Fluorescent Dye Paper-Based Method for Assessment of Pesticide Coverage on Leaves and Trees: A Citrus Grove Case Study.

Crop disease management depends on efficient and adequate pesticide distribution to reduce pest population. Instrument-based methods to evaluate the spatial distribution of pesticides are available, but they are not field-compatible because of instrument size, cost, and extensive sample preparation. The current gold standard of water-sensitive papers is field-compatible; however, these papers often produce false positives due to reaction with water from sources other than the pesticide mixture. Thus, we developed a novel method in which a fluorescent dye is sprayed over a crop with circles of filter paper (samplers) attached to the leaves. After collection, a lightbox is used to take pictures of the samplers, and an algorithm analyzes each image for percent coverage to visualize the pesticide distribution within the crop. Our method produces results quickly and inexpensively compared to current methods and can be applied to any crop to inform best pesticide application strategies.

A novel signal transduction protein: Combination of solute binding and tandem PAS-like sensor domains in one polypeptide chain.

We report the structural and biochemical characterization of a novel periplasmic ligand-binding protein, Dret_0059, from Desulfohalobium retbaense DSM 5692, an organism isolated from Lake Retba, in Senegal. The structure of the protein consists of a unique combination of a periplasmic solute binding protein (SBP) domain at the N-terminal and a tandem PAS-like sensor domain at the C-terminal region. SBP domains are found ubiquitously, and their best known function is in solute transport across membranes. PAS-like sensor domains are commonly found in signal transduction proteins. These domains are widely observed as parts of many protein architectures and complexes but have not been observed previously within the same polypeptide chain. In the structure of Dret_0059, a ketoleucine moiety is bound to the SBP, whereas a cytosine molecule is bound in the distal PAS-like domain of the tandem PAS-like domain. Differential scanning flourimetry support the binding of ligands observed in the crystal structure. There is significant interaction between the SBP and tandem PAS-like domains, and it is possible that the binding of one ligand could have an effect on the binding of the other. We uncovered three other proteins with this structural architecture in the non-redundant sequence data base, and predict that they too bind the same substrates. The genomic context of this protein did not offer any clues for its function. We did not find any biological process in which the two observed ligands are coupled. The protein Dret_0059 could be involved in either signal transduction or solute transport.

Development and evaluation of an ultrasonic personal aerosol sampler.

Assessing personal exposure to air pollution has long proven challenging due to technological limitations posed by the samplers themselves. Historically, wearable aerosol monitors have proven to be expensive, noisy, and burdensome. The objective of this work was to develop a new type of wearable monitor, an ultrasonic personal aerosol sampler (UPAS), to overcome many of the technological limitations in personal exposure assessment. The UPAS is a time-integrated monitor that features a novel micropump that is virtually silent during operation. A suite of onboard environmental sensors integrated with this pump measure and record mass airflow (0.5-3.0 L/min, accurate within 5%), temperature, pressure, relative humidity, light intensity, and acceleration. Rapid development of the UPAS was made possible through recent advances in low-cost electronics, open-source programming platforms, and additive manufacturing for rapid prototyping. Interchangeable cyclone inlets provided a close match to the EPA PM2.5 mass criterion (within 5%) for device flows at either 1.0 or 2.0 L/min. Battery life varied from 23 to 45 hours depending on sample flow rate and selected filter media. Laboratory tests of the UPAS prototype demonstrate excellent agreement with equivalent federal reference method samplers for gravimetric analysis of PM2.5 across a broad range of concentrations.

The function and evolution of male and female genitalia in Phyllophaga Harris scarab beetles (Coleoptera: Scarabaeidae).

Genitalia diversity in insects continues to fuel investigation of the function and evolution of these dynamic structures. Whereas most studies have focused on variation in male genitalia, an increasing number of studies on female genitalia have uncovered comparable diversity among females, but often at a much finer morphological scale. In this study, we analysed the function and evolution of male and female genitalia in Phyllophaga scarab beetles, a group in which both sexes exhibit genitalic diversity. To document the interaction between male and female structures during mating, we dissected flash-frozen mating pairs from three Phyllophaga species and investigated fine-scale morphology using SEM. We then reconstructed ancestral character states using a species tree inferred from mitochondrial and nuclear loci to elucidate and compare the evolutionary history of male and female genitalia. Our dissections revealed an interlocking mechanism of the female pubic process and male parameres that appears to improve the mechanical fit of the copulatory position. The comparative analyses, however, did not support coevolution of male and female structures and showed more erratic evolution of the female genitalia relative to males. By studying a group that exhibits obvious female genitalic diversity, we were able to demonstrate the relevance of female reproductive morphology in studies of male genital diversity.

Speciation is not necessarily easier in species with sexually monomorphic mating signals.

Should we have different expectations regarding the likelihood and pace of speciation by sexual selection when considering species with sexually monomorphic mating signals? Two conditions that can facilitate rapid species divergence are Felsenstein's one-allele mechanism and a genetic architecture that includes a genetic association between signal and preference loci. In sexually monomorphic species, the former can manifest in the form of mate choice based on phenotype matching. The latter can be promoted by selection acting upon genetic loci for divergent signals and preferences expressed simultaneously in each individual, rather than acting separately on signal loci in males and preference loci in females. Both sexes in the Chrysoperla carnea group of green lacewings (Insecta, Neuroptera, Chrysopidae) produce sexually monomorphic species-specific mating signals. We hybridized the two species C. agilis and C. carnea to test for evidence of these speciation-facilitating conditions. Hybrid signals were more complex than the parents and we observed a dominant influence of C. carnea. We found a dominant influence of C. agilis on preferences in the form of hybrid discrimination against C. carnea. Preferences in hybrids followed patterns predicting preference loci that determine mate choice rather than a one-allele mechanism. The genetic association between signal and preference we detected in the segregating hybrid crosses indicates that speciation in these species with sexually monomorphic mating signals can have occurred rapidly. However, we need additional evidence to determine whether such genetic associations form more readily in sexually monomorphic species compared to dimorphic species and consequently facilitate speciation.

Pseudomonas moraviensis subsp. stanleyae, a bacterial endophyte of hyperaccumulator Stanleya pinnata, is capable of efficient selenite reduction to elemental selenium under aerobic conditions.

AIMS: To identify bacteria with high selenium tolerance and reduction capacity for bioremediation of wastewater and nanoselenium particle production. METHODS AND RESULTS: A bacterial endophyte was isolated from the selenium hyperaccumulator Stanleya pinnata (Brassicaceae) growing on seleniferous soils in Colorado, USA. Based on fatty acid methyl ester analysis and multi-locus sequence analysis (MLSA) using 16S rRNA, gyrB, rpoB and rpoD genes, the isolate was identified as a subspecies of Pseudomonas moraviensis (97.3% nucleotide identity) and named P. moraviensis stanleyae. The isolate exhibited extreme tolerance to SeO3(2-) (up to 120 mmol l(-1)) and SeO4(2-) (>150 mmol l(-1)). Selenium oxyanion removal from growth medium was measured by microchip capillary electrophoresis (detection limit 95 nmol l(-1) for SeO3(2-) and 13 nmol l(-1) for SeO4(2-)). Within 48 h, P. moraviensis stanleyae aerobically reduced SeO3(2-) to red Se(0) from 10 mmol l(-1) to below the detection limit (removal rate 0.27 mmol h(-1) at 30 °C); anaerobic SeO3(2-) removal was slower. No SeO4(2-) removal was observed. Pseudomonas moraviensis stanleyae stimulated the growth of crop species Brassica juncea by 70% with no significant effect on Se accumulation. CONCLUSIONS: Pseudomonas moraviensis stanleyae can tolerate extreme levels of selenate and selenite and can deplete high levels of selenite under aerobic and anaerobic conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: Pseudomonas moraviensis subsp. stanleyae may be useful for stimulating plant growth and for the treatment of Se-laden wastewater.

Conductivity detection for monitoring mixing reactions in microfluidic devices.

A conductivity detector was coupled to poly(dimethylsiloxane)-glass capillary electrophoresis microchips to monitor microfluidic flow. Electroosmotic flow was investigated with both conductivity detection (CD) and the current monitoring method. No significant variation was observed between these methods, but CD showed a lower relative standard deviation. Gradient mixing experiments were employed to investigate the relationship between the electrolyte conductivity and the electrolyte concentration. A good linear response of conductivity to concentration was obtained for solutions whose difference in concentrations were less than 27 mM. The new system holds great promise for precision mixing in microfluidic devices using electrically driven flows.

High-throughput multi-analyte screening for renal disease using capillary electrophoresis.

End-state renal disease (ESRD) affects 300000 people in the United States each year. A large percentage of these individuals (approximately 20%) die within the first year after diagnosis. Current methods of determining renal function rely on the measurement of a single marker using slow and frequently non-specific colorimetric methods. In this report, capillary zone electrophoresis was used to perform a multi-analyte assay for markers of renal function in urine. This method tested for creatinine (Cr), creatine (Cn), uric acid (UA), and p-aminohippuric acid (PAH) levels. The limits of detection (S/N=3) were found to be 5 microM for Cr, 0.75 microM for Cn, and 1.5 microM for UA and PAH. Linear ranges were determined to be 5-500 microM for Cr, 0.75-500 microM for Cn, and 1.5-250 microM for UA and PAH. These ranges included the expected concentrations of the markers in human urine after 50-fold dilution. This screening method proved to be a simple and fast way to perform a high throughput analysis for multiple renal function indicators.

Dynamic coating using polyelectrolyte multilayers for chemical control of electroosmotic flow in capillary electrophoresis microchips.

Poly(dimethylsiloxane) (PDMS) capillary electrophoresis (CE) microchips were modified by a dynamic coating method that provided stable electroosmotic flow (EOF) with respect to pH. The separation channel was coated with a polymer bilayer consisting of a cationic layer of Polybrene (PB) and an anionic layer of dextran sulfate (DS). According to the difference in charge, PB- and PB/ DS-coated channels supported EOF in different directions; however, both methods of channel coating exhibited a pH-independent EOF in the pH range of 5-10 due to chemical control of the effective zeta-potential. The endurance of the PB-coated layer was determined to be 50 runs at pH 3.0, while PB/DS-coated chips had a stable EOF for more than 100 runs. The effect of substrate composition and chip-sealing methodology was also evaluated. All tested chips showed the same EOF on the PB/DS-coated channels, as compared to uncoated chips, which varied significantly. No significant variation for separation and electrochemical detection of dopamine and hydroquinone between coated and uncoated channels was observed.

Family stressor events, family coping, and adolescent adaptation in farm and ranch families.

Data from 77 adolescents in farm and ranch families were used to examine the relationship of demographic variables, family stressor events, and family coping strategies to adolescent adaptation. Results indicated that adolescent age and family transitions were positively related to individual stress. Males reported less family stress than did females. Seeking spiritual support was negatively related to family stress, while the perceived impact of the farm crisis was positively related to family stress. Family support was positively related, and family substance use issues were negatively related, to adolescent satisfaction with family life. The implications of these findings are discussed.

Microfabricated recessed microdisk electrodes: characterization in static and convective solutions.

Construction and characterization of microfabricated recessed microdisk electrodes (RMDs) of 14- and 55-µm diameters and 4-µm depth are reported. For evaluation of electrode function, both faradaic current in Ru(NH(3))(6)(3+)/KNO(3) solution and charging current in KNO(3) solution were measured with cyclic voltammetry. The experimental maximum current was measured and compared to calculated values, assuming radial and linear diffusion. A model for diffusion to a RMD best matches the behavior of the 14-µm RMD, which has a larger depth-to-diameter ratio than the 55-µm RMD. At fast scan rates (204 V s(-)(1)), where linear diffusion should dominate, there are large deviations from the linear diffusion model. Uncompensated resistance and overcorrection for background current contribute to this deviation. The dependence of capacitance on scan rate of the RMDs was found to be similar to that of a macroelectrode, indicating good adhesion between the insulator and the electrode. Chronoamperometry of Ru(NH(3))(6)(3+) in KNO(3) in both static and stirred solutions was performed using the RMDs and the current is compared to those from a 10-µm-diameter planar microdisk electrode (PMD). The signal-to-noise ratio of the 14-µm RMDs compared to the PMD is on average 4 times greater for stirred solutions. The 55-µm RMD exhibited no protection to convection of the stirred solution.

Life satisfaction among low-income rural youth from Appalachia.

The purpose of this study was to examine the relative strength of objective, subjective, and congruency variables as predictors of life satisfaction among low-income youth from rural areas. A 10-year longitudinal survey of low-income, rural youth from Appalachia (n = 322) was conducted to explore these issues. Although support was provided for variables representing all three types of life satisfaction predictors, the strongest of these were subjective variables such as self-perceptions about goal attainment in jobs, overall goal attainment in life, and self-esteem. Another set of consistent predictors of life satisfaction, congruence variables, were concerned with the extent to which low-income you believed that they had fulfilled their own aspirations in terms of formal education, proximity to their childhood homes, and number of children, Finally, some of the objective variables consisting of family of origin's SES, community size, and marital status also were predictive of life satisfaction. In general, the life satisfaction of low-income, rural youth seemed to be influenced more extensively by personal meanings shaped within a particular cultural context rather than by traditional objective measures of life circumstances.

Family characteristics and adolescent substance use.

Using self-report questionnaire data from high school students (N = 253), the relation between adolescents' perceptions of family characteristics and adolescent substance use patterns were examined. Results indicated that adolescents' perception of maternal substance use, family hardiness, and age of the adolescent were significant predictors of adolescent substance use. Implications are presented.

Adolescent social competence, parental qualities, and parental satisfaction.

Dimensions of adolescent social competence and parental qualities were examined as predictors of parental satisfaction using a sample of 736 parents. Several aspects of adolescent social competence and parental qualities were found to predict parental satisfaction. Of these, parental support was the strongest predictor, while the use of induction (rational control) was related only to fathers' well-being. Perceptions of adolescent social competence evidenced some differences between mothers and fathers in parental satisfaction. Implications for intervention strategies are discussed.

Validation of the Adolescent Family Life Satisfaction Index: an update.

This report replicates an earlier validation study of the Adolescent Family Life Satisfaction Index using a sample of 111 subjects ages 13 to 18 years. Reliability was supported for the over-all instrument and subscales. Principal components factoring yielded two factors representing satisfaction with the Parental and Sibling subsystems. Correlations with scores on another instrument indicated concurrent validity of the instrument.

Family system characteristics and parental behaviors as predictors of adolescent substance use.

The purpose of this study was to examine adolescent perceptions of family system characteristics and parental behaviors as predictors of adolescent substance use. Self-report questionnaire data were collected from a sample of 489 high school students. Bivariate correlations and multiple regression analysis were used to examine the research hypotheses. Results indicated that the frequency of parental substance use was positively related to adolescent substance use, while family bonding and parental support were negatively related. The results provide support for considering both family system characteristics and parenting behaviors in relation to adolescent substance use.

Singing and cryptic speciation insects.

Biologists have long known of the existence of 'inaudible' songs in insects, but recent work has shown such substrate-borne or near-field signals to be virtually ubiquitous, and often correlated with high numbers of sibling species. In a sexual context, silent singing has the formidable advantage of privacy: neither predators nor sexual competitors can listen and disrupt. Privacy enhances species recognition by promoting signal complexity. It also encourages the evolution of intricate signals in females as well as males, leading to obligatory dueting behavior during pair formation. Current evidence suggests that song divergence in dueting taxa can facilitate rapid, sympatric speciation.

Adolescent suicide and families: an ecological approach.

Suicide is an issue of increasing concern for professionals who work with adolescents and their families. Over the past three decades, the rate of suicide has increased dramatically among 15- to 24-year-olds and is the third leading cause of death in this age group. Previous theoretical approaches to understanding adolescent suicide (i.e., Durkheim's sociological theory of suicide, social learning theory, psychological theory, and family systems theory) are reviewed, and the utilization of human ecological theory is proposed. Factors associated with adolescent suicide at the organism (individual), microsystem, mesosystem, exosystem, and macrosystem levels are examined. Finally, examples of prevention and intervention at each level are presented.

Reliability and validity of the Adolescent Family Life Satisfaction Index.

The purpose of this study was to develop and evaluate the Adolescent Family Life Satisfaction Index. The self-report questionnaire was tested for internal consistency reliability. Tests for construct validity, concurrent validity, and internal consistency reliability provided support for the use of the over-all Adolescent Family Life Satisfaction Index, Parental Subscale, and Sibling Subscale for the measurement of adolescents' reports of satisfaction with family life.

The Stressors of Clergy Children Inventory: reliability and validity.

The purpose of this study was to develop and evaluate the Stressors of Clergy Children Inventory. The initial self-report survey was tested for internal consistency reliability. Tests for construct validity, concurrent validity, and internal consistency reliability indicated the inventory could be used in research. Recommendations for refinement and use were presented.