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Purpose: The purpose of this study was to determine whether ankle brace use in university-level varsity volleyball athletes affected their 3-step spike jump height and whether certain types of ankle braces have a greater effect on jump height. Methods: Nine male university-level varsity volleyball athletes participated in a repeated-measures design study in which each athlete performed three 3-step volleyball spike jumps in 3 ankle brace conditions (soft, rigid, and no brace). Vertical jump height was measured by the Vertec device and video motion analysis at a university biomechanics research laboratory. Results: Vertical jump heights were significantly lower in both brace conditions (soft, 2.3 cm, standard deviation [SD] 1.2 cm, P < .001; rigid, 1.7 cm, SD 0.9 cm, P < .003) compared with the no-brace condition, and no differences in vertical jump height were observed between the brace conditions (0.6 cm, SD 0.3, P = .3). There was a negative correlation between body fat percentage and vertical jump height (r = –0.075, P = .02). The Vertec device reliably measured vertical jump in all 3 conditions. The no-brace vertical ground reaction forces during the loading phase were significantly greater than brace conditions. Ankle range of motion was greatest in the no-brace condition. Conclusions: Results from this study suggests that high-performance athletes wearing ankle braces experience a significant decrease in vertical jump height independent of the type of ankle brace worn. Clinical Relevance: Sports physicians and health care providers caring for high-level athletes should counsel athletes on the trade-offs of wearing protective equipment in sport, as potential decreases in sports performance can lead to increased injury prevention. Level of Evidence: III.

Wash water is generated as a by-product of ready mixed concrete production. Reuse of the water as mixture water is limited, in practice, by the negative material performance impacts associated with the water chemistry and suspended solids (i.e. hydrating binder phases and very fine aggregate); the effects are intensified with increasing content of suspended solids and water age. A novel carbon dioxide treatment to allow the use of high solids wash water as mixture water was examined through mortar and concrete testing. An industrially sourced wash water with a specific gravity of over 1.20 was treated with CO2. Seven batches of concrete were produced and compared: a reference mixture at three different w/b, and four batches with a 6% reduction in cement where wash water was used as mixture water (diluted to a specific gravity of 1.08, comparing untreated versus CO2 treated conditions, aged either 1 day or 5 days). The treatment mineralized CO2 at 27% by weight of the cement in the solids and reduced or eliminated negative aspects associated with the untreated water (set acceleration, workability loss, strength reduction with water age). The CO2-treated solids displayed latent hydraulicity. The approach allows three waste streams (CO2, wash water and wash water solids) to be reused to produce more sustainable concrete.

This paper presents an experimentally validated modeling methodology for a new type of blower design known as volumetric resistance blower (VRB). It replaces the traditional centrifugal blower fan blades with a continuous porous medium disk and has been reported to be capable of providing a lower acoustic noise for the same output flow compared to a traditional blower. A three-dimensional transient numerical model of VRB is developed which incorporates the movement of a porous rotor using experimentally determined foam parameters to characterize the porous drag effect and a sliding mesh to simulate the rotation effect. The numerical results are validated with experimentally determined fan curve over broad range of operating conditions. The effect of the foam resistance parameters on the flow characteristics is investigated which serves the rationale for the optimization of these parameters. The model is used to study the sensitivity of the VRB performance to foam parameters using different types of commercially available open-cell reticulated foam.

The industrial injection of carbon dioxide into ready mixed concrete during mixing and batching can produce a measurable increase in hydration and a significant compressive strength increase. Physiochemical aspects of the mechanism were investigated through the analysis of a model tricalcium silicate system activated with a carbon dioxide addition immediately after hydration started. The attendant effects were examined through isothermal calorimetry, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). Carbonate reaction products around 70 nm were observed to have formed within 60 s of the CO2 gas injection. Within 10 min the carbonates have been covered by new hydration products. The initial product formed appears to be an amorphous or poorly crystalline calcium carbonate. The overall reaction over 24 h was the same for the hydrated and CO2-activated cases although the latter instance included the formation of carbonate reaction products.

Additions of carbon dioxide to hydrating concrete have been observed to result in performance benefits. In this study, oil-well cement (selected for its very low initial carbonate content) was hydr...

Highly luminescent gold clusters simultaneously synthesized and stabilized by protein molecules represent a remarkable category of nanoscale materials with promising applications in bionanotechnology as sensors. Nevertheless, the atomic structure and luminescence mechanism of these gold clusters are still unknown after several years of developments. Herein, we report findings on the structure, luminescence and biomolecular self-assembly of gold clusters stabilized by the large globular protein, bovine serum albumin. We highlight the surprising identification of interlocked gold-thiolate rings as the main gold structural unit. Importantly, such gold clusters are in a rigidified state within the protein scaffold, offering an explanation for their highly luminescent character. Combined free-standing cluster synthesis (without protecting protein scaffold) with rigidifying and un-rigidifying experiments, were designed to further verify the luminescence mechanism and gold atomic structure within the protein. Finally, the biomolecular self-assembly process of the protein-stabilized gold clusters was elucidated by time-dependent X-ray absorption spectroscopy measurements and density functional theory calculations.

Carbon dioxide was investigated for use as a beneficial admixture to concrete as it was truck mixed. The reaction between the CO2 and the hydrating cement creates finely distributed calcium carbonate reaction products that thereby influence the subsequent hydration. Comparisons of the fresh, hardened and durability properties were made between a reference concrete batch, a batch that contained a conventional accelerating admixture, and three batches subjected to a carbon dioxide addition. The optimum dose of carbon dioxide was found to reduce the time to initial set by 40% and increase the one and three day compressive strengths by 14% and 10% respectively. In comparison to the CO2 batch, the conventional accelerator provided greater reductions in set time but lower early strength. Concrete durability test results indicated that the carbon dioxide process did not compromise the expected durability performance of the treated concrete. Carbon dioxide is a viable admixture to improve concrete performance.

A novel carbon utilization trial produced carbon dioxide treated concrete blocks by adding carbon dioxide gas to the concrete during the mixing and forming stages of the block production. The gas was supplied at up to 1.5% by weight of cement. The carbon dioxide was absorbed into the concrete with an average efficiency of about 88% of the gas delivered. The carbon dioxide was shown to reduce the block compaction (and thereby the density) but increasing the mix water was an effective countermeasure. The carbonation process was shown to increase compressive strength (13–33% at ages from 7 to 56 days) and decrease absorption (by 18–36%). The CO2 upcycling reduced the carbon footprint of the blocks by 1.4% thereby demonstrating a simple approach to utilizing carbon dioxide to make useful construction materials.

We analyze recently-collected feather tissues from two species of seabirds, the sooty tern (Onychoprion fuscatus) and brown noddy (Anous stolidus), in three ocean regions (North Atlantic, North Pacific, South Pacific) with different human impacts. The species are similar morphologically and are similar in the trophic levels from which they feed within each location. In contrast, we detect reliable differences in trophic position amongst the regions. Trophic position appears to decline as the intensity of commercial fishing increases, and is at its lowest in the Caribbean. The spatial gradient in trophic position we document in these regions exceeds those detected over specimens from the last 130 years in the Hawaiian Islands. Modeling suggests that climate velocity and human impacts on fish populations strongly align with these differences.

Executive dysfunction, characterized by impaired decision making and impulsivity, has been suspected among individuals seeking treatment for hypersexuality, yet few studies have formally investigated this topic. The present study used the Iowa Gambling Task (IGT), an objective neuropsychological instrument, and the Barratt Impulsiveness Scale (BIS), a self-report measure, to assess decision-making characteristics and impulsivity in a sample of hypersexual men. Treatment-seeking males with clinically elevated scores on the Hypersexual Behavior Inventory (HBI-19) and who otherwise met criteria for hypersexuality completed the IGT and BIS. Results were compared to a control condition. The current analysis identified significant group differences on the IGT and the BIS. Hypersexual participants selected decks containing frequent loss penalties at a greater frequency than controls on the IGT and endorsed elevated levels of impulsivity on the BIS. The current results reflect non-normative responses on both meas...

Wildlife contaminant loads are often used to indicate ecosystem health, but their interpretation is complicated by the dynamics affecting the trophic transfer of toxins. Yet, coupled analyses of trophic position and contaminants may provide insights that help resolve the underlying signal of contaminants in ecosystems. Here, we analyze heavy metal concentrations and trophic positions for pelagic seabirds across time and space. We derive metal-specific trophic transfer coefficients from the literature and use them to interpret the changes in raw heavy metal concentrations in two settings: (i) for eight seabird species across a 125-year timeline in Hawaii, and (ii) for contemporary specimens of two tern species across three ocean basins. While previous studies report how trophic position varies in these two settings, here we investigate how trophic downgrading may affect the observed raw changes in contaminants. Using this approach, we find the highly-toxic metal elements (Hg, As, Pb) decline after 1980. However, several other metals (Cu, Mn, Mo, Cd, Fe) increase from 1990–2015. Though simultaneous biomagnification and trophic downgrading may obscure contaminant analyses across space and time, the trophic declines we observed (≤0.5 trophic level) are likely not sufficient to influence such comparisons. In addition, as extrapolating contaminant concentrations across broad ranges of trophic levels may be prone to large uncertainties, careful selection of the focal species for analysis is required. While high trophic level species, such as long-lived, fish-eating seabirds, are ideal for monitoring environmental contaminants across large spatial or time scales, lower trophic level species, like primary producers and consumers, may be more suitable for quantifying the concentrations of bio-available contaminants entering the marine ecosystem and the base of the marine food webs. Monitoring low and high trophic levels simultaneously may provide an integrated perspective that is needed to quantify the contaminants entering and bio-magnifying through marine ecosystems.

Vapor chamber technologies offer an attractive approach for passive cooling in portable electronic devices. Due to the market trends in device power consumption and thickness, vapor chamber effectiveness must be compared with alternative heat spreading materials at ultra-thin form factors and low heat dissipation rates. A test facility is developed to experimentally characterize performance and analyze the behavior of ultra-thin vapor chambers that must reject heat to the ambient via natural convection. The evaporator-side and ambient temperatures are measured directly; the condenser-side surface temperature distribution, which has critical ergonomics implications, is measured using an infrared camera calibrated pixel-by-pixel over the field of view and operating temperature range. The high thermal resistance imposed by natural convection in the vapor chamber heat dissipation pathway requires accurate prediction of the parasitic heat losses from the test facility using a combined experimental and numerical calibration procedure. Solid Metal heat spreaders of known thermal conductivity are first tested, and the temperature distribution is reproduced using a numerical model for conduction in the heat spreader and thermal insulation by iteratively adjusting the external boundary conditions. A regression expression for the heat loss is developed as a function of measured operating conditions using the numerical model. A sample vapor chamber is tested for heat inputs below 2.5 W. Performance metrics are developed to characterize heat spreader performance in terms of the effective thermal resistance and the condenser-side temperature uniformity. The study offers a rigorous approach for testing and analysis of new vapor chamber designs, with accurate characterization of their performance relative to other heat spreaders.Copyright © 2015 by ASME

We report element-specific X-ray spectroscopy results on the structure and bonding of Au24Pt, a thiolate-protected bimetallic nanocluster. Platinum L3-edge extended X-ray absorption fine-structure (EXAFS) data, in association with X-ray photoelectron spectroscopy (XPS) compositional analysis, was used to identify the location of the Pt dopant to be in the center of the icosahedron Au13 core. Comparison of Au24Pt with the structure of Au25 by gold L3-edge EXAFS clearly shows contraction of both metal–thiolate and metal–metal bond distances, caused by Pt doping. The doping effect on the electronic properties of Au24Pt was further evaluated by high-resolution Au 4f core-level XPS and ab initio calculations, which elucidate the importance of bimetallic (Pt–Au) bonding and bond contraction effects on the properties of Pt-doped thiolate-gold nanoclusters.

With the recent successful synthesis of an increasing number of atomically precise thiolate–gold nanoclusters (NCs), there are growing demands for a better understanding of their atomic structures and structure–property relationships in response to composition change. Herein, we present X-ray experimental results on structural and electronic properties of a recently synthesized gold–thiolate nanocluster, Au19(SR)13, in comparison with the structurally well-known Au25(SR)18 reference. The atomic structure of Au19(SR)13 was first probed with extended X-ray absorption fine structure (EXAFS). A multishell EXAFS fitting method (consisting of one Au–S and three Au–Au shells) allowed for a detailed structural comparison of the two nanoclusters, which revealed a sizable increase of the bond distances between the surface–surface and surface–staple Au atoms upon the decrease of Au atoms in the nanocluster. X-ray photoemission experiments and ab initio calculations further demonstrated the sensitive change of electr...

While recent advances in the synthesis and crystallography of gold–thiolate nanoclusters have led to enormous progress in understanding the structure and bonding of gold thiolate nanomaterials, the changes in structure experienced by these nanomaterials in different conditions, such as low temperature and solvation, is still largely lacking. Herein, we report a temperature- and solvation-dependent extended X-ray absorption fine structure (EXAFS) study of thiolate-protected Au25 nanoclusters. The structural changes experienced by Au25 in response to low temperature and different solvation environments are illustrated in great detail using a site-specific EXAFS fitting approach consisting of one Au–S and three Au–Au shells. EXAFS simulations as well as ab initio calculations of the local density of states are used to support the EXAFS analysis and correlate the structural characteristics of Au25 with its electronic properties. These experimental and theoretical studies point out the existence of the interpl...

Understanding the atomic structure and structure−property relationship of Au−thiolate clusters is essential for advancing their fundamental studies and applications. However, a precise determinatio...

Herein, we present the structural characterization of the core and surface of colloidally stable ultrathin bismuth sulfide (Bi(2)S(3)) nanowires using X-ray Absorption Spectroscopy (EXAFS and XANES), X-ray Photoelectron Spectroscopy (XPS), and Nuclear Magnetic Resonance (NMR). These three techniques allowed the conclusive structural characterization of the inorganic core as well as the coordination chemistry of the surface ligands of these structures, despite the absence of significant translational periodicity dictated by their ultrathin diameter (1.6 nm) and their polycrystallinity. The atomic structure of the inorganic core is analogous to bulk bismuthinite, but Bi atoms display a remarkably higher coordination number than in the bulk. This can be only explained by a model in which each bismuth atom at the surface (or in close proximity to it) is bound to at least one ligand at any time.

Understanding the site-specific and size-dependent structure and bonding properties of gold−thiolate nanoparticles is one of the most fundamental questions in nanoscience. The recent synthesis of compositionally precise Aum(SR)n nanoparticles offers a promising opportunity to explicitly elucidate the structure−property correlation of nanomaterials from site-specific and size-dependent perspectives. Herein, we report an X-ray absorption (gold L3-, sulfur K-, and L3,2-edge) and photoemission (gold 4f, sulfur 2p, and valence band) study of compositionally precise Aum(SR)n nanoparticles. An X-ray spectroscopy approach to deduce the atomic structure of Au144(SR)60 is first demonstrated. In conjunction with ab initio calculations, a high-precision, atomic-site-specific illustration of the bonding in Au144(SR)60 is achieved. By comparing size-varied samples [Au144(SR)60, Au38(SR)24, and Au25(SR)18], the size-dependent nature of bonding in gold−thiolate nanoparticles is revealed from both the sulfur and gold pers...

Impaired manual functioning often occurs when the hands are exposed to cold temperatures, but the underlying mechanism is not clearly understood. Tactile feedback is thought to provide important information during object manipulations in order to scale and regulate grip forces; however, topical anaesthetic-induced tactile sensation impairments may not realistically simulate the systemic neuromuscular impairment of the whole hand that could occur during cold temperature exposure. In two experiments, we studied the impact of (1) local hand cooling [thermoneutral finger skin temperature, cold (8 degrees C)] and (2) core body temperature (thermoneutral core body temperature, pre-heated by 0.5 degrees C, pre-cooled by 0.5 degrees C) with cold hands on manual dexterity and the ability to control and co-ordinate grip forces during a cyclical load-lifting task. In Experiment 1 (n = 10), hand cooling significantly decreased Purdue Pegboard performance (P = 0.002), while increasing grip force by approximately 5 N during the cyclical load-lifting task compared to thermoneutral (P = 0.037). The temporal co-ordination of grip and load forces was unaffected by hand cooling. In Experiment 2 (n = 11), pegboard performance was impaired following hand cooling (P0.001), and to a greater extent when the body was pre-cooled (p0.001). However, neither grip force (P = 0.99) nor the temporal co-ordination of grasping and lifting forces (P = 0.85) were affected by core body temperature. These data support the existence of a robust centrally controlled feedforward system able to anticipate the dynamics of manual manipulations and accordingly regulate the temporal co-ordination of fingertip forces during object manipulation. This centrally controlled mechanism appears to differ from the mechanisms governing other aspects of manual dexterity.

Destruction of the nasal septum and nasal bones by Mycobacterium leprae and subsequent infection is still seen regularly in leprosy endemic areas. The social stigma associated with this deformity is significant. Many different procedures have been developed to reconstruct the nose. Patients operated on at Anandaban Hospital and the Green Pastures Hospital and Rehabilitation Center between 1986 and 2001 were reviewed. There were 48 patients with an average age of 47 years. Five deformities were mild, 22 were moderate, 13 were severe, and eight were not graded. Bone grafting with nasolabial skin flaps was performed in 14 cases, bone grafting alone was performed in 10 cases, flaps alone were performed in seven cases, and cartilage grafting was performed in 10 cases. In three patients, a prosthesis was inserted, and in three patients a gull-wing forehead flap was performed. Overall, excellent or good cosmetic results were obtained in 83 percent of cases. Grafting with conchal cartilage was associated with the best cosmetic results and had minimal complications. Bone grafting with or without nasolabial flaps was associated with a 50 percent complication rate of infection or graft resorption. In mild to moderate deformities, cartilage grafting is recommended; for more severe deformities, bone grafting with bony fixation and skin flaps is recommended. Perioperative antibiotics must be used, and these procedures should be performed by an experienced surgeon. In very severe cases with skin deficiency, reconstruction with a forehead flap gives good results.

One hundred and fifty-six opponensplasties carried out on 115 patients at Anandaban Hospital between 1987 and 1997 were reviewed. In most cases a flexor digitalis superficialis opponensplasty was performed. The outcome was assessed by measuring the finger to which the thumb could obtain a pinch grip, the gap between the thumb and little metacarpophalangeal joints, and the satisfaction of the patient. The objective assessments demonstrated excellent or good results in 89%. Good or fair patient satisfaction was obtained in 93%. Early complications were seen in seven cases (4%). Objective measurements of outcome and patient satisfaction were not always in agreement, indicating that objective measures do not adequately assess the success of surgery from the patient’s perspective. We thus conclude that subjective measurements of results are an important measure of success and should be included in the evaluation of surgical results.

The design, construction, operation and validation of a wall-shear-stress sensor, and measurements obtained using this sensor in air flows downstream of partial blockages in a mini-channel are presented. The sensor consisted of a hot wire mounted over a small rectangular slot and operated using a constant-temperature anemometer. It was used to investigate flows similar to those within the mini-channels inside notebook computers. The overall goal of the present work was to develop a sensor suitable for measurements of the wall-shear stress in such flows, which can be used to validate corresponding numerical simulations, as the latter are known to be often surprisingly inaccurate. To this end, measurements of the wall-shear stress, and the corresponding statistical moments and power spectral densities, were obtained at different distances downstream of the partial blockage, with blockage ratios of 39.7, 59.2, and 76.3 %. The Reynolds number (based on average velocity and hydraulic diameter) ranged from 100 to 900. The results confirmed the presence of unsteadiness, separation, reattachment, and laminar-turbulent transition in the ostensibly laminar flow of air in mini-channels with partial blockages. The present results demonstrate why accurate numerical predictions of cooling air flows in laptop and notebook computers remain a challenging task.

The applications of lanthanide-doped upconversion nanocrystals in biological imaging, photonics, photovoltaics and therapeutics have fuelled a growing demand for rational control over the emission profiles of the nanocrystals. A common strategy for tuning upconversion luminescence is to control the doping concentration of lanthanide ions. However, the phenomenon of concentration quenching of the excited state at high doping levels poses a significant constraint. Thus, the lanthanide ions have to be stringently kept at relatively low concentrations to minimize luminescence quenching. Here we describe a new class of upconversion nanocrystals adopting an orthorhombic crystallographic structure in which the lanthanide ions are distributed in arrays of tetrad clusters. Importantly, this unique arrangement enables the preservation of excitation energy within the sublattice domain and effectively minimizes the migration of excitation energy to defects, even in stoichiometric compounds with a high Yb(3+) content (calculated as 98 mol%). This allows us to generate an unusual four-photon-promoted violet upconversion emission from Er(3+) with an intensity that is more than eight times higher than previously reported. Our results highlight that the approach to enhancing upconversion through energy clustering at the sublattice level may provide new opportunities for light-triggered biological reactions and photodynamic therapy.

This work presents a combined approach of kinetic control and thermodynamic selection for the synthesis of monodisperse 19 gold atom nanoclusters protected by thiolate groups. The step of kinetic control allows the formation of a proper size distribution of initial size-mixed Au(n)(SR)(m) nanoclusters following the reduction of a gold precursor. Unlike the synthesis of Au(25)(SR)(18) nanoclusters, which involves rapid reduction of the gold precursor by NaBH(4) followed by size focusing, the synthesis of 19-atom nanoclusters requires slow reduction effected by a weaker reducing agent, borane-tert-butylamine complex. The initially formed mixture of nanoclusters then undergoes size convergence into a monodisperse product by means of a prolonged aging process. The nanocluster formula was determined to be Au(19)(SC(2)H(4)Ph)(13). This work demonstrates the importance of both kinetic control of the initial size distribution of nanoclusters prior to size focusing and subsequent thermodynamic selection of stable nanoclusters as the final product.

We have probed both the local structure and the electronic properties of Na-containing type II Si clathrates by x-ray absorption spectroscopy. The near-edge region of the spectrum is particularly sensitive to the local structure surrounding the Na atom. Through experimental investigations of a series of eight samples with general formula ${\text{Na}}_{x}{\text{Si}}_{136}$, with $x$ ranging from $\ensuremath{\sim}0$ to 21.5, and simulation of extended x-ray absorption fine structure (EXAFS) and x-ray absorption near-edge structure spectra (XANES), we find that Na is primarily in the larger ${\text{Si}}_{28}$ cages at low loadings, and loss of the Na relative to full cage occupancy occurs preferentially from the smaller ${\text{Si}}_{20}$ cages. Our EXAFS results also show that Na is dynamically disordered in the ${\text{Si}}_{28}$ cages but less disordered at higher Na loadings. Local-orbital density of states calculations indicate that the Na in the ${\text{Si}}_{20}$ cage has a charge of $0.7{e}^{\ensuremath{-}}$ while Na in the ${\text{Si}}_{28}$ cages has a slightly higher (loading-dependent) charge ($0.72{e}^{\ensuremath{-}}$ to $0.8{e}^{\ensuremath{-}}$).

The surface structural characteristics and electronic behavior of three platinum nanoparticle (NP) samples prepared with tertiary amine (Pt-TA), primary amine (Pt-PA), and thiol (Pt-SR) molecules were studied using Pt 4f, 5d, and S 2p x-ray photoelectron spectroscopy (XPS), Pt L(3)-edge x-ray absorption spectroscopy (XAS), and theoretical projected local density of states (l-DOS) calculations. Transmission electron microscopy and XPS composition analysis indicated that the three NPs were all very small (1-2 nm), the NP size decreasing in the order of Pt-TA>Pt-PA approximately Pt-SR. All the three samples showed a positive Pt 4f binding energy (BE) shift relative to that of the bulk, in the order of bulk

The room temperature rate constant of the reaction F+N 3 →NF+N 2 has been determined by monitoring the time dependence of laser-induced fluorescence from the intermediate N 3 radicals in the presence of a large excess of F atoms. Experiments were performed with CF 4 , SF 5 , and F 2 as precursors of the F atoms. The results indicate that the F+N 3 rate constant is (5.8±0.6)×10 -11 cm 3 s -1 at 298 K