The role of internal architecture in producing high-strength 3D printed cobalt-chromium objects.

PURPOSE: The objectives of the current study were to estimate the influence of self-reinforced hollow structures with a graded density on the dimensional accuracy, weight, and mechanical properties of Co-Cr objects printed with the direct metal laser sintering (DMLS) technique. MATERIALS AND METHODS: Sixty-five dog-bone samples were manufactured to evaluate the dimensional accuracy of printing, weight, and tensile properties of DMLS printed Co-Cr. They were divided into Group 1 (control) (n = 5), Group 2, 3, and 4 with incorporated hollow structures based on (spherical, elliptical, and diamond) shapes; they were subdivided into subgroups (n = 5) according to the volumetric reduction (10%, 15%, 20% and 25%). Radiographic imaging and microscopic analysis of the fractographs were conducted to validate the created geometries; the dimensional accuracy, weight, yield tensile strength, and modulus of elasticity were calculated. The data were estimated by one-way ANOVA and Duncan's tests at P < .05. RESULTS: The accuracy test showed an insignificant difference in the x, y, z directions in all printed groups. The weight was significantly reduced proportionally to the reduced volume fraction. The yield strength and elastic modulus of the control group and Group 2 at 10% volume reduction were comparable and significantly higher than the other subgroups. CONCLUSION: The printing accuracy was not affected by the presence or type of the hollow geometry. The weight of Group 2 at 10% reduction was significantly lower than that of the control group. The yield strength and elastic modulus of the Group 2 at a 10% reduction showed means equivalent to the compact objects and were significantly higher than other subgroups.

The influence of internally architected voids in the creation of high-strength, low-weight 3D-printed cobalt-chromium prototypes.

Background: The additive manufacturing technology made the topology optimization technique feasible. This technique can indefinitely reduce the weight of the printed items with a promising increase in the mechanical properties of that item. Materials and Methods: In the current experimental study, 50 samples were fabricated for a 3-point bending test. They were divided into (n = 5) as a control Group 1 free of internal geometries, (n = 15) for each of Groups 2-4, and they were subdivided into (n = 5) for each percentage of reduction per volume (10%, 15%, and 20%). Spherical, ovoid, and diamond shapes were each group's fundamental geometries, respectively. Cylindrical tunnels connected the voids in each group. Radiographic images were performed to validate the created geometries, the weight was measured, and flexural strength and modulus of elasticity were calculated. Data were analyzed by one-way ANOVA and Duncan's post hoc tests at P < 0.05. Results: The weight results showed a significant reduction in mass. The flexural strength of Group 2 at a 10% reduction per volume had the highest mean significantly without compromising the elastic modulus. In comparison, the means of group 4 at 20% reduction showed the lowest level of toughness. Conclusion: The weight was reduced according to the reduction percentage. The flexural strength of Group 2 at a 10% reduction showed the highest degree of toughness among all groups. The void shape and density influenced the mechanical properties tested.

Diversity trends in traumatic brain injury clinical trials in the United States.

BACKGROUND: This study aims to understand the demographic representation of patients in Traumatic Brain Injury (TBI) clinical trials by evaluating the proportions of patients from various demographic categories amongst completed TBI clinical trials in the United States. METHODS: ClinicalTrials.gov was queried for active TBI clinical trials. One hundred and eight completed trials in the United States were selected based on inclusion criteria, and information regarding intervention, setting, age, sex, race, and ethnicity was extracted. 2002-2006 TBI incidence data was obtained from the CDC. Chi-squared testing was applied to analyze the relationship between distributions of race and sex in the collected clinical trials and the national TBI data, and logistic regression was conducted to identify variables that may predict reporting of race or ethnicity. RESULTS: About 53.7% of selected clinical trials reported racial data and 34.3% reported ethnicity data. Logistic regression identified that clinical trials in defined phases were more likely to report racial data (p = 0.047 [1.015, 9.603]). CONCLUSION: Current TBI trials do not consistently report race or ethnicity data. Future efforts to ensure equitable representation in clinical trials may involve reform of recruitment processes and accountability measures implemented within the grant application process to ensure proper racial and ethnicity data reporting.

Shifts in Reduction Mammaplasty Surgical Volumes With the Emergence of a Global Pandemic.

INTRODUCTION: The onset of the COVID-19 pandemic resulted in significant changes to the surgical caseload for various surgery departments across the United States. As medical institutions prioritized resources for the expected increase in patient volumes due to the SARS-CoV-2 viral infection, surgical departments saw a decrease in nonemergent and elective surgical procedures. Reduction mammoplasties, which are largely covered by insurance, are among the elective procedures that provide significant revenue to the hospital. This expected decline in procedures suggests a potential decline in revenue provided by the plastic surgery department of a hospital. The purpose of this study was to analyze the loss of revenue experienced by a single academic medical institution due to changes in breast reduction mammoplasty volumes during the COVID-19 pandemic. METHODS: Upon institutional review board approval, using the Augusta University Medical Center's Financial Billing Data, 373 patients who underwent bilateral reduction mammoplasty were queried. A time horizon of March 2019 to February 2022 was used to determine the pre- and post-COVID case load and charges that were incurred. Statistical analysis to compare the prior 12 months and after 24 months of COVID was conducted using 2 samples of equal variance t test and F test confirming equal variance. RESULTS: There was a statistically significant increase in the number of reduction mammoplasties performed per month from the year before the onset of COVID-19 (March 2020) to the 2 years after (6.6-11.4 per month, P = 0.0024). There was a statistically significant increase in the per-month charges from the AU Health system for reduction mammoplasties for the same period ($31,780.92-$52,113.34 per month, P = 0.0054). Although there was an increase in per-month revenue from reduction mammoplasties, this increase failed to reach statistical significance ($7,059.95-$10,423.51 per month, P = 0.064). CONCLUSIONS: The plastic surgery department saw a statistically significant increase in reduction mammoplasty cases and subsequent charges in the post-COVID cohort. These findings suggest that the emergence of a nationwide pandemic did not necessarily lead to a decrease in the volume of nonemergent surgical cases despite an expected decrease in caseload due to the need to reallocate hospital resources. On the contrary, there was an increase in caseload suggesting that there may be other factors contributing to patients' pursuance of reduction mammoplasty post-COVID including convenience, resulting from time off due to pandemic, meeting insurance-covered reduction criteria, and projected recovery time.

Salivary gland adenoid cystic carcinoma in the U.S population: Importance of grade, site of metastases, and adjuvant radiation for survival.

BACKGROUND: Adenoid cystic carcinoma (AdCC) is a rare and relatively heterogenous salivary gland malignancy, for which there is debate regarding grading, and clinical prognostic factors, including the role of adjuvant radiotherapy. METHODS: Surveillance, Epidemiology, and End Results (SEER) data were reviewed for AdCC cases from 2000 to 2018. RESULTS: A total of 1978 patients with AdCC were identified. Most patients were between 50 and 59 years of age (21.4 %), female (59.9 %), and Caucasian (76.8 %). Most tumors were localized at presentation (44.3 %), and moderately differentiated (or grade II) (43.7 %). Overall and DSS 5-year survival rates were 70.7 % (95 % CI, 69.9-78.8), and 78.6 % (95 % CI, 77.6-79.6). The best overall 5-year survival rate was observed for those treated with surgery plus radiation, 76.8 % (95 % CI, 75.5-78.1). Multivariate analysis revealed male sex, age > 65 (H.R. 2.659 (95 % CI,2.291-3.098), p < .001), grade III/IV (H.R.5.172 (95 % CI, 3.418-7.824), p < .001), nodal metastasis, distant metastasis (H.R. 2.400 (95 % CI, 2.178-2.645), p < .001), chemotherapy only, and combination therapy as negative prognostic factors, and receiving surgery plus radiation therapy (H.R.0.586 (95 % CI, 0.505-0.679), p < .001) as a positive prognostic factor. When limited just to the lungs, had much better survival than those patients with distant metastases to other sites such as the bones and liver (p < .001). CONCLUSION: This SEER study identifies grade, particularly III and IV, to be the strongest single predictor of worse survival. Patients did best when treated with surgery and postoperative radiotherapy. These results can inform future management of patients with this challenging cancer type.

Use of Advanced Diagnostics for Timely Identification of Travel-associated Leptospira santarosai Infection in Four Adolescents Through Plasma Microbial Cell-free DNA Sequencing With the Karius Test.

BACKGROUND: Leptospirosis is an important zoonotic infection worldwide. Diagnosis of leptospirosis is challenging given its nonspecific clinical symptoms that overlap with other acute febrile illnesses and limitations with conventional diagnostic testing. Alternative advanced diagnostics, such as microbial cell-free DNA (mcfDNA), are increasingly being used to aid in the diagnosis of infections and can be applied to pathogens with public health importance such as Leptospira , a nationally notifiable disease. METHODS: The Karius Test uses plasma mcfDNA sequencing to detect and quantify DNA-based pathogens. This test offered through the Karius lab detected 4 cases of Leptospira santarosai during a 5-month period across the United States in 2021 and were clinically reviewed. RESULTS: In our case series, 4 adolescents with recent travel to Central America (Costa Rica, n = 3 and Belize, n = 1) from April to August 2021 were diagnosed with leptospirosis. While a large workup was performed in all cases, mcfDNA testing was the first test to detect L. santarosai as the microbiological diagnosis in all cases. CONCLUSIONS: Results of the Karius Test enabled rapid, noninvasive diagnosis of leptospirosis allowing for targeted therapy. Use of mcfDNA can be utilized for diagnosis of pathogens where conventional testing is challenging or limited. This in turn can enable quick diagnosis for targeted treatment and potentially aid in supporting case definitions of reportable diseases of public health concern.

Who enrolls and why? Examining center-specific underlying patterns behind enrollment: a New York City-based traumatic brain injury model systems study.

BACKGROUND: To elucidate the sociodemographic and study factors involved in enrollment in the Traumatic Brain Injury Model System (TBIMS) database, this study examined the effect of a variety of variables on enrollment at a local TBIMS center. METHODS: A sample of 654 individuals from the local TBIMS center was studied examining enrollment by age, gender, race, ethnicity, homelessness status at date of injury, history of homelessness, health insurance status, presence of social support, primary language, consenting in hospital or after discharge, and the need for an interpreter. Binary logistic regression was conducted to identify variables that predict center-based enrollment into TBIMS. RESULTS: Results demonstrated that older age was associated with decreasing enrollment (OR = 0.99, p = 0.01), needing an interpreter made enrollment less likely (OR = 0.33, p < 0.01), being primarily Spanish speaking predicted enrollment (OR = 3.20, p = 0.02), Hispanic ethnicity predicted enrollment (OR = 7.31, p = 0.03), and approaching individuals in the hospital predicted enrollment (OR = 6.94, p < 0.01). Here, OR denotes the odds ratio estimate from a logistic regression model and P denotes the corresponding p-value. CONCLUSIONS: These results can be useful in driving enrollment strategies at this center for other similar TBI research, and to contribute a representative TBI sample to the national database.

The role of internal architecture in producing high-strength 3D printed cobalt-chromium objects

PURPOSE@#The objectives of the current study were to estimate the influence of self-reinforced hollow structures with a graded density on the dimensional accuracy, weight, and mechanical properties of Co-Cr objects printed with the direct metal laser sintering (DMLS) technique. @*MATERIALS AND METHODS@#Sixty-five dog-bone samples were manufactured to evaluate the dimensional accuracy of printing, weight, and tensile properties of DMLS printed Co-Cr. They were divided into Group 1 (control) (n = 5), Group 2, 3, and 4 with incorporated hollow structures based on (spherical, elliptical, and diamond) shapes; they were subdivided into subgroups (n = 5) according to the volumetric reduction (10%, 15%, 20% and 25%). Radiographic imaging and microscopic analysis of the fractographs were conducted to validate the created geometries; the dimensional accuracy, weight, yield tensile strength, and modulus of elasticity were calculated. The data were estimated by one-way ANOVA and Duncan’s tests at P < .05. @*RESULTS@#The accuracy test showed an insignificant difference in the x, y, z directions in all printed groups. The weight was significantly reduced proportionally to the reduced volume fraction. The yield strength and elastic modulus of the control group and Group 2 at 10% volume reduction were comparable and significantly higher than the other subgroups. @*CONCLUSION@#The printing accuracy was not affected by the presence or type of the hollow geometry. The weight of Group 2 at 10% reduction was significantly lower than that of the control group. The yield strength and elastic modulus of the Group 2 at a 10% reduction showed means equivalent to the compact objects and were significantly higher than other subgroups.

Tensile and transverse strength of novel copolymers for denture base

Objectives: Compare tensile and transverse strength of new copolymers for denture base. Materials and methods: The specimens were prepared from heat cured acrylic resin with three types of additives: Acryester B, Ethoxycarbonylethylene, and Propenoic acid at a percentage of 5% and 10%. The tensile and transverse strains were tested, recorded and compared. Results: The analysis of variance display statistically significant difference. The p-value was 0.001 for each of tensile and transverse strain tests. Conclusions: The tensile strength of the novel copolymers increased. The transverse strength of some of the novel copolymers increased.