ABSTRACT
Under a global carbon-neutralizing environment, renewable wood is a viable alternative to non-renewable resources due to its abundance and high specific strength. However, fast-growing wood is hard to be applied extensively due to low mechanical strength and poor dimensional stability and durability. In this study, epoxy-acrylic resin-modified wood was prepared by forming a functional monomer system with three monomers [glycidyl methacrylate (GMA), maleic anhydride (MAN), and polyethylene glycol-200-dimethylacrylic acid (PEGDMA)] and filling into the wood cell cavity. The results showed that in the case of an optimal monomer system of nGMA:nPEGDMA = 20:1 and an optimal MAN dosage of 6%, the conversion rate of monomers reached 98.01%, the cell cavity was evenly filled by the polymer, with the cell wall chemically bonded. Thus, a bonding strength of as high as 1.13 MPa, a bending strength of 112.6 MPa and an impact toughness of 74.85 KJ/m2 were applied to the modified wood, which presented excellent dimensional stability (720 h water absorption: 26%, and volume expansion ratio: 5.04%) and rot resistance (loss rates from white rot and brown rot: 3.05% and 0.67%). Additionally, polymer-modified wood also exhibited excellent wear resistance and heat stability. This study reports a novel approach for building new environmentally friendly wood with high strength and toughness and good structural stability and durability.
ABSTRACT
OBJECTIVE: The etiology, clinical presentation, diagnosis, and treatment strategies of chronic pancreatitis (CP) vary significantly between countries. Specifically, the etiology and surgical approaches to treating CP differ between China and Western countries. Therefore, this study aims to compare the disparities in CP profiles and management based on our single-center experience and recent data from the West. METHODS: From January 2007 to December 2017, a total of 130 consecutive patients with histologically confirmed chronic pancreatitis (CP) underwent surgical treatment at the First Affiliated Hospital of Nanjing Medical University. The clinical features, etiology, risk factors, and operative procedures of these CP patients were analyzed and compared with recent data from Western countries. RESULTS: Our patient cohort was predominantly male (3.19:1), with a median age of 50.2 ± 9.8 years. Upper abdominal pain was the most common symptom, present in 102 patients (78.5%). The most common etiology was obstructive factors (47.7%), followed by alcohol (34.6%). The incidence of genic mutation was 2%, significantly lower than rates reported in Western research. Steatorrhea, weight loss, and jaundice were present in 6.9%, 18.5%, and 17.7% of patients, respectively. Pancreatic cysts or pseudocysts were diagnosed in 7 patients (5.4%). The following procedures were performed: Partington procedure in 33 patients (25.4%), Frey procedure in 17 patients (13.2%), Berne procedure in 5 patients (3.9%), Beger procedure in 1 patient (0.8%), pancreaticoduodenectomy in 17 patients (13.1%), pylorus-preserving pancreaticoduodenectomy in 18 patients (13.9%), middle pancreatectomy in 1 patient (0.8%), and distal pancreatectomy in 9 patients (6.9%). Choledochojejunostomy was performed in 14 patients (10.8%), gastroenterostomy in 2 (1.5%), and 15 patients (11.5%) underwent aspiration biopsy. CONCLUSION: Our study confirms that, etiologically, obstructive chronic pancreatitis (CP) is more frequent in the Chinese population than in Western populations. Although diagnostic instruments and operative procedures in China and Western countries are roughly comparable, slight differences exist in relation to diagnostic flowcharts/criteria and the indications and optimal timing of surgery.