From Mission to Competition: The Experiences of 10 LDS Missionary Student-Athletes Returning to Competition in the National Collegiate Athletic Association Division I

The purpose of the current study was to explore the experiences of LDS missionary student-athletes returning to competition in the National Collegiate Athletic Association (NCAA) Division I (DI). Using Consensual Qualitative Research methods (CQR; Hill, 2012) including a semi-structured interview guide, 10 DI student-athletes/returned LDS missionaries were interviewed regarding their experience (i.e., mean age of 25 years; baseball, cross-country/track and field, football, and swimming). A research team with five members constructed four domains and 16 categories representing DI student-athlete/returned LDS missionary chronological identity changes during this experience: (a) the development of an LDS missionary identity; (b) challenges associated with returning to DI student-athlete identity; (c) benefits of mission identity on DI student-athlete identity; and (d) practical implications for sport psychology professionals and other support staff. Suggestions for future research are also given

Comparison of Regional Body Composition Estimates Obtained from Dual-energy X-ray Absorptiometry and Single-frequency Bioelectrical Impedance Analysis

The anatomical distribution of fat mass (FM) and lean mass (LM) is significant for health and athletic performance. Dual-energy x-ray absorptiometry (DXA) is often used for regional body composition analysis but is not portable, often inaccessible, and costly, while single-frequency bioelectrical impedance analysis (SFBIA) is a more affordable and accessible alternative. PURPOSE: The purpose of this analysis was to compare regional body composition estimates obtained via DXA and SFBIA. METHODS: After an overnight food and fluid fast, 102 adults (64 F, 38 M; age: 29.2 ± 13.4 y; BMI: 24.3 ± 3.9 kg/m2; BF%: 24.6 ± 8.3%) underwent assessments via DXA and SBFIA, each of which provided estimates of FM and LM for the whole body, torso, legs, and arms. DXA scans were performed using custom-made foam blocks to enhance accuracy of regional body composition estimates. SFBIA was performed using an 8-lead device with a 12-channel multiplexer. Both DXA and SFBIA were performed in the supine position. DXA was designated as the criterion method, and body composition estimates were compared using paired-samples t-tests using a Bonferroni-corrected significance level of p ≤ 0.00625. Additional evaluations were conducted using the correlation coefficient (r), constant error (CE), standard error of the estimate (SEE), and total error (TE). RESULTS: Correlations between DXA and SFBIA were high, and the magnitude of errors was generally small: LMTOTAL (r: 0.97; CE: 1.4 kg; SEE: 2.7 kg; TE: 2.9 kg), LMLEGS (r: 0.85; CE: -0.3 kg; SEE: 2.0 kg; TE: 2.1 kg), LMTORSO (r: 0.92; CE: 1.0 kg; SEE: 2.2 kg; TE: 2.5 kg), LMARMS (r: 0.96; CE: 0.6 kg; SEE: 0.6 kg; TE: 0.8 kg), FMTOTAL (r: 0.95; CE: -2.3 kg; SEE: 2.6 kg; TE: 3.5 kg), FMLEGS (r: 0.83; CE: -1.0 kg; SEE: 1.2 kg; TE: 2.0 kg), FMTORSO (r: 0.90; CE: -1.3 kg; SEE: 2.2 kg; TE: 2.6 kg), and FMARMS (r: 0.89; CE: -0.1 kg; SEE: 0.5 kg; TE: 0.5 kg). Despite the relatively small magnitude of differences in FM and LM estimates between DXA and SFBIA, results of paired-samples t-tests indicated that all differences were statistically significant (p \u3c 0.0001), with the exception of LMLEGS (p=0.13) and FMARMS (p=0.11). CONCLUSION: Despite the fact that body composition estimates for most regions exhibited statistically significant differences between DXA and SFBIA, the strong correlations (r: 0.83 to 0.97) and relatively low magnitude of error (CE: -2.3 to 1.4 kg; TE: 0.8 to 3.5 kg) indicate that SFBIA may be an acceptable alternative to DXA when regional body composition is being evaluated and DXA is unavailable. However, additional research is needed to determine the ability of SFBIA to accurately track changes in regional body composition over time. Due to its low cost, portability, and ease of use, the presently examined SFBIA device may represent a useful tool for the evaluation of regional body composition when more advanced methods are unavailable

Validity of Infrared 3-dimensional Scanning for Estimation of Body Composition: A 4-Compartment Model Comparison

Multiple infrared 3-dimensional (3D) scanning technologies exist, including time of flight (ToF) scanners and structured light scanners with static (SL-S) and dynamic (SL-D) configurations. ToF scanners measure depth by using the round-trip time of reflected photons, whereas SL scanners measure deformations in light patterns and allow for creation of a depth image using geometric triangulation. Recently, 3D scanning technologies have been proposed as novel methods of body composition assessment. PURPOSE: The purpose of this analysis was to examine the validity of four different commercially-available 3D scanners for estimation of body fat percentage (BF%) as compared to a 4-compartment (4C) model criterion. METHODS: After an overnight fast, 101 adults (63 F, 38 M; age: 29.3 ± 13.5 y; BMI: 24.3 ± 3.9 kg/m2; BF%: 24.6 ± 8.3%) completed assessments via dual-energy x-ray absorptiometry (DXA), air displacement plethysmography (ADP), bioimpedance spectroscopy (BIS), a standard body mass scale, and four infrared 3D scanners. Two scanners (3DSSL-D1; 3DSSL-D2) utilized structured light scanning with a dynamic configuration, one utilized structured light scanning with a static configuration (3DSSL-S), and one utilized time-of-flight technology (3DSToF). Using the equation of Wang et al. (2002), a criterion 4C estimate of BF% was obtained using DXA for bone mineral, ADP for body volume, scale for body mass, and BIS for total body water. BF% estimates were compared using one-way ANOVA with Bonferroni adjustment for multiple comparisons, and additional evaluations were conducted using the correlation coefficient (r), constant error (CE), standard error of the estimate (SEE), total error (TE), and 95% limits of agreement (LOA). RESULTS: Estimates of BF% did not significantly differ between 4C and any of the 3D scanners. However, metrics of group, individual, and prediction errors varied between scanners: 3DSSL-D1: p=1.0; CE: 0.4%; r: 0.91; SEE: 2.5%; TE: 3.6%; LOA: ±7.0%; 3DSSL-D2: p= 1.0; CE: 0.8%; r: 0.86; SEE: 4.2%; TE: 4.7%; LOA: ±9.2%; 3DSSL-S: p= 1.0; CE: 1.0%; r: 0.81; SEE: 4.0%; TE: 5.0%; LOA: ±9.7%; 3DSToF: p=0.08; CE: -2.9%; r: 0.86, SEE: 2.5%; TE: 5.2%; LOA: ±8.6%. CONCLUSION: All three structured light scanners exhibited low magnitudes of group error (CE ≤ 1%) and may be valid assessment methods when analyzing the body composition of groups. 3DSSL-D1 exhibited the lowest group-level error (i.e. CE), prediction errors (i.e. SEE; TE), and individual error (i.e. LOA) of all scanners. Therefore, this device was deemed the most valid 3D scanner for body composition assessment. 3DSSL-D2, 3DSSL-S, and 3DSToF exhibited comparable TE, although group-level error was lower in 3DSSL-D2 and 3DSSL-S, while the SEE and individual-level error was lower for 3DSToF. However, individual-level errors were relatively high with all scanners (LOA ≥ 7%), which calls into question the utility of these methods for assessing the body composition of individuals. Nonetheless, additional research is needed regarding the ability of 3DS to successfully detect changes in body composition over time

Validity of Four-Compartment Model Body Fat Using Single- or Multi-frequency Bioelectrical Impedance Analysis to Estimate Body Water

Most common body composition assessment techniques make assumptions about the body, including the density and hydration of fat-free mass (FFM). An advantage of the four-compartment (4C) model is the ability to take these FFM characteristics into account when assessing body composition, thus reducing potential error. The total body water (TBW) estimate utilized in 4C models is particularly important due to the large contribution of water to an adult human’s total body mass (~40 - 70%) and FFM (~68 - 81%); however, the impact of utilizing different estimates of TBW within 4C model has not been fully explored. PURPOSE: The purpose of this investigation was to examine the validity of body fat percentage (BF%) estimates produced by 4C models utilizing single- or multi-frequency bioelectrical impedance analysis (BIA) TBW estimates as compared to a criterion 4C with TBW from bioimpedance spectroscopy (BIS). METHODS: After an overnight food and fluid fast, a sample of 101 adults (63 F, 38 M; age: 29.3 ± 13.5 y; BMI: 24.3 ± 4.0 kg/m2; BF%: 24.5 ± 8.3%) completed assessments via dual-energy x-ray absorptiometry (DXA), air displacement plethysmography (ADP), BIS, single-frequency BIA (SFBIA), multi-frequency BIA (MFBIA) and a body mass scale. A criterion 4C model (4CBIS) estimate of BF% was obtained using DXA for bone mineral, ADP for body volume, scale for body mass, and BIS for TBW. BIS was used as the reference TBW method due to its more direct estimation of TBW via mathematical procedures (i.e. Cole modeling and mixture theories) as compared to the prediction equations used by BIA. Alternate 4C estimates of BF% were produced using TBW values from MFBIA (4CMFBIA) and SFBIA (4CSFBIA). BF% estimates were compared using one-way ANOVA, and additional evaluations were conducted using the coefficient of determination (R2), constant error (CE), total error (TE), and 95% limits of agreement (LOA). RESULTS: BF% did not differ between 4CBIS (24.5 ± 8.3%), 4CMFBIA (24.4 ± 8.9%), and 4CSFBIA (25.7 ± 8.3%; p=0.52). 4CMFBIA exhibited negligible CE (-0.1 ± 2.3%), R2 of 0.97, TE of 2.3%, and LOA of 4.4%. 4CSFBIA exhibited a small CE (1.2 ± 1.2%), R2 of 0.98, TE of 1.6%, and LOA of 2.3%. CONCLUSION: At the group level, BF% estimates did not differ between any 4C model, indicating that both SFBIA and MFBIA can serve as viable alternatives to BIS for TBW estimation. Although the magnitude of group error (i.e. CE) was slightly smaller in 4CMFBIA, the individual error (i.e. LOA) and total error were smaller in 4CSFBIA,indicating that SFBIA TBW estimates may be more appropriate when tracking body composition changes within individuals using a 4C model. While the MFBIA and SFBIA technologies employed in the present study exhibited good validity, these results may not be attributable to all BIA analyzers. The quality of assessment device, affordability, portability and ease of use should be considered when utilizing an impedance-based technology for TBW estimation in a 4C model

Reaction of O2 with a di-iron protein generates a mixed valent Fe2+/Fe3+ center and peroxide

The gene encoding the cyanobacterial ferritin SynFtn is up-regulated in response to copper stress. Here, we show that, while SynFtn does not interact directly with copper, it is highly unusual in several ways. First, its catalytic diiron ferroxidase center is unlike those of all other characterized prokaryotic ferritins and instead resembles an animal H-chain ferritin center. Second, as demonstrated by kinetic, spectroscopic, and high-resolution X-ray crystallographic data, reaction of O2 with the di-Fe2+ center results in a direct, one-electron oxidation to a mixed-valent Fe2+/Fe3+ form. Iron–O2 chemistry of this type is currently unknown among the growing family of proteins that bind a diiron site within a four α-helical bundle in general and ferritins in particular. The mixed-valent form, which slowly oxidized to the more usual di-Fe3+ form, is an intermediate that is continually generated during mineralization. Peroxide, rather than superoxide, is shown to be the product of O2 reduction, implying that ferroxidase centers function in pairs via long-range electron transfer through the protein resulting in reduction of O2 bound at only one of the centers. We show that electron transfer is mediated by the transient formation of a radical on Tyr40, which lies ∼4 Å from the diiron center. As well as demonstrating an expansion of the iron–O2 chemistry known to occur in nature, these data are also highly relevant to the question of whether all ferritins mineralize iron via a common mechanism, providing unequivocal proof that they do not

A direct-to-drive neural data acquisition system

Driven by the increasing channel count of neural probes, there is much effort being directed to creating increasingly scalable electrophysiology data acquisition (DAQ) systems. However, all such systems still rely on personal computers for data storage, and thus are limited by the bandwidth and cost of the computers, especially as the scale of recording increases. Here we present a novel architecture in which a digital processor receives data from an analog-to-digital converter, and writes that data directly to hard drives, without the need for a personal computer to serve as an intermediary in the DAQ process. This minimalist architecture may support exceptionally high data throughput, without incurring costs to support unnecessary hardware and overhead associated with personal computers, thus facilitating scaling of electrophysiological recording in the future.National Institutes of Health (U.S.) (Grant 1DP1NS087724)National Institutes of Health (U.S.) (Grant 1R01DA029639)National Institutes of Health (U.S.) (Grant 1R01NS067199)National Institutes of Health (U.S.) (Grant 2R44NS070453)National Institutes of Health (U.S.) (Grant R43MH101943)New York Stem Cell FoundationPaul Allen FoundationMassachusetts Institute of Technology. Media LaboratoryGoogle (Firm)United States. Defense Advanced Research Projects Agency (HR0011-14-2-0004)Hertz Foundation (Myhrvold Family Fellowship

Uranium nitride-silicide advanced nuclear fuel: Higher efficiency and greater safety

The development of new nuclear fuel compositions is being driven by an interest in improving efficiency/lowering cost and increasing safety margins. Nuclear fuel efficiency is in large measure a function of the atomic density of the uranium, that is, the more fissionable uranium available per unit volume the less fuel volume that is required. Proliferation concerns limit the concentration of fissile 235U, and thus attention is directed to higher overall uranium content fuel. Among the options are the high temperature phases U3Si2 and composite UN- U3Si2 where the design would have the more water-stable U3Si2 surround the more soluble, but higher uranium density UN grains. (Uranium metal of course has the highest atomic density, however its low melting point, high degree of swelling under irradiation, and chemical reactivity eliminate it from consideration.) Another advantage of the nitride and silicide phases are their high thermal conductivity, greatly exceeding the current standard UO2 fuel, with the high conductivity potentially allowing the fuel to operate at a higher power density. Please click Additional Files below to see the full abstract

Tuning of Human Modulation Filters Is Carrier-Frequency Dependent

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Electron transfer from haem to the di-iron ferroxidase centre in bacterioferritin

The iron redox cycle in ferritins is not completely understood. Bacterioferritins are distinct from other ferritins in that they contain haem groups. It is acknowledged that the two iron motifs in bacterioferritins, the di-nuclear ferroxidase centre and the haem B group, play key roles in two opposing processes, iron sequestration and iron mobilisation, respectively, and the two redox processes are independent. Herein, we show that in Escherichia coli bacterioferritin, there is an electron transfer pathway from the haem to the ferroxidase centre suggesting a new role(s) haem might play in bacterioferritins