Death due to sickle cell crisis: a case report.

Sickle cell disease (SCD) is the most common hereditary hemoglobinopathy worldwide. It results in characteristic acute and chronic findings on postmortem computed tomography (PMCT), macroscopic and microscopic examinations. While the diagnostic imaging and macroscopic features are not specific for SCD on their own, when coupled with microscopic features such as sickled erythrocytes and evidence of chronic venous congestion (i.e., Gamna-Gandy bodies), these clues can help alert forensic pathologists to the presence of SCD. Despite the prevalence of the disease and the constellation of findings alluded to above, SCD is not often explored in forensic pathology literature. This case demonstrates classic acute and chronic features of SCD on PMCT, macroscopic and microscopic examinations. It explores the pathophysiology leading to sudden and unexpected death in a person with SCD and possible pitfalls in attribution of cause of death.

Peak grain forecasts for the US High Plains amid withering waters.

Irrigated agriculture contributes 40% of total global food production. In the US High Plains, which produces more than 50 million tons per year of grain, as much as 90% of irrigation originates from groundwater resources, including the Ogallala aquifer. In parts of the High Plains, groundwater resources are being depleted so rapidly that they are considered nonrenewable, compromising food security. When groundwater becomes scarce, groundwater withdrawals peak, causing a subsequent peak in crop production. Previous descriptions of finite natural resource depletion have utilized the Hubbert curve. By coupling the dynamics of groundwater pumping, recharge, and crop production, Hubbert-like curves emerge, responding to the linked variations in groundwater pumping and grain production. On a state level, this approach predicted when groundwater withdrawal and grain production peaked and the lag between them. The lags increased with the adoption of efficient irrigation practices and higher recharge rates. Results indicate that, in Texas, withdrawals peaked in 1966, followed by a peak in grain production 9 y later. After better irrigation technologies were adopted, the lag increased to 15 y from 1997 to 2012. In Kansas, where these technologies were employed concurrently with the rise of irrigated grain production, this lag was predicted to be 24 y starting in 1994. In Nebraska, grain production is projected to continue rising through 2050 because of high recharge rates. While Texas and Nebraska had equal irrigated output in 1975, by 2050, it is projected that Nebraska will have almost 10 times the groundwater-based production of Texas.

Validation of the Gait Outcomes Assessment List questionnaire and caregiver priorities for individuals with cerebral palsy.

AIM: To expand upon previous validation of the Gait Outcomes Assessment List (GOAL) questionnaire in individuals with cerebral palsy (CP), to rank items by importance, and to summarize written-in (free text) goals. METHOD: For this cross-sectional study, the parent-version 5.0 of the GOAL was completed by 310 consecutive caregivers of 310 individuals aged 3 to 25 years with CP (189 males, 121 females; mean [SD] age: 10y [4y 2mo]; Gross Motor Function Classification System [GMFCS] levels I-IV) concurrent with a gait analysis. Distribution properties and validity were quantified using questionnaires, kinematics, and oxygen consumption. Items classified as at least 'difficult' to perform and 'very important' to improve were considered caregiver priorities and rank ordered. Free text goals were categorized. Results were summarized for everyone and by GMFCS level. RESULTS: Most scores were normally distributed. Validity was acceptable, with concurrent greater than construct validity. Among all 310 caregivers, fatigue was the highest priority, followed by gait pattern and appearance items. The rank of priorities varied by GMFCS level. Common free text goals included toileting independently as well as improved fine motor and ball sport skills. INTERPRETATION: The GOAL is a valid tool that can help prioritize goals across GMFCS levels I to IV. Identifying the top goals may improve shared decision-making and prioritize research for this sample.

Knee pain and crouch gait in individuals with cerebral palsy: what impact does crouch-related surgery have?

AIM: To investigate the effect of crouch-related surgery on knee pain in individuals with cerebral palsy. METHOD: We retrospectively identified individuals with two three-dimensional gait analyses at baseline and follow-up visits. All individuals walked in crouch gait at baseline. Visits were 9 months to 42 months apart. Baseline knee pain, age, crouch-related surgery (yes/no), and minimum knee flexion at follow-up were entered into a logistic regression to predict follow-up knee pain. RESULTS: Thirty-two individuals (21 males, 11 females; mean [SD] age 12y 10mo [2y 5mo]; 8y 1mo-18y 7mo) received crouch-related surgery, while 19 were managed non-surgically. At baseline, knee pain prevalence was 38% in the surgical group and 21% in the non-surgical group. At follow-up, 34% of the surgical group and 16% of the non-surgical group had knee pain (odds ratio: 2.809, p=0.285). INTERPRETATION: Crouch-related surgery does not appear to decrease knee pain prevalence compared to a comparison group, based on this preliminary study. Further investigation of the roles of these procedures is indicated with regards to this patient-reported outcome. What this paper adds Approximately 38% of individuals undergoing crouch-related surgery had knee pain. Approximately 42% of individuals with baseline knee pain who had surgery still had knee pain 1 year postoperatively. Approximately 50% of those with baseline knee pain managed non-surgically still had knee pain 1 year later. Crouch-related surgery tended not to decrease knee pain prevalence 1 year postoperatively.

Dolor de rodilla y marcha en cuclillas en personas con parálisis cerebral: ¿qué impacto tiene la cirugía indicadas para esta deformidad? OBJETIVO: Investigar el efecto de la cirugía relacionada con la marcha en cuclillas con el dolor de rodilla en personas con parálisis cerebral. MÉTODO: Identificamos retrospectivamente a los individuos con dos análisis tridimensionales de la marcha al inicio y en las visitas de seguimiento. Todos los individuos caminaron en cuclillas al inicio del estudio. Las visitas fueron de 9 a 42 meses de diferencia. El dolor al inicio, edad, la cirugía relacionada con este tipo de marcha (sí / no) y la flexión mínima de la rodilla en el seguimiento, se ingresaron en una regresión logística para predecir el dolor de rodilla de seguimiento. RESULTADOS: Treinta y dos individuos (21 varones, 11 mujeres; media [DE] edad 12 años 10 meses [2 años 5 meses]; 8 años 1 mes - 18 años 7 meses) recibieron cirugía para corregir esta alteración, mientras que 19 fueron manejados sin cirugía. Al inicio del estudio, la prevalencia del dolor de rodilla fue del 38% en el grupo quirúrgico y del 21 por ciento en el grupo no quirúrgico. En el seguimiento, el 34% del grupo quirúrgico y el 16% del grupo no quirúrgico tenían dolor de rodilla (odds ratio: 2,809, p = 0,285). INTERPRETACIÓN: Según este estudio preliminar, la cirugía relacionada para la marcha en cuclillas, no parece disminuir la prevalencia del dolor de rodilla en comparación con un grupo de comparación. Se sugiere una investigación adicional de las funciones de estos procedimientos con respecto a los resultados informados por pacientes.

Dor no joelho e marcha agachada em indivíduos com paralisia cerebral: qual o impacto da cirurgia relacionada à marcha agachada? OBJETIVO: Investigar o efeito de cirurgia relacionada à marcha agachada na dor no joelho de indivíduos com paralisia cerebral. MÉTODO: Identificamos retrospectivamente indivíduos com duas análises tridimensionais da marcha em visitas de linha de base e acompanhamento. Todos os indivíduos apresentavam marcha agachada na linha de base. As visitas tiveram de 9 a 42 meses de distância. A dor no joelho, idade, cirurgia relacionada à marcha agachada (sim/não) na linha de base, e flexão mínima do joelho no acompanhamento foram inseridas em uma regressão logístia para predizer a dor no joelho no acompanhamento. RESULTADOS: Trinta e dois indivíduos (21 do sexo masculino, 11 do sexo feminino; média [DP] de idade 12a 10m [2a 5m]; 8a 1m-18a 7m) receberam cirurgia relacionada à marcha agachada, enquanto 19 tiveram manejo não-cirúrgico. Na linha de base, a prevalência de dor no joelho era 38 por cento no grupo cirúrgico, e 21 por cento no grupo não-cirúrgico. No acompanhamento, 34 por cento do grupo cirúrgico e 16 por cento do grupo não cirúrgico tiveram dor no joelho (taxa de risco: 2,809, p=0,285). INTERPRETAÇÃO: A cirurgia relacionada à marcha agachada não parece diminuir a prevalência de dor no joelho em relação a um grupo de comparação, com base neste estudo preliminar. Mais investigações sobre o papel destes procedimentos são indicadas, com relação a este desfecho relatado pelos pacientes.

Nitrogen futures in the shared socioeconomic pathways 4.

Humanity's transformation of the nitrogen cycle has major consequences for ecosystems, climate and human health, making it one of the key environmental issues of our time. Understanding how trends could evolve over the course of the 21st century is crucial for scientists and decision-makers from local to global scales. Scenario analysis is the primary tool for doing so, and has been applied across all major environmental issues, including nitrogen pollution. However, to date most scenario efforts addressing nitrogen flows have either taken a narrow approach, focusing on a singular impact or sector, or have not been integrated within a broader scenario framework - a missed opportunity given the multiple environmental and socio-economic impacts that nitrogen pollution exacerbates. Capitalizing on our expanding knowledge of nitrogen flows, this study introduces a framework for new nitrogen-focused narratives based on the widely used Shared Socioeconomic Pathways that include all the major nitrogen-polluting sectors (agriculture, industry, transport and wastewater). These new narratives are the first to integrate the influence of climate and other environmental pollution control policies, while also incorporating explicit nitrogen-control measures. The next step is for them to be used as model inputs to evaluate the impact of different nitrogen production, consumption and loss trajectories, and thus advance understanding of how to address environmental impacts while simultaneously meeting key development goals. This effort is an important step in assessing how humanity can return to the planetary boundary of this essential element over the coming century.

Association of Knee Pain and Crouch Gait in Individuals With Cerebral Palsy.

BACKGROUND: Crouch gait (ie, excessive knee flexion) is commonly seen in patients with cerebral palsy (CP) and has been inconsistently linked with knee pain. The definitive cause of knee pain is unknown, but may result from increased joint forces due to crouch gait kinematics. Our purpose was to determine whether knee pain is positively associated with knee flexion in gait among a large sample of ambulatory individuals with CP. We hypothesized that knee pain prevalence would increase as knee flexion increased. METHODS: In this retrospective study, pain questionnaire and 3-dimensional gait analysis data from 2015 to 2018 were extracted from the medical records of individuals with CP who had a clinical gait analysis. The pain questionnaire asked caregivers/patients to indicate the location of pain and when it occurs. A multivariate logistic regression was performed with minimum knee flexion in stance, patella alta, age, and sex as predictors of knee pain. RESULTS: Among the 729 participants included in the analysis, 147 reported knee pain (20.1%). The odds of knee pain were not associated with minimum knee flexion in stance or sex. However, the odds of knee pain increased 73.2% when patella alta was present (P=0.008) and tended to increase 2.2% as age increased (P=0.059). CONCLUSIONS: The data suggest that there is not a meaningful association between crouch gait and knee pain. Having patella alta was associated with pain. Further studies that use validated pain questionnaires are needed to understand the multifactorial etiology of knee pain within ambulatory individuals with CP. LEVEL OF EVIDENCE: Level III-case-control study.

How Hydrologic Connectivity Regulates Water Quality in River Corridors.

Downstream flow in rivers is repeatedly delayed by hydrologic exchange with off-channel storage zones where biogeochemical processing occurs. We present a dimensionless metric that quantifies river connectivity as the balance between downstream flow and the exchange of water with the bed, banks, and floodplains. The degree of connectivity directly influences downstream water quality - too little connectivity limits the amount of river water exchanged and leads to biogeochemically inactive water storage, while too much connectivity limits the contact time with sediments for reactions to proceed. Using a metric of reaction significance based on river connectivity, we provide evidence that intermediate levels of connectivity, rather than the highest or lowest levels, are the most efficient in removing nitrogen from Northeastern United States' rivers. Intermediate connectivity balances the frequency, residence time, and contact volume with reactive sediments, which can maximize the reactive processing of dissolved contaminants and the protection of downstream water quality. Our simulations suggest denitrification dominantly occurs in riverbed hyporheic zones of streams and small rivers, whereas vertical turbulent mixing in contact with sediments dominates in mid-size to large rivers. The metrics of connectivity and reaction significance presented here can facilitate scientifically based prioritizations of river management strategies to protect the values and functions of river corridors.

Proximal versus distal femoral derotation osteotomy in bilateral cerebral palsy.

AIM: Femoral derotation osteotomy (FDO) can be conducted either proximally or distally to correct internal rotation gait (IRG) and increased anteversion in children with cerebral palsy (CP). Previous studies with limited numbers of participants have presented comparable short-term static and kinematic outcomes for both techniques. The objective of this retrospective multicentre study was to verify this thesis with a larger number of patients. METHOD: In total, 119 children with CP and IRG were included after matching the groups on preoperative mean stance hip rotation: 67 intertrochanteric (proximal group) FDO (average age at surgery 9y [SD 3y]); 52 supracondylar (distal group) FDO (average age at surgery 12y [SD 3y]). One random limb of each child was analyzed. Both transverse plane kinematic gait data and torsional parameters of clinical examination were assessed preoperatively and postoperatively. RESULTS: On average, both groups' mean hip rotation and midpoint of hip rotation improved postoperatively, and groups did not differ preoperatively or postoperatively for these variables (p>0.05). INTERPRETATION: The osteotomy location does not influence short-term gait kinematics nor static measurements. Therefore, the choice of performing proximal or distal FDO in children with CP for treatment of IRG and increased anteversion should be motivated by considerations other than these outcome parameters. WHAT THIS PAPER ADDS: Femoral derotation osteotomy (FDO) location does not influence mean stance hip rotation in cerebral palsy (CP). FDO location does not influence mid-point hip rotation in CP. FDO location should be motivated by concomitant procedures performed.

Lower extremity joint loads in habitual rearfoot and mid/forefoot strike runners with normal and shortened stride lengths.

Our purpose was to compare joint loads between habitual rearfoot (hRF) and habitual mid/forefoot strikers (hFF), rearfoot (RFS) and mid/forefoot strike (FFS) patterns, and shorter stride lengths (SLs). Thirty-eight hRF and hFF ran at their normal SL, 5% and 10% shorter, as well as with the opposite foot strike. Three-dimensional ankle, knee, patellofemoral (PF) and hip contact forces were calculated. Nearly all contact forces decreased with a shorter SL (1.2-14.9% relative to preferred SL). In general, hRF had higher PF (hRF-RFS: 10.8 ± 1.4, hFF-FFS: 9.9 ± 2.0 BWs) and hip loads (axial hRF-RFS: -9.9 ± 0.9, hFF-FFS: -9.6 ± 1.0 BWs) than hFF. Many loads were similar between foot strike styles for the two groups, including axial and lateral hip, PF, posterior knee and shear ankle contact forces. Lateral knee and posterior hip contact forces were greater for RFS, and axial ankle and knee contact forces were greater for FFS. The tibia may be under greater loading with a FFS because of these greater axial forces. Summarising, a particular foot strike style does not universally decrease joint contact forces. However, shortening one's SL 10% decreased nearly all lower extremity contact forces, so it may hold potential to decrease overuse injuries associated with excessive joint loads.

Changes in hip abductor moment 3 or more years after femoral derotation osteotomy among individuals with cerebral palsy.

AIM: To examine the effect of femoral derotation osteotomy (FDO) on dimensionless hip abductor moment during gait in children with cerebral palsy. METHODS: We retrospectively analyzed data from independent ambulators within our database. Postoperative visits 1 year (short-term) and at least 3 years (mid-term) were analyzed. We estimated the coronal plane hip abductor moment arm based on musculoskeletal modeling that accounted for anteversion and hip rotation. RESULTS: There were 140 individuals with a short-term analysis (77 males, 63 females; age at surgery 9y 11mo [range 4y 5mo-17y 5mo]) and 29 with mid-term analysis (15 males, 14 females; age at surgery 8y 7mo [range 4y 5mo-13y 1mo]). At short-term, anteversion and internal hip rotation decreased 35° and 13° respectively, which increased median (IQR) moment arms from 20 (23) per cent below normal to 2 (12) per cent above normal. Dimensionless mean hip abductor moment remained unchanged at short-term. Mid-term anteversion did not change but hip rotation increased 8° and hip abductor moment increased to 0.040 (0.029). There was no change in pelvic and trunk obliquity, although hip abductor strength increased and walking velocity decreased at mid-term. INTERPRETATION: The unexpected lack of improvement in hip abductor moment from pre- to short-term may be caused by gait compensations that unload the hip. The increase in hip abductor moment beyond 3 years postoperatively underscores the benefits of an FDO into adolescence for independent ambulating individuals with cerebral palsy.

Parsimonious Model for Simulating Total Mercury and Methylmercury in Boreal Streams Based on Riparian Flow Paths and Seasonality.

The complexity of mercury (Hg) biogeochemistry has made it difficult to model surface water concentrations of both total Hg (THg) and especially methylmercury (MeHg), the species of Hg having the highest potential for bioaccumulation. To simulate THg and MeHg variation in low-order streams, we have adapted a conceptual modeling framework where a continuum of lateral flows through riparian soils determines streamflow concentrations. The model was applied to seven forest catchments located in two boreal regions in Sweden spanning a range of climatic, soil, and forest management conditions. Discharge, and simulated riparian soil water concentrations profiles, represented by two calibrated parameters, were able to explain much of the variability of THg and MeHg concentrations in the streams issuing from the catchments (Nash Sutcliffe (NS) up to 0.54 for THg and 0.58 for MeHg). Model performance for all catchments was improved (NS up to 0.76 for THg and 0.85 for MeHg) by adding two to four parameters to represent seasonality in riparian soil water THg and MeHg concentrations profiles. These results are consistent with the hypothesis that riparian flow-pathways and seasonality in riparian soil concentrations are the major controls on temporal variation of THg and MeHg concentrations in low-order streams.

Ankle proprioception in children with cerebral palsy.

PURPOSE: There is no established clinical standard to evaluate ankle proprioception in children with cerebral palsy (CP). This study compared ankle position sense of children with CP to age-matched children who are typically developing (TD). METHODS: Children aged 6-17 years participated (15 CP, 58 TD). Using a custom-built device, the ankle was passively rotated to two positions for 25 trials. Using a psychophysical forced-choice paradigm, participants indicated which position was more plantarflexed. A psychometric function was fitted to the response data to determine the just noticeable difference (JND) threshold and the associated uncertainty (random error) for ankle position sense. RESULTS: Median JND thresholds for the CP group were elevated (CP: 4.3°, TD: 3.0°). Three children with CP exceeded the 95th percentile of TD. No differences in random error were found. CONCLUSION: This method assessed ankle proprioception relative to norm data and identified position sense impairments in children with CP. Using this method can provide data on proprioceptive status in CP, augmenting the assessment of motor impairment.

Association between chair stand strategy and mobility limitations in older adults with symptomatic knee osteoarthritis.

OBJECTIVE: To determine which lower limb strength and joint kinetic and kinematic parameters distinguish sit-to-stand (STS) performance of older adults with symptomatic knee osteoarthritis (OA) with higher and lower chair stand time. DESIGN: Cross-sectional. SETTING: Motion analysis laboratory. PARTICIPANTS: Individuals (N=49; 26 men, 23 women) aged 50 to 79 years (mean ± SD age, 64.7±8.1y) with radiographic knee OA and daily symptoms, stratified by chair stand times. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Lower limb strength and STS strategy. RESULTS: The chair stand times (mean ± SD) in the high-, moderate-, and low-functioning groups in men were 6.5±0.7, 8.6±0.7, and 11.5±1.3 seconds, respectively, and in women were 7.6±1.2, 10.0±0.5, and 12.8±1.8 seconds, respectively. Chair stand time (P=.0391) and all measures of lower limb strength (all P<.0001) differed by sex. In men, no strength measure differed between groups, whereas in women hip abductor strength on the more affected side differed between groups. In men, sagittal hip range of motion (ROM) (P=.0122) differed between groups, and there was a trend toward a difference in sagittal knee power (P=.0501) during STS, while in women only sagittal knee ROM (P=.0392) differed between groups. CONCLUSIONS: Higher- and lower-functioning adults with symptomatic knee OA appear to use different strategies when standing from a chair. Higher-functioning men flexed more at the hip and produced greater knee power than lower-functioning men. Higher-functioning women used less knee flexion than lower-functioning women. Since STS is an important mobility task, these parameters may serve as foci for rehabilitation aimed at reducing mobility limitations.

Medial Gastrocnemius Muscle Properties of Children With Cerebral Palsy After Different Tone Treatments: A Pilot Study.

OBJECTIVE: Spasticity in children with cerebral palsy can be managed by a spectrum of approaches, from conservative therapy, to temporary botulinum toxin A injections, to permanent transection of sensory nerves with a selective dorsal rhizotomy. This pilot study investigated whether these three tone management approaches are associated with histological and biochemical properties of the medial gastrocnemius. DESIGN: A convenience sample of children with cerebral palsy undergoing gastrocnemius lengthening surgery was enrolled. Intraoperative biopsies were obtained from three individuals (one each: minimal tone treatment; frequent gastrocnemius botulinum toxin A injections; previous selective dorsal rhizotomy). All individuals had plantarflexor contractures, weakness, and impaired motor control before the biopsy. RESULTS: Differences between participants were observed for muscle fiber cross-sectional area, fiber type, lipid content, satellite cell density, and centrally located nuclei. The most pronounced difference was the abundance of centrally located nuclei in the botulinum toxin A participants (52%) compared with the others (3-5%). Capillary density, collagen area and content, and muscle protein content were similar across participants. CONCLUSIONS: Several muscle properties seemed to deviate from reported norms, although age- and muscle-specific references are sparse. Prospective studies are necessary to distinguish cause and effect and to refine the risks and benefits of these treatment options.

Variability in lower extremity motor function in spina bifida only partially associated with spinal motor level.

PURPOSE: Previous studies have found motor function to correlate with spinal motor level and, accordingly, individuals with spina bifida are frequently categorized clinically in this manner. The aim of the current study was to describe how lower extremity functions including strength, selective motor control, and mirror movements vary by motor level in children and young adults with spina bifida. METHODS: A single center, retrospective, cross-sectional, descriptive study using data collected in the National Spina Bifida Patient Registry and by a gait laboratory was performed. RESULTS: Seventy-seven individuals with spina bifida were included with the majority having myelomeningocele (59 lumbar, 18 sacral motor level). Lower extremity strength and selective motor control varied to a certain extent with motor level. However, 90% of individuals showed strength or weakness in at least one muscle group that was unexpected based on their motor level. Mirror movements did not clearly vary with motor level. CONCLUSION: Lower extremity strength, selective motor control, and mirror movements in individuals with spina bifida were not entirely predicted by motor level. This highlights the possible need for an improved spina bifida classification system that describes not only spinal motor level but more clearly defines a particular individual's functional motor abilities.

Presence and predictors of pain after orthopedic surgery and associated orthopedic outcomes in children with cerebral palsy.

While children with cerebral palsy (CP) may undergo 8-22 orthopedic surgeries in their lifetime, little is known about the associated pain. We aimed to assess the pain presence before and one year after lower extremity orthopedic surgery, predictors of pain presence at follow-up, and the association between pain and orthopedic outcomes related to surgery. This retrospective study included 86 children with CP (M age = 10.0 years, SD = 3.2; range = 4.1-17.3 years, Gross Motor Functional Classification System (GMFCS) level I-III) who underwent orthopedic surgery and had completed questionnaires at gait analyses before (M = 2.7 months; range = 0.0-5.7) and after surgery (M = 11.8 months; range = 9.0-14.9). Pain presence, location, and Pediatric Outcomes Data Collection Instrument (PODCI) scores were documented before and after surgery at gait analyses. Pain prevalence was 60% at baseline and 56% at follow-up. Significant predictors of pain presence at follow-up included (1) pain presence at baseline (range of odds ratios [OR] across any/all locations = 3.22 to 15.54), (2) older age (range of OR for any pain, back, knee, and foot pain = 1.24-1.26), (3) female sex (decreased OR for males for ankle pain = 0.12), (4) having hip surgery (decreased OR for foot pain = 0.20), and (5) lower GMFCS level (OR for foot pain = 0.41). Changes in PODCI Sports and Physical Function scores were associated with changes in hip and knee pain (P < .03); PODCI scores worsened for patients who had pain at both time points and improved for patients who had pain at baseline but not follow-up. Pain was present for over half of the participants before and after orthopedic surgery. Pain presence at follow-up was predicted by pain presence at baseline. Pain and functional outcomes were correlated at follow-up. Prospective studies examining perioperative pain experience and factors predicting pain outcomes are warranted.

Freshwater unionid mussels threatened by predation of Round Goby (Neogobius melanostomus).

Indigenous freshwater mussels (Unionidae) are integral to riverine ecosystems, playing a pivotal role in aquatic food webs and providing ecological services. With populations on the decline worldwide, freshwater mussels are of conservation concern. In this study, we explore the propensity of the invasive Round Goby (Neogobius melanostomus) fish to prey upon indigenous freshwater mussels. First, we conducted lab experiments where Round Gobies were given the opportunity to feed on juvenile unionid mussels and macroinvertebrates, revealing rates and preferences of consumption. Several Round Gobies consumed whole freshwater mussels during these experiments, as confirmed by mussel counts and x-ray images of the fishes. Next, we investigated Round Gobies collected from stream habitats of the French Creek watershed, which is renowned for its unique and rich aquatic biodiversity. We developed a novel DNA metabarcoding method to identify the specific species of mussels consumed by Round Goby and provide a new database of DNA gene sequences for 25 indigenous unionid mussel species. Several of the fishes sampled had consumed indigenous mussels, including the Elktoe (non-endangered), Creeper (non-endangered), Long Solid (state endangered), and Rayed Bean (federally endangered) species. The invasive Round Goby poses a growing threat to unionid mussels, including species of conservation concern. The introduction of the invasive Round Goby to freshwaters of North America is shaping ecosystem transitions within the aquatic critical zone having widespread implications for conservation and management.

Perceived Limitations of Walking in Individuals With Cerebral Palsy.

OBJECTIVE: Impairments associated with cerebral palsy (CP) can affect gait quality and limit activity and participation. The purpose of this study was to quantify (1) which of 6 factors (pain, weakness, endurance, mental ability, safety concerns, balance) were perceived to limit walking ability the most in individuals with CP and (2) whether age or Gross Motor Function Classification System (GMFCS) level is related to that perception. METHODS: This cross-sectional study queried data from a gait laboratory database. Perceived walking limitation was quantified using a 5-point Likert scale ("never" to "all of the time"). Included were 1566 children and adults (mean age = 10.9 y [SD = 6.8]; range = 3.0-72.1 y) with CP (GMFCS level I: 502; II: 564; III: 433; IV: 67). RESULTS: Patients or caregivers perceived balance to limit walking ability to the greatest extent, followed by endurance, weakness, safety, mental ability, and pain. Balance was perceived to always limit walking ability in 8%, 22%, 30%, and 34% of individuals in GMFCS levels I through IV, respectively. Endurance was perceived to always limit walking ability in 5%, 13%, 13%, and 27% of individuals in GMFCS levels I through IV, respectively. There were minor differences in the perceived extent of limitation caused by the factors by GMFCS level. Only weak associations between age and pain, mental ability, safety, and balance were observed (Spearman rho = -0.13 to 0.24). CONCLUSION: Patients or caregivers perceived decreased balance and endurance to most strongly limit walking ability. Efforts should be made to clinically track how both perceived and objective measures of these limiting factors change with age and intervention. IMPACT: Following a patient- and family-centered care model, therapy that places greater emphasis on balance and cardiovascular endurance may have the greatest effect on walking ability for individuals with CP. Future research should quantify which therapeutic, surgical, and pharmacologic interventions minimize these impairments and optimize activity and participation. LAY SUMMARY: Balance and endurance are perceived to be the greatest factors limiting walking in people with CP. If you have CP, your physical therapist might emphasize balance and cardiovascular endurance to improve your walking ability.

Long-term functional outcomes after an external femoral derotation osteotomy in individuals with cerebral palsy.

BACKGROUND: It is unknown how a femoral derotation osteotomy (FDO) during childhood affects functional outcomes in adulthood among individuals with bilateral cerebral palsy (CP). RESEARCH QUESTIONS: How do long-term functional outcomes after an FDO compare to matched individuals who did not have an FDO? How do outcomes change over time? METHODS: We queried the gait laboratory database for individuals who underwent an external FDO in childhood and were currently ≥25 years old. Participants returned for a long-term analysis (gait, physical examination, functional tests, imaging, questionnaires). The matched non-FDO group included only individuals in Gross Motor Function Classification System levels I-II, yielding three groups (non-FDO I-II, FDO I-II, FDO III-IV). RESULTS: Sixty-one adults (11 non-FDO, 34 FDO I-II, 16 FDO III-IV) returned 13-25 years after baseline (non-FDO) or surgery (FDO). The non-FDO and FDO I-II groups were matched at baseline on most variables, except the FDO group had weaker hip abductors. At long-term, groups were similar on gait variables (median long-term hip rotation [primary outcome], non-FDO: -4°, FDO I-II: -4°, FDO III-IV: -5°), hip abduction test, fear of falling, and most pain measures despite anteversion being 29° greater in the non-FDO group. The FDO I-II group reported more falls than the non-FDO group. All groups improved on hip rotation, foot progression, and hip abductor strength. Speed and step length decreased/tended to decrease for all three groups. Hip abduction moment and gait deviation index did not change. Improvements in the FDO groups were maintained from short- to long-term. SIGNIFICANCE: These results challenge the notion that an FDO is necessary to correct mean stance hip rotation for higher functioning individuals since nearly identical results were achieved by adulthood in the non-FDO I-II group. However, an FDO provides improvement earlier and maintenance from short- to long-term. This should factor into the shared decision-making process.

Sources and transformations of nitrate from streams draining varying land uses: evidence from dual isotope analysis.

Knowledge of key sources and biogeochemical processes that affect the transport of nitrate (NO(3)(-)) in streams can inform watershed management strategies for controlling downstream eutrophication. We applied dual isotope analysis of NO(3)(-) to determine the dominant sources and processes that affect NO(3)(-) concentrations in six stream/river watersheds of different land uses. Samples were collected monthly at a range of flow conditions for 15 mo during 2004-05 and analyzed for NO(3)(-) concentrations, delta(15)N(NO3), and delta(18)O(NO3). Samples from two forested watersheds indicated that NO(3)(-) derived from nitrification was dominant at baseflow. A watershed dominated by suburban land use had three delta(18)O(NO3) values greater than +25 per thousand, indicating a large direct contribution of atmospheric NO(3)(-) transported to the stream during some high flows. Two watersheds with large proportions of agricultural land use had many delta(15)N(NO3) values greater than +9 per thousand, suggesting an animal waste source consistent with regional dairy farming practices. These data showed a linear seasonal pattern with a delta(18)O(NO3):delta (15)N(NO3) of 1:2, consistent with seasonally varying denitrification that peaked in late summer to early fall with the warmest temperatures and lowest annual streamflow. The large range of delta (15)N(NO3) values (10 per thousand) indicates that NO(3)(-) supply was likely not limiting the rate of denitrification, consistent with ground water and/or in-stream denitrification. Mixing of two or more distinct sources may have affected the seasonal isotope patterns observed in these two agricultural streams. In a mixed land use watershed of large drainage area, none of the source and process patterns observed in the small streams were evident. These results emphasize that observations at watersheds of a few to a few hundred km(2) may be necessary to adequately quantify the relative roles of various NO(3)(-) transport and process patterns that contribute to streamflow in large basins.