1,347 research outputs found

    Plant tissue extraction method for complexed and free cyanide

    Get PDF
    A method for free cyanide and strongly-complexed cyanide measurement within plant tissue was developed to study uptake and movement of cyanide species separately from cyanide metabolism and metabolite movement by a willow plant (Salix eriocephala var. Michaux). Spike recoveries from solutions with and without plant tissue, using various solvent combinations, and background control tissue contributions were investigated to obtain an accurate and precise extraction method for measurement of complexed and free cyanide concentrations within plant tissue. The optimum extraction technique involved the freezing of plant tissue with liquid nitrogen to facilitate homogenization prior to extraction. Homogenized willow tissue samples, 1 to 1.5 g-fresh weight, were ground a second time under liquid nitrogen followed by grinding in slurry with 2.5 M NaOH. The slurry was brought to 100 mL volume, sonicated for 5 min, extracted in the dark for 16 h, and analyzed without filtration for total and free cyanide by acid distillation and microdiffusion respectively. Sample tissue extraction controls found recoveries of 89% and 100% for 100 µg L-1 CNT as KCN and K4Fe(CN)6 spiked in willow tissue slurries. Methanol, hexane, and 2-octanol inclusion in the solvent matrix with 2.5 M NaOH interfered with the cyanide analytical technique while chloroform reacted with NaOH and free cyanide in solution. Filtration was not included due to increased cyanide loss, and analysis of control tissue showed minimal release of cyanide or interference of plant tissue with the cyanide analytical method.Tissue cyanide concentrations from hydroponicallyexposed tissue using the optimal extraction method agreed with tissue cyanide stable isotope (15N) results

    Comparison of Aerobic Training Methods on V02 Max, Body Composition and Anaerobic Power.

    Get PDF
    Recent research has utilized intensity as a primary means to define training methods for improving aerobic capacity (VO2 max). Alternative ways of classifying training techniques must be examined to elucidate optimal practices for aerobic capacity enhancement. PURPOSE: To investigate the potential impact of various aerobic training methods on V02, body composition and anaerobic power. METHODS: Thirty-four healthy male & female subjects (18-30yrs) participated in an equated volume supervised running workout for six weeks utilizing two alternate training methods. Group one (N = 17, 21 ± 3 yr) participated in Interval Training Distance (ITD) and group two (N = 17, 21 ± 3 yr) participated in Long Slow Distance (LSD). All subjects participated in a familiarity session (FAM), a Pre-Test (T1) and a Post-Test (T2) . Each testing session consisted of a V02 Max, a 30 second Wingate and body composition assessment. Data were analyzed by a two-way ANOVA with repeated measures. Significance was set at p \u3c 0.05 and adopted throughout. RESULTS: The ITD and LSD groups experienced significant increases (p \u3c 0 .001) in VO2 max, with 9.05% (4.19 ± 4.15 ml/kg/min) and 3.18% (1.39 ± 3.67 ml/kg/min) increases respectively. A significant interaction (p \u3c 0.05) in VO2 max occurred between groups, as the ITD group displayed a 302% greater increase when compared to the LSD group. Body fat percentage significantly decreased (p \u3c 0.01) in the ITD (1.08 ± 1.90%) and LSD (1.55 ± 3.21%) groups, while a significant reduction (p \u3c 0.05) in total body weight was also observed. CONCLUSION: The findings of this study suggest that the ITD training method has a greater impact on aerobic capacity than LSD training method. However, both ITD and LSD training methods had a significant impact on aerobic capacity, body weight, and body composition

    The Effects of an Energy Increasing Supplement on Markers of V02 max, Body Composition, and Anaerobic Power

    Get PDF
    Research suggests that energy increasing supplement ingestion prior to prolonged aerobic exercise (\u3e60minutes) can improve aerobic capacity (VO2 Max). Energy increasing supplements affect on reduced aerobic training periods (\u3c60\u3eminutes) lack definitive empirical evidence. PURPOSE: To investigate the potential impact of an energy increasing supplement on aerobic training, body composition and anaerobic power. METHODS: Thirty-three healthy male and female subjects (18-30yrs) participated in an equated volume supervised running workout for six weeks utilizing long slow distance. Group one (N = 17, 21 ± 3 yr) participated in long slow distance training as a Placebo group void of any dietary instructions or interventions. Group two (N = 16, 21 ± 3 yr) participated in long slow distance training and was provided with a GU Energy Gel packet and 8 oz. of water fifteen minutes prior to the workout. All subjects participated in a familiarity session (FAM), a Pre-Test (T1) and a Post-Test (T2). Each testing session consisted of a V02 Max, a 30 second Wingate and body composition assessment. Data were analyzed by a two-way ANOVA with repeated measures. Significance was set at p \u3c 0.05 and adopted throughout. RESULTS: The GU and Placebo groups experienced significant increases (p \u3c 0.001), in VO2 max, with 9.71% (4.06 ± 2.68 ml/kg/min) and 2.81% (1.26 ± 2.25 ml/kg/min) increases respectively. A significant interaction (p \u3c 0.005) in VO2 max occurred between groups, as the GU group displayed a 322% greater increase when compared to the Placebo group. Body fat percentage significantly decreased (p \u3c 0.05) in the GU (0.76 ± 2.47%) and Placebo (1.55 ± 3.21%) groups without a significant reduction in total body weight at a p \u3c 0.05 significant level. No change was observed in Wingate peak or mean power (p \u3c 0.05). CONCLUSION: The findings of this study suggest GU Energy Gel supplementation has a more profound impact on aerobic capacity when compared to a Placebo under identical training protocols. However, both GU Energy Gel and Placebo supplementation had a significant effect on aerobic capacity and body fat percentage

    The Impact of Differing Types of Physical Activity on Weight Loss, Strength, VO2 max, and the Various Metabolic Hormones.

    Get PDF
    PURPOSE: The purpose of this investigate the impact of differing types of physical activity on weight loss, strength, VO2 max, and various metabolic hormones. METHODS: Eleven sedentary and overweight male/females participated in this study and were randomly assigned to one of two exercise groups: aerobic training (A) (N = 4, 40 ± 8.7 yrs 165 ± 8.3cm, 89 ± 16 kg), or aerobic training plus resistance training (ART) (N = 7, 43 ± 10 yrs, 171 ± 8.7 cm, 91 ± 12 kg). Training protocols for the two exercise groups consisted of 30 min of aerobic exercise five days per week at 60-70% of heart rate max and 30 minutes of aerobic exercise three days per week at 60-70% of heart rate max plus two days of moderate intensity resistance exercise per week for the (A) and (ART) groups, respectively. Baseline testing consisted of weight, hip, and waist measurements, and body composition analysis using bioelectrical impedance. Participants donated approximately 20 ml of fasting blood for the analysis of clinical chemistry profiles, WBC counts, and the hormones insulin, leptin, and cortisol. Following these assessments, VO2 max, upper-body strength, and lower-body strength was established using standard procedures. All baseline assessments were repeated at 4 and 8 weeks of the study. Statistical analyses utilized a two-way ANOVA with repeated measures for all criterion variables (p\u3c0.05). RESULTS: A significant (p \u3c 0.05) increase in upper and lower body strength was observed in both A and ART groups, however there was no significant difference between groups. A significant group x time interaction (p \u3c 0.05) was observed for body weight (ART: -1.5 ± 0.3 lbs; A: 3 ± 0.5 lbs). No significant (p \u3e 0.05) main effects for group or time were observed for the criterion variables body fat, VO2 max, and the hormones insulin, leptin, and cortisol. Furthermore, neither protocol had a significant impact on body fat or VO2 max. CONCLUSIONS: It can be concluded that aerobic exercise coupled with resistance training for 8 weeks yielded greater results in weight loss than aerobic training alone. No marked changes were noted on the affects of any type of exercise regiment on body composition, VO2 max, or the hormones leptin, insulin, and cortisol over the 8-week study

    Theoretical analysis of the role of chromatin interactions in long-range action of enhancers and insulators

    Get PDF
    Long-distance regulatory interactions between enhancers and their target genes are commonplace in higher eukaryotes. Interposed boundaries or insulators are able to block these long distance regulatory interactions. The mechanistic basis for insulator activity and how it relates to enhancer action-at-a-distance remains unclear. Here we explore the idea that topological loops could simultaneously account for regulatory interactions of distal enhancers and the insulating activity of boundary elements. We show that while loop formation is not in itself sufficient to explain action at a distance, incorporating transient non-specific and moderate attractive interactions between the chromatin fibers strongly enhances long-distance regulatory interactions and is sufficient to generate a euchromatin-like state. Under these same conditions, the subdivision of the loop into two topologically independent loops by insulators inhibits inter-domain interactions. The underlying cause of this effect is a suppression of crossings in the contact map at intermediate distances. Thus our model simultaneously accounts for regulatory interactions at a distance and the insulator activity of boundary elements. This unified model of the regulatory roles of chromatin loops makes several testable predictions that could be confronted with \emph{in vitro} experiments, as well as genomic chromatin conformation capture and fluorescent microscopic approaches.Comment: 10 pages, originally submitted to an (undisclosed) journal in May 201

    Flame or Fizzle? A Comparative Case Study of the SPARC Experience

    Get PDF
    Social Perceiving-Acting Reciprocal Conversations (SPARC) is an emerging approach to large group discussions. SPARC utilizes an iterative approach to group discussions by nesting small fishbowl discussions within a larger whole group discussion. Theoretically, this structure affords reciprocal participant interactions for the negotiation of meaning and increased depth of inquiry. This study takes a detailed look at the experiences of three undergraduates who participated in SPARC during an Educational Psychology course for non-education majors at a large university in the Northeastern United States. Luke, Esmeralda, and Diane participated in SPARC eleven times between January and May

    Enhancing organizational agility within the human resources function

    Get PDF
    Organizational agility describes a firm’s dexterity in making necessary changes to sustain and enhance performance. This mixed methods study examined the nature of agility and the impacts of internal processes on agility within the human resources (HR) function of a telecommunications organization in the United States. Both survey and interview data were collected. Quantitative data were collected and statistically analyzed. Qualitative insights were coded to identify trends in the respective datasets. Study findings indicate the case organization had a moderate degree of agility and that its attunement to the external environment was variable. The data also suggested that leadership style, organizational culture, strategic planning, and communications were four key barriers to creating agility within the HR function. Recommendations to the case organization, organization development practitioners seeking to help HR organizations enhance agility, and researchers are offered

    Computational modeling to elucidate molecular mechanisms of epigenetic memory

    Full text link
    How do mammalian cells that share the same genome exist in notably distinct phenotypes, exhibiting differences in morphology, gene expression patterns, and epigenetic chromatin statuses? Furthermore how do cells of different phenotypes differentiate reproducibly from a single fertilized egg? These are fundamental problems in developmental biology. Epigenetic histone modifications play an important role in the maintenance of different cell phenotypes. The exact molecular mechanism for inheritance of the modification patterns over cell generations remains elusive. The complexity comes partly from the number of molecular species and the broad time scales involved. In recent years mathematical modeling has made significant contributions on elucidating the molecular mechanisms of DNA methylation and histone covalent modification inheritance. We will pedagogically introduce the typical procedure and some technical details of performing a mathematical modeling study, and discuss future developments.Comment: 36 pages, 4 figures, 2 tables, book chapte

    Kindling SPARC: The Emergence of Social Perceiving-Acting Reciprocal Conversations

    Get PDF
    Based on an ecological theory of knowing (see Barab & Plucker, 2002; Barab & Roth, 2006; Gibson, 1986; Young, 2004), Social Perceiving-Acting Reciprocal Conversations (SPARC) is an emerging discussion approach designed to tune agents’ perceptions to the affordances of discussion interactions and to develop their effectivities to act on these affordances. This paper discusses the creation and subsequent iterations of SPARC that emerged in my undergraduate Educational Psychology class between January and May of 2009. Educational implications and future research directions are discussed

    Scaffolding Oral Language for Elementary English Learners in Content Classrooms

    Get PDF
    This project addresses the question: What strategies could be provided to content and English as a Second Language (ESL) teachers to help scaffold oral language use for English Learners in the elementary content classroom? This project was born from the author’s experience as a language teacher and the need to provide language supports for her students in content classes such as science and social studies. Literature regarding second language acquisition, science education, and oral language supports were consulted in the development of this project. A portfolio of resources to support oral language development was created, which includes an example science unit plan that incorporates language goals and activities into content lessons, example anchor charts to support student speech, vocabulary teaching resources, and several slideshows designed to teach other educators about strategies for supporting oral language development in the classroom. The resources submitted for this capstone project are the beginnings of a larger project that the author has launched and will continue to expand in the future. Overall, this capstone project provides a variety of oral language scaffolding resources that educators can use to develop academic language development for their English Learner students
    corecore