600 research outputs found
Is the high cu tolerance of trichoderma atroviride isolated from the cu-polluted sediment due to adaptation?: an in vitro toxicological study
The tolerance of Cu by Trichoderma atroviride, a tolerant fungus isolated from the drainage surface sediment of the Serdang Industrial Area was investigated under in vitro conditions. Only this fungus species can tolerate up to 600 mg/L of Cu on solid medium Potato Dextrose Agar based on the isolation of the most tolerant fungus from the polluted sediment. Toxicity test performed on T. atroviride, showed a maximum tolerance at 300 mg/L of Cu concentration when grown in liquid medium Potato Dextrose Broth (PDB). The EC50 value of the isolate was 287.73 mg/L of Cu concentration in PDB. The Cu concentration in the drainage surface sediment, where the T. atroviride was isolated from, was 347.64 μg/g while the geochemical distributions of the non-resistant and resistant fractions of Cu were 99.6 and 0.4%, respectively. The sediment data indicated that the drainage had greatly received anthropogenic Cu from the nearby industries which are involved in the manufacturing of plastics and electronic products. The present findings indicate that the high Cu tolerance showed by T. atroviride could be due to the well adaptation of the fungus to the Cu polluted sediment. Therefore, T. atroviride could be a potential bioremediator of Cu pollution in the freshwater ecosystem
Synergistic and antagonistic effects of Zinc Bioaccumulation with lead and antioxidant activities in centella asiatica
This study was carried out by using Centella asiatica grown using a hydroponic system under laboratory conditions to study synergistic and antagonistic effects of Zn bioaccumulation with added Pb and the changes in antioxidant activities in leaves and roots of C. asiatica. The antioxidant activities included superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX). The treatments Zn (2 ppm) + Pb (0.4 ppm) and Zn (4 ppm) + Pb (0.6 ppm) increased the accumulation of Zn in leaves by 14.06 and 16.84%, respectively, but decreased by 7.36% uptake in roots (Zn 4 ppm + Pb 0.6 ppm). This showed that Pb and Zn acted synergistically to Zn accumulation in leaves but antagonistically in roots. CAT and SOD activities in leaves were increased when Zn was added together with Pb. In roots, CAT, APX and SOD activities were increased but GPX was decreased. Owing to their sensitivities to Zn with Pb, SOD and CAT could be used as biomarkers to monitor the toxicity of Pb and Zn exposure in the leaves and roots of C. asiatica
Effects of metal-contaminated soils on the accumulation of heavy metals in different parts of centella asiatica: a laboratory study
Centella asiatica is widely used as a medicinal plant in Malaysia and other parts of the world. In the present study, the growth and uptake of heavy metal by C. asiatica were determined based on the plant exposure to different treatment of metal-contaminated soils under laboratory conditions. Heavy metals uptake in different parts of the plants namely roots, stems and leaves were determined. In general, it was found that the metal uptake capacity followed the order: roots > stems > leaves. Since a close positive relationship was established between the concentrations of metal accumulated in different parts of the plant and the metal levels in the most contaminated soil, C. asiatica has the potential of being used as a biomonitoring plant for heavy metal pollution in the polluted soils
Mutation signatures of carcinogen exposure: Genome-wide detection and new opportunities for cancer prevention
10.1186/gm541Genome Medicine63
Restriction of Helmholtz Model
The results of the experimental studies of physical mechanisms of energy dissipation in the oscillating
system in which air cavity held by the forces of magnetic levitation is used as the elastic element, and
magnetic fluid prepared on the basis of dispersing media with different viscosity level is used as the iner-tial element are considered in the article. Based on the obtained results the conclusion on the restriction of
the applicability of Helmholtz equation, caused by boundary effects is made.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3640
Wound healing properties of Eucheuma cottonii extracts in Sprague-Dawley rats.
Wounds are unavoidable events of life and arise due to agents that induce stress or injury. Wound has been a menace the world over and healing is a survival mechanism and represents an adaptation to the maintenance of normal anatomical structure and function. The objective of this study was to evaluate the potential wound healing properties of ethanolic and aqueous extracts of Eucheuma cottonii. A two centimeter diameter of skin excision wound was made on normal rats. Treatment with honey (100 mg/kg body weight) was used as positive control and untreated rats as the negative control groups. Inflammation and proliferation phases of wound healing including wound contraction, re-epithelization and granulation tissue development were monitored. This study showed that both seaweed extracts increased the rate of wound contraction compared with the positive and negative control. Ethanolic extract of E. cottonii was more effective than the aqueous extract by 20% (P<0.05). Histopathological findings showed the ethanolic extracts enhanced epithelization and tissue granulation significantly compared with both control groups. E. cottonii possesses several antioxidant compounds, which may be responsible for the accelerated wound healing. The present study demonstrated that these seaweed extracts accelerated healing better if not comparable with honey
Topological spin-Hall current in waveguided zinc-blende semiconductors with Dresselhaus spin-orbit coupling
We describe an intrinsic spin-Hall effect in -type bulk zinc-blende
semiconductors with topological origin. When electron transport is confined to
a waveguide structure, and the applied electric field is such that the spins of
electrons remain as eigenstates of the Dresselhaus spin-orbit field with
negligible subband mixing, a gauge structure appears in the momentum space of
the system. In particular, the momentum space exhibits a non-trivial Berry
curvature which affects the transverse motion of electrons anisotropically in
spin, thereby producing a finite spin-Hall effect. The effect should be
detectable using standard techniques in the literature such as Kerr rotation,
and be readily distinguishable from other mechanisms of the spin-Hall effect.Comment: 6 pages, 3 figure
Tolerance of High Inorganic Mercury of Perna Viridis : Laboratory Studies of Its Accumulation, Depuration and Distribution
The tolerance of Perna Viridis to a high inorganic mercury (Hg)
exposure was determined based on its accumulation, depuration and
distribution. The Hg accumulation of the mussel was conducted for a
4-day semi-static exposure at a \u2018very\u2019 high Hg
concentration (100 \u3bcg/L). None of the mussels died after the
experimental period, indicating that the elevated level of inorganic Hg
exposure was not toxic to P. viridis. Following the 4-day exposure, the
Hg concentrations were higher in the gill and byssus than in the
mantle, foot, gonad and muscle (with bioconcentration factor values
being between 13 and 625). The Hg distribution among the different soft
tissues after 11 days of depuration was almost similar with that after
Hg exposure. The high Hg levels found in the byssus and different soft
tissues after the depuration indicated that Hg accumulated in the
different ST was tightly bound to metallothionein and it was not easily
mobilized. The Hg distribution in the byssus and in the different soft
tissues could be due to their differing capacities for Hg accumulation
and depuration. Since the soft tissues of P. viridis can accumulate
inorganic Hg in high concentrations after exposing to a
\u2018very\u2019 high level of inorganic Hg, it has a high
bioaccumulative capability and a high tolerance to inorganic Hg. The
mussel byssus was found to have the highest depuration rate
coefficient, indicating that it could act as one of the excretion
routes for Hg and it can be proposed as a sensitive biomonitoring
material for Hg. The fecal materials released by the mussel had
elevated levels of Hg, indicating that the mussels acted as a Hg
retention mechanism in the coastal ecosystem
Adding flavor to Dijkgraaf-Vafa
We study matrix models related via the correspondence of Dijkgraaf and Vafa
to supersymmetric gauge theories with matter in the fundamental. As in
flavorless examples, measure factors of the matrix integral reproduce
information about R-symmetry violation in the field theory. The models, studied
previously as models of open strings, exhibit a large-M phase transition as the
number of flavors is varied. This is the matrix model's manifestation of the
end of asymptotic freedom. Using the relation to a quiver gauge theory, we
extract the effective glueball superpotential and Seiberg-Witten curve from the
matrix model.Comment: 15 pages, harvmac; improved analysis of the healing of cuts, added
calculation of superpotential, improved referencing and notatio
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