Adsorption Mechanism of Longchain Alkylamines on Quartz and Albite

The mechanism of adsorption of long-chain alkylamines at pH 6-7 onto quartz and albite using the direct methods of FTIR and XPS spectroscopy. The spectroscopic data were correlated with the data of indirect methods of zeta-potential measurements and Hallimond flotation results. It was shown from infrared spectra that the amine cation forms strong hydrogen bonds with surface silanol groups. The XPS spectra revealed the presence of molecular amine together with the protonated amine on silicate surface. Based on these observations, a model of successive two-dimensional and three-dimensional precipiation was suggested to explain amine adsorption on silicate surface

On the stranding of whales along the Tamil nadu and Andhra coasts

Two young female pilot whales Globicephala macrorhyma were caught in the gill nets by a 10 m mechanised boat at Pudukuppam near Cuddalore along the Tamil Nadu coast. The two whales measured 3.02 and 1.40 m in total length respectively. . The fishermen atPomraaiyarpalayam near Pondicherry noticed a whale identified as young female sperm whale Physeter macrocephalus which measured 5.55 m. T he local fishermen at MotupalJy near Ramachandrapuram in Prakasam District of Andhra Pradesh noticed a whale was identified as blue whale Balaenoptera musculu. The various morphometric measurements of these whales listed in detail and tabled

Adsorption Mechanism of Mixed Long-chain Amines and Alcohols on Silicate Minerals

The mechanism of adsorption of long chain alkyl primary amines and co-adsorption of amines and alcohols on silicate minerals (quartz and feldspar) were studied using FTIR (DRIFT and IRRAS) and XPS spectroscopy methods at neutral pH 6-7. The spectroscopic data were correlated with zeta-potential and Hallimond flotation results. The influence of long chain alcohols on the adsorption of amines in mixed amine-alcohol is also examined. The infrared studies revealed that the amine cation form strong hydrogen bonds with the surface silanol groups. The XPS spectra revealed the presence of molecular amine together with the protonated amine on silicate surface. Based on these observations, a model of successive two-dimensional and three-dimensional precipitation was suggested to explain amine adsorption on a silicate surface. The co-adsorption of long chain alcohols with amine cations leads to formation of a closer packed surface layer with synergistic enhancement of amine adsorption. The enhanced adsorption and hence higher flotation recoveries is discussed in the light of our experimental results

Growth performance of the seabass Lates calcarifer (Blotch) in sea cage at Vizhinjam Bay along the south-west coast of India

The growth potential of the Asian seabass, Lates calcarifer in floating sea cage was assessed by rearing them in a large HDPE floating cage moored at Vizhinjam Bay, south-west coast of India. Seabass seed (mean weight and mean total length, 2.5 g and 53 mm respectively) were nursery reared in hapas in December 2008, fed on pellet feed and grown to an average size of 28 g and 135 mm in 60 days, with a survival rate of 60%. Subsequently, the juveniles were stocked into the cages at a stocking rate of 60 nos. m-3 in February 2009, fed on trash fish and reared for a period of 112 days during which they grew to an average size of 540 g and 328 mm. Weight gain per day increased from 0.2 g in December 2008 to 7.71 g in May 2009, while SGR decreased from 5.88 to 2.47. The hydrological parameters viz., temperature, pH, salinity, dissolved oxygen and microbial load recorded were at optimal levels for the normal growth of seabass. The results obtained indicated that cage culture of seabass in the sea can provide significant advantages in terms of faster growth and effective utilisation of water volume

Rotational averaging-out gravitational sedimentation of colloidal dispersions and phenomena

We report on the differences between colloidal systems left to evolve in the earth's gravitational field and the same systems for which a slow continuous rotation averaged out the effects of particle sedimentation on a distance scale small compared to the particle size. Several systems of micron-sized colloidal particles were studied: a hard sphere fluid, colloids interacting via long-range electrostatic repulsions above the freezing volume fraction, an oppositely charged colloidal system close to either gelation and/or crystallization, colloids with a competing short-range depletion attraction and a long-range electrostatic repulsion, colloidal dipolar chains, and colloidal gold platelets under conditions where they formed stacks. Important differences in the structure formation were observed between the experiments where the particles were allowed to sediment and those where sedimentation was averaged out. For instance, in the case of colloids interacting via long-range electrostatic repulsions, an unusual sequence of dilute-Fluid/dilute-Crystal/dense-Fluid/dense-Crystal phases was observed throughout the suspension under the effect of gravity, related to the volume fraction dependence of the colloidal interactions, whereas the system stayed homogeneously crystallized with rotation. For the oppositely charged colloids, a gel-like structure was found to collapse under the influence of gravity with a few crystalline layers grown on top of the sediment, whereas when the colloidal sedimentation was averaged out, the gel completely transformed into crystallites that were oriented randomly throughout the sample. Rotational averaging out gravitational sedimentation is an effective and cheap way to estimate the importance of gravity for colloidal self-assembly processes.Comment: 13 pages, 13 figure

Panax ginseng Modulates Cytokines in Bone Marrow Toxicity and Myelopoiesis: Ginsenoside Rg1 Partially Supports Myelopoiesis

In this study, we have demonstrated that Korean Panax ginseng (KG) significantly enhances myelopoiesis in vitro and reconstitutes bone marrow after 5-flurouracil-induced (5FU) myelosuppression in mice. KG promoted total white blood cell, lymphocyte, neutrophil and platelet counts and improved body weight, spleen weight, and thymus weight. The number of CFU-GM in bone marrow cells of mice and serum levels of IL-3 and GM-CSF were significantly improved after KG treatment. KG induced significant c-Kit, SCF and IL-1 mRNA expression in spleen. Moreover, treatment with KG led to marked improvements in 5FU-induced histopathological changes in bone marrow and spleen, and partial suppression of thymus damage. The levels of IL-3 and GM-CSF in cultured bone marrow cells after 24 h stimulation with KG were considerably increased. The mechanism underlying promotion of myelopoiesis by KG was assessed by monitoring gene expression at two time-points of 4 and 8 h. Treatment with Rg1 (0.5, 1 and 1.5 µmol) specifically enhanced c-Kit, IL-6 and TNF-α mRNA expression in cultured bone marrow cells. Our results collectively suggest that the anti-myelotoxicity activity and promotion of myelopoiesis by KG are mediated through cytokines. Moreover, the ginsenoside, Rg1, supports the role of KG in myelopoiesis to some extent

Adsorption mechanism of mixed cationic/anionic collectors in feldspar-quartz flotation system

The adsorption mechanism of mixed cationic alkyl diamine and anionic sulfonate/oleate collectors at acidic pH values was investigated on microcline and quartz minerals through Hallimond flotation, electrokinetic and diffuse reflectance FTIR studies. In the presence of anionic collectors, neither of the minerals responded to flotation but the diamine flotation of the minerals was observed to be pH and concentration dependent. The presence of sulfonate enhanced the diamine flotation of the minerals by its co-adsorption. The difference in surface charge between the minerals at pH 2 was found to be the basis for preferential feldspar flotation from quartz in mixed diamine/sulfonate collectors. The infrared spectra revealed no adsorption of sulfonate collector when used alone but displayed its co-adsorption as diamine–sulfonate complex when used with diamine. The presence of sulfonate increased the diamine adsorption due to a decrease in the electrostatic head–head repulsion between the adjacent surface ammonium ions and thereby increasing the lateral tail–tail hydrophobic bonds. The mole ratio of diamine/sulfonate was found to be an important factor in the orientation of alkyl chains and thus the flotation response of minerals. The increase in sulfonate concentration beyond diamine concentration leads to the formation of soluble 1:2 diamine–sulfonate complex or precipitate and the adsorption of these species decreased the flotation since the alkyl chains are in chaotical orientation with a conceivable number of head groups directing towards the solution phase