Biocomposites Based on Thermoplastic Starch Reinforced with Recycled Paper Cellulose Fibers

Biocomposites sheets were prepared by compression molding from mixtures of corn starch plasticized by glycerol as matrix and cellulose fibers, extracted from used office paper, as reinforcement filler with contents ranging from 0 to 8% wt/wt of fibers to matrix. Properties of composites were determined by mechanical tensile test, differential scanning calorimetry, thermogravimetric analysis, water absorption measurement, and scanning electron microscopy. The results showed that higher fibers content raised the tensile strength and elastic modulus up to 109% and 112%, respectively, when compared to the non-reinforced thermoplastic starch (TPS). The addition of the fibers improved the thermal resistance and decreased the water absorption up to 63.6%. Scanning electron microscopy illustrated a good adhesion between matrix and fibers

Critical Thermal Maximum, Temperature Acclimation and Climate Effects on Thai Freshwater Fishes

Critical thermal maximum (CTmax) related positively with acclimation temperature between 20.0° C and a maximum that varied with the four species; Devario acrostomus, Mystacoleucus chilopterus, Barbodes binotatus and Rasbora caudimaculata, between 30.0 and 35.0° C. Highest and lowest CTmax were 39.0±1.0° C at 35.0° C acclimation for B. binotatus and 34.6±0.5° C at 20.0° C for D. acrostomus, respectively. Thermal scope at 25.0° C acclimation was lowest at 26.8° C for D. acrostomus and, higher at 29.6, 29.7 and 30.1° C for M. chilopterus, R. caudimaculata and B. binotatus, respectively. Interestingly, the majority of tropical Thai fish and temperate species examined to date showed a similar maximum thermal tolerance from the mid to high 30s that almost certainly relates to temperature induction of HSP and their production. Global temperature increases predicted for Thai rivers and others in Southeast Asia during the latter portion of the current century are likely to exceed the thermal tolerance of many indigenous fishes with important losses in species diversity

Sustainable green composites of thermoplastic starch and cellulose fibers

Green composites have gained renewed interest as environmental friendly materials and as biodegradable renewable resources for a sustainable development. This review provides an overview of recent advances in green composites based on thermoplastic starch (TPS) and cellulose fibers. It includes information about compositions, preparations, and properties of starch, cellulose fibers, TPS, and green composites based on TPS and cellulose fibers. Introduction and production of these recyclable composites into the material market would be important for environmental sustainability as their use can decrease the volume of petroleum derived plastic waste dumps. Green composites are comparable cheap and abundant, but further research and development is needed for a broader utilization

First report on genetic structure of Lobocheilos rhabdoura (Fowler, 1934) (Labeoninae, Cyprinidae) in Thailand: Insight the basic snowledge for fish breeding

Lobocheilos rhabdoura is a fish of the genus Lobocheilos in the family Cyprinidae. It is popular as an ornamental fish in Thailand and is important to fisheries and the economy. Chromosomes and chromosome markers of this species were studied by conventional staining and NOR-banding techniques. Ten male and ten female specimens were collected from the Meklong Basin, Kanchanaburi Province. The chromosomes were directly prepared from kidney tissues. The results showed that diploid chromosome was 2n = 50 and the fundamental number (NF) was 90 in all specimens. The structure karyotype consisted of 10 metacentric, 18 submetacentric, 12 acrocentric and 10 telocentric chromosomes; 10m + 18sm + 12a + 10t in both sexes without morphologically differentiated sex chromosomes. NOR positive markers were observed in regions adjacent to telomere of long arm of the largest submetacentric chromosome pair. This study provides basic knowledge of the karyotype structure of this species and this basic knowledge that can be applied for breeding of ornamental fish in the future

Seasonal Changes in Upper Thermal Tolerances of Freshwater Thai Fishes

Seasonal change inferred to climate change inevitably influences Critical thermal maximum (CTmax) of riverine fishes. In this study, we investigated CTmax as thermal tolerance for four common riverine fishes, i.e., Danio regina, Channa gachua, Rasbora caudimaculata and Mystacoleucus chilopterus, in the Kwae Noi river system in western Thailand. The acute thermal tolerance was lower in the wet season (mean river temperature ∼25 °C) and higher in the dry season (mean river temperature ∼23 °C) with medians of wet season-CTmax for those four fishes of 35.3 ± 0.4, 36.2 ± 0.5, 37.3 ± 0.5 and 37.5 ± 0.6 °C, respectively, and high values of dry season-CTmax of 37.4 ± 0.5, 38.3 ± 0.5, 38.7 ± 0.7 and 39.1 ± 0.5 °C, respectively. The variations of CTmax for all of the four species in this study, throughout the wet and dry seasons, attribute to their seasonal plasticity in response to the dynamics of thermal stress. Under climate variability and climate change with increasing the higher temperatures of air and river, and altering the habitat, R. caudimaculata and M. chilopterus had higher capacities to tolerate the acute heat stress across wet and dry seasons

Genomic Organization of Repetitive DNA Elements and Extensive Karyotype Diversity of Silurid Catfishes (Teleostei: Siluriformes): A Comparative Cytogenetic Approach

International audienceThe catfish family Siluridae contains 107 described species distributed in Asia, but with some distributed in Europe. In this study, karyotypes and other chromosomal characteristics of 15 species from eight genera were examined using conventional and molecular cytogenetic protocols. Our results showed the diploid number (2n) to be highly divergent among species, ranging from 2n = 40 to 92, with the modal frequency comprising 56 to 64 chromosomes. Accordingly, the ratio of uni- and bi-armed chromosomes is also highly variable, thus suggesting extensive chromosomal rearrangements. Only one chromosome pair bearing major rDNA sites occurs in most species, except for Wallago micropogon, Ompok siluroides, and Kryptoterus giminus with two; and Silurichthys phaiosoma with five such pairs. In contrast, chromosomes bearing 5S rDNA sites range from one to as high as nine pairs among the species. Comparative genomic hybridization (CGH) experiments evidenced large genomic divergence, even between congeneric species. As a whole, we conclude that karyotype features and chromosomal diversity of the silurid catfishes are unusually extensive, but parallel some other catfish lineages and primary freshwater fish groups, thus making silurids an important model for investigating the evolutionary dynamics of fish chromosomes