Is the carotenoid production from Phaffia rhodozyma yeast genuinely sustainable? a comprehensive analysis of biocompatibility, environmental assessment, and techno-economic constraints.

Microorganisms, such as yeasts, filamentous fungi, bacteria, and microalgae, have gained significant attention due to their potential in producing commercially valuable natural carotenoids. In recent years, Phaffia rhodozyma yeasts have emerged as intriguing non-conventional sources of carotenoids, particularly astaxanthin and ß-carotene. However, the shift from academic exploration to effective industrial implementation has been challenging to achieve. This study aims to bridge this gap by assessing various scenarios for carotenoid production and recovery. It explores the use of ionic liquids (ILs) and bio-based solvents (ethanol) to ensure safe extraction. The evaluation includes a comprehensive analysis involving Life Cycle Assessment (LCA), biocompatibility assessment, and Techno-Economic Analysis (TEA) of two integrated technologies that utilize choline-based ILs and ethanol (EtOH) for astaxanthin (+ß-carotene) recovery from P. rhodozyma cells. This work evaluates the potential sustainability of integrating these alternative solvents within a yeast-based bioeconomy.

Stress, fear, and anxiety among construction workers: a systematic review.

Objectives: The aim of this review was to assess the possible risk factors arising from working conditions, that could have an impact on the stress, fear, and anxiety of construction workers. Methods: A systematic review was conducted following the PRISMA format in the Pubmed, Cochrane, Web of Science, Scopus, and PsycInfo electronic databases on February 3, 2023, using the following key words: anxiety, stress, fear, and construction workers. Methodological quality was assessed using the critical appraisal tools of the Joanna Briggs Institute. Results: A total of 35 studies were included. The results showed a number of conditioning factors for stress, anxiety, and fear among construction workers such as age, inappropriate safety equipment, safety culture, high workload and long working hours, physical pain, low social support from direct supervisor or co-workers, lack of organizational justice and lack of reward, financial situation, maladaptive coping strategies, and characteristics of the pandemic. Conclusions: There are a number of risk factors related to working conditions, organizations, and individuals that can affect the levels of stress, anxiety, and fear among construction workers, such as age, work hardship, safety culture and, especially, the long hours that construction professionals work. This may lead to an increase in the number of occupational accidents and higher associated fatality rates. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022367724, identifier: CRD42022367724.

Sustainable digital transformation in small and medium enterprises (SMEs): A review on performance.

Small and medium enterprises (SMEs) are responsible for 90% of all business and 50% of employment globally, mostly female jobs. Therefore, measuring SMEs' performance under the digital transformation (DT) through methods that encompass sustainability represents an essential tool for reducing poverty and gender inequality (United Nations Sustainable Development Goals). We aimed to describe and analyze the state-of-art performance evaluations of digital transformation in SMEs, mainly focusing on performance measurement. Also, we aimed to determine whether the tools encompass the three pillars of sustainability (environmental, social, and economic). Through a systematic literature review (SLR), a search on Web of Science (WoS) and Scopus resulted in the acceptance of 74 peer-reviewed papers published until December 2021. Additionally, a bibliometrics investigation was executed. Although there was no time restriction, the oldest paper was published in 2016, indicating that DT is a new research topic with increasing interest. Italy, China, and Finland are the countries that have the most published on the theme. Based on the results, a conceptual framework is proposed. Also, two future research directions are presented and discussed, one for theoretical and another for practical research. Among the theoretical development, it is essential to work on a widely accepted SME definition. Among the practical research, nine directions are identified-e.g., applying big data, sectorial and regional prioritization, cross-temporal investigations etc. Researchers can follow the presented avenues and roads to guide their researchers toward the most relevant topics with the most urgent necessity of investigation.

Oficina de formação bioética para a Estratégia Saúde da Família: perspectivas e olhares dos diferentes atores acerca dos cenários, montagem e espetáculo / Bioethics Training Workshop for Family Health Strategy: perspectives of the different players about scenarios, setup and show / Taller de formación en bioética para la estrategia salud de la familia: perspectivas y miradas de los diferentes actores sobre los escenarios, montaje y espectáculo

A formação dos profissionais de saúde segue em discussão há tempos ­ no Brasil e no mundo ­, assim como as mudanças dos paradigmas sanitários e dos modelos de cuidado em saúde. Com a criação do Sistema Único de Saúde e a implantação da Estratégia de Saúde da Família (ESF) como reorganizadores da atenção em saúde, brotam, neste cenário, questões e problemas bioéticos não vividos anteriormente no âmbito da prática de saúde hospitalar. Este artigo apresenta os resultados da realização de uma oficina de formação em bioética com a participação de 130 pessoas (128 profissionais da ESF no município de Viçosa, Minas Gerais, e dois convidados), promovida pela integração da universidade com o serviço de saúde local. Os referenciais utilizados incluíram o pluralismo metodológico, o trabalho em pequenos grupos, a aprendizagem significativa e o uso da arte para a construção das competências em bioética. Os resultados verificados foram otimistas quanto à efetividade da ação, tanto na ótica dos profissionais da ESF quanto dos participantes (facilitadores e docentes envolvidos), promovendo-se uma construção coletiva de saberes para a práxis.

The training of health professionals has been a point of discussion for a long time in Brazil and around the world, as well as changes in health paradigms and health care models. With the merger of the National Health System and the implementation of the Family Health Strategy (FHS) as organizer of health care, issues and problems emerged, which were not previously thought about in the context of health and hospital practice, mainly reflections on ethical and bioethical aspects. This paper presents the results of conducting a training workshop on bioethics with the participation of 130 people (128 FHS professionals in Viçosa, Minas Gerais and two guests), sponsored by the university's integration with the local health service, based on the use of methodological pluralism, small group work, learning and meaningful use of art for the construction of expertise in bioethics. Actual outcomes were optimistic about the effectiveness of the action, from the viewpoint of both the FHS professionals and participants (facilitators and professors involved), promoting a collective construction of knowledge for practice.

La formación de los profesionales de la salud es objeto de debate desde hace mucho tiempo - en Brasil y en el mundo -, así como los cambios de paradigmas y modelos de salud para el cuidado de la salud. Con la creación del Sistema Único de Salud (SUS) y de la aplicación de la Estrategia Salud de la Familia (ESF) como de reorganizadores cuidado de la salud, surgen, en este escenario, los problemas y las cuestiones de bioética que no se vivieron dentro de la práctica de la salud del hospital. Este artículo presenta los resultados de la realización de una capacitación sobre la bioética con la participación de 130 personas (128 profesionales de la ESF en Viçosa, Minas Gerais y dos invitados), promovido por la integración de la universidad con el servicio de salud local. Los puntos de referencia utilizados incluyen el pluralismo metodológico, el trabajo en pequeños grupos, el aprendizaje significativo y el uso del arte para la construcción de capacidades en bioética. Los resultados observados se mostraron optimistas acerca de la efectividad de la acción, tanto desde el punto de vista de los profesionales de la ESF, y los participantes (facilitadores y profesores involucrados), la promoción de una construcción colectiva de conocimiento a la práctica.

Self-regulation in toddlers and the emergence of pre-academic disparities.

A growing body of research has examined how children's self-regulation during early and middle childhood mediates SES disparities in academic achievement. Evidence suggests that these self-regulation skills begin developing even earlier, during the toddler years, but more work is needed examining how different measures of self-regulation relate to key constructs such as socioeconomic status (SES) and toddlers' pre-academic skills. In this online study, we examine multiple approaches to measuring self-regulation using confirmatory factor analyses and assess the extent to which self-regulatory skills help explain SES differences in early math and language skills among a sample of 158 two- and three-year-old children. Self-regulation was assessed through a battery of parent- and examiner-ratings. Children's counting, cardinality, and vocabulary skills were measured online through direct assessments and parent surveys. Two self-regulation factors emerged representing parent-reported and observational measures, and only observational measures of self-regulation mediated associations between SES and children's math and language skills. Parent-reported self-regulation was not uniquely related to SES or children's pre-academic skills, underscoring the need for careful consideration of how self-regulation is measured among toddlers when examining its associations with pre-academic skills.

Foraging costs drive within-colony spatial segregation in shearwaters from two contrasting environments in the North Atlantic Ocean.

Foraging spatial segregation is frequent in central-place foragers during the breeding season, but very few studies have investigated foraging spatial segregation between adjacent sub-colonies. Here, we assessed for within-colony differences in the at-sea distribution, habitat use, trophic ecology and chick growth data of two Calonectris colonies differing in size, and breeding in two different environments in the North Atlantic Ocean. For this, we GPS tracked 52 Cory's shearwaters (Calonectris borealis) breeding in 2 small sub-colonies at Berlenga Island (Portugal) and 59 Cape Verde shearwaters (Calonectris edwardsii) breeding in 2 sub-colonies differing greatly in size at Raso Islet (Cabo Verde), over 2 consecutive breeding seasons (2017-2018), during chick-rearing. Cory's shearwaters from the two sub-colonies at Berlenga Island broadly overlapped in repeatedly used foraging patches close to the colony. In contrast, the foraging distribution of Cape Verde shearwaters was partially segregated in the colony surroundings, but overlapped at distant foraging areas off the west coast of Africa. Despite spatial segregation close to the colony, Cape Verde shearwaters from both sub-colonies departed in similar directions, foraged in similar habitats and exhibited mostly short trips within the archipelago of Cabo Verde. These results, corroborated with similar trophic ecology and chick growth rates between sub-colonies, support the idea that foraging spatial segregation in the colony surroundings was not likely driven by interference competition or directional bias. We suggest that high-quality prey patches are able to shape travel costs and foraging distribution of central-place foragers from neighbouring sub-colonies.

Plotter Cut Stencil Masks for the Deposition of Organic and Inorganic Materials and a New Rapid, Cost Effective Technique for Antimicrobial Evaluations.

Plotter cutters in stencil mask prototyping are underutilized but have several advantages over traditional MEMS techniques. In this paper we investigate the use of a conventional plotter cutter as a highly effective benchtop tool for the rapid prototyping of stencil masks in the sub-250 µm range and characterize patterned layers of organic/inorganic materials. Furthermore, we show a new diagnostic monitoring application for use in healthcare, and a potential replacement of the Standard Kirby-Bauer Diffusion Antibiotic Resistance tests was developed and tested on both Escherichia coli and Xanthomonas alfalfae as pathogens with Oxytetracycline, Streptomycin and Kanamycin. We show that the reduction in area required for the minimum inhibitory concentration tests; allow for three times the number of tests to be performed within the same nutrient agar Petri dish, demonstrated both theoretically and experimentally resulting in correlations of R ≈ 0.96 and 0.985, respectively for both pathogens.

Subacute toxicity assessment of biobased ionic liquids in rats.

Ionic liquids (ILs) derived from compounds obtained from natural sources, such as fatty acids (FAs) have attracted the interest of the scientific and industrial communities because of their sustainable appeal and possible low toxic effects or nontoxicity. These aspects open new perspective of applications in other fields, which demands a better comprehension of their toxicity. This work evaluated the subacute toxicity of bis(2-hydroxyethyl)ammonium carboxylates in Wistar rats, considering the alkyl chain length of FAs (capric and oleic acids), and the concentration (0.16%, 1.6% or 3.2%, wIL/wOil) of ILs added in diets. The blood serum of the rats was evaluated in relation to total cholesterol, triglycerides, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and γ-glutamyl transferase. Lipid peroxidation was determined in plasma, liver and kidney tissues by determining the level of thiobarbituric acid reactive substances. Histological analyses of the liver and kidney tissues were performed in order to evaluate morphological changes. No signal of toxicity was observed according to lipid peroxidation. Triglycerides increased with the increasing of the concentration and alkyl chain length of the IL, but no difference in serum level of lipid peroxidation was observed. This behavior may be attributed to the amphiphilic nature of FAs based ILs, which might facilitate lipid digestion. However, more studies are necessary in order to understand such behavior. Therefore, the synthesis of ILs from FAs, has been evaluated as a strategy to produce compounds with low or without toxicity for the agro-food, pharmaceutical or cosmetic industries.

Sigilo, confidencialidade e privacidade: perspectivas pedagógicas na Estratégia Saúde da Família / Secrecy, confidentiality and privacy: educational perspectives in the Family Health Strategy / El secreto, la confidencialidad y la privacidad: perspectivas en el proceso educativo sobre la Estrategia de Salud de la Familia

A investigação dos problemas bioéticos na Estratégia Saúde da Família (ESF) permanece, ainda, como tema negligenciado nas publicações acadêmicas contemporâneas, a despeito das candentes questões que se apresentam nessa esfera da atenção à saúde. Nesse âmbito, elementos atinentes à relação entre usuários e profissionais de saúde ganham relevância. O estudo dessa temática é mote do presente artigo, no qual são apresentados resultados obtidos junto aos profissionais da ESF do município de Viçosa/MG, durante a realização de oficina de formação em bioética e Atenção Primária à Saúde ­ enfatizando as conversações sobre o sigilo, a privacidade e a confidencialidade ­ desenvolvidas ao longo do processo pedagógico. (AU)

The investigation of bioethical issues in the Family Health Strategy (FHS) still remains a neglected theme in contemporary scholarly literature, despite the pressing issues that arise in this sphere of health care. In this context, elements related to the relationship between users and health professionals gain relevance. The study of this theme is the mote of this article, in which results obtained from FHS professionals in the county of Viçosa/MG, while they trained and attended a workshop on bioethics and Primary Health Care, are presented ­ emphasizing conversations regarding secrecy, privacy and confidentiality developed throughout the educational process. (AU)

La investigación de las cuestiones de bioética en la Estrategia de Salud de la Familia (ESF) todavía permanece como tema descuidado en las publicaciones académicas contemporáneas, a pesar de los temas candentes que se plantean en esta esfera de la atención a la salud. En este contexto, sobre la relación entre los usuarios y profesionales de la salud se convierten en elementos más importantes. El estudio de este tema es el tema de este artículo, en el que los resultados obtenidos se presentan junto a los profesionales de la ESF de la ciudad de Viçosa/MG, mientras la realización de la formación en bioética y taller de formación primaria de salud ­ haciendo hincapié en las conversaciones sobre el secreto, la privacidad y confidencialidad ­ desarrollado durante el proceso educativo. (AU)

Indications for stent omission after ureteroscopic lithotripsy defined: A single-institution experience with cost analysis.

Objectives: To report on our experience with the use of an evidence-based algorithm defining specific indications for stent omission (SO) after ureteroscopic lithotripsy (URSL), as stent placement has been associated with increased cost and morbidity and indications for SO in the setting of uncomplicated ureteroscopy have been proposed but remain vague. Patients and methods: Indications for SO were defined as per the attached figure, data from URSL procedures performed from January 2016 to September 2017 were collected. For procedures eligible for SO, preoperative and intraoperative factors were recorded including: stone burden, presence of preoperative stent, procedure time, access sheath use, and whether SO was performed. Morbidity data were reviewed including: postoperative events, patient telephone calls for bothersome symptoms, unplanned return visits, and admissions within 30 days. Results: In all, 250 URSL procedures were performed during the study period, and 106 (42.4%) were eligible for SO. SO was performed in 60 (24.0%) cases reflecting a 56.7% compliance with the algorithm. There were no readmissions or re-operations within 30 days for the SO group. Lower postoperative event rates were noted in the SO group (16.7% vs 34.8%, P = 0.03), unplanned return visits (8.3% vs 17.4%, P = 0.16) and 30-day readmission rates (0.0% vs 6.5%, P = 0.08) were also lower in the SO group, although they did not reach statistical significance. Analysis also demonstrated a protective effect of SO on unplanned return visits (odds ratio 0.43, 95% confidence interval 0.13-1.42, P = 0.17), although this was not statistically significant. No statistically significant associations were noted between postoperative events and stone burden, procedure time, or presence of preoperative stent. Conclusions: We provide an algorithm defining indications for SO. SO is safe in a significant portion of URSL procedures, and SO appears to decrease postoperative events when performed judiciously. Abbreviations: IQR: interquartile range; LUTS: lower urinary tract symptoms; OR, odds ratio; SO: stent omission; URSL: ureteroscopic lithotripsy; YAG: yttrium-aluminium-garnet.

Improving the cost effectiveness of enhanced green fluorescent protein production using recombinant Escherichia coli BL21 (DE3): Decreasing the expression inducer concentration.

Green fluorescent protein (GFP) is a globular protein used as biosensor and biomarker in medical and industrial fields. However, due to the expensive production costs of expressing proteins using high-cost inducers like isopropyl-ß-d-1-thiogalactopyranoside (IPTG), the number of GFP applications are still scarce. This work studied the production of enhanced GFP (EGFP) using Escherichia coli BL21 (DE3) [pLysS; pET28(a)], aiming to increase its yield and reduce costs. First, the influence of agitation rate, induction time, and concentration of IPTG in the production of EGFP was evaluated, but only the first two parameters were significant. Subsequently, aiming to reduce costs related to the use of inducer, the IPTG concentration (0.005, 0.010, and 0.025 mM) was decreased and, interestingly, the production levels were maintained or increased. These results show that a proper choice of production conditions, particularly through the decrease of inducer concentration, is effective to reduce the upstream production costs and guarantee high EGFP expression.

Ureteral stenting practices following routine ureteroscopy: an international survey.

PURPOSE: Stent omission after routine ureteroscopy (rtURS) is accepted by current guidelines and may result in decreased patient morbidity and treatment costs. In a value-based healthcare model, the added morbidity and cost of routine stent placement may be scrutinized. Furthermore, data are limited on urologist cost knowledge and it is effect on ureteral stent placement. As such, we seek to describe ureteral stenting practices and urologist cost knowledge amongst US and non-US-based urologists. METHODS: The ureteroscopic practice patterns and cost awareness of members of the Endourological Society were surveyed using an international email listserv. Respondents were grouped by practice location (US vs non-US). Logistic regression was used to evaluate the associations of surgeon practice location with stenting practices. RESULTS: 233 completed responses were received with a response rate of 13.5%. Results revealed that 55% and 71% of respondents reported ureteral stent insertion after rtURS more than 75% of the time for ureteral and renal stones, respectively. Reporting stent insertion following more than 75% of rtURS was more common among US participants for both ureteral and renal stones. Overall, reported cost knowledge was high, but lower among US participants. On multivariable analysis, US respondents were more likely to place ureteral stents after rtURS for ureteral stones more than 75% of the time when compared to those abroad (OR 3.43 p < 0.01). CONCLUSION: Ureteral stenting after rtURS is over utilized in the US compared to other countries. While this phenomenon is multifactorial in nature, cost knowledge may be under recognized as a determinant of ureteral stent placement following rtURS.

Economic evaluation of the primary recovery of tetracycline with traditional and novel aqueous two-phase systems.

Antibiotics are a key pharmaceutical to inhibit growth or kill microorganisms. They represent a profitable market and, in particular, tetracycline has been listed as an essential medicine by the WHO. Therefore it is important to improve their production processes. Recently novel and traditional aqueous two-phase systems for the extraction have been developed with positive results. The present work performs an economic analysis of the production and recovery of tetracycline through the use of several ATPS through bioprocess modeling using specialized software (BioSolve, Biopharm Services Ltd, UK) to determine production costs per gram (CoG/g). First, a virtual model was constructed using published data on the recovery of tetracycline and extended to incorporate uncertainties. To determine how the model behaved, a sensitivity analysis and Monte Carlo simulations were performed. Results showed that ATPS formed by cholinium chloride/K3PO4 was the best option to recover tetracycline, as it had the lowest CoG/g (US$ 672.83/g), offered the highest recovery yield (92.42%), second best sample input capacity (45% of the ATPS composition) and one of the lowest materials contribution to cost. The ionic liquid-based method of ATPS is a promising alternative for recovering tetracycline from fermentation broth.

A critical assessment of the mechanisms governing the formation of aqueous biphasic systems composed of protic ionic liquids and polyethylene glycol.

An extensive study on the formation of aqueous biphasic systems (ABS) using aqueous solutions of protic ionic liquids (PILs) and polyethylene glycol (PEG) was performed in order to understand the mechanisms underlying the phase separation. Aqueous solutions of PEG polymers with different molecular weights (600, 1000, 2000, and 3400 g mol-1) and several N-alkyl-, dialkyl-, and trialkyl-ammonium salts of acetate, propanoate, butanoate, hexanoate and octanoate were prepared and their ability to form ABS at several temperatures assessed. The ternary liquid-liquid phase diagrams were determined at several temperatures, as well as binary PIL (or salt)-PEG-1000 and salt-water solubility data to better clarify the mechanisms responsible for the phase separation. All data gathered indicate that the formation of PEG-PIL-based ABS is mainly governed by the PIL-PEG mutual interactions, where PILs with a higher solubility in the polymer exhibit a lower aptitude to form ABS displaying thus a smaller biphasic region, for which a direct correlation was identified. The effects of the molecular weight and temperature of the polymer were also addressed. The increase of the PEG hydrophobicity or molecular weight favours the phase separation, whereas the effect of temperature was found to be more complex and dependent on the nature of the PIL, with an increase or decrease of the biphasic regime with an increase in temperature.

Assessment of genetic diversity in Brazilian barley using SSR markers.

Barley is a major cereal grown widely and used in several food products, beverage production and animal fodder. Genetic diversity is a key component in breeding programs. We have analyzed the genetic diversity of barley accessions using microsatellite markers. The accessions were composed of wild and domesticated barley representing genotypes from six countries and three breeding programs in Brazil. A total of 280 alleles were detected, 36 unique to Brazilian barley. The marker Bmag120 showed the greatest polymorphism information content (PIC), with the highest mean value found on chromosome three, and the lowest on chromosomes four and six. The wild accessions presented the highest diversity followed by the foreign genotypes. Genetic analysis was performed using Principal Coordinates Analysis, UPGMA clustering, and Bayesian clustering analysis implemented in Structure. All results obtained by the different methods were similar. Loss of genetic diversity has occurred in Brazilian genotypes. The number of alleles detected in genotypes released in 1980s was higher, whereas most of the cultivars released thereafter showed lower PIC and clustered in separate subgroups from the older cultivars. The use of a more diverse panel of genotypes should be considered in order to exploit novel alleles in Brazilian barley breeding programs.

A micro-extraction technique using a new digitally controlled syringe combined with UHPLC for assessment of urinary biomarkers of oxidatively damaged DNA.

The formation of reactive oxygen species (ROS) within cells causes damage to biomolecules, including membrane lipids, DNA, proteins and sugars. An important type of oxidative damage is DNA base hydroxylation which leads to the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 5-hydroxymethyluracil (5-HMUra). Measurement of these biomarkers in urine is challenging, due to the low levels of the analytes and the matrix complexity. In order to simultaneously quantify 8-oxodG and 5-HMUra in human urine, a new, reliable and powerful strategy was optimised and validated. It is based on a semi-automatic microextraction by packed sorbent (MEPS) technique, using a new digitally controlled syringe (eVol(®)), to enhance the extraction efficiency of the target metabolites, followed by a fast and sensitive ultrahigh pressure liquid chromatography (UHPLC). The optimal methodological conditions involve loading of 250 µL urine sample (1:10 dilution) through a C8 sorbent in a MEPS syringe placed in the semi-automatic eVol(®) syringe followed by elution using 90 µL of 20% methanol in 0.01% formic acid solution. The obtained extract is directly analysed in the UHPLC system using a binary mobile phase composed of aqueous 0.1% formic acid and methanol in the isocratic elution mode (3.5 min total analysis time). The method was validated in terms of selectivity, linearity, limit of detection (LOD), limit of quantification (LOQ), extraction yield, accuracy, precision and matrix effect. Satisfactory results were obtained in terms of linearity (r(2) > 0.991) within the established concentration range. The LOD varied from 0.00005 to 0.04 µg mL(-1) and the LOQ from 0.00023 to 0.13 µg mL(-1). The extraction yields were between 80.1 and 82.2 %, while inter-day precision (n = 3 days) varied between 4.9 and 7.7 % and intra-day precision between 1.0 and 8.3 %. This approach presents as main advantages the ability to easily collect and store urine samples for further processing and the high sensitivity, reproducibility, and robustness of eVol(®)MEPS combined with UHPLC analysis, thus retrieving a fast and reliable assessment of oxidatively damaged DNA.

[Myocardial viability assessment]. / Avaliação da viabilidade miocárdica.

The prognosis for patients with chronic coronary artery disease and severe left ventricular dysfunction is poor, despite advances in different therapies. The assessment of myocardial viability has become an important aspect of the diagnosis, prognosis and management of patients with ischemic cardiomyopathy. Patients with left ventricular dysfunction, with a substantial amount of severely ischemic myocardium are at highest risk, and are likely to benefit from coronary revascularization. Patients with predominantly scar tissue should be treated medically. Multiple imaging techniques have been developed to assess viable and nonviable myocardium by evaluating perfusion, cell membrane integrity, glucose metabolism, fibrosis and contractile reserve. PET FDG-F18, myocardial perfusion scintigraphy (with (201)Tl and (99m)Tc), dobutamine stress echocardiography and more recently magnetic resonance have been extensively evaluated for assessment of viability and prediction of clinical outcome after coronary revascularization. In general, nuclear imaging techniques have a higher sensitivity for the detection of viability, whereas techniques evaluating contractile reserve have higher specificity (with lower sensitivity). Magnetic resonance has a high diagnostic accuracy for assessment of the transmural extent of myocardial scar tissue. The aim of this article is to review the role of Nuclear Medicine in assessing myocardial viability and risk stratification in patients with advanced left ventricular dysfunction, and to compare it with other imaging modalities.