Influence of electrospinning parameters on biopolymers nanofibers, with emphasis on cellulose & chitosan

Background

Electrospinning is an effective method for producing high-quality biopolymer nanofibers, such as cellulose and chitosan. Cellulose nanofibers have excellent mechanical properties and biocompatibility, making them a promising material for tissue engineering. Chitosan nanofibers are biodegradable, biocompatible, and antimicrobial, making them ideal for biomedical applications. The electrospinning parameters, including solution concentration, power supply voltage, orifice diameter, temperature, humidity, and flow rate, play a crucial role in determining the nanofiber diameter, morphology, and mechanical properties, as well as their suitability for various applications.

Objective

This systematic review aims to synthesize and evaluate the current evidence on the influence of electrospinning parameters on the production and properties of cellulose and chitosan nanofibers.

Methods

A comprehensive search of electronic databases was conducted to identify relevant studies. The inclusion criteria were studies that investigated the effect of electrospinning parameters on cellulose and chitosan nanofibers.

Results

It was found that for cellulose, the average fiber diameter increased with increasing each of solution concentration, power supply voltage, orifice diameter, temperature, and humidity. Contrary to tip - collector distance and some optimal points in temperature, where average fiber diameter decreased. For chitosan, the change in voltage and tip to collector distance did not alter the average fiber diameter except for some readings of voltage, which behaved differently. On the other hand, the average fiber diameter increased with increasing flow rate.

Conclusion

The review highlights the importance of considering electrospinning parameters in the production of high-quality biopolymer nanofibers and provides insights into the optimization of these parameters for specific applications. This review also highlights the need for further research to better understand the underlying mechanisms of electrospinning and to optimize the process to produce biopolymer nanofibers with improved properties.

Parametric Optimisation of Friction-Stir-Spot-Welded Al 6061-T6 Incorporated with Silicon Carbide Using a Hybrid WASPAS-Taguchi Technique

Friction stir spot welding (FSSW) is one of the most popular fusion joining processes. The process is a solid-state welding process that allows welding of weldable as well as non-weldable materials. As a part of this investigation, weld samples of Al6061-T6 were reinforced with silicon carbide (SiC) powder with an average particle size of 45 µm. Initially, a Taguchi L9 orthogonal array was developed with three factors, i.e., rotational speed of the tool, pre-dwelling time, and diameter of the hole that was filled with SiC before welding. The effects of the SiC particles and process parameters were investigated as tensile-shear load and micro-hardness. The optimisation of parameters in order to maximise the output responses-i.e., strength and hardness of the welded joints-was performed using a hybrid WASPAS-Taguchi method. The optimised process parameters obtained were a 3.5 mm guiding hole diameter, 1700 rpm tool rotation speed, and 14 s of pre-dwelling time.

Corrigendum to "Effect of carbon nano-tubes and dispersions of SiC and Al2O3 on the mechanical and physical properties of copper-nickel alloy" [Heliyon 4 (10) (October 2018) e00876]

[This corrects the article DOI: 10.1016/j.heliyon.2018.e00876.].

The organization of colposcopy services in Ontario: recommended framework

OBJECTIVE

The purpose of this guideline is to help ensure the provision of high-quality colposcopy practices in the province of Ontario, including those conducted as diagnostic procedures in follow-up to an abnormal cervical screening test.

METHODS

This document updates the recommendations published in the 2008 colposcopy guideline from Cancer Care Ontario, The Optimum Organization for the Delivery of Colposcopy Service in Ontario. A systematic review of guidelines was conducted to evaluate the existing evidence and recommendations concerning these key aspects of colposcopy: □ Training, qualification, accreditation, and maintenance of competence□ Practice setting requirements□ Operational practice□ Quality indicators and outcomes.

RESULTS

This guideline provides recommendations on training and maintenance of competence for colposcopists in the practice settings in which colposcopic evaluation and treatments are conducted. It also provides recommendations on operational issues and quality indicators for colposcopy.

CONCLUSIONS

This updated guideline is intended to support quality improvement for colposcopy for all indications, including the follow-up of an abnormal cervical screening test and work-up for lower genital tract lesions that are not clearly malignant. The recommendations contained in this document are intended for clinicians and institutions performing colposcopy in Ontario, and for policymakers and program planners involved in the delivery of colposcopy services.

A cervical smear review in women developing cervical carcinoma with particular reference to age, false negative cytology and the histologic type of the carcinoma

A review of all available cervical smears from 96 women who subsequently developed invasive cervical carcinoma was undertaken. The aim of the study was to determine the incidence of confirmed negative smears prior to the histologic diagnosis of carcinoma and investigate the relationship between the duration and grade of smear abnormality, the patients' age and the histologic types of cervical carcinoma. The results indicate that only 10% of women had confirmed negative smears, the majority occurring more than 7 years before the diagnosis of carcinoma. In contrast, 89% of young women (under 40 years of age) had a significant abnormality (moderate dyskaryosis or worse) up to 6 years before diagnosis. There is evidence to suggest that the preinvasive phase of cervical carcinoma may be shorter in younger women and that the less common types of cervical carcinoma occur more frequently in this group. The combination of inadequate clinical follow up and false negative cytology may have allowed a significant proportion of these women to develop invasive cervical carcinoma. Possible reasons for false negative smears have been identified and methods aimed at decreasing their frequency are discussed.