We aimed to elucidate the perioperative and short-term clinical outcomes of the Najuta thoracic stent graft system with fenestrations for supra-aortic vessels.We retrospectively investigated the perioperative and short-term clinical outcomes of 20 patients treated for arch or distal arch aneurysms using the Najuta thoracic stent graft system during the period from May 2019 to February 2023.n = 2) and type II (n = 3) endoleaks which disappeared on follow-up. The postoperative complications were stroke , paraplegia , and paraparesis . In a very old patient, a blood transfusion was performed from the common iliac artery using the retroperitoneal approach. There were no aorta-related complications such as retrograde type A dissection or distal stent graft–induced new entry.The technical success rate of the Najuta thoracic stent graft system was 95%. Of the 20 patients, 17 patients (85.0%) underwent concomitant extra-anatomical supra-aortic bypass. Postoperative CT revealed type Ia (We treated arch or distal arch thoracic aneurysms by inserting a tube-type stent graft as a scaffold on the peripheral site and placing the Najuta thoracic stent graft on the proximal site. By extending the landing zone to Zone 0 and using a low radial force, which is a feature of the Najuta thoracic stent graft system, postoperative bird-beak and aorta-related complications were avoided. The treatment of arch and distal arch aortic aneurysms using the Najuta thoracic stent graft system showed acceptable perioperative and short-term clinical outcomes. Thoracic endovascular aortic repair using the Najuta thoracic stent graft system may be a potential treatment option for arch and distal arch aortic aneurysms, warranting further studies. Thoracic endovascular aortic repair (TEVAR) has been the treatment of choice for aortic arch pathology because of the short landing zone and aortic arch curvature. However, TEVAR occasionally produces a “bird-beak” configuration and has a poor outcome , 2.Various stent graft systems have been approved for use with TEVAR. In Japan, the Najuta thoracic stent graft system  was approved for clinical use in January 2013 . This stOur experience with the Najuta thoracic stent graft system for the treatment of arch aneurysms yielded acceptable clinical outcomes. We were also able to develop a surgical method that compensates for the limitations of the Najuta thoracic stent graft system and takes advantage of its strengths for the treatment of a saccular arch aneurysm protruding toward the arch’s lesser curvature.In this study, we aimed to elucidate the perioperative and short-term clinical outcomes of the Najuta thoracic stent graft system with fenestrations for supra-aortic vessels.The study protocol was approved by the Institutional Review Board of Saiseikai Yokohamashi Tobu Hospital on January 6, 2022 . Written informed consent was obtained from each patient.We investigated 20 patients in this study consisting of 15 men and 5 women. The mean age of the patients was 79.5 ± 6.1 years . The characteristics of the patients are shown in The Najuta thoracic stent graft system is a semicustom-made fenestrated graft. The position of its fenestration can be matched to preserve the arch vessels according to the aortic arch shape for each case. The pre-shape of the stent graft can be optimized for each case by changing the connection position of each stent to approximate the three-dimensional (3D) flexion of the aortic arch.First, thin-slice computed tomography (CT) of 2 mm or less is performed, and then the Digital Imaging and Communications in Medicine (DICOM) data are sent to SB-Kawasumi Laboratories, Inc. . Second, the Najuta thoracic stent graft is prepared, and the recommended placement report is provided to the surgeon. Third, a “deployment simulation report” is created from the CT data using a 3D printer assuming that the stent graft is deployed in the aorta.The preparation of the Najuta stent graft system involves three procedures. The inclusion criteria were as follows: patients with proximal and distal neck lengths ≥20 mm and patients with proximal and distal aortic diameters ≥20 and <38 mm. Patients with an arch aneurysm involving the arch vessels, an isolated distal arch aneurysm, and acute type B aortic dissection were excluded from this study.All TEVAR patients were administered general anesthesia at our institution to ensure sufficient respiratory arrest for the precise deployment of the fenestrated stent graft. We exposed the unilateral femoral artery as the access site of the stent graft.For the “pull-through technique,” we inserted a 0.032 in × 400 cm guidewire  from the right brachial artery (BA). We caught the guidewire in the ascending aorta with a 27–45 mm snare catheter  that was inserted from the femoral artery.We performed digital subtraction angiography to ensure alignment of the peripheral fenestration marker made in the Najuta thoracic stent graft with the peripheral marker made in the left common carotid artery (LCA) or left subclavian artery (LSA). We recommend the deployment of the Najuta thoracic stent graft under self-heartbeat. For deployment, we held the Najuta thoracic stent graft rod firmly with the right hand and pulled down the outer sheath with the left hand. When the proximal two or three stents were released, the blood pressure pushed the Najuta thoracic stent graft to the periphery. We pushed back the Najuta thoracic stent graft system with the right hand, and the endoskeleton of the Najuta thoracic stent graft was fully expanded and deployed by the blood pressure. After removing the fixation thread at the tip of the Najuta thoracic stent graft, we slowly pulled out the inner sheath. The most important point when collecting the proximal tip of the Najuta thoracic stent graft system is to be careful not to let the proximal tip get into the endoskeleton of the Najuta thoracic stent graft and interfere with the fins for migrating the Najuta thoracic stent graft to the peripheral side.For aneurysms that cannot be treated with one piece of the Najuta thoracic stent graft, we usually place a second Najuta stent graft on the peripheral side. When another stent graft that is manufactured by another company is placed before the Najuta thoracic stent graft, we additionally place a fenestrated Najuta thoracic stent graft to extend the proximal neck after obtaining a certain degree of proximal neck shield with the distal stent graft. In this way, a more therapeutic effect is expected. We provided a representative procedural We followed up the patients in our outpatient clinic at 1 week, 3 months, 6 months, and 12 months after the operation and annually thereafter. The follow-up protocols consisted of physical findings, laboratory examinations, and contrast-enhanced CT.The end points included technical success, postoperative complications, aneurysm shrinkage rate, overall survival rate, freedom from reintervention rate, and freedom from aorta-related event rate.The aortic aneurysm shrinkage rate was obtained by subtracting the aneurysm diameter on a recent CT from the preoperative diameter and dividing the outcome by the preoperative aneurysm diameter. The definitions of clinical terms related to TEVAR procedures are in accordance with the reporting standards suggested by the Society for Vascular Surgery .Values were expressed as mean ± SD for continuous variables and frequencies or proportions for categorical variables. The overall survival rate and freedom from reintervention rate were obtained by the Kaplan–Meier method using SPSS Statistics v.24 .A total of 20 patients were treated by TEVAR using the Najuta thoracic stent graft system. The mean postoperative follow-up period was 22.3 ± 11.7 (4–44) months. The procedural data and postoperative data of the patients are shown in Technical success, which was defined as successful deployment in the intended position of the aortic arch, was achieved in 19 patients (95.0%). In one patient, the second stent graft caught the “fin” of the first stent graft. Thus, we discontinued the deployment of the second stent graft. The proximal landing zone was Zone 0 in all 20 patients.Regarding the concomitant procedures, 17 of the 20 patients (85.0%) underwent debranching bypass. LSA embolization was performed in 11 patients (55.0%), with additional LSA embolization in two patients because of type II endoleak 8 and 47 days after the first procedure. In this series, two patients (10.0%) with a shaggy aorta in the aortic arch suffered from stroke: one patient (5.0%) suffered from paraplegia, and the other patient (5.0%) suffered from paraparesis. One patient suffered from a pseudoaneurysm of the BA and underwent surgical repair on the puncture site. The other patients were discharged without major postoperative complications. The overall survival rate was 95.0% at 1, 12, and 24 months .Type 1a endoleak occurred in two patients (10.0%), and type II endoleak occurred in three patients (15.0%). In the patients with type Ia endoleak, meticulous follow-up was conducted, and strict blood pressure control reduced the degree of leakage. In the patients with type II endoleak from the LSA, two patients underwent LSA embolization using an Amplatzer Vascular Plug , but the other patient did not undergo additional treatment as the endoleak was not observed during the follow-up. The freedom from reintervention rates were 95.0%, 90.0%, and 90.0% at 1, 12, and 24 months, respectively .The positions of the distal end of the stent graft were at T6 (two patients: 10.0%), T7 , T8 , T9 (one patient: 5.0%), and T12 , with an average of T7.6 ± 1.3. Of the 20 patients, 11 patients (55.0%) were treated with two stent grafts, and two patients (10.0%) were treated with three stent grafts. Of these 13 patients, distal stent grafts made by other companies were used.Aortic events such as enlargement, retrograde aortic dissection (RTAD), and distal stent graft–induced new entry were not observed during the follow-up period.In this study, we set out to elucidate the perioperative and short-term clinical outcomes of the Najuta thoracic stent graft system with fenestrations for supra-aortic vessels. The use of this system with TEVAR showed no postoperative bird-beak and aorta-related complications, indicating its potential as a treatment option for arch and distal arch aortic aneurysms.Since the approval of the Najuta thoracic stent graft system for clinical use in Japan in January 2013, treatments of arch and distal arch aneurysms by TEVAR have expanded in terms of anatomical indications. For the treatment of arch aneurysms, total arch replacement is the recommended gold standard surgical procedure because of its stable long-term results. However, since the introduction of TEVAR for the treatment of thoracic aortic aneurysms or dissections, TEVAR has reduced the number of serious complications such as respiratory failure and renal dysfunction compared with the gold standard total arch replacement, as well as markedly improved postoperative quality of life and shortened hospital stay . Thus, tNevertheless, TEVAR has also some limitations for treating aortic arch aneurysms. These include the inability to secure a sufficient proximal neck length because of the positional relationship with the supra-aortic branches and the inability to obtain a good attachment between the lesser curvature and the stent graft  which hinders proper sealing. To extend the proximal neck, the debranching and chimney procedures have been developed. However, supra-aortic debranching TEVAR reportedly caused a stroke in 7% of patients (0%–25%) as the most common perioperative complication . ConcernIn the present patient series, postoperative stroke was recognized in 2 of 17 patients (11.8%) with the supra-aortic branch bypass. However, the degree and symptoms of the postoperative stroke were not permanent, and improvement was achieved by postoperative rehabilitation. We were able to extend the proximal neck length with the supra-aortic branch bypass and avoid the bird-beak phenomenon in Zone 2. This allowed the Najuta thoracic stent graft to be inserted into Zone 0. As a procedure to avoid the supra-aortic branch bypass, the chimney technique is used for reconstructing the arch vessels without debranching. However, the chimney technique presents concerns about the gutter leak and RTAD that occur from the gap between the stent grafts in Zone 0, as well as the risk of developing a stroke. Moreover, the chimney technique has the disadvantage of being a complicated procedure compared with debranching.The Najuta thoracic stent graft system is the first commercial fenestrated thoracic stent graft system developed in Japan. The procedure for using the system involves the selection of the metal skeleton that most closely resembles the individual’s aortic arch morphology from the 3DCT and pre-creates the fenestration according to the position of the branch, making it a semicustom-made method. Additionally, the unique stabilizer function of the Najuta thoracic stent graft enables its precise deployment without the need for cardiac arrest using drugs or rapid pacing . TherefoRegarding the treatment strategy for the 20 patients in our series, 11 patients (55.0%) were treated with two stent grafts, 10 of whom received the distal stent grafts made by other companies, and 2 of the 20 patients (10.0%) were treated with three stent grafts. The reason for this treatment strategy is that in cases where the proximal neck length is <20 mm, the proximal neck length is extended with the Najuta thoracic stent graft after ensuring a certain degree of proximal neck sealing by a peripherally inserted stent graft as a scaffold. This enhances the therapeutic effect. It is considered that the Najuta thoracic stent graft, which has a weaker radial force, receives blood pressure and expands in Zone 0. The bird-beak phenomenon is less likely to occur than in debranching TEVAR using a stent graft manufactured by other companies .The treatment of arch and distal arch aortic aneurysms using the Najuta thoracic stent graft system showed acceptable perioperative and short-term clinical outcomes. The insertion of a tube-type stent graft as a scaffold on the peripheral site utilizes the best features of the Najuta thoracic stent graft by extending the landing zone to Zone 0. This avoids the bird-beak phenomenon and catastrophic aortic events during the follow-up. TEVAR using the Najuta thoracic stent graft system may be a potential treatment option for arch and distal arch aortic aneurysms. Global accumulation of treatment experience and careful follow-up are mandatory to build firm evidence regarding the effectiveness of this novel and promising device.


We performed an in vitro study with two clinical strains of MSSA (MSSA2 and MSSA6) and nine vascular grafts: Dacron (Hemagard), Dacron-heparin (Intergard heparin), Dacron-silver (Intergard Silver), Dacron-silver-triclosan (Intergard Synergy), Dacron-gelatin (Gelsoft Plus), Dacron plus polytetrafluoroethylene (Fusion), polytetrafluoroethylene , Omniflow II, and bovine pericardium (XenoSure). Biofilm formation was induced in two phases: an initial 90-minute adherence phase and a 24-hour growth phase. Quantitative cultures were performed, and the results were expressed as log10 CFU per milliliter. The Dacron-silver-triclosan graft and Omniflow II were associated with the least biofilm formation by both MSSA2 and MSSA6. MSSA2 did not form a biofilm on the Dacron-silver-triclosan graft (0 CFU/mL), and the mean count on the Omniflow II graft was 3.89 CFU/mL (standard deviation [SD] 2.10). The mean count for the other grafts was 7.01 CFU/mL (SD 0.82). MSSA6 formed a biofilm on both grafts, with 2.42 CFU/mL (SD 2.44) on the Dacron-silver-triclosan graft and 3.62 CFU/mL (SD 2.21) on the Omniflow II. The mean biofilm growth on the remaining grafts was 7.33 CFU/mL (SD 0.28). The differences in biofilm formation on the Dacron-silver-triclosan and Omniflow II grafts compared to the other tested grafts were statistically significant. Our findings suggest that of the vascular grafts we studied, the Dacron-silver-triclosan and Omniflow II grafts might prevent biofilm formation by MSSA. Although further studies are needed, these grafts seem to be good candidates for clinical use in vascular surgeries at high risk of infections due to this microorganism.The aim of this study was to quantify IMPORTANCE The Dacron silver-triclosan and Omniflow II vascular grafts showed the greatest resistance to in vitro methicillin-susceptible Staphylococcus aureus biofilm formation compared to other vascular grafts. These findings could allow us to choose the most resistant to infection prosthetic graft. Vascular graft infection (VGI) is a feared complication that affects 2 to 4% of patients . It is aIntraoperative contamination is considered the most common cause of VGI , 5, espeStaphylococcus aureus, coagulase-negative staphylococci, and Enterococcus spp  biofilms on the surfaces of biosynthetic and biologic grafts used in routine vascular surgery.Conclusive evidence is lacking on which types of grafts are most susceptible to infection . The aim10 CFU/mL), as well as standard deviation (SD) values, are shown in P < 0.001).The mean MSSA2 and MSSA6 counts (logP < 0.001) on the Dacron-silver-triclosan graft and 3.89 CFU/mL (P < 0.001) on the Omniflow II graft versus 7.01 CFU/mL on the other grafts.The Dacron-silver-triclosan and Omniflow II grafts showed the least biofilm formation for both strains and were each compared with the other grafts. MSSA2 did not form biofilm on the Dacron-silver-triclosan graft (0 CFU/mL), and the mean count on the surface of the Omniflow II graft was 3.89 CFU/mL (SD 2.10). The mean growth of MSSA2 on the other seven grafts was 7.01 CFU/mL (SD 0.82). The differences in biofilm formation by MSSA2 were significant in both cases: 0 CFU/mL (P < 0.001) for the Dacron-silver-triclosan graft and 3.62 CFU/mL (P < 0.001) for the Omniflow II versus 7.33 CFU/mL on the other grafts.The mean bacterial counts for the biofilms formed by MSSA6 were 2.42 CFU/mL (SD 2.44) on the Dacron-silver-triclosan graft and 3.62 CFU/mL (SD 2.21) on the Omniflow II. The mean growth on the other seven grafts was 7.33 CFU/mL (SD 0.28). The differences in the mean counts for the other grafts were significant: 2.42 CFU/mL  values are shown in in vitro study, we studied biofilm formation by two clinical strains of MSSA on the surface of nine vascular grafts used in routine clinical practice in Spain. Overall, the grafts that were most resistant to biofilm formation were the Dacron-silver-triclosan graft and the Omniflow II. The performance of the Dacron-silver-triclosan graft was particularly notable, as the bacterial count for one of the strains was zero in all experimental replicates.In this in vitro study confirm this improved efficacy and are consistent with recent reports (–S. aureus (MRSA). Their findings were later corroborated by Berard et al. phenol]. The excellent results observed for the Dacron-silver-triclosan graft in our  reports –13. Riccreports – were thed et al. , who shoin vitro studies have reported contrasting results  formed by these microorganisms . The matBecause biofilms confer increased protection against the immune system and antibiotics, the use of antimicrobial grafts could prevent these films from forming and limit colonization .in vitro study, its findings cannot be simply extrapolated to clinical settings, since in vivo bacterial adherence is influenced by other factors, such as graft endothelialization, contact with plasma proteins, and cellular immune responses  Dacron , (ii) Dacron heparin , (iii) Dacron with silver acetate , (iv) Dacron with silver acetate and triclosan , (v) gelatin-sealed Dacron , (vi) expanded polytetrafluoroethylene (ePTFE) , (vii) ePTFE merged with Dacron , (viii) polyester with denatured sheep collagen , and (ix) bovine pericardium .The synthetic grafts were sterilized with gas at a low temperature, while the biologic grafts were prepared with 70% alcohol under sterile conditions.The grafts were attached to a loop, as a modification of the protocol developed by Chandra et al., in order to submerge the samples in the inoculum and to keep them from floating. Using a standardized method, each graft was cut into circular pieces adjusted to the diameter of a 10-μL calibrated loop . Each graft piece was attached to a loop using 3 stitches of nonabsorbable monofilament polypropylene  . The capThree replicates of each graft and MSSA strain were studied, and the experiment was performed in triplicate.in vitro study.Two clinical strains of MSSA isolated from catheter infections were used for this Quantification of biofilm formation was performed to ensure subsequent standardization. To this end, three MSSA strains  were seeded on the surface of silicone and polyvinyl chloride discs using a slightly modified version of the protocol described by Chandra et al. . The bioA slightly modified version of the protocol described by Chandra et al.  was used7 CFU/mL was prepared with PBS, pH 7.2. Next, tubes containing 6 mL of the inoculum were prepared, and the vascular graft preparations were submerged in them. The tubes were incubated for 90 min at 37°C (adherence phase). Then, the vascular graft was gently and carefully moved from the adhesion step tube to the new tube containing 6 mL of TSB, avoiding adding any drops containing unattached microorganisms. The grafts were incubated for 24 h at 37°C and 60 rpm (growth phase).The MSSA strains were grown overnight in tryptic soy broth  at 37°C and 60 rpm. After centrifuging and washing the bacterial suspension three times with sterile phosphate-buffered saline (PBS), pH 7.2 , an inoculum of 1 × 10Following the protocol of Chandra et al. , there w10 CFU per milliliter.The suture binding the graft to the loop handle was cut outside the tube on a sterile field, being careful not to transfer bacterial cells from the loop. Then, the graft was gently transferred to a sterile 12-well plate containing 1 mL of TSB using a sterile needle, avoiding adding any drops of liquid. Finally, both surfaces of the graft samples were gently scraped into the 12-well plate using the blunt edge of a no. 11 scalpel . The suspension was transferred to new tubes, vortexed for 1 min, and sonicated for 10 min at 59 MHz. The tubes were centrifuged at 3,500 rpm for 10 min at room temperature and then resuspended with 1 mL of TSB; after that, the samples were serially diluted in physiological serum, and 50 μL was plated in tryptic soy agar  for quantitative culture. Finally, the bacterial cells were quantified and expressed as logpost hoc multiple-comparison tests with Bonferroni correction.Continuous variables are reported as the mean (standard deviation [SD]). Grafts were compared using analysis of variance, and differences were examined using t test. A P value of <0.05 was considered statistically significant. The results are presented using descriptive statistics, and comparisons were made using SPSS version 26.0 (IBM Corporation).Since none of the grafts could be considered controls, we decided to compare the two grafts with the weakest biofilm formation by both strains with the rest of the grafts. Differences were compared using the


Double-row tapered roller bearings have been widely used in various equipment recently due to their compact structure and ability to withstand large loads. The dynamic stiffness is composed of contact stiffness, oil film stiffness and support stiffness, and the contact stiffness has the most significant influence on the dynamic performance of the bearing. There are few studies on the contact stiffness of double-row tapered roller bearings. Firstly, the contact mechanics calculation model of double-row tapered roller bearing under composite loads has been established. On this basis, the influence of load distribution of double-row tapered roller bearing is analyzed, and the calculation model of contact stiffness of double-row tapered roller bearing is obtained according to the relationship between overall stiffness and local stiffness of bearing. Based on the established stiffness model, the influence of different working conditions on the contact stiffness of the bearing is simulated and analyzed, and the effects of radial load, axial load, bending moment load, speed, preload, and deflection angle on the contact stiffness of double row tapered roller bearings have been revealed. Finally, by comparing the results with Adams simulation results, the error is within 8%, which verifies the validity and accuracy of the proposed model and method. The research content of this paper provides theoretical support for the design of double-row tapered roller bearings and the identification of bearing performance parameters under complex loads. Double-row tapered roller bearing is a kind of double-row roller bearing with a tapered raceway. Because of its compact structure and good bearing performance, it is widely used in railway freight cars ,2 and hiIn the study of rotor-bearing systems, the bearing is often only equivalent to a constant stiffness spring, ignoring the nonlinear variation of bearing stiffness with load and speed ,12. WithIn this paper, the contact mechanics calculation model of double-row tapered roller bearing under composite load and the calculation method of local contact stiffness of tapered bearing are offered. On this basis, the calculation model of the overall stiffness of the bearing is obtained according to the relationship between the overall stiffness and local stiffness of the bearing. Then, according to the established model, the influence of working parameters  on the radial and axial contact stiffness of double-row tapered roller bearings is analyzed. The applicability and reliability of the model are verified via finite element simulation.rF, axial outward load aF, axial preload F0, and the external bending moment load M, taking into account the centrifugal force on the roller cjF; the function is shown in Assume that the bearing as a whole is subjected to a radial outward load mojQ, mijQ and mfjQ are the roller outer raceway contact load, roller inner raceway contact load, and roller big end rib contact load, respectively; mc1jF and mc2jF is the normal force between the roller and the cage pocket; cμ and fμ is the coefficient of friction between the roller pocket and the roller rib; and djF is the fluid resistance.For a single tapered roller with asymmetric left and right sides, the stress relationship is shown in mjo-xyz, the jth roller in column m is located at mjzxo; the following equation is established for the plane force balance:In the roller local coordinate system mc1jF and mc2jF relative to the roller and inner and outer rings is very small, so the tangential friction term between the roller and the pocket in Equation (2) can be ignored in the calculation. Therefore, the external raceway contact force mojQ for the reference and contact load mijQ and mfjQ, respectively, can be expressed asThe contact load of cω and its centrifugal force cjF ismd is the pitch diameter; sm is the mass of a single roller.The revolution speed is mojQ the components in the radial and axial directions arem is the column in which the roller is located; When m = 1, ϵ = 1; When m = 2, ϵ = 2.mjM and the resultant moment can be expressed asUnder the action of external loads, the contact load of the roller will generate a resistance moment to the bearing center Z rollers, superpose the corresponding loads of the two rows of rollers, and consider the direction of action of forces and moments to obtain the balance equation for the entire double row tapered roller bearing:For the bearing as a whole, assume that each row has iδ and oδ and that the contact angles of the inner and outer raceways of tapered roller bearings are different. When calculating the total contact displacement, the displacement at the contact point of the roller outer raceway can be used as a reference to project the contact displacement of the roller inner raceway towards the normal direction of the roller outer raceway contact, as shown in Assume that the contact displacements of the roller inner raceway and the roller outer raceway are, respectively, iδ and contact displacement at roller outer raceway oδ isThe contact displacement between the roller and the inner raceway according to the geometric relationship oδ the total contact displacement in the direction isTherefore, iG and oG are the flexibility coefficient at the contact between the inner and outer raceways, which can be obtained according to Palmgren’s correction Equation (32)E is the elastic modulus of the material; μ is the material Poisson’s ratio; Subscripts 1 and 2 refer to contact bodies 1 and 2 that are in contact with each other, respectively; i(o)k is the average diameter of the roller (wD) to the diameter of the inner and outer raceways (ri(o)D) ratio; wD is the averrage diameter of the roller; and eL is the effective length of the roller.According to Hertz line contact, the relationship between the total contact displacement and the external raceway contact load isAccording to the relationship between Equations (12)–(14), it can be obtained thatrδ, axial displacement aδ, and angular displacement θ.Generally, the inner ring is assembled with the shaft by interference and is linked with the shaft, so the two inner rings of the bearing can be considered as a whole during calculation. Assume that the displacements of the inner ring relative to the outer ring under external load are, respectively, radial displacement rδ at the position angle jφ with the j radial displacement component of the roller isRadial displacement of inner ring aδ at the position angle jφ with the j axial displacement component of the roller isAxial displacement of the inner ring θ at the position angle jφ with the angular displacement of the roller and is expressed asThe inner circle produces corner cd, then angular displacement θ of the resulting radial and axial displacement components  is as followsIt is assumed that the bearing is only subjected to δ0)Obtain the displacement only when the preload is applied jQ.For the contact stiffness Equation, only the contact load is unknown, and it is necessary to obtain it. Next, calculate the contact load rδ, aδ and θ as unknowns. The solution of the nonlinear equation set can be obtained using the iterative method, and then the contact load and contact deformation at the inner and outer raceway and the baffle can be finally obtained by substituting the solution into the corresponding equation.According to the relationship between three loads and deformation, Equation (9) is a nonlinear equation set with During the iterative calculation process, it should be noted that due to the effect of centrifugal force, some rollers may not come into contact with the inner race raceway, while there is always a minimum normal contact load between the rollers and the outer race raceway, which can be obtained from Equation (3)FcδAccording to the load-deformation relationship, the deformation amount generated by the minimum normal contact load is mnjδ and minimum contact deformation Fcδ, the larger value of the two is used as the new total contact deformation amount. Set the iteration error Δ = 1 × 10−9 and calculate the deviation between the two iteration results before and after each iteration for Δrδ, Δaδ and Δθ until the maximum deviation is less than or equal to the set iteration error Δ, the iteration is completed and the result is given as an output. The specific calculation process is shown in During the iteration process, taking the total contact deformation For the contact between tapered rollers and inner and outer raceways, Luo  gave a liQj(o) is the contact load of the inner and outer raceways.The meaning of each parameter in the Equation is the same as that in Equations (13) and (14). According to the definition of contact stiffness, the normal contact stiffness between the roller and the inner and outer raceways is obtained by deriving Equation (27) as follows:j can be decomposed into stiffness components along the radial direction (r) rjK and the stiffness component along the axial direction (z) zjK.i(o)α is the contact angle of the inner (outer) raceway of the bearing.The normal stiffness of tapered roller raK and axial stiffness ma.Km is the column of the roller, m = 1, 2; jφ is the position angle of the jth roller, jφ = 2π (j − 1)/Z; and Z is the number of rollers in each row of the bearing.The radial and axial stiffness components of each roller and inner and outer raceways are accumulated in parallel for the entire bearing to obtain the radial stiffness of a single row of bearings rK and axial stiffness a.KFor double row bearings, the radial stiffness and axial stiffness of the first and second rows are added in parallel to obtain the radial stiffness of the double row bearings Taking the HH926700 tapered roller bearing as an example as shown in cω = 1200 r/min, aF = 5000 N, F0 = 100 N, M = 20 N × m) When the radial load rF is gradually increasing from 3000 N to 9000 N , first calculate the contact loads at various locations inside the double-row tapered roller bearing under each working condition. When studying the influence of radial load on the internal load distribution of bearings, maintain the rotational speed, axial load, and preload, and keep the bending moment unchanged , 81.9% (916.2 N), and 50.6% (100.7 N), respectively. The maximum contact loads at the second row of roller outer raceways, roller inner raceways, and roller inner ring ribs increased by 261.6% (1402.5 N), 401.1% (1403.7 N), and 134.8% (154.2 N), respectively. The maximum contact load at the first row of rollers is greater than that at the second row, but the change amount and amplitude of the maximum contact load are less affected by the radial load than at the second row. This is mainly because the impact of the axial load is relatively weakened when the radial load is increased during composite loading.rF when gradually increasing from 1500 N to 9000 N ; the first column radial stiffness, the first column axial stiffness, the second column radial stiffness, and the second column axial stiffness are analyzed, and the results are shown in According to As can be seen from cω = 1200 r/min, rF = 5000 N, F0 = 100 N, M = 20 N×m). When the axial load aF gradually increases from 3000 N to 9000 N , first calculate the contact loads at various locations inside the double-row tapered roller bearing under each working condition. When studying the effect of axial load on the internal load distribution of bearings, maintain the rotational speed, radial load, and preload, and keep the bending moment unchanged ; the first column radial stiffness, the first column axial stiffness, the second column radial stiffness, and the second column axial stiffness are analyzed, and the results are shown in According to As can be seen from the results in cω = 1200 r/min, rF = 8000 N, F0 = 100 N, aF = 3000 N); the bending moment M gradually increased from 40 N×m to 120 N×m . First calculate the contact loads at various locations inside the double-row tapered roller bearing under each group of operating conditions. When studying the effect of bending moment load on the internal load distribution of bearings, maintain the rotational speed, radial load, and preload, and keep the axial load unchanged . The first column radial stiffness, the first column axial stiffness, the second column radial stiffness, and the second column axial stiffness are analyzed, and the results are shown in According to From the results in M = 20 N*m, rF = 3000 N, 0F = 100 N, aF = 1500 N). For the rotational speed cω when gradually increasing from 1200 r/min to 3600 r/min , first calculate the contact loads at various locations inside the double-row tapered roller bearing under each group of operating conditions. When studying the effect of rotational speed on the internal load distribution of bearings, maintain the bending moment, radial load, and preload, and keep the axial load unchanged . The first column radial stiffness, the first column axial stiffness, the second column radial stiffness, and the second column axial stiffness are analyzed, and the results are shown in According to As can be seen from the results in M = 20 N*m, rF = 5000 N, cω = 1200 r/min, aF = 1500 N). When the preload gradually increases from 1800 N to 4200 N , first calculate the contact loads at various locations inside the double-row tapered roller bearing under each working condition. When studying the influence of preload on the internal load distribution of bearings, maintain the bending moment, radial load, and rotational speed, and keep the axial load unchanged . When the deflection angle gradually increases from −0.0001° to −0.0005° , first calculate the contact loads at various locations inside the double-row tapered roller bearing under each group of operating conditions. When studying the effect of deflection angle on the internal load distribution of bearings, the axial displacement is 0, the radial displacement is 0, and the rotational speed is constant The contact load calculation results of roller-inner raceway, roller-outer raceway and roller-rib obtained using the model and method proposed in this paper are in good agreement with the Adams simulation results, and the maximum relative error is within 8%, which can provide some guidance for engineering application.(2)Under a radial load, as the radial load increases, when the contact between the roller and the raceway increases, the second row of bearings will have a “sudden increase phenomenon”. Under an axial load, as the radial load increases and the contact between the roller and raceway decreases, the second row of bearings will experience a “sudden decrease phenomenon”. The influence of bending moment load on stiffness is very small. When the rotational speed increases, the contact between the roller and the raceway will decrease, and the second row of bearings will have a “sudden decrease phenomenon”. As the axial preload increases, the second row of rollers gradually changes from partially loaded to fully loaded, and the stiffness increases rapidly. The axial preload has the greatest impact on the bearing stiffness. As the deflection angle increases, the stiffness steadily increases, and the axial stiffness of the first and second columns is completely equal.(3)There is an optimal preload that minimizes the maximum contact load of the roller when other load conditions remain unchanged for a double-row tapered roller bearing. This effect of preload on the maximum contact load can provide guidance for applying preload in engineering applications.Aiming at the problem of contact stiffness of double-row tapered roller bearings, an equation for the contact stiffness of double-row tapered roller bearings is derived based on the calculation of load distribution. The influence of complex loads on the contact stiffness of bearings is studied through numerical calculations, and the following conclusions are obtained:Future work plan: The authors will build a double-row tapered roller bearing test platform to further verify the validity and accuracy of the method and model. Based on the work of this paper, the influence of the assembly process of bearing and rotor on the dynamic stiffness of double-row tapered roller bearing is studied.


Starch provides approximately half of humans’ food energy, and its structural features influence human health. The most important structural feature is the chain length distribution (CLD), which affects properties such as the digestibility of starch-containing foods. The rate of digestion of such foods has a strong correlation with the prevalence and treatment of diseases such as diabetes, cardiovascular disease and obesity. Starch CLDs can be divided into multiple regions of degrees of polymerization, wherein the CLD in a given region is predominantly, but not exclusively, formed by a particular set of starch biosynthesis enzymes: starch synthases, starch branching enzymes and debranching enzymes. Biosynthesis-based models have been developed relating the ratios of the various enzyme activities in each set to the CLD component produced by that set. Fitting the observed CLDs to these models yields a small number of biosynthesis-related parameters, which, taken together, describe the entire CLD. This review highlights how CLDs can be measured and how the model-based parameters obtained from fitting these distributions are related to the properties of starch-based foods significant for health, and it considers how this knowledge could be used to develop plant varieties to provide foods with improved properties. A large proportion of meals in most societies contain rice, wheat, maize, taro or potato, and thus contain high proportions of starch ,2,3,4. TThe starch structure can be divided into different levels . The low7–8, and amylose typically an order of magnitude less [The second level is the complex branched polymer comprising individual chains joined by 1→6)-α branch points. As stated, amylopectin and amylose have the same (1→4)-α and (1→6)-α bonding. Both have a broad distribution of molecular weights, with that of amylopectin typically approximately 10ude less ,6. Amylo-α branchThe number-average branching fraction of rice amylose is up to 69%; it is 48% in maize and 44% in wheat. The number-average chain length of branched amylose molecules of rice covers the range ~230–370 (which is in the middle of the range of other crops), corresponding to branching fractions of 0.175 to 0.103 . Short cX) ≤ 100, or, to be more precise, at the DP where the weight distribution  shows a distinct change, which is usually close to DP 100. Chains with DP less than this are usually assumed to belong to amylopectin, and those greater than this to amylose. It has been found that the CLDs of both the amylopectin and amylose components of starch—starch’s fine structure—are significantly correlated with various functional properties of starch, including digestibility and pasting properties [A starch solution can be separated into amylopectin-dominated and amylose-dominated distributions, by separation by whole molecule size . The range of the CLDs in amylopectin is usually taken as chains with degrees of polymerization  starch synthase, SS; (2) starch branching enzymes, SBE; and (3) debranching enzymes, DBE. We also review methods to measure these CLDs. Knowledge of this fine molecular structure of starch, and the underlying biosynthetic mechanisms, helps the understanding of starch structure–property relationships. This can help breeders to target features of starch’s fine structure by breeding or genetic modification, so as to develop starch-based foods contributing to improved health and lifestyle outcomes.When humans and other animals digest starch-containing foods, the starch is converted to glucose. The rate and location in the gastrointestinal tract of the digestion of starchy foods are significantly correlated with human health. Rapidly digested starch (RDS) leads to a spike in blood sugar, which can place a strain on the insulin system and, if this is chronic, can lead to diabetes. Slowly digested starch (SDS) reduces the glycemic load of a food product ,28, whicThe digestion rate of starch also has correlations with human mental health. For example, it has been reported that the level of blood glucose can influence mental performance, especially for demanding tasks such as memory, and that a breakfast enriched in SDS can reduce the possibility of a decline in performance later in the morning . It has The digestibility of starch in food can depend on the method used in processing this food. It has been reported  that thew(logRh).The structure of a glucose polymer can be quantified in terms of various distribution functions. As an example, for a whole starch molecule, one such distribution is the number distribution of molecules as a function of their size. Another common distribution is the weight distribution: the weight of molecules as a function of their size, m located at distances ir from the center of mass. One definition of size for any polymer molecule in a solution at any instant is the root-mean-square radius of gyration, defined as the square root of the mass average of ir  gives the average radius of gyration, as above; it also gives the weight-average molecular weight.Consider a homopolymer molecule in a solution comprising atoms or monomer units of mass minology ). In a sRh (or hydrodynamic volume Vh = 4/3 π Rh3). The IUPAC definition of the hydrodynamic radius specifically depends on the method of measurement [Vh or Rh) in the solvent, independent of their structure and composition. It is noted that this assumption has only been subjected to limited testing [Another commonly used size parameter for polymers is the SEC hydrodynamic radius surement  (Definitsurement ). The desurement —the noti testing .Rh, these having been measured independently, e.g., by MALLS, using the same solvent and SEC set-up  as those for the analyte. With the universal calibration assumption, one can then plot the elution volume as a function of Rh, giving a calibration curve. Note that this varies with the column(s) (including column age), temperature, solvent and other conditions, and even can show significant day-to-day variability; calibration must be carried out daily.Universal calibration is implemented using approximately monodisperse samples of standards (pullulan being suitable for starch) with a suitable range of molecular weights, and hence of values of X; the weight distribution in terms of size can thus be converted into the weight distribution in terms of the degree of polymerization, w(logX). For debranched starch, which is a linear polymer, one has M = M0X + 18, where M0 = 162.2 is the molecular weight of the anhydroglucose monomer unit and 18 is that of the additional water in the end groups.The preceding discussion is applicable to any polymer, branched or unbranched, of any composition. For a linear homopolymer, there is a one-to-one relation between the size of a molecule and its molecular weight, or its degree of polymerization Rh, w(log Rh) and the weight-average molecular weight, Rh in the whole sample, or as a function of Rh for size-separated samples).There is, however, no such unique relation between size and molecular weight with a (complex) branched polymer such as starch; complex branched polymers with different molecular weights and different structures can have the same hydrodynamic size. The best that can then be obtained with light scattering detection is the relative weight, and hence concentration, of the sample in that elution slice as a function of Nde(X) (the number of chains after debranching with degree of polymerization X), or the weight CLD, wde(X), or often simply w(logX). For a linear homopolymer, the two distributions are related by [The CLD is a significant determinant of starch’s digestibility and pasting properties ,19,20,21lated by w(logX) Examples are given in There are a number of techniques to measure the starch structure, for both the whole molecule and the individual chains (branches) obtained following the breakage of each (1→6)-α linkage (branch point) with a debranching enzyme. The distribution of the individual chains thus obtained is the CLD.One method to measure the CLD is fluorophore-assisted carbohydrate electrophoresis (FACE) . To prepA method to measure both the CLD and the size distribution of whole molecules is size-exclusion chromatography , which is suitable to measure the entire DP range of both debranched amylopectin and debranched amylose ,49,50. IRh during the passage of the polymer solution through the column. When using SEC on whole amylopectin molecules, band broadening means that features with close but different molecular size ranges may blend into what seems to be a single feature (SEC suffers from band broadening (unlike FACE). This is an unavoidable problem for SEC , whereby feature . SEC is w(logX), or in terms of the hydrodynamic radius, w(log Rh). The angular dependence of the intensity of MALLS is sensitive to the weight-average molecular weight, Rg, of the sample in the elution slice. If the Mark–Houwink parameters of either sample or standard are unavailable, then this will give the molecular size distribution relative to the standard, but not the absolute value. A viscometric detector is sensitive to the intrinsic viscosity and thus (with knowledge of the Mark–Houwink parameters relating the viscosity and molecular weight of a linear polymer) the number-average molecular weight, if the sample is unbranched.There are various types of detectors for SEC. The differential refractive index (DRI) is the difference in the refractive indices of the polymer solution and pure solvent and is proportional to the mass of the polymer in the solution; a DRI detector gives the SEC weight distribution in terms of the DP, w(log Rh). The independent variable is expressed logarithmically, as SEC elutes approximately (but not exactly) linearly with the size of an unbranched polymer over a moderate range, where w(log Rh) or w(logX) is approximately proportional to log Rh or logX, respectively. A MALLS detector gives the weight-average molecular weight and the average radius of gyration of the polymers in an eluent slice.SEC has some disadvantages, especially with regard to the assumptions needed for calibration. As mentioned above, SEC separates particles by hydrodynamic radius . This seRh, measured in the same solvent, temperature and SEC set-up and assuming the validity of the Mark–Houwink relation over the DP range of interest [When a MALLS detector is unavailable, the conversion from the SEC elution time to DP can be achieved by calibration with relatively monodisperse standards with known interest  and the Another method to measure the CLD is high-performance anion-exchange chromatography at a high pH with pulsed amperometric detection (HPAEC), which can be used up to DP ~ 60. However, this method suffers from mass bias ,56, whicA common method to interpret size distribution data involves calculating the average degree of polymerization  polymer. For ordinary starch, in a 2D distribution, one expects to see two “mountains”: one for long chains and a small total molecular size (amylose) and the other for short chains and a large total molecular size (amylopectin). Such distributions are very laborious to obtain experimentally [Rh) and are sufficient in amount to be subsequently subjected to enzymatic debranching. This is then followed by SEC analysis of the resulting debranched chains. Such a procedure is termed SEC × SEC separation. An example of this for ordinary starch is shown in Defining amylopectin molecules as having a large total molecular size and short chains, and amylose molecules as having a smaller total size and long chains, can lead to ambiguity, as is the case with high-amylose rices . This pmentally . First, The weight distributions of whole starch molecules have not been extensively studied. This can be ascribed to two problems.The first problem is that the commonest method for obtaining such distributions, SEC, results in shear scission with the larger starch molecules on the SEC columns and tubing, and extensive data together with dimensionless analysis  show tha4 [4; (b) the whole size range of native starch is covered. Some excellent studies on smaller starch-like polymers have appeared, e.g., [One way to overcome this would be to use a size separation technique with lower shear than that in SEC. One such technique is asymmetric-flow field-flow fractionation, AF4 . Howeverd, e.g., ,65,66,67Xmin~6 [ae) mutation of SBEIIb has been found to suppress SBE and can significantly increase the amount of amylose chains [The biosynthesis of starch is shown in Xmin~6 . An amyle chains ,76,82,83Each CLD can be seen as the sum of contributions from “enzyme sets” , which cAlk gene), which is significantly correlated to the gelatinization temperature of rice grains, and so affects rice cooking quality [japonica SSII-3 [Arabidopsis [In addition to isoforms of SS, SBE and DBE, another enzyme involved in starch biosynthesis is AGPase, which catalyzes and produces ADP-glucose. As the first step in starch biosynthesis, ADP-glucose is elongated by soluble starch synthases (SSs) through (1→4)-α linkages ,69. Ther quality ,85. The a SSII-3 ,88,89,90a SSII-3 ,71. Studa SSII-3 . Althougbidopsis  shows thbidopsis ,71,72,73Waxy (Wx) gene, which mainly controls amylose biosynthesis [GBSS both elongates amylose chains and increases the number of extra-long chains (ELCs) of amylopectin, while SS I–IV are believed to mainly act in amylopectin synthesis ,77,91,92ynthesis ,93,94,95It was first reported that GBSSI uses non-physiological concentrations of UDP-glucose, but ADP-glucose was subsequently discovered to be the preferred substrate . GBSSI aIt is found that some enzymes work on more than one DP range. Some examples of this are as follows: (1) SBE takes part in amylose synthesis ,99, as wFitting the observed CLDs to biosynthesis-based models is useful because the parameters resulting from the fitting, which together enable the whole CLD to be reconstructed, are biologically based. This should replace what is often performed at present, which involves the relative number of chains in the CLD in empirically chosen DP ranges. An empirical DP division is problematic because the inferences might change if the choice of region was to be changed .This problem can be avoided because of the development of biosynthesis-based models, which include the assumption that the DP in a given range of DP is dominated by an enzyme set, but there are contributions from other enzyme sets as well, as shown in iβ of SBE and SS for each enzyme set i, and the relative propagation rates ih of SS in these sets [ih represents the relative number of branches in given region i, and iβ reflects the number of shorter chains in region i. The theory gives a means to calculate the contribution to the overall CLD from each enzyme set, and the fitting starts by assuming only a single enzyme set in a chosen DP range. The first sets of values of the parameters iβ and ih thus obtained are then refined in the next step of the data fitting, which takes all enzyme sets into account and applies a global least-squares fit to the entire DP range.The amylopectin model developed by Wu et al.  assumes ese sets . Brieflyβ and h, which are analogous to those for amylopectin [For amylose, the model developed by Nada et al.  also invlopectin . Similarlopectin .βjAp, , the ratio of activities of SS and SBE in enzyme set j  and the number amount of the overall CLDs produced by this set to that produced by that j: hjAp, . DBE is also involved, but the mathematical development using the requirement for steady state shows that its activity is determined by those of SS and SBE. For amylose, the amylose fitting parameters, βjAm,   and hjAm,  , have the same meaning as those for amylopectin [For amylopectin, data fitting yields lopectin ,58.iβ and ih for each enzyme set. The most important use of the model fitting is that it reduces an experimental CLD to a small number of biosynthesis-based parameters, and that these parameters, together encapsulating the CLD over the entire range of starch chain lengths, may then be used to seek correlations between the structure and properties of interest. With each such correlation, it is essential to distinguish statistical coincidence from causal relations; for this purpose, one must determine whether a physically reasonable mechanism can be postulated that is consistent with each correlation—for example, that the dominant events in chain growth and stoppage are growth (propagation) by a starch synthase and stoppage by a debranching enzyme. This process can reveal mechanisms in starch biosynthesis.The models used to interpret these data were derived by extending the theory of the molecular weight distributions of linear polymers developed originally for free radical polymerization . The codStarch’s fine structure is an important factor that can affect digestibility and other functional properties, some examples of which are reviewed here. Only studies on cooked starches are considered, as humans rarely eat raw starch.1. A number of studies have reported that the DP 6–12 region of amylopectin affects the amount of RDS and SDS. It was reported that a lower proportion of short A chains (DP 6–12) was correlated with lower RDS and could contribute to a higher SDS in indica long-grain rice . It was indica long-grain rice had a lower RDS [2. The DP 13~100 region of amylopectin can also be significantly correlated with digestibility. It was reported that a higher proportion of long amylopectin chains (DP ~ 37) in ower RDS . In addiower RDS .Amylopectin, with a high branching density, short chains and shortened terminal nonreducing ends, is more slowly digested in cooked starch in maize: more and shorter short chains are slow to digest ,116,117.The chain length distribution of amylose also significantly affects digestibility, as illustrated in the following examples.1. In the DP 100–500 region of amylose, i.e., short to medium chains, it was found that the in vitro digestibility of native and cooked rice starches was influenced by both the degree of branching and amylose content ,120,121.2. The DP 1000~1500 region of amylose also has an effect. The long chains of amylose are defined as DP 500~1500. At present, the effects of amylose’s molecular fine structure, and the interactions with amylopectin molecules on starch digestibility, have been less studied. A study of cooked and retrograded rice starch reported that amylose long chains correlated with digestibility in rice, but the correlation was not as significant as that of amylose short–medium chains .The relationships between starch structural features and digestibility are shown in The rapid visco-analyzer (RVA) profile is affected by starch’s fine structural features, such as the chain length distributions of amylopectin and amylose. Both affect the rheology of suspensions of rice flour. A typical rice RVA with the explanation of different parameters has been shown in Starch’s molecular fine structure is a determinant of its functional properties. Starch’s structural features can be interpreted and fitted using biosynthesis-based mathematical models ,58. A laThis review addresses the relationship between starch’s fine structure and its functional properties, indicating the potential of modifying starch’s structural features to improve the health benefits of starchy foods. This can help breeders to target starch’s fine structure using conventional and GM methods , to adju


The aim of this ESSKA consensus is to give recommendations based on scientific evidence and expert opinion to improve the diagnosis, preoperative planning, indication and surgical strategy in Anterior Cruciate Ligament revision.Part 2, presented herein, followed exactly the same methodology as Part 1: the so-called ESSKA formal consensus derived from the Delphi method. Eighteen questions were ultimately asked. The quality of the answers received the following grades of recommendation: Grade A (high level scientific support), Grade B (scientific presumption), Grade C (low level scientific support) or Grade D (expert opinion). All answers were scored from 1 to 9 by the raters. Once a general consensus had been reached between the steering and rating groups, the question–answer sets were submitted to the peer-review group. A final combined meeting of all the members of the consensus was then held to ratify the document.The review of the literature revealed a rather low scientific quality of studies examining the surgical strategy in cases of ACL reconstruction failure. Of the 18 questions, only 1 received a Grade A rating; 5, a Grade B rating; and 9, grades of C or D. The three remaining complex questions received further evaluations for each portion of the question and were looked at in more detail for the following grades: B and D; A, C and D; or A, B, C and D. The mean rating of all questions by the rating group was 8.0 + − 1.1. The questions and recommendations are listed in the article.ACL revision surgery, especially the surgical strategy, is a widely debated subject with many different opinions and techniques. The literature reveals a poor level of standardization. Therefore, this international European consensus project is of great importance and clinical relevance for guiding the management of ACL revision in adults.Level II. Anterior cruciate ligament (ACL) revision (ACLRev) is more demanding than primary reconstruction, and the outcomes are worse , 27. TheSurgical strategy plays a key role in performing optimal ACLRev, correcting previous technical errors and addressing associated pathologies. Multiple factors must be considered to optimize the outcome. Range of motion deficits or preexisting hyperextension should be taken into account. Choosing the best graft is a further problem, as it can be limited in the revision situation, and the surgeon must be knowledgeable in multiple graft options and preparation techniques. Previous tunnel widening may limit the possibility of performing a one-stage revision, and multiple strategies exist in the management of widened and misplaced tunnels . One furMore recently, focus has been placed on limb alignment, which contributes to ligament and cartilage loading and must be considered in revision cases, both in the coronal and sagittal planes , 20. It http://www.esska.org/page/projects). The reader is cautioned that this is not a complete systematic literature review and, further, that this consensus is not focused on any specific surgical technique.The aim of this European Society for Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) Consensus is to provide a combination of “scientific” evidence-based and expert-based recommendations regarding the diagnosis, preoperative assessment, indication and management of patients with failed ACL reconstruction to further improve the outcome after ACLRev , 19. In A European ACLRev consensus project was established by the European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) between 2020 and 2022, focusing on the management of primary ACL reconstruction failure in adults. ACL revision was defined as “all surgical procedures involving replacement of the ACL graft with a new graft”. Exclusion criteria for the consensus were patients under 18 years of age, multiligament injuries involving the ACL and PCL, and any procedure where the ACL was not revised and where any additional graft was inserted. Patients who had already undergone their first revision ACL procedure were excluded.In this consensus, knee instability and laxity are defined as follows: pathological laxity as a clinical sign is “an increased passive response of a joint to an externally applied force or torque in biomechanical terms”. Laxity tests are carried out to assess knee injury and are used to evaluate the passive limits of motion in a particular direction or plane. In addition, instability is defined as a functional symptom where “an abnormal dynamic joint motion occurs in response to the complex, high-magnitude loads encountered during activities of daily living and sport activities.” For the purpose of this consensus, partial meniscectomy has been defined as resection of up to 50% of the meniscus depth with intact roots and no meniscus extrusion.The process of this consensus project was similar to previously published ESSKA consensus projects , 13 and After the second round, recommendations were rated with an average of 8.0 + − 1.1 (out of nine). The mean points assigned by each rater ranged from 7.7 to 8.7 points. Five of the 18 answers received a score of less than 8 points, and all others were scored above 8.0 points. All the answers were thus considered appropriate. Only one question was rated as Grade A, while two further questions were rated as Grade A for only a part of that question; five questions and a component of two further questions were rated as Grade B, indicating that only a low-to-moderate level of scientific evidence is available for most of the answers. A very similar finding was made for the first part of this consensus study.The following factors are relevant to the surgical strategy:The following factors influence the decision of single- versus two-stage procedures:Bone grafting is generally recommended if secure graft fixation cannot be achieved in an anatomic position due to an increased tunnel diameter. No absolute threshold exists for the “critical tunnel diameter”, with values ranging between 12 and 15 mm. In fact, the threshold may vary with regard to graft choice, drilling technique, fixation technique, and knee size.A previously partially malpositioned tunnel, which will interfere with a new anatomic tunnel, resulting in a confluent tunnel exceeding the critical diameterA previous anatomic tunnel position exceeding the critical diameterIntra-OP widening caused by difficult fixation hardware removalThree scenarios exist in which bone grafting may be indicated:However, by using specific techniques such as outside-in drilling with a different tunnel trajectory, over the top technique, using grafts with large bone blocks and large interference screws, bone grafting may not be necessary.Bone grafting is usually performed as a two-stage procedure; however, with specific techniques , bone grafting can also be performed as a one-stage procedure.If preexisting tunnels do not interfere with new tunnel placement or graft fixation, they can usually be left alone, and bone grafting is not necessarily indicated.Both autologous and allogenic bone are suitable for tunnel grafting. Autologous bone is osteogenic, osteoinductive and osteoconductive, whereas allogenic bone is mainly osteoconductive. Therefore, autologous bone may represent the best graft material, but there is some donor side morbidity. Good filling rates have been reported with both graft materials . BecauseAn interval of 3–6 months of follow-up before second-stage revision, ACLRev is recommended after staged bone grafting, and CT imaging could be considered to determine adequate graft incorporation. Incorporation of allogenic bone may require a longer time period as compared to autologous bone.An osteotomy to correct coronal malalignment is indicated in patients with varus or valgus deviation ≥ 5° accompanied by early OA, significant cartilage damage and/or symptomatic meniscal deficiency and in patients with varus or valgus deviation associated with ligamentous insufficiency . The threshold of 5° is based on common indications for varus or valgus correction reported in the literature; however, a shift towards even smaller thresholds has occurred in recent years. Therefore, an osteotomy to correct varus or valgus deviation < 5° may be indicated in selected cases, such as patients undergoing concomitant meniscal transplantation, cartilage repair procedures, or collateral ligament reconstruction. An isolated varus malalignment without the abovementioned associated conditions is not an indication per se for an osteotomy.A slope-reducing osteotomy (extension osteotomy) should be considered in patients with failed primary ACL reconstruction and a PTS  ≥ 12°, as measured on lateral radiographs . Additionally, check for laxity on the medial side, because it can also increase anterolateral instability. However, there is still a lack of high levels of evidence in existing studies.Preoperative medial laxity is a risk factor for poorer ACL revision outcomes. Consideration should be given to concomitant medial collateral ligament (MCL) reconstruction for Grades 2 and 3 (IKDC C and D) MCL laxity , posterolateral corner or complete lateral injury, should also be detected and is evidently associated with failure of revision. Clinical thresholds regarding gapping are lacking. However, a lateral or posterolateral injury must be clearly delineated from anterolateral instability (which does not cause gapping) and should be treated accordingly to prevent failure of the ACL revision graft.Meniscus substitutes and meniscus allografts are able to improve clinical outcomes in cases with selected indications. A chondroprotective effect is expected but not yet proven to occur over a long-term follow-up.Substitute: With failed previous partial meniscectomy and meniscus-related complaints, an additional meniscal substitute may be considered in rare cases, in conjunction with ACL revision for such patients (Grade C). However, the implantation of a substitute at the same time as a partial meniscectomy (“prophylactic” substitute) is not recommended (Grade A).Meniscus allograft: An additional meniscus allograft may be considered in conjunction with ACL revision in patients with failed previous total or subtotal meniscectomy and meniscus-related complaints without significant cartilage wear (Grade B). Meniscal allografting as a concomitant procedure in ACL revision reconstruction may be performed to aid in joint stability when meniscus deficiency is believed to be a contributing factor to failure (Grade D).Which previous graft has been harvested?Is there a need to fill bone tunnel(s)?Is there a need for multiligament reconstruction?What are the advantages and disadvantages of the different autografts ?What are the respective advantages and disadvantages of autografts versus allografts (see question 13). What is the allograft availability?Is it pertinent to reharvest the same graft on the ipsilateral knee or harvest from the contralateral knee (see question 15)?Are there abnormalities  of the patellofemoral joint?Before choosing the proper graft in ACLRev, the following questions should be answered:Depending on these factors, the choice is often a compromise—in other words, a necessity rather than a real choice.Allografts are more frequently used in ACL revisions than in primary ACL reconstruction. Allografts offer the advantages of decreased operative times and low average pain during the entire rehabilitation period. The disadvantages of allografts include a risk of disease transmission, immune rejection, delay in remodelling, prolonged integration process and possibly higher revision rates, depending on graft processing. Historically, the results have been recognized to be inferior when using irradiated grafts. Nonirradiated grafts (cryopreserved or fresh frozen) are plausible alternatives to autografts, but it is unclear whether the failure rates are comparable, and caution still remains for the use of allografts in younger patients. Such patients tend to be more active, and there is increasing understanding of the higher risks in this age group. The evidence is weak, but allografts in young patients are likely to carry an increased risk of failure . This isThe use of synthetic grafts is not recommended (Grade B). For synthetic augmentation, there are currently insufficient data for an evidence-based recommendation (Grade D).Contralateral graft harvesting is considered a valid alternative to ipsilateral autografts or allografts.Although ACL reconstruction using a reharvested BPTB tendon may be possible, the tendon quality  is lower than that from a primary tendon harvest, and there is no available literature concerning the quadriceps tendon.The same requirements regarding graft thickness and length are necessary for the grafts used in revision surgery as for those used in primary ACL surgery. A minimum graft diameter of 8 mm is advised and is dependent on many factors .Infection after primary ACL reconstruction has a low incidence, and there is little evidence to guide the correct treatment. However, in the case of a suspected infection, it is mandatory to perform blood tests and joint aspiration . Tissue biopsy may be important to rule out low-grade infection in case of doubt and to identify bacteria .A multistaged procedure in suspected low-grade infection is mandatory, with thorough debridement  and antibiotic therapy prior to second-stage ACL reconstruction.Soaking the graft in an antibiotic  solution prior to graft implantation is a valid option to reduce the incidence of postoperative septic arthritis. However, the development of resistance may be of concern (Grade D).The results of this project have provided a consensus for ACLRev surgery. The conclusions are based on the input of experts from all over Europe. The proposed recommendations of the consensus are very important due to the limited general agreement in the management of failed ACL reconstruction. Of particular concern is to determine an appropriate surgical strategy tailored to the specific patient in question. Surprisingly, the ESSKA ACLR Consensus shows that a similar agreement regarding the surgical strategy has been reached, as was the case for the diagnostics and preoperative planning. The methodology of the process has already been discussed in Part I .ACLRev is more demanding than primary reconstruction, and the outcomes are worse , 27. TheAnother difficult topic is when to perform an additional osteotomy, either to correct the tibial slope to improve stability or to unload a damaged compartment where there has been joint surface damage . While tAnother difficult topic is when and how to address associated peripheral ligamentous lesions. Some surgeons are of the opinion that an additional extraarticular anterolateral procedure is key in every ACLRev case, whereas some other surgeons are more convinced that an individualized approach should be adopted. Factors that are in strong favour for an additional extraarticular anterolateral procedure are patients presenting with gross laxity  of AP instability and/or in pivoting sports or in hyperlaxity).The management of associated ligamentous lesions on the medial side is a much more controversial subject. Biomechanical studies have shown that partial and complete medial collateral ligament tears increase the load on the ACL . This haWhile the isolated effect of most procedures is often quite clear, complex combined surgeries are less well understood. Is tibial slope correction appropriate in the first ACLRev? Does this change according to meniscal status? Can some degrees of increased slope be addressed with additional extraarticular anterolateral procedures? These complex topics are currently evolving and may necessitate an updated consensus in the future.There are some limitations in this work: the main one is that the scientific level of the answers is not homogeneous. Concerning the answers with a low level of scientific evidence, the opinion of the experts has been used to validate the proposed recommendations. In the future, research will probably provide us with different answers from those published in this article.Since the level of scientific evidence is different for every question, a grading of recommendation was performed for each statement (Grade A–D).http://www.esska.org/page/projects).More information about this consensus as well as about the included references can be found on the ESSKA website (The second part of the European consensus on ACLR surgery focuses on the most important aspects to be faced to plan an adequate surgical strategy after primary ACL reconstruction failure.This represents a second step following the previously described work on diagnosis and preop planning. The consensus aims to propose a method for the standardization of the strategy for ACLRev surgery, according to current scientific evidence and clinical expertise. The ultimate goal is to improve the outcomes of this complex surgery, which requires surgical experience.


Compared to the native counterparts, the color analyses showed that the modified starches from TK11 and TCSG2 exhibited decreased brightness (L*)/whiteness index (WI) values with marked color difference values (∆E) ranging between 6.32 and 9.39 and 10.67 and 11.32, respectively, presumably due to the protein corona formed on the surface of SNPs which induced the browning reaction during the treatments. The pasting properties revealed that the modified starches displayed restricted swelling power with extremely low pasting viscosities, reflecting that they were highly thermally stable. The modified starches, especially those treated with an extended annealing incubation, exhibited marked decreases in the rate and extent of digestion and estimated glycemic index due to the honeycomb-like agglomerates comprising an assembly of densely packed SNPs. The results could provide helpful information for the preparation and characterization of the crystalline SNPs for potential applications such as emulsion stabilizers for Pickering emulsion and health-promoting ingredients.Starch nanoparticles (SNPs) have unique attributes that make them suitable for specific applications. In this study, we assessed the optimum conditions for the fabrication of SNPs from the rice starches of low- (TCSG2) and medium-amylose rice lines (TK11) using pullulanase debranching combined with annealing treatment and evaluated their physicochemical and digestion properties. The highest crystalline SNP percent recoveries of 15.1 and 11.7% were obtained from TK11 and TCSG2, respectively, under the following debranching conditions: 540–630 NPUN/g, pH 5.0, 60 °C, and 12 h. The percent recovery of the crystalline SNPs by the combined modification of the debranching and the annealing treatment with an extended annealing incubation prepared from TK11 and TCSG2 was significantly increased to 25.7 and 23.8%, respectively. The modified starches from TK11 had better percent recovery of the crystalline SNPs than those from TCSG2. They exhibited a higher weight-average molecular weight ( Starch is the most abundant constituent of staple foods in the human diet, serving as the primary energy source. For nutritional merits, starch can be classified into three fractions, namely, rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) based on digestion rate and extent . VariousStarch nanoparticles (SNPs) are attracting significant attention due to their novel attributes beneficial to specific applications. It has been reported that starch nanoparticles (SNPs) are highly inaccessible to digestive enzymes exhibiting a two-phase digestion process due to the densely packed structure acting as a barrier to enzymatic hydrolysis exerted by the molecular structural rearrangement and the increased short-range order ,4,5. In It has been reported that SNPs can be fabricated through top-down and bottom-up approaches. The top-down approach for the production of SNPs utilizing starch as a precursor can be categorized into conventional methods such as acid hydrolysis and non-conventional methods such as enzymatic debranching, milling, nanoprecipitation, microemulsion, sonification, ultrasound combined with non-thermal plasma, heat moisture treatment, and high hydrostatic pressure ,6,9. EnzTo the best of our knowledge, the effects of debranching conditions and the combined annealing treatment on the formation of SNPs have yet to be systematically investigated. The objective of this study was to examine the effect of debranching conditions  and the combined annealing treatments with different annealing temperatures and incubation times on the production of crystalline SNPs from the rice starches of two rice lines varying in amylose content. We assessed the percent recovery of the crystalline SNPs and their pasting properties using a rapid visco analyzer, surface morphology using scanning electron microscopy, color attributes using a colorimeter, and in vitro digestion properties.The polished rice kernels from two rice lines, namely, Taikeng 11 (TK11) and Taichung Sen glutinous 2 (TCSG2), were used in this study. Pullulanase , pancreatic α-amylase  and dimethyl sulfoxide (DMSO) were obtained from Sigma-Aldrich Chemical Co. . Amyloglucosidase  and a total starch assay kit were obtained from Megazyme International Ireland Ltd. . All other reagents used in the present study were of analytical grade.Rice starches from the two rice lines were isolated using an alkali extraction method . Brieflyw/v, in diluted pH 5.0 sodium acetic buffer) was prepared and pregelatinized in boiling water for 15 min prior to autoclaving for 30 min at 121 °C. To optimize the effect of debranching conditions on the formation of crystalline SNPs, the enzymatic debranching was performed at different concentrations of pullulanase , debranching temperatures , debranching time  and pH conditions . The mixture was then autoclaved at 121 °C for 1 h for enzyme deactivation. The samples were cooled at 4 °C for 24 h before being oven-dried, grounded, and screened through an 80-mesh sieve for further measurement.Rice starch slurry  according to an approved method AACC 76–13.01 . The tot3 at a 0.6 mL/min flow rate. Standard dextrans  with different molecular weights (MWs) were used for calibration. The weight-average MW (wM) and weight-average degree of polymerization (wDP), and polydispersity (PDI) were calculated according to a previous study [Gel permeation chromatography measurements of the samples were performed according to a previous study  with slius study .L* axis denotes lightness from 100 (white) to 0 (black); the a* axis denotes red  to green ; and the b* axis denotes yellow  to blue . The total color difference (∆E) between the modified and native starches was also calculated. The total color difference (∆E) and whiteness index (WI) were, respectively, determined as follows:The color traits of the samples were determined using a colorimeter . The CIELAB color coordinates were assessed: the w/v) were tested using a rapid visco analyzer  based on the procedure described by a previous study [Pasting properties of starch sample suspensions . The starch samples coated with a gold layer were mounted on circular aluminum stubs using double-sided carbon tape. Surface structures were recorded under an acceleration potential of 15 kV at a magnification of 1000× with a working distance of 14 mm to the samples.Determination of in vitro kinetics of starch digestion was conducted according to the method described by previous studies ,13,14,15C, ∞C, and k are starch hydrolysis (%) at time t and 180 min, and the first-order kinetic rate constant, respectively. The rate and extent of digestion and estimated glycemic index were determined according to a previous study [RDS), slowly digestible starch (SDS), and resistant starch (RS), were obtained according to previous studies [G0, G20, and G120 are the quantities of glucose after 0, 20, and 120 min of hydrolysis, respectively.The starch digestogram was assumed to follow a first-order kinetic model using Microsoft Excel SOLVER based on a nonlinear optimization algorithm :(1)C=C∞ using SPSS version 18.0 software .Data obtained from three independent measurements were expressed as means ± standard deviation. Analysis of variance (ANOVA) was performed, and significant differences were tested by Duncan’s multiple range test  with much larger wDP and PDI . However, there were no significant differences in the MW distribution patterns between the one-day and two-day annealed starches, which had approximately the same wM, wDP, and PDI values, as shown in L*) of the native starches isolated from TCSG2 and TK11 were 96.91 and 96.85, while their whiteness indices (WI) were 96.74 and 96.63, respectively. This suggests that the high purity of starch was obtained from the isolation. The modified starches showed lower L* and WI, and marked color differences (∆E) compared to the native starches. Increasing annealing incubation time led to decreases in L* value and WI accompanied by increases in a* and b* values, as shown in The results of the color parameters of the native starches and the modified starches are shown in eGI) are presented in eGI values of the native starches in cooked form from TCSG2 and TK11 were 94.89 and 87.41, respectively, regarded as high-glycemic-index (GI) foods. Moreover, the native starches had a relatively high digestion rate constant (k) and hydrolysis percentage at 180 min of digestion time point (∞C) due to the amorphous gelatinized starches being extremely susceptible to digestion. The results were comparable to previous studies [∞C, k, and eGI. The five-day annealing treatment led to a significantly lower digestion rate and extent than the one-day annealing treatment. The results suggested that the modification treatment induced the formation of double-helical nanocrystals, which could increase their resistance to digestion, and the extended annealing incubation time could further increase their crystalline size and perfection, which were more resistant to digestive enzymes. The rapidly digestible starch, slowly digestible starch, and resistant starch contents are shown in Starch digestograms of the native starches and the modified starch are shown in  studies ,38,39. SThe highest percent recovery of the crystalline SNPs from two rice lines varying in amylose content using the debranching treatment was obtained under the following optimum conditions: 540–630 NPUN/g starch, pH 5.0, 60 °C, and 12 h. The debranching combined with additional annealing treatment led to the markedly increased percent recovery of SNPs. The debranching combined with five-day annealing incubation at 35 °C led to the highest increase in percent recovery. The starches from the rice line with higher amylose content resulted in a better percent recovery of the crystalline SNPs. Our results showed that the debranching with the optimum conditions in combination with the annealing treatment enhanced the crystalline SNP production to a great extent. The molecular weight distribution and molecular uniformity of the modified starches were strongly affected by the amylose content of the starch as a top-down precursor. Color examination revealed that the modified starches exhibited decreased brightness/whiteness values with a marked total color difference value due to the protein corona formed on the surface of the SNPs inducing the browning reaction during the fabrication. The pasting profiles and the SEM images revealed that the modified starches displayed honeycomb-like structures of agglomerate, comprising an assembly of densely packed SNPs. The densely packed structure contributed to their thermal stability and resistance to digestive enzymes, substantiated by their low rate and extent of digestion and estimated glycemic index, and highly resistant starch content. The results can help to elucidate the optimum fabrication conditions of the crystalline SNPs and to characterize the physicochemical properties for their potential applications, such as emulsion stabilizers in Pickering emulsion and health-promoting ingredients.