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Monodisperse ZrO2 ceramic beads with size larger than 1 mm have been prepared by an improved micro‐droplet spray forming process, through which a compressor and a dispenser were employed to produce droplets continuously. Furthermore, the slurry recipe and drying temperature have been optimized to enhance the sphericity and smoothness of the beads. The sintered ZrO2 ceramic beads present promising mechanical performance, including a relative density of 84.6%, a crush strength of 256.2 ± 36.6 N as well as a Vickers hardness of 1344.4 ± 58.3 HV. Such procedure reveals great potential in mass production of ceramic beads. [ABSTRACT FROM AUTHOR]

Composites of ZrC- SiC with relative densities in excess of 98% were prepared by reactive hot pressing of ZrC and Si at temperature as low as 1600°C. The reaction between ZrC and Si resulted in the formation of ZrC1− x, SiC, and ZrSi. Low-temperature densification of ZrC− SiC ceramics is attributed to the formed nonstoichiometric ZrC1− x and Zr- Si liquid phase. Adding 5 wt% Si to ZrC, the three-point bending strength of formed ZrC0.8-13.4 vol% SiC ceramics reached 819 ± 102 MPa with hardness and toughness being 20.5 GPa and 3.3 MPa·m1/2, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Unidirectional SiO2f/SiO2 composites were processed with pressureless sintering and hot-pressing, respectively. The influences of the sintering temperature, atmosphere and pre-treatment on the properties were studied. It was found that both higher sintering temperature and air atmosphere promoted the crystallization of the silica fiber, which results in degrading the fiber properties and thus restrained the enhancement of mechanical properties of SiO2f/SiO2 composites. Flexural strength of the fibrous composites sintered with hot-pressing was higher than that for pressureless sintering. The promoted mechanical properties were attributed to the pull-out of the fiber. The in situ formed pyrolytic carbon (PyC) layer on the fiber was beneficial to the properties of the fiber, however, detrimental to the dielectric properties. [Copyright &y& Elsevier]

Abstract: In this paper, ZrO2 removing reactions of Groups IV–VI transition metal carbides (MCs, M=Hf, Nb, Ta, W, Ti and V) in ZrB2 based ultra-high temperature ceramics (UHTCs) are investigated. Distinct roles of various MCs were observed during this process. According to thermodynamic analysis and experiment verifications, the sequence for oxide removing ability of different MCs is WC>VC>NbC>TaC>HfC>TiC. The importance of this study concerns the establishment of a map of reactivity of the transition metal carbides against ZrO2, in order to choose the proper additive for the densification of ZrB2-composites.Utilizing right reactions and controlling proper sintering atmospheres, high density ZrB2–SiC ceramic could be eventually obtained by pressureless sintering at temperatures (around 2000–2200°C). [ABSTRACT FROM AUTHOR]

To evaluate the clinical outcomes of the modified lateral approach combined with the medial percutaneous approach (MLACMPA) versus the triceps tongue-shaped flap approach (TTSFA) and the bilateral triceps brachii approach (BTBA) in the treatment of irreducible displaced supracondylar humeral fractures (SHFs) in children. Between March 2000 and July 2022, a total of 135 children who underwent open reduction and Kirschner wire cross internal fixation for irreducible displaced SHFs caused by trauma were retrospectively analyzed. According to the surgical approach, the patients were assigned to the TTSFA group (n = 36), the BTBA group (n = 40) and the MLACMPA group (n = 59). The duration of surgery, intraoperative blood loss, incision length, and elbow range of motion were compared. The 3 groups were similar in terms of mean age, sex distribution, and time from injury to operation. The duration of surgery, intraoperative blood loss, incision length and postoperative elbow range of motion in the MLACMPA group were significantly superior to those in the TTSFA group and BTBA group (P < .05). Compared the use of the TTSFA or the BTBA, using the MLACMPA for pin fixation in the treatment of irreducible displaced pediatric SHFs could significantly shorten the duration of surgery, reduce the operation trauma, facilitate earlier functional exercise of joints after operation and yield better elbow function., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

Aim: To investigate the splenic hilar vascular anatomy and the influence of splenic artery (SpA) type in laparoscopic total gastrectomy with spleen-preserving splenic lymphadenectomy (LTGSPL)., Methods: The clinical anatomy data of 317 patients with upper- or middle-third gastric cancer who underwent LTGSPL in our hospital from January 2011 to December 2013 were collected. The patients were divided into two groups (concentrated group vs distributed group) according to the distance between the splenic artery's furcation and the splenic hilar region. Then, the anatomical layout, clinicopathologic characteristics, intraoperative variables, and postoperative variables were compared between the two groups., Results: There were 205 patients with a concentrated type (64.7%) and 112 patients with a distributed type (35.3%) SpA. There were 22 patients (6.9%) with a single branch of the splenic lobar vessels, 250 (78.9%) with 2 branches, 43 (13.6%) with 3 branches, and 2 patients (0.6%) with multiple branches. Eighty seven patients (27.4%) had type I splenic artery trunk, 211 (66.6%) had type II, 13 (4.1%) had type III, and 6 (1.9%) had type IV. The mean splenic hilar lymphadenectomy time (23.15 ± 8.02 vs 26.21 ± 8.84 min; P = 0.002), mean blood loss resulting from splenic hilar lymphadenectomy (14.78 ± 11.09 vs 17.37 ± 10.62 mL; P = 0.044), and number of vascular clamps used at the splenic hilum (9.64 ± 2.88 vs 10.40 ± 3.57; P = 0.040) were significantly lower in the concentrated group than in the distributed group. However, the mean total surgical time, mean total blood loss, and the mean number of harvested splenic hilar lymph nodes were similar in both groups (P > 0.05 for each comparison). There were also no significant differences in clinicopathological and postoperative characteristics between the groups (P > 0.05)., Conclusion: It is of value for surgeons to know the splenic hilar vascular anatomy when performing LTGSPL. Patients with concentrated type SpA may be optimal patients for training new surgeons.

In the crystal structure of the title compound, C(18)H(23)NO(2), there are only van der Waals inter-actions present. The cyclo-hexyl ring has a chair conformation. The longer axes of the displacement parameters of the non-H atoms forming the ethyl-methyl-carboxyl-ate skeleton are perpendicular to the plane through the non-H atoms of this skeleton.

Objective: To determine the value of using a closed-suction drain in cemented knee arthroplasty., Methods: One hundred patients were prospectively randomized into two groups, one group underwent cemented total knee replacement with a single deep closed-suction drain, and the other group (n = 50) no drain., Results: The total blood loss was significantly greater in those with a drain although those without lost more blood into the dressings. There was no statistical difference in the postoperative swelling or pain score, ecchymosis, deep vein thromboses (DVT), time at which flexion was regained or the incidence of infection at a minimum of two years after surgery in the two groups., Conclusion: There is no evidence to support the use of a closed-suction drain in cemented knee arthroplasty.

Objective: To study the effect of rotational alignment of the femoral components on the patellofemoral biomechanics in total knee arthroplasty (TKA) demonstrated on autopsy specimens, as the guide for surgeons to choose the correct reference axis for rotational alignment of the femoral components and to reduce the patellofemoral joint complications., Methods: Select 9 frozen fresh human cadaver knees without gross deformities or instabilities and mount specimens on a patellofemoral joint testing jig connected to a Model 8501 Instron machine (Instron Corporation, Canton, MA). The study simulated the action of squatting from the standing position with the foot firmly planted. Standard TKA was performed in each specimen by the same senior surgeon using Nexgen LPS total knee system (Zimmer Corporation, Warsaw Indiana). Alter rotational alignment of the femoral components referenced to the transepicondylar axis and the Whiteside's line respectively. Measure biomechanics of the patellofemoral joints using Fuji prescale film at 30 degrees , 60 degrees , 90 degrees , 120 degrees of knee flexion respectively. The digital values were obtained by the handheld pressure measurement systems (FPD-305E, FPD-306E) and Autocad software., Results: The rotational alignment of the femoral components paralleled to the transepicondylar axis had the best results of the peak value of the patellofemoral contact pressure (P < 0.05). There were no statistically significant differences in patellofemoral contact area (P > 0.05). But the patellofemoral contact area had the close correlations to the angles of the knee flexion and the specimens., Conclusions: Rotational alignment of the femoral components has a great influence on the patellofemoral contact pressure in total knee arthroplasty. It is reliable for surgeons to choose the transepicondylar axis as the reference axis to rotate femoral components.

Objective: To identify possible reasons of rotational mismatch between tibial component and femoral component in total knee arthroplasty and choose a right reference axis for placing the components in the operation and to decrease the complications., Methods: Forty normal Chinese knees were studied. There were 20 men and 20 women, and average age was 34 years (range, 18 - 42 years). The images of cross sections of the distal femur were obtained by spiral CT scanning (0.5 mm thickness). Scan direction was aligned to be in the plane perpendicular to the mechanical axis of the tibia. On the images of the distal femur and the proximal tibia, three baselines for the anteroposterior axis of the femoral component were drawn based on the clinical epicondylar axis and the surgical epicondylar axis and 3 degrees lateral rotated to the posterior condylar surfaces of the femur separately, and a baseline for the anteroposterior axis of the tibial component was drawn based on the medial 1/3 of the tibial tuberosity. The rotational mismatch angles were measured between each component by using the Autocad software., Results: The mean rotational mismatch angle between tibial component and femoral component is 2.94 degrees for the clinical epicondylar axis, 6.50 degrees for the surgical epicondylar axis and 6.83 degrees for 3 degrees lateral rotation of the femoral component referenced to the posterior condylar axis separately., Conclusions: Landmarks of each bone were the intrinsic cause of the rotational mismatch in total knee arthroplasty. The clinical epicondylar axis can be chosen for the ideal reference to rotational alignment of the femoral component because of its minimal rotational mismatch between each component.