Performance Evaluation of PLA Based Biocomposites Reinforced with Photografted PALF

In this study, biocomposites were fabricated through a compression moulding technique that used untreated and grafted pineapple leaf fibre separately with polylactic acid (PLA) as a matrix. For grafting, pineapple leaf fibre (PALF) was chemically modified using two different monomers, i.e. 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) solutions, in the presence of methanol (MeOH) and photoinitiator (Darocur-1664) under ultraviolet (UV) radiation with the aim of improving thermo-mechanical characteristics. Based on grafting efficiency and mechanical attributes, the intensity of UV radiation and monomer concentration were maximized. A series of solutions, created by varying the concentrations (10‒60%) of monomers in MeOH along with 2% photoinitiator, were prepared. Experimental results revealed that composites made of PALF grafted with 30% HEMA at the 15th pass and 40% MMA at the 20th pass of UV radiation achieved the optimum mechanical properties compared with an untreated PALF/PLA composite. The optimized solutions were further enhanced by adding various concentrations (0.5‒1.5%) of urea, with the best mechanical features achieved using a 1% concentration of urea. The chemical bonds formed due to photografting were viewed using Fourier transform infrared spectroscopy (FTIR). Degradation behaviour under heat was determined through thermogravimetric analysis, which found that photografted PALF/PLA showed significantly better thermal stability than the untreated composite sample. A water uptake test showed that grafting reduced the water retention capacity of the treated composite significantly. Crystallization characteristics were inspected using a differential scanning calorimeter, which showed that grafted PALF had a substantial effect on the degree of crystallization of PLA. In addition, scanning electron microscopy was used to monitor the interfacial bond, and revealed that interfacial adhesion was enhanced by the incorporation of photografted PALF into the matrix

Modification and Characterization of Biodegradable Chitosan/ Starch-Based Films with Monomer 1,4-Butanediol Diacrylate (BDDA) by Gamma Radiation

Chitosan reinforced starch-based biodegradable films were prepared by solution casting. Tensile strength (TS), tensile modulus (TM), elongation at break (%), and water vapor permeability (WVP) of the 50% chitosan containing starch-based films were found to be 47 MPa, 550 MPa, 16%, and 2.45 g·mm/m2·day·kPa, respectively.Monomer 1,4 butanediol diacrylate (BDDA) was added (0.25-1% by wt) to the starch/chitosan (50:50) based film formulation. Then, films were cast and gamma irradiated from a radiation dose varied from 1 kGy to 25 kGy. Then mechanical and barrier properties were evaluated. The highest TS (80 MPa) and TM (880 MPa) of the films were found by using 0.5% monomer at 5 kGy dose. The WVP of the films were found to be 1.50 g·mm/m2·day·kPa which is 38.77% lower than control starch/chitosan-based films. Molecular interactions due to incorporation of BDDA were supported by Fourier transform infra red (FTIR) spectroscopy. The water uptake of the films pointed out better hydrophobic character due to incorporation of BDDA in starch/chitosan-based films. Surface morphologies of BDDA treated films were examined by scanning electron microscope (SEM) and suggested better morphologies due to BDDA treatment with starch/chitosan-based biodegradable films

Study on clinical features and factors associated with thickness of chronic subdural hematoma in adult

Patients with chronic subdural hematoma encounter certain difficulties in diagnosis, especially in elderly, due to the characteristically non-specific symptoms and signs. Early diagnosis and proper operative treatment, on the other hand, results in complete recovery in most of the cases. In this study, the clinical features and factors of 31 patients with chronic subdural hematoma, associated with the thickness of chronic subdural hematoma were analyzed. The mean age was 62 ± 13.9 years. The maximum hematoma thickness in the axial CT scan was 25 mm. The thickness of hematoma obtained from axial plain CT had a positive relationship with the patient’s age where r=0.895 and p<0.001 signifies that the thickness of hematoma increased with the increasing age. But the hematoma thickness was not related to co-morbidity such as diabetes mellitus, hypertension and ischemic heart disease. The presentation of the patient with higher hematoma thickness with hemiparesis was statistically significant and with lower thickness with headache and vomiting

Comparative studies of mechanical and interfacial properties between jute and bamboo fiber-reinforced polypropylene-based composites

Jute and bamboo fiber-reinforced polypropylene (PP) based composites (50wt% fiber) were fabricated by compression molding. Tensile strength (TS), bending strength (BS), tensile modulus (TM), and bending modulus (BM) of the jutereinforced PP composite were found to be 48, 56, 900, and 1500 MPa, respectively. Then, bamboo fiber-reinforced PP-based composites (50 wt% fiber) were fabricated and the mechanical properties evaluated. The TS, BS, TM, and BM of bambooreinforced PP composites were found to be 60, 76, 4210, and 6210 MPa, respectively. It was revealed that bamboo fiber-based composites had higher TS, BS, TM, and BM compared to jute-based composites. Degradation tests of the composites (jute fiber/PP and bamboo fiber/PP) were performed in soil at ambient conditions for up to 24 weeks. It was revealed that bamboo fiber/PP composite retained its original mechanical properties higher than that of jute fiber/PP composite. The interfacial shear strength of the jute and bamboo fiber-based composites was investigated using the single-fiber fragmentation test and it was found to be 2.14 and 4.91 MPa, respectively. Fracture sides of the composites were studied by scanning electron microscope, and the results revealed poor fiber matrix adhesion for jute fiber-based composites compared to that of the bamboo fiber-based composites

Does R&D spur productivity growth in Australia’s broadacre agriculture? A semi-parametric smooth coefficient approach

© 2018 Informa UK Limited, trading as Taylor & Francis Group This article analyses the role of research and development (R & D) in Australia’s broadacre farming by using the semi-parametric smooth coefficient model. While the conventional production function approach only captures the direct effects of R & D, this methodology captures both the direct impact of a change in R & D on output and the indirect impact through changes in efficiency of use of factor inputs in the production process. Moreover, technical inefficiency is introduced in the model allowing it as a function of R & D. Using a unique state-level dataset covering the period 1995–2007, this empirical study finds that once both the direct and indirect effects are taken into consideration, R & D investments significantly increase outputs. The results also show that there are substantial variations in the effects of R & D on output across the state-level average farm through technology parameters as well as through technical inefficiency. Such variations need to be taken into account when designing policies for investing public R & D in agriculture

Evasion of anti-growth signaling: a key step in tumorigenesis and potential target for treatment and prophylaxis by natural compounds

The evasion of anti-growth signaling is an important characteristic of cancer cells. In order to continue to proliferate, cancer cells must somehow uncouple themselves from the many signals that exist to slow down cell growth. Here, we define the anti-growth signaling process, and review several important pathways involved in growth signaling: p53, phosphatase and tensin homolog (PTEN), retinoblastoma protein (Rb), Hippo, growth differentiation factor 15 (GDF15), AT-rich interactive domain 1A (ARID1A), Notch, insulin-like growth factor (IGF), and Krüppel-like factor 5 (KLF5) pathways. Aberrations in these processes in cancer cells involve mutations and thus the suppression of genes that prevent growth, as well as mutation and activation of genes involved in driving cell growth. Using these pathways as examples, we prioritize molecular targets that might be leveraged to promote anti-growth signaling in cancer cells. Interestingly, naturally-occurring phytochemicals found in human diets (either singly or as mixtures) may promote anti-growth signaling, and do so without the potentially adverse effects associated with synthetic chemicals. We review examples of naturally-occurring phytochemicals that may be applied to prevent cancer by antagonizing growth signaling, and propose one phytochemical for each pathway. These are: epigallocatechin-3-gallate (EGCG) for the Rb pathway, luteolin for p53, curcumin for PTEN, porphyrins for Hippo, genistein for GDF15, resveratrol for ARID1A, withaferin A for Notch and diguelin for the IGF1-receptor pathway. The coordination of anti-growth signaling and natural compound studies will provide insight into the future application of these compounds in the clinical setting

An optimal batch size under a periodic delivery policy

This paper addresses the problem of a manufacturing system that procures raw materials from suppliers in a lot and processes them to convert to finished products. It proposes an ordering policy for raw materials to meet the requirements of a production facility. In turn, this facility must deliver finished products demanded by outside buyers at fixed interval points in time. First, a general cost model is developed considering both raw materials and finished products. Then this model is used to develop a simple procedure to determine an optimal ordering policy for procurement of raw materials and also the manufacturing batch size to minimize the total cost for meeting the customer demand on time. The proposed procedure provides better results than the traditional separate policies. Numerical examples are also presented