We designed an obstructed Cauchy filter to improve the microscope resolution, and we calculated the point spread function (PSF) considering the Fourier transform operation deduced from the known ...Fraunhofer diffraction. Then, we computed the coherent transfer function (CTF) from the autocorrelation of the modulated Cauchy aperture. We applied the modulated Cauchy pupils to a confocal scanning laser microscope (CSLM) and examined the obtained images. We compared the images with the case of uniform circular apertures. We used the MATLAB code to make all the images and plots.
We constructed a new concentric black and white (B/W) hexagonal aperture, and we resized the image in a matrix of dimensions 1024 × 1024 pixels using MATLAB code. We derived a new formula for the ...point spread function (PSF) corresponding to the B/W hexagonal aperture. We computed the PSF using the Fast Fourier transform and compared the results with the case of a transparent hexagonal shape. In addition, we computed the coherent transfer function (CTF) for two symmetric objectives provided with the B/W hexagonal aperture. Finally, we reconstructed the image from the input object located in the confocal plane of the microscope provided with the modulated hexagonal apertures. We showed that the full width of the central lobe is smaller than that corresponding to the transparent hexagonal aperture hence improved resolution is attained in the case of B/W hexagonal aperture. In addition, we showed significant Legs of diffraction pattern corresponding to the B/W concentric hexagonal aperture. Then the PSF is dependent on the geometry of the B/W hexagonal aperture. We conclude that the image resolution which depends on the PSF is improved in the case of B/W hexagonal aperture while the image contrast is affected by the transmitted intensity in the detection plane of the confocal microscope. The coherent transfer function (CTF) or the autocorrelation corresponding to the B/W concentric hexagonal aperture has triangular decaying fringing as compared to that corresponding to the uniform hexagonal and circular apertures.
Drought and heavy metal stress undesirably disturb soil fertility and plant growth. Heavy metals pose severe biological toxic effects. Biochar, a carbon rich source application ameliorates this ...stress by increasing the plant growth, biomass, nutrient uptake and improves gaseous exchange in drought stress. Application of biochar reduces drought stress by increasing water holding capacity of soil through modification of soil physio-chemical properties that in turn increases water availability to plants and also enhances mineral uptake and regulation of stomatal conductance. Biochar mediates the retention of moisture, nutrients, inhibits harmful bacteria, absorbs heavy metals, pesticides, prevents soil erosion, increases soil pH, improves cationic exchange and boosts soil fertility. Drought and heavy metal stress often lead to production of reactive oxygen species. However, biochar significantly modifies the Reactive Oxygen Species (ROS) scavenging enzymes and provides an efficient electron transferring mechanism to tackle the toxic effects of ROS in plants. Biochar is regarded as a tool for the effective management of agricultural productivity and various environmental issues. This review provides insights on the potential role of biochar in ameliorating drought and heavy metal stress.
Display omitted
•Drought and heavy metal toxicity negatively affect soil fertility and plant growth.•Biochar supplementation manages agricultural productivity and environmental issues.•Application of biochar helps in modifying the physio-chemical properties of soil.•Biochar application enhances water and mineral uptake and boosts soil fertility.•Biochar plays a pivotal role in heavy metal remediation from contaminated soils.
Barium strontium titanate (Ba
1-
x
Sr
x
TiO
3
) is a novel material that has significantly contributed to most electronic industries. Ba
1-
x
Sr
x
TiO
3
is synthesized by a new sol–gel method with a ...different composition (
x
= 0.3 to 0.6). (Ba, Sr) acetate is a source of (Ba
+2
, Sr
+2
ions) and titanate isopropoxide is a source of Ti
+4
. The particle size of each sample was revealed by FESEM images, showing a reduction from 197 to 46 nm when the x ratio increased from 0.3 to 0.6. The X-ray diffraction revealed the phases of all the samples. Ba
0.7
Sr
0.3
TiO
3
appeared as a tetragonal phase. The remaining samples were shown to be in the cubic phase. As the concentration of Sr
+2
ions rose, the major peak intensity decreased, and its angles changed. The dielectric constant was investigated for all samples. It was studied as a function of temperature and frequencies. The dielectric constant was higher for the
x
= 0.3 sample than the remaining ratio. The optical constant was investigated. The energy bandgap was decreased with an increase in Sr
+2
ions and transmittance, and absorbance also varied with increases in Sr
+2
ions.
Barium strontium titanate (BST) Ba
1−
x
Sr
x
TiO
3
nanopowders have been successfully synthesized using the sol-gel route. This systematic study examines the effects of increasing strontium ions on ...the structural, morphological, and optical properties of the BaSrTiO
3
compound. The x-ray diffraction (XRD) results revealed that the polycrystalline barium strontium titanate (BST) phase was formed at greater than 700°C. The samples crystallize in pure perovskite and change from tetragonal to pseudo-cubic or cubic when Sr
+2
ions increase. In addition, the effect of Sr
+2
ion replacement on the crystal structure and optical characteristics of Ba
1−
x
Sr
x
TiO
3
particles (with x ranging from 0.2 to 0.6) was studied. The rise in Sr
+2
from
x
= (0.2 to 0.6) reduced particle sizes from 91.39, nm 288.89 nm, 144.88 nm, 86.42 nm, and 46 nm revealed by field emission scanning electron microscopy. With the increase in Sr
+2
ions, the density, lattice parameter, particle size and cell volume are reduced. The percentage of porosity increased as the concentration of Sr
+2
ions increased. Spectrophotometer readings indicated that the optical gap energy changed with Sr
+2
ion concentration x. The optical gap energy changed toward low energy and fell from 3.6 eV to 3.2 eV when the ion concentration of Sr
+2
rose from 0.2 to 0.6.
Cerium oxide (CeO
2
) thin films as humidity sensors are obtained by pulsed laser deposition (PLD) grown on Si (100) substrate. CeO
2
nanoparticles were taken as target materials for PLD technique. ...The effect of film deposition condition, such as deposition temperature on performance sensor, was explored. The substrate temperature ranges varied from 300 to 700 °C. The structural and surface morphologies were examined by X-ray diffractometer (XRD) and scanning electronic microscopy (SEM), respectively. The capacitance and resistance of the sensors were tested. The sensor utilizing CeO
2
films exhibited high sensitivity, and the increase in humidity led to a gradual increase in sensitivity and decreased resistance. The sensor performance is highly dependent on morphology and surface, which in turn is affected by the change in electrical properties of the film.
Due to their versatile applications, ZnONPs have been formulated by several approaches, including green chemistry methods. In the current study, convenient and economically viable ZnONPs were ...produced using Elaeagnus angustifolia (EA) leaf extracts. The phytochemicals from E. angustifolia L. are believed to serve as a non-toxic source of reducing and stabilizing agents. The physical and chemical properties of ZnONPs were investigated employing varying analytical techniques (UV, XRD, FT-IR, EDX, SEM, TEM, DLS and Raman). Strong UV-Vis absorption at 399 nm was observed for green ZnONPs. TEM, SEM and XRD analyses determined the nanoscale size, morphology and crystalline structure of ZnONPs, respectively. The ZnONPs were substantiated by evaluation using HepG2 (IC
: 21.7 µg mL
) and HUH7 (IC
: 29.8 µg mL
) cancer cell lines and displayed potential anticancer activities. The MTT cytotoxicity assay was conducted using Leishmania tropica "KWH23" (promastigotes: IC
, 24.9 µg mL
; and amastigotes: IC
, 32.83 µg mL
). ZnONPs exhibited excellent antimicrobial potencies against five different bacterial and fungal species via the disc-diffusion method, and their MIC values were calculated. ZnONPs were found to be biocompatible using human erythrocytes and macrophages. Free radical scavenging tests revealed excellent antioxidant activities. Enzyme inhibition assays were performed and revealed excellent potential. These findings suggested that EA@ZnONPs have potential applications and could be used as a promising candidate for clinical development.
Fourier transform (FT) corresponding to the diffuser has a comb function realised from uniform illumination, and hence the speckle image is nearly equal to comb point spread function (PSF). ...Consequently, the resulted distribution permits computation of the speckle size from the FWHM corresponding to the PSF of the
HG
nm
annular aperture. In the second method, the numerical autocorrelation of the speckle images using new apertures are computed and the speckle sizes are obtained. The results in both methods are compared with the speckle images obtained using circular aperture. It is noted that, the maximum number of spots produced in the
HG
nm
modes given by combinations
m
,
n
∈
0, 5 is
(
m
+
1
)
(
n
+
1
)
=
36
and all images and plots are obtained using Mat-Lab codes.
Summary
Microeukaryotes play key ecological roles in the microbial web of aquatic ecosystems. However, large knowledge gaps urgently need to be filled regarding the biogeography with associated ...shaping mechanisms and co‐occurrence patterns of microeukaryotes under freshwater‐saltwater gradients, especially true in tropical regions. Here, we investigated microeukaryotes of six mixed freshwater‐saltwater regions in the Pearl River Estuary and surrounding coasts in southern China, with salinity ranging 0.1–32.0% and distances spanned up to 500 km, using molecular ecological methods. Results indicate that the biogeography of abundant and rare microeukaryotic communities was similar, both their co‐occurrence patterns and biogeographical patterns were driven by deterministic and stochastic processes. The environmental factors with higher selective pressure than dispersal limitation meant that the role of deterministic process in structuring communities was more significant than that of stochastic process, and salinity played important role in structuring both microeukaryotic communities and networks. The abundant communities had stronger influence on entire microeukaryotic communities and seemed to be more sensitive to environmental changes than their rare counterparts, while rare ones had stronger interspecific relationships. Finally, the geographic scale and environmental gradients of study regions should firstly be clarified in future research on the ecological processes of microeukaryotes before conclusions are drawn.
A Note on S-Nakayama’s Lemma Hamed, A.
Ukrainian mathematical journal,
06/2020, Letnik:
72, Številka:
1
Journal Article
Recenzirano
We propose an
S
-version of Nakayama’s lemma. Let
R
be a commutative ring, let
S
be a multiplicative subset of
R,
and let
M
be an
S
-finite
R
-module. Also let
I
be an ideal of
R.
We show that if ...there exists
t
∈
S
such that
tM
⊆
IM,
then (
t'
+
a
)
M
= 0 for some
t'
∈
S
and
a
∈
I.
We also present an analog of Nakayama’s lemma for a
w
-ideal and an
S
-
w
-finite
R
-module, where
R
is an integral domain. Thus, we generalize the result obtained by Wang and McCasland Comm. Algebra, 25, 1285–1306 (1997).
PDF
