What are the maximum protein requirements of strength athletes? A systematic review

Protein intakes above the recommended dietary allowance (RDA) for adult males have been suggested to be essential in accreting lean body mass, particularly in active individuals. Though, what is the maximum protein requirement of strength athletes in order to maximise their performance. A systematic review was conducted on all primary literature to establish the maximum protein requirements of strength athletes. A comprehensive search strategy involving searches of six electronic databases and ‘grey’ literature were conducted. The search was restricted to studies published after 1986 to the present day. All primary research literature that presented the effect of total dietary protein intake on lean body mass was included. Studies that met the inclusion criteria were assessed for methodological quality using the Downs and Black checklist. 4 studies were identified that met the inclusion criteria, although only 3 studies met the quality assessment criteria; two randomised trials and one non-randomised trial. Statistically non-significant trends (p>0.05) deriving from muscle mass measurements, determined that the maximum protein requirement for strength athletes to be a moderate quantity of 1.4g/kg Bw/day. Similar results were shown in all three studies. There is a sparsity of evidence and an inconsistency in the methodological designs between trials, regarding what the maximum protein requirement of strength athletes to be. Yet, it is likely to be a moderate protein intake, rather than a high protein intake

Improved Performance of the ECR Waveguide Plasma Cathode with Permanent Magnets

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83622/1/AIAA-2010-6519-570.pd

Characterization of a Waveguide ECR Plasma Source

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76786/1/AIAA-2008-4535-674.pd

Underwater operation of a DBD plasma jet

A plasma jet produced in water using a submerged ac excited electrode in a coaxial dielectric barrier discharge configuration was studied. Plasma jet formation was found to occur only while the source was submerged. Plasma jet operation was characterized with and without gas flow. It was found that over 60% of the discharge power was deposited into the water and did not vary appreciably with excitation frequency. Presumably the remaining power fraction went into excitation, ionization and local electrode heating. Emission spectra of the jet revealed nitrogen, hydrogen, hydroxyl and oxygen emission lines. Operation of the plasma jet in water containing the oxidation–reduction indicator methylene blue dye resulted in a marked clearing of the water as observed visually and with a spectrophotometer, suggesting plasma-induced chemical reactivity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85414/1/psst10_2_025001.pd

Magnetically Enhanced Inductive Source for Electric Propulsion Applications

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76941/1/AIAA-2007-5294-339.pd

Characterization of the evolution of underwater DBD plasma jet

An air plasma jet formed underwater using a coaxial DBD electrode configuration with gas flow is being studied for water treatment applications. The arc-like behavior of the discharge in the absence of any obvious return electrode is not well understood. This study seeks to understand the underlying nature of the arc-like jet mode by studying the evolution of the discharge from microdischarge to jet mode. Photographic and spectroscopic data are used to develop a phenomenological model of discharge evolution. Time-averaged spectra were used to assign an average plume and electron temperature. Calculated jet temperatures were consistent with observed affects such as melting and oxide layer formation on a downstream substrate. The capacity of the microdischarge mode to decompose organic dye in water as a function of time, confirmed previously in the jet mode, was also demonstrated in the absence of the jet.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90806/1/0963-0252_20_3_034018.pd

Genetics of tendon properties: In vivo studies in asymptomatic men and women

In recent years, research interest has increased regarding the influence of genetic factors on health, physical activity, and sports research. This is achieved through research study designs including ‘genetic variation’ as an independent variable. These studies aim to link gene variants (common difference in the genome of a population) with a trait of interest (phenotype), known as ‘genetic association’. Albeit, these genetic factors potentially only have a small influence. The aims of the present study were to determine the gene variants within genes that encode for proteins involved in homeostatic balance of tendon physiology, and the contribution to interindividual variability in patellar tendon structural and mechanical properties. Genotype and phenotype data was collected from 84 asymptomatic men and women (aged 18-39 years). Gene variants in the COL5A1 and MMP3 genes were not associated with the variability in the patellar tendon phenotypes, in either sex (COL5A1 rs12722 –Male/Female - Volume, P = 0.936/0.938; Young’s Modulus, P = 0.897/0.227; Z-scores, P = 0.635/0.896: MMP3 679620 & 591058 – Male/Female – Volume, P = 0.796/0.532; Young’s Modulus, P = 0.238/0.680; Z-scores, P = 0.346/0.862: MMP3 650108 – Male/Female – Volume, P = 0.952/0.676; Young’s Modulus, P = 0.170/0.557; Z-scores, P = 0.681/0.531). Furthermore, a polygenic profile including these gene variants could not account for the interindividual variability in patellar tendon properties (Male/Female - Volume, P = 0.359/0.949; Young’s Modulus, P = 0.073/0.067; Z-scores, P = 0.110/0.579). In conclusion, the data suggest that tendon properties are not influenced by the genetic variants studied here. In addition, there are no sex-specific associations. The research on gene variants and their influence on the risk of tendon injury and tendon properties remain quite limited, and the preliminary nature of this research, makes potential genetic influences difficult to quantify at this time. Continued investigations are encouraged into these genes/proteins named here (MMP3, COL5A1), as well as others that may influence the maintenance of tendon homeostasis. Future advances in determining the genetic components of tendon properties in an asymptomatic population may have implications for our understanding of the aetiology of tendinopathies, as well as physical performance potential

PHASE VARIATION OF CLOSTRIDIUM DIFFICILE VIRULENCE FACTORS

Clostridium difficile is a Gram-positive spore-forming anaerobe and the leading cause of antibiotic-associated diarrheal disease in the United States. C. difficile produces two toxins, TcdA and TcdB, that are necessary for diarrheal disease symptoms. Colonization of the intestine is a necessary prerequisite to diarrheal disease symptoms. C. difficile produces flagella that aid not only in bacterial motility, but adherence to intestinal tissue. SigD, a flagellar alternative sigma factor in the early stage flagellar (flgB) operon, indirectly activates expression of the tcdA and tcdB genes. Both flagella and toxins are C. difficile virulence factors that synergistically promote diarrheal disease symptoms, pathology, and inflammation. Therefore, factors that regulate expression of the flgB operon affect not only motility, but toxin production and the virulence of C. difficile. The main objective of the research described in this dissertation was to identify and characterize a genetic mechanism controlling co-regulated flagellar and toxin gene expression in C. difficile. In Chapter 2, we identified a “flagellar switch” located upstream of the flgB operon, that mediates the phase variable production of flagella and toxins in C. difficile. Bacteria with the sequence in one orientation produced flagella, were motile and secreted the toxins ("flg ON"). Bacteria with the sequence in the inverse orientation were aflagellate and showed decreased toxin secretion ("flg OFF"). We determined that the tyrosine recombinase RecV is required for inversion of the flagellar switch in both directions. In Chapter 3, we found a single strain family, designated as “ribotype 012”, of C. difficile exhibits low frequency inversion of the flagellar switch in laboratory-adapted, environmental, and clinical isolates. In Chapter 4, we demonstrated that Rho factor is required for flagellar phase variation in C. difficile. We hypothesize that Rho factor directly terminates transcription in the leader RNA of the flgB operon in flg OFF bacteria. Future studies will assess the virulence contribution of flagellar and toxin phase variation to host infection dynamics, outcome, and transmission. Phase variable flagellar motility and toxin production suggests that these important virulence factors have both advantageous and detrimental effects during the course of infection.Doctor of Philosoph

Genetics of tendon properties : in vivo studies in asymptomatic men and women

In recent years, research interest has increased regarding the influence of genetic factors on health, physical activity, and sports research. This is achieved through research study designs including ‘genetic variation’ as an independent variable. These studies aim to link gene variants (common difference in the genome of a population) with a trait of interest (phenotype), known as ‘genetic association’. Albeit, these genetic factors potentially only have a small influence. The aims of the present study were to determine the gene variants within genes that encode for proteins involved in homeostatic balance of tendon physiology, and the contribution to interindividual variability in patellar tendon structural and mechanical properties. Genotype and phenotype data was collected from 84 asymptomatic men and women (aged 18-39 years). Gene variants in the COL5A1 and MMP3 genes were not associated with the variability in the patellar tendon phenotypes, in either sex (COL5A1 rs12722 –Male/Female - Volume, P = 0.936/0.938; Young’s Modulus, P = 0.897/0.227; Z-scores, P = 0.635/0.896: MMP3 679620 & 591058 – Male/Female – Volume, P = 0.796/0.532; Young’s Modulus, P = 0.238/0.680; Z-scores, P = 0.346/0.862: MMP3 650108 – Male/Female – Volume, P = 0.952/0.676; Young’s Modulus, P = 0.170/0.557; Z-scores, P = 0.681/0.531). Furthermore, a polygenic profile including these gene variants could not account for the interindividual variability in patellar tendon properties (Male/Female - Volume, P = 0.359/0.949; Young’s Modulus, P = 0.073/0.067; Z-scores, P = 0.110/0.579). In conclusion, the data suggest that tendon properties are not influenced by the genetic variants studied here. In addition, there are no sex-specific associations. The research on gene variants and their influence on the risk of tendon injury and tendon properties remain quite limited, and the preliminary nature of this research, makes potential genetic influences difficult to quantify at this time. Continued investigations are encouraged into these genes/proteins named here (MMP3, COL5A1), as well as others that may influence the maintenance of tendon homeostasis. Future advances in determining the genetic components of tendon properties in an asymptomatic population may have implications for our understanding of the aetiology of tendinopathies, as well as physical performance potential.EThOS - Electronic Theses Online ServiceGBUnited Kingdo