Calcium Phosphate/Clay Nanotube Bone Cement with Enhanced Mechanical Properties and Sustained Drug Release

Calcium phosphate cement (CPC) has limited use in bone repair due to their poor mechanical properties. Halloysite nanotubes (HNTs) are clay tubes with an aluminosilicate composition. The physicochemical properties, cytocompatibility, and cellular response to the CPC/HNT composites were assayed. Compression strength, FTIR analysis, protein synthesis, and mineralization were assessed. The cumulative data show that composites of tricalcium phosphate (TCP), anhydrous calcium diphosphate (DCPA) as the solid phase agent, and 10% chitosan lactate solution as the setting liquid produced cement with sustained release properties without loss of material strength. The composite also showed enhanced material properties (adhesiveness, surface roughness, and increased strength). Cellular assays confirm its osteoconductive and osteoinductive nature. CPCs, loaded with gentamicin- and neomycin-doped HNTs, showed sustained antibacterial release and marked zone of growth inhibition. CPCs fabricated with drug-doped HNTs offer a means for inducing bone growth at the site of implantation while controlling infection. This treatment modality should hasten patient healing time and enhance restoration of function. The increase in materials properties suggests that this CPC may be clinically applied to repair injuries in load-bearing bones

Advancing time- and angle-resolved photoemission spectroscopy: The role of ultrafast laser development

In the last decade, there has been a proliferation of laser sources for time- and angle-resolved photoemission spectroscopy (TR-ARPES), building on the proven capability of this technique to tackle important scientific questions. In this review, we aim to identify the key motivations and technologies that spurred the development of various laser sources, from frequency up-conversion in nonlinear crystals to high-harmonic generation in gases. We begin with a historical overview of the field in Sec.1, framed by advancements in light source and electron spectrometer technology. An introduction to the fundamental aspects of the photoemission process and the observables that can be studied is given in Sec.2, along with its dependencies on the pump and probe pulse parameters. The technical aspects of TR-ARPES are discussed in Sec.3. Here, experimental limitations such as space charge and resultant trade-offs in source parameters are discussed. Details of various systems and their approach to these trade-offs are given in Sec.4. Within this discussion, we present a survey of TR-ARPES laser sources; a meta-analysis of these source parameters showcases the advancements and trends in modern systems. Lastly, we conclude with a brief discussion of future directions for TR-ARPES and its capabilities in elucidating equilibrium and non-equilibrium observables, as well as its integration with micro-ARPES and spin-resolved ARPES (Sec.5).Comment: 104 pages, 27 figure

The Strontium-Coated Clay Nanoparticles in Calcium Phosphate Cement for Biomedical Applications

Anusha Elumalai, Yangyang Luo, and Ahmed Humayun are graduate students in Molecular Science and Nanotechnology at Louisiana Tech University. Dr. David K. Mills is a professor in the School of Biological Sciences at Louisiana Tech University. The abstract for The Strontium-Coated Clay Nanoparticles in Calcium Phosphate Cement for Biomedical Applications can be downloaded by clicking on the blue download button

Osteoblast Behavior on Silicon and Porous-Silicon Substrates

Osteoblast viability, proliferation, protein expression and mineralization were studied on bare, micro- and nanoporous silicon (Si) substrates. Micro- and nano-porous-Si substrates were prepared by anodic etching of silicon in ethanolic hydrofluoric acid and characterized using scanning electron and atomic force microscopies. Mouse osteoblasts were cultured on these substrates and cellular response to these surfaces was assessed using the Live/Dead Cell Viability assay and the MTT assay for cell proliferation. Osteoblast functionality was assessed using immunohistochemistry for bone protein specific markers. Osteoblasts grew well on micro- and nanoporous silicon substrates over the twenty-one day experimental period supporting the assessment that these are suitable cell supportive surfaces. Cell proliferation rates on bare and nanoporous silicon were similar initially, however, nanoporous silicon displayed enhanced cell proliferation, in comparison to bare silicon, after 14 days in culture. Immunocytochemical assays, using bone specific markers, showed positive reactions for osteonectin and osteopontin expression on all substrates with staining intensity increasing over the 21-day experimental period. Calcium mineral deposits were quantified using the Alizarin Red histochemical assay and nanoporous silicon induced the highest level of calcium mineral production in comparison to bare and microporous silicon. The data supports the potential use of nanoporous silicon as a surface implant coating for dental and orthopedic applications. The ability to dope (and then release) drugs or growth factors from the silicon nanopores offers the potential for a multi-functional implant surface

Detailed observations of the phytoplankton spring bloom in the stratifying central North Sea

Analysis of detailed time series of bio-optical and temperature data from the North Sea supports the view that a minimum level of turbulence is a prerequisite for the onset and maintenance of the phytoplankton spring bloom in shelf seas, which distinguishes these seas from the open ocean. The start of the spring bloom, primarily diatoms, is controlled by the light regime, while its progress is predominantly dependent upon episodic turbulence input following short periods of stratification, which allow the resuspension of a fast sinking (50-200 m day-1) phytoplankton community from the bottom mixing layer. A relationship between turbulence and the vertical distribution of phytoplankton is proposed which is found at synoptic time scales and on time scales of a day and less. Throughout the spring bloom, algal biomass is either equally distributed through the water column or concentrated in the bottom mixing layer. Growth can only be sustained in the near-surface layer during periods of substantial turbulence input. The establishment of semi-permanent seasonal stratification causes an almost complete reduction in near-surface biomass and a concomitant increase in biomass in the bottom mixing layer which subsequently acts as a source for occasional increased near-surface biomass until early summer

Loss of murine Paneth cell function alters the immature intestinal microbiome and mimics changes seen in neonatal necrotizing enterocolitis

Necrotizing enterocolitis (NEC) remains the leading cause of gastrointestinal morbidity and mortality in premature infants. Human and animal studies suggest a role for Paneth cells in NEC pathogenesis. Paneth cells play critical roles in host-microbial interactions and epithelial homeostasis. The ramifications of eliminating Paneth cell function on the immature host-microbial axis remains incomplete. Paneth cell function was depleted in the immature murine intestine using chemical and genetic models, which resulted in intestinal injury consistent with NEC. Paneth cell depletion was confirmed using histology, electron microscopy, flow cytometry, and real time RT-PCR. Cecal samples were analyzed at various time points to determine the effects of Paneth cell depletion with and without Klebsiella gavage on the microbiome. Deficient Paneth cell function induced significant compositional changes in the cecal microbiome with a significant increase in Enterobacteriacae species. Further, the bloom of Enterobacteriaceae species that occurs is phenotypically similar to what is seen in human NEC. This further strengthens our understanding of the importance of Paneth cells to intestinal homeostasis in the immature intestine

Making space for embedded knowledge in global mental health: a role for social work

The ‘Global Mental Health’ (GMH) movement, an influential driver of transnational knowledge transfer in the field of mental health, advocates evidence-based strategies to ‘scale up’ services in low- and middle-income countries. As with debates on global and local frameworks for social work, there are concerns about marginalisation of knowledge that does not neatly fit the GMH discourse. This article analyses the professional and disciplinary structures that shape knowledge transfer in GMH and the implications for social work's engagement with the movement. Analysis of key documents and secondary literature identifies three key issues for GMH: its potentially negative impact on ‘local’ knowledge production; the challenges of accounting for culture and context; and the selective forms of evidence that are ‘allowed’ to contribute to GMH. Finding ways to encompass more ‘situated’ perspectives could reshape GMH in accord with its aspirations for participation by a wider range of stakeholders. Social work's values-based commitment to rights and empowerment, emphasis on embedded knowledge emerging from close links with practice, and theoretical engagement with social, cultural and political context, enable the profession to contribute significantly to this task. Such engagement would bring improvements in care for those suffering from mental health disorders, their families and communities

Sports review: A content analysis of the International Review for the Sociology of Sport, the Journal of Sport and Social Issues and the Sociology of Sport Journal across 25 years

The International Review for the Sociology of Sport, the Journal of Sport and Social Issues and Sociology of Sport Journal have individually and collectively been subject to a systematic content analysis. By focusing on substantive research papers published in these three journals over a 25-year time period it is possible to identify the topics that have featured within the sociology of sport. The purpose of the study was to identify the dominant themes, sports, countries, methodological frameworks and theoretical perspectives that have appeared in the research papers published in these three journals. Using the terms, identified by the author(s), that appear in the paper’s title, abstract and/or listed as a key word, subject term or geographical term, a baseline is established to reflect on the development of the sub-discipline as represented by the content of these three journals. It is suggested that the findings illustrate what many of the more experienced practitioners in the field may have felt subjectively. On the basis of this systematic, empirical study it is now possible to identify those areas have received extensive coverage and those which are under-researched within the sociology of sport. The findings are used to inform a discussion of the role of academic journals and the recent contributions made by Michael Silk, David Andrews, Michael Atkinson and Dominic Malcolm on the past, present and future of the ‘sociology of sport’

Use of coping strategies in MND/ALS:association with demographic and disease-related characteristics

Objective Understanding the use of coping strategies and which factors are associated with strategy utilization might help clinical staff anticipate which coping strategies individuals are more likely to utilize. In this study, we assess coping strategy use in the motor neuron disease (MND, also known as amyotrophic lateral sclerosis [ALS]) population and examine associations of demographic and disease variables with individual coping strategies. Participants and Methods A total of 233 participants with MND/ALS were recruited into the ongoing Trajectories of Outcomes in Neurological Conditions study from MND clinics across the United Kingdom. Participants completed a questionnaire pack collecting data on demographics and a range of patient‐reported measures including the Coping Orientations to Problems Experienced scale. Associations between demographic and clinical characteristics and coping strategies were examined by simple and multiple ordinal logistic regression. Results The most commonly used strategy was Acceptance, followed by Active Coping, Planning and Positive Re‐interpretation and Growth. The least used strategies were Substance Use, Turning to Religion and Denial. Ten out of the fifteen strategies showed statistically significant associations with demographic and clinical characteristics. Most markedly, females were found to utilize many strategies more than males, namely Restraint, Seeking Instrumental Social Support, Seeking Emotional Social Support, Focus on and Venting of Emotions, Behavioural Disengagement and Mental Disengagement. Conclusion Clinical staff should be aware that coping strategy use is associated with several demographic and disease characteristics. Targeted advice on coping may improve coping capacity and facilitate psychosocial adjustment