233 research outputs found

    New molecular architectures based on dendrimers

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    Artificial cells: synthetic compartments with life-like functionality and adaptivity

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    Cells are highly advanced microreactors that form the basis of all life. Their fascinating complexity has inspired scientists to create analogs from synthetic and natural components using a bottom-up approach. The ultimate goal here is to assemble a fully man-made cell that displays functionality and adaptivity as advanced as that found in nature, which will not only provide insight into the fundamental processes in natural cells but also pave the way for new applications of such artificial cells.In this Account, we highlight our recent work and that of others on the construction of artificial cells. First, we will introduce the key features that characterize a living system; next, we will discuss how these have been imitated in artificial cells. First, compartmentalization is crucial to separate the inner chemical milieu from the external environment. Current state-of-the-art artificial cells comprise subcompartments to mimic the hierarchical architecture of eukaryotic cells and tissue. Furthermore, synthetic gene circuits have been used to encode genetic information that creates complex behavior like pulses or feedback. Additionally, artificial cells have to reproduce to maintain a population. Controlled growth and fission of synthetic compartments have been demonstrated, but the extensive regulation of cell division in nature is still unmatched.Here, we also point out important challenges the field needs to overcome to realize its full potential. As artificial cells integrate increasing orders of functionality, maintaining a supporting metabolism that can regenerate key metabolites becomes crucial. Furthermore, life does not operate in isolation. Natural cells constantly sense their environment, exchange (chemical) signals, and can move toward a chemoattractant. Here, we specifically explore recent efforts to reproduce such adaptivity in artificial cells. For instance, synthetic compartments have been produced that can recruit proteins to the membrane upon an external stimulus or modulate their membrane composition and permeability to control their interaction with the environment. A next step would be the communication of artificial cells with either bacteria or another artificial cell. Indeed, examples of such primitive chemical signaling are presented. Finally, motility is important for many organisms and has, therefore, also been pursued in synthetic systems. Synthetic compartments that were designed to move in a directed, controlled manner have been assembled, and directed movement toward a chemical attractant is among one of the most life-like directions currently under research.Although the bottom-up construction of an artificial cell that can be truly considered “alive” is still an ambitious goal, the recent work discussed in this Account shows that this is an active field with contributions from diverse disciplines like materials chemistry and biochemistry. Notably, research during the past decade has already provided valuable insights into complex synthetic systems with life-like properties. In the future, artificial cells are thought to contribute to an increased understanding of processes in natural cells and provide opportunities to create smart, autonomous, cell-like materials.<br/

    Feminism in Flux : Indigenous Rights Activism and the Evolution of Feminism in New South Wales, 1930-1960

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    From the 1930s in Australia, white female voices of protest regarding Indigenous affairs were prominent. While undoubtedly emerging from philanthropic concerns, this thesis argues that more can be elicited from white women’s interest in Indigenous affairs. My focus is feminist organisations in Sydney between 1930 and 1960 where Indigenous affairs were continually a part of a ‘progressive’ feminist agenda which in the period shifted to the left of the political spectrum. A feminist interest in Indigenous rights is used to illustrate the radicalisation of feminism from the conservatism of the 1930s to the antecedents of the politics of female liberation in the 1950s

    Social and Psychological Adjustments of First Generation Polish Immigrants to Australia

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    The primary aim of this research was to find predictors of psycho-social adjustment of Polish immigrants to Sydney, Australia. There were two sets of independent variables considered: i) personal characteristics, including: intelligence, extraversion, neuroticism, style of attribution and self-acceptance and ii) demographic information, consisted of: age, gender, length of residence, marital status, number of children, educational level, yearly income, immigration status (dependent vs. independent immigration) and residential status. The dependent variables were social (adaptation and assimilation) and psychological adjustment. The hypotheses tested in the study were that each of these personal and demographic characteristics would be associated with adaptation and/or assimilation, and psychological well-being. The two samples (both studies) were composed of more than 200 first generation Polish immigrants who arrived in Australia after 1980. No significant gender differences were found. The internal consistency and principal components structure of Adaptation and Assimilation were examined, and the measures were refined. There were employed standard measurements (i.e. GHQ, BDI, BAI, EPI, ASQ, Raven Matrices and WAIS-Vocabulary) and newly developed measures (i.e. the Social Adjustment Scale and the Self-Acceptance Questionnaire). The general results suggested that psycho-social adjustment was best predicted by three pre-arrival characteristics (extraversion, education and self-acceptance), and post-arrival employment status and length of residence. There were, however, some differences in regard to the particular aspects of psycho-social adjustment. Better adaptation was meaningfully related to employment (income) and education in Study 1, and self-acceptance, employment and extraversion in Study 2; better assimilation seemed to be significantly predicted by education, age of arrival and length of residence (Study 1), and self-acceptance, extraversion, education and age of arrival (Study 2). Psychological [mal]adjustment was best indicated by globality and stability in attributing negative events (Study 1), lower self-acceptance and lack of employment status (Study 2)

    Bio-inks for 3D bioprinting:recent advances and future prospects

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    In the last decade, interest in the field of three-dimensional (3D) bioprinting has increased enormously. 3D bioprinting combines the fields of developmental biology, stem cells, and computer and materials science to create complex bio-hybrid structures for various applications. It is able to precisely place different cell types, biomaterials and biomolecules together in a predefined position to generate printed composite architectures. In the field of tissue engineering, 3D bioprinting has allowed the study of tissues and organs on a new level. In clinical applications, new models have been generated to study disease pathogenesis. One of the most important components of 3D bio-printing is the bio-ink, which is a mixture of cells, biomaterials and bioactive molecules that creates the printed article. This review describes all the currently used bio-printing inks, including polymeric hydrogels, polymer bead microcarriers, cell aggregates and extracellular matrix proteins. Amongst the polymeric components in bio-inks are: natural polymers including gelatin, hyaluronic acid, silk proteins and elastin; and synthetic polymers including amphiphilic block copolymers, PEG, poly(PNIPAAM) and polyphosphazenes. Furthermore, photocrosslinkable and thermoresponsive materials are described. To provide readers with an understanding of the context, the review also contains an overview of current bio-printing techniques and finishes with a summary of bio-printing applications.</p

    Child care support programs for double income families in Korea

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    Kriteria Visibilitas Hilal Rukyatul Hilal Indonesia (Rhi) (Konsep, Kriteria, dan Implementasi)

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    Telah dilaksanakan observasi hilal dan hilal tua selama periode Zulhijjah 1427–Zulhijjah 1430 H (Januari 2007–Desember 2009) oleh jejaring titik observasi Rukyatul Hilal Indonesia (RHI) yang merentang dari lintang 5° LU hingga 31° LS, dengan ataupun tanpa bantuan alat bantu optik. Observasi menghasilkan 174 data visibilitas yang terdiri dari 107 visibilitas positif dan 67 visibilitas negatif. Analisis korelasi linier Lag dengan Best Time Bulan menghasilkan definisi baru tentang hilal, yaitu Bulan pasca konjungsi yang memiliki Lag ≤ 24 menit hingga Lag ≤ 40 menit saat Matahari terbenam. Hubungan Best Time dan Lag memenuhi persamaan linear Yallop hanya untuk Lag ≤ 40 menit. Analisis korelasi aD dan DAz dengan metode least–square menghasilkan persamaan kriteria RHI aD ≥ 0,099 DAz2–1,490 DAz + 10,382 yang bentuknya hampir sama dengan kriteria LAPAN, namun sangat berbeda dibanding kriteria Fotheringham–Maunder maupun Bruin. Analisa komparatif menyimpulkan asumsi yang dipergunakan “kriteria” Imkanur Rukyat versi MABIMS dan konsep wujudul hilal tidak terbukti. Sebaliknya, terdapat kesesuaian antara hasil observasi dengan kriteria Odeh

    On shifting ground

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    This research paper explores some of the transition/tension between the past and the present (old and the new) in the current socio/political transformation. Through the trajectory of my own Norwegian background, I will investigate the use of heritage and ‘soft’ nationalism within formation of national identity, and look at some artists’ response to the current political discourse, through both their art making or writing. By investigating two distinctive symbols of national heritage, the bunad and Borre National Park, I hope to shine light on the complicated balancing act of the dichotomy between inclusion and exclusion when embracing national identity through a common history. The bunad is an increasingly popular, semi-invented national costume, and Borre is the largest burial site from the Viking era in Scandinavia. Furthermore, I will also explore social anthropological thinking around Eric Hobsnawn’s concept of ‘the invention of tradition’. The paper will look at the significance of the landscape and geographical identity, as well as the symbioses between place and the concept of the nation state. Inserted into this, I will discuss some of the outcomes from the intense changeover from analogue technologies to the digital—generating new practices working across the mediums of photography, film/video and the digital. The hybrid medium specificity of the still-motion is of particular interest to my art practice. This video-formatted offspring of the slideshow allows for an expansion of the photographic medium, by viewing it through a cinematic frame, and in the process generating new narrative opportunities and registration of time. Finally, all the concerns articulated in this research will inform my final artwork exhibited in the SCA Postgraduate Degree show in December 2014; a two-piece video installation entitled On Shifting Ground

    Алгоритм функціонування системи захисту

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    Детально розглянуті алгоритми виявлення атак у середовищі мереж зв'язку.In detail the algorithms of exposure of attacks are considered in the environment of communication network

    Socially-mediated changes in brain epigenome in the fire ant

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    Herein, we report a robust way for the formation of biodegradable poly(ethylene glycol)-block-poly(e-caprolactone) (PEG-b-PCL) polymersomes, via direct hydration of a highly concentrated block copolymer/oligo(ethylene glycol) solution. Polymersomes with variable membrane thickness were formed under relatively mild conditions in a short time, by changing the hydrophobic block length. Plunge freezing followed by cryo transmission electron microscopy (Cryo-TEM) was utilized to visualize the morphology of newly-formed polymersomes in their native condition. An MTT cytotoxicity study showed that the as-prepared polymersomes have good biocompatibility to hCMEC/D3 brain endothelial cells. As this method does not involve the use of small molecular organic solvent, sonication or freeze-thawing steps, it can offer the opportunity to form biodegradable polymersomes on-site. The work may facilitate the bench-to-bedside translation of biodegradable polymersomes as robust drug nanocarriers
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