Stabilization of colloidal palladium particles by a block copolymer of polystyrene and a block containing amide sidegroups

A block copolymer of polystyrene and poly(tert-butylmethacrylate) was prepared by anionic polymerization. The ester groups of the poly(tert-butylmethacrylate) were hydrolyzed, after wich the remaining carboxyl groups were reacted with pyrrolidine. The resulting block copolymer with amide sidegroups was used for stabilization of a palladium colloid in toluene

Why Post That? Re-thinking the Problem of Absent Presence within Social Media

While social media have the potential to promote positive relations online, the increasing use of contemporary apps, such as Instagram, distances many from important face-to-face interactions. In this study, we rethink the problem of ‘absentpresence’ within social media by revealing the language games of Instagram. Drawing on social media literature and Gergen’s (2002) concern about the erosion of cultural norms due to the absent presence generated by new media, we engaged in a qualitative study of active Instagram users. Employing a unique ‘prompt and response’ interview approach, in which we asked participants to explain why they would (or would not) post particular statements, we gain insights into social norms of Instagram as expressed by active social media users. The results of this study show that participants base their posting decisions largely on their perception of a desired self, without much concern for who is posting or why they are posting. Because our findings reveal that posting on Instagram is done without much engagement with others and is often done only if a message corresponds with their own experiences or self-identification, this study extends the concern about absent presence. Specifically, we argue that the complex blurring of monologic and dialogic forms of communication found in contemporary social media apps generates hollow and inconsequential language games that maintain narrow concepts of self and fail to generate interactions necessary to co-create relevant and meaningful socialvalues

The era of bioengineering: how will this affect the next generation of cancer immunotherapy?

Immunotherapy consists of activating the patient's immune system to fight cancer and has the great potential of preventing future relapses thanks to immunological memory. A great variety of strategies have emerged to harness the immune system against tumors, from the administration of immunomodulatory agents that activate immune cells, to therapeutic vaccines or infusion of previously activated cancer-specific T cells. However, despite great recent progress many difficulties still remain, which prevent the widespread use of immunotherapy. Some of these limitations include: systemic toxicity, weak immune cellular responses or persistence over time and most ultimately costly and time-consuming procedures. Synthetic and natural biomaterials hold great potential to address these hurdles providing biocompatible systems capable of targeted local delivery, co-delivery, and controlled and/or sustained release. In this review we discuss some of the bioengineered solutions and approaches developed so far and how biomaterials can be further implemented to help and shape the future of cancer immunotherapy. The bioengineering strategies here presented constitute a powerful toolkit to develop safe and successful novel cancer immunotherapies

Ischaemic heart disease in Turkish migrants with type 2 diabetes mellitus in The Netherlands: wait for the next generation?

OBJECTIVE: To study the prevalence of ischaemic heart disease in Turkish and Surinam-Asian migrants with type 2 diabetes mellitus in the Netherlands as compared with Europeans. METHODS: In a consecutive case-control study, 59 Turkish and 62 Surinam-Asian patients were compared with 185 Europeans referred to a diabetes clinic for treatment of type 2 diabetes in the period 1992 to 1998. Main outcome measures were ischaemic heart disease and its associated risk factors. RESULTS: The prevalence of ischaemic heart disease was lower (9%) in the Turks (p < 0.02), but higher (29%) in the Surinam-Asians compared with the Europeans (23%). The Turks (52 +/- 10 years) and Surinam-Asians (46 +/- 12 years) were younger than the Europeans (64 +/- 11 years, p < 0.001). Body mass index was 32 +/- 5 (p < 0.001) in the Turks, 27 +/- 5 in the Surinam-Asians (p < 0.05) and 29 +/- 5 in the Europeans. Turkish patients smoked less (23%, p < 0.05) and used less alcohol (4%, p < 0.05) than the Europeans. Proteinuria was found in 24% of the Turks (p < 0.05), 37% of the Surinam-Asians (NS) and 46% of the Europeans. In univariate analysis ischaemic heart disease was related to Turkish origin, OR 0.34 (0.14-0.83) p < 0.02, to Surinam-Asian origin, OR 1.84 (1.00-3.38) p = 0.05, and smoking, OR 1.78 (1.18-2.68) p < 0.01. Other variables were not related to ischaemic heart disease. Multivariate analysis in a model with ethnicity and smoking showed significant relations between ischaemic heart disease and Turkish ethnicity, OR 0.19 (0.06-0.65) p = 0.007, Surinam-Asian origin, OR 2.77 (1.45-5.28) p = 0.002, and smoking, OR 1.79 (1.20-2.66) p = 0.004. CONCLUSION: Type 2 diabetes mellitus in different ethnic groups results in a significant difference in incidence of ischaemic heart disease. The most remarkable finding is a low incidence of ischaemic heart disease in the Turkish patients with type 2 diabetes, independent of smoking. The high prevalence of ischaemic heart disease in young migrant Asians with diabetes is confirmed

Ruimtelijke dynamiek van weidevogelpopulaties in relatie tot de kwaliteit van de broedhabitat. Welke factoren beïnvloeden de vestiging van weidevogels?

Recent onderzoek toonde aan dat percelen met een uitgestelde maaidatum geen hogere dichtheden weidevogels herbergen dan gangbaar, vroeg gemaaide percelen. Deze resultaten zijn moeilijk te verklaren aan de hand van bestaande kennis over ruimtelijke dynamiek en nestplaatskeuze van weidevogels. Deze studie heeft tot doel vast te stellen of de nestplaatsen van weidevogels ruimtelijke geassocieerd zijn met één of meerdere omgevingsvariabelen in de vestigingsfase. Voor de grutto werd daarnaast nog gekeken of de aanleg van plas-dras percelen leidt tot een verhoging van het aantal broedparen in de nabijheid van deze percelen en wat de invloedssfeer is van deze percelen (waar broeden de grutto’s die gebruik maken van een plas-dras perceel?)

Potential novel drug carriers for inner ear treatment: hyperbranched polylysine and lipid nanocapsules

AIM: Treatment of sensorineural hearing loss could be advanced using novel drug carriers such as hyperbranched polylysine (HBPL) or lipid nanocapsules (LNCs). This study examined HBPL and LNCs for their cellular uptake and possible toxicity in vitro and in vivo as the first step in developing novel nanosized multifunctional carriers. METHOD: Having incubated HBPL and LNCs with fibroblasts, nanoparticle uptake and cell viability were determined by confocal laser scanning microscopy, fluorescence measurements and neutral red staining. In vivo, electrophysiology, confocal laser scanning microscopy and cytocochleograms were performed for nanoparticle detection and also toxicity studies after intracochlear application. RESULTS: Both nanoparticles were detectable in the fibroblasts\u27 cytoplasm without causing cytotoxic effects. After in vivo application they were visualized in cochlear cells, which did not lead to a change in hearing threshold or loss of hair cells. Biocompatibility and traceability were demonstrated for HBPL and LNCs. Thus, they comply with the basic requirements for drug carriers for potential application in the inner ear

Influence of block versus random monomer distribution on the cellular uptake of hydrophilic copolymers

The use of polymers has revolutionized the field of drug delivery in the past two decades. Properties such as polymer size, charge, hydrophilicity, or branching have all been shown to play an important role in the cellular internalization of polymeric systems. In contrast, the fundamental impact of monomer distribution on the resulting biological properties of copolymers remains poorly studied and is always only investigated for biologically active self-assembling polymeric systems. Here, we explore the fundamental influence of monomer distribution on the cellular uptake of nonaggregating and biologically passive copolymers. Reversible addition–fragmentation chain-transfer (RAFT) polymerization was used to prepare precisely defined copolymers of three hydrophilic acrylamide monomers. The cellular internalization of block copolymers was compared with the uptake of a random copolymer where monomers are statistically distributed along the chain. The results demonstrate that monomer distribution in itself has a negligible impact on copolymer uptake