High-density speckle contrast optical tomography of cerebral blood flow response to functional stimuli in the rodent brain

Noninvasive, three-dimensional, and longitudinal imaging of cerebral blood flow (CBF) in small animal models and ultimately in humans has implications for fundamental research and clinical applications. It enables the study of phenomena such as brain development and learning and the effects of pathologies, with a clear vision for translation to humans. Speckle contrast optical tomography (SCOT) is an emerging optical method that aims to achieve this goal by directly measuring three-dimensional blood flow maps in deep tissue with a relatively inexpensive and simple system. High-density SCOT is developed to follow CBF changes in response to somatosensory cortex stimulation. Measurements are carried out through the intact skull on the rat brain. SCOT is able to follow individual trials in each brain hemisphere, where signal averaging resulted in comparable, cortical images to those of functional magnetic resonance images in spatial extent, location, and depth. Sham stimuli are utilized to demonstrate that the observed response is indeed due to local changes in the brain induced by forepaw stimulation. In developing and demonstrating the method, algorithms and analysis methods are developed. The results pave the way for longitudinal, nondestructive imaging in preclinical rodent models that can readily be translated to the human brain

Age-Related Skeletal Muscle Atrophy in Humans: An Immunohistochemical and Morphometric Study

The aim of this study was to determine age-related changes in three human muscles with different function and location in the body. The cross sectional area and the percentage of fibers type I, type IIA and type IIX were studied in vastus lateralis, deltoideus and external intercostal muscle. Muscle samples were obtained from 30 male subjects, aged 20–80 years. Fiber types were defined immunohistochemically, using monoclonal antibodies specific for type I, type IIA and type IIX fibers. Cross sectional area of muscle fibers was analyzed morphometrically by computerized image analysis. All muscle fiber types (I, IIA, IIX) showed the reduction in the fiber size in all three examined muscles. In all muscles the proportion of type I and type IIA was changed, but not in type IIX. With increasing age results showed the increase in proportion of type I, while proportion of type IIA fibers decreased, with vastus lateralis muscle being the most affected. These results suggest that age-related muscle atrophy is not a general phenomenon, and does not affect all muscles equally

Clinical and biochemical characterization of the prothrombin Belgrade mutation in a large Serbian pedigree: new insights into the antithrombin resistance mechanism

Background: The recently reported c.1787G gt A mutation in the prothrombin gene leads to Arg596Gln replacement in the protein molecule (prothrombin Belgrade). This substitution impairs binding of antithrombin to thrombin and results in inherited thrombophilia, known as antithrombin resistance. Objectives: We aimed to elucidate the clinical and biochemical characteristics of thrombophilia associated with antithrombin resistance in a large Serbian family with the prothrombin Belgrade mutation. Patients and methods: Nineteen family members were investigated, among whom 10 were carriers of the c.1787G gt A mutation. In all subjects the clinical phenotype was determined and laboratory investigations of hemostatic parameters were performed. Results: Six out of the 10 mutation carriers developed thromboembolic events, mainly deep venous and mesenteric vein thrombosis. The median age of the first thrombotic event was 26.5 (12-41) years, whereas the incidence rate of first thrombosis was 2.2% per year. In all mutation carriers prothrombin activity was significantly decreased in comparison with non-carriers, clearly distinguishing each group. However, the presence of the mutation did not affect the prothrombin antigen level in plasma. The endogenous thrombin potential was significantly increased in all carriers in comparison with non-carriers, indicating the presence of blood hypercoagulability. Interestingly, levels of D-dimer and the F1+2 fragment were similar in both groups. Conclusions: Although rare, the prothrombin Belgrade mutation represents strong thrombophilia with early onset of thrombosis in the investigated family. According to our results, decreased prothrombin activity may be a simple screening test for detection of this mutation in thrombotic patients

People with physical disability in Serbia: Relationship between internalized stigma, experienced and anticipated discrimination, and empowerment

The aim of present study was to explore relationships between experienced and anticipated discrimination, internalized stigma, and empowerment among people with physical disabilities in Serbia. The convenience sample consisted of persons with different types of physical disabilities. The following scales were administrated: The Discrimination and Stigma Scale, the Internalized Stigma of Mental Illness Scale, and the Boston University Empowerment Scale. An analysis showed that internalized stigma was correlated with experienced and anticipated discrimination and empowerment, while no correlation was found between empowerment and discrimination. People with physical disabilities who experienced and anticipated discrimination are at higher risk of reporting internalized stigma

Optimistic concurrency with OPTIK

We introduce OPTIK, a new practical design pattern for designing and implementing fast and scalable concurrent data structures. OPTIK relies on the commonly-used technique of version numbers for detecting conflicting concurrent operations. We show how to implement the OPTIK pattern using the novel concept of OPTIK locks. These locks enable the use of version numbers for implementing very efficient optimistic concurrent data structures. Existing state-of-the-art lock-based data structures acquire the lock and then check for conflicts. In contrast, with OPTIK locks, we merge the lock acquisition with the detection of conflicting concurrency in a single atomic step, similarly to lock-free algorithms. We illustrate the power of our OPTIK pattern and its implementation by introducing four new algorithms and by optimizing four state-of-the-art algorithms for linked lists, skip lists, hash tables, and queues. Our results show that concurrent data structures built using OPTIK are more scalable than the state of the art

Boosting Transactional Memory with Stricter Serializability

International audienceTransactional memory (TM) guarantees that a sequence of operations encapsulated into a transaction is atomic. This simple yet powerful paradigm is a promising direction for writing concurrent applications. Recent TM designs employ a time-based mechanism to leverage the performance advantage of invisible reads. With the advent of many-core architectures and non-uniform memory (NUMA) architectures, this technique is however hitting the synchronization wall of the cache coherency protocol. To address this limitation, we propose a novel and flexible approach based on a new consistency criteria named stricter serializability ($${\text {SSER}^+}$$SSER+). Workloads executed under $${\text {SSER}^+}$$SSER+ are opaque when the object graph forms a tree and transactions traverse it top-down. We present a matching algorithm that supports invisible reads, lazy snapshots, and that can trade synchronization for more parallelism. Several empirical results against a well-established TM design demonstrate the benefits of our solutio