846 research outputs found

    Design Principles for Aqueous Interactive Materials: Lessons from Small Molecules and Stimuli-Responsive Systems.

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    Interactive materials are at the forefront of current materials research with few examples in the literature. Researchers are inspired by nature to develop materials that can modulate and adapt their behavior in accordance with their surroundings. Stimuli-responsive systems have been developed over the past decades which, although often described as "smart," lack the ability to act autonomously. Nevertheless, these systems attract attention on account of the resultant materials' ability to change their properties in a predicable manner. These materials find application in a plethora of areas including drug delivery, artificial muscles, etc. Stimuli-responsive materials are serving as the precursors for next-generation interactive materials. Interest in these systems has resulted in a library of well-developed chemical motifs; however, there is a fundamental gap between stimuli-responsive and interactive materials. In this perspective, current state-of-the-art stimuli-responsive materials are outlined with a specific emphasis on aqueous macroscopic interactive materials. Compartmentalization, critical for achieving interactivity, relies on hydrophobic, hydrophilic, supramolecular, and ionic interactions, which are commonly present in aqueous systems and enable complex self-assembly processes. Relevant examples of aqueous interactive materials that do exist are given, and design principles to realize the next generation of materials with embedded autonomous function are suggested.JAM thanks ESPRC for an IAA KTF M is grateful for a Newton International Fellowship OAS is thankful to ERC Consolidator Grant CAM-RI

    The environment effect on operation of in-vessel mirrors for plasma diagnostics in fusion devices

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    First mirrors will be the plasma facing components of optical diagnostic systems in ITER. Mirror surfaces will undergo modification caused by erosion and re-deposition processes [1,2]. As a consequence, the mirror performance may be changed and may deteriorate [3,4]. In the divertor region it may also be obscured by deposition [5-7]. The limited access to in-vessel components of ITER calls for testing the mirror materials in present day devices in order to gather information on the material damage and degradation of the mirror performance, i.e. reflectivity. A dedicated experimental programme, First Mirror Test (FMT), has been initiated at the JET tokamak within the framework Tritium Retention Studies (TRS).Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France).Submitted by B. Schunke on behalf of V. Voytseny

    FASIES FORMASI LEMAT DAERAH BELALANGAN DAN SEKITARNYA, KECAMATAN BATANG ASAM, KABUPATEN TANJUNG JABUNG BARAT, PROVINSI JAMBI

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    Secara geografis daerah penelitian terletak pada koordinat (UTM – WGS84 zona 48S) 269400-272500 mT dan 9868800-9872000 mU. Sedangkan secara administratif daerah penelitian masuk ke dalam wilayah Kecamatan Batang Asam, Kabupaten Tanjung Jabung Barat, Provinsi Jambi. Satuan bentuk lahan daerah penelitian, antara lain Satuan Bentuk Lahan Perbukitan Bergelombang BerlerengSedang (S1), Satuan Bentuk Lahan Perbukitan Sesar Bergelombang (S2), Satuan Bentuk Lahan Perbukitan Homoklin Berlereng Miring (S3) dan Satuan Bentuk Lahan Tubuh Sungai (F1). Stratigrafi daerah penelitian dapat dibagi menjadi lima satuan batuan dari tua ke muda, antara lain Satuan Metapsamit Mentulu berumur Perm, Satuan Konglomerat Lemat berumur Oligosen Atas, Satuan Batupasirkerikilan – vulkanik Lemat berumur Oligosen Atas, Satuan Batulempung – vulkanik Benakat berumur Oligosen Atas – Miosen Bawah dan Satuan Batupasir – vulkanik Benakat berumur Oligosen Atas – Miosen Bawah.Struktur geologi yang berkembang berupa kekar, sesar dengan arah relatif Timurlaut – Baratdaya danTenggara – Baratlaut. Hasil analisis fasies yang dilakukan pada tiap satuan batuan, antara lain Satuan Konglomerat Lemat dijumpai elemen arsitektural berupa SG (Sediment gravity flow deposits) dan SB (Sand bedforms). SatuanBatupasirkerikilan-vulkanik Lemat dijumpai elemen arsitektural berupa CH  (Channel), SG (Sediment gravity flow deposits), SB (Sand bedforms), FF (Floodplain fines) dan GB (Gravel bedforms). Satuan Batulempungvulkanik Benakat dijumpai elemen arsitektural berupa FF (Floodplain fines). Satuan Batupasir-vulkanik Benakat dijumpai elemen arsitektural berupa FF (Floodplain fines), SB (Sand bedforms), GB (Gravel bedforms) dan CS (Crevasse splay).Kata-kata Kunci : fasies, elemen arsitektural, Formasi Lemat

    Surface and Sub-Surface Composition and Properties of Ion-Bombarded Lithium Alloys

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    Lithium-bearing alloys such as Si-Li, Al-Li and Cu-Li are of importance in a variety of technological applications, many of them depending on the fact that the surface composition of these alloys differs significantly from that of the bulk, both at thermal equilibrium and under ion bombardment. During ion sputtering, these materials exhibit a variety of phenomena which affect the surface composition and concentration depth profile in a complex manner. We present here experimental measurements of the surface and near-surface composition profiles of sputtered Cu-Li and Al-Li alloys. The experimental results are interpreted in terms of surface loss and radiation-induced segregation processes. Emphasis is placed on the use of these materials for use as plasma-interactive components in magnetic-confinement fusion applications

    Intermittent preventive therapy for malaria: arguments in favour of artesunate and sulphamethoxypyrazine - pyrimethamine combination

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    Recent publications put a serious warning regarding the inefficacy of sulphadoxine-pyrimethamine (SP) for the intermittent preventive treatment of malaria in young children (IPTi). Recommendations for other therapies are being made. By using a different and better sulphonamide (sulphamethoxypyrazine), it is possible to manufacture fixed dose combination pills with artesunate and pyrimethamine. This combination permits a full therapy over 24 hours (dosing interval being 12 hours). It is recommended that this combination should be tested in future field studies of IPTi

    Seasonal use case for the RTS,S/AS01 malaria vaccine: a mathematical modelling study

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    BACKGROUND: A 2021 clinical trial of seasonal RTS,S/AS01E (RTS,S) vaccination showed that vaccination was non-inferior to seasonal malaria chemoprevention (SMC) in preventing clinical malaria. The combination of these two interventions provided significant additional protection against clinical and severe malaria outcomes. Projections of the effect of this novel approach to RTS,S vaccination in seasonal transmission settings for extended timeframes and across a range of epidemiological settings are needed to inform policy recommendations. METHODS: We used a mathematical, individual-based model of malaria transmission that was fitted to data on the relationship between entomological inoculation rate and parasite prevalence, clinical disease, severe disease, and deaths from multiple sites across Africa. The model was validated with results from a phase 3b trial assessing the effect of SV-RTS,S in Mali and Burkina Faso. We developed three intervention efficacy models with varying degrees and durations of protection for our population-level modelling analysis to assess the potential effect of an RTS,S vaccination schedule based on age (doses were delivered to children aged 6 months, 7·5 months, and 9 months for the first three doses, and at 27 months of age for the fourth dose) or season (children aged 5-17 months at the time of first vaccination received the first three doses in the 3 months preceding the transmission season, with any subsequent doses up to five doses delivered annually) in seasonal transmission settings both in the absence and presence of SMC with sulfadoxine-pyrimethamine plus amodiaquine. This is modelled as a full therapeutic course delivered every month for four or five months of the peak in transmission season. Estimates of cases and deaths averted in a population of 100 000 children aged 0-5 years were calculated over a 15-year time period for a range of levels of malaria transmission intensity (Plasmodium falciparum parasite prevalence in children aged 2-10 years between 10% and 65%) and over two west Africa seasonality archetypes. FINDINGS: Seasonally targeting RTS,S resulted in greater absolute reductions in malaria cases and deaths compared with an age-based strategy, averting an additional 14 000-47 000 cases per 100 000 children aged 5 years and younger over 15 years, dependent on seasonality and transmission intensity. We predicted that adding seasonally targeted RTS,S to SMC would reduce clinical incidence by up to an additional 42 000-67 000 cases per 100 000 children aged 5 years and younger over 15 years compared with SMC alone. Transmission season duration was a key determinant of intervention effect, with the advantage of adding RTS,S to SMC predicted to be smaller with shorter transmission seasons. INTERPRETATION: RTS,S vaccination in seasonal settings could be a valuable additional tool to existing interventions, with seasonal delivery maximising the effect relative to an age-based approach. Decisions surrounding deployment strategies of RTS,S in such settings will need to consider the local and regional variations in seasonality, current rates of other interventions, and potential achievable RTS,S coverage. FUNDING: UK Medical Research Council, UK Foreign Commonwealth & Development Office, The Wellcome Trust, and The Royal society

    proton-deuteron elastic scattering above the deuteron breakup

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    The complex Kohn variational principle and the (correlated) hyperspherical harmonics method are applied to study the proton-deuteron elastic scattering at energies above the deuteron breakup threshold. Results for the elastic cross section and various elastic polarization observables have been obtained by fully taking into account the long-range effect of the Coulomb interaction and using a realistic nucleon-nucleon interaction model. Detailed comparison between the theoretical predictions and the accurate and abundant proton-deuteron experimental data can now be performed.Comment: 6 pages, 2 figure

    Faddeev Calculations of Proton-Deuteron Radiative Capture with Exchange Currents

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    pd capture processes at various energies have been analyzed based on solutions of 3N-Faddeev equations and using modern NN forces. The application of the Siegert theorem is compared to the explicit use of π\pi- and ρ\rho-like exchange currents connected to the AV18 NN interaction. Overall good agreement with cross sections and spin observables has been obtained but leaving room for improvement in some cases. Feasibility studies for 3NF's consistently included in the 3N continuum and the 3N bound state have been performed as well.Comment: Minor changes in notation, ps files for figure

    The one-pion-exchange three-nucleon force and the AyA_y puzzle

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    We consider a new three-nucleon force generated by the exchange of one pion in the presence of a 2N correlation. The underlying irreducible diagram has been recently suggested by the authors as a possible candidate to explain the puzzle of the vector analyzing powers AyA_y and iT11iT_{11} for nucleon-deuteron scattering. Herein, we have calculated the elastic neutron-deuteron differential cross section, AyA_y, iT11iT_{11}, T20T_{20}, T21T_{21}, and T22T_{22} below break-up threshold by accurately solving the Alt-Grassberger-Sandhas equations with realistic interactions. We have also studied how AyA_y evolves below 30 MeV. The results indicate that this new 3NF diagram provides one possible additional contribution, with the correct spin-isospin structure, for the explanation of the origin of this puzzle.Comment: revised version: We have also studied how Ay evolves below 30 MeV, 4 Pages (twocolumn), 2 figures, uses psfig, RevTe
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