Spartina alterniflora recovered more slowly. Faunal communities, including nekton and birds, were largely unaffected by sediment placement. Overall, sediment placement provided Ninigret Marsh with an estimated 67–320 years of ambient elevation gain, increasing its resilience and likely long-term persistence. Project stakeholders intentionally aimed for the upper end of high marsh plant elevation growth ranges to build elevation capital and minimize maintenance costs, which also resulted in new migration corridors, providing pathways for future marsh expansion.Heightened recognition of impacts to coastal salt marshes from sea-level rise has led to expanding interest in using thin-layer sediment placement (TLP) as an adaptation tool to enhance future marsh resilience. Building on successes and lessons learned from the Gulf and southeast U.S. coasts, projects are now underway in other regions, including New England where the effects of TLP on marsh ecosystems and processes are less clear. In this study, we report on early responses of a drowning, microtidal Rhode Island marsh  to the application of a thick (10–48 cm) application of sandy dredged material and complimentary extensive adaptive management to quickly build elevation capital and enhance declining high marsh plant species. Physical changes occurred quickly. Elevation capital, rates of marsh elevation gain, and soil drainage all increased, while surface inundation, die-off areas, and surface ponding were greatly reduced. Much of the marsh revegetated within a few years, exhibiting aspects of classic successional processes leading to new expansive areas of high marsh species, although low marsh  Coastal salt marshes are transitional habitats that occur between uplands and estuaries and provide ecosystem services and societal benefits. They serve as habitat for fish, shellfish and wildlife, maintain water quality, and sequester carbon , and dur−1, but in the near-term  this increased 68% to 4.78 mm yr−1 , reduced sediment supplies, and coastal development, accelerated SLR is now leading to rapid marsh change and degradation . The higvia regrowth of existing plants through the new sediment. A growing body of literature demonstrates beneficial results from TLP including enhanced elevation capital and vegetation biomass via reduced inundation, better drainage, and increased redox potential  were added to a low-elevation, drowning marsh in a microtidal coastal lagoon in southern RI. We hereafter deviate from using the term “TLP” in favor of “sediment placement” due to the thickness of sediment added to the marsh in this study. Dredged sediments were a product of a coupled effort to dredge and deepen a channel within an adjacent breachway to improve navigation for recreational boaters. The project was conducted using a coordinated consortium of policy analysts, restoration practitioners, and coastal researchers representing local, state, and federal government agencies, nonprofits, and universities .The primary goals of the project were to restore high marsh species to portions of the marsh that had been degraded due to prolonged surface water ponding, and increase marsh resilience to future SLR using targeted sediment placement . The oveThe 15-ha study site is located within the coastal barrier complex along the southern edge of Ninigret Pond in Charlestown, RI . NinigreSpartina alterniflora, and high marsh consists of Spartina patens, Distichlis spicata, and Juncus gerardii, with Iva frutescens and invasive Phragmites australis found at higher elevations near the upland. An 8.9-ha subsection of the overall study site exhibits signs of SLR and inundation stress including large areas of marsh platform die-off, in both low and high marsh. Die-off areas are distinct from natural pools and pannes in that they are shallow impounded surface depressions containing combinations of bare peat, open water, stunted vegetation, and filamentous algae , and is bordered at the upland edge by I. frutescens/J. gerardii and P. australis. The marsh is unditched with a small number of remnant pools on the marsh platform. The control marsh is also exhibiting SLR stress including stunted vegetation, waterlogged soils and expanding marsh surface die-off areas , with gradual slopes extending out to existing marsh elevations. This was to facilitate drainage and avoid shallow-water ponding on the marsh surface at low tide.The project concept was developed by the RI Coastal Resources Management Council in partnership with the Town of Charlestown, Save The Bay, Salt Ponds Coalition, and the U.S. Fish and Wildlife Service. Project design was driven by restoration goals and construction considerations, with key drivers being the estimated volume of material needed to achieve target elevations to promote desired marsh plant species and build elevation capital, and the volume of material contained within the areas to be dredged. The study site was segmented into marsh restoration “units” for design purposes, which were designed to have higher elevations at their centers  was 17.78–25.40 cm NAVD88, and 25.44–30.48 cm NAVD 88 for I. Frutescens . Maximum target elevations were then increased by 2.54 cm to account for anticipated compaction of existing sediment under placed sediment based on bulk density measurements of existing marsh soil cores  were planted in low marsh, high marsh, and higher-elevation habitats to facilitate revegetation. Combining all species, approximately 80 planted areas were established across the marsh in 2017, totaling ~1.4 ha  were planted at higher elevations, and fencing installed, to trap wind-blown sediments and limit sediment loss into existing channels. Prior to the first growing season, ~235 m of creeks (45-cm deep and 60-cm wide) were excavated with a low ground-pressure excavator to restore tidal hydrology in the sediment placement area, with significant grading required to stabilize creekbank slopes. Runnels  in September 2017 and then spot treated in fall 2018. Additional areas were targeted for herbicide treatment in 2018 where P. australis established after sediment placement. Existing creeks were maintained by removing sand that filled the creeks from lateral erosion or from the new marsh surface via wind, and by regrading and planting creek banks with S. alterniflora to help stabilization. To drain groundwater and impounded freshwater along the upland border of the marsh and discourage P. australis colonization, additional elevation adjustments were made via excavator-grading and new runnels were excavated. Runnels were also dug in lower elevation areas to drain salt water impounded by the marsh-peat sill along the edge of the sediment placement area. All told, 235 m of new creeks and 1760 m of new runnels were excavated or hand dug after sediment placement at the impact site. An additional 0.15 ha of plugs were planted in 2018.Another period of adaptive management began in July 2017 and continued for approximately 16 months through 2018. Activities during this phase included P. australis pulling.After approximately three growing seasons, as vegetation recolonization increased and hydrology began to stabilize, adaptive management became less frequent. Beginning in 2019, such activities were generally limited to hand maintenance of existing creeks and runnels and additional Our general approach was to monitor ecological parameters in the study marsh before and after sediment placement to quantify change over time and use similar monitoring data from the control marsh to account for natural levels of interannual change to isolate changes in the study marsh due to sediment placement  and digital elevation models were created. The surveys were standardized for comparisons with each other by creating equal-resolution DEMs (61-cm pixel size) and clipping the extents of each DEM with a single polygon. One survey of the control site was conducted in winter 2018 using the same methods as at the impact site in 2018. The 2018 surveys of both sites included the collection of a single elevation point from the center of each plot established for vegetation monitoring and, to compare with pre-sediment placement, elevation from the center of each impact marsh plot in 2014 was estimated from interpolation as described above.Elevation surveys of the impact site were conducted in 2014 (before sediment placement) by the Town of Charlestown, and in 2017 (immediately post sediment placement) and 2018 by the University of RI after adaptive management activities. Surveys were conducted on the ground using survey-grade  GNSS receivers (2014) and a robotic total station (2017 and 2018). The total station surveys were initiated from benchmark locations derived from GNSS observations. Thus, all topographic data have comparable accuracies (centimeter). All topographic data were referenced to the RI State Plane Coordinate System NAD 83 (2011) (FIPS code 3800) with vertical coordinates referenced to the North American Vertical Datum of 1988 (Geoid 12B). The 2014 survey had an average point spacing of 3,030 pts haIn addition to broad-scale mapping, finer-scale elevation changes were monitored at three locations in each site using deep-rod surface elevation tables SETs; . In the To develop a local tidal datum and calculate mean high water (MHW) applicable to both the impact and control sites, a HOBO U20-001-04 water level logger (Onset Corp.) was deployed from March 30 - September 24, 2018 in the coastal pond adjacent to the impact site and programmed to record water height above the sensor every 6 min. The logger was housed in a PVC tube (which was mounted to a cinder block that was pinned with stainless steel rods driven 1 m into the substrate) and attached to the end of a PVC housing cap. Geodetic height of the sensor was determined by GNSS surveying of a target mounted to the top of the cap, ensuring that measurements were always taken from the same location. Water height above the sensor was also measured during deployment and periodically over the 6-month period to serve as an accuracy check and account for movement and pressure-sensor drift. Tidal datums for the deployment period were calculated by using the Tidal Analysis Datum Calculator (NOAA CO-OPS). Values were converted to NAVD88 using the mean of GNSS measurements on the mount target at deployment and retrieval. These tidal datums represent conditions specific to the deployment period and have not been tied into a long-term control station.1) the uncapped well top to the marsh surface, and 2) the well top to the sensor were measured and used to calculate marsh surface inundation  and drainage (percent of time water was lower than 5 cm below the marsh surface).To examine interannual patterns in marsh surface inundation and drainage, water heights were monitored annually at two random locations in each marsh for approximately 1 month each summer using HOBO loggers (same model as above) deployed in PVC wells. Each 0.75-cm long × 20-cm diameter well was perforated with 6-mm holes for drainage and sunk into the marsh until 10 cm remained above the marsh surface. Loggers were suspended to a fixed depth near the bottom of each well and programmed to collect overall pressure data (converted to water depth by compensating for ambient barometric pressure) every 15 min. At the beginning of each deployment, distances (cm) from In August 2015 (pre-sediment placement) and 2019 (post-sediment placement), twenty permanent plots (10 in each site) were sampled to assess soil % moisture, bulk density, % organic matter, and belowground biomass . Plots were selected along the existing vegetation monitoring transects to be representative of the marsh landscape including low and high marsh zones. A McCauley peat sampler was used to collect samples to a depth of 25 cm at the control and impact sites in 2015, and the peat sampler was again used in 2019 at the same plots at the control site. A combination of soil pits (to sample the added sediment) and peat sampler (for collecting from the underlying peat) were used at the impact site in 2019. Core and soil samples were stored in a freezer until processing and laboratory analyses.Defrosted soil cores were cut in 5-cm increments, and wet and dry weights were used to calculate % moisture and bulk density, respectively. To determine organic matter and carbonate content, unsieved sediment samples were dried, ground with a mortar and pestle, and subsamples were weighed into crucibles (~5 mg) for loss on ignition . Dried sSoil shear strength was measured vertically with depth directly adjacent to vegetation monitoring plots within 2 h of low tide to allow for comparisons of marsh soil strength at similar tide heights between sites. Marsh soil strength reflects the resistance to shearing stresses afforded by the cohesion and frictional resistance of soil constituents and is presumed to be an indicator of soil matrix integrity in salt marshes . A field2 plots located equidistant along the transects  at the height of the growing season in 2015 and 2016 before sediment placement and annually thereafter through 2020. None of the plots at the impact marsh were in areas that were planted with vegetation as part of adaptive project management. On each date, cover of vegetation species and other features  was quantified in each plot in both marshes using the point intercept method with 50 points per plot  were randomly measured for length. Stem density and mean length measures were used to estimate aboveground biomass using stem length–biomass regression analyses generated from samples harvested from the study sites in 2015 (next section).Five or six monitoring transects were established at each marsh. Transects spanned the entire marsh platform from open water to the marsh/upland ecotone. Vegetation was monitored in 1 mper plot  and conv2 quadrats for S. alterniflora and P. australis and 0.1 m2 quadrats for S. patens, J. gerardii, and D. spicata were used to harvest representative samples of each species at the impact and control sites in 2015. A total of 25 quadrats (five per species) were collected at each site. Individual stem length and dry weight were measured and used in regression analyses to determine a specific stem length-biomass relationship for each species  were sampled in the impact and control sites using 1 mFour bird survey points in the impact site were selected using a generalized random-tessellation stratified (GRTS) sampling system in package “spsurvey,” program R . Eight sField surveys followed the North American Marsh Bird Monitoring Protocol  to collet-test was used to compare monitoring plot elevations in the impact marsh before (interpolated 2014 data) and after (2018 RTK data) sediment addition, and Kruskal-Wallis one-way ANOVA on ranks was used to compare these two sets of data with the control marsh in 2018. To explore patterns in marsh elevation change rates from SETs before and after sediment placement, we calculated mean pin height from each SET on each sampling date in both marshes. Means were first calculated separately for each of the four SET arm directions, and then averaged across arms.A Paired A three-factor ANOVA model  was used to examine differences in moisture fraction, bulk density, and % OM. When the three-factor interaction term was significant at alpha 0.05, pairwise comparisons between sites were year and depth-specific, and pairwise comparisons between years were site and depth-specific, with Bonferroni adjustment made due to the five depth-specific comparisons. Two-factor models were used for the analysis of belowground biomass (year and site factors) and 2019 carbonate fraction (site and depth), using log-transformed data. Prior to carbonate data analysis, half the minimum value observed was added to each value to eliminate zero valued results.To analyze soil shear strength, two depth increments  were examined: 10–30 cm and 40–60 cm. The 10–30 cm interval is the usual depth associated with root and rhizome activity and the 40–60 cm zone is the sub-rooting depth . Only deFor most analyses, bare and open water cover were summed into an aggregate “unvegetated cover” category because we were interested in total revegetation responses. Although, for cover ANOVA analyses only, bare and open water were also examined individually to explore specific aspects of recovery.S. patens, D. spicata, J. gerardii), successional colonists , selected individual plant species, bare ground, open water, and total unvegetated using transect mean percent cover values in a two-factor ANOVA with time and site factors. The model included an evaluation of the site × time interaction term, consistent with the BACI design. The time factor was broken out with pre-sediment placement as years 2015 and 2016, and each post-sediment placement year evaluated separately. This differential treatment of years allowed us to examine vegetation trajectory over time after sediment placement, and pre-sediment placement years at both sites allowed for examination of natural, interannual variability. Evaluating the significance of the site × time interaction allowed us to assess whether a significant change over time occurred at one site, but not the other, as well as whether the impact site differed from the control site each year after sediment placement. When the interaction was significant, time comparisons were done by comparing the site-specific pre-sediment placement category separately with each post-sediment placement year for that site, but not directly comparing post-sediment placement years to each other, using Bonferroni correction among site/time combinations. When the interaction was not statistically significant, the main effects of time and site were examined.Cover analyses were performed for total plant cover, dominant two species per plot, high marsh dominants  were examined to assess change over time at each site, before and after sediment placement. Statistical analyses generally followed the same model approach and time categorization used for vegetation cover analyses. As with cover data, stem density and biomass were analyzed based on comparisons using transect means; however transect means were calculated using natural log(x+1) transformed count/biomass values. Since P. australis was so infrequently detected on vegetation transects at the impact site, a presence/absence evaluation was used in addition to transect mean analyses, using a logistic regression model. For this comparison, separate models were fit using indicator variables  for each post-sediment placement year, and for interaction terms between year and site. Models were then fit with and without the time/site interaction terms, and with and without the time variables, and used likelihood ratio Chi-Square tests comparing models to evaluate overall significance of the interaction and of the time factor.Stem density and aboveground biomass of five dominant plant species  to identify species or cover classes that contributed most to overall community similarity each year in each marsh. Finally, metric multidimensional scaling (MDS) was used to visualize spatial patterns of vegetation communities within and among years in both marshes using bootstrap average analysis on Bray-Curtis similarity matrices; group averages were calculated from  regions .etc.) described above for vegetation were also used to test for changes in nekton and bird communities over time and between sites, using the interaction term to identify changes at the impact site related to sediment placement. The only difference is that nekton data were fourth-root transformed prior to analysis to dampen effects of extremely abundant species ; bird count data were square-root transformed.The same multivariate analyses , and mummichog (Fundulus heteroclitus) densities, which had fewer zeros, were analyzed using two-factor ANOVA and Normal score transformation . A time-series plot was also created to visualize changes in total nekton density and total nekton population size  over time at both sites. For each species/station/year, mean density from the July and September sampling periods was used for all nekton analyses.Nekton and crab burrow densities typically had high frequencies of zeros and were therefore analyzed using logistic regression models with significance of the two factors and their interaction evaluated using Likelihood Ratio Chi-Square tests. However, total nekton, sheepshead minnow (Log(x+1) transformed bird count data were analyzed using two-factor ANOVA (site and time) with pairwise time comparisons conducted using Bonferroni correction. Bird species and guild densities in the impact and control sites were also estimated for each survey year from the raw count data using the package “unmarked” in R using a generalized multinomial N-mixture model (the “gmultmix” function) . Each spvia natural colonization and plantings. By 2019, the third growing season after sediment placement, much of the impact site had re-vegetated  with a mix of saltmarsh, pioneer, brackish, and upland salt-tolerant species, and by 2020 the majority of the site was vegetated, with very little exposed sand  of the marsh was at elevations above MHW  of the marsh was above MHW; by 2018 the site gained slightly more elevation capital, with 96% of the marsh  above MHW. Surface elevations in vegetation monitoring plots in 2018 averaged 0.22 m MHW (range of −0.08 to 0.35 m MHW) at the impact site and 0.03 m MHW (range of −0.16 to 0.13 m MHW) at the control site. Plot elevations at the impact site before sediment placement in 2014 averaged 0.003 m MHW (range of −0.15 to 0.18 m MHW). Plot elevations were significantly higher after sediment placement at the impact site compared to initial conditions  and when comparing all three sets of plot elevation data, control site elevations in 2018 were not significantly different than the impact site before sediment placement, but were significantly lower than the impact site after sediment placement .Sediment placement was effective for raising the elevation of the impact marsh surface and increasing elevation capital relative to water levels, with enhanced elevations appearing stable after 3 years. From the survey before sediment placement, only 44%  and the overall rate in the nearby control marsh . This high rate, however, was likely due to unconsolidated sand movement on the new marsh because the mean rate of elevation gain in the impact marsh from spring 2019 through fall 2020, when the marsh revegetated and appeared to stabilize, was only −0.84 mm yr−1.Finer-scale changes in elevation were discernible from SET monitoring, which also demonstrated a large increase in elevation capital immediately after sediment placement, and enhanced rates of annual elevation gain thereafter. Impact marsh elevation increased by a mean of 227 mm (range = 120–320 mm) across the three SETs from 2016 to 2017 . In the via winter northerly winds.The overall increase in elevation after sediment placement was lower than optimal due to below-ground subsidence. Marker horizon readings in fall 2018 showed that a mean of 284 mm of sediment (range = 187–344 mm) was added to the impact marsh as of October 2018. From SET readings, the mean net elevation increase during this same time period was 221 mm (range = 141–304 mm), indicating that mean below-ground subsidence was 63 mm (range = 40–103 mm). Subsidence was apparently due to sediment placement on existing degraded peat. The largest post-sediment placement elevation increases were measured in spring (2018 and 2019) at the SET nearest the open pond. This was also the only SET with rapid vegetation regrowth, suggesting that vegetation trapped unconsolidated sediments from the project that were moving Sediment placement altered hydrology of the marsh surface and uppermost sediment layers, eliciting a shift from prolonged inundation and persistent soil waterlogging before sediment placement to greatly-reduced inundation and enhanced drainage after. Data from HOBO loggers deployed in wells within marsh soils show that the percent of time the impact marsh surface was inundated with tidal water decreased from 49% before sediment placement  to 2% after sediment placement . Belowgrp = 0.0221) (p = 0.0252). Impact site bulk density in 2019 (mean ranging from 1.19 g ml−1 at 5 cm to 0.93 g ml−1 at 25 cm) was significantly greater than at the control (mean ranging from 0.15 g ml−1 at 5 cm to 0.56 g ml−1 at 25 cm) for all depths except 25 cm. At the impact site, bulk density in 2019 was significantly greater than 2015 (mean ranging from 0.28 g ml−1 at 5 cm depth to 0.67 g ml−1 at 25 cm) at 5 and 10 cm only, while at the control there was no difference in bulk density between 2015 and 2019 for any depth.Sediment placement altered impact site sediments, which became drier with higher bulk density and a lower fraction of organic matter and root biomass. There was a significant three-factor  interaction for percent soil moisture ( 0.0221) . At the p = 0.0022) for soil organic matter fraction. At the control site, there was no difference in organic matter fraction between 2015 (0.34 ± 0.06) and 2019 (0.32 ± 0.04), but at the impact site, organic matter fraction in 2015 (0.21 ± 0.06) was significantly greater than 2019 (0.05 ± 0.01). In 2019, control site organic matter fraction was significantly greater than the impact site. There was also a significant two-factor site × year interaction (p = 0.0032) for root biomass (to a depth of 25 cm). While there was no difference between 2015 (8008 ± 1409.5 g m−2) and 2019 (3266 ± 682.8 g m−2) at the control site, root biomass was significantly greater in 2015 (4475 ± 765.9 g m−2) than 2019 (461 ± 149.5 g m−2) at the impact site. After sediment placement, in 2019, root biomass in the control site was significantly greater than the impact site.There was a significant two-factor site × time interaction term (p = 0.0042). At the impact site, transect mean shear strength after sediment placement (59.8 ± 5.4 kPa) was 64% greater than before sediment placement (36.6 ± 3.3 kPa). At the control site, there was no difference in mean shear strength between pre-sediment (43.2 ± 4.1 kPa) and post-sediment (37.1 ± 2.9 kPa) placement. Before sediment placement, there was no difference in shear strength between sites, but after sediment placement mean shear strength at the impact site was 61% greater than the control site at 10–30 cm depth. At 30–60 cm depth, there was no difference in shear strength between sites or time periods; transect means ranged from 53.7–68.2 kPa.For the 10–30 cm depth zone, there was a significant site × time interaction , with I. frutescens, P. australis, and brackish species in the upper ecotone and unvegetated areas interspersed on the platform  and over time . There was also a significant site × time interaction  such that vegetation changed significantly over time at the impact site, without concurrent changes at the control site. At the impact site, communities were significantly different between pre-sediment placement years and every post-sediment placement year, and between all pairs of post-sediment placement years except 2019–2020 , J. gerardii (15%), S. alterniflora (11%), and S. marina (9%) (S. marina and S. linearis) colonized bare ground after impact site sediment placement from 2018 to 2020  . Althoug to 2020 ; S. lineS. marina, Suaeda spp., Atriplex spp., and Salicornia spp.), total unvegetated, and bare ground  was trending strongly higher each year after impact site sediment placement, suggesting that cover of these species may not have plateaued 4 years after sediment placement  and biomass  every year after sediment placement at the impact site, but no change in stem density  or biomass  at the control site over time  at the control site than the impact site regardless of year , and P. australis biomass and stem density were both significantly higher at the control site than the impact site throughout the study , F. heteroclitus (16%) and striped killifish  (12%); all other species comprised less than 10% of the community, with 10 species making up <1% .Nekton communities in the two sites were typical of southern New England marshes, with low species richness and a small number of highly-abundant species. The impact site supported 21 species from 2015 to 2019, dominated by C. g up <1% . At the pseudo-F = 38.11, p = 0.001) and over time . There was also a significant site × time interaction  with contrasts indicating that impact marsh nekton communities were significantly different every year after sediment placement compared to before, but not different between any pair of years after sediment placement . These changes indicate an increased prevalence of sand-associated species in the impact marsh after sediment placement. The control site, in contrast, was consistently typified by marsh interior and brackish species such as F. heteroclitus, C. variegatus, P. pugio and rainwater killifish Lucania parva.Nekton communities were significantly different between sites  both increased. By year three post-sediment placement, densities of these species were either comparable or higher than initial. As with total density, however, significant site × time interactions were not detected for any individual species tested  further indicating that sediment placement had no apparent effect on nekton density  declined slightly (12%) the first year after sediment placement at the impact site, but rebounded in year two and exceeded initial levels by 63% in year three; the same pattern was found for total nekton population size, although the decline after sediment placement was more pronounced. Control marsh nekton density varied among years, but there was no clear trend over time ,B. These density .Changes in burrow density over time were nearly identical in both marshes, and there was no significant site × time interaction detected during our study, indicating that burrow density was apparently not affected by sediment placement .Agelaius phoeniceus) was the most dominant species (highest mean density) at both sites, and other dominant species were generally common to both marshes, including Song Sparrow (Melospiza melodia), Willet , Saltmarsh Sparrow (Ammospiza caudacuta), and Mourning Dove (Zenaida macroura).Fifty-one bird species were identified during this study , 38 at the impact site and 45 in the control . The numpseudo-F = 4.20, p = 0.001) but not between sites  and there was no significant site × time interaction . Communities were significantly different between every pair of years tested in both sites, suggesting that there were no effects from sediment placement on bird community structure and changes were likely rather due to broader-scale interannual variability  was approximately $600,000 (inclusive of adaptive management activities). Typically, these dredged sediments would have been used for beach nourishment, but in this restoration project they were instead used to increase elevation of the drowning Ninigret marsh. Assuming an ambient rate of elevation gain of 1.3 mm yrS. alterniflora, the dominant low marsh species, but the recovery trajectory evident from time-series and community analyses, which includes all species, is trending positive.Sediment placement successfully increased elevation capital for foundational high marsh plant species at the impact site, and thus increased salt marsh resilience. Unlike some restoration efforts targeting platform elevations that just meet optimal low marsh vegetation elevations and require only thin-layer sediment placement, project stakeholders decided to aim for the upper end of high marsh plant elevation growth ranges to build elevation capital and minimize maintenance costs of additional sediment applications. Consequently, recovery to optimal growth and biomass may take longer for some plant species, especially tall-form P. australis. The control site had higher P. australis cover in monitoring plots compared to the impact site throughout the study. However, P. australis elsewhere in the impact site was managed throughout the study by restoration specialists who were engaged in P. australis removal via hand-pulling and hydrological interventions . These management actions may have helped limit P. australis colonization into monitoring plots at the impact site; future monitoring after cessation of invasive species management will be needed to ultimately document P. australis response to adding sediment targeted at the upper end of optimal elevation ranges. More optimistically, these higher-elevation areas were rapidly colonized by ecotone species after sediment placement and should serve as future marsh migration corridors as sea-level rise continues.We caution that targeting high elevations to maximize elevation capital and promote optimal growth conditions for high marsh graminoids might inadvertently promote invasive species such as S. patens and promote seed-bearing, somewhat or fully succulent, annual colonizers such as Salicornia spp., forbs, and herbs. Subsequently, these early colonizers provide shade, reduce hypersaline conditions, and promote vegetative propagation by marsh grasses such as D. spicata and S. patens  in 2018–2020. We suspect that in future years, just as was reported for recovering bare spots due to wrack deposition  in areas where early colonizers are presently common.Under more natural conditions, bare areas on marsh platforms might result from wrack deposition , but in . patens . In our position , naturalSpartina species cover between the impact and control sites in 2019 or 2020, SIMPER and trend analyses suggested that while high marsh graminoid cover at the impact site exhibited a clear upward trajectory after sediment placement, cover at the control site remained stable. These community analyses also accounted for less-common plant species such as saltworts, forbs, and herbs, which were conspicuous colonizers of high-elevation bare areas at the impact site and demonstrated plant community succession as the marsh recovered.Placement of sediment on the impact site caused an increase in bare ground cover the first 2 years following placement, but by years three (2019) and four (2020), marsh plants had successfully re-vegetated bare areas to pre-placement and control levels. Similarly, the combined cover of the dominant two plant species at the impact site was not different from pre-sediment placement or control site cover by year three. Although we did not observe significant differences in S. alterniflora were significantly lower every year after sediment placement at the impact site compared to before, but were stable over time at the control site, suggesting this low-marsh dominant species was still recovering at the impact site 4 years after sediment placement. There were no apparent effects of sediment placement on stem density and biomass of other common species at the impact site. Future monitoring will determine if the elevation capital gains at the impact site will facilitate further increases in cover, stem density, and biomass of dominant grass species  and whether plant cover at the control site remains stable or begins to decline with expected accelerated SLR.Stem density and biomass of tall-form To our knowledge, ours was the first study to assess nekton and bird responses to sediment placement in the northeast U.S. For nekton, previous studies evaluating effects of marsh creation using dredged material in the Gulf of Mexico show that created marshes, regardless of age, provide valuable habitat for nekton . ResultsSimilarly, bird composition and abundance were unaffected by sediment placement, though this is unsurprising given the spatial and temporal scale of the project. It seems clear that highly-mobile birds were responding to factors beyond the scale of our study site given the matching temporal patterns observed between the impact and nearby control marsh. Previous studies demonstrate that birds readily use new marsh created from dredged material  and otheCharadrius melodus) in the impact site for the first time and detected twice as many Least Terns (Sternula antillarum) in the impact site in 2018 compared to any other year, though this difference was not significant. Beach nesting birds such as these are drawn to the bare sand deposited on the marsh surface, and we recommend that future projects consider the potential short-term benefits of large-scale sediment placement on these species. In addition, the Saltmarsh Sparrow (A. caudacuta), which breeds exclusively in northeast U.S. salt marshes, nests in high marsh vegetation, and is in a steep 9% annual decline , we detected Piping Plovers  with herbicide by a licensed applicator during the first year and then pulled by hand in subsequent years. These adaptive management activities helped limit the cover and biomass of this invasive species at the impact site, at least initially. Additional runnels that were dug through the salt marsh sill at the lower edge of the sediment placement area were effective at draining new shallow ponded areas and, apparently, reducing pore water salinity levels that were preventing plant re-colonization due to hypersaline conditions. The runnels also served as a conduit for fish passage.Adaptive management can be an essential component of successful restoration projects , but to D. spicata, likely due to its high salinity tolerance, while S. alterniflora survival was variable, with poor results at lower elevations where anoxic soils were present during the first growing season; S. patens and J. gerardii were generally difficult to establish). We also observed natural colonization of S. patens and J. gerardii via seeds from existing plants adjacent to the sediment placement area, suggesting that natural colonization may be important for large-scale revegetation of some species. Coupled with evidence that thick layers of added sediment can limit vegetative regrowth of buried plants  soon after sediment placement  may take a decade or more to reach equivalency with the control marsh and other reference salt marshes in southern New England . Some velacement , establical ones ; for futa priori goals, this project was a partial success after four years–the goal of increasing marsh resilience to SLR was quickly achieved, but it was not yet apparent if the goal of restoring high marsh habitat was fully met. Measured against objectives common across sediment placement projects (Measured against the two projects , howeverSupplement1


Balaena mysticetus) might be overwintering in the Canadian Beaufort Sea.Climate change is warming the Arctic faster than the rest of the planet. Shifts in whale migration timing have been linked to climate change in temperate and sub-Arctic regions, and evidence suggests Bering–Chukchi–Beaufort (BCB) bowhead whales (We used an 11-year timeseries (spanning 2009–2021) of BCB bowhead whale presence in the southern Chukchi Sea (inferred from passive acoustic monitoring) to explore relationships between migration timing and sea ice in the Chukchi and Bering Seas.p = 0.04, r2 = 0.40). Greater mean October–December Bering Sea ice area resulted in longer absences between whales migrating south in the fall and north in the spring . A stepwise shift after 2012–2013 shows some whales are remaining in southern Chukchi Sea rather than moving through the Bering Strait and into the northwestern Bering Sea for the winter. Spring northward migration into the southern Chukchi Sea was earlier in years with less mean January–March Chukchi Sea ice area and delayed in years with greater sea ice area .Fall southward migration into the Bering Strait was delayed in years with less mean October Chukchi Sea ice area and earlier in years with greater sea ice area (As sea ice continues to decline, northward spring-time migration could shift earlier or more bowhead whales may overwinter at summer feeding grounds. Changes to bowhead whale migration could increase the overlap with ships and impact Indigenous communities that rely on bowhead whales for nutritional and cultural subsistence.The online version contains supplementary material available at 10.1186/s40462-023-00374-5. Ursus maritimus), seals, walruses (Odobenus rosmarus), and whales rely on sea ice for a variety of needs, including access to prey and breeding habitat and for predator avoidance. Increased warming and the continued loss of sea ice will negatively impact some of these ice-obligate species [Balaena mysticetus) are the only baleen whale endemic to the Arctic and rely on phytoplankton blooms tied to annual sea ice melt that feed their zooplankton prey. However, the impacts of a changing Arctic on bowhead whales are less certain than for ice-obligate pinnipeds [Arctic amplification is changing the climate of the Arctic faster than the global average. Near-surface air temperatures have increased four times faster since 1979 . Arctic  species –6. Bowheinnipeds , 5, 7, winnipeds .The distribution and movement of Bering–Chukchi–Beaufort (BCB) bowhead whales in the western Arctic has been established from multiple lines of evidence, including aerial surveys, satellite tagging, passive acoustic monitoring (PAM), and Indigenous knowledge –13. AfteBowhead whale movement is strongly associated with the spatiotemporal availability of prey and distribution of sea ice –17. HoweChanges to bowhead whale migration could alter breeding phenology, increase their overlap with human use areas, especially as the Northern Sea Route, Northwest Passage and Transpolar Routes are used increasingly as Pacific-Atlantic shipping routes , 22, andBecause of the remoteness and extreme environmental conditions of the Arctic, studying bowhead whale migration over long time periods can be challenging. PAM is non-invasive, allows for long-term, year-round studies of free-ranging whales traveling through or under ice across large geographic ranges, and is a powerful tool for studies of animals that reliably produce sound. From late October to early May, encompassing fall/spring migration through the Bering Strait, bowhead whales produce call sequences repeated as song . Songs cHere we use a long-term PAM dataset spanning 2009–2021 to investigate BCB bowhead whale migration through the Bering Strait. Specifically, we examined: (1) the effect of sea ice metrics  on the timing of the southward migration in the fall from the southern Chukchi Sea through the Bering Strait (hereafter “southward passage”), movement from the Bering Strait into the northwestern Bering Sea in the winter, and northward migration in the spring through the Bering Strait into the southern Chukchi Sea (hereafter “northward passage”); and (2) the temporal trend  in the timing of the fall southward passage, movement from the Bering Strait to the northwestern Bering Sea in the winter, and northward passage in the spring. We hypothesize that sea ice in the Chukchi Sea is the driving force behind whales migrating through the Bering Strait in the fall and spring and that sea ice in the Bering Strait is the force behind bowhead whales moving out of the Bering Strait and into to the lower latitude Bering Sea/Bering Shelf for the winter.Passive acoustic data were collected by AURAL-M2  recording packages, which were deployed on moorings Fig.  in the s2) as opposed to sea ice extent (km) because even though they are similar, sea ice area is a more quantitative way of describing sea-ice coverage. Sea ice extent is calculated by the number of grid cells in a region with 15% or more sea ice, whereas sea ice area is the total region covered by ice. Because bowhead whales can feed along the sea ice edge and can break through sea ice up to 0.5 m thick with their heads [Daily north regional sea ice data for the Bering and Chukchi Seas were extracted from the sea ice index analysis spreadsheets, which are derived from Sea Ice Index V3 . We chosir heads , we wantMonthly LTSAs spanning October–May were manually visually assessed in Triton for the presence of bowhead whale song and non-song calls Fig. . For eacp ≥ 0.95). We used linear models to assess long-term trends in southward and northward passage dates with the base “stats” package in R  metrics spanning October–May, including monthly values, combinations of months, minimums, and maximums, etc., many of which were significant . To assp ≥ 0.99). We used linear models to assess the longitudinal trends in number of consecutive gap days with the base “stats” package in R  metrics spanning October–May, including monthly values, combinations of months, minimums, and maximums, etc., many of which were significant . To assBetween 2009 and 2021 roughly 22,235 h of bowhead song presence were documented as well as 4669 h of simple song and social/non-song call presence. Because we were interested in the acoustic presence of bowhead whales, if song was detected, we did not then search for calls in the same file. Bowhead whales were predominantly acoustically present from autumn throughout the spring months (November to mid-May) north of Bering Strait in the southern Chukchi Sea. The earliest bowhead whales were detected was 31 October (12 h of non-song presence in 2013) and the latest bowhead whales were detected was 15 May . Peak months for bowhead whale acoustic presence were December and January, each of which had a daily median of 24 call hours.p = 0.04, r2 = 0.40) to mean sea ice area in the Chukchi Sea in October . The latest southward passage (22 November) occurred during the 2018–2019 season, which was the migratory season with the third smallest mean sea ice area in the Chukchi Sea in October .The southward passage in the fall from the southern Chukchi Sea through the Bering Strait was positively linearly related  . The maximum number of consecutive absences in 2014–2015 (3 days) and in 2019–2020 (4 days) coincided with the second and fourth smallest mean sea ice areas in October-December in the Bering Sea .The maximum number of consecutive days that whales were acoustically absent between the southward and northward passage was positively linearly related to the mean sea ice area in October-December in the Bering Sea (85) Fig. . Migrato2 = 0.82) to mean sea ice area in the Chukchi Sea in January–March  and the smallest November sea ice extent on record. The latest northward passage (May 15) occurred during the 2011–2012 season, which coincided with the migratory season with the greatest mean sea ice area in the Chukchi Sea in January–March .The northward passage in the spring into the southern Chukchi Sea was positively linearly related . All but two southward passages happened in mid-November between JD 314 and JD 326, a 13-day window. Two early southward passages occurred in the 2012–2013 (JD 309) and 2013–2014 (JD 304) seasons.The onset of the southward passage from the southern Chukchi Sea and into the Bering Strait was assessed across 11 migratory seasons between 2009 and 2021, excluding the 2016–2017 season, for which there were no data. Southward passage Julian days (JD) ranged from JD 304 to JD 326 with a median of 318 (95% CI 307–324)  in the gaps from 2011 to 2021, exponential decay (pseudo r2 = 0.85) was a better fit, driven by the steep decline or stepwise shift in number of consecutive days with ≤ 3 h with calls after the 2011–2012 and 2012–2013 seasons  . Most northward passages happened early May, between JD 128 and JD 136, a 9-day window. Two outlier early northward passages occurred in 2013–2014 (JD 114) and 2017–2018 (JD 113).The timing of the northward passages through the Bering Strait and into the southern Chukchi Sea was assessed across 8 migratory seasons between 2009 and 2021, excluding the 2009–2010, 2010–2011, 2016–2017, and 2018–2019 seasons, where there were no or incomplete data. Northward passage JDs ranged from 113 to 136 with a median of 129 (95% CI 113–134) , which was the migratory season with the earliest end of northern migration (23 April). The linear model predicted a cessation of northward passage as early as 25 April in 2018, providing further evidence of earlier migration north through the Bering Strait and into the southern Chukchi Sea when sea ice is reduced. That same winter, acoustic evidence indicated that some bowhead whales overwintered in Amundsen Gulf and the eastern Beaufort Sea [While 2018–2019 was a migratory season in our study without good effort coverage , sea ice area January–March in the Chukchi Sea in 2018–2019 was close to that of 2017–2018  and humpback (Megaptera novaeangliae) whales arrived one month earlier in the Gulf of St. Lawrence over a 27-year period [Balaenoptera musculus) arrived 120 and 100 days earlier, respectively, in the Gulf of the Farallones over a 24-year period [Delphinapterus leucas) delayed departure from Beaufort Sea feeding areas in 2004–2012 compared to 1993–2002, coincident with delayed regional sea ice freeze-up in the Beaufort, Chukchi, and Bering Seas [Shifts in whale migration timing have been linked to climate change in temperate and sub-Arctic regions. Fin  passage from our study occurred within a ~ 2-week window across 11 migratory seasons. The median southward passage (14 November) was not different from averages from tagged bowhead whales in 2008 and 2009  . HoweverAlthough there was no long-term trend in annual southward or northward passage through the Bering Strait, there was a stepwise shift  in whale absence from the southern Chukchi Sea during the southward and northward passage across 9 migratory seasons. Chambault et al.  predicteOne of the biggest questions is how changes to migration patterns and timing will impact those who rely on bowhead whales for nutritional and cultural subsistence. In response to regional changes over the last 30 years, Yup’ik whalers in the northern Bering Sea have extended their harvest into late fall and winter months , 63. In Chionoecetes opilio) exists in the region [Continued sea ice decline may increase the overlap of whales with ships, exposure to ship noise, and increase overlap with fisheries and therefore increase entanglement risk. With decreased sea ice, the Northern Sea Route and Northwest Passage are becoming viable Pacific-Atlantic shipping routes where increased vessel traffic will pass through Bering Strait . Increase region . The mose region , 71. Shoe region .We used a dataset spanning 2009–2021 to examine the long-term trends in the fall southward migration from the southern Chukchi Sea through the Bering Strait, movement from the Bering Strait to the northwestern Bering Sea in the winter, and the spring northward migration through the Bering Strait into the southern Chukchi Sea. The major climate regime shift in 2017 may have driven the apparent step change in the migration patterns and timing of BCB bowhead whales. We hope to use the relationship we found with sea ice to predict future migration timing and compare migration timing at other sites in the western Arctic. Finally, we only looked at presence/absence in terms of number of hours per day with calling, but we do not yet know how many whales were present in the winter in the southern Chukchi Sea and northern Bering Strait. Future visual surveys or satellite images may help quantify the number of whales overwintering in the southern Chukchi Sea.Additional file 1. Supplementary tables with additional information, including migration dates and days absent for each season using different cutoffs; linear regressions between migration dates and days absent with other sea ice area metrics; and cross-correlations among sea ice area metrics.


Lepidotrigla microptera were hydrolyzed with four different proteolytic enzymes , and their distribution of molecular weights and ACE-inhibitory activity were tested. The alcalase hydrolysates showed the maximum ACE-inhibitory activity. A novel ACE-inhibitory peptide was isolated and purified from Lepidotrigla microptera protein hydrolysate (LMPH) using ultrafiltration, gel filtration chromatography, and preparative high performance liquid chromatography (prep-HPLC). The amino acid sequence of the purified peptide was identified as Phe-Leu-Thr-Ala-Gly-Leu-Leu-Asp (DLTAGLLE), and the IC50 value was 0.13 mg/mL. The ACE-inhibitory activity of DLTAGLLE was stable across a range of temperatures (<100 °C) and pH values (3.0–11.0) and retained after gastrointestinal digestion. DLTAGLLE was further identified as a noncompetitive inhibitor by Lineweaver–Burk plot. The molecular docking simulation showed that DLTAGLLE showed a high binding affinity with ACE sites by seven short hydrogen bonds. As the first reported antihypertensive peptide extracted from alcalase hydrolysate of Lepidotrigla microptera, DLTAGLLE has the potential to develop functional food or novel ACE-inhibitor drugs.In this study,  In recent years, long-standing stress, unhealthy dietary behavior, and fierce competition have compounded the problems of hypertension for many people. A report in 2005 projected that the number of adults with high blood pressure is expected to rise by about 60% to a total of 1.56 billion (1.54 billion to 1.58 billion) in 2025 . CentralIn order to treat hypertension effectively , many syLepidotrigla microptera is distributed in the Pacific Northwest and is cheap, high-yield, high in protein, and balanced in amino acids, making it a perfect source of nutrients. However, with its small size, extremely muddy flavor, and large quantity of fish bones, Lepidotrigla microptera is a low- market-value resource, and studies on bioactive polypeptide obtained from Lepidotrigla microptera protein (LMP) are scarce ) and the HA production rate (1/[v]) were used to analyze the inhibitory kinetics of peptide.The sample (0.2 mg/mL) was treated at various temperatures  for 1 h. After cooling the solution to indoor temperature (25 °C), the ACE inhibition activity was detected.The ACE-inhibitory peptide solution (0.2 mg/mL) was incubated at different pH levels  at 37 °C for 2 h, and the pH value was adjusted by adding HCl (1 mol/L) and NaOH (1 mol/L). Before the ACE inhibition rate was determined, the pH value was adjusted to 7.0.Simulated gastrointestinal digestion of ACE-inhibitory peptides was conducted following the method of Lai et al.  with sliThe three-dimensional crystal structure of ACE (PDB: 1O8A) was imported from the Protein Data Bank. Prior to docking analysis, the water molecules and inhibitor lisinopril were removed while the chloride atoms and cofactors zinc were reserved in the ACE model. The polar hydrogens were then added to the ACE crystal structure. Based on molecular simulations, the ACE was selected as the macromolecular receptor. The three-dimensional structure of the peptide was constructed using PyMol software, which was selected as small-molecule ligands. Molecular docking between the peptide molecule and ACE was carried out using a flexible docking tool via AutoDockTools-1.5.6 software. The docking runs were performed with a radius of 126 Å with coordinates x: 40.586, y: 37.374, and z: 43.446. The optimum docking position of the peptide in complex with ACE was selected according to the binding energy value and scores.50 (5.7 ± 0.15 mg/mL) was the lowest, followed by neutrase hydrolysates IC50 (6.5 ± 0.13 mg/mL) and flavourzyme hydrolysate IC50 (6.1 ± 0.11 mg/mL); the ACE inhibition rate of papain IC50 (6.8 ± 0.16 mg/mL) was the highest.The extent of protein degradation by protease was estimated by assessing the DH . The ord2 = 0.9758. Additionally, the distribution of the molecular weight of LMPH hydrolyzed by four proteolytic enzymes was presented in The ACE inhibition rate of the peptides was strongly linked to their molecular weight . Low-mol50 values of LMPH I, LMPH II, LMPH III, LMPH IV, and LMPH V were 0.77 ± 0.04, 1.23 ± 0.07, 1.8 ± 0.05, 4.31 ± 0.03, and 6.11 ± 0.06 mg/mL, respectively. The LMPH I fraction showed the highest inhibition ratio on ACE, which was significantly higher than that of LMPH II, LMPH III, LMPH IV, and LMPH V. Thus, LMPH I was collected for further purification.After the LMP was hydrolyzed with alcalase, ultrafiltration helped enrich the micromolecules and remove macromolecules as well as improve ACE-inhibitory activity. Through ultrafiltration, the hydrolysate was divided into five different fractions, namely LMPH I (MW < 1 kDa), LMPH II (MW 1–3 kDa), LMPH III (MW 3–5 kDa), LMPH IV (MW 5–10 kDa), and LMPH V (MW > 10 kDa); then it was lyophilized and compared in terms of the ACE-inhibitory activity of each proportion with different molecular weight ranges. The molecular weight of different fractions was inversely proportional to the ACE activity; that is to say, the ACE-inhibition rate decreased with the increase in molecular weight. The IC50 values of 0.38 ± 0.03 and 0.41 ± 0.05 mg/mL, respectively, and there was no significant difference between the two fractions  were subsequently eluted from the column according to molecular size a. Fractiractions b. Consid50 value of 0.28 mg/mL. Usually, separations that used prep -HPLC were based on hydrophilic properties; thus, hydrophilic peptides were eluted first and hydrophobic peptides were eluted later [The F4 from gel filtration chromatography was further separated by prep -HPLC into 19 fractions (named from F4-1 to F4-19) a, which ed later . F4-12 wed later ,37  and/or aromatic  at the first three C-terminal positions can dramatically increase the binding affinity between the peptide and ACE ,40,41. RTo further demonstrate the inhibitory kinetic mechanism of the novel ACE-inhibitory peptide, the ACE inhibition patterns of DLTAGLLE were estimated by Lineweaver–Burk plot analysis. The results are as shown in The ACE-inhibitory activity of DLTAGLLE peptide under different pH treatments is shown in The results in Molecular docking is an effective way to predict the interactions between the receptor and ligand by calculating the binding sites, the interaction energies, and other interaction information. ACE- and DLTAGLLE-inhibitory peptide interaction may be analyzed by molecular docking. Pina et al. reported that the active site of ACE involves 12 critical amino acid residues, namely Gln281, Ala354, His513, His383, Glu411, Glu162, His353, Glu384, His387, Lys511, Tyr523, and Tyr520 . In thisLepidotrigla microptera protein hydrolysates produced from papain, neutrase, flavourzyme, and alcalase showed substantial improvement in inhibitory activity ACE compared to Lepidotrigla microptera materials. Among the results, alcalase hydrolysates exhibited the highest inhibiting activity on ACE. A novel ACE-inhibitory peptide, DLTAGLLE, was purified from the Lepidotrigla microptera protein hydrolysates using ultrafiltration, G-15 gel chromatography, and prep-HPLC. DLTAGLLE was further proved to have noncompetitive inhibitory characteristics and revealed good stability to temperature, pH, and simulated gastrointestinal digestion. The molecular docking revealed that DLTAGLLE had a high binding force with ACE sites using short hydrogen bonds. The results of this study implied that DLTAGLLE has broad prospects in application to functional foods or therapeutic agents against hypertension. However, further research is needed to assess the safety of DLTAGLLE, including the absence of toxicity, allergenicity, and cytotoxicity; the antihypertensive mechanism of DLTAGLLE in vivo also needs further research.


Cephalosporins are the preferred antibiotics for prophylaxis against surgical site infections. Most studies give a rate of combined IgE and non-IgE penicillin allergy yet it is recommended that cephalosporins be avoided in patients having the former but can be used in those with the latter. Some studies use penicillin allergy while others penicillin family allergy rates. The primary goal of this study was to determine the rates of IgE and non-IgE allergy as well as cross reactions to both penicillin and the penicillin family. Secondary goals were to determine the surgical services giving preoperative cefazolin and the types of self reported reactions that patients’ had to penicillin prompting their allergy status.All patients undergoing elective and emergency surgery at a University Health Sciences Centre were retrospectively studied. The hospital electronic medical record was used for data collection.8.9% of our patients reported non-IgE reactions to penicillin with a cross reactivity rate of 0.9% with cefazolin. 4.0% of our patients reported IgE reactions to penicillin with a cross reactivity rate of 4.0% with cefazolin. 10.5% of our patients reported non-IgE reactions to the penicillin family with a cross reactivity rate of 0.8% with cefazolin. 4.3% of our patients reported IgE reactions to the penicillin family with a cross reactivity rate of 4.0% with cefazolin.Our rate of combined IgE and non-IgE reactions for both penicillin and penicillin family allergy was within the range reported in the literature. Our rate of cross reactivity between cefazolin and combined IgE and non-IgE allergy both to penicillin and the penicillin family were lower than reported in the old literature but within the range of the newer literature. We found a lower rate of allergic reaction to a cephalosporin than reported in the literature. We documented a wide range of IgE and non-IgE reactions. We also demonstrated that cefazolin is frequently the preferred antibiotics for prophylaxis against surgical site infections by many surgical services and that de-labelling patients with penicillin allergy is unnecessary. Cephalosporins are the preferred antibiotics for prophylaxis against surgical site infections in many procedures , 2. HoweMore recently, the cross reactions to cephalosporins in patients with a penicillin allergy has been reported to be lower than originally thought because of overestimation due to flawed methodologies and since levels of penicillin-specific IgE wane over time –30. ConsMost studies give a rate of combined IgE and non-IgE penicillin allergy. Some studies use penicillin allergy while others penicillin family  allergy rates. In addition, in studies to determine the cross reactivity cefazolin in only patients with self reported non-IgE penicillin allergy, we have previously found no patients to have a reaction when it is given for prophylaxis against surgical site infections in hip and knee replacement surgery, and spine surgery , 37. As The primary goal of this study was to determine the rates of IgE and non-IgE allergy as well as cross reactions to both penicillin and the penicillin family and to increase the power of our previous studies. Secondary goals were to determine the surgical services giving preoperative cefazolin and the types of self reported reactions that patients’ had to penicillin prompting their allergy status.All patients undergoing elective and emergency surgery at the inpatient and ambulatory care hospitals at a University Health Sciences Centre from July 2015 to December 2015 were retrospectively studied The electronic medical record was used to review the presurgical screening assessment, preoperative history and physical, surgery booking form, O.R. report, intraoperative Anaesthesia record, and recovery room record. From these documents, data was collected concerning preoperative patient reported penicillin or penicillin family allergic reactions, surgical service involved, preoperative antibiotics, and intraoperative or immediate postoperative allergic reactions. IgE and IgE allergy was assumed based on the symptoms reported by the patients. Ethics and consent clearance was obtained from the University Health Sciences & Affiliated Teaching hospitals Research Ethics Board (TRAQ#:6016119).https://www.graphpad.com/quickcalcs/contingency1.cfm) to assess statistical significance. When any value in the 2 × 2 table had a frequency of 5 or less, the p-value was generated by the Fisher’s Exact test, otherwise the p-value from the uncorrected Chi-square was utilized. P < 0.05 was considered to be significant.The data was entered onto a Microsoft Excel version12.3.3  spreadsheet and tabulated using SAS version 9.4 . Our rates were compared to the published high and low values using an on-line calculator (486 of 5433 patients (8.9%) reported non-IgE reactions to penicillin Fig. . 215 of 217 of 5433 patients (4.0%) reported IgE reactions to penicillin  cross reactivity between reported IgE allergy to penicillin and cefazolin and a 2/215 (0.9%) cross reactivity between reported non-IgE allergy to penicillin and cefazolin. Therefore, there was a 4/265 (1.5%) cross reactivity between reported allergy to penicillin and cefazolin in this study.570 of 5433 patients (10.5%) reported non-IgE reactions to the penicillin family Fig. . 255 of 232 of 5433 patients (4.3%) reported IgE reactions to the penicillin family  cross reactivity between reported IgE reaction to the penicillin family and cefazolin and a 2/255 (0.8%) cross reactivity between reported non-IgE allergy to the penicillin family and cefazolin. Therefore, there was a 4/305 (1.3%) cross reactivity between reported allergy to the penicillin family and cefazolin in this study.There were a total of 17 out of 5433 patients that had reactions in this study. 12 of these were patients that had an allergic reaction to a cephalosporin  and needed Benedryl® 9.5 h later with no reason given). Four of these were in patients not reporting allergic to penicillin and that did not receive cefazolin  X1 3.5 h postoperatively no reason given). One of these was in a patient reporting a rash to ceftazidime and given Vancomycin but stopped because of hypotension and required phenyepherine.203 of 212 Cardiac Surgery cases (95.8%), 1156 of 1334 Orthopaedic cases (86.7%), 317 of 372 Urology cases (85.2%), 181 of 214 Neurosurgery cases (84.6%), 101 of 131 Vascular Surgery cases (77.1%), and 40 of 54 Thoracic Surgery cases (74.1%) were given cefazolin , Orthopaedics (86.7%), Urology (85.2%), Neurosurgery (84.6%), Vascular Surgery (77.1%), and Thoracic Surgery (74.1%) had the highest percentage per case use of cefazolin Fig. .Most studies give a rate of combined IgE and non-IgE penicillin allergy. However, recommendations for use of cephalosporins depends on the type of allergy to penicillin. Specifically, Pichichero recommends that if a patient experienced a reaction to a penicillin or cephalosporin that was not IgE mediated and was not serious, it is safe to administer repeated courses of that antibiotic and related antibiotics. Only IgE mediated reactions are likely to become more severe with time and to result in anaphylaxis . This reSome studies use penicillin allergy while others penicillin family allergy rates. We found a 12.9% (8.9% IgE and 4.0% non-IgE) reported rate of penicillin allergy versus 14.8% (10.5% IgE and 4.3% non-IgE) for the penicillin family. Both are within the range reported in the literature where there is a high of 15.6% and a low of 5.0% (Table We found a 1.5% (4.0% IgE and 0.9% non-IgE) cross reactivity between reported allergy to penicillin and cefazolin and 1.3% (4.0% and 0.8%) cross reactivity between penicillin family and cefazolin. Both are lower than the old literature high of 18.2% and low of 4.1%. Both are within the newer literature high of 2.4% and low of 0.2%  which could have safely been given cefazolin , 26. TheThis study was limited by its retrospective nature, which may have affected the accuracy of data recorded. Reactions could have been missed or alternatively, clinical signs and symptoms of an allergic reaction could have been inappropriately attributed to the administration of antibiotics when in fact they were due to some other medication or condition. Examples of this latter possibility is that of our 17 patients with reactions, 4 got no antibiotics yet 1 had a transient rash after propofol and before rocuronium; 1was given Benadryl® X1, 5 h postoperatively with no reason given; 1 was given Decadron® × 1, 3.5 h postop with no reason given; 1 had 3 + pruritis despite Benadryl® noted 5.5 h after general anaesthesia.A further limitation is that we looked for reactions only up to the time that the patients were recovered from surgery, typically < 24 h and did not address delayed reactions. Although we recorded non-IgE reactions Tables , 2, IgE We met our primary goals of separating the rates of IgE and non-IgE allergy and cross reactions to penicillin and the penicillin family. We found that the combined rates of combined IgE and non-IgE reactions for both penicillin and penicillin family allergy was within the range reported in the literature. Our rate of cross reactivity between cefazolin and combined IgE and non-IgE allergy both to penicillin and the penicillin family were lower than reported in the old literature but within the range of the newer literature. We demonstrated a lower rate of allergic reaction to a cephalosporin than reported in the literature. We also determine that cefazolin is frequently the preferred antibiotics for prophylaxis against surgical site infections by many surgical services and that de-labelling is not necessary.


To explore the entry point, orientation, and fixation range of retrograde acetabular posterior column screw.The computed tomography data of 100 normal adult pelvises  were collected and pelvis three-dimensional (3D) reconstruction was performed by using Mimics software and the 3D model was imported into Geomagic Studio software. The perspective of acetabular posterior column was carried out orienting from ischial tuberosity to iliac fossa in the Mimics software. Virtual screw was inserted perpendicular to the transverse section of acetabular posterior column corridor, and the maximum screw diameter, entry point, orientation, exit point were measured. The screw fixation range, the easy-to-penetrate sites, and intraoperative optimal fluoroscopic views were assessed.The acetabular posterior column corridor showed a triangular-prism shape. The virtual screw entry point was located at the midline between the medial and lateral edges of the ischial tuberosity. The distance between the entry point and the distal ischial tuberosity was around 13 mm. The distances between the exit point and the true pelvis rim, and ipsilateral anterior sacroiliac joint line were (19.33 ± 2.60) mm and (23.65 ± 2.42) mm in males, respectively. As for females, those two data were (17.63 ± 2.00) mm and (24.94 ± 2.39) mm, respectively. The maximum diameters of screws were (17.21 ± 1.41) mm in males and (15.54 ± 1.51) mm in females. The angle between the retrograde posterior column screw and the sagittal plane was lateral inclination (10.52 ± 3.04)° in males, and that was lateral inclination (7.72 ± 2.99)° in females. Correspondingly, the angle between the screw and the coronal plane was anterior inclination (15.00 ± 4.92)° in males, and that was anterior inclination (12.94 ± 4.72)° in females. Retrograde acetabular posterior column screw through ischial tuberosity can fix the acetabular posterior column fractures which were not 4 cm above the femoral head center. The easy-to-penetrate sites were located at the transition between the posterior acetabular wall and the ischium, the middle of the acetabulum, and 1 cm below the greater sciatic notch, respectively. The iliac oblique 10°, iliac oblique 60°, and obturator oblique 60° views were the intraoperative optimal fluoroscopic views to assess whether the screw was safely inserted.Retrograde acetabular posterior column screw entry point is located at the midline between the medial and lateral edges of the ischial tuberosity, which is 1.3 cm far from the distal ischial tuberosity. The screw direction is about 10° lateral inclination and 15° anterior inclination, which can fix the acetabular posterior column fractures which were not 4 cm above the femoral head center. Open reduction and internal fixation is the first choice for the treatment of displaced acetabular fractures; however, the operation is difficult and traumatic , 2. ReceTherefore, the present study using the Mimics software and Geomagic Studio software simulated the placement of percutaneous retrograde acetabular posterior column screw, and explored the morphological characteristics of acetabular posterior column corridor, the entry point, orientation, and easy-to-penetrate sites, which aimed to provide imaging anatomical evidence for retrograde lag screw in fixation of acetabular posterior column fractures.The CT data of pelvis were collected from the department of radiology in the First Affiliated Hospital of Chongqing Medical University. From October 2017 to October 2018, 100 patients  enrolled in the study, aged from 18 to 86 years old (mean age was 48.96 ± 18.48). Participators with tumor, fracture or infection were excluded. The data were reserved by digital imaging communication in medicine (DICOM) format. The DICOM format data were imported into Mimics 17.0 software  and 3D reconstruction of the pelvis was performed. The reconstructed 3D model of the pelvis was imported into the Geomagic Studio 2015 software  in stereolithography (STL) format. The pelvis model was processed according to the method proposed by Feng et al. [The perspective of acetabular posterior column was carried out orienting from ischial tuberosity to iliac fossa in the Mimics software. The acetabular posterior column corridor showed a triangular-prism shape, which was encircled by the posterior acetabular wall, the quadrilateral plate, and acetabular dome. Whereafter, the virtual screw was inserted perpendicular to the cross section of triangular prism. The maximum screw diameter was achieved by gradually increasing the screw diameter when the screw was tangent to the three sides of the cross section at the same time. We reduced the screw diameter to 0.5 mm, then the screw intersected the ischial tuberosity at Point P (entry point) and the medial cortex of the iliac fossa at Point O (exit point), respectively. The distance between Point P and O was the length of the acetabular posterior column corridor. The location relationship between Point P with the lateral and medial edge of ischial tuberosity was recorded. The distance between Point P and the distal ischial tuberosity was measured, which was recorded as PL. Passing Point O, the perpendicular line of true pelvic rim was drawn, and we obtained the intersection Point F. Passing Point F, the extension line of the true pelvic rim was drawn, and Point E was obtained which was the intersection of true pelvic rim extension line and the ipsilateral anterior sacroiliac joint line. The line segment OF was the distance between exit point and the true pelvic rim, and OE was the distance between exit point and ipsilateral anterior sacroiliac joint line Fig. .Fig. 1PaProject function of the Mimics software was used to re-cut the acetabulum. The re-cut layers from Point P to Point O were perpendicular to the longitudinal axis of the screw with an interval of 5 mm.The screw diameter was increased to 7.3 mm, then passing the border line of the screw in the sectional view, and the perpendicular lines of quadrilateral plate, posterior acetabular wall, and acetabular dome, respectively, were drawn. The distance between screw and quadrilateral plate, posterior acetabular wall, and acetabular dome were marked as H1, H2 and H3, respectively. We defined the high acetabular posterior column fracture as the fracture line was above the center of femoral head. Correspondingly, the fracture line of low acetabular posterior column fracture was below the center of femoral head. We measured the distance between the plane of femoral head center and 16 mm below the exit point, which was marked as DK, hence we could obtain the fixation range of screw (The screw was 16 mm threaded)  were just tangent to the cortex of the acetabular posterior column corridor, and the maximum screw angles with coronal and sagittal planes were obtained Fig. .Fig. 4Mep value smaller than 0.05.All analyses were performed using SPSS software 19.0 . The differences of measurement data between male and female were compared with independent sample t test. The threshold for statistical significance was set at The virtual screw entry point located at the midline is the ischial tuberosity. The distance between the entry point and the distal ischial tuberosity was (12.99 ± 1.99) mm in males. As for females, that was (13.26 ± 2.58) mm. According to statistical analysis, there was no significant difference between male and female. The distances between the exit point and the true pelvis rim, and ipsilateral anterior sacroiliac joint line were (19.33 ± 2.60) mm and (23.65 ± 2.42) mm in males, respectively. As for females, those were (17.63 ± 2.00) mm and (24.94 ± 2.39) mm, respectively. These differences had statistical significances between males and females. The corridor length and maximum screw diameter were significantly greater in males  . The α, β, and γ were, respectively (10.95 ± 2.29)°, (118.62 ± 4.43)°, and (63.62 ± 2.63)°in males, which were the angles between the three sides of the triangular-prism and the sagittal plane of pelvis. As for females, those were (11.73 ± 2.25)°, (119.39 ± 3.73)°, and (64.02 ± 2.69)°. The differences in these angles did not reach statistical significance between male and female. The above data are shown in Tables Morphological characteristics of acetabular posterior column corridor were variable. There were 5–7 re-cut layers in the ischial tuberosity, and the shape of the cross section was approximate to triangle. From the transition of the ischial tuberosity to the inferior of acetabulum, there were just 2 layers. In this part, the cross section presented an oval shape. From the inferior of acetabulum to the greater sciatic notch, 10–12 layers were obtained, and the cross section shape converted to triangle again. There were 3–5 layers from the greater sciatic notch to exit point, and an approximate parallelogram shape of cross section was demonstrated Fig. . AccordiWe retrogradely inserted a 7.3 mm virtual screw through the ischial tuberosity. The angle between the retrograde posterior column screw and the sagittal plane was lateral inclination (10.52 ± 3.04)° in males, and (7.72 ± 2.99)° in females. Correspondingly, the angle between the screw and the coronal plane was anterior inclination (15.00 ± 4.92)° in males, and (12.94 ± 4.72)° in females. According to statistical analysis, there were significant differences between male and female. The combination of the two mean critical angles in the same plane presented the safety range of the screw. The safety range of lateral inclination was about 8°, and of anterior inclination was about 11° Tables ,7.Table In our study, the length of acetabular posterior column corridor and the maximum screw diameter in males were greater than those in females, which might be caused by broader pelvis in males. The acetabular posterior column corridor demonstrated an irregular shape on the perspective, which had a triangular-prism shape from inferior of acetabulum to the greater sciatic notch. The diameters of acetabular posterior column corridor were 17.21 ± 1.41 mm and 15.54 ± 1.51 mm in males and females, respectively, which is sufficient to accommodate a virtual screw with a diameter of 7.3 mm. Furthermore, three 7.3 mm screws could be inserted in this corridor in males and three 6.5 mm screws were feasible for females in theory , partial thread screws (16 mm threaded), and full thread screws. When fixing acetabular posterior column fractures, the threaded head of the screw should completely traverse the fracture in order to achieve stable fixation; therefore the selection of screws may affect the fixation range. Biomechanical studies revealed that long threaded screws and fully threaded screws showed significantly higher stiffness and less failure compared to conventional partial threaded screws , 16. In