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1.
J Surg Educ ; 2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38834433

RESUMEN

OBJECTIVES: Previous literature has consistently documented harassment and discrimination in surgery. These experiences may contribute to the continuing gender inequity in surgical fields. The objective of our study was to survey Canadian surgeons and surgical trainees to gain a greater understanding of the experience of harassment across genders, career stage, and specialty. METHODS: A cross-sectional, online survey was distributed to Canadian residents, fellows, and practicing surgeons in general surgery, plastic surgery, and neurosurgery through their national society email lists and via social media posts. RESULTS: There were 194 included survey respondents (60 residents, 11 fellows, and 123 staff) from general surgery (44.8%), plastic surgery (42.7%), and neurosurgery (12.5%). 59.8% of women reported having experienced harassment compared to only 26.0% of men. Women were significantly more likely to be harassed by colleagues and patients/families compared to men. Residents (62.5%) were two times more likely to report being harassed compared to fellows/staff (38.3%). Residents were significantly more likely to be harassed by patients/families while fellows/staff were more likely to be harassed by colleagues. There were no significant differences in self-reported harassment across the three surgical specialties. There was no significant difference in rates of reported harassment between current residents (62.5%), and fellow/staff recollections of their experiences of harassment during residency (59.2%). CONCLUSIONS: The prevalence of gender-based discrimination remains high and harassment prevalence remains largely unchanged from when current staff were in residency. Our findings highlight a need to implement systemic changes to support the increasing number of women entering surgery, and to improve surgical culture to continue to attract the best and brightest to the field.

2.
Med Sci Educ ; 34(1): 71-76, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38510392

RESUMEN

An escape room is a team-based activity that requires players to solve a series of puzzles to complete a story and "break out" of a room. It has recently gained traction in medical education for its ability to interactively and effectively present learning objectives. This was a prospective educational study that describes the successful application of a nephrology themed escape room for first- and second-year medical students. Compared to pre-escape room participation, the 52 students demonstrated a statistically significant improvement in self-reported knowledge for renal physiology (p < 0.01), pharmacology (p < 0.01), pathology (p < 0.01), and relevant clinical practice guidelines (p < 0.01). A majority of the students also claimed that the escape room was "more effective" than traditional lectures (80.8%) and textbooks (73.1%) and "equally effective" as third-party board preparation resources (69.2%) and their institution's problem-based learning curriculum (51.9%). The escape room also facilitated a high-level peer-to-peer collaboration with 82.7% and 76.9% of students reporting that they worked with someone in their year and outside of their year for at least half of the game, respectively. Ninety-five percent of the first-years and 84.6% of the second-years believed that the escape room was effective at preparing them for their respective exams, and an overwhelming majority (90.4%) described the escape room as "very enjoyable." Overall, this nephrology themed escape room was an engaging and well received educational modality and may be an effective supplemental study resource for medical students. Further studies are needed to assess knowledge acquisition. Supplementary Information: The online version contains supplementary material available at 10.1007/s40670-023-01917-6.

3.
J Biomech ; 152: 111571, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-37027962

RESUMEN

To investigate the biomechanical properties of rat bladder tissue after spinal cord injury (SCI) using uniaxial tensile testing. Evidence suggests the bladder wall undergoes remodeling following SCI. There is limited data describing the biomechanical properties of bladder wall after SCI. This study describes the changes in elastic and viscoelastic mechanical properties of bladder tissue using a rat model after SCI. Seventeen adult rats received mid-thoracic SCI. Basso, Beattie, and Bresnahan (BBB) locomotor testing was performed on the rats 7-14 days after injury quantifying the degree of SCI. Bladder tissue samples were collected from controls and spinal injured rats at 2- and 9-weeks post-injury. Tissue samples underwent uniaxial stress relaxation to determine instantaneous and relaxation modulus as well as monotonic load-to failure to determine Young's modulus, yield stress and strain, and ultimate stress. SCI resulted in abnormal BBB locomotor scores. Nine weeks post-injury, instantaneous modulus decreased by 71.0% (p = 0.03) compared to controls. Yield strain showed no difference at 2 weeks post-injury but increased 78% (p = 0.003) in SCI rats at 9 weeks post-injury. Compared to controls, ultimate stress decreased 46.5% (p = 0.05) at 2 weeks post-injury in SCI rats but demonstrated no difference at 9 weeks post-injury. The biomechanical properties of rat bladder wall 2 weeks after SCI showed minimal difference compared to controls. By week 9, SCI bladders had a reduction in instantaneous modulus and increased yield strain. The findings indicate biomechanical differences can be identified between control and experimental groups at 2- and 9-week intervals using uniaxial testing.


Asunto(s)
Traumatismos de la Médula Espinal , Vejiga Urinaria , Ratas , Animales , Ratas Sprague-Dawley , Médula Espinal
4.
J Pediatr Urol ; 19(3): 292.e1-292.e7, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36842912

RESUMEN

INTRODUCTION: There is controversy surrounding the association between caudal block and complication rates after hypospadias repair. Conflicting results have been reported mostly from single-center, low volume studies and those that did not include relevant variables. OBJECTIVES: We hypothesized that caudal block is not associated with increased rates of reoperation after primary repair and is associated with more complex hypospadias surgery. STUDY DESIGN: The Clinical Practice Solutions Center database was queried to identify patients who received a primary hypospadias repair between 2009 and 2010. Primary hypospadias repair was further categorized as meatal advancement and glanduloplasty, distal, one-stage proximal, or one-stage perineal repair. Anesthesia coding was evaluated to identify those who received a caudal block. Any revision surgery was captured between 2009 and 2019 and the types of revision surgeries were identified. Variables such as caudal block, age, insurance type, surgeon volume, and surgeon years in practice were analyzed with mixed effects multiple logistic regression models. RESULTS: The dataset query identified 3343 pediatric males who had primary hypospadias repair. The procedures were performed by 50 surgeons at 27 hospitals. Primary surgeries included meatal advancement and glanduloplasty (23%), distal (69%), proximal (6.9%), and perineal repairs (1%). Caudal block was administered to 42% of patients. Utilization of caudal block was not associated with type of primary surgery (p = 0.21). Adjusting for all other variables, increased patient age was associated with decreased usage of caudal block (p < 0.001). Analysis did not demonstrate a statistically significant association between utilization of caudal block with rates of revision surgery. CONCLUSIONS: This large, multi-institution study demonstrates that the use of caudal block was not associated with more complex hypospadias surgery nor statistically significantly associated with increased rates of revision surgery after primary hypospadias repair.


Asunto(s)
Hipospadias , Bloqueo Nervioso , Masculino , Humanos , Niño , Lactante , Hipospadias/cirugía , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/cirugía , Uretra/cirugía , Bloqueo Nervioso/métodos , Modelos Logísticos , Resultado del Tratamiento , Estudios Retrospectivos
5.
Phys Chem Chem Phys ; 25(4): 3199-3210, 2023 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-36625155

RESUMEN

TiO2 has been extensively studied in many fields including photocatalysis, electrochemistry, optics, etc. Understanding the mechanism of the anatase-rutile phase transition (ART) process is critical for the design of TiO2-based high-activity photocatalysts and tuning its properties for other applications. In this work, the ART process using individual anatase micro-particles with a large percentage of (001) facets was monitored and studied. Phase concentration evolution obtained via Raman microscopy was correlated with the morphological evolution observed in scanning electron microscope (SEM) images. The ART of anatase microcrystals is dominated by surface nucleation and growth, but the ART processes of individual anatase particles are distinctive and depend on the various rutile nucleation sites. Two types of transformation pathways are observed. In one type of ART pathway, the rutile phase nucleated at a corner of an anatase microcrystal and grew in one direction along the edge of the crystal firstly followed by propagation over the rest of the microcrystal in the orthogonal direction on the surface and to the bulk of the crystal. The kinetics of the ART follows the first-order model with two distinct rate constants. The fast reaction rate is from the surface nucleation and growth, and the slow rate is from the bulk nucleation and growth. In the other type of ART pathway, multiple rutile nucleation sites formed simultaneously on different edges and corners of the microcrystal. The rutile phase spread over the whole crystal from these nucleation sites with a small contribution of bulk nucleation. Our study on the ART of individual micro-sized crystals bridges the material gap between bulk crystals and nano-sized TiO2 particles. The anatase/rutile co-existing particle will provide a perfect platform to study the synergistic effect between the anatase phase and the rutile phase in their catalytic performances.

6.
Neuromuscul Disord ; 33(1): 5-14, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36572586

RESUMEN

Duchenne Muscular Dystrophy (DMD) is an X-linked recessive neuromuscular disorder characterized by progressive muscle weakness due to loss of function mutations in the dystrophin gene. Variation in clinical presentation, the rate of disease progression, and treatment responsiveness have been observed amongst DMD patients, suggesting that factors beyond the loss of dystrophin may contribute to DMD pathophysiology. Epigenetic mechanisms are becoming recognized as important factors implicated in the etiology and progression of various diseases. A growing number of genetic syndromes have been associated with unique genomic DNA methylation patterns (called "episignatures") that can be used for diagnostic testing and as disease biomarkers. To further investigate DMD pathophysiology, we assessed the genome-wide DNA methylation profiles of peripheral blood from 36 patients with DMD using the combination of Illumina Infinium Methylation EPIC bead chip array and EpiSign technology. We identified a unique episignature for DMD that whose specificity was confirmed in relation other neurodevelopmental disorders with known episignatures. By modeling the DMD episignature, we developed a new DMD episignature biomarker and provided novel insights into the molecular pathogenesis of this disorder, which have the potential to advance more effective, personalized approaches to DMD care.


Asunto(s)
Distrofia Muscular de Duchenne , Humanos , Distrofia Muscular de Duchenne/diagnóstico , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/patología , Distrofina/genética , Distrofina/metabolismo , Metilación de ADN
7.
Int J Exerc Sci ; 15(6): 1578-1586, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36582967

RESUMEN

Prior studies have demonstrated the beneficial effects of real-time data feedback (RTF) on athletic performance and motivation. Despite this evidence, the lack of practical means to implement RTF has hindered its widespread adoption. Recently, a smart-resisted sled push was developed to improve athletic power by utilizing electromagnetic motors as a resistance mechanism, coupled with an RTF display. Thirty healthy college-aged male football players were recruited in this randomized, crossover designed study to examine the efficacy of the RTF to improve power output. Participants were randomized into either group 1 (receiving RTF first then no RTF) or group 2 (receiving no RTF first then RTF) during six, 10-meter sled pushes with 3 min rest intervals. The first three pushes were set to an easier level (L1) and the last three were set to a resistance level twice that of the first three runs (L2). A one-month washout period was enforced. For trials 1-3 (L1) (p = 0.026, t = -2.34, ES = -0.428) and 4-6 (L2) (p = 0.035, t = -2.22, ES = -0.405), peak power output (the average peak power output over the course of trials 1-3 and 4-6) was greater in both groups when receiving RTF compared to no-RTF. These findings demonstrate the effectiveness of RTF in augmenting power output during performance training.

8.
J Tissue Eng Regen Med ; 16(8): 718-731, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35567775

RESUMEN

Large animal testing and clinical trials using bioengineered bladder for augmentation have revealed that large grafts fail due to insufficient blood supply. To address this critical issue, an in vivo staged implant strategy was developed and evaluated to create autologous, vascularized bioengineered bladder tissue with potential for clinical translation. Pig bladders were used to create acellular urinary bladder matrices (UBMs), which were implanted on the rectus abdominus muscles of rats and pigs to generate cellular and vascular grafts. Rectus-regenerated bladder grafts (rrBGs) were highly cellularized and contained an abundance of CD31-positive blood vessels, which were shown to be functional by perfusion studies. Muscle patterns within grafts showed increased smooth muscle formation over time and specifically within the detrusor compartment, with no evidence of striated muscle. Large, autologous rrBGs were transplanted to the pig bladder after partial cystectomy and compared to transplantation of control UBMs at 2 weeks and 3 months post-transplant. Functional, ink-perfused blood vessels were found in the central portion of all rrBGs at 2 weeks, while UBM grafts were significantly deteriorated, contracted and lacked central cellularization and vascularization. By 3 months, rrBGs had mature smooth muscle bundles and were morphologically similar to native bladder. This staged implantation technique allows for regeneration and harvest of large bladder grafts that are morphologically similar to native tissue with functional vessels capable of inosculating with host bladder vessels to provide quick perfusion to the central area of the large graft, thereby preventing early ischemia and contraction.


Asunto(s)
Músculo Liso , Vejiga Urinaria , Animales , Músculo Liso/fisiología , Pelvis , Perfusión , Ratas , Regeneración/fisiología , Porcinos
9.
Artículo en Inglés | MEDLINE | ID: mdl-36612530

RESUMEN

Exergaming, combining elements of video game into the realm of exercise, has recently incorporated immersive virtual reality (IVR) with resistance training. Thirty-two participants (14 females, mean age = 24.3) were randomized to IVR or self-directed control group (SELF) and worked out thrice weekly for 12 weeks (for 36 sessions). The IVR group spent 14 fewer minutes per session (p < 0.001) while reporting the sessions "enjoyable'. Compared to SELF, the IVR group had significantly greater improvement in changes from baseline to post-training in upper-and-lower muscular strength (1-RM) and muscular endurance (85% 1-RM) (14.3 kg vs. 10.0 kg for 1-RM upper, 28.6 kg vs. 22.5 kg for 1-RM lower, 2.6 reps vs. 1.9 reps for 85% 1-RM of upper, 2.7 vs. 2.0 reps for 85% 1-RM of lower, all p < 0.001), peak leg power (1424 vs. 865 W, p < 0.001), body fat% (−3.7% vs. −1.9%, p < 0.001), heart rate variability (4.3 vs. 1.8 ms, p < 0.001), rVO2max (3.28 vs. 0.89 mL/min/kg, p < 0.001) with decreased systolic BP (−0.4 vs. −2.3 mmHg, p < 0.001), and level of perceived exertion during workouts (RPE 14 vs. 16, p < 0.001). With its high-paced and action-filled gaming coupled with superior fitness and cardiometabolic outcomes, this IVR exergaming platform should be considered as another exercise modality for performance and health-related training.


Asunto(s)
Enfermedades Cardiovasculares , Juegos de Video , Realidad Virtual , Femenino , Humanos , Adulto Joven , Adulto , Videojuego de Ejercicio , Ejercicio Físico/fisiología
10.
Int J Exerc Sci ; 15(7): 261-275, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36896022

RESUMEN

The purpose of this exploratory study was to characterize muscle activation via surface electromyography (sEMG), user-perceived exertion, and enjoyment during a 30-minute session of immersive virtual reality (IVR) cable resistance exergaming. Ten healthy, college-aged males completed a signature 30-minute exergaming session using an IVR adaptive cable resistance system that incorporated six traditional compound exercises. Muscle activation (sEMG) was captured during the session with a wearable sEMG system. Rated of Perceived Exertion (RPE) and Physical Activity Enjoyment Scale (PACES) were recorded following the session. Pectoralis major showed the highest activation during chest press, deltoids showed the highest activation on overhead press, latissimus dorsi showed the highest activation during lat pulldown and row exercises, hamstrings were the most activated muscles during Romanian deadlift, and glutes showed the highest activity during squats. RPE and PACES mean scores were 14 (1) and 4.27 (0.38), respectively. IVR exergaming with resistance cable training provides an enjoyable experience and distracts practitioners from exertion while exercising at a high intensity. Results from this study suggest similar muscle activation responses compared to traditional resistance exercises as demonstrated with prior evidence. This novel form of exercise might have important repercussions for improving health outcomes among those who find it challenging to adhere to and enjoy exercise routines, as well as with little knowledge on how to progress in their resistance training. Further investigations are needed to explore long-term adaptations and to assess if IVR exergaming has additional benefits compared to traditional resistance training.

11.
ACS Appl Mater Interfaces ; 13(48): 57075-57083, 2021 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-34797627

RESUMEN

Two-dimensional organic-inorganic lead halide perovskites are generating great interest due to their optoelectronic characteristics such as high solar energy conversion efficiency and a tunable direct band gap in the visible regime. However, the presence of defect states within the two-dimensional crystal structure can affect these properties, resulting in changes to their band gap emission as well as the emergence of nonlinear optical phenomena. Here, we have investigated the effects of the presence of defect states on the nonlinear optical phenomena of the 2D hybrid perovskite (BA)2(MA)2Pb3Br10. When two pulses, one narrowband pump pulse centered at 800 nm and one supercontinuum pulse with bandwidth from 800-1100 nm, are incident on a perovskite flake, degenerate four-wave mixing (FWM) occurs, with peaks corresponding to the energy levels of the defect states present within the crystal. The longer carrier lifetime of the defect state, in comparison to that of virtual transitions that take place in nonresonant FWM processes, allows for a larger population of electrons to be excited by the second pump photon, resulting in increased FWM signal at the defect energy levels. The quenching of the two-photon luminescence as flake thickness increases is also observed and attributed to the increased presence of defects within the flake at larger thicknesses. This technique shows the potential of detecting defect energy levels in crystals using FWM for a variety of optoelectronic applications.

12.
Games Health J ; 10(5): 361-369, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34403592

RESUMEN

Objective: To measure metabolic and physiological demand, subjective fatigue, and enjoyment during a signature 30-minute immersive virtual reality (IVR) adaptive cable resistance exergaming session. Methods: Fourteen healthy college-aged individuals (seven females) were initially acquainted with the IVR equipment and gameplay dynamics. Participants then underwent a 30-minute IVR exergaming session performing six different cable resistance exercises. A portable metabolic gas exchange analyzer concurrently assessed energy expenditure (EE) through indirect calorimetry while a chest-worn monitor captured heart rate (HR). Participants subsequently completed questionnaires, including the Borg scale for rating of perceived exertion (RPE), Physical Activity Enjoyment Scale (PACES), and Simulator Sickness Questionnaire (SSQ). Results: The mean EE, mean metabolic equivalent, and average total calories expended during the 30-minute session were 14.7 (standard deviation [SD] 2.8) kcal/minute, 12.9 (SD 0.5), and 440 (SD 84) kcals respectively. The mean HR was 176 (SD 3.1) beats per minute (bpm) with a mean max HR of 188 SD (SD 2.9) bpm. The combined training volume among all participants was 16,102 kg (SD 4137). Participants classified the IVR training session to be "somewhat hard-to-hard" with a RPE score of 14 (SD 1) while indicating the session to be "enjoyable" with a PACES score of 4.31 (SD 0.36). The participants did not report any cybersickness symptoms, demonstrating an average total SSQ score of 24.04 (SD 24.13). Conclusions: IVR exergaming incorporating cable resistance training elicits high EE and physiological demand with high enjoyment scores while attenuating perceived fatigue. The potential for IVR to elicit these acute training effects over long-term training periods warrants further investigation into its contribution to fitness and health.


Asunto(s)
Juegos de Video , Realidad Virtual , Calorimetría Indirecta , Ejercicio Físico , Femenino , Humanos , Esfuerzo Físico , Adulto Joven
13.
Trauma Case Rep ; 34: 100500, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34195341

RESUMEN

Pediatric physicians and motor vehicle safety experts have been advocating for change in child passenger restraint practices for decades. As professional recommendations evolve to support extended rear-facing restraint, actual practices remain disparate. We report a case of pediatric cervical spine fracture due to motor vehicle collision, an uncommon, yet predictable, pattern of injury for which prevention education is undoubtedly preferable to managing the consequences of premature forward-facing in vulnerable pediatric patients. Currently, 9 kg is a minimum legal standard for forward-facing child restraint system use in Ontario, rather than a recommended transition time. We advise that parents should be counselled on the benefits of rear-facing as long as possible and discuss realistic transition times using their child restraint system manual as a reference, with the goal of approaching, but not exceeding, the maximum weight, height and fit requirements for optimal safety.

14.
Clin Case Rep ; 9(3): 1672-1676, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33768912

RESUMEN

We report a case of neonatal nemaline myopathy with a de novo TPM3 mutation, which has been classified as a likely pathogenic mutation. With the expanding use of genetic testing in congenital myopathies, genotype-phenotype descriptions of novel variants are important to inform clinical care, diagnosis, genetic counseling, and management of disease.

15.
Front Immunol ; 11: 594136, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33193444

RESUMEN

The loss of efferocytosis-the phagocytic clearance of apoptotic cells-is an initiating event in atherosclerotic plaque formation. While the loss of macrophage efferocytosis is a prerequisite for advanced plaque formation, the transcriptional and cellular events in the pre-lesion site that drive these defects are poorly defined. Transcriptomic analysis of macrophages recovered from early-stage human atherosclerotic lesions identified a 50-fold increase in the expression of GATA2, a transcription factor whose expression is normally restricted to the hematopoietic compartment. GATA2 overexpression in vitro recapitulated many of the functional defects reported in patient macrophages, including deficits at multiple stages in the efferocytic process. These findings included defects in the uptake of apoptotic cells, efferosome maturation, and in phagolysosome function. These efferocytic defects were a product of GATA2-driven alterations in the expression of key regulatory proteins, including Src-family kinases, Rab7 and components of both the vacuolar ATPase and NADPH oxidase complexes. In summary, these data identify a mechanism by which efferocytic capacity is lost in the early stages of plaque formation, thus setting the stage for the accumulation of uncleared apoptotic cells that comprise the bulk of atherosclerotic plaques.


Asunto(s)
Aterosclerosis/etiología , Factor de Transcripción GATA2/genética , Expresión Génica , Macrófagos/metabolismo , Animales , Aterosclerosis/metabolismo , Aterosclerosis/patología , Línea Celular , Células Cultivadas , Susceptibilidad a Enfermedades , Vesículas Extracelulares/metabolismo , Humanos , Macrófagos/inmunología , Ratones , Fagocitosis/genética , Fagocitosis/inmunología , Fagosomas/metabolismo
16.
Int J Exerc Sci ; 13(4): 1206-1216, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33042371

RESUMEN

The demand for efficient and effective exercises has grown in concert with increased attention to fitness as a determinant of overall health. While past studies have examined the benefits traditional conditioning exercises, there have been few investigations of high intensity functional training (HIFT). The aim of this study was to measure the energy expenditure and relative intensity from participation in a signature, 35-minute group-based HIFT regimen. During the HIFT session, 13 volunteers (aged 23-59 years, 6 females) donned a portable breath-by-breath gas analyzer and a heart rate monitor. Mean caloric expenditure (528 ± 62 kcal), maximum heart rate (172 ± 8 bpm), and metabolic equivalents (12.2 ± 1.4 kcal/kg/h) were characterized as a vigorous-intensity activity according to the Compendium of Physical Activities guidelines. Moreover, implementing this high energy expenditure session twice weekly may comport with Physical Activity Guidelines for Americans weekly physical activity recommendations. HIFT training may provide time-efficient exercise for those seeking exercise-related health benefits.

17.
Nanoscale ; 12(13): 7109-7115, 2020 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-32191255

RESUMEN

Liquid suspensions of carbon nanotubes, graphene and transition metal dichalcogenides have exhibited excellent performance in optical limiting. However, the underlying mechanism has remained elusive and is generally ascribed to their superior nonlinear optical properties such as nonlinear absorption or nonlinear scattering. Using graphene as an example, we show that photo-thermal microbubbles are responsible for optical limiting as strong light scattering centers: graphene sheets absorb incident light and become heated up above the boiling point of water, resulting in vapor and microbubble generation. This conclusion is based on the direct observation of bubbles above the laser beam as well as a strong correlation between laser-induced ultrasound and optical limiting. In situ Raman scattering of graphene further confirms that the temperature of graphene under laser pulses rises above the boiling point of water but still remains too low to vaporize graphene and create graphene plasma bubbles. Photo-thermal bubble scattering is not a nonlinear optical process and requires very low laser intensity. This understanding helps us to design more efficient optical limiting materials and understand the intrinsic nonlinear optical properties of nanomaterials.

18.
Int J Exerc Sci ; 13(4): 1783-1793, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33414880

RESUMEN

Analysis of metabolic gas exchange and muscular output measures have enabled researchers to index activity intensity and energy expenditure for a myriad of exercises. However, there is no current research that investigates the physiological demands of riding electrically powered skateboards. The aim of this study was to measure the energetic cost and muscular trends of riding a novel electrically powered skateboard engineered to emulate snowboarding on dry-land. While riding the skateboard, eight participants (aged 21-37 years, 1 female) donned a portable breath-by-breath gas analyzer to measure energy expenditure (mean = 12.5, SD = 2 kcal/min), maximum heart rate (mean = 158, SD = 27 bpm), and metabolic equivalent (mean = 10.5, SD = 2 kcal/kg/h). By comparison, snowboarding has a metabolic equivalent (MET) of 8.0. Per the Compendium of Physical Activities guidelines, the predicted MET values for riding an electrically powered skateboard qualifies as vigorous-intensity activity. Four participants additionally wore a surface EMG embedded garment to record the percentage of maximum voluntary contraction (%MVC) of lower limb muscle groups. The inner quadriceps had the most pronounced mean peak muscle activation of 145%MVC during frontside and 164%MVC during frontside turns. EMG recordings showed 11.7%MVC higher utilization during backside turns compared to frontside turns while riding the electrically powered skateboard, which is similar to trends observed in alpine snowboarders. Therefore, electrically powered skateboards may be a promising technology for snowboarders and non-snowboarders alike to burn calories and increase physical activity year-round.

19.
Int J Exerc Sci ; 13(7): 1794-1806, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33414888

RESUMEN

Prior studies have examined the benefits of graduated compression garments (GCG) with regards to diverse exercise regimens; however, the relationship between GCG and the autonomic nervous system (ANS) has not been fully explored. The aim of this study was to examine Heart Rate Variability (HRV) trends-a proxy for ANS modulation-in response to donning GCG during a progressive overload training regimen designed to induce overtraining. Ten college-aged male novice runners were recruited for the 8-week crossover study. After three weeks of monitored free living, participants were randomized and blinded to an intervention group that donned a lower-body GCG during a two-week exercise regimen or a control group that donned a visually identical but non-compressive sham during identical training. No significant difference in HRV was calculated by the natural logarithm of the root mean square of successive RR-interval differences (lnRMSSD) between the 3-week free-living baseline and GCG intervention periods (P = 0.3040). The mean lnRMSSD was greater during the free-living phase and GCG intervention compared to the sham placebo (P < 0.001 and <0.001 respectively). With regard to the daily fluctuation of lnRMSSD, no significant differences were found between free-living and intervention (P = 1.000). Conversely, the intervention period demonstrated reduced daily fluctuation of lnRMSSD relative to the Sham placebo group (P = 0.010). These novel findings posit that post training use of a commercially available graduated compression garment in novice runners may be effective in counteracting some deleterious effects from overtraining while attenuating its effects on vagally-mediated HRV.

20.
Retin Cases Brief Rep ; 14(2): 178-180, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-28957956

RESUMEN

PURPOSE: To report a case of inducible transient central retinal artery vasospasm with associated imaging. METHODS: Observational case report. RESULTS: A 51-year-old man presented for outpatient follow-up for recurrent inducible transient vision loss in his right eye. He experienced an episode during examination and was found to have central retinal artery vasospasm. Fundus photography and fluorescein angiography obtained during his vasospastic attack confirmed retinal arterial vasospasm. Treatment with a calcium-channel blocker (nifedipine) has been effective in preventing recurrent attacks. CONCLUSION: Idiopathic primary vasospasm is a rare cause of transient vision loss that is difficult to confirm because of the transient nature. We obtained imaging showing the initiation and resolution of the vasospastic event. The patient was then successfully treated with a calcium-channel blocker.


Asunto(s)
Angiografía con Fluoresceína/métodos , Oclusión de la Arteria Retiniana/diagnóstico , Arteria Retiniana/fisiopatología , Vasoconstricción , Fondo de Ojo , Humanos , Masculino , Persona de Mediana Edad , Arteria Retiniana/diagnóstico por imagen , Oclusión de la Arteria Retiniana/etiología
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