Stimulus-response System Research Articles

Artificial Intelligence Stimulus Response System

The Stimulus Response System (SRS) is based on the concept of artificial intelligence (AI) based mark-up language. (AIML) and is used to train the system for recognizing the user input. By making use of the previously built knowledge base this system is trying to analyze the user input and it provides the response. The Chatter Bot’s, reported in the literature, and was used mainly the indexing technique. The method is strongly dependent on the contents that are stored in a file or a database. Thus there is a need to develop a new system that allows you to carry on conversations with the system as long as possible. Stimulus Response System creates and adds knowledge to a computer. As a result, the computer will appear as human. The main objective of the work is to design an interactive software package which make the computer simple by building content that induces the client to carry on interactive conversations with the system as long as possible.

In Vivo Laser-Induced Vasoactive Microenvironmental Setting via a Stimuli-Responsive Microstructured Depot.

A stimuli-responsive polymeric three-dimensional microstructured film (PTMF) is a 3D structure with an array of sealed chambers on its external surface. In this work, we demonstrate the use of PTMF as a laser-triggered stimulus-response system for local in vivo targeted blood vessels stimulation by vasoactive substances. The native vascular networks of the mouse mesentery were used as model tissues. Epinephrine and KCl were used as vasoactive agents that were sealed into individual chambers upon precipitation in the amount of pictograms. We demonstrated the method for non-damaged one-by-one chamber activation using a focused 532 nm laser light passed through biological tissues. To avoid laser-induced photothermal damage to biological tissues, the PTMF was functionalized with Nile Red dye, which effectively absorbs laser light. Chemically stimulated blood vessel fluctuations were analyzed using digital image processing methods. Hemodynamics changes were measured and visualized using the particle image velocimetry approach.

Using carbonized hybrid FeNPs@ZIF-8 for the sustained release of doxorubicin hydrochloride

Controlling the slow release of drugs in carriers and reducing environmental pollution and damage from antibiotics is important and challenging research. In this paper, a novel composite material of carbonized FeNPs@ZIF-8 (C-Fe3O4 @ZIF-8) was used to load and release doxorubicin hydrochloride (DOX). Compared with conventional ZIFs materials, greatly enhancing the magnetic properties, drug loading capacity and controlled drug release of the carrier agent. Interestingly, by establishing a dual stimulus response system with environmental factors of pH and temperature, results showed release rate of 61.6 % at a pH of 3 and a temperature of 37 °C. In addition, the SEM-EDS results showed that the surface of C-Fe3O4 @ZIF-8 was partially broken but maintained a stable morphology before and after release. Meanwhile the nitrogen absorption desorption curve (BET) and hysteresis loop reveal that C-Fe3O4 @ZIF-8 can maintain a large specific surface area and a magnetization intensity of 12.4 emu g−1 after release. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR), on the other hand, reveal the presence of partial ligand and hydrogen bond breaks during the release of DOX from DOX-loaded C-Fe3O4 @ZIF-8. Finally, the release of DOX from C-Fe3O4 @ZIF-8 at different pH and temperature is consistent with the Higuch and Bhaskas models, where the latter dominates and proposes a release mechanism. Therefore, the magnetic composite C-Fe3O4 @ZIF-8 in this study has great potential for DOX to effectively control drug release and targeted cancer therapy.

Artificial stimulus-response system capable of conscious response.

A stimulus-response system and conscious response enable humans to respond effectively to environmental changes and external stimuli. This paper presents an artificial stimulus-response system that is inspired by human conscious response and is capable of emulating it. The system is composed of an artificial visual receptor, artificial synapse, artificial neuron circuits, and actuator. By incorporating these artificial nervous components, a series of conscious response processes that markedly reduces response time as a result of learning from repeated stimuli are demonstrated. The proposed artificial stimulus-response system offers the promise of a new research field that would aid the development of artificial intelligence-based organs for patients with neurological disorders.

The pH and mercury ion stimuli-responsive supramolecular assemblies of cucurbit[7]uril and Hoechst 33342

In the present work, we have investigated the effect of pH and mercury ions on the host–guest complex formed between cucurbit[7]uril (Q[7]) and Hoechst 33342 (H33342). 1H NMR, UV–vis and fluorescence spectroscopy revealed that acid/base stimulation could change the binding stoichiometry between Q[7] and H33342. The results suggest that two complexation equilibria (1:1 and 2:1) may exist between H33342 and Q[7] at pH 2.0 and 4.5, respectively. However, a 1:1 host–guest complex was formed between H33342 and Q[7] at pH 7.0 and 10.0. Q[7] shows differential affinities for the protonated and neutral forms of H33342 dye. Moreover, the switching between H33342∙2H+@2Q[7](1:2) at pH 4.5 and H33342∙H+@Q[7](1:1) at pH 7.0 was reversible. Furthermore, as a metal stimulus, Hg2+ ions could push (i) Q[7] from the piperazine ring to the benzimidazole position with a 1:1 guest–host ratio and (ii) a second Q[7] onto the ethyl position with a 1:2 guest–host stoichiometry. This stimulus response system will have potential applications in the field of molecular switch design.

Enhanced modulation of magnetic field on surface plasmon coupled emission (SPCE) by magnetic nanoparticles

The obvious enhancement effect of magnetic nanoparticles (MNPs) introduced in Cr/Co/Cr/Au substrate on the pulsed magnetic field-modulated surface plasmon coupled emission (SPCE) was investigated, and the observed enhancement factor was 4 comparing with the magnetic field modulated SPCE without MNPs. This is the new observation for the magnetic field modulated SPCE, and this method was designed as a biosensor, which to our knowledge, is the first application of magnetic field-modulated SPCE in biosensing and detection field. This strategy is a universal approach to increase the fluorescence signal and helps to build the new SPCE based stimulus-response system.

PH-responsive release of chlorhexidine from modified nanoporous silica nanoparticles for dental applications

Abstract A pH-sensitive stimulus-response system for controlled drug release was prepared by modifying nanoporous silica nanoparticles (NPSNPs) with poly(4-vinylpyridine) using a bismaleimide as linker. At physiological pH values, the polymer serves as gate keeper blocking the pore openings to prevent the release of cargo molecules. At acidic pH values as they can occur during a bacterial infection, the polymer strains become protonated and straighten up due to electrostatic repulsion. The pores are opened and the cargo is released. The drug chlorhexidine was loaded into the pores because of its excellent antibacterial properties and low tendency to form resistances. The release was performed in PBS and diluted hydrochloric acid, respectively. The results showed a considerably higher release in acidic media compared to neutral solvents. Reversibility of this pH-dependent release was established. In vitro tests proved good cytocompatibility of the prepared nanoparticles. Antibacterial activity tests with Streptococcus mutans and Staphylococcus aureus revealed promising perspectives of the release system for biofilm prevention. The developed polymer-modified silica nanoparticles can serve as an efficient controlled drug release system for long-term delivery in biomedical applications, such as in treatment of biofilm-associated infections, and could, for example, be used as medical implant coating or as components in dental composite materials.

Japanese encephalitis virus upregulates the expression of SOCS3 in mouse brain and Raw264.7 Cells.

Japanese encephalitis virus (JEV) is one of the pathogens that can invade the central nervous system, causing acute infection and inflammation of brain. SOCS3 protein plays a vital role in immune processes and inflammation of the central nervous system. In this study, Raw264.7 cells and suckling mice were infected with JEV, and SOCS3 expression was analyzed by the gene expression profile, semiquantitative RT-PCR, qRT-PCR, immunohistochemistry (IHC) and Western blot. Results indicated that 520 genes were found to be differentially expressed (fold change ≥ 2.0, p < 0.05) in total. The differentially regulated genes were involved in biological processes, such as stimulus response, biological regulation and immune system processes. JEV early infection could induce SOCS3 expression, upregulating both the mRNA and protein levels in Raw264.7 cells in a time-dependent manner. The SOCS3 expression was much lower in Raw264.7 cells infected with inactivated JEV than wild-type JEV. In vivo, SOCS3 protein was also found to upregulate the expression of mRNA and protein in JEV-infected mouse brain. Taken together, our data showed that JEV early infection could induce the upregulation of SOCS3 expression, both in vitro and in vivo, providing the basic theoretical foundation for future research on the invasion mechanism of JEV.

Plant Stress and Biotechnology

Plant Stress and Biotechnology

Tansley Review No. 86 Accumulation of phytoalexins: defence mechanism and stimulus response system.

Phytoalexin synthesis is a defence-response- that is characterized by a requirement for a number of distinct elements, all of which must be present for the response to be expressed fully. These same elements: a signal, a cellular receptor, a signal transduction system and a responsive metabolic system, are also used to describe a stimulus-response system. A number of molecular species can function as signal molecules or elicitors of phytoalexin synthesis, including poly- and oligosaccharides, proteins and polypeptides, and fatty acids. Few receptors for elicitors have been identified but those that have been are proteins located on the plasma membrane of the plant. Induction of phytoalexin synthesis involves selective and co-ordinated activation of specific defence response genes, including those encoding the enzymes of phytoalexin synthesis, and these genes constitute the responsive metabolic system. The separate, and distant, locations of the receptor and the responsive genes means that the event in which the signal is perceived by the receptor must be relayed to the genes by means of a second messenger system. Several second messengers are candidates for such a coupling- or signal transduction-system, including udenosine-3',5'-cyclic monophosphate, Ca2+ , diacylglycerol and inositol 1,4,5-trisphosphate, active oxygen species and jasmonic acid. Each has been examined as a possible component of the signal transduction system mediating between the elicitor receptor interaction and the phytoalexin synthesis it induces. Analysis of the signalling events is made complex by the simultaneous solicitation by the invading micro-organism of several defence responses, each of which might involve elements of a different signal system. The same complexity is evident which the role of phytoalexin accumulation in resistance is analysed. Evaluation of the contribution made by phytoalexin accumulation towards resistance has been attempted by the use of various inhibitors and enhancers of the process. Transgenic and mutant plants with specific alterations in one or more ot those elements necessary for the plant to respond to the signals for phytoalexin synthesis and other defence responses, are beginning to aid resolution of the complex pattern ot signalling events and the respective roles of the inducible defence mechanisms in resistance. CONTENTS Summary 1 I. Introduction 2 II. Chemistry of phytoalexins 3 III. Phytoalexin accumulation as a determinant of resistance 6 IV. Elicitation of phytoalexin accumulation 11 References 34.

The use of lanthanum to delineate the aluminium signalling mechanisms functioning in the roots of Zea mays L.

Controlled environment studies involving the treatment of intact roots with Al (5 mg/dm 3) and La 3+ (25 mg/dm 3) have identified some notable similarities in the early reactions by primary roots to these ions. These included root growth inhibition, changes in cap size and construction as well as a marked decline in cap secretory activity. The effects of La 3+ nevertheless appeared to be less damaging to the root than comparable Al treatments (shorter lag periods and faster growth rates). Moreover, roots subjected to “continuous” La 3+ treatments resumed growth with times ⩾ 6 days whereas roots subjected to “continuous” Al treatment did not. These similarities and differences in the response of root cells to La 3+ and Al are discussed with a view to the possible development of La 3+ as an ultrastructural tracer for Al. Roots which had previously been treated with La 3+ or Al but which received Ca 2+ during the recovery phase resumed growth during the course of the experiment (8 days). In contrast Ca 2+ deprivation of roots initially subjected to Al or La 3+ treatments delayed and in some cases prevented recovery. The effects of Ca 2+ deprivation on the stages involved in recovery are discussed in relation to identifying an external (apoplasmic) Ca 2+ requirement which influences the activity of the root cap and mediates the reversal of growth inhibition attributed to the effects of La 3+ and Al. The requirement for an exogenous Ca 2+ supply is combined with data pertaining to Al- and La 3+-induced ultrastructural changes in the apoplasm of peripheral root cap cells to identify components of a stimulus-response system functioning in the root which is responsive to La 3+ and Al. Changes in La 3+- and Al-treated roots deprived of Ca 2+ during recovery also coincided with a re-orientation of shoot growth. These effects are considered in relation to a possible external requirement, by the root, for Ca 2+ which interacts with an endogenous programme involved in modulating shoot expansion and development.

Fetal, hormonal and experiential factors influencing the mating-induced regulation of infanticide in male house mice

When a male house mouse encounters a neonate he either attempts to kill it or he does not harm it. An unusual aspect of his response is that adaptive, time-dependent changes in behavior toward pups result from a unique stimulus-response system triggered specifically by ejaculation. In virgin male CF-1 mice, about 50% of all males are spontaneously infanticidal when they encounter a pup while the other 50% are typically “parental.” The stimulus of ejaculation causes virtually all males to kill pups; however, by the time offspring are born three weeks after mating, infanticide is inhibited and almost all males now behave parentally toward pups. Our experiments examine fetal, experiential, and hormonal factors influencing the changes in infanticidal and parental behavior that occur in male mice as a result of mating. Males who developed in utero between two female fetuses, and were thus exposed to relatively low testosterone concentrations during fetal development, were significantly more likely to exhibit infanticide—both before and after mating—than were males who developed between two male fetuses. Concurrent exposure to testosterone appears required in order for naive males to exhibit infanticide and for spontaneously parental males to become infanticidal after ejaculation. In contrast, neither testosterone nor pituitary hormones appeared responsible for the timed inhibition of infanticide occurring by three weeks after mating, since castrated and hypophysectomized males showed a response pattern similar to intact males. The mating-induced inhibition phenomenon appears to be a neurally timed and mediated response that operates independently from pituitary hormone secretions or changes in gonadal hormones resulting from mating.

Successive 3 H and 14 C Labeling of DNA in a Stimulus-Response System

Quiescent (G0) cells of the central zone region of the rat lens epithelium were recruited into the cell cycle by a wound stimulus. Cells were pulsed with labeled DNA precursor at several different times after the initiation of the DNA synthesis response to wounding and allowed to progress into the mitotic phase. Analysis of mitotic figures resulted in PLM (percentage labeled mitoses) curves that indicated a G2 duration of about 6 h. Double isotopic labeling ([3H]thymidine followed by [14C]thymidine) was utilized to demonstrate the completion of DNA synthesis in earliest responders. Cells completed DNA synthesis in less time (3-5 h) than reflected by the approximately 8-h widths of PLM curves. This discrepancy is attributed to the uptake and retention of labeled precursor by the stimulus-responsive cells while they are still in a pre-S phase condition. Based on a comparison of transit times through G2 and of labeling times to midpoint appearances of labeled mitotic figures, earlier responders do not appear to have faster rates of cell cycle progression than cells responding 2-4 h later. G2 transit time is also comparable for central zone lens cells responding to the relatively strong stimulus of wounding and for the nonperturbed cells previously studied in the germinative zone of the lens epithelium.

Gap junctions and impulse propagation in embryonic epithelium of Amphibia. A freeze-etching study.

Epithelium of amphibian embryos (Cynops orientalis, Xenopus laevis) was found in preceding experiments to generate and conduct impulses during a limited stage (26-37) of development . In order to elucidate the structural basis of impulse propagation, epithelial cells of four stages were examined by the freeze-etching method: (I) before and (II) during acquisition of conductivity; (III) when propagation was fully established, and (IV) when it was no longer present. Only few gap junctions (GJ) of small size were found in groups I and IV. GJ in epithelia of group III were increased in number and size, and appeared morphologically "coupled", i.e., with more loosely arranged connexons. the size of gap-junctional particles did not differ significantly between coupled and uncoupled stages. Zonulae occludentes seemed "leaky" in stage *, and "tight" in stages II-IV. Thus, the morphological characteristics of specialized junctions between "non excitable cells" correlated with the opening and closing of low resistance intercellular current pathways during embryonic development. Gap junctions in particular seem to form an essential link in the non-neural stimulus-response system, which may facilitate the mobility of the embryo during early phases of aquatic life before the reflex pathways have been established. Coupling and uncoupling of gap junctions may also play an important role in the regulation of cell differentiation and morphogenetic movement. The experimental model used in this study provides a useful tool for further investigations of structural correlates of gap junctional permeability under physiological conditions.

INHIBITION OF OVULATION IN THE RABBIT BY ACTINOMYCIN D.

IN the rabbit, an induced ovulator, sufficient gonadotropin is released in the first hour after coitus to result in ovulation 9 h later1. This represents an interesting example of a stimulus-response system. Although the stimulus pathway has been reasonably elucidated, the response is not well understood. The subsequent steps in the response beyond the level of release of gonadotropin, involving interaction of hormone and ovary and culminating in rupture of the Graafian follicle, are unknown. For about 8 h after the coital stimulus the only apparent change in the follicle is an increased protuberance of the follicle above the surface of the ovary. It is during the 2 h prior to rupture of the follicle that a rapid increase in volume occurs. The increased volume is followed by stigma formation, usually at the apex of the follicle, and finally the release of the ovum.

WOUNDS AND THE POLARITY OF IMPLANT-INDUCED ACCESSORY URODELE LIMBS.

PREVIOUS work1–3 has established that xenoplastic implants made into the limbs of larval and adult urodeles would initiate the formation of accessory limb structures and, further4, that the position of the superficial wound used for insertion of the implanted material seemed to have a very decided effect on the stimulus-response system. The implants would not take advantage of wounds made proximal to the implant so readily as they would of distal wounds. In larvae, as well as adults, very few growths were produced from proximal wound areas. These few supernumerary limbs which did form in association with proximal wounds, however, showed interesting growth patterns which are better understood to-day than they were at the time of the previous writing.