Sensors for Rate Responsive Pacing

Advances in pacemaker technology in the 1980s have generated a wide variety of complex multiprogrammable pacemakers and pacing modes. The aim of the present review is to address the different rate responsive pacing modalities presently available in respect to physiological situations and pathological conditions. Rate adaptive pacing has been shown to improve exercise capacity in patients with chronotropic incompetence. A number of activity and metabolic sensors have been proposed and used for rate control. However, all sensors used to optimize pacing rate metabolic demands show typical limitations. To overcome these weaknesses the use of two sensors has been proposed. Indeed an unspecific but fast reacting sensor is combined with a more specific but slower metabolic one. Clinical studies have demonstrated that this methodology is suitable to reproduce normal sinus behavior during different types and loads of exercise. Sensor combinations require adequate sensor blending and cross checking possibly controlled by automatic algorithms for sensors optimization and simplicity of programming. Assessment and possibly deactivation of some automatic functions should be also possible to maximize benefits from the dual sensor system in particular conditions. This is of special relevance in patient whose myocardial contractility is limited such as in subjects with implantable defibrillators and biventricular pacemakers. The concept of closed loop pacing, implementing a negative feedback relating pacing rate and the control signal, will provide new opportunities to optimize dual-sensors system and deserves further investigation. The integration of rate adaptive pacing into defibrillators is the natural consequence of technical evolution

Considerations on bio-hydrogen production from organic waste in South African municipalities: A review

Organic waste disposal contributes to 3.8% of GHG emissions to the atmosphere, yet 68.8% of this putrescible waste fraction is still disposed of, untreated, to landfills in South Africa. The implementation of a ban on disposal of organic waste to landfills at provincial level opens up the need to research best technology pathways and waste minimisation strategies to valorise and promote the circularity of diverted waste streams. The SARChI Chair in Waste and Climate Change has developed the WROSE™ (Waste Resource Optimization Scenario Evaluation) model to assist municipalities in selecting the most appropriate waste management solutions. A research gap has been identified in the lack of information on full-scale applications of two-stage anaerobic digestion (2-stage AD) for combined bio-hydrogen and bio-methane production from organic waste. In this review, we explore drivers and barriers to the implementation of 2-stage AD in South Africa and propose possible scenarios using the WROSE™ model for its insertion into an Integrated Waste Management System at municipal level. A literature analysis suggests that 2-stage AD is a potentially viable solution to recover the inherent value of organic waste and promote circularity using bio-hydrogen and bio-methane. However, the currently available organic fraction in the municipal solid waste streams is not a suitable feedstock, as it requires high levels of pre-treatment. Suitable scenarios using the WROSE™ model are proposed for South African municipalities, paving the way for future research towards the scale-up of this technology.Significance:• Organic waste is not managed adequately in South Africa, contributing to greenhouse gas emissions without recovering the intrinsic value of the material.• 2-stage AD is a potentially viable solution to recover the inherent value of organic waste and promote circularity using bio-hydrogen and bio-methane. Several barriers must be overcome before carrying out the technology at full-scale.• A 2-stage AD scenario can be implemented at full-scale into an Integrated Waste Management System using appropriate decision-making tools such as WROSE™

Pacemaker Prevention Therapy in Drug–refractory Paroxysmal Atrial Fibrillation: Reliability of Diagnostics and Effectiveness of Prevention Pacing Therapy in Vitatron™ Selection® device

Introduction. Atrial fibrillation (AF), the most common and rising disorder of cardiac rhythm, is quite difficult to control and/or to treat. Non pharmacological therapies for AF may involve the use of dedicated pacing algorithms to detect and prevent atrial arrhythmia that could be a trigger for AF onset. Selection 900E/AF2.0 Vitatron DDDRP pacemaker (1) keeps an atrial arrhythmia diary thus providing detailed onset reports of arrhythmias of interest, (2) provides us data about the number of premature atrial contractions (PACs) and (3) plots heart rate in the 5 minutes preceding the detection of an atrial arrhythmia. Moreover, this device applies four dedicated pacing therapies to reduce the incidence of atrial arrhythmia and AF events. Aim of the Study. To analyze the reliability to record atrial arrhythmias and evaluate effectiveness of its AF preventive pacing therapies. Material and Methods. We enrolled 15 patients (9 males and 6 females, mean age of 71±5 years, NYHA class I–II), with a DDDRP pacemaker implanted for a “bradycardia–tachycardia” syndrome, with advanced atrioventricular conduction disturbances. We compared the number and duration of AF episodes’ stored in the device with a contemporaneous 24h Holter monitoring. After that, we switched on the atrial arrhythmias detecting algorithms, starting from an atrial rate over 180 beats per minute for at least 6 ventricular cycles, and ending with at least 10 ventricular cycles in sinus rhythm. Thereafter, in order to evaluate the possible reduction in PACs number and in number and duration of AF episodes, we tailored all the four pacing preventive algorithms. Patients were followed for 24±8 months (from 20 to 32 months). Results. All 59 atrial arrhythmia episodes occurred in the first part of this trial, were correctly recorded by both systems, with a correlation coefficient (r) of 0.96. During the follow–up, we observed a significant reduction not only in PACs number (from 83±12/day to 2.3±0.8/day) but also in AF episodes (from 46±7/day to 0.12±0.03/day) and AF burden (from 93%±6% to 0.3%±0.06%). An increase in atrial pacing percentages (from 3%±0.5% to 97%±3%) was also contemporaneously observed. Conclusion. In this pacemaker, detection of atrial arrhythmia episodes is highly reliable, thus making available an appropriate monitoring of heart rhythm, mainly suitable in AF asymptomatic patients. Moreover, the significant reduction of atrial arrhythmia episodes indicates that this might represent a suitable therapeutic option for an effective preventive therapy of AF in paced brady–tachy patients

Rapid Methods as Analytical Tools for Food and Feed Contaminant Evaluation: Methodological Implications for Mycotoxin Analysis in Cereals

Over the past years, food quality is perceived to have improved and food safety has become an important food quality attribute (R\uf6hr et al., 2005). This implies that all aspects of food production and therefore of the feed supply chain must be considered to ensure the safety of human food (Pinotti & Dell\u2019Orto, 2011). As a result, public authorities and regulatory agencies are pushing producers, manufacturers, and researchers to pay serious attention to food and feed production processes and to develop comprehensive quality policies and management systems to improve food safety and try to enhance consumer information to regain consumers trust in food. From this point of view, the knowledge and control of the level and distribution of contaminants and undesirable substances in food and feed are become a worldwide topic of interest due to the high economic and sanitary impact on human/animal health. Since it is impossible to fully eliminate the presence of undesirable substances and contaminants, an adequate surveillance and frequent checks are fundamental to assure quality and safety of raw materials destined for direct consumption or industrial processes. The aim of this chapter will be to evaluate the potentiality offered by rapid analytical approaches to food and feed evaluation, focusing on contaminants and undesirable substances. A critical overview, highlighting characteristics and applications of these techniques, will be offered with examples pointed on specific matrices and contaminants,cereals and mycotoxins, respectively

Mycotoxins in Wheat and Mitigation Measures

Latest estimates for world cereal production in 2015 and EU‐28 production in 2014 are approximately 2540 and 323 mil tons, respectively. The FAO estimated that the global wheat consumption is about 66 kg/per capita. Among the most important risks associated with wheat consumption are mycotoxins. It has been estimated that up to 25% of the world\u27s crops grown for food and feed may be contaminated with mycotoxins. Despite efforts in controlling fungal growth, mycotoxin co‐contamination represents an unavoidable risk, occurring pre‐ and postharvest and resulting in reduced nutritional value and possible risks for human and animal health. In addition to health risks, mycotoxins have a detrimental effect on the quality and the processing performance of wheat. Mitigation measures to manage the challenge of mycotoxins in wheat include strategies at pre‐ and postharvest. Preharvest events are predominantly dictated by environmental factors and good agronomic/cultural practices, whereas storage and processing are the major areas where contamination can be prevented at postharvest. Integrating as many management options as possible may minimize the risk of mycotoxin contamination in wheat and wheat products

La prevalencia y difusión de la tuberculosis en el Chaco y la ciudad de Resistencia

El presente aporte intenta mostrar una aproximación a la situación de la Tuberculosis en la Provincia y en el Área Metropolitana del Gran Resistencia, a partir de datos proporcionados por la Dirección de Estadísticas Sanitarias de la Provincia del Chaco para los años 2000 y 2007. Un pequeño recorrido por la situación a nivel mundial, de los distintos continentes y de la República Argentina nos permite visualizar las diferencias con el contexto provincial y nuestra semejanza con países asiáticos. La Tuberculosis es una enfermedad que encuentra un ambiente propicio para su desarrollo en poblaciones con falta de agua potable, insalubridad de la vivienda y, en especial, con hacinamiento, factores que siguen actuando como agentes propicios para el desarrollo de esta enfermedad.

Effect of iron deficiency on the localization of phosphoenolpyruvate carboxylase in common bean nodules

Phosphoenolpyruvate carboxylase (PEPC) plays an important role in nodules, when there is an increase in the demand for energy. This enzyme provides carbon skeletons to sustain amino acid synthesis and malate to support energy required to fix nitrogen. Since PEPC is important for nodules, and there is lack of information about the effect of some nutrient deficiency in the expression and localization of this enzyme in legume nodules, this work focused on the localization of PEPC in nodules under iron deficiency of two common bean cultivars: Flamingo tolerant and Coco blanc sensitive to iron (Fe) deficiency. The results of immunolocalization using polyclonal antibody showed that this enzyme was detected in all regions of nodule sections; but the signal intensity was increased in Fe-deficient nodules as compared to Fe-sufficient ones in the tolerant cultivar, whereas the intensity was less pronounced in nodules of Fe-deficient plants than in those of Fe-sufficient plants for the sensitive cultivar Coco blanc. This work showed that the symbiotic tolerance of Flamingo to iron deficiency was linked to the increase of PEPC enzymes expression. However, the activity of these enzymes supported the energy required in bacteroids to maintain the nitrogenase activity.Keywords: Common bean, immunolocalization, iron deficiency, nodules, phosphoenol pyruvate carboxylas