Enhanced anchorage of tissue-engineered cartilage using an osteoinductive approach

Articular cartilage injuries occur frequently in the knee joint. Several methods have been implemented clinically, to treat osteochondral defects but none have been able to produce a long term, durable solution. Photopolymerizable cartilage tissue engineering approaches appear promising; however, fundamentally, forming a stable interface between the tissue engineered cartilage and native tissue, mainly subchondral bone and native cartilage, remains a major challenge. The overall objective of this research is to find a solution for the current problem of dislodgment of tissue engineered cartilage at the defect site for the treatment of degraded cartilage that has been caused due to knee injuries or because of mild to moderate level of osteoarthritis. For this, an in-vitro model was created to analyze the integration of tissue engineered cartilage with the bone, healthy and diseased cartilage over time. We investigated the utility of hydroxyapatite (HA) nanoparticles to promote controlled bone-growth across the bone-cartilage interface in an in vitro engineered tissue model system using bone marrow derived stem cells. We also investigated the application of HA nanoparticles to promote enhance integration between tissue engineered cartilage and native cartilage both in healthy and diseased states. Samples incorporated with HA demonstrated significantly higher interfacial shear strength (at the junction between engineered cartilage and engineered bone and also with diseased cartilage) compared to the constructs without HA (p < 0.05), after 28 days of culture. These findings indicate that the incorporation of HA nanoparticles permits more stable anchorage of the injectable hydrogel-based engineered cartilage construct via augmented integration between bone and cartilage.^

Perceptions of French and Creole Among First-Generation Adult Haitian English Language Learners

Context: Due to a unique combination of factors, outdoor athletes in the Southeastern United States are at high risk of lightning deaths and injuries. Lightning detection methods are available to minimize lightning strike victims. Objective: Becoming aware of the risk factors that predispose athletes to lightning strikes and determining the most reliable detection method against hazardous weather will enable Certified Athletic Trainers to develop protocols that protect athletes from injury. Data Sources: A comprehensive literature review of Medline and Pubmed using key words: lightning, lightning risk factors, lightning safety, lightning detection, and athletic trainers and lightning was completed. Data Synthesis: Factors predisposing athletes to lighting death or injury include: time of year, time of day, the athlete’s age, geographical location, physical location, sex, perspiration level, and lack of education and preparedness by athletes and staff. Although handheld lightning detectors have become widely accessible to detect lightning strikes, their performance has not been independently or objectively confirmed. There is evidence that these detectors inaccurately detect strike locations by recording false strikes and not recording actual strikes. Conclusions: Lightning education and preparation are two factors that can be controlled. Measures need to be taken by Certified Athletic Trainers to ensure the safety of athletes during outdoor athletics. It is critical for athletic trainers and supervising staff members to become fully aware of the risks of lightning strikes in order to most effectively protect everyone under their supervision. Even though lightning detectors have been manufactured in an attempt to minimize death and injuries due to lightning strikes, none of the detectors have been proven to be 100% effective. Educating coaches, athletes, and parents on the risks of lightning and the detection methods available, while implementing an emergency action plan for lightning safety, is crucial to ensure the well being of the student-athlete population.

U.S. Army front line artillery observation during the 1945 Okinawa campaign: An oral history case study

This dissertation explores the role of artillery forward observation teams during the battle of Okinawa (April–June 1945). It addresses a variety of questions associated with this front line artillery support. First, it examines the role of artillery itself in the American victory over the Japanese on Okinawa. Second, it traces the history of the forward observer in the three decades before the end of World War II. Third, it defines the specific role of the forward observation teams during the battle: what they did and how they did it during this three-month duel. Fourth, it deals with the particular problems of the forward observer. These included coordination with the local infantry commander, adjusting to the periodic rotation between the front lines and the artillery battery behind the line of battle, responding to occasional problems with "friendly fire" (American artillery falling on American ground forces), dealing with personnel turnover in the teams (due to death, wounds, and illness), and finally, developing a more informal relationship between officers and enlisted men to accommodate the reality of this recently created combat assignment. Fifth, it explores the experiences of a select group of men who served on (or in proximity to) forward observation teams on Okinawa. Previous scholars and popular historians of the battle have emphasized the role of Marines, infantrymen, and flame-throwing armor. This work offers a different perspective on the battle and it uses new sources as well. A pre-existing archive of interviews with Okinawan campaign forward observer team members conducted in the 1990s forms the core of the oral history component of this research project. The verbal accounts were checked against and supplemented by a review of unit reports obtained from the U.S. National Archives and various secondary sources. The dissertation concludes that an understanding of American artillery observation is critical to a more complete comprehension of the battle of Okinawa. These mid-ranking (and largely middle class) soldiers proved capable of adjusting to the demands of combat conditions. They provide a unique and understudied perspective of the entire battle.