A systematic review on prevention of methicillin-resistant Staphylococcus aureus infection by pre-admission screening: the cost effectiveness and practicality

Background: Methicillin Resistant Staphylococcus aureus (MRSA) is a common source of nosocomial infection, which is spreading through the community and hospitals across the countries. The performance of screening program really needs major effort related to laboratory capacity and ethical consideration, among other costly components. Significant literature research was conducted to review the cost, effectiveness and practicality of different methods of pre-admission MRSA screening in the hospital setting. A systematic literature review was conducted with search strategy using the PubMed Medline, Scopus and the Science Direct databases. The relevant data was abstracted from all studies based on various countries which in line with the finalized eligibility criteria. Results: PCR method was reported to have high sensitivity with low turnaround time as compared to culture method. A review of selected studies found the increasing annual costs of screening from standard culture, chromogenic agar to rapid PCR. In the meantime, other studies reported the total costs for labor and materials was lower for rapid PCR screening compared to culture methods. The culturing method offers a high level of variability due to time consumption and additional costs. Whereas PCR was reported as advantageous in term of saving time to identify MRSA positive patients, which involved isolation, thus increase the effectiveness of screening programs. It can pick up false negative results by conventional methods in the early condition of disease. Conclusion: Most studies verified that PCR is the most accurate method for detection of MRSA with Xpert MRSA having the best performance. Otherwise, oxacillin agar screen was revealed as a good alternative method to PCR. Targeted screening on high risk patients using rapid PCR may be the best choice to be implemented, in order to balance the economic and practicality of screening. We recommend that further clinical studies should be done to provide a sharp evidence of MRSA screening

A new constitutive model of a magneto-rheological fluid actuator using an extreme learning machine method

In this work, a new constitutive model of a magneto-rheological fluid (MRF) actuator is proposed using an extreme learning machine (ELM) technique to enhance the prediction accuracy of the field-dependent actuating force. After briefly reviewing existing rheological constitutive models of MRF actuator, ELM algorithm is formulated using a single-hidden layer feed-forward neural network. In this formulation, both the magnetic field and measured shear rates are used as inputs variables, while the shear stress predicted from the ELM training is used as an output variable. Subsequently, in order to validate the effectiveness of the proposed model, the target defined as the error between the prediction and measured data is set. Then, the fitness of the training and prediction performances is evaluated using a normalized root mean square error (NRMSE) method. It is shown that the shear stress estimation based on the ELM model using sinusoidal activation function is more accurate than conventional rheological constitutive models such as Herschel-Bulkley model. It is also demonstrated that the proposed model is capable of predicting the field-dependent yield stress which is defined as an actuating force of the MRF actuator without causing significant errors

The influence of pretreatment step on hollow braided PET fabric as a potential membrane substrate

Self-supporting polymeric hollow fiber membranes prepared using non-solvent induced phase separation (NIPS) often suffer deterioration in mechanical properties due to asymmetric fingerlike and spongelike morphology giving a porous and fragile structure. Hollow braided fibers of Polyethylene terephthalate (PET) have been used as substrate to increase the strength of hollow fiber membranes. However, problems arise from poor interfacial bonding between the braid and coating polymer resulting in peeling off or delamination at the interface. In this work, we report a method of braid treatment and selection with two alkali treatment steps (NaOH and KOH) to study their effect on pure water flux, water contact angle, tensile strength as well as braid morphology of three different braid samples (B1, B2 and B3). B2 sample treated in KOH demonstrated the highest water flux of 1388 L/m2h. Examination of surface morphology of the braids revealed a washing effect and enlargement of braid interspaces making them more porous and hence increased permeability, with a contact angle of 0° with water. The sample also exhibited zero weight loss as well as a remarkable tolerance for high temperature with negligible reduction in tensile strength of only about 0.9%. Membrane fabricated with B2-K was demonstrated to have better adhesion between polymer-braid interface in comparison to the control. The pre-treatment step provides a good braid selection basis for onward membrane development with KOH showing the most favorable outcome without losing braid quality