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As the understanding of natural gas hydrates as a vast potential resource deepens, their importance as a future clean energy source becomes increasingly evident. However, natural gas hydrates trend towards secondary generation during extraction and transportation, leading to safety issues such as pipeline blockages. Consequently, developing new and efficient natural gas hydrate inhibitors has become a focal point in hydrate research. Kinetic hydrate inhibitors (KHIs) offer an effective solution by disrupting the nucleation and growth processes of hydrates without altering their thermodynamic equilibrium conditions. This paper systematically reviews the latest research progress and development trends in KHIs for natural gas hydrates, covering their development history, classification, and inhibition mechanisms. It particularly focuses on the chemical properties, inhibition effects, and mechanisms of polymer inhibitors such as polyvinylpyrrolidone (PVP) and polyvinylcaprolactam (PVCap). Studies indicate that these polymer inhibitors provide an economical and efficient solution due to their low dosage and environmental friendliness. Additionally, this paper explores the environmental impact and biodegradability of these inhibitors, offering guidance for future research, including the development, optimization, and environmental assessment of new inhibitors. Through a comprehensive analysis of existing research, this work aims to provide a theoretical foundation and technical reference for the commercial development of natural gas hydrates, promoting their safe and efficient use as a clean energy resource. [ABSTRACT FROM AUTHOR]

Background: Nasopharyngeal carcinoma is the most frequently diagnosed primary tumor originating from the nasopharynx, and the preferred treatment modality is radiotherapy.Aims: To identify nasopharyngeal carcinoma prognostic factors in patients with residual or recurrent cervical lymph node metastases after radiotherapy.Patients and Methods: The clinicopathologic characteristics and prognoses of 67 nasopharyngeal carcinoma patients with residual or recurrent cervical lymph node metastases who were diagnosed and treated were analyzed retrospectively. The Chi-squared test and Cox proportional hazard regression model were used to investigate associations between survival and clinicopathological features. Cumulative survival plots were obtained using the Kaplan-Meier method.Results: Data analysis using the Cox proportional hazard regression model revealed that the size of residual or recurrent lymph node metastases, level V lymph node involvement, number of involved levels, surgical procedure performed, and distant metastases were significantly associated with overall survival. Chi-squared analysis only determined a significant correlation between distant metastases and patient survival. Furthermore, the Kaplan-Meier analysis demonstrated that the 1-, 3-, and 5-year survival rates for patients were 86.6%, 52.2%, and 38.6%, respectively. Radical neck dissection resulted in substantially longer overall survival than modified neck dissection.Conclusion: The size of residual or recurrent lymph node metastases, level V lymph node involvement, number of involved levels, surgical procedure performed, and presence of distant metastases were prognostic factors for nasopharyngeal carcinoma patients with residual or recurrent cervical lymph node metastases after radiotherapy, with distant metastases being the most important determinant. Classical radical neck dissection is recommended for treating recurrent nodal disease in nasopharyngeal carcinoma. [ABSTRACT FROM AUTHOR]