Catalytic N-oxidation of tertiary amines on RuO(2)NPs anchored graphene nanoplatelets

Ultrafine ruthenium oxide nanoparticles (RuO2NPs) with an average diameter of 1.3 nm were anchored on graphene nanoplatelets (GNPs) using a Ru(acac)3 precursor by a very simple dry synthesis method. The resultant material (GNPs–RuO2NPs) was used as a heterogeneous catalyst for the N-oxidation of tertiary amines for the first time. The transmission electron microscopy (TEM) images of the GNPs–RuO2NPs showed the excellent attachment of RuO2NPs on GNPs. The loading of Ru in GNPs–RuO2NPs was 2.68 wt%, as confirmed by scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). The X-ray photoelectron spectrum (XPS) and the X-ray diffraction pattern (XRD) of GNPs–RuO2NPs revealed that the chemical state of Ru on GNPs was +4. After the optimization of reaction conditions for N-oxidation of triethylamine, the scope of the reaction was extended to various aliphatic, alicyclic and aromatic tertiary amines. The GNPs–RuO2NPs showed excellent catalytic activity in terms of yields even at a very low amount of Ru catalyst (0.13 mol%). The GNPs–RuO2NPs was heterogeneous in nature, chemically as well as physically, very stable and could be reused up to 5 times.ArticleCATALYSIS SCIENCE & TECHNOLOGY. 4(7):2099-2106 (2014)journal articl

Photodegradation of dyes by a novel TiO2/u-RuO2/GNS nanocatalyst derived from Ru/GNS after its use as catalyst in aerial oxidation of primary alcohols (GNS = Graphene NanoSheets)

Ruthenium nanoparticles (RuNPs) supported on graphene nanosheets (GNS), a composite (Ru/GNS), were prepared by a dry synthesis method and were used as nanocatalysts for the aerial oxidation of various primary alcohols. Ru/GNS was highly efficient, selective, stable and heterogeneous in nature. Owing to the high stability of the used catalyst (u-Ru/GNS), it was further applied in a different catalytic system viz photocatalytic degradation, after suitable modifications. We have obtained a novel TiO2/u-RuO2/GNS catalyst from u-Ru/GNS by the sol-gel method. The catalytic activity of TiO2/u-RuO2/GNS toward the photodegradation of methyl orange (MO) and acridine orange (AO) was found to be excellent. Overall, the sustainable use of these recyclable materials (Ru/GNS and TiO2/u-RuO2/GNS) could lead to economic and environmental benefits.Reaction Kinetics, Mechanisms and Catalysis. 115(2):759-772 (2015)journal articl

Screening of recombinant inbred lines for resistance to bacterial leaf blight pathotypes in rice (Oryza sativa L.)

In the present investigation 16 recombinant inbred lines (RIL’s) developed from the intra-specific cross between YH3 and AKDRMS 21-54 through Marker Assisted Pedigree Breeding Method were screened along with their parents and the checks, namely, BPT 5204, TN1 and Improved Samba Mahsuri (ISM) against IxoPt-20 pathotype at the ICAR-Indian Institute of Rice Research, Hyderabad during Rabi 2021-22 and a new pathotype of Xanthomonas oryzae pv. oryzae causing Bacterial Leaf Blight disease in rice at Regional Agricultural Research Station, Maruteru during Kharif 2022 to identify pathotype specific resistant sources.  Morpho-Molecular screening was adopted to evaluate the recombinant inbred lines over two locations in the consecutive seasons of Rabi 2021-22 and Kharif 2022. Based on per cent diseased leaf area, the genotypes were scored and categorised as per the Standard Evaluation System (SES) scale provided by International Rice Research Institute (IRRI). The results revealed all 16 RIL’s to be either resistant (10) or moderately resistant (6) to IxoPt-20 pathotype. However, only five RIL’s were found to be resistant, while four RIL’s were moderately resistant for the new virulent pathotype. Seven RIL’s with resistant to moderately resistant reaction for IxoPt-20 pathotype, showed moderately susceptible reaction for the new virulent pathotype.  Among the resistant RIL’s identified for each pathotype, BPT-1901-72-10-6, BPT-1901-108-4-1 and BPT-1901-111-3-2 were found to be uniformly resistant, while, BPT-1901-45-8-6 and BPT-1901-163-1-18 were uniformly moderately resistant to both IXoPt-20 and the new virulent pathotype at Hyderabad and Maruteru, respectively, indicating their potential as genetic stocks for development of new cultivars resistant to bacterial leaf blight disease

Wave-packet dynamics in slowly perturbed crystals: Gradient corrections and Berry-phase effects

We present a unified theory for wave-packet dynamics of electrons in crystals subject to perturbations varying slowly in space and time. We derive the wave-packet energy up to the first order gradient correction and obtain all kinds of Berry-phase terms for the semiclassical dynamics and the quantization rule. For electromagnetic perturbations, we recover the orbital magnetization energy and the anomalous velocity purely within a single-band picture without invoking inter-band couplings. For deformations in crystals, besides a deformation potential, we obtain a Berry-phase term in the Lagrangian due to lattice tracking, which gives rise to new terms in the expressions for the wave-packet velocity and the semiclassical force. For multiple-valued displacement fields surrounding dislocations, this term manifests as a Berry phase, which we show to be proportional to the Burgers vector around each dislocation.Comment: 12 pages, RevTe

Role of matrix metalloproteinases in multi-system inflammatory syndrome and acute COVID-19 in children

INTRODUCTION: Multisystem Inflammatory Syndrome in children (MIS-C) is a serious inflammatory sequela of SARS-CoV2 infection. The pathogenesis of MIS-C is vague and matrix metalloproteinases (MMPs) may have an important role. Matrix metalloproteinases (MMPs) are known drivers of lung pathology in many diseases. METHODS: To elucidate the role of MMPs in pathogenesis of pediatric COVID-19, we examined their plasma levels in MIS-C and acute COVID-19 children and compared them to convalescent COVID-19 and children with other common tropical diseases (with overlapping clinical manifestations). RESULTS: Children with MIS-C had elevated levels of MMPs (P < 0.005 statistically significant) in comparison to acute COVID-19, other tropical diseases (Dengue fever, typhoid fever, and scrub typhus fever) and convalescent COVID-19 children. PCA and ROC analysis (sensitivity 84–100% and specificity 80–100%) showed that MMP-8, 12, 13 could help distinguish MIS-C from acute COVID-19 and other tropical diseases with high sensitivity and specificity. Among MIS-C children, elevated levels of MMPs were seen in children requiring intensive care unit admission as compared to children not needing intensive care. Similar findings were noted when children with severe/moderate COVID-19 were compared to children with mild COVID-19. Finally, MMP levels exhibited significant correlation with laboratory parameters, including lymphocyte counts, CRP, D-dimer, Ferritin and Sodium levels. DISCUSSION: Our findings suggest that MMPs play a pivotal role in the pathogenesis of MIS-C and COVID-19 in children and may help distinguish MIS-C from other conditions with overlapping clinical presentation

Unique cellular immune signatures of multisystem inflammatory syndrome in children

The clinical presentation of MIS-C overlaps with other infectious/non-infectious diseases such as acute COVID-19, Kawasaki disease, acute dengue, enteric fever, and systemic lupus erythematosus. We examined the ex-vivo cellular parameters with the aim of distinguishing MIS-C from other syndromes with overlapping clinical presentations. MIS-C children differed from children with non-MIS-C conditions by having increased numbers of naïve CD8(+) T cells, naïve, immature and atypical memory B cells and diminished numbers of transitional memory, stem cell memory, central and effector memory CD4(+) and CD8(+) T cells, classical, activated memory B and plasma cells and monocyte (intermediate and non-classical) and dendritic cell (plasmacytoid and myeloid) subsets. All of the above alterations were significantly reversed at 6–9 months post-recovery in MIS-C. Thus, MIS-C is characterized by a distinct cellular signature that distinguishes it from other syndromes with overlapping clinical presentations. Trial Registration: ClinicalTrials.gov clinicaltrial.gov. No: NCT04844242