Learning Algorithm effect on Multilayer Feed Forward Artificial Neural Network performance in image coding

One of the essential factors that affect the performance of Artificial Neural Networks is the learning algorithm. The performance of Multilayer Feed Forward Artificial Neural Network performance in image compression using different learning algorithms is examined in this paper. Based on Gradient Descent, Conjugate Gradient, Quasi-Newton techniques three different error back propagation algorithms have been developed for use in training two types of neural networks, a single hidden layer network and three hidden layers network. The essence of this study is to investigate the most efficient and effective training methods for use in image compression and its subsequent applications. The obtained results show that the Quasi-Newton based algorithm has better performance as compared to the other two algorithms

Dark and light rearing during early postnatal life impairs spatial learning of rats in Morris water maze

     In early postnatal life, sensory-driven processes deeply affect structure and function of sensory cortices. Because some visual signals pass from visual cortex to the hippocampal formation, the aim of this study was to investigate the effects of change in visual experience on rat’s spatial learning and memory. This experimental study was carried out on 30 Wistar male rats (45 days old) which were randomly distributed into 3 groups; the CO (Control group) was in 12 light/12 dark cycle through birth to the end of the study, the LR (Light Reared) group was in complete lightness and the DR (Dark Reared) group was in complete darkness (n=10 for each). Using MWM (Morris Water Maze), the animals learned to find a hidden platform for 4 trials per day during 5 days. After removing the platform, spatial memory was tested at day 5 in one trial (probe trial). Our results indicated that in the learning stage, the CO rats spent less time and distance to find the hidden platform than the other groups. There was no difference between all groups in probe trial. Change in visual experience impairs spatial learning of rats in Morris water maze and their spatial memory formation is not influenced

What we need to know about the germ-free animal models

The gut microbiota (GM), as a forgotten organ, refers to the microbial community that resides in the gastrointestinal tract and plays a critical role in a variety of physiological activities in different body organs. The GM affects its targets through neurological, metabolic, immune, and endocrine pathways. The GM is a dynamic system for which exogenous and endogenous factors have negative or positive effects on its density and composition. Since the mid-twentieth century, laboratory animals are known as the major tools for preclinical research; however, each model has its own limitations. So far, two main models have been used to explore the effects of the GM under normal and abnormal conditions: the isolated germ-free and antibiotic-treated models. Both methods have strengths and weaknesses. In many fields of host-microbe interactions, research on these animal models are known as appropriate experimental subjects that enable investigators to directly assess the role of the microbiota on all features of physiology. These animal models present biological model systems to either study outcomes of the absence of microbes, or to verify the effects of colonization with specific and known microbial species. This paper reviews these current approaches and gives advantages and disadvantages of both models

The effect of probiotics mixture on learning and spatial memory in kindled rats

Background: Repeated seizure attacks lead to extensive neuronal damage and cognitive impairment such as memory loss and learning. Probiotics are shown to have some protective actions against neurological disorders. The present study aimed to examine the effect of probiotics on learning, memory and the nitric oxide level in kindled rats. Materials and Methods: In this experimental study, 40 male rats were randomly divided into five groups: control, kindled with penthylenetetrazole (PTZ), kindled and valproic acid (VPA), kindled after probiotic treatment (probiotic + PTZ), and kindled before probiotic treatment (PTZ + probiotic). The animals were treated by a mixture of probiotics for 4 weeks. Chemical kindling was induced by intraperitoneal injection of PTZ (35 mg/kg) every 48 hours for 24 days. The learning and spatial memory were evaluated by the Morris water maze. The serum nitric oxide level was assessed by the Miranda method. Results: No significant difference was observed between the control and VPA groups in terms of memory, learning and serum levels of nitric oxide. Learning (P<0.001) and spatial memory (P<0.05) phenomena were improved in the probiotic supplemented groups compared to the PTZ group. Also, serum nitric oxide levels were reduced in the probiotic supplemented groups (P<0.05). Conclusion: Probiotic supplementation reduces the level of nitric oxide and improves the learning and memory process

Effect of postnatal environmental enrichment on LTP induction in the CA1 area of hippocampus of prenatally traffic noise-stressed female rats

Early-life stress negatively alters mammalian brain programming. Environmental enrichment (EE) has beneficial effects on brain structure and function. This study aimed to evaluate the effects of postnatal environmental enrichment on long-term potentiation (LTP) induction in the hippocampal CA1 area of prenatally stressed female rats. The pregnant Wistar rats were housed in a standard animal room and exposed to traffic noise stress 2 hours/day during the third week of pregnancy. Their offspring either remained intact (ST) or received enrichment (SE) for a month starting from postnatal day 21. The control groups either remained intact (CO) or received enrichment (CE). Basic field excitatory post-synaptic potentials (fEPSPs) were recorded in the CA1 area; then, LTP was induced by high-frequency stimulation. Finally, the serum levels of corticosterone were measured. Our results showed that while the prenatal noise stress decreased the baseline responses of the ST rats when compared to the control rats (P < 0.001), the postnatal EE increased the fEPSPs of both the CE and SE animals when compared to the respective controls. Additionally, high-frequency stimulation (HFS) induced LTP in the fEPSPs of the CO rats (P < 0.001) and failed to induce LTP in the fEPSPs of the ST animals. The enriched condition caused increased potentiation of post-HFS responses in the controls (P < 0.001) and restored the disrupted synaptic plasticity of the CA1 area in the prenatally stressed rats. Likewise, the postnatal EE decreased the elevated serum corticosterone of prenatally stressed offspring (P < 0.001). In conclusion, the postnatal EE restored the stress induced impairment of synaptic plasticity in rats' female offspring

A method of GC-MS analysis of serum metabolites

Metabolites are the intermediate and natural low molecular weight products of metabolic reactions that naturally occur within cells. Metabolomics is a post-genomics study that analyzes metabolic profile in all biological samples. Gas chromatography-mass spectrometry (GC-MS) is a powerful technique that detects volatile components. In this study we evaluate the metabolite profile of serum with a simple method for derivatization. The metabolic profile of serum taken from 16 rats was analyzed using GC-MS after protein precipitation with acetonitrile. Then, it was derivatized with a method requiring the less number and volume of materials. Acquisition chromatograms were pre-processed and analyzed using National Institute of Standards and Technology (NIST) library. We detected 35 metabolites with probability of &gt;60% perfect match according to spectrum fragments analysis by NIST library.This study represents the metabolome profile of serum instead the change of metabolites that can be evaluated by a simple derivatization method

The application of peroxidase mimetic nanozymes in cancer diagnosis and therapy

In recent decades, scholarly investigations have predominantly centered on nanomaterials possessing enzyme-like characteristics, commonly referred to as nanozymes. These nanozymes have emerged as viable substitutes for natural enzymes, offering simplicity, stability, and superior performance across various applications. Inorganic nanoparticles have been extensively employed in the emulation of enzymatic activity found in natural systems. Nanoparticles have shown a strong ability to mimic a number of enzyme-like functions. These systems have made a lot of progress thanks to the huge growth in nanotechnology research and the unique properties of nanomaterials. Our presentation will center on the kinetics, processes, and applications of peroxidase-like nanozymes. In this discourse, we will explore the various characteristics that exert an influence on the catalytic activity of nanozymes, with a particular emphasis on the prevailing problems and prospective consequences. This paper presents a thorough examination of the latest advancements achieved in the domain of peroxidase mimetic nanozymes in the context of cancer diagnosis and treatment. The primary focus is on their use in catalytic cancer therapy, alongside chemotherapy, phototherapy, sonodynamic therapy, radiation, and immunotherapy. The primary objective of this work is to offer theoretical and technical assistance for the prospective advancement of anticancer medications based on nanozymes. Moreover, it is anticipated that this will foster the investigation of novel therapeutic strategies aimed at achieving efficacious tumor therapy