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Omnichannel environments where customers shop online and offline at the same retailer are ubiquitous, and are deployed by online-first and traditional retailers alike. We focus on the relatively understudied domain of online-first retailers and the engagement of a key omnichannel tactic; specifically, introduction of showrooms (physical locations where customers can view and try products) in combination with online fulfillment that uses centralized inventory management. We ask whether, and if so, how, showrooms benefit the two most basic retail objectives: demand generation and operational efficiency. Using quasi-experimental data on showroom openings by WarbyParker.com , the leading and iconic online-first eyewear retailer, we find that showrooms: (1) increase demand overall and in the online channel as well; (2) generate operational spillovers to the other channels by attracting customers who, on average, have a higher cost-to-serve; (3) improve overall operational efficiency by increasing conversion in a sampling channel and by decreasing returns; and (4) amplify these demand and operational benefits in dealing with customers who have the most acute need for the firm’s products. Moreover, the effects we document strengthen with time as showrooms contribute not only to brand awareness but also to what we term channel awareness as well. We conclude by elaborating the underlying customer dynamics driving our findings and by offering implications for how online-first retailers might deploy omnichannel tactics. This paper was accepted by Vishal Gaur, operations management.

Nucleic acid aptamers hold great promise for therapeutic applications due to their favorable intrinsic properties, as well as highthroughput experimental selection techniques. Despite the utility of the systematic evolution of ligands by the exponential enrichment (SELEX) method for aptamer determination, complementary in silico aptamer design is highly sought after to facilitate virtual screening and increased understanding of important nucleic acid–protein interactions. Here, with a combined experimental and theoretical approach, we have developed two optimal epithelial cellular adhesion molecule (EpCAM) aptamers. Our structure-based in silico method first predicts their binding modes and then optimizes them for EpCAM with molecular dynamics simulations, docking, and free energy calculations. Our isothermal titration calorimetry experiments further confirm that the EpCAM aptamers indeed exhibit enhanced affinity over a previously patented nanomolar aptamer, EP23. Moreover, our study suggests that EP23 and the de novo designed aptamers primarily bind to EpCAM dimers (and not monomers, as hypothesized in previous published works), suggesting a paradigm for developing EpCAM-targeted therapies.

Purpose Fear of reinjury is an important factor in determining who returns to sport following anterior cruciate ligament reconstruction (ACLR). Evidence from other musculoskeletal injuries indicates fear of reinjury may be related to stiffened movement patterns observed in individuals following ACLR. The relationship between fear of reinjury and performance on dynamic tasks, however, has not been investigated. Therefore, the purpose of this study was to investigate the relationship between fear of reinjury and jump-landing biomechanics. Methods Thirty-six females (height = 168.7 ± 6.5 cm, body mass = 67.2 ± 10.0 kg, age = 18.9 ± 1.5 years) with a history of ACLR (time from surgery = 26.1 ± 13.3 months) participated in the study. Each participant performed five trials of a standard jump-landing task. 3D motion capture and surface electromyography was used to record peak kinematics and lower extremity muscle activation on the injured limb during the jump landings. Spearman’s rank correlations established the relationship between TSK-11 scores and each biomechanical variable of interest. Results There was a significant, negative relationship between fear of reinjury (TSK-11: 19.9 ± 4.5) and knee ( p  = 0.006), hip ( p  = 0.003), and trunk flexion ( p  = 0.013). There was also a significant, positive relationship between hip adduction ( p  = 0.007), and gluteus maximus preparatory activation ( p  = 0.001). Conclusions The results of this study indicate that higher fear of reinjury is associated with stiffened movement patterns that are associated with increased risk of a second ACL injury. Similar movement patterns have been observed in patients with low back pain. Clinicians should evaluate psychological and emotional consequences of injury in addition to the physical consequences as they appear to be related. Level of evidence III.

Mantle separation Cratons, the ancient cores of continents, extend laterally for hundreds of kilometres, and are underlain to depths of 180 km to 250 km by mantle roots that are chemically and physically distinct from the surrounding mantle. But how these large portions of the mantle can stay isolated for so long from mantle convection has remained an open question. Anne Peslier and colleagues show that olivine components in peridotite xenoliths from the lithosphere–asthenosphere boundary region of the Kaapvaal Craton mantle root are water-poor, thereby providing sufficient viscosity contrast with the underlying asthenosphere to explain how they have resisted recycling into Earth's mantle. Cratons, the ancient cores of continents, extend laterally for hundreds of kilometres, and are underlain to depths of 180–250 km by mantle roots that are chemically and physically distinct from surrounding mantle. But how can these roots stay so isolated from mantle convection? Here it is shown that olivine in peridotite xenoliths from the lithosphere–athenosphere boundary region of the Kaapvaal craton mantle root is water-poor, providing sufficient viscosity contrast with the underlying asthenosphere to explain the root's stability. Cratons, the ancient cores of continents, contain the oldest crust and mantle on the Earth (>2 Gyr old) 1 . They extend laterally for hundreds of kilometres, and are underlain to depths of 180–250 km by mantle roots that are chemically and physically distinct from the surrounding mantle 2 , 3 , 4 . Forming the thickest lithosphere on our planet, they act as rigid keels isolated from the flowing asthenosphere 5 ; however, it has remained an open question how these large portions of the mantle can stay isolated for so long from mantle convection. Key physical properties thought to contribute to this longevity include chemical buoyancy due to high degrees of melt-depletion and the stiffness imparted by the low temperatures of a conductive thermal gradient 2 , 6 , 7 . Geodynamic calculations, however, suggest that these characteristics are not sufficient to prevent the lithospheric mantle from being entrained during mantle convection over billions of years 6 , 7 . Differences in water content are a potential source of additional viscosity contrast between cratonic roots and ambient mantle owing to the well-established hydrolytic weakening effect in olivine 8 , 9 , 10 , the most abundant mineral of the upper mantle. However, the water contents of cratonic mantle roots have to date been poorly constrained. Here we show that olivine in peridotite xenoliths from the lithosphere–asthenosphere boundary region of the Kaapvaal craton mantle root are water-poor and provide sufficient viscosity contrast with underlying asthenosphere to satisfy the stability criteria required by geodynamic calculations 9 . Our results provide a solution to a puzzling mystery of plate tectonics, namely why the oldest continents, in contrast to short-lived oceanic plates, have resisted recycling into the interior of our tectonically dynamic planet.

The adsorption of proteins onto carbon-based nanomaterials (CBNs) is dictated by hydrophobic and π-π interactions between aliphatic and aromatic residues and the conjugated CBN surface. Accordingly, protein adsorption is highly sensitive to topological constraints imposed by CBN surface structure; in particular, adsorption capacity is thought to increase as the incident surface curvature decreases. In this work, we couple Molecular Dynamics (MD) simulations with fluorescence spectroscopy experiments to characterize this curvature dependence in detail for the model protein bovine serum albumin (BSA). By studying BSA adsorption onto carbon nanotubes of increasing radius (featuring descending local curvatures) and a flat graphene sheet, we confirm that adsorption capacity is indeed enhanced on flatter surfaces. Naïve fluorescence experiments featuring multi-walled carbon nanotubes (MWCNTs), however, conform to an opposing trend. To reconcile these observations, we conduct additional MD simulations with MWCNTs that match those prepared in experiments; such simulations indicate that increased mass to surface area ratios in multi-walled systems explain the observed discrepancies. In reduction, our work substantiates the inverse relationship between protein adsorption capacity and surface curvature and further demonstrates the need for subtle consideration in experimental and simulation design.

In spring 2020, schools closed to in-person teaching and sports were cancelled to control the transmission of COVID-19. The changes that affected the physical and mental health among young athletes during this time remain unknown. To identify changes in the health (mental health, physical activity, and quality of life) of athletes that occurred during the COVID-19 pandemic. Cross-sectional study. Sample recruited via social media. A total of 3243 Wisconsin adolescent athletes (age = 16.2 ± 1.2 years, 58% female) were surveyed in May 2020 (During COVID-19). Measures for this cohort were compared with previously reported data for Wisconsin adolescent athletes (n = 5231; age = 15.7 ± 1.2 years, 47% female) collected in 2016 to 2018 (PreCOVID-19). Demographic information included sex, grade, and sport(s) played. Health assessments included the Patient Health Questionnaire-9 Item to identify depression symptoms, the Pediatric Functional Activity Brief Scale to gauge physical activity, and the Pediatric Quality of Life Inventory 4.0 to evaluate health-related quality of life. Univariable comparisons of these variables between groups were conducted via t or χ2 tests. Means and 95% CIs for each group were estimated using survey-weighted analysis-of-variance models. Compared with preCOVID-19 participants, a larger proportion of During COVID-19 participants reported moderate to severe levels of depression (9.7% versus 32.9%, P < .001). Scores of the During COVID-19 participants were 50% lower (worse) on the Pediatric Functional Activity Brief Scale (mean [95% CI] = 12.2 [11.9, 12.5] versus 24.7 [24.5, 24.9], P < .001) and the Pediatric Quality of Life Inventory 4.0 compared with the PreCOVID-19 participants (78.4 [78.0, 78.8] versus 90.9 [90.5, 91.3], P < .001). During the COVID-19 pandemic, adolescent athletes described increased symptoms of depression, decreased physical activity, and decreased quality of life compared with adolescent athletes in previous years.

During the fall of 2020, some high schools across the United States allowed their students to participate in interscholastic sports while others cancelled or postponed their sport programs due to concerns regarding COVID-19 transmission. What effect this has had on the physical and mental health of adolescents is unknown. To identify the effect of playing a sport during the COVID-19 pandemic on the health of student-athletes. Cross-sectional study. Sample recruited via email. A total of 559 Wisconsin high school athletes (age = 15.7 ± 1.2 years, female = 43.6%, male = 56.4%) from 44 high schools completed an online survey in October 2020. A total of 171 (30.6%) athletes played (PLY) a fall sport, while 388 (69.4%) did not play (DNP). Demographic data included sex, grade, and sport(s) played. Assessments were the General Anxiety Disorder-7 Item for anxiety, Patient Health Questionnaire-9 Item for depression, the Hospital for Special Surgery Pediatric Functional Activity Brief Scale for physical activity, and the Pediatric Quality of Life Inventory 4.0 for quality of life. Univariable comparisons between the 2 groups were made via t tests or χ2 tests. Means for each continuous outcome measure were compared between groups using analysis-of-variance models that controlled for age, sex, teaching method (virtual, hybrid, or in person), and the percentage of students eligible for free or reduced-price lunch. The PLY group participants were less likely to report moderate to severe symptoms of anxiety (PLY = 6.6%, DNP = 44.1%, P < .001) and depression (PLY = 18.2%, DNP = 40.4%, P < .001). They also demonstrated higher (better) Pediatric Functional Activity Brief Scale scores (PLY = 23.2 [95% CI = 22.0, 24.5], DNP = 16.4 [95% CI = 15.0, 17.8], P < .001) and higher (better) Pediatric Quality of Life Inventory total scores (PLY = 88.4 [95% CI = 85.9, 90.9], DNP = 79.6 [95% CI = 76.8, 82.4], P < .001). Adolescents who played a sport during the COVID-19 pandemic described fewer symptoms of anxiety and depression and had better physical activity and quality-of-life scores compared with adolescent athletes who did not play a sport.

Purpose To determine possible differences in single-hop kinematics and kinetics in females with anterior cruciate ligament reconstruction compared to healthy controls. A second purpose was to make comparisons between the healthy and reconstructed limbs. Methods Subjects were grouped based on surgical status (33 ACLR patients and 31 healthy controls). 3D motion capture synchronized with force plates was used to capture the landing phase of three successful trials of single hop for distance during a single data collection session. Peak values during the loading phase were analysed. Subjects additionally completed three successful trials of the triple hop for distance Tegner activity scale and International Knee Document Committee 2000 (IKDC). Results Controls demonstrated greater peak knee flexion and greater internal knee extension moment and hip extension moment than ACLR subjects. Within the ACLR group, the healthy limb exhibited greater peak knee flexion, hip flexion, hip extension moment, single hop and triple hops for distance and normalized quadriceps strength. Conclusion Patients who undergo anterior cruciate ligament reconstruction land in a more extended posture when compared to healthy controls and compared to their healthy limb. Level of evidence III.