An elicited imitation task was administered to L2 learners at beginner, intermediate and advanced Chinese proficiency levels. L1 influence is not observed at beginner levels, but it appears at intermediate and advanced levels, L1 influence disappears at different time in English and Korean learners’ oral production of verb-ellipsis and ΣP-ellipsis. It is proposed that the absence of L1 influence at beginner levels is due to a breakdown of syntax-stylistics interface and beginners’ difficulty in implementing checking and deleting operations in their L2 oral production. The different timings of the disappearance of L1 influence in the two language groups at advanced levels is attributed to interactions between the persistence of L1 influence and the computational complexity involved in the target elliptical structures.The article reports on an empirical study investigating the role of L1 at the initial and developmental stages of L2 speech production. It examines two types of Chinese verb- phrase-ellipsis, ΣP-ellipsis licensed by the auxiliary  Specifically, unlike English wh-questions, where a wh-word is required to be raised from its base-generated position to the initial position of a sentence, a wh-word in Chinese wh-questions remains in situ. However, his study finds no evidence in the results that wh-movement in English is transferred into L1 English learners’ L2 Chinese wh-questions and causes problem in this aspect of their L2 Chinese grammars. Also, Chinese and English share the same restriction on attitude-bearing wh-questions, which regulates that a question cannot have more than one attitude. Yuan’s study shows that English speakers are unable to rule out ungrammatical Chinese wh-questions with two attitude features embedded in them, indicating that the similarities between English and Chinese in attitude-bearing wh-questions have very limited facilitation to L1 English learners’ handling of L2 Chinese wh-questions with more than one attitude feature. On the basis of It is widely observed that in contrast to the uniform success of children acquiring their first language (L1), few adult learners can achieve native-like competence in their acquisition of a second language (L2). Obviously, L2 learners already have a language, i.e., their L1, in their mind, which can exert influence on their L2 acquisition. FTFA, , 1996 prThe present study is an attempt to track the role of L1 in L2 speech production at different stages of L2 development. It aims to examine whether L1 grammar is transferred to L2 oral production at initial stages of L2 development, as predicted by the FT Hypothesis FTFA, , 1996, hThe article is structured as follows. Section “Cross-linguistic differences of verb-phrase ellipsis in Chinese, Korean and English” discusses syntactic analyses of verb-phrase ellipsis in Chinese, English and Korean, and Section “Prior studies of L1 influence on L2 oral production” briefly reviews prior studies on the L2 production of Chinese elliptical structures and outlines the research questions. Section “Present study” introduces the methodology of the present study, and Section “Results” reports the scoring methods and results. The results are discussed in Sections “Discussion” and “Conclusion” contains our conclusions.shi是 “BE”, as exemplified in (1), and a verb-phrase ellipsis licensed by auxiliaries other than shi “BE”, as illustrated in (2). As noted in shi ‘BE’ is larger than that licensed by the other auxiliaries like hui 会 ‘will’. As shown in the contrast between (1) and (2), the elided constituent in the latter includes the verb phrase likai yingguo “leave the UK”, whereas that in the former includes the auxiliary hui ‘will’ as well as the verb phrase likai yingguo ‘leave the UK’. Also, as can be seen in the contrast between (3) and (4), when containing the negator bu 不 ‘not’ in the antecedent clause, the scope of ellipsis licensed by shi ‘BE’, as shown in (3), includes the negator bu ‘not’, but that licensed by the auxiliary hui ‘will’ does not, as shown in (4).Chinese allows two types of verb-phrase ellipsis: a verb-phrase ellipsis licensed by the auxiliary 会 离开 英国。1. 张三 会 离开 英国， 李四 也 是 hui likai yingguo.Zhangsan hui likai yingguo, Lisi ye shi Zhangsan will leave the UK Lisi also BE will leave the UK.‘Zhangsan will leave the UK, and Lisi will (leave the UK) too.’离开 英国。2. 张三 会 离开 英国， 李四 也 会 likai yingguo.Zhangsan hui likai yingguo, Lisi ye hui Zhangsan will leave the UK Lisi also will leave the UK.‘Zhangsan will leave the UK, and Lisi will (leave the UK) too.’不 会 离开 英国。3. 张三 不 会 离开 英国， 李四 也 是 bu hui likai yingguo.Zhangsan bu. hui likai yingguo, Lisi ye shi Zhangsan not will leave the UK Lisi also BE not will leave the UK.‘Zhangsan will leave the UK, and Lisi will (leave the UK) too.’离开 英国。4. 张三 不 会 离开 英国， 李四 也 不 会 likai yingguo.Zhangsan bu. hui likai yingguo, Lisi ye bu hui Zhangsan not will leave the UK Lisi also not will leave the UK.‘Zhangsan will not leave the UK, and Lisi will not (leave the UK) either.’shi ‘BE’, a dummy auxiliary in Chinese, occupies the head of TP, a position higher than the other auxiliaries such as hui ‘will’ in the hierarchy. Following hui ‘will’ are generated under a Mod node, which is lower than T, where shi ‘BE’ is located. The positions of the auxiliary shi ‘BE’ and the other auxiliaries in the hierarchy in hui ‘will’ occupy the head of ModP, lower than the category Σ, which can be realized by the negator bu ‘not’ to express negative meaning; in contrast, shi ‘BE’ occupies the head of TP, which is higher than ΣP.Based on the above observations, the present study follows shi ‘BE’ and the other auxiliaries occupy different structural positions implies that they also differ in terms of the constituent they license. Thus, in line with shi ‘BE’ is a ΣP, whilst that licensed by the other auxiliaries like hui ‘will’ is a vP.The fact that cf.According to It should be noted that complete sentences without verb-phrase ellipsis, as shown in (5), are perfectly grammatical in Chinese. However, they are stylistically heavy and unconcise, and thus are less preferred than the elliptical counterparts. Then, combining the above facts, we assume that in the derivation of a sentence with verb-phrase ellipsis, the deletion of the vP or ΣP is triggered at the syntax-stylistics interface, on the premise that the verbal identity condition is met.5. 张三 会 离开 英国， 李四 也 会 离开 英国。Zhangsan hui likai yingguo, Lisi ye hui likai yingguo.Zhangsan will leave the UK Lisi also will leave the UK.‘Zhangsan will leave the UK, and Lisi will leave the UK too.’will and can  and (4) respectively. Here we adopt will in (6), is also a vP.It is widely observed that English allows its verb-phrase ellipsis to be licensed by auxiliaries like  can cf., 2004. Aleave the UK too.6. a. John will leave the UK and Bill will leave the UK either.b. John will not leave the UK, and Bill will not do, which is believed to behave similarly to the Chinese shi ‘BE’ in licensing some ΣP-ellipsis in English . According to do is positioned at the head of ModP, which is the same as the other auxiliaries in English but different from shi ‘BE’ in Chinese, which is at the head of TP. Consequently, what is elided after the dummy do is a vP rather than a ΣP, leading to the fact that English allows vP-ellipsis but not ΣP-ellipsis.It is worth mentioning that a verb-phrase ellipsis in English can also be licensed by the dummy  English . As can 喜欢 小红7. 张三 喜欢 小红， 李四 也 是 xihuan Xiaohong.Zhangsan xihuan Xiaohong, Lisi ye shi Zhangsan like Xiaohong Lisi also BE like Xiaohong.‘Zhangsan likes Xiaohong, and Lisi does (like Xiaohong) too.’will leave the UK too.8. a. *Zhangsan will leave the UK, and Lisi does will not leave the UK either.b. *Zhangsan will not leave the UK, and Lisi does -eul ‘will’ in the Korean sentence in (9), are verbal suffixes, and thus deleting a verb phrase in a sentence and leaving the auxiliary alone would produce a ‘stray affix’It has been observed in the literature that languages like Japanese and Korean do not allow auxiliaries to license a verb-phrase ellipsis. This is because auxiliaries in these languages, like 9. 존이 영국을 떠날 거야. 빌도 영국을 떠날 거야.Jon-i yeonggug-eul tteona-l geoya. Bil-do yeonggug-eul tteona-l geoya.John-NOM England-ACC leave will Bill-too England-ACC leave will.‘John will leave the UK, and Bill will (leave the UK) too.’ya야 ‘BE’ya ‘BE’ in Korean can include an auxiliary ) and a negator ). According to ya is inserted to the head of TP after a focus-movement process and the deletion of a ModP. Based on the derivation analysis and the examples above, it can be summarised that the lexical item ya occupies the head of TP, a position higher than auxiliaries in Korean. On the basis of this analysis, we can assume that in Korean, the scope of the ellipsis licensed by ya is a ΣP, which can include an auxiliary and a negator, and that Korean allows ΣP-ellipsis, but not vP-ellipsis.However, it is found that a verb-phrase ellipsis in Korean can be licensed by a lexical item 영국을 떠날 거야.10. a. 존이 영국을 떠날 거야. 빌도 yeonggug-eul tteona-l geoya.10. a. Jon-i yeonggug-eul tteona-l geoya. Bil-do John-NOM England-ACC leave-will Bill-too England-ACC leave-will.‘John will leave the UK, and Bill will (leave the UK) too.’영국을.b. 존이 영국을 떠나지 않을 거야. 빌도 yeonggug-eul.Jon-i yeonggug-eul tteona-ji an-heul geoya. Bil-do John-NOM England-ACC leave not will Bill-too England-ACC.떠나지 않을 거야.tteona-ji an-heul geoya.leave not will.‘John will not leave the UK, and Bill will not (leave the UK) either.’Cross-linguistic differences with regard to the availability of vP-ellipsis and ΣP-ellipsis are summarised in Much evidence of L1 influence on adult L2 speech production has been reported in the literature, and many features in L2 oral production find their origin in the.L1  there is no decrease in the suppliance of /is/ or /s/ when there is a complex subject; (iii) suppliance of /s/ with a complex subject is disrupted when there is an intervening prepositional phrase (PP); however, suppliance of the copula /is/ is only disrupted where the PP contains a plural N, not when both Ns are singular. The similar behaviours of the two groups in two groups. Results of an oral completion task show that both groups perform strikingly similarly; (i) the copula While evidence for the absence of L1 influence in L2 speech production is emerging, it is still not as robust as evidence for such influence. In addition, the variety of language phenomena tested for the former is still rather limited. More importantly, answers are yet to be found as to why there is absence of L1 influence on some L2 structures given that L1 transfer is a rather pervasive phenomenon in L2 speech production.There has been considerable linguistic research on the syntactic mechanism underlying ellipsis e.g., , as wellOn the basis of the cross-linguistic differences with regard to the (un)availability of vP-ellipsis and ΣP-ellipsis in English, Korean as well as Chinese, the following research questions are asked in this study.Research Question 1. Is English- and Korean-speaking L2 Chinese beginners’ oral production of vP- and ΣP-ellipses influenced by their L1s?Predictions: On the basis of the Full Transfer (FT) Hypothesis  were selected. Payments were given to every participant as a token of thanks for their participation in the study.Participants’ working memory capacity is also controlled. The task chosen in the current study to test participants’ working memory capacity is the backward digit span task, which is one of the subtests of Wechsler Adult Intelligence Scale–Fourth UK Edition , and hasF = 465.763, p < 0.001). Post hoc Scheffé tests indicate that all learner groups are significantly different from the NS group. The results also show that there is no significant difference between any of the two corresponding language groups in their scores in the cloze test; that is, no significant difference is found between the EB Group and the KB Group (p > 0.05), between the EI Group and the KI Group (p > 0.05), or between the EA Group and the KA Group (p > 0.05). These indicate that all of the English groups are compatible with their corresponding Korean groups with regard to their Chinese language proficiency.The remaining participants are divided into seven groups based on their native languages and their performance in a cloze test. The cloze test is adopted from Participants are required to complete a language background questionnaire and the working memory test prior to the main experiment, which includes an elicited imitation taskqing huida ‘please answer’. Participants are then required to make a decision about whether the sentence they have just heard matches the contextual information on the screen, by selecting an option of “Match,” “Mismatch” or “I do not know” on an answer sheet provided. This serves as a comprehension task to draw participants’ attention to the meaning rather than the form of the eliciting utterance. This also provides a way to measure participants’ comprehension of the utterance. Obviously, without correct comprehension, it would be difficult for the participant to recall the utterance. These procedures are also to ensure that there will be a time interval of at least 3 s between the presentation of the eliciting utterance and the start of the recalling. All this helps to make sure that the utterance produced by the participant is reconstructive, “requiring participants to process, rather than repeat verbatim, language stimuli”  and (12)), with each condition having six test sentences. Each test sentence consists of three clauses, and each sentence contains 22 or 23 Chinese characters. The pictures and contextual information for (11) and (12) are provided in 11. Example of the vP-ellipsis condition:hui, tamen hui yiqi qu.Mingtian Xiaoming hui qu Beijing, Xiaoli ye Tomorrow Xiaoming will go Beijing Xiaoli also will they will together go.kan Tian’an Men.see Tian’an Men.‘Xiaoming will go to Beijing tomorrow, and Xiaoli will too. They will go to see Tian’an Men together.’12. Example of the ΣP-ellipsis condition:Mingtian Xiaoming hui qu Lundun, Xiaoli ye shi. Tamen dou shi diyi-ci.tomorrow Xiaoming will go London Xiaoli also BE they both be first-CL.chuguo lvxing.go abroad travel.‘Xiaoming will go to London tomorrow, and Xiaoli will too. This is their first time to travel abroad.’Xiao Wei instead of Xiao Li) and replacement of verbs or nouns with synonyms, were not treated as incorrect responses, as this kind of mistake does not affect the use of ellipsis. We categorized the responses into four categories, as described in (13).Participants’ responses in the elicited imitation task were recorded, transcribed and analysed. In the data trimming process, unclear responses, responses not immediately produced, and responses where the second clause is not produced or largely incomplete were removed and treated as missing values. Note that the choice of incorrect names  were considered to have attended to meanings of the eliciting sentences. The results show that all groups’ accuracy rates are higher than 93%, indicating that they have good comprehensions of the eliciting sentences in the task.As can be seen in As shown in In the ΣP-ellipsis condition, the two beginner groups again behave similarly; they rarely produce target responses with ΣP-ellipsis (the EB Group: 0% and the KB Group: 1%) even though ΣP-ellipsis is allowed in Korean. In contrast, they produce responses with overt ΣP at very high rates (the EB Group: 90% and the KB Group: 96%), in spite of that fact that the eliciting utterances contain ΣP-ellipsis. Again, absence of L1 transfer is observed in beginners’ oral production of ΣP-ellipsis. With the increase of their Chinese proficiency at intermediate and advanced levels, L1 Korean groups produce an increasingly higher proportions of target responses with ΣP-ellipsis  than L1 English groups .The number of L2 learners’ target responses were submitted to a linear mixed-effect models under the lme4 package in R version 4.1.0 . The fixed predictors include Proficiency , L1  and Condition , and the interactions of Proficiency * L1, Proficiency * Condition, Condition * L1, and Condition * L1 * Proficiency. Participant and test items were entered as random factors for intercepts and slopes. A maximal model was first established, based on which the optimal model was found by backword elimination procedure. The formula of the optimal model is Score ~ Condition x L1 x Proficiency + (1 + L1 + Condition | Participant) + (1 + Proficiency + L1 | Item).p = 0.149). Similarly, p = 0.444). In contrast, p< 0.001). Consequently, there is no overall effect of either L1 or condition, but there is a crossover interaction. From p< 0.001). This indicates that the number of target responses varied across different proficiency groups. p = 0.279).The model output is presented in post hoc comparisons were conducted through the emmeans package . This suggests that L1 English beginners do not produce more vP-ellipsis sentences in their L2 Chinese speech production than L1 Korean beginners, and L1 Korean beginners do not produce more ΣP-ellipsis sentences in their L2 Chinese speech production than L1 English beginners.In order to explore difference between target responses of proficiency-matched L1 English and L1 Korean groups, thereby answering the questions about the occurrence and disappearance of L1 influence at different L2 stages, Turkey  package  in a simβ^ = 0.2692, SE = 0.0779, t = 3.458, p < 0.05; ΣP-ellipsis condition, EI vs. KI: β^ = −0.3421, SE = 0.0779, t = −4.394, p < 0.01), indicating that L1 influence is absent at the beginner levels, but occurs at the intermediate level. At the advanced level, L1 English and L1 Korean groups’ frequencies of target responses in the ΣP-ellipsis condition differ significantly from each other , indicating the persistence of L1 influence in the two advanced groups’ L2 Chinese oral production of ΣP-ellipsis. In contrast, the advanced groups’ frequencies of target responses in the vP-ellipsis condition are not significantly different , suggesting disappearance of L1 influence in the two advanced groups’ L2 Chinese oral production of vP-ellipsis.To explore the answer to the second research question about the role of L1 in L2 developmental stages, intermediate and advanced learner groups’ results were examined. In contrast, L1 difference is found to be a significant factor in L1 English and L1 Korean intermediate learners’ L2 Chinese production of vP- and ΣP-ellipsis  Hypothesis FTFA, , 1996, wRecall that in comparison with utterances with vP- or ΣP-ellipsis, “complete” sentences with no ellipsis are grammatical but stylistically heavy and unconcise in Chinese. It seems likely that no syntax-stylistics interface is established in beginner learners’ L2 Chinese, leading to a breakdown at a syntax-stylistics interface in their handling of sentences with vP- or ΣP-ellipsis. As beginner learners have limited L2 knowledge and unsophisticated coordination between information from different cognitive domains, such as syntax and stylistics, the mechanisms for their L2 oral production tend to be geared for syntactic “completeness” and are unlikely to be susceptible to any stylistic requirement, even though the syntax-stylistics interface is available in their L1s. As a result, this insensitivity to stylistic requirements at L2 initial stages leads to the absence of vP- and ΣP-ellipsis observed in L1 English and L1 Korean beginners’ L2 Chinese oral production. That is, L2 learners’ production at the beginner level is governed exclusively by basic essential syntactic computations and it is immune to stylistic requirements, which overrides L1 transfer of the syntax-stylistics interface from their L1s to their L2 speech production, leading to the absence of the influence of their L1 vP- or ΣP-ellipsis on their L2 Chinese oral production of utterances with vP- and ΣP-ellipsis in the current study.If the analysis above is on the right track, it is reasonable to assume that, with improved L2 Chinese language proficiency and their increased automaticity in L2 Chinese oral production, and with more exposure to vP- and ΣP-ellipsis in their L2 Chinese input, they are more likely to produce utterances with vP- and ΣP-ellipsis, and this tendency is indeed observed in our intermediate and advanced learners’ data. At the same time, L1 influences are detected at intermediate and advanced levels as well, where English speakers are found to produce more utterances with vP-ellipsis in their L2 Chinese oral production than Korean speakers, and in contrast, Korean speakers produce more utterances with ΣP-ellipsis than English speakers. This finding is on a par with what is reported in The absence of L1 influence at beginner levels found in the present study is also in conformity with the finding concerning beginner learners’ L2 Chinese oral production of utterances with object-ellipsis in It should be acknowledged that with the data from and the design of our experiment, we are not in a position to pinpoint whether and to what extent the breakdown at the syntax-stylistics interface or the operations of checking and deleting is the main reason behind the absences of L1 transfer in beginner learners’ L2 Chinese oral production of utterances with vP- and ΣP-ellipsis. It is likely to be a joint effect of the two. We have to leave this issue for future research.+ β”  in “Cross-linguistic differences of verb-phrase ellipsis in Chinese, Korean and English”. We believe that what is elided can be measured on the basis of computational complexity involved, which, in turn, can affect early or late disappearance of L1 influence. The asymmetry in the disappearance of L1 influence in speech production of vP- and ΣP-ellipsis at advanced levels can be accounted for with the help of the measurement of computation complexity in feature checking, as in + β” , p.8. WeAccording to this metric, the more items a verbal identity checking operation involves, the more computational complexity the operation has. L2 structures with less computational complexity are expected to be acquired more easily than those with more computational complexity. In the current case, the operations on the vP-ellipsis are computationally less complex than the ΣP-ellipsis, because the former involves identity checking and deleting of only a vP and an NP object, but the latter requires identity checking and deleting of not only a vP and an NP object, but also a model and a negator. Although Korean does not have the vP-ellipsis, L1 Korean learners are able to overcome the disadvantage of not having vP-ellipsis in their L1 and acquire the less complex vP-ellipsis construction at a relatively early stage in their L2 Chinese acquisition. In contrast, L1 English learners do not allow the ΣP-ellipsis in their L1. In addition, the ΣP-ellipsis in the target language Chinese is computationally more complex than the vP-ellipsis, requiring identity checking and deleting of more items than vP-ellipsis, and as a result, their L1 English grammar is relied upon more when Chinese sentences with ΣP-ellipsis is dealt with, delaying the disappearance of L1 influence in their L2 Chinese oral production of utterances with ΣP-ellipsis. This explains why L1 influence is shorter-lived in L2 Chinese oral production of vP-ellipsis than ΣP-ellipsis.The current study tracks the role of L1 in L2 speech production of Chinese verb phrase-ellipsis structures at different stages of L2 development. One finding of the study is the absence of L1 influence on L2 Chinese speech production until intermediate and advanced levels. Both L1 English and L1 Korean learners of L2 Chinese at beginner levels tend to produce complete responses with no ellipsis, in spite of the fact that vP-ellipsis is allowed in English and that ΣP-ellipsis in Korean. This finding provides us with evidence against the FT Hypothesis proposed by FTFA, , 1996, wThe original contributions presented in the study are included in the article/Supplementary material, further inquiries can be directed to the corresponding author.Ethical review and approval was not required for the study on human participants in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.LZ did the data collection and statistical analyses. BY made substantial contributions to the theoretical framework for the findings of the study. LZ and BY made equal contributions to the design of the experiment, data interpretation, and the writing of the manuscript. Both authors contributed to the article and approved the submitted version.The work was supported by Shanghai Planning Office of Philosophy and Social Science (Grant No. 2022EYY009).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.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Motor imagery (MI) has emerged as an individual factor that may modulate the effects of attentional focus on motor skill performance. In this study, we investigated whether global MI, as well as its components  moderate the effect of attentional focus on performance in a group of ninety-two young adult novice air-pistol shooters . After completing the movement imagery questionnaire-3 (MIQ-3), participants were asked to complete a pistol shooting experiment in three different attentional focus conditions: (1) No focus instruction condition  (2) an internal focus instruction condition, and (3) an external focus condition. Shot accuracy, performance time, and aiming trace speed  were measured as the performance variables. Results revealed that shot accuracy was significantly poorer during internal relative to control focus condition. In addition, performance time was significantly higher during external relative to both control and internal condition. However, neither global MI, nor its subscales, moderated the effects of attentional focus on performance. This study supports the importance of attentional focus for perceptual and motor performance, yet global MI and its modalities/perspectives did not moderate pistol shooting performance. This study suggests that perception and action are cognitively controlled by attentional mechanisms, but not motor imagery. Future research with complementary assessment modalities is warranted to extend the present findings.The online version contains supplementary material available at 10.1186/s40359-023-01047-z. Individuals perform motor tasks with differing levels of attention. Traditional views considered attention as a passive spotlight or gatekeeper, acting prior to perceptual processing to merely filter out undesirable inputs in favor of others  –6. In co“representations … of sensory information without a direct external stimulus” [perceptual processing, in the absence of immediate sensory input from a relevant sense-modality [Aside from attentional focus, mental imagery is another cognitive mechanism that may affect individuals’ perceptual-motor performance. Given the mental imagery definition as timulus”  or percemodality , 25, sommodality . Studiesmodality . In othemodality , 27. Premodality . That ismodality  as both modality  and percmodality , 31 and modality , 33. Furmodality  and convmodality . Based omotor imagery  [perspectives  have potential unique contributions to outcomes. To the best of our knowledge, only one recent study in children distinguished between MI perspectives , showing that while high levels of kinesthetic MI deteriorated overhand ball throwing learning in children adopting an external focus, external visual MI dominance resulted in superior motor learning for children adopting an external focus [or attentional focus, and also given the existence of some inconsistencies regarding the role of kinesthetic MI on attentional focus effects, we employed additional tasks and outcome variables to complement traditional performance indicators related to end-point accuracy. To this end, we measured performance time, aiming point stability , and performance accuracy during shooting performance of a group of young novice 10-m air-pistol shooters.A number of previous works have attempted to provide evidence regarding the modulating roles of ecution)  on motorecution) , and MI ecution)  during decution) –41. Furtecution) , 42, 43.ecution) . In addiecution) , 42, 43 ecution) . TherefoNinety-two young adult university students  with normal or corrected to normal vision, and with no self-reported musculoskeletal or postural disorders voluntarily participated in the study. Of note, a few incomplete datasets were excluded from the final analyses due to general optical system failure.The MIQ-3 is a 12-item questionnaire  to measuThe participants were asked to shoot an air-pistol as accurately and as quickly as possible at an electronic target 10 m away in an indoor environment. The SCATT shooting system  was used to quantify pistol shooting performance, congruent with prior work . The SCAFollowing completion of the MIQ-3, participants began the shooting task. After a short familiarization period, participants were asked to shoot at the target in three different attentional focus conditions: (1) control condition, (2) IF, and (3) EF. Participants completed their shooting performance under control (no focus instruction) conditions first, then ordering of internal and EF conditions was counterbalanced between participants. Similar to previous attentional focus studies, we issued participants the control focus condition first, followed by the counterbalancing of attentional focus conditions, to ensure one condition could be used as a stable control that was not biased by previous attentional focus instruction  , 50. WhiFirst, repeated measure analyses of variance were performed to investigate if shot accuracy was different among the attentional focus conditions. Similar analyses were done for performance time and aiming trace speed between attentional focus conditions. An alpha level of p < .05 was set a priori, and post-hoc analyses were performed using Bonferroni adjustments as appropriate. In addition, we ran simple regression analyses to investigate potential associations between each MI measure and each air-pistol shooting performance measure in different attentional focus conditions . Also, the association between performance time and shot accuracy, and between aiming trace speed and shot accuracy during each attentional focus condition were examined to help interpret findings. Finally, using MEMORE process macro , we ran Descriptive statistics of participants’ internal visual MI, external visual MI, and kinesthetic MI scores are shown in Table F  = 4.45, p = .015, η = 0.046). Pairwise comparisons using Bonferroni adjustments revealed that while accuracy during external focus  was not significantly different than other attentional focus conditions, participants were more accurate during control  relative to internal focus  condition (p = .017). Performance time was different between conditions  = 21.47, p = .019, η = 0.21). Pairwise comparisons revealed that participants had higher performance time during external  relative to both control  and internal focus , and performance time during internal focus was also significantly higher than during the control focus condition (p = .03). Finally, the effect of attentional focus conditions on aiming trace speed was significant  = 3.38, p = .046, η = 0.041), although pairwise comparisons failed to identify the location of effect. Mean and standard error of shot accuracy, performance time, and aiming trace speed during different attentional focus conditions have been shown in Figs. Results indicated a significant difference in participants’ performance accuracy between attentional focus conditions . There were no associations between MI total score or its subscales with performance time during any focus conditions . There were no associations between MI total score or its MI subscales with aiming trace speed during any focus conditions .There were no associations between MI total score or its subscales with shot accuracy during any focus conditions  nor any of the three subscales  moderated differences in shot accuracy between attentional focus condition.Neither total MI score (p range = 0.33 − 0.91) nor any of the three subscales  moderated differences between foci of attention and performance time.Neither total MI score (p range = 0.69 − 0.70) nor any of the three subscales  moderated differences between foci of attention and aiming trace speed.Neither total MI score  during different attentional focus conditions. Based on several lines of research, we expected that individual differences in MI would play a crucial modulating role in cognitive control of both perceptual and motor performance. Our findings however failed to show any modulating role for MI. We nevertheless observed that attentional focus affected perceptual and motor outcomes measured in this study. More particularly, an internal focus resulted in less accurate shots than control focus. In addition, movement time was shorter during control relative to both internal and external focus, whereas an external focus resulted in longer movement times than other attentional foci.too difficult for our inexperienced individuals as they had to shoot towards a standard, yet relatively small bulls-eye (11.5 mm diameter) from a distance of 10 m. Prior literature proposed a hypothesis that suggests overly difficult tasks  do not allow for beneficial adoption of superior cognitive strategies such as an external attentional focus [Several attentional focus hypotheses, including the constrained-action hypothesis and self-invoking trigger hypothesis, have previously suggested that an internal focus hinders perceptual and motor functions due to controlled processing that interferes with automatic performance , 53, 54.al focus , possiblal focus . Althougal focus –60. Our Given an external focus did not facilitate our participants’ accuracy while increasing their performance time, alternative explanations are warranted given the extant literature on this topic . For instance, during control processes of goal-directed aiming tasks, successful visual processing is necessary to achieve desired movement accuracy . Future First, despite including a relatively large number of participants in the study, our participants were not particularly poor at motor imagery, as our participants had self-reported MI scores that were relatively higher than a score that can be deemed as poor imagery ability. In the MIQ-3, a score of 4 is neutral (neither easy nor hard), and individuals that score 3 or lower are those who report difficulty in MI ability. As our descriptive results show, our participants had mean MI scores  that are considered relatively high (range from 5.81 to 5.87). However, rather than considering this as a methodological limitation of the present work, we consider this a unique finding as individuals in our study had less difficulty imagining their action from different modalities and perspectives, compared with previous works reporting relatively high MI abilities [Second, although, like many previously published pistol-shooting-related work [Third, We should also note that our participants were novices, and therefore their little experience of physically executing the imagined action may have resulted in inefficient (unorganized) neurocognitive processing [Fourth, the MIQ-3 used in our current study does not measure some important aspects of mental imagery such as mental imagery vividness- a diagnosis tool for identifying individuals with extreme imagery conditions [Fifth, and finally, while MI may be action specific [Our study failed to provide support for the suggestion that perception is cognitively controlled by means of mental imagery . Therefobilities , 63–65. bilities  conductebilities  exhibit bilities  considerbilities . Therefoted work , 67, 68,ocessing , that asnditions –72 whichnditions –77. Furtspecific , the MIQOur study has some limitations that should be acknowledged. We used a laboratory-based task that may reduce the complexity of what occurs during real situations ; therefoIn conclusion, this study showed that participants’ self-reported baseline MI and its subscales do not moderate attentional focus effects on novices’ air-pistol shooting performance accuracy, performance time, and aiming trace speeds. These findings may suggest that individuals’ MI does not affect cognitive control of perceptual and motor functions. However, an internal focus may reduce shot accuracy relative to control focus. Importantly, an external focus may result in an increased performance time to ensure the task goal. The study highlights the importance of future studies to enhance our theoretical and practical knowledge regarding mental imagery, and attentional focus in sport science and rehabilitation.Additiona file 1.Supplementary materials. Secondary data analysis using motor imagery dominance.


The band structure of the monolayer and the armchair ribbons of different widths are discussed with illustrations. The time-dependent wavefunctions of the systems and the expectation values of interest are determined by solving the coupled equations of the band amplitudes “exactly” . First, simulations are made for the population excitation in the conduction band (CB) from the valence band (BV), the VB-CB interband correlation (or “coherence”), the intraband, the interband and the total currents in the monolayer graphene. The graphene currents are compared with the corresponding currents induced in an armchair ribbon . The change from the 2D monolayer to the 1D ribbon shows a remarkable transition of the dominance of the intraband current that leads to a near steady total current in the monolayer, to a dominance of the interband current in the ribbon that induces an oscillatory current in the ribbon beyond the pulse duration. The difference observed might be a combined effect of the “confinement” in one dimention and a finite band-gap minimum in the case of the ribbon. However, this transition should be further investigated for better clarity. A brief comparison of the radiation spectra emitted from the monolayer and from the ribbon is also made. They show a grossly similar structure and a relative insensitivity with respect to the detailed structure of the targets chosen. This might be due to the dominance of virtual continuum-continuum transitions, to and from the bands states, that lie behind the fundamental quantum process of high harmonic emissions. Lastly, the dependence of the charge currents, induced in a ribbon of unit width (N = 1), on the carrier-envelope-phase (CEP) of the incident laser pulse is investigated. It is seen that the shape of the main part of the current produced in the ribbon can be fully reversed by changing the CEP of the ultrashort laser pulse from 0 to π. More generally, it is suggested that the pulse shape of the charge carriers in the ribbon could be designed by similarly tailoring the form of the vector potential of the incident laser pulse.In this work we investigate quantum mechanically the interaction of an intense ultrashort laser pulse with the graphene monolayer as well as with the armchair graphene ribbons of different widths. We consider a tight binding (TB) Hamiltonian of the monolayer graphene and give two rules for deriving the dispersion relations of the armchair graphene  Their method makes use of the side walls of 6H-SiC mesa structures to epitaxially grow the armchair ribbons of different widths on them, while the ARPES technique was used to investigate the electronic structure of the sub-bands of armchair ribbons that revealed the presence of band gaps in most ribbons as well as a gapless pair of bands for ribbons of certain widths . This development opens up new prospects of further research on the effect of quantum confinement and of potential applications of the ribbons in semiconductor electronics, specially, where the monolayer graphene is not directly usable due to its missing band gap.Graphene is a two dimensional hexagonal one-atom-thin monolayer of carbon atoms that shows remarkable material, electrical and optical properties e.g.  with mucand with armchair graphene ribbons. To this end first we consider an analytical TB (tight binding) Hamiltonian in the reciprocal lattice space, determine its eigenvalues and eigenfunctions, give two simple rules for constructing the band-system of armchair ribbons (of any width) from the graphene bands and, briefly illustrate the lattice structure of the monolayer graphene and of the armchair ribbons. Next, the current and the transition dipole operators (relevant for the study of laser interactions) are constructed analytically from the TB Hamiltonian. The laser interaction is introduced using the minimal coupling prescription in the reciprocal lattice space and the time-dependent Schrödinger equation of the interacting system is obtained in the adiabatic representation  the interactions of an intense ultrashort laser pulse with the monolayer graphene tion cf. . To solvtion cf.  for the a = |a1| = |a2| is the lattice constant. The nearest neighbour (nn) distances from one atom (red) of the cell are d1| = |d2| = |d2| = aCC, the carbon-carbon bond length, and, K± = ±{4π/(3a), 0} are the two non-equivalent “Dirac points” of band degeneracy . Note that the lattice constant M, as well as the Dirac points . The “armchair” structure of the horizontal edge and the zik-zak structure of the vertical edge of the monolayer graphene sheet are to be noted here.The lattice structure of a two dimensional graphene monolayer is illustrated schematically in 2, as used in this work, we tested (following the suggestion of an anonymous referee) and found no significant effect of the band asymmetry with non-zero overlap integral s0 = 0.129, as in this work, and s0 = 0 for the symmetric bands. This is apparently due to the high values of the dipole operator in the vicinity of the Dirac points  interactions, the stationary wavefunction ψ(k) of the graphene monolayer can be written as a linear combination of the two Bloch functions associated with the two pz orbitals (per cell). We may then apply the variational principle as usual to construct the expectation value of the energy operator H0, and arrive at the following 2 × 2 variational matrix equation (e.g. ψ(k) = {ψ1(k), ψ2(k)} as well as the energy of the least bound pz orbital, ϵp2:H0(k) is a 2 × 2 matrix with elementsAssuming two carbon atoms per unit cell (red and black dots in the rhombus of ion e.g.  with resh(k) can be expressed by its real amplitude f and phase χ as:g0 is the “hopping” integral (the nearest neighbour interaction matrix element); the lattice constant aCC is the carbon-carbon bond length. The 2 × 2 overlap matrix S is defined by its elementss0 is the dimensionless overlap integral. In this work we have followed the convention ; we also adopt the parameter values g0 = 3.033 eV, s0 = 0.129, and the C-C bond length aCC = 0.142 nm, quoted therein  is the 2D lattice-momentum in the -plane of the monolayer graphene. The corresponding normalised eigenvectors are,The eigenvalues and the eigenvectors of s0 = 0.129 is small compared to 1, it appears in the first order in the denominators in the eigenvalues  then, one obtains a pair of symmetric energy bands. This is particularly so near the Dirac points where the interaction with the laser field is dominant. One may note that with s0 = 0.129 the energy bands are generally asymmetric and the VB and CB have different band widths .We note that although for graphene the square of envalues  and so ienvalues ). Note acf. e.g. . The Hamminimal coupling prescription  is the vector potential associated with the laser electric pulse F(t), and is given by the definition Introduction of the laser-graphene interaction in the system is readily implemented within the present theory by the iltonian  by the sk(t) in terms of the adiabatic  basis states ψ1 (kt) and ψ2 (kt) of H (kt) and write:To solve it, we may first expand the total wavefunction Ψψ1 (kt) and |2⟩ ≡ ψ2 (kt) from the left to get the pair of coupled equations for the time-dependent occupation amplitudes of the valence and the conduction bands, c1  and c2 , respectively:We substitute it in V11 and V22 above, can be transformed away by a unitary transformation of the amplitudes without affecting the probabilities and the expectation values calculated with respect to the total wavefunction of the system .Note that a common term, x and y components of the velocity operator are obtained in the present theory analytically from the Hamiltonian 6) by differentiation with respect to the components of the lattice-momentum k = ,The Jop = euop and the transition dipole operator can be obtained from the velocity operator using the Heisenberg equation of motion:The quantum mechanical current operator defined as ψ1 > and |ψ2 >, with the respective eigenvalues, E1 and E2, of H  may be defined generally in the form x and y axes, respectively; the associated vector potential is given by For the applications, the incident laser field V12 (kt) and V21 (kt) in χ(kt) that appears in We point out in passing that the coupled dynamical expectation value of the “current” along the x and y axes, using the interacting total wavefunction of the system, Ψ, and summing over the k-states of the first Brillouin zone (BZ) including the 2-fold spin- and valley-degeneracy of graphene, respectively gs = 2, and gv = 2:k-space and LD, for the “volume” in the lattice-space (with D = 2 for the monolayer graphene and D = 1 for the armchair graphene ribbons).Finally, we give the expressions for the quantum mechanical intraband current, while the third sum that depends on the VB-CB correlation (or “coherence”) term is referred to as the interband current. It is convenient for most purposes to deal with the corresponding normalised currents  and the conduction band (CB = |2⟩), is often referred to as the We note that the normalised currents are in a. u., with To complete the definitions we also give the matrix elements appearing above, explicitly:c1  and c2 . They are used to determine the total wavefunction of the interacting system and to construct the expectation values to investigate first the excitation of the CB population and the interband correlation (or “coherence”). Next, the intraband and the interband currents as well as the total current are simulated for the case of graphene monolayer and an armchair ribbon . Also simulated are the spectra of the radiation emitted from the monolayer and the ribbon currents. Lastly, the effect of the so-called carrier-envelope-phase  on the shape or symmetry of the current produced in a ribbon  is studied. It is suggested that ultrashort charge-current pulses of desired shape or symmetry might be possible to design by tailoring the vector potential of the laser pulse similarly. The results of the simulations carried out are illustrated graphically, and are compared, and discussed in the next section.For the simulations made in this work, we have solved the coupled e = m = ℏ = 1, c = α−1 = 137.036. We note also that [1 a. u.] of length = a0 = 1Bohr = 0.0519 nm [1 a. u.] of time = t0 = a0/(αc) = 24.19 as, and [1. a. u.] of e = 1.602 × 10–19 C.Unless stated explicitly otherwise, for the convenience of writing and the numerical simulations, in the rest of the work we have used the Hartree atomic units: kx-axis (for ky = 0). The energy degeneracy of the two bands are seen to occurr at the Dirac points  in the -plane where one can also readily recognise the hexagonal structure of the Brillouin zone of the monolayer graphene. In this work, as indicated earlier, we also consider the armchair graphene ribbons cut along the armchair edge (y-axis) with a finite number of cell widths, N, along the transverse direction (x-axis)  while the ribbon’s length is assumed to extend freely along the armchair axis (y-axis).In xis) cf. . The conWe give below two simple, yet general, rules for obtaining the entire system of energy band dispersion relations of the sub-bands of the armchair graphene ribbons (of any width N):Rule 1: An armchair ribbon of width N has N VB-CB band-pairs, r = 1, 2, … , up to N.Rule 2: The N pairs of dispersion relations of the bands can be obtained from the eigenvalues of the monolayer graphene by the simple substitution: kx → kx  = (2/a) (rπ/(N + 1)), where a is the graphene lattice constant).K). Thus, for the Dirac fermion model of armchair ribbons we get the following simple dispersion relations of the rth pair of bands of a ribbon of width N:vF ≈ c/300. It is also worth observing  in a robust and compact form of an armchair ribbon. This might be of interest for potential applications in digital/optical systems. In qy = 0, as they should (but differ elsewhere). The system of VB-CB band pairs are colour coded as follows:  → blue;  →  and,  → . For example, for N = 3, there are three VB-CB pairs of bands none of which is degenerate. However, one pair (red) shows a band-gap minimum, as in a 1D semiconductor. The “m-rules” 1) and 2) given above can be easily verified  for the three ribbons of widths N = 1, 2, and 3, shown in the figure. , does not maintain the parallel separation away from the band centre, qy = 0, unlike the “flat” bands of the full TB model, that do.) We may add that the band structure of the armchair ribbons of width N may be also viewed as possessing N “conduction channels”. They apply to the full TB dispersion relations as well as to the Dirac fermion model (applicable near the Dirac points ving cf.  that 1) Jop = euop . It is clear from the figure that the strength of the transition moment is particularly strong near the corners of the hexagonal BZ (or the Dirac points) in both positive (upper part in the figure) and negative (lower part of the figure) signs of the strength.As we have seen above, the availability of the TB Hamiltonian in the analytic form  below,  and the 2 , polarised linearly and parallel to the “armchair edge” of graphene (the y-axis):F0 is the peak electric field strength, tp is the pulse duration, ω is the circular frequency and ϕ0 is the carrier-envelope-phase (or CEP). The corresponding vector potential is given by,For the simulations in this work we have generally restricted ourselves to an intensity of 1 TW/cm2, tp = 1.5 cycles or, 4 fs).The pulse is illustrated graphically in after the pulse has ended. Simulations are made for the following quantities: 1) CB population, 2) “VB-CB correlation”, and 3) “band currents”, and the results are presented graphically below. They are normalised, as discussed above per unit “volume” . As indicated above, the units of the quantities represented are in Hartree atomic units (a.u.) . The normalised population transfer to the CB and the VB-CB correlation are computed assuming an initially fully occupied VB and an empty CB. Similar initial conditions are assumed for the simulations of the normalised band currents. They are computed from the following normalised formulas .Note that the duration of the simulation times are extended mostly up to twice the pulse duration (up to three cycles) with no field present in the last 1.5 cycles. This allows one to observe the residual response of the system 1) Normalised CB population:2) Normalised VB-CB correlation:The units for 1) and 2): a.u.] = 3) The normalised Currents: They are simulated from the y-component of the formulas, interband correlation—or the VB-CB “coherence”—(middle panel), as well as the interband current (bottom panel). The simulation duration is extended to twice the pulse duration (1.5 cycles) to 3.0 cycles. This allows one to observe the behaviour of the response after the pulse is over. The CB population is seen to increase considerably with the passage of the pulse and attains essentially a steady state superimposed by a mild modulation that persists after the end of the pulse. This is to be contrasted with the oscillatory behaviour of the interband correlation (or the VB-CB “coherence”) that shows a sub-cycle oscillation at the end of the pulse and beyond. We point out that sub-cycle oscillations and ballistic currents have been studied and observed experimentally earlier by Hommelhoff and collaborators  and the interband current (middle panel). Conceptually, the intraband current is associated directly with the sum of the electron-current in the CB and the “hole”-current in the VB. The interband current (middle panel) is associated with the interband correlation or the VB-CB “coherence” (discussed above with respect to intraband current (top panel) and reaches essentially a steady state with a mild modulation. Note that the mild modulation of the interband current causes the mild modulation of the total current beyond the duration of the 1.5 cycle laser pulse.In borators . Note th2, and a pulse duration of 1.5 cycles. In comparison with the monolayer case  in the monolayer current to the strong oscillation of the current in the ribbon does not hold universally for the ribbons  We show in 2, 800 nm, 1.5 cycle laser pulse (as in y-axis). It can be seen that both the spectra have similar qualitative characteristics—namely, a high signal for the low photon orders with a rapid fall in intensity followed by a low and broad plateau that extends to large orders (over a hundred) of the incident photon energy. They show a relative insensitivity to the detailed structure of the target chosen. This is reminiscent of the relative insensitivity also of the gross structure of the so-called “HHG” spectra of atoms/molecules. From the quantum point of view, this insensitivity of the gross structure of the spectra seen here might be due to the dominance of the virtual continuum-continuum transitions between the two band-continua, like that in the ionisation continuum of atoms/molecules that lie behind the fundamental HHG emission process [cf. e.g., review (Section 4.7), The normalised emission spectra computed here are defined by the frequency transform of the normalised currents as follows:se as in . The lasribbon by tailoring the laser pulse. It has been found recently by Hommelhoff and collaborators that the electron dynamics in monolayer graphene can be controlled by choosing the field strength and the phase of the laser field. Thus, they have observed sub-cycle Stuekelberg oscillations and field dependent change of directions of the ballistic current in monolayer graphene (armchair ribbon. The results of simulations of the currents (LHS column) are shown in π, -π/2, and π/2. Comparing the top two rows of the figure, with CEP = 0 and CEP = π, it can be seen that the symmetry of the ultrashort current pulse is fully reversed on changing the CEP of the incident laser pulse from 0 to π. More generally, the results show that the main part of the currents for different CEPs in the ribbon follow the shape of the vector potential of the incident laser pulse. This suggests the possibility of shaping an ultrashort pulse of charge-carriers in the ribbon to a desired form by tailoring the vector potential of the incident laser pulse to mimic the form.Finally, we consider the possibility of shaping the ultrashort current of charge carriers in an armchair graphene graphene . Here weand with armchair graphene ribbons of different widths is made. A TB model is used for the graphene bands and two simple rules for generating the system of sub-bands of the armchair graphene ribbons of any width, N, are given and the band structures are discussed with illustrations.A quantum mechanical investigation of the interaction of an ultra-short intense laser pulse with a two dimensional monolayer graphene interband “correlation” (or “coherence”) and the currents generated in the monolayer graphene and in an armchair graphene ribbon . It is found that the population transfer from an initially fully occupied valence band (VB) to an empty conduction band (CB), is seen to increase during the pulse and ends with a finite steady population, that persists after the pulse is over. In contrast the excitation of the interband correlation or, the VB-CB “coherence”, shows an oscillatory behaviour both during and after the passage of the pulse.Simulations are carried out to investigate, first, the laser pulse excitation of the CB population, the VB-CB intraband component, that leads to a near steady rest-current with a mild modulation. The transition to the ribbon exhibits a remarkable change from the dominance of the intraband current in the monolayer to the dominance of the oscillatory interband current in the ribbon. The ribbon appears to reduce the possible effect of band dispersion in 1D, compared to the open 2D monolayer. The difference seen could be a combined result of the quantum “confinement” effect to 1D as well as due to the difference in the band structure of the ribbon having a band-gap minimum. However, the transition to the oscillatory ribbon current does not hold universally for the ribbons of different widths and, thus, remains open to further investigations in the future for greater clarity.A comparison of the currents generated in the monolayer graphene with the current in an armchair ribbon (of width N = 3) shows that the former is dominated by the broad plateau that extends over many (over a hundred) orders of the incident photon energy. The form of the spectra are also rather insensitive to the target chosen. This is reminiscent of the gross structure and the relative insensitivity to the target chosen also for the well-known “HHG” spectra of atoms or molecules. From the quantum point of view, this insensitivity might be due to the dominance of the virtual continuum-continuum transitions between the two bands, not unlike the transitions in the ionisation continuum of atoms and molecules, that govern the fundamental HHG emission process.A brief comparison of the radiation emitted by the currents in the monolayer graphene and the ribbon (N = 3) is also made. They show a gross similarity and a relative insensitivity to the detailed structure of the targets used. The emission spectra are found to be virtually continuous in frequency and fall off rapidly in intensity with the initial photon orders and reach a low but π. More generally, the result of the simulations made shows that the main part of the pulse of the charge-carriers in the ribbon follows the shape of the vector potential of the incident laser pulse. This suggests the possibility of shaping the ultrashort pulse of charge carriers in the ribbon to a desired form by tailoring the vector potential of the laser pulse to mimic the form.Finally, the possibility of controlling the shape of the ultrashort current of the charge carriers in an armchair ribbon of unit width (N = 1) by the incident laser field is briefly studied. Simulations with different carrier-envelope-phase (CEP) of the incident laser pulse show, for example, that the symmetry of the current in the ribbon can be fully reversed by changing the CEP of the laser pulse from 0 to


We describe an autosomal dominant, multi‐generational, amyotrophic lateral sclerosis (ALS) pedigree in which disease co‐segregates with a heterozygous p.Y374X nonsense mutation within TDP‐43. Mislocalization of TDP‐43 and formation of insoluble TDP‐43‐positive neuronal cytoplasmic inclusions is the hallmark pathology in >95% of ALS patients. Neuropathological examination of the single case for which CNS tissue was available indicated typical TDP‐43 pathology within lower motor neurons, but classical TDP‐43‐positive inclusions were absent from motor cortex. The mutated allele is transcribed and translated in patient fibroblasts and motor cortex tissue, but overall TDP‐43 protein expression is reduced compared to wild‐type controls. Despite absence of TDP‐43‐positive inclusions we confirmed deficient TDP‐43 splicing function within motor cortex tissue. Furthermore, urea fractionation and mass spectrometry of motor cortex tissue carrying the mutation revealed atypical TDP‐43 protein species but not typical C‐terminal fragments. We conclude that the p.Y374X mutation underpins a monogenic, fully penetrant form of ALS. Reduced expression of TDP‐43 combined with atypical TDP‐43 protein species and absent C‐terminal fragments extends the molecular phenotypes associated with TDP‐43 mutations and with ALS more broadly. Future work will need to include the findings from this pedigree in dissecting the mechanisms of TDP‐43‐mediated toxicity. In this study Cooper‐Knock et al identified an autosomal dominant ALS pedigree associated with p.Y374X‐TARDBP. In patient tissue the authors confirmed reduced TDP‐43 protein expression, abnormal TDP‐43 fragmentation and deficient TDP‐43‐mediated splicing. This work extends the phenotypes associated with TDP‐43 mutations. The C:N‐terminal peptide ratio was calculated by dividing non‐log absolute abundances of the light peptides. Truncation peptides include one cleavage site independent of the enzyme used for digestion (giving a nonspecific digestion pattern), which suggests that cleavage has occurred endogenously prior to digestion.TDP‐43 protein fragmentation in the urea insoluble protein fraction from motor cortex tissue was quantified by immunoblot and mass spectrometry (MS) as previously described . In brie2.8g for 10 min. RNA was extracted from 250 μl lysate, with the remainder used for immunoblotting.Motor cortex tissue (~0.1 g) was lysed in 400 μl RNase free RIPA lysis buffer  using a Precellys evolution homogeniser and 8 × 1.4 mm Zirconium Oxide beads at 5500 rpm for 2 × 30 s, 10‐min incubation on ice and another round of homogenisation. Lysates were collected after centrifugation at 17,000 Protein extract concentrations were determined using a Bradford Reagent (Bio‐Rad), resolved by SDS‐PAGE electroblotted onto nitrocellulose membrane and probed using the relevant primary antibody. STMN2 (1:1000 dilution)  and TDP‐43 (C terminus) (1:1000 dilution)  were detected with horseradish peroxidase (HRP)‐conjugated rabbit secondary antibody (Promega), while α‐tubulin, clone DM1A (1:2000)  and TDP‐43 (1:3000)  were detected with HRP‐conjugated mouse secondary antibody (Promega). Immunoblots were visualised using a Licor Odyssey Fc and densitometry analysis performed using Image Studio Lite (Version 5.2.5).2.9g, 10 min, 4°C. The upper phase was collected and the RNA was precipitated overnight at −20°C with equal volume isopropanol and 1 μl glycogen  and subsequently pelleted at 17,000g, 20 min, 4°C. RNA pellets were washed with 70% DEPC ethanol and resuspended in DEPC water. All RNA samples were treated with DNaseI (Roche) and quantified using a Nanodrop (NanoDropTechnologies). Following quantification, 2 μg RNA was converted to cDNA using BioScript Reverse Transcriptase (Bioline). Human snRNA U1 ; human STMN2 , and human UNC13A  primers were used in this study. qRT‐PCR reactions were performed in duplicate using the Brilliant III Ultra‐Fast SYBR Green QPCR Master Mix (Agilent Technologies) on a C1000 TouchTM thermos Cycler using the CFX96TM Real‐Time System (Bio‐Rad) using an initial denaturation step, 45 cycles of amplification  prior to recording melting curves. qRT‐PCR data were analysed using CFX Manager software (Version 3.1) (Bio‐Rad) and quantification performed using the comparative CT method (35) and GraphPad Prism (Version 9).RNA was extracted from motor cortex using PureZOL (Bio‐Rad). Briefly, one fifth the volume of chloroform was added and tubes were vigorously shaken for 15 s followed by 10 min incubation at RT and centrifugation at 12,00033.1A Y374X truncating mutation in TDP‐43 c.1119_1120delTT) was identified in the present study. This mutation was detected in three affected kindred members Figure . In addidelTT was3.2The index pedigree is shown in Figure 3.3C9ORF72 [Neuropathological features were most prominent in lower motor neurons. There was loss of lower motor neurons that was most marked in the anterior horns of the spinal cord Figure  with BunC9ORF72 .3.4). To confirm expression of the mutated allele we analysed protein lysates from cultured fibroblasts, isolated from three members of the kindred, and motor cortex tissue, isolated from one member. The truncated protein was expressed  . Y374X‐TMotor cortex tissue from a single Y374X‐TDP‐43 ALS patient was fractionated to enrich for pathological insoluble species Figure  althoughMS‐PRM enabled antibody‐free quantification of TDP‐43 fragments and confirmed the findings of the immunoblot analysis. Heavy isotope‐labelled peptides corresponding to the N‐ and C‐terminal ends of the TDP‐43 protein Figure  were syn3.6POLDIP3/SKAR gene is altered by loss of TDP‐43 function resulting in exclusion of exon 3, and so RT‐PCR for this gene was performed [t‐test p = 0.2165, Figure Our analysis suggests that the quantity of total TDP‐43 protein is reduced in the presence of the Y374X mutation Figure  and thererformed , 27. The) and protein .We also utilised an indirect measure of TDP‐43 splicing function which has been linked directly to ALS pathogenesis. Recently, reports have connected reduced nuclear TDP‐43 content to missplicing of STMN2 and UNC13A and neurotoxicity in ALS , 10. Mis4Here, we have presented data from a multi‐generational ALS kindred with a Y374X truncating mutation within TDP‐43. This is the first time this atypical mutation has been shown to co‐segregate with ALS in a single pedigree, which represents good evidence for monogenic pathogenicity. The age of onset varied significantly in our pedigree which may explain the observation of this mutation previously in an apparently sporadic ALS case .Whilst dysfunction of TDP‐43 is undoubtedly associated with ALS  and gainThe discovery of TDP‐43 CTF  and coulIt should be noted that we tested TDP‐43 fragmentation in motor cortex tissue for consistency with our previous work . HoweverC9ORF72‐FTLD neurodegeneration can be associated with RNA foci and dipeptide‐repeat protein inclusions without TDP‐43 pathology [A caveat in our study of TDP‐43 fragmentation function is that the analysis is based on a single Y374X TDP‐43 ALS patient compared to up to five neurologically normal controls. In addition we focused on the motor cortex which was devoid of classical TDP‐43 pathology in this case. However, we note that there is precedence in the literature for disease‐associated neuronal dysfunction in the absence of classical TDP‐43 pathology. For example, TDP‐43 pathology is relatively more frequent in the spinal cord compared to the motor cortex even when there is clearly clinical evidence of upper motor neuron involvement . In C9ORathology . Finallyathology .Of significant interest is that the major domain identified to be abnormally phosphorylated in ALS cases, S409/410, is absent from the Y374X truncated protein , 35. HowIn conclusion we have demonstrated that the Y374X TDP‐43 truncating mutation is very likely to be a cause of autosomal dominant ALS. Moreover this mutation is associated with typical TDP‐43 pathology at a macromolecular scale in the spinal cord but also with atypical insoluble TDP‐43 protein fragments and reduced TDP‐43 protein function. These data extend the spectrum of observations associated with TDP‐43 pathology in ALS and will inform future work aimed at ameliorating neurotoxicity associated with this protein.J.C.K. C.H., P.J.S, R.J.M, J.R.H, and J.K. conceived and designed the study. J.C.K., E.F., J.R.H, M.S., S.P.A., T.M., T.S., L.C., G.M.H., C.H., J.K., and S.B.W, were responsible for data acquisition and data analysis. J.C.K., E.F., M.R.T., K.T., O.A., J.R.H, T.H.J., M.S., T.M., S.P.A., T.S., L.C., G.M.H., C.H., J.K. S.B.W, and P.J.S. were responsible for the interpretation of the findings. T.H.J., J.C.K., E.F., M.S., C.H., J.R.H., R.J.M., and P.J.S. drafted the manuscript with assistance from all authors. All authors meet the four ICMJE authorship criteria, and were responsible for revising the manuscript, approving the final version for publication, and for accuracy and integrity of the work.Emily Feneberg, Kevin Talbot, Martin R. Turner, and Olaf Ansorge have a patent filed for the TDP‐43 sequences described in this work (Patent application no. 2004863.3). Other authors delare no conflict of interest.Table S1 Sequenced genes with no identified ALS‐associated mutation in members of the Y374X‐TDP‐43 ALS pedigree.Click here for additional data file.


We integrate these graphene-coated glass rovings into a vacuum-infused epoxy–glass fabric composite and also demonstrate the potential use of as prepared graphene-based composites for de-icing applications.Graphene-based de-icing composites are of great interest due to incredible thermal, electrical and mechanical properties of graphene. Moreover, current technologies possess a number of challenges such as expensive, high power consumption, limited life time and adding extra weight to the composites. Here, we report a scalable process of making highly conductive graphene-based glass fibre rovings for de-icing applications. We also use a scalable process of making graphene-based conductive ink by microfluidic exfoliation technique. The glass fibre roving is then coated with graphene-based conductive inks using a dip-dry-cure technique which could potentially be scaled up into an industrial manufacturing unit. The graphene-coated glass roving demonstrates lower electrical resistances (∼1.7 Ω cm We report a scalable process of making highly conductive graphene-based glass fibre rovings and their integration into a vacuum infused epoxy–glass fabric composite. We then demonstrate the potential use of as prepared composites for de-icing applications. Whereas ice accumulation on a wind turbine can cause mechanical and electrical failures; results in up to 50% power losses.10 Several thermal, chemical and mechanical methods8–11 have been developed for eliminating the surface ice such as chemical fluid systems,9,11 pneumatic boots,12 electro-impulsive,13 hot air system,11 ultrasound system,7,14 microwave technology15 and electro-thermal de-icing system.2 Among these, electro-thermal de-icing technique is considered to be the most effective and energy efficient due to its ability to control the temperature and heat dissipation by Joule heating.16Recent years have seen significant interest in developing smart de-icing systems due to problems associated with the ice formation in many industrial applications such as aircrafts,17 However, ice accumulation reduces the advantages that the composite brings to the structure. The electro-thermal system is identified as one of the most promising de-icing systems for polymer composites, as it does not cause delamination and damage to composite structure.9,11 However, the application of the electro-thermal system within composites is limited by the poor thermal conductivity and high thermal sensitivity of polymeric materials.18,19 Many studies20–22 have reported uses of conductive polymers, metals, CNT and carbon black to make conductive polymer composites; however they still suffer from poor thermal and electrical conductivity, and higher energy consumption. Therefore, it is desirable to use a conductive material that can provide excellent electro-thermal properties as well as can achieve desired temperature without compromising existing mechanical and thermal properties of composites.Currently, fibre reinforced polymer composites are increasingly popular in aerospace, automobile and civil engineering industries due to their higher strength and lower weight.2 carbon allotropes, has been focus of mass investigations in recent years due to its large surface area,23 record thermal conductivity,24 excellent mechanical strength,25 and superior electronic mobility.26 It has demonstrated much higher thermal conductivity ∼5000 W mK−1 than CNT (∼3000 W mK−1) and amorphous carbon (∼1 W mK−1).27 Previous study has demonstrated the use of graphene-based inks to produce highly conductive electrical conductor with lower resistance.28 Moreover, a small amount of graphene would be sufficient to form a percolative electric network due to higher aspect ratio and surface area;29 thus reduce overall weight of the composite. Recent studies have highlighted using of Graphene Nanoribbon (GNR),2,30 perfluorododecylated GNR31 and Graphene Nanoplatelets (GNP)32 for de-icing applications. However, there are number of problems still exist with these techniques such as complicated and expensive manufacturing route for GNR, not suitable for industrial applications and material waste. Moreover, strong van der Waals forces between graphene fillers may cause re-stacking in the polymer matrix, which may result in defective composites.33 Moreover, increased GNR concentration modifies the resin viscosity and increases the brittleness of composites.34Graphene, a single atom thick two-dimensional closely packed honeycomb lattice of spHere we report a scalable manufacturing route for next generation graphene-based de-icing composites. We utilise microfluidic exfoliation technique to synthesize graphene-based ink in a scalable quantity and use a dip-dry-cure coating technique to make highly conductive graphene-based glass fibre rovings. These graphene-coated glass rovings are characterised both electrically and thermally; then integrated into a composite structure. We demonstrate the use of as prepared composite for de-icing applications using Joule heating phenomena.2.2.1The natural flake graphite  was kindly supplied by Graphexel Limited, UK. Sodium deoxycholate (SDC) powder was purchased from Sigma Aldrich, UK. The glass fibre roving  was purchased from AGY (USA). 290 gsm (grams per square meter) plain woven glass fabrics, EL2 Epoxy Laminating Resin and AT30 Epoxy Hardener were purchased from Easy Composites, UK.2.228,35 Briefly, 50 g graphite powder and 10 g SDC are added into a glass bottle and mixed with 500 ml deionised (DI) water. This mixture is sonicated for 30 minutes using an ultrasound bath to allow homogenous dispersion and added into an input reservoir of a Microfluidizer . The dispersion is slowly passed through ‘Z-type’ microfluidic channels of ∼200 μm and ∼87 μm diameter with diamond construction at high pressure (∼200 MPa). This allows the exfoliation of graphite to few-layer graphene (FLG) at 100 ml min−1 flow under high shear rate [∼108 s−1] with a 100% exfoliation yield. The exfoliated dispersion is then passed through a cooling channel surrounded by cold water (∼25 °C) to prevent over-heating of the dispersion and collected. This process is repeated 20 times to produce FLG (MF flakes) which is then used as a conductive ink for glass roving coating.We use microfluidization technique to exfoliate graphene in a scalable quantity following previously reported methods.2.3We use a simple dip-dry-cure coating technique to coat glass fibre roving with graphene-based ink. The graphene-based ink is added into a 100 ml cylinder flask. Glass rovings are cut to 25 cm and dipped into graphene dispersion for 5 seconds. The coated glass fibre rovings are then passed through eyelets to squeeze extra ink out of coated glass tows and to maintain coating evenness. We then use a Mathis Laboratory dryer  to dry (at 100 °C) and cure coated glass fibres. We also use various curing temperatures , curing times (5 min to 30 min) and a number of coating cycles to optimise coating conditions.2.4We use vacuum resin infusion process and room temperature thermoset EL2 epoxy resin to manufacture de-icing composites that contains graphene-based (coated) glass rovings. Briefly, 6 layers of glass fabric (dimension: 10 × 10 cm) are laid on a pre-cleaned and pre-coated (with a release agent) metal plate. The graphene-based glass rovings are then inserted after 3 layers of glass fabric and connected to wires for electrical and thermal characterisation. The sample is sealed by a plastic bag and vacuumed pressed using a pump. EL2 Epoxy Laminating Resin and AT30 Epoxy Hardener are degassed separately for 30 minutes and mixed together immediately before we use. The resin with hardener is then flown over layered glass fabrics at a constant flow rate using a vacuum pump, which enables the impregnation of glass fabrics with resin. The resin infused preform is then cured at room temperature for 24 hours to make graphene-based glass composites for de-icing application.2.52 (290 nm oxide on plain silicon). The images and Raman spectra of MF flakes are taken at 10 different locations on the drop-casted sample to assess the flake size, flake thickness and flake types. We use an optical microscope to measure the flake size and Philip XL30 Field Emission Gun (FEG) Scanning Electron Microscope (SEM) to assess the surface topography of the untreated and coated glass rovings. A Dimension Icon (Bruker) Atomic Force Microscopy (AFM) is used to determine the flake thickness. A Renishaw Raman System equipped with 633 nm laser is used to collect Raman spectra of MF flakes, untreated and coated glass rovings. The surface of MF flakes, untreated and coated glass rovings is characterised using a Kratos Axis X-ray Photoelectron Spectroscopy (XPS) system. The thermal decomposition of graphite, SDC and MF flakes are evaluated using a TA instrument, TGA Q5000. The resistances of graphene-coated glass rovings per unit length are measured using a two probe multi-meter . The average resistance is calculated from 5 measurements at different positions along the length of graphene-based (coated) glass fibre rovings.The graphene-based dispersion containing MF flakes is diluted 1000 times and then drop-casted on Si/SiO2.6The electro-thermal behaviour of coated glass fibre rovings is measured using a thermal camera  and a power supply unit  which supplies direct current at different voltages from 0–30 V. The graphene-based glass fibre rovings are clamped on a wooden plate using two metals clamps at 1, 5, 15 and 20 cm distances. A multi-meter is also used to measure the current. The thermal camera is installed on a tripod and connected to the computer. The thermal images obtained by the camera is shown on the computer through a software . The change in temperature of the coated glass is observed and recorded at various volts and currents. Thermal images of coated glass at various volts and currents are also captured.3.3.1d < 100 μm) at high pressure (up to 209 MPa),35 which generates liquid velocities of 400 m s−1 and several order of magnitudes higher shear rates (>108 s−1)36 than conventional rotor-based or other homogenisers. It is used primarily for particle size reduction,37 nano-emulsion of immiscible liquids,38 for disrupting or lysing cells39–41 and de-agglomeration and dispersion of carbon nanotubes and graphene nano-platelets (GNP) into polymers.41,42 Recent studies have highlighted using microfluidization technique to produce graphene,28,35 graphene quantum dots36 and two-dimensional (2D) boron nitride nano-sheets.43 It is a simple and environmental friendly technique that can produce graphene-based ink with a 100% exfoliation yield.28 Moreover, this process could be scaled up to produce hundreds of kilos graphene-based inks, which would suit perfectly for industrial applications such as manufacturing of graphene-based multi-functional composites.We use microfluidization technique to exfoliate few layers graphene (MF flakes) from graphite into a water-based dispersion. Microfluidizer can pass fluids through micro-channels  scale" fill="currentColor" stroke="none"><path d="M0 440 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z M0 280 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z"/></g></svg>C bond in aromatic rings (∼284.6 eV),  of starting graphite above 750 °C; whereas MF flakes start to decompose at lower temperature (∼5.5 wt% up to 750 °C), may be due to the lower thermal stability of smaller MF flakes.44 As expected, SDC suffers significant decomposition around 400 °C.We use Graphexel 2736 grade graphite (average flake size < 50 μm) supplied by Graphexel, UK. 3.2For electro-thermal de-icing application, it is desirable to produce highly conductive and uniform glass-fibre roving using a scalable process. We use a very simple dip-dry-cure technique that could potentially be scaled-up for industrial applications. As illustrated in 45 However, after a certain temperature, further increase in temperature results in slight increase in the electrical resistance of graphene-based glass fibre roving. This optimum temperature point for lowest resistance varies with the curing time, as higher curing time provides lowest resistance at lower optimum curing temp and vice versa. We use 220 °C for 5 minutes as optimum curing condition to enable rapid drying and curing in a continuous manufacturing process. 2,46 Moreover, the contact resistance between graphene flakes are reduced with the increase of coating cycles. The lowest resistance of coated glass-fibre roving with graphene-based ink is obtained as ∼1.7 Ω cm−1 with 15 coating cycles.−1, ∼1582 cm−1 and ∼2700 cm−1, corresponding to D, G and 2D peaks, respectively. The D peak is caused by the defects and disorders in the hexagonal graphitic layers, while G peak attributed to an E2g mode of graphite due to the vibration of sp2-bonded carbon atoms in a two dimensional hexagonal lattice.47 These Raman spectra are similar to the spectra of a typical liquid-phase exfoliated graphene or graphitic materials.28,35,48 The wide scan XPS spectra of control glass-fibre reveal the presence of C1s, O1s, Si2s and Si2p and provide the evidence of some silane coating on the fibre surface, Raman spectra of control glass roving shows smooth featureless background of uncoated fibre, which is masked by strong fluorescence, C (284.6 eV) and C–O (286.4 eV), C, which is similar to graphene or graphite.49The high resolution C1s spectrum of control glass-fibre can be fitted into two main components: C–C/CSEM images provide further evidence of the presence of graphene flakes, covering the glass fibre, 3.3We use four different lengths  of graphene-based (coated) glass fibre rovings for electro-thermal characterisation and five samples for each length. We apply various voltages across the entire sample, and measure the current generated and the change in the temperature of graphene-based rovings (due to Joule heating) with voltages and the power consumed per unit length, I–V curves for various length of graphene-based glass roving show the linear relationship between the applied voltages and current passes through conductive rovings, p = IV/L), the curves for the samples of different length collapse on the same straight line indicating that the major dissipation mechanism is the thermal radiation and convection rather than thermal conductivity through the contacts. Moreover, thermal images show uniform heat distribution along the length of conductive graphene-based glass rovings . Moreover synthesis of GNR is based on complex, time consuming and expensive process of unzipping CNTs.50 Furthermore, GNR was mixed with epoxy resin which may alter the rheology and uniformity of epoxy/hardener mixture and limit the concentration of conductive materials.51 In contrast, we use a scalable process for manufacturing graphene-based glass roving. Moreover, the coating of individual glass roving with graphene-based ink would enable insertion of coated warp or weft glass roving into the fabric or composite structure as required. This would potentially reduce the material waste and provide much better control and flexibility to remove various amount of ice from different parts of the structure.In order to demonstrate a potential de-icing application of graphene-based glass rovings, we manufacture a glass–epoxy composite using a vacuum resin infusion process, where five graphene-based glass rovings are inserted in the middle of 6 glass fabrics layers (ESI, Fig. S4a and bFinally, we demonstrate the de-icing capability of our graphene-based glass/epoxy composites by dipping it into an ice-bucket, 4.−1 and efficient heating to a desired temperature at lower power consumption. We also demonstrate the use of this graphene-based glass rovings for manufacturing glass/epoxy composite for de-icing applications. The de-icing test shows efficient removal ice from graphene-based composite. We believe, the obtained results from this study would be an important step towards realising graphene-based next generation lighter, stronger and cost-effective smart de-icing composite for aerospace and other applications.We report a scalable process of manufacturing graphene-based surface heating for de-icing applications. The graphene-based glass roving demonstrates low resistance, ∼1.7 Ω cmThere are no conflicts to declare.RA-008-C8RA02567C-s001