Structural components designed to absorb energy and shield a more valuable structure ideally require mechanical properties that combine a relatively high load-carrying capacity followed by a practically zero stiffness. This ensures that a specified energy quantity may be absorbed within a limited displacement and that any stress transfer to the valuable structure is minimized. Material damage has been historically mobilized to provide such properties, but this obviously renders such components to be single-use. By contrast, mobilization of elastic instability can also provide the desired combination of properties but without necessarily damaging the material. This reveals an intriguing possibility of such components being potentially repairable and theoretically re-usable with no significant loss in performance. A series of analytical, finite-element and experimental studies are presented for a bespoke mechanical metamaterial arrangement that is designed to buckle sequentially and behave with the desired ‘high strength–low stiffness’ characteristic. It is found that the various axial and rotational stiffnesses associated with the geometric arrangement and its constituent connections may be tuned to provide the desired mechanical behaviour within the elastic range and delay the onset of significant damage, thereby rendering the concept of harnessing instability to be feasible. However, it has also been known for a relatively long time now that the change in stiffness arising from the buckling process can be harnessed for advantageous purposes –4. Indeea, where δ0 represents the necessary deformability for such a system to be effective. However, cellular structures with bespoke geometrical configurations can be designed with a high load-carrying capacity and minimal post-buckling stiffness [δ0, as represented in figure 1b. This can be achieved through material viscoelasticity or through the loss of stiffness due to plasticity [figure 1b, has an initially high stiffness and large load-carrying capacity, followed by a quasi-zero post-buckling stiffness. While the latter (stable) low-stiffness post-buckling response restricts a transfer of large impact forces to the protected structure, the high initial stiffness kpre and high load-carrying capacity maximize the energy absorbency of the system, measured by evaluating the area under the load–displacement curve, without needing a large axial displacement, as would be required for the aforementioned structures made from soft materials. Shan et al. [et al. [Recent world events have brought into sharp focus the need for certain critically important buildings and infrastructure to have protective layers shielding from impact or blast. Therefore, the quest for efficient energy absorbing systems has obtained crucial importance. Although soft materials with a relatively high yield stress would technically be able to perform this task, examples of which are polymeric composites and foam-filled thin-walled structures ,19, theyfigure 1tiffness ,21. Thisasticity . Howeverasticity ,24, wherasticity . The desn et al.  have des [et al.  proposedOf course, lots of experimental and numerical work already exists within the literature on investigating different kinds of metamaterials for enhancing energy absorption and structural isolation performance of protective cellular structures ,29, incl. 2a for the unloaded flint configuration), whereby the in-plane cellular structure initially expands laterally under the compressive load P (figure 2b), to an auxetic arrowhead [figure 2c), which has an effective negative Poisson’s ratio owing to its re-entrant angles and contracts laterally under further compressive displacement Lu and Ll for the upper and lower members, respectively, while the two rigid links within the middle strut have equal lengths of Lm. The original length DE of the lower longitudinal spring is given as a factor of the middle strut length sLm. The initial angles of inclination for the lower and upper links of the arrowhead are αl and αu, respectively, with specific values of these given in P is applied, the changing angles of inclination to the horizontal are c. However, the angle to the vertical created by the buckling of the middle strut links is given as A unit cell configuration, referred to presently as a ‘flint arrowhead’ and shown in figure 2rrowhead  , thus:Lu and Lm can be written in terms of length Ll alongside the initial upper and lower angles αu and αl, respectively,UR is given by:V can be formulated. Invoking the principle of stationary V with respect to the generalized coordinates V through by The equilibrium equations for the flint arrowhead mechanical model, as shown in  δai cf. a and 2c,AUTO-07P . The fol. 2.2. 2.2.1a, the middle strut longitudinal normalized spring stiffness equation . In figuications ; higher b shows the lower in-plane rotational spring stiffness a. The post-buckling stiffness transitions from a clearly negative value to the more favoured quasi-zero stiffness response as c presents the equivalent results while varying the upper rotational spring stiffness Figure 3. 2.2.2i = {1, 2, 3, 4, 5}, since axial stiffness variations across the stack do not affect the behaviour significantly. Similarly, since the The behaviour of five flint arrowhead cells in series is examined primarily to understand the influence of joining cells together on the overall mechanical response of this cellular architecture. Since the joint stiffnesses dictate the fundamental and post-buckling response, as shown in the unit cell case in §2.2.1, these normalized parameters can be selected to provide the desired set of outcomes. Firstly, the normalized axial stiffness parameters are set to be equal, i.e. a, since only cell 1 is triggered, only that branch grows in the negative direction until the first bifurcation where the other branches begin to appear. Similarly, when comparing cells 1 and 3, in figure 5b, the first and second red branches trend in one direction until the second bifurcation point when the remaining branches start trending in the opposite direction. Similar behaviour is observed throughout the different plots and clearly shows the sequential response of different cells within the stack.. 3A dynamic implicit finite-element (FE) method with a quasi-static type loading application is used to analyse all the numerical models presently with two reasons driving this choice. Firstly, dynamic analysis is much more suitable for modelling the snap-through behaviour which often causes the system to flip between static and dynamic responses for various load and displacement combinations as the cell structure jumps from one stable form to another. Secondly, since the system is being considered for energy absorption applications, dynamic FE is much more appropriate for modelling phenomena such as impact or blast, although the accelerations would be significantly higher for such cases and those particular considerations are left for future work. Dynamic analysis features in the commercial FE software ABAQUS  whereby . 3.1E = 2 GPa, which represents the material property of Nylon as that was selected for the tested physical specimens. Since inertial effects are considered, albeit minimally owing to the quasi-static nature of the present study, the material density of Nylon 1150 kg m−3 is used for all models. Four elements per structural member are used, since a mesh convergence study demonstrated that this was sufficient to capture expected deflected shapes [figure 6a with the right end-node pinned, constraining all translational displacements. A displacement-driven load is applied at the left end-node with the addition of a roller boundary allowing only displacement in the x-direction as shown. Rotation about the x-axis is also constrained for both the pinned and roller ends to eliminate twisting of the unit cell under compression, which in practice is unlikely to be a significant issue since the network of cells would make the lattice arrangement torsionally very stiff. The initial inclination angles and lengths are given in figure 2a relates to the axial stiffness of the middle strut, while the transverse spring linking points F to G in figure 2a relates to the bending stiffness of the middle strut to provide its buckling load and model its post-buckling stiffness.Preliminary studies are conducted on a three-dimensional flint arrowhead unit cell under compression, which is a three-dimensional extension of the planar arrowhead geometry considered in the analytical model. To model these unit cells, rigidly connected three-dimensional quadratic three-noded Timoshenko beam elements (B32) are used with circular solid sections with a Young’s modulus d shapes . The bourl, which are 25%, 50%, 75% and 100% of the upper inclined member radii ru, are analysed such that a similar spectrum of results are studied as in the analytical study (rm) as rl and is therefore examined for the four different magnitudes relative to ru, as detailed above. The principal objective for these parametric changes is to determine their effects on the snap-through behaviour of a flint arrowhead and establish a favourable configuration that has an equilibrium response with a high load-carrying capacity and a near-zero post-buckling stiffness. Note also that a small half-sine wave imperfection of amplitude H/1000 is introduced to the middle strut to ensure it buckles, thus avoiding numerical convergence issues occurring when the instability is triggered.The horizontal end-shortening arising from the displacement-driven load on the left is given by Δ. As shown in al study ; a const. 3.2P applied at the left end-node. The central nodes are placed on rollers allowing only horizontal displacement such that global buckling is inhibited since such an instability is unlikely within a stack that is part of a lattice structure; other boundary constraints described for the unit cell case also apply presently.In the analytical study presented in §2.2.2, a stack of five cells were studied to obtain qualitative information on how a stack of multiple cells would behave when loaded axially. For its purpose, a stack of five cells was sufficient in terms of obtaining all the equilibrium paths, understanding their provenance, while avoiding convergence issues that often occur when solving a large system of nonlinear algebraic equations numerically, especially where bifurcating instabilities abound. In the present FE study, labelled as case ‘FS’ in . 3.3Of course, studying a single stack of cells naturally only provides a small set of the interactions between individual members and cells that can occur within an entire lattice. Hence, it is necessary to model full lattices, particularly if the FE models need to be compared with physical tests. geometrical grading to improve the mechanical response by engineering a controlled buckling sequence , as was achieved in the analytical model . This can be attributed principally to the increase in axial and bending stiffness of the middle strut as its radius is increased. The middle strut is pivotal in the initial phase of the load–displacement response since it is under direct compression and therefore is the most effective in resisting the external load. However, since the lower members also govern the geometrical phase transition from conventional to auxetic behaviour of the unit cell, increasing these inclined member radii also increase their axial and bending stiffnesses along with their respective orientations, which in turn stiffens the unit cell overall.The mechanical responses of a unit cell of the flint arrowhead geometry is examined with elasto-plastic material properties of Nylon adapted from an experimental study conducted by Villette et al.  on similshown in  are examectively . The upprl = ru. rl = 0.5ru shows the best post-buckling response out of the four cases. Although the analytical model presented earlier guided how the cell deforms in terms of snap-through buckling, the fidelity of the FE models provides more detailed practical information for how the deformed cells are further affected by local material damage.Although increasing the radii of the lower members and middle strut can increase its load-carrying capacity, overly stiffening these members can have an adverse effect for the post-buckling response, as shown in . 3.5a shows the normalized load P/PC versus normalized axial end-shortening Δ/nH of four flint arrowhead stacks, those with relative lower member radii rl/ru being 40%, 45%, 50% and 70%.Similar to the unit cell study, the behaviour of several flint arrowhead stacks are examined presently. The lower member and middle strut radii are varied to establish the influence that these parameters have on the overall mechanical response and, by implication, on the energy absorption and structural isolation characteristics. Figure 10rl/ru = 0.4 shows a reduced stiffness in comparison with the remainder. However, in general, these initial differences which, as established from the unit cell model, are governed by the stiffness of the middle strut(s), are small. By contrast, significant differences are observed in the post-buckling response. For cases with smaller lower member radii, such as the case with rl = 0.4ru, a re-stiffening response as well as an earlier onset of densification is observed. This is predominantly owing to the reduced stiffness of the lower members allowing an easier geometrical phase transition and subsequent cell densification. As the lower members are thickened, as in the cases where rl/ru are 0.45 and 0.5, there is more resistance to the transition, leading to greater plateauing whose paths are more uniform in terms of load, which are ideal responses for structural isolation. Indeed, there appears to be a threshold for this desired outcome, which in this case is when the lower members and the middle struts are set to approximately 0.45ru. For this case, shown by the solid line curve in figure 10a, there are minimal disruptions in the post-buckling range as the cells sequentially buckle and there is a significant extent of the desired quasi-zero stiffness prior to densification. However, as the lower members are thickened further, the mechanical response exhibits less smooth behaviour with disruptive localized deformation patterns in the case where rl/ru = 0.5. For the stiffest case (rl/ru = 0.7), the cells effectively begin to act independently of each other; an initially negative stiffness is exhibited as an individual cell buckles that subsequently densifies in a similar way to the cases presented in figure 3a, particularly where the middle strut lateral spring stiffness , the panel has been geometrically graded such that the middle struts in the central region of the lattice have a reduced radius. The responses of the unit cell and stack are practically identical, both with the desired high initial stiffnesses and near-zero post-buckling stiffnesses. The panels have similar characteristics, with the main difference being the more gradual transition from the initial stiffness to the more plateauing post-buckling response. In fact, in the FP case, there is an initial plateauing beyond the critical buckling point, which is attributed to the softening of the lattice as the middle struts initially buckle, and then a small re-stiffening path before the largely plateauing response as successive cells gradually transition between the conventional to auxetic phases. The post-buckling response also shows regions with disturbed and undulating paths caused by the reduced stiffness of the overall lattice as hints of global, Euler-type, buckling appear to be triggered. However, these minimal disturbances in the post-buckling path are eliminated through geometrical grading in the FP* panel, as well as the reduction in the large oscillations observed at high Δ/nH values as the densification phase takes hold.An entire lattice of the flint arrowhead geometry is sandwiched between the two end-plates as a core component of a panel and is analysed. Figure 10. 4a, were fabricated using the industrial three-dimensional printer Formiga P 110 Velocis [−3, both values that are taken from the manufacturer’s data sheet [To validate the FE model, a series of unit cell and lattice prototypes were designed and produced through additive manufacturing for physical testing. The three-dimensional design of both the unit cell and panels was conducted within the commercial parametric design software Rhinoceros 3D  (Rhino) figure 11 Velocis . This thta sheet .Figure P versus normalized axial end-shortening Δ/H response for the flint arrowhead unit cell case comparing the experiment with the FE model. The displaced unit cell from the experiment is shown in H < 0.1. The general response, in both cases, can be subdivided into the familiar three stages: the pre-buckling axial compression stage shown by the initially steep linear part of the response; followed by the post-buckling path with an initial sharp drop in stiffness that then reduces further, and lastly the densification phase where the stiffness resumes increasing. Beyond the range where Δ/H > 0.1 the experimental result begins to diverge from the more plateauing response observed in the FE model, as supported by the corresponding test photographs in Physical tests were conducted on a flint arrowhead unit cell as well as on a panel with a lattice core comprising the flint arrowhead geometry, to verify the responses of the numerical results. H = 0.1. It is also worth noting that only the middle strut has buckled at this stage with minimal bending observed in the other members. As the geometry transitions to an auxetic phase , the unit cell begins to contract laterally. This response eventually leads to a secondary rise in the load because the lower members are under tension while the thicker upper members begin to bend, shown by the curved upper members in the deformations marked by the brown circle, where Δ/H = 0.3.According to the deformations presented in rm), in an identical fashion to the FE case FP*  stiffness phase that inhibits stress propagation while, theoretically at least, remaining elastic. In combination, this leads to excellent energy absorption and structural isolation characteristics that can shield a vulnerable structure that needs protection from the applied load. At the unit cell level, inclusion of a middle strut showed significant advantages for increasing the buckling load while the joint rotational springs, largely responsible for the intricacies of the snap-through response, dictated the overall post-buckling stiffness. The increased load-carrying capacity enhances the case for using such cellular structures since much greater quantities of energy can be absorbed during the buckling of each cell. Moreover, the advantage of being able to predict and tune the post-buckling stiffness by adjusting the various spring stiffnesses provides the potential for optimizing the lattice structure for different loading cases.The findings from the FE study essentially concurred with those from the analytical model for the unit cell, where similar stiffness variations were initiated through changes to member radii, which affects both the axial and bending stiffness of the individual members of the cell structure. The middle strut radius was modified to change the initial stiffness as well as the intrinsic load-carrying capacity of the cell and, in this instance, the radii of the lower members were also modified to tune the snap-through buckling response. The most desired response with the presently selected materials and arrangement was shown to occur when the lower members and middle strut radii were set to 50% of the upper member radii. Increasing the stiffness beyond this threshold led to a distinctly unstable post-buckling response with a loss in load-carrying capacity and the potential to damage the material prematurely.The analytical model was also enhanced to join several flint arrowhead cells together as a stack. Under loading, it was shown to produce a desirable sequential buckling response, the benefits of which are that it can extend the desirable quasi-zero stiffness response range. This potentially allows the lattice to absorb much more energy while protecting the aforementioned vulnerable structure and effectively makes the system scalable with the energy absorbency being related to the number of cells that buckle sequentially within the stack. The more physically realistic FE models of the flint arrowhead stack were then used to investigate methods of tuning the post-buckling response. Similar to the corresponding unit cell study, for the selected materials and arrangement, the lower members and middle struts were found to work best when their radii lay within the range 45–50% of the upper member radii. Below this range, a re-stiffening post-buckling response was observed that violated the quasi-zero stiffness requirement and anything above the specified range showed much more unstable oscillations in the mechanical response. These oscillations were attributed to local cells densifying before triggering instability in adjacent cells, both of which are not ideal particularly for structural isolation applications. The desired response achieved through these parametric choices were also scalable since largely similar responses were observed for full panels with flint arrowhead lattice cores. The post-buckling response could also be further tuned through modifications to middle strut radii at particular locations throughout the span of the stack. Finally, experimental tests were conducted both on a unit cell and a lattice panel, both of which were in very good agreement with the FE model. The pre- and post-buckling paths for both cases matched, with slight discrepancies only emerging from the experimental set-up or imperfections in the three-dimensional-printed specimens. The experimental work not only verifies the numerical models but highlights the practicality of the work where a system may be developed further for use in practice. Moreover, since the majority of the responses observed currently are within the elastic range, these promising results open up the scope for further work that could examine full recoverability of such lattices that may be called into service in quick succession. Moreover, protection systems that are presently single-use may be able to be sensibly repaired and hence re-used with the advantages that has in terms of resource use and sustainability.. 6The nonlinear mechanical behaviour of a mechanical metamaterial composed from a cellular flint arrowhead geometry was examined through a bottom-up approach of initially investigating the response at a unit cell level and later within a stack of cells and then an entire lattice core. Theoretical, numerical and experimental methodologies were used to understand the controlling mechanisms. The effects of varying different stiffnesses by adjusting geometric properties and arrangements were used to tune the mechanical response to give the desired response for enhanced energy absorbency and structural isolation. The present work provides an analytical framework for engineering and potentially optimizing such lattices so that elastic buckling may  replace material damage as the principal mechanism for absorbing energy while protecting a vulnerable structure and remaining undamaged. This potentially opens up the opportunity to devise a repairable and sustainable protection system that has the advantages of not being single-use and hence not requiring immediate replacement once mobilized into service. This could, in turn, reduce whole-life costs while increasing structural resilience such that critical infrastructure is not left unprotected whereas current practice would necessitate replacement of the protective system.


The library will endure; it is the universe. As for us, everything has not been written; we are not turning into phantoms. We walk the corridors, searching the shelves and rearranging them, looking for lines of meaning amid leagues of cacophony and incoherence, reading the history of the past and our future, collecting our thoughts and collecting the thoughts of others, and every so often glimpsing mirrors, in which we may recognize creatures of the information.The Library of BabelJorge Luis Borges (1899—1986)Nearly 10 years ago, the Journal of Experimental Orthopaedics was launched by the European Society of Sports Traumatology, Knee Surgery & Arthroscopy (ESSKA). The vision behind its establishment was to create an open access journal that complemented the esteemed Knee Surgery, Sports Traumatology, Arthroscopy (KSSTA) journal with a journal focusing on basic orthopaedic research while maintaining a strong surgical background . The strAlready in the past 10 years since its launch, the Journal of Experimental Orthopaedics has influenced the trajectory and shape of the global landscape of orthopaedic research. Since the publication of its first article, 638 articles have been published, attesting to its impact. Part of this success is that the Journal has been supported and enriched by highly commendable initiatives of the many committees and groups within and outside of ESSKA. Good examples are the work of the ESSKA Basic Science Committee on tendinopathy , the ESSThe vast range of themes covered ranges from basic science topics like aggrecan, the major proteoglycan in the articular cartilage , biomateVERITAS”, the truth, remains the ultimate goal of all science conducted and published.What lies ahead? Artificial intelligence is a potentially powerful tool but likewise a debated topic in the academic and publishing community . In his I am convinced that the Journal of Experimental Orthopaedics will continue to represent a trustworthy and indispensable resource for our community of orthopaedic researchers and clinicians, providing a basis for the high-quality care of the patients that we wish to serve with our work.Sincerely,Henning MadryFounding Editor-in-ChiefJournal of Experimental Orthopaedics


Magnetic anastomosis substantially shortens the duration of vascular anastomosis. We aimed to apply magnetic anastomosis technology (MAT) to donor liver implantations in pig orthotopic liver transplantation (OLT). Twenty healthy adult pigs were randomly divided into donors and recipients, and major vascular anastomosis was performed using MAT during OLT. Recipient liver and kidney function was measured pre-surgery and 12, 24 and 72 h post-surgery. Vascular anastomoses examinations were performed using ultrasound or angiography weekly post-surgery, and pathological examinations of vascular anastomoses were performed during autopsy after animal euthanasia. All recipients survived 24 h after surgery, which is considered as successful transplantation. Anhepatic duration was only 13 min, and no anastomotic obstruction or stenosis, magnetic displacement and anastomotic angulation, or distortion was found upon postoperative examinations of major liver vasculature. Aspartate aminotransferase, alanine aminotransferase, and total bilirubin serum levels increased considerably postoperatively. The follow-up period for this study was 1 year, and the median survival time of all recipients was 115 d (interquartile range = 11–180 d). The main causes of death were liver failure, immune rejection, infection, and arterial anastomotic bleeding. Moreover, vascular anastomoses healed well with a survival time of more than two weeks. We developed a novel magnetic device to create a fast and safe technique to perform major vascular anastomoses in pig liver transplantations. Additionally, the liver graft implantation using MAT considerably shortened the recipient warm ischemia time, which will reduce the extent of ischemia–reperfusion injury. We conclude that MAT is an effective method for donor liver fast implantation in OLT in pigs. A long anhepatic period is accompanied with long warm ischemia time in donor organs and long blood flow disturbance time in recipient organs, which may increase the risk of allograft dysfunction, intestinal bacterial translocation, acute liver failure, and renal insufficiency.Liver transplantation is an effective method for the treatment of end-stage liver diseases, and the anhepatic phase duration is related to the short- and long-term prognosis of recipients5. Previously, MAT has been applied to liver implantation in animal models7. Based on previous research, we developed a novel magnetic device to facilitate a fast and safe technique to perform major vascular anastomoses in pig liver transplantations.To the best of our knowledge, the simplest and only readily available option to shorten the anhepatic period is rapid graft revascularization, also called donor liver fast implantation. However, this procedure normally requires a traditional hand-sewn vascular anastomosis. In contrast, magnetic anastomosis technology (MAT) is a convenient and time-saving method for revascularizationThe liver transplantation using MAT was successful in all recipient pigs. The median operation time was 225 min (interquartile range [IQR] = 198–375 min), and the median cold ischemia time of donor livers was 59 min (IQR = 40–84 min). Notably, the mean anhepatic duration was only 13 min (IQR = 9–20 min). During the anhepatic phase, the median suprahepatic, infrahepatic inferior vena cava, and portal vein anastomoses times were 4 min (IQR = 3–7), 3 (IQR = 2–5) min, and 3 min (IQR = 2–6) respectively. Additionally, the median recipient warm ischemia time, defined as the time from when the liver graft is taken out of the cold preservative solution to reperfusion, was 4 min (IQR = 3–7 min). However, the hepatic artery and biliary anastomosis using a manual suturing technique seemed time consuming: 17 (IQR = 13–23) min in the hepatic artery anastomosis, and 15 (IQR = 11–20) min in the biliary anastomosis.p < 0.05; ALT: pre-surgery 76(IQR = 59–109) U/L, 12 h postoperatively 1463(IQR = 1319–1551) U/L, 24 h postoperatively 1294(IQR = 1128–1390) U/L, and 72 h postoperatively 712(IQR = 622–784) U/L, p < 0.05, Fig. p < 0.05, Fig. p < 0.05; CRE: pre-surgery 73(IQR = 66–86) μmol/L, 12 h postoperatively 80(IQR = 65–86) μmol/L, 24 h postoperatively 70(IQR = 63–80) μmol/L, and 72 h postoperatively 73(IQR = 65–81) μmol/L, p < 0.05, Fig. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels significantly increased 12 h after operation and then decreased at 24 h postoperatively (AST: pre-surgery 82(IQR = 76–106) U/L, 12 h postoperatively 1538(IQR = 1478–1673) U/L, 24 h postoperatively 1338(IQR = 1193–1596) U/L, and 72 h postoperatively 470(IQR = 309–585) U/L, The median survival time of recipients after transplantation was 115 (IQR = 11–180) d. The main causes of death in recipients were liver failure , immune rejection n = 3, 25.0%), and infection . Other causes of death included pulmonary edema  and hepatic artery anastomotic bleeding . Additionally, one recipient died of unknown causes. No obstructions or leaks in the inferior vena cava or portal vein inflow were found in recipients immediately after the surgery. No anastomotic obstructions or stenosis, magnetic displacements, or anastomotic angulation or distortion were detected in recipients after transplantation  in previous studies are not suitable as permanent implants in organisms. Based on this, we designed this magnetic vascular anastomosis device assembled by a pair of matching Ti-NdFeB composite rings that can be permanently retained in the body. These magnetic anastomosis rings had been successfully applied in end-to-end portal vein anastomosis in previous research and demonstrated good biocompatibility, along with simplifying vascular anastomosis simplified and saving time12.The hand-sewn procedure is still the primary method of vascular anastomosis during liver implantation in clinical liver transplantation, which leads to a longer anhepatic period (40–80 min) because of its complexity and time-consumption13. In this study, magnetic anastomosis rings were successfully employed in liver implantation, which significantly shortened the anhepatic time . When using MAT, at least a 2-cm vessel stump is required to install the anastomotic ring. Thus, it is essential to dissociate a vascular vessel of sufficient length before the anhepatic phase. In OLT, three major vessels need reconstruction during the anhepatic phase. Unlike that for the portal vein and infrahepatic vena cava, the process of dissociating the suprahepatic vena cava requires some ingenuity due to its special anatomical location. Thus, the phrenic vein was ligated during the process of dissociating the suprahepatic vena cava in this study. However, no diaphragm dysfunction was detected after operation in any recipients.Compared to classical orthotopic liver transplantation, the piggyback procedure resulted in a 50% decrease in the duration of the anhepatic phase, but still requires at least 30 min14. Thus, a short anhepatic period may reduce the kidney and intestine damage. In this study, there were no substantial differences in serum BUN or CRE levels before or after the anhepatic phase, implying that the shorter the anhepatic period, the more minor the renal function injury. Additionally, the recipient warm ischemia time, essentially equivalent to the “liver transplant implantation time”, was once considered “fixed time”. Essentially, traditional liver graft implantation technology seems to have no improvement given that modern liver transplant surgical techniques are already generally well sophisticated. However, previous studies indicated that short recipient warm ischemia time might improve short and long-term outcomes after liver transplantation17. In this study, the liver graft implantation using MAT considerably shortened the recipient warm ischemia time, which will in turn reduce the extent of ischemia–reperfusion injury.The inferior vena cava and portal blood flow were blocked during the anhepatic phase of orthotopic liver transplantation, and the intestinal and renal function of the recipient may be impaired due to blood circulation disorders, especially in cases where collateral circulation has not been established, such as in recipients with acute liver failureAnother issue to consider is the anastomotic angulation or distortion due to mutual magnet attraction and its biocompatibility. The distance between the portal vein anastomosis and inferior hepatic vena cava anastomosis is very short, which may lead to anastomotic angulation or distortion caused by mutual attraction between magnetic devices. However, no anastomotic angulation or distortion was found during postoperative imaging examination in this study. One possible reason for this is that the magnetic force substantially decreases with the increase in distance between the magnets, even when distance increase is small. Another possible reason is that the magnetic ring is wrapped in a magnetic shielding shell, which will prevent mutual attraction between magnets. In this study, each ring contains two parts: the biomedical titanium alloy case and the magnetic core of the NdFeB magnet ring; the titanium is biocompatible and safe. Additionally, no tissue rejection was detected in the histological examination.There were several limitations in this study. First, this study established the feasibility for magnetic vascular anastomosis in pig liver transplantation; however additional experiments with long-term follow-up are required to further evaluate and verify our findings before human clinical trials can commence. Second, as previous studies have found that magnetic fields may affect cell proliferation, differentiation, and migration, the magnetic field produced by the magnetic devices in this study may have affected the healing of vascular anastomosis and local hemodynamics. Unfortunately, we did not investigate the issue in this study, and further research is warranted.We found that MAT is safe and reliable in the rapid implantation of donor livers in pig liver transplantations. AST, ALT, and TBIL serum levels considerably increased post-surgery. The main causes of death were liver failure, immune rejection, infection, and arterial anastomotic bleeding, with median survival time of 115 days. Additionally, the liver graft implantation using MAT considerably shortened the recipient warm ischemia time, which will help reduce the extent of ischemia–reperfusion injury. Therefore, MAT is an effective method for donor liver fast implantation in OLT in pigs.5, and it is composed of a pair of magnetic composite rings. Each magnetic ring has two shapes: circular and ellipse. The circular magnetic rings with inner diameter, outer diameter, and thickness range of 10–18 mm, 20–28 mm, and 5–6 mm, respectively, were used for portal vein anastomosis , provided by the Experimental Animal Center of Xi'an Jiaotong University, were housed in a pig stable and fed a corn-soybean meal–based diet, and were randomly selected as donors or recipients. This study was approved by the Experimental Animal Management Committee of the Medical Department of Xi'an Jiaotong University (2021-595). All experiments complied with the ARRIVE guidelines and were performed in accordance with the National Institutes of Health guide for the care and use of laboratory animals .Donor and recipient surgeries were performed simultaneously in a shared operating room. The pigs were weighed and then anesthetized using an intravenous injection of 3% pentobarbital sodium solution (1 mL/kg). Implantations were completed within 1 h after donor livers were isolated. Total operation, cold ischemia, vascular anastomosis, biliary anastomosis, anhepatic, postoperative survival times, along with cause of death were recorded.The pigs were euthanized by excessive hemorrhage under full anesthesia after adequate mobilization of the liver. The donor livers were cold flushed with University of Wisconsin (UW) solution, harvested, and then preserved by simple cold storage in UW solution at 4 °C. Next, the portal vein stump was slipped through the internal hole of the magnetic ring and everted onto the pins with equal tension around the circumference. The same operation was performed to the stump of the suprahepatic and infrahepatic inferior vena cava Fig. a, b.FiguRecipient abdomens were incised through a J-Shaped Incision, and the blood vessels of the liver were fully free by 3 cm. Unlike the traditional liver implantation technique, first in this procedure, the phrenic vein had to be ligated and disconnected to the fully free suprahepatic inferior vena cava by 3 cm Fig. c–e. ThenAn intravenous drip of 3 mg/kg Cefoperazone Sulbactam Sodium  was administered daily for three days after the liver transplantation. Intravenous fluids were administered for one day, after which oral hydration was permitted. The animals also received intravenous injections of 1.0 mg/kg flurbiprofen axetil  to relieve pain, but no immunosuppressants were administered.An abdominal vascular ultrasound was performed to evaluate the patency of vascular anastomotic stoma immediately, one week, and four weeks after surgery. Transfemoral venography was also employed as an alternative if vascular ultrasound failed Fig. .Liver and kidney function tests, including AST, ALT, TBIL, BUN, and CRE levels, were performed 1 h before surgery, and 24 h and 72 h after surgery.The venous tissues, including the anastomotic site, were sampled for histopathological analysis after the animals were euthanized. All samples were fixed in 10% neutral buffered formalin. Longitudinal paraffin sections were cut at a 5-μm thickness and stained with hematoxylin and eosin. Masson’s trichrome staining was used to differentiate the connective tissue components.t-test or Wilcoxon signed rank test where applicable. p < 0.05 was considered statistically significant.Data are presented as n (%) or median (IQR). Differences between means were assessed using the paired


Enzymatic hydrolysis of starch granules forms the fundamental basis of how nature degrades starch in plant cells, how starch is utilized as an energy resource in foods, and develops efficient, low-cost saccharification of starch, such as bioethanol and sweeteners. However, most investigations on starch hydrolysis have focused on its rates of degradation, either in its gelatinized or soluble state. These systems are inherently more well-defined, and kinetic parameters can be readily derived for different hydrolytic enzymes and starch molecular structures. Conversely, hydrolysis is notably slower for solid substrates, such as starch granules, and the kinetics are more complex. The main problems include that the surface of the substrate is multifaceted, its chemical and physical properties are ill-defined, and it also continuously changes as the hydrolysis proceeds. Hence, methods need to be developed for analyzing such heterogeneous catalytic systems. Most data on starch granule degradation are obtained on a long-term enzyme-action basis from which initial rates cannot be derived. In this review, we discuss these various aspects and future possibilities for developing experimental procedures to describe and understand interfacial enzyme hydrolysis of native starch granules more accurately. The staggering interest and developments in areas such as green chemistry, food digestion related to health impacts and recyclable materials have stimulated research into enzymatic hydrolysis of insoluble biopolymers, such as starch and lignocellulose. Enzymatic hydrolysis of native starch in a heterogeneous environment of solid interfaces is a reality in many biological and industrial processes, such as transitory starch degradation in plants , dietaryStarch is commonly found in the form of granules ranging from 1 to 100 μm in size within leaves and non-photosynthetic tissues. The latter is typically considered storage starch, which is a vital source of nutrition for human consumption and is widely used in various industrial applications. The functional properties of storage starch vary significantly depending on its complex multi-level structure . HydrolyEnzyme kinetics provides the experimental link between structure and function in biocatalysis. Contrary to homogeneous catalysis, where substrate and enzyme are both in solution, the hydrolysis of insoluble solid substrates  constitutes a heterogeneous  catalytic process that is challenging because the molar concentration of the substrate cannot be defined unambiguously . Classichttps://www.reportlinker.com/p05485911/Global-Starch-Industry.html?utm_source=GNW, accessed on 20 December 2022).The starch granule is an exceptionally well-organized and compact polysaccharide energy source . It formThe starch granule is a semi-crystalline multi-level entity with specific structural features, defined at the molecular level mainly by the essentially linear α-1,4 glucan amylose (AM) and the branched α-1,4;α-1,6 glucan amylopectin (AP) , at the Models and representations of these different structural levels are continuously discussed . One imh-type polymorph, made of single helices, typically complexed with lipids . A . A 75]. Irrespective of which structural representations that are applied as models for starch granules, e.g., the blocklet and the backbone models, the double-helical chain arrangement forms the foundation of the crystallinity, and despite their tight packing, both these and the amorphous parts of the granule are targets for amylolytic cleavage. However, the number of binding sites available in double-helical structures is limited due to the densely-packed crystalline matrix providing protection for glucosidic linkages from access by enzymes . This efThe flexibility of the protruding chains on the surface of starch granules and their chain length are considered crucial factors determining the susceptibility of starch to amylolysis . As showkobs) values are 22 × 10−3 for pea mutant starch and 2.0 × 10−3 s−1 for potato) [It has been suggested that the hydrolysis of starch granules is primarily dictated by the supramolecular structural  characteristics of the granule rather than internal features such as AC and relative crystallinity . These s potato) . Moreove potato) . Hence,  potato) , as well potato) . Howeverk, min−1) 2- to 3-fold) [An additional layer of complexity is added by taking into account the proteins associated with starch granules, as these can prevent amylolytic attack. Thus, the removal of such bound protein  enhances the in vitro digestibility of starch (the hydrolysis rate coefficient ( 3-fold) ,157,158, 3-fold) . In conct is the digestion time (min), tC is the fraction of digested starch at digestion time t, and k is the digestion rate constant (min−1). The value of k can be obtained from a logarithm of the slope (LOS) plot to avoid using the imprecise value of maximum digestion extent, C∞ (Equation (2)) [Several attempts have been made to quantify reaction rates of granular starch digestion, especially for α-amylase ,160,161.ion (2)) .(2)In(dk) and maximum digestion extent (C∞) (Equation (1)).This LOS analysis has been shown to provide reliable linear fits to digestion data obtained from a range of different starch types . The prik value) than large granules. Compared with the densities of crystalline and amorphous lamellar regions, the presence of granular pores and channels and length of amylopectin “spacers arms” (the link between the double-helices and the amorphous “backbone” of clusters) and branches are more likely to affect enzymatic susceptibility [2), while small pores (0.05–0.3 μm2) limit granule hydrolysis [k and C∞ value) rather than the molecular and crystalline structure [The dimensions of native starch granules are critical with respect to controlling digestion by α-amylase. In general, small starch granules are degraded faster  [MK is relatively large since only a few of all α-1,4-linkages present in the total starch chains are available for amylase binding and subsequent reaction. Hydrothermal treatment increases the amount of highly accessible starch (gelatinized) and causes MK to decrease significantly [M-M kinetics provides a relationship between initial, linear reaction rates and substrate concentration. The fundamental form of the M-M kinetics is as follows:ydrolase . Vmax isncy (CE) . For natficantly .MK, kcat and CE = kcat/MK) and starch granule characteristics, including surface area and gelatinization enthalpies [MK values [Several studies have demonstrated that the application of the M-M kinetic model is useful for studying starch granule amylolysis in vitro. Several relationships have been established between the kinetic parameters  in the intestinal villus can have relevance to granular starch digestion in vivo . These es bromii , and recescentis . The effescentis , the infescentis . HoweverSince the reaction between digestive enzymes and the starch granule occurs in a two-phase system, the reaction mechanism involves a kinetically-significant adsorption step as well as the actual catalysis, as discussed above. It has been suggested that hydrolysis resistance in starch has two fundamental origins: binding-limiting, where binding to the enzyme is the limiting factor; or hydrolysis-limiting after binding, where the hydrolysis step itself is limiting after binding has occurred. Therefore, it is important to determine which limitation, or combination, is responsible for resistance in a particular starch or food .Bright-field and fluorescence microscopy have enabled the observation of the binding of active and inhibited hydrolases to starch granules, revealing several important findings: (1) the surface structure and botanical origin of the starch granules affect amylase binding, with maize starch granules showing more enzyme binding than potato starch granules; (2) the surface of starch granules is heterogeneous as an effect of digestion, with certain regions being more susceptible to enzymic degradation ; and (3)kinΓmax (in the unit mol/g) which enumerates sites available for enzyme attack per gram of substrate (Equation (6)). This approach requires experiments that include both enzyme and substrate saturation . When combined with Langmuir isotherm data for enzyme adsorption to the surface of starch granules, it is possible to calculate the density of attack and binding sites in relation to different surface structures. Such data can provide important insights into the mechanisms of amylolytic reactions for a range of starch substrates, especially related to whether the reaction is limited by binding or catalysis [K½ is the mass load at substrate half-saturation given by the conventional M-M, and MK is the molar concentration of attack sites that gives enzyme half-saturation given by the inverse M-M.In classical M-M enzyme kinetics, measuring catalysis for two freely diffusible enzymes and substrate species provides an important experimental link between starch structure and hydrolysis efficiency. However, as already mentioned, it is unclear whether conventional M-M theory, which requires a large excess of substrate, is biologically fully relevant for interfacial starch amylolysis. It was recently demonstrated that using microcrystalline cellulose from wood as the model solid substrate for cellulolytic enzymes, simple steady-state kinetics can be applied to heterogeneous substrate systems  by varyiatalysis ,72. MoreNotably, the relationship between the rate of glucosidic bond hydrolysis and enzyme concentration is not exactly linear for a granular starch system since not all the enzyme was able to bind to the surface, and not all the binding events are productive, as discussed above. Such effects are important to quantify and need to be addressed. For cellulases, it has been shown that not all binding sites are competent for catalytic conversion , and henInterfacial enzyme reactions are natural for starch granules, but our understanding of the kinetics remains far less developed than for enzyme reactions in solution. From a nutritional perspective, native starch is an important source of RS, which is physiologically useful for reducing risk factors such as obesity and type 2 diabetes . HoweverAn in vitro digestion approach provides an efficient key experimental link between the starch structure and nutritional function in vivo. Instead of only comparing experimental data of starch digestion, the digestion curves can be modeled by kinetic equations (first-order kinetics and M-M kinetics and their derivations ). Such k


Tendon stiffness and elastic energy were measured during ramp and ballistic contractions. Active muscle stiffness was significantly correlated with joint stiffness, except for a few conditions. Tendon stiffness measured during ramp and ballistic contractions was not significantly correlated with joint stiffness. The ratios of electromyographic activity before landing and during the eccentric phase to that during the concentric phase were significantly correlated with joint stiffness. In addition, jumping heights at 10 and 20 cm (except for 30 cm) drop heights were strongly associated with the tendon elastic energy, whereas no other measured variables showed significant correlations with jumping heights. These results suggested that (1) joint stiffness is determined by active muscle stiffness and electromyographic activity patterns during jumping, and (2) jumping height is determined by tendon elastic energy.The present study aimed to examine the effects of muscle‐tendon mechanical properties and electromyographic activity on joint stiffness and jumping height and to explore the determinants of joint stiffness and jumping height. Twenty‐nine males performed unilateral drop jumps at three drop heights  using only the ankle joint on the sledge apparatus. Ankle joint stiffness, jumping height, and electromyographic activity of the plantar flexor muscles were measured during drop jumps. Active muscle stiffness of the medial gastrocnemius muscle was calculated according to changes in the estimated muscle force and fascicle length during fast stretching at five different angular velocities (100, 200, 300, 500, and 600 deg s o date, there is no unanimous view on the determinants of joint stiffness and jumping height. The present results suggest that joint stiffness is determined by active muscle stiffness and electromyographic activity patterns, while jumping height is determined by tendon elastic energy. These findings will contribute to the establishment of training methods to improve stretch‐shortening cycle performance. On the basis of an α level of 0.05 and a power (1 − ß) of 0.8, G*Power (G*Power 3.1.9.3) showed that at least 25 participants were necessary for this study. Twenty‐nine physically active men  participated in this study. They were not involved in any type of resistance exercise program for at least 1 year before testing. They were fully informed of the procedures to be utilized, as well as the purposes of the study. Written informed consent was obtained from all participants. This study was approved by the Ethics Committee for Human Experiments, Department of Life Science (Sports Sciences), The University of Tokyo.The sample size was estimated using data from our preliminary study  was used to measure active muscle stiffness using the procedure described in our previous study . The dynamometer was programmed to apply 100 to 80 deg of dorsiflexion. The measurement of active muscle stiffness was performed three times per each angular velocity at 50% MVC with the visual aid of exerted torque with an oscilloscope. During fast dorsiflexion, participants were asked to maintain the same level of effort (under consciousness) during dorsiflexion rotation. The order of tasks  was randomized to avoid any systematic effects. Periods of 140, 80, 60, 48, and 48 ms after the onset of stretch were analyzed at 100, 200, 300, 500, and 600 deg s−1 to equalize the analyzed range of motion among the five angular velocities  within the plantar flexor muscles . Ultrasonic images were stored at 100 Hz at 100, 200, and 300 deg s−1 and 125 Hz at 500 and 600 deg s−1 in the computer memory of the apparatus  was 15.7% at 100 deg s−1, 12.4% at 200 deg s−1, 12.0% at 300 deg s−1, 9.4% at 500 deg s−1, and 12.2% at 600 deg s−1.During the measurement of active muscle stiffness, the fascicle length of MG was measured using real‐time ultrasonic apparatus  at two different strain rates (see below) were measured using the procedure described in our previous studies  were synchronized using a timer. Displacement of the intersection point between the fascicle and aponeurosis indicated the lengthening of the tendon. However, the movement of this point was also caused by angular joint rotation occurring in the direction of ankle plantarflexion during “isometric” contraction. To measure ankle joint rotation during the exercises, an electrical goniometer (Penny and Giles) was placed on the lateral aspect of the ankle. Additional measurements were conducted under passive conditions from 90 to 99 deg of the ankle joint to correct the measurements taken for tendon elongation. The movement of this point under passive conditions was subtracted from the measured tendon elongation during isometric contractions . The experimental setup is shown in Figure J are the vertical component of the ground reaction force, the length from the estimated center of the ankle joint to ball of the foot, and ankle joint angle, respectively. Ankle joint stiffness was calculated as the change in joint torque divided by the change in the ankle joint angle during the eccentric phase  to become accustomed to the test procedure. They were dropped from three drop heights  from the surface of the force plate with assistance using equipment of the sledge apparatus. After landing on the force plate, they stopped the fall motion by exerting eccentrically plantar flexion torque and then immediately started plantar flexion to take off. The test was repeated five times per condition  with at least 1 min between trials. A typical example of the raw data  is presented in Figure In addition, electromyographic activity (EMG) during jumping was sampled at 1 kHz using a wireless EMG telemeter system . Surface electrodes  were placed on the skin over the muscle belly of MG, lateral gastrocnemius muscle (LG), and soleus muscle (SOL). The raw data were band‐pass filtered between 20–500 Hz. EMG amplitude was rectified and averaged for the following phases during jumping (mEMG): before landing  for one‐way ANOVA. To assess the relationships among measured parameters, Pearson's or Spearman's correlation coefficient according to data distribution was computed. The level of significance was set at p < 0.05. Statistical computations were performed using IBM SPSS Statistics (version 27).Descriptive data included means ± SD. The Kolmogorov–Smirnov test was used to verify the normal distribution of the measured variables. Joint stiffness at a 20‐cm drop height, jumping height at a 30‐cm drop height, tendon stiffness measured during ballistic contractions, and the ratios of mEMG before landing and during the eccentric phases to that during the concentric phase at all drop heights did not show a normal distribution, whereas the other measured variables showed a normal distribution. One‐way analysis of variance (ANOVA) with repeated measures was used to detect the significant effect of the drop heights  on the measured variables during the drop jump. If the F statistic of the analysis of variance was significant, differences among means were assessed using multiple comparisons with Bonferroni's correction. In ANOVA, Mauchly's sphericity test was performed to assess the homogeneity of variance. Greenhouse–Geisser correction was applied where the assumption of sphericity was violated. The effect size was calculated using partial eta‐squared  and range of motion  during the contact phase were significantly greater at higher drop heights, whereas joint stiffness was significantly lower at higher drop heights . The angular velocities during the eccentric phase were significantly greater at higher drop heights . No differences in mEMG during the eccentric  and concentric  phases or the ratios of mEMG before landing  and during the eccentric phase  to that during the concentric phase were found among the three different drop height conditions, whereas mEMG before landing was significantly greater at higher drop heights . Jumping height was significantly greater at higher drop heights .Table −1, and between joint stiffness at a 30‐cm drop height and active muscle stiffness at 100 deg s−1  were highly correlated with tendon elastic energy measured during ramp and ballistic contractions Figure . No othe4The main results of the present study were that (1) joint stiffness was associated with active muscle stiffness and electromyographic activity patterns, but not tendon stiffness, and (2) jumping height (except for 30‐cm drop height) was closely correlated with tendon elastic energy, but not the other measured variables of muscle‐tendon mechanical properties or electromyographic activity.−1 tended to be slightly lower compared with those at other angular velocities  tended to be higher than those at the 10‐ and 20‐cm drop heights, which may partially support our hypothesis.Joint stiffness was significantly correlated with active muscle stiffness, although the correlation coefficients with muscle stiffness at 100 deg ss Figure . Our pres Figure . Based oThe relationship between tendon stiffness measured during ramp contractions and joint stiffness was consistent with the results of our previous study , The University of Tokyo.


Let’s use this unique opportunity to reflect on our history and look toward our future.While the history of modern, academic General Practice/Family Medicine (GP/FM) may seem short, the development of our discipline has already reached major milestones. To name just a few: our Danish College celebrated its 50th anniversary in 2020; the World Organization of Family Doctors (WONCA) turned 50 in 2022, and this year, 2023, our Swedish College also celebrates its 50th anniversary . Our disWhat lay behind the decision our Primary Health Care pioneers made more than 40 years ago to launch a Nordic, English language, medical journal of their own? Various explanations appeared in the journal’s first issue . Here arth edition of the International Classification of Diseases (ICD-7), which then lacked classifications of most symptoms.In 1966, the doctoral degree thesis that Bent Guttorm Bentsen submitted at the University of Oslo, Norway , was rejThis rejection exposed underlying problems. There were too few General Practitioners with academic backgrounds qualifying them to serve on an evaluation committee. Consequently, those who evaluated this GP/FM research study had been enlisted from other specialties and were thus unfamiliar with the relatively new GP/FM discipline.International Classification Committee (WICC). That very same Bent Guttorm Bentsen, as well as Niels Bentzen (Denmark), were among this committee’s pioneering members. By 1975, the first International Classification of Health Problems in Primary Care (ICPC) was published, which soon became a fundamental primary healthcare research tool [Furthermore, research into symptoms had not yet been universally accepted, nor had a set of international classifications regarding Primary Care been developed. Little wonder that one of the first actions WONCA took in 1972 was to establish the WONCA rch tool .During the 1970s, as Nordic countries began shaping the GP/FM academic departments and institutions as well as initiating educational reforms. The collaboration of Nordic General Practitioners became a solid platform.Nordic Congresses of General Practice – in 1979 in Copenhagen, and in 198E1 in Bergen. At that juncture, our leaders became convinced that a journal of our own was warranted and would be viable. The very next year, 1982, The Scandinavian Journal of Primary Health Care was founded [The impressive range Eof research activities that were already in progress among our Nordic colleagues became clear during our first two  founded .Our journal has been in constant development during the past decades. Here are just two of the many examples of our evolution:Nordic Federation of General Practice [Initially, the ownership and organizational framework of the journal was loosely structured. In 1996, however, a crisis arose regarding collective journal subscriptions. This helped to prompt the 1999 establishment of a formal, Nordic corporate journal structure. Then, in 2005, ownership of the journal was transferred to the newly established Practice ,8.The second example is the even more consequential shift that began in 2007: our transformation from a paper-based publication into a web-based, open-access journal. This has enabled us to impact Family Practice worldwide.The last decade has seen our digital journal become firmly established under the leadership of our Editor-in-Chief, Helena Liira, and her editorial staff. According to the parameters of a frequently utilized quality indicator, the journal´s ‘Impact Factor’ (IF) has achieved the current, impressive “3.1” rating.Other transitions have begun during the last two years (2022-2023). The new contract we have with our publishers offers greater support for expansion. We are also replacing our submission management system, ‘Manuscript Manager,’ with ‘Scholar One’ software. Such shifts not only present a challengingly steep learning curve but also highlight problems. One of these is a chronic shortage of good reviewers. Medical journals everywhere are facing that issue now, and it threatens the quality of all peer-reviewed publications.The Lancet is also celebrating an anniversary now – its 200th! Their Editor-in-Chief, Richard Horton, pointed out in a recent editorial that, from its outset, The Lancet was more than a journal [ journal . It was Scandinavian Journal of Primary Health Care, too, has been more than a journal. It functions independently, with its own mission, while also being part of a bigger picture: it is one of the cornerstones of the Nordic Federation of General Practice. It shares the Federation´s ‘Vision and Mission’ as well its ‘Values, Principles and Moral Intent’ [The Lancet share common aims: we are both fighting for sustainable values [From its inception, our  Intent’ . As suche values  and gendNordic Federation, we’d like to express our sincere gratitude to Liira. She has done an extraordinary job as Editor-in-Chief. She has stood, steadfast, on the front lines, negotiating with our publishers, and scrupulously evaluating the details of our new contract.This year also brings changes to our editorial staff. Helena Liira, who followed Peter Vedsted as Editor-in-Chief in 2016, is now stepping down. On behalf of the We now welcome our incoming Editor-in-Chief, Anna Nager, and her Editorial Board. As Anna comes from Sweden, the editorial office will be moving from Helsinki to Stockholm.We look forward to continuing to create a sustainable future, with our journal reinforcing our founding ideas and core values . We rema


There is a lack of scientific understanding of adding an oyster shell powder (OSP) to geopolymer concrete. The purpose of this study is: (1) to evaluate the high-temperature resistance of the alkali-activated slag ceramic powder (CP) mixture added with OSP at different temperatures, (2) to address the lack of application of environmentally friendly building materials, and (3) to reduce solid waste of OSP pollution and protect the environment. OSP replaces granulated blast furnace slag (GBFS) and CP at 10% and 20% (based on binder), respectively. The mixture was heated to 400.0, 600.0, and 800.0 °C after curing for 180 days. The results of the experiment are summarized as follows: (1) The thermogravimetric (TG) results indicated that the OSP20 samples produced more CASH gels than the control OSP0. (2) As the temperature increased, the compressive strength and ultrasonic pulse velocity (UPV) both decreased. (3) Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results reveal that the mixture undergoes a phase transition at 800.0 °C, and compared with the control OSP0, OSP20 undergoes a different phase transition. (4) The size change and appearance image results indicate that the mixture with added OSP inhibits shrinkage, and calcium carbonate decomposes to produce off-white CaO. To sum up, adding OSP can effectively reduce the damage of high temperatures (800.0 °C) on the properties of alkali-activated binders. This is in line with the findings that have been published in the literature [3Mg(SiO4)2] crystalline phase appeared. This suggests that the addition of OSP inhibits gehlenite and akermanite growth and promotes merwinite formation. A careful study found that the calcium content of merwinite was higher than that of gehlenite and akermanite. This is because the addition of OSP provides more calcium for the phase transition to the merwinite crystalline phase. The generation of different crystalline phases is the main reason for subtle changes in the macroscopic properties.When OSP0, OSP10, and OSP20 samples were heated to 800.0 °C, the number and shape of the mixture peaks changed significantly, and new sharp peaks appeared. This indicates that some amorphous and semi-crystalline phases in the reaction products changed into crystalline phases, accompanied by the formation of new substances. The presence of new crystalline phases, gehlenite [Caterature ,40; the According to the experimental results of compressive strength, the phase transition to producing new substances is not conducive to the development of mechanical properties . However−1, while the absorption peak caused by the bending vibration of the O-H bond appears near wave number 1647 cm−1 [−1, the absorption peak of the O-C bond can be observed. With increasing OSP content, the O-C bond absorption peak’s intensity rises. The OSP’s calcium carbonate content caused this. Absorption peaks caused by asymmetric stretching vibrations of O–Si(Al) bonds in CASH gels appear in the wavenumber region of 998–937 cm−1 [The FTIR spectra of OSP0, OSP10, and OSP20 samples heated to different temperatures are reported in 647 cm−1 ,42. At a937 cm−1 ,44,45.−1 is particularly pronounced and shifts toward the lower wave number. This situation indicates that the aluminosilicate network structure in the CASH gels becomes loose.The stretching and bending vibration peaks associated with O-H bonds vanished when the exposure temperature of the mixture was raised from 20.0 °C to 400.0 °C, suggesting substantial dehydroxylation in each phase, including CASH. The weakening of the intensity of the N–O-M  bond absorption peak at 945 cmAs the exposure temperature of the mixture increased from 400.0 °C to 600.0 °C, the intensity of the O-C bond absorption peak gradually decreased, suggesting ongoing calcium carbonate decomposition. However, no significant changes were observed in the intensity of the N-O-M bond absorption peak. This shows that the temperature change at this stage had little effect on the change in the aluminosilicate network structure.Absorption peaks due to O-C bonding were detected in the OSP10 and OSP20 samples containing OSP when the mixture was exposed to 800.0 °C. This indicated that calcium carbonate was not completely decomposed after exposure to 800.0 °C. The shape, intensity, and wavenumber of the N–O–M bond absorption peaks changed significantly. This implies a significant change in the network structure of aluminum in CASH gels. Combined with the XRD analysis, a phase transition occurred at this temperature. This is the reason for the sharp decrease in the mechanical properties of the mixture .The third section investigates the macro- and micro-property results of AAM with OSP added. This section discusses the differences and similarities between the results of previous studies and ours.Most of the previous studies on the use of oyster shell powder (OSP) as a building material focused on the effect on the properties of cement concrete when used as a supplementary cementitious material instead of cement ,17. Han Our research focuses on the effect of adding OSP on the high-temperature resistance of alkali-stimulated GBFS and CP-based polymers. When the samples were exposed to 800 °C, the compressive strength increased with increasing OSP content. This indicates that after the addition of OSP, the composition of the new crystalline phase produced by the phase transformation contributes differently to the mechanical properties.This study investigated the high-temperature performance of a three-basic AAM made of recycled GBFS, CP, and OSP after curing for 180 d. The scientific innovation of this paper mainly includes the following. First, the research results of this paper provide a solution for the application of environment-friendly building materials. Second, most past studies have focused on the effect of OSP on the properties of cement concrete. The research of this paper focuses on the impact of OSP on the performance of AAM. Third, past studies have focused on room-temperature performance, while this paper investigates the high-temperature resistance of alkali-activated GBFS and CP with the addition of OSP.The TG analysis indicated that the addition of OSP to the mixture, as compared to the control OSP0, increased CASH gel production, along with the observation of a decomposition peak of calcium carbonate. This could be attributed to the participation of some calcium carbonates in OSP in the alkali activation reaction, leading to the formation of CASH gel. Furthermore, the remaining calcium carbonate decomposed at high temperatures.As the temperature increased from 20 °C to 600.0 °C, a decline in the compressive strength of the mixture was observed. This is attributed to the dehydration and partial decomposition of the CASH gel. Subsequently, a significant decrease in compressive strength was observed as the temperature increased from 600.0 °C to 800.0 °C. This can be attributed to the mixture’s phase transition and uneven shrinkage.2) of 0.90.At 20.0 °C, the addition of OSP resulted in lower UPV values for OSP10 and OSP20 compared to the control group OSP0, which did not have OSP added. This observation may be attributed to the dilution effects caused by OSP. Furthermore, a robust correlation was observed between UPV and compressive strength, with a correlation factor  appear in the mixture when the temperature increases from 600.0 °C to 800.0 °C. In addition, the morphology and position of the peaks of OSP20 were changed compared to the control OSP0. This is because, at 800.0 °C, the mixture undergoes a phase transition, and the substance produced by the phase transition also changes.Based on the FTIR analysis, the intensity of the N-O-M bond absorption peak experiences a notable reduction as the temperature rose from 20.0 °C to 400.0 °C. This suggests that the aluminosilicate network structure of CASH gel becomes less dense.The mixture’s color altered, and the shrinkage grew as the temperature rose from 600.0 °C to 800.0 °C. This is because the mixture underwent a phase transition, and the OSP20 sample containing OSP decomposed to produce off-white CaO.The scientific results of this paper mainly include the following points:In addition, in further research, more work should be conducted to clarify the influences of other substances containing calcium carbonate  on the high-temperature resistance of alkali-activated materials.