Abstract.We consider the problem of computing an optimal range assignment in a wireless network which allows a specified source station to perform a broadcast operation. In particular, we consider this problem as a special case of the following more general combinatorial optimization problem, called Minimum Energy Consumption Broadcast Subgraph (in short, MECBS): Given a weighted directed graph and a specified source node, find a minimum cost range assignment to the nodes, whose corresponding transmission graph contains a spanning tree rooted at the source node. We first prove that MECBS is not approximable within a constant factor (unless P=NP). We then consider the restriction of MECBS to wireless networks and we prove several positive and negative results, depending on the geometric space dimension and on the distance-power gradient. The main result is a polynomial-time approximation algorithm for the NP-hard case in which both the dimension and the gradient are equal to 2: This algorithm can be generalized to the case in which the gradient is greater than or equal to the dimension.

There is some concern regarding the amount of material thinning that occurs during the fabrication of custom-fabricated mouthguards. It is unclear if this thinning is merely a consequence of the fabrication process or related to other factors such as jaw size. Thus, the purpose of this study was to evaluate the contribution that various dimensional characteristics of the dental arch and the height of the stone model would have on mouthguard thinning. Fifteen subjects participated in this investigation. Alginate impressions from each subject were used to produce three replicas of the maxillary dentition with only the height of the base varying amongst them. The total height of the three models were 20, 25, and 30 mm. A single mouthguard was produced using each of the stone models. The material thickness of the mouthguard was assessed at the labial and occlusal surfaces. Additionally, the dimensions of the stone models were documented. Pearson product moment correlation coefficients were calculated to determine the linear relationship between material thickness and (i) the height of the stone models, (ii) the arch length and (iii) the area covered by the stone model. Statistical tests performed using the mean thickness values collected from the incisors and canines revealed a high negative correlation between the height of the stone model and material thickness (r = -0.82). In addition, a low to moderate positive linear correlation was noted between arch length and occlusal thickness at the molars (r = 0.57) and between the area of the stone model with the occlusal thickness (r = 0.49). The results of the present study indicate that the height of the model used to fabricate custom mouthguards should be kept as low as possible but still allow for the production of a properly fitting mouthguard.

Power is an important component of general health, fitness, and athletic performance. Traditional overload techniques require considerable time, intensity, and volume of training. Whole-body vibration (WBV) is a potentially less time-consuming method for increasing power performance than traditional training. However, the exact protocols that can maximize power output have not yet been identified. Eleven healthy men, aged 32.3 +/- 4.1 years, and 9 healthy women, aged 29.1 +/- 3.5 years, performed countermovement jumps (CMJs) of maximal volition to assess peak power pre and post (immediately and at 1, 5, and 10 minutes) randomized WBV stimuli set at different frequency (30, 35, 40, and 50 Hz), displacement (2-4 vs. 4-6 mm), and duration (30, 45, and 60 seconds) combinations. Repeated-measures analysis of variance on peak power normalized to initial power (nPP) revealed no significant effects attributable to duration of stimulus. However, high frequencies were more effective when combined with high displacements, and low frequencies were more effective in conjunction with low displacements (p < 0.05). Additionally, the greatest improvements in nPP occurred at 1 minute posttreatment, with significant improvements lasting through 5 minutes posttreatment (p < 0.05). Optimal acute effects can be attained using as little as 30 seconds of WBV, and they are highest from 1 to 5 minutes posttreatment. Additionally, high frequencies were most effective when applied in conjunction with high displacements, whereas low frequencies were most effective when applied in conjunction with low displacements.

The Bodyblade produces greater scapular activity than traditional resistance techniques.

The thermoforming process involves the heating of plastic sheets to a critical temperature followed by the shaping of the heated material into a three-dimensional structure. Given that custom-fabricated mouthguards are produced using the thermoforming process, the adaptation of plastic sheets to a stone model of the dentition is likely to be affected by the ability of the mouthguard material to be heated. The purpose of this study was to establish if material color affected the adaptation and fit of custom-made mouthguards. Twelve stone models were used in this investigation. Five mouthguards were produced using each model. These mouthguards were made using clear-, white-, black-, blue- and green-colored ethyl vinyl acetate. The force required to remove the various colored mouthguards from the corresponding stone models was determined using a strain gauge housed within a specially designed apparatus. Each of the mouthguards were tested three times at two different angles of pull -45 degrees and 90 degrees . Statistical tests performed using the average amount of force required for mouthguard removal revealed an angle by color interaction. Post hoc analyses revealed that the mean force required to remove the clear-colored mouthguards from their respective stone models was significantly less than the force required to pull away blue-, black- and green-colored mouthguards. This difference between clear- and dark-colored mouthguards was observed at both angles tested with the exception of the black mouthguard which differed from the clear-colored mouthguard only when removed at an angle of 90 degrees . The results of the present study indicate that by using dark-colored mouthguard material, one can achieve superior adaptation and thus produce a more firmly fitting mouthguard.

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The participants of this study were able to restrict flexion-extension motion equally well with thelog-roll maneuver as with the lift-and-slide technique. However, more research is needed to fully ascertain the effectiveness of spine-board transfer techniques.

Neurodegenerative disorders and diseases (NDDs) that are either chronically acquired or triggered by a singular detrimental event are a rapidly growing cause of disability and/or death. In recent times, there have been major advancements in our understanding of various neurodegenerative disease states that have revealed common pathologic features or mechanisms. The many mechanistic parallels discovered between various neurodegenerative diseases suggest that a single therapeutic approach may be used to treat multiple disease conditions. Of late, natural compounds and supplemental substances have become an increasingly attractive option to treat NDDs because there is growing evidence that these nutritional constituents have potential adjunctive therapeutic effects (be it protective or restorative) on various neurodegenerative diseases. Here we review relevant experimental and clinical data on supplemental substances (i.e., curcuminoids, rosmarinic acid, resveratrol, acetyl-L-carnitine, and ω-3 (n-3) polyunsaturated fatty acids) that have demonstrated encouraging therapeutic effects on chronic diseases, such as Alzheimer's disease and neurodegeneration resulting from acute adverse events, such as traumatic brain injury.