PREPARATION OF CHITOSAN-TPP NANOPARTICLES: THE INFLUENCE OF CHITOSAN POLYMERIC PROPERTIES AND FORMULATION VARIABLES

Objective: The aim of this work was to prepare chitosan nanoparticles (CS NPs) using sodium tripolyphosphate (TPP) as crosslinker and to study the effect of chitosan polymeric properties and experimental conditions on the properties and stability of NPs.Methods: CS NPs were prepared by ionic gelation method, using TPP as a crosslinker. The particle size (PS), polydispersity index (PDI), zeta potential (ZP) and the morphologies of the NPs were studied. CS NPs prepared by varying the concentration of TPP, Chitosan molecular weight and its degree of deacetylation, the stirring speed, the rate of TPP addition and the freeze-drying method to study the effect of these variables on the NPs. The stability of the CS NPs was evaluated by storing aqueous suspensions of NPs and comparing the PS, PDI and ZP at the beginning and the end of the experiment.Results: This study shows that the PS, ZP and dispersity of the NPs depend on the chitosan polymeric properties and experimental conditions. The NPs sizes range between 145.73 and 724.23 nm. They all carried positive charges ranging between+4.32 and+43.67 mV. Most of the NPs have the same sizes after freeze-drying, but showed higher monodispersity and ZP, indicating higher stability. After twenty days of studying the stability, the NPs that had low ZP showed a large increment in size in comparison to the highly charged NPs.Conclusion: In conclusion, the polymeric properties and formulation variables in the ionic gelation method have a great influence on the CS NPs formed

Nanocomposite-based dual enzyme system for broad-spectrum scavenging of reactive oxygen species

A broad-spectrum reactive oxygen species (ROS)-scavenging hybrid material (CASCADE) was developed by sequential adsorption of heparin (HEP) and poly(L-lysine) (PLL) polyelectrolytes together with superoxide dismutase (SOD) and horseradish peroxidase (HRP) antioxidant enzymes on layered double hydroxide (LDH) nanoclay support. The synthetic conditions were optimized so that CASCADE possessed remarkable structural (no enzyme leakage) and colloidal (excellent resistance against salt-induced aggregation) stability. The obtained composite was active in decomposition of both superoxide radical anions and hydrogen peroxide in biochemical assays revealing that the strong electrostatic interaction with the functionalized support led to high enzyme loadings, nevertheless, it did not interfere with the native enzyme conformation. In vitro tests demonstrated that ROS generated in human cervical adenocarcinoma cells were successfully consumed by the hybrid material. The cellular uptake was not accompanied with any toxicity effects, which makes the developed CASCADE a promising candidate for treatment of oxidative stress-related diseases

The neural correlates of emotion in decision-making

Both neuroscientific and psychology methods are used to study and explain the active neurons of the individuals' brain response when exposed to external stimuli. This study analyses the relevance literature and investigates the neural correlates of emotion, rewards, and motivation in the decision-making process, the emotional interactions between children, adolescents, and ageing. It was reviewed the literature to explore if neuroscientific methods provide accurate information about the role of emotion, reward, and motivation in decision- making mechanisms. The findings showed that the amygdala, medial prefrontal cortex, and ventromedial prefrontal cortex play a central role in processing of emotion which in turn influence decision-making process. While individuals with lesion in the ventromedial prefrontal cortex which is responsible for emotional responses toward risk, reward, and decision-making are not good decision-makers. In addition, the prefrontal cortex plays central role in approach and withdrawal motivational, whereby the right prefrontal cortex associated with withdrawal behavior and the left prefrontal cortex associated with approach behavior

Analysis of Psychological Symptoms Resulting From the COVID-19 Pandemic

The present study aimed to investigate the level of severity of some psychological symptoms resulting from the Coronavirus pandemic, among a sample of Ajman University students in the United Arab Emirates, and to verify the differences between students’ demographic variables. The study used the descriptive-analytical approach and a modified DASS-21 scale, by adding the two scales of phobia and mental distraction to the tool. The reliability of the tool was verified for use on the sample in the current study. The most prominent results indicated that the highest psychological symptoms resulting from the Coronavirus pandemic were phobia (1.53 ± 0.98) with moderate severity, followed by stress (1.44 ± 0.84) with moderate severity, and the lowest was anxiety (1.02 ±0.79) with mild severity. The results also showed that females of the age group (30-40) years and the group less than 30 years of males are the most age categories who developed psychological symptoms. The study recommended the necessity of activating virtual clinical clinics in universities to provide online counseling services to face the psychological repercussions of the Coronavirus pandemic

Composition and content of phenolic acids and avenanthramides in commercial oat products: are oats an important polyphenol source for consumers?

Oats contain a range of phenolic acids and avenanthramides which may have health benefits. Analysis of 22 commercial oat products (oat bran concentrate, oat bran, flaked oats, rolled oats and oatcakes) using HPLC-DAD detected eleven bound and thirteen free + conjugated phenolic acids and avenanthramides. The oat products (excluding concentrate) provided between 15.79 and 25.05 mg total phenolic acids (9.9–19.33 mg bound, 4.96–5.72 mg free + conjugated) and between 1.1 and 2 mg of avenanthramides in a 40 g portion while an 11 g portion of oat concentrate provided 16.7 mg of total phenolic acids (15.17 mg bound, 1.53 mg free + conjugated) and 1.2 mg of avenanthramides. The compositions and concentrations of the components in the different products were broadly similar, with the major component being ferulic acid (58–78.1%). The results show that commercial oat products are a source of phenolic acids and avenanthramides for consumers

Vapor phase mediated cellular uptake of sub 5 nm nanoparticles

Nanoparticles became an important and wide-used tool for cell imaging because of their unique optical properties. Although the potential of nanoparticles (NPs) in biology is promising, a number of questions concerning the safety of nanomaterials and the risk/benefit ratio of their usage are open. Here, we have shown that nanoparticles produced from silicon carbide (NPs) dispersed in colloidal suspensions are able to penetrate into surrounding air environment during the natural evaporation of the colloids and label biological cells via vapor phase. Natural gradual size-tuning of NPs in dependence to the distance from the NP liquid source allows progressive shift of the fluorescence color of labeled cells in the blue region according to the increase of the distance from the NP suspension. This effect may be used for the soft vapor labeling of biological cells with the possibility of controlling the color of fluorescence. However, scientists dealing with the colloidal NPs have to seriously consider such a NP's natural transfer in order to protect their own health as well as to avoid any contamination of the control samples

Current Practices in Global/International Advanced Pharmacy Practice Experiences: Home/Host Country or Site/Institution Considerations

International outreach by schools and colleges of pharmacy is increasing. In this paper, we provide current practice guidelines to establish and maintain successful global/international advanced pharmacy practice experiences (G/I APPEs) with specific recommendations for home/host country and host site/institution. The paper is based on a literature review (2000-2014) in databases and Internet searches with specific keywords or terms. Educational documents such as syllabi and memoranda of understanding (MoUs) from pharmacy programs were also examined. In addition, a preliminary draft was developed and the findings and recommendations were reviewed in a 90-minute roundtable discussion at the 2014 American Association of Colleges of Pharmacy Annual Meeting. Recommendations for the host country include travel considerations (eg, passport, visa, air travel), safety, housing, transportation, travel alerts and warnings, health issues, and financial considerations. For the home country, considerations for establishment of G/I APPE site (eg, vetting process, MoU, site expectations) are described. The paper is a resource for development of new G/I APPEs and provides guidance for continuous quality improvement of partnerships focusing on G/I pharmacy education

Mechanism of polyubiquitination by human anaphase-promoting complex: RING repurposing for ubiquitin chain assembly.

Polyubiquitination by E2 and E3 enzymes is a predominant mechanism regulating protein function. Some RINGE3s, including anaphase-promoting complex/cyclosome (APC), catalyze polyubiquitination by sequential reactions with two different E2s. An initiating E2 ligates ubiquitin to an E3-bound substrate. Another E2 grows a polyubiquitin chain on the ubiquitin-primed substrate through poorly defined mechanisms. Here we show that human APC's RING domain is repurposed for dual functions in polyubiquitination. The canonical RING surface activates an initiating E2-ubiquitin intermediate for substrate modification. However, APC engages and activates its specialized ubiquitin chain-elongating E2 UBE2S in ways that differ from current paradigms. During chain assembly, a distinct APC11 RING surface helps deliver a substrate-linked ubiquitin to accept another ubiquitin from UBE2S. Our data define mechanisms of APC/UBE2S-mediated polyubiquitination, reveal diverse functions of RING E3s and E2s, and provide a framework for understanding distinctive RING E3 features specifying ubiquitin chain elongation

Ping flood attack pattern recognition using a K-Means algorithm in an Internet of Things (IoT) network

Security is the main challenge in Internet of Things (IoT) systems. The devices on the IoT networks are very heterogeneous, many of them have limited resources, and they are connected globally, which makes the IoT much more challenging to secure than other types of networks. Denial of service (DoS) is the most popular method used to attack IoT networks, either by flooding services or crashing services. Intrusion detection system (IDS) is one of countermeasures for DoS attack. Unfortunately, the existing IDSs are still suffering from detection accuracy problem due to difficulty of recognizing features of the DoS attacks. Thus, we need to determine specific features that representing well the traffic attacks, so the IDS will be able to distinguish normal traffic from the attacks. In this work, we investigate ping flood attack pattern recognition on IoT networks. Experiments were conducted using wireless communication with three different scenarios: normal traffic, attack traffic, and combined normal-attack traffic. Each scenario created an associated dataset. The datasets were then grouped into two clusters: normal and attack. The K-Means algorithm was used to produce the clustering results. The average number of packets in the attack cluster was 95 931 packets, and the average in the normal cluster was 4,068 packets. The accuracy level of the clustering results was calculated using a confusion matrix. The accuracy of the clustering using the implemented K-Means algorithm was 99.94%. The rates from the confusion matrix were true negative (98.62%), true positive (100.00%), false negative (0.00%), and false positive (1.38%)