Variation of the synarcual in the California Ray, Raja inornata (Elasmobranchii: Rajidae)

Seven juvenile specimens of Raja inornata were CT scanned and digitally modeled to examine the variation of synarcual morphology with changing size. The synarcual is a highly variable skeletal element across batoids with great potential for use in phylogenetic studies. Results show that as R. inornata increases in body size, the synarcual becomes more elongate and laterally compressed. Projections of the synarcual become more pronounced with increasing size as well. The synarcual of R. inornata is narrower than that of R. erinacea. There appears to be a correlation between median crest width and synarcual spine size. Also, in the context of higher-level batoid phylogenetics, the morphologically ventral position of the u-shaped lateral stay is considered primitive

Cadaveric and Chart Retrospective on Shoulder Variation: Morphology and Pain

Osteopathic Manipulative Treatment (OMT) is a category of several types of manual techniques used by osteopathic physicians. According to the osteopathic tradition, structure and function are intimately related. This project examined the relationship between shoulder structure and function in an osteopathic framework, with a specific goal to understand how the structure of the acromion affects the development of shoulder injuries. For the first part of this project, cadaveric dissections were performed and muscle diameters were taken of structures within the subacromial space. The second part of this project assessed the efficacy of OMT in shoulder somatic dysfunction for patients treated at Philadelphia College of Osteopathic Medicine (PCOM)

The effect of physical activity on vitamin D: A systematic review and meta-analysis of intervention studies in humans

Objectives: Cross-sectional studies demonstrate a positive association between higher physical activity and serum 25-hydroxyvitamin D (25(OH)D) concentration. However, whether this association is causal is unclear. We conducted a systematic review to identify intervention studies that examined the effect of physical activity on serum 25(OH)D concentration in humans. Study design: Systematic review and meta-analysis. Methods: We searched PubMed, Scopus and Web of Science to identify full-text peer-reviewed articles published in English from inception until January 2023. Eligible studies were randomised controlled trials or quasi-experimental studies. We used random effects meta-analysis to calculate the weighted mean difference (WMD) in the change in 25(OH)D concentration between physical activity and control groups. We used the revised Cochrane risk-of-bias tool for randomized trials (RoB 2) to assess the methodological quality of included studies. Results: We included 32 articles in the systematic review and 24 in the meta-analysis. The intervention varied from resistance and weight-bearing exercises (n = 13) to aerobic exercises (n = 10), moderate and moderate-to-vigorous exercises (n = 5), aquatic exercise (n = 2), and multicomponent traditional exercises (n = 2) (Tai Chi and Yijinjing). The WMD in 25(OH)D in the physical activity and control groups was 9.51 and 4.87, respectively (between-group mean difference 4.64, p = 0.002). However, the difference was only evident in studies that implemented the intervention outdoors (n = 3; between-group mean difference 17.33, p < 0.0001); when the intervention was indoors there was no significant effect of physical activity on 25(OH)D (n = 16; between-group mean difference 1.80, p = 0.113). Conclusions: This meta-analysis of physical activity interventions in humans showed that physical activity does not lead to increased 25(OH)D independently of time outdoors. However, most studies were under-powered, in many the exercise was low intensity, and vitamin D was not the primary outcome

Plastination Procedure @ PCOM: Current Practice and Future Uses

Introduction: Since its invention by German anatomist Gunther von Hagens, the process of forced-impregnation plastination of organic specimens has become the standard for the preservation of biological tissue specimens. This practice serves as the most practical method to preserve these specimens for study and is utilized at PCOM regularly for this purpose. During the steps of plastination, aqueous and lipid tissues are replaced by a curable polymer to produce plastinates that do not decompose, can be handled without gloves, and retain most characteristics of the original specimens. For decades, PCOM used this method to prepare a permanent teaching collection in support of medical education. In the last five years, the lab has been reactivated and prepares specimens for allied health professional education, enrichment of the Doctor of Osteopathy curriculum, and outreach at regional institutions (e.g., The Franklin Institute, The Nebinger School, etc.). Objectives: The purpose of this poster is to inform the PCOM community of current plastination practices and suggest future uses. Methods: To prepare specimens for plastination, they must be preserved in fixative. We currently dissect and stage all tissues after the fixative process. Dissections are prepared by work-study students at PCOM who have completed the relevant anatomy course (interested students please contact Dr. Claeson). After fixation, tissues are dehydrated in progressively more concentrated washes of cold-temperature acetone (-20ºC) until concentration is between 98-100%. After dehydration, they are placed into a silicone polymer bath and brought to room temperature. The room temperature bath technique is the primary deviation from von Hagen (1977). Once at room temperature in the bath, vacuum pressure is used to replace the acetone that fills each cell with silicone. A hardening agent is then administered to finish the process. Results & Conclusions: Current initiatives have included building a collection of heart specimens to support a cardiac workshop which pairs anatomy and physiology. Most recently, a brain anatomy collection is being built. Brain specimens include axial cross sections, whole and half brains, and pathological specimens. These specimens are currently used at many outreach events and will be incorporated into a featured anatomy series as part of the medical school curriculum. Future research initiatives may also begin via current practices

Salmon and marine-derived nutrient effects on primary and secondary trophic levels

The purpose of this study was to understand the influence of organic material and nutrients from spawning salmon and supplemented salmon carcasses on stream food webs. My study objectives were to examine 1) assimilation of salmon-derived nutrients (SDN) by producers and consumers in the food web, 2) epilithic biofilm productivity, 3) leaf-litter decomposition rates, and 4) benthic insect density and biomass, in areas with and without spawning salmon and also compare these responses downstream and upstream of salmon carcasses. My hypothesis was that production-related measures of organisms that assimilate SDN would increase in response to spawning salmon or added carcasses. Biofilm, leaf-litter, and macroinvertebrate responses to salmon were evaluated during two field studies in the Wind River basin of southwest Washington. The first study (July - November 2002) was observational and compared responses from a reach with spawning Chinook (Onchorhychus tshawytscha) to two reaches upstream of spawning salmon. In the second experiment (July - October 2003), Chinook carcasses were added and retained within three streams in which responses were measured at increasing distances downstream of the salmon (10m, 50m, 150m, and 250m) and compared to responses measured upstream of salmon. Analysis of stable carbon and nitrogen isotopes demonstrated that SDN from both naturally spawned salmon and manually added carcasses were incorporated into the stream food webs by epilithic biofilm, most benthic insects (scrapers, collectors, and predators), and juvenile steelhead. However, I was unable to detect changes in primary and secondary production-related measures in response to naturally spawned salmon. This observational study was limited in its design and the carcass-addition experiment in the second year provided greater resolution about secondary consumers and spatially explicit responses. Results from the carcass-addition study showed a non-significant increase in epilithic biofilm chlorophyll a levels in October, but no effect on biofilm ash-free-dry-mass. Leaf decomposition rates in September were significantly faster at one site downstream of added carcasses, but shredding insects did not increase in density or biomass, and shredders did not assimilate SDN. Of the nutrients measured (NH⁴-N, NO³-N, NO²-N, DON, SRP, DOC), only ammonium increased significantly downstream of added carcasses. Total benthic insect density significantly increased in September whereas total insect biomass was highly variable and no changes were detected. Densities and/or biomass of some scraping (Heptageniidae) and collecting (Chironomidae and Elmidae) benthic insects increased in September and/or October. Predatory insects did not increase in density or biomass, though they did assimilate SDN. These results suggest a potential bottom-up cascade in which increased primary production was reduced by an increase in secondary consumers. In general, benthic responses were highest within 50 m downstream of added carcasses. Salmon-derived nitrogen was observed in epilithic biofilm and some benthic insects collected 150 m downstream of carcasses. The timing of responses varied depending on the mode of consumption. In limnephiled caddis larvae colonizing carcasses, the SDN signal peaked just 2 weeks after carcasses were added. Among insects that indirectly consumed SDN, the signal peaked 2 months post-carcass addition. Benthic insect production peaked 1.5 months after carcasses were added, with most measures returning to background levels one month later. Augmenting streams with salmon carcasses may influence several ecosystem components, but responses may be spatially localized around carcasses and persist for only a short time after carcasses are added

Conus medullaris termination in adult females

Objective: The primary objective of this study was to determine the termination level of the spinal cord in a sample population of adult female cadavers. Introduction: The conus medullaris represents the tapered, distal-most end of the spinal cord. It tends to be found somewhere between the L1-L2 lumbar vertebrae and can sometimes be higher or lower. Studies report the conus medullaris can be found anywhere from the lower third of T11 to the upper third of L3 with the average termination point around the lower third of L1. We aim to describe the level of conus medullaris termination in a sample of female cadavers. Methods: Twenty-four female cadavers were dissected as part of the Doctor of Osteopathic Medicine curriculum at the Philadelphia College of Osteopathic Medicine. The end of the conus medullaris was defined as the point where tapering ends distal to the last branches of the posterior nerve rootlets. Using the articulation of the 12th rib as a landmark the termination of the conus medullaris was noted to be either at the level of an intervertebral disc or vertebral body. In the latter cases the vertebral body was divided into upper, middle, and lower thirds. Results: Conus Medullaris termination ranged from the T12-L1 intervertebral disc to the L2-L3 intervertebral disc. The L1-L2 intervertebral disc was the most common termination point with 42% of cadavers demonstrating spinal cord termination at this level. Conclusions: These results demonstrate that there is variation of spinal cord termination, which can play a role in lumbar punctures, spinal anesthesia, and obstetric anesthesia. Due to the risk of cord damage it is imperative to perform any sort of anesthetic procedure fully below the level of L3 in the L3-L4 space or L4-L5 space. An epidural injection above the level of L3 may cause severe spinal cord damage if there is dural puncture and an anatomical variant in which the conus medullaris extends to the L3 level

Giant lasing effect in magnetic nanoconductors

We propose a new principle for a compact solid-state laser in the 1-100 THz regime. This is a frequency range where attempts to fabricate small size lasers up till now have met severe technical problems. The proposed laser is based on a new mechanism for creating spin-flip processes in ferromagnetic conductors. The mechanism is due to the interaction of light with conduction electrons; the interaction strength, being proportional to the large exchange energy, exceeds the Zeeman interaction by orders of magnitude. On the basis of this interaction, a giant lasing effect is predicted in a system where a population inversion has been created by tunneling injection of spin-polarized electrons from one ferromagnetic conductor to another -- the magnetization of the two ferromagnets having different orientations. Using experimental data for ferromagnetic manganese perovskites with nearly 100% spin polarization we show the laser frequency to be in the range 1-100 THz. The optical gain is estimated to be of order 10^7 cm^{-1}, which exceeds the gain of conventional semiconductor lasers by 3 or 4 orders of magnitude. A relevant experimental study is proposed and discussed.Comment: 4 pages, 3 figure

Revision of the Eocene \u27Platyrhina\u27 species from the Bolca Lagerstätte (Italy) reveals the first panray (Batomorphii: Zanobatidae) in the fossil record

The fossil-Lagerstätte of Bolca (Italy) is well known for the diversity and exquisite preservation of its bony and cartilaginous fishes documenting tropical shallow-water marine environments associated with coral reefs in the western Tethys during the early Eocene. In this study, the taxonomic, systematic and phylogenetic position of two batoid species traditionally assigned to the living thornback ray genus Platyrhina is re-evaluated. †Platyrhina bolcensis Heckel, 1851 is recognized as a separate species of the Platyrhinidae because of its plate-like antorbital cartilage with an irregular outline and a small horn on the nasal capsules. Also, the rostral cartilage does not reach the anterior border of the disc. Support for the placement of this species within the new genus †Eoplatyrhina gen. nov. is based on a combination of morphological and meristic features (e.g. nasal capsules at right angles to the rostrum; large space between the hyomandibulae and mandibular arch; approximately 132 vertebral centra; 15–16 rib pairs; 81–87 pectoral radials; 18–21 pelvic radials; short, straight and stout claspers; 40–50 caudal-fin radials; thorns absent). A second species, †Platyrhina egertoni (De Zigno, 1876), is more closely related to the living panray Zanobatus than Platyrhina and is assigned here to †Plesiozanobatus gen. nov. because of a combination of characters that support its placement within the family Zanobatidae (tail stout and short, distinctly demarcated from disc; two dorsal fins and complete caudal fin; small dermal denticles and scattered thorns covering disc and tail; rostral cartilage absent; nasal capsules without horn-like processes; mesopterygium absent). The systematic position of a third taxon, †Platyrhina gigantea (Blainville, 1818), is currently impossible to establish due to the poor preservation of the only known specimen, and therefore we propose to consider it a nomen dubium. Palaeoecological and biogeographic features of the Eocene platyrhinids and zanobatids from Bolca are also discussed