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The use of low-energy deep-red (DR) and near-infrared (NIR) light to excite chromophores enables catalysis to ensue across barriers such as materials and tissues. Herein, we report the detailed photophysical characterization of a library of OsII polypyridyl photosensitizers that absorb low-energy light. By tuning ligand scaffold and electron density, we access a range of synthetically useful excited state energies and redox potentials.1 Introduction1.1 Scope1.2 Measuring Ground-State Redox Potentials1.3 Measuring Photophysical Properties1.4 Synthesis of Osmium Complexes2 Properties of Osmium Complexes2.1 Redox Potentials of Os(L)2-Type Complexes2.2 Redox Potentials of Os(L)3-Type Complexes2.3 UV/Vis Absorption and Emission Spectroscopy3 Conclusions

The complex connectivity of the mammalian brain underlies its function, but understanding how interconnected brain regions interact in neural processing remains a formidable challenge. Here we address this problem by introducing a genetic probe that permits selective functional imaging of distributed neural populations defined by viral labeling techniques. The probe is an engineered enzyme that transduces cytosolic calcium dynamics of probe-expressing cells into localized hemodynamic responses that can be specifically visualized by functional magnetic resonance imaging. Using a viral vector that undergoes retrograde transport, we apply the probe to characterize a brain-wide network of presynaptic inputs to the striatum activated in a deep brain stimulation paradigm in rats. The results reveal engagement of surprisingly diverse projection sources and inform an integrated model of striatal function relevant to reward behavior and therapeutic neurostimulation approaches. Our work thus establishes a strategy for mechanistic analysis of multiregional neural systems in the mammalian brain.

Photocatalysis driven by visible and ultraviolet irradiation is a fundamental tool for synthetic chemists. Recently, expansion of this tool to near-infrared (NIR) light has gained in popularity. Herein, we report the detailed photophysical characterization of a library of OsII polypyridyl photosensitizers that absorb NIR irradiation. By tuning ligand scaffold and electron density, we access a range of synthetically useful excited state energies and redox potentials.

Anatomic total shoulder arthroplasty (aTSA) and reverse shoulder arthroplasty (RSA) are increasingly common, with volume projected to increase over 90% by the year 2025. Therefore, it is critical to understand the expected longevity of aTSA using modern implants and techniques, rates of conversion to RSA, and most common indications for conversion if surgeons are to properly diagnose and treat patients. A retrospective review was conducted of 800 patients who had undergone aTSA, RSA, or hemiarthroplasty (HA) between 2015 and 2019 at a tertiary-care academic medical center. All patients who had undergone primary aTSA were included. Patients who had undergone primary HA, primary RSA, or had had primary surgery at an outside hospital were excluded. Primary outcomes were indications for and time to conversion from aTSA to RSA. Secondary outcomes were indications for primary aTSA and preliminary survivorship data of modern implants. Between 2015 and 2019, 235 patients underwent primary aTSA, with a mean time to follow-up of 3.43 years (0.07-5.24 years). Mean time to conversion from aTSA to RSA was 15.6 months, with a 2.13% conversion rate (5 patients). Eighty percent of the conversions (4 patients) were due to rotator cuff tear. We found that 2.13% of primary aTSA patients at our institution were converted to RSA at a mean of 15.6 months after the primary procedure. Rotator cuff tears were the indication for 80% of these. Since conversions occurred relatively soon after primary surgery, the authors recommend use of MRI without contrast prior to surgery to possibly reduce the risk of such failures. This study was a Level 3 retrospective database review.

The complex connectivity of the mammalian brain underlies its function, but understanding how interconnected brain regions interact in neural processing remains a formidable challenge. Here we address this problem by introducing a genetic probe that permits selective functional imaging of neural circuit elements defined by their synaptic interrelationships throughout the brain. The probe is an engineered enzyme that transduces cytosolic calcium dynamics of probe-expressing cells into localized hemodynamic responses that can be selectively visualized by functional magnetic resonance imaging. Using a viral vector that undergoes retrograde transport, we apply the probe to characterize a brain-wide network of monosynaptic inputs to the striatum activated in a deep brain stimulation paradigm in rats. The results reveal engagement of surprisingly diverse projection sources and inform an integrated model of striatal function relevant to reward behavior and therapeutic neurostimulation approaches. Our work thus establishes a potent strategy for mechanistic analysis of distributed neural systems.

Studying the function and dysfunction of complex biological systems necessitates comprehensive understanding of individual cells. Advancements in three-dimensional (3D) tissue processing and imaging modalities have enabled rapid visualization and phenotyping of cells in their spatial context. However, system-wide interrogation of individual cells within large intact tissue remains challenging, low throughput, and error-prone owing to the lack of robust labeling technologies. Here we introduce a rapid, versatile, and scalable method, eFLASH, that enables complete and uniform labeling of organ-scale tissue within one day. eFLASH dynamically modulates chemical transport and reaction kinetics to establish system-wide uniform labeling conditions throughout the day-long labeling period. This unique approach enables the same protocol to be compatible with a wide range of tissue types and probes, enabling combinatorial molecular phenotyping across different organs and species. We applied eFLASH to generate quantitative maps of various cell types in mouse brains. We also demonstrated multidimensional cell profiling in a marmoset brain block. We envision that eFLASH will spur holistic phenotyping of emerging animal models and disease models to help assess their functions and dysfunctions.

Here we describe an image processing pipeline for quantitative analysis of terabyte-scale volumetric images of SHIELD-processed mouse brains imaged with light-sheet microscopy. The pipeline utilizes open-source packages for destriping, stitching, and atlas alignment that are optimized for parallel processing. The destriping step removes stripe artifacts, corrects uneven illumination, and offers over 100x speed improvements compared to previously reported algorithms. The stitching module builds upon Terastitcher to create a single volumetric image quickly from individual image stacks with parallel processing enabled by default. The atlas alignment module provides an interactive web-based interface that automatically calculates an initial alignment to a reference image which can be manually refined. The atlas alignment module also provides summary statistics of fluorescence for each brain region as well as region segmentations for visualization. The expected runtime of our pipeline on a whole mouse brain hemisphere is 1-2 d depending on the available computational resources and the dataset size.