Subsea approach to work systems development

Self-contained undersea working environments with applications to space station EVA environments are discussed. Physiological limitations include decompression, inert gas narcosis, high-pressure nervous system, gas toxicity, and thermal limitations. Work task requirements include drilling support, construction, inspection, and repair. Work systems include hyperbaric diving, atmospheric work systems, tele-operated work systems, and hybrid systems. Each type of work system is outlined in terms of work capabilities, special interface requirements, and limitations. Various operational philosophies are discussed. The evolution of work systems in the subsea industry has been the result of direct operational experience in a competitive market

In Vivo Healing of Meniscal Lacerations Using Bone Marrow-Derived Mesenchymal Stem Cells and Fibrin Glue

Fibrin glue created from a patient's own blood can be used as a carrier to deliver cells to the specific site of an injury. An experimental model for optimizing various permutations of this delivery system in vivo was tested in this study. Harvested equine meniscal sections were reapposed with fibrin glue or fibrin glue and equine bone marrow-derived mesenchymal stem cells (BMSCs). These constructs were then implanted subcutaneously in nude mice. After harvesting of the constructs, BMSC containing constructs showed significantly increased vascularization, and histology showed subjectively decreased thickness of repair tissue and increased total bonding compared to fibrin alone constructs. This model allowed direct comparison of different meniscal treatment groups while using a small number of animals. This in vivo model could be valuable in the future to optimize fibrin and cellular treatments for meniscal lesions in the horse and potentially humans as well

Fine Scale Influence of Weather on Northern Bobwhite Abundance, Breeding Success, and Harvest in South Texas

Weather plays a substantial role in annual changes in populations of northern bobwhite (Colinus virginianus) within and among ecological regions. Few studies have tested this relationship within the confines of specific sites. We examined the fine scale influence of annual (12-month), seasonal (6-month), and monthly Modified Palmer Drought Severity Indices (PMDI) and raw precipitation on abundance, breeding success, and harvest of northern bobwhites on 2 sites in south Texas. We used 18 years (1984–01) of roadside census, juvenile : adult ratios, and harvest records from the Chaparral Wildlife Management Area (CWMA) in La Salle County and 15 years (1984–99) of juvenile : adult ratios and harvest records from a private property in Brooks County (BCP) to examine relationships and trends with weather variables. Bobwhite abundance was correlated (r \u3e= 0.50, P \u3c= 0.035) with 12- and 6-month sums of precipitation and PMDI. Breeding success was correlated (r \u3e= 0.53, P \u3c= 0.023) with 12-month precipitation for both sites and was correlated (r = 0.53, P = 0.040) with 6-month precipitation for BCP only. Harvest variables for CWMA were correlated (r \u3e= 0.54, P \u3c= 0.022) with 12- and 6-month PMDI, while BCP harvest/ha was correlated (r = 0.54, P = 0.027) with the 12-month precipitation sum. Monthly correlates with precipitation increased from spring to summer until July when they became negatively related to rainfall on both sites. Monthly PMDI correlates became increasingly important from spring through summer including July. Our findings account for at least part of the annual variation in northern bobwhite abundance in south Texas and provide information useful in understanding of the influence of weather at fine spatial scales

Electrolyte gate-controlled Kondo effect in SrTiO3

We report low-temperature, high-field magnetotransport measurements of SrTiO3 gated by an ionic gel electrolyte. A saturating resistance upturn and negative magnetoresistance that signal the emergence of the Kondo effect appear for higher applied gate voltages. This observation, enabled by the wide tunability of the ionic gel-applied electric field, promotes the interpretation of the electric field-effect induced 2D electron system in SrTiO3 as an admixture of magnetic Ti3+ ions, i.e. localized and unpaired electrons, and delocalized electrons that partially fill the Ti 3d conduction band.Comment: Minor changes and Supp Info adde

Basic Communication Course Students’ Perceptions of the Purpose and Their Role in the Peer Feedback Process

Students enrolled in the basic communication course often engage in peer feedback workshops to enhance presentational speaking competence. As such, peer feedback workshops in the basic communication course provide an opportunity for students to provide and receive feedback on speech form, structure, and delivery (Broeckelman-Post & Hosek, 2014). The present study qualitatively examined data from 110 students enrolled in a basic communication course to determine their perceptions of the peer feedback process and what role(s), if any, they believed they had in the peer feedback process. Our thematic analysis revealed that students’ perceive peer feedback as a form of agency, influence, and skill building and perceive their role as a content editor, audience/body, and performance evaluator. Limitations and future research directions are also discussed

Temperature dependent c-axis hole mobilities in rubrene single crystals determined by time-of-flight

Hole mobilities (μ) in rubrene single crystals (space group Cmca) along the crystallographic c-axis have been investigated as a function of temperature and applied electric field by the time-of-fight method. Measurements demonstrate an inverse power law dependence on temperature, namely,μ=μ0T−n with n = 1.8, from room temperature down to 180 K. At 296 K, the average value of μ was found to be 0.29 cm2/Vs increasing to an average value of 0.70 cm2/Vs at 180 K. Below 180 K a decrease in mobility is observed with further cooling. Overall, these results confirm the anisotropic nature of transport in rubrene crystals as well as the generality of the inverse power law temperature dependence that is observed for field effect mobility measurements in the a-b crystal plane

Transcriptional profiling differences for articular cartilage and repair tissue in equine joint surface lesions

BACKGROUND: Full-thickness articular cartilage lesions that reach to the subchondral bone yet are restricted to the chondral compartment usually fill with a fibrocartilage-like repair tissue which is structurally and biomechanically compromised relative to normal articular cartilage. The objective of this study was to evaluate transcriptional differences between chondrocytes of normal articular cartilage and repair tissue cells four months post-microfracture. METHODS: Bilateral one-cm2 full-thickness defects were made in the articular surface of both distal femurs of four adult horses followed by subchondral microfracture. Four months postoperatively, repair tissue from the lesion site and grossly normal articular cartilage from within the same femorotibial joint were collected. Total RNA was isolated from the tissue samples, linearly amplified, and applied to a 9,413-probe set equine-specific cDNA microarray. Eight paired comparisons matched by limb and horse were made with a dye-swap experimental design with validation by histological analyses and quantitative real-time polymerase chain reaction (RT-qPCR). RESULTS: Statistical analyses revealed 3,327 (35.3%) differentially expressed probe sets. Expression of biomarkers typically associated with normal articular cartilage and fibrocartilage repair tissue corroborate earlier studies. Other changes in gene expression previously unassociated with cartilage repair were also revealed and validated by RT-qPCR. CONCLUSION: The magnitude of divergence in transcriptional profiles between normal chondrocytes and the cells that populate repair tissue reveal substantial functional differences between these two cell populations. At the four-month postoperative time point, the relative deficiency within repair tissue of gene transcripts which typically define articular cartilage indicate that while cells occupying the lesion might be of mesenchymal origin, they have not recapitulated differentiation to the chondrogenic phenotype of normal articular chondrocytes

Cartilage repair using hydrogels: a critical review of in vivo experimental designs

Prova tipográfica This review analyzes the outcomes and technical aspects of in vivo studies published in the past decade using gels and hydrogels for cartilage repair. Using PubMed search engine, original research publications during the period of 2002/01/01 to 2015/04/30 identifi ed 115 published papers. Of these, 3 studies failed to fi nd a statistically significant improvement of treatment group as compared to control and 18 studies did not clearly identify hyaline-like cartilage formation in the treated groups. The most frequent repaired lesion was the rabbit acute full thickness trochlear defect, using a scaff old combining a gel or hydrogel and other material. One third of the scaff olds were cell-free (35%) and the majority of the studies did not use growth factors (71%). The present review may constitute a useful tool in design of future studies, as limitations of study designs are pointed and results in terms of translation to human application is discussed.ARTICULATE project 623 (QREN-13/SI/2011-23189

Effect of self-assembling peptide, chondrogenic factors, and bone marrow-derived stromal cells on osteochondral repair

Objective The goal of this study was to test the ability of an injectable self-assembling peptide (KLD) hydrogel with or without chondrogenic factors (CF) and allogeneic bone marrow stromal cells (BMSCs) to stimulate cartilage regeneration in a full-thickness, critically-sized, rabbit cartilage defect model in vivo. We used CF treatments to test the hypotheses that CF would stimulate chondrogenesis and matrix production by cells migrating into acellular KLD (KLD + CF) or by BMSCs delivered in KLD (KLD + CF + BMSCs). Design Three groups were tested against contralateral untreated controls: KLD, KLD + CF, and KLD + CF +BMSCs, n = 6–7. Transforming growth factor-β1 (TGF-β1), dexamethasone, and insulin-like growth factor-1 (IGF-1) were used as CF pre-mixed with KLD and BMSCs before injection. Evaluations included gross, histological, immunohistochemical and radiographic analyses. Results KLD without CF or BMSCs showed the greatest repair after 12 weeks with significantly higher Safranin-O, collagen II immunostaining, and cumulative histology scores than untreated contralateral controls. KLD + CF resulted in significantly higher aggrecan immunostaining than untreated contralateral controls. Including allogeneic BMSCs + CF markedly reduced the quality of repair and increased osteophyte formation compared to KLD-alone. Conclusions These data show that KLD can fill full-thickness osteochondral defects in situ and improve cartilage repair as shown by Safranin-O, collagen II immunostaining, and cumulative histology. In this small animal model, the full-thickness critically-sized defect provided access to the marrow, similar in concept to abrasion arthroplasty or spongialization in large animal models, and suggests that combining KLD with these techniques may improve current practice.National Institutes of Health (U.S.) (National Institute for Biomedical Imaging and Bioengineering (U.S.) Grant EB003805)American Society for Engineering Education. National Defense Science and Engineering Graduate FellowshipNational Science Foundation (U.S.). Graduate Research FellowshipNational Institutes of Health (U.S.) (Grant EB003805)National Institutes of Health (U.S.) (Grant AR33236)Arthritis Foundation (Postdoctoral Fellowship