Interface enriched highly interlaced layered MoS2/NiS2 nanocomposites for the photocatalytic degradation of rhodamine B dye

In the past few decades, air and water pollution by organic dyes has become a serious concern due to their high toxicity. Removal of these organic dyes from polluted water bodies is a serious environmental concern and the development of new advanced photocatalytic materials for decomposing organic dyes can be a good solution. In this work, layered molybdenum disulfide/nickel disulfide (MoS2/NiS2) nanocomposites with various NiS2 content was synthesized by a one-step hydrothermal method using citric acid as a reducing agent. The X-ray diffraction pattern shows the hexagonal and cubical crystal structure of MoS2 and NiS2, respectively. Morphological analysis confirms the formation of MoS2/NiS2 nanosheets. The elemental composition of the samples was carried out by XPS, which shows a significant interaction between NiS2 and MoS2. The photocatalytic performance of MoS2/NiS2 nanocomposites was studied by the degradation of rhodamine B (RhB). Ni-4 sample shows higher photocatalytic activity with a maximum degradation of 90.61% under visible light irradiation for 32 min.

Engineering new limits to magnetostriction through metastability in iron-gallium alloys

Magnetostrictive materials transduce magnetic and mechanical energies and when combined with piezoelectric elements, evoke magnetoelectric transduction for high-sensitivity magnetic field sensors and energy-efficient beyond-CMOS technologies. The dearth of ductile, rare-earth-free materials with high magnetostrictive coefficients motivates the discovery of superior materials. Fe_1-xGa_x alloys are amongst the highest performing rare-earth-free magnetostrictive materials; however, magnetostriction becomes sharply suppressed beyond x = 19% due to the formation of a parasitic ordered intermetallic phase. Here, we harness epitaxy to extend the stability of the BCC Fe_1-xGa_x alloy to gallium compositions as high as x = 30% and in so doing dramatically boost the magnetostriction by as much as 10x relative to the bulk and 2x larger than canonical rare-earth based magnetostrictors. A Fe_1-xGa_x - [Pb(Mg_1/3Nb_2/3)O₃]_0.7-[PbTiO₃]_0.3 (PMN-PT) composite magnetoelectric shows robust 90° electrical switching of magnetic anisotropy and a converse magnetoelectric coefficient of 2.0 × 10^-5 s m^-1. When optimally scaled, this high coefficient implies stable switching at ~80 aJ per bit.

Assessment of biogrowth assemblages with depth in a seawater intake system of a coastal power station

Marine biogrowth infestation of a seawater intake system was investigated. A digital camera fixed onto a skid was used to record the biogrowth at intervals of 5 m up to a depth of 55 m. Divers inspected the intake shaft and collected the biogrowth samples for biomass estimation. A biomass density of 7.5 kg m^-2 and 28.2 kg m^-2 was recorded at 5 and 30 m depths respectively. Inspection by the divers revealed that hard-shelled organisms such as oysters and brown and green mussels were observed in plenty up to a thickness of 15 cm and bryozoans grew as epibionts. At lower depths (<40 m), hydroids grew on the shells of green mussels along with silt accumulation. The biofouling community was composed of 46 organisms, exhibiting variation in distribution and abundance. The study explains the extent and type of marine biogrowth phenomena with depth and describes biofouling preventive methods.Supplemental data for this article is available online at https://doi.org/10.1080/08927014.2021.1933457 .

Triple-negative breast cancers with expression of glucocorticoid receptor in immune cells show better prognosis

Background

Glucocorticoid receptor (GR) is shown to have variable frequency of expression in invasive tumors of the breast. Investigation of additional nuclear receptors like GR in receptor negative tumors like triple negative breast cancer (TNBC) may have prognostic and therapeutic significance.

Methods

Expression of GR was evaluated by immunohistochemistry in 175 tumors of invasive breast cancer with long term follow up. GR Expression was separately evaluated in invasive tumor cells, stromal cells and tumor infiltrating lymphocytes (TIL's). Staining pattern was categorised as positive when more than 1% of the cells stained in each subpopulation of cells. Disease free survival was analysed between GR positive and negative status by Kaplan Meier analysis.

Results

Of the 175 tumors, 121 (70%) were ER positive, 53 (30%) were ER negative and 29% (51) were triple negative. 74% (130/175) tumors showed expression of GR in invasive tumor cells while (84%) 147/175 had expression in TIL's. No significant difference in distribution of GR was noted between ER positive and ER negative tumors (78% vs 66%, p-0.1). Of the TNBC's 54% (28/51) and 70% (36/51) showed expression of GR in invasive tumor and TIL's respectively. Overall, GR positive tumors had significant better survival than GR negative tumors (mean survival time of 85 vs 59 months respectively, p-0.04) Contrary to the reports that GR expression in TIL's are associated with immunosuppressive activity in model systems, TNBC's with increased expression of GR in immune cells were associated with better survival (Mean survival time 74 vs 41 months, log rank test- p-0.03). TNBC tumors which were GR negative had higher lymph node metastases (p-0.04) and none of the other clinical features like age, menopausal state, tumor size and grade were different between GR positive and negative tumors within TNBC.

Conclusions

Glucocorticoids (GC) are often used to alleviate the adverse symptoms during chemotherapy. Determining the GR status is of importance due to the pro cell survival effect of the glucocorticoids mediated through GR during chemotherapy. Though GC mediated effects on chemotherapy are controversial, our results indicate favourable effects in TNBC.

Vortex Domain Walls in Ferroelectrics

Controlling the domain formation in ferroelectric materials at the nanoscale is a fertile ground to explore emergent phenomena and their technological prospects. For example, charged ferroelectric domain walls in BiFeO₃ and ErMnO₃ exhibit significantly enhanced conductivity which could serve as the foundation for next-generation circuits (Estévez and Laurson, Phys. Rev. B 2015, 91, 054407). Here, we describe a concept in which polar vortices perform the same role as a ferroelectric domain wall in classical domain structures with the key difference being that the polar vortices can accommodate charged (i.e., head-to-head and tail-to-tail) domains, for example, in ferroelectric PbTiO₃/dielectric SrTiO₃ superlattices. Such a vortex domain wall structure can be manipulated in a reversible fashion under an external applied field.

The construction of a dual direct Z-scheme NiAl LDH/g-C3N4/Ag3PO4 nanocomposite for enhanced photocatalytic oxygen and hydrogen evolution

Dual direct Z-scheme photocatalysts for overall water decomposition have demonstrated strong redox abilities and the efficient separation of photogenerated electron-hole pairs. Overall water splitting utilizing NiAl-LDH-based binary and ternary nanocomposites has been extensively investigated. The synthesized binary and ternary nanocomposites were characterized via XRD, FTIR, SEM, HRTEM, XPS, UV-DRS, and photoelectrochemical measurements. The surface wettability properties of the prepared nanocomposites were measured via contact angle measurements. The application of the NiAl-LDH/g-C3N4/Ag3PO4 ternary nanocomposite was investigated for photocatalytic overall water splitting under light irradiation. In this work, we found that in the presence of Ag3PO4, the evolution of H2 and O2 is high over LCN30, and 2.8- fold (O2) and 1.4-fold (H2) activity increases can be obtained compared with the use of LCN30 alone. It is proposed that Ag3PO4 is involved in the O2 evolution reaction during water oxidation and g-C3N4 is involved in overall water splitting. Our work not only reports overall water splitting using NiAl-LDH-based nanocomposites but it also provides experimental evidence for understanding the possible reaction process and the mechanism of photocatalytic water splitting. Photoelectrochemical measurements confirmed the better H2 and O2 evolution abilities of NiAl-LDH/g-C3N4/Ag3PO4 in comparison with NiAl LDH, g-C3N4, Ag3PO4, and LCN30. The observed improvement in the gas evolution properties of NiAl LDH in the presence of Ag3PO4 is due to the formation of a dual direct Z-scheme, which allows for the easier and faster separation of charge carriers. More importantly, the LCNAP5 heterostructure shows high levels of H2 and O2 evolution, which are significantly enhanced compared with LCN30 and pure NiAl LDH.

Aggregation of Region-based and Boundary-based Knowledge Biased Segmentation for Osteoporosis Detection from X-Ray, Dual X-Ray and CT Images

BACKGROUND

Osteoporosis is a term used to represent the reduced bone density, which is caused by insufficient bone tissue production to balance the old bone tissue removal. Medical Imaging procedures such as X-Ray, Dual X-Ray and Computed Tomography (CT) scans are used widely in osteoporosis diagnosis. There are several existing procedures in practice to assist osteoporosis diagnosis, which can operate using a single imaging method.

OBJECTIVE

The purpose of this proposed work is to introduce a framework to assist the diagnosis of osteoporosis based on consenting all these X-Ray, Dual X-Ray and CT scan imaging techniques. The proposed work named "Aggregation of Region-based and Boundary-based Knowledge biased Segmentation for Osteoporosis Detection from X-Ray, Dual X-Ray and CT images" (ARBKSOD) is the integration of three functional modules.

METHODS

Fuzzy Histogram Medical Image Classifier (FHMIC), Log-Gabor Transform based ANN Training for osteoporosis detection (LGTAT) and Knowledge biased Osteoporosis Analyzer (KOA).

RESULTS

Together, all these three modules make the proposed method ARBKSOD scored the maximum accuracy of 93.11%, the highest precision value of 93.91% while processing the 6th image batch, the highest sensitivity of 92.93%, the highest specificity of 93.79% is observed during the experiment by ARBKSOD while processing the 6th image batch. The best average processing time of 10244 mS is achieved by ARBKSOD while processing the 7th image batch.

CONCLUSION

Together, all these three modules make the proposed method ARBKSOD to produce a better result.

A comprehensive in silico and in vitro studies on quinizarin: a promising phytochemical derived from Rhizophora mucronata Lam

Mangrove plants are a great source of phytomedicines, since from the beginning of human civilization and the origin of traditional medicines. In the present study, ten different mangrove leaf methanolic extracts were screened for the type of phytochemicals followed by assessing antimicrobial, anti-oxidant and anti-cancer activities. The efficient methanolic crude extract of Rhizospora mucornata was further purified and characterized for the presence of the bioactive compound. Based on UV-visible spectroscopy, FTIR, NMR and HRMS analysis, the bioactive compound was 1,4-dihydroanthraquinone; also termed as Quinizarin. This identified compound was potential in exhibiting antimicrobial, antioxidant, and cytotoxic activity. Quinizarin inhibited the growth of Bacillus cereus and Klebsiella aerogenes with minimum inhibitory concentration (MIC) of 0.78 and 1.5 mg/ml. The DPPH free radical scavenging assay revealed the maximum activity of 99.8% at the concentration of 200 µg/ml with an IC50 value of 12.67 ± 0.41 µg/ml. Cytotoxic assay against HeLa (cervical) and MDA-MB231(breast) cancer cell lines revealed IC50 values to be 4.60 ± 0.26 and 3.89 ± 0.15 µg/ml. Together the results of molecular docking and molecular dynamics simulation studies explained that Quinizarin molecule showed stronger binding affinity (-6.2 kcal/mol) and significant structural stability towards anti-apoptotic Bcl-2 protein. Thus, the study put forth the promising role of the natural molecule - Quinizarin isolated from R. mucornata in the formulation of therapeutic drugs against bacterial infections and cancer. Communicated by Ramaswamy H. Sarma.

First report of rhizome rot of banana caused by Klebsiella variicola in India

Rhizome rot or soft rot disease is one of the major problems in banana (Musa spp.) cultivation, as it causes germination failure and death of early stage plants. A roving survey conducted during 2017 to 2019 in the major banana growing states of India indicated a 5-30% incidence of rhizome rot in commercial cultivars. The symptoms observed were yellowing of leaves, necrotic drying with or without heart rot, and yellow or brown water soaked spots with dark brown margins in the rhizomes. Decay of tissues, cavity formation and brown ooze with foul smell, and toppling were also observed. To isolate bacteria, dissected diseased tissues were surface sterilized and plated on Crystal Violet Pectate (CVP) medium. Of 60 samples plated on CVP medium, three samples collected from cvs. NeyPoovan-AB (Karur, Tamil Nadu, 10°56'36.8"N;78°24'12.5"E), Grand Naine-AAA (Tiruchirappalli, Tamil Nadu, 10°47'26.1"N;78°34'14.8"E) and Thellachakkarakeli-AAA (East-Godavari, Andhra Pradesh, 16°51'32.1"N;81°46'08.4"E), did not yield any bacteria; however, when plated on nutrient agar, they produced whitish to dull white, mucoid, raised, round and translucent colonies, and three isolates were named as NPK-3-48, GTC-5 and 1-1B-3, respectively. Because these colonies were distinct from colonies obtained on CVP medium (which were analyzed and confirmed separately as Pectobaterium sp.) (Gokul et al. 2019), they were further characterized. Amplification of 16S rDNA genes of NPK-3-48, GTC-5 and 1-1B-3 isolates using universal primers (27F 5' - AGAGTTTGATCCTGGCTCAG - 3'; 1492 R 5' - GGTTACCTTGTTACGACTT - 3') and rpoB gene (Rosenblueth et al. 2004) was carried; the amplicons were sequenced and deposited in NCBI (Accessions MW036529-MW036531; MW497572-MW497574). Phylogenetic analysis of rpoB clearly showed that the isolates NPK-3-48, GTC-5, 1-1B-3 are Klebsiella variicola (Rosenblueth et al. 2004) Besides, biochemical tests also indicated that all three isolates were Gram negative, catalase positive, oxidase negative and able to utilize glucose, maltose and citrate (Ajayasree and Borkar 2018). Therefore, the above said morphological, molecular and biochemical analyses carried out indicated that NPK-3-48, GTC-5, 1-1B-3 are of K. variicola. Earlier, K. variicola causing soft rot has been reported on banana in China (Fan et al. 2016), plantain soft rot in Haiti (Fulton et al. 2020) and carrot soft rot in India (Chandrashekar et al. 2018). For pathogenicity tests, these three isolates were grown in nutrient broth for 48 h at 37±1°C and the cells were harvested by centrifugation. Five milliliters of the culture suspension (2×108 CFUmL-1) taken in a syringe was injected into rhizomes of three month old tissue cultured Grand Naine plants. Each bacterial isolate was injected into eight banana plants at soil level. Appropriate controls were maintained. Inoculated plants were maintained in a glasshouse at 32±2°C and after 30-35 days, rhizome rot symptoms appeared in all the three bacterial isolates inoculated plants but in none of the control plants. The Koch's postulates were proved by re-isolation and identification.To the best of our knowledge, this is the first report of K. variicola causing rhizome rot disease of banana in India.

Coherent electric field manipulation of Fe3+ spins in PbTiO3

Magnetoelectrics, materials that exhibit coupling between magnetic and electric degrees of freedom, not only offer a rich environment for studying the fundamental materials physics of spin-charge coupling but also present opportunities for future information technology paradigms. We present results of electric field manipulation of spins in a ferroelectric medium using dilute ferric ion-doped lead titanate as a model system. Combining first-principles calculations and electron paramagnetic resonance (EPR), we show that the ferric ion spins are preferentially aligned perpendicular to the ferroelectric polar axis, which we can manipulate using an electric field. We also demonstrate coherent control of the phase of spin superpositions by applying electric field pulses during time-resolved EPR measurements. Our results suggest a new pathway toward the manipulation of spins for quantum and classical spintronics.

Epitaxial Ferroelectric Hf0.5 Zr0.5 O2 with Metallic Pyrochlore Oxide Electrodes

The synthesis of fully epitaxial ferroelectric Hf_0.5 Zr_0.5 O₂ (HZO) thin films through the use of a conducting pyrochlore oxide electrode that acts as a structural and chemical template is reported. Such pyrochlores, exemplified by Pb₂ Ir₂ O₇ (PIO) and Bi₂ Ru₂ O₇ (BRO), exhibit metallic conductivity with room-temperature resistivity of <1 mΩ cm and are closely lattice matched to yttria-stabilized zirconia substrates as well as the HZO layers grown on top of them. Evidence for epitaxy and domain formation is established with X-ray diffraction and scanning transmission electron microscopy, which show that the c-axis of the HZO film is normal to the substrate surface. The emergence of the non-polar-monoclinic phase from the polar-orthorhombic phase is observed when the HZO film thickness is ≥≈30 nm. Thermodynamic analyses reveal the role of epitaxial strain and surface energy in stabilizing the polar phase as well as its coexistence with the non-polar-monoclinic phase as a function of film thickness.

Local negative permittivity and topological phase transition in polar skyrmions

Topological solitons such as magnetic skyrmions have drawn attention as stable quasi-particle-like objects. The recent discovery of polar vortices and skyrmions in ferroelectric oxide superlattices has opened up new vistas to explore topology, emergent phenomena and approaches for manipulating such features with electric fields. Using macroscopic dielectric measurements, coupled with direct scanning convergent beam electron diffraction imaging on the atomic scale, theoretical phase-field simulations and second-principles calculations, we demonstrate that polar skyrmions in (PbTiO₃)_n/(SrTiO₃)_n superlattices are distinguished by a sheath of negative permittivity at the periphery of each skyrmion. This enhances the effective dielectric permittivity compared with the individual SrTiO₃ and PbTiO₃ layers. Moreover, the response of these topologically protected structures to electric field and temperature shows a reversible phase transition from the skyrmion state to a trivial uniform ferroelectric state, accompanied by large tunability of the dielectric permittivity. Pulsed switching measurements show a time-dependent evolution and recovery of the skyrmion state (and macroscopic dielectric response). The interrelationship between topological and dielectric properties presents an opportunity to simultaneously manipulate both by a single, and easily controlled, stimulus, the applied electric field.

Accumulation and ecotoxicological risk of weathered polyethylene (wPE) microplastics on green mussel (Perna viridis)

Recent studies have shown that organisms including humans are exposed to microplastics directly or indirectly. The present study aims to examine the ingestion of these microplastics and the consequences of the same by studying the accumulation behavior of weathered Polyethylene (wPE) microplastics. The Perna viridis were exposed chronically to three different environmentally relevant concentrations of wPE for 30 days, followed by a one-week depuration phase. There was no mortality observed in the control and exposed groups, but the feeding rate was observed to have substantially decreased in the group exposed to higher concentration (3 μgL^-1) of wPE. It was also observed that a higher number of wPE particles accumulated in the intestine of exposed organisms. Interestingly, the present study revealed the presence of the substantial number of wPE particles in exposed organisms, which may adversely affect the internal organs as well as growth and reproduction. This study perceived that accumulation is marginally influenced by size of wPE. Similarly, biomarker analysis showed that wPE exposure significantly altered both the metabolism and histology of the internal organs of the exposed organisms. Overall, the study confirmed that the intestine was the most sensitive organ followed by gills, adductor muscles, and foot tissue adding new insights into the adverse effects of wPE in the marine ecosystem.

Antiferromagnetic switching driven by the collective dynamics of a coexisting spin glass

The theory behind the electrical switching of antiferromagnets is premised on the existence of a well-defined broken symmetry state that can be rotated to encode information. A spin glass is, in many ways, the antithesis of this state, characterized by an ergodic landscape of nearly degenerate magnetic configurations, choosing to freeze into a distribution of these in a manner that is seemingly bereft of information. Here, we show that the coexistence of spin glass and antiferromagnetic order allows a novel mechanism to facilitate the switching of the antiferromagnet Fe_{1/3 + δ}NbS₂, rooted in the electrically stimulated collective winding of the spin glass. The local texture of the spin glass opens an anisotropic channel of interaction that can be used to rotate the equilibrium orientation of the antiferromagnetic state. Manipulating antiferromagnetic spin textures using a spin glass' collective dynamics opens the field of antiferromagnetic spintronics to new material platforms with complex magnetic textures.

Site-specific spectroscopic measurement of spin and charge in (LuFeO3)m/(LuFe2O4)1 multiferroic superlattices

Interface materials offer a means to achieve electrical control of ferrimagnetism at room temperature as was recently demonstrated in (LuFeO3)m/(LuFe2O4)1 superlattices. A challenge to understanding the inner workings of these complex magnetoelectric multiferroics is the multitude of distinct Fe centres and their associated environments. This is because macroscopic techniques characterize average responses rather than the role of individual iron centres. Here, we combine optical absorption, magnetic circular dichroism and first-principles calculations to uncover the origin of high-temperature magnetism in these superlattices and the charge-ordering pattern in the m = 3 member. In a significant conceptual advance, interface spectra establish how Lu-layer distortion selectively enhances the Fe2+ →  Fe3+ charge-transfer contribution in the spin-up channel, strengthens the exchange interactions and increases the Curie temperature. Comparison of predicted and measured spectra also identifies a non-polar charge ordering arrangement in the LuFe2O4 layer. This site-specific spectroscopic approach opens the door to understanding engineered materials with multiple metal centres and strong entanglement.

Electric-field control of spin dynamics during magnetic phase transitions

Controlling magnetization dynamics is imperative for developing ultrafast spintronics and tunable microwave devices. However, the previous research has demonstrated limited electric-field modulation of the effective magnetic damping, a parameter that governs the magnetization dynamics. Here, we propose an approach to manipulate the damping by using the large damping enhancement induced by the two-magnon scattering and a nonlocal spin relaxation process in which spin currents are resonantly transported from antiferromagnetic domains to ferromagnetic matrix in a mixed-phased metallic alloy FeRh. This damping enhancement in FeRh is sensitive to its fraction of antiferromagnetic and ferromagnetic phases, which can be dynamically tuned by electric fields through a strain-mediated magnetoelectric coupling. In a heterostructure of FeRh and piezoelectric PMN-PT, we demonstrated a more than 120% modulation of the effective damping by electric fields during the antiferromagnetic-to-ferromagnetic phase transition. Our results demonstrate an efficient approach to controlling the magnetization dynamics, thus enabling low-power tunable electronics.

Beyond Substrates: Strain Engineering of Ferroelectric Membranes

Strain engineering in perovskite oxides provides for dramatic control over material structure, phase, and properties, but is restricted by the discrete strain states produced by available high-quality substrates. Here, using the ferroelectric BaTiO₃ , production of precisely strain-engineered, substrate-released nanoscale membranes is demonstrated via an epitaxial lift-off process that allows the high crystalline quality of films grown on substrates to be replicated. In turn, fine structural tuning is achieved using interlayer stress in symmetric trilayer oxide-metal/ferroelectric/oxide-metal structures fabricated from the released membranes. In devices integrated on silicon, the interlayer stress provides deterministic control of ordering temperature (from 75 to 425 °C) and releasing the substrate clamping is shown to dramatically impact ferroelectric switching and domain dynamics (including reducing coercive fields to <10 kV cm^-1 and improving switching times to <5 ns for a 20 µm diameter capacitor in a 100-nm-thick film). In devices integrated on flexible polymers, enhanced room-temperature dielectric permittivity with large mechanical tunability (a 90% change upon ±0.1% strain application) is demonstrated. This approach paves the way toward the fabrication of ultrafast CMOS-compatible ferroelectric memories and ultrasensitive flexible nanosensor devices, and it may also be leveraged for the stabilization of novel phases and functionalities not achievable via direct epitaxial growth.

Toward Intrinsic Ferroelectric Switching in Multiferroic BiFeO_{3}

Using pulsed ferroelectric measurements, we probe switching dynamics in multiferroic BiFeO_{3}, revealing low-ns switching times and a clear pathway to sub-ns switching. Our data is well described by a nucleation and growth model, which accounts for the various timescales in the switching process, namely (1) the ferroelectric polarization switching (bound-charge) dynamics and (2) the RC-limited movement of free charge in the circuit. Our model shows good agreement with observed data and begins to bridge the gap between experiment and theory, indicating pathways to study ferroelectric switching on intrinsic timescales.

Ultralow Voltage Manipulation of Ferromagnetism

Spintronic elements based on spin transfer torque have emerged with potential for on-chip memory, but they suffer from large energy dissipation due to the large current densities required. In contrast, an electric-field-driven magneto-electric storage element can operate with capacitive displacement charge and potentially reach 1-10 µJ cm^-2 switching operation. Here, magneto-electric switching of a magnetoresistive element is shown, operating at or below 200 mV, with a pathway to get down to 100 mV. A combination of phase detuning is utilized via isovalent La substitution and thickness scaling in multiferroic BiFeO₃ to scale the switching energy density to ≈10 µJ cm^-2 . This work provides a template to achieve attojoule-class nonvolatile memories.

Defect-Enhanced Polarization Switching in the Improper Ferroelectric LuFeO3

Results of switching behavior of the improper ferroelectric LuFeO₃ are presented. Using a model set of films prepared under controlled chemical and growth-rate conditions, it is shown that defects can reduce the quasi-static switching voltage by up to 40% in qualitative agreement with first-principles calculations. Switching studies show that the coercive field has a stronger frequency dispersion for the improper ferroelectrics compared to a proper ferroelectric such as PbTiO₃ . It is concluded that the primary structural order parameter controls the switching dynamics of such improper ferroelectrics.