PACK CARBURIZING PADA SPROCKET SEPEDA MOTOR DENGAN MATERIAL BAJA KARBON RENDAH

High quality motorcycle sprocket with cheaper price has been achieved by giving additional processing to non original locally made sprocket such that it has an almost the same quality as the original Japanese made sprocket . The additional processing was pack carburizing which was done to the non-original sprocket, followed by quench hardening and tempering so that the quality of the non-original sprocket will be almost the same as the original sprocket. Pack carburizing was applied with active carbon as the carbon source and 10% BaCO3 as the energizer. This process was done at 950°C and one hour holding time. For heat treatment, the heating was done at 850°C for 15 minutes, followed by water quenching and tempering at 150°C for 30 minutes. The carburizing result indicated that there was a carbon penetration depth of about 1.05 mm. After tempering, an effective case depth of about 0.2 mm was achieved. The process variables for obtaining an effective case depth of original sprocket (0.2 mm) are selected by applying pack carburizing using active carbon granule with 10%wt BaCO3 as the carburizing medium, processed at 950°C for an hour, followed by water quenching from 850°C and tempering at 150°C for 30 minutes

eDNA Sebagai Metode untuk Pemantauan Biodiversitas di Kawasan Konservasi Laut Indonesia secara efektif dan efisien

Pemerintah Indonesia perlu mendorong penggunaan teknologi environmental DNA (eDNA) sebagai metode utama dalam pemantauan biodiversitas di Kawasan Konservasi Laut (KKL) guna mengatasi tantangan logistik di wilayah yang luas dan beragam. Diperlukan investasi dalam pengembangan database eDNA nasional yang mencakup sekuens referensi spesies laut Indonesia dan pelatihan serta sertifikasi bagi para pemantau eDNA untuk memastikan kualitas data yang konsisten. Monitoring dengan eDNA dapat dilakukan secara rutin dan berkelanjutan di seluruh KKL untuk mengumpulkan data yang akurat dan mendukung pengamatan tren jangka panjang dalam keanekaragaman hayati laut. Selain itu, dukungan untuk penelitian lanjutan dalam identifikasi spesies baru dan pemahaman yang lebih dalam tentang ekologi laut Indonesia melalui teknologi eDNA juga perlu diberikan. Dengan mengimplementasikan rekomendasi ini, Indonesia dapat memperkuat upaya pelestarian keanekaragaman hayati lautnya secara efektif dan efisien, menjaga keberlanjutan ekosistem laut yang kaya dan unik di negara ini

Application of GGBFS and Bentonite to Auto-Healing Cracks of Cement Paste

Cracks are caused by many factors. Shrinkage and external loading are the most common reason. It becomes a problem when the ingression of aggressive and harmful substance penetrates to the concrete gap. This problem reduces the durability of the structures. It is well known that self – healing of cracks significantly improves the durability of the concrete structure. This paper presents self-healing cracks of cement paste containing bentonite associated with ground granulated blast furnace slag. The self-healing properties were evaluated with four parameters: crack width on the surface, crack depth, tensile strength recovery, and flexural recovery. In combination with microscopic observation, a healing process over time is also performed. The results show that bentonite improves the healing properties, in terms of surface crack width and crack depth. On the other hand, GGBFS could also improve the healing process, in terms of crack depth, direst tensile recovery, and flexural stiffness recovery. Carbonation reaction is believed as the main mechanism, which contributes the self-healing process as well as the continuous hydration progress

Left-right asymmetric expression of dpp in the mantle of gastropods correlates with asymmetric shell coiling

This is the final version of the article. Available from BMC via the DOI in this record.BACKGROUND: Various shapes of gastropod shells have evolved ever since the Cambrian. Although theoretical analyses of morphogenesis exist, the molecular basis of shell development remains unclear. We compared expression patterns of the decapentaplegic (dpp) gene in the shell gland and mantle tissues at various developmental stages between coiled-shell and non-coiled-shell gastropods. RESULTS: We analyzed the expression patterns of dpp for the two limpets Patella vulgata and Nipponacmea fuscoviridis, and for the dextral wild-type and sinistral mutant lineage of the pond snail Lymnaea stagnalis. The limpets had symmetric expression patterns of dpp throughout ontogeny, whereas in the pond snail, the results indicated asymmetric and mirror image patterns between the dextral and sinistral lineages. CONCLUSION: We hypothesize that Dpp induces mantle expansion, and the presence of a left/right asymmetric gradient of the Dpp protein causes the formation of a coiled shell. Our results provide a molecular explanation for shell, coiling including new insights into expression patterns in post-embryonic development, which should aid in understanding how various shell shapes are formed and have evolved in the gastropods.This study was supported by the JSPS Grants-in-Aid for Scientific Research 15104009

Left-right asymmetric expression of dpp in the mantle of gastropods correlates with asymmetric shell coiling

Background: Various shapes of gastropod shells have evolved ever since the Cambrian. Although theoretical analyses of morphogenesis exist, the molecular basis of shell development remains unclear. We compared expression patterns of the decapentaplegic (dpp) gene in the shell gland and mantle tissues at various developmental stages between coiled-shell and non-coiled-shell gastropods. Results: We analyzed the expression patterns of dpp for the two limpets Patella vulgata and Nipponacmea fuscoviridis, and for the dextral wild-type and sinistral mutant lineage of the pond snail Lymnaea stagnalis. The limpets had symmetric expression patterns of dpp throughout ontogeny, whereas in the pond snail, the results indicated asymmetric and mirror image patterns between the dextral and sinistral lineages. Conclusion: We hypothesize that Dpp induces mantle expansion, and the presence of a left/right asymmetric gradient of the Dpp protein causes the formation of a coiled shell. Our results provide a molecular explanation for shell, coiling including new insights into expression patterns in post-embryonic development, which should aid in understanding how various shell shapes are formed and have evolved in the gastropods.ArticleEVODEVO. 4:15 (2013)journal articl

The Effect of Biofouling on Cement based Concrete Substrate: Insights from Microfouling and Macrofouling Growth

Biofouling poses a significant impact to the durability of offshore structures and vessels, yet its impact on cement-based concrete structures in marine environments remains underexplored. This study investigated biofouling growth on concrete substrates both microbial biofilms (microfouling) up to macrofouling and their effect on cement based concrete surface. The discussion is supported by a literature review to contextualize the findings. The type and growth of microorganisms forming biofilms and macrofouling are influenced by the specific marine environment, substrate characteristics, and immersion duration. These factors collectively impact concrete substrates by altering microbial community composition, biochemical activity, and mechanisms of attachment. The microfouling and macrofouling growth contribute to chemical degradation, surface roughness alteration, and the addition of weight. Such combined effects accelerate the biodeterioration and highlighting the critical need for effective mitigation strategies to enhance the durability. Protective approaches, including antifouling coatings, surface treatments, and advanced materials resistant to bioadhesion, are essential to prolong the lifespan and ensure the durability of marine concrete structures exposed to both biofilm formation and macrofouling

Microstructural and Genetic Insights Into the Formation of the “Winter Diffusion Layer” in Japanese Pearl Oyster Pinctada fucata and Its Relation to Environmental Temperature Changes

金沢大学国際基幹教育院 GS教育系Phenotypic plasticity in molluscan shell microstructures may be related to environmental changes. The “winter diffusion layer,” a shell microstructure of the Japanese pearl oyster Pinctada fucata, is an example of this phenomenon. In this study, we used P. fucata specimens with shared genetic background to evaluate the seasonal plasticity of shell microstructures, at molecular level. To detect the seasonal changes in shell microstructure and mineral composition, shells of multiple individuals were periodically collected and analyzed using scanning electron microscopy and Raman spectrophotometry. Our observations of the winter diffusion layer revealed that this irregular shell layer, located between the outer and middle shell layers, had a sphenoid shape in radial section. This distinct shape might be caused by the internal extension of the outer shell layer resulting from growth halts. The winter diffusion layer could be distinguished from the calcitic outer shell layer by its aragonitic components and microstructures. Moreover, the components of the winter diffusion layer were irregular simple prismatic (the outer and inner sublayers) and homogeneous structures (the middle sublayer). This irregular formation occurred until April, when the animals resumed their “normal” shell formation after hibernation. To check for a correlation between gene expression and the changes in microstructures, we conducted qPCR of seven major biomineralization-related shell matrix protein-coding genes (aspein, prismalin-14, msi7, msi60, nacrein, n16, and n19) in the shell-forming mantle tissue. Tissue samples were collected from the mantle edge (tissue secreting the outer shell layer) and mantle pallium (where the middle shell layer is constructed) of the same individuals used for microstructural observation and mineral identification that were collected in January (winter growth break period), April (irregular shell formation period), and August (normal shell formation period). Statistically significant differences in gene expression levels were observed between mantle edge and mantle pallium, but no seasonal differences were detected in the seasonal expression patterns of these genes. These results suggest that the formation of the irregular shell layer in P. fucata is caused by a currently unknown genetic mechanism unrelated to the genes targeted in the present study. Further studies using big data (transcriptomics and manipulation of gene expression) are required to answer the questions herein raised. Nevertheless, the results herein presented are essential to unravel the intriguing mystery of the formation of the winter diffusion layer, which may allow us to understand how marine mollusks adapt or acclimate to climate changes. Copyright © 2022 Sato, Setiamarga, Yonemitsu and Higuchi

Polymer composition of microplastics in marine organisms across trophic levels

Microplastic contamination poses a growing threat to marine ecosystems and human health, with impacts observed across all trophic levels. This study reviews 16 empirical articles to extract data on the chemical composition and morphological features of microplastic particles found in marine organisms. The analysis focuses on herbivorous, omnivorous, and carnivorous taxa, emphasizing polymer diversity and accumulation patterns. Polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) were the most commonly detected polymers across all trophic levels, with fiber as the dominant morphological form. Polymer diversity tended to increase in higher trophic levels, suggesting potential bioaccumulation. The color and shape of particles further varied across species, with blue and black fibers being the most frequent. The findings underline the need for consistent reporting of polymer data and reinforce the importance of integrating chemical composition analysis in microplastic monitoring strategies

Allelic Expression Changes in Medaka (Oryzias latipes) Hybrids between Inbred Strains Derived from Genetically Distant Populations

Variations in allele expressions between genetically distant populations are one of the most important factors which affects their morphological and physiological variations. These variations are caused by natural mutations accumulated in their habitats. It has been reported that allelic expression differences in the hybrids of genetically distant populations are different from parental strains. In that case, there is a possibility that allelic expression changes lead to novel phenotypes in hybrids. Based on genomic information of the genetically distant populations, quantification and comparison of allelic expression changes make importance of regulatory sequences (cis-acting factors) or upstream regulatory factors (trans-acting modulators) for these changes clearer. In this study, we focused on two Medaka inbred strains, Hd-rR and HNI, derived from genetically distant populations and their hybrids. They are highly polymorphic and we can utilize whole-genome information. To analyze allelic expression changes, we established a method to quantify and compare allele-specific expressions of 11 genes between the parental strains and their reciprocal hybrids. In intestines of reciprocal hybrids, allelic expression was either similar or different in comparison with the parental strains. Total expressions in Hd-rR and HNI were tissue-dependent in the case of HPRT1, with high up-regulation of Hd-rR allele expression in liver. The proportion of genes with differential allelic expression in Medaka hybrids seems to be the same as that in other animals, despite the high SNP rate in the genomes of the two inbred strains. It is suggested that each tissue of the strain difference in trans-acting modulators is more important than polymorphisms in cis-regulatory sequences in producing the allelic expression changes in reciprocal hybrids

Utilization of high-volume fly ash in pervious concrete mixtures for mangrove conservation

In environmental conservation, mangrove forests play a crucial role. Retransplanting mangrove propagules, however, faces challenges, and success rates are notably low. Achieving an optimal protector for propagules, balancing strength without impeding growth, is challenging. Mangrove propagules require a temporary protector with an optimal balance, neither too weak nor too strong, to shield them from current waves which is difficult. We propose using pervious concrete pots with high-volume fly ash activated with low NaOH concentrations. The investigation focuses on the influence of the mixing procedure on workability, compressive strength, and mineral composition. The novel discovery in this study is the specific sequence of stirring the ingredients using an alkali activator, which adds an interesting dimension to the research. It is recommended to adopt Sequence 2 in pervious concrete production, where NaOH dissolved FA in the mixture forming albite as N-A-S-H gel product. It surely enhanced both workability and the strength confirming uniform application processes. The two recommended variants, PFS-60 and PFBS-50, effectively utilize coal ash, meeting the target compressive strength range of 3–5 MPa and providing support for mangrove pots over a 3–4 year period. Notably, both compositions maintained consistent mechanical properties during exposure to tidal conditions for 240 days.They exhibit high permeability (694 liter/m²/minute), facilitating efficient water passage without sediment entrainment