Tectonics and climate-driven surface processes govern the evolution of Earth’s surface topography. Topographic change in turn influences lithospheric deformation, but the elementary scale at which this feedback can be effective is unclear. Here we show that it operates in a single weather-driven erosion event. In 2009, typhoon Morakot delivered ~ 3 m of precipitation in southern Taiwan, causing exceptional landsliding and erosion. This event was followed by a step increase in the shallow (< 15 km depth) earthquake frequency lasting at least 2.5 years. Also, the scaling of earthquake magnitude and frequency underwent a sudden increase in the area where mass wasting was most intense. These observations suggest that the progressive removal of landslide debris by rivers from southern Taiwan has acted to increase the crustal stress rate to the extent that earthquake activity was demonstrably affected. Our study offers the first evidence of the impact of a single weather-driven erosion event on tectonics. In turn, theoretical predictions and numerical models suggest that changes of surface topography by surface processes can promote tectonic deformation over geological times5 (1–10 Myr), enhance fault slip over intermediate time scales9 (1 kyr–1 Myr), and induce sufficient static stress changes over a seismic cycle  to trigger earthquakes10. However, the influence of ongoing surface processes on tectonics has not been directly observed. Over seasonal timescales, surface (un)loading induced by rainfall or snow can modulate local to regional seismicity13. Here we ask if a single erosional event can have a discernable effect on seismogenic processes, which dominate deformation of the Earth’s upper crust. Both large-magnitude earthquakes and extreme rainfall events can trigger instantaneous and widespread landsliding, driving the export of millions of tons of sediment from mountain areas over periods of months to years14. At these timescales, geophysical methods allow monitoring of changes in earthquake activity associated with erosional perturbations. Compared to large-magnitude earthquakes, rainfall events do not directly trigger aftershock sequences (even if surface (un)loading can modulate seismicity), which could preclude the observation of a seismicity change induced by erosion. We therefore focus in the following on detecting seismicity changes associated with an erosional perturbation induced by a rainfall event.It is well established that tectonics and climate influence the evolution of the Earth’s surface by modulating the rate and pattern of erosion and sedimentation15. The typhoon triggered more than 10.000 landslides (see “2 (hereafter the landsliding zone), that accounts for ~ 99% of the 1.2 km3 of total landslide volume16, the landslide spatial density ranges between 4 and 22 km-2  seismicity in Taiwan after it made landfall. Because the expected stress change is small compared to background tectonic loading at seismogenic depthion see “” sectionFirst, we assess the time evolution of earthquake statistics using a temporal sliding window of 1,001 earthquakes see “” sectionMoreover, the increase in earthquake frequency after Morakot is associated with an increase in the b-value from 1.18 ± 0.1 to 1.28 ± 0.1 Fig. a. Both iIn addition, considering all earthquakes during the 2.5 years before and after Morakot gives b-value estimates of 1.17 ± 0.03 and 1.31 ± 0.04 Fig. . CrucialThese temporal changes in earthquake statistics after Morakot are determined from an undeclustered earthquake catalog. However, using a declustered catalog see “” sectionTo assess how the chosen delimited area affects our results, we compute the change in the spatial pattern of the frequency and b-value of shallow (< 15 km) earthquakes from before to after Morakot. For this, we use a sliding window in space with a radius of 30 km, which allows us to detect large-scale features not affected by small sub-samples of events see “” sectionone Fig. . This in3 of landslides triggered by Chi-Chi earthquake25 being by far the largest, and because most landslides triggered by these events deposited debris distant from rivers14. Besides, the high rate of aftershocks after Chi-Chi prevents detection of a change in earthquake frequency or b-value associated with erosion due to Chi-Chi or Toraji, if there was any. We also note that the changes in earthquake frequency and b-value are not perfectly synchronous with typhoon Morakot and occur about 1–2 months after the typhoon. However, the time resolution of our temporal analysis does not allow us to detect with confidence changes occurring with a period less than about 100 days , and typhoons Herb (1996) and Toraji (2001) did not induce any detectable change of seismicity. This may be because these events had less erosion, the total volume of ~ 0.45 km26. The 4th of March 2010, the Mw 6.3 Jiashian earthquake occurred within the landsliding zone, close to its western limit, and was followed by many aftershocks. However, this earthquake and most aftershocks are located at 15–25 km depth  parts of faults33 and 2D elasto-dynamic models of seismogenic faults34 with rate-and-state friction laws36 show that the rate of seismicity can increase linearly or more than linearly due to a positive, step-like stress perturbation. It is also observed that shallow earthquakes generally have smaller magnitudes and larger b-values than deeper earthquakes37 possibly because they nucleate at lower differential stresses38. Our observations suggest that the intense and prolonged sediment export and surface unloading after typhoon Morakot could have acted as a progressive increase of stresses, with a complex spatio-temporal evolution, on the shallow parts of underlying thrust faults10, giving rise to a similar increase of shallow earthquake frequency and b-value in Southwest Taiwan.In addition, spring-slider models5 at the time scale of elementary processes. While numerous studies have shown that earthquakes and storms can trigger landslides25, this is to our knowledge the first potential evidence of the short-term and ongoing influence of erosion on seismicity. Because the mechanical link between erosion and stresses is through crustal elasticity10, crustal deformation is sensitive not only to extreme weather-driven erosion but also to the cumulative effects of smaller but numerous erosion events. More frequent extreme rainfall, for instance under a warmer climate39, could result in accelerated sediment transport19 and in turn in changes in the rate of shallow earthquakes, similar to the modulation of seismicity by surface water load variations13. Over the duration of the transient increase in seismicity, the shallow but small-magnitude seismicity induced by erosion is not likely to trigger new landslides, and the seismic moment rate would not be significantly affected. Hence, we do not expect a significant feedback of this additional deformation on erosion. However, the impact of this short-term transient signal on the seismicity and erosion over longer time scales, such as the duration of a seismic cycle, remains to be investigated. Our results therefore call for a new generation of process-based models coupling landscape dynamics21 and fault dynamics34 at scales relevant to natural hazards and societal issues. In these models, storms, floods, mass wasting, river sediment transport, redistribution of water, elastic stress transfer, seismicity and seismic wave propagation should all be represented to account for the complexity of the links between climate, erosion and tectonics.The proposed erosional-driven mechanism to explain the changes in seismicity after Morakot offers new perspectives on the links between climate, erosion and tectonicsThe map of cumulative rainfall during Morakot was obtained by natural-neighbor interpolation of cumulative hourly rain gauge measurements over the period 7 to 9th of August 2009. Data from 377 stations across Taiwan were used from the Data Bank for Atmospheric Research at the Taiwan Typhoon and Floods Research Institute.40 . To cover most of the islands we mosaicked multiple cloud-free pre-event  and post-event  images taken in 2009. For parts of the inventory, especially east of the main divide, landslides were first mapped automatically and then edited manually. For both approaches, the scar, runout and deposit areas are not differentiated. We did not consider debris flow transport areas and excluded gentle slopes (< 20°) from mapping to avoid confusion with human activity. Special attention was given to the separation of individual landslides, which had common transport or deposit areas but independent initiation points41. The robust and conservative estimation of landslide surface area is especially important for the estimation of landslide volume42.Mapped landslides were delineated manually by comparing surface reflectivity and morphology on pre- and post-event FORMOSAT-2 satellite images42. Then, we converted the scar area into volume using a power law with different prefactor . Most of the 0.75 GT of sediment export in 2009 from the Gaoping catchment, which drains a large area of the west part of the landsliding zone, can therefore be attributed to the impact of the landslides triggered by Morakot. Similarly, over the Island of Taiwan, suspended sediment discharge increased from about a mean of ~ 0.38 GT/year to ~ 1.1 GT/year in 2009, and a large part of this increase can be attributed to the impact of Morakot19. In 2010, suspended sediment discharge decreases to pre-Morakot values, partly due to the absence of large water discharge events. Timescales for bedload sediment export is probably much larger, between a few years to decades21 and potentially centuries. Most rivers connected to the landsliding zone experienced rapid and intense sediment aggradation, with 10–100 m of sediment thickness, in response to Morakot typhoon. To our knowledge, no study has been published on the regional evolution of this bedload sediment mass. The estimated total volume 1.2 km3 of landslides triggered by Morakot could translate in about 2.5–3 GT of sediments. It is therefore likely that about 20–30% of this mass was removed by suspended transport in 2009, and probably a few percent or more in the following years. Therefore, a rough estimate could lead to possibly 20–40% of sediment export over the time period 2009–2012. Adding bedload transport could hypothetically increases this estimate to 20–50% for the time period 2009–2012.There is currently no method allowing a robust and accurate measurement of sediment transport after typhoon Morakot, including suspended and bed loads, at the scale of Taiwan. Concerning suspended load, about 0.75 GT of sediments have been exported away in 2009 from the Gaoping catchment compared to an average ~ 0.02 GT/year over the period 1950–2008 . The monitoring network includes short-period and broadband seismographic systems stations. The location and number of seismic stations changed during the period 1995–2015. The configuration of the seismic network in the south of Taiwan and in the landsliding zone remained relatively similar over the period January 2007 to December 2012  from the earthquake catalogue of the Taiwan Central Weather Bureau45, where 46 of the b-value, 47, and that only relative spatial or temporal changes of the b-value should be interpreted.The Gutenberg–Richter distribution is classically used to characterize the relation of the number of earthquakes above a given magnitude, We use a temporal sliding window to subsample the earthquake catalogue and to assess time variations of earthquake statistical properties. Because the uncertainty of the b-value strongly depends on the number of considered events, and because larger samples give better estimates, we use a sliding window of 48, we compute the probability P that the earthquake frequency increases by a factor greater than r between a period 1 and 2,Following ref.49 between the 2.5 years before and after typhoon Morakot. We use a radius of 30 km for the sliding window, which enables sampling of a sufficiently large number of earthquakes at a length scale that is smaller than that of the landslide zone of 7,000 km2. The sampling window effectively corresponds to a disk shape extending to a depth of 15 km. The b-value is determined for the recorded earthquakes in each disk volume by maximum likelihood estimation. This method has an inherent statistical bias as the number of sampled earthquakes changes significantly depending on the local rate of seismicity. The minimum number of events for the determination of the b-value is set arbitrarily at 50. Our method can give rise to small-scale shapes in the maps of b-value, such as disk and rod shapes, that are not the focus of this study. We use a disk shape kernel with a radius of 15 km, convolved with the initial b-value map to blur the mapped patterns and to isolate features with longer wavelengths. More sophisticated methods exist to compute spatial variations of b-value, including a penalized likelihood-based method50 and a distance-dependent sampling algorithm51.We use a common spatial sliding window to subsample the earthquake catalogue and to assess variations of earthquake statistical properties in space52 and that will lead to method-dependent results. Yet, to test the impact of potential earthquake clustering on our results, we have applied the traditional Reasenberg declustering algorithm53, obtained from the ZMAP toolbox54, to the CWB earthquake catalog. This deterministic algorithm aims to remove earthquake sequences, defined as chains of connected earthquakes in space and time, leaving only the initial earthquake in a given sequence. We use standard parameters52 adapted for Taiwan with Several studies investigating potential earthquake frequency changes use declustered earthquake catalogs. However, declustering is an ill-posed problem that does not have a unique solution48. Under this potential limitation, this analysis demonstrates that earthquake clustering is not the reason for the observed changes after typhoon Morakot.Supplementary Figure 55: In addition, we are confident that large and deep mainshocks occurring in the landsliding zone, below 15 km, such as Mw 6.3 Jiashian earthquake in 2010, are not the cause for the observed seismicity changes. Indeed, declustering is efficient to remove most of the aftershocks caused by the Jiashian earthquake, which appear to be concentrated at depth between 15 and 30 km  using a time step of 1 s. It results that each synthetic catalog has the exact same magnitude distribution and average earthquake frequency than the true one, but the temporal distribution of earthquakes is randomly distributed. For each catalog (true or synthetic), the probability of frequency change and the change in b-value after Morakot are computed by comparing the earthquakes occurring in the 2.5 years after and before Morakot (see Supplementary Fig. Supplementary Figures


With the advent of Industry 4.0  came a paradigm shift built on core work-related skills that further dictated the emergence of a "new" world, with diverse professional disruptors and innovators at the forefront.,Co-curricular programs, which are out-of-classroom experiences, offered either independently from or in conjunction with the academic curriculum, hold a lot of potential for developing these key work-related attributes among students. Such programs can be based upon Kolb's Experiential Learning Theory (ELT), which is a pedagogical model, that entails a four-stage learning cycle of concrete experience, reflective observation, abstract conceptualization, and active experimentation.-On the basis of a deep-rooted institutional philosophy that "knowledge has no limits and hence learning should have no boundaries", the Mohammed Bin Rashid University of Medicine and Health Sciences (MBRU), Dubai, United Arab Emirates, developed and has been implementing a co-curricular program for medical students, based on Kolb's ELT and situated learning theory, called the MBRU-Summer Scholars Program (SSP). Since its inception in October 2017, the MBRU-SSP has been upholding the institutional vision and mission, and values' system, as well as complementing the spiral curriculum in the medical school. The key objective of the program is to provide a platform for students to acquire and integrate skills, knowledge, and competencies in research, clinical practice, community service, health systems, and/ or arts and culture domains. The program is characteristically diverse, giving participants the autonomy to select from an extensive array of offerings, thus setting MBRU-SSP apart from others which tend to focus on single domains.As part of the evaluation phase of the 2018/2019 MBRU-SSP cycle, quantitative and qualitative data was collected from three groups of stakeholders: participating students, onsite mentors, and program organizers. In general, all stakeholders appreciated the MBRU-SSP. Majority of the participating students rated the overall quality of the experience as excellent. The students found the program to be valuable to them as individuals , and to the community-at-large. Personal development, entailing character and resilience building, emerged as a significant benefit. Opportunities to apply previously acquired academic knowledge and expand students' professional network were highlighted. Students also conveyed that the impact of the MBRU-SSP extends to the community through the program's contribution to institutional advancement of MBRU and hosting centres. From the perspective of the MBRU-SSP organizers, the program objectives were achieved and contributed to the nurturance of global citizens. Onsite mentors expressed satisfaction with the overall organization of the program, as well as the attendance and level of engagement of the participating students.The MBRU-SSP represents a co-curricular program, grounded on holistic educational theories, which may serve as a so-called "first-aid kit" to humanize medical education, building on Flexner's legacy, and nurturing a future-ready doctor. The program fosters learning that occurs via individual adaption, along with participation in the real world and interaction with the wider society. It offers an example of a reproducible co-curricular program with positive impact on participants as individuals within the context of their interconnected communities.The authors declare that they have no conflict of interest.


Growth mindset is an important aspect of children’s socioemotional development and is subject to change due to environmental influence. Orchestral music education may function as a fertile context in which to promote growth mindset; however, this education is not widely available to children facing economic hardship. This study examined whether participation in a program of orchestral music education was associated with higher levels of overall growth mindset and greater change in levels of musical growth mindset among children placed at risk by poverty. After at least 2 years of orchestral participation, students reported significantly higher levels of overall growth mindset than their peers; participating students also reported statistically significant increases in musical growth mindset regardless of the number of years that they were enrolled in orchestral music education. These findings have implications for future research into specific pedagogical practices that may promote growth mindset in the context of orchestral music education and more generally for future studies of the extra-musical benefits of high-quality music education. Poverty and racism create gaps in opportunities for children to acquire the skills they need for success in school . RecentlPersistence may be particularly important for children placed at risk by poverty and racism, given that these children are more likely to face challenges over the course of their development . UnfortuThe past 20 years have witnessed the growing acknowledgment of the importance of children’s socioemotional development , a broadChildren who possess a growth mindset believe that the harder they work at something, the better they will be at it . AccordiAlthough mindset is sufficiently stable to be considered an aspect of personality, it is also dynamic across situations and malleable over time. Situational cues can lead children to adopt a growth orientation within a given context. Over time, repeated exposure to these cues can instantiate a growth mindset . It is nThe possibility that music education might promote extra-musical benefits is a controversial one. In general, the claims for the extra-artistic benefits of music and arts education have outpaced the evidence from rigorous research studies to support those claims . Many stspecific challenges that they must overcome on route to mastery. For example, the first time they play a D-major scale, many students learning a woodwind instrument are likely to play a C-natural rather than a C# because in the G-major scale (the one they are most likely to have learned prior to D-major) C-natural should be played.Although no study of which we are aware has examined the possibility that orchestral music education may promote children’s growth mindset, the process of learning an instrument includes a number of structural features that have been found to promote a growth orientation, as does the process of learning an instrument in an orchestral context. As sequential in that they occur in order of increasing difficulty, which allows children to monitor their progress toward mastery over time  would increase significantly over the course of the program year.In the current study, we assessed growth mindset among students participating in one of 12 El Sistema-inspired programs of music education for 1 (24%), 2 (17%), or 3 years (21%); comparison group students were recruited from the same schools and grades attended by the students in the programs. All students were in grades 3–5; the average age of the students was 10.2 years  in the United States over the course of 2 consecutive academic years. Students in cohort 1 participated in the study during the 2015–2016 academic year, whereas students in cohort 2 participated in the following academic year (2016–2017). Therefore, each student’s participation in the study lasted for one academic year. At the time of their participation in the study, 62% of students had been enrolled in one of 12 El Sistema-inspired programs and their host schools prevented us from collecting individual-level socioeconomic data about the participating students’ families. However, all but two of the 12 programs included in the study had income eligibility guidelines that required most or all of the families they served to be of low income. Moreover, as shown in Our memoranda of understanding with the El Sistema-inspired programs were required to offer instruction on an orchestral instrument to students in grades 3–5 (though they could serve students outside of this age range) and to offer that instruction weekly for a portion of the school year. The number of minutes of instruction per week and the number of weeks per year that instruction was offered varied, but on average, the programs offered 231.1 h of instruction per school year (SD = 105.1). All but two programs offered over 100 h of instruction per year, with hours of instruction offered by these programs ranging from 136 to 330. At each program, instruction was provided by teaching artists in a combination of small-group (string section) and large-group (orchestra) settings. One program, which was integrated into a music-focused charter school, offered instruction during the school day; the remaining programs took place after school.To be included in the study, At each program, a liaison was chosen in consultation with the study’s principal investigators and trained to lead data collection. Therefore, the liaison served in the role of a research assistant but was an employee of the program. The liaison was provided with a procedures manual as part of their training, which included a script to use when administering the measures. All students (those in one of the programs and those in the comparison group) completed the measure of overall growth mindset (see below) within 2 weeks of the beginning of the program year and again within 2 weeks of the end of the program year. Students enrolled in a program also completed the measure of musical growth mindset just after completing the overall growth mindset measure.These procedures were approved by the Institutional Review Board of Bard College, of which the Longy School of Music is a part.Students’ overall growth mindset was assessed using a variant of the six-item measure developed by Dweck and colleagues, which has been demonstrated to exhibit both concurrent and predictive validity in numerous prior studies . The meaEl Sistema-inspired programs that subsequently participated in the study. Students in the pilot study were of the same ages  and similar demographic composition to those who completed in the full study: 59% of the pilot participants were female, and 22.2% were identified as African American, 42% as Latino/Hispanic, 6% as Asian/Pacific Islander, 10% as White, 7% as mixed, and 4% as other. The adapted overall measure of growth mindset displayed acceptable internal consistency (α = 0.83), and, although the mean was high (3.10), there was good variability about the mean (SD = 0.67) and minimal evidence of skew . The measure of musical growth mindset, which was administered only to the subset of 72 students enrolled in an El Sistema-inspired program, displayed similar properties . Scores on the overall and musical growth mindset measures were correlated , suggesting that these two measures assessed related but distinct aspects of the common underlying construct of growth mindset.These measures were piloted in the academic year prior to the first cohort of students’ participation in the study, with a sample of 161 students recruited from 6 of the r(199) = 0.55, p < 0.001] and post-program  assessments  and post-program (α = 0.82) growth mindset scores were calculated as the mean of items (following reverse coding of appropriate items) for all students who answered at least 9 of the 10 questions. Parallel procedures were followed to calculate composite pre-program (α = 0.78) and post-program (α = 0.84) musical growth mindset scores. Composite overall and musical growth mindset scores were correlated at the pre-program . African American students reported significantly lower levels of overall growth mindset than their peers identifying as Latino/Hispanic or Asian/Pacific Islanders. Missingness of post-program musical growth mindset scores was not related to gender, ethnicity, age, program enrollment, or pre-program musical growth mindset scores. Missingness of post-program musical growth mindset scores was related to age , such that older students were more likely to be missing these scores. Therefore gender, ethnicity, and age were included as covariates in models estimating overall growth mindset, given that the distribution of enrolled and unenrolled students differed by gender (at a level approaching significance), ethnicity, and age and that ethnicity was related to overall growth mindset scores. Age was included as a covariate in the model estimating musical growth mindset.While gender was not related to post-program overall (p = 0.112) and child factors . Post-program overall growth mindset scores were estimated for the ith child in the jth program according to the following equation:A random-effects ANOVA was estimated to partition the variance in post-program growth mindset scores into portions attributable to program factors .p = 0.900), indicating that there was no difference in post-program overall growth mindset scores between students who were enrolled in the program and those who were not. However, the omnibus test of years  indicated that there were significant differences in post-program growth mindset scores as a function of students’ years of program enrollment . Tukey-adjusted contrasts indicated that, although there was no significant difference in post-program growth mindset scores between students who had been enrolled in the program for 1 year and those who had not been enrolled in the program, students enrolled in the program for 2 years exhibited significantly higher post-program growth mindset scores than students enrolled for 1 year or no years. Similar differences were observed between students who had been enrolled for 3 years and those enrolled for 1 year or no years (see The specific contrast between students who were not enrolled in the program (years = 0) and those who were [years = ] was not significant , between-child , and between-program  portions. Musical growth mindset scores were estimated for the ith timepoint for the jth student enrolled in the kth program according to the following equation:Given that measures of musical growth mindset were collected only from students enrolled in a program, our model was parameterized so that the wherein time is a categorical variable with two levels: 0 = pre-program and 1 = post-program.B = 0.09, t(272) = 3.02, p = 0.003], indicating that musical growth mindset scores increased over the course of the program year. Model-implied estimates indicated that, on average, pre-program score was 3.16 (SE = 0.03), while post-program score was 3.25 (SE = 0.03), corresponding to an effect size of d = 0.32. To examine whether the degree of residualized change in musical growth mindset scores varied as a function of the number of years students had been enrolled in the program, the model specified in Eq. 2 was re-estimated after introducing the interaction between time and years. As in Eq. 1, the variable years was a categorical variable but, in this case, had only three levels, given that comparison-group students did not complete the musical growth mindset measure. The parameter estimate for the interaction term was not significant (p = 0.190).The parameter estimate for time was statistically significant and positive [El Sistema-inspired program of orchestral music education might predict significantly higher levels of overall growth mindset and increases in musical growth mindset among children at risk.The prospect that orchestral music education might promote growth mindset is both exciting and controversial. It is exciting because growth mindset matters for all children and particularly for those who face the risks associated with poverty and racism that inculcate cognitive  and neurEl Sistema-inspired program of orchestral music education was associated with higher levels of overall growth mindset. After controlling for key demographic variables and initial growth mindset scores, students participating in a program showed higher levels of growth mindset than their peers who did not participate. Although this finding is consistent with a growing body of evidence that high-quality and intensive music education programs may be linked to extra-musical benefits , it would allow for the possibility of isolating the specific effect of music education on growth mindset.This possibility underscores one limitation of our study: the inability to draw causal inference. Students in our study (or possibly their families) self-selected to participate in an per se, it is also important to note that our sample was comprised entirely of students from the United States. This means that key components of the context in which the El Sistema-inspired programs included in the study operate may not be found in other countries. For example, although extra-curricular arts education programs are at least partially subsidized by the government in much of the developed world, in the United States, they are funded primarily through donations from individuals, corporations, and private foundations. As a result, disruptions in revenues due to economic events (such as the 2008 recession) can undermine the capacity of these programs to provide continuous instruction. Thus, the context in which orchestral music education occurs in the United States may differ from the context in which it occurs in other countries, just as the broader context in which development unfolds differs. These differences may together restrict the generalizability of the findings reported here to children raised in other countries and contexts.While not a limitation may—while these structural features of orchestral instruction may imbue it with the potential to foster growth mindset, whether that potential is realized is undoubtedly influenced by the approach to teaching employed by a particular program or instructor. All else being equal, a program that instilled an ethos of cooperation and ensemble achievement among its students would be more likely to maximize opportunities to overcome corporative goals than a program that encouraged competition and focused on the success of some students to the exclusion of others.The final limitation of the present study is its emphasis on the structural, rather than the pedagogical, features of orchestral music education. As we noted above, all the programs included in our study shared certain structural features, such as a combination of small- and large-group instruction. Some of those structural features may foster students’ growth mindset, and some of those features—such as placing students in orchestras at an earlier point in their musical development than is generally the case and emphasizing sectional and full-ensemble rehearsals over private instruction—may be particularly effective in fostering growth mindset by offering opportunities to pursue corporative goals. However, at this point, emphasis must be placed on Perhaps the most important aspect of pedagogy as it relates to growth mindset is the nature of the feedback teachers provide to students. Making mistakes is an essential part of learning an orchestral instrument. If a teacher works with a student to acknowledge and reflect on their mistakes in way that focuses on the potential for improvement, it can foster that student’s growth mindset , but it Sistema-inspired orchestral music education. These observations revealed that teachers’ feedback to students featured high levels of language about the value of effort and persistence ’ legal guardian/next of kin for the publication of any potentially identifiable images or data included in this article.SH, JB, and DW designed the study. ES oversaw the data entry and management and assisted SH with the statistical analyses. SH prepared the initial draft of the manuscript, to which all authors subsequently made contributions.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.


We identify a decidable synthesis problem for a class of programs of unbounded size with conditionals and iteration that work over infinite data domains. The programs in our class use uninterpreted functions and relations, and abide by a restriction called coherence that was recently identified to yield decidable verification. We formulate a powerful grammar-restricted (syntax-guided) synthesis problem for coherent uninterpreted programs, and we show the problem to be decidable, identify its precise complexity, and also study several variants of the problem. Program synthesis is a thriving area of research that addresses the problem of automatically constructing a program that meets a user-given specification , 21, 22.A classical stream of program synthesis research is one that emerged from a problem proposed by Church  in 1960 In recent years, the field has taken a different turn, tackling synthesis of programs that work over infinite domains such as strings , 20, intIn this paper we present, to the best of our knowledge, the first decidability results for program synthesis over a natural class of programs with iteration/recursion, having arbitrary sizes, and which work on infinite data domains. In particular, we show decidable synthesis of a subclass of programs that use uninterpreted functions and relations.uninterpreted programs. Uninterpreted programs work over infinite data models that give arbitrary meanings to their functions and relations. Such programs satisfy their assertions if they hold along all executions for every model that interprets the functions and relations. The theory of uninterpreted functions and relations is well studied—classically, in 1929, by Gödel, where completeness results were shown [coherent programs, was identified and shown to have a decidable verification problem. Note that in this verification problem there are no user-given loop invariants; the verification algorithm finds inductive invariants and proves them automatically in order to prove program correctness.Our primary contribution is a decidability result for realizability and synthesis of a restricted class of imperative e shown  and, more shown . In recee shown , a subclgrammarany data model that gives meaning to function and relation symbols.In this paper, we consider the synthesis problem for coherent uninterpreted programs. The user gives a straight-line programs !Our primary result is that the realizability problem (checking the existence of a program conforming to the grammar and satisfying its assertions) is decidable for coherent uninterpreted programs. We prove that the problem is Coherence of programs is a technical restriction that was introduced in . It consNote that automatic synthesis of correct programs over infinite domains demands that we, at the very least, can automatically verify the synthesized program to be correct. The class of coherent uninterpreted programs identified in the work of  is the on, by using a set of Boolean variables linear in n and requiring a loop body to strictly increment a counter encoded using these variables, we can demand that loops terminate in a linear/polynomial/exponential number of iterations. We can also implement loops that do not always terminate, but terminate only when the data model satisfies a particular property, e.g., programs that terminate only on finite list segments, by using a skeleton of the form:. Grammar-restricted program synthesis can express the synthesis of programs with holes, used in systems like Sketch [SyGuS (syntax-guided synthesis) format [The problem of synthesizing a program from a grammar with assertions is a powerful formulation of program synthesis. In particular, the grammar can be used to restrict the space of programs in various ways. For example, we can restrict the space syntactically by disallowing while loops. Or, for a fixed  Sketch , where t format , 521.all program trees of coherent programs that satisfy their assertions. Given a grammar in the size of the grammar. We also prove a matching lower bound by reduction from the acceptance problem for alternating exponential-space Turing machines. The reduction is non-trivial in that programs (which correspond to runs in the Turing machine) must simulate sequences of configurations, each of which is of exponential size, by using only polynomially-many variables.The proof of our decidability result relies on tree automata, a callback to classical theoretical approaches to synthesis. The key idea is to represent programs as trees and build automata that accept trees corresponding to correct programs. The central construction is to build a two-way alternating tree automaton that accepts rams in  and adaprams in  for builRecursive Programs, Transition Systems, and Boolean Programs: We study three related synthesis problems. First, we show that our results extend to synthesis of call-by-value recursive uninterpreted programs . This problem is also transition systems. Transition systems are similar to programs in that they execute similar kinds of atomic statements. We allow the user to restrict the set of allowable executions (using regular sets). Despite the fact that this problem seems very similar to program synthesis, we show that it is an easier problem, and coherent transition system realizability and synthesis can be solved in time exponential in the number of program variables and polynomial in the size of the automata that restrict executions. We prove a corresponding lower bound to establish We next examine a synthesis problem for Finally, we note that our results also show, as a corollary, that the grammar-restricted realizability/synthesis problem for Boolean programs (resp. execution-restricted synthesis problem for Boolean transition systems) is decidable and is  Sketch .Due to space restrictions, we present only proof gists for main results in the paper. All the complete proofs can be found in our technical report .We will begin by looking at several examples to gain some intuition for uninterpreted programs.hole ‘n), but is not allowed to refer to uninterpreted functions, and thus the program we are looking for is an uninterpreted program. For such a program, the assertion all models, i.e, for all interpretations of enc and dec and for all initial values of the program variables Consider the program in Fig. otocols , 16.then-branch is taken and set else-branch is taken. Program synthesis requires a control-flow independent decision to be made about how to fill the hole. In this sense, we can think of the hole as having only incomplete information about the executions for which it must be correct. This can be used to encode specifications using complex ghost code, as we show in the next examples. In Sect. transition system synthesis, where holes can be differently instantiated based on the history of an execution.The program in Fig. In this example, we model the synthesis of a program that checks whether a linked list pointed to by some node x has a key k. We model a ghost code into the program skeleton; we distinguish ghost code fragments by enclosing them in. The skeleton in Fig. while-loop and the second hole ‘while-loop need to be filled so that the assertion at the end is satisfied. We use three ghost variables in the skeleton: Our formalism allows only for entclass1pt{minimacheck that the answer coherent [Now, notice that the skeleton needs to oherent  and hencall possible ways to fill the holes (thus including the solution above) and it is therefore possible to enumerate and pick specific solutions. It is straightforward to formulate a grammar which matches this setup. As noted, we must stipulate that the holes do not use the ghost variables.In fact, our procedure will synthesize a representation for unrealizable: for a list with multiple locations having the key other location with key Consider the same program skeleton as in Example We can encode input/output examples by adding a sequence of assignments and assumptions that define certain models at the beginning of the program grammar. For instance, the sequence of statements in Fig. We can similarly use special variables to define the output that we expect in the case of each model. And as we saw in the ghost code of Fig. (grammar-restricted) uninterpreted program synthesis problem.In this section we define the syntax and semantics of uninterpreted programs and the Syntax. We fix a first order signature V be a finite set of program variables. The set of programs over V is inductively defined using the following grammar, with f and R of the appropriate arities), and V is clear from context, we will omit the subscript V from Program Executions. An execution over V is a finite word over the alphabetcomplete executions for a program p over V, denoted partial executions is the set of prefixes of complete executions in executions, and clarify as needed when the distinction is important.ge. See  for a stSemantics. The semantics of executions is given in terms of data models. A data model U and an interpretation function U at the end of p, any particular data model corresponds to at most one complete execution on  and T. It generates programs with a conditional that has the same number of assignments in the input grammarFor example, we disallow the grammar in Fig. p is correct. The synthesis problem is to determine the above, and further, if realizable, synthesize a correct program Given an input grammar Consider the program with a hole from Example mentclass2pt{minimSince verification of uninterpreted programs with loops is undecidable , 42, theThe uninterpreted program synthesis problem is undecidable.We next consider synthesizing loop-free uninterpreted programs (for which verification reduces to satisfiability of quantifier-free EUF) from grammars conforming to the following schema:The uninterpreted program synthesis problem is undecidable for the schema straight-line uninterpreted programs . An execution coherent if it satisfies the following two conditions.rograms ). An exeMemoizing. Let Early Assumes. Let p is coherent if every complete execution A program The following theorems due to  establis([). The verification problem for coherent programs, i.e. checking if a given uninterpreted coherent program is correct, is decidable.. The ve([). The problem of checking coherence, i.e. checking if a given uninterpreted program is coherent, is decidable.. The prThe techniques used in  are autox and z, respectively, but the term is dropped after the second statement and hence is not contained in any program variable when the third statement executes. Next consider program w and z, namely To give some intuition for the notion of coherence, we illustrate simple example programs that are not coherent. Consider program n  of state, incoming direction, and node labels to positive Boolean formulas over pairs We now discuss the construction of the two-way alternating tree automaton T as input, T and explores all the executions of the associated program. For each execution The automaton n  Sect. . The basWe now give the formal description of States. Both the full set of states and the initial set of states for Transitions. For intuition, consider the case when the automaton’s control is in state q reading an internal tree node n with one child and which is labeled by conjunctive transition of the two-way alternating automaton. That is, i, m, a, we have For every Transitions from the Root. At the root node, labeled by m is set to Transitions from Leaf Nodes. For a leaf node with label q, the transition of the automaton is a in Transitions fromNodes. As described earlier, when reading a node labeled by m of the state. That is, no matter how the program arrives at a Transitions fromNodes. At a node labeled up to an q remains unchanged:Transitions fromNodes. In this case, the automaton moves either to the left child, the right child, or to the parent, depending on the last move. It does not change the state component. Formally,Now consider the case when the automaton moves The following lemma asserts the correctness of the automaton construction and states its complexity.tree automaton The rest of the synthesis procedure goes as follows. We first construct a nondeterministicts from , 53 ensuThis gives us the central upper bound result of the paper. in the size of the input grammar. Furthermore, a tree automaton representing the set of all correct coherent programs that conform to the grammar can be constructed in the same time.    The grammar-restricted synthesis problem for uninterpreted coherent programs is decidable in alternating Turing machines (ATMs) with exponential space bound [Our synthesis procedure is optimal. We prove a mentclasspt{minimae bound .The grammar-restricted synthesis problem for coherent uninterpreted programs is In this section, we give results for variants of uninterpreted program synthesis in terms of transition systems, Boolean programs, and recursive programs.Here, rather than synthesizing programs from grammars, we consider instead the synthesis of transition systems whose executions must belong to a regular set. Our main result is that the synthesis problem in this case is Transition System Definition and Semantics. Let us fix a set of program variables V as before. We consider the following finite alphabetcheck letters.TS over V is a tuple Q is a finite set of states, A (deterministic) transition system  executionV is a finite word over the induced execution alphabet If Otherwise We define the semantics of a transition system using the set of executions that it generates. A complete execution is an execution whose corresponding final state  using two regular languages S and R. Executions must belong to the first language S (which is prefix-closed) and all complete executions must belong to the second language R. A specification is given as two deterministic automata TS and specification automata TS satisfies its (syntactic) specification. Note that this need not entail correctness of TS. Splitting the specification into partial executions S and complete executions R allows us, among other things, to constrain the executions of non-halting transition systems.. Given a finite set of program variables V and deterministic specification automata correct, coherent transition system TS over V that satisfies the specification. Furthermore, produce one if it exists.complete information of past commands executed at any point. We will observe in this section that the transition system synthesis problem is Since programs are readily translated to transition systems (of similar size), the transition system synthesis problem seems, at first glance, to be a problem that ought to have similar complexity. However, as we show, it is crucially different in that it allows the synthesized transition system to have P from Example P with either P executes, there are two different executions that lead to the hole. In grammar-restricted program synthesis, the hole must be filled by a sub-program that is executed no matter how the hole is reached, and hence no such program exists. However, when we model this problem in the setting of transition systems, the synthesizer is able to produce transitions that depend on how the hole is reached. In other words, it does not fill the hole in P with uniform code. In this sense, in grammar-restricted program synthesis, programs have incomplete information of the past. We crucially exploited this difference in the proof of To see the difference between program and transition system synthesis, consider program skeleton is (see ). No sucTransition system realizability is decidable in time exponential in the number of program variables and polynomial in the size of the automata Here we observe corollaries of our results when applied to the more restricted problem of synthesizing Boolean programs.nondeterminism with a special assignment b nondeterministically to T or F. As usual, a program is correct when it satisfies all its assertions.In Boolean program synthesis we interpret variables in programs over the Boolean domain T and F. Each nondeterministic assignment is modeled by computing a T or F. Since uninterpreted programs must satisfy assertions in all models, this indeed captures nondeterministic assignment. Further, every term ever computed in such a program is equivalent to T or F  emerged as a uniform technique to solve such synthesis problems against temporal logic specifications with optimal complexity bounds [finite program trees, using two-way traversals to simulate iteration. The work in [The automata and game-theoretic approaches to synthesis date back to a problem proposed by Church , after w bounds , 44, 45. bounds  that worwork in , howeverWhile decidability results for program synthesis beyond finite data domains are uncommon, we do know of some results of this kind. First, there are decidability results known for synthesis of tranducers with registers . Transdusatisfiability games [Another setting with a decidable synthesis result over unbounded domains is work on strategy synthesis for linear arithmetic y games . There iTree automata techniques for accepting finite parse trees of programs was explored in  for syntThe work in  explorest paper  exploresWe presented foundational results on synthesizing coherent programs with uninterpreted functions and relations. To the best of our knowledge, this is the first natural decidable program synthesis problem for programs of arbitrary size which have iteration/recursion, and which work over infinite domains.The field of program synthesis lacks theoretical results, and especially decidability results. We believe our results to be the first of their kind to fill this lacuna, and we find this paper exciting because it bridges the worlds of program synthesis and the rich classical synthesis frameworks of systems over finite domains using tree automata , 32, 48.axioms  and yet preserve decidability of verification. The methods used therein are compatible with our technique, and we believe our results can be extended smoothly to their decidable settings. A more elaborate way to bring in complex theories (like arithmetic) would be to marry our technique with the iterative automata-based software verification technique pioneered by work behind the Ultimate tool [complete synthesis procedures.Turning to practical applications of our results, several questions require exploration in future work. First, one might question the utility of programs that verify only with respect to uninterpreted data domains. Recent work  has showte tool –26; thisThe second concern for practicality is the coherence restriction. There is recent work by Mathur et al.  that sho


Natural immunoglobulin M (IgM) antibodies are pentameric or hexameric macro-immunoglobulins and have been highly conserved during evolution. IgMs are initially expressed during B cell ontogeny and are the first antibodies secreted following exposure to foreign antigens. The IgM multimer has either 10 (pentamer) or 12 (hexamer) antigen binding domains consisting of paired µ heavy chains with four constant domains, each with a single variable domain, paired with a corresponding light chain. Although the antigen binding affinities of natural IgM antibodies are typically lower than IgG, their polyvalency allows for high avidity binding and efficient engagement of complement to induce complement-dependent cell lysis. The high avidity of IgM antibodies renders them particularly efficient at binding antigens present at low levels, and non-protein antigens, for example, carbohydrates or lipids present on microbial surfaces. Pentameric IgM antibodies also contain a joining (J) chain that stabilizes the pentameric structure and enables binding to several receptors. One such receptor, the polymeric immunoglobulin receptor (pIgR), is responsible for transcytosis from the vasculature to the mucosal surfaces of the lung and gastrointestinal tract. Several naturally occurring IgM antibodies have been explored as therapeutics in clinical trials, and a new class of molecules, engineered IgM antibodies with enhanced binding and/or additional functional properties are being evaluated in humans. Here, we review the considerable progress that has been made regarding the understanding of biology, structure, function, manufacturing, and therapeutic potential of IgM antibodies since their discovery more than 80 years ago. During humoral immune responses, immunoglobulins of the IgM, IgD, IgG, IgA, and IgE isotypes may be produced, each expressing a unique profile of effector functions capable of mediating host defense against invading pathogens. Macro-immunoglobulin, IgM, is initially produced as a surface bound molecule and is expressed in early B cell differentiation. Later in the immune response, IgM is produced by plasma cells and secreted as soluble pentamers that contain 10 antigen binding sites and the joining (J) chain, or as hexamers containing 12 antigen binding sites and no joining chain (J-chain). IgM has a molecular weight of approximately 900 or 1050 kDa for the pentamer or hexamer, respectively .Due to the polyvalent nature of IgMs, they may exhibit higher avidity for antigen than the bivalent IgG. In addition to neutralizing pathogens, IgM antibodies are highly effective at engaging complement to target lysis of cells and pathogens.Our understanding of the biology, structure, and function relationships for IgM antibodies has progressed to the point where this antibody isotype can be exploited therapeutically; however, challenges associated with their manufacture remain. Here, we review the progress and the therapeutic potential for this class of antibodies, as well as the potential for new classes of engineered IgM antibodies.Humoral immunity has been studied since the late 1800s when George Nuttall . The firXenopus, are hexameric in structure even though Xenopus IgM has been reported to contain a J-chain [Immunoglobulins, including IgM antibodies, are found in all jawed vertebrates (gnathosomes) that diverged in evolution from jawless fish (agnathans) approximately 550 million years ago ,9. Simil J-chain . In cont J-chain ,16. It i J-chain . In addi J-chain ,19. Inte J-chain . In fact J-chain  and unpu+ multipotent progenitors differentiate into common lymphoid precursors (CLP) that give rise to both B and T cell lineages. CLPs subsequently differentiate into early pro-B cells that express Igα and Igβ, essential signaling components of the B cell receptor (BCR). Initiation of the µ heavy chain (µHC) locus rearrangement occurs during the transition to pro-B cells when the RAG1/2 recombination complex induces rearrangement of the D to JH gene segments and, subsequently, to the V to DJH gene segments. However, no surface µHC is expressed until the cells differentiate into large pre-B cells that express a pre-BCR composed of a µHC complexed to surrogate light chains VpreB and λ5 chain. Signaling through the pre-BCR results in the proliferation, differentiation, and subsequent surrogate light chain downregulation, paving the way for λ or κ light chain rearrangement to form surface IgM with different antigen specificities [In mammals, B cell development occurs in a hierarchical, ordered manner in fetal liver during embryonic development, and then in bone marrow and peripheral lymphoid tissue in adults. Within bone marrow, CD34ficities . Receptolow IgDhigh in the follicles and IgMhigh IgDlow in the marginal zone of the spleen. B-1 cells also mature into IgMhigh IgDlow cells. Although the variable domains of the IgM and IgD are identical, alternative transcription and splicing results in both IgM and IgD heavy chains [Within the spleen, IgM expressing immature B cells begin to express surface IgD, which separate into the following different populations: IgMy chains . These py chains ,27,28,29During human fetal development, IgM can be detected in the serum at approximately 20 weeks of gestation . In cont“Natural IgM” antibodies represent the majority of secreted IgM antibodies found in normal serum and are also located in the pleural and peritoneal compartments ,38. ThisThe source of natural IgM antibodies is somewhat controversial. In mice, natural IgM antibodies are reported to be produced by B-1 cells residing in the bone marrow and spleen ,43,44,45One of the roles of natural IgM antibodies includes the targeting of altered self-antigens or neo-epitopes on dying cells for targeted removal, thereby maintaining tissue homeostasis . One sucIn addition, natural IgM antibodies have been demonstrated to play a role in controlling B cell development, selection, and induction of central tolerance to prevent autoimmunity. The rare condition of selective IgM deficiency in humans, although associated with recurrent infections, is characterized by an increased risk of developing autoimmune diseases such as arthritis and systemic lupus erythematosus . In a stUpon binding to antigen, the BCR expressed on naïve follicular B cells is activated and B cells exit the follicle, proliferate, and produce relatively short-lived IgM secreting plasmoblasts in lymphoid tissues . In the However, IgM production is not limited to just the initial antigen response. In fact, IgM-expressing memory B cells have been identified that have V region mutations suggesting that these are post germinal center B cells ,60. AnalThe interaction of IgM antibodies with antigens can dramatically enhance humoral immune responses to the antigens beyond that of IgG. This is exemplified by studies that have evaluated the co-administration of IgG or IgM with xenogeneic erythrocytes in murine models . When IgIgM antibodies also play key roles in mucosal defense. Secondary lymphoid tissues containing B and T cells, referred to as mucosa-associated lymphoid tissues (MALT), are associated with multiple organ systems including the gastrointestinal and respiratory tracts. These secondary tissues are less organized than primary lymphoid tissues. As discussed below in further detail, the J-chain of pentameric IgM antibodies interacts with the polymeric immunoglobulin receptor (pIgR) on cells which results in the transcytosis of the antibodies from the circulation and through epithelial cells to mucosal surfaces to provide a first line defense against pathogens . The J-cAntibodies of the IgM isotype are typically found as pentameric or hexameric in format, where each monomer is approximately 190 kDa, comprised of a heavy µ chain with five domains  and a light chain with two domains (Vκ-Cκ or Vλ-Cλ) . IgM conHuman immunoglobulin heavy chain constant domains are shown in As shown in In addition to the heavy chain and light chains, IgMs also possess a third chain, a polypeptide of 137 amino acids, known as the joining (J)-chain, which is a key feature of polymeric IgA and pentameric IgM antibodies ,79. The Antibodies are glycoproteins with N-linked glycosylation. In the case of IgG, there is N-linked glycosylation at Asn 297, which influences binding to Fc gamma receptors, and hence has a role in modulating antibody-dependent cell-based cytotoxicity (ADCC). Significantly, IgMs have more sites of glycosylation as compared with that of IgG. Whereas IgG heavy chains have a single glycosylation site, human and non-human primate IgM heavy chains exhibit five N-linked glycosylation sites at Asn 171 (Cµ1), Asn 332 (Cµ2), Asn 395, Asn 402 (both in Cµ3), and Asn 563, which is in the heavy chain tailpiece . An addiThe additional sites of glycosylation increase the complexity of IgM antibodies. Detailed site-specific carbohydrate analysis of IgM demonstrates that not all of the N-linked sites are similarly glycosylated. N-linked glycosylation has various levels of complexity, from high mannose or simple glycans to bi-, tri- and tetra-antennary complex glycans. Interestingly, the three sites at Asn 171, Asn 332, and Asn 395  exhibit complex carbohydrate moieties with sialylated termini. However, the more carboxy terminal sites at Asn 402 and Asn 563 (in domains 3 and 4) contain high mannose structures . This paThe nearly mega dalton size of a fully assembled IgM complex has proven to be a challenge for determining a detailed structure. However, informative and useful models of IgM were initially created using a combination of techniques including low resolution cryo-electron microscopy, X-ray crystallography, NMR-derived structures of the subdomains, and homology modeling.In some of the earliest studies ,88, threInterestingly, although the mu chain tail pieces and the J-chain are known to play critical roles in the assembly and function of IgM antibodies, for many years, the three-dimensional structures within the IgM pentamer have largely remained elusive. In fact, until recently, only a secondary structure for the J-chain has been proposed . ImportaNatural IgM antibodies, in conjunction with natural killer (NK) cells, dendritic and mast cells, and macrophages are part of the innate immune system, the first line of defense against invading microorganisms and aberrant human cells , as well as complement dependent cytotoxicity (CDC). In contrast, IgM does not bind the Fc gamma receptors, and therefore does not exhibit ADCC. However, IgMs have very potent CDC activity. Their hexameric or pentameric structure allows highly avid binding of complement component C1q to IgM, and therefore IgMs are able to fix complement substantially better than IgGs  see Fig. Recent IgM antibodies are known to bind to multiple receptors, which are illustrated in J-chain containing polymeric immunoglobulins such as IgA and IgM are often found on mucosal surfaces associated with a peptide called the secretory component (SC). The SC peptide is a proteolytic fragment of a cell surface receptor responsible for transport of polymeric Igs from the apical to mucosal surfaces . The polStructurally, pIgR belongs to the IgG superfamily with five Ig-like domains (D1–D5) that are heavily glycosylated see . Hinge rThe crystal structure of domain 1 (D1) of pIgR reveals a structural similarity to the variable domain of Ig that contains a highly conserved helix with a region that is implicated in binding to IgM . The D1 The Fcα/µ receptor was identified in a screen of receptors from a cultivated mouse lymphoma cell line capable of binding IgMs. This receptor is approximately 70 kDa in size, belongs to the immunoglobulin superfamily, and is extensively glycosylated. The Fcα/µ receptor is localized to all lymphoid tissues including lymph nodes and the appendix, and is also widely expressed in non-lymphoid tissues including kidney and intestine, with lower expression observed in the lungs, liver, and myocardium . ResidueThe most recently identified receptor interacting with IgM is FcµR, which is a transmembrane sialoglycoprotein of approximately 60 kDa . FcµR, aThe need for scalable production processes will grow as the therapeutic interest in the use of IgM antibodies increases. IgMs have been considered to be difficult to express, due to their large size and complexity see , resultiBiotherapeutic proteins, in general, including immunoglobulins, can be expressed in a variety of expression host cells . MammaliThe manufacture of IgM molecules for early clinical trials was done using hybridoma cells derived from rat or mouse myeloma cells or a heteromyeloma between human lymphoid cells and murine myeloma cells (see Table 3 in The purification of IgM for Good Manufacturing Practice (GMP) manufacturing has not been able to take advantage of affinity resins such as Protein A, which has been the standard recovery method for IgG. IgM does not bind to protein A. However, other affinity resins are available and are quite useful for research scale purification but are not currently available for scale-up with an associated GMP-compliant regulatory support file. IgMs also appear to have a narrower range of conditions under which they remain soluble as compared with IgGs, which can present difficulties in purification. Although low pH steps can be used for viral inactivation with IgMs, detergent-based approaches are more commonly used for viral inactivation in IgM downstream processing.Early methods for purification of IgMs have included isoelectric precipitation and gel chromatography . These iIn 2007, a three-step purification strategy for IgM antibody molecules was presented at a conference on purification of biological products . The invLarge scale GMP manufacture of IgM products is possible with a variety of traditional columns. New mixed-mode resins also may provide even greater capabilities. In 2011, at an IgM meeting in Germany, GE Healthcare reported on the use of layered beads in which the inner core was functionalized and the outer core was inert and porous . This leAs has been well demonstrated with IgG antibodies, IgM antibodies also have the potential to provide therapeutic benefit in humans. Indeed, IgM antibodies have been shown to be efficacious in a variety of animal models, including non-human primates  and wereCurrently, there are hundreds of therapeutic IgG antibodies that have advanced to clinical trials, and more than 90 antibody-based products have achieved FDA approval . HoweverTaken together, the studies described below demonstrate that IgM antibodies can be safely administered to humans. However, the IgM antibodies tested to date have not typically produced sufficient efficacy in humans to obtain (or maintain) regulatory approval. This result is likely due to the fact that most, if not all, of the IgM antibodies tested were of natural origin and, as a consequence, essentially contained germ-line gene sequences that have not undergone extensive somatic mutation, and thus were of low affinity and specificity . It is aShown in TM (nebacumab) received regulatory approval in Europe in 1992. However, this approval was withdrawn in 1993, following the inability of subsequent trials to demonstrate a clinical benefit [Five of the IgM product candidates  in  benefit .Pseudomonas aeruginosa LPS antibodies was tested in normal adults and in patients with P. aeruginosa bacteremia [P. aeruginosa LPS IgM originally developed by Kenta  [Around this same time, several additional clinical trials were initiated with other anti-LPS antibodies. Chiron initiated a Phase 1 trial with MAB-T88, and reported that it was safe and well tolerated . A seconcteremia . This cobacumab) , in patibacumab) , but morbacumab) . Similarbacumab)  or are ibacumab) , using IWhile the above results are, at first, discouraging, it is also now clear that many of the issues associated with the anti-LPS IgM mAb trials likely reflect the difficult nature of this clinical indication   as well Another three IgMs, in MORAb-028 is an IgM that targets ganglioside GD2 licensed from Micromet and originally designated MT228. MORAb-028 entered two Phase 1 clinical trials in 2010, one for intratumoral injection  and one rHIgM22 binds to a complex myelin proteolipid antigen that is only expressed in CNS white matter and has been reported to promote remyelination in animal models . It was Despite the fact that IgM antibodies are well suited to target repetitive antigens , very feOn the basis of these results, a recombinant human IgM variant of mAb216, termed IGM-55.5, was generated. The antigen recognized by both mAb216 and IGM-55.5 on human B cells is a linear lactosamine epitope that is sensitive to the enzyme endo-beta-galactosidase. This ligand, termed “cell death inducing molecule” (CDIM), is similar to the “i” antigen of cord blood red blood cells ,164. TheInterestingly, IgM antibodies of this class often have heavy chain variable regions encoded by the human Vh4-34 V region gene , and thePatrys Ltd. in Australia was one of the first companies to focus on investigating the therapeutic potential of natural human IgM antibodies, and two of the candidates tested clinical target glycan-based epitopes. PAT-SC1, originally isolated by Peter Vollmers and colleagues at the Institute of Pathology at the University of Würzburg  targetedTM (fanolesomab-Tc99m) is a radioimmunodiagnostic agent consisting of a murine IgM monoclonal antibody labeled with technetium-99m (99mTc). Fanolesomab is directed against the carbohydrate moiety 3-fucosyl-N-acetyl lactosamine that defines the cluster of differentiation 15 (CD15) antigen (NeutroSpecTM package insert) [TM received FDA approval for scintigraphic imaging of patients with equivocal signs and symptoms of appendicitis who were five years of age or older. However, the product was suspended in 2005 following reports that patients taking the drug suffered serious and life-threatening cardiopulmonary events. NeutroSpecTM was subsequently discontinued in 2008.Lastly, NeutroSpec insert) . The CD1 insert)  and, in One of the first IgM antibodies to be tested clinically was Campath-1M. This antibody, which recognized the lymphocyte antigen CD52, was an IgM mAb isolated by Herman Waldmann and colleagues from rats immunized with human lymphocytes . Early c®  for B cell chronic lymphocytic leukemia [Ultimately, Campath-1M was first class-switched to a rat IgG2b (Campath-1G) , and theleukemia .In addition to Campath, four other IgM antibodies to protein antigen targets have been tested in clinical trials. Two of these IgM mAbs are of mouse origin , one is chimeric (ARG098) and one is human (Mab 16.88). ABX-CBL (murine hybridoma-derived IgM) and TOL101 target human CD147 and the αβ T cell receptor, respectively. ABX-CBL was tested in patients with steroid-refractory acute graft-versus-host disease (aGvHD) at doses up to 0.3 mg/kg/day . Among 5TOL101 targets the human αβ T cell receptor and was tested in renal transplant patients. Interestingly, in an effort to minimize T cell activation and its consequences that were observed with higher affinity IgG antibodies, this IgM was explored as a lower affinity/lower avidity therapeutic targeting this antigen. In a Phase 2 study , patientARG098 is a mouse/human chimeric IgM antibody that targets FAS receptor and was tested in subjects with rheumatoid arthritis. Unlike the other IgM antibodies discussed here, ARG098 was administered via intraarticular injection into the knee at very low doses (up to 10 µg per knee). As ARG098 exhibited evidence of clinical activity, a placebo-controlled Phase 2a study was initiated and the program was partnered with Centocor, however trials were apparently discontinued in 2015 .Lastly, 16.88 is a human IgM antibody that was derived from colorectal cancer patients immunized with autologous tumor cells admixed with BCG . Of releIn 1964, Barth and colleagues published one of the first articles examining the pharmacokinetics (PK) of normal, unaltered human IgM antibodies in humans . The IgMThe pharmacokinetics of several therapeutic IgM mAbs have also been studied in some of the clinical trials described in Combined, these differences make direct comparisons of the reported data quite difficult, not only between trials but also with the published data for normal human IgM. However, despite these differences it is encouraging to note that IgM antibodies can have relatively long half-lives in humans, thereby allowing weekly or bi-weekly dosing in the clinic.As indicated in n = 398), the total number of subjects treated with IgM antibodies was more than 1800 patients.Of the IgM antibodies listed in The observations that several human IgM antibodies have been safely administered in the clinic are particularly encouraging, given the theoretical concern that multivalent, high-avidity antibodies may exhibit off-target binding that could result in unexpected toxicities or rapid clearance. In some of the IgMs isolated as naturally occurring antibodies to tumor targets, there may be low affinity binding with high avidity which may contribute to unexpected, off-target binding. In the clinical studies reported to date, no such concerns have been raised. However, these concerns can only be addressed by further development and clinical testing of additional IgM antibody product candidates.In addition to the more traditional IgM antibodies, a number of new molecular constructs have been generated that seek to approximate the hexameric structure of the IgM molecule. One such class of molecules, the HexaBody™, was generated by introducing mutations in the IgG heavy chain that allow oligomers up to hexamers form in a concentration-dependent fashion on the surface of cells . The mosAs our understanding of expression systems and manufacturing of IgM antibodies progresses, we anticipate the utilization of IgM as a new modality of engineered antibodies for treatment of various therapeutic indications. Most importantly, IgM has 10 or 12 binding sites and is capable of binding its antigen targets with high avidity. For cell surface targets where there is repetitive display on a cancer or other target cell, high avidity allows for multiple antigen engagements per IgM. As a consequence, IgMs are particularly well suited for targeting difficult antigens. In some earlier IgM-based development efforts , antibodGiven the greater valency of IgM, these macromolecules offer considerable opportunity for higher order cross-linking of cell surface receptors. In addition, the flexibility of the IgM may provide the appropriate architecture for binding multiple targets on a cell surface. The potential for IgM-induced multimerization of cell surface targets makes the IgM an ideal candidate platform for developing TNF receptor superfamily agonists. For example, IgM antibodies directed to death receptor 4  have shoMany of the earlier programs that tested IgM in human clinical trials used natural IgM antibodies often isolated from patients or humanized from a murine hybridoma. However, there is significant opportunity for more engineered versions of IgM, where the variable domains of an affinity matured IgG can be grafted onto IgM constant domains. This “domain swap” of affinity matured variable domains from IgG onto the backbone of IgM can lead to marked increases in binding avidity and potency of an engineered IgM. As a platform for engineering oligomeric binding units, IgM offers a much wider variety of multimeric interaction with antigens.Although engineering of antigen binding sites can yield novel IgM constructs with improved antigen binding, there also exists additional unique sites on IgM for adding multispecific binding. For example, bispecific IgG antibodies and other bispecific variants of IgG exhibit extremely potent tumor targeting agents . HoweverOne such antibody, IGM-2323, is an anti-CD20 x CD3 IgM with “10 × 1” bispecificity (10 binding sites for CD20 and one binding site for CD3ε) . This noWith renewed focus on IgM antibodies and the engineering of IgM antibodies, there may well be advantages inherent to the IgM platform that can yield improved biotherapeutic agents for treatment of unmet medical needs. The recently published three-dimensional structure of IgM Fc pentamer may also allow better understanding of this complex macromolecule . We anti


Objectives: Falls are the leading source of accidental injury and hospitalization among adults over the age of 65. Relative to people with intact cognition, individuals with cognitive impairment are at increased risk for falls; however, few falls prevention programs exist to specifically reduce and prevent falls in this population. To address this issue, we developed a novel, multifactorial, cognitively-based falls prevention program, Stepping Out. Based on the popular and effective evidenced-based program, Stepping On, Stepping Out was modified and tailored to the learning needs of individuals with Mild Cognitive Impairment (MCI). We hypothesized that older adults with MCI would find the program understandable, and that program participants would demonstrate reduced falls. Methods: Sixteen veterans, mean age of 77.5, diagnosed with MCI and at increased risk for falls participated in Stepping Out. Falls were collected for the six months prior to intervention and the six months during and after program participation. All participants completed post-program evaluations. Falls incidence was compared using a Wilcoxon paired signed rank test. Results: Stepping Out was found to be feasible and comprehensible by all participants. Program participants exhibited significantly reduced falls, with median reduction of two falls (p = 0.0020), and a range of zero to 12 falls. Discussion: With appropriate modifications, individuals with MCI were able to benefit from a cognitively-based falls prevention program and to reduce accidental falls incidence. Falls are an important and feasible target to address among individuals with cognitive impairment.


We previously showed that ergosterol has an inhibitory effect on bladder carcinogenesis. In this study, we aimed to elucidate the molecular mechanism by which ergosterol inhibits bladder carcinogenesis using a rat model of N-butyl-N-(4-hydroxybutyl)nitrosamine-induced bladder cancer. The messenger ribonucleic acid (mRNA) expression level of the cell cycle-related gene cyclin D1 and inflammation-related gene cyclooxygenase-2 in bladder epithelial cells was significantly increased in the carcinogenesis group compared with the control group. In contrast, in ergosterol-treated rats, these increases were significantly suppressed. Ergosterol did not affect the plasma testosterone concentration or the binding of dihydrotestosterone to androgen receptor (AR). The mRNA expression levels of 5α-reductase type 2 and AR were higher in the carcinogenesis group than in the control group but were significantly decreased by ergosterol administration. These results suggest that ergosterol inhibits bladder carcinogenesis by modulating various aspects of the cell cycle, inflammation-related signaling, and androgen signaling. Future clinical application of the preventive effect of ergosterol on bladder carcinogenesis is expected. Bladder cancer is one of the most common urological tumors. It mainly affects men, with an incidence approximately 10 times higher in men than in women . TreatmePolyporus sclerotium, Alisma rhizome, Poria sclerotium, Donkey glue, and aluminum silicate hydrate with silicon dioxide. We clarified that among these components, Polyporus sclerotium has the strongest inhibitory effect on bladder carcinogenesis  5α-dihydrotestosterone  was purchased from GE Healthcare Bio-Sciences Corp. .Ergosterol and sodium saccharin (SS) were purchased from Wako Pure Chemicals . Male 5-week-old Wistar rats were obtained from Japan SLC, Inc. . The care and handling of the animals were in accordance with the Hoshi University .A short-term carcinogenicity study was performed according to a previous method  10,12].,12.10,12g for 15 min at 4 °C), and the plasma was stored at −80 °C until the assays were performed. Free testosterone was obtained by centrifugation  using an ultrafiltration device . The plasma concentrations of total and free testosterone were enzymatically quantified using the Testosterone EIA kit.Blood samples were centrifuged , and the radioactivity of [3H]-DHT was then measured in a liquid scintillation counter .Maltose binding protein-fused human AR ligand-binding domain , -DHT, and the extent of [3H]-DHT exclusion from AR was evaluated.We investigated whether ergosterol competitively inhibits the binding of AR and DHT. Specifically, ergosterol was added in the presence of AR and [3H]-DHT from AR. On the other hand, this exclusion effect was not observed with ergosterol  is involved in mediating the increases in cyclin D1 and COX-2 expression during carcinogenesis ,30, and Testosterone is metabolized to the active metabolite DHT by 5α-reductase and then binds to AR and exerts an androgenic effect. Flutamide, which has antiandrogenic activity, dose-dependently decreases the incidence of carcinogenesis in the rat model of BHBN-induced bladder carcinogenesis . In addiThe results of this study clarified that ergosterol inhibits bladder carcinogenesis by modulating various aspects of the cell cycle, inflammation-related signaling, and androgen signaling. Reports have indicated that (1) high expression of cyclin D1 after TUR treatment shortens the time to recurrence in humans , (2) COX