Fighting has been part of the fabric of the NHL for nearly a century. Recent sharp declines in the frequency of fighting and increased understanding of the long-term consequences of traumatic brain ...injuries have led many to question whether fighting still has a place in the modern NHL. League commissioner Gary Bettman as recently as 2019 testified before Canadian Parliament that fighting has a deterrent effect, reducing the overall level of violent and dangerous plays within the game. This study empirically examines this claim and tests whether fighting indeed serves as a deterrent to undesirable behaviors in the NHL. I examine data on all regular season penalties from 2010–2019 to determine whether fighting and the threat of fighting is empirically related the level of violence in NHL games. Using a mix of descriptive and quasi-experimental approaches, I find no quantifiable evidence that fighting serves as a deterrent to undesirable violent behaviors in the NHL. To the contrary, I find that teams and players who fight are responsible for a disproportionate amount of the violent penalties that happen across the league. These results have implications for player safety in the many professional—and especially junior—hockey leagues around the world that sanction in-game fighting.
Prospective study of the sagittal plane alignment of the spine and pelvis in the normal pediatric population.
To document the sagittal alignment of the spine and pelvis and its change during growth ...in the normal pediatric population.
Pelvic morphology as well as sagittal alignment of the spine and pelvis in the pediatric population are poorly defined in the literature.
Five parameters were evaluated on lateral standing radiographs of 180 normal study participants 4 to 18 years of age: thoracic kyphosis, lumbar lordosis, sacral slope, pelvic tilt, and pelvic incidence. Statistical analysis was performed using two-tailed Student t tests and Pearson's coefficients (level of significance = 0.01).
The mean thoracic kyphosis, lumbar lordosis, sacral slope, pelvic tilt, and pelvic incidence values were 43.0 degrees, 48.5 degrees, 41.2 degrees, 7.2 degrees and 48.4 degrees, respectively. There was no significant difference between males and females. Thoracic kyphosis, lumbar lordosis, pelvic tilt, and pelvic incidence were found to be weakly correlated with age, while sacral slope remained stable with growth.
Pelvic morphology, as measured by the pelvic incidence angle, tends to increase during childhood and adolescence before stabilizing into adulthood, most likely to maintain an adequate sagittal balance in view of the physiologic and morphologic changes occurring during growth. Pelvic tilt and lumbar lordosis, two position-dependent parameters, also react by increasing with age, most likely to avoid inadequate anterior displacement of the body center of gravity. Sacral slope is achieved with the standing posture and is not further significantly influenced by age. These results are important to establish baseline values for these measurements in the pediatric population, in view of the reported association between pelvic morphology and the development of various spinal disorders such as spondylolisthesis and scoliosis.
•Mechanisms of heat transfer enhancement at high pressure pool boiling.•Pressure changes the hydrodynamic behavior of bubbles, leads to change in the heat transfer performance.•Compared the ...experimental data with the existing models.•A need of theoretical model to capture the physics of high pressure pool boiling heat transfer.•Designed analysis of high pressure pool boiling experimental setup.
Pressure has a huge impact on the performance of pool boiling heat transfer due to the change in thermofluid properties of water. The specific volume of water and the latent heat of vaporization decrease with increasing system pressure. High pressure pool boiling experiments were conducted for water on a horizontal smoothed copper surface at pressures ranging from 0 psig (0 kPa) to 60 psig (413.7 kPa). The hydrodynamic behavior of bubbles was studied at high pressure using the flow visualization technique. The primary bubble size, detachment frequencies, and nucleation site densities were studied at each pressure. The performance of the pool boiling curve was critically analyzed with different predictive models. To compare the pressure data and validate with the existing model, Stephan and Abdelsalam’s model was used. At low heat flux, no changes in the heat transfer coefficient were noticed. At high flux, a 50%, 75%, 125%, and 175% enhancement in the heat transfer coefficient was found against the atmospheric pressure (0 kPa) for 15 psig (103.4 kPa), 30 psig (206.8 kPa), 45 psig (310.2 kPa), and 60 psig (413.7 kPa) respectively. The critical heat flux value was also measured and compared to the predicted theories. A new mechanistic lift model, similar to the Zuber’s model, was used to explain the dry out mechanisms at high pressure in which pressure delays the surface dry out behavior. The results show that change in thermodynamic properties of water due to pressure not only change the hydrodynamic behavior, but also impacts the formation of the thermal boundary layer. The present study shows that there is a need for a theoretical model to predict the critical heat flux and the heat transfer coefficient at high pressure. At high pressure the contact angle shows a dynamic behavior due to change in the surface tension of liquid. The current research work aims to be a fundamental ground to develop for manufactures/designers of high pressurized boilers.
Develop recommendations for women's health issues and family planning in systemic lupus erythematosus (SLE) and/or antiphospholipid syndrome (APS).
Systematic review of evidence followed by modified ...Delphi method to compile questions, elicit expert opinions and reach consensus.
Family planning should be discussed as early as possible after diagnosis. Most women can have successful pregnancies and measures can be taken to reduce the risks of adverse maternal or fetal outcomes. Risk stratification includes disease activity, autoantibody profile, previous vascular and pregnancy morbidity, hypertension and the use of drugs (emphasis on benefits from hydroxychloroquine and antiplatelets/anticoagulants). Hormonal contraception and menopause replacement therapy can be used in patients with stable/inactive disease and low risk of thrombosis. Fertility preservation with gonadotropin-releasing hormone analogues should be considered prior to the use of alkylating agents. Assisted reproduction techniques can be safely used in patients with stable/inactive disease; patients with positive antiphospholipid antibodies/APS should receive anticoagulation and/or low-dose aspirin. Assessment of disease activity, renal function and serological markers is important for diagnosing disease flares and monitoring for obstetrical adverse outcomes. Fetal monitoring includes Doppler ultrasonography and fetal biometry, particularly in the third trimester, to screen for placental insufficiency and small for gestational age fetuses. Screening for gynaecological malignancies is similar to the general population, with increased vigilance for cervical premalignant lesions if exposed to immunosuppressive drugs. Human papillomavirus immunisation can be used in women with stable/inactive disease.
Recommendations for women's health issues in SLE and/or APS were developed using an evidence-based approach followed by expert consensus.
Randomized controlled trial with single-blinded primary outcome assessment.
To determine the efficacy and safety of autologous incubated macrophage treatment for improving neurological outcome in ...patients with acute, complete spinal cord injury (SCI).
Six SCI treatment centers in the United States and Israel.
Participants with traumatic complete SCI between C5 motor and T11 neurological levels who could receive macrophage therapy within 14 days of injury were randomly assigned in a 2:1 ratio to the treatment (autologous incubated macrophages) or control (standard of care) groups. Treatment group participants underwent macrophage injection into the caudal boundary of the SCI. The primary outcome measure was American Spinal Injury Association (ASIA) Impairment Scale (AIS) A-B or better at ≥6 months. Safety was assessed by analysis of adverse events (AEs).
Of 43 participants (26 treatment, 17 control) having sufficient data for efficacy analysis, AIS A to B or better conversion was experienced by 7 treatment and 10 control participants; AIS A to C conversion was experienced by 2 treatment and 2 control participants. The primary outcome analysis for subjects with at least 6 months follow-up showed a trend favoring the control group that did not achieve statistical significance (P=0.053). The mean number of AEs reported per participant was not significantly different between the groups (P=0.942).
The analysis failed to show a significant difference in primary outcome between the two groups. The study results do not support treatment of acute complete SCI with autologous incubated macrophage therapy as specified in this protocol.
Pregnancy constitutes a major challenge to the maternal immune system, as it has to tolerate the persistence of paternal alloantigen. Although localized mechanisms contribute to fetal evasion from ...immune attack, maternal alloreactive lymphocytes persist. We demonstrate here an alloantigen-independent, systemic expansion of the maternal CD25+ T cell pool during pregnancy and show that this population contains dominant regulatory T cell activity. In addition to their function in suppressing autoimmune responses, maternal regulatory T cells suppressed an aggressive allogeneic response directed against the fetus. Their absence led to a failure of gestation due to immunological rejection of the fetus.
Hearing impairment (HI) is highly prevalent in older adults and is associated with social isolation, depression, and risk of dementia. Whether HI is associated with broader downstream outcomes is ...unclear. We undertook this study to determine whether audiometric HI is associated with mortality in older adults.
Prospective observational data from 1,958 adults ≥70 years of age from the Health, Aging, and Body Composition Study were analyzed using Cox proportional hazards regression. Participants were followed for 8 years after audiometric examination. Mortality was adjudicated by obtaining death certificates. Hearing was defined as the pure-tone average of hearing thresholds in decibels re: hearing level (dB HL) at frequencies from 0.5 to 4kHz. HI was defined as pure-tone average >25 dB HL in the better ear.
Of the 1,146 participants with HI, 492 (42.9%) died compared with 255 (31.4%) of the 812 with normal hearing (odds ratio = 1.64, 95% CI: 1.36-1.98). After adjustment for demographics and cardiovascular risk factors, HI was associated with a 20% increased mortality risk compared with normal hearing (hazard ratio = 1.20, 95% CI: 1.03-1.41). Confirmatory analyses treating HI as a continuous predictor yielded similar results, demonstrating a nonlinear increase in mortality risk with increasing HI (hazard ratio = 1.14, 95% CI: 1.00-1.29 per 10 dB of threshold elevation up to 35 dB HL).
HI in older adults is associated with increased mortality, independent of demographics and cardiovascular risk factors. Further research is necessary to understand the basis of this association and whether these pathways might be amenable to hearing rehabilitation.
G protein-coupled receptors (GPCRs) have evolved to recognize incredibly diverse extracellular ligands while sharing a common architecture and structurally conserved intracellular signaling partners. ...It remains unclear how binding of diverse ligands brings about GPCR activation, the common structural change that enables intracellular signaling. Here, we identify highly conserved networks of water-mediated interactions that play a central role in activation. Using atomic-level simulations of diverse GPCRs, we show that most of the water molecules in GPCR crystal structures are highly mobile. Several water molecules near the G protein-coupling interface, however, are stable. These water molecules form two kinds of polar networks that are conserved across diverse GPCRs: (i) a network that is maintained across the inactive and the active states and (ii) a network that rearranges upon activation. Comparative analysis of GPCR crystal structures independently confirms the striking conservation of water-mediated interaction networks. These conserved water-mediated interactions near the G protein-coupling region, along with diverse water-mediated interactions with extracellular ligands, have direct implications for structure-based drug design and GPCR engineering.
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