516 research outputs found

    Proliferation of anomalous symmetries in colloidal monolayers subjected to quasiperiodic light fields

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    Quasicrystals provide a fascinating class of materials with intriguing properties. Despite a strong potential for numerous technical applications, the conditions under which quasicrystals form are still poorly understood. Currently, it is not clear why most quasicrystals hold 5- or 10-fold symmetry but no single example with 7 or 9-fold symmetry has ever been observed. Here we report on geometrical constraints which impede the formation of quasicrystals with certain symmetries in a colloidal model system. Experimentally, colloidal quasicrystals are created by subjecting micron-sized particles to two-dimensional quasiperiodic potential landscapes created by n=5 or seven laser beams. Our results clearly demonstrate that quasicrystalline order is much easier established for n = 5 compared to n = 7. With increasing laser intensity we observe that the colloids first adopt quasiperiodic order at local areas which then laterally grow until an extended quasicrystalline layer forms. As nucleation sites where quasiperiodicity originates, we identify highly symmetric motifs in the laser pattern. We find that their density strongly varies with n and surprisingly is smallest exactly for those quasicrystalline symmetries which have never been observed in atomic systems. Since such high symmetry motifs also exist in atomic quasicrystals where they act as preferential adsorption sites, this suggests that it is indeed the deficiency of such motifs which accounts for the absence of materials with e.g. 7-fold symmetry

    Uji Aktivitas Antioksidan Menggunakan Radikal 1,1-difenil-2- Pikrilhidrazil dan Penetapan Kandungan Fenolik Total Fraksi Etil Asetat Ekstrak Etanol Buah Anggur Bali (Vitis Vinifera L.)

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    This research was conducted to determine the antioxidant activity of ethyl acetat fraction of extract of Balinesse grape (Vitis vinifera L.) using free radical and determine the total phenolic content. Balinesse grape was extracted with ethanol and then fractionated using ethyl acetate. Free radical scavenging activity was tested by measuring the DPPH radical scavenging activity. Total phenolic content was determined using the Folin-Ciocalteau method measured the concentration of phenolic content in gallic acid total equivalents using unit's mg/g. The mean IC50 value for DPPH radical scavenging activity of the ethyl acetat fraction of ethanolic extract of Balinesse grape was found to be 36.55 ± 0.09 µg/mL. The phenolic content was ranging from 3.23 ± 0.02 mg gallic acid equivalents per gram of ethyl acetat fraction of ethanolic extract of Balinesse grape

    A Tale of Two Tilings

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    What do you get when you cross a crystal with a quasicrystal? The surprising answer stretches from Fibonacci to Kepler, who nearly 400 years ago showed how the ancient tiles of Archimedes form periodic patterns.Comment: 3 pages, 1 figur

    Archimedean-like colloidal tilings on substrates with decagonal and tetradecagonal symmetry

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    Two-dimensional colloidal suspensions subject to laser interference patterns with decagonal symmetry can form an Archimedean-like tiling phase where rows of squares and triangles order aperiodically along one direction [J. Mikhael et al., Nature 454, 501 (2008)]. In experiments as well as in Monte-Carlo and Brownian dynamics simulations, we identify a similar phase when the laser field possesses tetradecagonal symmetry. We characterize the structure of both Archimedean-like tilings in detail and point out how the tilings differ from each other. Furthermore, we also estimate specific particle densities where the Archimedean-like tiling phases occur. Finally, using Brownian dynamics simulations we demonstrate how phasonic distortions of the decagonal laser field influence the Archimedean-like tiling. In particular, the domain size of the tiling can be enlarged by phasonic drifts and constant gradients in the phasonic displacement. We demonstrate that the latter occurs when the interfering laser beams are not adjusted properly

    Studi Konfigurasi Lambung Kapal Trimaran Dengan Bantuan Computational Fluid Dynamic (Cfd)

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    Kebutuhan kapal cepat meningkat untuk itu diperlukan kapal dengan bentuk lambungtrimaran. Kapal dengan bentuk lambung yang baik mempunyai hambatan kecil. Hal inimemberikan dampak baik untuk operasional dan olah gerak kapal. Penelitian ini bertujuanuntuk mendapatkan konfigurasi kapal Trimaran yang menghasilkan hambatan paling kecildengan menggunakan bantuan software Computational Fluid Dynamic (CFD). Denganmemprediksi posisi dan bentuk sidehull, maka akan didapat bentuk dan posisi sidehull yangefektif, sehingga bentuk aliran yang dilewati oleh kapal tidak menghambat laju kapal terhadapair. Posisi sidehull akan ditentukan secara memanjang, sementara bentuk sidehullmenggunakan bentuk simetris dan asimetris. Dari beberapa konfigurasi tersebut akandihasilkan satu model kapal yang baik. Penelitian ini menghasilkan hambatan yang terkecilpada konfigurasi kapal Trimaran simetri 1B (3,6 m) strut 2 m dengan kecepatan 15 knot,sementara pada kecepatan 25 knot, hambatan terkecil pada kapal simetri 1,25 B (4,5 m) strut 2m. Hambatan terkecil terdapat pada bentuk simetri pada setiap kecepatan

    Isatuximab plus carfilzomib/dexamethasone versus carfilzomib/dexamethasone in patients with relapsed/refractory multiple myeloma: IKEMA Phase III study design

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    Although the treatment of relapsed/refractory multiple myeloma has improved dramatically over the past decade, the disease remains incurable; therefore, additional therapies are needed. Novel combination therapies incorporating monoclonal antibodies have shown significant promise. Here we describe the design of a Phase III study (NCT03275285, IKEMA), which is evaluating isatuximab plus carfilzomib and low-dose dexamethasone, versus carfilzomib/dexamethasone in relapsed/refractory multiple myeloma. The primary end point is progression-free survival. Responses are being determined by an independent review committee using 2016 International Myeloma Working Group criteria, and safety will be assessed throughout. The first patient was recruited in November 2017, and the last patient was recruited in March 2019; 302 patients have been randomized, and the study is ongoing. / Clinical trial registration: NCT0327528

    An overview of treatment options for patients with relapsed/refractory multiple myeloma and renal impairment

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    Renal impairment (RI) is a relatively common complication of multiple myeloma, which increases in frequency as disease becomes more advanced and recovery of renal function becomes less likely as patients progress through lines of therapy. Clinical trials in the relapsed/refractory multiple myeloma (RRMM) setting have not uniformly included patients with RI or robustly reported their outcomes. Here, we review existing data among patients with RI and RRMM across drug classes (including immunomodulatory agents, proteasome inhibitors, monoclonal antibodies, antibody-drug conjugates, chimeric antigen receptor T-cell therapies, and exportin-1 inhibitor) to provide an improved understanding of available treatment options for this important population. We highlight data from pivotal clinical trials, including data relating to renal response (as defined by the International Myeloma Working Group) and discuss real-world experiences in patients with RI, where applicable. Despite substantial advances in RRMM treatment, the presence of RI remains associated with reduced overall survival. Consistent inclusion of patients with RI, and uniform reporting of their outcomes, should be encouraged in future prospective trials of treatments for RRMM
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