Alien Registration- Rodzen, Amela (Wilton, Franklin County)

https://digitalmaine.com/alien_docs/19573/thumbnail.jp

The Direct 3D Printing of Functional PEEK/Hydroxyapatite Composites via a Fused Filament Fabrication Approach

The manufacture of polyetheretherketone/hydroxyapatite (PEEK/HA) composites is seen as a viable approach to help enhance direct bone apposition in orthopaedic implants. A range of methods have been used to produce composites, including Selective Laser Sintering and injection moulding. Such techniques have drawbacks and lack flexibility to manufacture complex, custom-designed implants. 3D printing gets around many of the restraints and provides new opportunities for innovative solutions that are structurally suited to meet the needs of the patient. This work reports the direct 3D printing of extruded PEEK/HA composite filaments via a Fused Filament Fabrication (FFF) approach. In this work samples are 3D printed by a custom modified commercial printer Ultimaker 2+ (UM2+). SEM-EDX and µCT analyses show that HA particles are evenly distributed throughout the bulk and across the surface of the native 3D printed samples, with XRD highlighting up to 50% crystallinity and crystalline domains clearly observed in SEM and HR-TEM analyses. This highlights the favourable temperature conditions during 3D printing. The yield stress and ultimate tensile strength obtained for all the samples are comparable to human femoral cortical bone. The results show how FFF 3D printing of PEEK/HA composites up to 30 wt% HA can be achieved

The Surface Characterisation of Fused Filament Fabricated (FFF) 3D Printed PEEK/Hydroxyapatite Composites

Polyetheretherketone (PEEK) is a high-performance thermoplastic polymer which has found increasing application in orthopaedics and has shown a lot of promise for ‘made-to-measure’ implants via additive manufacturing approaches. However, PEEK is bioinert and needs to undergo surface modification to make it at least osteoconductive to ensure a more rapid, improved, and stable fixation that will last longer in vivo. One approach to solving this issue is to modify PEEK with bioactive agents such as hydroxyapatite (HA). The work reported in this study demonstrates the direct 3D printing of PEEK/HA composites of up to 30 weight percent (wt%) HA using a Fused Filament Fabrication (FFF) approach. The surface characteristics and in vitro properties of the composite materials were investigated. X-ray diffraction revealed the samples to be semi-crystalline in nature, with X-ray Photoelectron Spectroscopy and Time-of-Flight Secondary Ion Mass Spectrometry revealing HA materials were available in the uppermost surface of all the 3D printed samples. In vitro testing of the samples at 7 days demonstrated that the PEEK/HA composite surfaces supported the adherence and growth of viable U-2 OS osteoblast like cells. These results demonstrate that FFF can deliver bioactive HA on the surface of PEEK bio-composites in a one-step 3D printing process

Estimating connectivity in marine populations : an empirical evaluation of assignment tests and parentage analysis under different gene flow scenarios

Author Posting. © Blackwell Publishing, 2009. This is the author's version of the work. It is posted here by permission of Blackwell Publishing for personal use, not for redistribution. The definitive version was published in Molecular Ecology 18 (2009): 1765-1776, doi:10.1111/j.1365-294X.2009.04109.x.The application of spatially explicit models of population dynamics to fisheries management and the design marine reserves network systems has been limited due to a lack of empirical estimates of larval dispersal. Here we compared assignment tests and parentage analysis for examining larval retention and connectivity under two different gene flow scenarios using panda clownfish (Amphiprion polymnus) in Papua New Guinea. A metapopulation of panda clownfish in Bootless Bay with little or no genetic differentiation among 5 spatially discrete locations separated by 2-6km provided the high gene flow scenario. The low gene flow scenario compared the Bootless Bay metapopulation with a genetically distinct population (Fst = 0.1) located at Schumann Island, New Britain, 1,500km to the north-east. We used assignment tests and parentage analysis based on microsatellite DNA data to identify natal origins of 177 juveniles in Bootless Bay and 73 juveniles at Schumann Island. At low rates of gene flow, assignment tests correctly classified juveniles to their source population. On the other hand, parentage analysis led to an overestimate of self-recruitment within the two populations due to the significant deviation from panmixia when both populations were pooled. At high gene flow (within Bootless Bay), assignment tests underestimated self-recruitment and connectivity among subpopulations, and grossly overestimated self-recruitment within the overall metapopulation. However, the assignment tests did identify immigrants from distant (genetically distinct) populations. Parentage analysis clearly provided the most accurate estimates of connectivity in situations of high gene flow.We thank ARC Centre of Excellence, the National Science Foundation (OCE 0424688), the Coral Reef Initiatives for the Pacific (CRISP), the TOTAL Foundation, Populations Fractionées et Insulaires (PPF EPHE) and GEF/World bank’s CRTR program (Connectivity working group) for financial support

Alien Registration- Rodzen, Mary M. (Monmouth, Kennebec County)

https://digitalmaine.com/alien_docs/16374/thumbnail.jp

Alien Registration- Rodzen, Amela (Wilton, Franklin County)

https://digitalmaine.com/alien_docs/19573/thumbnail.jp

Preservation of Genetic Variation within Aquaculture Stocks of White Sturgeon (Acipenser transmontanus)

Nine tetramer [GATA]n microsatellite systems were developed for use in the white sturgeon, Acipenser transmontanus. We report inheritance patterns for these nine systems, which range from one possible disornic system to tetrasomy and octosomy, with some systems containing null alleles. Due to the complex modes of inheritance underlying these systems and the highly duplicated nature of the genome, we propose each allele be scored as its own dominant marker, similar to AFLPs or RAPDs. The utility of this method is validated by the observation that individual alleles within a microsatellite system generally fit the expectation for independent transmission and fit the expected transmission frequency for single copy nuclear markers

Depression in children: A growing concern

ABSTRACT Purpose: The purpose of this article is to review the available scientific data regarding diagnosis, screening, risk factors, treatment, and management of depression in children and adolescents. Method: Using a PubMed search engine with terms depression, adolescents, children, evaluation, management, treatment, diagnosis, screening, risks, a literature search was conducted. Twenty-one scholarly articles were retrieved and will serve for the purpose of review in this article. Results: Depression continues to be a challenging illness to diagnose in children and adolescents. Awareness and understanding of this disease process and its risk factors can help primary care providers diagnose and implement timely treatment plan. Conclusion: The rising risk of depression in children and adolescents is a major concern in our healthcare system and growing concern around the world. By recognizing this complex disease process and establishing early diagnosis, treatment plan, and arranging a timely referral to mental health specialists, may save many innocent lives. Although challenging to diagnose, considering this illness when differentiating chronic somatic complaints in children and adolescents or other behavioral or mental health concerns, can lead to correct diagnosis. Importantly, although depression is a treatable illness, if unrecognized and undiagnosed early, it becomes a life threatening illness. With increased awareness and directing our concentration to disease prevention, the mortality rate from suicidality can improve as well as sequelae that often extend into adulthood. Keywords: Depression, Children, Adolescent