Ammonia borane (H₃N-BH₃, AB) is a lightweight material containing a high density of hydrogen (H₂) that can be readily liberated for use in fuel cell—powered applications. However, in the absence of a ...straightforward, efficient method for regenerating AB from dehydrogenated polymeric spent fuel, its full potential as a viable H₂ storage material will not be realized. We demonstrate that the spent fuel type derived from the removal of greater than two equivalents of H₂ per molecule of AB (i.e., polyborazylene, PB) can be converted back to AB nearly quantitatively by 24-hour treatment with hydrazine (N₂H₄) in liquid ammonia (NH₃) at 40°C in a sealed pressure vessel.
We developed an integrated chip for real-time amplification and detection of nucleic acid using pH-sensing complementary metal-oxide semiconductor (CMOS) technology. Here we show an ...amplification-coupled detection method for directly measuring released hydrogen ions during nucleotide incorporation rather than relying on indirect measurements such as fluorescent dyes. This is a label-free, non-optical, real-time method for detecting and quantifying target sequences by monitoring pH signatures of native amplification chemistries. The chip has ion-sensitive field effect transistor (ISFET) sensors, temperature sensors, resistive heating, signal processing and control circuitry all integrated to create a full system-on-chip platform. We evaluated the platform using two amplification strategies: PCR and isothermal amplification. Using this platform, we genotyped and discriminated unique single-nucleotide polymorphism (SNP) variants of the cytochrome P450 family from crude human saliva. We anticipate this semiconductor technology will enable the creation of devices for cost-effective, portable and scalable real-time nucleic acid analysis.
Going full circle: Ammonia borane is a potential H2‐releasing fuel. Polyborazylene, a form of the spent fuel, can be regenerated efficiently in a one‐pot process by the stepwise addition of ...appropriate digesting and reducing agents. A unique feature of this process is the formation of NH3, which is retained by some of the digested species.
Owens, SG, Garner III, JC, Loftin, JM, van Blerk, N, and Ermin, K. Changes in physical activity and fitness after 3 months of home Wii Fit™ use. J Strength Cond Res 25(11)3191–3197, 2011—The purpose ...of this study was to examine changes in physical activity and fitness variables in members of 8 volunteer families after 3 months of home use of the Wii Fit™ interactive video game. Pre and postintervention measurements were obtained from 21 subjects relative to physical activity (5 days of accelerometry), aerobic fitness (graded treadmill test), muscular fitness (push-ups), flexibility (sit-and-reach test), balance (composite equilibrium score), and body composition (body mass index and % body fat). Use characteristics of the Wii Fit™ device were also determined. A series of 2 (age group) × 2 (time) repeated measures analyses of variance were conducted to assess changes over time and between adults and children. Three months of home Wii Fit™ use revealed no significant age group × time interactions or main effects of group or time for daily physical activity, muscular fitness, flexibility, balance, or body composition. An age group × time interaction (p = 0.04) was observed in peak O2 (ml·kg·min) with children displaying a significant (p = 0.03) increase after 3 months of Wii Fit™ use, whereas adults showed no significant (p = 0.50) change. Daily Wii Fit™ use per household declined by 82% (p < 0.01) from 21.5 ± 9.0 min·d during the first 6 weeks to 3.9 ± 4.0 min·d during the second 6 weeks. Most measures of health-related fitness in this exploratory study remained unchanged after 3 months of home use of the popular Wii Fit™ whole-body movement interactive video game. Modest daily Wii Fit™ use may have provided insufficient stimulus for fitness changes.
The influence of firefighter boot type on balance Garner, John C.; Wade, Chip; Garten, Ryan ...
International journal of industrial ergonomics,
January 2013, 2013-1-00, 20130101, Letnik:
43, Številka:
1
Journal Article
Recenzirano
A firefighter's boots play a critical role in working effectiveness and personal safety. OSHA 1910.156 contains standards for personal protective equipment of fire brigades. Firefighters use either ...rubber or leather boots that meet these requirements. The purpose of the study was to examine the differences in balance in professional firefighters wearing rubber and leather boots when participating in a fire simulation activity. Twelve professional firefighters performed 2 sets of a three-minute simulated firefighter stair climb wearing a 50 lb weighted vest to simulate their typical personal protective equipment and two 5.68 kg weights on the shoulders to simulate the weight of a high-rise pack (hose bundle). On each condition day (leather, rubber) the firefighter conducted a balance assessment. Following the initial balance protocol, the firefighter conducted a Simulated Firefighter Stair Climb for 3 min at a rate of 60 steps per/min. At the completion of the stair climb, the firefighter repeated the balance procedure. Following a 3-minute rest period, the complete procedure (balance, stair climb) was repeated. A total of 3 balance procedures and 2 stair climbs were completed. Significant differences were found in sway velocity between the pre and post test measures and among the two different boots. These results suggest that the rubber boots elicit greater postural instability. These findings provide practical information on work practices and PPE usage decisions.
Industry standards dictate the protective variables of boots used by fire brigades, but do not consider the influence on gait and balance. This study provides evidence that the rubber boots used by firefighters may impair specific balance parameters which are critical for firefighter safety.
► Professional firefighting is a strenuous profession with relatively high rates of injury. ► The study compared balance in the two widely used firefighter boots. ► Rubber firefighter boots result in greater postural sway indicating balance decrements.
Muscle activity from the slipping leg have been previously used to analyze slip induced falls. However, the impact of casual alternative footwear on slipping leg muscle activity when exposed to ...slippery environments is still unknown. The purpose of the study was to analyze the impact of alternative footwear (crocs (CC) and flip-flops (FF)) compared to slip-resistant footwear (LT) on lower extremity muscle activity when exposed to dry gait (NG), unexpected (US), alert (AS), and expected slips (ES). Eighteen healthy males (age: 22.3 ± 2.2 years; height: 177.7 ± 6.9 cm; weight: 79.3 ± 7.6 kg) completed the study in a repeated measures design in three footwear sessions separated by 48 h. Electromyography (EMG) muscle activity from four muscles of the lead/slipping leg was measured during the stance phase of the gait-slip trials. A 3 (footwear) × 4 (gait-slip trials) repeated measures analysis of variance was used to analyze EMG dependent variables mean, peak, and percent of maximal voluntary contraction. Greater lower extremity muscle activation during the stance phase was seen in US and AS conditions compared to NG and ES. In addition, footwear differences were seen for the alternative footwear (CC and FF) during US and AS, while the low top slip resistant shoe had no differences across all gait trials, suggesting it as the most efficient footwear of choice, especially when maneuvering slippery flooring conditions, either with or without the knowledge of an impending slip.
Slips, trips and an induced loss of balance have been identified as the major causative factor for workplace injuries involving falls. Moreover, alternative footwear such has crocs and flip flops ...have been used in and around work places, especially with the usage of crocs in slip prone hospital settings.
The purpose of the study is to analyze the effects of alternative footwear crocs (CC), flip-flops (FF) and industry standard slip resistant shoes (LT) on heel dynamics during slip events.
Eighteen healthy male participants following a repeated measures design for each footwear condition, were tested for heel kinematics during normal dry surface gait (NG); unexpected slip (US), alert slip (AS) and expected slip (ES). A 3×4 repeated measures ANOVA was used to analyze the dependent slip parameters (heel slip distance-HSD & mean heel slip velocity-MHSV) at p = 0.05.
Significant interactions between footwear and gait trials were found for HSD & MHSV, with significantly greater slip parameters exhibited by CC & FF compared to LT during US.
Alternative footwear (CC & FF) demonstrated greater slips, but were limited to slip events that were unexpected. With the knowledge and anticipation of slippery flooring conditions, participants were able to lower the slip parameters by kinematically modifying heel contact dynamics. The LT had significantly lower slip parameters and maintained a normal gait pattern for all slip trials, and demonstrates to be the choice of footwear for maneuvering slippery flooring conditions; while alternative footwear combined with unexpected slip events contributed to potentially hazardous and hazardous slips.
Alternative footwear such as crocs are widely used in hospitals which are slip prone environments. This study provides evidence that these alternative footwear may predispose to hazardous slips and recommends the use of slip resistant footwear or slip resistant modifications to alternative footwear under known or unknown slippery conditions.
•Crocs and flip flops demonstrated greater slip distance and velocity in slip trials.•The slip parameters of alternative footwear were greater in unexpected slips.•Knowledge and anticipation of slippery environment lowered slip parameters.•Low top slip resistant shoe had better performance in all slip trials.
Single-limb balance training is integral to preventing and rehabilitating lower extremity injuries. Previous investigations have shown that when using instability devices, differences may or may not ...exist in the postural sway parameters during use, depending on the specific devices being assessed. Thus, this investigation sought to examine the differences between a commonly used foam pad and a novel instability device (block) in postural sway measures. Twenty-two healthy individuals with no history of lower extremity injury or neurological disorders participated in this investigation. The participants performed three single-limb static balance exercises on a force platform sampling at 120 Hz. Each condition contained three 10-s trials separated by thirty seconds. The mean CoP values of the three trials in each condition were then compared using a within-subjects repeated-measures analysis of variance. Statistically significant differences were seen in the sway area between conditions (p = 0.009), the CoP path length (p = 0.007), the peak medial–lateral CoP displacement (p = 0.004), and the average sway velocity (p = 0.007). All variables displayed similar trends whereby the control condition showed significantly lower values than both instability devices, with no differences between devices. This investigation provides supporting evidence that different instability devices may deliver similar changes to postural sway parameters compared to control conditions. The novel block instability device used in this investigation may be used similarly to the traditional foam pad in prevention and rehabilitation settings based on the absence of differences between the two devices.
Abstract Objective Studies have looked at the individual associations of sensory impairment on balance, but no population-based studies have examined their combined association on balance and ...difficulty with falls. Thus, the purpose of this study was to examine both the independent associations and combined associations of visual impairment, peripheral neuropathy, and self-reported hearing loss with the odds of reporting difficulty with falls and functional balance. Methods Data from the 2003–2004 National Health and Nutrition Examination Survey were used. Vision and peripheral neuropathy were objectively measured, and hearing was self-reported. Balance testing consisted of a modified Romberg test. After exclusions, 1662 (40–85 years of age) participants provided complete data on the study variables. Results Sensory impairment was associated with perceived difficulty of falls and functional balance. Participants who presented a single sensory impairment had 29% reduced odds of having functional balance (95% CI = 0.54–0.93, p = 0.01) and increased odds of reporting difficulty with falls by 61% (95% CI = 0.99–2.60, p = 0.05). Moreover, our multisensory models showed some evidence of a dose–response relationship, in that sensory impairment of multiple sensory systems was associated with worse balance (OR = 0.59, CI = 0.35–1.00, p = 0.05) and perceived difficulty of falls (OR = 5.02, 95% CI = 1.99–12.66, p = 0.002) when compared to those with less sensory impairment. Conclusion Multiple sensory impairment is associated with significantly higher odds of both reporting difficulty with falls and balance dysfunction, which may lead to a subsequent fall, ultimately compromising the individual's health.
Postural stability has been shown to be impacted by footwear and task performed. This study analysed the impact of two military footwear, standard boot (STB) and minimalist boot (MTB) on postural ...stability, before (PRE) and after (POST) a load carriage task. Sixteen participants were tested for postural stability using sensory organisation and motor control tests on Neurocom Equitest™. Postural sway, equilibrium scores and postural latencies were analysed using a two-factor repeated measures ANOVA: boot type (STB-MTB) × time (PRE-POST) load carriage task. Significantly greater postural sway variables, lower balance scores and slower postural latencies were seen in STB and POST load carriage conditions (p < .05). The results suggest that MTB exhibited greater balance compared to STB in balance conditions that rely on somatosensory feedback and that balance is lowered after a load carriage task. Decrements in postural stability could be attributed to boot design characteristics and muscular exertion due to the load carriage task.
Practitioner Summary: Maintaining optimal postural stability is crucial in military. Impact of military footwear types and load carriage task on postural stability are addressed. Findings provide footwear design and physical exertion implications on postural stability leading to potential interventions that reduce postural stability decrements; thereby, reducing potential falls and fall related injuries.
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