Influence of Taper surface topographies on contact deformation and stresses.

The role of bore and trunnion surface topography on the failure rate of total hip joint replacements due to trunnionosis is not clear despite significant variations in the design of taper components between manufacturers. Taper surface topography, along with other taper design parameters such as clearance, diameter, and assembly force, determine the initial interlock of the contacting surfaces after assembly; this has been related to relative motions that can cause fretting and corrosion at the taper interface. However, in most in-silico parametrical taper studies associated with taper micromotions, the bore and trunnion surfaces have been simplified using a flat surface and/or sinusoidal functions to mimic the surface roughness. The current study tests the hypothesis that the use of simple geometrical functions for the taper surface topography can predict the surface mechanics developed in assembled tapers. Measured and simulated surfaces of bores and trunnions were characterised using common roughness parameters and spectral density estimations. Using the same characterised surface profiles, 2D Finite Element (FE) models of CoCr alloy femoral heads and Ti alloy trunnions were developed. Models simulated assembly conditions at different resultant forces ranging from 0.5 to 4.0 kN, contact conditions were determined and associated with their topographical characteristics. Measured surfaces of bore and trunnion components comprise up to seven dominant spatial frequencies. Flattening of the trunnion microgrooved peaks was observed during the assembly of the taper. When the femoral head bore and trunnion topography were both considered a reduced number of microgrooved peaks were in contact, from 51 in an idealised taper surfaces to 35 in measured surfaces using an assembly reaction force of 4 kN. The contact points in the models developed high plastic strains, which were greater than that associated with failure of the material. Results showed that line and sine wave functions over estimate contact points at the taper interface compared to those surfaces that consider roughness and peak variation. These findings highlight the important role of modelling the full surface topography on the taper contact mechanics, as surface variations in the roughness and waviness change the performance of tapers.

Performance of the adaptive optics system for Laser Communications Relay Demonstration's Ground Station 1.

The Laser Communications Relay Demonstration is NASA's multi-year demonstration of laser communication from the Earth to a geosynchronous satellite. The mission currently has two optical ground stations (OGSs), with one in California (OGS1) and one in Hawaii (OGS2). Each ground terminal optical system consists of a high-order adaptive optics (AO) system, a laser transmit system, and a camera for target acquisition. The OGS1 AO system is responsible for compensating for the downlink beam for atmospheric turbulence and coupling it into the modem's single mode fiber. The mission requires a coupling efficiency of 50%, which necessitates a high-order AO system. To achieve this performance, the AO system uses two deformable mirrors with one mirror correcting for low-spatial-frequency aberrations with large amplitude and a second deformable mirror correcting for high-spatial-frequency aberrations with small amplitude. Turbulence is sensed with a Shack-Hartmann wavefront sensor. To meet its performance requirements in the most stressing conditions, the system can operate at frame rates of 20 kHz. This high frame rate is enabled by the design of the real-time control system. We present an overview of both the hardware and software design of the system, and describe the control system and methods of reducing non-common path aberrations. Finally, we show measured system performance.

Exercise knowledge, barriers and motivators among LRRK2 G2019S mutation carriers.

INTRODUCTION: People with a Gly2019Ser mutation in the leucine-rich repeat kinase 2 (LRRK2 G2019S) are at increased risk of developing Parkinson's disease (PD). Recent evidence suggests that exercise may delay or prevent the development of clinically overt symptoms of PD in people at risk of PD. We determined whether LRRK2 G2019S mutation carriers with and without manifest PD are aware of the relationship between exercise and PD and how they differ in awareness, barriers and motivators to exercise. METHODS: We deployed a survey among 4422 LRRK2 G2019S mutation carriers. In total, 505 (11.4%) of them completed the survey, of whom 105 had self-reported manifest PD. RESULTS: Ninety-two percent of the LRRK2 G2019S mutation carriers with manifest PD and 63% of those with non-manifest PD were aware of the relationship between exercise and PD. Lack of motivation was the top barrier for those without manifest PD, while having an injury/disability was the most common barrier for those with manifest PD. Improvement of body functioning was the top motivator for both. CONCLUSION: The fact that many at-risk individuals are not aware of the importance of exercise and would exercise more with fewer barriers creates opportunities for trials using exercise as a possible prevention strategy for PD.

Responsiveness in interracial interactions.

Perceived responsiveness-feeling understood, validated, and cared for-is critical for wellbeing and successful relationships, yet these feelings are experienced less frequently in interracial interactions than in same race-interactions. In this article, we synthesize recent research on responsiveness in interracial interactions and relationships. We first highlight how responsiveness differs in interracial versus same-race contexts. We next discuss the role of cross-race partners' goals and motivations in responsiveness, with particular attention to the ways in which self-presentation goals undermine responsiveness as well as emerging research on goals and motivations that may facilitate responsiveness in interracial interactions. Finally, we discuss how a contextual factor, the salience of race, influences responsiveness in interracial interactions.

Ultrafast Charge Injection in Silver-Modified Graphitic Carbon Nitride.

Graphitic carbon nitride (gCN) is a promising organic platform for driving light-activated charge-transfer reactions in a number of valuable photocatalytic cycles. A primary limitation of gCN as a photocatalyst is its short excited-state lifetime, which is mediated by a high density of trap and defect sites that result in rapid excited-state decay and low photocatalytic efficiency. To enhance the catalytic activity, gCN is often functionalized with a metal co-catalyst; however, the mechanism by which metal co-catalysts enhance the reactivity has not been clearly established. In this work, the excited-state dynamics of gCN and silver-modified gCN are compared using ultrafast transient absorption and time-resolved photoluminescence spectroscopies. In silver-modified gCN, an ultrafast spectral shift in the silver plasmon resonance provides direct spectral evidence of electron transfer from gCN to the silver nanoparticles. The electron-transfer rate is competitive with other non-radiative relaxation pathways, with electron-transfer yields approaching 50%, thus providing an effective strategy for mitigating losses associated with defects and trap sites.

Influence of taper design and loading on taper micromotion.

Debris originating at the bore-trunnion interface of modular total hip replacements has been identified as one of the causes of hip replacements failure. Friction associated with fretting and corrosion represents a potential generator of these harmful particles. Understanding the motions at the interface will help to interpret the different damage patterns found in retrieval studies and minimize the risk of fluid ingress/egress into the taper interface. Accordingly, the present study is designed to characterise the nature of the relative motions generated at the bore-trunnion interface of different taper designs during typical loading profiles. 3D Finite Element (FE) models of a CoCr femoral head assembled onto a Ti alloy trunnion were generated and variables including taper clearance, deviation from roundness, assembly force and loading conditions were introduced. Resulting micromotions relative to the trunnion surface, separation and contact area of the bore-trunnion interface were shown to be affected by both taper design and types of activities. Results indicated that, in some cases, the largest component of motion corresponded to that developed normal to the trunnion surface. Furthermore, out of roundness as small as 6 µm across the diameter, in particular orientations, significantly changed the contact mechanics and magnitude of relative motions. From the resulting parameters at the bore-trunnion interface, a pump type of motion was identified during walking, jogging and stairs up activities. The components of relative motions at the bore-trunnion interface were found to be different regardless of the resultant magnitude of the relative motions. The findings highlight the importance of high-quality manufacturing processes as small changes in the trunnion component will significantly affect the clinical performance of this common type of modular approach in total hip replacements.

Total hip arthroplasty in Cambodia - Our experience of two hundred and fifty six consecutive total hip arthroplasties in a low-income country & the challenge of service delivery in this setting.

The Children's Surgical Centre has performed 256 THAs since 2007, We aim to assess the outcome of arthroplasty in a LMIC. Primary outcome: all cause of re-operation, Secondary outcome: any other complication. A retrospective review of all consecutive THA since 2007 was conducted. Electronic and physical case notes were reviewed. Statistical analysis was performed using MedCalc. 256 THA. Mean age: 43, gender M2:1F. Common pathologies include (1) AVN (44%), (2) OA (11%) and (3) DDH (11%). Revision rate 13%. Time to revision was 2.8 years (0-9). Common revision reasons: (1) stem fracture (5.8%), (2) aseptic loosening (4.8%) and (3) infection (2.7%). Complications were identified in 85 patients (33.2%). Common complications included (1) aseptic loosening (10.5%) (2) stem fracture (5.8%) and (3) dislocation (5.8%). Patients at CSC benefit from THA, the complication rates at CSC are declining suggesting the apex of the 'learning curve' has passed. Cheap poorly manufactured implants continue to cause catastrophic failure.

Photocatalytic Reduction of Aqueous Nitrate with Hybrid Ag/g-C3N4 under Ultraviolet and Visible Light.

The concentration of nitrate in natural surface waters by agricultural runoff remains a challenging problem in environmental chemistry. One promising denitrification strategy is to utilize photocatalysts, whose light-driven excited states are capable of reducing nitrate to nitrogen gas. We have synthesized and characterized pristine and silver-loaded graphitic carbon nitrides and assessed their activity for photocatalytic nitrate reduction at neutral pH. While nitrate reduction does occur on the pristine material, the silver cocatalyst greatly enhances product yields. Kinetic studies performed in batch photoreactors under both UV and visible excitation suggest that nitrate reduction to produce aqueous nitrite, ammonium, and nitrogen gas proceeds via a cooperative water reduction on the silver metal domains to produce adsorbed H atoms. By varying the percentage of silver loading onto the g-C3N4, the density of metal domains can be adjusted, which in turn tunes the reduction selectivity toward various products.

A Case Report: Hepatic artery pseudoaneurysm causing life-threatening haemobilia.

INTRODUCTION & IMPORTANCE: Hepatic artery aneurysms (HAA) are rare and it accounts 20% of all visceral artery aneurysms. Commonly HAAs are autopsy findings, but rupture and bleeding carrying significant morbidity and can manifest as haemobilia. CASE PRESENTATION: A 63-year-old Sri Lankan male presented with severe melaena upper abdominal pain and features of obstructive jaundice was found to have a giant pseudoaneurysm at the right hepatic artery with the possible arterio-biliary fistula. The etiology for the pseudoaneurysm was not identified. Despite massive transfusion, the patient died before the endovascular intervention. CLINICAL DISCUSSION: Atherosclerosis is the leading cause of HAA formation but can be associated with connective tissue disorders and arteritis. Most of the HAA are asymptomatic. Aneurysms can be managed with surgical or endovascular interventions. CONCLUSION: Life-threatening haemobilia is a notorious complication of the rapture of HAA into the biliary system. The incidents of hepatic artery aneurysms and pseudoaneurysms due to percutaneous transhepatic interventions and minimal invasive hepatobiliary surgeries are in the rising trend. Nonleaking VAA can be best treated with endovascular treatment. The knowledge on this topic is important for the early detection and intervention of this rare entity.

Beyond students: how teacher psychology shapes educational inequality.

Although researchers investigating psychological contributors to educational inequality have traditionally focused on students, a growing literature highlights the importance of teachers' psychology in shaping disparities in students' educational achievement and attainment. In this review, we discuss recent advances linking teachers' attitudes, perceptions, and beliefs to inequality in students' outcomes. First, we identify specific aspects of teacher psychology that contribute to educational disparities, including teachers' biases, perceptions and expectations of students, beliefs about the nature of ability, and beliefs about group differences. Second, we synthesize mechanisms underlying the effects of teacher psychology on educational inequality, including teachers' disparate assessment of students' work and abilities, interpersonal interaction with students, and psychological impact on students. Implications for future research and interventions are discussed.

How university diversity rationales inform student preferences and outcomes.

It is currently commonplace for institutions of higher education to proclaim to embrace diversity and inclusion. Though there are numerous rationales available for doing so, US Supreme Court decisions have consistently favored rationales which assert that diversity provides compelling educational benefits and is thus instrumentally useful. Our research is a quantitative/experimental effort to examine how such instrumental rationales comport with the preferences of White and Black Americans, specifically contrasting them with previously dominant moral rationales that embrace diversity as a matter of intrinsic values (e.g., justice). Furthermore, we investigate the prevalence of instrumental diversity rationales in the American higher education landscape and the degree to which they correspond with educational outcomes. Across six experiments, we showed that instrumental rationales correspond to the preferences of White (but not Black) Americans, and both parents and admissions staff expect Black students to fare worse at universities that endorse them. We coded university websites and surveyed admissions staff to determine that, nevertheless, instrumental diversity rationales are more prevalent than moral ones are and that they are indeed associated with increasing White-Black graduation disparities, particularly among universities with low levels of moral rationale use. These findings indicate that the most common rationale for supporting diversity in American higher education accords with the preferences of, and better relative outcomes for, White Americans over low-status racial minorities. The rationales behind universities' embrace of diversity have nonlegal consequences that should be considered in institutional decision making.

Are There Regional Differences in Triple Negative Breast Cancer among Non-Hispanic Black Women?

BACKGROUND: Non-Hispanic black women (NHB) are diagnosed with triple negative breast cancer (TNBC) more often than other ethnic or racial groups in the United States (US). This study describes regional differences in TNBC incidence among NHB women in the US from 2011 to 2015. METHODS: We analyzed data from the United States Cancer Statistics (USCS) that includes incidence data from the Centers for Disease Control and Prevention's National Program of Cancer Registries (NPCR) and the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) programs. RESULTS: Compared to the incidence rate for NHB women in the South, rates were significantly lower in the Northeast (22.6 per 100,000), higher in the Midwest (25.5 per 100,000) and similar in the West. These regional differences might be explained by genetic admixture among people with different geographic ancestral origins. CONCLUSIONS: Results from this study highlight the need to extend etiological research and evidence-based cancer prevention and control efforts to women at high risk of this disease in order to decrease cancer disparities.

Characteristics of Participants in the American Urological Association Quality (AQUA) Registry and Early Impact of Participation on Quality of Care.

INTRODUCTION: The American Urological Association Quality Registry (AQUA) is an approved Qualified Clinical Data Repository that was created in 2013 to serve as a platform of quality assessment and improvement. Little is known about how such specialty specific platforms are adopted and used. We describe AQUA participants and report early impact on quality metrics. METHODS: We compared characteristics of practices and urologists participating in AQUA from 2014-2017 to those of the broader urologist workforce as reported in the 2017 American Urological Association Census, and examined pass rates of 4 measures reported to the Centers for Medicare and Medicaid Services after participation in AQUA. RESULTS: Participation increased during the first 4 years and included >125 practices and 1,148 urologists (9.2% of practicing U.S. urologists). Of AQUA participants 97.6% were in private practice, 1.9% were in academic practice and the rest (0.5%) were employed by private or public hospitals, compared to 59.1%, 25.5% and 11.2%, respectively, of urologists nationally. Among AQUA participants 95.9% lived in metropolitan areas, compared to 89.9% of urologists nationally. A total of 17 quality measures were reported to the Centers for Medicare and Medicaid Services through AQUA, of which 4 were urology specific and 13 were crosscutting. The average pass rate across the 4 select urological measures was 31.1% prior to AQUA dashboard access and 48.8% after access was gained, a 56.9% improvement (17.1% absolute difference). CONCLUSIONS: Early participants in AQUA were mostly community practitioners. Participation in AQUA seemed to facilitate quality score improvements, although whether this was due to improved measurement vs clinical care is unknown at this time.

Heated Air Delivery by Micro-Sauna: An Experimental Treatment Prototype Concept for Coronavirus Disease 2019.

Coronavirus disease 2019 (COVID-19) has gained international attention as it poses a significant threat to global health. Currently, medical researchers are working to exhaust all strategies that may prove beneficial in combating this disease. Heat has been shown to destabilize other coronavirus strains in testing environments, and it has been hypothesized that heated air may destabilize viral pathogens in vivo as well. The present report describes the engineering of a micro-sauna prototype for the delivery of heated air. Concept formulation, process highlights, and the final prototype are all discussed. The prototype can deliver air heated to 80-90 degrees Celsius in a safe and tolerable manner. The goal of this technical report is to further encourage the study of heated air as a potential COVID-19 treatment.

Are uninsured women in a national screening program having longer intervals between cervical cancer screening tests?

With increased understanding of the natural history of cervical cancer, cervical cancer screening recommendations have evolved (Schiffman & Wentzensen, 2013). As research better quantified the balance of benefits and harms of screening, new recommendations called for longer intervals between screening tests. Adherence to longer screening intervals detects similar numbers of abnormalities and decreases harms associated with overscreening/overtreatment. In this descriptive study, we examined the cervical cancer screening intervals from 2010 to 2018 in the National Breast and Cervical Cancer Early Detection Program (NBCCEDP). There were 1,397,899 women aged 21-64 who were screened for cervical cancer from 2010 to 2018 and 556,743 rescreenings of average risk women were performed. The median cervical screening interval increased from 2.02 years in 2010 to 3.88 years in 2018. Providers serving uninsured women in a national screening program are following the recommendations of longer intervals between cervical cancer screenings.

Diffusion doping of cobalt in rod-shape anatase TiO2 nanocrystals leads to antiferromagnetism.

Cobalt(ii) ions were adsorbed to the surface of rod-shape anatase TiO2 nanocrystals and subsequently heated to promote ion diffusion into the nanocrystal. After removal of any remaining surface bound cobalt, a sample consisting of strictly cobalt-doped TiO2 was obtained and characterized with powder X-ray diffraction, transmission electron microscopy, UV-visible spectroscopy, fluorescence spectroscopy, X-ray photoelectron spectroscopy, SQUID magnetometry, and inductively-coupled plasma atomic emission spectroscopy. The nanocrystal morphology was unchanged in the process and no new crystal phases were detected. The concentration of cobalt in the doped samples linearly correlates with the initial loading of cobalt(ii) ions on the nanocrystal surface. Thin films of the cobalt doped TiO2 nanocrystals were prepared on indium-tin oxide coated glass substrate, and the electrical conductivity increased with the concentration of doped cobalt. Magnetic measurements of the cobalt-doped TiO2 nanocrystals reveal paramagnetic behavior at room temperature, and antiferromagnetic interactions between Co ions at low temperatures. Antiferromagnetism is atypical for cobalt-doped TiO2 nanocrystals, and is proposed to arise from interstitial doping that may be favored by the diffusional doping mechanism.

Search for Gamma-ray Emission from p-wave Dark Matter Annihilation in the Galactic Center.

Indirect searches for dark matter through Standard Model products of its annihilation generally assume a cross-section which is dominated by a term independent of velocity (s-wave annihilation). However, in many DM models an s-wave annihilation cross-section is absent or helicity suppressed. To reproduce the correct DM relic density in these models, the leading term in the cross section is proportional to the DM velocity squared (p-wave annihilation). Indirect detection of such p-wave DM is difficult because the average velocities of DM in galaxies today are orders of magnitude slower than the DM velocity at the time of decoupling from the primordial thermal plasma, thus suppressing the annihilation cross-section today by some five orders of magnitude relative to its value at freeze out. Thus p-wave DM is out of reach of traditional searches for DM annihilations in the Galactic halo. Near the region of influence of a central supermassive black hole, such as Sgr A*, however, DM can form a localized over-density known as a "spike". In such spikes the DM is predicted to be both concentrated in space and accelerated to higher velocities, thereby allowing the γ-ray signature from its annihilation to potentially be detectable above the background. We use the Fermi Large Area Telescope to search for the γ-ray signature of p-wave annihilating DM from a spike around Sgr A* in the energy range 10 GeV-600 GeV. Such a signal would appear as a point source and would have a sharp line or box-like spectral features difficult to mimic with standard astrophysical processes, indicating a DM origin. We find no significant excess of γ rays in this range, and we place upper limits on the flux in γ-ray boxes originating from the Galactic Center. This result, the first of its kind, is interpreted in the context of different models of the DM density near Sgr A*.

Geographic variation in the use of lymphadenectomy and external-beam radiotherapy for endometrial cancer: a cross-sectional analysis of population-based data.

OBJECTIVE: To quantify geographic variation in the use of lymphadenectomy and/or external-beam radiotherapy (EBRT) for endometrial cancer in England. DESIGN: Cross-sectional analysis of population-based data. SETTING: English cancer registry data, linked to chemotherapy, radiotherapy and hospital episodes statistics data. POPULATION: Twenty-two thousand four hundred and eighty-three women with endometrial cancer presenting without clinical or radiological evidence of distant metastatic spread, diagnosed in England from 2013 to 2016. METHODS: Proportions of patients receiving lymphadenectomy and/or EBRT were compared across 19 Cancer Alliances, to identify variations in clinical practice. Two separate logistic regression models assessed the impact on variation of adjustment for tumour and patient characteristics. MAIN OUTCOME MEASURES: Receipt of lymphadenectomy, receipt of EBRT. RESULTS: There was substantial variation by Cancer Alliance in the adjusted proportion of women with endometrial cancer receiving lymphadenectomy (range 5% [95% CI 4-6%] to 48% [95% CI 45-52%]) and EBRT (range 10% [95% CI 7-12%] to 31% [95% CI 28-33%]), after adjusting for variation in pathological grade, age, comorbidities, deprivation, ethnic group and (EBRT only) FIGO stage. Different approaches to clinical practice were identified; (i) one Cancer Alliance had significantly higher than average lymphadenectomy and significantly lower than average EBRT use, (ii) three had high use of both lymphadenectomy and EBRT, (iii) one had low lymphadenectomy use and high EBRT use, and (iv) three had low use of both lymphadenectomy and EBRT. CONCLUSIONS: Lymphadenectomy is probably used to triage for EBRT when lymphadenectomy use is high and EBRT use is low. This is probably a result of variation in local endometrial cancer management guidelines, suggesting that UK recommendations should be clarified. TWEETABLE ABSTRACT: There is geographic variation in England in the use of lymphadenectomy and radiotherapy to treat endometrial cancer.