing home, its residents, and staff.
Teaching Traits and Constructs through Scale Construction: A Need and a Strategy
Authors: Holmes Jeffrey D.
Published: April 2008

Most students have some experience with purported measures of psychological constructs before entering college. Critical analysis of such measures requires familiarity with test development strategies. The activities outlined in this article allowed students to complete the steps involved in scale construction and empirical analysis in a relatively brief period of time. Steps included trait conceptualization, searching for literature, generating hypotheses, operationalizing constructs, collecting and analyzing data, and interpreting the quality of instruments. The activity took place in an introductory laboratory course but contains sufficient flexibility to make it useful in a variety of courses. Student evaluations of the activities were positive, and the article includes evidence of student learning.
Rate My Professor: Online Evaluations of Psychology Instructors
Authors: Silva Kathleen M. , Silva Francisco J. , Quinn Megan A. , Draper Jill N. , Cover Kimberly R. , Munoff Alison A.
Published: April 2008

We analyzed students' ratings and comments of their psychology instructors that were posted on RateMyProfessors.com and RateMyProfessors.ca to determine which features of a course and an instructor evoked the most positive and negative reactions. A content analysis of students' comments showed that instructors' characteristics (e.g., enthusiastic, organized) generated the most positive and negative comments; student development generated the fewest comments. Instructors' helpfulness and clarity were positively correlated with positive comments about their personality, teaching characteristics, and global quality. Although the psychometric qualities of the scales used on the RateMyProfessors Web sites and the representativeness of the students who made ratings on these sites are unknown, the focus of the students' comments was similar to those in studies of traditional teaching evaluations.
Does an Interactive WebCT Site Help Students Learn?
Authors: Elicker Joelle D. , O'Malley Alison L. , Williams Christine M.
Published: April 2008

We examined whether students with access to a supplemental course Web site enhanced with e-mail, discussion boards, and chat room capability reacted to it more positively than students who used a Web site with the same content but no communication features. Students used the Web sites on a voluntary basis. At the end of the semester, students using the enhanced site earned more points in the class than students using the basic Web site. Additionally, students using the enhanced site reported using it more often and reported higher satisfaction with the Web site, course, and instructor. We discuss practical implications of these findings.
Convergent Validation of an Interview-Based Personality Assessment: A Laboratory Project
Authors: Friesen Myron D. , Ellis Bruce J.
Published: April 2008

This article describes a 2-session laboratory project in which students develop, conduct, and attempt to validate an interview-based personality assessment. In Session 1, students learn about effective interview procedures and then design and pilot-test an interview to assess 4 personality traits (emotionality, activity level, sociability, and impulsivity). Each student then assesses the personality of a participant using the interview along with a self-report measure that indexes the same 4 personality traits. In Session 2, students analyze the interview and questionnaire data and examine several topics concerning measurement validation, such as convergent validity, social desirability, and error. Test grades and student evaluations supported the pedagogical value of the project.
If You Post It, Will They Come? Lecture Availability in Introductory Psychology
Authors: Hove M. Christina , Corcoran Kevin J.
Published: April 2008

Web-enhanced educational programs such as Blackboard (2003; http://www.blackboard.com/ ) provide opportunities for instructors to make supplemental course materials available to students. However, little research has investigated the effects of unlimited access to course lectures on achievement and attendance in traditional postsecondary classroom settings. Thus, we investigated the effect of lecture presentation availability on class attendance and academic performance in 2 sections of introductory psychology courses. Students with unlimited access to lecture presentations earned significantly higher grades than students who did not have similar access. Although we did not find significant differences in attendance between classes, attendance moderated the relation between class format and course grade. We discuss further implications and future research.