The measurement of the production of charm jets, identified by the presence of a D$^{0}$ meson in the jet constituents, is presented in proton–proton collisions at centre-of-mass energies of $ ...\sqrt{s} $ = 5.02 and 13 TeV with the ALICE detector at the CERN LHC. The D$^{0}$ mesons were reconstructed from their hadronic decay D$^{0}$ → K$^{−}$π$^{+}$ and the respective charge conjugate. Jets were reconstructed from D$^{0}$-meson candidates and charged particles using the anti-k$_{T}$ algorithm, in the jet transverse momentum range 5 < p$_{T,chjet}$< 50 GeV/c, pseudorapidity |η$_{jet}$| < 0.9 − R, and with the jet resolution parameters R = 0.2, 0.4, 0.6. The distribution of the jet momentum fraction carried by a D$^{0}$ meson along the jet axis $ \left({z}_{\Big\Vert}^{\textrm{ch}}\right) $ was measured in the range 0.4 <$ {z}_{\Big\Vert}^{\textrm{ch}} $< 1.0 in four ranges of the jet transverse momentum. Comparisons of results for different collision energies and jet resolution parameters are also presented. The measurements are compared to predictions from Monte Carlo event generators based on leading-order and next-to-leading-order perturbative quantum chromodynamics calculations. A generally good description of the main features of the data is obtained in spite of a few discrepancies at low p$_{T,chjet}$. Measurements were also done for R = 0.3 at $ \sqrt{s} $ = 5.02 and are shown along with their comparisons to theoretical predictions in an appendix to this paper.graphic not available: see fulltext
The first measurement of the production of pions, kaons, (anti-)protons and ϕ mesons at midrapidity in Xe–Xe collisions at $\sqrt{s_{NN}}$ = 5.44 TeV is presented. Transverse momentum ...(pT) spectra and pT-integrated yields are extracted in several centrality intervals bridging from p–Pb to mid-central Pb–Pb collisions in terms of final-state multiplicity. The study of Xe–Xe and Pb–Pb collisions allows systems at similar charged-particle multiplicities but with different initial geometrical eccentricities to be investigated. A detailed comparison of the spectral shapes in the two systems reveals an opposite behaviour for radial and elliptic flow. In particular, this study shows that the radial flow does not depend on the colliding system when compared at similar charged-particle multiplicity. In terms of hadron chemistry, the previously observed smooth evolution of particle ratios with multiplicity from small to large collision systems is also found to hold in Xe–Xe. In addition, our results confirm that two remarkable features of particle production at LHC energies are also valid in the collision of medium-sized nuclei: the lower proton-to-pion ratio with respect to the thermal model expectations and the increase of the ϕ-to-pion ratio with increasing final-state multiplicity.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
► Particle distribution in Al–TiC in situ composite was homogenized by friction stir processing. ► FSP also refined the as-cast grain size. ► Double pass FSP yielded finer grain size. ► Mechanical ...properties improved significantly after FSP. ► While the strength and hardness increased substantially the ductility was not compromised.
Aluminium based in situ composites have many advantages over their conventional counterparts. However, a major problem in such composites is the segregation of the in situ formed particles at the grain boundaries. In this study, it has been shown for the first time that friction stir processing (FSP) can be used effectively to homogenise the particle distribution in Al based in situ composites. An Al-5
wt.% TiC composite was processed in situ using a mixture of K
2TiF
6 and graphite powders in aluminium melt. Friction stir processing was employed on the as-cast composite to uniformly distribute the TiC particles in the Al matrix. The composite was subjected to single and double pass FSP and its effect on the microstructure and properties was evaluated. A single pass of FSP was enough to break the particle segregation from the grain boundaries and improve the distribution. Two passes of FSP resulted in complete homogenization and elimination of casting defects. The grain size was also refined after each FSP pass. This led to significant improvement in the mechanical properties. The novel feature of the composite is that while the strength and hardness improved substantially after FSP, the ductility was not compromised.
Copper particles were incorporated and retained in elemental state in an aluminium matrix by friction stir processing thereby producing a non-equilibrium particulate composite. The processed Al-Cu
p
...composite exhibited improved strength with significantly high ductility. The composite was stable up to a temperature of more than 300°C. Thermal exposure at 350°C for more than 10 min led to diffusion of Cu atoms into the Al matrix forming a core-shell type structure in the Cu particles and thus producing an Al-Cu core-shell composite. The shell consists of multiple layers, the thickness of which was controllable.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Heavy haul railways are increasingly being subjected to operating conditions that demand better performance of the materials, with speeds of operation and loads increasing to comply with the large ...demand for transportation. For joining of rails, the Flash Butt Welding (FBW) process stands out due to the higher quality of the joint with respect to thermite welding. However, the properties of the rails may be compromised because of improper parameterization of the welding process and the appearance of defects in the welded joint, as well as heterogeneities in the Heat Affected Zone (HAZ). In this work, a statistically planned experimental array was used to study four parameters of the FBW process (pulse current, number of pulses, upsetting force, and equivalent carbon) on Premium and Super Premium rail steels. The array generated eight different welding conditions. The results made it possible to understand the relationship between the microstructure and the microhardness maps on the longitudinal section of the welded joint. Fracture analysis showed the fracture mechanisms for each welding condition. The Premium rails showed double-necking in the partial austenitization region while Super Premium rails showed brittle fracture, except for the more extreme welding condition. Additionally, two welding conditions showed double-necking in the partial austenitization region, but with brittle fracture outside the necking region. Tensile tests showed that the welding condition that corresponds the highest heat input presented the worst mechanical behavior for applications on railroads and the welding conditions with lowest heat input presented the best behavior.
To evaluate the protective activity of allylpyrocatechol (APC), the major antioxidant constituent of Piper betel, against the indomethacin-induced stomach ulceration in the rat model and correlates ...with its antioxidative and mucin protecting properties.
Male Sprague-Dawley rats were divided into five groups. Normal control rats (group I) were given the vehicle oral dose of gum acacia in distilled water (1 mL per rat); ulcerated control and treated rats (groups II-V) were given a single dose of indomethacin (30 mg/kg body wt.); group II rats were sacrificed 4 h after indomethacin administration; groups III-V rats were given the vehicle (1 mL per rat) or APC (2 mg/kg body wt.) or misoprostol (1.43 mug/kg body wt.) once daily by oral intubation for 7 d starting from 4 h after the indomethacin administration. After 7 d, the stomach tissues were excised for histological examination and biochemical analysis.
Treatment with APC (2 mg/kg body wt per day) and misoprostol (1.43 mug/kg body wt per day) for 7 d could effectively heal the stomach ulceration as revealed from the ulcer index and histopathological studies. Compared to the zero day ulcerated group, treatment with APC and misoprostol reduced the ulcer index by 93.4% and 85.4% respectively (P < 0.05). Both APC and misoprostol accelerated ulcer healing observed in natural recovery (P < 0.05), their respective healing capacities not being significantly different. The healing capacities of APC and misoprostol could be attributed to their antioxidant activity as well as the ability to enhance the mucin content of the gastric tissues. Compared to the ulcerated untreated rats, those treated with APC and misoprostol showed near normal MDA levels, while the protein levels were 86% and 78% of the normal value respectively (P < 0.05). Likewise, both APC and misoprostol increased the SOD, catalase, and mucin levels significantly (P < 0.05), the effect of APC being better.
APC can protect indomethacin-induced gastric ulceration due to its antioxidative and mucin protecting properties.
A family of nanostructured morphologies made of poly(cholesteroyl methacrylate)-b-poly(styrene) (PCMA-b-PS) copolymers were prepared via reversible addition–fragmentation chain transfer (RAFT) ...dispersion. The number-average degree of polymerization (DP n ) of the PS segment was targeted from 15 to 150 to obtain spherical, wormlike, fibrillar, and vesicular nano-objects as evidenced from field emission scanning electron microscopy and transmission electron microscopy, supported by dynamic light scattering experiments. Numerous morphologies were also observed by increasing the total solid content (5–25 wt %) of the copolymer. Thermoreversible gel–sol transition was studied with a higher wt % of copolymers. The experimental observations were further supported by computer simulations using dissipative particle dynamics. The developed coarse-grain model, accounting for both the graft architecture and structural heterogeneity of the lyophilic block, made it possible to evaluate the morphological transitions in a block copolymer solution at different block length ratios, different total solid contents, and temperatures to provide an in-depth understanding of the experimental results.
Friction stir processing was carried out on commercially pure aluminium, and a detailed microstructural characterisation was performed by electron backscattered diffraction and transmission electron ...microscopy. Friction stir processing resulted in significant grain refinement with narrow grain size distribution. The microstructure showed fine and equiaxed grains, with some ultrafine grains being also observed. Electron backscattered diffraction studies showed majority of the boundaries to be high angle, confirming the occurrence of dynamic recrystallisation (DRX). Transmission electron microscopy observations revealed dislocation arrangement into subgrain boundaries, grains having different dislocation densities and in different stages/degrees of recovery. Electron backscattered diffraction analysis also revealed a progressive transformation of sub-grain boundaries into high angle grain boundaries. A multimechanism of dynamic recovery, continuous DRX and discontinuous DRX seems to be operating during the process. The microstructure is not affected by changing the rotation speed from 640 to 800 rev min
−1
, except that the grain size was marginally larger for higher rotational speed.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Ni particles were incorporated in a 5083 Al alloy matrix by friction stir processing (FSP) to fabricate metal particle reinforced composite. During the optimization of the process parameters for ...uniform particle distribution, it was found that ball-milled finer particles (10μm) were dispersed more uniformly in the matrix compared to as-received coarse particles (70μm). Hence, the particles were ball-milled before incorporating into 5083 Al matrix. The finer ball-milled particles were dispersed uniformly, however a thin intermetallic layer was formed at the particle-matrix interface. The layer was found to be Al–Ni intermetallic. When as-received fine particles of similar size (10μm) were incorporated using the same FSP parameters no such layer was observed in the processed composite. Hence, ball milling of particles influenced the microstructure of the composite. The high-energy state of the ball-milled particles can be attributed to the formation of the interfacial layer. The strength of both the composite was higher compared to the unreinforced 5083 Al alloy. FSP also refined the grain size of the aluminum matrix from 25µm to 3.5µm and this also contributed to the strength enhancement of the composites. The strength and ductility of the ball-milled composite were lower as expected compared to the composite with as-received fine Ni particles due to the presence of the interfacial reaction layer.
Background: A major impediment in treatment for cancers is resistance to chemotherapy and is primarily attributed to over-expression of efflux pumps. This study aimed to establish the cytotoxicity of ...malabaricone-A (MAL-A) in P-glycoprotein/multidrug resistance (P-gp/MDR) over-expressing hematopoietic cancer cell lines.Methods: Leukemia and multiple myeloma cell lines were indirectly evaluated for their P-gp/MDR status by examining Calcein-AM fluorescence and cell viability was assessed by the MTS-PMS assay.Results: The fluorescence of calcein was significantly decreased in three cell lines LP-1, RPMI-8226 and CEM-ADR 5000 and reversal with verapamil endorsed their P-gp/MDR activity. The mean IC50 of MAL-A in these MDR+ cell lines (5.40±1.41 to 12.33±0.78 µg/ml) was comparable with the MDR- leukemic (9.72±1.08 to 19.26±0.75 µg/ml) and multiple myeloma cell lines (9.65±0.39 to 18.05±0.17 μg/ml).Conclusions: Irrespective of their P-gp activity, the cytotoxicity of MAL-A was comparable, making it worthy of future pharmacological consideration in multidrug resistance.
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