A series of fluorinated azobenzene esters have been synthesized and studied by polarized optical microscopy (POM) and UV-Vis spectrophotometry. The –CO 2 C 2 H 5 group with monofluoro-substituted ...azobenzene exhibited nematic and smectic phases whereas difluoro-substituted azobenzene showed only the nematic phase. The addition of the electronegative fluorine atom plays an important role in photoisomerization of the azobenzene molecules. The monofluoro-substituted azobenzene gave strong photoisomerization in solution as compared with its diflouro counterparts. In these systems, trans – cis isomerization occurred after 4 minutes and cis – trans isomerization occurred after 22 hours which is much longer than expected for fluorine-substituted azobenzene systems. The presented results might have an influence on creating optical data storage devices.
Abstract
This study designs to determine the effectiveness of Honeybee (HB) as cryoprotectants (CP) on viability vitrified-thawed bovine oocytes derived from OPU using Trehalose as control. Cattles ...were subjected to superstimulation protocol, per session conducted five days where three days both cattle were administrated 100 mg follicle stimulation hormone (FSH) within 24 h once and two days of “resting period” totalling two sessions. The “coasting period” (FSH starvation) between sessions was four days (96 h). Oocytes collection via OPU were performed at fifth day (120 h). The ovarian growth was observed via ultrasonographic before OPU. Prior to vitrifying oocytes with treatment Trehalose (T1) and HB (T2) followed by warming protocol, oocytes subjected to
in vitro
maturation (IVM). Oocytes viability were evaluated by fluorescein diacetate staining. Results showed ovarian growth for first session was larger size follicles than the second session for both cattle. Total number of oocytes obtained were 60. Oocytes viability treatment T2 was significantly higher (90.9%) than T1 (70.4%). This study concludes that HB as CP in vitrification protocol was able to achieved high oocytes viability with oocytes derived via OPU suggesting Honeybee as an alternative CP for oocytes vitrification.
Biosorption of cadmium (II) ions from aqueous solution onto immobilized cells of
Pycnoporus sanguineus (
P. sanguineus) was investigated in a batch system. Equilibrium and kinetic studies were ...conducted by considering the effect of pH, initial cadmium (II) concentration, biomass loading and temperature. Results showed that the uptake of cadmium (II) ions increased with the increase of initial cadmium (II) concentration, pH and temperature. Langmuir, Freundlich and Redlich–Peterson isotherm models were used to analyze the equilibrium data at different temperatures. Langmuir isotherm model described the experimental data well followed by Redlich–Peterson and Freundlich isotherm models. Biosorption kinetics data were fitted using pseudo-first, pseudo-second-order and intraparticle diffusion. It was found that the kinetics data fitted well the pseudo-second-order followed by intraparticle diffusion. Thermodynamic parameters such as standard Gibbs free energy (Δ
G
0), standard enthalpy (Δ
H
0) and standard entropy (Δ
S
0) were evaluated. The result showed that biosorption of cadmium (II) ions onto immobilized cells of
P. sanguineus was spontaneous and endothermic nature.
► Waste activated sludge (WAS) from palm oil mill effluent treatment plant turned into adsorbent via chemical activation without high thermal treatment. ► Obeys both Langmuir and Freundlich Isotherm ...with maximum monolayer adsorption capacity of 66.23
mg/g. ► Adsorption kinetics fits the pseudo-second order model. ► Methylene Blue (MB) adsorption onto WAS is exothermic and spontaneous. ► MB adsorbed onto WAS by electrostatic attraction.
Waste activated sludge (WAS) from palm oil mill effluent (POME) treatment plant was used to adsorb Methylene Blue (MB) in a batch system. The WAS was prepared at lower temperature compared to the previous studies. Parameters such as initial MB concentration, pH, and temperature were studied for their effects on the adsorption process. Results showed that the uptake of MB increased with an increase in both the initial MB concentration and the pH, and decreased with an increase in temperature. Both the Langmuir and the Freundlich Isotherms are fit to explain the MB adsorption on WAS. The maximum monolayer adsorption capacity of WAS was found to be 66.23
mg/g at 30
°C. The kinetic data for this study fit well the pseudo-second-order kinetic with a
R
2 more than 0.95. Thermodynamic analysis was performed by evaluating the Gibbs Free Energy (Δ
G°), enthalpy (Δ
H°), and entropy (Δ
S°) of the process. The evaluation showed that the MB adsorption process onto WAS is an exothermic process and is spontaneous in nature. Hence, this work reveals that the use of POME WAS is an innovative application of a local waste product as an adsorbent for MB removal.
The field of nanotechnology mainly encompasses with biology, physics, chemistry and material sciences and it develops novel therapeutic nanosized materials for biomedical and pharmaceutical ...applications. The biological syntheses of nanoparticles are being carried out by different macro–microscopic organisms such as plant, bacteria, fungi, seaweeds and microalgae. The biosynthesized nanomaterials have been effectively controlling the various endemic diseases with less adverse effect. Plant contains abundant natural compounds such as alkaloids, flavonoids, saponins, steroids, tannins and other nutritional compounds. These natural products are derived from various parts of plant such as leaves, stems, roots shoots, flowers, barks, and seeds. Recently, many studies have proved that the plant extracts act as a potential precursor for the synthesis of nanomaterial in non-hazardous ways. Since the plant extract contains various secondary metabolites, it acts as reducing and stabilizing agents for the bioreduction reaction to synthesized novel metallic nanoparticles. The non-biological methods (chemical and physical) are used in the synthesis of nanoparticles, which has a serious hazardous and high toxicity for living organisms. In addition, the biological synthesis of metallic nanoparticles is inexpensive, single step and eco-friendly methods. The plants are used successfully in the synthesis of various greener nanoparticles such as cobalt, copper, silver, gold, palladium, platinum, zinc oxide and magnetite. Also, the plant mediated nanoparticles are potential remedy for various diseases such as malaria, cancer, HIV, hepatitis and other acute diseases.
l
-asparaginase (LA) catalyzes the degradation of asparagine, an essential amino acid for leukemic cells, into ammonia and aspartate. Owing to its ability to inhibit protein biosynthesis in ...lymphoblasts, LA is used to treat acute lymphoblastic leukemia (ALL). Different isozymes of this enzyme have been isolated from a wide range of organisms, including plants and terrestrial and marine microorganisms. Pieces of information about the three-dimensional structure of
l
-asparaginase from
Escherichia coli
and
Erwinia
sp. have identified residues that are essential for catalytic activity. This review catalogues the major sources of
l
-asparaginase, the methods of its production through the solid state (SSF) and submerged (SmF) fermentation, purification, and characterization as well as its biological roles. In the same breath, this article explores both the past and present applications of this important enzyme and discusses its future prospects.
A study to illustrate the distribution of trace metals and rare earth elements (REEs) in Padina sp. as a bioindicator was done at 11 stations along the east coast of Peninsular Malaysia facing the ...South China Sea. The objectives of the study were to obtain baseline data for elemental concentrations (11 trace metals and 14 REEs), to evaluate the spatial variation and inter-elemental relationships, and to define the REEs pattern in seaweed. REEs were measured, as their known close relationship to the heavy metals may assist in the interpretation of metal sources and in determining whether or not there exists anthropogenic accumulation of the metals. Samples were ground to a fine powder, homogenised and quantified by inductively coupled plasma mass spectrometry (ICP-MS). Hg was detected by MA-2 Mercury Analyzer. Metals concentration showed significant variations in their distribution (p < 0.05) and most elements were in their same range of concentrations with the exception of Hg, Cd, Pb and Zn. The presented rank with high concentration of essential elements for metabolism, the partial exclusion of non-essential elements, and the enrichment of LREE over HREE is comparable to other literature. Mean level for metals and REEs were in low concentrations when compared to the literature. With regard to food safety, the concentrations of Hg, Cd, Pb and Zn on a wet weight basis were well within permissible limits set by the Malaysian Food Act. Chondrite and NASC-normalized REEs patterns of each station were generally similar to one another which suggested that they were of similar origin. The REE patterns in Padina sp. were indicative of their provenance from granite rocks, which is dominant in the Malay Peninsula, and volcanic rocks to a lesser extent. This study demonstrated that because of the close relationship of Fe and the contaminant metal Pb with the REEs, the relatively high concentrations of these metals point to their source being the granitic rocks.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
In this study, the interactive effects of feed flow rate (
Q
F) and up-flow velocity (
V
up) on the performance of an up-flow anaerobic sludge fixed film (UASFF) reactor treating palm oil mill ...effluent (POME) were investigated. Long-term performance of the UASFF reactor was first examined with raw POME at a hydraulic loading rate (HRT) of 3
d and an influent COD concentration of 44
300
mg/l. Extreme reactor instability was observed after 25
d. Raw POME was then chemically pretreated and used as feed. Anaerobic digestion of pretreated POME was modeled and analyzed with two operating variables, i.e. feed flow rate and up-flow velocity. Experiments were conducted based on a central composite face-centered design (CCFD) and analyzed using response surface methodology (RSM). The region of exploration for digestion of the pretreated POME was taken as the area enclosed by the feed flow rate (1.01, 7.63
l/d) and up-flow velocity (0.2, 3
m/h) boundaries. Twelve dependent parameters were either directly measured or calculated as response. These parameters were total COD (TCOD) removal, soluble COD (SCOD) removal, effluent pH, effluent total volatile fatty acid (TVFA), effluent bicarbonate alkalinity (BA), effluent total suspended solids (TSS), CH
4 percentage in biogas, methane yield (
Y
M), specific methanogenic activity (SMA), food-to-sludge ratio (F/M), sludge height in the UASB portion and solid retention time (SRT). The optimum conditions for POME treatment were found to be 2.45
l/d and 0.75
m/h for
Q
F and
V
up, respectively (corresponding to HRT of 1.5
d and recycle ratio of 23.4:1). The present study provides valuable information about interrelations of quality and process parameters at different values of the operating variables.
The development of passively driven microfluidic labs on chips has been increasing over the years. In the passive approach, the microfluids are usually driven and operated without any external ...actuators, fields, or power sources. Passive microfluidic techniques adopt osmosis, capillary action, surface tension, pressure, gravity-driven flow, hydrostatic flow, and vacuums to achieve fluid flow. There is a great need to explore labs on chips that are rapid, compact, portable, and easy to use. The evolution of these techniques is essential to meet current needs. Researchers have highlighted the vast potential in the field that needs to be explored to develop rapid passive labs on chips to suit market/researcher demands. A comprehensive review, along with patent analysis, is presented here, listing the latest advances in passive microfluidic techniques, along with the related mechanisms and applications.
Different approaches employed in the passively driven microfluidics and LOC devices.
The innovation of nanoparticles assumes a critical part of encouraging and giving open doors and conceivable outcomes to the headway of new era devices utilized as a part of biosensing. The focused ...on the quick and legitimate detecting of specific biomolecules using functionalized gold nanoparticles (Au NPs), and carbon nanotubes (CNTs) has turned into a noteworthy research enthusiasm for the most recent decade. Sensors created with gold nanoparticles or carbon nanotubes or in some cases by utilizing both are relied upon to change the very establishments of detecting and distinguishing various analytes. In this review, we will examine the current utilization of functionalized AuNPs and CNTs with other synthetic mixes for the creation of biosensor prompting to the location of particular analytes with low discovery cutoff and quick reaction.
•Wide range of and application of carbon nanotube and gold nanoparticles based on electrochemistry has been overviewed.•We have summarized and future outlooks the application of CNT and AuNP in different biosensing applications.•Wide range of readers will be benefited.
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