The first years of life might be critical for encouraging independent walking in children with cerebral palsy (CP). We sought to identify mechanisms that may underlie the impaired development of walking in three young children with early brain lesions, at high risk of CP, via comprehensive instrumented longitudinal assessments of locomotor patterns and muscle activation during walking. We followed three children (P1–P3) with early brain lesions, at high risk of CP, during five consecutive gait analysis sessions covering a period of 1 to 2 years, starting before the onset of independent walking, and including the session during the first independent steps. In the course of the study, P1 did not develop CP, P2 was diagnosed with unilateral and P3 with bilateral CP. We monitored the early development of locomotor patterns over time via spatiotemporal gait parameters, intersegmental coordination , electromyography activity, and muscle synergies . P1 and P2 started to walk independently at the corrected age of 14 and 22 months, respectively. In both of them, spatiotemporal gait parameters, intersegmental coordination, muscle activation patterns, and muscle synergy structure changed from supported to independent walking, although to a lesser extent when unilateral CP was diagnosed (P2), especially for the most affected leg. The child with bilateral CP (P3) did not develop independent walking, and all the parameters did not change over time. Our exploratory longitudinal study revealed differences in maturation of locomotor patterns between children with divergent developmental trajectories. We succeeded in identifying mechanisms that may underlie impaired walking development in very young children at high risk of CP. When verified in larger sample sizes, our approach may be considered a means to improve prognosis and to pinpoint possible targets for early intervention. Cerebral palsy (CP) is a neurodevelopmental disorder caused by non-progressive brain lesions before birth or in the first year of life  children take their first independent steps (FS) between the age of 9 and 18 months, but this milestone is often delayed or not achieved in children with CP. Developmental stages of locomotion usually occur at a later age in children with CP compared to TD children . The study was approved by the Medical Ethics Committee of the Amsterdam UMC (location VUmc) (NL59589.029.16). The parents of all children were informed about the procedure of the study and provided written informed consent prior to participation in accordance with the declaration of Helsinki for medical research involving human participants.Experiments were performed in the clinical gait laboratory of the Department of Rehabilitation Medicine at the Amsterdam UMC, location VUmc. The laboratory setting and experimental procedures were adapted to the children, such that the risks were equal or lower to that of walking at home. The responsible investigators, one or both parents of the child, and a pediatric physiotherapist were present during the experiments.Every participant underwent five consecutive gait analysis sessions within a period of 1–2 years, to record development from supported walking (SW), to FS, to IW. SW sessions were conducted prior to IW onset. There, the pediatric physiotherapist, experimenter, or parent supported the child during stepping attempts by its trunk or arms. FS sessions were recorded when the children performed their first unsupported steps. They were scheduled within 2 weeks of first unaided walking experience, as reported by the parents. All sessions recorded after the FS session were labeled IW .All children walked barefoot on a treadmill during SW sessions and over ground during FS and IW sessions. If children wore ankle-foot orthoses in daily life, these were removed during the experiment. The treadmill speed was adjusted to induce a walking pattern and turned to a comfortable speed for the child. During FS and IW sessions, children were encouraged to walk in a straight line at a comfortable walking speed.During every session, full-body kinematics were recorded bilaterally and sampled at 100 Hz using a VICON system  with 12 cameras surrounding the 10-m-long walking area. Reflective markers (diameter 14 mm) were attached to the skin of the participants representative of anatomical reference points overlying the following bony landmarks on both sides of the body : glenohu2) were placed at the approximate location of the muscle belly on the cleaned skin, with interelectrode spacing of ~1.5 cm. EMG electrode placement was performed according to the Surface Electromyography for the Non-Invasive Assessment of Muscles protocol  from 11 pairs of bilateral leg and trunk muscles, i.e., tibialis anterior (TA), gastrocnemius medialis (GM), gastrocnemius lateralis (GL), soleus (SOL), rectus femoris (RF), vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF), tensor fascia latae (TFL), gluteus maximus (GLM), and erector spinae at L2 level (ES). Mini-golden reusable surface EMG disc–electrode pairs  kinematics: (a) spatiotemporal gait parameters, including walking velocity, stride duration, and double support duration; (b) intersegmental coordination, estimated via principal component analysis (PCA) of the elevation angles of thigh, shank, and foot segments  and duration of both legs. Data were time-interpolated over individual gait cycles to fit a normalized 201-point time base.t, αs, and αf, respectively) to correspond with angles between the segment projected on the sagittal plane and the vertical, i.e., to be positive in the forward direction when distal markers fell anterior to the proximal one. In healthy adults and older children, these elevation angles describe a path (gait loop) that lies close to a plane that is defined by their eigenvectors (1-PC3) including the explained variance (PV1-PV3) and eigenvectors (u1–u3), were obtained  and third (PV3) eigenvectors were assessed and compared between sessions, as well as the rotation of the normal to the plane by using the u3t parameter , full-wave rectified, and subsequently low-pass filtered (fourth-order Butterworth <10 Hz) to obtain linear envelopes. For some sessions, EMG data from few muscles had to be discarded because of sustained artifacts after filtering. Possible contamination of the EMG recordings could be detected by the electrical cross-talk due to volume conduction of activity across adjacent muscles. This issue is particularly relevant when recording many muscles in young children because of their small body size and the resulting close spacing of nearby muscles. Nevertheless, the small size of the EMG electrodes used in our settings and the chosen interelectrode distance should have minimized the pickup from adjacent muscles. Anyway, we attempt to quantify the potential electrical cross-talk by performing a cross-correlation analysis of selected pairs of adjacent flexor/extensor muscles. Cross-correlation was computed after notch (50 Hz) and high-pass (30 Hz) filtering the EMG data to remove any possible power line noise and movement artifacts. We identified the peak of the normalized cross-correlation >0.3 between flexors and extensors as suspect cross-talk . Non-negative matrix factorization (NMF) was applied to the unilateral gait-cycle averaged EMG envelopes to extract muscle synergies. NMF decomposes the EMG into EMG data  are a linear combination of the temporal activation patterns H  and synergy weights W (m × n matrix), and e denotes the residual error.where the preprocessed The reconstruction accuracy of the extracted synergies was determined by calculating the percent of VAF, which is the ratio of the sum of squared errors to the total sum of squares computed with respect to the mean . All data are reported as mean (±SD). Normality was assessed using Q–Q plots, and homogeneity of variance was tested using a Levene test. Development of spatiotemporal gait parameters, intersegmental coordination values, and FWHM per muscle across sessions within each participant was assessed using a linear mixed-effects model  was born at term after an uneventful pregnancy. Birth was complicated by umbilical cord entanglement and perinatal asphyxia with Apgar scores of 4 and 5, respectively, after 1 and 5 min, respectively. Clinically, she recovered quickly, and there was no indication for therapeutic hypothermia. Because of a possible infection, she was treated with antibiotics for 7 days, but blood cultures remained negative. Twenty-two hours after birth, she developed severe neonatal convulsions, for which the child was treated with phenobarbitone, midazolam, lidocaine, and levetiracetam. A magnetic resonance imaging (MRI) scan at the age of 4 days revealed extensive bilateral signal changes in the white matter of the frontal, temporal, parietal, and occipital lobes; corticospinal tracts; internal capsule; and thalamus. A probable diagnosis of hypoxic–ischemic encephalopathy due to perinatal asphyxia was made. Neurological examination at the age of 8 months showed a mild developmental delay and a mild paresis of the left arm. At follow-up, until the age of 3.5 years, development appeared normal, and no further abnormalities were found via neurological examination, excluding a diagnosis of CP.Child P2  was also born at term after an uneventful pregnancy. The child developed normally in the first 3 months of life, although it was noted that the right arm appeared stiffer when parents changed clothes. When 3 months old, asymmetry in upper extremity motor function was established. At the age of 5 months, he developed West syndrome for which he was successfully treated with levetiracetam and vigabatrin. Neurological examination at the age of 8 months showed spastic paresis of the right arm with hyperreflexia of the knee tendon reflex at the right side. An MRI scan of the brain at the age of 8 months showed a congenital infarction of the medial cerebral artery at the left side. A diagnosis of unilateral spastic CP, GMFCS I, was made.Child P3  was born preterm after 33 weeks and 1 day of pregnancy. At the age of 3 weeks, she suffered a group B streptococcal infection. She showed a developmental delay and rolled over for the first time at the corrected age of 11 months, and the tone of the lower extremities had been high since the first weeks. An MRI scan of the brain at the corrected age of 12 months showed periventricular leukomalacia, related to prematurity. A diagnosis of bilateral spastic CP, GMFCS III, was made.For P1 and P2, the sessions covered a period of 14.5 and 12.4 months in between the first and the last session and included one and two SW sessions, respectively, an FS session, and three and two IW sessions, respectively. For P3, the sessions covered a period of 24 months and included five SW sessions . P1 starVideo analysis revealed that P1 had a flat foot strike in sessions 1 and 2 , whereas both feet showed a heel strike from session 3 (IW) onward. P2 had a flat foot strike of both feet from sessions 2 to 4 , and during session 5 (IW), only the least affected leg showed a heel strike. P3 had a toe landing and was crossing her legs in all sessions.p < 0.001; P2, p < 0.001; P3, p < 0.01). For P1, a significant increase was found from SW session 1 to IW sessions 3 to 5 . For P1, a significant decrease was found between SW session 1 and all sessions . For P1, a significant decrease was found between SW session 1 and all sessions (p < 0.01). For P3, a significant decrease was between SW session 1 and SW sessions 3–4, but the percentage of relative stance duration increased again in session 5.The percentage of relative stance duration showed a significant main effect of session in all children  showed a significant main effect of session in P1 (p < 0.001), the least affected side of P2 (p < 0.01), and P3 (p < 0.001), but not in the most affected side of P2 (p = 0.110). For P1, a significant decrease was found between SW session 1 and all sessions, indicating a reduction in the width of the gait loop from SW to IW, which is also visible in the changes of gait loops for the IW sessions compared to the SW session (The percentage of variance accounted for by the second eigenvector (PV session . The lea3), which quantified the planarity of the gait loop, showed a significant main effect of session in P1 (p < 0.001), the most and least affected sides of P2  and P3 (p < 0.01). For P1, a significant decrease was found between SW session 1 and all sessions, indicating a reduction in the deviation from planarity  showed a significant main effect of session in P1 (p < 0.001), the most and least affected sides of P2  and P3 (p < 0.01). For P1, a significant increase was found between SW session 1 and FS session 2, whereas the most affected side of P2 showed a significant decrease between SW session 1 and IW sessions 4 to 5  in P2, indicating that these parameters developed differently over time for the most and least affected side.The orientation of the covariance plane . FWHM of TA, GM, SOL, RF, VL, BF, and ES significantly increased from SW session 1 to IW sessions 3 to 5, and of GLM from FS session 2 to IW sessions 4 to 5. In contrast, FWHM significantly decreased from FS session 2 to IW session 3 for TFL, and to sessions 3 to 4 for VM  and GL (p = 0.682) in the least affected side. In the most affected side, FWHM of TA, GM, GL, RF, BF, and TFL was significantly higher during IW sessions 4 to 5 compared to SW session 2, whereas FWHM of SOL, VM, VL, and ES already increased during FS session 3. In the least affected side of P2, FWHM of GM, VM, BF, and GLM significantly increased during IW sessions 4 to 5 compared to SW session 2, whereas FWHM of RF, TFL, and ES already increased during FS session 3. FWHM of SOL was only significantly larger during IW session 5 compared to SW session 1 (p < 0.01), indicating that FWHM of these muscles developed differently in the most compared to the least affected side.For P2, FWHM showed a significant main effect of session for all muscles in the most affected side, and for all muscles except TA (ession 1 . An intep < 0.05), except RF (p = 0.120). FWHM of TA, SOL, VM, BF, and TFL was significantly smaller in session 1 compared to all other sessions. FWHM of GM and GLM was significantly larger during sessions 4 to 5 and of GL during sessions 2, 3, and 5, compared to the first recorded session  of the Amsterdam UMC (location VUmc) (NL59589.029.16). Written informed consent to participate in this study was provided by the participants' legal guardian/next of kin.ABe, ABu, and ND designed the study. ABu and LvdP assisted in the recruitment of CP participants. ABe and ND carried out the measurements. ABe, MB, ABu, and ND performed the data analysis, and carried out drafting the manuscript. All the authors have read and concurred with the content in the final manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Communication between social learners can make a group collectively “wiser” than any individual, but conformist tendencies can also distort collective judgment. We asked whether intuitions about when communication is likely to improve or distort collective judgment could allow social learners to take advantage of the benefits of communication while minimizing the risks. In three experiments (n = 360), 7- to 10-year old children and adults decided whether to refer a question to a small group for discussion or “crowdsource” independent judgments from individual advisors. For problems affording the kind of ‘demonstrative’ reasoning that allows a group member to reliably correct errors made by even a majority, all ages preferred to consult the discussion group, even compared to a crowd ten times as large—consistent with past research suggesting that discussion groups regularly outperform even their best members for reasoning problems. In contrast, we observed a consistent developmental shift towards crowdsourcing independent judgments when reasoning by itself was insufficient to conclusively answer a question. Results suggest sophisticated intuitions about the nature of social influence and collective intelligence may guide our social learning strategies from early in development. Nevertheless, shared culture and cognitive biases can create illusions of consensus even without direct communication between individuals4. The empirical advantages of discussion and various crowdsourcing strategies are well-documented. Less attention has been given to laypeople’s own intuitions about the tradeoffs between them . Here, we investigate early developing intuitions about when group discussion or crowdsourcing is a more effective use of collective intelligence.When is advice from multiple people more likely to clarify than confound a learner’s understanding? Consider two ways one could learn from multiple people at once: by eliciting a consensus judgment from a small group discussion, or by “crowdsourcing” many independent answers. Discussion may enable groups to correct mistakes and combine insights, producing an accurate consensus answer that no individual could have found alone. However, without an objective method of evaluating solutions, discussion may drag on endlessly, be misled by charismatic leaders or groupthink, and ultimately only create an illusion of consensus around a wrong answer. In contrast, crowdsourcing may still include mistakes that discussion could have corrected, but particularly in 7, mathematical models suggest that under certain conditions, crowds can be “wise”. Given a set of options to “vote” for, majority and plurality accuracy increase to near certainty as crowd size increases9, and evolutionary simulations suggest that conformist learning strategies are often more adaptive than alternatives10. Similarly, averaging crowd members’ individual judgments can produce a collective estimate that is more accurate than the crowd’s most accurate member14. Interestingly, many species faced with the problem of learning from multiple sources at once rely on similar heuristics to evaluate collective opinion. Even in early childhood, people trust majority over minority judgment, and give more weight to stronger majorities15. By adulthood, people also trust pluralities, and give more weight to the judgments of larger crowds18.While debate over whether crowds can be trusted is at least as old as philosophy itself20. Yet, while popular concerns about echo chambers and media bias suggest that laypeople intuitively recognize some of the risks of social influences, it remains unclear how well people compensate for them in practice. For example, while adults and even children as young as six prefer firsthand knowledge over hearsay in an eyewitness memory context21, adults are just as trusting of an economic forecast repeated by five news articles citing a single primary source as they are of the same forecast citing five different primary sources22. Similarly, while children as young as four expect randomly sampled evidence to cause others to revise their beliefs more than evidence from a biased sampling process23, when the source of the sampling bias is the selection of informants itself, children are sometimes insensitive to bias even late in development—particularly when the degree of consensus is high29. Indeed, even as adults, people frequently mistake the frequency of a belief in their local networks for its frequency in the population as a whole32. In short, people’s trust and distrust of consensus seems to selectively disregard one of the proposed preconditions of consensus’ accuracy—independent sources.However, crowdsourcing heuristics share a common weakness: for crowds to be “wise”, individual judgments must be independent. Social influence can compound individual error, particularly when a large proportion of the population are conformist learnersmore accurate38. For instance, while open discussion may risk groupthink by sacrificing individuals’ independence, it also allows individuals to pool their knowledge and generate new insights; discussion can also ease the cognitive load on individuals, increase a groups’ capacity for processing information, and allow the group to correct individual mistakes41. This division of cognitive labor means that discussion groups may be able to quickly generate solutions that most individuals would never produce alone, and may make discussion an attractive learning strategy for a wide variety of problems, particularly as the evidence load increases45. Most notably, to the extent that discussion enables even a single group member to correct a majority that has made a mistake, discussion may also have an advantage over crowdsourcing heuristics like majority rule46. Studies of group problem-solving have suggested that this ‘truth wins’ effect occurs when a shared conceptual system enables individuals to conclusively demonstrate that a given answer is correct or incorrect—and it is the strength of their argument, rather than the individual’s confidence or simply the presentation of the correct answer, which predicts whether the majority will be persuaded. Importantly, these studies suggest that “demonstrability” is a matter of degree, ranging from mathematics as the “preeminent domain of demonstrability” to purely judgmental tasks such as attitudes and preferences, with a variety of evidence-based reasoning and insight problems also being high in “demonstrability”49. Note the implication of the “truth wins” effect for social learners: if a minority is able to demonstrate that their judgment is accurate, the majority is not simply influenced by the judgment of the minority, they will defer to it. Thus, when demonstrations are possible, discussion groups may offer substantially more accurate collective judgments than a “crowdsourced” majority, with little risk of distorting an accurate majority judgment. Indeed, recent accounts suggest that reasoning itself may be most naturally deployed in service of argumentation and function most effectively in interpersonal contexts51.One reason for people’s occasional indifference to their sources’ independence may be that social influence frequently makes their judgments only beneficial for questions that afford demonstrative reasoning, or that demonstration and reasoning are synonymous. Rather, we focus on discussion and crowdsourcing as flexible, commonsense approaches to a fundamental problem for any social learner: integrating information from multiple sources without inheriting their errors. Our intent is to examine laypeople’s intuitions about their tradeoffs. Though crowdsourcing heuristics like majority rule can be remarkably accurate, they also presuppose independent judges—an unrealistic assumption about human societies. Meanwhile, work on group problem-solving has repeatedly found that discussion not only allows groups to outperform heuristics like majority rule, but that their ability to do so depends on the “demonstrability” of the problem57. Of course, demonstration is possible without reasoning , and reasoning cannot always conclusively demonstrate a that a solution is optimal. However, reasoning may be a reliable means of correcting errors even when physical demonstrations are not feasible, and when a correct answer cannot be simply deduced. For example, knowing the distance from New York to Chicago won’t allow a group to deduce the distance from New York to Cleveland, but it may enable them correct some over- and underestimates without needing to actually measure the distance. Indeed, in a recent comparison of group discussion with the wisdom of crowds on a numerical estimation task, the average collective estimate of four small-group discussions was more accurate than the average of 1400 individual estimates, and participants reported arriving at their estimates by “sharing arguments and reasoning together”53. In short, to the extent that people expect to be able to rely on demonstrative reasoning to minimize the risks groupthink, it may be intuitive to disregard the importance of independent judgment, even if they favor crowdsourcing heuristics in other cases.Note that we are not claiming that group discussion is 26, we focused on adults and children ages 7–10. Understanding how the ability to balance the risks and benefits of social influence develops could shed light on the incongruence of our remarkable capacity for collective problem-solving and our apparent susceptibility to groupthink. It may also provide clues as to where interventions to thwart misinformation may be most effective.In the present work, we asked whether people would favor different social learning strategies for problems that afford demonstrative reasoning than those that do not. Crowdsourcing independent judgments may be more valuable when the potential for reasoning is less salient, particularly when the crowd is large. Discussion may be more valuable when demonstrative reasoning provides a reliable means of analyzing problems and identifying errors, even if the discussion group is small. Because past work suggests that sophisticated social learning strategies emerge in early childhood but also that children appear to underestimate some risks of social influence even in late childhoodReasoning and 4 Non-Reasoning), and for each question, they rated whether crowdsourcing or discussion would be more helpful in answering, on a 4-point scale. In Experiment 1, this meant that participants rated whether it would be more helpful to ask five people to each answer independently, or to ask the same five people to give a single group answer after discussing. In Experiments 2 and 3, we contrasted the five-person group discussion with a crowd of 50 people answering alone. For the Reasoning questions, we chose a set of constraint-satisfaction problems that would challenge adults’ capacities, but still be understandable to children . Because the solutions to these questions must satisfy a mutually understood set of explicit constraints, discussion can help groups generate potential solutions and and reduce processing demands on individuals while relying on demonstrative reasoning to correct errors. In Experiments 1 and 2, we contrasted the Reasoning questions with Population Preference questions . Though individuals’ intuitions may sway as the discussion generates potential answers, discussion provides no objective means of adjudicating disagreement; thus, it may distort intuitions rather than sharpen them. In Experiment 3, we contrasted easy versions of the same Reasoning questions with a set of challenging Perceptual Discrimination questions , which a separate sample had rated as more difficult than the Reasoning questions. This allowed us to test the role of perceived difficulty against the potential for effective reasoning. If participants simply favor discussion for questions that feel more difficult—regardless of whether discussion can reliably adjudicate disagreement—then the preference for group discussion will be stronger for the Perceptual Discrimination questions than the Reasoning questions. Our general prediction in all three experiments was that sensitivity to the contrast between reasoning and intuitive judgment would lead all ages to prefer group discussion for reasoning questions. However, because past work has suggested that children may underestimate the risks of social influence until between the ages of 6 and 926, we predicted that a robust preference for crowdsourcing non-reasoning questions would emerge only among older children (ages 9–10) and adults, while younger children (ages 7–8) would favor group discussion for both kinds of questions in Experiments 1 and 3. All experiments were preregistered, and the data, materials, and power analyses (https://osf.io/6pw5n/) are available on the OSF repository. All experiments were approved by the Yale University Institutional Review Board and conducted according to their guidelines. Written informed consent was obtained from all adult participants. Because children participated online, parents were recorded reading the informed consent form aloud.In each experiment Fig. , partici54. Sample size was chosen based on the estimated effect size from pilot results. We recruited 40 adults through MTurk, as well as 80 children . Children participated through an online platform for developmental research that allows researchers to video chat with families using pictures and videos on slidesReasoning and Popularity. Questions were presented from the perspective of a protagonist (Jack). The Reasoning questions were chosen to be simple enough to explain to children, but challenging enough that the answer would not be immediately obvious to adults. (1) A 4 × 4 Sudoku puzzle adapted for children. (2) A vehicle routing problem that required a MarioKart character to find the shortest road through all the treasures on a map without taking “two in a row that are the same color, or two in a row that are the same shape”. (3) A single-heap game of Nim . (4) An “impossible object” puzzle that requires the solver to remove a dowel held in place by a nut and bolt from inside a bottle without breaking the dowel or the bottle. The Popularity questions concerned the most common subjective preferences in a population. (1) Whether pizza or hot dogs were more preferred by students in Jack’s school. (2) What most people in the world say their favorite fruit is. (3) What most people in the world say their favorite day is. (4) What most people at Jack’s school say their favourite color is. Questions were written to have approximately equal word counts . Three counterbalances were created to vary the order of the questions—Forward, Reverse, and a Shuffle. Color coding of answer choice and left/right presentation were also counterbalanced between participants. We asked eight test questions Fig. , four frTalking Together (giving Jack a single answer as a group), or by Answering Alone (each giving Jack their own answer after thinking about the question without consulting others). For each item, children and adults rated whether “talking together” or “answering alone” was “probably more helpful, or definitely more helpful”, producing a 4-point scale of relative preference, where 1 corresponds to “definitely answering alone”, and 4 corresponds to “definitely talking together.” Adults used the scale directly; children’s responses were staggered: they first chose the more helpful strategy, and then were asked for a “probably/definitely” judgment. After answering the eight test items, participants were asked the two comprehension check questions . Two features of the procedure are important to keep in mind. First, participants could not evaluate the content of any answer to any question, because none was given: they were asked to choose a means of advice, not evaluate the quality of the advice itself. Secondly, they could not make judgments based on degree or quality of consensus—they only knew that the group would have to give one answer, while the crowd would have to give 5 independent answers which could differ or not. Children were introduced to the protagonist, Jack (a silhouette). They were told that Jack was unsure of the answers to the questions, and could ask five people for help. The five people could either help by Type  = 132.87, p < 0.001, ηp2 = 0.532) and an AgeGroup*Type interaction  = 7.83, p < 0.001, ηp2 = 0.118), and a marginal but non-significant effect of AgeGroup  = 2.82, p = 0.064, ηp2 = 0.046). Multiple comparisons suggested that intuitions about how to manage collective wisdom appear by at least age 7: consistent with the empirical literature suggesting that group reasoning outperforms individual reasoning, all age groups believed that Talking Together would be more helpful than Answering Alone for Reasoning questions, both as compared to Popularity questions  = 3.66 p = 0.0057, Older: t(117) = 7.105, p < 0.0001, Adult: t(117) = 9.201, p < 0.0001), and compared to chance  = 7.42, p < 0.0001, Older: M = 3.19, SD = 0.51, t(39) = 8.53, p < 0.0001, Adult: M = 3.45, SD = 0.54, t(39) = 11.237, p < 0.0001). Moreover, both Older children and Adults favored Answering Alone over Talking Together for Popularity questions, though Younger children’s answers for Popularity did not differ significantly from chance  =  − 0.232, p = n.s., Older: M = 1.94, SD = 0.86, t(39) =  − 4.076, p < 0.001, Adult: M = 1.83, SD = 0.81, t(39) =  − 5.24, p < 0.0001). The preference for group reasoning did not differ by age , though Older children and Adults showed a stronger preference for crowdsourcing Popularity questions than Younger children (Bonferroni corrected: Adult vs. Older: t(78) = 0.718, p = ns; Adult vs. Younger: t(78) = 4.067, p < 0.001; Older versus Younger: t(78) = 3.350, p < 0.0143). This developmental shift towards Answering Alone when discussion provides no objective criteria for evaluating accuracy is slightly earlier than we had predicted, but consistent with past work on children’s evaluation of non-independent testimony26. For the primary test, the four responses within each question domain Fig. a were avTalk Together, while a teacher who wanted to know which students had done their homework should have the students Answer Alone . This suggests that by age 7, children recognize that discussion could undermine inferences about individuals’ “independent” beliefs, but expect group discussion to either generate or disseminate accurate answers.Finally, all ages agreed that a teacher who wanted a group of five students to answer test questions accurately should have the students Taken together, these two tasks suggest that sophisticated intuitions about the risks and benefits of social influence may guide decisions about how to learn from collective judgment. Notably, these intuitions are consistent with empirical findings documenting the a group advantage over individuals for reasoning questions, and the value of independent responding when discussion is likely to bias collective judgment.Popularity questions simply ask the group or crowd to estimate what most people in a population prefer, all age groups would find it intuitive to ask more people—i.e., the crowd. The benefit of large crowds is less clear for Reasoning questions. If few individuals can solve a problem alone, identifying the correct answer in the crowd may be akin to finding a needle in a haystack; indeed, if individual accuracy is known to be rare, the most common answer may be a widely-shared misconception53. Yet, if many individuals can solve the problem alone, large crowds are redundant and a learner can outsource evaluating accuracy to a group discussion. We therefore predicted that adults and older children would continue to favor group deliberation over crowdsourcing for Reasoning questions. However, we saw two plausible alternatives for younger children. First, younger children could show the mature pattern. Alternatively, younger children’s preference for reasoning in groups could be attenuated by a “more is better” bias. Additionally, since the only difference between Experiments 1 and 2 was the increased crowd size, our design also allows us to explore the effects of crowd size itself by comparing the two experiments directly.Could Experiment 1 have underestimated the value of crowdsourcing? Crowdsourcing may be most valuable with large crowds: larger crowds are more likely to include at least one accurate individual, and better represent the relative frequency of beliefs in the population. Moreover, in large enough crowds, even a minimal plurality will easily outnumber the unanimous consensus of a small group. Thus, if a belief’s frequency is a cue to its accuracy, a large crowd will always be more informative than a small group. In Experiment 2, we contrasted the 5-person group with a larger 50-person crowd. We predicted that since the 53. One additional child was excluded and replaced because the family lost internet connection partway through the experiment and could not rejoin.We recruited 40 adults through MTurk, as well as 80 children . As in Experiment 1, children participated through an online platform for developmental research that allows researchers to video chat with families using pictures and videos on slidesAnswering Alone instead of five. The materials and procedure were identical to Experiment 1, but participants were first shown a large crowd of people, and told that Jack could either ask 5 of them to Talk Together, or 50 of them to Answer Alone. The answer choices from Experiment 1 were altered to display fifty cartoon icons for Type  = 376.88, p < 0.001, ηp2 = 0.763) and AgeGroup  = 9.63, p < 0.001 ηp2 = 0.141), and an AgeGroup*Type interaction  = 5.39, p < 0.01, ηp2 = 0.084). Despite the crowd having ten times as many sources as the group, participants were not swayed by a “more is better” bias; all age groups continued to prefer the group discussion for Reasoning questions, both as compared to Popularity questions  = 8.60 p < 0.0001, Older: t(117) = 11.97, p < 0.0001, Adult: t(117) = 13.06, p < 0.0001), and compared to chance responding  = 9.29, p < 0.0001, Older: M = 3.28, SD = 0.42, t(39) = 11.75, p < 0.0001, Adult: M = 3.15, SD = 0.65, t(39) = 6.37, p < 0.0001). Moreover, even younger children in Experiment 2 favoured Answering Alone for Popularity questions, suggesting that they recognized that a large crowd would provide a better estimate of population preferences than a small group  =  − 3.38, p = 0.0017, Older: M = 1.57, SD = 0.69, t(39) =  − 8.52, p < 0.0001, Adult: M = 1.28, SD = 0.66, t(39) =  − 11.75, p < 0.0001). As in Experiment 1, the preference for group reasoning did not differ by age , though Older children and Adults again showed a stronger preference for crowdsourcing Popularity questions than Younger children  = 1.995, p = ns; Adult versus Younger: t(78) = 5.334, p < 0.001; Older vs. Younger: t(78) = 3.339, p < 0.0147). We also conducted two exploratory analyses of the effect of crowd size. Our preregistered prediction in Experiment 2 was that participants would favor the crowd for population preference questions, but continue to favor the group for reasoning questions. However, because the only difference between Experiments 1 and 2 was the increase in crowd size from 5 to 50 people, our data also enables us to test the crowd-size effect directly. We ran separate ANOVAs for each QuestionType using AgeGroup & Experiment as predictors. The tenfold increase in crowd size had no impact on participants’ preference for discussing Reasoning questions in small groups  = 0.045, p = 0.8320); an AgeGroup*ExpNum interaction was significant  = 4.434, p = 0.0129), but post-hoc comparisons revealed only a marginal difference between younger children’s and adults’ preferences for reasoning in groups in Exp 1, with no other differences. However, participants were significantly more likely to crowdsource Popularity questions in Experiment 2 than Experiment 1  = 19.303, p < 0.0001), with no differences between age groups. As before, the four responses for each question ype Fig. b were avYoung = 67.5%, p = 0.019, MOld = 92.5%, p < 0.0001, MAdult = 90%, p < 0.0001). However, while older children and adults agreed that the students would do better on the test if they could discuss their answers, younger children were at chance . Younger children may be less confident in the value of discussion than their responses to the main task questions in Experiments 1 and 2 would suggest; however, informal questioning of participants after the experiment suggested that younger children in Exp 2 may have simply rejected talking together on a test as cheating, even though the question specified that the teacher could choose to allow students to talk together.As in Experiment 1, responses to the comprehension questions at the end of the task suggested even the youngest children recognized that talking together would make it impossible for the teacher to know which students had done their homework . As in Experiments 1 & 2, children participated through our online platformPopularity questions with four Percept questions: (1) decide which of two pictures of a face “at the tipping point of animacy” is a photo and which is a photorealistic drawing60, (2) decide whether an opaque box contains 30 or 40 marbles by listening to a recording of it being shaken61, (3) identify which of twelve colored squares in a visual array is rotating the fastest, and (4) rank the 25 brightest stars in a photo of the night sky in order of brightness. Second, we simplified the four Reasoning questions  cType. A repeated measures ANOVA again revealed a significant effect of question Type  = 56.12, p < 0.0001, ηp2 = 0.324) and AgeGroup  = 7.01, p = 0.0012, ηp2 = 0.108) an AgeGroup*Type interaction  = 4.40, p = 0.0143, ηp2 = 0.070). The perceived difficulty of the questions had no discernible effect on participant judgments: participants of all ages again rejected the large crowd in favor of the small group discussion for the Easy Reasoning questions  = 5.35, p < 0.0001, Older: M = 3.22, SD = 0.51, t(39) = 8.97, p < 0.0001, Adult: M = 2.95, SD = 0.78, t(39) = 3.64, p = 0.0008). We also observed the predicted developmental shift towards Answering Alone when reasoning was insufficient to answer the question; however, in Experiment 3 the shift occurred later than expected instead of earlier. While Adults favored Answering Alone and Younger children favored Talking Together for the Hard Percept questions as predicted, Older children did not show the adult pattern, instead not differing from chance for Hard Percept  = 2.66 p = 0.011; Older: M = 2.44, SD = 0.71, t(117) = -0.55, p = 0.7535; Adult: M = 2.11, SD = 0.69, t(117) =  − 3.62, p = 0.0008). Moreover, while Older children and Adults distinguished between the two question Types, Younger children did not  =  − 1.91 p = 0.8701, Older: t(117) =  − 5.318, p < 0.0001, Adult: t(117) = 5.74, p = 0.0001). As in Experiments 1 and 2, the preference for group reasoning did not differ by age , though Younger children showed a weaker preference than Adults for crowdsourcing Percept questions  = 2.156, p = ns; Adult vs. Younger: t(78) = 4.516, p < 0.0002; Older vs. Younger: t(78) = 2.360, p = ns). Indeed, while participants of all ages were just as confident in the small group discussion for Easy Reasoning questions in Experiment 3 as they were for Reasoning questions in Experiment 2, all ages were less confident in polling a crowd of 50 for Hard Percept questions in Experiment 3 than for Population Preferences in Experiment 2 , at age ten children are still no more likely to diagnose in-group favoritism as an influence on judgments in subjective contexts than objective contexts63. In our experiments, both the reasoning and non-reasoning questions had objective answers, but only the reasoning questions afforded an objective method of finding those answers. Learning to recognize this relatively subtle distinction may allow children to take advantage of the benefits of group discussion while avoiding the risks. This is not to suggest that people expect group reasoning to be infallible—merely that they expect groups to improve individual accuracy. This is consistent with recent work asking adults to predict group and individual accuracy on a classic reasoning task: while participants radically underestimated the true group advantage, they did expect groups to be more accurate than individuals64. Interestingly, they also expected dyads to be less accurate than individuals. A more granular approach to intuitive beliefs about the dynamics of social influence may reveal more sophisticated intuitions: for instance, beliefs about others’ conformist tendencies and the distribution of individual competence may increase confidence that “truth wins” in small groups more than in dyads.Analogously to young children’s failures on false belief tasks, our results suggest that the default expectation for group judgments may be that “truth wins”: though individuals may initially disagree, discussion allows groups to ultimately see the truth. As an understanding of how conscious and unconscious biases can influence people’s judgments develops, learners can preempt potential biases by crowdsourcing independent judgments. Though even the youngest children in our experiments expected discussion to improve accuracy on reasoning questions, the preference for crowdsourcing non-reasoning questions underwent a developmental shift in all three experiments. Indeed, in Experiment 3, the youngest children favored discussion for both kinds of questions, suggesting that they may have failed to recognize when discussion can promote groupthink. The timing of the developmental shift is consistent with past work suggesting that between the ages of 6 and 9, children begin to use informational dependencies65, they defer to others more when uncertainty is high and crowds are larger67. While increasing the crowd size from five to fifty had no impact on Reasoning questions in our experiments, the larger crowd did appear to increase crowdsourcing for Population Preference questions. However, while we only tested Hard Percept questions with a crowd of fifty, confidence in crowdsourcing was lower for Hard Percept questions than for Population Preferences (can improve accuracy69. Thus, participants’ reduced confidence in crowdsourcing Hard Percept questions may have been justified. The extent to which intuitive beliefs about the benefits of discussion and crowdsourcing for different question types correspond to the empirical benefits is an open question.Past work has suggested that while people dramatically underestimate crowds and overestimate their own accuracyferences . While o67. However, the meaning of dissent may vary across contexts and questions. In a crowd, a single “dissenter” may simply have made a mistake; but dissent-despite-discussion signals that the group has failed to convince them. When questions afford conclusive demonstrations of accuracy, failure to convince all discussants may reflect poorly on group accuracy. Conversely, in more ambiguous contexts, unanimity may suggest groupthink. For instance, in ancient Judea, crimes more likely to elicit widespread condemnation were tried by larger juries for the express purpose of reducing the odds of consensus, and unanimous convictions were thrown out on the grounds that a lack of dissent indicated a faulty process—an intuitive inference confirmed by modern statistical techniques70. A similar logic may underlie inferences about testimony that contradicts social alliances. For example, if Jenny says Jill is bad at soccer, even preschoolers give Jenny’s judgment more credence if Jenny and Jill are friends than if they are enemies63. Our results suggest that even in early childhood, the absolute number of sources endorsing a belief may be less important than how those sources arrived at their beliefs. Indeed, the limited number of possible answers to the questions in Experiments 2 and 3 guaranteed that even a plurality of the 50-person crowd would considerably outnumber the 5-person group. Yet, participants’ preference for discussion and crowdsourcing bore no relationship to the number of possible endorsers. Future work will compare explicit degrees of consensus in groups and crowds.Our design is limited in one important respect: the discussion group was only allowed to give a single answer, while the crowd could give multiple answers. This procedure strictly ensured that group members could not answer independently, but also entailed a unanimous consensus endorsed by a minimum of five people. Unanimous consensus can be a powerful cue: even a single dissenter can sharply reduce conformity73. By focusing on population-level outcomes, much of this work has tacitly treated individuals as passive prisoners of social influence. However, the heuristics guiding social learning develop in early childhood, and recent work has shown that like other intelligent systems capable of self-organization, people are capable of “rewiring” their social networks to improve both individual and collective learning, by “following” or “unfollowing” connections depending on their accuracy73. Our experiments focused on two features of communication patterns that individuals can and do control in the real world, beyond who they choose to trust: how many people to talk to, and whether to talk with those people as a group or a crowd. Our results suggest that even in early childhood, people’s judgments about how to best make use of group discussion and crowdsourcing heuristics may be consistent with the empirical advantages of each strategy. An understanding of how intuitions about social influence develop may contribute to a clearer empirical picture of how people balance the benefits of learning from collective opinion with the risks of being misled by it.The last decade has produced an extensive literature describing how individual social learning heuristics and patterns of communication in social networks can improve or diminish collective learningSupplementary Information.


The adsorption of molecules usually increases capacity and/or strength with the doping of surfaces with transition metals; furthermore, carbon nanostructures, i.e., graphene, carbon nanotubes, fullerenes, graphdiyne, etc., have a large specific area for gas adsorption. This review focuses on the reports  of systems using these structures decorated with transition metals for mainly pollutant molecules’ adsorption. Furthermore, we aim to present the expanding application of nanomaterials on environmental problems, mainly over the last 10 years. We found a wide range of pollutant molecules investigated for adsorption in carbon nanostructures, including greenhouse gases, anticancer drugs, and chemical warfare agents, among many more. Since their discovery in 1985, the study of fullerenes and their exciting properties led to the subsequent discovery of many other carbon nanoforms: nanotubes, carbon onions, graphene, graphdiyne, carbon nanotori, etc., including hybrid nanostructures ,3,4,5,6,2, N2O, CH4, and many others is urgent. CO comes mainly from the non-complete combustion of fuels that contain carbon, and it is toxic and an asphyxiant. On the other hand, plenty of industrial processes in our world generate greenhouse gases like CO2, N2O, and CH4. Thus, humankind’s climate change and ecological challenges have increased the interest in carbon nanostructures for fast green applications 2O) and c60 fullerenes can adsorb H2, and their interaction has been studied by several means, including a modification of the L-J potential and the continuum approach [60 fullerenes oxidize at 400 °C and a pressure of 2 bar, they enhance their surface and increase H2 adsorption. Experimental studies showed that this process increases the H2 adsorption by a factor of three, at 77 K and a pressure of 120 bar [60 or C70 fullerenes are doping helium droplets, they can physisorb both hydrogen H2 and deuterium D2 [460 fullerene would reach H2 storage of 7.60 wt% at 300 K.Such pristine Capproach . When C6 120 bar . When C6erium D2 , the aut16N16 fullerene-like form would have low conductivity and reactivity compared with the fullerene C32 and a B-doped fullerene labeled as B8C24. They concluded that the B16N16 system was the most suitable H2 adsorbent of these three cases.There are theoretical investigations to compare the efficiency of the porous structure of fullerenes with that of similar hexagonal boron nitride (hBN) nanocages. In , the aut2) molecules by different fullerenes such as sphere-like C82 or the tubelike C110. The interaction between N2 and such fullerenes can lead to (N2)n molecular clusters [2 molecules can be better adsorbed by a C60 fullerene when the latter is B-, N-, or BN-codoped. The best adsorption performance is obtained with the BN-codoped C60 fullerene, labeled as C58BN, and obtained after doping by substitution of two carbon atoms by nitrogen and boron atoms [Other theoretical calculations using DFT show the adsorption of nitrogen gas , a highly toxic and dangerous gas, is an example of this, as DFT calculations have shown that a C20 fullerene can adsorb it. Doping the fullerene with either boron or nitrogen affects its interaction with Tabun, showing that the B-doped fullerene, or C19B, is better to detect the hazardous gas, due to a larger change of the system’s electrical conductivity [The detection and sensing of chemical warfare agents (CWAs) is a research line where fullerenes play a relevant role. The tabun nerve agent (Cuctivity .2N2) is another toxic gas that fullerenes could detect. DFT/B3LYP calculations show that OH-functionalizing or Ge-doping of C60 fullerene result in a larger adsorption capacity than a pristine C60 fullerene, although the increase is relatively small [60 fullerenes can adsorb the amphetamine (AA) drug. Additionally, DFT calculations show that the AA-C60 interaction increases the fullerene by substituting C atoms with either Si or Ge atoms. In both cases, the AA drug tends to be adsorbed at the  bonds of the C60 structure, i.e., the bonds joining two hexagons in the fullerene structure [Cyanogen  obtained employing a thermal decomposition of polyethylene terephthalate (PET) bottles  is an excellent candidate to purify dye-contaminated wastewater . Table 32 and does it more quickly than CO adsorption [2 efficiently [Graphdiyne—in some works abbreviated as GDY—is a recently developed 2D material that has raised interest because it is a metal-free catalyst for low-temperature CO oxidation. It is helpful to absorb CO molecules. According to spin-polarized DFT calculations, graphdiyne can also absorb Osorption . Howevericiently .3OH) are physisorbed by the pristine GDY surface, while a Ca-decorated graphdiyne (Ca-GDY) can further increase their adsorption. Ca-GDY can adsorb up to 29.81 wt% of CH3OH and 27.10 wt% of CO.In , the autA GDY monolayer also adsorbs atomic oxygen and hydrogen at different sites. Hydrogen chemisorbs above a carbon atom and oxygen at the hollow place. According to such studies, oxygenated graphdiyne could be useful for spintronic devices .5H9NO4), histidine (C6H9N3O2), and phenylalanine (C9H11NO2). MD simulations at room temperature suggest that graphdiyne adsorbs such amino acids with an energy more significant than that on graphene, with dispersion interactions predominating in the process [Graphdiyne is helpful to detect amino acids, such as glycine (C₂H₅NO₂), glutamic acid (C process . Graphdi process .21H16ClF3N4O3) and regorafenib (C21H15ClF4N4O3) then release them upon protonation [Other studies show that graphdiyne is a helpful drug delivery agent for medical applications. DFT and Quantum-Monte-Carlo simulations suggest that GDY adsorb the drugs sorafenib (Ctonation .3) according to ab initio calculations, showing a better adsorption capacity than graphdiyne nanotubes [Graphdiyne sheets adsorb ammonia molecules  results from bonding hydrogen to three of the C atoms in a benzene ring, facilitating nitrogen doping . HsGDY a and NO2 . Boron d and NO2 . The 5-f and NO2 .2 molecule, while the B, N, O, Si, P, and S-decorated GDY chemisorbed it [Besides boron, other nonmetal atoms like Si, P, S, As, Se, and Te are used through DFT calculations to decorate graphdiyne surfaces to increase their ability to dissociate molecular oxygen. The As- Se- and Te-decorated GDY monolayers physisorbed the Oorbed it .2 molecules while investigating the possible conversion of CO2 into beneficial—or at least less nocive—chemicals via carbon dioxide electrochemical reduction reaction (CO2RR) [Li, an alkali metal, is another exciting option. The authors in ,96 showe (CO2RR) .2RR improved with nitrogen doping on graphdiyne (NGDY), increasing the selectivity regarding the doping with CH3OH and CH4. In particular, the lowest limiting potential of CH3OH on NGDY gets reduced. Further composites such as boron- and nitrogen-doped GDY anchoring a single Cu atom (labeled as Cu@N- and Cu@B-doped GDY) have also been systematically explored via ab initio calculations. The result is that Cu@N-doped GDY monolayers are more efficient than the boron-doped ones for CO2 reduction and highly catalytic activity toward CO2RR [In , the autrd CO2RR .2, and ammonia (NH3) [2 to sp3 caused by the introduction of N atoms [However, there are cases where boron-doped GDY shows a better performance than nitrogen-doped GDY, as demonstrated by spin-polarized DFT studies. For instance, B-GDY shows excellent sensitivity and selectivity toward NO, NOia (NH3) . Recentl N atoms .Improving catalysis can be seen the other way around: instead of decorating graphene sheets, they could be the decoration. For instance, when placed on the Pt(111) surface, a graphdiyne layer gives better results at increasing the latter two-dimensional confined catalysis performance compared with graphene or hexagonal boron nitride .1, L2 and L3 with the highest GDY sensitivity being found to be towards L2 [Finally, an increasing interest in the effective detection of chemical warfare agents (CWAs) has led to the investigation of graphdiyne as a possible sensor. Using ⍵B97XD DFT and Quantum theory of atoms in molecule (QTAIM) analysis, studies in  found thwards L2 . Table 4176. The results show that the adsorption energies ranged between 0.069 and 0.115 eV. Up to four hydrogen molecules could get into the C176 [We define a hybrid system as the surface created using different carbon nanostructures, i.e., the combination of graphene or graphdiyne with nanotubes or fullerenes or semi fullerenes or buckybowls. The result is a set of structures with a larger specific area for gas adsorption purposes. For instance, theoretical investigations use DFT focused on the hydrogen adsorption on a system made of graphene decorated with Cthe C176 .Another frequently investigated structure for gas adsorption is pillared graphene, which comprises graphene sheets joined by carbon nanotubes. In , the aut4) adsorption on Pillared graphene. They found that in this case, the CNT length has the most significant effect on the adsorption amount of methane among different geometrical parameters such as CNT diameter, graphene sheet layer spacing, and the number of CNTs. The adsorption ability of pillared graphene is greater than that of graphene sheets. Such a structure has higher mechanical stability than graphene.Using a hybrid molecular dynamics–Monte Carlo simulation method, the authors in  investig180, C320, and C540. Hence, this would be a potentially helpful system for hydrogen storage.A variation of the pillared graphene system considers fullerenes instead of nanotubes placed between the graphene sheets. In , the aut4) adsorption. These structures are labeled as Sandwiched Graphene-Fullerene Composite (SGFC) and have a promising potential for methane storage applications. This Li-doped nanostructure could be considered suitable host materials for lightweight methane storage devices [180, C320, and C540. It was observed that a Li-doped nanostructure with a doping ratio of Li:C = 1:8 can overpass the gravimetric capacity of 5%, while an undoped one can reach the value of 3.83% at 77 K and 1 bar. The Li-doped SGFC capacity is larger than that observed in graphene-based systems [Other studies involving grand canonical Monte Carlo simulations considered fullerenes placed between graphene sheets and lithium doping to investigate methane (CH devices . The sam systems .Carbon nano onions (CNO) are another interesting mixed nanostructure discovered in 1992. These systems are multi-shell fullerenes with concentric shells of carbon atoms with an interlayer distance similar to graphite . Experim2, CH4, and C2H2. Studies using hybrid DFT calculations found that the curvature of the buckybowl surface plays a significant role in the adsorption of these gas molecules. Buckybowls are high-performance materials for capturing greenhouse gases, molecular recognition, and nanotechnology applications in general [To finish this section, we will focus on buckybowls. A buckybowl is not a hybrid system, but an interesting one nevertheless. These structures come from the fragmentation of fullerenes. Buckybowls are adsorbents of CO general . Hybrid The definition of transition metals usually refers to those elements in groups 3–12 on the periodic table, with partially filled d-orbitals. The frequent name for the lanthanide and actinide series is inner transition metals. However, it is more frequent to call transition metals the elements of groups 4–11. This fact relies on the typical chemical behavior of the metals in these groups. Note that the filling of the d-orbitals increases going from left to right in the periodic table. It is usual to name them the “d-block elements.” Thus, these metals have several properties in common. First, they have low ionization energies, and several of them form paramagnetic compounds. Second, these metals are reactive but not as much as the alkalis. Finally, they conduct heat and electricity very well and have high melting and boiling temperatures.3H6O (acetone), C6H6 (benzene), H2, CH4, NH3, NO2, H2O, CO, H2S, HCN, HCl, Cl2. Specifically, Pd used for the adsorption of H2, Cl, CH4, Cl2, acetone, benzene; Pt used for the adsorption of C7H8 (toluene), H2, NO2, H2O, NH2; Au for the adsorption of C2H6O (ethanol), NH3, NO2, and Rh used for the adsorption of HCl, CO, and CH4. Furthermore, doping with Fe makes adsorption of the hydrogen molecule stronger than on an undoped nanotube. The adsorption of Fe on the nanotube is exothermic [Doping nanotubes to increase their adsorption capacity is frequent. In particular, the decoration involving transition metals, oxides, or polymers, can increase their sensitivity . It is aothermic .2 storage capacity of pristine MWCNTs increases up to 15 times at room temperature and 2.0 MPa by decorating them with ultrafine Ti nanoparticles. This improvement does not affect the cyclic hydrogenation–dehydrogenation operation of the tubes [2 adsorption, probably due to the strong interaction between the Ni atoms and the MWNTs [Experimental studies found that the Hhe tubes . The inthe MWNTs .2S, CO, and SO2 [2 and H2S [3H6O) gas, with the Au decoration increasing the device sensitivity up to around 3% at room temperature [DFT calculations of Pt-decorated nanotubes show different effects in the adsorption capacities of the latter. For instance, the nanotube conductivity can vary with the adsorption of H and SO2 . Another and H2S . These Aperature .2H4 (ethylene), and SO2 molecules while proving to be insensitive to CO2 and CH4 [2 and H2S molecules by the Ru-doped SWNT.Rh-doped single-walled carbon nanotubes are advantageous for the adsorption of CO, C and CH4 . DFT cal and CH4  showed tPd and Pt decorations on a nanotube are practical to adsorb CO and NO molecules. Pd decoration is more suitable to adsorb NO, while Pt works better for CO adsorption. Ab initio calculations showed that this adsorption would change the magnetic properties of the Pd- and Pt-decorated SWCNTs, which would be helpful for sensors .2O on the otherwise inert nanotube [2 and O3 and show relatively significant conductivity changes [Pd as a dopant facilitates the adsorption of Nnanotube . More DF changes . There i changes .2 decoration of nanoparticles on graphene oxide (GO + Ti) can adsorb twice as much H2 as pristine graphene at room temperature and 5 MPa, showing reversibility of up to 80% [2 adsorption. In [2 adsorption performance, with a promising reversible cycle.We label TM-doped graphene the graphene doped with transition metals in this review. As with the other nanostructures considered in this review, hydrogen adsorption is a heavily explored topic, and transition metal-doped graphene has been no exception. For instance, a TiOp to 80% . Copper-tion. In , a DFT s2), a highly toxic CWA [TM-doped graphene has been considered a possible candidate to sense different polluting gases, which usually interact weakly with pristine graphene. We have the chemical warfare agents (CWAs) among the pollutant gases under investigation, mentioned in oxic CWA .2H2, CH4, and CO, which are characteristic dissolved gases in transformer oil. In [4 is weak due to an electronic hybridization.Other DFT studies suggest that Mn-doped graphene substantially improves the adsorption of C oil. In , the aut2S) that is another toxic and colorless gas. DFT studies show that Cu-doped graphene and DG display the best performance to adsorb H2S among the cases considered. Ni and Zn-doped graphene show weaker adsorption energies. Other studies show that Pt-decorated graphene is an H2S detector. The most stable configuration for adsorption corresponds to the H atoms of the H2S pointing towards the TM-doped graphene [2S, and this adsorption increases by doping (BG) with transition metals as Fe, Ni, Mn, Cr, Co, and V. Notice that the TM-doping can occur at more sites concerning a single graphene layer, for example, in the interlayer region.TM-doped graphene with TM = Ni, Cu, Zn, or Ni-doped vacancy defect graphene (DG) and graphene oxide (G-OH) adsorb hydrogen sulfide  is also increased mainly by combined doping of Cu and Zn atoms, the resulting system labeled as Cu/Zn-ZGNR, with a high response value of around 49% [DFT calculations also show that an external electric field would further increase the adsorption of H devices . Additioound 49% .3), another toxic gas. As in previous cases, TM doping increases the chemical interaction with the gas compared with pristine graphene. In [3/CO selectivity, an important feature when removing arsine from CO gas streams. The resulting hybridization of states between AsH3, CO, and TM orbitals confirmed the chemical interaction.TM-doped graphene  adsorbs arsine  are candidates for NO and NO2 sensing devices due to their electronic and transport properties [Recent theoretical investigations utilizing DFT considered Ag- Pt- and Au-doped graphene as a possible sensing material of nitrogen oxides such as NO and NOAl, or S . In [151operties .2 [Group 10 transition metals such as Ni, Pd and Pt can also decorate graphene to increase its interactions with NO2  signific2 .13 structure, when supported on pristine graphene, can also enhance the adsorption capacity of the latter. A systematic DFT study showed that such a composite could adsorb CO2, NO2, and SO2 more effectively than defective graphene (DG) supported Pt13 [Platinum clusters like the Ptted Pt13 .2 can be adsorbed more efficiently by metal-oxide such as ZnO, BeO, and Ni-decorated graphene than pristine graphene. ZnO- and BeO-decorated graphene physisorb SO2, while Ni-decorated graphene chemisorbs it [The latter gas, sulfur dioxide, has also been the subject of experimental and theoretical studies involving TM-decorated graphene. SOsorbs it .TM-doped graphene can also enhance the detection of formaldehyde (HCHO) gas. A first-principles study considered a two-probe sensor device built with TM-doped graphene, where TM = Co, Ni, Cu, Zn, Pd, and Ag. The Cu- and Ag-doped graphene devices showed the best performance at low voltages, with a short response time and high HCHO sensing . Table 860 fullerene, with TM = Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn. The changes in the electronic structure implied that the TM-decorated C60 fullerene is more sensitive to CO and NO molecules than the pristine one.The TM-doping or decoration increases the adsorption capacities of fullerenes. This increase by doping is present in the other carbon nanostructures reviewed in this work. In , the aut2 storage capacity. A way of doing it is by substituting carbon atoms with titanium atoms and doping a C60 fullerene with an increasing number of Ti atoms, from one up to six. With six Ti atoms doping C60 fullerenes in this fashion—labeled as Ti6C48—the hydrogen storage can be up to 7.7 wt% [60 fullerene labeled as C60Con, chemisorb an H2 molecule, with different features for different values of n (n = 1 to 8). They also found that up to 13 H2 molecules could be absorbed in this way.Doping fullerenes with titanium increases their H 7.7 wt% . In [15770 fullerene doped with TM ions (Cr2+ and Co2+) adsorbed nitrogen dioxide (NO2) on the exterior surface. The doping mechanism is a porphyrin-induced process labeled as PIC70F. In this manner, this fullerene would be helpful for selective detection of NO2 in the presence of sulfur dioxide, also showing a short recovery time.Theoretical calculations performed in  showed t60 fullerenes are considered, the EMFs obtained in this manner are labeled as Mn@C60, and they can increase the oxygen reduction reaction (ORR) activities of the former. A comprehensive DFT study showed that EMFs such as Mn5@C60, Cu4@C60, Co2@C60, and Ni4@C60 have better ORR activities, which could be helpful in developing sensing devices able to detect polluting gases [Another way of doping fullerenes is from the inside, an example of which would be the endohedral metallofullerenes (EMFs). Such structures are obtained by putting a lowest energy structure of a metal cluster inside of the fullerene and then relaxing the system. When Cng gases . Table 9Transition metals (TMs) can enhance the adsorption properties of graphdiyne (GDY). Several DFT studies have explored the adsorption of metals like Au, Cu, Ni, and Zn—although Zn is not a transition metal—on graphdiyne. GDY strongly chemisorbs nickel, and it also chemisorbs silver and copper. On the other hand, graphdiyne physisorbs a zinc atom. Overall, this material is better adsorbent for those metals compared with graphene . When th2 adsorption capabilities, aiming at reversible hydrogen storage. DFT studies have considered decorating graphdiyne nanosheets with light metals such as Li, Na, K, Ca, Sc and Ti. Some works have explored up to 11% of metal functionalization in the GDY surface, which can then anchor multiple H2 molecules [As with the other nanostructures covered in this review, graphdiyne has been explored for its Holecules .Water splitting is another exciting application of TM-decorated GDY nanosheets. For instance, theoretical simulations and experimental studies show that Ru-doped GDY (Ru/GDY) has a high catalytic performance for oxygen evolution reactions .2 at room temperature is relevant for the production of ammonia (NH3). A systematic study considering transition-metal-embedded GDY, or TM@GDY, explored the effect of Sc, Fe,Cr, Mn, Mo,Co, Ni, Cu, Zn, Ru, Rh, Pd, and Ag in the N2 reduction reaction. According to spin-polarized DFT simulations, the most stable and best catalytic activity was the Mo-embedded graphdiyne monolayer [2 reduction reaction (NRR) character. However, other studies indicate that the single-atom catalyst V@GDY monolayer has the best NRR performance [The electrochemical reduction of Nonolayer . All TMsformance .2@GDY) [Anchoring two transition metals to GDY improves the NRR activity. In a study involving DFT calculations, the authors considered several TMs . They found that the best NRR performance was with the Co-Ni heteronuclear complex (CoNi@GDY) and the Mo-Mo homonuclear complex (Mo2@GDY) .Scandium and titanium can also decorate graphdiyne to enhance sensing of formaldehyde (HCHO), a typical air pollutant. Sc or Ti take a stable place on the corner sites of graphdiyne sheets, and both can better adsorb HCHO compared with pristine graphdiyne and graphene. This effect would be due to the electronegativity of HCHO, and the best result is with Ti-decorated graphdiyne, according to DFT calculations .2O2 to produce O2, an essential reaction in antitumor treatments combined with doxorubicin, a chemotherapeutic agent [In , the autic agent .2 by GDY sheets. An ab initio study found that doping the GDY surface with a Fe dimer or a Fe trimer optimizes the CO2 adsorption and selectivity. The number of Fe atoms considered can generally tune the GDY catalytic activity significantly [Doping GDY with Fe atoms improves the electrochemical reduction of COficantly . CO oxidficantly . Table 1+, and cations as Li+, Na+, K+, to buckybowls on convenient locations where the gradient electron density favors the adsorption [0.64Ni0.36@CNOs > Fe3C@CNOs. The Ni@CNOs have a maximum hydrogen storage capacity of 1.42%. Large amounts of defects, good electrical conductivity, and electrocatalytic activity of the Ni particles are responsible for their excellent electrochemical performance [Several studies have also focused on the TM-doping of hybrid carbon nanostructures starting. The most convenient places to dope a buckybowl have been studied by computational means, covering the binding possibilities of the transition-metal ion Cusorption . In otheformance .30 with titanium to adsorb molecules of CO and CO2. With an exploration involving density functional theory (DFT) and first-principles molecular dynamics (FPMD) at 300 K and atmospheric pressure, they found that the most stable adsorption of the titanium atom on C30 occurs on the concave surface of the molecule. Besides, the considered molecules are chemisorbed, with no dissociation. The adsorption energies depend on the initial orientation of the molecules concerning TiC30. Similarly, in [2 molecule in a system formed by a graphene layer and a Ti-doped semi-fullerene. The authors found that the semi-fullerene is bound to the graphene layer, with one of the hexagonal faces of the former being oriented into the latter. Besides, the semi-fullerene chemisorbs the titanium atom. Finally, the authors studied the interaction between the hydrogen molecule and the combined system, finding that the system can adsorb the H2 molecule. In , the autarly, in , densityWe aimed to present the most important and recent advances in the study of polluting gas adsorption employing carbon nanostructures. The porous nature of the latter has made them a natural choice for developing sensing devices throughout the years, and physical features like diameter, curvature or size, influence their adsorption capabilities. The carbon nanostructures reviewed in general physically adsorb many of the pollutant gas molecules considered, and the interaction can usually increase by different means of nonmetal functionalizations or doping. However, transition-metal doping and decoration give better results overall, increasing their sensing properties, involving chemisorption in most cases studied. There have also been many systems showing a good adsorption–desorption cyclic performance, which makes them good candidates for sensing devices.Among the transition metals used as dopants in the reviewed works, we found Ag, Au, Pt, Pd, Fe, Rh, Zr, Mo, Ti, Mn, Co, Ni, Cu, Sc, and V. Besides, we found the non-transition metals as dopants too: Zn, Si, P, S, As, Se, Te, Li, N, and B.2, NH3, NH2, SO2, H2S, C2H6O, C3H6O, C7H8, NO, Cl2, CH4, N2O, CO, C2H4, CO2, O3, CH3OH, H2CO. H2CO2, C2H2, SF6, C2N2, C6H14, C7H8, C2H3N, CH2Cl2 CH3COOC2H5, (CH3)2NH, C3H9N, AsH3. Moreover, the anticancer drugs 5-fluorouracil and temozolomide. We also found amphetamines. Finally, we also found the chemical warfare agents (CWAs) tabun, sarin, soman, cyclosarin, phosgene, and Lewisite molecules.On the other hand, among the pollutant molecules investigated for adsorption in carbon nanostructures that we found in this review, we have NOCarbon nanotubes and graphene are probably the most investigated systems, as shown by the abundance of cites. However, the detailed study of its adsorption properties is ongoing.To end, we should mention that the study of the adsorption properties of carbon nanostructures is far from being completed. Relatively recent structures like graphdiyne have plenty of potential applications waiting for the investigation, and the building of hybrid systems has much to offer for materials scientists in the future.


The tensile, thermal, and the antimicrobial properties of the films were studied. The results revealed that the irradiated films exhibited improved functional properties compared to the control film at 1.5 kGy radiation dosage. The tensile strength, tensile modulus, and toughness exhibited by the films increased, while the elongation of the irradiated bio-composite film decreased compared to the control film. The morphology of the irradiated films demonstrated a smoother surface compared to the control and provided surface intermolecular interaction of the neem–seaweed matrix. The film indicated an optimum storage stability under ambient conditions and demonstrated no significant changes in the visual appearance. However, an increase in the moisture content was exhibited by the film, and the hydrophobic properties was retained until nine months of the storage period. The study of the films antimicrobial activities against Staphylococcus aureus (SA), and Bacillus subtilis (BS) indicated improved resistance to bacterial activities after the incorporation of neem leaves extract and gamma irradiation. The fabricated irradiated seaweed–neem bio-composite film could be used as an excellent sustainable packaging material due to its effective storage stability.Antimicrobial irradiated seaweed–neem biocomposite films were synthesized in this study. The storage functional properties of the films were investigated. Characterization of the prepared films was conducted using SEM, FT-IR, contact angle, and antimicrobial test. The macroscopic and microscopic including the analysis of the functional group and the gas chromatography-mass spectrometry test revealed the main active constituents present in the neem extract, which was used an essential component of the fabricated films. Neem leaves’ extracts with 5%  The Synthetic petroleum-based polymers have been widely utilized as packaging materials due to their relative abundance including their good mechanical and thermal properties . Over thHowever, the challenge of poor mechanical properties and high water barrier permeability is a major drawback that limits their application for packaging. Seaweed, which is a natural macromolecular biopolymer, has the capacity to be developed as films . Its intAscophyllum nodosum for the improvement of the physico-chemical and antioxidant properties of gelatin and sodium caseinate biofilms. Neem leaves have provided improved antimicrobial activities in biofilms as suitable additives to enhance the properties in order to ensure food safety towards sustainable packaging applications. Neem leave extracts have received a remarkable amount of interest due to their composition of phenolic compounds that enables strong antimicrobial activities; they also exhibit high anti-bacterial activity against Gram-positive bacteria in food borne pathogens [The isolation of MCC from bamboo precursor has been utilized as reinforcement material in seaweed composite films . The useathogens . The long-term stability of functional properties of films is essential during storage to ensure the quality of the stored products. Packaging under this condition has the potential to protect stored products against discoloration, deterioration, pathogenic activities, and textural changes. However, a sustainable approach to maintain the stability and functional properties of film packaging bio-materials is a major concern during storage . The incThe neem leaves were harvested from Bukit Mertajam, Penang. Macrolagae red seaweed was purchased from Green Leaf Synergy Sdn. Bhd Tawau Sabah, Malaysia. 95% pure ethanol of vapour density 1.59, boiling point 78.3 °C, and density of 0.789 g/mL was purchased from Sigma Aldrich . In addition, the glycerol  used in the study was supplied by Sigma-Aldrich . The fully matured Azadirachta indica (neem) leaves were collected and washed under running tap water to remove any dirt prior to the drying process. The leaves were air dried for 20 days, then ground into a powder and stored in airtight bottles. Ethanol was used for the isolation of the neem leaves extract from its leaves as described by  with sliAzadirachta indica leave extracts was investigated to examine the physical properties of the extracts. Prior to the investigation, the leaf tissues were immersed in 10% buffered formalin. After that, the tissues were dehydrated using different percent concentrations of alcohol  and were later cleared in xylene and embedded in paraffin wax. Lastly, 5 mm cross-sections of the blocks were mounted on slides and stained with 0.5% methylene blue and were examined under a light microscope [The preparation of the samples for microscopic investigation of the anatomical sections were carried out according to the methods described by  with modcroscope .−1 to 4000 cm−1 and the infrared spectra were recorded in transmittance mode. The functional properties of the neem leaves extracts was examined using the Fourier transform infrared (FTIR) spectroscopy . The powdered Azadirachta indica leaves were mixed with potassium bromide (KBr) salt, using mortar and pestle, and were compressed into a thin pellet. The leaves extract was treated for FT-IR analysis with a scan range—from 500 cmv/v), and then filtered. The particle-free diluted neem leaves extract (1 μL) were obtained in a syringe and injected into injector with split mode at a split ratio of 1:120. The percentage composition of the neem leaves extract constituents was expressed in terms of percentage peak area. The chemical compounds were identified and characterized in the crude extract based on GC retention time. Gas chromatography–mass spectrometry (GC–MS) analysis was conducted on the neem leaves crude extract using Shimadzu GC–MS-QP2010 Ultra GC–MS for the identification of the phytoconstituents. The leaves’ extracts were analyzed in paste form using the methods of  with sliw/v) seaweed was dissolved in 300 mL distilled water and stirred continously for 15 min after which 1.8 g of glycerol was added to 50 w/w % seaweed and was homogenously stirred for 25 min. In addition, 5% w/w neem leaves extract was added to the seaweed film structure, based on our previous work on the incorporation of different neem leaves extract in the seaweed-based film [About 6 g . The tensile tester was used for the analysis using UvWin1000 software , and test samples were characterized according to ASTM D882-12 [on), the maximum temperature (Tmax) of decomposition and the (%) residual were determined from the temperature profile from the TGA curve. The residue was expressed as the residual after weight loss at 800 °C.The functional properties of seaweed, seaweed–neem and gamma-irradiated seaweed–neem films were investigated. FT-IR analysis was conducted on the films. The samples were oven-dried at 60 °C for 24 h before analysis. The samples were analyzed using the FT-IR spectroscopy within the wavelength of 500 and 4000 cm D882-12  standardThe seaweed–neem gamma irradiated film with 1.5 KGy was used for this study. The film was tightly packed in a plastic container and sealed. The packaged samples were stored at temperature of 25 ± 2 °C and at a relative humidity of 50 ± 5% RH for two years. The packaging materials were analyzed to study the effect of moisture content, water barrier properties and antimicrobial analysis. The film was used as the control for determining the stability of the film at 0 day of storage. wW) and dried weight (dW) as follows: Moisture absorption capacity of the irradiated films were investigated at different intervals of storage period . The percent moisture content of the films was examined at room temperature in the desiccators and at controlled RH using silica gel. The test samples were weighed under a controlled chamber at temperature and RH of 25 ± 2 °C and 50 ± 5%, respectively. The films were fully dried and weighed after which they were put in plastics and placed in the desiccator. The films were weighed again at intervals of the predetermined storage period. The percent moisture content was evaluated from the measured wet weight  15EC, Filderstadt, Germany. The irradiated films were cut to 1 cm × 1 cm dimension and properly placed on a flat edge that is attached to the contact angle analyser. In addition, 3 µL droplets of deionized water were placed on the surface of the film. Average contact angle from measurements taken from 10 different positions of the film were recorded. The test samples were conditioned at 50% RH before measurements were taken. The color analysis of the irradiated film during the storage period was conducted using a colorimeter spectrophotometer, Hunter Associates Laboratory, Inc., Reston, VA, USA. The values of ∆E for the analysis of color changes exhibited by the irradiated film were evaluated according to . The valStaphylococcus aureus and Bacillus subtilis. The diameter of the inhibition zone measured in millimeters was obtained using a caliper. All analyses were conducted in triplicate. The analysis was carried out on day 0 at 3-month intervals until 24 months were completed. Three replicate samples were prepared for each storage day. Antimicrobial analysis was carried out at 37 °C for 24 h on a 6 mm disk diameter films using agar diffusion assay and pathogens Azadirachta indica leaves indicated fresh and matured neem leaves with unequally pinnate, shiny, and dark glossy green at maturity. The average length of the leaves was within 20 to 40 cm long. The cross section of the leaflets were 3 to 8 cm long, 1.2 to 4 cm width with noticeable sickle-shaped, slightly denticulate, petiolate, and asymmetric base with a dark green color on the upper surface and lighter green color on the lower surface [Azadirachta indica leaf revealed the presence of the upper and lower epidermis, vascular tissues (xylem and phloem), mesophyll with palisade layer, parenchyma cells, and collenchyma cells. The upper epidermis consists of polygonal, slightly axially elongated cells with straight anticlinal walls, covered with slightly striated and thick cuticle with lower number of stomata. The structure of the lower epidermis consists of axially elongated cells with slightly wavy anticlinal walls which were covered with faintly striated cuticle and anomocytic stomata. Furthermore, the vascular bundles in the midrib region were arranged in two crescent-shaped groups forming an almost continuous ring. The observed structures of the leaf were comparable to [The surface properties of the neem leave extract used for the fabrication of film are illustrated in  surface . The petrable to .The ethanol crude extract of neem leaves was analyzed using GC–MS and fragmentation patterns of the mass spectra were compared with those of the known compounds stored in the Chemstation Data System. The percent chemical composition of the constituents of the ethanol crude extracts is presented in −1 is attributed to stretching vibration of the O–H functional group for an intramolecular hydrogen bond or a phenolic group of neem leaves. The strong stretching band is also attributed to the presence of N–H stretching and bending vibration of amine group NH2. The absorption peak at 2924 cm−1 corresponds to C–H stretching vibration modes in the hydrocarbon chains, while the band corresponding to the stretching vibrations of the carbonyl functional group in ketones, aldehydes, and carboxylic acids were assigned at 1734 cm−1 [−1 is attributed to the amide C=O stretching indicating the presence of –COOH group in the neem leaves and the peak at 1384 cm−1 corresponds to stretching vibrations that originated from the C–H stretching, CH2 wagging, C=O, and C–O bonds of acetyl esters, respectively. The positions of the aliphatic C–C were found at 1249 cm–1, and the band at 1070 cm−1 in powdered neem leaves was assigned to C–O stretching vibration.The FT-IR spectra of the neem leaves powder are shown in 734 cm−1 . The abs−1 was assigned to the presence of the O–H groups, which decreased as the neem was incorporated into the seaweed film. The peak also decreased as the irradiated dosage of the films was increased compared to the control film. The absorbance from 3000 to 2900 cm−1 and peaks from 1500 to 1700 cm−1 were attributed to C–H and C=O stretching vibration, respectively, which indicated no significant difference relative to the control film. Similar results have been reported in previous studies [−1 were due to the carboxyl group (C=O) which are attributed to the stretching of carboxyl groups in the sulfated polysaccharides of seaweed. A strong band appeared at 1000 to 1220 cm−1 for the raw seaweed, which increased as irradiation dosage of the films increased. The assigned peak was attributed to the sulfate ester-stretching of the seaweed backbone [−1 could be attributed to the polysaccharide glycosidic linkage stretching vibration suggesting that irradiation of the films did not alter the interfacial interaction between the neem extract in the seaweed matrix [−1 is assigned to C–O and C=CH2 stretching vibrations of pyranose rings. These functional groups are very commonly present in all polysaccharides. The peaks at 923.90 cm−1 were due to the presence of 3,6-anhydro-d-galactose, and peaks at 844.82 cm−1 were assigned to d-galactose-4-sulphate [−1 is assigned to the skeleton bending of pyranose ring in seaweed [The surface functional properties of seaweed (SW), seaweed–neem (SWN), and seaweed–neem gamma irradiated films (SWN0.5–2.0) are shown in  studies . The peabackbone . Increasbackbone . The strd matrix . The peasulphate . This pa seaweed .w/w % into the control seaweed films resulted in a moderate enhancement in tensile strength of the control seaweed films from 36.2 MPa to 40.0 MPa. The increase in the tensile strength observed in the seaweed–neem film indicated good dispersibility as a result of the interaction of the hydroxyl groups in the matrix [The tensile properties of seaweed, seaweed–neem, and seaweed–neem gamma irradiated film at 0.5, 1, 1.5, and 2 kGy are presented in e matrix ,42. Howee matrix . It coulw/w neem leaves extract in the seaweed film increased the EB to 19.4%. The incorporation of the neem leaf extract could possibly increase the interfacial bonding interaction within the matrix [The elongation at break (EB) of the control seaweed film, seaweed–neem extract film, and the irradiated seaweed–neem films are represented in e matrix . The ince matrix . Moreovee matrix . The rade matrix , suggestw/w neem leaves extract concentration in which the voids were reduced compared to the control film. The fractured surface was rough with closed pores due to the incorporation of neem leaves extract in the seaweed matrix, which further improved the pore structure, morphology, and alignment of the fracture surface. The addition of neem extracts in the seaweed matrix improved the surface roughness compared to the control seaweed film, indicating clear changes in the morphological features due to the improved interfacial bonding as a result of the compatibility of the neem–seaweed matrix. This could be due to the formation of strong intermolecular interaction between seaweed and neem leave extract [The SEM images were obtained to analyze the fracture morphology of the seaweed, seaweed–neem, and seaweed–neem gamma irradiated film as presented in  extract . The sig extract  on the fHowever, the SEM micrographs of the irradiated seaweed–neem film c revealeon), which is the point, the film began to disintegrate where deflection on the TGA curve was observed. The maximum temperature of degradation (Tmax) of the seaweed film was shifted to a higher temperature after the incorporation of neem leaves extract at 5 w/w % suggesting that the incorporation of neem leaves improved the thermal stability of the seaweed-based film [on and Tmax. Moreover, the increase of thermal degradation temperature was also due to the presence of glycerol as a dispersing agent that could promote better seaweed–neem interactions [on) and the (Tmax) was shifted to a higher temperature after the gamma radiation treatment on the seaweed–neem composite film optimally at 1.5 kGy at 273.5 and 262 °C. Further increase in radiation treatment by 2.0 kGy resulted in a decrease in the degradation temperature and percent residue of the film by 251.21 °C and 30.2%, respectively. These findings were in good agreement with a previously reported study by [Thermal properties of the seaweed based films were studied using Thermogravimetric analysis (TGA) to investigate the decomposition and thermal stability of the films . It was sed film . This coractions . The charactions  indicatiractions . The effstudy by , and it The percent moisture content of the control film and irradiated film measured at room temperature and 50% RH is presented in The effect of storage time on the properties of the ISN films as packaging material were evaluated at ambient conditions (25 °C with 50% RH). The effect of storage time on the tensile properties of the packaging film such as tensile strength (TS), tensile modulus (TM), and elongation at break (EAB) were shown in Findings indicated that the TS and TM decreased as the storage time increased. As compared to the control film, the storage period of 24 months exhibited the lowest TS and TM. Conversely, the EB increased as the storage time increased. The highest EB was achieved at 24 months of storage. However, a steep decrease in TS and TM of the developed ISN film as storage time increased demonstrated that the storage stability of the irradiated films within 24 months was not significantly affected by the storage period, even though a slight steady decrease in the tensile films’ tensile strength was achieved as EAB increased . The TS The application of biopolymer films has proven to be a suitable alternative to conventional plastics for active packaging. However, in this study, the possible mechanistic action of the irradiated antimicrobial films is illustrated in Staphylococcus aureus, and Bacillus subtilis is indicated in w/w neem leaves extract into the control film demonstrated inhibitory activities against Staphylococcus aureus and Bacillus subtilis with the diameter of inhibition zone of 12.61 ± 0.27 mm and 8.92 ± 1.09 mm, respectively [The antimicrobial activities of the films were measured using the agar diffusion method with film in a disc shape. The diameter of inhibitory zones surrounding the film discs was used to evaluate the inhibitory and antimicrobial activities of the irradiated films . The antectively , suggestectively . In addiectively . This coectively . Staphylococcus aureus and Bacillus subtilis until a radiation dosage of 1.5 kGy was applied. It can be inferred that an increase in irradiation dosage significantly enhanced the antimicrobial activities of the films against Staphylococcus aureus compared to Bacillus subtilis. Similarly, the irradiation of the films resulted in the induced free radicals in the film as a result of increased bonding interactions between neem extracts in the seaweed matrix in the film structure, thereby enhancing the antimicrobial activity of the film [However, the irradiation of the seaweed–neem films at different dosages exhibited increased inhibitory zones against the film .Staphylococcus aureus and Bacillus subtilis. This result was in good agreement with a previous study on polyamide coated low density polyethylene (LDPE) film with active compounds , where the antimicrobial activity of the films was found to get retained when exposed to 1–3 kGy [Although the films exhibited a less inhibitory effect against the investigated bacteria after an irradiation dosage of 2 kGy was applied compared to the effect of other irradiation dosage without a significant negative effect. These suggested that the interfacial interaction of the neem extracts in the seaweed matrix and subsequently the effect of irradiation of the films enhanced antimicrobial activities against  1–3 kGy .Staphylococcus aureus (S. aureus) and Bacillus subtilis (B. subtilis) was investigated for 24 months using optimal irradiation dosage of 1.5 kGy as shown in S. aureus and 22.05 mm against B. subtilis. The extent of inhibition of microbial activities slightly decreased after 24 months of storage compared to the effect of microbial activities before storage. The values of the inhibition zone achieved for S. aureus and B. subtilis were 10.03 mm and 18.78 mm, respectively. It was clearly evident that a slight decrease in the inhibition zone at 24 months of storage compared to six months of storage indicated that the ISN film exhibited stability against microbial activities during storage despite the prolonged storage period, suggesting that the antimicrobial effect of the film could be attributed to the relatively high concentration of ethyl. Alpha-d-glucopyranoside, ethyl 9, 12, 15-octadecatrienoate, and phytol compounds [S. aureus and B. subtilis over a prolonged storage period as evidenced in enhanced antimicrobial activities even after a 24-month storage period. The stability of ISN film at storage conditions of 25 °C with 50% RH against ompounds , which wompounds  reportedompounds , which iw/w neem leaves extract and were treated with an optimized radiation dosage of 1.5 kGy gamma radiation. The irradiated films exhibited enhanced tensile properties and thermal stability of the film with excellent antimicrobial activity towards Staphylococcus aureus and Bacillus subtilis, which is significant for effective storage for packaging. The irradiated films demonstrated reduced water permeability, suggesting improved hydrophobic properties. The morphology of the irradiated composite film indicated a well aligned smoother surface compared to the control seaweed–neem film. This can be attributed to the improved tensile properties of the irradiated films as a result of good intermolecular interaction of neem extracts in the seaweed matrix. During the storage period, the film exhibited an optimum storage stability and indicated no significant changes in the physical appearance. The film revealed optimum enhanced tensile properties, which is an indication of improved mechanical properties exhibited by the film. The inhibition of microbial activities slightly decreased after irradiation of 2 kGy, compared to the effect of microbial activities of the control film, and the decrease did not affect the antimicrobial activities of the film. Accordingly, the stability of the irradiated film during prolonged storage period indicated the suitability of film for sustainable food packaging with enhanced antimicrobial activities. This study successfully fabricated an antimicrobial seaweed–neem extract irradiated film. The films were characterized and storage functional properties of the films were investigated for sustainable packaging application. The seaweed-based films were incorporated with 5%