Optimization of Structural and Processing Parameters for Selective Laser Melting of Porous 316L Bone Scaffolds.

In the implantation of porous bone scaffolds, good mechanical properties of the scaffold are a prerequisite for the long-term functionality of the implanted scaffolds, which varies according to the structure and the forming process. In this study, the influence of the forming parameters and structure of the Selective Laser Melting (SLM) process on the mechanical properties of 316L stainless steel bone scaffolds was investigated using finite element simulation combined with experimental methods. The mechanism of the influence of the process parameters and structure on the mechanical properties of bone scaffolds was summarized using static compression finite element numerical simulations, compression experiments, hydrodynamic simulations, forming numerical simulations and SLM forming experiments. The results show that the magnitude of residual stress and the distribution of defects under different process parameters had a strong influence on the microstructure and properties of the scaffold, and the residual stress of the Body-Centered Cube (BCC) structure formed at an energy density of 41.7 J/mm3 was significantly reduced, with less surface spheroidization and fewer cracks on the melt pool surface. The smallest grain size of 321 nm was obtained at an energy density of 77.4 J/mm3, while in terms of mechanical properties, the optimization of the structure resulted in an 8.3% increase in yield strength and a reduction in stress concentration. The predictions of stress, deformation, and forming quality during construction with different process parameters, achieved using finite element analysis, are basically in agreement with the experimental results, indicating that the best process parameters for forming BCC structural supports were determined by using finite element simulation combined with experiments; moreover, the distribution and evolution of residual stresses and defects under different process parameters for constructing BCC structures were obtained.

Analysis of Clinical Characteristics of Hepatitis B and Alcohol-Related Liver Cancer.

In order to analyze the clinical characteristics of hepatitis B and alcohol-related liver cancer, this paper combines the investigation and analysis methods to analyze the clinical characteristics of hepatitis B and alcohol-related liver cancer, studies them in combination with the actual situation, and studies multiple parameters with statistical methods. Different causes of liver cancer have different pathogenic mechanisms, which may make the clinical characteristics of liver cancer different. This study mainly explores the difference in clinical characteristics between hepatitis B-related hepatocellular carcinoma and alcohol-related hepatocellular carcinoma. Through comparative analysis and analysis of the clinical characteristics of hepatitis B and alcohol-related liver cancer, the study found that hepatitis B and alcohol-related liver cancer have obvious differences in their impact mechanisms. Therefore, targeted prevention and diagnosis and treatment measures can be put forward on this basis to provide a theoretical reference for subsequent clinical treatment analysis of liver cancer.

Feasibility and efficiency of double-agent versus single-agent concurrent chemoradiotherapy in patients with nasopharyngeal carcinoma.

PURPOSE: Concurrent chemoradiotherapy (CCRT) is the mainstay of treatment for nasopharyngeal carcinoma (NPC) patients. It remains unclear whether double-agent CCRT (d-CCRT) is more effective than single-agent CCRT (s-CCRT). In this study, we compared the treatment efficiency and toxicity of d-CCRT with s-CCRT in NPC patients. METHODS AND MATERIALS: Patients with stage II-IV NPC treated with d-CCRT or s-CCRT were retrospectively reviewed. The d-CCRT group patients were compared with s-CCRT group patients for overall survival (OS), locoregional relapse-free survival (LRRFS), disease-free survival (DFS), distant metastasis-free survival (DMFS) and toxicity. Differences in baseline characteristics were adjusted using the pair-matching method. RESULTS: In this study, 933 patients who received CCRT for NPC between 2011 and 2014 were pair-matched at a 1:2 ratio (n = 311 for d-CCRT; n = 622 for s-CCRT). The d-CCRT treated patients showed no significant advantages in terms of 4-year OS (87.2% vs. 85.5%), DFS (84.1% vs. 79.5%), LRRFS (94.6% vs. 91.8%), DMFS (87.5% vs. 85.5%) compared with s-CCRT treated patients (P = 0.450, 0.106, 0.203, 0.366, respectively). Multivariate analysis showed that CCRT regimen had no significant effects on survival. In the d-CCRT group, the incidence of grade 3-4 hematological toxicities was significantly higher. CONCLUSIONS: The d-CCRT regimen did not confer significant survival benefits compared with the s-CCRT regimen in the treatment of stage II-IV NPC patients. Furthermore, patients treated with the d-CCRT regimen experienced greater hematological toxicity.

Recovered patients with Stevens-Johson syndrome and toxic epidermal necrolysis maintain long-lived IFN-γ and sFasL memory response.

There is evidence that drug-specific T cells are involved in inducing keratinocyte apoptosis in acute stage of Steven-Johson syndrome (SJS) and Toxic epidermal necrolysis (TEN). However, there are few studies that have attempted to examine T cell memory responses over time. We sought to determine the duration of IFN-γ and sFasL memory response to causal drugs in patients with SJS and TEN after remission. Eight patients with previous SJS and TEN were enrolled. Memory T cells were measured by 10-day cultured IFN-γ enzyme-linked immunosorbent spot-forming cell (ELISpot) assay. Effector T-cell responses were measured by ex vivo IFN-γ ELISpot assay and sFasL ELISA. The sFasL-mediated toxicities of drug-stimulated PBMC supernatants against keratinocyte line were further investigated by MTT proliferation assay and Annexin-V staining. We observed significant cultured and ex vivo IFN-γ ELISpot responses against causal drugs in all 8 patients. In addition, the sFasL levels were specifically increased in the supernatant of PBMCs cultured with causal drugs from 6 of 8 patients. Drug-stimulated PBMC supernatants were cytotoxic against keratinocyte line, which was inhibited by anti-FasL mAb in a dose-dependent manner. Our findings confirmed that drug-specific IFN-γ and sFasL memory response against causal drugs could be sustained over several years and further suggest that patients should avoid causal drug re-exposure after the recovery of TEN and SJS.