Browsing by Subject "resistance"
Now showing 1 - 11 of 11
Results Per Page
Sort Options
Item AEROBIC AND RESISTANCE EXERCISE PROTOCOLS FOR OVERWEIGHT AND OBESE CHILDREN: A SYSTEMATIC REVIEWEstrada, Martin Salmon; Ko, MansooBackground: In recent times, the prevalence of childhood obesity has been increasing in the United States. Obese individuals have been shown to be at an increased risk for developing health complications such as metabolic syndrome, type 2 diabetes (T2DM), and other cardiovascular disorders. Exercise is one of the methods used to prevent and treat obesity. Current exercise recommendations from the U.S. Department of Health and Human Services (USDDHS) and the American College of Sports Medicine (ACSM) are directed to healthy children or obese adults. However, they do not provide detailed exercise recommendations for overweight or obese children. This review derives aerobic and resistance exercise protocols for children with a body mass index (BMI) ≥25 from studies that have administered exercise prescriptions to overweight and obese children. Methods: A systematic review using PubMed, CINAHL, MEDLINE, PEDro, and Cochrane databases was performed. Search terms used were combinations of: obese, overweight, children, adolescent, exercise, aerobic, and resistance. Quality assessment of articles was performed using the PEDro assessment tool. Results: The primary search strategy yielded 10 studies for inclusion in this review. Seven studies utilized aerobic interventions and 3 utilized resistance interventions. The aerobic exercise protocol was derived by calculating the means of exercise parameters from the 7 aerobic studies. The resultant aerobic exercise protocol consisted of 47.1 minutes per session, 4 times per week at an intensity of 61.9% VO2 max or at least 150 bpm utilizing aerobic exercise equipment or aerobic games for at least 11.9 weeks. The resistance exercise protocol was derived by calculating the means of exercise parameters from the 3 resistance studies The resistance exercise protocol resulted in 2 sets of 10 repetitions at 72.5% of the subjects 1 repetition max 2.3 times per week. A mean of 8 exercises were performed per session focusing on both lower and upper body exercises for 12 weeks. Conclusion: Each exercise protocol was derived from studies that showed significant improvements in risk factors associated with metabolic syndrome, T2DM, and other cardiovascular diseases. These exercise protocols provide a viable exercise prescription specifically for risk factor reduction in overweight and obese children.Item Application of Membranes to Treatment of Water Based Exploration and Production Wastes(2010-10-12) Olatubi, Oluwaseun AlfredProduced water and spent drilling fluids from petroleum operations represent a significant expense to companies developing new energy reserves. These spent fluids, seldom recycled, offer a viable source of water resources for oil-field reuse. A major obstacle to reuse is the presence of suspended solid material in the fluids. Such contaminants, if not removed, will not only prevent any reuse but will also impede disposal. The objective of this project was to evaluate membrane filtration as a way to remove suspended and entrained particles to produce re-useable effluents using membranes. Ceramic and Polyvinylidene Flouride (PVDF) hollow fibre membranes were used in laboratory scale experiments in the investigation of the colloidal filtration of field produced spent drilling fluids and produced water. Feed parameter and operational parameter evaluation of ceramic and PVDF hollow fibre membrane filtration of spent drilling fluids and produced water showed that feed concentration, solids in the spent drilling fluid and oil in the produced water, is the most important parameter during membrane filtration. Operational parameter variation showed that high cross flow velocity was beneficial in flux maintenance during spent drilling fluid filtration due to its high solids concentration because of the scouring effect on the cake layer on the membrane surface. Pressure regimens were important in flux decline as relatively high pressures accelerate the consolidation of the concentration polarization layer causing flux decline. High temperatures were generally beneficial for increased flux in the filtration of produced water and spent drilling fluids. Resistance calculations were used to deduce the contribution of individual resistances during the ceramic filtration of produced water and spent drilling fluids and were identified as a real-time tool for monitoring membrane integrity and fouling. Backwashing as a fouling mitigation technique was effective in flux maintenance in ceramic membranes especially in the filtration of produced water; cleaning solutions were effective in flux recovery in ceramic membrane filtration and to a slightly lesser degree in hollow fibre membrane filtration. A methodology in determining the suitability of water based oil field wastes using membranes was developed to help future investigations of this type.Item Characterization of Resistance to Black Spot Disease of Rosa Spp.(2014-12-01) Dong, QianniBlack spot disease (BSD), caused by the fungus Diplocarpon rosae Wolf, is one of the most serious diseases of garden roses. Both complete (vertical) resistance conditioned by dominant Rdr genes and partial (horizontal) resistance (PR) conditioned by multiple genes have been described. The use of resistant rose cultivars would reduce the demand of agrochemical application. The characterization of 16 genotypes using two laboratory assays, the detached leaf assay (DLA) and the whole plant inoculation (WPI) approach, indicated that these were well correlated. Thus either method could be used to assess the resistance of the plants to the BSD. Fifteen diploid hybrid populations from 10 parents segregating for black spot partial (horizontal) resistance were assessed for black spot resistance by quantifying by the percentage of the leaf area with symptoms (LAS) and lesion length (LL) measured by the diameter of the largest lesion in detached leaf assays. Nine of these populations were also evaluated in field trials by rating the incidence of damage due to the fungal infection. The narrow sense heritability of partial resistance to black spot as measured by LAS and LL data of DLA was estimated from 0.3 to 0.4 when calculated with a genetic variance analysis and from 0.7 to 0.9 when generated from mid-parent offspring regression. In the field assessments, the second year assessments were better than the assessments done the first year due to higher and more uniform inoculum levels which minimized problems with escapes. In general there was no or just low correlations between field and DLA assessments of black spot indicating that perhaps these two assessments are measuring different aspects of resistance. The narrow and broad sense heritability estimates from the combined analysis of field assessments is 0.3 and 0.4 respectively. An examination of the assessment data from the laboratory and the field showed that some seedlings were rated as resistant using both approaches. Two microsatellite markers linked with Rdr1 locus and one SCAR marker linked to Rdr3 locus were found to be germplasm specific. The hybrid population ?Golden Gardens? x ?Homerun? that segregates for race 8 resistance was phenotyped for resistance to race 8 and genotyped for 38 SSR markers to assess if any of these SSR markers were associated with Rdr3. This resistance trait from the triploid source segregated non randomly and differentially in haploid and diploid gametes. None of the SSR markers examined were associated with Rdr3.Item Influence of Insulin Resistance on Contractile Activity-Induced Anabolic Response of Skeletal Muscle(2011-02-22) Nilsson, Mats I.Although the long-term therapeutic benefits of exercise are indisputable, contractile activity may induce divergent adaptations in insulin-resistant vs. insulin-sensitive skeletal muscle. The purpose of this study was to elucidate if the anabolic response following resistance exercise (RE) is altered in myocellular sub-fractions in the face of insulin resistance. Lean (Fa/?) and obese (fa/fa) Zucker rats were assigned to sedentary and RE groups and engaged in either cage rest or four lower-body RE sessions over an 8-d period. Despite obese Zucker rats having significantly smaller hindlimb muscles when compared to age-matched lean rats, basal 24-h fractional synthesis rates (FSR) of mixed protein pools were near normal in distally located muscle groups (gastrocnemius, plantaris, and soleus) and even augmented in those located more proximally (P<0.05; quadriceps). Although 2 x 2 ANOVA indicated a significant main effect of phenotype on mixed FSR in gastrocnemius and soleus (P < 0.05), phenotypic differences were partially accounted for by an exercise effect in the lean phenotype. Interestingly, obese rats exhibited a significant suppression of myofibrillar FSR compared to their lean counterparts (P<0.05; gastrocnemius), while synthesis rates of mitochondrial and cytosolic proteins were normal (gastrocnemius and quadriceps), suggesting a mechanism whereby translation of specific mRNA pools encoding for metabolic enzymes may be favored over other transcripts (e.g., contractile proteins) to cope with nutrient excess in the insulin-resistant state. Immunoblotting of the cytosolic fraction in gastrocnemius muscle indicated an augmented phosporylation of eIF4EBP1 (+ 9%) and p70s6k (+85%) in obese vs. lean rats, but a more potent baseline inhibition of polypeptide-chain elongation as evidenced by an increased phospho/total ratio of eEF2 (+78%) in the obese phenotype. Resistance exercise did not improve synthesis rates of myofibrillar, cytosolic, or mitochondrial proteins to the same extent in obese vs. lean rats, suggesting a desensitization to contractile-induced anabolic stimuli in the insulin-resistant state. We conclude that insulin resistance has diverse effects on protein metabolism, which may vary between muscle groups depending on fiber type distribution, location along the proximodistal body axis, and myocellular sub-fraction, and may blunt the anabolic response to voluntary resistance exercise.Item Multi-Location Evaluation of Agronomic Traits in Maize Hybrids(2012-12-12) McKee, Michael 1982-Maize (Zea mays L.) is one of the main crops grown in the United States. Genetic improvement over the last century has seen a shift from using open-pollinated varieties to single cross hybrids. This has resulted in major grain yield gains and improved management methodologies. However, there is still concern about reduced genetic diversity in elite corn germplasm and the potential effects this could have on future maize productivity in the presence of numerous abiotic and biotic pressures. One solution to this issue is the incorporation of exotic germplasm into existing maize improvement programs. This exotic material must be evaluated and characterized because too much or poorly matched exotic material can lead to reduced productivity. The use of multiple environments representative to the target improvement area is the best way to determine the true potential of certain material. The objectives of this research were to: i) estimate the responses of hybrids to aflatoxin and their agronomic performance across a range of environments under inoculation with Aspergillus flavus; ii) identify the hybrids within each group that exhibit the lowest levels of contamination; iii) analyze the relationship between agronomic performance and aflatoxin accumulation; and iv) determine how Genotype x Environment interactions affect these traits. Agronomic data was collected in ten Texas environments in 2005 for hybrids created from yellow, white, and Quality Protein Maize material that was crossed with one of two elite temperate inbred testers, LH195 or LH210. Response to aflatoxin was measured in eight of these environments. U.S. commercial hybrids were used as checks. Significant differences between hybrids were observed at different environments for different traits. Overall the experimental hybrids had lower aflatoxin accumulation than the commercial checks. They also yielded lower and had lower test weights and 1000 kernel weights. However, there were some hybrids that were competitive with the commercial checks for these agronomic traits. The incorporation of this material into established U.S. lines could be beneficial with regards to aflatoxin accumulation and kernel quality, which could ultimately translate to higher yields and crop quality.Item Occurrence and Management of Glyphosate Resistant Amaranthus Weed Species in Central Texas Cotton and Evaluation of Spray Droplet Size Spectra as Affected by Nozzle Design and Herbicide Formulation(2014-08-28) McGinty, Joshua AllanWith the recent confirmation of glyphosate-resistant Amaranthus species in many important agronomic regions of the United States, a study was initiated to identify and document the occurrence of glyphosate resistant common waterhemp in East-central Texas. Accessions of several suspected glyphosate-resistant biotypes of common waterhemp were grown in a greenhouse before receiving rates of glyphosate from 434 to 3468 g ae ha^-1. Dose-response analyses were conducted to provide LD50 values for each accession. LD50 values ranged from 387 to 4549 g ae ha^-1 glyphosate. A study evaluating the efficacy of twelve different weed control programs for common waterhemp and Palmer amaranth control in cotton was conducted in Burleson County, TX in 2012 and 2013. The study was conducted in cotton possessing stacked glyphosate-, glufosinate-, and dicamba-tolerant technologies. Preplant and preemergence treatments included fomesafen, pendimethalin, prometryn, pyrithiobac, S-metolachlor, and trifluralin. These treatments were followed by a variety of early- and mid-postemergence treatments. Preplant and preemergence treatments resulted in 81 to 100% control of Palmer amaranth and common waterhemp with the exception of pyrithiobac, which provided only 29 to 60% control of these species. Following early- and mid-postemergence applications, 92 to 100% control of these species was obtained. Applications of pendimethalin PRE followed by pyrithiobac EPOST and glufosinate MPOST in 2013 provided lower control of both species (92 to 93 %) than all other treatments evaluated in the study 14 days after MPOST applications. With the potential commercialization of synthetic auxin-tolerant crops, there is an increased need for understanding of the influence of spray nozzle design and herbicide formulation on physical spray drift reduction. A study was conducted in a low speed wind tunnel utilizing laser diffraction technology to analyze the droplet size spectra produced by different spray nozzles and herbicide formulations. Nozzles utilizing a pre-orifice design or a combination of pre-orifice and air-inclusion design were observed to produce significantly larger spray droplets than those without these features. Herbicide formulations were shown to have a significant influence on droplet size as well. Different herbicide formulations were observed to decrease the production of drift-prone fine droplets by as much as 64%.Item Screening for resistance to cucurbit yellow stunting disorder virus, gummy stem blight, and monosporascus root rot and detection of RAPD markers associated with QLT for soluble solids, sugars, and vitamin C in melon (Cucumis melo l.)(Texas A&M University, 2005-02-17) Sinclair, Jonathan WalkerCucurbit yellow stunting disorder virus (CYSDV) is a relatively new virus affecting cantaloupe production in South Texas and worldwide. No resistant commercial cultivars are available. A cross of ?Dulce? (susceptible) x ?TGR1551? (resistant) was made and populations were developed for screening. Although no complete resistance was recovered, ?TGR1551? showed some tolerance and may be useful in breeding efforts. Sugar components such as sucrose, fructose, glucose, and total soluble solids are major factors in determining mature melon fruit sweetness, and Vitamin C is important for human health. A F2 population was developed from the melon cross ?Dulce? (high values) x ?TGR1551? (low values) and bulked segregant analysis was used to detect random amplified polymorphic DNA (RAPD) markers associated with quantitative trait loci (QTL) for each trait. Out of 500 primers, fifteen RAPD markers were found to be significantly associated with fruit quality QTL. These markers could be useful in a marker assisted selection program to transfer these genes into a low quality cultivar or breeding line to enhance fruit quality. Gummy stem blight (Didymella brioniae) affects melon production in South Texas as well as other melon production areas in the U.S. A cross between ?TMS? (susceptible) and PI 140471 (resistant) was made and a F2 population was screened with a strain of the disease from South Texas. F2 plants exhibited symptoms ranging from resistant to susceptible. PI 140471 may be useful in developing commercial varieties of melon resistant to the disease in Texas. Monosporascus root rot and vine decline (Monosporascus cannonballus) affects melon production in South Texas as well as other melon production areas in the US. A cross was made between ?TGR1551? (moderately resistant) and ?Deltex? (resistant) to develop a F2 population. Both parents and the F2 were planted in infested soil. Once symptoms appeared, plant roots were removed from the soil and rated. ?TGR1551? showed greater resistance than ?Deltex? and should be utilized in breeding to develop improved resistant cultivars.Item Selenium nutrition of Morone hybrids including dietary requirements, bioavailability, toxicity and effects on immune responses and disease resistance(Texas A&M University, 2006-08-16) Jaramillo, Francisco , JrAquacultural production of hybrid striped bass (HSB) Morone chrysops ?? M. saxatilis is highly vulnerable to losses from bacterial pathogens such as Streptococcus iniae. Therefore, research was conducted to evaluate various dietary factors that may enhance immunocompetence and disease resistance of HSB. In the first experiment, purified and practical diets were supplemented with β-glucan and selenium in a factorial arrangement and fed to juvenile HSB for 6 wk followed by a S. iniae challenge. Weight gain (WG) and feed efficiency (FE) were higher for fish fed either practical diets or purified diets supplemented with selenium, but not those supplemented with β-glucan. Survival after disease challenge for fish fed the selenium-supplemented practical and purified diets was 75% and 35%, respectively. Because selenium supplementation also improved WG and FE, and because selenium and vitamin E have complementary biochemical functions, a second experiment evaluated potential interactions by feeding purified diets with or without vitamin E or sodium selenite (Na2SeO3), singularly or in combination, for 12 wk. Dietary selenium significantly affected whole-body selenium concentration but there was no effect of dietary selenium, vitamin E or their interaction on WG, FE, survival or blood neutrophil oxidative radical production. Three additional 12-wk experiments were conducted to establish selenium essentiality, toxicity, tissue deposition, dietary requirements, bioavailability and nonspecific immune responses using purified diets with a basal selenium level of 0.11 mg/kg. In one experiment, diets had selenium concentrations of 1.19, 2.00, 5.17 and 21.23 mg/kg from Na2SeO3. Another experiment had selenium concentrations of 0.90, 1.26 and 2.55 mg/kg from seleno-DL-methionine. The third trial utilized selenium from Na2SeO3, seleno-DL-methionine and selenium yeast at approximately 0.15, 0.30 and 0.60 mg/kg diet. No overt selenium deficiency signs were observed in any of the three latter experiments, but based on selenium retention values, a minimum dietary requirement of approximately 0.1 mg/kg was estimated. Selenium toxicity was observed in fish fed the diet containing more than 20 mg/kg. Bioavailability of selenium sources was ranked as seleno-DL-methionine > selenium yeast > Na2SeO3.Item The effects of concurrent training on performance variables in previously untrained males(Texas A&M University, 2005-02-17) Glowacki, Shawn PhilipResearch has shown conflicting results involving interference of strength development with combined resistance and endurance training. Purpose: To examine if endurance training and resistance training performed concurrently would produce different performance and physiological results when compared to each type of training alone. Methods: Forty-five untrained males were recruited and randomly assigned to one of three 12 wk training groups. An endurance training (ET, N=12) group trained by running (2-3 days/week, 20-40 min, 65- 80% HRR), a resistance training (RT, N=13) group performed a resistance training program (2-3 days/week, 3 sets/8 exercises, 6-10 reps, 75-85% 1RM), and a concurrent training (CT, N=16) group performed both the endurance and resistance training programs (5 days/week, even # week 3 endurance/2 resistance workouts, odd # week 3 resistance/2 endurance workouts). All groups were tested for all the following variables prior to and following training: percent body fat, VO2max, isokinetic-maximal torque and avg. power at two speeds, 1RM leg press, 1 RM bench press, vertical jump, lower body power (as calculated by the Lewis formula) and 40-yard dash time. Results: Percent body fat was significantly (p≤.05) decreased in both the ET and CT groups. Only the ET group significantly improved VO2max (+8.24%). Minimal changes were found for any of the isokinetic measurements. The ET, RT, and CT groups demonstrated significant improvements in leg press (20.4, 40.8, and 39.4%) and bench press (7.5, 30.5 and 21.2%) 1 RM. RT and CT 1 RM improvements were similar and significantly greater than the ET group. Only the RT group significantly increased power. No group showed a significant change in vertical jump or 40-yard dash time. Conclusions: Findings indicate that endurance training does not interfere with strength development, but resistance training appears to hinder development of maximal aerobic capacity.Item The relationship between the level of antibiotic use and resistance among enteric bacteria in a multi-site integrated human and swine population(2009-05-15) Christian, Kristi LynnThe objective of this longitudinal study was to study the relationship between changes in prevalence of resistant enteric bacteria associated with mean monthly doses (MMD) of various antibiotics used in each of two host species. From January 2004 ? January 2007, monthly composite swine fecal samples and human wastewater samples representing various production and occupational cohorts, respectively, were collected from 19 geographically unique locations in east- and south-central Texas. Bacterial isolates cultivated on CHROMagar-E.coliTM and DifcoTM mEnterococcus (ME) were tested for susceptibility to multiple antibiotics by microbroth dilution using the SensititreTM system. The relationship between the prevalence of resistant bacteria, sampling period, and antibiotic use within each host species was assessed in a generalized linear model adjusted for the dependence of responses within location using a binomial distribution and logit link function in STATA? ver. 9.2. For the swine E. coli isolates, the relationship between tetracycline resistance and level of chlortetracycline (CTC) use in swine illustrated a dose-response relationship, with odds ratios (OR) of 1.20 and 1.81 (P < 0.05) for second- and third-level categories of MMD relative to baseline (zero-use) respectively. When considered by swine production groups, intake boar isolates had an elevated relative odds of resistance to tetracycline (OR = 1.51, P < 0.05), and the nursery units had an elevated odds (OR = 2.61, P < 0.05) of exhibiting resistance to ceftiofur, relative to pigs housed in the farrowing barns. Regarding swine Enterococci isolates, those swine from locations that utilized tylosin had an elevated OR of 3.54 (P < 0.05) of exhibiting resistance to tylosin, relative to those locations that used no tylosin. At this juncture, an apparent occupational risk of harboring tetracycline-resistant E. coli, and the apparent sparing effect (Enterococcus spp.) associated with exposure to swine production, remain unexplained. This study demonstrated that the prevalences of tetracycline- and tylosin-resistant enteric bacteria swine were dependent on CTC and tylosin use in feed, respectively. Swine production group-effects on the prevalence of tetracycline, ceftiofur, and erythromycin resistance were also important. This study provides a better understanding of the relationships between antibiotic prescribing practices at the ecologic level and the relative odds of carriage of resistant bacteria within two host species in a vertically integrated agri-food system.Item Towards Stunt-Free Lonren Reniform Nematode Resistance by Dissection of an Alien R-Gene Chromosome Segment and Detection of Significant Fungal Interactions(2014-07-07) Zheng, XiutingReniform (Rotylenchulus reniformis) nematodes cost US cotton growers over 130 million dollars per year. Genetic resistance of the wild African species Gossypium longicalyx to reniform nematodes was previously transferred into upland cotton (Gossypium hirsutum L.). LONREN and other cotton lines containing the responsible gene, Ren^(lon), are highly nematode-resistant, but when grown in nematode-infested fields, the seedlings and plants became "stunted". Hypothesized causes include hypersensitivity reaction, per se, and/or increased susceptibility to soil pathogens. My research objectives have been: [1] to develop Ren^(lon)-linked markers and map the Ren^(lon) region at high resolution, [2] to recombine Ren^(lon) and nearby loci and determine if ?stunting? is due to linkage drag, [3] to create genomic and germplasm resources for genetic manipulation of chromosome-11, especially Ren^(lon), and [4] to determine if "stunting" is due solely to plant-nematode interactions or involves additional pathogens. Putative SNPs between G. hirsutum and G. longicalyx were collaboratively sequence-aligned to the D5 reference genome. By selecting SNPs aligned to the Ren^(lon)-homeologous region and screening them against a genetic panel, we identified 85 as Ren^(lon) -linked. To enable large-scale SNP applications, we developed inexpensive methods for high-throughput non-destructive seed DNA extraction for PCR-based genotyping. We then high-resolution mapped 10 SNPs in the proximal alien segment near Ren^(lon). We chose the two closest Ren^(lon)-flanking SNPs and used them for marker-assisted selection to identify 5 recombinants from 17,600 BC1F1 seed. Subsequent progeny tests indicated 2 of the 5 recombinants were free of "stunting" and that 1 seems to be segregating for nematode resistance. Contingent on verification of the resistance, the results indicate that stunting of LONREN seedlings is indeed due to linkage drag, not hypersensitivity, per se. To determine if "stunting" can be ascribed solely to hypersensitivity-induced root damage, we conducted three replicated growth chamber experiments with multiple genotypes, pasteurized and natural soils, and several pathogen treatments. The results showed that Thielaviopsis root rot alone can cause severe seedling "stunting", but not the nematodes, alone. Moreover, they showed that LONREN-like genotypes are differentially sensitive to the combined presence of reniform nematodes and Thielaviopsis, and become more severely stunted.