Continuous theta burst TMS of area MT+ impairs attentive motion tracking.

Attentive motion tracking deficits measured using multiple object tracking (MOT) tasks have been identified in a number of neurodevelopmental disorders such as amblyopia and autism. These deficits are often attributed to the abnormal development of high-level attentional networks. However, neuroimaging evidence from amblyopia suggests that reduced MOT performance can be explained by impaired function in motion-sensitive area MT+ alone. To test the hypothesis that a subtle disruption of MT+ function could cause MOT impairment, we assessed whether continuous theta burst stimulation (cTBS) of MT+ influenced MOT task accuracy in individuals with normal vision. The MOT stimulus consisted of four target and four distractor dots and was presented at ±10° eccentricity (right/left hemifield). fMRI-guided cTBS was applied to left MT+. Participants (n = 13, age: 27 ± 3) attended separate active and sham cTBS sessions where the MOT task was completed before, 5-min post- and 30-min post-cTBS. Active cTBS significantly impaired MOT task accuracy relative to baseline for the right (stimulated) hemifield 5-min (10 ± 2% reduction) and 30-min (14 ± 3% reduction) post-stimulation. No impairment occurred within the left (control) hemifield after active cTBS or for either hemifield after sham cTBS. These results highlight the importance of lower level motion processing for MOT, suggesting that a minor disruption of MT+ function alone is sufficient to cause a deficit in MOT performance.

The Diabetic Foot-Pain-Depression Cycle.

BACKGROUND: More than 86,000 Americans with type 2 diabetes mellitus (T2DM) undergo nontraumatic lower-extremity amputations annually. The opioid-prescribing practice of podiatric surgeons remains understudied. We hypothesized that patients with T2DM who undergo any forefoot amputation while using antidepressant medication will have reduced odds of using opioids beyond 7 days. METHODS: We completed a retrospective cohort study examining patients with T2DM who underwent forefoot amputation (toe, ray, transmetatarsal). Data were restricted to patients with a hemoglobin A1c level less than 8.0% and an ankle-brachial index greater than 0.8. The outcome was use of postoperative opioids beyond 7 days. Patients received an initial opioid prescription of 7 days or less. We developed simple logistic regression models to identify the odds of a patient using opioids beyond 7 days by patient variables: age, race, sex, amputation level, body mass index, antidepressant medication use, and marital status. Variables with P < .1 in the univariate analysis were included in the multiple logistic regression model. RESULTS: Fifty patients met the inclusion criteria. Antidepressant use and marital status were the only statistically significant variables. Adjusting for marital status, patients with antidepressant use had decreased odds (odds ratio, 0.018; 95% confidence interval, 0.001-0.229; P = .002) of using opioids beyond 7 days after a diabetic forefoot amputation. CONCLUSIONS: Patients with T2DM who used antidepressants had significantly reduced odds of using opioids beyond 1 week after forefoot amputations compared with those without antidepressant use. We proposed an underlying diabetic foot-pain-depression cycle. To break the cycle, podiatric surgeons should screen this population for depression preoperatively and postoperatively and not hesitate to make a mental health referral if warranted. Nontraumatic amputations can be a traumatic experience for patients; psychiatrists and other mental health providers should be members of limb preservation teams.

Bidirectional triplet exciton transfer between silicon nanocrystals and perylene.

Hybrid materials comprised of inorganic quantum dots functionalized with small-molecule organic chromophores have emerged as promising materials for reshaping light's energy content. Quantum dots in these structures can serve as light harvesting antennas that absorb photons and pass their energy to molecules bound to their surface in the form of spin-triplet excitons. Energy passed in this manner can fuel upconversion schemes that use triplet fusion to convert infrared light into visible emission. Likewise, triplet excitons passed in the opposite direction, from molecules to quantum dots, can enable solar cells that use singlet fission to circumvent the Shockley-Queisser limit. Silicon QDs represent a key target for these hybrid materials due to silicon's biocompatibility and preeminence within the solar energy market. However, while triplet transfer from silicon QDs to molecules has been observed, no reports to date have shown evidence of energy moving in the reverse direction. Here, we address this gap by creating silicon QDs functionalized with perylene chromophores that exhibit bidirectional triplet exciton transfer. Using transient absorption, we find triplet transfer from silicon to perylene takes place over 4.2 µs while energy transfer in the reverse direction occurs two orders of magnitude faster, on a 22 ns timescale. To demonstrate this system's utility, we use it to create a photon upconversion system that generates blue emission at 475 nm using photons with wavelengths as long as 730 nm. Our work shows formation of covalent linkages between silicon and organic molecules can provide sufficient electronic coupling to allow efficient bidirectional triplet exchange, enabling new technologies for photon conversion.