Hinge Area Research Articles

Energy dissipation capacity of precast concrete beam-column joint connected by double notch subjected to cyclic lateral loading

This paper presents the experimental investigation of full-scale precast concrete beam-column connections subjected to cyclic lateral loading. The specimen consists of three models. Two of which are precast beam-column connections and one is monolith. The precast and monolith specimen were designed for the same strength. The cross-sectional dimensions of the beam 250 mm x 300 mm and column 300 mm x 300 mm. Connections are placed in plastic hinge area, with a distance of h (beam height) from the face of the column which is expected to occur first destruction. Precast construction joints are distinguished, with 3 different models, namely monolith, double notch type 1 (STR-1), and double notch type 2 (STR-2). Maximum load capacity, hysterical behavior and energy dissipation are measured, and capacity is compared. The results showed that beam-column joint STR-2 are better able to absorb energy than beam column joint monolith and beam-column joint STR-1. Kumulative energy dissipation of monolith about 9333.07 kN-mm, STR-1 is 8336.76 kN-mm, and STR-2 is 10162.52 kN-mm. The use of dual notch connections (STR-1 and STR-2) provides satisfactory performance, which is marked by meeting the minimum relative energy dissipation ratio at a 3.5% drift according to the ACI Committee 374.1-05. The results show that the STR-2 beam-column connection is more capable of absorbing energy than the monolith beam-column connection and STR-1 beam connection. the value of monolithic cumulative energy dissipation is around 9333.07 kN-mm, STR-1 is 8336.76 kN-mm, and STR-2 is 10162.52 kN-mm. in principle, all three test specimens, monoliths, STR-1 and STR-2 provide satisfactory stability performance under lateral cyclic loads, because they still meet the minimum relative energy dissipation ratio at a deviation of 3.5% according to the ACI Committee 374.1 -05

Numerical simulation of damage patterns in the plastic hinge area of fire protected (SFRM) steel beams and its effect on their fire resistance

AbstractSprayed Fire‐Resistive Materials (SFRMs) are low strength, brittle materials used as passive fire protection on steel structural members. Their main drawback is that they can develop significant damage when the underlying steel member is subjected to mechanical deformations. The current study addresses numerically the damage patterns of the passive fire protection that could arise at the plastic hinge area of IPE steel beams and their effect on the fire resistance of the member. Initially, a numerical method that combines the smeared crack model and the discrete crack concept is implemented for the simulation of the mechanical behavior of the fire protective material and the prediction of the damage it sustains. The results of the mechanical analysis, considering the parameters of cross‐section height, SFRM thickness, monotonic or cyclic loading and presence of geometric initial imperfections, suggest that the damage pattern, which is a result of the combination of interface delamination and crack formation in the body of the material, can be categorized in two basic forms. In the sequel, a heat transfer analysis is conducted on the steel beams, under standard ISO‐834 thermal load, taking into account the damage derived by the mechanical analysis, in order to assess the reduction in the fire resistance of the beams, compared to the corresponding beams with an intact fire protection layer or without any fire protection.

Analysis of multiple failure behaviors of steering knuckle ball hinge of multi-axle heavy vehicle

The ball hinge is a key component of the vehicle chassis that connects the steering knuckle and the control arm. This study analyzed the multiple failure behaviors of the chassis ball hinge. First, according to the macroscopic failure characteristics of the ball hinge, the analysis method of the fault tree was adopted to identify the possible cause of the failure. The axial force and radial force of the ball joint were obtained by simulating the force of the vehicle under the typical extreme conditions. The stress distribution of the ball pin was obtained by finite element analysis of the ball joint. The calculation results are consistent with the fatigue crack position of the ball hinge. Then the ball hinge was disassembled. On the one hand, the macro morphology was observed. On the other hand, the chemical composition and microstructure of the ball pin material were analyzed by scanning electron microscope and infrared spectrum analyzer. Finally, the macro morphology and microstructure of the ball joint seat, ball bowl, dust cover and other parts matched with the ball hinge were analyzed to further verify the failure reason of the ball hinge. The results showed that the dust cover of the ball hinge was firstly aged and cracked, and the external dust and particles enter into the friction contact area of the ball hinge, which caused the ball pin and ball bowl to be stuck. During the driving process of the vehicle, the ball pin undergoes unidirectional bending fatigue fracture in the stress concentration area at the root of the conical surface.

Seismic performance of precast concrete columns with prefabricated UHPC jackets in plastic hinge zone

The plastic hinges of precast concrete columns with grouted sleeves commonly occur at the column-footing connection regions, leading to difficulties in the repair and rehabilitation of precast concrete structures after catastrophic events. In this paper, new structural details are proposed to strengthen the plastic hinge area of precast columns by using local prefabricated UHPC jackets. Three specimens were tested under reversed cyclic loading to evaluate the seismic performance of the precast column strengthened with local prefabricated UHPC jackets. The results show that the specimen with the proposed prefabricated UHPC jackets shifts the damaged areas away from the column-footing connection region and achieves comparative seismic performance to that of the monolithic reference specimen. The plastic hinge length of the column strengthened with a local prefabricated UHPC jacket can be estimated by the plastic hinge length models for monolithic concrete members.

Abstract 1469: TPX-0131, a potent inhibitor of wild type ALK and a broad spectrum of both single and compound ALK resistance mutations

Abstract Three generations of ALK inhibitors are approved for the treatment of ALK+ NSCLC but their efficacy is often limited by ALK resistance mutations. The solvent front mutation G1202R and gatekeeper mutation L1196M are major resistance mechanisms to the first two generations of inhibitors. Patients treated with second generation inhibitors are reported to progress with multiple mutations on separate alleles (mutations in trans). In contrast, 35 - 48% of patients treated with lorlatinib progress with multiple mutations on the same allele (compound mutations, mutations in cis). TPX-0131 is an ALK inhibitor with a compact macrocyclic structure designed to bind completely within the ATP binding boundary and overcome a spectrum of single and compound ALK resistant mutations. TPX-0131 was profiled against previous generations of ALK inhibitors both in vitro and in vivo. In biochemical assays, TPX-0131 potently inhibits (IC50 <10 nM) wild type (WT) ALK and 26 ALK mutations (single and compound). Cell proliferation assays of WT, single mutations, and compound mutations were used to evaluate TPX-0131 relative to previous generations of ALK inhibitions (crizotinib, alectinib, brigatinib, ceritinib, lorlatinib). TPX-0131 is more potent against WT EML4-ALK (IC50 = 0.4 nM) than previous generations of ALK inhibitors (2-fold, lorlatinib; 10 - 30-fold, second generation inhibitors; >100-fold, crizotinib). TPX-0131 potently inhibits EML4-ALK harboring a G1202R solvent front mutation (IC50 = 0.2 nM) which is >100-fold more potent than previous generations of ALK inhibitors. TPX-0131 potently inhibits ALK harboring a gatekeeper mutation (IC50 = 0.5 nM) and is >10-fold more potent than previous generations of ALK inhibitors. TPX-0131 potently inhibits ALK with a L1198F hinge area mutation (IC50 = 0.2 nM) which is 87 - 3000-fold more potent than previous generations of ALK inhibitors. TPX-0131 is the most potent inhibitor against nine EML4-ALK double and triple compound mutations (6 with IC50 < 1 nM, 3 with IC50 1.6 - 14.9 nM). Evaluation of ALK phosphorylation as a pharmacodynamic marker in tumors showed potent ALK inhibition by TPX-0131 that correlated with TPX-0131 exposure. In Ba/F3 cell-derived xenograft tumor models with EML4-ALK mutations, TPX-0131 (2, 5, 10 mg/kg BID) demonstrated robust anti-tumor activity in the G1202R model (64%, 120%, 200% TGI), G1202R/L1198F model (complete regression, all doses), and G1202R/L1196M model (44%, 83% and 200% TGI). In contrast, lorlatinib (5 mg/kg BID) caused 31% TGI in the G1202R/L1198F model and did not have statistically significant TGI in the G1202R/L1196M model. Taken together, TPX-0131 is a next generation ALK inhibitor that has preclinical potency against WT ALK as well as a broad spectrum of acquired resistance mutations, especially compound mutations, which currently lack any effective ALK inhibitor therapy. Citation Format: Brion W. Murray, Dayong Zhai, Wei Deng, Evan Rogers, Xin Zhang, Jane Ung, Vivian Nguyen, Han Zhang, Maria Barrera, Ana Parra, Jessica Cowell, Dong Lee, Herve Aloysius. TPX-0131, a potent inhibitor of wild type ALK and a broad spectrum of both single and compound ALK resistance mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1469.

Seismic performance of fabricated concrete piers with grouted sleeve joints and bearing-capacity estimation method

The seismic performance and design method of fabricated concrete bridge piers limit their applications in complex and harsh environments. In this study, a continuous bridge pier in an 8-degree seismic fortification intensity area was considered as a prototype. Two 1/3-scale models were designed and manufactured. The specimens were connected via a grouted sleeve connections (SFP) and a grouted sleeve prestressing tendon composite connections (SSFP), respectively. Moreover, a cast-in-place 1/3-scale model (reinforcement concrete pier, RCP) was designed as a comparison specimen. Quasi-static experiments were performed on these three specimens. The seismic performance of the specimens was analysed according to the failure phenomena, bearing capacity, displacement ductility, stiffness, energy-dissipation capacity, and residual deformation. On these basis, a bearing-capacity estimation method for SFP (including SSFP) was developed and validated. The results indicated that the damage to the SFP and SSFP mainly accumulated along the top and bottom of the sleeves. The plastic hinge area of the SFP and SSFP moved up or down. Thus, the damage to the SFP and SSFP was concentrated at the joints. Cracks first occurred at the seam of the two fabricated specimens when the loading drift was relatively small. Then, the concrete at the loading edge of the joints was crushed. Furthermore, the longitudinal bars yielded and broke. Finally, the specimens failed. Compared with the RCP, the SFP and the SSFP had larger yield and ultimate displacements. The bearing capacities of the RCP and the SFP were similar. However, the bearing capacity of the SSFP was significantly higher. The bearing capacities of the SFP and SSFP did not decrease significantly before the specimens failed. Compared with the RCP, the SFP had a lower initial stiffness, a lower stiffness degradation rate, similar displacement ductility, smaller residual displacement, and less cumulative energy dissipation. The SSFP was better than the SFP with regard to the displacement ductility, initial stiffness, and cumulative energy dissipation. Thus, the SFP and SSFP can satisfy the seismic requirements of high-intensity areas. The proposed bearing-capacity estimation method can be used for the seismic design and evaluation of SFPs and SSFPs.

Characteristic localization patterns of thrombus on various brands of bileaflet mitral mechanical heart valves as assessed by three-dimensional transesophageal echocardiography and their relationship with thromboembolism.

Three-dimensional transesophageal echocardiography (3D-TEE) provides detailed images of prosthetic valve thrombosis (PVT). However, data regarding PVT localization patterns based on 3D-TEE and their association with clinical findings among various bileaflet mitral prosthetic valve brands is lacking. The locations of thrombi were classified into 4 groups according to hinge and annulus involvement based on 3D-TEE: ring-like PVT involving entire mitral annulus (type-1), PVT involving peri-hinge(s) region and extends through some part of the annulus (type-2), PVT involving mitral annulus without involving hinge(s) region (type-3), and PVT involving only (peri)hinge(s) area (type-4). This study was conducted in 265 patients (male: 71, mean age: 46.3 ± 12.7years) with mitral PVT, including 150 St Jude Medical (SJM), 65 Carbomedics, 29 Medtronic ATS open-pivot, and 21 Sorin bileaflet mechanical valves. There was a significant difference in most common PVT localization patterns between different prosthetic valves (type-1 for Carbomedics and Sorin; type-2 for SJM and type-3 for ATS valves; p < 0.001). Additionally, PVT involving only (peri)hinge region(s) (type-4) was mostly observed in patients with SJM valves (18%). (Peri)hinge(s) area involvement was observed in the majority of study patients (78.1%). In patients who presented with thromboembolism, the most common PVT localization pattern was type-1 (53%). Increased age, low international normalized ratio on admission, PVT with a mobile part > 2mm, type-1 and type-4 PVT were associated with thromboembolic events. In conclusion, thrombus can be displayed in distinct locations in several types of bileaflet mechanical valves due to different design, hinge and pivot mechanisms, which can be complicated with thromboembolic events.

Anti-Seismic Test Study on the Grid-Tube-Type Double Steel Plate and Infilled Concrete Composite Shear Wall

In this paper, three test models were cast about the grid -tube- type double steel plate and infilled concrete composite shear wall, the horizontal low cyclic loading test was carried out, and hysteresis curves and skeleton curves were got under different coaxial compression ratios. The results show that the new composite shear wall has many advantages, such as full hysteresis curve, high bearing capacity, high ductility and high energy dissipation capacity. Under the large displacement angle of 1/25 and cyclic loading of 80 times, the plastic hinge area still maintains the large stiffness and bearing capacity, which can effectively prevent the collapse of the structure under the action of a major earthquake. New composite shear wall has good seismic performance, which can realize the design requirements of high axial compression ratio, high ductility and thin thickness walls.

Monocortical fixation for locking plate distal screws does not impair mechanical properties in open-wedge high tibial osteotomy

BackgroundThe neurovascular bundle containing the deep peroneal nerve has a potential risk of injury during open-wedge high tibial osteotomy (OWHTO), particularly due to drilling for bicortical fixation at distal screw holes. Therefore, monocortical fixation is recommended for distal fixation of a long locking plate as long as good stability is ensured. The purpose of this study was to analyse the biomechanical properties of monocortical fixation of distal locking screws for OWHTO.MethodsThree-dimensional models of bone and fixation materials simulating OWHTO were created using computed tomographic data of patients and material data of a T-shaped long locking plate and screws. Three of the four distal screws of the locking plate were chosen for a bicortical fixation or monocortical fixation procedure. In addition, loss of correction was assessed by measuring the medial proximal tibial angle (MPTA) in patients who underwent OWHTO with two bicortical and two monocortical distal fixation screws at 1 month and 1 year after surgery.ResultsNo significant differences in stress were observed in either the normal or osteoporotic bone model between the monocortical and bicortical fixation models, including in the area of the lateral hinge at the osteotomy site.Furthermore, there were no significant differences in MPTA between the early post-operative period and 1-year follow-up.ConclusionsThe monocortical fixation method for three distal screws of the locking plate did not worsen the mechanical properties of fixation for OWHTO using a long locking plate with four proximal and four distal screws. In actual surgery, the number of distal bicortical screws should be reduced based on the patient’s condition, taking into account the risk of lateral hinge fracture and unexpected surgical complications. Using at least two bicortical screws would be practical considering the various factors related to reduced fixing ability.

Medial Opening Wedge High Tibial Osteotomy in Knee Osteoarthritis—A Biomechanical Approach

This paper provides an analysis from a biomechanical perspective of the medial opening wedge high tibial osteotomy surgery, a medical procedure commonly used in treating knee osteoarthritis. The aim of this research is to improve the analysed surgical strategy by establishing optimal values for several very important parameters for the geometric planning of this type of surgical intervention. The research methods used are numerical and experimental. We used finite element, a numerical method used to study the intraoperative behavior of the CORA area for different positions of the initiation point of the cut of the osteotomy plane and for different correction angles. We also used an experimental method in order to determine the maximum force which causes the occurrence of cracks or microcracks in the CORA area. This helped us to determine the stresses, the maximum forces, and the force-displacement variations in the hinge area, elements that allowed us to identify the optimal geometric parameters for planning the surgery.

Comparison between Rafidhiya and Shuaiba Domes within the properties of Mishrif Formation in Zubair Field; the implication of structural Geology and petrophysical analyses

The current study combined both concepts of structural geology and petrophysical to understand the structural feature of Mishrif Formation and its implication on the petrophysical characterization of the formation in Shuaiba and Rafidhiya Domes (or culminations) in Zubair Field. Shuaiba and Rafidhiya are adjacent domes and these domes belong to the same Field but the domes separated by saddle may related to Basra – Zubair basement fault.&#x0D; The domes have different petrophysical properties of Mishrif Formation; consequently, influenced in water and oil saturation. Therefore, the study tries to understand the structural and petrophysical position of Mishrif Formation of the domes. The structural analysis included geometric and genetic analysis, whereas petrophysical analysis used open hole logs interpretation to determine the petrophysical characteristics (especially the distribution of porosity, permeability, and water saturation.&#x0D; It was concluded that may a variation in porosity and permeability of Mishrif Formation for Shuaiba and Rafidhiya domes because each dome was formed by a different folding mechanism effected on the petrophysical properties. The structural geology analysis detects that may be Shuaiba dome formed by bending fold mechanism (vertical force of salt structure), while Rafidhiya dome by buckling fold mechanism (parallel force of collision of Arabian and Eurasian plate). These mechanisms may directly be affected in permeability distribution, and consequently on oil and water saturation of Mishrif Formation. Thus, Shuaiba Dome has thinning in hinge area and extensional force leads to create fractures and karst phenomena, and as a result, high permeability in upper Mishrif. On the contrary, Rafidhiya Dome has a thickening feature and there is no indication of karst phenomena and low permeability. Therefore, the Mishrif of Shuaiba dome permeable and oil-saturated, while, it flooded with water in Rafidhiya Dome. The disconnection in reservoir pressure confirmed by difference in initial reservoir pressure of Mishrif Formation of Shuaiba Dome and recent reservoir pressure of Mishrif Formation of Rafidhiya Dome

THE SEISMIC PERFORMANCE OF PRECAST BRIDGE PIERS WITH GROUTED SLEEVES

The grouted sleeves embedded in precast column bodies were taken as the research object. The mechanical behavior of the column-to-footing joint and the influence on the overall seismic performance of this kind of bridge piers were theoretically analyzed. A quasi-static test of precast bridge piers with grouted sleeves was carried out. The difference between the seismic performance of the cast-in-place piers and the precast bridge piers with grouted sleeves was compared by a numerical simulation. The influence of different sleeve diameters and lengths on the seismic performance of the bridge piers was also investigated. The results show that the precast piers with grouted sleeves were easy to form a rigid region in the connecting section due to the large rigidity of the sleeves, and that the redistribution phenomenon of the curvature occurred in the columns, resulting in an increase in the curvature and rebar strain concentration adjacent to the end of the sleeves. In addition, the precast bridge piers with embedded grouted sleeves in the plastic hinge area were found to have a reduced displacement capacity as compared to cast-in-place piers with the same reinforcement. This phenomenon was more serious when a larger sleeve diameter was adopted. The larger the diameter and the longer the length of the sleeves, the more obvious the strain concentration at the joint, which resulted in the transformation of the final failure form of the pier from the traditional concrete failure in the plastic hinge area to steel fracture in the joint at the bottom of the pier.

Experimental research on seismic performance of precast cogging high-strength bolt composite joint and influence of its arrangement location

The connection of precast joints is an important factor that affects the seismic and endurance performance of precast concrete structures. Currently, the seismic performance of existing precast joints cannot satisfy the application requirements of complex and harsh environments. This paper proposes a cogging high-strength bolt composite joint (C-HSB joint), and introduces its main components and assembly methods. Two precast beam-column joint (B-C joint) specimens are designed and manufactured using C-HSB joints. The C-HSB joints are arranged outside (SJ2) and inside (SJ3) the plastic hinge area of the beam. For comparison, a B-C joint specimen using a traditional cogging joint (T-C joint) is also designed and manufactured. The T-C joint is arranged outside of the plastic hinge area of the beam (SJ1). Then, quasi-static tests of these three specimens are performed. The seismic performance of the C-HSB and T-C joints are systematically analysed through the following parameters: damage phenomenon, bearing capacity, displacement ductility, rigidity deterioration, energy dissipation, operating state of the cogging seam, and bond-anchorage performance of rebar. Moreover, the influence of the arrangement location and HSB settlement of the C-HSB joint is discussed in detail. The results show that cogging can limit the development of seam cracks and improve the shear capacity of the joint. The HSB can delay the seam cracking, improve the bond-anchorage performance of rebar, and increase the crack resistance and self-resetting capacity of joints. The C-HSB joint can delay the development of seam cracks. The longitudinal rebar of the specimen can utilise more effectively using a C-HSB joint. The location of the C-HSB joint significantly affects the failure mode of the specimen. The internal arrangement (inside the plastic hinge area) of the C-HSB joint will induce the upward motion of the beam plastic hinge and exacerbate the core area damage. The external arrangement (outside the plastic hinge area) will increase the bearing capacity and energy dissipation of the specimens, and the rigidity deterioration will also be slowed. Compared with the C-HSB joint, the T-C joint has a lower displacement ductility, lower energy dissipation, and more rapid rigidity deterioration. The seismic performance of the T-C joint is significantly inferior. The C-HSB joint can be applied to precast concrete structures under complex and harsh environments. The external arrangement (close to the upper boundary of the plastic hinge area) of the C-HSB joint is a better choice.

Evidence that more than a third of Paleozoic articulate brachiopod genera (Strophomenata) lived infaunally

AbstractThe Strophomenata, which includes two large orders, the Strophomenida and Productida, is the largest group of Paleozoic brachiopods. Nearly all uncemented strophomenatans possessed an unusual concave brachial valve. Most of these have been considered to have lived epifaunally, but had they rested on the seafloor, not only would they have faced intense predation, but their physical instability would have been fatal. I conclude that nearly all strophomenatans, like similar concavo-convex pectinid bivalves, lived infaunally by ejecting water to create a pit into which they descended, to be protected by sediment covering the concave valve. Strophomenatans have been discovered with this sediment preserved in place. If exhumed and turned upside down, a strophomenatan could have righted itself by squirting water. Many productides had anchoring spines, and some had hinge areas with stabilizing flanges. Small spines on the brachial valves of some productides served to trap disguising sediment. Evolutionary loss of hinge teeth within both the Strophomenida and Productida reduced the friction of valve clapping. Partly because of their slender shape, strophomenides were typically more vulnerable to exhumation than productides. Strophomenides also ejected water less effectively than productides and would have been less adept at righting themselves. The virtual disappearance of the strophomenides during the Devonian can be attributed to their vulnerability to intensifying benthic bulldozing and predation. The success of the productides during the late Paleozoic can be attributed to their relatively deep sequestration in the sediment and ability to right themselves and reburrow effectively when exhumed and overturned.

Paleostress Analysis of Chia Gara Structure in Dohuk Area, Northern Iraq

The use of Right dihedral method, Lisle graph, and Mohr diagram allows the analysis of the paleostress. Fault slip data were measured for eighteen data of two stations located within Chia Gara structure in Dohuk area in the High Folded Zone, Northern Iraq. Depending on Mohr diagram, Bott equation, and vertical thickness, the magnitudes of the paleostress at the time of the tectonic activity were determined. Firstly, Georient Software was used to estimate the orientation of the paleostresses (σ1, σ2 and σ3). Secondly, using the rupture –friction law, taking into account the depth of the overburden, the vertical stress (σv) was calculated to determine the magnitude of the paleostresses in the study area. The values in station one (hinge area, eight data) were σ1=7100, σ2=4121.5, and σ3=1143 bars, whereas the values in station two (the north limb of structure, ten data) were σ1=3740, σ2=1585, and σ3=570 bars. The high magnitudes of the principal stress axes may refer to the active tectonic events which led to the deformation of the area during the Mesozoic Era and the Tertiary period. The study area shows the existence of two types of the faults, the first type is the reactivated faults, the poles of which lie between the sliding line and Mohr envelope. The second type is the inactive faults, with poles lying on the great circle of Mohr diagram

The "Yogurt" Technique for Descemet Membrane Endothelial Keratoplasty Graft Preparation: A Novel Quick and Safe Method for Both Inexperienced and Senior Surgeons.

To describe and evaluate the efficacy and safety of a novel technique to prepare Descemet membrane endothelial keratoplasty (DMEK) donor grafts using a newly designed partial-thickness hinge punch. The novel punch has a circular guarded blade missing 1 clock hour, creating an uncut hinge on the donor cornea. In addition, 2 straight cuts are made by the punch perpendicular to the edge of trephination toward the trabecular meshwork in the hinge area. After the donor corneoscleral rim is positioned endothelial side up, a partial-thickness trephination is performed avoiding any rotational movements. Descemet membrane is lifted from Schwalbe line in the hinge area, and DMEK graft is peeled after desired marking without further preparation. Three surgeons of different experience levels on DMEK (senior/independent/fellow) initially applied the new technique in 18 research corneas, divided into equal groups. Two failures in graft preparation were noted, defined as radial tears extending ≥0.5 mm. The mean preparation time was 6.21 ± 1.45 minutes. No statistically significant differences were noted in success rate, duration, and endothelial cell loss (ECL) between surgeons (P > 0.05). ECL was evaluated as an average of 5 readings on randomly selected graft areas, not including graft periphery. Fifteen additional research corneas were stripped by 1 single user in an eye bank setting. No tissue loss was recorded, whereas ECL and mortality rate remained unaffected after preparation (P = 0.64 and P = 0.72, respectively). This new DMEK graft preparation technique, simulating the opening of a yogurt cup, seems to be a safe and an efficient method, providing shorter preparation time and low failure rates independent of surgeon's experience level.

The influence of water temperature, salinity and food availability on nacre deposition rates in shells and pearls of Japanese and hybrid pearl oyster, Pinctada fucata ( )

The objectives of this study were to 1) determine the influence of environmental factors (water temperature, food availability [chlorophyll-a], salinity) on nacre deposition rate and tablet thickness at different positions in shells of two strains of pearl oyster, Pinctada fucata (Gould, 1850)—one from Japan, and one a Hybrid between this Japanese strain and another from China; 2) compare nacre deposition rates and tablet thickness in different shell positions within and between these two pearl oyster strains; and 3) determine relationships between shell nacre deposition rate and tablet thickness in host oysters of these two strains with those of their pearls. Nacre and tablet thickness were measured at three positions along the mantle pallial line (anterior, middle, and posterior), and one position close to the hinge, on the left valve of each oyster. Water temperature and chlorophyll-a were positively correlated (p < .001, Spearman's rho >0.75) and salinity was negatively correlated (p < .001, Spearman's rho < −0.7) with nacre deposition rate at all shell positions in both pearl oyster strains. Only water temperature below 13 °C influenced nacre tablet thinning. Significant differences in total nacre deposition occurred between the four sampling positions on the shell in both strains (p < .001), with deposition at the hinge area the slowest for both Hybrid (373.212 μm) and Japanese (569.248 μm) oysters. Nacre tablet thickness in the middle position on the shell increased most steadily over time, and was thinnest in the coolest months (0.151 μm and 0.167 μm for Hybrid and Japanese oysters, respectively). No significant difference (p > .05) in nacre tablet thickness was apparent between strains. Correlation analysis of nacre deposition rate between the shell and pearls showed that all shell positions were highly correlated with their respective pearls (p < .001, Spearman's Rho >0.75). Environmental factors influence shell nacre deposition and thickness, and because shell nacre deposition is related to pearl nacre, pearl growth also. This influence varies in different shell positions, with nacre deposition in the posterior position on the shell the fastest, and the middle position showing the most stable and thin nacre tablet. Japanese pearl oysters exhibit better nacre deposition than Hybrid oysters and would be more appropriate as host oysters in Ago Bay, Japan, should culture occur in environmental conditions comparable to those in this study.

Oxygen isotope disequilibrium in the juvenile portion of oyster shells biases seawater temperature reconstructions

For decades, bivalve shells have constituted one of the most common supports for paleoclimatic archives based on stable isotope approaches. In this work, we conducted chemical marking and recapture techniques to study the fluctuation of δ18O values of oyster shells of the species Magallana gigas reared in natural environment in Normandy (France) for two years. The results were compared to the continuous monitoring of temperature and salinity and monthly records of seawater δ18O. Isotopic measurements were performed on the hinge area that regroups the whole life of the oysters. Here we demonstrate that oysters mineralized their shells with no significant growth breaks during the two-years experiment, even at temperatures below 6 °C. The results confirm that adult oysters (i.e. > 1 yr) mineralized their shells at equilibrium. However, juvenile specimens exhibit a strong isotopic disequilibrium, with a maximum shift of the δ18O values of 3‰ in winter, likely due to kinetic isotope effects. This corresponds to a reconstructed temperature up to 13 °C warmer than expected. This work indicates that although these oyster shells can be used as an accurate archive of (paleo)environmental conditions, the shell portion mineralized during the juvenile stage (i.e. < 1 yr) should be avoided for paleotemperature reconstructions. Given the wide use of bivalve shells as environmental archives, similar studies on others species are required.

Infiltrations rachidiennes autres que lombaires

Spinal steroid injections are much less frequently performed at the thoracic or cervical levels than at the lumbar spine. Preoperative workup should include a clinical and para-clinical imaging evaluation to detect the inflammatory targets. At the thoracic level, steroid injections of the costo-transverse or costo-vertebral or posterior (or zygapohyseal) joints, unilateral or bilateral can be performed. The anatomo-clinical concordance can best be obtained by anesthetic blocks. For this injection, a particulate corticosteroid (prednisolone acetate) or non-particulate corticosteroid (dexamethasone) may be used. Thoracic epidural injections do not have indications in rheumatology. In our opinion, epidural injections should not be performed at the cervical level, Indications of steroid injections of the zygapohyseal joints at the cervical level should be limited to cases of cervical neuralgia resistant to conservative treatment, selected in a multidisciplinary collaborative meeting, after checking that the injection site is distant from a operated level and that there is no large veins facing the articular mass at MRI at the site of planned injection. The injections of the joint in the area of the cervico-occipital hinge (in particular C1-C2 lateral joint) must be decided in a multidisciplinary meeting and the patient must be informed of the risks of serious neurological accident.

Parametric Analysis on Seismic Performance of Hybrid Precast Concrete Beam‐Column Joint

In this paper, a nonlinear finite element (FE) analysis of high‐performance hybrid system (HPHS) beam‐column connections is presented. The detailed experimental results of the ten half‐scale hybrid connections with limited seismic detailing have been discussed in a different paper. However, due to the inherent complexity of HPHS beam‐column joints and the unique features of the tested specimens, the experimental study was not comprehensive enough. The new connection (HPHS) detail suggested in this study is characterized by ductile connection, steel connectors, and engineered cementitious composite (ECC) which is a kind of high‐performance fiber reinforced cement composite with multiple fine cracks (HPFRCCs). Therefore, in this paper, FE analysis results are compared with experimental results from the cycle tests of the two specimens (RC and PC) to assess model accuracy, and detailed model descriptions are presented, including the determination of stiffness and strength. The critical parameters influencing the joint’s behavior are the axial load on column, beam connection steel plate length, inner bolt stress contribution, and plastic hinge area.