Survey of the properties of waxed duplex cartons used in frozen shrimp industry

Waxed duplex cartons collected from different prawn freezing factories were evaluated for their physico-chemical properties such as bursting strength, puncture resistance, water proofness, tearing, strength, tensile strength, elongation, moisture content, thickness, weight of the carton, dimension, wax content and saponifiable matter. The results are discussed from the point of view of formulation of standards for this most widely employed packaging material for frozen fishery products in the country.

Fish muscle structural proteins

Based on the differences in their physico-chemical properties proteins are broadly categorised as sarcoplasmic or fibrillar. The properties are important in fish technology. The authors review some of these physico-chemical properties of the proteins which have distinguished themselves as 'structural' or 'textural' proteins. As denaturation in these proteins caused by a variety of factors manifests itself in terms in the quality attributes of the product, relevant mechanisms have been particularly highlighted.

Photosynthetic bacteria in the marine environment at Porto-Novo

Sediment and water samples were collected from mangrove and estuarine biotopes at fortnightly intervals. The physico-chemical characters of the overlying water were studied. In the mangrove biotope maximum temperature (31.5°C) and in the estuarine biotope maximum salinity (35.6‰) were recorded during the summer season, whereas in post-monsoon period the sulphate content was increased to 516 p.p.m. and the pH was reduced to 7.4. Invariably both in the enriched sediment and water samples four major peaks (at wavelengths 460, 705, 772 and 850 nm) and two minor peaks (at wavelengths 580 and 663 nm) of absorption spectra were noticed. A pure culture of Chromatium sp., isolated from mangroves sediment, showed three peaks of absorption spectra at wavelengths, 500, 580 and 850 nm. The effect of sodium chloride on the growth of Chromatium sp., was also studied and it was observed that maximum growth occurred in the range 1-3% sodium chloride concentration. This isolate was also capable of utilizing various sulphur and carbon compounds. Glycerol and glucose did not show any specific effect whereas pyruvate, malate and acetate increased the growth.

Tolerance of Penaeus monodon larvae to cupric sulfate added in bath

Copper is used to deter the growth of bacterial, fungal and protozoan disease organism in fishes. Zoeae (Z SUB-1 ), myses (M SUB-1 ) and postlarvae (P SUB-1 ) were exposed to copper sulfate at concentrations of 0 . 025, 0 . 05, 0 . 75, 0 . 1 and 0 . 2 ppm from 24 to 96 hours. The number of surviving larvae were counted at the end of each 24-hour period and the percentage of survival is determined for each dose level. The LC SUB-50 for each of the larval stages was interpolated from the data whenever possible. Three trials with 2 replicates per trial were conducted. The physico-chemical characteristics of the bath taken before and at the end of the experimental period show insignificant differences between initial and final values in each trial. Results indicate that mortality rates of all larval stages increased with exposure time and that mortality rates of the experimental group is higher than the control. Interpolation of the LC SUB-50 is possible only for the 48-h and 72-h exposure times for both zoeae and myses and for the 48-h exposure time for the postlarvae. This is due to the high survival percentage of the 24-h group and the low survival percentage (below 50%) of the larvae exposed for 96 hours. The 48-hour LC SUB-50 for Z SUB-1 , M SUB-1 and P SUB-1 are 0 . 225, 0 . 350 and 0 . 125 ppm respectively. Postlarvae seem to be more sensitive than either of the 2 larval stages having a lower 48-h LC SUB-50 and a low survival rate after 72 hours. The larvae were observed to lose their balance and were lethargic, producing few swimming movements so that they were mostly confined to the bottom of the aquaria. Moribund larvae observed under the microscope had a faster but weak heartbeat compared to healthy larvae. Slight or complete loss of feeding ability indicated by empty guts and delayed molting of Z SUB-1 to Z SUB-2 were also noted.

Acute toxicity of metasystox to wedge clam, Donax cuneatus from west coast

96h acute toxicity tests were performed using commercial grade metasystox on the marine wedge clam, Donax cuneatus during summer 1985. The behaviour and mortality rates were recorded periodically. Most of the dams responded in opening the shell valves and extending the siphons quicker in low test concentrations (0.004-0.0052 p.p.m) but this was slow and late in high concentrations (0.0056-0.008 p.p.m). Mortality began to occur in 0.008 p.p.m. from 12 h, whereas, in 0.0052 p.p.m. from 60 h onwards. The observed LC sub(0) value was 0.004 p.p.m. and LC sub(50) 0.0064 p.p.m. The regression equation established was Y = 79.0891 + 33.4523 X. The rate of oxygen concentration increased at LC sub(0) and LC sub(50) values compared to control indicating the disturbed physiological adjustment. The results are correlated with physico-chemical parameters of seawater and discussed in the light of pesticide toxicity to the dam.

Impact of plankton structure on primary productivity in two beels of West Bengal, India

Planktonic community in floodplain wetlands embodies the energy transfer through this phase and indicates trophic status of lake. Originally rich bottom coupled with a conducive physicochemical environment encourages fast colonization of the plankton population. Present investigation was carried out in two floodplain wetlands having characteristics of open (Amda beel) and closed (Suguna beel) system. The physicochemical parameters of water and soil of the investigated heels were by and large conducive for planktonic growth. The density of plankton population varied between 1,346 and 2,170 u/l in Suguna bed whereas in Amda beel it ranged from 1,030 to 1,802 u/l. Seasonal fluctuations in water column were conspicuous and mostly dependent on the replenished resources and volume, A mixed and balanced population of diversified fauna constituted the plankton population of the investigated ecosystems. Mostly the diversity was observed to be maximum during winter seasons with coincidence of favorable temperature, dissolved oxygen and other physico-chemical parameters of water besides optimum solar penetration. Richness of planktonic structure in closed system (Suguna) resulted in higher fish production (1,570,05 kg/ha/yr) than that of open system (Amda) (384.4 kg/ha/yr).

Ecological impact of Mahshahr petrochemical activities on abundance and diversity of macrobenthic fauna in Zangi Creek (Persian Gulf)

The Moosa Creek extends from its opening into the Persian Gulf, with some sub narrow creeks leading to it. Zangi creek is one of the main branches of Moosa creek. The creek contains numerous sources of organic pollution, including sewage outlet flows and boat waste. After establishing the Petrochemical special Economic Zone (PETZONE) in 1997 near to the Zangi Creek, the pipelines, streets and railway made it distinct from eastern and western parts of this creek. Industrial activities have released sludge and effluents in this creek along these years. A survey of the Zangi creek was performed, assessing water properties, organic pollution, and the population density, distribution and diversity of macrobenthic fauna through bi-monthly sampling from July 2006 to September 2007. Samples were collected from water near the bottom and sediment at 7 stations include 2 stations inside the distinct Zangi creek and 4 stations along a transect with 1 km distances between them in eastern free part and one reference station located at the Persian Gulf entrance to the Moosa creek. The environmental parameters such as temperature, salinity, pH, dissolved oxygen, COD, turbidity, EC and heavy metals include Hg, Cd, Pb, Ni as well as percentage silt-clay and total organic matter of the sediment were measured. The faunal population density and their distribution are discussed in relation to the environmental changes. Results showed spatial heterogeneity in faunal distribution of the Zangi creek. Nine groups of macrofauna were identified out of distinct zangi creek. Polychaets formed the dominant group (48%) followed by bivalves (13%), gastropods (10%), Decapods (2%), Tanaids (5%), and all other groups (22%). The distinct creek was heavily polluted without any macrofauna communities probably as a consequence of the high pH, COD, low salinity and heavy metals contamination specially Cd and Pb. The other stations near to the disposal site were found with macrofauna communities commonly tolerant to organic pollution, At 3 km east of the disposal site, macrofauna is comparable to the surrounded creek, whereas macrofauna still indicate environmental degradation. Farther a way, faunal density decreases and equilibrium taxa gradually replace opportunistic species, while the other stations were far from polluted area contained lower pollution and relatively healthy macrofauna. The mean biomass of macrobenthic fauna were estimated for the whole studied area. The results are considered in Minimum density and biomass in surrounded creek and maximum density and biomass in 3 km of surrounded area. Biodiversity Indices were low in surrounded creek. The Shanon-weaver information index was used to describe the spatially variations in diversity. Macrofauna density, shanon and simpson index were significantly variable between surrounded and free parts of Zangi creek (p<0.05). The numerical abundance of macrobenthose varied from 221. m-2 in polluted area to 4346 m-2 in free part of Zangi creek. The Shanon-weaver information index varied from 0.4 in distinct area to 2.9 in reference station. The physico- chemical changes between distinct and free creeks showed significant variations such as pH, salinity and EC. Salinity and EC were significantly positive correlate to macrofauna density, whereas pH and TOM percentage indicated significantly negative correlation to density. Heavy metals concentrations in sediments were higher than water samples. Concentration pattern of heavy metals in sediments and water samples were Ni>Pb>Cd>Hg. Salinity and pH were significantly correlated to metals in sediments (p<0.01). No significant correlation were found between Macrofauna density and heavy metals (p<0.05).

Genetic diversity of Saccostrea cucullata population in the northern coast in Persian Gulf and Oman Sea

Genetic diversity of Saccostrea cucullata in the northern coast lines of the Persian Gulf and the Sea of Oman were determined using DNA extraction and RAPD - PCR. A total of 300 samples were collected from 6 station along the coastline. Two out of six primers showed positive results namely GCG - ATC - CCC - A (Primer 1) and GTC - CAC - ACG - C (Primer 5) which were in accordance with morphometric analysis. The number of bands in the two above - mentioned primers in Khor - Tang and Chabahar station (Province of Sistan and Balouchestan) was significantly different from the number of produced bands in Dayer and Bushehr station (Province of Bushehr) as well as Gheshm and Bandar - Lengeh station (Province of Hormozgan). The cluster analisys was used to confirm the above variations. The results showed that the oyster population can be divided into two separate clusters. The first cluster included Bushehr Dayer Gheshm and Bandar - Lengeh species. The second cluster included Khor - Tang and Chabahar species. The analysis also showed that the first cluster can be divided into two Sub — cluster. Bushehr and Dayer belong to one Sub - cluster whereas Gheshm and Bandar - Lengeh form the other Sub — cluster. The formation of different vluster can be related to Physico - Chemical properties of water and climatic variations in different habitats along the Persion Gulf and the Sea of Oman. Key words: Molecular genetics, Population, RAND, PCR' Saccostrea cucullata

Chemical surface modification of poly-ε-caprolactone improves Schwann cell proliferation for peripheral nerve repair.

Poly-ε-caprolactone (PCL) is a biodegradable and biocompatible polymer used in tissue engineering for various clinical applications. Schwann cells (SCs) play an important role in nerve regeneration and repair. SCs attach and proliferate on PCL films but cellular responses are weak due to the hydrophobicity and neutrality of PCL. In this study, PCL films were hydrolysed and aminolysed to modify the surface with different functional groups and improve hydrophilicity. Hydrolysed films showed a significant increase in hydrophilicity while maintaining surface topography. A significant decrease in mechanical properties was also observed in the case of aminolysis. In vitro tests with Schwann cells (SCs) were performed to assess film biocompatibility. A short-time experiment showed improved cell attachment on modified films, in particular when amino groups were present on the material surface. Cell proliferation significantly increased when both treatments were performed, indicating that surface treatments are necessary for SC response. It was also demonstrated that cell morphology was influenced by physico-chemical surface properties. PCL can be used to make artificial conduits and chemical modification of the inner lumen improves biocompatibility.

Ultraviolet-B exposure induces photo-oxidative damage and subsequent repair strategies in a desert cyanobacterium Microcoleus vaginatus Gom.

Biological soil crusts are important in reversing desertification. Ultraviolet radiation, however, may be detrimental for the development of soil crusts. The cyanobacterium Microcoleus vaginatus can be a dominant species occurring in desert soil crusts all over the world. To investigate the physico-chemical consequences of ultraviolet-B radiation on M. vaginatus, eight parameters including the contents of chlorophyll a, reactive oxygen species, malondialdehyde and proline, as well as the activities of photosynthesis, superoxide dismutase (EC 1.15.1.1), peroxiclase (EC 1.11.1.7) and catalase (EC 1.11.1.6) were determined. As shown by the results of determinations, ultraviolet-B radiation caused decreases both in contents of chlorophyll a and in ratios of variable fluorescence over maximum fluorescence that indicate the growth and photosynthesis of M. vaginatus, besides, increases both in levels of reactive oxygen species and in contents of malondialdehyde and proline, while intensified activities of superoxide dismutase, peroxiclase and catalase reflecting the abilities of enzymatic preventive substances to oxidative stress of the treated cells. Therefore, ultraviolet-B radiation affects the growth of M. vaginatus and leads to oxidative stress in cells. Under ultraviolet-B radiation, the treated cells can improve their antioxidant abilities to alleviate oxidative injury. The change trends of reactive oxygen species, superoxide dismutase, peroxiclase and catalase are synchronous. These results suggest that a balance between the antioxidant system and the reactive oxygen species content may be one part of a complex stress response pathway in which multiple environmental factors including ultraviolet-B radiation affect the Survival of M. vaginatus. (C) 2009 Elsevier Masson SAS. All rights reserved.

Effect of process parameters on the morphology and nanostructure of roll-to-roll printed P3HT:PCBM thin films for organic photovoltaics

Roll-to-roll (R2R) gravure exhibits significant advantages such as high precision and throughput for the printing of photoactive and conductive materials and the fabrication of flexible organic electronics such as organic photovoltaics (OPVs). Since the photoactive layer is the core of the OPV, it is important to investigate and finally control the process parameters and mechanisms that define the film morphology in a R2R process. The scope of this work is to study the effect of the R2R gravure printing and drying process on the nanomorphology and nanostructure of the photoactive P3HT:PCBM thin films printed on PEDOT:PSS electrodes towards the fabrication of indium tin oxide (ITO)-free flexible OPVs. In order to achieve this, P3HT:PCBM blends of different concentration were R2R printed under various speeds on the PEDOT:PSS layers. Due to the limited drying time during the rolling, an amount of solvent remains in the P3HT:PCBM films and the slow-drying process takes place which leads to the vertical and lateral phase separation, according to the Spectroscopic Ellipsometry and Atomic Force Microscopy analysis. The enhanced slow-drying leads to stronger phase separation, larger P3HT crystallites according to the Grazing Incidence X-Ray Diffraction data and to weaker mechanical response as it was shown by the nanoindentation creep. However, in the surface of the films the P3HT crystallization is controlled by the impinged hot air during the drying, where the more the drying time the larger the surface P3HT crystallites. The integration of the printed P3HT:PCBM and PEDOT:PSS layers in an OPV device underlined the feasibility of fabricating ITO-free flexible OPVs by R2R gravure processes. © 2013 Elsevier B.V.

Primary succession of algal community structure in desert soil

The microbiotic crust study is among new focuses in investigating on the desertification control. Based on determination of algal crusts with different successive ages (4-, 8-, 17-, 34-, 42-year-old) and unconsolidated sand in the desert area, species composition and clustering analyses were carried out in this study. Results on successional orientation revealed that (1) the abundance of Cyanophyta, specially of Scytonema javanicum gradually decreased; (2) the abundance of Chlorophyta, Bacillariophyta and a species of Cyanophyta, Phormidium tenue increased; (3) the biodiversity increased gradually with the community succession; and (4) biomass of microalgae increased at the early stage, but decreased at the later stage due to the abundance of lichens and mosses. But, the speed of natural succession was so slow that the community-building species was still the first dominant species after 42 years, except that its dominant degree decreased just slightly. However, successive speed and trend were affected by water, vegetation coverage, terrain, time and soil physico-chemical properties as well, especially Mn content in the soil appeared to have a threshold effect.

Effect of desert soil algae on the stabilization of fine sands

Four filamentous cyanobacteria, Microcoleus vaginatus, Phormidium tenue, Scytonema javanicum (Kutz.) and Nostoc sp., and a single-celled green alga, Desmococcus olivaceus, all isolated from Shapotou (Ningxia Hui Autonomous Region of China), were batch cultured and inoculated onto unconsolidated sand in greenhouse and field experiments. Their ability to reduce wind erosion in sands was quantified by using a wind tunnel laboratory. The major factors related to cohesion of algal crusts, such as biomass, species, species combinations, bioactivity, niche, growth phase of algae, moisture, thickness of the crusts, dust accretion (including dust content and manner of dust added) and other cryptogams (lichens, fungi and mosses) were studied. The best of the five species were M. vaginatus and P. tenue, while the best mix was a blend of 80% M. vaginatus and 5% each of P. tenue, S. javanicum, Nostoc sp. and D. olivaceus. The threshold friction velocity was significantly increased by the presence of all of the cyanobacterial species, while the threshold impact velocity was notably increased only by the filamentous species. Thick crusts were less easily eroded than thin crusts, while biomass was more effective than thickness. Dust was incorporated best into Microcoleus crust when added in small amounts over time, and appeared to increase growth of the cyanobacterium as well as strengthen the cohesion of the crust. Microbial crust cohesion was mainly attributed to algal aggregation, while lichens, fungi and mosses affected more the soil structure and physico-chemical properties.

Fabrication and Infrared Optical Properties of Nano Vanadium Dioxide Thin Films

Vanadium dioxide thin films were fabricated by ion beam sputtering on Si3N4/SiO2/Si after a post reductive annealing process in a nitrogen atmosphere. X-ray Diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS) were employed to analyze the effects of post annealing temperature on crystallinity, morphology, and composition of the vanadium oxide thin films. Transmission properties of vanadium dioxide thin films were measured by Fourier transform-infrared (FT-IR) spectroscopy. The results showed that the as-deposited vanadium oxide thin films were composed of non-crystalline V2O5 and a tetragonal rutile VO2. After annealing at 400 degrees C for 2 h, the mixed phase vanadium oxide (VOx) thin film changed its composition and structure to VO2 and had a (011) oriented monoclinic rutile structure. When increasing the temperature to 450 degrees C, nano VO2 thin films with smaller grains were obtained. FT-IR results showed that the transmission contrast factor of the nano VO2 thin film was more than 0.99 and the transmission of smaller grain nano VO2 thin film was near zero at its switched state. Nano VO2 thin film with smaller grains is an ideal material for application in optical switching devices.

Assembly of side-functional monomers with inorganic nanometer particles

Monomers of methacrylate with various pi -conjugated pendants were designed and prepared in our laboratory, The monomer with suitable end-group was successfully assembled with nano-scale inorganic particles to form an orderly-aligned structure that showed special optical properties, both absorption and emission band were much red-shifted compared with the monomer, A new type of organic/inorganic hybrid materials was obtained by in situ polymerization of the assembly, The hybrid materials could also show special optical properties as the assembly, This might open a new route to tune the emission color.