Multilevel lumbar fusion with posterior pedicle screw fixation is a widely performed surgical procedure for the management of adult spinal deformity. However, there has not been a comprehensive biomechanical study on the different types of fusion levels in terms of stability and possible complications. We aimed to investigate the biomechanical properties of multilevel lumbar fusion according to different types of upper and lower fusion levels. Six different types of fusions were performed using three-dimensional finite element models. Type A and B referred to the group of which upper fusion level was L1 and T10, respectively. Subtype 1, 2, and 3 referred to the group of which lower fusion level was L5, S1, and ilium, respectively . Flexion, extension, axial rotation, and lateral bending moments were applied, and the risk of screw loosening and failure and adjacent segment degeneration (ASD) was analyzed. Stress at the bone-screw interface of type B3 was lowest in overall motions. The risk of screw failure showed increasing pattern as the upper and lower levels extended in all motions. Proximal range of motion (ROM) increased as the lower fusion level changed from L5 to S1 and the ilium. For axial rotation, type B3 showed higher proximal ROM (16.2°) than type A3 (11.8°). In multilevel lumbar fusion surgery for adult spinal deformity, adding iliac screws and increasing the fusion level to T10-ilium may lower the risk of screw loosening. In terms of screw failure and proximal ASD, however, T10-ilium fusion has a higher potential risk compared with other fusion types. These results will contribute for surgeons to provide adequate patient education regarding screw failure and proximal ASD, when performing multilevel lumbar fusion. Multilevel lumbar fusion with posterior pedicle screw fixation is a widely performed surgical procedure for the management of adult spinal deformity . As globMultilevel lumbar fusion surgery has the advantage of spinal alignment correction; however, complications such as screw breakage and loosening or adjacent segment degeneration may occur. To avoid these complications associated with lumbar fusion surgery, artificial disc replacement (ADR) was developed for degenerative lumbar spinal diseases which do not require alignment correction. In a study using finite element analysis, single level ADR showed satisfactory results; however, multilevel ADR showed hypermobility which may lead to alter natural movement of spine and implant failure . In clinHowever, to our knowledge, there has not been a comprehensive biomechanical study on the different types of fusion levels in terms of stability and possible complications. Most previous studies were confined to complications about L5-S1 segment or proximal adjacent segment –14. FurtUsing finite element analysis, we therefore asked: (1) How different is the risk of screw loosening between the fusion types? (2) How different is the risk of screw failure between the fusion types? (3) How different is the risk of adjacent segment degeneration (ASD) between the fusion types?Ethical approval for this study was obtained from the Institutional Review Board (IRB) of the corresponding author's hospital (Yonsei University IRB and Ethics Committee: 4-2020-0060). All methods were performed in accordance with the Declaration of Helsinki and Yonsei University institutional guidelines. Informed consent was obtained from the subject.A three-dimensional (3D) thoracolumbar spine and pelvis model was constructed using computed tomography data from a normal 57-year-old male, with the slice thickness of 2-mm, along with a previously validated lumbar spine model called T9-Pelvis  17]. Al. Al17]. We used Abaqus  to perform finite element analysis and computer-aided engineering of the spine model. We constructed the thoracolumbar spine ligaments as a truss element including the anterior longitudinal ligament, posterior longitudinal ligament, ligamentum flavum, intertransverse ligament, interspinous ligament, supraspinous ligament, and capsular ligament. We constructed the pelvic ligaments as a spring including the anterior sacroiliac ligament, posterior sacroiliac ligament, interosseous sacroiliac ligament, sacrospinous ligament, sacrotuberous ligament, superior pubic ligament, arcuate ligament, inguinal ligament, and iliolumbar ligament. The Young's modulus, Poisson's ratio, and stiffness coefficient were applied to each moiety using previously published data in the literature Tables  18–23].–23.18–23We used two methods to validate the finite element analysis results. (1) The lumbar lordosis angle of the 3D model was measured and compared with the angle in the normal range . (2) TheWe produced the surgical model by importing the oblique lateral interbody fusion (OLIF) and posterior lumbar interbody fusion (PLIF) cage  into Abaqus. The OLIF/PLIF cage dimensions were 22 mm/26 mm in length, 22 mm/14 mm in height, and 12°/6° in angle measure, respectively, according to the lumbar model height and angle. The discs of each intact lumbar segment were removed; OLIF cages were inserted into L1-L5, and PLIF cages were inserted into L5-S1. The pedicle screw system  was used for posterior fixation: 6.5 mm in diameter and 45 mm in length for the spine and 8.5 mm in diameter and 80 mm in length for the ilium. The pedicle screw was inserted through the center of the pedicle and parallel to the endplate, and the iliac screw was inserted through S2 ala  . Next, aSix different fusion types for comparative analysis were made. Type A and B referred to the group of which upper fusion level was L1 and T10, respectively. Subtype 1, 2, and 3 referred to the group of which lower fusion level was L5, S1, and ilium, respectively: Type A1, L1-L5; Type A2, L1-S1; Type A3, L1-ilium; Type B1, T10-L5; Type B2, T10-S1; Type B3, T10-ilium .To apply a physiological load, both acetabulum bones were fixed in all degrees of freedom, assuming standing on two legs. A pure moment of 10 Nm was applied to the uppermost segment (T9) endplate in the direction of flexion, extension, axial rotation, and lateral bending according to the spinal mobility. A compressive follower load of 400 N was applied according to the curvature of the vertebral segment  29]. Ti. Ti29]. Stress at the bone-screw interface of type B3 was lowest in overall motions. Subtype 2 showed higher peak von Mises stress (PVMS) than subtype 1 and 3. For flexion and extension, subtype 1 and 3 showed similar results within type A and B group while type A showed higher PVMS than type B. For axial rotation, type B1 showed higher PVMS than B3. PVMS was noted at the upper end level in subtype 3 and axial rotation motion in all types, while PVMS was noted at the lower end level in other types and motions .PVMS at the screw increased as the lower fusion level changed from L5 to S1 and the ilium. Type B group showed slightly higher results in all motions than the type A group. The highest PVMS was identified in axial rotation motion, and type B3 showed the highest PVMS (267.8 MPa) among the six types. The measured stress in all motion and types was less than the yield strength (880 MPa) of Grade 5 titanium (Ti-6Al-4 V) . Among aOverall, the proximal ROM increased as the lower fusion level changed from L5 to S1 and the ilium. For flexion, extension, and lateral bending, type B group showed similar or slightly higher proximal ROM than each corresponding type A. For axial rotation, type B3 showed higher proximal ROM (16.2°) than type A3 (11.8°). Despite interbody fusion with two cages in the L5-S1 segment, fine motion in L5-S1 was identified in subtype 2 group, whereas subtype 3 group showed no motion .Advantages of multilevel lumbar fusion with posterior pedicle screw fixation have been reported in numerous studies, and possible complications also have been researched using various methods. However, to our knowledge, there has not been a comprehensive study on biomechanical properties of different fusion levels using 3-dimensional finite element method. We found that adding iliac screws and increasing the fusion level to T10-ilium may lower the risk of screw loosening. Second, in terms of screw failure and proximal ASD, T10-ilium fusion model showed higher potential risk compared with other fusion types. Based on these results, it can be suggested that T10-ilium fusion is recommendable for spinal deformity correction and maintaining the stability, although there is a potential risk of screw failure and proximal ASD; therefore, surgeons should provide adequate patient education regarding screw failure and proximal ASD, when performing T10-ilium fusion.In terms of screw loosening, we found that type B3 was most appropriate in overall motions. The stress at the bone-screw interface in fusion down to S1 is 58% higher on average than that in fusion down to L5 or the ilium regardless of the upper fusion level. This result was consistent with previous literature findings –33. AlsoThe risk of screw failure showed increasing pattern as the upper and lower levels extended in all motions . PVMS waRegarding lumbosacral junctional failure, we identified the superiority of fusion to the ilium compared with that to S1 using ROM analysis. Several previous studies have reported that extending the fusion to the ilium may prevent complications that arise from fusion to only S1 , 34, 35.The risk of proximal ASD increased as the fusion range increased to S1 and the ilium. The overall proximal ROM of type B group was similar or slightly higher, with an average of 13%, than that of type A group, a finding that was somewhat different from that of a previous clinical study . InteresThis study has several clinically relevant findings. Surgeons can determine the surgical outcome of patients according to various fusion levels. The risk of screw loosening and failure was numerically identified and can be applied to clinical practice. Furthermore, our results can be used as material for patient education.Our study has limitations. First, we did not change the rod structure or material, such as the cobalt chrome rod or multiple-rod constructs. We considered the most used material and surgical technique to date to limit the variables. Further studies are needed to confirm the effect of the rod structure. Second, our model is based on a normal male individual; thus, it does not reflect the status of undercorrection or overcorrection and the poor bone quality observed in patients. Constructing a spine model based on a real patient with adult spinal deformity remains technically challenging. Further technical research is required to construct a real deformed spine model. In addition, the models in this study were considered as linear since we intended to see the trends between the models. We will apply the anisotropic properties of the bone in the future research. Finally, we assumed the screw-bone interface to be completely fused and fixed state and simplified the screw threads as previous finite element studies –45 sinceIn multilevel lumbar fusion surgery for adult spinal deformity, adding iliac screws and increasing the fusion level to T10-ilium may lower the risk of screw loosening. In terms of screw failure and proximal ASD, however, T10-ilium fusion has a higher potential risk compared with other fusion types. These results will contribute for surgeons to provide adequate patient education regarding screw failure and proximal ASD, when performing multilevel lumbar fusion.


Recently, the synthesis of a series of human dhs inhibitors led to 6-bromo-N-(1H-indol-4yl)-1-benzothiophene-2-carboxamide, a potent allosteric inhibitor with an IC50 value of 0.062 µM. We investigated this allosteric dhs inhibitor in Plasmodium. In vitro P. falciparum growth assays showed weak inhibition activity, with IC50 values of 46.1 µM for the Dd2 strain and 51.5 µM for the 3D7 strain, respectively. The antimalarial activity could not be attributed to the targeting of the Pfdhs gene, as shown by chemogenomic profiling with transgenically modified P. falciparum lines. Moreover, in dose-dependent enzymatic assays with purified recombinant P. falciparum dhs protein, only 45% inhibition was observed at an inhibitor dose of 0.4 µM. These data are in agreement with a homology-modeled Pfdhs, suggesting significant structural differences in the allosteric site between the human and parasite enzymes. Virtual screening of the allosteric database identified candidate ligand binding to novel binding pockets identified in P. falciparum dhs, which might foster the development of parasite-specific inhibitors.The treatment of a variety of protozoal infections, in particular those causing disabling human diseases, is still hampered by a lack of drugs or increasing resistance to registered drugs. However, in recent years, remarkable progress has been achieved to combat neglected tropical diseases by sequencing the parasites’ genomes or the validation of new targets in the parasites by novel genetic manipulation techniques, leading to loss of function. The novel amino acid hypusine is a posttranslational modification (PTM) that occurs in eukaryotic initiation factor 5A (EIF5A) at a specific lysine residue. This modification occurs by two steps catalyzed by deoxyhypusine synthase ( E [Almost 50 years after the establishment of the WHO’s Global Malaria Eradication Programme, significant decreases in mortality rates have been achieved and an increasing number of countries have been certified as malaria-free. This success prompted a bold plan to reduce 90% of deaths caused by malaria until 2030  and to eE . NeverthPlasmodium has been accelerated by molecular genetics, i.e., genome editing by CRISPR-Cas9 [trans- or cis-acting genetic methods, which attenuate the expression of a gene of interest. Trans-acting reverse genetic tools are short hairpin RNA (shRNA) [Plasmodium due to the absence of a canonical RNAi regulated pathway in the parasite [cis-acting reverse genetic tools do not show off-targeting effects; however, manipulation of the parasite’s genome is required that involves transfection of a plasmid encoding the sequence of a gene of interest mediating homologous recombination [cis-acting reverse genetic tools has been developed which enable conditional attenuation of expression of a gene of interest [The discovery of novel targets in SPR-Cas9  and reve (shRNA)  or antisparasite  and off-bination  and a seinterest  or inducinterest .cis-acting tools for regulating gene expression at the RNA level in Plasmodium is the glmS riboswitch. Originally, this regulatory element was discovered in the 5′-UTR of glucosamine-6-phosphate synthase in bacteria [glmS riboswitch downstream of the gene of interest (including drug targets) by an integration vector [One of the most widely used bacteria . In prinn vector  that is n vector  -1-benzothiophene-2-carboxamide -based in vitro method was employed. The determined IC50 value for 6-bromo-N-(1H-indol-4yl)-1-benzothiophene-2-carboxamide is 46.1 µM for the chloroquine-resistant Dd2 strain, which confers the chloroquine-resistant isoform of the chloroquine resistance transporter (CRT), , . In contectively . These d50 value of 51.5 µM -1-benzothiophene-2-carboxamide can still be attributed to dhs targeting, since the spermidine analog N1-guanyl-1,7-diaminoheptane demonstrates modest potent antimalarial activity via inhibition of P. falciparum dhs [dhs targeting by chemogenomic profiling with the transgenic P. falciparum parasites PfDHS_glmS and the ribozyme-inactive Pfdhs_M9. In chemogenomic profiling, GlcN co-treatment sensitizes the Pfdhs_glmS, but not the Pfdhs-M9 parasite to dhs-targeting compounds [N-(1H-indol-4yl)-1-benzothiophene-2-carboxamide show that co-treatment with 2.5 mM GlcN does not sensitize the Pfdhs_glmS (Pfdhs-M9 parasite (2 EC50 (−GlcN/+GlcN) ratio is not significantly greater than 0 for transgenic parasites treated with the DHS allosteric inhibitor or the control antimalarial compound pyrimethamine, an inhibitor of dihydrofolate synthase, an enzyme that participates in folic acid biosynthesis (N-(1H-indol-4yl)-1-benzothiophene-2-carboxamide does not inhibit P. falciparum growth via targeting of dhs.It is possible that the weak growth inhibition of arum dhs ,14. Therdhs_glmS A or Pfdhparasite B. Furtheynthesis C. We conN-(1H-indol-4yl)-1-benzothiophene-2-carboxamide was performed. In these experiments, we employed purified enzyme preparations of P. falciparum DHS and analyzed the peptide hydrolysates for the presence of deoxyhypusine by GC/MS. First, relative quantification was employed to determine the inhibitory activity of the allosteric inhibitor. Thus, deoxyhypusine was quantified with external calibration as described in [dhs inhibition of approximately 45% at an inhibitor concentration of 0.4 µM relative to the positive control without an inhibitor could be detected -1-benzothiophene-2-carboxamide that five amino acids of the allosteric binding site in human DHS are involved in the inhibitor interaction: (i) Asn 267 and Lys329 form hydrogen bonds with the inhibitor; (ii) Asp238 interacts via a crystal water molecule; (iii) His288 is of importance in the NH-π interaction; and (iv) Leu281 associates with the bromide of the thiophene ring. However, of the five interacting amino acids, only Asp238, Asp267 and Leu281 are present in parasite DHS.The aforementioned results challenged us to identify a putative allosteric site in the DHS enzyme of the parasite. Indeed, we localized four possible binding sites in the amino acid alignment that were present in human DHS (marked in green) . These bP. falciparum strain 3D7, the co-crys-tallized human DHS with the allosteric inhibitor was used as a template for 3D-structure modeling [Based on the amino acid sequence of DHS from modeling ,18 usingmodeling  and the modeling . The resmodeling  was perf26H27NO4; MW: 417.5 g/mol. Compound ID: CHEMBL: 476316)  A; (ii) N 476316) B.s-protein alpha subunit [Interestingly, the first compound, a benzoic acid derivative, possesses antiproliferative activity against human HL60 cells, while the second compound with a benzene–sulfon–amide structure targets the human cysteinylleukotriene receptor1  with ant subunit , a key e1  Finger-print of Open label Fastsearch algorithm . Surprisingly, the predicted allosteric inhibitor, i.e., compound 1 A, reveal1 C which imosquito . Secondlmosquito . GossypoIn recent years, understanding the molecular regulation of allosteric modulation has attracted considerable attention in drug discovery ,28. ThisTrypanosoma cruzi [T. brucei DHS is allosterically regulated by a dead paralog [T. brucei and the co-crystallized human DHS structure from P. falciparum with the allosteric inhibitor. However, only the A chain has a Qmean score of 0.57, suggesting significant structural differences between plasmodial DHS and the enzyme from T. brucei. Moreover, the amino acid identity is only 34%. This result furthermore confirms the phylogenetic distance of the DHS protein between Apicomplexan parasites and Trypanosomatides.The relevance of allosteric research for combating infectious parasitic diseases has been demonstrated in the case of the American trypanosomiasis (Chagas disease), where pockets with allosteric potential were identified and characterized in a cysteine protease (cruzain) in efforts to inhibit the causative agent ma cruzi . In this paralog , which i paralog  using thN-(1H-indol-4yl)-1-benzothiophene-2-carboxamide, against human DHS prompted us to investigate its efficacy against the orthologue from Plasmodium. The DHS protein catalyzes the regulatory step in hypusine biosynthesis, activating eukaryotic initiation factor 5A (EIF5A), which in turn promotes translation of mRNAs with polyproline motifs [N-(1H-indol-4yl)-1-benzothiophene-2-carboxamide was identified with potent inhibitory activity through binding to the allosteric site in human DHS [P. falciparum DHS protein. This was confirmed by a relative DHS inhibition of approximately 45% at an inhibitor concentration of 0.4 µM relative to the positive control. A further increase in the allosteric inhibitor dose did not prove dose-dependent inhibition. In contrast, CNI-1493, a competitive human DHS inhibitor, showed dose-dependent inhibition [The recent identification of an allosteric inhibitor, i.e., 6-bromo-e motifs  exhibitie motifs , but it uman DHS . The dathibition  of the p50 of 0.112 µM for xanthurenic acid and an IC50 of 0.310 for gossypol .ICy et al.  with modPlasmodium falciparum PfDHS_glmS and the inactive variant PfDHS_M9 [For dose–response growth inhibition assays, transgenic PfDHS_M9  were empPfDHS_M9 ,36. RingPfDHS_M9 . The bac50 values. The ratio of 50% growth inhibition constants (EC50) between −GlcN and +GlcN conditions was determined using the EDcomp in drc. EC50 ratios and confidence intervals were plotted using ggplot2 in R.The normalized growth data from dose–response assays were analyzed using the drc package  in R verN-(1H-indol-4yl)-1-benzothiophene-2-carboxamide and pyrimethamine as a control (n = 4). The maximum dose of the inhibitor compound was 50 µM.To determine the effect of GlcN on growth inhibition, parasites were co-treated with 2.5 mM GlcN. The growth inhibitors employed in this experiment were: 6-bromo- control . CompounP. vivax and recombinant, truncated P. falciparum DHS [P. vivax EIF5A were N-terminally histidine-tagged fusion proteins in recombinant pET-15b vectors and successfully expressed in E. coli BL21(DE3). After cell lysis, purification by nickel-chelate affinity chromatography under native conditions was performed. A subsequent buffer change with 0.1 M glycine/NaOH buffer was employed. The enzyme activity assay was performed in a total volume of 1 mL, containing 25 μg plasmodial DHS, 40 μg purified P. vivax EIF5A precursor protein, 4 mM spermidine, 3 mM NAD, 147 μL protease inhibitor cocktail  and 0.1 M glycine NaOH buffer and different allosteric inhibitor concentrations ranging from 0.4 µg to 0.8 µg/µL. In parallel, negative controls were performed without the allosteric inhibitor. Incubation took place at 37 °C in a shaker overnight and was stopped by freezing at −80 °C. For further analysis, two-step size exclusion chromatography with Amicon-Ultracel filters  of 30 kDa and 100 kDa pore size [The first step of EIF5A modification was performed with recombinant, purified EIF5A from arum DHS . Both plv/v)) was used for esterification of the carboxyl group and the sample was derivatized at 110 °C for 20 min. Within the next step, the derivatization reagent was removed at 110 °C by a gentle steam of nitrogen. The amino function was subsequently derivatized using 250 μL of a mixture of trifluoroacetic acid anhydride and trifluoroacetic acid ethyl ester (1:2 (v/v)). The mixture was added to the sample and heated at 130 °C for 10 min. Removal of the reagent was performed at room temperature by a gentle steam of nitrogen. Next, an additional derivatization step was necessary for the hydroxyl group of hypusine. This was achieved by adding 100 μL hexamethyldisilazane and subsequent heating of the sample for 15 min at 70 °C. A supplementation of 50 μL of dichloromethane followed before the solution was transferred to the GC vial before injection. For GC/MS analysis, an Agilent Technologies 7890 A GC-System with MS detector (MS Agilent Technologies 5975 C inert MSD with Triple-Axis) and a DB5-MS capillary column (30 m × 250 μm i.d. × 0.1 μm film thickness) from Agilent  was employed. An injection volume of 1 μL was used and applied in the splitless mode using helium as carrier gas with a flow rate of 1 mL/min. The following temperature program was used: Maintenance of a temperature of 50 °C for 0.75 min. Ramping to 75 °C was achieved with 50 °C/min and kept for 1 min. Next, an increase in the temperature with 6 °C/min to 280 °C was performed with a final hold for 10 min. Selected ion monitoring (SIM) was applied to obtain the chromatogram, i.e., for norvaline m/z = 126, 168 and 199, and for deoxyhypusine m/z = 126, 180 and 533, respectively. To quantify the respective substances, the sum of the signal intensities of each of the three ions was accumulated. Determination of the absolute inhibition of P. falciparum DHS by the small-molecule inhibitor compound was established, using deoxyhypusine [The GC/MS method for the analysis of deoxyhypusine was developed according to an approach which was previously described . A totalhypusine  and norvN-(1H-indol-4yl)-1-benzothiophene-2-carboxamide, a potent allosteric inhibitor of human DHS, was found to show weak growth inhibition activity against P. falciparum, which cannot be attributed to the targeting of P. falciparum DHS. Enzyme inhibition assays confirmed the lack of activity for this compound against P. falciparum DHS, pointing to important differences in allosteric binding sites between human and parasite DHS.6-bromo-


Based on pilot-scale twin-screw reactive extrusion, the structural and rheological properties of controlled-rheology polypropylenes (CR-PPs) are investigated, where the effects of peroxide content and extrusion conditions such as screw configuration, extrusion temperature, and screw speed are prioritized. The active chain cleavage reaction by a small peroxide content of less than 600 ppm inside the extruder gradually increases the melt index and narrows the molecular weight distribution of CR-PPs, thereby affording favorable properties that are applicable to the fiber spinning process. The mechanical properties of CR-PPs are slightly degraded owing to the generation of unsaturated chain ends during the reactive extrusion, which suppresses crystal growth. Under all extrusion conditions, the chain scission and thermal degradation of polypropylene samples occur actively in the harsh twin-screw extruder compared with those in the mild twin-screw extruder. Finally, it is confirmed that CR-PPs can be suitably applied to the melt-spinning process for staple fiber production, thereby guaranteeing a more stable spinning process window against draw resonance instability. Polypropylene (PP), as one of the most versatile thermoplastics, has a wide range of uses, including plastic packaging films, membranes, textiles, and high precision plastic parts. It is well established owing to its excellent mechanical properties and chemical resistance at reasonable prices. Considering their outstanding processability, many versatile PP products have been manufactured using various polymer processing methods, such as injection molding, extrusion, and thermoforming . Among tControlled rheology is a method for regulating the melt index (MI) of polymers by incorporating various types of peroxides for processability and narrow MWD. During the extrusion process, peroxides are pyrolyzed into peroxyl radicals, which can transform polymers into low-molecular-weight ones by breaking the polymer backbone through chain scission ,13,14,15In addition, many studies have been carried out regarding the changes in various properties of PPs due to peroxide-induced chain scission ,20,21,22Scrutinizing the effect of process conditions during reactive extrusion is crucial when adjusting the properties of CR-PPs ,25,26,27To date, most studies regarding CR-PPs have primarily focused on degradation and rheological changes relative to peroxide content, which were observed using lab-scale mixers or extruders. However, pilot-scale production presents significant challenges such as scale-up development, stable long-term physical properties, and process stability that do not occur in lab-scale approaches. Therefore, for industrially manufacturing high-quality fibers or spunbonds, a controlled rheology strategy for the pilot-scale production of PP should be established. In this study, a pilot-scale extrusion process and controlled rheology were combined to account for structural and rheological changes in PP by controlling the peroxide content and processing conditions such as the screw speed and extrusion temperature. Two types of pilot-scale (mild and harsh) twin-screw configurations with an L/D exceeding 40 were adopted. Furthermore, the peroxide remaining inside the extruder after extrusion was considered while changing the extrusion temperature and screw speed. CR-PPs can be stabilized by changing the temperature and pressure inside the extruder and by verifying the MI value. Finally, the applicability of CR-PPs in the melt-spinning process was substantiated by comparing the melt tension and draw resonance instability occurring in the spinline with those of PPs commercialized for staple fibers.Two pilot-scale twin-screw extruders with different screw configurations were incorporated to realize peroxide-initiated reactions during PP extrusion through the sequential steps of conveying, melting, mixing, and homogeneous discharging. The twin screws present full intermeshing and co-rotating features but exhibit different shapes and configurations in terms of their elements. Detailed structural specifications of the twin screws are shown in In the extrusion processing of PP polymers through mild and harsh twin-screw configurations, three process parameters  were mainly changed in the consideration of PP intrinsic properties to manufacture extruded CR-PPs. The screw speed was set to 200 and 250 rpm and a vacuum pump was installed in the extruder to remove volatile materials. The PP extrudate strands at the die exit were cooled rapidly in a long water bath and pelletized. Peroxides from 0 to 600 ppm were mixed with the PP resin before extrusion. The temperature in each screw zone specified in For reactive extrusion experiments based on controlled rheology, neat PP with an MI of 4 manufactured by S-Oil  = 0.743 g/mL, number-average molecular weight  was compared with other homo PP resins commercialized for staple fiber application. Three commercial homo PPs with an MI of approximately 15 were obtained from S-Oil  in the cone-and-plate with a diameter of 25 mm and cone angle of 0.1 rad. A frequency sweep test was performed in the frequency range of 0.1 to 300 rad/s at a constant strain of 5%. Disk-shaped PP specimens with a diameter of 25 mm were prepared using a mold to analyze the rheological properties. The mold was heated to 230 °C under a pressure of 5 MPa using a hot press .For the fiber-spinning application of homo PPs  and CR-PP (with a peroxide content of 200 ppm) for staple fiber production, their rheological properties were measured at 180 °C using MCR-302  under the abovementioned frequency-sweep mode to be correlated with the melt tension data presented in CR-PP samples for measuring various mechanical properties were manufactured using a family mold in a 130-ton injection machine . All samples were aged at room temperature and 50 RH% for 48 h prior to performing the following measurements: MI (ASTM D 1238) at 230 °C and a piston weight of 2.16 kg, tensile strength (ASTM D 638) under 50 mm/min (speed of testing), flexural modulus (ASTM D 790) under 2.5 mm/min (rate of crosshead motion), and Izod impact strength (ASTM D 256) under a 3 J pendulum.FT-IR  was performed to determine the degree of peroxy-promoted oxidation inside CR-PPs. The transmission mode was used in a disk-type PP specimen measuring 10 mm in diameter and 0.2 mm thick prepared using a hot press  at 230 °C. A CXS (ISO 16152:2005) test was conducted to qualitatively estimate the crystallinity of CR-PPs treated with different peroxide contents. Amorphous atactic parts in PP resin were dissolved in hot xylene liquid (135 °C) under a nitrogen environment and cooled to 20 °C. After filtration through a filter paper, the weight of the remaining crystalline components was measured. The weights of the CR-PPs before and after thermal annealing were measured using an electronic scale  to determine the change in the amount of volatile materials  inside the sample. The CR-PPs were annealed in an oven at 130 °C for 3 h.The applicability of peroxide-treated CR-PP (with 200 ppm peroxide) to the fiber-spinning process , which iNote that most experiments were repeated three or more times to obtain reliable data.Extrusion conditions such as the twin-screw configuration, extruder temperature, and screw speed can significantly affect the chain scission of PP by peroxide inside the twin-screw extruder. First, the effect of peroxide content on various properties  of PP (HD500) was examined using pilot-scale twin-screw extruders with mild and harsh screw configurations at an extrusion set temperature of 200 °C and screw speed of 200 rpm . Other eAs the chain scission reaction by peroxide proceeded in the twin-screw extrusion process, the MWD, a key factor in chain length uniformity, varied accordingly. The MWD narrowed gradually as the peroxide content increased b, which −1 for C = C bonds [Because the amorphous atactic component of semi-crystalline PP dissolved in xylene, the effect of the peroxide content on the xylene-soluble feature in CR-PPs was interpreted as shown in  C bonds  increaseThe melt rheological properties of neat PP (HD500) and its CR-PPs treated with different amounts of peroxide, i.e., their complex viscosity as well as storage and loss moduli data, were measured at 200 °C . SamplesA comparison of the various mechanical properties of neat PP and CR-PPs treated with different peroxide contents is shown in During the continuous pilot-scale reactive extrusion of PP, residues inside the extruder can affect subsequent products containing different peroxide contents. When the peroxide content for CR-PP production was changed stepwise from 0 to 600 ppm (and from 600 ppm to 0) in the hopper during the continuous harsh twin-screw extrusion under 200 and 250 rpm conditions and a temperature of 215 °C, the MI of the CR-PP extrudates changed gradually during the transit period, based on the residence time of melt polymers traveling between twin-screws inside the extruder . After cAdditionally, changes in the temperature and pressure at the die were monitored in real time after changing the peroxide content in the hopper or screw speed  at an exThe emission of volatile materials, such as low-carbon hydrocarbons, inside reactive-extruded thermoplastic polymers depends on the chemical structures of the polymers and the processing conditions. Based on issues pertaining to environmental regulations and the operating situations, the amounts of volatile materials inside CR-PP samples extruded via mild and harsh twin-screw extruders at different extrusion temperatures  and screw speed (200 and 250 rpm) were measured using the experimental method presented in As illustrated in By employing the lab-scale single-screw extruder and Rheotens equipment, CR200 and three homo PPs were applied to the fiber-spinning process. In the Rheotens test, melt tension was defined as the force to draw the melt strand in the spinline from the spinneret to the take-up roll, and it can be expressed as a function of the take-up velocity. Melt tensions for PPs were measured in the Rheotens by gradually increasing the take-up speed (or drawdown ratio). The extrusion temperature was set at 180 °C. As shown in Above the critical take-up speed (or drawdown ratio), draw resonance instability occurs in the spinline, exhibiting periodic variations in the melt tension and spinline diameter, which is detrimental to the production of uniform fiber products. Based on the melt tension data and direct observation of the variation in the spinline diameter along the take-up speed, draw resonance onsets for the PP samples were determined by changing the extrusion rate, as shown in Controlled rheology is a useful method for generating more uniform polymer chains via the addition of peroxides during reactive extrusion. In this study, the role of peroxide content in altering the structural and rheological properties of CR-PPs was investigated via chain scission reactions inside pilot-scale twin-screw extruders. Small amounts of peroxide up to 600 ppm effectively increased the MI, thereby narrowing the MWD of CR-PPs. The chain cleavage of PP by peroxide increased the amount of atactic moieties, which prevented crystallization via the formation of unsaturated chain ends such as C = C. The effect of extrusion conditions, such as the screw configuration, extruder temperature, and screw speed, on the properties of CR-PPs was examined. At extrusion temperatures above 215 °C, the harsh twin-screw extruder, which provided a high shear force, indicated a distinct peroxide effect as compared with the mild twin screw extruder. By considering the residence time variation of the peroxide remaining inside the extruder, it was confirmed that the extrusion process stably reached a new steady state within a few minutes, based on the stepwise change of the input materials with different peroxide contents. Meanwhile, by comparing the melt tension exerting on the spinline and the onset of draw resonance instability in the melt-spinning process for CR-PP and three commercially available homo PPs, it was discovered that CR-PP with a relatively lower elasticity and higher melt tension provided a more stable spinnability region in the melt-spinning process. Hence, CR-PPs with target-oriented properties are industrially suitable for producing uniform staple fibers and spunbonds through high-speed spinning processes.


Siboglinum fiordicum in laboratory conditions outside the marine environment for 64 days.The article describes the parameters of maintaining the gutless symbiotrophic annelid  Siboglinidae Caullery, 1914 is a family of marine annelids, which are all devoid of a digestive tract. Their nutrition is derived from symbiotic bacteria, which inhabit a special organ known as the trophosome. Frenulate pogonophorans  are the largest group of the family and are widespread in all oceans of the globe. Frenulate pogonophorans are slender worms and live in chitin tubes embedded in soft deposits. Symbionts of certain frenulate pogonophorans are capable of oxidizing hydrogen sulfide or methane . FrenulaSiboglinum fiordicum Webb, 1963 worms and mud samples were collected with a Van Veen grab sampler (0.25 m2) from a depth of 33–35 m near the Øpsesundet Strait  in the North Sea from February 7 to February 15, 2022. Alive pogonophorans were placed in 50-mL tubes and transported in 2-L insulated flasks  with cooling agents. The worms were delivered to Moscow February 18, 2022 and placed in a specially designed aquarium at the Invertebrate Zoology Department (Moscow State University) February 22, 2022.Bottom water samples to be tested for dissolved oxygen concentration and pH were collected with a Ruttner water sampler (KC Denmark A/S) in the the Øpsesundet Strait. Oxygen was measured by the Winkler method ; the temOur experimental device was based on a 140-L aquarium (80 × 50 × 35 cm). Water was prepared using a Geizer-prestizh 2 reverse osmosis system (Russia) with a ULP1812/2012 membrane  and a Spectrum SRDI Ion Exchange Resins (United Kingdom). Marine water with a salinity of 33‰ was prepared using Coral Pro salt . Fine-pore filter foam sheets were placed in two sections of the aquarium to ensure mechanical filtration and precipitation of stirred sediment. A constant temperature of 6–8°C was maintained using a Mini 600 aquarium chiller . The conditions were continuously monitored and the oxygen concentration and pH were regulated using a WTW DIQ/S 282 two-channel industrial controller  with a SensoLyt® SEA pH electrode  and a FDO®700 IQ SW optical sensor for dissolved oxygen . A controller of a G7J electromagnetic valve  turned on a carbon dioxide inflow when pH exceeded 7.6. A general scheme of the device is shown in S. fiordicum worms were transferred into the aquarium. The worms were placed in plastic tubes with an inner diameter of 7 or 8 mm and a length of 10–15 cm. The lower end of a tube was closed with 100-µm bolting cloth, and holes of 2 mm in diameter were drilled in the walls at intervals of 1.5–2 cm. The holes ensured that water and sediment particles enter the tube. Plastic tubes with worms were placed in glass tanks (0.5–2 L), which were partly filled with sediment  to April 26, 2022 (checkup). To evaluate the worm condition, worms were extracted from their plastic tubes April 26, 2022 and examined under a stereoscopic microscope. The worm condition was evaluated by worm mobility within the chitin tube, the integrity of the anterior and posterior ends, the presence of the anterior tentacle, and the natural reddish body color. S. fiordicum culture in laboratory conditions, which were as close as possible to the environmental conditions at the site of worm collection.Sediment to place the worms in the aquarium was collected together with worms in the Øpsesundet Strait and transported in 0.5- and 2-L plastic containers. The Siboglinumfiordicum live in relatively long (up to 243 mm) and very thin (0.2–0.3 mm in diameter) tubes. The tubes were bent when sediment was collected with a grab sampler and during extraction of worms from sediment. Damage to soft tissues of worms was caused by tube bending and might remain undetected upon visual examination. More delicate procedures of worm collection and transportation should be developed to successfully culture S. fiordicum.Three worms were found to be in good condition after being kept in the aquarium for 64 days. The results showed that frenulate pogonophores are possible to keep in laboratory conditions similar to those of their natural habitat for more than 2 months. A low survival of worms in laboratory conditions was possibly associated with a traumatic mode of worm sampling.


Marginal ice zones (MIZs) are qualitatively distinct sea-ice-covered areas that play a critical role in the interaction between the polar oceans and the broader Earth system. MIZ regions have high spatial and temporal variability in oceanic, atmospheric and ecological conditions. The salient qualitative feature of MIZs is their composition as a mosaic of individual floes that range in horizontal extent from centimetres to tens of kilometres. Thus the floe size distribution (FSD) can be used to quantitatively identify and describe them. Here, the history of FSD observations and theory, and the processes (particularly the impact of ocean waves) that determine floe sizes and size distribution, are reviewed. Coupled wave-FSD feedbacks are explored using a stochastic model for thermodynamic wave-sea-ice interactions in the MIZ, and some of the key open questions in this rapidly growing field are discussed.This article is part of the theme issue ‘Theory, modelling and observations of marginal ice zone dynamics: multidisciplinary perspectives and outlooks’. One of the most-studied feedbacks is related to wave-induced fracture, summarized in The positive side of this feedback process (4P) has been an area of research because outside of winter months sea ice in the MIZ is often in a state of melting. Thus waves can trigger local sea-ice-albedo feedbacks ,83,84. T (a)Floe size variability can dramatically affect the way sea ice evolves as a thermodynamic medium, by preconditioning or increasing its susceptibility to melt, especially in concert with wave-derived fragmentation. For example, as explored in ,84, a suConsider a highly simplified sea ice region with an area fraction A common definition of ace area , which crea [H0)  as5.6β=Equation  is intega  shows curves of sea ice volume obtained by integrating forward equation (c then scatters the day where that occurs as a function of floe size. The black line on (c) highlights a period of 180 days, which here approximately marks the duration of an entire melt season. Thus the difference between having small floes (as in the MIZ) or larger ones (as in the pack ice) can determine whether sea ice is melted over a seasonal cycle—from 1 m to 1 km, the time to melt sea ice is altered from 90 to 230 days. Integrations with large floes may sustain sea ice throughout the entire melt period. Such impacts have been observed in model studies: in simply varying floe sizes across an order of magnitude [Figure 3equation . Reducinagnitude , in a moThe ‘direct’ influence of lateral melting takes place for relatively small floes in the MIZ. Yet size-dependent effects are found for much larger scales, in the form of ‘apparent’ lateral melting via oceanic processes at the boundaries of floes hundreds of metres and larger. Because of on–off differences in solar forcing across a sea ice edge Floe size plays an important role in the propagation of ocean surface waves. Two main classes of approaches to wave-sea-ice impacts exist: those that treat sea ice as a viscous layer, and those that treat sea ice as a composite scatterer ,94. The in situ, but an examination of the seasonal variability of, for example, the MIZ width determined by floe sizes is a potentially motivating area for future work. Aspects of direct wave-sea-ice coupling are discussed in a number of articles in this issue [A number of different models have been employed to understand the way fractured floes affect wave attenuation. In general, these smaller floes attenuate less wave energy than larger ones, at both small and large wavelengths . Thus this issue ,76,94. (c)As discussed in equation . Each in used in . The frab—the impact of waves is a significant increase in the lateral melt rate of the sea ice in total. The same melt-period diagnostic based on these wave simulations is added in figure 4c, which shows that across the range of initial floe sizes, there is a significant decline in the period of sea ice melting. The solid curve plots the difference between the wave-free and ensemble-mean wave-influenced time to melt sea ice, which can be as high as 70 days for floes with an average size around 100 m. Figure 4d plots the relative increase in heat Sea ice is a two-dimensional granular material. This means that the floe size plays the role of the grain size in standard granular theory . A serieMore highly broken floes permit higher contact between the ice and the ocean, by the simple fact that they move independently, revealing small patches of open water. These small regions reduce total sea ice concentration and permit more sunlight. More floe-like systems, for example, in the Southern Ocean, may permit significant amounts of sunlight to reach through them in summer. This in turn could seed phytoplankton blooms underneath sea ice . Indeed,. 6Leveraging a litany of recent efforts to understand how floes influence sea ice and its role in the Earth system, many areas exist for further research into MIZs and the floes that comprise them. There remain limited high-temporal-resolution observations of FSD evolution, particularly when impacted by waves or under stress. Climate models are now only beginning to be able to evolve coupled wave-ice feedbacks, and remain far from able to resolve eddy processes influenced by and driving differential sea ice motion at the scale of floes. The potential impact of both positive and negative feedbacks related to sea ice floe evolution remain an under-explored topic with potentially high relevance as more of the Arctic becomes seasonally ice-free. There is much to be excited about as this field continues to grow and evolve.


This study aimed to explore relationships between fitness, on-ice physical abilities and game performance among elite junior male ice hockey players. Twenty-one major junior ice hockey players (18.9 ± 1.4 years old) participated in the study. Measures including five fitness tests  and three on-ice skating tests  were assessed during their pre-season training camp. Game performance metrics (collected during the regular season) were collected using InStat software. Results of the (on-ice and off-ice) functional performance test protocol and on-ice tests were analyzed by evaluating correlation coefficients in multiple areas of game performance: 1) physical implication (body checks), 2) offensive contribution , and 3) defensive actions . They revealed that performance in the broad jump test was associated with skating speed. Some significant correlations were also observed between on-ice test performance indicators such as received body checks, expected goals and blocked shots. In summary, results indicate that on-ice test protocols were associated with players’ performance in multiple aspects of the game. Partial correlation analyses revealed that some of these relationships were specific to the player's position. Forward skating was associated with forwards’ offensive play, and backward skating was specifically related with defensemen’s performance (offense and defense). The addition of on-ice physical tests appears essential for interpreting the results of ice hockey players' physical tests and integrating these results into players’ physical preparation and the in-season follow-up. Ice hockey comprises high-intensity actions that require players to perform at technical and tactical levels. Such demands become a challenge for coaches and strength and conditioning trainers, who must ensure that their athletes stay at the top of their game while respecting their ability to adapt to the demands of a season . RigorouSome authors also paid attention to variables such as the workload and volume over a season. Results from their work showed some fluctuations during a season . Modern We believed that results from fitness testing protocols can explain game performance in elite ice hockey. In this regard, this study had three objectives: 1) to analyze relationships between off-ice functional performance fitness tests and on-ice tests, 2) to verify whether players’ fitness measured in off-ice and on-ice was associated with their game performance success, and 3) to verify whether the relationships differed based on the players’ position. An improved understanding of these associations will help strength and conditioning coaches prepare athletes more efficiently and work in collaboration with coaching staffs.The study sample consisted of twenty-one elite junior players that evolved in the Quebec major Junior Hockey League (QJMHL), one of the three major junior hockey leagues that make up the Canadian Hockey League (CHL), which is among Canada’s best junior leagues. Players came from one team, since our particular aim was to assess their performance in a regular season. Players who took part in the study  were between 17 and 21 years of age (18.9 ± 1.4 years). Goaltenders were excluded from the study owing to the small sample size and their task-specific characteristics. Players who agreed to participate in the study signed an informed consent form, approved by the researchers’ institution ethics board (CER-20-271-07.05). Participants completed a battery of functional performance tests at a training camp prior to the 2019-2020 season. Testing sessions were conducted on two consecutive days: 1) Day 1: anthropometric measures and functional performance off-ice, and 2) Day 2: on-ice skating tests.Upper body strength. We measured upper body strength-endurance using two tests: 1) the bench press test, 2) the pull-up test. Each participant had to perform the maximal number of repetitions on a bench press, using an Olympic barbell (20 kg) plus 75% of their body weight. The bench press test protocol1 was validated beforehand . Participants were required to hold the overhead bar with a pronated grip, hands approximately shoulder-width and arms extended. Participants rose by bending their arms until the chin was above the top of the bar, then lowered themselves to the starting position. Only the number of repetitions performed with the correct technique was counted.Lower Body Muscular Power. We assessed muscular leg power using two tests: 1) the broad jump  and 2) the vertical jump . Sprint tests in skating were inspired from the International Ice Hockey Federation (IIHF) Skills Challenge Manual tests . A modified version was used for assessing speed in a forward and a backward sprint test over a distance of 30.48 m, with the acceleration time recorded at 0 to 7.65 m. The participant started on the ice at the goal line and was required to cover the distance as fast as possible. Time splits were measured and recorded with the Brower timing system, with photocells fixed at a height of 1 m.Aerobic Capacity. The aerobic capacity was measured with the Multi-Stage Aerobic Test for Skating (SMAT) (2max was estimated based on the last completed stage.g (SMAT) , 2019. Ihttps://instatsport.com/hockey/instat_scout) which had performance markers computed from the InStat video database. Data covered the full 2019-2020 season, in which the Quebec major Hockey League (QJMHL) played 64 regular season games . Possession metrics such as controlled entries  and controlled zone exits  were also considered because of their association with the team’s offensive performance. Defensive contribution was assessed using two indicators, i.e., blocked shots and defensive expected goals, which is the opponent’s expected goals statistic when a specific player is on the ice.Players’ game performance was measured by choosing indicators that were collected with the InStat analysis tool (p > .05). For objectives 1 and 2, we analyzed correlations between off-ice and on-ice tests (O1) and those involving on-ice fitness and game performance (O2). For objective 3, we controlled for the effect for the players’ position (forward versus defenseman) by analyzing partial correlation coefficients on correlations that were previously obtained. Analyses were performed using SPSS software (version 27), with the level of significance set at p < .05.Results for off-ice and on-ice fitness were analyzed using descriptive statistics. Means and standard deviations of all variables were calculated and assumptions of normality of the distributions were tested using the Shapiro-Wilk (SW) test. No violations of normality were observed . For on-ice tests, we observed that defensemen were better in both backward skating tests  and forwards had higher VO2max values .Descriptive characteristics are presented in r = -.536; p < 0.05) and the backward skating test . As illustrated in rpartial = -.717, p = .003). Furthermore, weight correlated with both backward skating tests . Partial correlation analyses revealed that this association was significant for forwards and defensemen .Correlation matrices are available in Appendix A and B. Two off-ice variables tended to be associated with on-ice physical tests. The broad jump was correlated with the forward skating test . Partial correlation showed that these associations remained significant even after controlling for the players’ position .We observed only one significant association between off-ice tests and game performance. The only significant association between functional performance and match performance was the association between the vertical jump, and the number of given body checks . Inversely, they tended to give more body checks to opponents, yet this association was not significant . When we controlled for the position, partial correlations remained significant , which means that faster players were involved in play and received more hits, regardless of whether they were forwards or defensemen. In r = -.485, p < .05). However, the non-significant partial correlation coefficient  shows that this association was specific to forwards.r = -.528, p < .05). This association remained significant when controlling for the players’ position , suggesting that faster skaters tended to contribute offensively for either defensemen or forwards. The results presented in r = -.497, p < .05). When we analyzed partial correlations to control for the players’ position, the coefficient was non-significant  suggesting that such association was specific to defensemen only.As with forward skating, Preparing hockey players to perform in competition operates through a precise evaluation of their physical abilities. Therefore, we can hypothesize that the fitter the players are, the better they will perform on the ice. In this regard, a wealth of scientific literature documents ice hockey players’ abilities in terms of functional performance and the on-ice performance profile. Despite these contributions, very few authors have studied the relationships between players’ test results and their performance in real game situations. This study offers a new perspective by analyzing results obtained in functional performance tests and their relationships with game performance metrics collected with modern technology.In line with previous research, our results showed few significant relationships between office fitness and on-ice performance. Two off-ice fitness tests were related to on-ice performance. Results of the broad jump test were significantly correlated with on-ice skating sprint tests, which supports the predictive validity of the broad jump for determining skating speed. Such results are in line with the findings of As mentioned earlier, there are only few studies that demonstrate strong associations between players’ fitness and their responses in game performance. Consideration of performance indicators that are closely related with corresponding physical attributes seems a way to develop stronger evidence regarding such associations. Our results are congruent with this hypothesis and indicate some positive associations in which physical attributes measured in different contexts  tend to be related to game performance. First, we observed that performance in the vertical jump was associated with our measures of physical implication in the game , suggesting that more powerful players tend to be more physically involved in the game. Although this relationship appears plausible, no other research reveals such findings. In contrast with the conclusions of Secondly, analyses performed with our sample support the relevance of including on-ice tests. Our results revealed that skating speed appeared to be a factor associated with players’ physical implication in the game. In addition, greater speed also resulted in a higher risk of being hit by opponents. While this looks surprising at first, it seems realistic that slower players are less likely to be checked, since they may be less involved in the game. In contrast, a faster player is more likely to carry the puck and get to the puck first in loose puck situations, making him/her more vulnerable to being checked by the opponent. Our results also show that faster skaters (in the forward sprint) tend to generate a higher offensive contribution measured as expected goals. Expected goals (xGs) reflect offensive production and are calculated from the relative contribution of different factors, which allows for calculating the player’s scoring probabilities. We have to specify that xGs are assessed in different ways depending on multiple factors . In the present study, we used the InStat model which has its own algorithm for calculating xGs. At first, our findings appear to contradict those of Williams (2019) who did not report associations between American college players’ physical attributes on their overall point-share value. It should be noted, however, that the point-share indicator used by Williams (2019) may have been an insufficient indicator. Likewise of interest are the significant associations between the speed of backward skating and the offensive  and defensive actions  of defensemen. Even though Despite its contribution, this study has some limitations. The sample size is small and even if a sufficient level of statistical power was attained, generalization of our results is limited. Considering one team only (single cohort) may lead to possible bias. For example, the approach involving testing and physical preparation valued by the team under study can relate to players’ responses in fitness and on-ice testing. Better performing players may, in consequence, be evaluated as “best prospects”, leading to more favorable player’s utilization throughout the season. The use of more teams in a research design of this kind would enable a deeper understanding of the associations between the physical attributes assessed and their relationship to game performance. In the longer term, it seems essential to replicate the present protocol with larger samples and even different levels of play. Indeed, it is certain that the results of this study can serve as a baseline for future research.The second limitation involves the selected performance indicators which were based on our expertise in ice hockey, the rationale supported in the scientific literature and data availability from InStat technology. In our opinion, additional indicators  could have been useful for establishing stronger links between players’ physical attributes and their game performance. These objective indicators could serve as additional relevant variables in future research and enable the holistic analysis of physiological demands with game performance.The third limitation resides in the on-ice tests selected and their potential association with game-specific indicators. In this regard, even if skating speed is important, assets such as skating agility and ability to repeat sprints are key on-ice components that need to be assessed. Measuring these kinds of assets may plausibly lead to important associations with specific aspects of the game. From this perspective, we think that measuring agility (and its related indicators) could reinforce the associations between testing and game performance. As shown by Finally, we believe that the cross-sectional nature (and the time span between players’ testing and the regular season) of the design has its share of limitations as well. Consideration of the statistics covering a full season without taking into account possible fluctuations in players’ performance throughout the season  could lead to weaker correlation coefficients. A decrease in physical performance over the course of a full hockey season has been observed among junior and collegiate players in the CHL . This phAn improved understanding of the relationship between ice hockey players’ off-ice physical abilities and their performance in game situations allows strength and conditioning coaches to develop better training plans and adapt testing methods to ensure that players receive optimal preparation. This study provides some answers especially for choosing tests to prioritize when aiming for peak performance. From this perspective, the long jump test is of first importance because it is associated with the on-ice skills linked with players' offensive play. The addition of on-ice tests makes it possible to bridge the gap between players’ physical fitness and skills and game performance. This study also offers potential further developments. Knowing that some physical attributes are related with game performance, it becomes clearer for strength and conditioning coaches to prioritize which fitness components to train throughout the in (and off) season. From this perspective, approaches based on the specificity of movement  such as agility training and multiple changes of direction are promising and seem to provide additional benefits . In this regard, on-ice conditioning seems to be a promising approach for junior elite players who spend large amounts of time on the ice. Off the ice, other approaches also have their potential to enhance players’ predisposition to perform. Some interesting examples prevail in emerging approaches such as post-activation potentiation  and resiIn summary, including an on-ice physical test in a battery of physical tests to evaluate fitness of ice hockey players is useful, given this test’s potential transferability to game performance. According to our results, strength and conditioning coaches should include on-ice training in their training plans to increase their players’ response to game-specific tasks.