10 research outputs found
The Combined Use of in Silico, in Vitro, and in Vivo Analyses to Assess Anti-cancerous Potential of a Bioactive Compound from Cyanobacterium Nostoc sp. MGL001
Escalating incidences of cancer, especially in developed and developing countries, demand evaluation of potential unexplored natural drug resources. Here, anticancer potential of 9-Ethyliminomethyl-12-(morpholin-4-ylmethoxy)-5,8,13,16-tetraaza -hexacene-2,3-dicarboxylic acid (EMTAHDCA) isolated from fresh water cyanobacterium Nostoc sp. MGL001 was screened through in silico, in vitro, and in vivo studies. For in silico analysis, EMTAHDCA was selected as ligand and 11 cancer related proteins (Protein Data Bank ID: 1BIX, 1NOW, 1TE6, 2RCW, 2UVL, 2VCJ, 3CRY, 3HQU, 3NMQ, 5P21, and 4B7P) which are common targets of various anticancer drugs were selected as receptors. The results obtained from in silico analysis showed that EMTAHDCA has strong binding affinity for all the 11 target protein receptors. The ability of EMTAHDCA to bind active sites of cancer protein targets indicated that it is functionally similar to commercially available anticancer drugs. For assessing cellular metabolic activities, in vitro studies were performed by using calorimetric assay viz. 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT). Results showed that EMTAHDCA induced significant cytotoxic response against Dalton's lymphoma ascites (DLA) cells in a dose and time dependent manner with an inhibitory concentration (IC50) value of 372.4 ng/mL after 24 h of incubation. However, in case of normal bone marrow cells, the EMTAHDCA did not induce cytotoxicity as the IC50 value was not obtained even with higher dose of 1,000 ng/mL EMTAHDCA. Further, in vivo studies revealed that the median life span/survival days of tumor bearing mice treated with EMTAHDCA increased significantly with a fold change of ~1.9 and 1.81 corresponding to doses of 5 and 10 mg/kg body weight (B.W.) of EMTAHDCA respectively, as compared to the DL group. Our results suggest that 5 mg/kg B.W. is effective since the dose of 10 mg/kg B.W. did not show any significant difference as compared to 5 mg/kg B.W. Taken together, our findings based on in silico, in vitro, and in vivo analyses suggest that EMTAHDCA has potential anticancer effects, and thus, can be considered for cancer treatment
Tensile-Strained Nanoscale Ge/In<sub>0.16</sub>Ga<sub>0.84</sub>As Heterostructure for Tunnel Field-Effect Transistor
Tensile
strained Ge/In<sub>0.16</sub>Ga<sub>0.84</sub>As heterostructure
was grown in situ by molecular beam epitaxy using two separated growth
chambers for Ge and III–V materials. Controlled growth conditions
led to the presence of 0.75% in-plane tensile strain within Ge layer.
High-resolution transmission electron microscopy confirmed pseudomorphic
Ge with high crystalline quality and a sharp Ge/In<sub>0.16</sub>Ga<sub>0.84</sub>As heterointerface. Atomic force microscopy revealed a
uniform two-dimensional cross-hatch surface morphology with a root-mean-square
roughness of 1.26 nm. X-ray photoelectron spectroscopy demonstrated
reduced tunneling-barrier-height compared with Ge/GaAs heterostructure.
The superior structural properties suggest tensile strained Ge/In<sub>0.16</sub>Ga<sub>0.84</sub>As heterostructure would be a promising
candidate for high-performance and energy-efficient tunnel field-effect
transistor applications
Structural and band alignment properties of Al2O3 on epitaxial Ge grown on (100), (110), and (111)A GaAs substrates by molecular beam epitaxy
Structural and band alignment properties of atomic layer Al2O3 oxide film deposited on crystallographically oriented epitaxial Ge grown in-situ on (100), (110), and (111)A GaAs substrates using two separate molecular beam epitaxy chambers were investigated using cross-sectional transmission microscopy (TEM) and x-ray photoelectron spectroscopy (XPS). High-resolution triple axis x-ray measurement demonstrated pseudomorphic and high-quality Ge epitaxial layer on crystallographically oriented GaAs substrates. The cross-sectional TEM exhibited a sharp interface between the Ge epilayer and each orientation of the GaAs substrate as well as the Al2O3 film and the Ge epilayer. The extracted valence band offset, ΔEv, values of Al2O3 relative to (100), (110), and (111) Ge orientations using XPS measurement were 3.17 eV, 3.34 eV, and 3.10 eV, respectively. Using XPS data, variations in ΔEv related to the crystallographic orientation were ΔEV(110)Ge\u3eΔEV(100)Ge≥ΔEV(111)Ge and the conduction band offset, ΔEc, related to the crystallographic orientation was ΔEc(111)Ge\u3eΔEc(110)Ge\u3eΔEc(100)Ge using the measured ΔEv, bandgap of Al2O3 in each orientation, and well-known Ge bandgap of 0.67 eV. These band offset parameters are important for future application of Ge-based p- and n-channel metal-oxide field-effect transistor design
Integration of SrTiO<sub>3</sub> on Crystallographically Oriented Epitaxial Germanium for Low-Power Device Applications
SrTiO<sub>3</sub> integration on crystallographic oriented (100), (110), and
(111) epitaxial germanium (Ge) exhibits a potential for a new class
of nanoscale transistors. Germanium is attractive due to its superior
transport properties while SrTiO<sub>3</sub> (STO) is promising due
to its high relative permittivity, both being critical parameters
for next-generation low-voltage and low-leakage metal-oxide semiconductor
field-effect transistors. The sharp heterointerface between STO and
each crystallographically oriented Ge layer, studied by cross-sectional
transmission electron microscopy, as well as band offset parameters
at each heterojunction offers a significant advancement for designing
a new generation of ferroelectric-germanium based multifunctional
devices. Moreover, STO, when used as an interlayer between metal and
n-type (4 × 10<sup>18</sup> cm<sup>–3</sup>) epitaxial
Ge in metal–insulator–semiconductor (MIS) structures,
showed a 1000 times increase in current density as well as a decrease
in specific contact resistance. Furthermore, the inclusion of STO
on n-Ge demonstrated the first experimental findings of the MIS behavior
of STO on n-Ge
Functionally Graded Interfaces: Role and Origin of Internal Electric Field and Modulated Electrical Response
We report the tunable electrical
response in functionally graded interfaces in lead-free ferroelectric
thin films. Multilayer thin film graded heterostructures were synthesized
on platinized silicon substrate with oxide layers of varying thickness.
Interestingly, the graded heterostructure thin films exhibited shift
of the hysteresis loops on electric field and polarization axes depending
upon the direction of an applied bias. A diode-like characteristics
was observed in current–voltage behavior under forward and
reverse bias. This modulated electrical behavior was attributed to
the perturbed dynamics of charge carriers under internal bias (self-bias)
generated due to the increased skewness of the potential wells. The cyclic sweeping
of voltage further demonstrated memristor-like current–voltage
behavior in functionally graded heterostructure devices. The presence
of an internal bias assisted the generation of photocurrent by facilitating
the separation of photogenerated charges. These novel findings provide
opportunity to design new circuit components for the next generation
of microelectronic device architectures