Sudden Reduction Research Articles

Research on aging mechanism and capacity attenuation of automotive lithium-ion batteries

In order to investigate the internal mechanism and the variation law of capacity attenuation of LIBs, a simplified electrochemical model of the LIBs was established using the nickel-cobalt-aluminum LIBs as the research object, and the aging model of solid electrolyte interface SEI growth and lithium evolution was added to simulate the electrochemical behavior of the batteries. The results showed that the porosity of the anode/diaphragm reduced continually at the start of the cycle, while the SEI film grew continuously. The loss of active materials accelerated as the number of cycles increased, while the side reaction of lithium development continued. Finally, the aging mechanism was confirmed by using microscopic morphology. The results show that the negative particles are obviously crushed and contain white deposited substances. The formation of these compounds increases the oxygen content, reduces the carbon content, reduces the porosity of the electrode, increases the overpotential of the electrolyte transport, and becomes the main reason for the attenuation of the battery life. Finally, the positive particles expand and break, which leads to the sudden reduction of the battery capacity. This study determined the evolution process of aging mechanism in the whole life cycle, and provided a theoretical basis for the establishment of mechanism aging model.

Health-related quality of life predicts prognosis in individuals with COPD hospitalized with community-acquired pneumonia – a prospective cohort study

Community-acquired pneumonia (CAP) in chronic obstructive pulmonary disease (COPD) often result in sudden and persistent reduction in health-related quality of life (HRQoL), which may be alleviated with palliative care. Among individuals with COPD, we aimed to investigate potential associations between HRQoL at admission with CAP and the risk of re-hospitalization and mortality and potential associations between specific HRQoL domains and CAP treatment outcomes. HRQoL was assessed at admission and the participants were grouped into tertiles based on the HRQoL utility index and specific domains. The results revealed that participants in the middle and highest tertiles of HRQoL had a lower 90-day re-hospitalization risk compared to those in the lowest tertile, whereas no differences in re-hospitalization risk were observed 30 and 180 days after discharge. Almost one in four had severe pain or discomfort at admission and the domain pain or discomfort emerged as a predictor of re-hospitalization. In addition, participants in the middle and highest tertiles had lower risk of 180-day mortality compared to those in the lowest, while no differences were observed in 30-day or 90-day mortality risk. An increased focus on in-hospital palliative care could alleviate the pain and discomfort reported by many participants with potential to reduce re-hospitalization rates.

Akutní poškození ledvin u kriticky nemocných a střevní dysmikrobie

Introduction: Acute kidney injury (AKI) occurs in critically ill patients with significant impact on their morbidity and mortality. The sudden reduction in renal function affects the function of other organs, comprising the intestine, inducing intestinal dysmicrobia, which reciprocally worsens the course of AKI and may also lead to the development of chronic nephropathy. Purpose: Pathophysiology of AKI, sepsis and intestinal dysmicrobia in a critical patient with impact on the development of the disease and other organ systems with possibilities of its positive influence by nutritional measures. Conclusion: Critically ill patients especially in septic status complicated by AKI are prone to complications such as intestinal dysmicrobia, secondary sepsis and immunodeficiency. Treatment of the underlying disease and its complications along with nutritional support helps to improve the clinical outcome of this group of patients.

Assessing universal considerations in infant mortality across the globe: A descriptive observational study of sudden infant death syndrome knowledge and reduction coverage on YouTube.

Sudden unexpected infant death (SUID) remains one of the leading causes of infant mortality worldwide and is largely driven by sudden infant death syndrome (SIDS). Although SIDS has received coverage and examination of content spanning Instagram, Facebook, and Twitter across the published academic literature, there is no study to date that has examined SIDS related content on YouTube. This descriptive observational study was conducted from December 2023 through January 2024 and sought to describe the sources, formats and content covered across the 100 widely viewed videos pertaining to SIDS on YouTube. The majority of the videos published were by organizations (N=64) including healthcare systems, the American Academy of Pediatrics (AAP) and police departments. Several of the widely viewed SIDS-related content was disseminated by professionals (N=42). Multiple videos presented content on the symptomology pertaining to SIDS as well as contributing environmental risk factors. A wide range of resources were depicted as SIDS reduction measures. Notably, there was substantial emphasis on SIDS reduction postnatally across the widely viewed videos. There was limited representation of content on SIDS awareness and reduction outside of the United States. Clinical, public health, and organizational implications and recommendations are presented to inform future targets for intervention that can harness findings from this study on widely covered and uncovered content to address the totality of risk factors for SIDS. Future directions in health promotion across the SIDS reduction landscape are also reviewed to account for digital spaces globally, thereby contributing towards reducing infant mortality worldwide.

Adherence to anti-hypertensive therapy with perindopril-based single-pill versus free-pill combinations: a 10-year real-world analysis in Italy

Abstract Background/Introduction Despite the growing availability of blood pressure-lowering drugs, hypertension remains poorly controlled and a significant mortality cause worldwide. The silent course of the disease, suboptimal adherence, and complexity of therapeutic schedules are important factors in reducing the effectiveness of anti-hypertensive treatments at the population level. With the purpose of simplifying patients’ medication self-management, guidelines have strongly endorsed the use of anti-hypertensive therapy with single-pill combinations (SPCs). Perindopril (PER)-based SPCs, including both two- and three-drug combinations, have been available since 2008. Purpose We explored treatment adherence over 10 years in patients receiving PER-based regimens (SPC or free-pill combination) in Italy. Methods A retrospective real-world analysis was conducted on administrative databases covering 6.7 million Italian health-assisted residents. Among adults with hospitalization discharge diagnosis or exemption code for hypertension between 2010 and 2021, those with PER-based prescriptions were identified, considering combinations with amlodipine (AML) and/or indapamide (IND), either as SPC or free-pill or mixed (SPC+separate pill). The index-date (ID) was that of the first prescription of a PER-based regimen throughout the inclusion period. All patients with at least 12 months of available data before and after the ID were included. A cross-sectional analysis evaluated the yearly adherence for the period 2012-2021, calculating the proportion of days covered (PDC) by drug prescriptions on 1-year follow-up (PDC≥80% indicated high-adherence). Results Over 2012-2021, of 121,397 patients on a PER-based therapy, those treated with SPC ranged from 87% (during 2012) to 94.4% (during 2021), while free-pill and SPC+separate pill cohorts represented, respectively, 10.6-3.5% and 2.4-2.1% of all hypertensive patients. Over the decade, the proportion of adherent patients in SPC users was markedly higher than in free-pill and SPC+separate pill cohorts (Fig. 1). The sudden reduction of adherent patients during 2018-2019 was possibly due to a temporary shortage of PER/AML/IND as SPC in Italy from Nov-2018 to Mar-2019. Multivariate analysis showed that over 2012-2021 decade, free-pill and SPC+separate pill regimens resulted in significantly lower adherence (more than 80% reduction) than SPC formulation, while male gender and older age were predictive of better adherence (Table 1). Conclusions These findings from real clinical practice in Italy highlighted a growing attitude from clinicians to prescribe more manageable anti-hypertensive schemes based on SPC formulations, in line with current guidelines. The higher proportion of adherent patients among the users of PER-based SPCs corroborates the importance of alleviating pill burden, that is a key component in blood pressure control, and so in the reduction of hypertensive complications and cardiovascular risk.

Passive control and damage assessment with a pendulum tuned mass damper using mean square equations and second-order eigen-perturbation techniques

This paper proposes a novel framework for damage detection and retuning of a Pendulum Tuned Mass Damper (PTMD) addressing effects of stochasticity via mean-square equations and establishing rapid change detection. The framework was made possible via a Stochastic Differential Equation (SDE) formulation of the equations of motion considering a two degree of freedom base and structure system equipped with a PTMD. The system was assumed to be excited at the base with Gaussian white noise and the solutions were computed using a stochastic integration scheme. A Second Order Eigen-Perturbation (SOPS) estimate is used to carry out detection of sudden stiffness reduction in the base floor of the structure. Once damage is detected, mean square equations on monitored displacements were used to retune the PTMD by adapting the length of the pendulum. It was found that damage could be detected rapidly and successive retunings were able to minimize the mean square displacement of the damaged structure and stabilise it over time.

Housing prices, airport noise and an unforeseeable event of silence

To evaluate the causal impact of noise exposure on housing prices, we exploit a sudden and massive reduction in flight traffic that occurred with the onset of the COVID-19 measures in Germany. Comparing locations differently exposed to pre- pandemic noise with a difference-in-difference approach, we detect a 2.4% increase in prices for apartments that experienced a noise reduction. Disentangling temporal dynamics, we find a peak effect in mid-2021 (up to 6%), with the effect persisting until 2023, albeit at a lower magnitude. In contrast to most evaluations showing that the erection of a disamenity affects prices negatively, we show that lifting the burden enables neighborhoods to catch up again immediately. The immediate catch-up contradicts a stickiness of housing prices regarding (temporal) local factors. The temporal pattern shows a clear peak of the effects during the pandemic, which potentially hints at information asymmetries since buyers may not know the non-pandemic noise level during the pandemic.

Economic impacts of a drastic gas supply shock and short-term mitigation strategies

The Russian invasion of Ukraine on February 24, 2022 entailed the threat of a drastic and sudden reduction of natural gas supply to the European Union. This paper presents a techno-economic analysis of the consequences of a sudden gas supply shock to Austria, one of the most dependent countries on imports of Russian gas. Our analysis comprises (a) a detailed assessment of supply and demand side countermeasures to mitigate the immediate shortfall in Russian gas imports, (b) a mapping of the net reduction in gas supply to industrial sectors to quantify direct economic shocks and expected relative reductions in gross output and (c) the quantification of higher-order economic impacts through using a dynamic out-of-equilibrium input–output model. Our results show that potential economic consequences can range from relatively mild to highly severe, depending on the implementation and success of counteracting mitigation measures. We find that securing alternative gas imports, storage management, and incentivizing fuel switching represent the most important short-term policy levers to mitigate the adverse impacts of a sudden import stop.

Impact of Sudden Infant Death Syndrome Risk Reduction Guidelines on Mothers' Knowledge and Practices and their Infants' Outcome

Impact of Sudden Infant Death Syndrome Risk Reduction Guidelines on Mothers' Knowledge and Practices and their Infants' Outcome

Molecular Insight into Acute Limb Ischemia.

Acute limb ischemia (ALI) is defined as a sudden reduction in blood flow to a limb, resulting in cessation of blood flow and, therefore, cessation of the delivery of nutrients and oxygen to the tissues of the lower limb. Despite optimal treatment to restore blood flow to ischemic tissues, some patients may suffer from ischemia/reperfusion (I/R) syndrome, the most severe complication after a revascularization procedure used to restore blood flow. There are multiple molecular and cellular factors that are involved in each phase of ALI. This review focuses firstly on molecular and cellular factors of arterial thrombosis, highlighting the role of atherosclerotic plaques, smooth muscle cells (SMCs), and cytokine which may alter key components of the extracellular matrix (ECM). Then, molecular and cellular factors of arterial embolism will be discussed, highlighting the importance of thrombi composition. Molecular and cellular factors of ischemia/reperfusion syndrome are analyzed in depth, highlighting several important mechanisms related to tissue damage, such as inflammation, apoptosis, autophagy, necrosis, and necroptosis. Furthermore, local and general complications of ALI are discussed in the context of molecular alterations. Ultimately, the role of novel biomarkers and targeted therapies is discussed.

The association between COVID-19 related income loss and diet quality: The mediating role of distress

The COVID-19 lockdowns saw many individuals lose income, experience distress and increase intake of foods that would typically be considered less ‘healthy’ (more processed and less fresh produce). Establishing whether there are direct and indirect links between these variables would be of benefit in preparing for similar future events but also has implications for the current global financial climate, where many are experiencing relative decreases in income. Adults in two locations (UK and Australia) (N = 917) completed online questionnaires to explore the impact of the first COVID-19 lockdown on their change in income, emotional wellbeing (depression, anxiety, stress, loneliness), resilience and diet quality. A structural equation model revealed that income loss was indirectly associated with diet quality via distress. As such, the greater the loss of income experienced, the more distress reported; distress was then directly associated with a less nutritious diet. This pattern of results existed when data from both countries were combined but also when they were modelled individually. Our findings indicate that where individuals experience a sudden reduction of income there are likely to be negative consequences for both mental and physical health. It is plausible that these findings would extend to other circumstances in which sudden loss of income may be experienced such as reductions in state social care, rising inflation and interest rates and sudden increases to the general cost of living.

Water transport in double-walled carbon nanotubes

Water confined in nanoscale environments exhibits rich phase behaviors. Recently, double-walled carbon nanotubes (DWCNTs) have been found to be able to generate ice nanotubes with large sizes, but their dynamics are still not explored. In this work, upon using molecular dynamics simulations we systematically investigate the water transport in DWCNTs, focusing on the effect of CNT length and temperature. At low temperatures, with the increase in CNT length, the water flow decreases linearly first and then has a sudden reduction to zero because of the liquid-ice phase transition; while at high temperatures the water flow decreases linearly without freezing. Obviously, the critical CNT length for the formation of ice increases at higher temperatures, because longer CNTs facilitate the ordered water structures. Furthermore, for a short CNT the water flow exhibits a perfect linear increase with the temperature; while for long CNTs, the water flow is zero at low temperatures because of the ice phase, and then increases suddenly. Apparently, the critical melting temperature shifts to higher values for longer CNTs. The translocation time has an overall opposite behavior compared to the water flow, and the water occupancy and dipole orientation are also sensitive to the CNT length and temperature. Our results reveal the relationship between water structures and dynamics within DWCNTs, and should have great implications for the design of novel nanofluidic devices.

Vertical pay disparity, traditional Chinese culture, and employee productivity

We examine how traditional Chinese culture interplays with pay disparity to affect employee productivity. In particular, we leverage an exogenous regulatory reform in Chinese state-owned enterprises (SOEs) to reduce vertical pay disparity (i.e., the difference between executive and average employee pay within a firm). Our results show that in a cultural context characterized by high levels of power distance and masculinity, a sudden reduction in vertical pay disparity is accompanied by a notable decline in employee productivity. Furthermore, the decline in productivity is more pronounced when employees are exposed to greater cultural traditionality. We also show that executive compensation declines after the Reform while employee pay stays unchanged. Importantly, our additional results show that neither managerial efficiency nor the departure of high-performing executives changed significantly after the Reform, and the performance effects of pay disparity are not primarily attributable to economic incentives for SOE executives or employees. Overall, our findings suggest that imposing pay restrictions without taking cultural context into account can have adverse effects on firm performance.

CARDIOGENIC SHOCK IN A PATIENT WITH SEVERE AORTIC VALVE STENOSIS AND MULTIVESSEL CORONARY DISEASE: ADVANCED THERAPEUTIC STRATEGIES

Abstract We describe a case of a 58 years old man. He was referred to emergency room for episodes of vomiting and epigastric pain for about a week. Upon admission he was confused with systolic–diastolic blood pressure values ​​70/40 mmHg, heart rate 120 bpm, sinus rhythm. pO2 was 80 mmHg and SO2 in air 97%. Lactate values 10, blood sugar > 300 mg/dl. The electrocardiogram showed sinus tachycardia with the results of antero–septal necrosis and incomplete left bundle branch block. The fast echocardiogram showed a dilated left ventricle with severe depression of the ejection fraction (EF about 10–15%), severe low flow–low gradient aortic valve stenosis (AVA bidimensional was approximately 0.9 cm²), severe mitral valve insufficiency due to a dual mechanism. The dimension of Inferior vena cava was 1.5 cm, collapsible. There was thrombotic stratification in the apex of the left ventricle and VA coupling was 2. The patient was admitted to the ICU with stage C cardiogenic shock according to SCAI classification. We found a value of PVC 3 mmHg. After fluide challenge there was an increase in blood pressure values to 100/60 mmHg. Noradrenaline vasopressor was started and subsequently a low dose of adrenaline. Blood pressure values maintained around 90/60 mmHg and undergo a sudden drop after increasing the dosage of the vasopressor. Diuresis was approximately 50 ml/h, lactates clear completely after approximately 4 hours. After 6 hours, due to a new sudden reduction in blood pressure, the patient was referred for IABP and coronary angiography control. In the context of multivessel coronary artery disease and cardiogenic shock he was therefore a candidate for urgent cardiac surgery of aortic valve replacement, by–pass and mitral anulovalvuloplasty. This case gave us the opportunity to analyze how to proceed in such a critical conditions with the below conclusions: a) the choice of vasopressors and inotropes is limited in case of severe aortic valve stenosis b) the presence of left ventricular intracavitary thrombosis limits the choice of ventricular assistance system c) in case of cardiogenic shock and severe aortic valve stenosis the patient must be a candidate for valve replacement surgery as soon as possible.

On the temperature dependence of enzymatic degradation of poly(ethylene terephthalate)

Enzymatic recycling of poly(ethylene terephthalate), PET, has attracted significant attention in recent years. Temperature is a governing factor in the enzymatic degradation of PET, influencing simultaneously the catalytic activity and thermal stability of enzymes, as well as the biodegradability of PET materials from many perspectives. Here we present a detailed examination of the complex and mutual effects of temperature on the degradation of low-crystallinity PET (LC-PET, 7.6%) and high-crystallinity PET (HC-PET, 30%) microparticles using the WCCG variant of the leaf-branch compost cutinase (LCC). The degradation velocity apparently increases exponentially with increasing temperature at temperatures below 65 °C. Arrhenius plots show a sudden reduction in activation energy at temperatures higher than 40 °C, suggesting the onset of the surface glass transition of PET particles. This is more than 20 °C lower than the bulk glass transition temperature, underscoring the interfacial catalytic nature of enzymatic PET degradation. WCCG undergoes substantial conformational changes upon thermal incubation at temperatures ranging from 50 to 70 °C and exhibits enhanced activity, owing to the increased intrinsic catalytic activity and improved adsorption on PET surface. Further increasing the temperature leads to the inactivation of enzymes alongside the rapid recrystallization of amorphous PET, impeding the enzymatic degradation. These findings offer a detailed mechanistic understanding of the temperature dependence of the enzymatic degradation of PET, and may have implications for the engineering of more powerful PET hydrolases and the selection of favorable conditions for industrially-related recycling processes.

Entanglement of edge modes in (very) strongly correlated topological insulators

Identifying topological phases for a strongly correlated theory remains a non-trivial task, as defining order parameters, such as Berry phases, is not straightforward. Quantum information theory is capable of identifying topological phases for a theory that exhibits quantum phase transition with a suitable definition of order parameters that are related to different entanglement measures for the system. In this work, we study entanglement entropy for a coupled SSH model, both in the presence and absence of Hubbard interaction and at varying interaction strengths. For the free theory, edge entanglement acts as an order parameter, which is supported by analytic calculations and numerical (DMRG) studies. We calculate the symmetry-resolved entanglement and demonstrate the equipartition of entanglement for this model which itself acts as an order parameter when calculated for the edge modes. As the DMRG calculation allows one to go beyond the free theory, we study the entanglement structure of the edge modes in the presence of on-site Hubbard interaction for the same model. A sudden reduction of edge entanglement is obtained as interaction is switched on. The explanation for this lies in the change in the size of the degenerate subspaces in the presence and absence of interaction. We also study the signature of entanglement when the interaction strength becomes extremely strong and demonstrate that the edge entanglement remains protected. In this limit, the energy eigenstates essentially become a tensor product state, implying zero entanglement. However, a remnant entropy survives in the non-trivial topological phase, which is exactly due to the entanglement of the edge modes.

The industrial SO2-induced corrosion: Investigation of the corrosion onset

The stability of the passivation film on reinforcing steel is significantly influenced by the internal chemical environment of concrete under industrial sulfur dioxide (SO2) corrosion. This study aimed to investigate the electrochemical state of the reinforcing steel and the internal chemical environment (corrosion products, phase composition, and pore structure) of concrete by conducting indoor simulations of reinforced concrete specimens exposed to industrial SO2 environment. The results indicated a consistent trend in open circuit potential (OCP) and corrosion current density (icorr) of steel rebar in different types of concrete. A sudden reduction in OCP is accompanied by a significant increase in icorr when the rebars reach an active state. At this time, the ratio of sulphation depth to protective layer thickness ranges from 0.47 to 0.63. The main sulphation products were gypsum and ettringite, with their content decreasing as the cover layer depth, water-to-binder ratio, and fly ash content increased. Due to crystallization pressure and expansion, the impact of SO2 corrosion on the capillary pores of concrete was the most significant, followed by its effect on larger pores. After 96 days of corrosion, there was an increase of 191.7 % and 116.2 % in the quantity of pore sizes, respectively. Furthermore, the porosity growth rate in concrete with the incorporation of fly ash is lower than that of Portland concrete. This suggests that the rational use of fly ash to partially replace Portland cement is beneficial for enhancing the resistance of concrete to SO2 corrosion.

Experimental axial-compressive behaviour of bare cold-formed-steel studs with semirigid-track and ideal-hinged boundary-conditions

Studs are the primary load-bearing components in cold-formed steel (CFS) wall panels, connected to tracks at both ends with self-tapping screws, forming a semirigid boundary condition (BCT). Most existing tests on the axial compressive behaviour of bare CFS studs are based on either theoretically-hinged (BCH) or fully-fixed boundary conditions. Previous researchers have employed BCT only on sheathed stud-wall panels. However, practicing engineers and current design codes, e.g., Eurocode 3, follow an all-steel design. Therefore, this research experimentally investigated bare-CFS-studs' axial compressive behaviour with BCT, considering, for the first time, the combined effect of the tracks' warping rigidity, stud-to-track gap, non-linear connection stiffness, and bare studs' various cross-sectional slenderness. Forty-two industry-standard lipped channel sections (studs) of five thicknesses (1.2-3 mm), three depths (75–125 mm), and two heights (1.2 & 1.5 m) were tested under static-concentric axial compressive loading with BCT. Another fourteen studs were tested with BCH, a comparator to BCT. Results demonstrated that the studs' global failure mechanisms were flexural-torsional in BCT instead of flexural in BCH. Studs' axial stiffness was two-phased in BCT due to the stud-to-track gap, compared to single-phased stiffness in BCH. >1.8 mm stud-to-track gap caused stud-to-track connections' failure and studs' sudden capacity reduction during gap closure. Studs achieved 1.22 times higher axial-compressive strength, 2.3 times more axial-shortening, 0.7 times lower axial stiffness, and 58% lower axial-compressive strain at the web-midheight under BCT-PhaseII than BCH. Tested strengths were compared with EC3 design strength, and an effective-length-factor of 0.65 was suggested for efficient design of studs with BCT.

Exposure of firefighters to carbon monoxide during rescue and fire fighting interventions - a 6-year analysis

Exposure to carbon monoxide is a common hazard in firefighting practice throughout the year, regardless of the winter heating season. Therefore this analysis of the interventions of fire protection units in incidents related to carbon monoxide exposure of a non-fire origin. The objectives include two risk groups: people affected by the intervention and the health risks to fire officers themselves.The analysed material covers the years 2017-2022 and interventions of fire protection units in incidents related to carbon monoxide exposure of a non-fire origin (chemical hazard events). Data from the Decision Support System of the State Fire Service (DSSSFS), provided to the authors by the Operational Planning Office at the Headquarters of the State Fire Service, were used in the study.According to the records of the State Fire Service (SFS) in the years 2017-2022, there were 28,766 (Mean 4794; SD 413) chemical hazard events: carbon monoxide was the cause. There were only 5724 reports of symptoms with a known CO concentration and 1974 reports with clinical symptoms. Statistically significant differences were demonstrated in exposure time (p= 0.028) and average CO concentration in the analysed years (p<0.001). Noteworthy is the sudden reduction in the exposure time following the year 2020.The actual exposure of firefighters to carbonmonoxide is greater than in the above analysis, in addition, there are exposures from fire incidents. Procedures, measuring equipment, and personal protective equipment protect firefighters from absorbing harmful substances into the body, but the large number of incidents and the visible clinical symptoms in victims should prompt firefighters with many years of service to observe even the smallest worrying neurological changes in themselves.

Hematological, biochemical and oxidative responses induced by thermal shock in juvenile Tambaqui (Colossoma macropomum) and its hybrid Tambatinga (Colossoma macropomum x Piaractus brachypomus).

The effects of thermal shock on hematological, biochemical and antioxidant responses were evaluated in liver tissue of juvenile tambaqui (Colossoma macropomum) and tambatinga (♀ C. macropomum × ♂ Piaractus brachypomus). Forty juveniles of tambaqui and 40 juveniles of tambatinga, of the same age and with an initial weight of 23.3 ± 6.7g, were randomly distributed in eight 28L circular tanks. A tank (n = 10 fish) of tambaqui and a tank (n = 10 fish) of tambatinga were then used to obtain basal data. The other animals were subjected to thermal shock with sudden temperature reduction from 28 to 18 ºC. Blood and tissue were then collected after 1, 6 and 24h from the onset of thermal shock. No mortality was observed during the experimental period. Thermal shock increased triglyceride levels after 24h of stress for tambaqui and reduced values for tambatinga. There was an effect on plasma glucose only for fish group (P < 0.0001) and collection time (P < 0.0001) with a peak observed for the hybrid after 6h. The interaction of factors for SOD indicated greater activity for tambatinga at the 6h collection and lower at basal and 1h collections. There was an interaction for CAT (P = 0.0020) with less activity for tambatinga at 1h. However, thermal shock and hybridization did not influence GST and TBARS levels in liver tissue. Therefore, the results suggest that the hybrid, tambatinga, is more efficient at promoting adjustments of biochemical responses and antioxidant enzymes during thermal shock.