Complex Recognition Processes Research Articles

ScriptCalc: Handwriting Recognition with Mathematical Equation Solving

Abstract: The present paper proposes a novel algorithm for recognition of handwritten digits. For this, the present paper classified the digits into two groups: one group consists of blobs with/without stems and the other digits with stems only. The blobs are identified based on a new concept called morphological region filling methods. This eliminates the problem of finding the size of blobs and their structuring elements. The digits with blobs and stems are identified by a new concept called ‘connected component’. This method completely eliminates the complex process of recognition of horizontal or vertical lines and the property called ‘concavities’. The digits with only stems are recognized, by extending stems into blobs by using connected component approach of morphology. The present method has been applied and tested with various handwritten digits from modified NIST (National Institute of Standards and Technology) handwritten digit database (MNIST), and the success rate has been given. The present method is also compared with various existing methods. Once the digits are recognized, they are assembled back into their respective positions within the equation. Mathematical equation solving techniques are then applied to evaluate the expression and obtain the result

Enantiomeric Discrimination in Insects: The Role of OBPs and ORs.

Simple SummaryInsects use olfaction, i.e., their sense of smell, to detect odors that elicit behavioral responses, with structurally similar compounds eliciting different responses. The roles of specific recognition proteins, i.e., odorant-binding proteins (OBPs) and odorant receptors (ORs), located in insect antennae, in discriminating between structurally similar compounds are not fully understood. Here, we explore current research in understanding the role of OBPs and ORs in discriminating between enantiomers—mirror image structures—in insect chemical ecology and chemoperception.Olfaction is a complex recognition process that is critical for chemical communication in insects. Though some insect species are capable of discrimination between compounds that are structurally similar, little is understood about how this high level of discrimination arises. Some insects rely on discriminating between enantiomers of a compound, demonstrating an ability for highly selective recognition. The role of two major peripheral olfactory proteins in insect olfaction, i.e., odorant-binding proteins (OBPs) and odorant receptors (ORs) has been extensively studied. OBPs and ORs have variable discrimination capabilities, with some found to display highly specialized binding capability, whilst others exhibit promiscuous binding activity. A deeper understanding of how odorant-protein interactions induce a response in an insect relies on further analysis such as structural studies. In this review, we explore the potential role of OBPs and ORs in highly specific recognition, specifically enantiomeric discrimination. We summarize the state of research into OBP and OR function and focus on reported examples in the literature of clear enantiomeric discrimination by these proteins.

An Integrated Markov State Model and Path Metadynamics Approach To Characterize Drug Binding Processes.

Unveiling the mechanistic features of drug-target binding is of central interest in biophysics and drug discovery. Herein, we address this challenge by combining two major computational approaches, namely, Molecular Dynamics (MD) simulations and Markov State Models (MSM), with a Path Collective Variables (PCVs) description coupled with metadynamics. We apply our methodology to reconstruct the binding process of the antagonist alprenolol to the β2-adrenergic receptor, a well-established pharmaceutical target. The devised protocol allowed us to estimate the binding free energy and identify the minimum free energy path leading to the protein-ligand complex. In summary, we show that MSM and PCVs can be efficiently integrated to shed light upon mechanistic and energetic details underlying complex recognition processes in biological systems.

Faces in the Brain

In this paper it will be investigated the distinction – supported by experimental data – of two different degrees within the so-called face perception : 1) The automatic perception/detection of faces; 2) The recognition of a specific face , that concerns personal meanings association – a story , we could say – to that first automatic perceptual configuration. In general, the first degree is a basic perception process, a universal , innate and early capacity belonging to all human beings. It includes three face-selective regions in the brain, with the OFA and the STS who process the partial data of faces, and the FFA that “produces” the overall basic form. The second degree consists in a complex recognition process, which implies the activation of many cerebral areas with different functions such as, for example, the subcortical regions responsible for emotions modulation ( amygdala , insula ), the intraparietal sulcus , the auditory cortex. It associates a given perceptual pattern with specific semantic entities, which compose a qualitative complex of experience, knowledge and subjective understanding.

Fluoroacetamide Moieties as NMR Spectroscopy Probes for the Molecular Recognition of GlcNAc-Containing Sugars: Modulation of the CH-π Stacking Interactions by Different Fluorination Patterns.

We herein propose the use of fluoroacetamide and difluoroacetamide moieties as sensitive tags for the detection of sugar–protein interactions by simple 1H and/or 19F NMR spectroscopy methods. In this process, we have chosen the binding of N,N′‐diacetyl chitobiose, a ubiquitous disaccharide fragment in glycoproteins, by wheat‐germ agglutinin (WGA), a model lectin. By using saturation‐transfer difference (STD)‐NMR spectroscopy, we experimentally demonstrate that, under solution conditions, the molecule that contained the CHF2CONH‐ moiety is the stronger aromatic binder, followed by the analogue with the CH2FCONH‐ group and the natural molecule (with the CH3CONH‐ fragment). In contrast, the molecule with the CF3CONH‐ isoster displayed the weakest intermolecular interaction (one order of magnitude weaker). Because sugar–aromatic CH–π interactions are at the origin of these observations, these results further contribute to the characterization and exploration of these forces and offer an opportunity to use them to unravel complex recognition processes.

Structural aspects of molecular recognition in the immune system. Part I: Acquired immunity (IUPAC Technical Report)

Abstract Humoral immunity allows the body to mount a defense against pathogens and foreign substances, and to respond with memory to subsequent exposures. The molecular participants may also recognize self-structures, leading to attack on the body and autoimmune disease. The main players in humoral immunity are antibody-producing B lymphocytes, and several classes of T lymphocytes. This review deals with the molecular details of recognition of antigens by soluble antibodies, and of substances presented to receptors on the surfaces of T cells (TCRs). The prototype antibody consists of a dimer of dimers, two heavy (H) chains and two light (L) chains, with antigen recognition capacity lying in variable “head” regions of an H-L pair. Most crystallographic studies are done with this substructure, called a Fab fragment, bound in a soluble antigen complex. Homologous to this arrangement, the prototype TCR consists of two chains (α and β) that complex not soluble antigen, but usually a short peptide or other small molecule presented by proteins of the major histocompatibility complex. In each case a general background on the historical development of understanding the molecular recognition interface is given, followed by a number of examples of crystal structures from the recent literature that have allowed us to refine our understanding of the complex recognition process. Variations on the prototypical structures are also considered. The spectrum of recognition strategies involves interplay of lock-and-key with flexibility, varying degrees of entropic and enthalpic contributions, surface shaping by entrapped water molecules, and combinations of stabilizing hydrogen bonding, electrostatic interactions, salt bridging, and van der Waals forces. Preeminent in the recent literature are details of antibody binding to influenza A and human immunodeficiency viral antigens. Both viral antigens and attempts to understand autoimmunity are prominent in the recent TCR literature.

Study on the Optimization of Complex Computer Network Language Based on TEI Model

With the popularization of internet, cyber language is used more and more frequently. The network language has formed a unique system of computer language library. So studying of computer language has great significance to the development of the network language. Language library capacity cant be unlimited expansion. To enhance the computer language network function we must use correlation algorithm to simplify the computer language. In this paper, an improved method based on the network language new is proposed. We apply the neural network speech recognition model with multi hierarchy recognition technology to computer language, and put forward TEI model of computer network language identification. We use the VB program to call on the MATLAB software, successfully simplify the complex recognition process of the network language. At the same time, computer network language also has certain reference value for English language learning. It can help learners to avoid the negative effects of network language on the English language.

Correction: Large Domain Motions in Ago Protein Controlled by the Guide DNA-Strand Seed Region Determine the Ago-DNA-mRNA Complex Recognition Process

Correction: Large Domain Motions in Ago Protein Controlled by the Guide DNA-Strand Seed Region Determine the Ago-DNA-mRNA Complex Recognition Process

Large Domain Motions in Ago Protein Controlled by the Guide DNA-Strand Seed Region Determine the Ago-DNA-mRNA Complex Recognition Process

The recognition mechanism and cleavage activity of argonaute (Ago), miRNA, and mRNA complexes are the core processes to the small non-coding RNA world. The 5′ nucleation at the ‘seed’ region (position 2–8) of miRNA was believed to play a significant role in guiding the recognition of target mRNAs to the given miRNA family. In this paper, we have performed all-atom molecular dynamics simulations of the related and recently revealed Ago-DNA:mRNA ternary complexes to study the dynamics of the guide-target recognition and the effect of mutations by introducing “damaging” C·C mismatches at different positions in the seed region of the DNA-RNA duplex. Our simulations show that the A-form-like helix duplex gradually distorts as the number of seed mismatches increases and the complex can survive no more than two such mismatches. Severe distortions of the guide-target heteroduplex are observed in the ruinous 4-sites mismatch mutant, which give rise to a bending motion of the PAZ domain along the L1/L2 “hinge-like” connection segment, resulting in the opening of the nucleic-acid-binding channel. These long-range interactions between the seed region and PAZ domain, moderated by the L1/L2 segments, reveal the central role of the seed region in the guide-target strands recognition: it not only determines the guide-target heteroduplex’s nucleation and propagation, but also regulates the dynamic motions of Ago domains around the nucleic-acid-binding channel.

Micorriza arbuscular e a tolerância das plantas ao estresse

Fungos micorrízicos arbusculares (FMAs) são fungos de solo, biotróficos obrigatórios e formadores da simbiose mutualista mais comum na natureza: a micorriza arbuscular (MA). Essa associação ocorre nas raízes da maioria das plantas terrestres, promovendo melhorias no crescimento, desenvolvimento e aumento na tolerância e, ou, resistência das plantas a vários agentes ambientais adversos. Além disso, os FMAs podem ser utilizados como potenciais agentes de controle biológico de doenças de plantas. Esses fungos produzem ainda glomalina, uma proteína que desempenha papel fundamental na estabilidade do solo e bioestabilização de solos contaminados. As diferentes respostas das plantas a essa simbiose podem ser atribuídas à diversidade funcional das MAs, em função da interação FMA-planta-condições ambientais. O estabelecimento e funcionamento da MA durante as condições de estresse envolvem um complexo processo de reconhecimento e desenvolvimento, concomitantemente às alterações bioquímicas, fisiológicas e moleculares em ambos os simbiontes. Além disso, a colonização micorrízica das raízes tem impacto significativo na expressão de genes de diversas plantas que codificam proteínas presumivelmente envolvidas na tolerância ao estresse. Nesse contexto, considerando que os FMAs são essenciais no estabelecimento e adaptação das plantas em locais perturbados, nesta revisão são abordados os mecanismos fisiológicos e moleculares da associação MA responsáveis por essa adaptação e pela maior tolerância das plantas ao estresse.

Classification and recognition of handwritten digits by using mathematical morphology

The present paper proposes a novel algorithm for recognition of handwritten digits. For this, the present paper classified the digits into two groups: one group consists of blobs with/without stems and the other digits with stems only. The blobs are identified based on a new concept called morphological region filling methods. This eliminates the problem of finding the size of blobs and their structuring elements. The digits with blobs and stems are identified by a new concept called ‘connected component’. This method completely eliminates the complex process of recognition of horizontal or vertical lines and the property called ‘concavities’. The digits with only stems are recognized, by extending stems into blobs by using connected component approach of morphology. The present method has been applied and tested with various handwritten digits from modified NIST (National Institute of Standards and Technology) handwritten digit database (MNIST), and the success rate has been given. The present method is also compared with various existing methods.

Self-assembly of amphiphilic dendritic dipeptides into helical pores

Natural pore-forming proteins act as viral helical coats and transmembrane channels, exhibit antibacterial activity and are used in synthetic systems, such as for reversible encapsulation or stochastic sensing. These diverse functions are intimately linked to protein structure. The close link between protein structure and protein function makes the design of synthetic mimics a formidable challenge, given that structure formation needs to be carefully controlled on all hierarchy levels, in solution and in the bulk. In fact, with few exceptions, synthetic pore structures capable of assembling into periodically ordered assemblies that are stable in solution and in the solid state have not yet been realized. In the case of dendrimers, covalent and non-covalent coating and assembly of a range of different structures has only yielded closed columns. Here we describe a library of amphiphilic dendritic dipeptides that self-assemble in solution and in bulk through a complex recognition process into helical pores. We find that the molecular recognition and self-assembly process is sufficiently robust to tolerate a range of modifications to the amphiphile structure, while preliminary proton transport measurements establish that the pores are functional. We expect that this class of self-assembling dendrimers will allow the design of a variety of biologically inspired systems with functional properties arising from their porous structure.

Water-mediated contacts in the trp-repressor operator complex recognition process.

Water-mediated contacts are known as an important recognition tool in trp-repressor operator systems. One of these contacts involves two conserved base pairs (G(6).C(-6) and A(5). T(-5)) and three amino acids (Lys 72, Ile 79, and Ala 80). To investigate the nature of these contacts, we analyzed the X-ray structure (PDB code: 1TRO) of the trp-repressor operator complex by means of molecular dynamics simulations. This X-ray structure contains two dimers that exhibit structural differences. From these two different starting structures, two 10 ns molecular dynamics simulations have been performed. Both of our simulations show an increase of water molecules in the major groove at one side of the dimer, while the other side remains unchanged compared to the X-ray structure. Though the maximum residence time of the concerned water molecules decreases with an increase of solvent at the interface, these water molecules continue to play an important role in mediating DNA-protein contacts. This is shown by new stable amino acids-DNA distances and a long water residence time compared to free DNA simulation. To maintain stability of the new contacts, the preferential water binding site on O6(G6) is extended. This extension agrees with mutation experiment data on A5 and G6, which shows different relative affinity due to mutation on these bases [A. Joachimiak, T. E. Haran, P. B. Sigler, EMBO Journal 1994, Vol. 13, No. (2) pp. 367-372]. Due to the rearrangements in the system, the phosphate of the base G6 is able to interconvert to the B(II) substate, which is not observed on the other half side of the complex. The decrease of the number of hydrogen bonds between protein and DNA backbone could be the initial step of the dissociation process of the complex, or in other words an intermediate complex conformation of the association process. Thus, we surmise that these features show the importance of water-mediated contacts in the trp-repressor operator recognition process.

The generalization of directional visual stimuli in the honey bee, Apis mellifera

In transfer tests the ability of bees to generalize visual stimuli was tested by using differently inclined stripes and stripe patterns offered on a vertical screen. After having been trained to single stripes or equidistant stripe patterns, which were orientated by α + = 45° to the horizontal, the bees had to discriminate between the training direction α + and the competition direction α c = 135° by means of special stripe configurations. These transfer patterns were obtained by varying different stimulus parameters of the original training stripes, for example by (1) reversing contrast between a stripe and the surrounding visual field, (2) changing the ratio of length/width and by this the dimensions of the stripe, and (3) inserting white intervals into the black stripes. In all three test series the bees succeeded in detecting the α +-direction along a broad range of stimulus variations. As the bees in the transfer tests positively responded to patterns, which on the other side were significantly discriminated from the training pattern (control tests), the information about the direction of the visual cue had been transferred to a new pattern configuration never seen by the bees during the training situation. This ability to generalize visual stimuli enables the bees to recognize distinct stimulus characteristics, even when other stimulus properties of a special pattern are changing during time. Secondly, small differences due to one stimulus parameter can be detected in transfer patterns, when the ‘attention’ of the central nervous system has been shifted towards that parameter by previous training. For example, better performances in visual goniometry by means of short stripes are obtained, when the bees had been trained to an especially inclined long stripe than to the short test stripe itself. The effect of ‘training along a continuum’ is thus demonstrated in arthropods for the first time. Although insects were thought only to possess rigidly fixed action patterns, the ability to generalize visual stimuli proved more complex recognition processes, which until now have been mostly found in higher vertebrates.