Robust Stabilization of Linear Time-Delay Systems under Denial-of-Service Attacks.

This research examines new methods for stabilizing linear time-delay systems that are subject to denial-of-service (DoS) attacks. The study takes into account the different effects that a DoS attack can have on the system, specifically delay-independent and -dependent behaviour. The traditional proportional-integral-derivative (PID) acts on the error signal, which is the difference between the reference input and the measured output. The approach in this paper uses what we call the PID state feedback strategy, where the controller acts on the state signal. Our proposed strategy uses the Lyapunov-Krasovskii functional (LKF) to develop new linear matrix inequalities (LMIs). The study considers two scenarios where the time delay is either a continuous bounded function or a differentiable and time-varying function that falls within certain bounds. In both cases, new LMIs are derived to find the PID-like state feedback gains that will ensure robust stabilization. The findings are illustrated with numerical examples.

Robust FOSMC of quadrotor in the presence of slung load.

This study aims to develop a robust control for the quadrotor slung-load system that efficiently follows a reference trajectory. A fractional-order robust sliding mode control has been chosen to control the quadrotor's altitude, position, and attitude. An anti-swing controller was also installed to limit the swing angle of the suspended load. It was created via delayed feedback, in which the quadrotor's position reference trajectory is changed by the difference of the load angles within a specific delayed value. Designing an adaptive FOSMC would control the system when the system uncertainties do not know the bounds. Moreover, the control parameters and the anti-swing controller for the FOSMC can be obtained using some optimization techniques to increase the controllers' accuracy.

Knowledge and attitude of nurses towards diabetic foot care in a secondary health care centre in Malaysia.

INTRODUCTION: Nurses play a vital role in the care and prevention of ulcers in patients with diabetic foot. Patient education, prevention of ulcers and rehabilitation are some of the vital aspects that nurses provide on a daily basis. Thus, good knowledge and attitude of nurses towards diabetic foot ulcers and its care will ensure better patient care. OBJECTIVES: The aim is to study the level of knowledge and attitude of nurses towards diabetic foot ulcers and its care in Hospital Segamat, Malaysia. METHODS: A validated questionnaire was used between February 2019 to May 2019 covering area such as demography, predisposing factors of ulcer formation, characteristics of ulcers, complications of ulcers, and attitude towards diabetic foot care. RESULTS: A total of 101 nurses took part and 57% of the participants scored poorly in the knowledge section of the questionnaire. In all 72% had scored poorly when asked regarding complications of diabetic foot ulcers; 49.5% of the nurses had positive attitude towards diabetic foot care; and 79.3% thought that care for diabetic foot ulcer is timeconsuming. Majority of them think that their colleagues are the main source of information. All demographic variables were deemed to be confounders with the knowledge and attitude of nurses towards diabetic foot ulcers and its care. CONCLUSIONS: Nurses in this centre had poor knowledge towards diabetic foot ulcers and its care. None of the variable studied were correlated with the level know knowledge. Good or poor knowledge of nurses does not correspond equally to good or poor attitude towards diabetic foot ulcers care. More frequent formal training of diabetic foot care would be needed to ensure better knowledge.

Similarity in cyst wall protein (CWP) trafficking between encysting Giardia duodenalis trophozoites and CWP-expressing human embryonic kidney-293 cells.

Cyst wall proteins 1 and 2 (CWP1 and CWP2) are major constituents of the giardial cyst wall and are expressed with similar kinetics by encysting trophozoites. In the present study, we were interested to determine if the expression of giardial CWPs as heterologous proteins in a higher eukaryotic cell would result in their trafficking across the secretory pathway, as is the case in encysting trophozoites. Recombinant (r)CWP1 and rPro-CWP2 were detected in the lysate and culture media of transfected HEK-293 cells. We then conducted intracellular localization experiments using confocal microscopy and found that the proteins were trafficked in membrane enclosed vesicles across the secretory pathway and released to the culture medium by transfected HEK-293 cells. We then dissected the rCWP1 and rPro-CWP2 molecules to identify the portion(s) responsible for their secretion and found that the putative N-terminal signal peptide was sufficient for directing the secretion of rCWP1, while both the putative N-terminal signal peptide and the 13kDa C-terminal regions were necessary for the secretion of rPro-CWP2 by transfected HEK-293 cells. Taken together, these results demonstrate the degree of conservation of signal peptide recognition between lower and higher eukaryotes.

Oral immunization of BALB/c mice with Giardia duodenalis recombinant cyst wall protein inhibits shedding of cysts.

The process of encystation is a key step in the Giardia duodenalis life cycle that allows this intestinal protozoan to survive between hosts during person-to-person, animal-to-person, waterborne, or food-borne transmission. The release of cysts from infected persons and animals is the main contributing factor to contamination of the environment. Genes coding for cyst wall proteins (CWPs), which could be used for developing a transmission-blocking vaccine, have been cloned. Since the immunogenicity of recombinant Giardia CWP is unknown, we have investigated the immunogenicity of recombinant CWP2 (rCWP2) and its efficacy in interfering with the phenomenon of encystation taking place in the small bowels of BALB/c mice vaccinated with the recombinant protein. Here we report that the immunization of BALB/c mice with rCWP2 stimulated the immune system in a manner comparable to that for a live infection with Giardia muris cysts. Fecal and serum anti-rCWP2 immunoglobulin A (IgA) antibodies were detected in the immunized mice. In addition, anti-rCWP2 IgG1 and IgG2a antibodies were detected in the serum. mRNAs coding for Th1 and Th2 types of cytokines were detected in spleen and Peyer's patch cells from immunized mice. When the vaccinated mice were challenged with live cysts, the animals shed fewer cysts. We conclude that rCWP2 is a possible candidate antigen for the development of a transmission-blocking vaccine.