FE Modelling and Analysis of Beam Column Joint Using Reactive Powder Concrete

Reactive powder concrete (RPC) is used in the beam-column joint region in two out of four frames. Finite element modeling of all specimens is developed by using ABAQUS software. Displacement controlled analysis is used rather than load control analysis to obtain the actual response of the structure. The prepared models were verified by using experimental results. The results showed that using RPC in the joint region increased the overall strength of the structure by more than 10%. Moreover, it also helped in controlling the crack width. Furthermore, using RPC in the joint region increased the ductility of the structures. Comparisons were made by varying the size of the mesh and viscosity parameter values. It was found that by increasing the mesh size and viscosity parameter value, analysis time and the number of steps during analysis were reduced. This study provides a new modeling approach using RPC beam-column joint to predict the behavior and response of structures and to improve the shear strength deformation against different structural loading.

Materials Approach to Improving Asphalt Pavement Longitudinal Joint Performance

Many states are looking for methods to improve longitudinal joint performance of their asphalt pavements, since these joints often fail before the rest of the surface. With their inherently lower density, longitudinal joints fail by cracking, raveling, and potholing because of the intrusion of air and water. Because of their longitudinal joint issues, and after trying several less-than-successful traditional solutions, Illinois Department of Transportation (IDOT) developed a concept to seal the longitudinal joint region, but from the bottom up. Test sections were constructed in 2001 through 2003 to determine how a newly developed material, called longitudinal joint sealant (LJS), would improve joint performance. LJS is a highly polymer-modified asphalt cement with fillers and is placed at the location of a longitudinal joint before paving. As mix is paved over it, the LJS melts and migrates up into voids in the low-density mix, making the mix impermeable to moisture while sealing the longitudinal joint itself. The IDOT test pavements were evaluated after 12 years and found to have longitudinal joints that exhibited significantly better performance than the control joint sections and were in similar or better condition than the rest of the pavement. Laboratory testing of cores showed decreased permeability and increased crack resistance of mix near joints with LJS as compared with similar mix without LJS. The life extension of the joint area is approximately 3–5 years, and the benefit is calculated to be three to five times the initial cost.

Diagnosis and treatment of sacroiliac joint region pain in horses

The sacroiliac joint and pain deriving from this complex region remains poorly understood in horses, although our understanding grows as the body of literature grows. A deeper understanding can be derived from the richer body of literature in human sacroiliac joint pain as the disease processes and biomechanics appear similar in both species. A highly specific and sensitive diagnostic test for this condition does not exist, so equine clinicians have to make presumptive diagnosis based on presenting signs, findings of clinical examination, diagnostic imaging and the response to blocking of the sacroiliac joint region. Many horses with sacroiliac joint region pain have concurrent orthopaedic injury or disease. Treatment is largely based on fundamentals, anecdotal evidence and translation of non-surgical techniques used in humans. Treatment for other orthopaedic conditions can conflict with rehabilitation for sacroiliac joint region pain, necessitating compromise.

Analytical modeling of the shear behavior of reinfored concrete exterior beam-column joints

In reinforced concrete structures, failure of beam-column joint was observed as one of the major causes of damage of those structures during earthquakes. Non-ductile detailing of reinforcement in the joint in terms of inadequate shear reinforcement in the joint panel or insufficient anchorage of the beam bars within the joint region are the main causes of deficiency in the performance of joints during an earthquake. The objectives of this study are to compare different aspects of modeling the nonlinear behavior of exterior beam-column joints and also to propose a new model for the shear behavior of exterior joints. Two well-known computer programs for nonlinear dynamic analysis of the structures DRAIN-2DX (element type 15) and IDARC2D are used. The advantages of using each one for the beam-column joints in the reinforced concrete structures, and the effect of modeling features on the response of beam-column joints are discussed.

Analytical modeling of the shear behavior of reinfored concrete exterior beam-column joints

In reinforced concrete structures, failure of beam-column joint was observed as one of the major causes of damage of those structures during earthquakes. Non-ductile detailing of reinforcement in the joint in terms of inadequate shear reinforcement in the joint panel or insufficient anchorage of the beam bars within the joint region are the main causes of deficiency in the performance of joints during an earthquake. The objectives of this study are to compare different aspects of modeling the nonlinear behavior of exterior beam-column joints and also to propose a new model for the shear behavior of exterior joints. Two well-known computer programs for nonlinear dynamic analysis of the structures DRAIN-2DX (element type 15) and IDARC2D are used. The advantages of using each one for the beam-column joints in the reinforced concrete structures, and the effect of modeling features on the response of beam-column joints are discussed.

Effects of horse housing on musculoskeletal system post-exercise recovery

This study examined the effects of two housing systems (control housing and loose housing) on musculoskeletal condition during recovery from race-like exercise in Standardbred horses. The hypothesis was that a loose housing system provides better conditions for musculoskeletal recovery than the control housing. Eight adult geldings (mean age 11 years) were used in a study with a cross-over design, with the control housing (CH) and loose housing (LH) treatments each run for 21 days. The horses had ad libitum access to forage and performed two similar race-like exercise tests (ET), on day 7 and day 14 in each treatment. Blood samples were collected before ET, at finish line, and at 7, 22, and 44 h of recovery and analysed for the muscle enzyme activities of creatine kinase and amino transferase. Before and three days after ET, hind leg fetlock joint region circumference and diameter, joint range of motion in right hock and carpus, mechanical nociceptive threshold in back muscle, and movement asymmetry were recorded. Overall circumference and overall diameter of hind fetlock joint region were lower in LH horses than CH horses (P=0.045 and P=0.017, respectively), but no other differences were observed. In conclusion, a loose housing system did not alter the recovery of musculoskeletal condition other than preventing a post exercise enlargement of the circumference and diameter of the hind fetlock joint region.

Influence of the 5′-terminal sequences on the 5′-UTR structure of HIV-1 genomic RNA

The 5′-UTR of HIV-1 genomic RNA is known to form specific structures and has important functions. There are three 5′-terminal sequences, G1, G2 and G3, with different localizations in the cell and virion particles as well as different efficiencies in translation and reverse transcription reactions. In the present study, the structural characteristics of the joint region between the TAR and PolyA stems was analysed, and it was found that small differences in the 5′-terminus affect the conformational characteristics of the stem-loop structures. In the G1 form, the two stems form a coaxial stem, whereas in the G2 and G3 forms, the two stems are structurally independent of each other. In the case of the G1 form, the 3′-flanking nucleotides of the PolyA stem are included in the stable coaxial stem structure, which may affect the rest of the 5′-UTR structure. This result demonstrates that the local conformation of this functionally key region has an important role in the function of the 5′-UTR.

Experimental investigation of exterior reinforced concrete beam - column joints strengthened with hybrid FRP laminates

In the present study, an experimental and theoretical investigation is carried out on the reinforced concrete exterior beam-column joints strengthened with the hybrid fibre reinforced polymer (HFRP). The effect of reversible distress that develops in the joint region due to seismic force is determined experimentally by applying reverse cyclic loading on the tip of the beam. In theoretical analysis, the shear strength of strengthened joints was determined, and satisfactory correlations with experimental results were established. Hence, the proposed physical model provides valuable insight into the strength behaviour of the joints.

Structural Insight into the Two-Step Mechanism of PAI-1 Inhibition by Small Molecule TM5484

Plasminogen activator inhibitor-1 (PAI-1), a key regulator of the fibrinolytic system, is the main physiological inhibitor of plasminogen activators. By interacting with matrix components, including vitronectin (Vn), PAI-1 plays a regulatory role in tissue remodeling, cell migration, and intracellular signaling. Emerging evidence points to a role for PAI-1 in various pathological conditions, including cardiovascular diseases, cancer, and fibrosis. Targeting PAI-1 is therefore a promising therapeutic strategy in PAI-1-related pathologies. A class of small molecule inhibitors including TM5441 and TM5484, designed to bind the cleft in the central β-sheet A of PAI-1, showed to be potent PAI-1 inhibitors in vivo. However, their binding site has not yet been confirmed. Here, we report two X-ray crystallographic structures of PAI-1 in complex with TM5484. The structures revealed a binding site at the flexible joint region, which is distinct from the presumed binding site. Based on the structural analysis and biochemical data we propose a mechanism for the observed dose-dependent two-step mechanism of PAI-1 inhibition. By binding to the flexible joint region in PAI-1, TM5484 might restrict the structural flexibility of this region, thereby inducing a substrate form of PAI-1 followed by a conversion to an inert form.