Surface modification of ultra‐high‐molecular‐weight polyethylene. I. Characterization and sintering studies

We performed surface modification of ultra‐high‐molecular‐weight polyethylene (UHMWPE) through chromic acid etching with the aim of improving the performance of UHMWPE's composites with poly(ethylene terephthalate) fibers. In part I of this study, we evaluated the effects of chemical modification on the surface properties of UHMWPE with X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and contact angle measurements. The thermal properties, rheology, and sintering behavior of the modified UHMWPE were compared to those of the base material. XPS and FTIR analysis confirmed the presence of carboxyl and hydroxyl groups on the surface of the modified powders. The substitution of polar groups into the backbone of the polymer decreased its contact angles with water and hexadecane and increased its surface energy, as evidenced by contact angle measurements. The modified UHMWPE was more crystalline than the base resin and less prone to thermal degradation. Although the rheological properties were virtually identical, the modified powders sintered more readily, presumably due to their higher surface energy, which suggested enhanced processability by compression molding. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Towards children's creative museum engagement and collaborative sense-making

Abstract

In this article, we elucidate a socio-culturally framed approach to supporting children's creative museum engagement. Specifically, we focus on social activities and socio-cultural resources that can act as boundary-permeating objects in mediating children's creative engagement and collaborative sense-making regarding cultural content within, across and beyond the spatio-material context of the museum. We contend that designing and organising children's creative engagement and collaborative sense-making in ways that cultivate boundary-crossing broadens opportunities for engagement and leverages children's creative potential and expansive learning. We build our argument by starting with a theoretical introduction to the design principles that constitute the Kids, Museums, and Technology Programme. We will illuminate the design principles of the programme with empirical examples and consider how the design principles and their situated construction can help us re-imagine museum exhibitions as hybrid, boundary-permeating spaces that afford novel transformative interactions, as well as new roles and identities for both children and museums.     

HCI and Society: Towards a Typology of Universal Design Principles

The task of this article is to focus on aspects of design from a theoretical perspective that works out a general framework of techno-social design that is grounded in the notion of the participatory, cooperative, sustainable information society. The approach is normative in that it is based on the judgment that not just any information society is needed, but one that has specific qualities that this article tries to identify. Methodologically, the article works out a conceptual framework that synthesizes general social theory and human–computer interaction. Design is seen as a social process that shapes society and techno-social systems. First, a model of society that is based on the dialectical interaction of economic, political, and cultural subsystems is introduced. Then, the notion of the the participatory, cooperative, sustainable information society is introduced. This theoretical definition is then used for classifying design principles of techno-social information systems from a social theory perspective.     

On semidefinite programming bounds for graph bandwidth

In this paper, we propose two new lower bounds on graph bandwidth and cyclic bandwidth based on semidefinite programming (SDP) relaxations of the quadratic assignment problem. We compare the new bounds with two other SDP bounds reported in [A. Blum, G. Konjevod, R. Ravi, and S. Vempala, Semi-definite relaxations for minimum bandwidth and other vertex-ordering problems, Theoret. Comput. Sci. 235(1) (2000), pp. 25–42; J. Povh and F. Rendl, A copositive programming approach to graph partitioning, SIAM J. Optim. 18(1) (2007), pp. 223–241].     

Glycan-Lectin Interactions as Novel Immunosuppression Drivers in Glioblastoma

Despite diagnostic and therapeutic improvements, glioblastoma (GB) remains one of the most threatening brain tumor in adults, underlining the urgent need of new therapeutic targets. Lectins are glycan-binding proteins that regulate several biological processes through the recognition of specific sugar motifs. Lectins and their ligands are found on immune cells, endothelial cells and, also, tumor cells, pointing out a strong correlation among immunity, tumor microenvironment and vascularization. In GB, altered glycans and lectins contribute to tumor progression and immune evasion, shaping the tumor-immune landscape promoting immunosuppressive cell subsets, such as myeloid-derived suppressor cells (MDSCs) and M2-macrophages, and affecting immunoeffector populations, such as CD8⁺ T cells and dendritic cells (DCs). Here, we discuss the latest knowledge on the immune cells, immune related lectin receptors (C-type lectins, Siglecs, galectins) and changes in glycosylation that are involved in immunosuppressive mechanisms in GB, highlighting their interest as possible novel therapeutical targets.     

Hybrid Self-Assembling Nanoparticles Encapsulating Zoledronic Acid: A Strategy for Fostering Their Clinical Use

Self-assembling nanoparticles (SANPs) promise an effective delivery of bisphosphonates or microRNAs in the treatment of glioblastoma (GBM) and are obtained through the sequential mixing of four components immediately before use. The self-assembling approach facilitates technology transfer, but the complexity of the SANP preparation protocol raises significant concerns in the clinical setting due to the high risk of human errors during the procedure. In this work, it was hypothesized that the SANP preparation protocol could be simplified by using freeze-dried formulations. An in-depth thermodynamic study was conducted on solutions of different cryoprotectants, namely sucrose, mannitol and trehalose, to test their ability to stabilize the produced SANPs. In addition, the ability of SANPs to deliver drugs after lyophilization was assessed on selected formulations encapsulating zoledronic acid in vitro in the T98G GBM cell line and in vivo in an orthotopic mouse model. Results showed that, after lyophilization optimization, freeze-dried SANPs encapsulating zoledronic acid could retain their delivery ability, showing a significant inhibition of T98G cell growth both in vitro and in vivo. Overall, these results suggest that freeze-drying may help boost the industrial development of SANPs for the delivery of drugs to the brain.     

Network Analysis of Gut Microbiome and Metabolome to Discover Microbiota-Linked Biomarkers in Patients Affected by Non-Small Cell Lung Cancer

Several studies in recent times have linked gut microbiome (GM) diversity to the pathogenesis of cancer and its role in disease progression through immune response, inflammation and metabolism modulation. This study focused on the use of network analysis and weighted gene co-expression network analysis (WGCNA) to identify the biological interaction between the gut ecosystem and its metabolites that could impact the immunotherapy response in non-small cell lung cancer (NSCLC) patients undergoing second-line treatment with anti-PD1. Metabolomic data were merged with operational taxonomic units (OTUs) from 16S RNA-targeted metagenomics and classified by chemometric models. The traits considered for the analyses were: (i) condition: disease or control (CTRLs), and (ii) treatment: responder (R) or non-responder (NR). Network analysis indicated that indole and its derivatives, aldehydes and alcohols could play a signaling role in GM functionality. WGCNA generated, instead, strong correlations between short-chain fatty acids (SCFAs) and a healthy GM. Furthermore, commensal bacteria such as Akkermansia muciniphila, Rikenellaceae, Bacteroides, Peptostreptococcaceae, Mogibacteriaceae and Clostridiaceae were found to be more abundant in CTRLs than in NSCLC patients. Our preliminary study demonstrates that the discovery of microbiota-linked biomarkers could provide an indication on the road towards personalized management of NSCLC patients.