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Two Step Graph Protection Game
No full textThe two-step graph protection game is a two-player game played on an n-vertex graph G, where one player is the attacker and the second player is the defender. The defender has k guards which he places on some vertices of the graph at the beginning of the game. In each move, the attacker attacks an edge. The defender moves the guards in such a manner that each guard can move at most two steps (along two adjacent edges) without retracing his previous step and one of the guards must move along the attacked edge. If such a movement is not possible after a finite sequence of attacks, the attacker wins. If the defender is able to defend the graph for an infinite sequence of attacks, the defender wins. We define the minimum number of guards for which the defender has a winning strategy, as the two- step protection number of a graph G and denote it by tsn(G). We show that it is NP-hard to decide whether tsn(G)≤k for a given graph G and integer k and this problem is also W[2]-hard parameterized by k. We compute the tsn(G) for some graph classes, i.e., stars, paths, cycles, complete graphs, complete bipartite graphs and split graphs. We also generalize these results to a game where the guards can move for at most r steps (without retracing) where r is less than the diameter of the graph
Facile colloidal route to prepare hierarchical micro-nanoporous MgO stabilized ZrO2
No full textFabrication of sintered pure ZrO2ceramics result in the generation of cracks due to 3–5 % volume expansion associated with the phase transformation of tetragonal phase (t-ZrO2) to monoclinic phase (m-ZrO2) during cooling. Typically, Y2O3, MgO, CaO, CeO2are added as dopants to stabilize and produce crack free ZrO2. Herein, we developed a single-step colloidal processing route for in-situ generation of MgO nanoparticles by hydrolysis and calcination reactions of magnesium acetate precursor present in the aqueous ZrO2slurry, that aids in manufacturing of crack-free ZrO2compact. X-ray diffraction analyses of sintered pure ZrO2showed 36 % t-ZrO2and 64 % m-ZrO2, while MgO doped ZrO2revealed 36–37 % t-ZrO2, 31–35 % m-ZrO2, 14–19 % cubic phase (c-ZrO2) and 13–15 % Mg2Zr5O12. The cubic phases and Mg2Zr5O12are responsible for reducing the lattice strain as shown by the Williamson-Hall analyses. Interestingly, addition of microparticles of ZrO2to MgO doped Zirconia further led to reduction of the lattice strain. Hierarchical micro-nanoporous MgO doped ZrO2specimens were fabricated by using sacrificial poly(methyl methacrylate) (PMMA) beads (6 μm diameter) in the slurry. The porosity amount and pore diameters were systematically controlled by interplay of PMMA amount (1, 5, 10 vol %) and sintering temperatures (1100, 1200, 1300 °C). Such hierarchical micro-nano porous ZrO2could be beneficial in the fields of biomedicine, membrane technology, sensors, energy storage, and thermal barriers applications
Modified tractive force approach for sediment transport under bank seepage
No full textThe current research focuses on integrating the impact of seepage into the tractive force method for sediment particles situated on porous riverbanks. A formula is developed using the tractive force approach to calculate the critical shear stress acting on sediment particles under steady seepage conditions. The study reveals that the hydraulic gradient influences the critical shear stress, which rises with higher hydraulic gradients. Additionally, application of the derived equation is demonstrated through a hypothetical channel design problem
Fluorescent Polyamines for Efficient DNA Condensation and Cellular Uptake
No full textPolyamine-based carriers, including spermine and spermidine, offer significant potential due to their ability to bind DNA and facilitate cellular uptake. In this study, four fluorophore-tagged spermidine and spermine derivatives (S1C, S2C, S1D, S2D) linked by a non-cleavable linker are synthesized and evaluated for their ability to condense DNA and mediate gene delivery. Spectroscopic and bio-AFM studies confirm the DNA condensation, with S2C exhibiting selective lysosomal targeting and photostability for up to 2 h. Further validation using an RFP-tagged plasmid confirms S2C’s effective DNA internalization. This approach offers a promising, straightforward alternative for gene delivery, addressing key limitations of conventional methods. However, further optimization is needed to improve gene release and enhance the therapeutic efficacy
Active-Learning Assisted General Framework for Efficient Parameterization of Force-Fields
No full textThis work presents an efficient approach to optimizing force field parameters for sulfone molecules using a combination of genetic algorithms (GA) and Gaussian process regression (GPR). Sulfone-based electrolytes are of significant interest in energy storage applications, where accurate modeling of their structural and transport properties is essential. Traditional force field parametrization methods are often computationally expensive and require extensive manual intervention. By integrating GA and GPR, our active learning framework addresses these challenges by achieving optimized parameters in 12 iterations using only 300 data points, significantly outperforming previous attempts requiring thousands of iterations and parameters. We demonstrate the efficiency of our method through a comparison with state-of-the-art techniques, including Bayesian Optimization. The optimized GA-GPR force field was validated against experimental and reference data, including density, viscosity, diffusion coefficients, and surface tension. The results demonstrated excellent agreement between GA-GPR predictions and experimental values, outperforming the widely used OPLS force field. The GA-GPR model accurately captured both bulk and interfacial properties, effectively describing molecular mobility, caging effects, and interfacial arrangements. Furthermore, the transferability of the GA-GPR force field across different temperatures and sulfone structures underscores its robustness and versatility. Our study provides a reliable and transferable force field for sulfone molecules, significantly enhancing the accuracy and efficiency of molecular simulations. This work establishes a strong foundation for future machine learning-driven force field development, applicable to complex molecular systems
Uncovering the Hidden Physical Structures and Protostellar Activities in the Low-metallicity S284-RE Region: Results from ALMA and JWST
No full textWe present an observational study of the S284-RE region, a low-metallicity area associated with the extended S284 H ii region. A thermally supercritical filament (mass ∼2402 M⊙ and length ∼8.5 pc) is investigated using the Herschel column density map. The Spitzer ratio 4.5 μm/3.6 μm map traces the H2 outflows in this filament, where previously reported young stellar objects (YSOs) are spatially distributed. Analysis of the YSO distribution has revealed three active star-forming clusters (YCl1, YCl2, and YCl3) within the filament. YCl3 seems to be the most evolved and YCl2 the youngest, while YCl1 displays signs of nonthermal fragmentation. The JWST (F470N+F444W)/F356W ratio map reveals at least seven bipolar H2 outflows, with four (olc1-olc4) in YCl1 and three (ol1-ol3) in YCl2. The driving sources of these outflows are identified based on outflow geometry, Atacama Large Millimeter/submillimeter Array (ALMA) continuum peaks, and YSO positions. Two ALMA continuum sources—#2 and #3—from the M-Reff plot are recognized as potential massive star formation candidates. ALMA continuum source #2 hosts at least three outflow-driving sources, whereas ALMA continuum source #3 contains two. The bipolar outflow olc1, driven by an embedded object within continuum source #2, is likely a massive protostar, as indicated by the Br-α and PAH emissions depicted in the JWST (F405N+F444W)/F356W ratio map. The presence of H2 knots in the outflows olc1 and ol1 suggests episodic accretion. Overall, the study investigates a massive protostar candidate, driving the ∼2.7 pc H2 outflow olc1 and undergoing episodic accretion
Adaptive body biasing technique based digital LDO regulator for transient response improvement
No full textThis paper introduces an adaptive body biasing (ABB) technique for improving the transient response of the Digital Low-Dropout regulator (DLDO) during events of step increment in the load current demand. The proposed ABB technique detects voltage undershoot and dynamically tunes the body bias of the pMOSFETs in the DLDO's switching array to reduce its threshold voltage, thereby boosting the current supply to help meet the transient load demand. With an ABB-integrated DLDO, designed and simulated in a 28 nm FDSOI (RVT) process, we achieve a reduction in the peak output voltage undershoot and recovery time by 21.23 % and 41.13 %, respectively, compared to DLDO operation without ABB. To validate our approach in the bulk CMOS process, we also designed the ABB-integrated DLDO in a 180 nm bulk process and reported a reduction in the peak output voltage undershoot and recovery time by 13.69 % and 43.8 %, respectively. The robustness of the design to mismatches and process variations is justified via Monte-Carlo simulations, indicating the reliable performance of the proposed ABB technique in DLDO
Viscous heating in sediments as a 'Zeroing' mechanism in luminescence dating of sand dikes for paleoseismological investigations
No full textThis contribution examines the possibility of directly determining the timing of paleoseismic events by luminescence dating of sediments in sand dikes. Sand dikes are water escape structures (liquefaction features) formed in soft sediments due to the passage of seismically generated Rayleigh waves. Blending earlier studies of a crack dilatation model for the creation of sand dikes (Levi et al., 2008) and the studies on sonication of crystal slurries (Eddingsaas and Suslick, 2006), we posit that kinematic viscosity during the injection of liquefied sediments leads to a local transient heating of the injected material. Theoretical analysis of the injection process developed in this study shows that the instantaneous viscous flow of a sediment-water mixture through cracks in the overlying sedimentary strata can generate local temperatures of 350 °C or even more. Such temperatures can reset the luminescence signal of quartz grains in the liquefied sediments. Thereafter, the luminescence signal acquired by the quartz grains from their ambient natural radiation environment enables direct dating of these sediments; i.e. the timing of the causal earthquake. Given that the injection velocity (and hence the temperature rise) is highest at the centre of a dike, the sampling was from the core region of dikes. Changes in the thermoluminescence sensitivity of the 110 °C glow peak of quartz (Sunta and David, 1982) were used to confirm that the viscous heating during sand dike formation did result in temperatures ≥ 350 °C. Stratigraphic consistency of luminescence ages of the dikes, the source sediments and their concordance with the published radiocarbon ages confirms the applicability of luminescence for their dating and provide evidence of three large earthquakes ∼0.30 ± 0.03, 1.0 ± 0.10 and ≥ 1.5 ka ago
Synthesis and in vitro assessment of Triazole-based compounds as potential inhibitors of herpes simplex virus type 1
No full textA library of novel 1,2,4-triazole derivatives fused with a pyrazine moiety (5a�5t) was successfully synthesized and evaluated for their therapeutic potential against HSV-I virus and oxidative stress. These compounds were assessed for anti-inflammatory, antioxidant, and anti-HSV activities, demonstrating encouraging biological profiles. In particular, compounds 5f and 5t exhibited markedly improved antiviral efficacy compared to the reference drug, Acyclovir. The antioxidant capacity was also notable, with compound 5b showing exceptional radical scavenging potential. To better understand the interaction at the molecular level, docking studies were conducted, indicating that these molecules could potentially inhibit HSV1, a key enzyme required for viral replication. Also, in silico testing was conducted for assessing drug-likeness, ADME characteristics, and stability of metabolism which was helpful for optimizing further lead designs. Although the experimental methods were accurately implemented, some human error such as timing during administration of the compounds, measuring, and other tasks may have slight variations which are not entirely avoidable. These possible blunders are, however, unlikely to change significantly the observed trends. Ultimately, the study emphasizes these new hybrids of triazole-pyrazine as potential precursors for the synthesis of powerful anti-HSV-I and possibly antibacterial medicines, which require more advanced pharmacological and clinical research
Experimental investigation of lift-up and instability of the viscous flow induced by a rotating cone-cylinder in an enclosure
No full textThis paper probes into the flow induced by a rotating cone-cylinder model in an enclosure. Two component particle image velocimetry measurements in the symmetry plane reveal that the rotating cone-cylinder causes an outward jet on the cylinder section, which lifts the rotating boundary layers away from the wall. A large-scale counter-rotating vortex pair sets up with its mutual upwash aligned with the lift-up region. Furthermore, the centrifugal instability induces Taylor vortices in the rotating boundary layer, which are convected by the mean flow field and are lifted away from the surface, causing a high standard deviation. The lift-up phenomenon shows two preferred axial locations: below a critical Reynolds number Re_{b,c}, the lift-up occurs close to the cone-cylinder junction, and for Reynolds number higher than Re_{b,c} lift-up is pushed away from the cone-cylinder junction, towards the model base. The value of the critical Reynolds number Re_{b,c} lies within 2 \times 10^3-2.5 \times 10^3 for the investigated cases