Nanoscale Electronic Transparency of Wafer-Scale Hexagonal Boron Nitride.

Monolayer hexagonal boron nitride (hBN) has attracted interest as an ultrathin tunnel barrier or environmental protection layer. Recently, wafer-scale hBN growth on Cu(111) was developed for semiconductor chip applications. For basic research and technology, understanding how hBN perturbs underlying electronically active layers is critical. Encouragingly, hBN/Cu(111) has been shown to preserve the Cu(111) surface state (SS), but it was unknown how tunneling into this SS through hBN varies spatially. Here, we demonstrate that the Cu(111) SS under wafer-scale hBN is homogeneous in energy and spectral weight over nanometer length scales and across atomic terraces. In contrast, a new spectral feature─not seen on bare Cu(111)─varies with atomic registry and shares the spatial periodicity of the hBN/Cu(111) moiré. This work demonstrates that, for some 2D electron systems, an hBN overlayer can act as a protective yet remarkably transparent window on fragile low-energy electronic structure below.

Successful management of iliocostal impingement syndrome: A case series.

BACKGROUND: Iliocostal impingement syndrome is a rare, painful, and disabling condition associated with thoracic hyperkyphosis and kyphoscoliosis. There is little published literature regarding management of this syndrome. The purpose of this case series is to report treatment outcomes for iliocostal impingement syndrome with improving posture and back muscle strength. CASE DESCRIPTION AND METHODS: Thirty-eight women with thoracic hyperkyphosis or kyphoscoliosis and back and/or flank pain were diagnosed with iliocostal impingement syndrome on the basis of symptoms and spine radiographs. They were instructed in weighted kypho-orthosis use and taught a home back-extensor strengthening program. Outcome measures included posture evaluation and pain level. FINDINGS AND OUTCOMES: All patients reported immediate pain reduction with weighted kypho-orthosis trial. Nineteen patients returned within 2 years, and all had continued pain relief and posture improvement. CONCLUSIONS: Our findings suggest that successful management of iliocostal impingement syndrome is possible with a weighted kypho-orthosis and back strengthening program focusing on posture improvement. CLINICAL RELEVANCE: Iliocostal syndrome is a rare, painful, and disabling condition that severely affects quality of life. This report discusses our diagnostic and treatment approach to this syndrome, which has proven successful in our patient population.

Obesity and knee osteoarthritis are not associated with impaired quadriceps specific strength in adults.

OBJECTIVE: To assess whether adults, aged 50-59 years, who are obese or moderately to severely obese have impaired quadriceps strength and muscle quality in comparison with adults who are not obese, both groups with and without knee osteoarthritis (OA). DESIGN: Cross-sectional observational study. SETTING: Rural community acquired sample. SUBJECTS: Seventy-seven men and 84 women, aged 50-59 years. METHODS: Comparisons by using mixed models for clustered data (2 lower limbs per participant) between groups defined by body mass index (BMI) (<30 kg/m(2), 30-35 kg/m(2), and ≥35 kg/m(2)), with and without knee OA MAIN OUTCOME MEASUREMENT: The slope of the relationship between quadriceps muscle cross-sectional area (CSA) and isokinetic knee extensor strength (dynamometer) in each BMI and OA group. RESULTS: There were 113 limbs (48.7% women), 101 limbs (38.6% women), and 89 limbs (73.0% women) in the <30 kg/m(2), 30-35 kg/m(2), and ≥35 kg/m(2) BMI groups, respectively; knee OA was present in 10.6%, 28.7%, and 58.4% of the limbs in each of these respective groups. Quadriceps CSA did not significantly differ among BMI groups in either gender or between subjects with and without knee OA. Peak quadriceps strength also did not significantly differ by BMI group or by the presence of knee OA. Multivariable analyses also demonstrated that peak quadriceps strength did not differ by BMI group, even after adjusting for (a) gender, (b) OA status, (c) intramuscular fat, or (d) quadriceps attenuation. The slopes for the relationships between quadriceps strength and CSA did not differ by BMI group, OA status, or their interaction. CONCLUSIONS: Individuals who were obese and at risk for knee OA did not appear to have altered muscle strength or muscle quality compared with adults who were not obese and were aged 50-59 years. The absence of a difference in the relationship between peak quadriceps strength and CSA provided further evidence that there was not an impairment in quadriceps muscle quality in this cohort, which suggests that factors other than strength might mediate the association between obesity and knee OA.

Association of dynamic joint power with functional limitations in older adults with symptomatic knee osteoarthritis.

OBJECTIVES: To determine which lower-limb joint moments and powers characterize the level of gait performance of older adults with symptomatic knee osteoarthritis (OA). DESIGN: Cross-sectional observational study. SETTING: University motion analysis laboratory. PARTICIPANTS: Community-dwelling adults (N=60; 27 men, 33 women; age 50-79y) with symptomatic knee OA. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Physical function was measured using the long-distance corridor walk, the Short Physical Performance Battery, and the Late Life Function and Disability Instrument (LLFDI Function). Joint moments and power were estimated using an inverse dynamics solution after 3-dimensional computerized motion analysis. RESULTS: Subjects aged 64.2+/-7.4 years were recruited. Ranges (mean +/- SD) for the 400-m walk time and the LLFDI Advanced Lower-Limb Function score were 215.3 to 536.8 (304.1+/-62.3) seconds and 31.5 to 100 (57.0+/-14.9) points, respectively. In women, hip abductor moment (loading response), hip abductor power (midstance), eccentric hamstring moment (terminal stance), and power (terminal swing) accounted for 41%, 31%, 14%, and 48% of the variance in the 400-m walk time, respectively (model R(2)=.61, P<.003). In men, plantar flexor and hip flexor power (preswing) accounted for 19% and 24% of the variance in the 400-m walk time, respectively (model R(2)=.32, P=.025). CONCLUSIONS: There is evidence that men and women with higher mobility function tend to rely more on an ankle strategy rather than a hip strategy for gait. In higher functioning men, higher knee extensor and flexor strength may contribute to an ankle strategy, whereas hip abductor weakness may bias women with lower mobility function to minimize loading across the knee via use of a hip strategy. These parameters may serve as foci for rehabilitation interventions aimed at reducing mobility limitations.