The biocompatibility and mechanical properties of plasma sprayed zirconia coated abutment

Huang, Zhengfei,Wang, Zhifeng,Yin, Kaifeng,Li, Chuanhua,Guo, Meihua,Lan, Jing The Korean Academy of Prosthodonitics 2020 The Journal of Advanced Prosthodontics Vol.12 No.3

PURPOSE. The aim of this study was to evaluate the clinical performance and reliability of plasma sprayed nanostructured zirconia (NSZ) coating. MATERIALS AND METHODS. This study consisted of three areas of analysis: (1) Mechanical property: surface roughness of NSZ coating and bond strength between NSZ coating and titanium specimens were measured, and the microstructure of bonding interface was also observed by scanning election microscope (SEM). (2) Biocompatibility: hemolysis tests, cell proliferation tests, and rat subcutaneous implant test were conducted to evaluate the biocompatibility of NSZ coating. (3) Mechanical compatibility: fracture and artificial aging tests were performed to measure the mechanical compatibility of NSZ-coated titanium abutments. RESULTS. In the mechanical study, 400 ㎛ thick NSZ coatings had the highest bond strength (71.22 ± 1.02 MPa), and a compact transition layer could be observed. In addition, NSZ coating showed excellent biocompatibility in both hemolysis tests and cell proliferation tests. In subcutaneous implant test, NSZ-coated plates showed similar inflammation elimination and fibrous tissue formation processes with that of titanium specimens. Regarding fatigue tests, all NSZ-coated abutments survived in the five-year fatigue test and showed sufficient fracture strength (407.65-663.7 N) for incisor teeth. CONCLUSION. In this study, the plasmasprayed NSZ-coated titanium abutments presented sufficient fracture strength and biocompatibility, and it was demonstrated that plasma spray was a reliable method to prepare high-quality zirconia coating.

Edit Propagation for Natural Image Using Matting Affinity

Shanshan Huang,Zhifeng Xie,Lizhuang Ma (사)한국CDE학회 2010 한국CAD/CAM학회 국제학술발표 논문집 Vol.2010 No.8

The popularity of stroke-based image/video appearance editing is increasing in image processing field because of the intuitive, easy-to-control interactive interface. In this paper, we propose a new approach to editing natural image that adopts a stroke-based workflow. In our framework, the user paints a few simple brush strokes on region of interest and specifies edit value on each region. These constraints are propagated to the rest of the image by building an energy minimization formulation under the policy that pixels with similar appearance should receive similar edits. In this paper, we design a new energy minimization formula which can be solved by a linear sparse matrix system. Rather than implying a global affinity is used to measure the similarity of pixel pairs, which especially works well in editing fuzzy images. Experiment results show the effectiveness of our method, which is applicable for a variety of adjustments commonly performed in the digital darkroom.

Energy-saving Design Method for Hydraulic Press Drive System with Multi Motor-Pumps

Haihong Huang,Xiang Zou,Lei Li,Xinyu Li,Zhifeng Liu 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.6 No.2

Large energy consumption caused by the pump unloading, as well as the low energy efficiency of the motor, is a serious problem for hydraulic presses especially for the press with multi motor-pumps. By analyzing the energy dissipation characteristic of hydraulic press drive system which is composed of several motor-pumps used to provide energy, an energy-saving design method is developed to reduce the energy loss of the drive system. In this method, pumps are selected from the pump set by minimizing the proposed idling index to reduce the energy loss of motor-pumps in the unloading state. The index is defined as the sum of the product of the unloaded flow and the unloaded time for each stage in a working cycle of the hydraulic press. Then, the motors are selected from the motor set to drive the selected pumps correspondingly by ensuring that the load rate of all the motors is within a setting range for high energy efficiency in as many stages as possible. The method was applied to a 2000-ton rapid sheet tension hydraulic press, and results indicate that 26.97% of energy can be saved in a working cycle.

Energy Consumption Evaluation in Stamping Workshops via a Discrete Event Simulation-Based Approach

Wei Xiong,Haihong Huang,Lei Li,Lei Gan,Libin Zhu,Zhifeng Liu 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.6

Stamping is employed in a wide range of applications in industry, which is composed of discrete flow energy-intensive processes. Durations of stamping activities are much shorter than that of mold changing and transportation, which makes energy consumption in stamping workshops greatly affected by the production scheme and the proportion of transportation volume. Different from machining that has been widely discussed, there is less research on energy saving in stamping workshops. This paper aims to evaluate the energy consumption of stamping on the workshop level. A theoretical model and a discrete event simulation model were developed based on energy flow and material flow in the workshop. The theoretical model was used to calculate each component of energy consumption based on production-related data. The simulation model was used to predict the overall energy required in the workshop when subjected to changes in its production conditions. Impacts of influence factors, including machine failure rate, proportion of transportation volume, and production scheme on energy consumption, makespan, and machine utilization rates, were studied to find opportunities for energy reduction and production efficiency improvement. Finally, a case study of a stamping workshop for forklifts validated the proposed approach, and optimization measures were suggested, implemented, and verified. Results have found that under the same production scheme (suppose each press has the same failure rate), the balance between energy use and makespan was achieved when the proportion of transportation volume was 1/2. This simulation-based approach provides a useful tool for evaluating and reducing energy consumption and helps operators to perform energy-saving actions in stamping workshops.

CFRP Reclamation and Remanufacturing Based on a Closed-loop Recycling Process for Carbon Fibers Using Supercritical N-butanol

Weihao Liu,Haihong Huang,Huanbo Cheng,Zhifeng Liu 한국섬유공학회 2020 Fibers and polymers Vol.21 No.3

This study presents a closed-loop recycling process for carbon fibers using supercritical n-butanol. In thereclamation process, to achieve the highest composite recovery efficiency, the degradation of the carbon fiber-reinforcedepoxy resin composites was conducted at various experimental feedstock ratios (ratio of composite waste to n-butanol), thenthe reclaimed carbon fiber (RCF) was characterized using various methods to develop an understanding of the changes in theproperties and morphologies. In the remanufacturing process, in order to evaluate the reusability of the RCFs and thefeasibility of the closed-loop recycling process for carbon fibers, the RCFs were mixed with new epoxy resin andpolypropylene to remanufacture the composites, and then the mechanical properties of remanufacture composites weretested. The results show that, under an optimized process, the maximum recovery efficiency (feedstock ratio) of thecomposite was 0.1 g/ml. The impact of reclamation process on RCF lies in the degradation of tensile properties and theremoval of sizing agent, which leads the change of the interfacial bonding strength between RCF and new resin, andeventually results in an impact on the performance of remanufacture composites. Compared with the virgin carbon fiberreinforcedcomposites, the improvement in the RCF-reinforced polypropylene properties and insubstantial variations in thetensile properties of the RCF validate the potential of the closed-loop recycling process for carbon fibers.

Development of covalent inhibitors that can overcome resistance to first-generation FGFR kinase inhibitors

Tan, Li,Wang, Jun,Tanizaki, Junko,Huang, Zhifeng,Aref, Amir R.,Rusan, Maria,Zhu, Su-Jie,Zhang, Yiyun,Ercan, Dalia,Liao, Rachel G.,Capelletti, Marzia,Zhou, Wenjun,Hur, Wooyoung,Kim, NamDoo,Sim, Taebo,G National Academy of Sciences 2014 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.111 No.45

<P><B>Significance</B></P><P>Inhibitors of the FGF receptors (FGFRs) are currently under clinical investigation for the treatment of various cancers. All currently approved kinase inhibitors eventually are rendered useless by the emergence of drug-resistant tumors. We used structure-based drug design to develop the first, to our knowledge, selective, next-generation covalent FGFR inhibitors that can overcome the most common form of kinase inhibitor resistance, the mutation of the so-called “gatekeeper” residue located in the ATP-binding pocket. We also describe a novel kinase inhibitor design strategy that uses a single electrophile to target covalently cysteines that are located in different positions within the ATP-binding pocket. These results have important implications for the design of covalent FGFR inhibitors that can overcome clinical resistance.</P><P>The human FGF receptors (FGFRs) play critical roles in various human cancers, and several FGFR inhibitors are currently under clinical investigation. Resistance usually results from selection for mutant kinases that are impervious to the action of the drug or from up-regulation of compensatory signaling pathways. Preclinical studies have demonstrated that resistance to FGFR inhibitors can be acquired through mutations in the FGFR gatekeeper residue, as clinically observed for FGFR4 in embryonal rhabdomyosarcoma and neuroendocrine breast carcinomas. Here we report on the use of a structure-based drug design to develop two selective, next-generation covalent FGFR inhibitors, the FGFR irreversible inhibitors 2 (FIIN-2) and 3 (FIIN-3). To our knowledge, FIIN-2 and FIIN-3 are the first inhibitors that can potently inhibit the proliferation of cells dependent upon the gatekeeper mutants of FGFR1 or FGFR2, which confer resistance to first-generation clinical FGFR inhibitors such as NVP-BGJ398 and AZD4547. Because of the conformational flexibility of the reactive acrylamide substituent, FIIN-3 has the unprecedented ability to inhibit both the EGF receptor (EGFR) and FGFR covalently by targeting two distinct cysteine residues. We report the cocrystal structure of FGFR4 with FIIN-2, which unexpectedly exhibits a “DFG-out” covalent binding mode. The structural basis for dual FGFR and EGFR targeting by FIIN3 also is illustrated by crystal structures of FIIN-3 bound with FGFR4 V550L and EGFR L858R. These results have important implications for the design of covalent FGFR inhibitors that can overcome clinical resistance and provide the first example, to our knowledge, of a kinase inhibitor that covalently targets cysteines located in different positions within the ATP-binding pocket.</P>

In-Situ Precipitated Needle Like Nanocrystalline β-Ti Reinforced Porous Titanium Alloy via Molten Salt Electrolysis

Hao Wang,Jiahao Zhao,Honglin Li,Zhifeng Huang,Yangwei Wang,Qiang Shen,Fei Chen 대한금속·재료학회 2024 METALS AND MATERIALS International Vol.30 No.1

Fabricating porous active metals through chemical dealloying poses challenges due to their reactivity and vulnerability tooxidation in aqueous solutions. The objective of this study was to create micron-sized porous Ti alloy by utilizing the Ti–Mo system as a precursor alloy for chemical dealloying. The impact of phase composition and initial microstructure of theprecursor alloys (Tix at% Mo100 − x at%, x = 60 ~ 70) on the morphology of the resulting porous Ti alloy was systematicallyinvestigated. To improve the mechanical strength and minimize oxidized phases during the dealloying process, a molten saltelectrolysis (MSE) method was employed. The strengthening mechanism of MSE on porous Ti alloys encompassed three keyaspects. Firstly, it effectively reduced the presence of oxidized phases, thereby eliminating surface defects. Secondly, MSEfacilitated grain growth and eliminated voids and cracks at the grain boundaries, leading to enhanced mechanical properties. Thirdly, the involvement of a secondary phase contributed to the overall strengthening mechanism. Following MSE treatment,the oxygen content in the porous Ti alloy decreased from over 13 to 5 at%, and needle-like nanocrystalline β-Ti precipitatesformed within the ligament structure. The accumulation and aggregation of compression-induced dislocations at the grainboundaries of the precipitated phase further improved the mechanical properties. In summary, this work presents an innovativeapproach to fabricating porous Ti alloy with low oxygen content, high strength, and adjustable microstructure. It elucidatesthe strength enhancement mechanism by MSE, providing insights for future materials development and applications.

Microstructural Abnormalities of Basal Ganglia and Thalamus in Bipolar and Unipolar Disorders: A Diffusion Kurtosis and Perfusion Imaging Study

Lianping Zhao,Ying Wang,Yanbin Jia,Shuming Zhong,Yao Sun,Zhifeng Zhou,Zhongping Zhang,Li Huang 대한신경정신의학회 2017 PSYCHIATRY INVESTIGATION Vol.14 No.4

Objective: Bipolar disorder (BD) is often misdiagnosed as unipolar depression (UD), leading to mistreatment and poor clinical outcomes. However, little is known about the similarities and differences in subcorticalgray matter regions between BD and UD. Methods: Thirty-five BD patients, 30 UD patients and 40 healthy controls underwent diffusional kurtosis imaging (DKI) and three dimensional arterial spin labeling (3D ASL). The parameters including mean kurtosis (MK), axial kurtosis (Ka), radial kurtosis (Kr), fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (Da), radial diffusivity (Dr) and cerebral blood flow (CBF) were measured by using regions-of-interest analysis in the caudate, putamen and thalamus of the subcortical gray matter regions. Results: UD exhibited differences from controls for DKI measures and CBF in the left putamen and caudate. BD showed differences from controls for DKI measures in the left caudate. Additionally, BD showed lower Ka in right putamen, higher MD in right caudate compared with UD. Receiver operating characteristic analysis revealed the Kr of left caudate had the highest predictive power for distinguishing UD from controls. Conclusion: The two disorders may have overlaps in microstructural abnormality in basal ganglia. The change of caudate may serve as a potential biomarker for UD.