We reanalyze the decay constants of s-wave and p-wave mesons and the D, B → M form factors, where M represents a pseudoscalar meson, a vector meson, a scalar meson or an axial vector meson within a ...covariant light-front quark model. The parameter β for wavefunctions of most of s-wave mesons and that of a few axial-vector mesons are fixed with the latest experimental information, wherever available or using the lattice calculations. The treatment of masses and mixing angles for strange axial vector mesons is improved for the purpose. We extend our analysis to determine the form factors appearing in the Ds, Bs → M transitions, and to the isoscalar final state mesons. Numerical results of the form factors for transitions between a heavy pseudoscalar meson and an s-wave or a p-wave light meson and their momentum dependence are presented in detail. Further, their sensitivity to uncertainties of the β parameters of the initial as well as the final mesons is investigated. Some experimental measurements of the charmed and bottom meson decays are employed to compare the decay constants and transition form factors obtained in this and other works.
Abstract The excessive intake and inhalation of Triethylamine (TEA), which is an essential ingredient of pharmaceuticals, emulsifiers, dyestuff, soaps, rubber production etc, can cause health hazards ...such as blue haze, blurry vision, nausea, headache, and faintness; and to prevent the human beings from these hazards, it is crucial to detect TEA level. The present study explores the detection of TEA, using ZnO nanorods and porphyrin coated optical fiber probes. These probes have been synthesized and the topography, composition and morphology of different layers have been confirmed using FESEM, EDX and NMR characterizations. The sensitivity of this hybrid material-based probe has been estimated and was found to be 7-fold to the sensitivity of the metal oxide (ZnO nanorods) based fiber optic probe. The selectivity study has also been performed and it was observed that the analyte TEA has highest response (83.495 nm shift in peak wavelength) compared to other analytes such as the ethanol. This hybrid material-based fiber-optic probe offers the better selectivity and sensitivity for TEA and provides a very quick response time.
Diethanolamine (DEA) is used for amine wash to remove toxic gases such as hydrogen sulphide (H
2
S) while processing crude oil and in other pharmaceutical products. The detection of diethanolamine is ...of prime importance to avoid its harmful impact. In this study, we have designed a lossy mode resonance (LMR)-based optical fiber sensor for the detection of DEA. An optical fiber probe was fabricated by coating a bulk layer of titanium dioxide (TiO
2
) on the core of the optical fiber (probe-1). To extend this study, we prepared biosynthesised gold nanoparticles and coated them on to the top of the TiO
2
-layer-coated probe (probe-2). The surface structure was confirmed using characterization techniques such as FESEM, HRTEM and UV-visible spectroscopy. Further, a comparative study among probe-1 and probe-2 has been carried out in terms of their performance parameters such as sensitivity, figure of merit, limit of detection, repeatability and response time. The sensitivity of the TiO
2
bulk layer/AuNP bilayer-coated optical fiber probe (probe-2) was observed to be 16 079.63 nm RIU
−1
(0.074 nm mM
−1
), which was approximately double the sensitivity of the TiO
2
bulk layer-coated optical fiber probe (probe-1). Selectivity experiments were also performed to confirm the high sensitivity of the sensor towards DEA.
Diethanolamine (DEA) is used for amine wash to remove toxic gases such as hydrogen sulphide (H
2
S) while processing crude oil and in other pharmaceutical products.
•SPR based fiber optic sensor for adulteration detection in pure honey is presented.•Probes have been fabricated by utilizing silver and Ag-graphene oxide (GO) thin films.•GO modified probe enhances ...sensitivity to 24% and 37% for glucose and fructose adulterated honey.•Repeatability, Limit of Detection and Limit of Quantification has also been assessed.•Easy, rapid, label free technique for the detection of glucose/fructose in pure honey.
Fiber optic surface plasmon resonance (SPR) sensor utilizing silver (Ag) and Ag-graphene oxide (GO) is designed and developed for the detection of adulteration of glucose and fructose in pure honey. The concentration range of the two adulterants in pure honey is varied from 4% to 20% with a step change of 4%. The experiments were performed with two different fiber optic probes viz. Probe 1 and Probe 2. Probe 1 is fabricated by coating 50 nm Ag film on unclad optical fiber portion and Probe 2 is fabricated by modifying Ag film with GO for sensitivity improvement. The study confirms that using GO modified fiber optic probe, the sensitivity is enhanced to 24% and 37% for glucose and fructose adulterated honey samples respectively. The technique presented in this study is easy, rapid, label free and shows high prospective for the detection of adulterants in pure honey.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, we have presented the design considerations of lossy mode resonance (LMR) based tapered fiber optic sensors for sensitivity enhancement. The study includes the effect of the taper ...ratio and the taper profile, i.e. exponential-linear, linear, parabolic, gaussian and quadratic, on the sensitivity. Also, we have analyzed the effect of various coating materials on the sensitivity. It is revealed from the analysis that with an increase in the taper ratio, the sensitivity increases. The effect of the taper profile shows that among five profiles considered for comparison, the exponential-linear profile has the maximum sensitivity value whereas the quadratic profile has the lowest value. For indium tin oxide (ITO), for the exponential-linear taper profile, the sensitivity corresponding to the first and second lossy modes is 12.005 µm/RIU (refractive index unit) and 0.8 µm/RIU, respectively, at the taper ratio 1.7; whereas for aluminum doped zinc oxide (AZO), the corresponding values are 0.515 µm/RIU and 0.235 µm/RIU, respectively, at the taper ratio 2.0. For surface plasmon resonance (SPR) based tapered fiber optic sensors, the maximum sensitivity value for the exponential-linear taper profile for platinum is 6.39 µm/RIU at the taper ratio 2.0, whereas for copper its value is 3.665 µm/RIU. At the taper ratio 1.0, i.e. the uniform core, the sensitivity of the LMR based tapered fiber optic sensors using an ITO coating is two times greater than the platinum-coated SPR based fiber optic sensor. Increasing the taper ratio further enhances the sensitivity around 40% when compared to the uniform core fiber optic sensor. Therefore, LMR based tapered fiber optic sensors with the considered optimum design parameters demonstrate around a 2.5-fold enhancement in sensitivity compared with conventionally used SPR based fiber optic sensors, giving an optimum structure for sensitivity enhancement. We believe that this study will find suitable applications in research/industry for those working in the area of chemical and biological sensing.
The present manuscript describes the theoretical understanding of nanoporous alumina based fiber optic sensing structures. The Cavity Maxwell Garnett theory is used to calculate the dielectric ...functions of the proposed layer. The performance of the proposed sensing structure is evaluated in terms of its sensitivity towards change in the refractive index of the nearby medium. The sharpness of the resonance has also been calculated as an estimation of the performance parameters. It has been observed that the proposed structure is approximately 13 times more sensitive than the conventional fiber optic sensors. The study has further been extended by replacing the nanolayer of aluminum with the nanolayer of the gold. A comparative study has been provided in terms of the efficiency of the fiber optic probe. The effects of change in pore radius, thickness of the adsorbed medium and shell radius have also been studied.
A surface plasmon resonance (SPR) based optical fiber sensor, employing few layers of
Ti
3
C
2
MXene on a thin gold (Au) film to enhance the sensitivity of the sensor is theoretically proposed. The ...detection accuracy (DA) and the figure of merit (FOM), the two other important performance parameters, have also been assessed for the proposed configuration. Moreover, a comparative investigation of
Ti
3
C
2
MXene with transition metal dichalcogenide (TMDC) materials such as
MoS
2
,
MoSe
2
and
WS
2
coated over Au film is also carried out. The sensor configuration with fiber core/Au layer/few layer
Ti
3
C
2
MXene comes out to be most sensitive when compared with the analogous configuration having TMDC materials instead of
Ti
3
C
2
MXene. The proposed sensor configuration shows up to 49% enhancement in the sensitivity by using few layer
Ti
3
C
2
MXene. Thus, present work divulges potential applications of few layer
Ti
3
C
2
MXene which comes out to be a promising chemical and bio-sensing material. It is believed that the use of few layer
Ti
3
C
2
MXene could find favorable applications in the designing of high sensitivity SPR based refractive index sensors.
Graphic abstract
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Topological insulators having topologically protected metallic surface state emerged out as new building blocks in electronics and photonics. In this paper, a high figure of merit (FOM) fiber optic ...surface plasmon resonance (SPR) sensor employing topological insulator, Bi
1.5
Sb
0.5
Te
1.8
Se
1.2
, is proposed theoretically. The designed SPR sensor utilizes wavelength interrogation-based Kretschmann–Raether configuration to evaluate the transmitted power using transfer matrix method. Maximum FOM achieved was 360.16 RIU
−1
for the fiber configuration having 20-layers of Bi
1.5
Sb
0.5
Te
1.8
Se
1.2
coated over thin silver film. The performance of the sensor is also evaluated in terms of sensitivity and detection accuracy values. Authors believe that the derived results with enhanced performance can significantly boost the potential applications of topological insulators and hence BSTS material can find propitious chemical and biological sensing applications in future.
Induced pluripotency is a new approach to produce embryonic stem-like cells from somatic cells that provides a unique means to understand both pluripotency and lineage assignment. To investigate ...whether this technology could be applied to endangered species, where the limited availability of gametes makes production and research on embryonic stem cells difficult, we attempted generation of induced pluripotent stem (iPS) cells from snow leopard (Panthera uncia) fibroblasts by retroviral transfection with Moloney-based retroviral vectors (pMXs) encoding four factors (OCT4, SOX2, KLF4 and cMYC). This resulted in the formation of small colonies of cells, which could not be maintained beyond four passages (P4). However, addition of NANOG, to the transfection cocktail produced stable iPS cell colonies, which formed as early as D3. Colonies of cells were selected at D5 and expanded in vitro. The resulting cell line was positive for alkaline phosphatase (AP), OCT4, NANOG, and Stage-Specific embryonic Antigen-4 (SSEA-4) at P14. RT-PCR also confirmed that endogenous OCT4 and NANOG were expressed by snow leopard iPS cells from P4. All five human transgenes were transcribed at P4, but OCT4, SOX2 and NANOG transgenes were silenced as early as P14; therefore, reprogramming of the endogenous pluripotent genes had occurred. When injected into immune-deficient mice, snow leopard iPS cells formed teratomas containing tissues representative of the three germ layers. In conclusion, this was apparently the first derivation of iPS cells from the endangered snow leopard and the first report on induced pluripotency in felid species. Addition of NANOG to the reprogramming cocktail was essential for derivation of iPS lines in this felid. The iPS cells provided a unique source of pluripotent cells with utility in conservation through cryopreservation of genetics, as a source of reprogrammed donor cells for nuclear transfer or for directed differentiation to gametes in the future.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Macrofungi have long been investigated for various scientific purposes including their food and medicinal characteristics. Their role in aerobiology as a fraction of the primary biological aerosol ...particles (PBAPs), however, has been poorly studied. In this study, we present a source of macrofungi with two different but interdependent objectives: (i) to characterize the macrofungi from a tropical dry evergreen biome in southern India using advanced molecular techniques to enrich the database from this region, and (ii) to assess whether identified species of macrofungi are a potential source of atmospheric PBAPs. From the DNA analysis, we report the diversity of the terrestrial macrofungi from a tropical dry evergreen biome robustly supported by the statistical analyses for diversity conclusions. A total of 113 macrofungal species belonging to 54 genera and 23 families were recorded, with Basidiomycota and Ascomycota constituting 96% and 4% of the species, respectively. The highest species richness was found in the family Agaricaceae (25.3%) followed by Polyporaceae (15.3%) and Marasmiaceae (10.8%). The difference in the distribution of commonly observed macrofungal families over this location was compared with other locations in India (Karnataka, Kerala, Maharashtra, and West Bengal) using two statistical tests. The distributions of the terrestrial macrofungi were distinctly different in each ecosystem. We further attempted to demonstrate the potential role of terrestrial macrofungi as a source of PBAPs in ambient air. In our opinion, the findings from this ecosystem of India will enhance our understanding of the distribution, diversity, ecology, and biological prospects of terrestrial macrofungi as well as their potential to contribute to airborne fungal aerosols.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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