Case report: Echocardiographic and computed tomographic features of congenital bronchoesophageal artery hypertrophy and fistula in a dog.

Introduction: Studies on aberrant bronchoesophageal arteries are limited. Herein, we report a case of a multi-origin systemic-to-pulmonary shunt with suspected bronchoesophageal artery hypertrophy and fistula in a dog. Case report: A 4-year-old castrated male beagle weighing 11 kg underwent routine medical screening. Physical examination revealed a right-sided continuous murmur of grades 1-2. Thoracic radiography revealed a mild cardiomegaly. Echocardiography revealed a continuous turbulent shunt flow distal to the right pulmonary artery (RPA) branch from the right parasternal short axis pulmonary artery view. Computed tomography demonstrated systemic-to-pulmonary shunts originating from the descending aorta at the level of T7-8, the right 5th and 6th dorsal intercostal arteries, and the right brachiocephalic trunk, which formed anomalous networks around the trachea and esophagus that anastomosed into a large tortuous vessel at the level of T6-7 and entered the RPA. Surgical ligation of multiple shunting vessels was performed. Postoperative echocardiography and computed tomography showed decreased left ventricular volume overload and markedly decreased size of the varices. Additionally, most of the shunting vessels were without residual shunt flow. Conclusion: The present study provides information regarding imaging features and the successful surgical management of multiple systemic-to-pulmonary shunts originating from the descending aorta, right brachiocephalic trunk, and intercostal arteries and terminating at the RPA. Multimodal imaging features after surgical ligation have also been described.

Tailoring Contacts for High-Performance 1D Ta2Pt3S8 Field-Effect Transistors.

Materials with van der Waals (vdW) unit structures rely on weak interunit vdW forces, facilitating physical separation and advancing nanomaterial research with remarkable electrical properties. Recently, there has been growing interest in one-dimensional (1D) vdW materials, celebrated for their advantageous properties, characterized by reduced dimensionality and the absence of dangling bonds. In this context, we synthesize Ta2Pt3S8, a 1D vdW material, and assess its suitability for field-effect transistor (FET) applications. Spectroscopic analysis and electrical characterization confirmed that the band gap and work function of Ta2Pt3S8 are 1.18 and 4.77 eV, respectively. Leveraging various electrode materials, we fabricated n-type FETs based on Ta2Pt3S8 and identified Cr as the optimal electrode, exhibiting a high mobility of 57 cm2 V-1 s-1. In addition, we analyzed the electron transport mechanism in n-type FETs by investigating Schottky barrier height, Schottky barrier tunneling width, and contact resistance. Furthermore, we successfully fabricated p-type operating Ta2Pt3S8 FETs using a molybdenum trioxide (MoO3) layer as a high work function contact electrode. Finally, we achieved Ta2Pt3S8 nanowire rectifying diodes by creating a p-n junction with asymmetric contact electrodes of Cr and MoO3, demonstrating an ideality factor of 1.06. These findings highlight the electronic properties of Ta2Pt3S8, positioning it as a promising 1D vdW material for future nanoelectronics and functional vdW-based device applications.

Whole Blood Viscosity Reference Intervals and Its Correlation with Hematology and Serum Chemistry in Cats Using Scanning Capillary Method.

Whole blood viscosity, a hemorheological factor, is currently used for diagnosis, as it is correlated with various vascular diseases that are difficult to diagnose early with a general blood test. It was determined that it was necessary to set reference intervals for further studies and utilization of whole blood viscosity in cats, a representative companion animal, and this study was conducted. Fifty healthy cats were recruited for the study, and whole blood viscosity, complete blood count, and serum chemistry tests were performed. The reference intervals of whole blood viscosity were 15.169 to 43.684 cP at a shear rate of 1 s-1 reflecting diastole, and 3.524 to 5.544 cP at a shear rate of 300 s-1 reflecting systole. Red blood cells, hematocrit, hemoglobin, white blood cells, and neutrophils in the complete blood count, and total protein, albumin, globulin, and cholesterol in the serum chemistry were significantly correlated with whole blood viscosity. The results of this study set the reference intervals of whole blood viscosity for healthy cats in a wide shear rate range that has not yet been fully established, and its correlation with other blood indicators investigated.

Colloidal Synthesis of Ultrathin and Se-Rich V2Se9 Nanobelts as High-Performance Anode Materials for Li-Ion Batteries.

In this study, the one-dimensional (1D) material V2Se9 was successfully synthesized using a colloidal method with VO(acac)2 and Se powder as precursors in a 1-octadecene solvent. The obtained colloidally synthesized V2Se9 (C-V2Se9) has an ultrathin nanobelt shape and a 4.5 times higher surface area compared with the bulk V2Se9, which is synthesized in a solid-state reaction as previously reported. In addition, all surfaces of C-V2Se9 are exposed to Se atoms, which is advantageous for storing Li through the conversion reaction into the Li2Se phase. Herein, the electrochemical performance of the C-V2Se9 anode material is evaluated; thus, the novelty of C-V2Se9 as a Se-rich 1D anode material is verified. The C-V2Se9 electrode exhibits a reversible capacity of 893.21 mA h g-1 and a Coulombic efficiency of 97.82% at the 100th cycle and excellent structural stability. Compared with the bulk V2Se9 electrode, the outstanding electrochemical performance of C-V2Se9 is attributed to its ultrathin nanobelt shape, high surface area, shorter Li diffusion length, and more electrochemically active sites. This work indicates the great potential of the Se-rich 1D material, C-V2Se9, as a post-transition metal dichalcogenide material for high-performance LIBs.

Fabrication of a Field-Effect Transistor Based on 2D Novel Ternary Chalcogenide PdPS.

Two-dimensional (2D) palladium phosphide sulfide (PdPS) has garnered significant attention, owing to its exotic physical properties originating from the distinct Cairo pentagonal tiling topology. Nevertheless, the properties of PdPS remain unexplored, especially for electronic devices. In this study, we introduce the thickness-dependent electrical characteristics of PdPS flakes into fabricated field-effect transistors (FETs). The broad thickness variation of the PdPS flakes, ranging from 0.7-306 nm, is prepared by mechanical exfoliation, utilizing large bulk crystals synthesized via chemical vapor transport. We evaluate this variation and confirm a high electron mobility of 14.4 cm2 V-1 s-1 and Ion/Ioff > 107. Furthermore, the 6.8 nm-thick PdPS FET demonstrates a negligible Schottky barrier height at the gold electrode contact, as evidenced by the measurement of the temperature-dependent transfer characteristics. Consequently, we adjusted the Fowler-Nordheim tunneling mechanism to elucidate the charge-transport mechanism, revealing a modulated mobility variation from 14.4 to 41.2 cm2 V-1 s-1 with an increase in the drain voltage from 1 to 5 V. The present findings can broaden the understanding of the unique properties of PdPS, highlighting its potential as a 2D ternary chalcogenide in future electronic device applications.

Comparison of patellofemoral contact pressure after semi-cylindrical recession trochleoplasty and trochlear block recession in feline cadavers.

Introduction: The purpose of this study was to compare the changes in the patellofemoral joint (PFJ) contact mechanisms of the normal state, trochlear hypoplasia model and after performing trochleoplasty on the hypoplasia model in feline cadavers. Methods: Twenty normal pelvic limbs were acquired from the 10 feline cadavers. First, the PFJ contact mechanisms were measured in normal state, then trochlear hypoplasia models were created using customized trochlear ridge cutting guides. After measuring PFJ contact mechanisms in the trochlear hypoplasia models, they were divided into two groups and performed semi-cylindrical recession trochleoplasty (SCRT) and trochlear block recession (TBR) were performed, respectively. After that, the PFJ contact mechanisms were measured and the values of the 4 groups (normal state, trochlear hypoplasia, SCRT, TBR) were compared. Results: The trochlear hypoplasia group showed increased contact pressure and decreased contact areas compared to the normal state group. In the groups that underwent tracheoplasty (SCRT and TBR), PFJ contact mechanisms were recovered similarly to that of the normal state group. The PFJ of the SCRP group was measured similar to that of the normal group than that of the TBR group. Discussion: Tracheoplasty can be useful in restoring PFJ contact mechanisms and SCRT can be considered as a good alternative to the conventional methods of trochleoplasty.

Ex Vivo Biomechanical Assessment of Various Repair Techniques in a Rabbit Calcaneal Tendon Avulsion Model: Application of Polycaprolactone Plate.

This study was aimed at evaluating the biomechanical properties and gapping characteristics of tendon repair methods using a combination of a three-loop pulley (3LP) pattern, a titanium plate, and a polycaprolactone (PCL) plate in a rabbit gastrocnemius tendon (GT) model (n = 50). GTs were randomly assigned to five groups (n = 10/group). Transected GTs were repaired with a 3LP pattern alone or in conjunction with an epitendinous suture (ES), a 5-hole 1 mm PCL plate, a 5-hole 2 mm PCL plate, or a 5-hole 1.5 mm titanium plate. The yield, peak, and failure force, as well as the occurrence and force of 1-mm and 3-mm gapping were examined. The mean yield, peak, and failure force of the 3LP + titanium plate group were higher than that of other groups. The biomechanical properties of a 3LP + a 2 mm PCL plate were similar to 3LP + ES constructs in this model. In all specimens in all groups, 1 mm gap formation was observed. The frequency of 3 mm gap formation was 70% and 90% in the 3LP + 2 mm PCL plate group and the 3LP + 1.5 mm titanium plate group, respectively. Additional studies evaluating PCL plates to determine the effect on the healing and blood supply of tendon are needed.

Accuracy of a 3-dimensionally printed custom endoscopy port for minimally invasive ventral slot decompression in dogs: A cadaveric study.

OBJECTIVE: To evaluate the accuracy of a 3-dimensionally (3D)-printed custom endoscopy port (3DEP) for minimally invasive cervical ventral slot decompression. STUDY DESIGN: Cadaveric study. ANIMALS: Fifteen cadavers of dogs weighing between 3.1 and 34.4 kg. METHODS: Minimally invasive cervical ventral slots were created using a 3DEP and an endoscopic system at the C3-C4 intervertebral disc space in each dog by 1 experienced and 1 inexperienced surgeon. Postoperative computed tomography was performed to compare the planned and postoperative screw trajectories (angle, entry point, exit point, and length of the screw entering the spinal canal) and quantify slot formation dimensions. RESULTS: Thirty screws were inserted in 30 vertebral bodies. Mean screw angle deviation was less than 2.5°, entry and exit point deviation was less than 1.6 mm, and length of the screw entering the spinal canal was less than 0.6 mm. No differences were identified between the experienced and inexperienced surgeons. Ventral slot length ratio was 30.15 ± 1.86 for the experienced surgeon and 29.38 ± 1.61 for the inexperienced surgeon (p = .372). The mean ventral slot width ratio was 45.60 ± 1.80 for the experienced surgeon and 47.20 ± 1.54 for the inexperienced surgeon (p = .261). CONCLUSION: Screw positioning and creation of ventral slots were accurately performed using the 3DEP by both inexperienced and experienced surgeons. CLINICAL SIGNIFICANCE: The use of a 3DEP for minimally invasive cervical ventral slot decompression may be an alternative to the conventional ventral slot in dogs. Additional studies are needed to evaluate efficacy and safety.

Comparison of dorsal and medial arthroscopic approach to canine coxofemoral joint: a cadaveric study.

BACKGROUND: Arthroscopic exploration of ventromedial part of canine coxofemoral joint is limited in conventional dorsal approach. OBJECTIVES: We evaluated the efficacy of a medial arthroscopic approach to the coxofemoral joint of dogs by analyzing the joint visible area and performing a safety analysis. METHODS: Arthroscopic approaches to the coxofemoral joint were made in five cadavers using a traditional (dorsal) and novel (medial) approach. Three observers scored the visible area of images and videos of the acetabulum and femur. A safety analysis was performed via dissection of the medial hind limb. The distance between neurovascular structures and arthroscopic portals was measured. RESULTS: The acetabulum was more visible in the dorsal than in the medial approach, with mean visualization scores of 16 ± 0.00 and 11.83 ± 1.26, respectively. The medioventral side of the femur was significantly more visible in the medial than in the dorsal approach, with mean visualization scores of 3.9 ± 0.99 and 6.93 ± 0.58, respectively. Safety analysis confirmed the medial portal site was safe, provided that the surgeon has comprehensive knowledge of the joint. The minimum distance from the arthroscopic medial portals to the nearest neurovascular structures was 2.5 mm. CONCLUSIONS: A medial arthroscopic approach to the canine coxofemoral joint has potential clinical application. Dorsal and medial approaches differ significantly and have distinct purposes. The medial approach is useful to access the ventromedial joint, making it an eligible diagnostic method for an arthroscopic evaluation of this area.

Colloidal synthesis of 1-D van der Waals material Nb2Se9: study of synergism of coordinating agent in a co-solvent system.

Low-dimensional Nb2Se9 nanocrystals were synthesised through a simple one-pot colloidal synthesis with C18 organic solvents (octadecane, oleylalcohol, octadecanethiol, octadecene (ODE), and oleylamine (OLA)) of varied terminal functional groups. The solvent with high reducing power facilitated the nucleation of the nanoparticle, lowering threshold concentration and broadening the concentration spectrum. As a solvent, reducing agent, and capping agent, ODE functions as a primary factor in the synthesis of high-quality Nb2Se9 nanorods. We further discuss the unique adhesion role of ODE under the co-solvent system and demonstrate morphology control through synergism between ODE and OLA, verified by the electrochemical measurements.

Case report: Reconstruction of a complex maxillofacial gunshot defect using a titanium patient-specific implant in a dog.

This report describes the surgical reconstruction of large maxillofacial defect caused by a short-range gunshot injury in a dog using titanium patient-specific implant (PSI). A 3-year-old male Wolf Shepherd was admitted for a large right facial defect with right nasal cavity exposure caused by a gunshot injury. Radiographic examination revealed severe loss of the right maxillary, nasal, and incisive bones, multiple fractures of both left and right palatine bones, and a comminuted fracture of the right mandible. Initial surgical procedure included computed tomography (CT) imaging for three-dimensional (3D) implant design. Open wound management was maintained for 18 days until the fresh granulation tissue fully covered the wound bed. The implant was designed in a "hand grasping shape" to cover the defect, align multiple fractured palatine bones, and make a snap fit function. Multiple holes, including cortical screw holes, were added to the final design. The implant was printed on a titanium alloy. Surgical application of titanium PSI was performed 19 days after the primary surgery. A free sublingual mucosal graft was used to reconstruct the mucosal layer of the right nasal cavity. The mucosa was then covered with collagen membrane to strengthen the structure of the nasal cavity. Blunt dissection of the hard palate mucoperiosteum above the palatine process and palatine bones, soft tissue above the maxilla was performed, and the 3D printed titanium implant was fastened in a preplanned position. The facial soft tissue defect was reconstructed, and the titanium PSI was covered using an angularis oris cutaneous flap. Partial flap necrosis occurred in the rostral aspect, and the wound was managed to heal by a second intension. Flap dehiscence at the junction of the flap and hard palate mucoperiosteum occurred with exposure of the implant 2 days postoperatively. Multiple attempts to close the defect failed, and the owner wanted to stop treatment. Healthy granulated tissue was observed proximal to the implant. The defect no longer increased in size and did not show any noticeable complications related to the defect at 60 days after titanium PSI application, and the dog was discharged. Six months post-operatively, the dog remained active with great appetite, gained weight, and showed acceptable facial symmetry without enlargement of the implant exposure or any implant-related problems.

Case report: Application of three-dimensional technologies for surgical treatment of portosystemic shunt with segmental caudal vena cava aplasia in two dogs.

This case report describes the application of three-dimensional (3D) technologies for the surgical treatment of portosystemic shunt (PSS) with segmental caudal vena cava (CVC) aplasia. Two client-owned dogs were diagnosed with PSS along with segmental CVC aplasia using computed tomography. Through 3D volume and surface rendering, the vascular anatomic anomaly of each patient was identified in detail. A patient-specific 3D vascular model was used for preoperative planning. According to the plan established based on the 3D rendered image and printed model, shunt occlusion was performed using cellophane banding in the first case. An ameroid constrictor was used in the second case. Both patients showed good recovery without any clinical symptoms or complications. The use of 3D technologies in small animals has many advantages, and its use in vascular surgery, as in these cases, is also a therapeutic option worth considering.

Accuracy of a patient-specific 3D-printed drill guide for placement of bicortical screws in atlantoaxial ventral stabilization in dogs.

Atlantoaxial instability (AAI) in dogs refers to abnormal motion at the C1-C2 articulation due to congenital or developmental anomalies. Surgical treatment options for AAI include dorsal and ventral stabilization techniques. Ventral stabilization techniques commonly utilize transarticular and vertebral body screws or pins. However, accurate screw insertion into the vertebrae of C1 and C2 is difficult because of the narrow safety corridors. This study included 10 mixed dogs, 1 Pomeranian, and 1 Shih-Tzu cadaver. All dogs weighed <10 kg. Each specimen was scanned using computed tomography (CT) from the head to the 7th cervical vertebrae. This study used 12 bone models and 6 patient-specific drill guides. Bone models were made using CT images and drill guides were created through a CAD (computer-aided design) program. A total of six cortical screws were used for each specimen. Two screws were placed at each of the C1, C2 cranial, and C2 caudal positions. Postoperative CT images of the cervical region were obtained. The degree of cortex breaching and angle and bicortical status of each screw was evaluated. The number of screws that did not penetrate the vertebral canal was higher in the guided group (33/36, 92%) than in the control group (20/36, 56%) (P = 0.003). The screw angles were more similar to the reference angle compared to the control group. The number of bicortically applied screws in the control group was 28/36 (78%) compared to 34/36 (94%) in the guided group. Differences between the preoperative plan and the length of the applied screw at the C1 and C2 caudal positions were determined by comparing the screw lengths in the guide group. The study results demonstrated that the use of a patient-specific 3D-printed drill guide for AAI ventral stabilization can improve the accuracy of the surgery. The use of rehearsal using bone models and a drilling guide may improve screw insertion accuracy.

Minimally invasive mini-hemilaminectomy-corpectomy in cadaveric dogs: evaluation of the accuracy and safety of a three-dimensionally printed patient-specific surgical guide.

BACKGROUND: As the frequency of spine surgery increases in the veterinary field, many studies have been conducted on minimally invasive spine surgery (MISS). Although many studies have been conducted on the thoracolumbar spine about MISS in animals, several problems and limitations have emerged regarding this method. Therefore, we developed a three-dimensional (3D) printed patient-specific surgical guide (3DPSSG) using 3D printing technology to overcome these problems. We aimed to evaluate the accuracy and safety of the 3DPSSG in minimally invasive mini-hemilaminectomy-corpectomy (MI-MHC). MI-MHC using 3DPSSG and an endoscopic system was performed at L1-L2 in 15 cadaveric dogs. The procedure of fixing the surgical guide to the vertebral body through screws and the surgical procedure using the guide were performed by two surgeons with different experiences. Postoperative computed tomography was used to measure planned and postoperative screw trajectories (angle, protruding from the far cortex) and to create 3D rendering images of vertebrae to evaluate the direction of bone window formation, corpectomy slot length, depth, and height ratio. RESULTS: The two groups which performed by two surgeons with different experiences did not differ in terms of screw angle deviation and length of the screw protruded from the far cortex. The corpectomy slot-length ratio was not different between the two groups; however, the slot-depth and height ratios were different. CONCLUSIONS: No differences were detected in screw trajectory and corpectomy slot-length ratio between the two groups. The 3DPSSG for MI-MHC is classified as accurate and safe; therefore, it can be an alternative to the conventional technique in dogs.

Evaluation of a customized 3D-printed saw guide for tibial plateau leveling osteotomy: An ex vivo study.

OBJECTIVE: To determine whether a tibial plateau leveling osteotomy (TPLO) performed with a customized 3D-printed guide and jig is more accurate than the traditional technique using a jig alone. STUDY DESIGN: In vitro study. SAMPLE POPULATION: Cadaveric canine pelvic limbs (n = 10) and 20 synthetic bone models. METHODS: Tibial plateau leveling osteotomy using a jig with (n = 10) and without (n = 10) a customized 3D-printed guide were performed in bone models, and TPLO using a jig with (n = 5) and without (n = 5) a customized 3D-printed guide were performed in cadaveric limbs. Angulation of the osteotomy, angulation of the proximal jig pin, angular/torsional deformity and medial cortex damage were measured from photographs of the specimens and compared. RESULTS: In the bone models, there were differences with and without the 3D guide for mean osteotomy inclination (-0.06° vs. -1.74°, P < .001), osteotomy torsion (5268 vs. 10 469 visible osteotomy pixels, P < .001), and medial cortical damage (2970 vs. 18 562 pixels, P < .001). In the cadaveric study, osteotomy inclination (-1.1° vs. 1.01°, P < .01), induced angular deformity (0.17° vs. -3.01°, P < .001) and angulation of the proximal jig pin (-0.27° vs. 0.80°, P < .001) differed between groups. CONCLUSION: The 3D-printed guide during TPLO resulted in slightly more accurate osteotomies and proximal jig pin placement, and reduced medial cortex damage. CLINICAL SIGNIFICANCE: A customized 3D-printed guide may improve intraoperative accuracy for TPLO, although the clinical significance of the small benefits is unknown.

Case Report: Imaging Features of Gallbladder Sessile Polyp Confirmed by Contrast-Enhanced Ultrasonography and Dynamic Computed Tomography in a Dog With Asymptomatic Chronic Cholecystitis.

A 6-year-old dog was presented for health screening. It never suffered from any disease. Ultrasonography confirmed mass-like thickening with irregular margins protruding toward the gallbladder (GB) lumen. On contrast-enhanced ultrasonography (CEUS) and dynamic computed tomography (CT), contrast enhancement of the corresponding structures was confirmed in arterial phase. After cholecystectomy, cauliflower-like sessile polyps were identified. Histopathological examination revealed chronic lymphoplasmacytic cholecystitis. Bile culture revealed Escherichia coli growth. Our novel findings suggest that chronic cholecystitis should be considered as a differential diagnosis if contrast-enhanced sessile polyps of the GB are found on CEUS and dynamic CT.

Evaluation of a screw insertion landmark for a minimally invasive repair technique in induced bilateral sacroiliac luxation in feline cadavers.

OBJECTIVES: The aim of this study was to describe an alternative landmark for screw insertion into the body of the ilium with bilateral sacroiliac luxation in cats. METHODS: Seven cat cadavers with artificially induced bilateral sacroiliac luxation were used. The screw insertion point was determined using the caudal iliac crest and cranial acetabular rim. These two points make the first guideline; a second guideline ran perpendicular to the caudal iliac crest point. The screw insertion point was halfway along the second guideline across the ilium body. Surgery was performed in a minimally invasive manner using fluoroscopy. RESULTS: Postoperative radiographs and CT were performed. In the postoperative evaluation, the sacroiliac joint reduction percentage was almost 90% and there was no significant difference in pelvic canal diameter ratio before and after surgery. Screw depth/sacral width was >60% in all cadavers. On CT, the angle between the screw and sacrum wing was within the normal range of 96.24° to the left and 98.65° to the right, except in one case. CONCLUSIONS AND RELEVANCE: In previous studies, surgical repair was based on having an intact contralateral ilium. However, this method is not applicable to patients with bilateral sacroiliac luxation and is mostly performed using open reduction methods. The screw insertion point suggested in this study offers a potential alternative repair technique for patients with bilateral sacroiliac luxation.

Patellofemoral contact mechanics after transposition of tibial tuberosity in dogs.

BACKGROUND: Tibial tuberosity transposition (TTT) causes caudalization of the patellar ligament insertion in canine medial patellar luxation, which can lead to increases in patellofemoral contact pressure. OBJECTIVES: The purpose of this study is to confirm the effect of patellofemoral contact mechanics after craniolateral and caudolateral transposition of tibial tuberosity in normal canine hindlimbs. METHODS: Craniolateral and caudolateral transposition of tibial tuberosity was performed in 5 specimens, respectively. The pressure was measured in the specimen before TTT, and then in the same specimen after TTT. In this process, data was obtained in 10 specimens. The measurement results were output as visualization data through the manufacturer's software and numerical data through spreadsheet. Based on these 2 data and the anatomical structure of the patellofemoral joint (PFJ) surface, whole measurement area was analysed by dividing into medial, lateral and central area. RESULTS: In craniolateralization of tibial tuberosity, total, medial, central contact pressure was decreased and lateral contact pressure was not statistically changed lateral contact pressure than normal PFJ. In caudolateralization of tibial tuberosity, total, lateral contact pressure was increased and medial contact pressure was not statistically changed than normal PFJ. Although not statistically significant changed, central contact pressure in caudolateralization of tibial tuberosity was increased in all 5 specimens. CONCLUSIONS: These results imply that traditional TTT, prone to caudal shift of patellar tendon, can increase retropatellar pressure may lead to various complications and diseases of the stifle joint.