Azole resistance is an emerging problem in Aspergillus which impacts the management of aspergillosis. Here in we report the emergence and clonal spread of resistance to triazoles in environmental ...Aspergillus fumigatus isolates in India. A total of 44 (7%) A. fumigatus isolates from 24 environmental samples were found to be triazole resistant. The isolation rate of resistant A. fumigatus was highest (33%) from soil of tea gardens followed by soil from flower pots of the hospital garden (20%), soil beneath cotton trees (20%), rice paddy fields (12.3%), air samples of hospital wards (7.6%) and from soil admixed with bird droppings (3.8%). These strains showed cross-resistance to voriconazole, posaconazole, itraconazole and to six triazole fungicides used extensively in agriculture. Our analyses identified that all triazole-resistant strains from India shared the same TR(34)/L98H mutation in the cyp51 gene. In contrast to the genetic uniformity of azole-resistant strains the azole-susceptible isolates from patients and environments in India were genetically very diverse. All nine loci were highly polymorphic in populations of azole-susceptible isolates from both clinical and environmental samples. Furthermore, all Indian environmental and clinical azole resistant isolates shared the same multilocus microsatellite genotype not found in any other analyzed samples, either from within India or from the Netherlands, France, Germany or China. Our population genetic analyses suggest that the Indian azole-resistant A. fumigatus genotype was likely an extremely adaptive recombinant progeny derived from a cross between an azole-resistant strain migrated from outside of India and a native azole-susceptible strain from within India, followed by mutation and then rapid dispersal through many parts of India. Our results are consistent with the hypothesis that exposure of A. fumigatus to azole fungicides in the environment causes cross-resistance to medical triazoles. The study emphasises the need of continued surveillance of resistance in environmental and clinical A. fumigatus strains.
Azole resistance in Aspergillus fumigatus isolates impacts on the management of aspergillosis since azoles are primary agents used for prophylaxis and therapy. We report the emergence of resistance ...to triazoles in two A. fumigatus isolates from patients in Delhi, India.
One hundred and three A. fumigatus isolates, collected from 85 patients suspected of bronchopulmonary aspergillosis during 2005-10, were investigated for susceptibility to itraconazole, voriconazole, posaconazole and isavuconazole. We undertook a mixed-format real-time PCR assay for the detection of mutations leading to triazole resistance in A. fumigatus. The resistant isolates were compared with 25 Dutch TR/L98H-positive isolates by microsatellite analysis.
Of the 103 A. fumigatus isolates tested, only 2 had high MIC values of itraconazole (>16 mg/L), voriconazole (2 mg/L), posaconazole (2 mg/L) and isavuconazole (8 mg/L). The resistant A. fumigatus isolates exhibited the TR/L98H genotype and showed identical patterns by microsatellite typing, but were different from 25 Dutch TR/L98H isolates.
We report for the first time from India the occurrence of TR/L98H mutations in the cyp51A gene (responsible for reduced azole susceptibility) in two A. fumigatus isolates from patients with chronic respiratory disease who had not previously been exposed to azoles. The presence of TR/L98H is consistent with a route of resistance development through exposure to azole compounds in the environment. Given the emergence of azole resistance in environmental strains, continued surveillance of resistance in clinical A. fumigatus strains is desirable for successful therapy of aspergillosis.
Abstract
A new multisensor (i.e. resistive and magnetic) CrI
3
-WTe
2
heterostructure (HS) to detect the toxic gases BrF
3
and COCl
2
(Phosgene) has been theoretically studied in our present ...investigation. The HS has demonstrated sensitivity towards both the gases by varying its electronic and magnetic properties when gas molecule interacts with the HS. Fast recovery time (<0.14
fs
) under UV radiation has been observed. We have considered two configurations of BrF
3
adsorbed HS; (1) when F ion interacts with HS (C1) and (2) when Br ion interacts with HS (C2). In C1 case the adsorption energy
E
ad
is observed to be −0.66 eV while in C2 it is −0.95 eV. On the other hand in case of COCl
2
E
ad
is found to be −0.42 eV. Magnetic moments of atoms are also found to vary upon gas adsorption indicates the suitability of the HS as a magnetic gas sensor. Our observations suggest the suitability of CrI
3
-WTe
2
HS to respond detection of the toxic gases like BrF
3
and COCl
2
.
A variety of theoretical and experimental works have reported several potential applications of MoS2 monolayer based heterostructures (HSs) such as light emitting diodes, photodetectors and field ...effect transistors etc. In the present work, we have theoretically performed as a model case study, MoS2 monolayer deposited over insulating SrTiO3 (001) to study the band alignment at TiO2 termination. The interfacial characteristics are found to be highly dependent on the interface termination. With an insulating oxide material, a significant band gap (0.85eV) is found in MoS2/TiO2 interface heterostructure (HS). A unique electronic band profile with an indirect band gap (0.67eV) is observed in MoS2 monolayer when confined in a cubic environment of SrTiO3 (STO). Adsorption analysis showed the chemisorption of MoS2 on the surface of STO substrate with TiO2 termination which is justified by the charge density calculations that shows the existence of covalent bonding at the interface. The fabrication of HS of such materials paves the path for developing the unprecedented 2D materials with exciting properties such as semiconducting devices, thermoelectric and optoelectronic applications.
Abstract
A variety of theoretical and experimental works have reported several potential applications of
MoS
2
monolayer based heterostructures (HSs) such as light emitting diodes, photodetectors and ...field effect transistors etc. In the present work, we have theoretically performed as a model case study,
MoS
2
monolayer deposited over insulating
SrTiO
3
(001) to study the band alignment at
TiO
2
termination. The interfacial characteristics are found to be highly dependent on the interface termination. With an insulating oxide material, a significant band gap (0.85eV) is found in MoS
2
/TiO
2
interface heterostructure (HS). A unique electronic band profile with an indirect band gap (0.67eV) is observed in
MoS
2
monolayer when confined in a cubic environment of
SrTiO
3
(STO). Adsorption analysis showed the chemisorption of
MoS
2
on the surface of STO substrate with
TiO
2
termination which is justified by the charge density calculations that shows the existence of covalent bonding at the interface. The fabrication of HS of such materials paves the path for developing the unprecedented 2D materials with exciting properties such as semiconducting devices, thermoelectric and optoelectronic applications.
A
bstract
The next generation electron-positron colliders are designed for precision studies of the Standard Model and its extensions, in particular in the Higgs sector. We consider the potential for ...discovery of composite Higgs models in Higgs pair production through photon collisions. This process is loop-generated, thus it provides access to all Higgs couplings and can show new physics effects in polarized and unpolarized cross-sections starting at relatively low collider energies. It is, therefore, relevant for all electron-positron colliders planned or in preparation. Sizeable deviations from the Standard Model predictions are present in a general class of composite Higgs models, as couplings of one or more Higgs bosons to fermions, or fermionic and scalar resonances, modify the destructive interference present in the Standard Model. In particular, large effects are due to the new quartic coupling of the Higgs to tops and to the presence of a light scalar resonance.
In this paper we present uniformly distributed ~100 nm BiFeO
3
nanoparticles synthesized by conventional chemical co-precipitation method in order to scrutinize structural, optical, photoluminescence ...and dielectric properties. The Rietveld refinement of the X-ray diffraction pattern revealed that the sample is single phase in nature and crystallizes in rhombohedral structure with
R3c
space group. The average crystallite size and particle strain were estimated by using Debye–Scherer’s and Hall–Williamson method. The particle size of the BiFeO
3
nanoparticles is ~100 nm with uniform size distribution predicted by the field-emission scanning electron micrographs. The effective band-gap of the nanostructures calculated as 2.74 eV along with additional defect levels determined by plotting Tauc relation. The Photoluminescence response of BiFeO
3
nanoparticles is extensively observed across the UV–Visible spectrum by illuminating the sample with different excitation wavelengths from ~280 to ~360 nm. Photoluminescence also specifies the characteristic band-gap of crystalline BiFeO
3
~2.96 eV, along with some prominent energy levels near the conduction and valence band edge that may appear due to nano-structuring. The chemical bonds between the constituent elements of the specimen are traced with FTIR spectroscopy. The dielectric study identifies low frequency dispersive nature of the specimen.
In this study, we successfully synthesized the multifunctional Tetragonal-Tungsten Bronze (TTB) compound, Ba
4
Bi
2
Fe
2
Nb
8
O
30
(BBFNO), using a planetary ball-milling approach. Our investigation ...comprehensively spanned structural, vibrational, ferroelectric, optical, and photoluminescence characteristics. Phase purity was rigorously confirmed through Rietveld-fitted X-ray powder diffraction and Fourier-transform infrared spectroscopy (FTIR), unveiling single-phase crystals within a tetragonal structure in the P4bm space group. Notably, electron density plots revealed concentrated charges on the heavier atoms. Moreover, employing the Williamson-Hall method, we established the average crystallite size as 171.53 nm. Vibrational aspects were explored through Raman spectroscopy, while a dedicated polarization study validated the presence of ferroelectric properties. UV–Vis spectroscopy allowed us to pinpoint an optical bandgap of 3.07 eV using Tauc's plot. Further analysis of photoluminescence exposed the role of oxygen vacancies in influencing energy band gap shifts towards the visible spectrum, thereby affecting electronic transitions. Importantly, the CIE (Commission Internationale de l’e´clairage) chromaticity coordinates of BBFNO fell within the bluish-violet range, suggesting potential applications in optical and display technologies. The remarkable multi-functionality of BBFNO underscores its substantial promise for diverse technological applications.
In this study, complex BiMn
2
O
5
(BMO) nanoparticles, well known for their applications in photocatalysts, magnetoelectric sensors, actuators, non-volatile information storages, and electrochemical ...supercapacitors, were synthesized through novel ultrasonication assisted sol–gel synthesis route. The corresponding Rietveld refinement confirms the monophasic nature of composition in Pbam space-group symmetry with orthorhombic structure. The morphological study examines the average grain size determined to be approximately around ∼ 64.50 nm, whereas, EDAX gives the elemental analysis. The vibrational modes of Mn–O and presence of other functional groups have been explored. The coexistence of the multivalency in Mn
4+
and Mn
3+
valence states, which are associated with the chemical stoichiometry of the synthesized compound is confirmed. The optimization of energy band-gap was attributed to influence the disordered crystal lattice and oxygen vacancies. The interesting Photoluminescence response of BiMn
2
O
5
NPs in visible region indicates strong purple-blue emission under excitation wavelength
λ
ex
~ 370 nm and CIE parameters. BMO nanoparticles have been evaluated as a photocatalyst for the decomposition of Rhodamine B dye under visible light illumination because of their low bandgap. In contrast, the presence of smaller nanoparticles and uncompensated spins depict M-H plot shows no saturation at high magnetic field, which manifest non-ferromagnetic correlation. The thermomagnetic study in field-cooled/zero-field-cooled modes also indicates an antiferromagnetic Neel transition at around 41 K. The results obtained from measurements and associated properties of nanoparticles give an insight of BiMn
2
O
5
nanoparticles for possible applications.
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