Experimental Study on Three-Degree-of-Freedom Ventilated Cavities for Underwater Vehicles Considering the Air Mass near the Tube

OBJECTIVE: Sagittal strip craniectomy, is widely used for the treatment of sagittal craniosynostosis to normalize head shape, yet few 3D studies have investigated the rate and location of shape change following surgery. The aim of this study was to determine the velocity and location of the major shape changes after limited incision sagittal strip craniectomy with barrel staving and postop helmet therapy. METHODS: After IRB approval, a retrospective chart review of all patients treated with strip craniectomy and barrel stave’s at our institution was undertaken. Selection criteria included: 1) diagnosis of sagittal craniosynostosis; 2) treatment age less than 200 days; 3) compliance with and completion of helmet therapy through 1 year of age. Results of cranial index (CI), maximal anterior-posterior length and maximal width were obtained from preoperative 3D surface scans to the end of helmet therapy. To determine the stabilization of CI, longitudinal CI measurements were obtained during helmet therapy. Then the measurements were fitted using an exponential equation and the end point of CI was estimated when the curve stabilizes at a change less than 0.01 CI/day. Postoperative results were classified as excellent (CI > 80), good (CI 70–80) and poor (CI < 70)1. In addition, the change in head shape from preoperative to postoperative was evaluated using 3D analysis. RESULTS: 20 patients met selection criteria (6 Female, 14 male). The average age of surgery was 109.2 ± 19.7 days (range 83–146). There was a significant increase in the CI from 71.7 ± 3.8 (range 63–77.9.) preoperative to 81.1 ± 4.2 (range 73–89.8) postoperative. 60% of patients had an excellent result and 40% had a good result. The average duration of postoperative helmet therapy was 334 ± 97.8 days (range 132–514.). The average postoperative time until stabilization of cranial index was 52.4 ± 24.7 days. 3D analysis demonstrated the posterior third to have the most change in shape, and this was both in skull height and anterior-posterior dimension. No postoperative complications occurred. CONCLUSIONS: Limited incision sagittal strip craniectomy with barrel staving and postop helmet therapy produces a rapid change in CI and head shape. This suggests that the duration of helmet therapy may be shortened which could impact cost and burden of care. Further studies are needed to determine the effects of varied duration of postoperative helmet orthotic therapy and head shape. REFERENCES: 1. Jimenez DF, Barone CM: Endoscopic technique for sagittal craniosynostosis. Child Nervous System 28:1333–39, 2012

Sir: Since the inception of the Back to Sleep campaign in the early 1990s, there has been a well-documented drop in the incidence of sudden infant death syndrome.1 There has also been a concomitant, well-documented rise in the number of plagiocephaly cases.2 Helmet molding therapy with orthosis has become an accepted treatment for deformational plagiocephaly. No studies have compared changes in three-dimensional objective measures in a patient's head shape with subjectively observed outcome. In this study, we investigated the actual versus perceived improvements from helmet molding therapy for deformational plagiocephaly using three-dimensional laser head scans. During the initial clinic visit, parents of 61 deformational plagiocephaly patients were asked to rate their child's head shape and ear position on a scale of 1 to 10, with 1 being abnormal and 10 representing normal. After their child's helmet molding therapy, parents were again asked to rate their child's head shape and ear position. A matched cohort of 91 children who underwent helmet molding therapy for the treatment of deformational plagiocephaly were also identified. Patients' charts were reviewed and topographic laser head scans were acquired using a STARscanner (Orthomerica, Orlando, Fla.). Laser scans were analyzed for each patient before and after helmet molding therapy. Cranial vault asymmetry index was calculated from the oblique measurements on head scans. The results of this study are presented in Figures 1 and 2.Fig. 1.: Mean actual changes in cranial vault asymmetry index and ear offset as measured by topographic laser head scans. A cranial vault asymmetry index below 3.5 is generally indicative of normal symmetry.Fig. 2.: Parents were asked to rate their child's head shape and ear position before and after helmet molding therapy. Ratings were based on a scale of 1 to 10, with 1 representing abnormal and 10 representing normal.The STARscanner provides numerous measurements on head shape; however, the cranial vault asymmetry index was selected because it normalizes for head size, allowing for comparison of head shapes independent of changes in head size attributable to age.3 In this study, helmet molding therapy resulted in a mean change in the cranial vault asymmetry index of 2.4 percent and a posttherapy mean cranial vault asymmetry index of 4.8. Although this degree of change in head shape still corresponded with noticeable asymmetry, parents viewed these results positively. After helmet molding therapy, parents rated their child's head shape as 7.88 on a scale of 1 to 10, with 1 being abnormal and 10 representing normal. Before therapy, the mean parental rating was 2.99. However, the improvements in ear position that parents perceived (7.75 following molding compared with 3.75 before therapy) were similar in magnitude to the changes in head shape despite less impressive changes in actual ear offset. The actual change in ear offset measured on topographic scans was only 0.2 mm. Although measurable asymmetry remains following helmet therapy for the correction of posterior positional plagiocephaly, appreciable and statistically significant changes are observed. These changes are viewed as significant by parents, although the objective measurements appear minimal. These data can be used in combination with pre–helmet molding head scans to inform parents of expected changes from helmet orthosis. Future longitudinal prospective studies will need to address the true utility of helmet molding therapy as compared with lack of helmet orthosis in correction of posterior positional plagiocephaly. DISCLOSURE The authors have no financial interests to disclose. Evan B. Katzel, B.A. Peter F. Koltz, M.D. Hani Sbitany, M.D. Christine Emerson, N.P. John A. Girotto, M.D. Division of Plastic and Reconstructive Surgery Department of General Surgery University of Rochester Medical Center Rochester, N.Y.

OBJECTIVE Outcome studies for sagittal strip craniectomy have largely relied on the 2D measure of the cephalic index (CI) as the primary indicator of head shape. The goal of this study was to measure the 2D and 3D changes in head shape that occur after sagittal strip craniectomy and postoperative helmet therapy. METHODS The authors performed a retrospective review of patients treated with sagittal strip craniectomy at their institution between January 2012 and October 2015. Inclusion criteria were as follows: 1) isolated sagittal synostosis; 2) age at surgery < 200 days; and 3) helmet management by a single orthotist. The CI was calculated from 3D images. Color maps and dot maps were generated from 3D images to demonstrate the regional differences in the magnitude of change in head shape over time. RESULTS Twenty-one patients met the study inclusion criteria. The mean CI was 71.9 (range 63.0-77.9) preoperatively and 81.1 (range 73.0-89.8) at the end of treatment. The mean time to stabilization of the CI after surgery was 57.2 ± 32.7 days. The mean maximum distances between the surfaces of the preoperative and 1-week postoperative and between the surfaces of the preoperative and end-of-treatment 3D images were 13.0 ± 4.1 mm and 24.71 ± 6.83 mm, respectively. The zone of maximum change was distributed equally in the transverse and vertical dimensions of the posterior vault. CONCLUSIONS The CI normalizes rapidly after sagittal strip craniectomy (57.2 days), with equal distribution of the change in CI occurring before and during helmet therapy. Three-dimensional analysis revealed significant vertical and transverse expansion of the posterior cranial vault. Further studies are needed to assess the 3D changes that occur after other sagittal strip craniectomy techniques.

Pediatric care providers, pediatricians, pediatric subspecialty physicians, and other health care providers should be able to recognize children with abnormal head shapes that occur as a result of both synostotic and deformational processes. The purpose of this clinical report is to review the characteristic head shape changes, as well as secondary craniofacial characteristics, that occur in the setting of the various primary craniosynostoses and deformations. As an introduction, the physiology and genetics of skull growth as well as the pathophysiology underlying craniosynostosis are reviewed. This is followed by a description of each type of primary craniosynostosis (metopic, unicoronal, bicoronal, sagittal, lambdoid, and frontosphenoidal) and their resultant head shape changes, with an emphasis on differentiating conditions that require surgical correction from those (bathrocephaly, deformational plagiocephaly/brachycephaly, and neonatal intensive care unit-associated skill deformation, known as NICUcephaly) that do not. The report ends with a brief discussion of microcephaly as it relates to craniosynostosis as well as fontanelle closure. The intent is to improve pediatric care providers' recognition and timely referral for craniosynostosis and their differentiation of synostotic from deformational and other nonoperative head shape changes.

Chlamydoselachus anguineus, Garman 1884, commonly called the frilled shark, is a deep‐sea shark species occurring up to depths of 1300 m. It is assumed to represent an ancient morphotype of sharks (e.g., terminal mouth opening, more than five gill slits) and thus is often considered to represent plesiomorphic traits for sharks. Therefore, its early ontogenetic developmental traits are important for understanding the evolution of its particular phenotype. Here, we established six stages for prenatal embryos and used linear measurements and geometric morphometrics to analyse changes in shape and size as well as their timing during different embryonic stages. Our results show a change in head shape and a relocation of the mouth opening at a late stage of development. We also detected a negative allometric growth of the head and especially the eye compared to the rest of the body and a sexual dimorphism in total body length, which differs from the known data for adults. A multivariate analysis of covariance shows a significant interaction of shape related to the logarithm of centroid size and developmental stage. Geometric morphometrics results indicate that the head shape changes as a covariate of body size while not accounting for differences between sexes. The growth pattern of stages 32 and 33 indicates a shift in head shape, thus highlighting the moment in development when the jaws start to elongate anteriorly to finally achieve the adult condition of terminal mouth opening rather than retaining the early embryonic subterminal position as is typical for sharks. Thus, the antero‐terminal mouth opening of the frilled shark has to be considered a derived feature.

Background: The cephalic index and head circumference are important anthropometric parameters that can provide insights into the physical characteristics and growth patterns of populations. There is dearth of data on Cephalic Index and Head circumference of Igbo Children and Adolescents. Method: This study examined 725 Igbo children and adolescents aged 5 to 19 years in Enugu, South-eastern Nigeria, using a cross-sectional approach. Results: The majority of participants exhibited mesocephalic head shape (43.2%), with brachycephalic and dolichocephalic shapes observed in 32.7% and 14.2% of the population, respectively. Mean head circumference increased with age in both sexes. Cephalic indices in boys under 12 and girls under 15 were below 80 but increased above these ages. Changes in head shape, potentially towards brachycephalization, were noted as children grew. Significant correlations were found between head circumference and cephalic index with age, height, weight, and body mass index, suggesting their relevance in forensic and anthropological investigations. Conclusion: Our results indicate diversity in head shapes and sizes, with mesocephalic heads being most common. As age increases, head circumference also tends to increase, and changes in head shape towards brachycephalization was observed. These findings underscore the importance of understanding anthropometric variations in different populations and suggest avenues for further research, particularly longitudinal studies, to explore the factors influencing these patterns.

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 43:31-39 (2010) - DOI: https://doi.org/10.3354/cr00878 Contrasting effects of environmental factors during larval stage on morphological plasticity in post-metamorphic frogs Miguel Tejedo1,*, Federico Marangoni1,2, Cino Pertoldi3, Alex Richter-Boix4, Anssi Laurila4, Germán Orizaola4, Alfredo G. Nicieza5, David Álvarez5, Iván Gomez-Mestre5,6 1Department of Evolutionary Ecology, Estación Biológica de Doñana, CSIC, Avda. Américo Vespucio s/n, 41092 Sevilla, Spain 2Laboratorio de Genética Evolutiva, FCEQyN-UnaM/CONICET, Félix de Azara 1552, 6to Piso 3300 Posadas – Misiones, Argentina 3Department of Ecology and Genetics, Institute of Biological Sciences, University of Aarhus, Denmark 4Department of Population Biology and Conservation Biology, Evolutionary Biology Centre (EBC), Uppsala University, Norbyvägen 18 D, 752 36 Uppsala, Sweden 5Ecology Unit, Department of Biology of Organisms and Systems, University of Oviedo, 33071 Oviedo, and Cantabrian Institute of Biodiversity (ICAB), Spain 6Department of Wetland Ecology, Estación Biológica de Doñana, CSIC, Avda. Américo Vespucio s/n, 41092 Sevilla, Spain *Email: tejedo@ebd.csic.es ABSTRACT: In organisms with complex life cycles, environmentally induced plasticity across sequential stages can have important consequences on morphology and life history traits such as developmental and growth rates. However, previous research in amphibians and other ectothermic vertebrates suggests that some morphological traits are generally insensitive to environmental inductions. We conducted a literature survey to examine the allometric responses in relative hind leg length and head shape of post-metamorphic anuran amphibians to induced environmental (temperature, resource level, predation and desiccation risk) variation operating during the larval phase in 44 studies using 19 species. To estimate and compare plastic responses across studies, we employed both an index of plasticity and effect sizes from a meta-analysis. We found contrasting trait responses to different environmental cues. Higher temperatures increased development more than growth rate and induced smaller heads but not overall shifts in hind leg length. In contrast, an increment in resource availability increased growth more than development, with a parallel increase in hind leg length but no change in head shape. Increases in predation risk decreased both development and growth rates and slightly reduced relative hind leg length, but there was no change in head shape. Pond desiccation induced quick development and low growth rates, with no changes in morphology. Across environments, both hind leg and head shape plasticity were positively correlated with growth rate plasticity. However, plasticity of developmental rate was only correlated with head shape plasticity. Overall, these results suggest that environmental trends predicted by global warming projections, such as increasing pond temperature and accelerating pond desiccation, will significantly influence hind leg and head morphology in metamorphic frogs, which may affect performance and, ultimately, fitness. KEY WORDS: Morphology · Plasticity · Temperature · Resources · Pond desiccation · Predation risk · Meta-analysis · Global warming Full text in pdf format Supplementary material PreviousNextCite this article as: Tejedo M, Marangoni F, Pertoldi C, Richter-Boix A and others (2010) Contrasting effects of environmental factors during larval stage on morphological plasticity in post-metamorphic frogs. Clim Res 43:31-39. https://doi.org/10.3354/cr00878 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 43, No. 1-2. Online publication date: August 05, 2010 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2010 Inter-Research.

Three-dimensional assessments versus perceptions of skull deformation in infants

Prey selection in many species is known to change ontogenetically, suggesting that associated changes in trophic structure may also be important. Several studies have examined relationships between prey selection and the size of trophic structures; however, few have explored these changes over ontogeny or the effects that they may have on a species broader ecology. The present study addressed this issue by examining relationships between changes in head size and prey selection in juveniles and adults from three populations of the python Morelia viridis and related them to changes in sexual maturity and ontogenetic changes in colour (OCC). Our scaling data for head size showed that juveniles and adults scaled mostly with negative allometry, and allometric slopes were significantly different before and after OCC. The change in head shape allometry was strongly associated with changes in prey selection from ectothermic to endothermic prey and with OCC in two of the three populations studied. OCC in the other population varied widely and may be the result of isolation on an oceanic island. Negatively allometric head growth is common in vertebrates and may serve a functional role in M. viridis by reducing the maximum ingestible prey size in adults, thus aiding arboreality. Our data do not allow us to test which of these changes have causal or resultant effects on one another; however, we suggest they may be part of an overall evolutionary defence‐foraging strategy that circumvents costs imposed by restricting foraging opportunities to certain habitats. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, , ••‐••.

Cone beam CT for the assessment of bone microstructure to predict head shape changes after spring-assisted craniosynostosis surgery

The relationship of sonographic femur length to biparietal diameter (BPD) in utero may be useful in detecting short-limb dwarfism, hydrocephaly, microcephaly, and measurement errors. Because BPD can be adversely affected by head shape changes (e.g., dolichocephaly), falsely high or low values of femur length/BPD could result. Because head circumference is less affected by head shape changes than is BPD, it should be a better standard of head size against which to judge limb length. The authors report normal values for the relationship between femur length and head circumference, based on a cross-sectional analysis of 361 normal fetuses (15-42 weeks) using real-time ultrasound.

Longitudinal, Three-Dimensional Analysis of Head Shape in Children with and without Deformational Plagiocephaly or Brachycephaly

Polymorphism in the ant Pogonomyrmex badius was studied using morphometric analysis. Head shape in P. badius was compared to 14 closely related monomorphic Pogonomyrmex believed to differ in worker morphology due to character displacement. Head shape in P. badius and two polymorphic Solenopsis species, one known to have a seed-milling caste (S. geminata) and the other continuously polymorphic (S. invicta), was also compared. Monomorphic species of Pogonomyrmex differed from P. badius in the rules of transformation that accompany changes in worker head size. Although workers of the Pogonomyrmex species studied changed in size primarily by increases in the area of the occipital region and the width of the head, polymorphic P. badius workers showed a significantly greater allometric increase in the occipital region. The comparative morphometrics of P. badius, monomorphic Pogonomyrmex and two polymorphic Solenopsis species did not support the hypothesis that size-related changes in head shape are due to competitive displacement, because head shapes in P. badius were not similar to head shapes in the monomorphic Pogonomyrmex. In contrast, results suggest that a dietary change may have led to the evolution of polymorphism in P. badius through selection for a seed-milling caste. This conclusion is supported by additional analyses that indicate the existence of two distinct modal head shapes in the caste distribution of P. badius and S. geminata, suggesting that bimodal shape variation might be a common evolutionary response to seed processing.

Lattice structures in ‘pore shape-stiffness’ framework: A ‘porosity-moment of inertia’ based interpretation

Actual and perceived improvements from helmet molding therapy for deformational plagiocephaly are demonstrated here. Effective communication of these data by craniofacial teams can help avoid unrealistic expectations and inform parents of expected outcomes. Parents of 61 patients with plagiocephaly were asked to rate their children's head shape and ear position before and after helmet therapy (a score of 1 being abnormal and 10 being normal). Topographic laser head scans for an aged-matched cohort of 91 patients with deformational plagiocephaly were acquired. Cephalic ratio, overall symmetry ratio, radial symmetry index, ear offset, and left and right oblique were recorded before and after molding. The cranial vault asymmetry index (CVSI) score was calculated. Parent ratings before and after molding, respectively, were head shape 2.99 ± 1.50 (mean ± SD) versus 7.88 ± 1.64 (p < .0001) and ear position 3.75 ± 2.5 versus 7.73 ± 2.34 (p < 0.0001). Measurements before and after molding were cephalic ratio 0.89 ± 0.07 versus 0.87 ± 0.08 (p < .0001), overall symmetry index 0.87 ± 0.05 versus 0.90 ± 0.04 (p < .0001), radial symmetry index 59.9 ± 26.9 mm versus 46.3 ± 25.1 mm (p < .0001), CVSI 7.2 ± 3.75 versus 4.8 ± 2.8 (p < .0001), and ear offset 5.7 versus 5.5 mm (p = .58). Helmet molding produces reproducible changes in head shape. Despite relatively small actual changes on topographic laser imaging, parents perceive a large correction in head shape and ear position following helmet molding. Craniofacial teams can use these data and head scans before helmet molding to provide parents with realistic expectations for the outcome of their child's helmet molding therapy.