Modelling And Experimental Vibration Control Of A Two-link Three-dimensional Manipulator With Flexible Links

Current industrial and space manipulators are required to achieve higher speeds in a lighter structure without sacrificing payload capabilities. Consequently, undesirable vibration occurs during the motion. By suitable modelling of the manipulator flexibility, advanced control strategies can be formulated to improve the joint tracking performance and reduce the residual vibration of the end-point in the presence of payload uncertainties.;Toward this goal, an experimental two-link, 3D, anthropomorphic manipulator with flexible links was designed and built to be used as a test bed for the verification and refinement of the proposed modelling and control strategies.;The nonlinear equations of motion for the robot were derived using Lagrangian dynamics. The model was verified using experimental modal analysis techniques. Based on experimental results, a simplified nonlinear model, that contains the relevant modes of the system, was derived and subsequently used in controller designs and state estimation.;A conventional Proportional-plus-Derivative (PD) controller that implements joint angles feedback was designed to be used as a baseline controller due to its wide applicability on industrial manipulators.;By measuring the links tip vibration using accelerometers, several adaptive controllers and state observers were designed and implemented successfully on the manipulator, namely, a gain-scheduling linear quadratic regulator, a model reference adaptive controller, an adaptive inverse dynamics controller, a least-squares nonlinear state estimator and a robust sliding observer. The controllers performance and robustness were tested and experimentally verified against the change of the payload.;The control strategies and identification techniques, developed in this thesis, are applicable to a wide range of robot manipulators including industrial manipulators

Genetic engineering of

A commercial use of microbial produced products, like polyhydroxyalkanotes (PHAs), in the sense of an environmental precaution appears meaningful and necessary. In order to more economically produce microbial products, this investigation was focused on suitable producers, like the yeast Schizosaccharomyces pombe. Since it is not capable of the PHA synthesis, easily cultured and they must be modified genetically. Therefore, the genes of thePHB biosynthesis pathway of Ralstonia eutropha [beta-ketothiolase (phbARe); acetoacetyl-CoA reductase (phbBRe); as well as PHB synthase (phbCRe), located onto the plasmid pBHR68 were cloned into the cohesive ended pYIplac128 integrated vector that transformed into the chromosome of the yeast Schizosaccharomyces pombe strain Q01. Under the optimized cultivation conditions, the transgenic yeast S. pombe strain Q01/PHB was able to produce PHB and accumulated up to 9.018 % PHB. The presence of heterologous DNA in the transgenic yeast was examined by means of Western blot analysis. In addition, both PHA synthase activity and kinetics were determined. The UV/Vis, 1H and 13C NMR spectral analysis have confirmed that the polymer produced by the yeast S. pombe strain Q01/PHB is a pure homopolymer of 3-hydroxybutyric aci

PREPARATION AND EVALUATION OF CHEMICALLY INACTIVATED SALMONELLA ENTERITIDIS VACCINE IN CHICKENS

  Objective: Salmonella enteritidis ghosts (SEGs) is a non-living empty bacterial cell envelopes which were generated using a different concentration of sodium hydroxide (NaOH) 6.4 mg/mL and evaluated as a vaccine candidate in specific pathogen-free (SPF) chicken. SEGs have been produced by chemical-mediated lysis and evaluated the potential efficacy of chemically induced SEG vaccine and its ability to induce protective immune responses against virulent S. enteritidis challenge in SPF chickens.Methods: SPF chickens were divided into three groups: Group A (non-vaccinated control), Group B (vaccinated with prepared vaccine), and Group C (vaccinated with commercial vaccine).Results: Vaccination of SPF chicken with SEGs induced higher immune responses before and after virulent challenge. SPF chicken vaccinated with SEGs showed increasing in serum enzyme-linked immunosorbent assay (ELISA) antibodies. During the vaccination period, Groups B and C showed higher serum antibody titer compared to Group A. The minimal inhibitory concentration (MIC) of NaOH was capable of inducing non-living SEGs, and it has successfully generated non-living SEGs by MIC of NaOH.Conclusion: It is a one-step process which means easy manufacturing and low production cost compared to protein E-mediated lysis method. Chemically induced SEG vaccine is a highly effective method for inducing protective immunity. This study strongly suggests that SEGs will be a permissive vaccine, as the method of inhibition of S. enteritidis was safe and cheaper than other methods, and it gave a good protection

Biosynthesis of polyhydroxyalkanotes in wildtype yeasts

Biosynthesis of the biodegradable polymers polyhydroxyalkanotes (PHAs) are studied extensively in wild type and genetically modified prokaryotic cells, however the content and structure of PHA in wild type yeasts are not well documented. The purpose of this study was to screen forty yeast isolates collected from different Egyptian ecosystems for their ability to accumulate PHAs. Identification of the isolates and characterization of PHAs produced by the positive strains in the Nile-red staining assay was envisaged. One positive isolates which was identified using the API 20C yeast identification system as Rhodotorula minuta strain RY4 produced 2% of PHA in biomass, in glucose, oleic acid and tween 60 containing medium, over a growth period of 96 h. The nature of the PHA thus produced was analyzed by infrared spectroscopy and nuclear magnetic resonance (1H and 13C NMR) and found to contain polyhydroxybutyrate and  polyhydroxyvalerate. This study shows for the first time monomerdetection by 1H and/or 13C NMR of PHA polymers synthesized in wild type yeasts

Molecular epidemiology of antibiotic-associated diarrhoea due to Clostridium difficile and clostridium perfringens in Ain Shams University Hospitals

Background: As we are living in the era of antibiotic overuse, antibiotic associated diarrhea (AAD) is considered now a distinct health problem with a need for more attention. Aim of the Study: was to perform a highly specific detection and definition of pathogenic Clostridium perfringens and Clostridium difficile related AAD in children compared to adults and geriatircs. Patients and Methods: One hundred and fifty patients diagnosed for AAD were included in this study (50 children, 50 adults and 50 geriatric patients). All of them were subjected to full medical history including complete therapeutic history of antibiotics and collection of stool sample during the attack for detection of Clostridium perfringenes enterotoxin (CPEnt) and Clostridium difficile cytotoxin by (EIA) kit. PCR detection of Clostridium perfringenes cpe gene (Coding gene for CPEnt) was performed as well. Results: Results showed that prevalence of Clostridium difficile cytotoxin was 24% while Clostridium perfringenes enterotoxin was 12% as detected by EIA in faecal specimens as a whole. Detection of cpe gene by PCR was positive in 16% of all cases. Children (OR: 4.2, 95% CI: 1.3-14.8, P_0.01) and geriatric patients (OR: 3.4, 95% CI: 1.2-13.5, P_0.02) were significantly more prone to Clostridium difficile AAD compared to adults. Also, childhood was a significant risk for Clostridium perfringens AAD (OR: 2.1, 95% CI: 0.54-7.4, P_0.04). In Conclusion: children and geriatric patients are more vulnerable to develop AAD with antibiotic abuse compared to adults. Abbreviations: AAD=Antibiotic associated diarrhea, CI=Confidence interval, ELISA=Enzyme-linked immunosorbent assay, OR=Odd ratio, PCR=Polymerase chain reaction. Keywords: Antibiotic-associated diarrhea, children, Clostridium perfringens, Clostridium difficile. Egypt. J. Hum. Genet Vol. 8 (2) 2007: pp. 121-13

Significance of computerized tomography and nasal cytology in the diagnosis of rhinosinusitis among asthmatic children

Background: Chronic sinusitis, allergic rhinitis, and asthma are conditions that frequently coexist. Nasal sinus disease may contribute to poor control of asthma; this suggests that sinonasal involvement might be a risk factor for asthma severity and morbidity. Proposed mechanisms of this interaction include the presence of postnasal drip, nasobronchial reflex or systemic effect of mediators released from inflamed paranasal sinus tissue. Objective: In the present study, we sought to investigate the relationship of sinonasal inflammation as assessed by coronal sinus computerized tomography (CT) scanning, nasal cytology score, and asthma severity. Methods: Twenty-five children with asthma were recruited from the Pediatric Respiratory Clinic of Ain Shams University. Their ages ranged from 5-13 years with a mean age of 7.78 years. Twenty healthy children who were age- and sex-matched and who had normal sinus CT scans were selected as the control group. Patients were subjected to asthma severity assessment, nasal cytology, total serum IgE assay, and paranasal CT scanning and scoring. Results: Sinus CT scoring showed abnormalities in 88% of asthmatic children, and sinus CT scores correlated positively to asthma severity. Nasal cytology scores for eosinophils and neutrophils correlated positively with sinus CT scores. The most frequent symptoms associated with sinusitis were rhinorrhea (68%) and nasal obstruction (40%). The maxillary sinus was the most frequently affected one followed by the ethmoid sinus. Pathological features included mucosal thickening, osteomeatal complex occlusion, and polyp formation. Conclusion: Computed tomography scan is a useful diagnostic tool for assessment of sinus disease in asthmatic children. Rhinosinusitis is a common asthma comorbidity. Nasal eosinophil or neutrophil score >0.5 provides a better predictive value for rhinosinusitis compared to total serum IgE.Keywords: computerized tomography, nasal sinus, asthma, sinusitis, allergic rhinitis, childrenEgypt J Pediatr Allergy Immunol 2003; 1(2):94-10

Sparsest factor analysis for clustering variables: a matrix decomposition approach

We propose a new procedure for sparse factor analysis (FA) such that each variable loads only one common factor. Thus, the loading matrix has a single nonzero element in each row and zeros elsewhere. Such a loading matrix is the sparsest possible for certain number of variables and common factors. For this reason, the proposed method is named sparsest FA (SSFA). It may also be called FA-based variable clustering, since the variables loading the same common factor can be classified into a cluster. In SSFA, all model parts of FA (common factors, their correlations, loadings, unique factors, and unique variances) are treated as fixed unknown parameter matrices and their least squares function is minimized through specific data matrix decomposition. A useful feature of the algorithm is that the matrix of common factor scores is re-parameterized using QR decomposition in order to efficiently estimate factor correlations. A simulation study shows that the proposed procedure can exactly identify the true sparsest models. Real data examples demonstrate the usefulness of the variable clustering performed by SSFA

Clinical Symptoms of Arboviruses in Mexico

Arboviruses such as Chikungunya (CHIKV), Dengue (DENV), and Zika virus (ZIKV) have emerged as a significant public health concern in Mexico. The existing literature lacks evidence regarding the dispersion of arboviruses, thereby limiting public health policy’s ability to integrate the diagnosis, management, and prevention. This study seeks to reveal the clinical symptoms of CHIK, DENV, and ZIKV by age group, region, sex, and time across Mexico. The confirmed cases of CHIKV, DENV, and ZIKV were compiled from January 2012 to March 2020. Demographic characteristics analyzed significant clinical symptoms of confirmed cases. Multinomial logistic regression was used to assess the association between clinical symptoms and geographical regions. Females and individuals aged 15 and older had higher rates of reported significant symptoms across all three arboviruses. DENV showed a temporal variation of symptoms by regions 3 and 5, whereas ZIKV presented temporal variables in regions 2 and 4. This study revealed unique and overlapping symptoms between CHIKV, DENV, and ZIKV. However, the differentiation of CHIKV, DENV, and ZIKV is difficult, and diagnostic facilities are not available in rural areas. There is a need for adequately trained healthcare staff alongside well-equipped lab facilities, including hematological tests and imaging facilities

Vaccination with DNA plasmids expressing Gn coupled to C3d or alphavirus replicons expressing Gn protects mice against rift valley fever virus

Background: Rift Valley fever (RVF) is an arthropod-borne viral zoonosis. Rift Valley fever virus (RVFV) is an important biological threat with the potential to spread to new susceptible areas. In addition, it is a potential biowarfare agent. Methodology/Principal Findings: We developed two potential vaccines, DNA plasmids and alphavirus replicons, expressing the Gn glycoprotein of RVFV alone or fused to three copies of complement protein, C3d. Each vaccine was administered to mice in an all DNA, all replicon, or a DNA prime/replicon boost strategy and both the humoral and cellular responses were assessed. DNA plasmids expressing Gn-C3d and alphavirus replicons expressing Gn elicited high titer neutralizing antibodies that were similar to titers elicited by the live-attenuated MP12 virus. Mice vaccinated with an inactivated form of MP12 did elicit high titer antibodies, but these antibodies were unable to neutralize RVFV infection. However, only vaccine strategies incorporating alphavirus replicons elicited cellular responses to Gn. Both vaccines strategies completely prevented weight loss and morbidity and protected against lethal RVFV challenge. Passive transfer of antisera from vaccinated mice into naïve mice showed that both DNA plasmids expressing Gn-C3d and alphavirus replicons expressing Gn elicited antibodies that protected mice as well as sera from mice immunized with MP12. Conclusion/Significance: These results show that both DNA plasmids expressing Gn-C3d and alphavirus replicons expressing Gn administered alone or in a DNA prime/replicon boost strategy are effective RVFV vaccines. These vaccine strategies provide safer alternatives to using live-attenuated RVFV vaccines for human use. © 2010 Bhardwaj et al

Melanoma cells break down LPA to establish local gradients that drive chemotactic dispersal.

The high mortality of melanoma is caused by rapid spread of cancer cells, which occurs unusually early in tumour evolution. Unlike most solid tumours, thickness rather than cytological markers or differentiation is the best guide to metastatic potential. Multiple stimuli that drive melanoma cell migration have been described, but it is not clear which are responsible for invasion, nor if chemotactic gradients exist in real tumours. In a chamber-based assay for melanoma dispersal, we find that cells migrate efficiently away from one another, even in initially homogeneous medium. This dispersal is driven by positive chemotaxis rather than chemorepulsion or contact inhibition. The principal chemoattractant, unexpectedly active across all tumour stages, is the lipid agonist lysophosphatidic acid (LPA) acting through the LPA receptor LPAR1. LPA induces chemotaxis of remarkable accuracy, and is both necessary and sufficient for chemotaxis and invasion in 2-D and 3-D assays. Growth factors, often described as tumour attractants, cause negligible chemotaxis themselves, but potentiate chemotaxis to LPA. Cells rapidly break down LPA present at substantial levels in culture medium and normal skin to generate outward-facing gradients. We measure LPA gradients across the margins of melanomas in vivo, confirming the physiological importance of our results. We conclude that LPA chemotaxis provides a strong drive for melanoma cells to invade outwards. Cells create their own gradients by acting as a sink, breaking down locally present LPA, and thus forming a gradient that is low in the tumour and high in the surrounding areas. The key step is not acquisition of sensitivity to the chemoattractant, but rather the tumour growing to break down enough LPA to form a gradient. Thus the stimulus that drives cell dispersal is not the presence of LPA itself, but the self-generated, outward-directed gradient