Differential impact of COVID-19 on mental health and burnout.

BACKGROUND: There may be differential impact of the COVID-19 pandemic on mental health and burnout rates of healthcare professionals (HCPs) performing different roles. AIMS: To examine mental health and burnout rates, and possible drivers for any disparities between professional roles. METHODS: In this cohort study, online surveys were distributed to HCPs in July-September 2020 (baseline) and re-sent 4 months later (follow-up; December 2020) assessing for probable major depressive disorder (MDD), generalized anxiety disorder (GAD), insomnia, mental well-being and burnout (emotional exhaustion and depersonalization). Separate logistic regression models (at both phases) compared the risk of outcomes between roles: healthcare assistants (HCAs), nurses and midwives (nurses), allied health professionals (AHPs) and doctors (reference group). Separate linear regression models were also developed relating the change in scores to professional role. RESULTS: At baseline (n = 1537), nurses had a 1.9-fold and 2.5-fold increased risk of MDD and insomnia, respectively. AHPs had a 1.7-fold and 1.4-fold increased risk of MDD and emotional exhaustion, respectively. At follow-up (n = 736), the disproportionate risk between doctors and others worsened: nurses and HCAs were at 3.7-fold and 3.6-fold increased risk of insomnia, respectively. Nurses also had a significantly increased risk of MDD, GAD, poor mental well-being and burnout. Nurses also had significantly worsened anxiety, mental well-being and burnout scores over time, relative to doctors. CONCLUSIONS: Nurses and AHPs had excess risk of adverse mental health and burnout during the pandemic, and this difference worsened over time (in nurses especially). Our findings support adoption of targeted strategies accounting for different HCP roles.

THE ROLE OF EXERCISE IN PREVENTING CHRONIC DISEASES: CURRENT EVIDENCE AND RECOMMENDATIONS.

Regular exercise helps to enhance health outcomes and lower risk factors, making it a crucial element in the prevention of chronic diseases. By being physically active, people can improve their general health and delay the onset of a number of chronic illnesses. For understanding the relationship between increased physical activity or decreased physical inactivity and favorable health outcomes, observational studies are the main source of information. We will look for systematic analyses of randomized controlled trials with a main emphasis on outcomes linked to diseases in the Cochrane Database of systematic studies. Evaluation will be limited to those in a few key chronic conditions. Preventing chronic illness and achieving better results in the management or treatment of chronic illness are the main outcomes of interest. For each chronic condition (such as the control of glucose in diabetes or any change in hypertension blood pressure), these results will be summarized and displayed. The design and implementation of chronic conditions, physical exercise illness conditions, and adverse physical activity-related events are of secondary interest. Our findings should help decision-makers, guideline organizations, and academics identify the most effective physical activity programs for major chronic disease management and prevention. Exercise and physical activity (PA) offers a non-invasive approach to the management of chronic disorders. More physiological, biochemical, and molecular data on the positive effects of PA and exercise on health should constitute a primary focus of future studies.

Ultrasound measurement of the distance of the phrenic nerve from the brachial plexus at the classic interscalene point and upper trunk: A volunteer-based observational study.

Background and Aims: The method of blocking the brachial plexus at the level of the upper trunk has been gaining popularity as a phrenic nerve-sparing alternative for interscalene block. We aimed to measure the distance of the phrenic nerve from the upper trunk and compare it with the distance between the phrenic nerve and the brachial plexus at the classic interscalene point by using ultrasound. Method: In this study, after ethical approval and trial registration, 100 brachial plexus of 50 volunteers were scanned from the emergence of the ventral rami and its course was traced to the supraclavicular fossa. The distance of the phrenic nerve from the brachial plexus was measured at two levels: the interscalene groove along the cricoid cartilage (classic interscalene block point) and from the upper trunk. The presence of anatomical variations of the brachial plexus, the classic traffic light sign, vessels across the plexus, and the location of the cervical oesophagus were also noted. Results: At the classic interscalene point, the C5 ventral ramus was observed to be just emerging or to have fully emerged from the transverse process. The phrenic nerve was identified in 86/100 (86%) of scans. The median (IQR) distance of the phrenic nerve from the C5 ventral ramus was 1.6 (1.1-3.9) mm and that of the phrenic nerve from the upper trunk was 17 (12-20.5) mm. Anatomical variations of the brachial plexus, the classic traffic light sign, and vessels across the plexus were seen in 27/100, 53/100, and 41/100 scans respectively. The oesophagus was consistently located on the left side of the trachea. Conclusions: There was a 10-fold increase in the distance of the phrenic nerve from the upper trunk when compared to that from the brachial plexus at the classic interscalene point.

Effect of laser bleaching, ultrasonic scaling and powered tooth brushing on surface roughness and bacterial adherence of class V composite restorations.

Objective: To evaluate and compare the effect of diode laser assisted bleaching, ultrasonic scaling and powered tooth brushing on surface roughness and bacterial adherence on class V cavities restored with composites. Materials and methods: A total of one hundred and twenty samples (40 samples each of Brilliant Everglow, Beautifil II and Heytec-N) were prepared in standardized stainless steel molds. The samples were further subdivided into four subgroups i.e. one control group (without any intervention) and three experimental groups - diode laser assisted bleaching, ultrasonic scaling and powered tooth brushing consisting of 10 sample each. Surface roughness was measured quantitatively with the help of 3D Optical Profilometer. For bacterial adherence analysis S. mutans strain (ATCC 25175) was cultured in BHI medium and samples were evaluated for the presence of viable bacteria using the Colony Forming Unit (CFU) count. Results obtained were then tabulated and subjected to statistical analysis. Results: Diode laser bleaching caused a significant increase in surface roughness and bacterial adherence with lowest mean change exhibited by Heytec-N followed by Beautifil II and highest by Brilliant Everglow group. Similarly, Ultrasonic scaling increased the surface roughness of all the three tested samples with significant difference between the groups. Powered tooth brushing had no effect on the surface roughness and bacterial adherence of the tested composites. Conclusion: Diode assisted laser bleaching and ultrasonic caused significantly higher surface roughness and bacterial adherence values for all the tested composites. It may therefore be recommended to do finishing and polishing of restorations after such procedures.

Lateral diffusion of lipids in the DMPG membrane across the anomalous melting regime: effects of NaCl.

The anionic dimyristoyl phosphatidylglycerol (DMPG) membrane in solvents with a low ionic strength is known to exhibit an unusually wide melting regime between the gel and fluid phase characterized by various anomalous macroscopic characteristics, such as low turbidity and high electrical conductivity and viscosity. A recent neutron spin echo study [Kelley, E. G. et al., Struct. Dyn., 7 (2020) 054704] revealed that during the extended melting phase transition the DMPG membrane becomes softer and exhibits faster collective bending fluctuation compared to the higher temperature fluid phase. In contrast, in the present work, using incoherent quasielastic neutron scattering through the anomalous phase transition regime we find that single-particle lateral and internal lipid motions in the DMPG membrane show regular temperature dependence, with no enhanced dynamics evident in the anomalous melting regime. Further, we find that incorporation of NaCl in DMPG suppresses the anomalous extended melting regime, concurrently enhancing the single-particle lipid dynamics, both the lateral diffusivity and (to a lesser extent) the internal lipid motion. This seems rather counterintuitive and in variance with the dynamic suppression effect exerted by a salt on a zwitterionic membrane. However, since incorporation of a salt in anionic DMPG leads to enhanced cooperativity, the disrupted cooperativity in the salt-free DMPG is associated with the baseline lipid dynamics that is suppressed to begin with, whereas addition of salt partially restores the cooperativity, thus enhancing lipid dynamics compared to the salt-free baseline DMPG membrane state. These results provide new insights into the ion-membrane interaction and divulge a correlation between microscopic dynamics and the structure of the lipid bilayer.

The Contribution of Transpiration to Precipitation Over African Watersheds.

The redistribution of biological (transpiration) and non-biological (interception loss, soil evaporation) fluxes of terrestrial evaporation via atmospheric circulation and precipitation is an important Earth system process. In vegetated ecosystems, transpiration dominates terrestrial evaporation and is thought to be crucial for regional moisture recycling and ecosystem functioning. However, the spatial and temporal variability in the dependency of precipitation on transpiration remains understudied, particularly in sparsely sampled regions like Africa. Here, we investigate how biological and non-biological sources of evaporation in Africa contribute to rainfall over the major watersheds in the continent. Our study is based on simulated atmospheric moisture trajectories derived from the Lagrangian model FLEXPART, driven by 1° resolution reanalysis data over 1981-2016. Using daily satellite-based fractions of transpiration over terrestrial evaporation, we isolate the contribution of vegetation to monthly rainfall. Furthermore, we highlight two watersheds (Congo and Senegal) for which we explore intra- and interannual variability of different precipitation sources, and where we find contrasting patterns of vegetation-sourced precipitation within and between years. Overall, our results show that almost 50% of the annual rainfall in Africa originates from transpiration, although the variability between watersheds is large (5%-68%). We conclude that, considering the current and projected patterns of land use change in Africa, a better understanding of the implications for continental-scale water availability is needed.

Tetravalent SARS-CoV-2 Neutralizing Antibodies Show Enhanced Potency and Resistance to Escape Mutations.

Neutralizing antibodies (nAbs) hold promise as therapeutics against COVID-19. Here, we describe protein engineering and modular design principles that have led to the development of synthetic bivalent and tetravalent nAbs against SARS-CoV-2. The best nAb targets the host receptor binding site of the viral S-protein and tetravalent versions block entry with a potency exceeding bivalent nAbs by an order of magnitude. Structural studies show that both the bivalent and tetravalent nAbs can make multivalent interactions with a single S-protein trimer, consistent with the avidity and potency of these molecules. Significantly, we show that the tetravalent nAbs show increased tolerance to potential virus escape mutants and an emerging variant of concern. Bivalent and tetravalent nAbs can be produced at large-scale and are as stable and specific as approved antibody drugs. Our results provide a general framework for enhancing antiviral therapies against COVID-19 and related viral threats, and our strategy can be applied to virtually any antibody drug.

Data for a city-level health impact assessment of urban transport in Mauritius.

Participatory quantitative Health Impact Assessments (HIAs) in developing countries are rare partly due to data scarcity. This paper reports on primary data collected in the city of Port Louis to complete a HIA of urban transport planning in Mauritius. We conducted a full-chain participatory HIA to assess health impacts on the basis of a transport mode shift in Port Louis, Mauritius [1]. By applying mixed-methods, we estimated averted deaths per year and economic outcomes by assessing the health determinants of air pollution, traffic deaths and physical activity. The participatory quantitative HIA included [1] baseline data collection [2] co-validation of transport policy scenarios with stakeholders and [3] quantitative modelling of health impacts. We used the risk assessment method for HIA appraisal. The data can be reused for epidemiological analysis and different types of impact assessments.

Participatory quantitative health impact assessment of urban transport planning: A case study from Eastern Africa.

BACKGROUND: High rates of motorization in urban areas of Africa have adverse effects on public health. Transport-related mortality will increase as a result of inadequate transport infrastructure, air pollution and sedentary lifestyles. Health Impact Assessments (HIAs) have proven to be a successful tool to predict and mitigate negative health impact of urban transport planning policies, programmes or projects. Yet, there is a gap of evidence on transport and health in African countries. The aim of this study is assessing the health impacts of transport scenarios in Port Louis (city of 119,018 inhabitants in Mauritius) using a full chain participatory HIA model. METHODS: We estimated health and economic impacts associated to transport scenarios with qualitative data and quantitative comparative risk assessment methods. The health impact modeling was based on differences between the baseline and three transport scenarios (worse, good, ideal), estimating the averted deaths per year and economic outcomes by assessing health determinants of air pollution (AP), traffic deaths and physical activity (PA). Data on air pollution and traffic fatalities were obtained from public data sources. Data used to construct scenarios, establish baseline travel mode shares and physical activity were collected through (a) open-ended individual interviews (IDIs) with 14 stakeholders (b) closed-ended survey questions to 600 citizens and (c) 2 focus group discussions (FGDs) with the same 14 stakeholders from (a). RESULTS: In Port Louis, the worse-case transport scenario (doubling in car trips and a reduction in walking, motorcycle, and public transport), resulted in a total increment of 3.28 premature deaths per year. The good-case scenario (reducing car trips by half and increasing walking, motorcycle, and public transport trips) resulted in a total increment of 0.79 premature deaths per year. The ideal-case scenario (reduction in car and motorcycle trips and an increase in walking and public transport trips) resulted in a total reduction of 13.72 premature deaths per year. We estimated USD 23 millions of economic benefits related to mortality if the ideal-case was achieved. CONCLUSION: Participatory HIA shows that implementing transport policies aiming for less than an ideal situation may not be adequate or sufficient to avoid negative transport-related mortality in Mauritius. Urban transport planning is an opportunity to encourage physical activity in rapidly urbanizing settings of Africa. Transport policies should aim to restrict all forms of private motorized vehicles and promote active and public transport to support public health. We highly recommend the use of participatory approaches in quantitative HIA to ensure context specificity and policy relevance.

Tetravalent SARS-CoV-2 Neutralizing Antibodies Show Enhanced Potency and Resistance to Escape Mutations.

Neutralizing antibodies (nAbs) hold promise as effective therapeutics against COVID-19. Here, we describe protein engineering and modular design principles that have led to the development of synthetic bivalent and tetravalent nAbs against SARS-CoV-2. The best nAb targets the host receptor binding site of the viral S-protein and its tetravalent versions can block entry with a potency that exceeds the bivalent nAbs by an order of magnitude. Structural studies show that both the bivalent and tetravalent nAbs can make multivalent interactions with a single S-protein trimer, observations consistent with the avidity and potency of these molecules. Significantly, we show that the tetravalent nAbs show much increased tolerance to potential virus escape mutants. Bivalent and tetravalent nAbs can be produced at large-scale and are as stable and specific as approved antibody drugs. Our results provide a general framework for developing potent antiviral therapies against COVID-19 and related viral threats, and our strategy can be readily applied to any antibody drug currently in development.

Cell proliferation proteins and aggressiveness of histological variants of ameloblastoma and keratocystic odontogenic tumor.

Tumors that originate from the epithelium of the odontogenic apparatus are classified as benign or malignant. The proliferative activity could provide a basis for differences in the biologic behavior among the histological variants of ameloblastoma (AM) and keratocystic odontogenic tumor (KCOT). We examined 32 solid AM and 18 KCOT cases. The AM sample comprised 16 cases of follicular AM, six cases of unicystic AM, eight cases of plexiform AM and two cases of acanthomatous AM. Sections were stained with the Ki-67 antibody. Ten representative fields were selected randomly in each section. For AM, peripheral tall columnar cells of tumor islands/nests/cords were selected. For KCOT, fields were selected in the basal and the suprabasal region of the epithelial lining. We counted the average number of Ki-67 positive cells/field for AM and KCOT. AM exhibited Ki-67 expression in peripheral tall columnar cells, whereas KCOT exhibited Ki-67 expression in the basal and suprabasal layer. No significant difference between AM and KCOT was observed; the cellular proliferative activity varied among the subtypes. No significant difference in Ki-67 expression in acanthomatous, cystic and follicular types of AM was observed, although the plexiform type exhibited significantly higher levels than the other three types. High expression of Ki-67 could be a useful prognostic marker for proliferative activity and a prognostic indicator for recurrence rate of AM and KCOT.

Temporally local recurrent radial basis function network for modeling and adaptive control of nonlinear systems.

In this paper, a novel temporally local recurrent radial basis function network for modeling and adaptive control of nonlinear systems is proposed. The proposed structure consists of recurrent hidden neurons having weighted self-feedback loops and a weighted linear feed-through from the input layer directly to the output layer neuron(s). The dynamic back-propagation algorithm is developed and used for updating the parameters of the proposed structure. To improve the performance of learning algorithm, discrete Lyapunov stability method is used to develop an adaptive learning rate scheme. This scheme ensures the faster convergence of the parameters and maintains the stability of the system. A total of 5 complex nonlinear systems are used to test and compare the performance of the proposed network with other neural network structures. The disturbance rejection tests are also carried out to check whether the proposed scheme is able to handle the external disturbance/noise signals effects or not. The obtained results show the efficacy of the proposed method.

Tuberculosis diagnostic and treatment practices in private sector: Implementation study in an Indian city.

SETTING: Implementation study in private health facilities in an Indian metropolis. OBJECTIVES: Improve Tuberculosis (TB) care by private practitioners (PPs). METHODS: PPs from a defined city area were imparted short training in TB care and linkages made with public facilities; subsequent practices were recorded. RESULTS: Of 364 presumptive TB patient records, 70 (19.3%) did not conform to its definition. Of the conforming, 174 (59.2%) had presumptive pulmonary TB (PTB), 53 (18%) presumptive extra-pulmonary (EPTB) and 67 (24%) had both. Of conforming presumptive PTB, most underwent Chest X-ray and sputum examination in private laboratories. Tissue based diagnostics were not advised for most presumptive EPTB patients. Of 101 cases diagnosed with TB, 82% were new, 23% known diabetic and 4.7% human immune deficiency virus (HIV) reactive out of 64 tested. Most were notified and initiated treatment within 15 days of diagnosis. One-fourth was prescribed standard treatment regimen and treatment was not directly observed for most. One third was initial defaulters or lost during treatment; 62% of PTB and 46% EPTB cases initiated on treatment in private were successfully treated. Of successfully treated PTB cases, 61% had undergone follow-up sputum examination. CONCLUSION: Much intensified support mechanisms are needed to improve TB care in private sector.

Knowledge of private practitioners of Bangalore city in diagnosis, treatment of pulmonary tuberculosis and compliance with case notification.

One hundred and twenty-nine qualified private practitioners (PPs) were assessed on their knowledge in diagnosis of pulmonary tuberculosis (PTB), treatment of a new drug sensitive PTB case and practices of case notification, using semi-structured questionnaire. About 20% had adequate knowledge of diagnosis, 29% of treatment regimen, 54% the need for Direct Observation Treatment and 57% about role of sputum smear examination in monitoring treatment response. Of 85 (68%) PPs who had diagnosed any TB case during last two years, 54 (64%) had practised notification. These findings suggest the need for upgrading knowledge of PPs in TB diagnosis, treatment and notification.

Involvement of atrial natriuretic peptide in abrogated cardioprotective effect of ischemic preconditioning in ovariectomized rat heart.

BACKGROUND: Nitric oxide (NO) is an effective mediator of ischemic preconditioning (IPC)-induced cardioprotection. Atrial natriuretic peptide (ANP) is downregulated after ovariectomy, which results in reduction in the level of NO. The present study deals with the investigation of the role of ANP in abrogated cardioprotective effect of IPC in the ovariectomized rat heart. METHODS: Heart was isolated from ovariectomized rat and mounted on Langendorff's apparatus, subjected to 30 min of ischemia and 120 min of reperfusion. IPC was given by four cycles of 5 min of ischemia and 5 min of reperfusion with Krebs-Henseleit solution. The myocardial infract size was estimated employing triphenyltetrazolium chloride stain, and coronary effluent was analyzed for creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) release to consider the degree of myocardial injury. The cardiac release of NO was estimated by measuring the level of nitrite in coronary effluent. RESULTS: IPC-mediated cardioprotection was significantly attenuated in ovariectomized rat as compared to normal rat, which was restored by perfusion with ANP. However, this observed cardioprotection was significantly attenuated by perfusion with L-NAME, an endothelial nitric oxide synthase inhibitor, and Glibenclamide, a KATP channel blocker, alone or in combination noted in terms of increase in myocardial infract size, release of CK-MB and LDH, and also decrease in release of NO. CONCLUSION: Thus, it is suggested that ANP restores the attenuated cardioprotective effect of IPC in the ovariectomized rat heart which may be due to increase in the availability of NO and consequent increase activation of mitochondrial KATP channels.

Reducing PTSD symptoms through a gender norms and economic empowerment intervention to reduce intimate partner violence: a randomized controlled pilot study in Côte D'Ivoire.

BACKGROUND: Women living in war-affected contexts face high levels of gender-based violence, including intimate partner violence (Stark & Ager, 2011). Despite well-documented negative consequences, including posttraumatic stress disorder (PTSD) (Garcia-Moreno et al. 2006; Steel et al. 2009), evidence remains thin regarding intervention effectiveness to mitigate consequences in these settings. METHODS: This study used a two-armed parallel pilot randomized controlled trial to compare the impact of a group savings only (control) to gender dialogue groups added to group savings (treatment) on women's symptoms of PTSD in northwestern Côte d'Ivoire. Eligible Ivorian women (18+ years, no prior experience with group savings) were invited to participate and 1198 were randomized into treatment groups. RESULTS: In the ITT analyses, women in the treatment arm had significantly fewer PTSD symptoms relative to the control arm (ß: -0.12; 95% CI: -0.20 to -0.03; p = 0.005). Partnered women in the treatment arm who had not experienced intimate partner violence (IPV) at baseline had significantly fewer PTSD symptoms than the control arm (ß = -0.12; 95% CI: -0.21 to -0.03; p = 0.008), while those who had experienced IPV did not show significant differences between treatment and control arms (ß = -0.09; 95% CI: -0.29 to 0.11; p = 0.40). CONCLUSIONS: Adding a couples gender discussion group to a women's savings group significantly reduced women's PTSD symptoms overall. Different patterns emerge for women who experienced IPV at baseline v. those who did not. More research is needed on interventions to improve mental health symptoms for women with and without IPV experiences in settings affected by conflict.

First Demonstration of a Scintillating Xenon Bubble Chamber for Detecting Dark Matter and Coherent Elastic Neutrino-Nucleus Scattering.

A 30-g xenon bubble chamber, operated at Northwestern University in June and November 2016, has for the first time observed simultaneous bubble nucleation and scintillation by nuclear recoils in a superheated liquid. This chamber is instrumented with a CCD camera for near-IR bubble imaging, a solar-blind photomultiplier tube to detect 175-nm xenon scintillation light, and a piezoelectric acoustic transducer to detect the ultrasonic emission from a growing bubble. The time of nucleation determined from the acoustic signal is used to correlate specific scintillation pulses with bubble-nucleating events. We report on data from this chamber for thermodynamic "Seitz" thresholds from 4.2 to 15.0 keV. The observed single- and multiple-bubble rates when exposed to a ^{252}Cf neutron source indicate that, for an 8.3-keV thermodynamic threshold, the minimum nuclear recoil energy required to nucleate a bubble is 19±6 keV (1σ uncertainty). This is consistent with the observed scintillation spectrum for bubble-nucleating events. We see no evidence for bubble nucleation by gamma rays at any of the thresholds studied, setting a 90% C.L. upper limit of 6.3×10^{-7} bubbles per gamma interaction at a 4.2-keV thermodynamic threshold. This indicates stronger gamma discrimination than in CF_{3}I bubble chambers, supporting the hypothesis that scintillation production suppresses bubble nucleation by electron recoils, while nuclear recoils nucleate bubbles as usual. These measurements establish the noble-liquid bubble chamber as a promising new technology for the detection of weakly interacting massive particle dark matter and coherent elastic neutrino-nucleus scattering.

Molecular markers for resistance against infectious diseases of economic importance.

Huge livestock population of India is under threat by a large number of endemic infectious (bacterial, viral, and parasitic) diseases. These diseases are associated with high rates of morbidity and mortality, particularly in exotic and crossbred cattle. Beside morbidity and mortality, economic losses by these diseases occur through reduced fertility, production losses, etc. Some of the major infectious diseases which have great economic impact on Indian dairy industries are tuberculosis (TB), Johne's disease (JD), mastitis, tick and tick-borne diseases (TTBDs), foot and mouth disease, etc. The development of effective strategies for the assessment and control of infectious diseases requires a better understanding of pathogen biology, host immune response, and diseases pathogenesis as well as the identification of the associated biomarkers. Indigenous cattle (Bos indicus) are reported to be comparatively less affected than exotic and crossbred cattle. However, genetic basis of resistance in indigenous cattle is not well documented. The association studies of few of the genes associated with various diseases, namely, solute carrier family 11 member 1, Toll-like receptors 1, with TB; Caspase associated recruitment domain 15, SP110 with JD; CACNA2D1, CD14 with mastitis and interferon gamma, BoLA--DRB3.2 alleles with TTBDs, etc., are presented. Breeding for genetic resistance is one of the promising ways to control the infectious diseases. High host resistance is the most important method for controlling such diseases, but till today no breed is total immune. Therefore, work may be undertaken under the hypothesis that the different susceptibility to these diseases are exhibited by indigenous and crossbred cattle is due to breed-specific differences in the dealing of infected cells with other immune cells, which ultimately influence the immune response responded against infections. Achieving maximum resistance to these diseases is the ultimate goal, is technically possible to achieve, and is permanent. Progress could be enhanced through introgression of resistance genes to breeds with low resistance. The quest for knowledge of the genetic basis for infectious diseases in indigenous livestock is strongly warranted.

Diagonal recurrent neural network based adaptive control of nonlinear dynamical systems using lyapunov stability criterion.

In this paper adaptive control of nonlinear dynamical systems using diagonal recurrent neural network (DRNN) is proposed. The structure of DRNN is a modification of fully connected recurrent neural network (FCRNN). Presence of self-recurrent neurons in the hidden layer of DRNN gives it an ability to capture the dynamic behaviour of the nonlinear plant under consideration (to be controlled). To ensure stability, update rules are developed using lyapunov stability criterion. These rules are then used for adjusting the various parameters of DRNN. The responses of plants obtained with DRNN are compared with those obtained when multi-layer feed forward neural network (MLFFNN) is used as a controller. Also, in example 4, FCRNN is also investigated and compared with DRNN and MLFFNN. Robustness of the proposed control scheme is also tested against parameter variations and disturbance signals. Four simulation examples including one-link robotic manipulator and inverted pendulum are considered on which the proposed controller is applied. The results so obtained show the superiority of DRNN over MLFFNN as a controller.