Magnetic resonance imaging of anterior cruciate ligament rupture

BACKGROUND: Magnetic resonance (MR) imaging is a useful diagnostic tool for the assessment of knee joint injury. Anterior cruciate ligament repair is a commonly performed orthopaedic procedure. This paper examines the concordance between MR imaging and arthroscopic findings. METHODS: Between February, 1996 and February, 1998, 48 patients who underwent magnetic resonance (MR) imaging of the knee were reported to have complete tears of the anterior cruciate ligament (ACL). Of the 48 patients, 36 were male, and 12 female. The average age was 27 years (range: 15 to 45). Operative reconstruction using a patellar bone-tendon-bone autograft was arranged for each patient, and an arthroscopic examination was performed to confirm the diagnosis immediately prior to reconstructive surgery. RESULTS: In 16 of the 48 patients, reconstructive surgery was cancelled when incomplete lesions were noted during arthroscopy, making reconstructive surgery unnecessary. The remaining 32 patients were found to have complete tears of the ACL, and therefore underwent reconstructive surgery. Using arthroscopy as an independent, reliable reference standard for ACL tear diagnosis, the reliability of MR imaging was evaluated. The true positive rate for complete ACL tear diagnosis with MR imaging was 67%, making the possibility of a false-positive report of "complete ACL tear" inevitable with MR imaging. CONCLUSIONS: Since conservative treatment is sufficient for incomplete ACL tears, the decision to undertake ACL reconstruction should not be based on MR findings alone

A safe operating space for humanity

The article presents a study that investigates on the importance of identifying and quantifying planetary boundaries to prevent human activities in affecting environmental condition. The author states the industrial revolution and advancement in human civilization has caused the unstability of the environmental state that is less conducive for humans to live and affect their health condition. The author notes that planetary boundaries served a control variables to secure the safety of its citizen as well as protect the environment from shifting to dangerous levels. It also cites the different planetary boundaries, along with its impact on climate change and Earth system degradation

Thermodynamics of the formation of composite material structures. A review

Composite material structures at nano-, micro-, and meso- levels have been examined. The application of the Gibbs and Hill thermodynamics has allowed researchers to give the physical interpretation of the Laplace pressure for composite materials; to derive the thermodynamic functions describing the particles consolidation; to establish the new phenomenon, namely, metal melt imbibition (MMI), and to define its acting forces, to establish the criterion that allows to determine a direction of a liquid phase migration in a composite body, as well as to predict the final structure of composite materials. For the description of composite material structure, which forms under extreme conditions, it has been necessary to use the nonequilibrium thermodynamics. At the extreme conditions the Prigogine concept of local equilibrium is promising.Изучена структура композиционных материалов на нано-, микро- и мезоуровнях. Используя термодинамику Гиббса и Хилла, исследователи дали физическую интерпретацию давления Лапласа для композиционных материалов; получили термодинамические функции, описывающие процесс консолидации частиц; установили новое явление – поглощение металлических расплавов спеченными композиционными телами (phenomen MMI), определили его движущие силы; обосновали критерий, который позволяет определить направление миграции жидкой фазы в композиционных телах; предсказать окончательную структуру композиционных материалов. Для описания структуры композиционных материалов, которые формируются в экстремальных условиях, предложено применять неравновесную термодинамику. Для этих условий перспективной является концепция локального равновесия, разработанная И. Пригожиным.Вивчено структуру композиційних матеріалів на нано-, мікро- і мезорівнях. Використовуючи термодинаміку Гіббса і Хілла, дослідники дали фізичну інтерпретацію тиску Лапласа для композиційних матеріалів; одержали термодинамічні функції, що описують процес консолідації часточок; виявили нове явище – поглинання металевих розплавів спеченими композиційними тілами (phenomenon MMI) та визначили його рушійні сили; обґрунтували критерій, який дозволяє визначити напрямок міграції рідкої фази в композиційних матеріалах та прогнозувати кінцеву їх структуру. Для опису структури композиційних матеріалів, яка формується в екстремальних умовах, запропоновано застосовувати нерівноважну термодинаміку. Для цих умов перспективною є концепція локальної рівноваги, яка розроблена І. Пригожиним