Positional estimation techniques for an autonomous mobile robot

Techniques for positional estimation of a mobile robot navigation in an indoor environment are described. A comprehensive review of the various positional estimation techniques studied in the literature is first presented. The techniques are divided into four different types and each of them is discussed briefly. Two different kinds of environments are considered for positional estimation; mountainous natural terrain and an urban, man-made environment with polyhedral buildings. In both cases, the robot is assumed to be equipped with single visual camera that can be panned and tilted and also a 3-D description (world model) of the environment is given. Such a description could be obtained from a stereo pair of aerial images or from the architectural plans of the buildings. Techniques for positional estimation using the camera input and the world model are presented

Trust and Technologies: Implications for Information Technology Supported Work Practices

In this paper we empirically investigate the concept of trust using organizational work practices in three groups: within the team, between teams and when interacting with technology. This study adopts Repertory Grid methodology as an interview based technique to elicit important constructs of trust to team members working in two organizations within the energy distribution industry. Thirteen key constructs of trust were identified using content analysis. Drawing on the understanding gained, this paper discusses the implications for theories on trust within teams working with information technology and provides a grounded perspective that could be used as a basis for further research

View-Invariant Regions and Mobile Robot Self-Localization

This paper addresses the problem of mobile robot self-localization given a polygonal map and a set of observed edge segments. The standard approach to this problem uses interpretation tree search with pruning heuristics to match observed edges to map edges. Our approach introduces a preprocessing step in which the map is decomposed into 'view-invariant regions' (VIRs). The VIR decomposition captures information about map edge visibility, and can be used for a variety of robot navigation tasks. Basing self-localization search on VIRs greatly reduces the branching factor of the search tree and thereby simplifies the search task. In this paper we define the VIR decomposition and give algorithms for its computation and for self-localization search. We present results of simulations comparing standard and VIR-based search, and discuss the application of the VIR decomposition to other problems in robot navigation

Role of adenylate cyclase, guanylate cyclase enzyme and phosphodiesterase isozyme modulation in animal models of epilepsy

INTRODUCTION : Epilepsy is defined as a group of disorders of central nervous system (CNS) characterized by paroxysmal cerebral dysrhythmia, manifesting as brief episodes (seizures) of loss or disturbances of consciousness with or without characteristic body movement (convulsion), sensory or psychiatric phenomena. Epilepsy is the third most common neurological disorder affecting the world wide population. In which, the cyclic adenosine 3',5'- monophosphate (cAMP) plays a major role in the generation of seizure activity. The adenylate cyclase, an important transmembrane enzyme possesses certain activity in the brain, which promotes the intracellular level of cAMP, from adenosine triphosphate (ATP). An elevation in cAMP content has been reported in the cerebral cortex accompanying chemically induced epileptic activity Cyclic AMP plays a key function by controlling a wide variety of cellular processes, also which acts as a ubiquitous second messenger and modulator of signal transduction processes. This cAMP is generated by the action of adenylyl cyclase and degraded by hydrolysis process, which is regulated by a family of cyclic nucleotide phosphodiesterases (PDEs) . The neuronal cell signaling structure of cytoskeleton plays a vital role in the development of seizures. Cyclic nucleotides have been extensively studied as second messengers of intracellular events initiated by activation of many types of hormone and neurotransmitter receptors. Cyclic guanosine monophosphate (cGMP) also serves as a second messenger in a manner similar to that observed with cAMP. Peptide hormones, such as natriuretic factors, activate receptors that are associated with membrane bound guanylate cyclase (GC). Receptor activation of GC leads to the conversion of GTP to cGMP. Nitric oxide (NO) also stimulates cGMP production by activating soluble GC, perhaps by binding to the heme moiety of the enzyme. Similar to cAMP, cGMP mediates most of its intracellular effects through the activation of specific cGMP dependent protein kinases (PKG). Several families of PDEs act as regulatory switches by catalyzing the degradation of cGMP to guanosine -5-monophosphate (5-GMP). AIMS : To examine and investigate the possible roles of specific inhibitors of PDE along with adenylate cyclase inhibitor, soluble guanylate cyclase activator and inhibitor in the generation of convulsive seizures. Identification and investigation of new cGMP mediated phophodiesterase family members will offers a new strategy for improvement of brain function and for the new therapy for epilepsy in future. To examine and investigate the role of different ion channel modulator in the generation of convulsive seizures. OBJECTIVES : A family of cyclic nucleotide PDEs used to regulate the process of cAMP generation and degradation by hydrolysis with the action of adenylyl cyclase activators and inhibitors. Cyclic AMP plays a key task by controlling a wide variety of cellular processs, also an elevation of cAMP content has been reported in the cerebral cortex associated with chemically induced epileptic activity. Apart from cAMP, cGMP also possess certain intracellular effects through the activation of specific cGMP dependent protein kinases (PKG) by way of soluble guanylate cyclase (sGC). In view of these findings the present study was undertaken to examine and investigate the possible roles of specific inhibitors of PDEs along with adenylate cyclase inhibitors, soluble guanylate cyclase activator and inhibitors to evaluate the effect on chemical convulsant and maximal electroshock induced seizures in mice and rats. Ion channels mediate and regulate crucial electrical functions throughout the body. They are therapeutic drug targets for a variety of disorders and the direct cause of unwanted side effects. In the view of these principles the present study also designed to examine and investigate the role of different ion channel modulator such as sodium channel modulator, calcium channel modulator, blocker and activator in the generation of convulsive seizures. MATERIALS AND METHODS : Rolipram, Cilostazol, SQ 22536, A-350619, Methylene blue, Pentylenetetrazole or metrazol (PTZ), Picrotoxin (PTx), Kainic acid and 10 % w/v Dimethyl sulfoxide (DMSO) were obtained from Sigma chemical Co.(St.Louis, MO, USA), Dipyridamole, BRL-50481 and Etazolate were bought from Tocris Bioscience (UK), Zonisamide and Sildenafil were obtained from Sun Pharma (Mumbai, India), Amrinone was bought from Samarth Pharma (India), Milrinone was obtained from Sanofi Synthelab Ltd (Mumbai, India), Gabapentin was purchased from Micro labs Ltd. (Bangalore, India), Lacosamide was bought from Cayman Chemicals (USA), Amiloride was obtained from Micro Nova Pharmaceuicals (Bangalore, India), Amiodarone was purchased form Zydus Alidac (Ahemedabad, India), Flecainide was obtained from Shreeji Pharma International, (Gujarat, India), Nifedipine was purchased from Bayer India Ltd (Mumbai, India), Bay K8644 S(-) was bought from Santa Cruz Biotechnology Inc. (USA), Isoniazid (INH) was obtained from Fourts India Ltd (Chennai, India), Pilocarpine was bought from FDC Limited, (Mumbai, India), Normal saline (0.9 %) received from CMC (Vellore, India), Sterile water for injection was obtained from Nirmal Prime Health Care (Mumbai, India), Electro Convulsiometer (Techno, India). The selection of dose for all drugs and pharmacological tools for the animal models of epilepsy were based on the previous research work. The route of administration of almost all the drugs and chemicals were intra peritoneal (i.p). Statistical Analysis : All the datas were expressed as mean ± SEM. The statistical analysis were carried out by one way analysis of variance (ANOVA) followed by Dunnett’s test as well as Tukey-Kramer Multiple Comparisons Test using Graphpad Instat version 3. Statistically significant difference was ascertained by ‘P’ value which is considered significant at the level of P<0.05 and highly significant at P<0.001. CONCLUSION : Thus in conclusion, phosphodiesterase(PDEs) ioszymes regulate the degradation of cyclic GMP and cAMP a product of the guanylate cyclase and adenylate cyclase activation and could contribute to the pathophysiology of the seizure mechanisms. PDE enzymes are responsible for the hydrolysis of the cyclic nucleotides and therefore have a critical role in regulating intracellular levels of the second messengers cAMP, cGMP, and hence cell function as well as downstream cell signalling in the various body systems. Recent evidence that the cyclic nucleotide phosphodiesterases exist in several molecular forms and that these isozymes are unequally distributed in various tissue. Clinical signs of epilepsy arise from the intermittent, excessively synchronized activity of group of neurons. Different neurotransmitters and neuro-modulators are known to play a significant role in the system of excitation. As per our study results, PDE inhibitors works as a proconvulsant, so phosphodiesterase (PDEs) isozymes might used as anticonvulsant molecule for better therapeutic response in future

Role of adenylate cyclase, guanylate cyclase enzyme and phosphodiesterase isozyme modulation in animal models of epilepsy

Epilepsy is a generally a chronic neurological disorder. Neither an effective prophylaxsis nor a permanent cure of any of these disorders is available except neurosurgical resection of epileptic tissue in selected instances. There is hope that understanding the cellular and molecular mechanisms of the epilepsies will lead to improved therapies as well as new insights into brain structure and function. Because of the inherent diversity of the epilepsies and their models and the wide range of techniques used for investigating their cellular and molecular basis, I had focused on selected models and issues, attempted to bring some coherency to the findings, and sought to draw conclusions that may be generally relevant to epilepsy. I made a special effort to show how investigations of the epilepsies with methods from diverse disciplines can be complementary and mutually reinforcing. By use of the tools of electrophysiology it was initially demonstrated that the epilepsies are disorders of neuronal excitability, which were subsequently characterized in populations of neurons, in individual neurons, and single ion channels. Next, I addressed the cellular mechanisms of seizures. Finally, I present ways of utilizing PDE inhibitors for the study of epilepsy in animals. PDE-3 inhibitors related study shows a definite relationship between the specific PDE-3 inhibitors and increase the cellular level of cGMP and Ca2+ ions with the generation of seizures. The releases of free radicals have been implicated in many drug and chemical induced toxicities. It is possible that increased production of reactive oxygen species could result in oxidant/ anti-oxidant imbalance and thus, precipitate neurotoxicity. Therefore it appears that non nucleotide mechanism although not well defined could also be contributing significantly to the seizure activity of phosphodiesterase 3 inhibitors. The present study finds that PDE-5 inhibitor, sildenafil having strong proconvulsant activitsy in MES and INH induced animal models of epilepsy and also PDE-3 & 4 inhibitors, such as cilostazol and rolipram possess less pro-convulsant action. The probable mode of action may be the cGMP levels elevated by certain excitatory amino acids and may allow one to imply that an excitable state exists in the neuronal cells through the action of the G-protein as well as the ion channel. Although the findings here seem to indicate divergent features of the excitable neuronal cells, they may provide clues to observing a close association of receptors, enzymes and channels of the membranes in exploring the provocation of seizures. The present study reflects the individual effect of adenylate cyclase (AC) inhibitor, SQ22536 delay the onset of action of seizures as well as prolonging the total duration of convulsive time in both PTZ and MES models of epilepsy. The SQ22536 greatly increased the anti-convulsant activity along with higher percentage protection range of animals in both models of epilepsy. Further studies can be conducted using specific neuronal cell lines and elucidating the exact signal transduction mechanisms responsible for anti-convulsant effects. The study reflects, (i) the individual effect of guanylate cyclase (GC) inhibitor, methylene blue delays the onset of action of seizures as well as prolong the total duration of convulsive time in both PTZ and MES models of epilepsy. The methylene blue greatly increased the anti-convulsant activity along with higher percentage protection range of animals in both models of epilepsy; (ii) onset of action and the incidence of seizures are quick in sGC activator, A-350619 alone as well as combination with PDE-7 inhibitor, BRL-50481 treated groups; (iii) the occurrence of high percentage of mortality is associated with quick onset of seizures resembles pro-convulsant action in A-350619 alone as well as combination with BRL-50481 treated groups in both animal models of epilepsy; (iv) This study also reflects the identification and investigation of new cGMP mediated phosphodiesterases family members will offers a new strategy for improvement of brain function and for the new therapy for epilepsy in future. Sodium channel modulators such as amiloride and flecainide having more distinct role in the generation of delay onset of seizures in all the phases of convulsion while compared to calcium channel modulator alone treated group. This result reflects the SCM having more potency of anti-convulsant activity while compared to CCM. The combination of SCM along with CCM also enhances the delay onset of seizures when compared to CCM alone treated group. This indicates SCM having more potency of anticonvulsant activity. The animals which exposed increase the anti-convulsant activity while increase the dose levels of SCM even with different chemo convulsants like PTZ and picrotoxin (PTX). Calcium channel blocker and activator related study explained that delay in onset of various phases of convulsion in both models was enhanced by calcium channel blocker (amiodarone) alone treated animals. This shows that CCB having anti-convulsant activity. The difference in onset of time of various phases of convulsion was clearly explained with help of calcium channel activator [Bay K8644, S (-)], which enhances the quick onset of convulsive threshold. So, Bay K8644, S (-)] possess proconvulsant activity. The data explains that methylene blue alone, methylene blue with BRL50481 greatly increased the anti-convulsant activity along with higher protection range of animals were seen in both models. The study also explains that the combination of A-350619 with BRL50481 as well as the individual effect of A-350619 and BRL 50481 alone showed a quick onset of seizures response with increased the mortality range in both animal models of epilepsy. The combination of sGC inhibitor, methylene blue with etazolate showed a delay onset of seizures, compared to other groups. This confirms that sGC inhibitor having anti-convulsant activity. The study also demonstrates that etazolate alone and etazolate in combination with BRL50481 greatly enhances quick onset of seizures. So, this study strongly suggests that etazolate having proconvulsant activity. CONCLUSION: Advances in our understanding of the molecular pharmacology of cyclic nucleotide PDE isozymes have led to the development of first and second generation selective inhibitors for a variety of clinical indications. While it is difficult to predict the extent to which each of these strategies will eventually affect the management of epilepsy, it is clear that exciting times are ahead of us. Thus in conclusion, phosphodiesterase(PDEs) ioszymes regulate the degradation of cyclic GMP and cAMP a product of the guanylate cyclase and adenylate cyclase activation and could contribute to the pathophysiology of the seizure mechanisms. PDE isozymes are responsible for the hydrolysis of the cyclic nucleotides and therefore have a critical role in regulating intracellular levels of the second messengers cAMP, cGMP, and hence cell function as well as downstream cell signalling in the various body systems. Recent evidence that the cyclic nucleotide phosphodiesterases exist in several molecular forms and that these isozymes are unequally distributed in various tissue. Clinical signs of epilepsy arise from the intermittent, excessively synchronized activity of group of neurons. Different neurotransmitters and neuro-modulators are known to play a significant role in the system of excitation. As per our study results, PDE inhibitors works as a proconvulsant, so phosphodiesterase (PDEs) isozymes might used as anti-convulsant molecule for better therapeutic response in future

Full Thermoelectric Characterization of Stoichiometric Electrodeposited Thin Film Tin Selenide (SnSe)

Tin selenide (SnSe) has attracted much attention in the thermoelectric community since the discovery of the record figure of merit (ZT) of 2.6 in single crystal tin selenide in 2014. There have been many reports since of the thermoelectric characterization of SnSe synthesized or manufactured by several methods, but so far none of these have concerned the electrodeposition of SnSe. In this work, stoichiometric SnSe was successfully electrodeposited at −0.50 V vs SCE as shown by EDX, XPS, UPS, and XRD. The full ZT of the electrodeposits were then measured. This was done by both a delamination technique to measure the Seebeck coefficient and electrical conductivity which showed a peak power factor of 4.2 and 5.8 μW m–1 K–2 for the as deposited and heat-treated films, respectively. A novel modified transient 3ω method was used to measure the thermal conductivity of the deposited films on the deposition substrate. This revealed the thermal conductivity to be similar to the ultralow thermal conductivity of single crystal SnSe, with a value of 0.34 W m–1 K–1 being observed at 313 K

Designing an information system for updating land records in Bangladesh: action design ethnographic research (ADER)

Open Access. This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.This article has been made available through the Brunel Open Access Publishing Fund.Information Systems (IS) has developed through adapting, generating and applying diverse methodologies, methods, and techniques from reference disciplines. Further, Action Design Research (ADR) has recently developed as a broad research method that focuses on designing and redesigning IT and IS in organizational contexts. This paper reflects on applying ADR in a complex organizational context in a developing country. It shows that ADR requires additional lens for designing IS in such a complex organizational context. Through conducting ADR, it is seen that an ethnographic framework has potential complementarities for understanding complex contexts thereby enhancing the ADR processes. This paper argues that conducting ADR with an ethnographic approach enhances design of IS and organizational contexts. Finally, this paper aims presents a broader methodological framework, Action Design Ethnographic Research (ADER), for designing artefacts as well as IS. This is illustrated through the case of a land records updating service in Bangladesh

Electrochemically copper-doped bismuth tellurium selenide thin films

We report the first results of a study on electrochemically doped copper bismuth tellurium selenide thin films electrodeposited from aqueous nitric acid electrolytes containing up to 2 mM of Cu(NO3)2. The effect of Cu(NO3)2 concentration on the composition, structure and thermoelectric properties of the bismuth tellurium selenide films is investigated by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and Seebeck and Hall effect measurements. A Cu(NO3)2 concentration of 1.5 mM is found to offer a Seebeck coefficient of up to −390 μV K−1 at room temperature, which is the highest reported to date for an electrodeposited bismuth tellurium compound