Periodic motions with impact chatters in an impact Duffing oscillator.

The periodic motions of discontinuous nonlinear dynamical systems are very difficult problems to solve in engineering and physics. Until now, except for numerical studies, one cannot find a better way to solve such problems. In fact, one still has difficulty obtaining periodic motions in continuous nonlinear dynamical systems. In this paper, a method is presented systematically for periodic motions in discontinuous nonlinear dynamical systems. The stability and grazing bifurcations of such periodic motions are studied. Such a method is presented through discussion on a periodically forced, impact Duffing oscillator. Thus, periodic motions with impact chatters in a periodically forced Duffing oscillator with one-sidewall constraint are studied. The analytical conditions for motion grazing at the boundary are developed from discontinuous dynamical systems. The impact Duffing oscillator is discretized to generate subimplicit mappings. With impact, the mapping structures are employed to construct specific impact periodic motions for an impact Duffing oscillator. The bifurcation trees of impact chatter periodic motions are achieved semi-analytically. The grazing and period-doubling bifurcations are obtained, and the grazing bifurcations are for the appearing and disappearance for an impact chatter periodic motion. The impact chatter periodic motions with and without grazing are presented for illustration of impact periodic motion complexity in the impact Duffing oscillator.

Effect of gut microbiota in the colorectal cancer and potential target therapy.

The symbiotic interaction between gut microbiota and the digestive tract is an important factor in maintaining the intestinal environment balance. Colorectal cancer (CRC) is a complex disease involving the interaction between tumour cells and a large number of microorganisms. The microbiota is involved in the occurrence, development and prognosis of colorectal cancer. Several microbiota species have been studied, such as Fusobacterium nucleatum (F. nucleatum), Enterotoxigenic Bacteroides fragilis (ETBF), Streptococcus bovis (S. bovis), Lactobacillus, and Bifidobacterium. Studies about the interaction between microbiota and CRC were retrieved from Embase, PubMed, Ovid and Web of Science up to 21 Oct 2021. This review expounded on the effect of microbiota on CRC, especially the dysregulation of bacteria and carcinogenicity. The methods of gut microbiota modifications representing novel prognostic markers and innovative therapeutic strategies were also described.

Prognostic Value of Tumor-Stroma Ratio in Rectal Cancer: A Systematic Review and Meta-analysis.

BACKGROUND: Tumor-stroma ratio (TSR) is a promising new prognostic predictor for patients with rectal cancer (RC). Although several studies focused on this pathologic feature, results from those studies were still inconsistent. METHODS: This research aimed to estimate the prognostic values of TSR for RC. A search of PubMed, EMBASE, and Web of Science was carried out. A meta-analysis was performed on disease-free survival, cancer-specific survival, and overall survival in patients with RC. RESULTS: The literature search generated 1,072 possible studies, of which a total of 15 studies, involving a total of 5,408 patients, were eventually included in the meta-analysis. Thirteen of the 15 articles set the cutoff for the ratio of stroma at 50%, dividing patients into low-stroma and high-stroma groups. Low TSR (rich-stroma) was significantly associated with poorer survival outcome. (DFS: HR 1.54, 95% CI 1.32-1.79; OS: HR 1.52 95% CI 1.34-1.73; CSS: HR 2.05 95% CI 1.52-2.77). CONCLUSION: Present data support TSR to be a risk predictor for poor prognosis in RC patients.

Radiomics of rectal cancer for predicting distant metastasis and overall survival.

BACKGROUND: Rectal cancer (RC) patient stratification by different factors may yield variable results. Therefore, more efficient prognostic biomarkers are needed for improved risk stratification, personalized treatment, and prognostication of RC patients. AIM: To build a novel model for predicting the presence of distant metastases and 3-year overall survival (OS) in RC patients. METHODS: This was a retrospective analysis of 148 patients (76 males and 72 females) with RC treated with curative resection, without neoadjuvant or postoperative chemoradiotherapy, between October 2012 and December 2015. These patients were allocated to a training or validation set, with a ratio of 7:3. Radiomic features were extracted from portal venous phase computed tomography (CT) images of RC. The least absolute shrinkage and selection operator regression analysis was used for feature selection. Multivariate logistic regression analysis was used to develop the radiomics signature (Rad-score) and the clinicoradiologic risk model (the combined model). Receiver operating characteristic curves were constructed to evaluate the diagnostic performance of the models for predicting distant metastasis of RC. The association of the combined model with 3-year OS was investigated by Kaplan-Meier survival analysis. RESULTS: A total of 51 (34.5%) patients had distant metastases, while 26 (17.6%) patients died, and 122 (82.4%) patients lived at least 3 years post-surgery. The values of both the Rad-score (consisted of three selected features) and the combined model were significantly different between the distant metastasis group and the non-metastasis group (0.46 ± 0.21 vs 0.32 ± 0.24 for the Rad-score, and 0.60 ± 0.23 vs 0.28 ± 0.26 for the combined model; P < 0.001 for both models). Predictors contained in the combined model included the Rad-score, pathological N-stage, and T-stage. The addition of histologic grade to the model failed to show incremental prognostic value. The combined model showed good discrimination, with areas under the curve of 0.842 and 0.802 for the training set and validation set, respectively. For the survival analysis, the combined model was associated with an improved OS in the whole cohort and the respective subgroups. CONCLUSION: This study presents a clinicoradiologic risk model, visualized in a nomogram, that can be used to facilitate individualized prediction of distant metastasis and 3-year OS in patients with RC.

Prognostic Value of Pre-Treatment Prognostic Nutritional Index in Esophageal Cancer: A Systematic Review and Meta-Analysis.

Background: Prognostic nutritional index (PNI), combining albumin and lymphocyte counts, which represent the nutritional and immune status, was considered as an effective predictor for the patient's prognosis after surgery. To comprehensively analyze the relative effectiveness of prognostic performance of pretreatment PNI in esophageal cancer (EC), we performed this meta-analysis. Methods: We performed a systematic search in PubMed, Embase, CNKI, and Web of Science. The hazard ratios (HRs) or odds ratios (ORs) with their corresponding 95% confidence intervals (CIs) were extracted to explore the correlation between PNI and the post-operative survival of patients with EC, including overall survival (OS), recurrence-free survival (RFS), and post-operative complications. The Newcastle-Ottawa Scale (NOS) was applied to estimate the quality of the included studies. The Begg's test was applied to assess the publication bias. Results: A total of 13 articles with 3,543 patients, were included in our meta-analysis, and nine studies reported OS in 2,731 EC patients. The pooled results of the nine studies suggested that EC patients with a low PNI would have a worse overall survival (HR = 1.14, 95% CI 0.99-1.31, p < 0.05). The integrated results also indicated that the PNI was a negative predictor for RFS. Conclusion: This meta-analysis indicated a high correlation between PNI and post-operative survival of EC. EC patients with low PNI values tend to have worse OS and may be at a higher risk of EC recurrence. However, more relevant researches are needed to confirm the association between PNI and post-operative complications of EC.

Diagnostic performance of various liquid biopsy methods in detecting colorectal cancer: A meta-analysis.

Liquid biopsy is a promising method in detecting colorectal cancer (CRC). However, previous meta-analyses only focused on the diagnostic performance of cell-free DNA (cfDNA). Therefore, we firstly evaluated the overall performance of all liquid biopsy methods. The pooled sensitivities, specificities, diagnostic odds ratios, and area under curve (AUC) of summary receiver operating characteristic curve for all liquid biopsy methods, exosomes, circulating tumor cells (CTCs), and cfDNA were calculated, respectively. A total of 62 articles involving 18 739 individuals were included. Fifty-one articles were about cfDNA, five articles were about CTCs, and six articles were about exosomes. The overall performance of all liquid biopsy methods had a pooled sensitivity, specificity, and AUC of 0.77 (95% confidence interval [CI] 0.76-0.78), 0.89 (95% CI 0.88-0.90), and 0.9004, respectively. The sensitivities were 0.82 (95% CI 0.79-0.85), 0.76 (95% CI 0.72-0.80), and 0.76 (95% CI 0.75-0.77) for CTCs, exosomes, and cfDNA, respectively. The specificities were 0.97 (95% CI95% CI 0.95-0.99), 0.92 (95% CI 0.89-0.94), and 0.88 (95% CI 0.87-0.89) for CTCs, exosomes, and cfDNA, respectively. The AUC were 0.9772, 0.9037, and 0.8963 for CTCs, exosomes, and cfDNA, respectively. The overall performance of all liquid biopsy methods had great diagnostic value in detecting CRC, regardless of subtypes. Among all liquid biopsy methods, CTCs showed the best diagnostic performance.

Diagnostic value of various liquid biopsy methods for pancreatic cancer: A systematic review and meta-analysis.

BACKGROUND: Liquid biopsy is a novel method for cancer diagnosis, which has been applied in lung and breast cancers, demonstrating high diagnostic value. However, clinical value of it in pancreatic cancer (PC) remains to be verified. The aim of this meta-analysis was to evaluate overall diagnostic value of various liquid biopsy methods (circulating tumor DNA, circulating tumor cells and exosomes) in detecting PC. METHODS: We comprehensively searched relevant studies in PubMed, Medline, Embase, and Web of Science without time limitation according to PRISMA. Data necessary for reconstructing a 2 × 2 table was calculated from the original articles. The methodological quality of included studies was evaluated by QUADAS-2. Statistical analysis including was performed by the software Meta-Disc version 1.4, and STATA 14.2. RESULTS: A total of 19 studies including 1872 individuals were included in this meta-analysis. In which, 7 were studies about ctDNA, 7 were on CTCs and 6 were about exosomes (Sefrioui D, studied diagnostic accuracy of both ctDNA and CTCs, with no common patients in these 2 groups). The pooled sensitivity estimates for ctDNA, CTCs and exosomes in detecting PC with their 95% confidential intervals (95% CI) were 0.64 (95%CI 0.58-0.70), 0.74 (95%CI 0.68-0.79) and 0.93 (95%CI 0.90-0.95), respectively. The pooled specificity estimates were 0.92(95%CI 0.88-0.95), 0.83 (95%CI 0.78-0.88) and 0.92 (95%CI 0.88-0.95), respectively. The area under curve (AUC) of the sROC for ctDNA, CTCs and exosomes in detecting PC were 0.9478, 0.8166, and 0.9819, respectively. The overall sensitivity, specificity and AUC of the sROC curve for overall liquid biopsy in detecting PC were 0.80 (95%CI 0.77-0.82), 0.89 (95%CI 0.87-0.91) and 0.9478, respectively. CONCLUSION: This meta-analysis confirmed that liquid biopsy had high diagnostic value in detecting PC. In ctDNA, CTCs and exosomes these 3 subgroups, exosomes showed highest sensitivity and specificity.

The efficacy of Raman spectroscopy in the diagnosis of esophageal cancer: a systematic review and meta-analysis.

BACKGROUND: Esophageal cancer is characterized by its high occurrence rate and difficulty to treat successfully, therefore early diagnosis is extremely important. Our article is aimed to comprehensively analyze the relative effectiveness of Raman spectroscopy (RS) in the diagnosis of suspected esophageal cancer. METHODS: We performed a systemic search in PubMed, EMBASE, CNKI and Web of science from 2007 to 2020. We used the diagnostic data of true positive (TP), false positive (FP), true negative (TN) and false negative (FN) to estimate the pooled sensitivity, specificity, positive and negative likelihood ratios (LR), and diagnostic odds ratio (DOR), with 95% confidence intervals (CI), based on random effects models. The SROC curve analysis and AUC were performed to estimate the overall performance of Raman spectroscopy. QUADAS-2 guidelines were used to evaluate the quality of each study. RESULTS: Nine articles were included according to our inclusion and exclusion criteria. General pooled diagnostic sensitivity and specificity of RS to esophageal cancer were 0.91 (95% CI, 0.89-0.93) and 0.92 (95% CI, 0.91-0.94). The pooled PLR and NLR were 18.98 (95% CI, 6.61-54.49) and 0.09 (95% CI, 0.05-0.16), respectively. The DOR was 217.21 (95% CI, 68.32-690.53) indicating high accuracy. And the AUC of SROC curve was 0.9779. CONCLUSIONS: We found a promisingly high sensitivity and specificity of RS in the diagnosis of suspected esophageal mass.