Contactless Rotor Ground Fault Detection Method for Brushless Synchronous Machines Based on an AC/DC Rotating Current Sensor.

Brushless synchronous machines (BSMs) are replacing conventional synchronous machines with static excitation in generation facilities due to the absence of sparking and lower maintenance. However, this excitation system makes measuring electric parameters in the rotor challenging. It is highly difficult to detect ground faults, which are the most common type of electrical fault in electric machines. In this paper, a ground fault detection method for BSMs is proposed. It is based on an inductive AC/DC rotating current sensor installed in the shaft. In the case of a ground fault in the rotating parts of the BSM, a fault current will flow through the rotor's sensor, inducing voltage in its stator. By analyzing the frequency components of the induced voltage, the detection of a ground fault in the rotating elements is possible. The ground faults detection method proposed covers the whole rotor and discerns between DC and AC sides. This method does not need any additional power source, slip ring, or brush, which is an important advantage in comparison with the existing methods. To corroborate the detection method, experimental tests have been performed using a prototype of this sensor connected to laboratory synchronous machines, achieving satisfactory results.

Cost-Effectiveness of the Comprehensive Interdisciplinary Program-Care in Informal Caregivers of People with Alzheimer's Disease.

People with Alzheimer's disease (AD) diagnosis who get informal care remain at home longer, reducing the demand for healthcare resources but increasing the stress of caregiving. Research on the effectiveness of physical training, psychoeducational, cognitive-behavioural, and health education programs in reducing the caregiver load and enhancing health-related quality of life (HRQoL) exist, but none exist about an integrated interdisciplinary program. The goals of this project are (1) to assess the Integral-CARE Interdisciplinary Program (IP) applicability, safety, effects on HRQoL, and the incremental cost-effectiveness ratio for AD caregivers; (2) to evaluate the IP applicability and cost-effectiveness to enhance the physical, psychoemotional, cognitive-behavioural dimensions, and the health education status of informal caregivers, and (3) to study the transference of the results to the public and private sectors. A randomized controlled trial will be conducted with an experimental (IP) and a control group (no intervention). The PI will be conducted over nine months using face-to-face sessions (twice a week) and virtual sessions on an online platform (once a week). There will be an initial, interim (every three months), and final assessment. Focus groups with social and health agents will be organized to determine the most important information to convey to the public and private sectors in Extremadura (Spain). Applicability, safety, HRQoL, incremental cost-effectiveness ratio, and HRQoL will be the main outcome measures, while secondary measures will include sociodemographic data; physical, psychoemotional, health education, and cognitive-behavioural domains; program adherence; and patient health status. Data will be examined per procedure and intention to treat. A cost-effectiveness study will also be performed from the viewpoints of private and public healthcare resources.

Síndrome de Wellens: o infarto agudo do miocárdio iminente / Wellens Syndrome: impending acute myocardial infarction

A síndrome de Wellens foi descrita em 1982 por Zwaan, Bär e Wellens. No eletrocardiograma, observam-se alterações morfológicas da onda T nas derivações precordiais, sugerindo estenose proximal grave da artéria coronária descendente anterior que representa iminente risco de infarto agudo do miocárdio e/ou morte súbita, com discreta ou nenhuma alteração da troponina sérica. Seu reconhecimento antecipado e a abordagem com reperfusão miocárdica precoce evitam desfechos desfavoráveis. A intervenção coronária percutânea e a revascularização miocárdica cirúrgica são as estratégias mais utilizadas para tratamento. Os autores descrevem dois casos de síndrome de Wellens tipos A e B tratados por diferentes estratégias de reperfusão.

Wellens syndrome was described by Zwaan, Bär and Wellens, in 1982. On the electrocardiogram, T wave morphological alterations are observed in precordial leads, suggesting severe proximal stenosis of the left anterior descending coronary artery and an imminent risk of acute myocardial infarction and/or sudden death, with slight or no alteration in serum troponin. Its early recognition and management with early myocardial reperfusion avoid unfavorable outcomes. Percutaneous coronary intervention and surgical myocardial revascularization are the most used strategies for treatment. The authors describe two cases of types A and B Wellens syndrome treated with different reperfusion strategies.

Enfermedad arterial coronaria y sus características clínico-angiográficas: Realidad de un centro de atención terciaria privado en Angola / Coronary artery disease and its clinical-angiographic characteristics: Reality of a private tertiary care center in Angola

RESUMEN Introducción: La enfermedad arterial coronaria ha experimentado un aumento entre los angolanos debido a la transición epidemiológica resultante de los nuevos estilos de vidas desfavorables para la salud cardiovascular. Objetivo: Realizar una caracterización clínico-angiográfica de los pacientes con sospecha de enfermedad arterial coronaria llevados a coronariografía. Método: Estudio observacional retrospectivo, realizado en la Clínica Girassol, con 450 pacientes llevados a coronariografía durante enero del 2012 a diciembre del 2018. Se incluyeron variables clínicas (sexo, edad, tipo de procedimiento, factores de riesgo, indicación clínica) y angiográficas (vía de acceso, vasos afectados, dominancia coronaria, estrategia de tratamiento y complicaciones). Resultados: Predominó el sexo masculino (71,6%) con edad media de 59,7(11,2 años. La hipertensión arterial fue el factor de riesgo predominante (76,0%). El 56,2% de los procedimientos fueron realizados de urgencia siendo el síndrome coronario agudo con elevación del ST (37,3%) el más frecuente. La mayoría de los procedimientos (81,1%) fueron por vía femoral. La descendente anterior estuvo afectada en el 37,6% de los casos y la dominancia derecha fue la más prevalente (94,0%). El hematoma femoral constituyó la complicación más frecuente (0,9%). Conclusiones: En los pacientes intervenidos predominó el sexo masculino, las edades avanzadas, la hipertensión arterial y la realización urgente del procedimiento, mayoritariamente por síndromes coronarios agudos con elevación del segmento ST, con muy baja incidencia de complicaciones.

ABSTRACT Introduction: Coronary artery disease has progressively increased among Angolans due to the epidemiological transition resulting from new lifestyles unfavorable to cardiovascular health. Objective: To perform a clinical-angiographic characterization of patients suspected of coronary artery disease undergoing coronary angiography. Method: Retrospective observational study, conducted at Clínica Girassol, with 450 patients who underwent coronary angiography from January 2012 to December 2018. Clinical variables such as sex, age, type of procedure, risk factors, clinical indication, and angiographic features (access route, vessels involved, coronary dominance, treatment strategy and complications) were included. Results: Male sex predominated (71.6%) with a mean age of 59.7±11.2 years. Hypertension was the predominant risk factor (76.0%). Emergency procedures accounted for 56.2% of the interventions; ST-segment elevation acute coronary syndrome (37.3%) was the most frequent. Most of the procedures (81.1%) were performed via the femoral artery. The left anterior descending artery was involved in 37.6% of the cases and right dominance was the most prevalent (94.0%). Femoral hematoma was the most frequent complication (0.9%). Conclusions: The patients who underwent surgery were predominantly male, older, hypertensive, and required urgent procedures, mostly for ST-segment elevation acute coronary syndromes, with very low rates of complications.

Product Design by Additive Manufacturing for Water Environments: Study of Degradation and Absorption Behavior of PLA and PETG.

Additive manufacturing technologies are shifting from rapid prototyping technologies to end use or final parts production. Polymeric material extrusion processes have been broadly addressed with a specific definition of all parameters and variables for all different of technologies approaches and materials. Recycled polymeric materials have been studied due to the growing importance of the environmental awareness of the contemporary society. Beside this, little specific research has been found in product development applications for AM where the printed parts are in highly moisture environments or surrounded by water, but polymers have been for long used in such industries with conventional manufacturing approaches. This work focuses on the analysis and comparison of two different additively manufactured polymers printed by fused filament fabrication (FFF) processes using desktop-size printers to be applied for product design. The polymers used have been a recycled material: polyethylene terephthalate glycol (PETG) and polylactic acid (PLA). Degradation and water absorption behaviors of both materials are presented, analyzed and discussed in this paper, where different samples have been immersed in saturated solutions of water with maritime salt and sugar together with a control sample immersed in distilled water. The samples have been dimensionally and weight-controlled weekly as well as microscopically analyzed to understand degradation and absorption processes that appear in the fully saturated solutions. The results revealed how the absorption process is stabilized after a reduced number of weeks for both materials and how the degradation process is more remarked in the PLA material due to its organic nature.

Cardiorespiratory Fitness in Spanish Firefighters: Age Differences and Associations Between Fitness-Related Parameters.

OBJECTIVE: To evaluate the cardiorespiratory fitness and other fitness-related measures, and to analyze the differences among age groups. METHODS: This study was conducted on 104 firefighters. Maximal oxygen uptake (VO2 max) was assessed using the Shuttle Test and fitness was evaluated using appropriate physical tests. RESULTS: Mean VO2 max was 45.7 mL/kg/min and 60.6% of firefighters were over the minimum accepted standpoint to do effective work, however, the VO2 max decreased with increasing age. 35.6% of the firefighters were overweight. Age, weight, and total body fat were found to be significant predictors of VO2 max level in this population, with total body fat as strongest predictor. CONCLUSIONS: Healthy habits-based interventions tailored by age groups should be promoted, to improve cardiorespiratory fitness and body composition for safe work and to improve firefighters' health.

Fast and Clean Synthesis of Nylon-6/Synthetic Saponite Nanocomposites.

Nylon/saponite nanocomposites were synthesized and characterized. The nanocomposites were prepared by means of a fast, efficient, low cost, and environmentally friendly method. All of the tested preparations resulted in the pre-designed nanocomposites. To this end, delaminated saponites were directly synthesized to be used as a filler in a polymer matrix formed by nylon-6 by the in situ intercalation polymerisation of an ε-caprolactam monomer without the use of surfactants or other organic reagents to organophilise the clay, thus avoiding the drawbacks of contamination. The efficiency of the preparation method increased, and significant savings were achieved in terms of both energy reaction time, savings of 60% and 70%, respectively, by using microwave radiation as an energy source during the synthesis of the nanocomposites. In addition, given that the method that was followed avoids the use of contaminating organophilic agents, it is important to highlight the savings in reagents and the fact that there was zero environmental contamination.

AC/DC Current Sensor for Rotating Applications.

There are several techniques for current measurement. Most of them are capable of measuring both alternating and direct current (AC/DC) components. However, they have severe drawbacks for rotating applications (large size, sensitivity to external fields, and low signal amplitude). In addition to these weaknesses, measured signals should be transmitted to a stationary part. In order to contribute solving these difficulties, this paper presents a sensor that can measure AC/DC simultaneously based on the electromagnetic coupling of two coils. To this aim, the measured waveform is analysed. In this paper, the design of such a sensor is presented. This design is validated through computer simulations and a prototype is built. The performance of this sensor prototype is analysed through experimental tests.

Cor triatriatum sinister, una anomalía clásica pero un tanto olvidada: A propósito de un caso / Cor triatriatum sinister, a classic but somewhat forgotten anomaly: Apropos of a case

RESUMEN Un corazón con tres aurículas, que sumaba cinco cámaras en total, fue un hecho que sorprendió a la medicina hace ya más de un siglo. Este raro defecto cardíaco congénito tiene muy baja incidencia, lo cual hace que sea muy poco conocido por las jóvenes generaciones de médicos dedicados a las enfermedades cardiovasculares. El cor triatriatum sinister generalmente se diagnostica en la temprana infancia y es considerado una causa congénita de estenosis mitral. La conducta quirúrgica es de elección para poder liberar el obstáculo al adecuado flujo sanguíneo a través de la aurícula izquierda. Se presenta el caso de un adulto joven con síntomas típicos de estenosis mitral, sin aparentes elementos claves al examen físico y con un ecocardiograma que evidencia esta anomalía, apenas vista y publicada en nuestro medio en pacientes adultos.

ABSTRACT A heart with three atria, totaling five chambers in all, was a fact that surprised medicine more than a century ago. This rare congenital heart defect has a very low incidence, which makes it very little known to the young generations of doctors dedicated to cardiovascular diseases. The cor triatriatum sinister is usually diagnosed in early childhood, and it is considered a congenital cause of mitral stenosis. Surgical approach is the choice to release the obstacle in order to adequate blood flow through the left atrium. We present the case of a young adult with typical symptoms of mitral stenosis, without apparent key elements on the physical examination and that the echocardiogram showed this anomaly, hardly seen and published in our field in adult patients.

CLIN-IK-LINKS: A platform for the design and execution of clinical data transformation and reasoning workflows.

BACKGROUND AND OBJECTIVE: Effective sharing and reuse of Electronic Health Records (EHR) requires technological solutions which deal with different representations and different models of data. This includes information models, domain models and, ideally, inference models, which enable clinical decision support based on a knowledge base and facts. Our goal is to develop a framework to support EHR interoperability based on transformation and reasoning services intended for clinical data and knowledge. METHODS: Our framework is based on workflows whose primary components are reusable mappings. Key features are an integrated representation, storage, and exploitation of different types of mappings for clinical data transformation purposes, as well as the support for the discovery of new workflows. The current framework supports mappings which take advantage of the best features of EHR standards and ontologies. Our proposal is based on our previous results and experience working with both technological infrastructures. RESULTS: We have implemented CLIN-IK-LINKS, a web-based platform that enables users to create, modify and delete mappings as well as to define and execute workflows. The platform has been applied in two use cases: semantic publishing of clinical laboratory test results; and implementation of two colorectal cancer screening protocols. Real data have been used in both use cases. CONCLUSIONS: The CLIN-IK-LINKS platform allows the composition and execution of clinical data transformation workflows to convert EHR data into EHR and/or semantic web standards. Having proved its usefulness to implement clinical data transformation applications of interest, CLIN-IK-LINKS can be regarded as a valuable contribution to improve the semantic interoperability of EHR systems.

Preparation of Al/Fe-PILC clay catalysts from concentrated precursors: enhanced hydrolysis of pillaring metals and intercalation.

The modification of bentonite with Al-Fe species from different concentrated precursors at both stages: (i) the preparation of the (Al/Fe)-mixed pillaring solution and (ii) intercalation itself, was studied at lab scale. The final solids were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), Cationic Exchange Capacity (CEC), textural analyses by nitrogen adsorption-desorption at 77 K, and hydrogen-temperature programmed reduction (H2-TPR). Finally, the modified clays were assessed as active materials in the Catalytic Wet Peroxide Oxidation (CWPO) of phenol under very mild conditions through 1.0 h of reaction: T = 25.0 °C ± 0.1 °C, pH = 3.7, ambient pressure (76 kPa), and 0.5 g catalyst per dm3. Metal hydrolysis by the dissolution of elemental aluminium (final Total Metal Concentration TMC = 4.62 mol dm-3) achieved the best results, decreasing the volume of solution per mass unit of clay required to successfully expand the layered starting mineral by a factor of close to 75, in comparison with the widespread conventional preparation using highly diluted Al-based pillaring solutions. Even in the absence of any solvent for the clay dispersion, the intercalating/pillaring method was shown to be favourable, as a novel strategy promoting the process intensification and subsequent preparation of Al/Fe- and other Al-based pillared clays at larger scales. The best catalyst prepared from concentrated precursors exhibited 79.1% phenol conversion, 19.3% TOC mineralization, and pretty low iron leaching (0.037 mg Fe dm-3; ∼0.12% w/w) in such a short catalytic assessment; all these results were quite comparable or even exceeded those exhibited by the catalyst prepared from dilute precursors.

White and Red Brazilian São Simão's Kaolinite-TiO2 Nanocomposites as Catalysts for Toluene Photodegradation from Aqueous Solutions.

The presence of volatile organic compounds in groundwater is a major concern when it is used as a drinking water source because many of these compounds can adversely affect human health. This work reports on the preparation and characterization of white and red Brazilian São Simão's kaolinite-TiO2 nanocomposites and their use as catalysts in the photochemical degradation of toluene, a significant volatile organic compound. The nanocomposites were prepared by a sol-gel procedure, using titanium bis(triethanolaminate)diisopropoxide as a precursor. Thermal treatments of the nanocomposites led to different polymorphic titania phases, while the clay changed from kaolinite to metakaolinite. This structural evolution strongly affected the photocatalytic degradation behavior-all the solids efficiently degraded toluene and the solid calcined at 400 °C, formed by kaolinite and anatase, showed the best behavior (90% degradation). On extending the photochemical treatment up to 48 h, high mineralization levels were reached. The advantage of photodegradation using the nanocomposites was confirmed by comparing the results from isolated components (titanium dioxide and kaolinite) to observe that the nanocomposites displayed fundamental importance to the photodegradation pathways of toluene.

Effect of High Pressure on the Reducibility and Dispersion of the Active Phase of Fischer-Tropsch Catalysts.

The effect of high pressure on the reducibility and dispersion of oxides of Co and Fe supported on γ-Al2O3, SiO2, and TiO2 has been studied. The catalysts, having a nominal metal content of 10 wt.%, were prepared by incipient wetness impregnation of previously calcined supports. After drying at 60 °C for 6 h and calcination at 500 °C for 4 h, the catalysts were reduced by hydrogen at two pressures, 1 and 25 bar. The metal reduction was studied by temperature-programmed reduction up to 750 °C at the two pressures, and the metal dispersion was measured by CO chemisorption at 25 °C, obtaining values between 1% and 8%. The physicochemical characterization of these materials was completed by means of chemical analysis, X-ray diffraction, N2 adsorption-desorption at -196 °C and scanning electron microscopy. The high pressure lowered the reduction temperature of the metal oxides, improving their reducibility and dispersion. The metal reducibility increased from 42%, in the case of Fe/Al2O3 (1 bar), to 100%, in the case of Fe/TiO2 (25 bar).

Variation of the Pore Morphology during the Early Age in Plain and Fiber-Reinforced High-Performance Concrete under Moisture-Saturated Curing.

In this paper, two concrete mixtures of plain concrete (PC) and steel fiber-reinforced high-performance concrete (SFRC) have been scanned in order to analyze the variation of the pore morphology during the first curing week. Six cylinders of 45.2-mm diameter 50-mm height were performed. All of the specimens were kept in a curing room at 20 °C and 100% humidity. A computed tomography (CT) scan was used to observe the internal voids of the mixtures, and the data were analyzed using digital image processing (DIP) software, which identified and isolated each individual void in addition to extracting all of their geometrical parameters. The results revealed that the SFRC specimens showed a greater porosity than the PC ones. Moreover, the porosity increased over time in the case of SFRC, while it remained almost constant in the case of PC. The porosity increased with the depth in all cases, and the lowest porosity was observed in the upper layer of the specimens, which is the one that was in contact with the air. The analysis of the results showed that the fibers provided additional stiffness to the cement paste, which was especially noticeable during this first curing week, resulting in an increasing of the volume of the voids and the pore size, as well as a reduction in the shape factor of the voids, among other effects.

Publisher Correction: Z-ring membrane anchors associate with cell wall synthases to initiate bacterial cell division.

The original version of this Article contained errors in Figures 1 and 3. In Fig. 1b, the label 'IP-PBP3' above the second of the three blots incorrectly read 'IP-PBP1B'. In Fig. 3b, the label 'PBP1B' under the first bar of each chart incorrectly read 'PBP1A'. These errors have been corrected in both the PDF and HTML versions of the Article.

Recent advances in the use of computed tomography in concrete technology and other engineering fields.

Over the past two decades, immense research efforts at a global level have extended CT-Scan technology across several engineering fields. The state-of-the-art of the most relevant research related to the use of CT-Scanning is presented in this paper, which explores microstructural studies of materials used in various fields of engineering, with especial emphasis on concrete technology. Its main aim is to present the range of new applications, in addition to the conventional uses of CT-Scan technology. Based on X-ray absorption, CT generates a visual display of the internal microstructure of a material at micro-range resolutions. In addition to its well-known usage in medicine, the current fields of application of this technology are very extensive. For example, CT is now an essential tool in paleontology that can reveal the internal structure of ancient relics without damaging (in many cases) unique specimens. It is extremely useful in material engineering, when analyzing the internal microstructure of the new and/or improved materials, because the images it generates can then be used to modify the material and further improve its macroscopic behavior. Mechanical engineers use it both in the analysis of internal flaws (i.e. voids, cracks, joints, and planes of weakness) in metals and in the study of composite materials. Likewise, its use among civil engineers extends to microstructural studies of rock and minerals (crack patterns, joints, voids, etc.). The advantages of this powerful tool are similar in concrete technology, because the macroscopic response of concrete components, as with so many other materials, is strongly related to the internal microstructure of the matrix and its internal flaws.

Z-ring membrane anchors associate with cell wall synthases to initiate bacterial cell division.

During the transition from elongation to septation, Escherichia coli establishes a ring-like peptidoglycan growth zone at the future division site. This preseptal peptidoglycan synthesis does not require the cell division-specific peptidoglycan transpeptidase PBP3 or most of the other cell division proteins, but it does require FtsZ, its membrane-anchor ZipA and at least one of the bi-functional transglycosylase-transpeptidases, PBP1A or PBP1B. Here we show that PBP1A and PBP1B interact with ZipA and localise to preseptal sites in cells with inhibited PBP3. ZipA stimulates the glycosyltransferase activity of PBP1A. The membrane-anchored cell division protein FtsN localises at preseptal sites and stimulates both activities of PBP1B. Genes zipA and ftsN can be individually deleted in ftsA* mutant cells, but the simultaneous depletion of both proteins is lethal and cells do not establish preseptal sites. Our data support a model according to which ZipA and FtsN-FtsA have semi-redundant roles in connecting the cytosolic FtsZ ring with the membrane-anchored peptidoglycan synthases during the preseptal phase of envelope growth.

A Novel Laser and Video-Based Displacement Transducer to Monitor Bridge Deflections.

The measurement of static vertical deflections on bridges continues to be a first-level technological challenge. These data are of great interest, especially for the case of long-term bridge monitoring; in fact, they are perhaps more valuable than any other measurable parameter. This is because material degradation processes and changes of the mechanical properties of the structure due to aging (for example creep and shrinkage in concrete bridges) have a direct impact on the exhibited static vertical deflections. This paper introduces and evaluates an approach to monitor displacements and rotations of structures using a novel laser and video-based displacement transducer (LVBDT). The proposed system combines the use of laser beams, LED lights, and a digital video camera, and was especially designed to capture static and slow-varying displacements. Contrary to other video-based approaches, the camera is located on the bridge, hence allowing to capture displacements at one location. Subsequently, the sensing approach and the procedure to estimate displacements and the rotations are described. Additionally, laboratory and in-service field testing carried out to validate the system are presented and discussed. The results demonstrate that the proposed sensing approach is robust, accurate, and reliable, and also inexpensive, which are essential for field implementation.

Application of Industrial Wastes from Chemically Treated Aluminum Saline Slags as Adsorbents.

In this study, industrial wastes, which remain after aluminum extraction from saline slags, were used as adsorbents. The aluminum saline slags were treated under reflux with 2 mol/dm3 aqueous solutions of NaOH, H2SO4, and HCl for 2 h. After separation by filtration, aqueous solutions containing the extracted aluminum and residual wastes were obtained. The wastes were characterized by nitrogen adsorption at -196 °C, X-ray diffraction, scanning electron microscopy, and ammonia pulse chemisorption. The chemical treatment reduced the specific surface area, from 84 to 23 m2/g, and the pore volume, from 0.136 to 0.052 cm3/g, of the saline slag and increased the ammonia-adsorption capacity from 2.84 to 5.22 cm3/g, in the case of acid-treated solids. The materials were applied for the removal of Acid Orange 7 and Acid Blue 80 from aqueous solutions, considering both single and binary systems. The results showed interesting differences in the adsorption capacity between the samples. The saline slag treated with HCl rapidly adsorbed all of the dyes present in solution, whereas the other materials retained between 50 and 70% of the molecules present in solution. The amount of Acid Orange 7 removed by the nontreated material and by the material treated with NaOH increased in the presence of Acid Blue 80, which can be considered as a synergistic behavior. The CO2 adsorption of the solids at several temperatures up to 200 °C was also evaluated under dry conditions. The aluminum saline slag presented an adsorption capacity higher than the rest of treated samples, a behavior that can be explained by the specific sites of adsorption and the textural properties of the solids. The isosteric heats of CO2 adsorption, determined from the Clausius-Clapeyron equation, varied between 1.7 and 26.8 kJ/mol. The wastes should be used as adsorbents for the selective removal of organic contaminants in wastewater treatment.

Unique transcriptional profile of native persisters in Escherichia coli.

Non-dividing persisters, bacteria that can survive in the presence of antibiotics by pausing their metabolic activity, are among the many causes of the refractory nature of bacterial infections. Here we constructed a recombinant Escherichia coli strain that enables to distinguish non-dividing from dividing cell based on Z-ring during cell division. Then, non-dividing cells and dividing cells were successfully separated using a fluorescence activated cell sorter. The sorted non-dividing cells showed significantly higher tolerance toward ofloxacin than dividing cells, which indicates that persisters were concentrated with the methodology. Transcriptional analysis revealed that genes involved in guanosine tetraphosphate synthesis are upregulated in persisters, which represses transcription and DNA replication and leads to ofloxacin tolerance. Lactate dehydrogenase and several ATP-binding cassette transporters were upregulated in persisters to adapt to anaerobic metabolism. In addition, nitrite and dimethyl sulfoxide (DMSO) may be used as reducible substrates for alternative energy generation pathways. Our methodology revealed a unique transcriptional profile of E. coli persisters.