Search

During elite-level hammer throws, the vertical displacement of the centre of mass (COM) of the thrower and hammer are approximately 180° out of phase (the hammer's COM is at its high point when the thrower's COM is at its low point, and vice versa) prior to the hammer's release. This out-of-phase coordination pattern contributes to the velocity of the hammer, which ultimately contributes to the distance thrown. Several drills are used to improve coordination between the thrower's and hammer's COM, but it is not currently known if the out-of-phase pattern is present during these drills. This study examined the relative phase between the COM of the hammer and thrower during two different rotational drills: The Double Hammer Head and Single Arm drills. Using a 12-camera motion analysis system, COM kinematics for both the hammer and thrower were examined for seven NCAA Division I throwers during the two drills. Contrary to their purported purpose, the phase angles between thrower's and hammer's COM were significantly different from 180° during both drills. Further research should be conducted to examine the mechanical factors of hammer throwing drills, as well as the effect such drills have when implemented within training programs. [ABSTRACT FROM AUTHOR]

Abstract Background The growing concern for player safety in rugby has led to an increased focus on head impacts. Previous laboratory studies have shown that rugby headgear significantly reduces peak linear and rotational accelerations compared to no headgear. However, these metrics may have limited relevance in assessing the effectiveness of headgear in preventing strain-based brain injuries like concussions. This study used an instantaneous deep-learning brain injury model to quantify regional brain strain mitigation of rugby headgear during drop tests. Tests were conducted on flat and angled impact surfaces across different heights, using a Hybrid III headform and neck. Results Headgear presence generally reduced the peak rotational velocities, with some headgear outperforming others. However, the effect on peak regional brain strains was less consistent. Of the 5 headgear tested, only the newer models that use open cell foams at densities above 45 kg/m3 consistently reduced the peak strain in the cerebrum, corpus callosum, and brainstem. The 3 conventional headgear that use closed cell foams at or below 45 kg/m3 showed no consistent reduction in the peak strain in the cerebrum, corpus callosum, and brainstem. Conclusions The presence of rugby headgear may be able to reduce the severity of head impact exposure during rugby. However, to understand how these findings relate to brain strain mitigation in the field, further investigation into the relationship between the impact conditions in this study and those encountered during actual gameplay is necessary.

Background: The growing concern for player safety in rugby has led to an increased focus on head impacts. Previous laboratory studies have shown that rugby headgear significantly reduces peak linear and rotational accelerations compared to no headgear. However, these metrics may have limited relevance in assessing the effectiveness of headgear in preventing strain-based brain injuries like concussions. This study used an instantaneous deep-learning brain injury model to quantify regional brain strain mitigation of rugby headgear during drop tests. Tests were conducted on flat and angled impact surfaces across different heights, using a Hybrid III headform and neck. Results: Headgear presence generally reduced the peak rotational velocities, with some headgear outperforming others. However, the effect on peak regional brain strains was less consistent. Of the 5 headgear tested, only the newer models that use open cell foams at densities above 45 kg/m3 consistently reduced the peak strain in the cerebrum, corpus callosum, and brainstem. The 3 conventional headgear that use closed cell foams at or below 45 kg/m3 showed no consistent reduction in the peak strain in the cerebrum, corpus callosum, and brainstem. Conclusions: The presence of rugby headgear may be able to reduce the severity of head impact exposure during rugby. However, to understand how these findings relate to brain strain mitigation in the field, further investigation into the relationship between the impact conditions in this study and those encountered during actual gameplay is necessary. [ABSTRACT FROM AUTHOR]

Background: Hyperthyroidism in humans is associated with a hypercoagulable state and an increased risk of thromboembolism. Objective: To evaluate hemostatic variables in hyperthyroid and euthyroid cats with the hypothesis that hyperthyroid cats will have evidence of altered hemostasis consistent with a potential hypercoagulable state. Animals: Client‐owned hyperthyroid (n = 16) and euthyroid (n = 15) cats over 8 years of age. Methods: Prospective observational study. Hyperthyroid and euthyroid cats were enrolled. Rotational thromboelastometry (ROTEM), whole‐blood platelet impedance aggregometry (WBPIA) and a point‐of‐care viscoelastic coagulation monitor (VCM‐Vet) were performed immediately after minimally traumatic venipuncture under sedation. Results: Hyperthyroid cats had significantly higher values for variables as assessed by VCM‐Vet: A10 (34 [17‐47] vs 25 [17‐38], P =.003); A20 (39.5 [23‐55] vs 31 [21‐45], P =.003); and MCF (41 [24‐58] vs 35 [22‐49], P =.03). Hyperthyroid cats had significantly different values versus the euthyroid cohort as assessed by different ROTEM channels: increased A10, INTEM (61.5 [39‐75] vs 54 [23‐66], P =.007) and FIBTEM (18 [10‐35] vs 13 [2‐27], P =.01); increased A20, INTEM (68 [45‐78] vs 61 [30‐70], P =.006) and FIBTEM (17 [10‐34] vs 11 [2‐25], P =.002); increased MCF, EXTEM (72 [65‐81] vs 69 [34‐78], P =.04), INTEM (70 [45‐85] vs 62 [35‐71], P =.01) and FIBTEM (18 [13‐37] vs 14 [3‐27], P =.02); increased alpha angle, EXTEM (80 [68‐85] vs 76 [41‐84], P =.01); shortened CT, EXTEM (52.5 [29‐73] vs 60 [52‐92], P =.003) and FIBTEM (52.5 [16‐75] vs 65 [53‐165], P =.001); and decreased ML, FIBTEM (20 [1‐36] vs 33 [19‐59], P <.001). No significant differences were found with WBPIA. Conclusions and Clinical Importance: The hyperthyroid cats in this study had evidence of altered hemostasis as assessed by 2 viscoelastic methodologies, and characterized by increased clot amplitude, firmness, and faster coagulation times vs euthyroid controls. [ABSTRACT FROM AUTHOR]

Wood is a preferred material for constructing staircases due to its appealing aesthetic features. The use of wood, especially hardwoods such as red oak (Quercus rubra), white oak (Quercus alba), yellow poplar (Liriodendron tulipifera), and hard maple (Acer saccharum), has been the main construction material for staircases over the years. Staircase designs have evolved because of the flexibility of wood and working with specialized manufacturing machinery. A stair guard system connection must be designed to resist rotational and translational movements whenever a force is applied to the handrail. The demand for structural design values in wooden stair guards has been steadily increasing, driven by the needs of engineers, designers, builders, and end-users alike. This paper presents experimental data for four stair guard connections (post-to-rail, infill-to-footing, infill-to-rail, and rail-to-rail) encountered in a hardwood stairway handrail guard system. The data generated from this research could be useful for modeling the structural behavior of the connections.

Wood is a preferred material for constructing staircases due to its appealing aesthetic features. The use of wood, especially hardwoods such as red oak (Quercus rubra), white oak (Quercus alba), yellow poplar (Liriodendron tulipifera), and hard maple (Acer saccharum), has been the main construction material for staircases over the years. Staircase designs have evolved because of the flexibility of wood and working with specialized manufacturing machinery. A stair guard system connection must be designed to resist rotational and translational movements whenever a force is applied to the handrail. The demand for structural design values in wooden stair guards has been steadily increasing, driven by the needs of engineers, designers, builders, and end-users alike. This paper presents experimental data for four stair guard connections (post-to-rail, infill-to-footing, infill-to-rail, and rail-to-rail) encountered in a hardwood stairway handrail guard system. The data generated from this research could be useful for modeling the structural behavior of the connections. [ABSTRACT FROM AUTHOR]

Purpose: To compare the outcomes of pterygium surgery by using an inferior rotational autograft and a conventional superior conjunctival autograft. Methods: This was a prospective interventional comparative study of 85 eyes of patients who were divided into two groups of 45 and 40. Standard techniques of both procedures were performed by a single surgeon. Astigmatism, recurrence rates, time taken, and other complications were compared. Results: All the subjects were in the age group 53 ± 7.56 (40–74) years. Demographic data and type of pterygium were comparable in the two groups. In the rotational group, the preoperative astigmatism was − 2.14 ± 1.36 D, which decreased in 1 week to 1.42 ± 1.11 D, in 1 month to − 1.13 ± 0.99 D, in 3 months to 0.91 ± 0.72 D, and in 6 months to 0.81 ± 0.85 D (P < 0.05 each). Preoperative astigmatism in the conventional group was − 2.63 ± 1.47 D, which decreased to − 1.43 ± 1.04 D in 1 week, −1.18 ± 0.85 D in 1 month, −1.07 ± 0.81 D in 3 months, and − 1.01 ± 0.78 D in 6 months (P < 0.05 each). There was no significant difference between the groups in terms of astigmatism at any follow-up visit (P < 0.05). Complications like dellen, graft edema, and superficial vascularization were seen in both groups. The rotational group had one recurrence (2.86%). No recurrence was noted in the conventional group. None of the complication rates was significantly different between the two groups (P < 0.05). Conclusion: Inferior rotational conjunctival autografting is a good technique for management of pterygium. It has a profile similar to that of conventional conjunctival autograft. [ABSTRACT FROM AUTHOR]

Background: Securing airway is a vital skill for anaesthesiologists. Difficulty in securing airway can lead to catastrophic results. The cuffed endotracheal tube is considered as gold standard for providing a safe airway. Laryngoscopy and endotracheal intubation produce reflex sympathoadrenal stimulation. The supraglottic airway device is a novel equipment that fills the gap in airway management between tracheal intubation and use of face mask. I-gel (Intersurgical Ltd., Wokingham, UK) is a relatively new supraglottic airway device with a noninflatable cuff, made up of soft gel like, transparent thermoplastic elastomer. Aim and objectives: To compare standard, reverse and rotational techniques of i-gel placement in terms of insertion characteristics and success rate. Materials and Methods: A randomized prospective study, was undertaken at Government Dharmapuri Medical College and Hospital, Dharmapuri during the academic year from 2020 to October 2022. Ninety patients (N=90), scheduled for various elective surgical procedures undergoing general anaesthesia belonging to ASA class I and II were included in the study. The participants were divided into 3 groups of 30 participants based on the techniques used for i-gel insertion. Results: There was no statistically significant difference in the age, ASA grading, Mallampatti class between the 3 groups. There was no statistically significant difference in the ease of insertion between the groups. The median attempts for insertion in all three groups was 1 attempt. Chin lift manoeuvre had to be performed in 2 participants in the standard insertion group. The mean time taken for insertion (in seconds) was 20.33 ± 4.05 in standard technique group, 19.47 ± 4.67 in reverse technique group and 19.67 ± 4.26 in rotational technique group and the mean difference was not statistically significant. There was no significant difference in the mean leak pressure across the groups. Maximum number (N=7) complications was seen in standard technique group. There was no significant difference in heart rate measured at 1 min, 3min and 5min across the group. There was significant difference in MAP at 1min (p=0.01), 3min (p=0.001) and 5 min (p=0.062) across the groups with highest mean MAP measured in standard technique group. Conclusion: The three insertion techniques are suitable for routine use in maintaining anaesthesia in spontaneously breathing patients under general anaesthesia with normal airways. By all methods I-Gel appear to be effective in providing a clinically patent airway and have a high rate of insertion success, no hemodynamic changes, and low morbidity. [ABSTRACT FROM AUTHOR]

AimsPersistent atrial fibrillation (AF) has been explained by multiple mechanisms which, while they conflict, all agree that more disorganized AF is more difficult to treat than organized AF. We hypothesized that persistent AF consists of interacting organized areas which may enlarge, shrink or coalesce, and that patients whose AF areas enlarge by ablation are more likely to respond to therapy.Methods and resultsWe mapped vectorial propagation in persistent AF using wavefront fields (WFF), constructed from raw unipolar electrograms at 64-pole basket catheters, during ablation until termination (Group 1, N = 20 patients) or cardioversion (Group 2, N = 20 patients). Wavefront field mapping of patients (age 61.1 ± 13.2 years, left atrium 47.1 ± 6.9 mm) at baseline showed 4.6 ± 1.0 organized areas, each separated by disorganization. Ablation of sites that led to termination controlled larger organized area than competing sites (44.1 ± 11.1% vs. 22.4 ± 7.0%, P

Due to their lack of pollution and long replacement cycles, piezoelectric energy harvesters have gained increasing attention as emerging power generation devices. However, achieving effective energy harvesting in ultra-low-frequency (<1 Hz) rotational environments remains a challenge. Therefore, a novel rotational energy harvester (REH) with a double-frequency up-conversion mechanism was proposed in this study. It consisted of a hollow cylindrical shell with multiple piezoelectric beams and a ring-shaped slider with multiple paddles. During operation, the relative rotation between the slider and the shell induced the paddles on the slider to strike the piezoelectric beams inside the shell, thereby causing the piezoelectric beams to undergo self-excited oscillation and converting mechanical energy into electrical energy through the piezoelectric effect. Additionally, by adjusting the number of paddles and piezoelectric beams, the frequency of the piezoelectric beam struck by the paddles within one rotation cycle could be increased, further enhancing the output performance of the REH. To validate the output performance of the proposed REH, a prototype was fabricated, and the relationship between the device's output performance and parameters such as the number of paddles, system rotation speed, and device installation eccentricity was studied. The results showed that the designed REH achieved a single piezoelectric beam output power of up to 2.268 mW, while the REH with three piezoelectric beams reached an output power of 5.392 mW, with a high power density of 4.02 μW/(cm3 Hz) under a rotational excitation of 0.42 Hz, demonstrating excellent energy-harvesting characteristics. [ABSTRACT FROM AUTHOR]

The article is about the analysis on waves through piezoelectric semiconductor solid rotating with fix angular frequency. The theory of non-local elasticity is assumed, in which the stress defined at some specific point is a function of strain at all neighboring points. Selected medium is n-type semiconductor with piezoelectric nature. As per the theory of thermo-elasticity, elastic distortion results in propagation of thermal wave conducting through the medium, encountered by classical heat conduction equation. We derived a relation for secular equation for reflected waves, originated because of bouncing back of incident wave from the surface of the media. The study indicates four reflected waves with positive projection and one with vibrational model having zero wave number. All the waves produced are coupled waves and quasi in nature. The analytical results obtained are computed graphically for a ZnO material with piezoelectric properties. The effect of rotational, non-local and steady carrier density parameters on the amplitude ratios of waves are study graphically. The current study provides a new thought for the scholars in the domain of piezoelectric semiconductors. [ABSTRACT FROM AUTHOR]

Abstract Background To assess the immediate effect and factors affecting the efficacy of rotational thrombectomy (RT) in patients with thrombus-containing lower-limb ischaemic lesions. Methods Patients were retrospectively divided into two groups: RT and RT+ CDT (Catheter-directed thrombolysis). The RT group included patients in whom intraoperative thrombus aspiration was successful, while the RT + CDT group included patients in whom intraoperative thrombus aspiration was less effective and remedial CDT treatment was used. The primary outcome was the immediate effect of RT on thrombus-containing lower-limb ischaemic lesions. Results From May 2015 to July 2021, 170 patients (113 men, 57 women; mean age, 74.0 years) with thrombus-containing lower-limb ischaemic lesions were treated in our centre. Of these patients, 113 received RT only, while 57 received RT + CDT. There were no significant intergroup differences in terms of age, disease duration, or comorbidities, but a higher proportion of male patients and higher preoperative plasma D-dimer levels (1.23 vs. 0.84; p = .017) was observed in the RT + CDT group. There were no significant intergroup differences in terms of diagnosis, lesion characteristics, lesion location, or lesion length. Multivariate logistic regression analysis revealed that male sex (odds ratio [OR], 2.65; 95% confidence interval [CI], 1.098–6.410; p = .030) and poor distal runoff (OR, 2.94; 95% CI, 1.439–5.988; p = .003) were associated with higher rates of additional CDT. Male patients also had a significantly longer onset time, more thrombotic occlusions, and a greater frequency of in-stent restenosis. Conclusions RT alone or with CDT is a feasible primary treatment option for thrombus debulking. Sex significantly influences the effect of RT on thrombus-containing lower-limb ischaemic lesions.

A thermal-fluid-structure conjugate analysis is carried out to analyze the temperature and Von Mises stress distribution of impingement structures with and without film-cooling holes. The flow structures under stationary and rotating conditions are compared and the effect of the introduced Coriolis force in rotating channels is analyzed in detail. Turbulence model verification is accomplished by comparing the critical parameters from the experiments that involve mainstream flow and impingement cooling. Several cases of different Reynolds numbers were stimulated and the results indicate that the impingement cooling performance under rotating conditions is worse than that under stationary conditions, due to the centrifugal force enhancing the cross-flow effect in the impingement chamber. The film-cooling hole arrangement can reduce the temperature and achieve a more uniform temperature distribution at the leading edge of the blade. Compared to rotating cases, the stationary cases produce higher stress for all Reynolds numbers. For the pure impingement structure, the maximum stress region appears at the root of the blade while the maximum stress of the impingement structure with film-cooling holes locates at the exit of the film-cooling hole. Though the impingement structure with film-cooling holes achieves lower average stress of the leading edge, the maximum value of the stress is higher than the pure impingement structure. [ABSTRACT FROM AUTHOR]

Chiari Malformation Type I (CM1) is a neurological condition in which the cerebellar tonsils extend past the foramen magnum. While many studies have reported dizziness symptoms in patients with CM1, the prevalence of peripheral labyrinthine lesions is largely unknown. This study aimed to comprehensively describe the audiovestibular phenotype in a cohort of patients with CM1 expressly referred for dizziness. Twenty-four patients with CM1 and a complaint of dizziness/vertigo were evaluated. Hearing and auditory brainstem tract function were essentially normal. While vestibular abnormalities were most prevalent during rotational testing (33%), abnormal functional balance was the most common finding (40%). Patients with CM1 had a greater likelihood of exhibiting an abnormal sensory organization test (SOT) postural stability score for fixed platform conditions, and for the somatosensory analysis score. While no significant associations were identified between tonsillar ectopia extent and any vestibular/balance outcome measure, a significant negative association was identified between neck pain and the somatosensory sensory analysis score. Abnormal functional balance in the somatosensory domain was remarkable, with poorer scores associated with neck pain. An isolated peripheral vestibulopathy was present in only 8% of patients. Despite the low prevalence of vestibulopathy, vestibular/balance assessment is warranted to identify patients who may benefit from referral to specialized medical disciplines. [ABSTRACT FROM AUTHOR]

This study sought to compare the efficiency of different nitrogen (N) fertilizer forms applied to perennial ryegrass swards that were rotationally grazed by dairy cows or sheep under Irish conditions for two or three years. A 3 × 2 factorial random complete block design plot arrangement was used to compare calcium ammonium nitrate (CAN), urea and urea + N-(n-butyl) thiophosphoric triamide (urea + NBPT) at 150 and 250 kg N/ha per year. Zero nitrogen plots were also added to allow for N efficiency to be calculated. The study was conducted at four sites, giving three years of data collection at two sites and two years at the other two sites. All four sites observed similar responses to N fertilizer type and N fertilizer rate. Significant differences were observed between the 150 kg N/ha and 250 kg N/ha treatments for pre-grazing herbage yield (1346 and 1588 kg DM/ha, respectively; P < 0.001) and total herbage production (12 290 and 14 448 kg DM/ha, respectively; P < 0.001). There was no difference but a tendency for pre-grazing herbage yield to be higher for CAN and urea + NBPT than urea (1485, 1480 and 1436 kg DM/ha, for CAN, urea + NBPT and urea, respectively; P = 0.091). Total herbage production was significantly higher for CAN and urea + NBPT than urea (13 478, 13 542 and 13 087 kg DM/ha, respectively; P = 0.004). In conclusion, there was an overall benefit detected over the 10 site-years from using urea protected with NBPT v. using urea. [ABSTRACT FROM AUTHOR]

Purpose: To demonstrate safety and effectiveness of the novel ByCross® atherectomy system for treatment of complex femorodistal > 80% arterial stenosis. Materials and Methods: From September 2018 until April 2019 39 patients with 41 femorodistal lesions including the femoropopliteal and distal popliteal segments were treated in a prospective, nonrandomized pre-market approval study with 6 months follow up using the ByCross® atherectomy device (ClinicalTrials.gov identifier NCT03724279). Adjunctive treatment with balloon dilatation or stenting was allowed by the protocol. Mean patient age was 72 years with 62% male. The average lesions length was 125 ± 118 mm (30 and 450 mm) with an average reference vessel diameter of 5.2 ± 0.85 mm and a mean stenosis of 96.4 ± 6.2% based on CT or MR angiography measurements. The primary performance endpoint was defined as acute procedural success with angiographically determined residual stenosis of ≤ 50% and of ≤ 30% after atherectomy or adjunctive treatment. The primary safety endpoint was the major adverse event (MAE) rate through 30 days. Secondary endpoints were stenosis of the target lesions measured by duplex ultrasound (DUS) and the ankle-brachial pressure index (ABPI) at discharge, 30 and 180 days as well as any major adverse event (MAE) through 6 months. Results: The acute procedural success was achieved in 39/41 (95.12%) lesions, partially without wire guidance (11/41 (26.82%)). No embolic protection was used, and adjunctive angioplasty and stenting was performed in 40/41 (97.56%) and 12/41 (29.26%) lesions, respectively without device related MAE's at 30 days. Mean level of stenosis was 5.7% at discharge and 21.7% at 6 months FU measured by DUS. Mean ABPI was 0.8, 1.0 and 0.8 at baseline, discharge, and 6 months FU respectively. Conclusions: Based on the high technical success rate and the low rates of MAE's through six months, the BYCROSS® Atherectomy System has shown to be safe and effective for the crossing and atherectomy of complex lower-extremity arterial occlusions. Trial registration: October 17, 2018,retrospectively registered. ClinicalTrials.gov Identifier: NCT03724279; https://clinicaltrials.gov/ct2/show/record/NCT03724279 [ABSTRACT FROM AUTHOR]

A common task in single particle electron cryomicroscopy (cryo-EM) is the rigid alignment of images and/or volumes. In the context of images, a rigid alignment involves estimating the inner product between one image of N × N pixels and another image that has been translated by some displacement and rotated by some angle γ. In many situations the number of rotations γ considered is large (e.g. ), while the number of translations considered is much smaller (e.g. ). In these scenarios a naive algorithm requires operations to calculate the array of inner products for each image pair. This computation can be accelerated by using a Fourier–Bessel basis and the fast Fourier transform, requiring only operations per image pair. We propose a simple data driven compression algorithm to further accelerate this computation, which we refer to as the 'radial SVD'. Our approach involves linearly recombining the different rings of the original images (expressed in polar coordinates), taking advantage of the singular value decomposition (SVD) to both compress the images and optimize a certain measure of angular discriminability. When aligning multiple images to multiple targets, the complexity of our approach is O (N (log (N) + H)) per image pair, where H is the rank of the SVD used in the compression above. A very similar strategy can be used to accelerate volume alignment, using a spherical harmonic based compression, which we will refer to as a 'degree SVD'. The advantage gained by these approaches depends on the ratio between H and N ; the smaller H is the better. In many applications H can be quite a bit smaller than N while still maintaining accuracy. We present numerical results in a cryo-EM application demonstrating that the radial and degree SVD can help save a factor of 5–10 or more for both image and volume alignment. [ABSTRACT FROM AUTHOR]

Background: To assess the immediate effect and factors affecting the efficacy of rotational thrombectomy (RT) in patients with thrombus-containing lower-limb ischaemic lesions. Methods: Patients were retrospectively divided into two groups: RT and RT+ CDT (Catheter-directed thrombolysis). The RT group included patients in whom intraoperative thrombus aspiration was successful, while the RT + CDT group included patients in whom intraoperative thrombus aspiration was less effective and remedial CDT treatment was used. The primary outcome was the immediate effect of RT on thrombus-containing lower-limb ischaemic lesions. Results: From May 2015 to July 2021, 170 patients (113 men, 57 women; mean age, 74.0 years) with thrombus-containing lower-limb ischaemic lesions were treated in our centre. Of these patients, 113 received RT only, while 57 received RT + CDT. There were no significant intergroup differences in terms of age, disease duration, or comorbidities, but a higher proportion of male patients and higher preoperative plasma D-dimer levels (1.23 vs. 0.84; p =.017) was observed in the RT + CDT group. There were no significant intergroup differences in terms of diagnosis, lesion characteristics, lesion location, or lesion length. Multivariate logistic regression analysis revealed that male sex (odds ratio [OR], 2.65; 95% confidence interval [CI], 1.098–6.410; p =.030) and poor distal runoff (OR, 2.94; 95% CI, 1.439–5.988; p =.003) were associated with higher rates of additional CDT. Male patients also had a significantly longer onset time, more thrombotic occlusions, and a greater frequency of in-stent restenosis. Conclusions: RT alone or with CDT is a feasible primary treatment option for thrombus debulking. Sex significantly influences the effect of RT on thrombus-containing lower-limb ischaemic lesions. [ABSTRACT FROM AUTHOR]

In recent years, environmental problems caused by natural disasters due to global warming have seriously affected human production and life. Fortunately, with the rapid rise of the Internet of Things (IoT) technology and the decreasing power consumption of microelectronic devices, it is possible to set up a multi-node environmental monitoring system. However, regular replacement of conventional chemical batteries for the huge number of microelectronic devices still faces great challenges, especially in remote areas. In this study, we developed a rotating hybrid nanogenerator for wind energy harvesting. Using the output characteristics of triboelectric nanogenerator (TENG) with low frequency and high voltage and electromagnetic generator (EMG) with high frequency and high current, we are able to effectively broaden the output voltage range while shortening the capacitor voltage rising time, thus obtaining energy harvesting at wide frequency wind speed. The TENG adopts the flexible contact method of arch-shaped film to solve the problem of insufficient flexible contact and the short service life of the rotating triboelectric generator. After 80,000 cycles of TENG operation, the maximum output voltage drops by 7.9%, which can maintain a good and stable output. Through experimental tests, the maximum output power of this triboelectric nanogenerator is 0.55 mW at 400 rpm (wind speed of about 8.3 m/s) and TENG part at an external load of 5 MΩ. The maximum output power of the EMG part is 15.5 mW at an external load of 360 Ω. The hybrid nanogenerator can continuously supply power to the anemometer after running for 9 s and 35 s under the simulated wind speed of 8.3 m/s and natural wind speed of 5.6 m/s, respectively. It provides a reference value for solving the power supply problem of low-power environmental monitoring equipment. [ABSTRACT FROM AUTHOR]

Background: Although several factors are associated with anterior cruciate ligament (ACL) rerupture, the effect of anatomic factors associated with ACL rupture on ACL rerupture development has not been evaluated. Purpose: To determine individual anatomic parameters independently associated with ACL rerupture and the diagnostic values of these parameters. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 91 male patients with ACL rerupture and 182 age-, sex-, body mass index–, and side dominance–matched patients without rerupture who underwent ACL reconstruction with a 5-year follow-up were included. In all, 35 parameters that were previously defined as risk factors for primary ACL rupture were compared between the 2 groups. Uni- and multivariate logistic regression models were created to evaluate independently associated factors. Receiver operating characteristic curve analysis was performed for independently associated parameters to predict sensitivity, specificity, and cutoff values. Results: The mean ± standard deviation age of patients at the time of index surgery was 26.5 ± 6.7 years. Notch shape index (P =.014), tibial proximal anteroposterior (AP) distance (TPAPD) (P <.001), lateral femoral condylar AP distance (LCAPD)/TPAPD ratio (P <.001), medial meniscal cartilage bone height (P <.001), and lateral meniscal bone angle (P =.004) were found to be significantly different between the 2 groups. Only the LCAPD/TPAPD ratio (odds ratio, 2.713; 95% CI, 1.998-5.480; P <.001) was found to be independently associated with ACL rerupture development. The LCAPD/TPAPD ratio revealed 78.9% sensitivity and 75.5% specificity (area under the curve, 0.815; 95% CI, 0.760-0.870) for values above 1.52. Conclusion: The LCAPD/TPAPD ratio can be used to distinguish patients who are at risk of developing ACL rerupture from patients who are not. In the clinical practice, findings of this study may help to develop surgical and nonsurgical preventive strategies in ACL rerupture development. [ABSTRACT FROM AUTHOR]

Due to their lack of pollution and long replacement cycles, piezoelectric energy harvesters have gained increasing attention as emerging power generation devices. However, achieving effective energy harvesting in ultra-low-frequency (3 Hz) under a rotational excitation of 0.42 Hz, demonstrating excellent energy-harvesting characteristics.

Conventional black box machine learning (ML) algorithms for gas-phase species identification from THz frequency region absorption spectra have been reported in the literature. While the robust classification performance of such ML models is promising, the black box nature of these ML tools limits their interpretability and acceptance in application. Here, a one-dimensional convolutional neural network (CNN), VOC-Net, is developed and demonstrated for the classification of absorption spectra for volatile organic compounds (VOCs) in the THz frequency range, specifically from 220 to 330 GHz where prior experimental data is available. VOC-Net is trained and validated against simulated spectra, and also demonstrated and tested against experimental spectra. The performance of VOC-Net is examined by the consideration of confusion matrices and receiver-operator-characteristic (ROC) curves. The model is shown to be 99+% accurate for the classification of simulated spectra and 97% accurate for the classification of noisy experimental spectra. The model's internal logic is examined using the Gradient-weighted Class Activation Mapping (Grad-CAM) method, which provides a visual and interpretable explanation of the model's decision making process with respect to the important distinguishing spectral features. [ABSTRACT FROM AUTHOR]

The present research presents a new advanced mathematical model based on memory-dependent generalized thermoelasticity with time delays to investigate the thermoelastic vibrations of rotating nanobeams with variable thermal conductivity. In contrast to the traditional derivative, it turns out that the memory-dependent derivative of physical processes, which represents the average total rate of change over a period of time, depends on the previous states. Furthermore, the influence of size on the dynamic responses to thermoelastic vibrations in nanobeams is taken into account. The silicon nanobeam was heated with a non-Gaussian laser beam, which caused vibrations due to the thermo-elastic damping effect. The problem has been treated analytically in the transformed field with the help of the Laplace transform and numerically inverted using a suitable numerical approach based on the Fourier series expansion method. The significance of the memory-dependent derivative elements (kernel functions, time delay) as well as the effects of changing the thermal conductivity, angular velocity of rotation, and nonlocal parameters on the behavior of the studied fields were analyzed. According to the results, it was shown that the function of the nucleus in its various forms, as well as the time delay, has a significant influence on the memory-dependent heat wave propagation. In the presence of a memory-dependent derivative, statistically significant differences in physical quantities for distinct models were detected. [ABSTRACT FROM AUTHOR]

Piezoelectric energy harvesting is a widely used and environmentally friendly power generation technology, which can provide power for wireless electronic devices and low-power sensors. In this paper, a magnetically excited rotating piezoelectric energy harvester is proposed, which can generate output voltages of more than 15 V at frequencies below 13 Hz, where the maximum output voltage is 55.62 V. Through the rotation of the rotamer, magnetic coupling between magnetic blocks drives piezoelectric elements to vibrate nonlinearly to generate electrical energy. Structural prototypes with different parameters were designed and produced after analyzing the working principle and theoretical model of the entire piezoelectric system, and a series of experimental verifications were carried out on the theoretical model. The experimental results show that the energy harvester has the best power generation effect when the weight of the magnet mass is 6 g, the radial excitation distance is 5 mm, and multiple piezoelectric beams are connected in series. When the piezoelectric beams are connected in series and rotational speed is 550 r/min, the external load resistance is 75 kΩ, its maximum root mean square output voltage and average output power are 33.12 V and 14.625 mW, respectively. The energy harvesting system can light up 260 LED lights under the excitation of 550 r/min. [ABSTRACT FROM AUTHOR]

Bicycle helmets are designed to attenuate both the linear and rotational response of the head during an oblique impact. Here we sought to quantify how the effectiveness of one popular rotation-attenuating system (MIPS) varied across 3 test headform conditions (bare, covered in stockings, and hair), 3 oblique impact orientations, and 4 impact speeds. We conducted 72 freefall drop tests of a single helmet model with and without MIPS onto a 45° angled anvil and measured the peak linear (PLA) and angular acceleration (PAA) and computed the angular velocity change (PAV) and brain injury criterion (BrIC). Across all headform conditions, MIPS reduced PAA and PAV by 38.2 and 33.2% respectively during X-axis rotation, 47.4 and 38.1% respectively during Y-axis rotation, and 22.9 and 20.5% during a combined ZY-axis rotation. Across all impact orientations, PAA was reduced by 39% and PAV by 32.4% with the bare headform while adding stockings reduced PAA and PAV by 41.6 and 36% respectively and the hair condition reduced PAA and PAV by 30.2 and 24.4% respectively. In addition, our data reveal the importance of using consistent headform conditions when evaluating the effect of helmet systems designed to attenuate head rotations during oblique impacts. [ABSTRACT FROM AUTHOR]

Rotational energy harvesting technology has attracted more and more attention recently. This paper presents a piezoelectric rotational energy harvester that can be mounted with an offset distance from the rotation center. The piezoelectric energy harvester is designed to be dynamically excited by the force due to gravity, which causes the piezoelectric cantilever beams in the harvester to vibrate periodically as the harvester rotates. A novel design of the harvester structure with a hollow mass is proposed and analyzed in this paper. Experiments were performed to investigate the design and analysis. A power output of 106~2308 μW can be achieved at the rotating frequencies of 0.79~14 Hz with a piezoelectric cantilever beam in the prototyped energy harvester. Results showed that the prototyped harvester can be mounted on a rotating wheel hub and output sufficient power in a wide frequency range for wireless monitoring sensors. [ABSTRACT FROM AUTHOR]

Poppet valves are commonly used as relief valves, pressure regulators, selectors, and inlet and exhaust valves in automobile internal combustion (IC) engines. Nanofinishing of ridge profiles of the poppet valve is a challenging task due to its narrowness. This article presents the precise finishing of narrow ridge profiles of poppet valves at optimum process parameters in the rotational-magnetorheological fluid-based finishing (R-MRFF) process using a novel magnet fixture. Statistical analysis is used to determine the impact of each process parameter. Further, simulation of finishing forces in the R-MRFF process is performed using software that applies the finite element technique. Investigation of finishing forces assists in controlling the process precisely. An analytical model is formulated for calculating the number of abrasive particles acting on nickel–aluminum–bronze alloy poppet profiles to anticipate final material dislodgement. The significant process parameters for surface roughness are abrasive volume concentration, poppet rpm, poppet vertical feed rate, and carbonyl iron particle (CIP) volume concentration. The minimum obtained surface roughness (Ra) at poppet valve profiles is 23.5 nm. The final finished poppet valve may have a longer service life and improved wear and corrosion resistance at maximum temperature and pressure. [ABSTRACT FROM AUTHOR]

The traditional three-electrode Velocity Map Imaging (VMI) electrostatic lens developed by Eppink and Parker has proven to be a useful tool in a wide range of applications in molecular dynamics, including photodissociation experiments taking place in a molecular beam. However, in some other cases, such as crossed molecular beam experiments, the large diameter (typically ∼70 mm) of this conventional VMI lens can be inconvenient. We describe here a VMI lens with a much smaller diameter (down to ∼20 mm) using tubular electrodes. The performance is evaluated by imaging O+ fragments produced by the photodissociation of O2 at around 225 nm, and by inelastic scattering of NO with Ar. Our results suggest that the recorded images are of acceptable quality compared to those from a standard lens while achieving a fourfold reduction of the VMI lens diameter. [ABSTRACT FROM AUTHOR]

With aging society, one of the more challenging obstacles in percutaneous coronary interventions are calcified coronary lesions. Calcified lesions may impede stent delivery, limit balloon and stent expansion, cause uneven drug distribution, and hinder wire advancement. Even in the setting of acceptable procedural success, vessel calcification is independently associated with increased target lesion revascularization rates at follow-up and lower survival rates. In order to effectively manage such lesions, dedicated technologies have been developed. Atherectomy aims at excising tissue and debulking plaques, as well as compressing and reshaping the atheroma, generally referred to as lesion preparation that enables further balloon and/or stent expansion in contemporary clinical practice. In the current review, we will discuss the available methods for atherectomy, including rotational, orbital, and excimer laser coronary atherectomy, as well as intravascular lithotripsy. In addition, we will review the role of imaging in calcified lesions. [ABSTRACT FROM AUTHOR]

This study sought to evaluate head accelerations in both players involved in a football collision. Players on two opposing Canadian university teams were equipped with helmet mounted sensors during one game per season, for two consecutive seasons. A total of 276 collisions between 58 instrumented players were identified via video and cross-referenced with sensor timestamps. Player involvement (striking and struck), impact type (block or tackle), head impact location (front, back, left and right), and play type were recorded from video footage. While struck players did not experience significantly different linear or rotational accelerations between any play types, striking players had the highest linear and rotational head accelerations during kickoff plays (p ≤.03). Striking players also experienced greater linear and rotational head accelerations than struck players during kickoff plays (p =.001). However, struck players experienced greater linear and rotational accelerations than striking players during kick return plays (p ≤.008). Other studies have established that the more severe the head impact, the greater risk for injury to the brain. This paper's results highlight that kickoff play rule changes, as implemented in American college football, would decrease head impact exposure of Canadian university football athletes and make the game safer. [ABSTRACT FROM AUTHOR]

In recent years, environmental problems caused by natural disasters due to global warming have seriously affected human production and life. Fortunately, with the rapid rise of the Internet of Things (IoT) technology and the decreasing power consumption of microelectronic devices, it is possible to set up a multi-node environmental monitoring system. However, regular replacement of conventional chemical batteries for the huge number of microelectronic devices still faces great challenges, especially in remote areas. In this study, we developed a rotating hybrid nanogenerator for wind energy harvesting. Using the output characteristics of triboelectric nanogenerator (TENG) with low frequency and high voltage and electromagnetic generator (EMG) with high frequency and high current, we are able to effectively broaden the output voltage range while shortening the capacitor voltage rising time, thus obtaining energy harvesting at wide frequency wind speed. The TENG adopts the flexible contact method of arch-shaped film to solve the problem of insufficient flexible contact and the short service life of the rotating triboelectric generator. After 80,000 cycles of TENG operation, the maximum output voltage drops by 7.9%, which can maintain a good and stable output. Through experimental tests, the maximum output power of this triboelectric nanogenerator is 0.55 mW at 400 rpm (wind speed of about 8.3 m/s) and TENG part at an external load of 5 MΩ. The maximum output power of the EMG part is 15.5 mW at an external load of 360 Ω. The hybrid nanogenerator can continuously supply power to the anemometer after running for 9 s and 35 s under the simulated wind speed of 8.3 m/s and natural wind speed of 5.6 m/s, respectively. It provides a reference value for solving the power supply problem of low-power environmental monitoring equipment.