1,195 research outputs found

    Resonant plasma excitation by single-cycle THz pulses

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    In this paper, an alternative perspective for the generation of millimetric high-gradient resonant plasma waves is discussed. This method is based on the plasma-wave excitation by energetic single-cycle THz pulses whose temporal length is comparable to the plasma wavelength. The excitation regime discussed in this paper is the quasi-nonlinear regime that can be achieved when the normalized vector potential of the driving THz pulse is on the order of unity. To investigate this regime and determine the strength of the excited electric elds, a Particle-In-Cell (PIC) code has been used. It has been found that by exploiting THz pulses with characteristics currently available in laboratory, longitudinal electron plasma waves with electric gradients up to hundreds MV/m can be obtained. The mm-size nature of the resonant plasma wave can be of great utility for an acceleration scheme in which high-brightness electron bunches are injected into the wave to undergo a strong acceleration. The long-size nature of the acceleration bucket with respect to the short length of the electron bunches can be handled in a more robust manner in comparison with the case when micrometric waves are employed

    The sutures in dentistry

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    In oral surgery, the last phase of a surgical operation is represented by the tissues suture, that allows the wound lips edges approximation and their stabilization, to promote haemostasis, to avoid the alimentary residues accumulation on the incision line and allow the first intention healing. A good suture avoids that the displacing forces generated by the muscular insertions, functional movements and by the external agents destabilize or cause the surgical wound deiscence. The purpose of this study was to re-examine the suture threads characteristics, properties and biological interactions evaluating the different studies published in literature results and conclusions. In conclusion, the authors recommended the use of the different suture threads on the dependence of the oral surgery operation type that must be performed, of the patient compliance and of the various suture materials physical and biocompatibility characteristics

    The Effect of Omega-3 Supplementation on Exercise-Induced Muscle Damage

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    Exercise-induced muscle damage (EIMD) results in transient muscle inflammation, strength loss, muscle soreness (Damas et al., 2016) and can result in subsequent exercise avoidance. Omega-3 (n-3) supplementation has been proposed to minimise EIMD via its anti-inflammatory properties (Jakeman et al., 2017), however its action remains unclear. We aimed to examine the effects of n-3 supplementation on exercise-induced inflammatory response following muscle-damaging exercise. Physically active, healthy Caucasian males (n = 14, 25.07 ± 4.05 years) provided written informed consent, then were single-blind randomised to either receive 3 g/day n-3 supplementation (N-3, n = 7) or placebo (PLA, n = 7). Following 4 weeks n-3 supplementation, a downhill running protocol (60 minutes at 65% V̇O2max, -10% gradient) was performed. Before supplementation (baseline), prior to EIMD, immediately after EIMD, and at 24, 48, and 72 hours post-EIMD, venous plasma was collected for creatine kinase (CK), interleukin (IL)-6 and tumour necrosis factor (TNF)-a, and maximal voluntary isometric contraction (MVIC), peak power (PP) and perceived muscle soreness were also quantified. Results are presented here as ‘median and interquartile range’ for CK, IL-6, TNF-a and perceived muscle soreness, and as ‘mean ± SD’ for MVIC and PP. Significant difference in CK activity was found between N-3 and PLA (p = 0.048) at 24 h post-EIMD, with PLA showing a larger increase in serum CK (baseline- vs 24h post-EIMD) compared to N-3 (677.4% vs 459.6%, respectively). PLA showed a larger increase in plasma IL-6 compared to N-3 immediately post-EIMD (143.9% vs 131.1%, respectively), however, there was no significant difference between groups at any time point (p > 0.05). TNF-a showed a smaller increase for the N-3 group compared to the PLA, again, there were no significant differences between groups at any time point (p > 0.05). Significant difference in muscle soreness was found between N-3 and PLA at 24 h post-EIMD (p = 0.034), with PLA showing a higher muscle soreness compared to N-3. A significant main effect for time was observed for MVIC with both groups showing a significant reduction in leg strength immediately post-EIMD. However, there were no significant differences between groups (p = 0.26) nor any group by time interactions (p = 0.90). A significant main effect for time was observed for PP, again, with PLA showing a larger reduction in PP at 24 h post-EIMD (pre- vs 24 h post-EIMD) compared to the N-3 (>96.6% vs N-3). However, there were no significant differences between groups (p = 0.31) nor any group by time interactions (p = 0.51). N-3 supplementation may attenuate EIMD, however, n-3 supplementation had no impact on muscle function nor power output. Even though we recorded some reduction in the inflammatory markers for the N-3 group, there was no statistically significant decrease to allow us to draw any definitive conclusions about the n-3 supplementation on exercise-induced muscle inflammation. Future studies might compare the dosage and duration of n-3 supplementation on muscle function or examine the effect of n-3 supplementation on EIMD during ageing-associated muscle function loss, where increased basal inflammation is seen

    The biology and treatment of acute long-bones diaphyseal fractures: Overview of the current options for bone healing enhancement

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    Diaphyseal fractures represent a complex biological entity that could often end into impaired bone-healing, with delayed union and non-union occurring up to 10% of cases. The role of the modern orthopaedic surgeon is to optimize the fracture healing environment, recognize and eliminate possible interfering factors, and choose the best suited surgical fixation technique. The impaired reparative process after surgical intervention can be modulated with different surgical techniques, such as dynamization or exchange nailing after failed intramedullary nailing. Moreover, the mechanical stability of a nail can be improved through augmentation plating, bone grafting or external fixation techniques with satisfactory results. According to the “diamond concept”, local therapies, such as osteoconductive scaffolds, bone growth factors, and osteogenic cells can be successfully applied in “polytherapy” for the enhancement of delayed union and non-union of long bones diaphyseal fractures. Moreover, systemic anti-osteoporosis anabolic drugs, such as teriparatide, have been proposed as off-label treatment for bone healing enhancement both in fresh complex shaft fractures and impaired unions, especially for fragility fractures. The article aims to review the biological and mechanical principles of failed reparative osteogenesis of diaphyseal fractures after surgical treatment. Moreover, the evidence about the modern non-surgical and pharmacological options for bone healing enhancement will discussed

    The Potential of Omega-3 Supplementation to Reduce Muscle-Inflammation after Muscle-Damaging Exercise

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    Muscle Damaging exercise (EIMD) induces inflammation and relates to strength loss, muscle-soreness and impaired recovery. Overall, this means a performance impairment which might be relevant for those who engages in competitions or strenuous physical activities. It remains unclear whether Omega-3 fatty acids (O-3) supplementation blunts the exercise-induced inflammation associated with EIMD and therefore prevents performance impairment. PURPOSE: Following a three-week supplementation with O-3, indirect markers of muscle damage were examined after a bout of EIMD to determine if supplementation had any beneficial effect in maintaining leg-strength levels. METHODS: Eight healthy, recreationally active caucasian males (28.13 ± 3.4 yr) were randomly allocated to a supplementation group (SUP, n = 4) to receive 2.85g/day O-3 supplementation or a control group (CON, n = 4) for three weeks. Following supplementation, participants performed a bout of EIMD, which consisted of performing 10 sets of 15 repetitions of leg extension at a self-assessed intensity of 7/10 on the Rate of Perceived Exertion scale. Creatine Kinase (CK) from venous blood samples, isometric right-leg strength, squat-jump test and perceived soreness were determined, as indirect markers of muscle-damage at Baseline, immediately after EIMD (POST) and 48 hours after EIMD to coincide with the delayed muscle inflammatory response. RESULTS: No statistically significant differences were found between Baseline and POST. There was a trend for smaller increase of CK levels (pre vs 48-h post EIMD) on the SUP group (38.8% increase) compared with the CON group (105.6% increase; P = 0.051). There was no significant effect (baseline vs. 48-h post EIMD) on muscle strength between SUP and CON group (P > 0.05), however, CON showed a larger decrease in strength compared to SUP (> 6.3% vs SUP). No differences in jump height were found between SUP and CON (P > 0.05). There was no significant difference in muscle soreness at 48-h post EIMD between SUP and CON group (P = 0.171). CONCLUSION: Three weeks of O-3 supplementation might decrease exercise-induced muscle inflammation after eccentric exercise. The lack of statistical significance may be adduced to the limitations of the study design and sample size. Supplementation with O-3 can be beneficial in athletes undergoing heavy exercise regimes and in sedentary individuals restarting physical activity, decreasing the exercise related muscle inflammation. The encouraging results from this pilot study have led to designing further work related to this topic

    The effect of Omega-3 polyunsaturated fatty acid supplementation on exercise-induced muscle damage

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    Background Exercise-induced muscle damage (EIMD) results in transient muscle inflammation, strength loss, muscle soreness and may cause subsequent exercise avoidance. Omega-3 (n-3) supplementation may minimise EIMD via its anti-inflammatory properties, however, its efficacy remains unclear. Methods Healthy males (n = 14, 25.07 ± 4.05 years) were randomised to 3 g/day n-3 supplementation (N-3, n = 7) or placebo (PLA, n = 7). Following 4 weeks supplementation, a downhill running protocol (60 min, 65% V̇O2max, − 10% gradient) was performed. Creatine kinase (CK), interleukin (IL)-6 and tumour necrosis factor (TNF)-α, perceived muscle soreness, maximal voluntary isometric contraction (MVIC) and peak power were quantified pre, post, and 24, 48 and 72 h post-EIMD. Results Muscle soreness was significantly lower in N-3 vs PLA group at 24 h post-EIMD (p = 0.034). IL-6 was increased in PLA (p = 0.009) but not in N-3 (p = 0.434) following EIMD, however, no significant differences were noted between groups. Peak power was significantly suppressed in PLA relative to pre-EIMD but not in N-3 group at 24 h post-EIMD. However, no significant difference in peak power output was observed between groups. MVIC, CK and TNF-α were altered by EIMD but did not differ between groups. Conclusion N-3 supplementation for 4 weeks may successfully attenuate minor aspects of EIMD. Whilst not improving performance, these findings may have relevance to soreness-associated exercise avoidance

    3D surface acquisition systems and their applications to facial anatomy : let’s make a point

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    In the last decades 3D optical devices have gained a primary role in facial anthropometry, where they find several applications from the anatomical research to clinics and surgery. With time the number of articles focusing on 3D surface analysis has raised, as well as validation studies which aim at verifying the reliability of different devices and methods of acquisition in comparison with other methods or direct anthropometry. This review aims at making a point in the field of 3D surface acquisition systems, describing the most used types of available devices and comparing the relevant outcomes in acquiring 3D facial models. Results show that currently stereophotogrammetric devices represent the gold standard, further improved by the diffusion of portable models. Caution should be given to the use of low-cost devices, more and more frequently described by literature, as often they do not meet the basic criteria for being applied to the anatomical study of face
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