An Upgrade on the Surveillance System of SARS-CoV-2: Deployment of New Methods for Genetic Inspection.

SARS-CoV-2 variants surveillance is a worldwide task that has been approached with techniques such as Next Generation Sequencing (NGS); however, this technology is not widely available in developing countries because of the lack of equipment and limited funding in science. An option is to deploy a RT-qPCR screening test which aids in the analysis of a higher number of samples, in a shorter time and at a lower cost. In this study, variants present in samples positive for SARS-CoV-2 were identified with a RT-qPCR mutation screening kit and were later confirmed by NGS. A sample with an abnormal result was found with the screening test, suggesting the simultaneous presence of two viral populations with different mutations. The DRAGEN Lineage analysis identified the Delta variant, but there was no information about the other three mutations previously detected. When the sequenced data was deeply analyzed, there were reads with differential mutation patterns, that could be identified and classified in terms of relative abundance, whereas only the dominant population was reported by DRAGEN software. Since most of the software developed to analyze SARS-CoV-2 sequences was aimed at obtaining the consensus sequence quickly, the information about viral populations within a sample is scarce. Here, we present a faster and deeper SARS-CoV-2 surveillance method, from RT-qPCR screening to NGS analysis.

Reduction Over Condensation of Carbonyl Compounds Through a Transient Hemiaminal Intermediate Using Hydrazine.

Reduction of carbonyl moieties to the corresponding alcohol using simply hydrazine hydrate has been considerably unfeasible until now due to the well-known condensation reaction. However, herein, we report that using an excess of 20-fold equivalents, the reduction proceeds in excellent yields. 1H NMR study of the reaction and density functional theory (DFT) calculations indicate that the final fate of the hemiaminal intermediate is crucial to obtain the alcohol or the hydrazone.

Vessel-specific quantification of absolute myocardial blood flow, myocardial flow reserve and relative flow reserve by means of fused dynamic 13NH3 PET and CCTA: Ranges in a low-risk population and abnormality criteria.

OBJECTIVES: The goal of the present work is to present a novel methodology for the extraction of MBF, MFR and RFR along coronary arteries by means of multimodality image fusion of dynamic PET and CCTA images. BACKGROUND: FFR is the reference standard to identify flow-limiting lesions, but its invasiveness limits broad application. New noninvasive methodologies are warranted to stratify patients and guide treatment. METHODS: A group of 16 low-risk CAD subjects who underwent both 13NH3 PET and CCTA were analyzed. Image fusion techniques were employed to align the studies and CCTA-derived anatomy used to identify coronaries trajectories. MBF was calculated by means of a 1-tissue compartmental model for the standard vascular territories and along patient-specific vessel paths from the base to the apex of the heart. RESULTS: Low-risk ranges for MBF. MFR and RFR for LAD, LCX and rPDA were computed for the entire cohort and separated by gender. Computed low-risk ranges were used to assess a prospective patient with suspected CAD. CONCLUSIONS: Our vessel-specific functional indexes and 3D displays offer promise to more closely replicate what is commonly performed during a catheterization session and have the potential of providing effective noninvasive tools for the identification of flow-limiting lesions and image-guided therapy.

Lightweight Authentication Protocol for M2M Communications of Resource-Constrained Devices in Industrial Internet of Things.

The Industrial Internet of Things (IIoT) consists of sensors, networks, and services to connect and control production systems. Its benefits include supply chain monitoring and machine failure detection. However, it has many vulnerabilities, such as industrial espionage and sabotage. Furthermore, many IIoT devices are resource-constrained, which impedes the use of traditional security services for them. Authentication allows devices to be confident of each other's identity, preventing some security attacks. Many authentication protocols have been proposed for IIoT; however, they have high computing requirements not viable to resource-constrained devices, or they have been found insecure. In this paper, an authentication protocol for resource-constrained IIoT devices is proposed. It is based on the lightweight operations xor, addition, and subtraction, and a hash function. Also, only four messages are exchanged between the principals to authenticate. It has a low execution-time and communication-cost. Its security was successfully assessed with the formal methods Automated Validation of Internet Security Protocols and Applications (AVISPA) tool and Burrows-Abadi-Needham (BAN) logic, together with an informal analysis of its resistance to known attacks. Its performance and security were compared with state-of-the-art protocols, resulting in a good performance for resource-constrained IIoT devices, and higher security similar to computational expensive schemes.

Default Mode Network, Meditation, and Age-Associated Brain Changes: What Can We Learn from the Impact of Mental Training on Well-Being as a Psychotherapeutic Approach?

Aging is a physiological process accompanied by cognitive decline, principally in memory and executive functions. Alterations in the connectivity of the default mode network (DMN) have been found to participate in cognitive decline, as well as in several neurocognitive disorders. The DMN has antisynchronic activity with attentional networks (task-positive networks (TPN)), which are critical to executive function and memory. Findings pointing to the regulation of the DMN via activation of TPN suggest that it can be used as a strategy for neuroprotection. Meditation is a noninvasive and nonpharmacological technique proven to increase meta-awareness, a cognitive ability which involves the control of both networks. In this review, we discuss the possibility of facilitating healthy aging through the regulation of networks through meditation. We propose that by practicing specific types of meditation, cognitive decline could be slowed, promoting a healthy lifestyle, which may enhance the quality of life for the elderly.

A Lightweight Cipher Based on Salsa20 for Resource-Constrained IoT Devices.

The Internet of Things (IoT) paradigm envisions a world where everyday things interchange information between each other in a way that allows users to make smarter decisions in a given context. Even though IoT has many advantages, its characteristics make it very vulnerable to security attacks. Ciphers are a security primitive that can prevent some of the attacks; however, the constrained computing and energy resources of IoT devices impede them from implementing current ciphers. This article presents the stream cipher Generador de Bits Pseudo Aleatorios (GBPA) based on Salsa20 cipher, which is part of the eSTREAM project, but designed for resource-constrained IoT devices of Class 0. GBPA has lower program and data memory requirements compared with Salsa20 and lightweight ciphers. These properties allow low-cost resource-constrained IoT devices, 29.5% of the embedded systems in the market, to be able to implement a security service that they are currently incapable of, to preserve the user's data privacy and protect the system from attacks that could damage it. For the evaluation of its output, three statistical test suites were used: NIST Statistical Test Suite (STS), DIEHARD and EACirc, with good results. The GBPA cipher provides security without having a negative impact on the computing resources of IoT devices.

Evaluación clínica y ultrasonográfica de la glándula tiroides en pacientes con artritis reumatoide.

Introducción: Los pacientes con artritis reumatoide pueden desarrollar enfermedad tiroidea autoinmune (ETA), cuyo diagnóstico clínico puede ser difícil debido a que ambas comparten síntomas como artralgias, mialgias, rigidez matutina o fatiga. Objetivo: Determinar la prevalencia de ETA en pacientes con artritis reumatoide. Método: Estudio transversal que incluyó 78 pacientes con artritis reumatoide y 81 controles clínicamente sanos pareados por edad y sexo. A ambos grupos se realizó cuantificación de anticuerpos antitiroideos, pruebas de función tiroidea, ultrasonido y biopsia de glándula tiroides cuando la puntuación de Thyroid Imaging Reporting and Data System (TIRADS) fue ≥ 4. Resultados: 24.4 % de los pacientes con artritis reumatoide presentó hipotiroidismo (p = 0.003) y altos títulos de anticuerpos antitiroideos versus controles clínicamente sanos; 53 % de los ultrasonidos tiroideos resultó normal en pacientes hipotiroideos; en pacientes con artritis reumatoide positivos para anticuerpos antitiroideos se encontró perfusión incrementada en 40 %. Los casos clasificados como TIRADS 4 fueron enviados a aspiración, con resultado histopatológico benigno. Conclusiones: Se demostró el valor clínico agregado de la evaluación tiroidea en pacientes con artritis reumatoide, conforme a la prevalencia de hipotiroidismo subclínico, positividad de anticuerpos antitiroideos y anomalías en el ultrasonido independientes de la función tiroidea normal o alterada. Introduction: Patients with rheumatoid arthritis can develop autoimmune thyroid disease (ATD), the clinical diagnosis of which can be difficult because both entities share symptoms such as arthralgia, myalgia, morning stiffness or fatigue. Objective: To determine the prevalence of ATD in patients with rheumatoid arthritis. Method: Cross-sectional study that included 78 patients with rheumatoid arthritis and 81 clinically healthy controls matched by age and gender. Both groups underwent anti-thyroid antibodies quantification, thyroid function tests, thyroid ultrasound and thyroid gland biopsy when the Thyroid Imaging Reporting and Data System (TIRADS) score was ≥ 4. Results: Hypothyroidism was found in 24.4% of patients with rheumatoid arthritis (p = 0.003), as well as high titers of anti-thyroid antibodies versus clinically healthy controls; 53% of thyroid ultrasounds were normal in hypothyroid patients, and increased perfusion was found in 40% of rheumatoid arthritis patients who tested positive for anti-thyroid antibodies. Cases classified as TIRADS 4 underwent aspiration with benign histopathological results. Conclusions: Thyroid assessment added clinical value was demonstrated in patients with rheumatoid arthritis, according to the prevalence of subclinical hypothyroidism, anti-thyroid antibodies positivity and ultrasound abnormalities, regardless of normal or altered thyroid function.

[Hyperleptinemia associated with ischemic stroke]. / Hiperleptinemia asociada a evento vascular cerebral isquémico (EVCi).

INTRODUCTION: The major risk factors for stroke are obesity, diabetes mellitus, systemic arterial hypertension (SAH) and dyslipidemia. In 1994 leptin was identifies as adipokine produced by adipose tissue. Its main action is the regulation of energy balance. Currently, hyperleptinemia is associated with cardiovascular disease. OBJECTIVE: To determine the association between serum leptin and stroke in patients with SAH. METHODS: We determined serum leptin in subjects with stroke and SAH, and compared this with patients with SAH without stroke. We calculated Student t, χ², and odds ratio (OR) for quantitative and qualitative variables. RESULTS: 60 subjects were recruited, 30 subjects per group. Considering a value>3.93 ng/ml as hyperleptinemia, it also was found a t=2.8 (p=0.007), and χ² with one degree of freedom of 10.82 (p=0.001), obtaining an OR of 3.05 for the development of stroke in the presence of elevated leptin (95% CI: 0.9-9.6; p=0.05). CONCLUSIONS: Hyperleptinemia is more common in patients with stroke than in those without this condition. But the question remains whether hyperleptinemia is a stroke risk factor or protective factor.

Possible involvement of the sco2127 gene product in glucose repression of actinorhodin production in Streptomyces coelicolor.

Streptomyces coelicolor mutants resistant to 2-deoxyglucose are insensitive to carbon catabolite repression (CCR). Total reversion to CCR sensitivity is observed by mutant complementation with a DNA region harboring both glucose kinase glkA gene and the sco2127 gene. The sco2127 is located upstream of glkA and encodes a putative protein of 20.1 kDa. In S. coelicolor, actinorhodin production is subject to glucose repression. To explore the possible involvement of both SCO2127 and glucose kinase (Glk) in the glucose sensitivity of actinorhodin production, this effect was evaluated in a wild-type S. coelicolor A3(2) M145 strain and a sco2127 null mutant (Δsco2127) derived from this wild-type strain. In comparison with strain M145, actinorhodin production by the mutant was insensitive to glucose repression. Under repressive conditions, only minor differences were observed in glucose utilization and Glk production between these strains. SCO2127 was detected mainly during the first 36 h of fermentation, just before the onset of antibiotic production, and its synthesis was not related to a particular carbon source. The glucose sensitivity of antibiotic production was restored to wild-type phenotype by transformation with an integrative plasmid containing sco2127. Our results support the hypothesis that SCO2127 is a negative regulator of actinorhodin production and suggest that the effect is independent of Glk.

Personal exposures to asbestos fibers during brake maintenance of passenger vehicles.

INTRODUCTION: Brake linings and brake pads are among the asbestos-containing products that are readily available in Colombia. When sold separated from their support, brake linings require extensive manipulation involving several steps that include drilling, countersinking, riveting, bonding, cutting, beveling, and grinding. Without this manipulation, brake linings cannot be installed in a vehicle. The manipulation process may release asbestos fibers, which may expose brake mechanics to the fibers. METHODS: Three brake repair shops located in Bogotá (Colombia) were sampled for 3 or 4 consecutive days using US National Institute for Occupational Safety and Health (NIOSH) methods 7400 and 7402. Standard procedures for quality control were followed during the sampling process, and asbestos samples were analyzed by an American Industrial Hygiene Association accredited laboratory. Personal samples were collected to assess full-shift and short-term exposures. Area samples were also collected close to the brake-lining manipulation equipment and within office facilities. Activities were documented during the sampling process. RESULTS: Using Phase Contrast Microscopy Equivalent counts to estimate air asbestos concentrations, all personal samples [i.e. 8-h time-weighted averages (TWAs) and 30-min personal samples] were in compliance with the US Occupational Safety and Health Administration standards. Personal asbestos concentrations based on transmission electron microscopy counts were extremely high, ranging from 0.006 to 3.493 f cm(-3) for 8-h TWA and from 0.015 to 8.835 f cm(-3) for 30-min samples. All asbestos fibers detected were chrysotile. Cleaning facilities and grinding linings resulted in the highest asbestos exposures based on transmission electron microscopy counts. There were also some samples that did not comply with the NIOSH's recommended exposure limits. CONCLUSION: The results indicate that the brake mechanics sampled are exposed to extremely high asbestos concentrations (i.e. based on transmission electron microscopy counts), suggesting that this occupational group could be at excess risk of asbestos-related diseases.

Case Report: Splanchnic Vein Thrombosis as a Complication of Necrotizing Acute Pancreatitis in a Pediatric Patient.

Splanchnic vein thrombosis is an unusual manifestation of venous thromboembolism and includes portal vein thrombosis, mesenteric veins thrombosis, splenic vein thrombosis, and the Budd-Chiari syndrome. The most common risk factors include hematologic and autoimmune disorders, hormonal therapy, liver cirrhosis, solid abdominal cancer, recent abdominal surgery, and abdominal infections or inflammatory conditions, such as pancreatitis. Splanchnic vein thrombosis in acute pancreatitis is most commonly associated with the severe form of the disease and pancreatic necrosis. This report describes a case of splanchnic vein thrombosis as a complication of necrotizing acute pancreatitis in a pediatric patient. Splanchnic vein thrombosis was incidentally detected on contrast-enhanced computed tomography to assess the pancreas. There was no evidence of prior risk factors for the thrombotic condition. The patient was treated with anticoagulation and showed complete resolution after recovery from necrotizing acute pancreatitis, at a 16-month follow-up. The complication of necrotizing acute pancreatitis with splanchnic vein thrombosis in pediatric age is a rare presentation.

Interaction of SCO2127 with BldKB and its possible connection to carbon catabolite regulation of morphological differentiation in Streptomyces coelicolor.

In Streptomyces coelicolor, the sco2127 gene is located upstream of the gene encoding for glucose kinase. This region restores sensitivity to carbon catabolite repression (CCR) of Streptomyces peucetius var. caesius mutants, resistant to 2-deoxyglucose (Dog(R)). In order to search for the possible mechanisms behind this effect, sco2127 was overexpressed and purified for protein-protein interaction studies. SCO2127 was detected during the late growth phase of S. coelicolor grown in a complex media supplemented with 100 mM glucose. Pull-down assays using crude extracts from S. coelicolor grown in the same media, followed by far-western blotting, allowed detection of two proteins bound to SCO2127. The proteins were identified by MALDI-TOF mass spectrometry as SCO5113 and SCO2582. SCO5113 (BldKB) is a lipoprotein ABC-type permease (∼66 kDa) involved in mycelium differentiation by allowing the transport of the morphogenic oligopeptide Bld261. SCO2582, is a putative membrane metalloendopeptidase (∼44 kDa) of unknown function. In agreement with the possible role of SCO2127 in mycelium differentiation, delayed aerial mycelium septation and sporulation was observed when S. coelicolor A3(2) was grown in the presence of elevated glucose concentrations (100 mM), an effect not seen in a Δ-sco2127 mutant derived from it. We speculate that SCO2127 might represent a key factor in CCR of mycelium differentiation by interacting with BldKB.

Biomechanical anchorage evaluation of mini-implants treated with sandblasting and acid etching in orthodontics.

PURPOSE: The purpose of this study was to assess the stability of sandblasted and acid-etched miniscrew implants based on orthodontic mechanics for space closure after tooth extraction. MATERIALS AND METHODS: Twenty-four orthodontic mini-implants were placed in 13 patients, for a skeletal anchorage purpose, all prepared by the manufacturer (3M Unitek-IMTEC Ortho USA) with sandblasting and acid treatment. Anchorage measurements were made on occlusal radiographs, on a monthly basis in a 6-month period. RESULTS: All the mini-implants were effective for the clinical trial; but 65% of the mini-implants, after been loaded, showed up to 1 degree, or less, of displacement, while 35% showed ≥2 degrees shift. The mandible mini-implants resulted in a smaller amount of displacement than the ones located in the maxilla. The ones located at the anterior maxilla displaced less than the posterior. The best results were obtained with the 8-mm mini-implants, followed by the 6-mm and 10-mm mini-implants. CONCLUSIONS: Modifying the mini-implant surface with sandblasting and acid treatment offers good bone anchoring for orthodontic purposes.

Reinforced Concrete Structure Performance in Marine Structures: Analyzing Durability Indexes to Obtain More Accurate Corrosion Initiation Time Predictions.

This paper presents a comparison of six index properties collected during durability inspections of five Mexican seaports. Typical durability indicators such as compressive strength, saturated electrical resistivity, ultrasonic pulse velocity, percent total void content, capillary porosity, and chloride concentration profiles were analyzed to obtain empirical correlations with the non-steady-state chloride diffusion coefficient. These indices were compared to determine correlation coefficients that are the most important for obtaining better corrosion initiation forecasting. Two models of corrosion initiation time (ti) were used: Fick's second law of diffusion and the reported UNE-83994-2 (Spanish Association for Standardization, UNE) in which electrical resistivity was used to calculate concrete service life. The data from both models were cleaned using correlated variables, and the initial variables were compared with ti. The main result achieved was the verification of the feasibility of using correlations of variables to clean unnecessary data in order to calculate ti. Additionally, electrical resistivity was identified as one of the main durability indexes for in-service concrete structures exposed to marine environments. This is important because electrical resistivity is a non-destructive and reliable test that can be measured both in the laboratory and in the field very easily.

Asphalt Mixes Processed with Recycled Concrete Aggregate (RCA) as Partial Replacement of the Natural Aggregate.

Materials play a fundamental role in any branch of civil engineering. From ancient times to the present day, society has required enormous amounts of construction materials, which implies an excessive exploitation of the natural environment. The present research work consisted in the design and development of asphalt mixes with a partial substitution of the natural aggregate (NA) by means of recycled concrete aggregate (RCA). The mix was designed with the Marshall methodology, considering the next percentages of substitution and addition by mass: 90% NA and 10% RCA; 80% NA and 20% RCA; 70% NA and 30% RCA. The mixtures were elaborated and analysed under the international standards and the Mexican regulation of the Communications and Transport Ministry, to determine the best option regarding their performance. The materials were characterized according to the current regulations and later employed in the mixes design. A total of 38 specimens were elaborated for each mixture, determining the optimum asphalt content; after that, mechanical tests were performed to analyse and determine the best results. In the aftermath of the examination of all mixtures, we concluded that the 70%AN/30%RCA is the best alternative option according to its performance and numeric results, complying with the cited regulations, and allowing a lower content of asphalt during the process.

RT-qPCR Assays for Rapid Detection of the N501Y, 69-70del, K417N, and E484K SARS-CoV-2 Mutations: A Screening Strategy to Identify Variants With Clinical Impact.

Background: Several variants of the SARS-CoV-2 have been documented globally during the current COVID-19 pandemic. The N501Y, 69-70del, K417N, and E484K SARS-CoV-2 mutations have been documented among the most relevant due to their potential pathogenic biological effects. This study aimed to design, validate, and propose a fast real-time RT-qPCR assay to detect SARS-CoV-2 mutations with possible clinical and epidemiological relevance in the Mexican population. Methods: Targeting spike (S) gene mutations of SARS-CoV-2 (N501Y, 69-70del, K417N, and E484K), specific primers, and probes for three specific quantitative reverse transcription PCR (RT-qPCR) assays were designed, and validated using Sanger sequencing. These assays were applied in clinical samples of 1060 COVID-19 patients from Jalisco Mexico. Results: In silico analyzes showed high specificity of the three assays. Amplicons of samples were confirmed through sequencing. The screening of samples of COVID-19 patients allowed the identification of the E484K mutation in nine individuals and the identification of P.2 Brazilian variant in Mexico. Conclusion: This work provides low-cost RT-qPCR assays for rapid screening and molecular surveillance of mutations with potential clinical impact. This strategy allowed the detection of E484K mutation and P.2 variant for the first time in samples from the Mexican population.

Effect of the Addition of Agribusiness and Industrial Wastes as a Partial Substitution of Portland Cement for the Carbonation of Mortars.

The present research work shows the effect on the carbonation of Portland cement-based mortars (PC) with the addition of green materials, specifically residues from two groups: agricultural and industrial wastes, and minerals and fibres. These materials have the purpose of helping with the waste disposal, recycling, and improving the durability of concrete structures. The specimens used for the research were elaborated with CPC 30R RS, according to the Mexican standard NMX-C-414, which is equivalent to the international ASTM C150. The aggregates were taken from the rivers Lerma and Huajumbaro, in the State of Michoacan, Mexico, and the water/cement relation was 1:1 in weight. The carbonation analyses were performed with cylinder specimens in an accelerated carbonation test chamber with conditions of 65 +/- 5% of humidity and 25 +/- 2 °C temperature. The results showed that depending on the PC substitutions, the carbonation front advance of the specimens can increase or decrease. It is highlighted that the charcoal ashes, blast-furnace slags, and natural perlite helped to reduce the carbonation advance compared to the control samples, consequently, they contributed to the durability of concrete structures. Conversely, the sugarcane bagasse ash, brick manufacturing ash, bottom ash, coal, expanded perlite, metakaolin, and opuntia ficus-indica dehydrated fibres additions increased the velocity of carbonation front, helping with the sequestration of greenhouse gases, such as CO2, and reducing environmental pollution.

Phylogenomics and population genomics of SARS-CoV-2 in Mexico during the pre-vaccination stage reveals variants of interest B.1.1.28.4 and B.1.1.222 or B.1.1.519 and the nucleocapsid mutation S194L associated with symptoms.

Understanding the evolution of the SARS-CoV-2 virus in various regions of the world during the Covid-19 pandemic is essential to help mitigate the effects of this devastating disease. We describe the phylogenomic and population genetic patterns of the virus in Mexico during the pre-vaccination stage, including asymptomatic carriers. A real-time quantitative PCR screening and phylogenomic reconstructions directed at sequence/structure analysis of the spike glycoprotein revealed mutation of concern E484K in genomes from central Mexico, in addition to the nationwide prevalence of the imported variant 20C/S:452R (B.1.427/9). Overall, the detected variants in Mexico show spike protein mutations in the N-terminal domain (i.e. R190M), in the receptor-binding motif (i.e. T478K, E484K), within the S1-S2 subdomains (i.e. P681R/H, T732A), and at the basis of the protein, V1176F, raising concerns about the lack of phenotypic and clinical data available for the variants of interest we postulate: 20B/478K.V1 (B.1.1.222 or B.1.1.519) and 20B/P.4 (B.1.1.28.4). Moreover, the population patterns of single nucleotide variants from symptomatic and asymptomatic carriers obtained with a self-sampling scheme confirmed the presence of several fixed variants, and differences in allelic frequencies among localities. We identified the mutation N:S194L of the nucleocapsid protein associated with symptomatic patients. Phylogenetically, this mutation is frequent in Mexican sub-clades. Our results highlight the dual and complementary role of spike and nucleocapsid proteins in adaptive evolution of SARS-CoV-2 to their hosts and provide a baseline for specific follow-up of mutations of concern during the vaccination stage.

Production of microbial secondary metabolites: regulation by the carbon source.

Microbial secondary metabolites are low molecular mass products, not essential for growth of the producing cultures, but very important for human health. They include antibiotics, antitumor agents, cholesterol-lowering drugs, and others. They have unusual structures and are usually formed during the late growth phase of the producing microorganisms. Its synthesis can be influenced greatly by manipulating the type and concentration of the nutrients formulating the culture media. Among these nutrients, the effect of the carbon sources has been the subject of continuous studies for both, industry and research groups. Different mechanisms have been described in bacteria and fungi to explain the negative carbon catabolite effects on secondary metabolite production. Their knowledge and manipulation have been useful either for setting fermentation conditions or for strain improvement. During the last years, important advances have been reported on these mechanisms at the biochemical and molecular levels. The aim of the present review is to describe these advances, giving special emphasis to those reported for the genus Streptomyces.

Late Frontal Negativity Discriminates Outcomes and Intentions in Trust-Repayment Behavior.

Altruism (a costly action that benefits others) and reciprocity (the repayment of acts in kind) differ in that the former expresses preferences about the outcome of a social interaction, whereas the latter requires, in addition, ascribing intentions to others. Interestingly, an individual's behavior and neurophysiological activity under outcome- versus intention-based interactions has not been compared directly using different endowments in the same subject and during the same session. Here, we used a mixed version of the Dictator and the Investment games, together with electroencephalography, to uncover a subject's behavior and brain activity when challenged with endowments of different sizes in contexts that call for an altruistic (outcome-based) versus a reciprocal (intention-based) response. We found that subjects displayed positive or negative reciprocity (reciprocal responses greater or smaller than that for altruism, respectively) depending on the amount of trust they received. Furthermore, a subject's late frontal negativity differed between conditions, predicting responses to trust in intentions-based trials. Finally, brain regions related with mentalizing and cognitive control were the cortical sources of this activity. Thus, our work disentangles the behavioral components present in the repayment of trust, and sheds light on the neural activity underlying the integration of outcomes and perceived intentions in human economic interactions.