Academic dishonesty is becoming a big concern for the education systems worldwide. Despite much research on the factors associated with academic dishonesty and the methods to alleviate it, it remains a common problem at the university level. In the current study, we conducted a survey to link personality traits (using the HEXACO model) and people’s general attitudes towards the rule  to academic dishonesty among 370 university students. Using correlational analysis and structural equation modeling, the results indicated that both personality traits and attitudes towards the rule significantly predicted academic misconduct. The findings have important implications for researchers and university educators in dealing with academic misconduct. It is considered immoral and inappropriate because the behavior has an unfair advantage over other students and impedes individuals’ capacity to study3. Dishonesty behavior often starts early in school, such as copying others’ work, and has been a consistent and paramount problem throughout all education levels4. It is an educational and academic issue with severe consequences5. Engagement in academic dishonesty predicts increased acceptance of immoral workplace behavior, indicating its continuous influence post-graduation7. At the university level, such misconduct behavior has clear potential to diminish the reputation and integrity of universities. It hinders universities’ ability to ensure that students who achieve degrees have the knowledge and skills they require for employment or further study8.Academic dishonesty is a global issue that attracts much attention from educators worldwide, and relevant research could date back to the last century9. Several personality traits were found to be significantly predictive, such as impulsivity10, psychopathy11, Machiavellianism and narcissism12. Self-control may explain why people do, or do not, engage in plagiarism when the opportunity is available13. Curtis et al.14 found that self-control and academic misconduct were negatively correlated. Although individuals’ self-control can vary depending on situational factors such as mood, fatigue, and hunger, it is more like stable personality-like differences15.Much literature on the individual predictors of academic cheating has mostly focused on the influences of personality traits, academic attitudes & values, and some demographic variables16. However, age and gender are not consistently found to be significant factors in most research on academic misconduct17.Research on the demographic variables found that age and gender are critical factors predicting academic misconduct. For instance, as they age, female college students are less likely to engage in academic dishonesty due to fewer comparisons between one’s own behaviors and peer behaviorsIn the current study, we still focused on these individual factors with attempts to 1) assess a recent model of personality  and its predictive power of academic dishonesty; and 2) to link people’s general attitude towards the rule/law to academic dishonesty, considering that it is essentially a violation of the rules in academia. Age and gender effects are examined along with the above goals.18 considered academic dishonesty to contain four main types of misconduct that deliberately violate school regulations: cheating, fabrication, facilitation, and plagiarism. McCabe and Trevino19 further expanded the scope of this concept into 12 types of violating behaviors in school, including sneaking at notes in the exam, copying others’ answers in the exam, copying others’ answers without their permission in the exam, etc. These researchers developed a 12-item scale to measure academic dishonesty, which is widely used20. However, Adesile and Nordin21 criticized that the psychometric properties have not been critically investigated despite their broader literature application. To validate the psychometric properties of the instrument and determine the dimensionality of academic dishonesty, Adesile21 adapted the original scale, divided academic dishonesty into three dimensions , and named it “the academic integrity survey.”Academic dishonesty, academic misconduct, academic cheating, and academic integrity are concepts often used interchangeably in previous literature. The concept is usually defined through behavioral classifications. Pavela22. Motivation is one of the major individual factors relating to academic dishonesty. Through a meta-analytic investigation, Krou and colleagues23 reviewed 79 studies and reported that academic dishonesty was negatively associated with intrinsic motivation, self-efficacy, utility value, and internal locus of control, and was positively associated with amotivation and extrinsic goal orientation. Motivation, however, may vary across different cultural backgrounds. A recent study of Chinese university students found that their unethical academic behaviors are associated with their unique motivation to meet parents’ expectations24.Academic dishonesty is found to be largely explained by individual factors27. Meanwhile, moral disengagement is positively associated with cheating28. The predicting effect of morality may also be inconsistent across cultures. Ampuni et al.29 studied the relationship between academic dishonesty and the five moral foundations in Indonesia, and found only a weak predictive power of the “authority” foundation on academic dishonesty.Morality is another crucial predictor of academic cheating and plagiarism. Individuals with a high level of morality, emphasis on fairness, and value of social rules have stringent attitudes towards plagiarism30. Studies, however, provided little and even opposite evidence regarding the actual behavioral differences in academic misconduct between traditional and online settings. Peled et al.31 found that students tend to engage less in academic dishonesty behaviors online than in face-to-face courses. In addition, cheating intentions among students in traditional and online education settings are very little32. To reconcile the inconsistent findings, researchers started considering potential moderating and mediating factors such as the types of academic dishonesty, the level of technology complexity, and statistics anxiety35.Since the COVID-19 epidemic outbreak, courses and examinations have been conducted online, and researchers are concerned that academic misconduct in online learning environments has become more serious36 reviewed studies of both high school and university students, and concluded that conscientiousness and agreeableness (of the Big Five) are the strongest predictors of academic dishonesty. Graziano and Eisenberg37 found agreeable people more trusting and less cynical. As a result, they were less likely to justify cheating and see it as a necessity to compete with others. Lee et al.9 conducted a meta-analysis on predictors of academic dishonesty and confirmed the strong relationship between agreeableness and academic dishonesty. They also found openness to be associated with self-efficacy/personal ability, and in turn, was negatively related to academic dishonesty. Finally, a positive association between neuroticism and academic procrastination increased cheating behaviors at school38.Personality reflects a person’s consistent patterns of thoughts, feelings, and behaviors. It has a large effect on individuals’ academic behaviors. The Big Five personality model is the most widely used predictor of academic dishonesty. For instance, Giluk and Postlethwaite11, while others indicated a moderate negative association39, and nonsignificant findings36.Empirical evidence on the relationship between extraversion and academic dishonesty, however, is not consistent. For example, some research found a small positive association between extraversion and scholastic dishonesty40 extended the Big Five personality model with a set of lexical studies, and developed a six-dimension model, referred to as the HEXACO model of personality structure. The name of this model reflects both the number of factors  and their names: Honesty-Humility (H), Emotionality (E), extraversion (X), Agreeableness (A), Conscientiousness (C), and Openness to Experience (O). It is essential the Big Five personality plus an additional Honesty-Humility dimension. The six-dimensional structure was more replicable across cultures than the Big Five model, as the Big Five structure has failed to present in four languages that recovered the HEXACO dimensions41. It has become a major tool in measuring personality traits in the early 21st century.Ashton and Lee42 investigated the relationship between Honesty-Humility and cheating behavior. Results showed that individuals high in Honesty-Humility were less likely to cheat than those low on this trait. Honesty-Humility was negatively associated with adolescents’ unethical behavior, and moral disengagement partially mediated this negative association43. Hilbig and Zettler44 found that German adults who were low in Honesty-Humility were more likely to behave dishonestly across various experimental situations . Honesty-Humility was negatively associated with unethical business decisions among people from Fiji and the Marshall Islands45. Honesty-Humility was proved to be the strongest predictor of cheating, dishonesty, counterproductive behavior, and antisocial behavior, according to a meta-analysis41. Accordingly, the current study posits that,The HEXACO model, particularly the Honesty-Humility (H) dimension, is proven to be very useful in predicting many unethical behaviors. Kleinlogel et al.All six dimensions of the HEXACO model will predict academic dishonesty. Specifically, Honesty-Humility (H), Agreeableness (A), Conscientiousness (C), Openness to Experience (O), and Emotion Stability (E) are all expected to predict academic dishonesty negatively.46 refers to individuals’ variability in perceptions of obeying general laws. The higher the endorsement, the more likely they are to comply with laws and rules. If one’s POOL level is high, it has nothing to do with the fear of violating and thus being punished by the laws, and it is also not because someone sees other people’s compliance behaviors and tries to conform and comply. POOL exists at the personal level, which arises from people’s knowledge and conscience to stand up for the laws and rules.The concept of the perceived obligation of law/rule proposed (short for POOL) by Tyler47. In other words, if one’s POOL is higher, one is not expected to perform academic misconduct, as the person would like to obey the rule or law, and volunteer to restrain one’s behavior. POOL is also found to be a key element in predicting compliance behavior to slow the spread of the virus during the COVID-19 pandemic48.Tyler’s research has shown a negative link between POOL and general criminal behavior. The more one perceives an obligation to obey the law, the less likely one will violate the law49. In other words, less rule-oriented people accept more reasonable circumstances to break the rules, and those who are more rule-oriented acknowledge fewer acceptable circumstances to violate the regulations.Rule conditionality (RC), also called rule orientation, assess the extent to which an individual perceives it is acceptable to violate the legal rules under certain conditions49.RC derives from POOL and negatively relates to POOL, but they are very different. RC presents the level of flexibility when people evaluate different circumstances to break the law or rules. POOL is a sense of one’s obligation and duty to obey the laws and regulations. RC played a crucial role in predicting compliance behaviors and law violations. When laws go against personal morals, people will weigh the advantages, and disadvantages of immoral behavior, combined with moral belief, the lack of knowledge of the law, cost-benefit analysis, social norms, and lack of procedural justice are all critical roles in influencing the possibility of violating the law,In general, since both POOL and RC are stable personality-like variables that do not vary across mood and situations, and because misconducts in academia are rule violations by their nature , we expect that students’ perception of the duty to obey the law/rule and their sense of rule conditionality would both be significant predictors of academic dishonesty. Accordingly, the current study expects thatRC positively predicted academic dishonesty, and POOL negatively predicted academic dishonesty. That is, participants who are more likely to consider rules as conditional, will report more cheating behaviors. In contrast, participants who perceive more obligation to obey the law, will report fewer cheating behaviors.The current study has been approved by the IRB of School of Philosophy and Sociology of Jilin University. Informed consent has been obtained from all participants of the present study. All methods were performed in accordance with relevant guidelines and regulations.The sample consists of 370 students coming from a Northern Chinese University. The mean age of the participants was 19.77 years old (SD = 3.63). 224 (60.54%) participants majored in sciences and 146 (39.46%) participants majored in humanities and social sciences. 211 (57.03%) were male students, and 159 (42.97%) were female students.All research instruments were originally in English, translated into Chinese by a psychology graduate student, and back-translated by a bilingual psychology researcher.50 was used to measure academic dishonesty (α = 0.916). It contains 15 items assessing the “Cheating,” “Research Misconduct,” and “Plagiarism” of academic misconduct. The survey comprised an 8-point Likert scale . A higher score on the scale indicated a higher level of academic dishonesty. The internal consistency for the whole scale in current study was 0.955, with Cronbach’s alpha being 0.919, 0.812, and 0.817 for “Cheating,” “Research Misconduct,” and “Plagiarism,” respectively.The Academic Integrity Survey (AIS)40, a six-dimension structure containing the factors Honesty-Humility (H), Emotionality (E), Extraversion (X), Agreeableness (A), Conscientiousness (C), and Openness to Experience (O), was used as a measure of personality, with 60 items in total. The internal consistency reliabilities ranged from 0.77 to 0.80 in the college sample and from 0.73 to 0.80 in the community sample51. The HEXACO-60 comprised a 5-point Likert scale . Cronbach’s alpha was 0.795 in the current study.The HEXACO model49 was utilized to indicate the extent to which individuals perceive acceptable conditions for breaking the law in general (α = 0.928). The 7-point Likert scale  contains 12 items, which is calculated as a mean score , with higher scores indicating more rule conditionality . Cronbach’s alpha was 0.868 in the current study.Rule Conditionality Scale47 includes six items on a 4-point Likert scale . The POOL was calculated as a mean score of all items , with a higher score indicating a higher perceived obligation to obey the law. Cronbach’s alpha was 0.671 in the current study.Perceived Obligation to Obey the LawParticipants were offered course credits to take part in an online study. Wenjuanxin was used as the data collection platform, providing functions equivalent to Amazon Mechanical Turk. The participants were asked to answer the AIS, HEXACO, RC, and POOL questionnaires and then reported demographic information (gender and age). Data were excluded from the analysis if the participants failed to choose the correct answer of the “filter” items (e.g. “Please choose #1 on this question”). A total of 397 questionnaires were collected and 370 were valid (rejection rate = 6.80%).SPSS and Amos 26.0 were used for data analysis. Pearson correlation analysis and structural equation model were conducted to test the hypotheses.p < 0.01). As age increased, people were more likely to conduct various academic misconducts.Pearson correlation was used to examine the correlations among the variables. Regarding the effects of demographic variables on academic dishonesty, age was positively correlated with academic dishonesty , emotion stability , agreeableness , conscientiousness , openness to experience , and extraversion .Regarding the effects of personality traits on academic dishonesty, as expected and in line with a prior studyp < 0.01). It showed that academic misconduct was more acceptable as students scored higher on rule conditionality, consistent with the hypothesis. Contrary to the hypothesis, however, perceived obligation to obey the law/rule was not correlated with academic dishonesty . In addition, POOL was also not associated with five of six personality dimensions nor rule conditionality  52.The structural equation models linking the demographic variables (age and gender), the personality variables (HEXACO), and the attitude variables (RC and POOL) were tested. The findings were presented in Fig. In general, students’ tendency to engage in academic dishonesty was accounted for by the demographic variables, the personality variables, and the attitude variables. Specifically, consisting to the results of correlation analysis, age but not gender positively predicted academic dishonesty. The HEXACO model negatively predicted academic dishonesty, with five out of the six dimensions being significant except for the emotionality dimension. It indicated that people who scored higher on honesty-humility, agreeableness, conscientiousness, openness to experience, and extraversion were less likely to engage in academic misconduct. In addition, rule conditionality positively predicted academic dishonesty, indicating that individuals who believed in the conditionality of rules were more likely to misbehave at school. These results partially aligned with the hypotheses.41. The current study applied the HEXACO model in predicting academic dishonesty for the first time, and our findings justified its application.The purpose of this study is to explore the influence of individual factors  on academic dishonesty. A survey among university students was conducted, and the results provided evidence that both personality traits and people’s rule orientation had significant effects on their various academic misconducts. The HEXACO model is a relatively recent personality model to expand and replace the Big Five personality model, and its cross-cultural applicability has been verified in many research settings53. POOL is likely an inadequate measure of Chinese students’ sense of obligation and duty to obey the laws and rules. Future research could use a different sample to test the predicting effect of POOL on academic dishonesty, and should also consider revising and refining the POOL measure for cultural research.Attitudes towards the rule are manifested in two aspects. Rule conditionality assessed whether individuals would violate relevant regulations and commit deviant behaviors under certain circumstances. Perception of the obligation to obey the law and rules (POOL) assessed individuals’ sense of duty to avoid behaviors that violate regulations, such as academic misconduct. Results of the current study demonstrated that rule conditionality positively predicted academic misconduct; that is, individuals who believed that rules are conditional and could be broken under certain conditions are more likely to engage in various academic transgressions. POOL, however, was not found to be related to academic dishonesty. Previous results showed that Chinese students scored lower on the POOL than American students17.Regarding the predictive effect of demographic variables on academic misconduct, only age was found to have a significant positive correlation with academic misconduct. Gender had no effect which is consistent with the previous literature54. Our research findings encourage university educators and institutional policymakers to pay much attention to this dispositional protector.The current study examined the HEXACO model and peoples’ attitudes toward the rule to better understand the academic misconduct behaviors among university students. Our findings have important implications for researchers and institutional educators. We demonstrated that in addition to the tractional big five personality factors, honesty-humility is a unique contributor to decreasing academic dishonesty. Recent studies have suggested focusing on integrity as the broadest defense against dishonesty in all spheres of academiaOur study also linked law-abiding attitudes with academic behaviors. Legal laws and academic rules share features in regulating people’s behaviors by imposing sanctions. They are quite different from social norms, which is a rather indirect way of behavior regulation. The current study confirmed that rule conditionality plays an important role in predicting academic misconduct of university students. Thus law-abiding education and behavior modification interventions might also be effective in preventing academic dishonesty.55. Future research should control and study the links in a longitudinal data set. Finally, although the current research only focused on the impact of individual factors on academic misconduct, contextual factors could be considered using multi-level analysis.Our results have contributed to the academic dishonesty field, but it is not free from limitations. First, it was a correlational study, meaning it is only possible to speak about relationships but not causal links. Experiments are necessary for future research. In addition, we did not control the participant’s prior academic performance. A previous study showed that students with lower than average performance tend to cheat


Solar radiation, which is emitted by the sun, is required to properly operate photovoltaic cells and solar water pumps (SWP). A parabolic trough surface collector (PTSC) installation model was created to investigate the efficacy of SWP. The thermal transfer performance in SWP is evaluated thru the presence of warmth radiation and heat cause besides viscid dissipation. This evaluation is performed by measuring the thermal transmission proportion of the selected warmth transmission liquid in the PTSC, known as a hybrid nano-fluid. Entropy analysis of Oldroyd-B hybrid nano-fluid via modified Buongiorno's model was also tested. The functions of regulating parameters are quantitatively observed by using the Keller-box approach in MATLAB coding. Short terms define various parameters for tables in velocity, shear pressure and temperature, gravity, and Nusselt numbers. In the condition of thermal radiation and thermal conductivity at room temperature, the competence of SWP is proven to be enhanced. Unlike basic nano-fluids, hybrid nano-fluids are an excellent source of heat transfer. Additionally, with at least 22.56% and 35.01% magnitude, the thermal efficiency of AA7075–Ti–6Al–4 V/EO is higher than AA7075–EO. PV technology converts sunlight into electricity through photovoltaic semiconductors2, whereas Solar Thermal is a technology that directly uses solar energy to heat or generate electricity. Solar water heating systems are the technology from Solar Thermal that collect heat through the solar collector to heat water for domestic or commercial purposes3. Using non-renewable fossil fuels in the plantation is to boil water4, which can also be performed by solar thermal technology. Therefore, solar energy is needed to sustain the environment and population growth5. Solar energy usage can be observed in any PV technologies, such as streetlights, solar water propels, profitable power developments, net metering ventures, and solar construction technology6. While agricultural experts question the legitimacy of organic and local food security, grocery shops around the country have begun to stock organic and local food. Organic and locally sourced products are more popular among consumers, and the desire for these items has increased rapidly in recent years. The integration of the natural and local cuisine movements has resulted in a variety of marketing options, ranging from local cuisine units in major supermarkets to farmers' shops and community-based agriculture systems (CSA)7. PV technology, on the other hand, is one of the most common forms of solar systems accessible, and it includes a collection of PV solar panels referred to as solar cell systems8. CSP, or concentrated solar power, is commonly found in vast regions producing grid electricity. CSP solar water heating begins with black paint applied on the leg and is utilised to heat water. Because dark colours capture the heat of the sun, they heat the water within. Although this may appear archaic, it demonstrates that humankind knew the sun's energy from the outset. The heat produced by this mechanism is comparable to the quantity of heat produced by the sun. As a result, countries with scorching suns and tropical climates are more prone to profit from this form of solar energy. This advantage includes the efficacy of such initiatives. As a result, in hot climates, hydropower can be expensive. As a consequence, reimbursement times for solar eclipses are shorter9. Fluid runs through tubes and gathers solar energy in CSP to heat water or create electricity. One issue with this solar power is heat transmission from the sun. Scientists and innovators tried other liquids, such as oil and sodium, yet molten salt proved to be an exceptionally successful alternative. This alternative is good, considering it is more expensive and works better with steam engines. Compared to solar PV, solar power works much better in space. Solar thermal can provide up to 70% efficiency in heat collection10.Solar energy, radiation from the sun, can generate heat, trigger chemical responses, or reproduce electricity. The world's quantity of solar energy is much superior to the contemporary and expected universal energy needs. Solar Photovoltaic (PV) and Solar Thermal11. The solar pressure regulator is driven by electricity supplied by the PV array or radiant heat created by solar light collected. This solar water pump works opposite to a diesel or grid compressor12. In 1983, the creator of the United States, Charles Fritts, documented the very first photovoltaic cells built using water pumps and live electricity in 15 residences. Until 1993, tens of thousands of PV water submersible pumps were deployed globally13. In 1998, this installation had grown to about 60,000 installations14. Pumping water requires the development of a unique machine valve. Since 1968, solar photovoltaic generators have been used in several regions of the world, including SWP15. The massive solar water pump was constructed in 1901 in Pasadena, California, USA16. Next, Harrington of New Mexico was the first to employ CSP to divert water up to 6 m highin 1920. Finally, the literature research demonstrated that SWP utilised PV and CSP to complete its tasks. Parabolic trough solar collection (PTSC) is another form of CSP in which heat transfer fluid (HTF) transports warmth from the hoarder to the heat exchanger to create power17. HTF in PTSC can reach 390 °C in temperature, and it also has these characteristics: low viscosity, pressure, cooling, and storage cost; non-corrosive; and proven to be safe18. Nanofluids have recently been revealed to be particular HTFs with great insulation characteristics. The supreme common nano-materials in nano-fluid are metal and non-metal. Carbon nanotubes (CNT), mono carbon nanotubes (SWCNT), and multi-walled carbon nanotubes (MWCNT) are among the nano-fluid particles included in the computational model and experimental studies in PTSC19.A solar water pump (SWP) system is an electric pump water system for electricity production, where one or more PV panels supply electricity. A standard SWP system consists of a solar panel that empowers an electric motor, which enables a shaft directly above the pump. H2O is usually pumped starting the ground or flowing into a storage reservoir that supplies gravitational force. Thus vitality conservation is not required in these systems20. The Oldroyd-B model was developed by Irfan et al. 21 to analyse the blood flow, and they recommended that the viscoelastic property in bloodshould be considered, especially when the shear values are low. Subsequently, the analytical and numerical models of Oldroyd-B viscoelastic fluid have been reported24. According to Sajid et al.22, using a method of regional variance, the computational complexity for the circulation of the Oldroyd-B aqueous flow separation in a stance phase goes beyond a stretch sheet. The effect of thermal radiation, Joule heating, magnetic field, and thermophoresis has been described by Hayat and Alsaedi23. The analytical model in the capillary under the Debye-Hückel approximation, with the effect of electro-osmotic flow, was solved by Zhao et al.24.The Oldroyd-B model is a fundamental ideal cast-off to describe the flow of viscoelastic fluid, named after its creator Oldroyd3O4 nano-fluid are widely analysed. Baby and Sundara25 reported improvements in thermal performance of 3–5% and 6.5–10% at 0.005% and concentration of 0.03% CNT/Fe3O4 hybrid nano-fluid with a thermal reading of 30–50 ○C. This nano-fluid reveals a non-Newtonian demeanour in more than 6% voltages, and its viscosity decreases as temperatures rise. At a temperature of 30–60 °C and the nanoparticles volume ratios of 0–1%, the ethylene glycol/MgO-MWCNT mixture nano-fluid density was reported by Soltani and Akbari23. A non-Newtonian composite nanofluid comprising CNT/Fe3O4 coated nanoparticles is used as a cooler in a short channel temperature changer, and the viscidness and thermal conductivity were measured26. In that process, to synthesize nano-fluid mixtures, pure ferrofluid was first produced in the manner presented by Berger et al.27. Then, CNT nano-fluid was prepared using the method suggested by Garg et al. It is noteworthy that TMAH and GA were used respectively to coagulate Fe3O4 nanoparticles and CNTs to prevent particle coagulation. In the next step, the hybrid nano-fluid was produced by adding the required amount of CNT nano-fluid to the ferrofluid produced, followed by the sonication of the mixture. Recent works can be found in31.Mixed nano-fluids are novel nano-fluids prepared by forming different nanoparticles in combination or composite form. The impetus for the preparation of composite nano-fluids is the continuous upgrading of warmth transmission with the improved thermal conductivity of these nano-fluids. Among all the hybrid nano-fluids tested, CNT/Fe32. The modified Buongiorno model for partial volume analysis is used to study the bioconvective flow of gyrotactic microorganisms33. Rawat et al.34 applied the improved Buongiorno's Ideal to consider the consequence of chemical and radiation reactions on the magnetic nano-fluid flow bounded in a cone. Rana et al.35 chose alumina and titania particles in their Buongiorno's model, whereas the volatile transport of hybrid nano-fluid over long distances was examined by Ali et al.36. As a result, the random movement of the nanoparticles in36 is known as the Brownian movement37. The pioneer experimental study of Brownian motion observed the coal dust particles in the alcohol38 and pollen grains in the water39. Besides, Albert Einstein formed the mathematical model of the Brownian movement. Garg and Jayaraj40 recently pronounced the vaporizer atom movement and the thermophoresis effect in cylindrical geometry.Buongiorno proposed a non-homogeneous nano-fluid model, where the random movement of nanoparticles and thermo-diffusion effect was found to be the most contributing factors41. The bodies with higher absolute zero temperatures will be able to emit thermal radiation42. The applications of thermal radiation were observed in ultrasound-assisted and microwave-assisted heating methods43. The presence of nanoparticles in the nanofluid, on the other hand, boosts the thermal conductance of the nano-fluid itself, with a minimum percentage of 12%. As a result, measuring variation in the fluidity of nanofluid in conceptual or observational correlations was discovered to be particularly essential44. The thermophysical properties of hybrid nano-fluid (more than one nanoparticle in the base fluid) were reported46, where Adriana45 solved the fluid model numerically and Afrand et al.46 worked on their model by experimenting.Thermal radiation is one type of heat transmission in the form of electromagnetic waves when the bodies in the same system are not in direct physical contact with each other47, and it can be represented by a chemical equation48. The first-order substance response in the fluid flow model was studied by Chambre and Young49 and Ramanamurthy and Rao50 for the case of static horizontal plates49 and cylindrical catalyst pellets50. The thermal properties of hybrid nano-fluid beyond a tempestuous exterior were described by Nadeem et al.51 and Yusuf et al.52. Nadeem et al.51 deliberate the movement of the nano-fluid mixture. In contrast, the radiating nano-fluid and hybrid nano-fluid by the presence of Darcy–Forchheimer absorbent media is studied by Yusuf et al.52. Mabood et al.53 describe the transmission of temperature and mass in nanofluid beyond a spinning frame. Subsequently, articles regarding the warmth transmission and the movement of nano-fluid and hybrid nano-fluid have been published under the effect of velocity slip54, entropy54, radiation56, and melting process56. Furthermore, heat transmission in a liquid nanopore confined by a lateral molten surface is observed58.A chemical reaction is a chemical transformation process from one chemical substance to another. The positions of the electrons are changed, and chemical bonds between atoms will be broken in this reaction59. The addition of nanoparticles to essential fluids can contribute to the entire generation of entropy60. As a result, the incorporation of nanoparticles in the base fluid improves the nano-fluid viscosity and reduces the pressure in the thermal system. Furthermore, the job of nano-fluids is to lower the temperature of the heat pipe, which minimises the amount of heat transmitted to the overall amount of entropy creation. Sciacovelli et al.61 studied the applicability of entropy production to numerous engineering domains. At the same time, Manjunath and Kaushik62 reported second-law entropy generation in the operation of the heater. The model of entropy generation in pore systems is developed by Torabi et al.63. Subsequently, Mahian et al.64 deal with entropy generation in nano-fluid/hybrid nano-fluid flow. The entropy production rate has been found to upsurge in a high concentration of nanoparticles due to the presence of contrasting forces65.Entropy is a measured quantity related to a state of distraction, disorder, or uncertainty. Ludwig Boltzmann, a well-known Austrian physicist, defined enthalpy as the evaluation of conformance amongst tiny processes  and macroscopic systemsHeat transfer analysis researchers are concentrating their efforts on coming up with a timely solution to this problem due to the increasing need for heat management caused by overheating heating systems for various technological and industrial operations. By taking this into account, this study investigates the thermal performance of a solar water pump (SWP) employing mono/hybrid nano-fluids (AA7075–EO and AA7075–Ti–6Al–4 V/EO), as well as a parabolic trough solar collector (PTSC) situated within an SWP. Solar radiation is considered a heat source. The schematic diagram is depicted in Fig. The introduction and the mathematical formulation are positioned in Sect. “In this model, PVC cell sheets (as reported from the previous model of SWP) have been replaced with PTSC.The PTSC cylinder-shaped system has a broader exterior area than PVC sheets, allowing it to capture more solar energy.SWP has a low production and maintenance cost due to solar energy usage.According to the interpretation, the accumulation of nano-materials into the base fluid intensifies the thermal transmission through PTSC by generating additional energy.SWP does not contaminate the air, and it is also environmentally friendly.SWP is useful in third-world or developing nations where alternative sources of energy or water are unavailable.It is presented a theoretical investigation to improve the efficiency of SWP by utilising the benefits of a hybrid nanofluid's thermal characteristics over a PTSC. The PTSC was determined to be installed in many positions in SWP. The following are the current research's objectives:17.Equation 66.The governing equations below Eqs. –5 repres67:The respective boundary conditions shall be The vector of fluid velocity is expressed as 68. Besides, Oldroyd-B hybrid nano-fluid is displayed in the third column of Table 169. The combination of dual diverse nanoparticles in a standard fluid causes an augmentation of heat transmission for the whole fluid.The thermophysical formulation of Oldroyd-B nano-fluid, such as viscosity, density, heat capacity, and thermal conductivity, is shown in the second column of Table 1κ, and 71.The symbols as displayed in Table entclass1pt{minima72 can be written asThe Rosseland approximation17).The boundary values problem contains Eqs. –6 have bHere  in Eqs.  and 11)\document in Eqs. –16:14\doThe notation (') in Eqs. –13 indicThe above equations Eqs. –18 will 73:The entropy generation can be shown in Eq. 73:20\doc74,The dimensionless entropy equation is formulated as However, Eq.  is trans75 developed in MATLAB software. The flow chart of KBM is displayed in Fig. The numerical solutions of Eqs. –12, togeThe higher-order ODEs must be converted to the first-order ODEs, which will produce the new substitutions implemented in the KBM. Dependent variables The domain nts Fig. :Figure 380, as shown in Table The results validation has been done by making a comparison with the previously published reports Bi, radiation factor χ as well as Brinkman number This section includes graphical interpretations of velocity mentclasspt{minimaNG Figs. , 32, 33.As shown in Fig. As shown in Fig. Deborah number When the increment is done in values of mentclasspt{minimaThe slip effect }γ∗ Fig. .Figure 1, and Bi upsurge the thermal boundary layer thickness by inducing the convective heat exchange on the exterior. Meanwhile, the higher heat energy supply is contributed by Variations in The graphical results of the suction parameter can be seen in Figs. sed Fig. . In the F′ω Fig. , \docume(ω) Fig. , and \do}NG Fig. , compareS<0 Fig.  is descrS<0 Fig. . The samS<0 Fig. . But theS<0 Fig. . This haS>0 Fig. .Figure 2The Reynolds number is a dimensionless number for the fluid, defined as a ratio of inertial and viscous forces. It affects the fluid flowing pattern for streamlining or laminar, steady flowing, medium-level, unstable flow (turbulent). Viscous forces serve as a resistor even though inertial forces are the most important factor in a fluid motion. Hence, fluid exhibits turbulent flowing when inertial force has the greatest impact , whereas green indicates hybrid nano-fluid (AA7075–Ti–6Al–4 V/EO). According to a bar chart, hybrid nano-fluid (AA7075–Ti–6Al–4 V/EO) gains a higher heat transport rate than nano-fluid (AA7075–EO).Figure The values of the Nusselt number Increases in The development of entropy diversity is affected by The heat transfer rate is improved under the range of Furthermore, at least 22.56% and a maximum of 35.01%, AA7075–Ti–6Al–4 V/EO temperature efficiency is higher than AA7075–EO.Speed differences tend to be due to improvements in In this paper, the numerical model of the solar water pump (SWP) has been developed, where the principal component in SWP is a parabolic trough surface collector (PTSC). The Oldroyd-B fluid in this model consists of mono nano-fluid (AA7075–EO) and hybrid nano-fluid (AA7075–Ti–6Al–4 V/EO). The controlling factors that are involved in this model are the Biot number, Brinkman number, Deborah number, Reynolds number, heat source, nanoparticle volume fraction, perforated media, radiation parameter, speed slip, viscous dissipation, suction, and injection. Changes in speed, temperature, entropy, concentration, and temperature are depicted, together with the tabulation of the Nusselt number. Therefore, the conclusion is listed below:Future study recommendations include the addition of regulating variables in this current model, replacing existing factors with the right ones, and using new working fluid in PTSC.87.The KBM approach could be applied to a variety of physical and technical challenges in the futureSupplementary Information.


Nepenthes × ventrata , produces passive traps containing digestive fluid. Although reactive oxygen species (ROS) in the fluid were detected in some pitcher plants, the participation of reactive nitrogen species (RNS) in the digestion process has not yet been examined. The aim of this work was to investigate the production of superoxide anion (O2•−), nitric oxide (NO) and peroxynitrite (ONOO−) levels in the digestive fluid of traps throughout organ development. We revealed the ROS and RNS occurrence in the digestive fluid, linked to the ROS-scavenging capacity and total phenolics content. In digestive fluid from the fed traps, NO emission was higher than in the fluid from the developed unfed pitcher. The concentration of nitrite (NO2−) decreased in the fluid from the fed traps in comparison to the unfed ones, pointing at NO2− as the key source of NO. The enhanced emission of NO was associated with lowered content of ONOO− in the fluid, probably due to lower production of O2•−. At the same time, despite a decline in total phenolics, the maximum ROS scavenging capacity was detected. In addition, ROS and RNS were noted even in closed traps, suggesting their involvement not only in digestion per se but also their action as signaling agents in trap ontogeny.The carnivorous pitcher plant,  Plantae carnivorae) are able to attract prey, kill it, digest the body, and absorb released nutrients. This is a relatively unusual method of nourishment for autotrophs, described as the “carnivorous syndrome”. This system of obtaining nutrients from other organisms has made these creatures known as “the most wonderful plants in the world” [Carnivorous plants  converted leaves into jug-shaped containers to lure and trap arthropods and other small animals [Nepenthes contains over 140 species [N. khasiana Hook. f.), Sri Lanka (N. distillatoria L.), Seychelles (N. pervillei Blume), and Madagascar  [kerangas), peat-swamp forests, and mountainous forests [Nepenthes’ growth and development are usually related to the formation of dimorphic traps on the tips of their leaves: “terrestrial” and “aerial” pitchers [N. pudica—underground traps [Nepenthes trap is divided into three zones [Pitcher plants that form pitfall-shaped traps include: Sarraceniaceae, Cephalotaceae, and Nepenthaceae . Nepenth animals . It is c species . These tllinger) ,13. Theipitchers . The firnd traps . The typee zones , which iee zones , and a dee zones . A lid iee zones ,20.2O2) using electrons from different donors, including phenolic compounds (PCs) [Nephenthes traps. Additionally, some other compounds have been noted in digestive fluid, including naphthoquinones [N. gracilis Korth., which is accompanied by the generation of free radicals, mostly hydroxyl radicals (•OH) [Digestion occurs in the presence of different proteins, including Nepenthesins 1 and 2, specific aspartic proteases with broad cleavage specificity, high thermal stability, and optimal activities at acidic pH . Other pds (PCs) . The nutds (PCs) . The prequinones  and flavquinones . More thls (•OH) .2•−), as well as •OH and H2O2, which are produced in plant tissues, mainly in chloroplasts, mitochondria, peroxisomes, and in the apoplast [The incomplete reduction or excitation of oxygen leads to ROS generation . The phyapoplast . The reaapoplast ,33,34. Rapoplast ,32. Theyapoplast . The incapoplast . Cellulaapoplast ,37. POxsapoplast . Furtherapoplast .2•−. NO’s reaction with the latter molecule leads to the formation of peroxynitrite (ONOO−), a potent oxidizing and nitrating agent. The best-known RNS are: NO radical form (•NO), nitrosonium cation (NO+), nitroxyl anion (NO−), and ONOO− [2−) is the key donor of various RNS. Under low pH, the protonation of NO2− leads to nitrous acid (HNO2) formation; subsequently, the formation of different nitrogen oxides (NOx) depends on the actual redox state of the local environment and the presence of molecular oxygen or ROS [2− [Reactive nitrogen species (RNS) are products of nitric oxide (NO) and their reaction with oxygen or Ond ONOO− ,40. RNS nd ONOO− ,41,42. Snd ONOO− ,40,41. In or ROS ,44. Redu ROS [2− . Nitrate ROS [2− ,47.2− application in the growing medium of examined plants stimulated NO liberation even in darkness [2−, which may be the main source of various RNS at acidic pH during digestion; the process carried out in the trap.It is known that ROS may be liberated outside plant tissues, including the digestive fluids of pitcher plants ,48. On tdarkness . No dataNepenthes × ventrata throughout their organ development until their aging.The aim of this work was to determine the alterations in ROS levels and RNS production in the digestive fluid of We hypothesize that ROS and RNS act as signaling molecules that regulate development of the trap and digestion process. We propose the presence of ROS–RNS crosstalk in digestion fluid, from the trap’s formation until the trap’s ageing.2•− production was in the digestive fluid of the closed traps (9 nmol min−1 mL−1)  . In the In the unfed, developed traps, the total capacity of the free-radical reduction was the lowest. One day after feeding, the total free-radical-scavenging capacity was the highest in the studied model. In the digestive fluid of the closed traps, just-opened traps, and aged traps, the total capacity of the free-radical reduction was at a similar level, of about 5% .−1 digestive fluid). An increase in the PCs content was observed in the digestive fluid taken from the unfed developed traps. This increase was more than 2.5 times that observed in the closed traps. The total PCs content in the digestive fluid of the fed traps and aged traps was at similar levels, about 1.8 µg mL−1 digestive fluid   The loweThe highest fluorescence of APF was in the digestive fluid of the developed but unfed traps (50.2 U). In the digestive fluid of the closed, freshly opened, fed, and aged traps, the fluorescence of APF was at a similar level, of more than 5 U but below 10 U .2− concentration was the highest (1.1 nmol mL−1 digestive fluid). The NO2− concentration in the digestive fluid of closed, just opened, fed, and aged traps was at a similar level, about 18 µg mL−1 digestive fluid  seeds was accompanied by ROS and POx release [2O2 into the germination medium of apple  embryos and from tomato (Solanum lycopersicum L.) seedlings was also shown [N. alata Blanco are the digested products of the exogenously oxidized proteins. Subsequently, Chia et al. [•OH in N. gracilis Korth. digestive fluid. The authors proposed that this free radical initiates and facilitates the digestion of proteins or peptides. ROS involvement in proteolysis has been shown as protein degradation is facilitated by irreversible oxidation, mostly carbonylation [Nepenthes plants that the secreted fluid is bacteria-free and unsuitable for microbial growth [N. alata pitchers [2O2 content [N. ventrata, although a higher level of PCs in the mature but not artificially fed traps may point to the protective role of these compounds in plant–microbe interactions. Some of these compounds may also be of microbial origin [Apoplastic ROS production is known to have an important regulatory effect . Moreove release . The autso shown ,51, poinso shown  demonstra et al.  confirmenylation ,53. The l growth . Hence, pitchers . By contpitchers . An envipitchers . The decpitchers . As subs content . We prop content . The POxl origin .N. ventrata trap fluid. The presented data strongly suggest that the digestion process is accompanied by increased RNS generation (detected as NO formation using the fluorescence method) in the pitcher fluid. Moreover, during trap development, changes in RNS level were observed. The lowest NO formation was noted in the closed traps and the just-opened traps. Nevertheless, the NO is clearly of plant origin. The question that arises is what the NO function is at the very beginning of the functioning of traps. The mature, opened, but unfed traps was characterized by higher NO levels in the trap fluid than in the fluid of immature or closed traps. The function of NO remains unknown. High NO levels in the fluid during digestion strongly points to the involvement of RNS in this process. We propose two roles of RNS. The first is linked to the ROS modulation by NO; the second is linked to the RNSs’ action as protein modifiers. We also do not exclude the involvement of RNS- or NO−-modified molecules in long-distance signaling in the course of prey digestion. By analogy with the action of ROS, the modifications of proteins of a reversible or non-reversible nature fulfill two functions: the modification of the target protein activity and the stimulation of proteolysis. However, the question of whether NO formation after opening the trap is due to the plant’s activity or to the activity of microorganisms inside the trap requires further investigation. The release of NO from plants into the surrounding environment as a response to different stimuli  was confirmed [2− addition, and this is a physiological reaction common to all plants [2− content in the digestive fluid. Firstly, very low levels of these ions were detected in the closed and just-opened traps. These findings are in agreement with data concerning trace amounts of nitrate (NO3−) in the fluid of closed N. alata pitchers [2− content was characteristic for the fed traps, after one day of digestion. These results suggest that the major source of NO in the digestive fluid may be NO2−. The protonation of NO2− occurs under low pH (similarly to the human stomach), leading to the formation of dinitrogen trioxide (N2O3), a strong nitrosating agent (equations below). Further NO and radical nitrogen dioxide (NO•2) are formed in the reaction of disproportionation. This NO formation requires both high NO2− concentration and low pH [There are no research data that confirm the formation, liberation or generation of NO in pitcher fluid, especially during the digestion process. Our results demonstrated for the first time that RNS are present in onfirmed . It has l plants . Our respitchers . Furtherd low pH .2NO2− + 2−. We propose that it is of both plant and prey origin. NO2− may be formed from NO (generated in plant tissues or produced by microbes), which reacts with oxygenated hemoproteins in a process called NO deoxygenation, catalyzed by hem-containing proteins, including hemoglobins [− formation in pitcher fluid. The lowest ONOO− levels were noted for the closed and just-opened traps, corresponding to the lowest NO emission and NO2− content in the analyzed fluid at these developmental stages of the organ. As ONOO− is a strong nitration agent, it may interfere with the formation of a relationship with microorganisms, or it may modify necessary enzymes and other proteins involved in prey digestion. The highest levels of NO2−, the intense generation of O2•−, and ONOO− formation were characteristic of a fully mature trap “ready” to catch prey. By contrast, even if digestion is accompanied by high NO formation in the digestion fluid, the NO2− content and the ONOO− formation are decreased. This points to the presence of strongly regulated NO biochemistry in digestive fluid during prey decomposition.The question arises as to the source of NOoglobins , which aoglobins . These r2− level increases. It can be assumed that this tissue acts as a nutrient donor before abscission from the plant. High concentrations of NO2− at this stage are probably not linked to NO generation but, instead, they may protect against pathogen growth and mold development. Nevertheless, further research should be undertaken to confirm this hypothesis.The ageing of traps is the last developmental stage along with the decrease in ROS and RNS formation, even as the NONepenthes × ventrata Hort. ex Fleming ) were used as plant materials. Plants were grown in a greenhouse under conditions of high humidity (60%), controlled temperature (28 °C), and natural light (spring–summer season). Plants were grown in a mixture of acid peat and perlite with sphagnum moss, and they were watered with rainwater every other day. After opening, pitcher-trap inlets were covered with a single layer of sterile gauze to control prey intake. For experiments, traps at various stages of development were selected: closed traps (Drosophilla melanogaster) (live flies were placed in a fluid of the trap using forceps) or egg-white solution  was added to the pitchers. To measure NO and ONOO− generation, traps were fed with fruit files. Each of developmental type of trap was examined on separate plants. The digestive fluid was collected and used for analyses; after short centrifugation , the obtained supernatant was transferred to the sterile tubes for further analyses.Mature pitcher plants ed traps a, just-oed traps b, fully ed traps c, fully solution d, and trsolution e. To mea2•− was conducted according to Misra and Fridovich [−1 cm−1. The results were expressed as the production of nmol O2•− min−1 mL−1 of digestive fluid. The measurements were conducted in three independent experiments, each in at least three biological replicates.Measurement of oxidation of epinephrine by Oridovich . Digestiw/v) methanol. The reaction mixture was incubated for 15 min in darkness at room temperature. DPPH concentration was measured at 517 nm using a microplate reader . Antioxidant capacity was expressed as reduction of DPPH defined as ((A0 − As)/A0) × 100%, where A0 is absorbance of a blank and As is absorbance of the sample. Experiments were conducted in four independent replicates with three repetitions in each.Total capacity of the reduction of the free radicals in the digestive fluid was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) . The digw/v) sodium-carbonate solution was added into the mixture. After incubation of the mixture for 30 min in darkness at room temperature, the content of total PCs was measured at 765 nm using spectrophotometer Hitachi U-2900 . Blanks were prepared as described above with the replacement of a digestive fluid with distilled water. The standard curve was created using gallic acid  as a standard. Total PC content was expressed as µg per pitcher−1 . Experiments were performed in four independent replicates with three repetitions in each.Content of total PCs in the digestive fluid was determined using the Folin–Ciocalteu reagent. The digestive fluid (730 µL) was mixed with 70 µL of the F–C reagent (MFCD00132625) and incubated for 5 min in darkness at room temperature. After incubation, 100 µL of 7.5% . A stock solution of DAF-FM DA was prepared according to manufacturer’s guidelines.−1 of digestive fluid. The measurements were performed in 4 repetitions, and their exact reproducibility was confirmed.Into the mixture of 1.9 mL of digestive fluid and 100 µL of 100 mM Tris-HCl buffer pH 7.4 was added a 2 nM solution of DAF-FM DA (5 µL). Fluorescence was recorded for 2000 s  at constant temperature of 23 °C using Hitachi F-2500  spectrofluorometer. As the negative controls, the digestive fluid was replaced with distilled water. The combination of 2.0 mL of 10 mM Tris-HCl buffer, pH 7.4, mixed with the solution of 2 nM DAF-FM DA (5 µL) was used for 1 arbitrary unit calculation. The value of 1U describes the minimum and maximum fluorescence Δ. The results were expressed as arbitrary U per mL− generation in digestive fluid was measured using 30-(p-aminophenyl)fluorescein , following the manufacturer’s instructions. APF sensitivity is associated with the presence of ONOO− but also •OH and hypochlorite [ONOOchlorite .−1 of digestive fluid and expressed in arbitrary units (U). The 1U was estimated from the result obtained for the maximal intensity of the fluorescence for the probe without APF. Measurements were conducted in 3–4 independent experiments with three repetitions in each.Fluorescence was recorded for 2000 s  using the Hitachi F-2500  spectrofluorometer. A final intensity of fluorescence was taken into calculations. The results were calculated per 1 mL2−-concentration measurement was conducted using Griess reagent , following the manufacturer’s instructions. Digestive fluid (1 mL) was mixed with 50% trichloric acid (2 µL), and vigorously vortexed. Transparent fluid (75 µL) was applied into the 96-well plates containing 75 µL of Griess reagent. After 15 min of incubation in darkness at room temperature, the absorbance was read at 540 nm using microplate reader . Determination was performed in the three independent experiments. NO2− concentration was calculated using a standard curve prepared from sodium nitrite (NaNO2) dissolved in 10 mM Tris–HCl pH 7.4. Concentration of NO2− was expressed as nmol per mL−1 of digestive fluid.The NOAll data were obtained in at least 3 independent experiments. The plants were selected randomly for the experiments from 55 individuals; only “aerial” traps were used. Data were analyzed using Statistica Software. Mean values were calculated and SD was provided. After one-way ANOVA, homogenous groups were evaluated using Fisher’s LSD post hoc test.Nepenthes may be described as an “external stomach”, as these plants digest prey in the lumen of the traps. In our experiment, a comparison of the changes in the ROS and RNS content in the fluid of developed and fed traps point to a contribution of these molecules to the digestion process of pitcher plants. The presented data indicate that digestion is linked to the emission of NO, as the fluid from the fed-trap NO level was higher than that from the developed pitcher fluid. One of the most important sources of NO could be the acidification of NO2−, as the concentration of these ions decreased in the fed traps in comparison to the developed traps. Although the nourishment of the plant with an animal or proteins results in the enhanced emission of NO, it is associated with decreased content of ONOO−, probably due to the lower production of O2•− at the same time, which may be a consequence of maximal ROS scavenging capacity at this developmental phase of the trap. In addition, because of the relatively low PCs content in the digestive fluid from the fed trap, enzymatic antioxidants could be the most important factors in the regulation of ROS levels during digestion. Thus, there is no doubt that digestion in pitcher plants is linked to ROS and RNS; however, due to the limitation of the experimental data, further investigations of the activity of enzymatic antioxidants and the concentrations of other ROS or ROS/RNS-dependent protein modifications should be carried out, in order to build up a comprehensive view of the regulation of this process.Pitchers of


The size of the tumour is of clinical relevance in testicular tumours. Our statistical analysis of 641 cases with testicular tumours revealed that 50% of cases with tumours smaller than 1 cm were of benign histology. The frequencies of both metastatic spread and elevations of serum tumour markers increase with growing tumour size. The novel tumour marker microRNA-371a-3p (M371) outperforms the classical markers and is measurable in 44% of germ cell tumours with tumour sizes below 1 cm.The role of primary tumour size (TS) in the clinical course of testicular tumours is incompletely understood. We retrospectively evaluated 641 consecutive patients with testicular neoplasms with regard to TS, histology, clinical stage (CS), serum tumour marker (STM) expression and patient age using descriptive statistical methods. TS ≤ 10 mm was encountered in 13.6% of cases. Median TS of 10 mm, 30 mm, 35 mm, and 53 mm were found in benign tumours, seminomas, nonseminomas, and other malignant tumours, respectively. In cases with TS ≤ 10 mm, 50.6% had benign tumours. Upon receiver operating characteristics analysis, TS of > 16 mm revealed 81.5% sensitivity and 81.0% specificity for detecting malignancy. In subcentimeter germ cell tumours (GCTs), 97.7% of cases had CS1, and CS1 frequency dropped with increasing TS. Expression rates of all STMs significantly increased with TS. MicroRNA-371a-3p (M371) serum levels had higher expression rates than classical STMs, with a rate of 44.1% in subcentimeter GCTs. In all, TS is a biologically relevant factor owing to its significant associations with CS, STM expression rates and histology. Importantly, 50% of subcentimeter testicular neoplasms are of benign nature, and M371 outperforms the classical markers even in subcentimeter tumours. The clinical status of testicular tumours is characterized by the parameters primary tumour size, patient age, histology of the primary, serum tumour marker elevations and the extent and distribution of metastases . These features represent simple clinical factors, and the clinical usefulness of each factor has stood the test of time ,2,3,4,5 Obviously, there are manifold interrelationships between tumour size and other clinical characteristics of testicular neoplasms. A number of studies had analysed single issues regarding the clinical role of tumour size ,16,17,18(Assumption #1) The size of a testicular new growth is associated with histology in the way that a much higher proportion of benign tumours are found among primary testicular neoplasms sized < 1 cm than among the larger ones. (Assumption #2) Primary tumour size has an impact on clinical staging in germ cell tumours (GCTs), with fewer advanced clinical stages in small tumours and more advanced stages in larger tumours. (Assumption #3) Tumour size is associated with the expression rates of the classical serum tumour markers in GCTs as well as with the novel marker M371. Lower frequencies of marker elevations are expected in small tumour sizes, and higher expressions in larger tumours. The new tumour marker M371 is much more frequently expressed than the classical markers bHCG and AFP. (Assumption #4) An interrelationship between patient age and primary tumour size is hypothesized in a way that older patients will have larger tumours.Therefore, we analysed tumour size in a large patient sample and looked for associations with histology of the primary, clinical staging, serum tumour marker expression rates, and with age. In particular, we sought to assess the following four assumptions, most of which are already supported by some pieces of evidence; however, the levels of evidence have not reached high levels so far: All consecutive patients, aged 17–98 years, undergoing surgery for a newly diagnosed testicular mass in two Hamburg-based departments of general urology (Albertinen-Krankenhaus and Asklepios Klinik Altona) during 2012–2021, were included in the present retrospective study. Patients submitted to orchiectomy after previous chemotherapy were excluded. The following parameters were abstracted from archival case files: size of the testicular mass (mm) as recorded in the pathology reports, patient’s age (years), histology of the surgical specimen categorized as seminoma (SE), nonseminoma (NS), benign tumour (BT), malignant tumour other than GCT (OM), clinical stage (CS) (only in GCTs); and preoperative expression of serum tumour markers bHCG, AFP, LDH, and M371. About one third of the patients had been included in previous investigations on various other issues ,19.In case of multiple separate tumours in one testicle, the diameters of each tumour were added up to the final tumour size. Simultaneous bilateral tumours were excluded from this analysis. Histological diagnoses were retrieved from pathology reports without central pathology review. Clinical stages were recorded as CS1; CS2a,b; CS2c; and CS3 according to current guide-lines . Serum tEthical approval was provided by Ethikkommission der Ärztekammer Hamburg on 2 March 2020 (PV7288). As solely anonymized patients’ data were evaluated in the present study, the need for informed consent of patients was waived by the ethical committee. All study activities were conducted according to the Declaration of Helsinki of the World Medical Association as amended by the 64th General Assembly, October 2013. All patient data were originally filed in a commercially available data base  and subjected to data validation prior to statistical analysis. For descriptive analysis of nominal variables, absolute frequencies, percentages and 95% confidence intervals (CIs) were presented. Continuous variables were descriptively analysed by calculating measures of location and dispersion, such as median, first quartile (Q1), third quartile (Q3), interquartile range (IQR), minimum, maximum, arithmetic mean and standard deviation. For graphical presentation, box and whisker diagrams were created; the respective boxes were defined by Q1, median and Q3, and the whiskers were defined by the largest and lowest observed values that fell within the 1.5 times IQR measured from Q3 and Q1, respectively. To test for any differences in the distribution of tumour sizes between more than two subgroups of patients defined by age and histology, Kruskal–Wallis tests were applied; these were replaced by Wilcoxon two-sample tests in case of two categories. Chi-squared tests were used to compare contingency tables of nominal variables. To assess whether malignancy rates of testicular neoplasms or tumour marker expression rates increased with tumour size, Cochran–Armitage trend tests were applied. The Jonckheere–Terpstra test served to assess whether tumour sizes increased with clinical stage. To assess the ability of the tumour size to predict malignant histology, a receiver operating curve (ROC) was created. The area under the curve (AUC), together with its 95% Wald confidence interval, was calculated to quantify the goodness of prediction. Youden’s index, defined as the maximum vertical distance between the ROC curve and the diagonal line, was used to identify the optimal cutoff of the tumour size for malignancy prediction. Additionally, the predicted probability curve for malignant histology with bounding 95% confidence intervals was calculated using a linear logistic regression model. Due to the high completion rate of patient data sets, all patients were eligible for most of the analyses listed above. Only serum tumour marker expressions  were not available in all patients. Thus, respective statistical analyses were performed with varying sample sizes according to the available entries. p-values of less than 5% were considered statistically significant in this paper.Statistical analysis was performed with SAS software package version 9.4  on the Windows platform. n = 641) was 30 mm (IQR 15–45 mm). Tumour sizes of ≤10 mm were found in 13.6% of patients, while 45.2% of patients presented with tumour sizes > 30 mm. A total of 641 patients with a median age of 38 years were included in the present analysis. The frequencies of the four histologic subgroups with corresponding median ages are given in p < 0.0001). The median tumour sizes found in germ cell tumours and in the four histologic subgroups are delineated in Results of the comparisons of median tumour sizes between particular histological subgroups are listed in Tumour sizes of seminomas and nonseminomas were not significantly different from each other. However, median GCT tumour size (SE + NS) was significantly larger than that of benign tumours (BT), while OM were significantly larger than GCTs (SE + NS) and BT. A typical example of a small benign tumour is given in The frequencies of the four histologic subgroups in tumour size categories ≤ 10 mm and >10 mm, respectively, are shown in In the subcentimeter category, benign tumours represented more than half of the cases. In the larger tumour size category, seminomas predominated with 59.6%, while benign tumours comprised only 6.3%.A more granular analysis with histologic subgroup frequencies in tumour size categories ≤ 10 mm; 11–20 mm; 21–30 mm; and >30 mm is provided in p < 0.0001, chi square test). If benign tumours (BT) were compared with all malignant tumours (GCT + OM), it became clear that in subcentimeter testicular neoplasms, more than half of all cases represented benign tumours, while decreasing relative proportions of this subtype were observed in categories with increasing tumour sizes . The ROC analysis in An inverse distribution of frequencies was found among the malignant tumours. The trend towards lower proportions of BT and higher frequencies of malignant tumours (GCT + OM) in increasing tumour size categories was highly significant .p < 0.0001, Kruskal–Wallis test). p < 0.0001; Cochran–Armitage trend test). p < 0.0001, Kruskal–Wallis test).The median tumour sizes with IQR and ranges in the four clinical stages are provided in p < 0.0001, chi square test).M371 had the highest expression rate of all tumour markers in both size categories. Somewhat higher expression rates were observed if only germ cell tumours were evaluated , but agap = 0.1039, chi-squared test). Notably, 44% of CS1 patients with tumours ≤10 mm showed elevations of M371 levels, while each of the other markers were expressed in less than 10%.p < 0.0001; seminoma p = 0.9133). M371 revealed the highest expression rates in all size categories. p = 0.0117).p = 0.0161), but the difference between the youngest and the oldest age categories was only 1.5 years, and the inter quartile ranges widely overlapped. Thus, no clear association between age and tumour size could be documented. However, there was no clear trend towards larger tumours in older patients or vice versa. The present study thoroughly analysed the clinical influence of tumour size on presenting features of testicular neoplasms. One main result was that subcentimeter tumours comprised around 13.6% of all testicular new growths, which represented a frequency that had not been clearly specified before. Other central results were the significant associations of primary tumour size with the three factors histology of the primary, clinical staging, and serum tumour marker expression. 3 for GCTs, which would correspond to a mean diameter of only 25 mm [The median sizes of seminomas and nonseminomas in the present study were 30 mm and 35 mm, respectively, with no significant difference between the two subtypes. This result is consistent with sizes of 35 mm found in both seminoma and nonseminoma in a Swiss study . Similarly 25 mm . From Tely 25 mm . Howeverly 25 mm ,25,26,27ly 25 mm , and witly 25 mm . Of note, 13.6% of all tumours in the present study were within the subcentimeter range. During the last two decades, a plethora of studies reported on incidentally detected small testicular tumours; however, the relative frequency of such findings remained rather ill-defined . A largeBenign tumours were shown to have a median size of only 10 mm, which is significantly smaller than that of GCTs (30 mm) and other malignant tumours (53 mm). More than 50% of all testicular tumours in the size category ≤10 mm consist of benign tumours, and we also noted a significant trend towards higher proportions of benign tumours with decreasing tumour size. Thus, small size of a testicular lesion appears to be a strong indicator of benign histology, and this result is in line with several previous reports ,40,41,42Though all of these investigations principally support the potential value of tumour size in predicting testicular histology, there is currently no consensus about the threshold sizes for clinical decision-making . Caution comes from a recent study from Switzerland reporting metastatic disease in 5 of 25 patients (20%) with small germ cell tumours . The autThe present study documented a clear association of tumour size with clinical stage. In the size category ≤10 mm, 97% of cases had localized disease (CS1). The median tumour size increased with increasing clinical stages, with a size of only 30 mm in CS1 and 50 mm in CS3. Very similar results were reported from the classical Dateca series where 84% of seminomas were sized <2.5 cm and had CS1 disease, whereas in the largest size category (>8.5 cm), only 43% had CS1. Likewise, in nonseminomas sized <2.5 cm, 71% of cases had CS1, as opposed to 42% in the largest size category . The ManSignificantly higher expression rates of all serum tumour markers were observed in the tumour size category >10 mm than in smaller tumours (≤10 mm). As serum markers are secreted from both the primary tumour and its metastases, the biological impact of tumour size on marker expression is best evaluated in localized disease (CS1). Here again, marker expression rates were significantly higher in the larger tumour size category (>10 mm), with the exception of LDH. The non-significant difference between the tumour size categories regarding LDH expression rate may relate to the low specificity of this marker for germ cell tumours. p = 0.9133) and M371 in nonseminoma (p = 0.0745). The two exceptions accord with expectations, since there was basically no AFP expression in seminoma, and hence no difference between tumour size categories regarding the expression of this marker. With respect to M371, the expression rate in nonseminoma was extremely high, with 66.7% even in the smallest size category; therefore, the difference relative to the larger size categories was comparatively small (100%). In light of the rather small sample size  the difference was no more significant, statistically. In all, these data clearly demonstrate the close association of serum-marker expressions with tumour bulk, and this result is consistent with the finding of higher serum levels of bHCG and AFP in patients with larger primary tumours than in those with smaller ones [In a more granular analysis evaluating marker expression rates in five tumour size categories, significant trends towards increasing marker expression rates with increasing tumour size were disclosed. This trend was found in both seminoma and nonseminoma, with the exceptions of AFP in seminoma (ler ones . In anotler ones . In semiler ones . In a smler ones . With reler ones . Supportler ones . OverallIn the entire population of patients and also in the population of germ cell tumours, the largest median tumour sizes were observed in the oldest age category. Although the overall analysis revealed significant differences in median sizes among age categories, no clear trend of varying tumour sizes with age categories became apparent. Moreover, the youngest age category proved to present with the second largest tumour size, with only a 1.5 cm difference between the oldest and youngest category. These results are consistent with a previous investigation where no difference in tumour sizes had been found by comparing GCT patients <50 years with older ones . Thus, tThe retrospective study design could be a limitation to the present analysis because selection bias cannot entirely be ruled out. Small sample sizes in the histological subgroups BT and OM could have limited statistical power in spite of the overall large patient number in the study. Histological diagnoses relied on local pathological assessments only, with no central histopathological review. However, as both of the urologic departments participating in the present study had a clinical focus on testicular cancer, local pathologists clearly had suitable experience with testicular pathology. Misclassification of benign tumours cannot entirely be ruled out, since malignancy in some of these cases can only be documented by development of metastases during follow-up. However, as only one quarter of BTs had follow-up periods of less than 2 years, we believe that misclassification of BTs is probably only a minor problem. Missing information regarding therapeutic outcome might be another shortfall; however, the present investigation specifically aimed to analyse the biological role of tumour-size with regard to presenting features of testicular neoplasms. One possible strength of the study is the large number of patients with measurements of the novel tumour marker M371, featuring the utility of this test in clinical practice. Another asset could be the rather large number of patients with small testicular neoplasms, underscoring the utility of the factor of tumour size as a valuable tool in assessing such lesions.The present study confirmed the significant biological role of tumour size in the clinical course of testicular neoplasms. In the diagnostic work-up of small testicular neoplasms, the factor of tumour size may be implemented clinically since more than 50% of cases with testicular new growths sized ≤10 mm had benign histologies. This knowledge may help in avoiding unnecessary orchiectomies and may open the door for a wider application of testis sparing surgery in these cases . Increas


Four other β-lactamase inhibitor combinations (BL/BLI) have been recently approved by the US FDA: ceftazidime-avibactam (CAZ-AVI), ceftolozane-tazobactam (C-T), meropenem-vaborbactam (MEM-VAB), and imipenem-relebactam (IMI-REL). We evaluated the n=187) and 12 European countries  in 2018-2021 and susceptibility tested by CLSI broth microdilution method.383 PSA isolates (1/patient) were recovered from 35 medical centers in the US  was the most active agent, followed by IMI-REL (94.7%/92.5%S in US/EU) and C-T (89.8%/91.3%S in US/EU). MEM-VAB (not approved for PSA in the US) and MEM showed similar activity. Tobramycin (TOB)-S rates were 73.3%/85.7% in US/EU (Table 1). Among TOB-non-S (NS) isolates, 84.6% were CAZ-AVI-S and 73.1% were inhibited at ATM-AVI MIC of ≤8 mg/L. CAZ-AVI retained good activity against C-T-NS (61.1%S), IMI-REL-NS (62.1%S), piperacillin-tazobactam (PIP-TAZ)-NS (86.7%S), meropenem (MEM)-NS (86.6%S), and ciprofloxacin (CIP)-NS (92.1%S) isolates (Table 2). Multidrug-resistant (MDR) and extensively drug-resistant (XDR) phenotypes were observed among 40.1%/30.1% and 24.6%/16.8% of isolates from US/EU, respectively. Among MDR isolates, 90.7%/84.7% were CAZ-AVI-S, 65.3%/66.1% were inhibited at ≤8 mg/L of ATM-AVI, and 78.7%/76.3% were TOB-S in US/EU. CAZ-AVI and TOB retained activity against 87.0%/75.8% and 39.1%/63.6% of XDR isolates in US/EU, respectively.ATM-AVI inhibited 83.4%/85.2% of isolates from US/EU at ≤8 mg/L. CAZ-AVI (MICATM-AVI and CAZ-AVI exhibited potent activity against PSA isolated from CF patients in US and EU and retained good activity against isolates resistant to other antimicrobials, including MDR and XDR organisms; both compounds showed greater activity than TOB. ATM-AVI and CAZ-AVI may represent a valuable option to treat CF patients with pulmonary exacerbations due to PSA infection.Helio S. Sader, MD, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|Melinta: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Pfizer: Grant/Research Support Leonard R. Duncan, PhD, AbbVie: Grant/Research Support Rodrigo E. Mendes, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Office for Assistant Secretary of Defense for Health Affairs: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support|Spero Therapeutics: Grant/Research Support Mariana Castanheira, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support.


The incidence of postoperative morbidity after pancreaticoduodenectomy (PD) is high; however, whether fluid management after surgery affects postoperative morbidity is unclear. This study aimed to determine whether fluid balance in patients undergoing PD is associated with postoperative complications and mortality.Data from a computer-based database of patients who underwent PD between 2016 and 2019 were retrospectively analyzed. Patients were stratified into four quartiles according to their fluid balance at 0–24, 24–48, 48–72, and 72–96 h after surgery. The predefined primary outcome measures were morbidity and mortality rates.P < 0.05). Patients with a fluid balance of 4212 mL during the postoperative 0–72 h were most likely to develop complications (P < 0.001). The area under the receiver operating characteristic curve was 0.71 (0.65–0.77), with a sensitivity of 58.24% and a specificity of 77.10%.A total of 301 patients were included. The morbidity and mortality rates in the cohort were 56.5% and 3.7%, respectively. The most common complications after PD were postoperative pancreatic fistula (31.9%) and delayed gastric emptying (31.6%). Patients with a higher fluid balance in the 0–24-, 24–48-, and 48–72-h postoperative periods had a higher morbidity rate and longer hospital stay than those with a lower fluid balance (all Higher postoperative fluid balance seems to be associated with increased morbidity after PD compared to lower fluid balance. Surgeons should pay close attention to the occurrence of complications in patients with a high fluid balance.The online version contains supplementary material available at 10.1007/s00423-022-02443-6. Pancreaticoduodenectomy (PD) remains one of the most challenging surgical procedures and has the highest complication rate among all abdominal surgical procedures. Although the perioperative mortality rate associated with PD has decreased in recent decades from >20% to <3%, especially in high-volume centers , the morPerioperative fluid management can be challenging. The effects of third spacing and evaporative losses in decreasing extracellular fluid volume have led to the use of traditional aggressive intravenous fluid support, especially during complicated operations such as PD.  However,Patients who underwent PD between April 2016 and February 2019 were retrospectively analyzed. The inclusion criterion was undergoing the PD procedure. Patients who underwent other surgical procedures because of metastasis or changes in the surgical plan  were excluded. A computer-based database was searched for data including age, sex, surgical procedure, pathologic characteristics, length of hospital stay, morbidity, and mortality. The body surface area was calculated using height and weight measurements. All surgical procedures were performed by a single experienced surgeon (RYQ). Fluid intake and output data were collected at 24, 48, 72, and 96 h postoperatively. Fluid balance was defined as the intake volume minus the output volume at each time interval. For analysis, patients were divided into quartiles according to the overall fluid balance during each time interval . The predefined primary outcome measures were morbidity and mortality rates. Morbidities were graded using the Clavien–Dindo classification system . AKI wasP < 0.05. Statistical analyses were performed using IBM SPSS  and SAS .The summary statistics of the study population were tabulated. The area under the receiver operating characteristic curve of fluid input was calculated. The cutoff value of fluid input for identifying morbidity was obtained and evaluated for sensitivity and specificity. Statistical significance was set at A total of 304 patients underwent PD during the study period. Three patients with missing data were excluded from this study. The demographic data of the remaining 301 patients are presented in Table The postoperative morbidity rate in the cohort was 56.48%, and the morbidities were predominantly Clavien–Dindo grades III and IV Table . The mosThe fluid intake during the first 24 h after surgery ranged from 1790 to 13,464 mL, and the output ranged from 700 to 5600 mL. The fluid intake during the 24–48-h postoperative period ranged from 2231 to 9804 mL, and the output ranged from 1095 to 7365 mL. The fluid intake during the 48–72-h postoperative period ranged from 750 to 18,299 mL, and the output ranged from 985 to 7205 mL. Lastly, the fluid intake during the 72–96-h postoperative period ranged from 750 to 14,584 mL, and the output ranged from 476 to 7244 mL.Univariate analysis revealed that patients in the higher quartiles of fluid balance were more likely to have higher morbidity rates and longer hospital and ICU LOS in the 0–24-, 24–48-, and 48–72-h postoperative periods than those in the lower quartiles; however, no significant differences were found in these parameters according to fluid balance in the 72–96-h postoperative period Tables  and 2. AP = 0.001, P < 0.001, P < 0.001, and P = 0.095, respectively). Sensitivity and specificity testing for each period was performed to determine the best cutoff point for discriminating between excessive and non-excessive fluid balance. The optimal fluid balance values were 1730 mL for the 0–24-h postoperative period , 1684 mL for the 24–48-h postoperative period , and 616 mL for the 48–72-h postoperative period  .Receiver operating characteristic curves were created to evaluate the relationship between fluid balance and morbidity at each postoperative time interval. The areas under the curve for the 0–24-, 24–48-, 48–72-, and 72–96-h postoperative periods were 0.62, 0.66, 0.67, and 0.56, respectively (4%) Fig. . When th4%) Fig. . PatientThe negative effects of excessive fluid overload in the postoperative period have long been recognized –16. A coThe present study examined the role of postoperative fluid balance in patients undergoing PD, with a focus on four consecutive postoperative time intervals. Compared with patients in the lower quartiles of fluid balance, those in the higher quartiles had increased incidences of POPF, hemorrhage, DGE, ARDS, SIRS, and overall morbidity, in addition to longer ICU and hospital LOS. The differences in the incidences of these adverse events according to fluid balance quartiles were more pronounced in the 24–48- and 48–72-h postoperative periods. The same conclusions were obtained after adjusting for the individual body surface area.Various studies have discussed how to best regulate and manage fluid balance during the perioperative period, and the recommendations have changed from the initial regimen of liberal fluid intake to the currently used restricted fluid balance regimen . Many stPOPF is a major concern after PD. In our study, the incidence of POPF was higher in patients in the higher quartiles of fluid balance than in those in the lower quartiles throughout the entire 0–72-h postoperative period. This trend was particularly obvious in the 48–72-h period, during which nearly half of the patients (36 of 75) in the highest quartile of fluid balance had POPF compared to less than a quarter of patients in the lowest quartile (17 of 75). It seemed that a higher fluid balance after PD was associated with a higher POPF rate, which was consistent with the findings reported by Wang et al. In 1972, an animal study showed that increasing the fluid balance aggravates tissue edema, which impairs oxygen diffusion, decreases tissue oxygen tension, and leads to worse healing . Another28Excessive fluid intake is associated with cardiopulmonary events after a major surgery. A perioperative positive fluid balance of >2000 mL has been reported to increase the risk of cardiovascular complications by 2.5 times . In the The present study had some limitations. First, this was a single-center retrospective analysis; thus, the inherent bias in this type of research should be considered. Second, daily weight changes were not thoroughly investigated, although such data can also provide evidence of the degree of fluid overload and can be used to scrutinize the results. Third, the effects of fluid type  and quantitative data on fluid intake were not evaluated.The present study investigated a large cohort of patients who underwent PD and found that an increased fluid balance in the early postoperative period (0–72 h after surgery) was associated with increased incidences of overall morbidity, POPF, DGE, and ARDS, as well as longer hospital and ICU LOS. In patients with a high postoperative fluid balance, particularly in the first few days, surgeons should pay close attention to the occurrence of complications.ESM 1(DOCX 64 kb)