225 research outputs found
Dilute magnetic semiconductor and half metal behaviors in 3d transition-metal doped black and blue phosphorenes: a first-principles study
We present first-principles density-functional calculations for the
structural, electronic, and magnetic properties of substitutional 3d transition
metal (TM) impurities in two-dimensional black and blue phosphorenes. We find
that the magnetic properties of such substitutional impurities can be
understood in terms of a simple model based on the Hund's rule. The TM-doped
black phosphorenes with Ti, V, Cr, Mn, Fe and Ni impurities show dilute
magnetic semiconductor (DMS) properties while those with Sc and Co impurities
show nonmagnetic properties. On the other hand, the TM-doped blue phosphorenes
with V, Cr, Mn and Fe impurities show DMS properties, those with Ti and Ni
impurities show half-metal properties, whereas Sc and Co doped systems show
nonmagnetic properties. We identify two different regimes depending on the
occupation of the hybridized electronic states of TM and phosphorous atoms: (i)
bonding states are completely empty or filled for Sc- and Co-doped black and
blue phosphorenes, leading to non-magnetic; (ii) non-bonding d states are
partially occupied for Ti-, V-, Cr-, Mn-, Fe- and Ni-doped black and blue
phosphorenes, giving rise to large and localized spin moments. These results
provide a new route for the potential applications of dilute magnetic
semiconductor and half-metal in spintronic devices by employing black and blue
phosphorenes.Comment: 9 pages, 7 figure
Identification of a sub-micromolar, non-peptide inhibitor of β-secretase with low neural cytotoxicity through in silico screening
Nowadays identification of novel non-peptide β-secretase (BACE-1, hereinafter) inhibitors with low cytotoxicity and good blood–brain barrier (BBB) property holds common interest of drug discovery for Alzheimer’s disease. Twenty SPECS compounds were tested in BACE-1 FRET assays and methylthiazoletetrazolium (MTT) cytotoxicity experiment. Two compounds: 2 and 15 demonstrated IC50 values of 0.53 and 9.4 μM. In addition, 2 showed least toxic effect to the neuroblastoma cells. The results from both in silico and in vitro studies provided new pharmacophoric entities for chemical synthesis and optimization on the current discovered BACE-1 small molecule inhibitors
Molecular docking and structure-activity relationship studies on benzothiazole based non-peptidic BACE-1 inhibitors
A similarity search on the structural analogs of an inhibitor of BACE-1 with IC50 2.8 μM, which contained a P1 benzothiazole group together with a triazine ring linked by a secondary amine group, was described in this Letter and some more potent inhibitors against BACE-1 were identified. The most potent compound 5 (IC50 = 0.12 μM) increases the inhibitory potency by 24 folds. Our results suggest that a pyrrolidinyl side group at the P3′ and P4′ of the inhibitors are favored for strong inhibition and a small aromatic group at the P4 position is also essential to the potency
DREAMPlaceFPGA-MP: An Open-Source GPU-Accelerated Macro Placer for Modern FPGAs with Cascade Shapes and Region Constraints
FPGA macro placement plays a pivotal role in routability and timing closer to
the modern FPGA physical design flow. In modern FPGAs, macros could be subject
to complex cascade shape constraints requiring instances to be placed in
consecutive sites. In addition, in real-world FPGA macro placement scenarios,
designs could have various region constraints that specify boundaries within
which certain design instances and macros should be placed. In this work, we
present DREAMPlaceFPGA-MP, an open-source GPU-accelerated FPGA macro-placer
that efficiently generates legal placements for macros while honoring cascade
shape requirements and region constraints. Treating multiple macros in a
cascade shape as a large single instance and restricting instances to their
respective regions, DREAMPlaceFPGA-MP obtains roughly legal placements. The
macros are legalized in multiple steps to efficiently handle cascade shapes and
region constraints. Our experimental results demonstrate that DREAMPlaceFPGA-MP
is among the top contestants of the MLCAD 2023 FPGA Macro-Placement Contest
A universal and improved mutation strategy for iterative wavefront shaping
Recent advances in iterative wavefront shaping (WFS) techniques have made it
possible to manipulate the light focusing and transport in scattering media. To
improve the optimization performance, various optimization algorithms and
improved strategies have been utilized. Here, a novel guided mutation (GM)
strategy is proposed to improve optimization efficiency for iterative WFS. For
both phase modulation and binary amplitude modulation, considerable
improvements in optimization effect and rate have been obtained using multiple
GM-enhanced algorithms. Due of its improvements and universality, GM is
beneficial for applications ranging from controlling the transmission of light
through disordered media to optical manipulation behind them.Comment: 5 pages with 6 figure
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