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Background While studies have demonstrated favorable outcomes in utilization of primary total shoulder arthroplasty (TSA) for the treatment of glenohumeral osteoarthritis (OA), adverse events such as infections can still occur. Periprosthetic joint infections (PJIs) are associated with worse outcomes and patient morbidity. The purpose of this study was to: (1) compare patient demographics amongst TSA patients with and without PJIs following primary TSA; and (2) identify patient-related risk factors for PJIs following primary TSA. Methods Patients undergoing primary TSA for the treatment of glenohumeral OA were identified using the Mariner administrative claims database by CPT code 23,472. Laterality modifiers were utilized to ensure PJIs were developing in the correct laterality as those patients undergoing primary TSA. Inclusion for the study group consisted of patients who developed PJIs within 2-years after the index procedure, whereas patients who did not develop PJIs served as the comparison cohort. Primary outcomes analyzed included patient demographics and patient-related risk factors for PJIs following primary TSA. A stepwise backwards elimination multivariate binomial logistic regression analyses was performed to determine the odds (OR) of PJIs in patients undergoing primary TSA. A P value less than .05 was considered statistically significant. Results The query yielded 15,396 patients who underwent primary TSA for glenohumeral OA, of which 191 patients developed PJIs and 15,205 did not develop PJIs. The study found statistically significant differences amongst patients who did and did not develop PJIs following primary TSA with respect to age, sex, and presence of comorbid conditions. Risk factors associated with developing PJIs following primary TSA included: pathologic weight loss (OR: 2.06, P Conclusion As the number of primary TSAs for the treatment of glenohumeral OA increase worldwide, identifying modifiable risk-factors to reduce the incidence of infection is critical. The study found various modifiable and non-modifiable risk factors associated with developing PJIs following primary TSA. This study is valuable to orthopedists in order to identify and risk-stratify patients with regard to PJI in the setting of primary TSA for OA. Level of Evidence Level III; Case-Control Study

Introduction There is a substantial need for orthopaedic surgery-specific boot camps due to the limited orthopaedic and musculoskeletal education in medical school, which inadequately prepares medical students for their orthopaedic surgery sub-internships. The aim of this study is to identify the impact of the novel orthopaedic surgery boot camp on medical students' confidence with key orthopaedic topics. Methods A cross-sectional study was conducted using an anonymous online survey distributed to medical students attending the novel orthopaedic surgery boot camp. The boot camp consisted of a four-day immersion course into the basics of orthopaedic surgery principles through both didactic and skills-based educational series. The medical students' confidence in orthopaedic surgery clinical and technical skills were assessed by comparing the students' survey responses before and after attending each of the sessions. Results Twelve fourth-year medical students and 15 second-year medical students attended the boot camp. All the sessions attended by the medical students were statistically significant in improving their confidence in the subject matter and skills-based training. Hundred percent (100%) of the fourth-year medical students recommend future orthopaedic surgery-bound medical students to attend this boot camp. Conclusion A dedicated orthopaedic surgery boot camp focused on clinical and technical skills plays a key role in increasing medical students' confidence with key orthopaedic topics by providing an opportunity to practice these skills in a supervised environment with real-time feedback. This novel boot camp can provide a framework for creating a longitudinal course for medical students to augment the musculoskeletal education taught in medical school education.

BACKGROUND Trauma patients are high-risk for venous thromboembolism (VTE). Lower extremity screening duplex ultrasonography (LESDUS) is controversial and not standardized for early VTE diagnosis. By implementing risk stratification and selective screening, we aim to optimize resource utilization. MATERIALS AND METHODS A retrospective review were conducted at a Level-1 Trauma Center, January 2015-October 2019. LESDUS was performed within 72-h of presentation, then weekly. Demographics, VTE data, and outcomes were collected from the trauma registry. Risk assessment profile (RAP) score was calculated based on collected data. RESULTS Of 5,645 patients included, 2,813 (49.8%) were screened for lower extremity deep vein thrombosis (LEDVT). Of 187 patients with LEDVT, 154 were diagnosed on LESDUS, 18 after negative LESDUS, and 15 in unscreened patients. Patients with VTE were older (61y versus 55, P < 0.01), more often male (70.9% versus 29.1%, P = 0.03), had higher ISS (16 versus 10, P < 0.01), longer hospital length of stay (LOS) (11.5 d versus 3, P < 0.01), longer ICU LOS (4.5 d versus 1, P < 0.01), and increased mortality (9.1% versus 4.3%, P = 0.01). RAP was higher in VTE patients versus those without (nine versus three, P < 0.01). RAP ≥8 was 62.5% sensitive and 70.4% specific for VTE. Chemoprophylaxis delay also correlated with increased VTE (OR = 1.48, 95% CI = 1.03-2.12). CONCLUSIONS VTE remains a significant complication in trauma patients. Despite a universal LESDUS protocol, only 50% of patients underwent screening and 20% of all LE DVTs were not identified on LESDUS. To optimize resource utilization and protocol adherence, LESDUS should only be performed if RAP ≥8 or if unable to administer timely chemoprophylaxis.

We have studied the mutual effects of chloride ion and EDTA on the dimer-tetramer assembly of human deoxyhemoglobin and oxyhemoglobin. It is found that these two anions have similar but interdependent effects. In low C1- (.01 M) increasing concentrations of EDTA are found to decrease both forward and reverse rate constants for deoxyhemoglobin, whereas no effect is observed at 0.1 M C1-. These results suggest that binding of anions at the alpha 1 beta 2 intersubunit contact may stabilize both the dimeric and tetrameric forms of the deoxy molecule, thus inhibiting both the dissociation and reassociation reactions. The overall effects of EDTA and low C1- on the dimer-tetramer equilibrium constants are found to be distinctly different in deoxy and oxyhemoglobins with a major effect on the oxy form. These findings establish validity of the results from previous thermodynamic studies carried out in approximately physiological C1- concentrations along with the small amounts of EDTA which are used to minimize artifacts of oxidation. As observed for deoxyhemoglobin, it is found that in 0.1 M C1- ion there is no further effect of EDTA on the oxyhemoglobin dimer-tetramer equilibrium.

In solution-state NMR spectroscopy, dynamic processes can be probed provided the nuclear relaxation rate constant does not exceed the rate constant of the process. Phenomena occurring on a time scale longer than the spin-lattice relaxation time constant, T1, were not amenable to study by conventional NMR. The discovery of long-lived nuclear spin states (LLS) in 2004, by M. Levitt, M. Carravetta and O. W. Johannessen, showed that lifetimes of magnetization can be much higher than T1. LLS experiments can be performed either in zero or in high magnetic fields for scalar-coupled proton spin pairs. This thesis contributes methods for exciting and preserving LLS in high field for a wide class of molecules, including sugars, amino acids and nucleotides. Slow diffusion has been measured for a mixture of molecules having different NMR parameters using LLS. Conformational exchange could also be followed by exchange spectroscopy in BPTI. Recently, LLS have been observed in highly mobile parts (Gly-75 and 76) of Ubiquitin. Dynamic Nuclear Polarization (DNP) is one of the methods to overcome the inherent low sensitivity of NMR spectroscopy. We have conceived an experiment to preserve DNP enhanced magnetization by conversion into LLS. A way of improving resolution and sensitivity of NMR has been designed by creation of long-lived coherences (LLC) in biomolecules.

Slow dynamic processes, such as biomolecular folding/unfolding, macromolecular diffusion, etc., can be conveniently monitored by solution-state two-dimensional (2D) NMR spectroscopy, provided the inverse of their rate constants does not exceed the nuclear spin-lattice relaxation time constants (T1). The discovery of long-lived states (LLS) by Malcolm Levitt's group opened a new dimension for the study of slow dynamic phenomena, as magnetization stored in the form of LLS decays with the time constants TLLS, where in many cases TLLS >> T1. In this thesis, various excitation methods and applications of LLS are discussed. Broadband excitation of LLS is suitable to monitor slow processes and has been applied to study the slow ring-flip in tyrosine residues of BPTI (Bovine Pancreatic Trypsin Inhibitor), as well as to perform simultaneous measurements of diffusion coefficients in mixtures of molecules with arbitrary J-couplings and chemical shifts. The applications of LLS, initially believed to be limited to isolated spin-½ pairs, were extended to larger spin systems, including some common amino acids like Serine, Aspartic Acid, etc. LLS have been observed in Glycine residues of small peptides like Ala-Gly, as well as in mobile parts of proteins, e.g., in Gly 75 and 76 of Ubiquitin. The lifetimes TLLS are more sensitive to dipolar interactions with external spins than longitudinal and transverse relaxation time constants, T1 or T2, and therefore can provide structural information for unfolded proteins. The unfolding of Ubiquitin by addition of Urea and by varying pH was followed using LLS. The excitation of coherent superpositions across singlet and triplet states, which we call long-lived coherences (LLC's), leads to resolution enhancement in conventional NMR spectroscopy. New methods have been designed to store hyperpolarized (13C or 1H) magnetization in the form of LLS and have been demonstrated using samples of Ala-Gly and Acrylic Acid.