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Nanochitin was developed to effectively utilize crab shells, a food waste product, and there is ongoing research into its applications. Short nanowhiskers were produced by sonicating partially deacetylated nanochitin in water, resulting in a significant decrease in viscosity due to reduced entanglement of the nanowhiskers. These nanowhiskers self-assembled into a multilayered film through an evaporation technique. The macro- and nanoscale structures within the film manipulate light, producing vibrant and durable structural colors. The dried cast film exhibited green and purple stripes extending from the center to the edge formed by interference effects from the multilayer structure and thickness variations. Preserving structural colors requires maintaining a low ionic strength in the dispersion, as a higher ionic strength reduces electrostatic repulsion between nanofibers, increasing viscosity and potentially leading to the fading of color. This material's sensitivity to environmental changes, combined with chitin's biocompatibility, makes it well-suited for food sensors, wherein it can visually indicate freshness or spoilage. Furthermore, chitin's stable and non-toxic properties offer a sustainable alternative to traditional dyes in cosmetics, delivering vivid and long-lasting color. [ABSTRACT FROM AUTHOR]

Chitin is the second most abundant biopolymer in the world after cellulose and commonly found in crustaceans. It is also the most abundant natural nitrogen-containing polysaccharide. The challenge in separation of chitin directly from snow crab (Chionoecetes opilio) shells is that the solvent used must be versatile in removing calcium carbonate and protein while also being efficient, environmentally friendly, and cost-effective. In this study, chitin was extracted from snow crab shells using a DES consisting of TEBAC and lactic acid. DES successfully removed minerals and proteins, with a deproteinization rate of 95.51% and a decalcification rate of 96.41%, while the purity of chitin was 91.15% and the yield was 21.31%. Furthermore, the extracted chitin has large pores on its surface, making it an ideal matrix for biomedical materials. This study provides an environmentally friendly and cost-effective solution for the utilization of crustacean waste using multifunctional DES. [ABSTRACT FROM AUTHOR]

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To investigate the effects of predation by the paddle crab Charybdis japonica on the culture and survival of scallops (Mizuhopecten yessoensis) during bottom culture, we investigated the behavioral characteristics of three sizes (small, medium, and large) of scallops in response to exposure to crabs. We found that scallops escaped from crab predation by continuous shell closure or movement. Shell closure force increased with scallop size, and scallops of the same size that were stimulated by the presence of crabs closed their shell more frequently than control scallops. We also measured the activities of superoxide dismutase, catalase, arginine kinase, and octopine dehydrogenase in the gill, adductor muscle, and mantle of scallops before and after exposure to predation. Tissues that showed significant differences between control and test specimens were selected for deep sequencing of the transcriptome to identify and validate the key genes that were sensitive to predation. We found that when M. yessoensis is stimulated by the presence of predators, its behavioral characteristics and related physiological and ecological indexes undergo significant changes. The results are relevant for developing specifications for M. yessoensis seedling casting during bottom culture. [ABSTRACT FROM AUTHOR]

Based on a long-term dataset of species composition and infestation levels of associated organisms on the invasive Barents Sea red king crab, a multivariate analysis was conducted to determine the contributions of biotic and abiotic factors to the fouling community structure. Results indicate that host size and exoskeleton age were the most significant factors for diversity indices and infestation intensity. Abiotic factors played a lesser role in the formation of fouling communities. Temperature conditions during the mass molting periods were found to have significant effects, apparently acting as a trigger for the primary settlement of crab shells by benthic organisms. Our data not only provide new insights into the formation of fouling communities of decapod crustaceans, but also provide valuable information for further studies on the adaptation process of the red crab to the conditions of the Barents Sea. [ABSTRACT FROM AUTHOR]

Two western Pacific states — the Solomon Islands and Papua New Guinea (PNG) — experimented with unusual and ambitious reforms aimed at strengthening political parties in the new millennium. In this paper, we look at what those laws entailed and how they worked in practice. In both cases, we find that unforeseen repercussions dominated. In PNG, the new laws encouraged candidates who formerly contested as independents to now nominate as members of microscopic one‐ or two‐member parties whereas in the Solomon Islands many formerly party‐affiliated candidates adjusted by contesting as independents. In PNG, the law was one of a range of devices aimed at strengthening incumbent governments, but money politics and manipulation of parliamentary procedure proved more significant. Core anti‐defection provisions in the new law were ruled unconstitutional in 2010, but other still valid clauses preserved an advantage for the "largest party" in government formation. In the Solomon Islands, the law created a shadow world of free‐floating individuals able to switch at liberty between formally constrained hermit crab shell parties. In neither country did these laws succeed in strengthening party systems. [ABSTRACT FROM AUTHOR]

Coagulation/Flocculation (C/F) process aims to efficiently eliminate turbidity, TSS, COD, BOD, toxic metals, phosphates, and UV254nm from wastewater. Both natural and synthetic coagulants, used alone or in conjunction with flocculants, play crucial roles in this treatment. This review summarizes recent trends in coagulants for wastewater treatment, highlighting a wide array of inorganic and organic coagulants that have demonstrated significant efficacy based on reviewed studies. Notably, Crab Shell Bio-Coagulant (CS) excels in turbidity remov5al, achieving a remarkable 98.91% removal rate, while oak leaves protein shows superior performance in TSS and COD removal. Synthetic inorganic coagulants like PALS, PSiFAC1.5:10:15, and PAPEFAC1.5-10-15 demonstrate outstanding turbidity removal rates, over 96%. POFC-2 coagulant stands out for efficiently removing TSS and COD from domestic wastewater, achieving up to 93% removal for TSS and 89% for COD. Moreover, the utilization of FeCl3 as an inorganic coagulant alongside chitosan as an organic flocculant shows promise in reducing turbidity, COD, and polyphenols in wastewater from vegetable oil refineries. PE-2, a novel organic coagulant, demonstrates exceptional efficacy in eliminating turbidity, TSS, COD, and BOD from sugar industry wastewater. Chitosan shows effectiveness in removing TOC and orthophosphates in brewery wastewater. Additionally, CTAB shows high efficiency in removing various toxic metal ions from wastewater. The hybrid coagulants: PAAP0.1,0.5 and PPAZF accomplish exceptional turbidity removal rates, approximately 98%. [ABSTRACT FROM AUTHOR]

The snow/pink crab (Chionoecetes opilio) and Northern shrimp (Pandalus borealis) are widely distributed in the North Atlantic Ocean. During processing/consumption, about 80% of the harvest is discarded as processing waste, which is a rich source of protein, chitin, minerals, and carotenoids. This study, for the first time, investigated the proximate composition and individual amino acids, minerals, and carotenoids from different body parts (carapace, shoulder, claw, tip, and leg) of snow crabs and shrimp shells. Shrimp proteins were found to be abundant and well-balanced in their amino acid composition. Compared to shrimp shells, a lower content of amino acids was found in the snow crab, depending on the part of the shell used. Moreover, crab shells, mainly crab claws, contained a higher (p < 0.05) level of chitin compared to shrimp shells. Seven micro-elements (Mn, Fe, Cu, Zn, As, Ba, and Ce) and six macro-elements (Ca, Na, K, Mg, P, and Sr) were identified using inductively coupled plasma-mass spectrometry (ICP-MS). Among them, calcium and iron were higher in crab carapaces (p < 0.05), followed by shrimp shells and other crab shell segments. Additionally, shrimp and crab carapaces contained a significant level of carotenoids, and these were mainly composed of astaxanthin and its mono- and diesters, along with zeaxanthin, astacene, canthaxanthin, and lutein. Thus, this investigation provides detailed information to allow upcycling of shellfish waste and addresses the knowledge gap concerning the availability of various nutrients in different crab sections and shrimp shells. [ABSTRACT FROM AUTHOR]

Developing wound dressings with healing properties is a crucial requirement, especially in developing countries. In this research work, chitosan is extracted from Monomia gladiator crab shells for the first time to fabricate a novel wound dressing. The prepared chitosan (CS) is blended with silk sericin (SS), polyvinyl alcohol (PVA), and silver nanoparticles (AgNPs) in three different ratios of PVA:CS:SS (100:0:0), PVA:CS:SS (80:10:10) – AgNPs, and PVA:CS:SS (50:25:25) – AgNPs to produce nanofibers. The developed nanofibers were analyzed under a scanning electron microscope (SEM), tensile testing, and antibacterial activity to study their fiber size, tensile strength, and bactericidal properties, respectively. The cell viability test against L929 cells demonstrates that the prepared wound dressing is noncytotoxic and facilitates cell proliferation. In vivo research on a full‐thickness excision wound model states that the incorporation of SS, CS, and AgNPs into the PVA introduces a novel multifunctional advancement in wound dressing, offering versatile benefits by promoting reepithelialization and collagen deposition. In summary, PVA:CS:SS(50:25:25)‐AgNPs can serve as an excellent wound dressing. Highlights: CS extracted from Monomia gladiator crab shells.The extracted CS is blended with SS, PVA and AgNPs to fabricate nanofibers.The inclusion of CS and SS exhibited good tensile strength and antibacterial activity.PVA:CS:SS(50:25:25)‐AgNPs served as an excellent wound dressing. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel PENG using PVDF blended with crab shell powder (CS-NFs) was fabricated via electrospinning for flexible energy harvesting. • Enhanced piezoelectric performance is achieved due to the piezoelectric properties of chitin and its interaction with PVDF β-phase. • Incorporation of 1.5 wt.% CS-NFs improved the output, generating up to 19 V under mechanical deformation for energy harvesting. • This PENG can monitor respiratory and power low-energy devices, offering a sustainable, biocompatible, and eco-friendly sensors. Wearable piezoelectric nanogenerators (PENGs) are increasingly significant in healthcare and energy harvesting applications due to their ability to convert mechanical energy into electrical signals. In this study, we developed PENGs by incorporating crab shell powder (CS-NFs) into electrospun polyvinylidene fluoride (PVDF) nanofibers to enhance their piezoelectric properties. The PVDF-CS-NFs (PC-NFs) composites were evaluated for structural, thermal, and piezoelectric performance. The 1.5 wt% CS-NFs composite exhibited a notable improvement, with a maximum output voltage of 19 V under mechanical deformation, significantly higher than pristine PVDF NFs. Furthermore, the device demonstrated excellent sensitivity in real-time respiratory monitoring when applied to various body locations, including the chest, throat, and mask. Additionally, the PC-NFs-based PENGs were capable of charging a 2.2 µF capacitor to 2 V within 180 s and powering 56 LEDs. These results underscore the potential of using sustainable crab shell waste in biocompatible, eco-friendly piezoelectric devices for wearable sensors and energy harvesting applications. [ABSTRACT FROM AUTHOR]

Crab is an exotic marine fishery commodity whose demand is increasing significantly in Indonesia. However, the industry also produces much waste in the form of crab shells, reaching 52.59% of its total weight. This waste (often called by-product) can be processed into several products with economic value such as chitosan, liquid organic fertilizer, and animal feed. This study assesses the environmental impact of crab shells processed into chitosan, liquid organic fertilizer, and animal feed. The study was carried out using the Life Cycle Assessment (LCA) approach with cradle-to-gate scope. The environmental impacts were observed consisting of some aspects such as Global Warming Potentials (GWP), Acidification Potentials (AP), Eutrophication Potentials (EP), and Cumulative Energy Demand (CED). The three-alternative utilization of crab shells produces environmental impacts resulting from fishing, transportation, and processing of the crab shells into these products. Afterward, the results of this study indicate that the crab shells processed into liquid fertilizer have the highest emission according to the GWP, AP, and CED values compared to the other by-product alternatives (i.e., chitosan and fertilizer). Whilst, the highest EP is produced by the processing of CS-based animal feed. These results can potentially become a consideration in making environmental policy by the local government, especially in Karawang Region.

"In Dialogue with the Mahābhārata" by Brian Black is a book that explores the significance of dialogues in the epic Mahābhārata. The author provides commentary on key dialogues in the epic, offering insights into their philosophical and moral implications. The book is useful for scholars interested in the epic, as well as teachers and students looking to engage in discussions about complex episodes. Black argues that by studying the dialogues in the Mahābhārata, readers can learn to think critically about their own lives and gain a deeper understanding of existential and normative dimensions. [Extracted from the article]

The detection technology of soft-shell crab breaks the traditional soft-shell crab breeding method. Conventional farming practices rely heavily on human labor for the identification of soft-shell crab birth, and manual inspections are prone to issues such as delayed and inaccurate results. In this paper, we propose an improved high-precision detection algorithm called YOLOF based on YOLOv5. This algorithm achieves precise detection of soft-shell crab. To address the absence of soft-shell crab detection datasets on the internet, this paper establishes the Crab Molting Detection Dataset (CMP) for the purpose of training neural networks. The detection algorithm has undergone several improvements in the following aspects: the introduction of the FassterNetT1 feature extraction network to replace the original CSPDarknet53 backbone network significantly reduces model complexity and computational overhead; The incorporation of an additional auxiliary prediction feature layer of size 5 × 5 enhances the model's adaptability for detecting various molting states of crabs; the activation function GeLU was introduced, to enable the model to extract features more smoothly and reduce information loss during feature extraction; additionally, the definition of Mixed Convolution (MConv) was proposed to replace Partial Convolution (PConv) in the FasterNet Block. MConv exhibits comparable speed to PConv while possessing high-performance convolution capabilities, allowing the backbone network to extract more abundant semantic information; The introduction of the Content-Aware ReAssembly of FEatures (CARAFE) operator, a universal upsampling algorithm, enhances the extraction of crab shell contour information, thereby improving the model's accuracy in detecting soft-shell crab; addition of an Explicit Visual Center (EVC) in the network neck to strengthen the model's grasp of long-range dependencies and critical information in the image, enhancing the model's robustness. The experimental results demonstrate that YOLOF achieves a 5.4% improvement in mean average precision compared to the original YOLOv5s algorithm. The average precision for the classes "shedding_crab" and "end_unshell" increased by 1.7% and 16.3% respectively. The model running speed is 28FPS, indicating that the proposed YOLOF algorithm can accurately and efficiently identify the molting states of crabs. This study provides the theoretical foundation and technical support for the realization of an automated system for soft-shell crab cultivation. [ABSTRACT FROM AUTHOR]

A recent population collapse of eastern Bering Sea (EBS) snow crab (Chionoecetes opilio) led to the first-ever closure of the snow crab fishery in 2022. The population collapse, caused, in part, by unprecedented warming, was preceded by peaks in juvenile snow crab density (2018) and bitter crab disease (BCD, Hematodinium sp.; 2016), a fatal crustacean disease. Annual bottom trawl surveys in the EBS show high year-to-year spatiotemporal variation in BCD-infected crab, yet it remains unclear what ecological drivers might explain the variation. We used statistical models of BCD presence/absence to examine the relative importance of intrinsic and extrinsic factors as drivers of BCD. We found a dome-shaped relationship between temperature and BCD presence, and results suggest that 2–4°C bottom temperatures are more likely to support BCD. Matching with past work across the globe, we find that stations with high population density of small, new shell crab are most likely to be BCD-positive. While our work highlights the challenges of disease monitoring in the EBS, our results indicate that indirect management measures related to snow crab rebuilding and recruitment may be more appropriate than directed fisheries management in mitigating BCD impacts. [ABSTRACT FROM AUTHOR]

Chitosan is a good adsorbent but has poor effectiveness against some dyes. Therefore, in this study, we synthesized composite materials of prepared crab shell chitosan with ZnO and PVA to improve adsorption efficiency. The ZnO/CTS and ZnO/PVA/CTS composites were synthesized by dissolving the components into a solution with the help of ultrasound and hydrothermally neutralizing it for 3 h. The obtained composites and crab shell chitosan were characterized by methods such as GPC, FTIR, XRD, and SEM. Adsorption experiments were conducted in batch form and only sampled once under each condition. The results showed the molecular weight of crab shell chitosan is around 105 g/mol and quite homogenous in size, and the embedded nanorod-like ZnO in the composite is around 200 nm in sizes. The adsorption of the dyes Indigo Carmine (IC), Alizarin Yellow (AY), and Thymol Blue (TB) onto the composites was highest compared to the single adsorbent and ranked in descending order: ZnO/CTS+AY > ZnO/PVA/CTS+IC > ZnO/CTS+IC > ZnO/PVA/CTS+AY > ZnO/CTS+TB > ZnO/PVA/CTS+TB, which corresponds to qmax of 285.7 mg/g, 227.3 mg/g, 208.3 mg/g, 188.7 mg/g, 60.6 mg/g, and 50.3 mg/g, respectively. In addition, the adsorption kinetics of all cases followed the pseudo-second-order adsorption model, it implies that the rate of adsorption is proportional to the square of the number of unoccupied sites. [ABSTRACT FROM AUTHOR]

In recent years, natural fiber-reinforced hybrid composites have been utilized in many applications because of their lower cost, biodegradability, and low density. The aim of this research is to convert crab shell waste into an effective reinforcement in jute/carbon fiber hybrid composites. Various weight percentages of crab shell powder (0%, 1%, 3%, 5%, and 7%) were used to prepare crab shell powder hybrid composites. The performance of the crab shell powder hybrid composites was evaluated by preparing the specimens to conduct tensile, flexural, impact, and hardness tests as per ASTM standards. The results show that the inclusion of 5% crab shell powder displayed a better enhancement in the properties of the hybrid composite compared to other weight percentages. The tensile, flexural, and impact strengths of the 5% crab shell powder hybrid composite increased by 21%, 52%, and 50%, respectively. Also, the hardness of the hybrid composite was enhanced by 33%. Scanning electron microscopy (SEM) tests were conducted on the tensile-fractured specimen surfaces, and their morphology and structure confirmed the presence of a well-bonded interface between the fiber and matrix. Differential Scanning Calorimetry (DSC) and Thermogravimetry (TG) analysis have shown that the crystallization behavior and thermal stability of the composite were enhanced with the inclusion of crab shell powder. The presence of crab shell powder in the hybrid composite was identified using SEM with Energy-Dispersive X-ray Spectroscopy (EDS). [ABSTRACT FROM AUTHOR]

Natural chitin/CaCO3 (ChCC) complex derived from crab shell was modified and used to fabricate an organic/inorganic complex filler to enhance the optical and mechanical properties of polylactic acid (PLA) biocomposite. Crab shell was treated with NaOH to remove proteins and pulverized to produce ChCC microparticles having flake-like shape. The presence of CaCO3 in ChCC enhanced the hydrophobicity of the microparticles after treatment with fatty acids. The ChCC-filled PLA composite films prepared via melt extrusion displayed good optical properties without harsh discoloration (ΔE of 0.9%). In contrast, the film filled only with chitin showed high ΔE of 15% at same filler content, which is not commonly observed in biopolymer-filled biocomposites. Also, the ChCC-filled film exhibited higher mechanical properties, with an 8% increase in tensile strength compared to PLA, while the chitin-filled film showed a decreased tensile strength of 6% than PLA, which was attributed to the improved compatibility between the hydrophobic ChCC and the PLA matrix. The inexpensive preparation of ChCC and its application as a biocomposite filler is an attractive use of crab shell waste. [ABSTRACT FROM AUTHOR]

The fabrication of a biodegradable polycaprolactone (PCL)/hydroxyapatite (HAp) scaffold prepared from local waste blue crab shells (Portunus pelagicus) by melt spinning method was investigated. The effect of different KH2PO4 concentrations on the physico‐chemical properties of HAp is evaluated. Furthermore, the influence of PCL/HAp ratios on mechanical strength and particle size distribution is reported. The formation of HAp is confirmed by Infrared (IR) spectroscopy and X‐ray diffraction (XRD). The biocompatibility of the PCL/HAp composites was evaluated using MTT assay and mechanical tests. The results reveal that the increase in KH2PO4 concentration contributed to the higher yield of HAp. However, the crystal and particle sizes are relatively invariable. SEM micrograph shows that the HAp introduction into PCL improves the material's porosity. Moreover, adding 10 % HAp into the PCL matrix significantly improved the mechanical strength of the filament compared to commercial PCL. MTT assay exhibits above 90 % cell viability, implying that the prepared PCL/HAp composite is non‐toxic and biocompatible with artificial bone replacement. After all, this study demonstrates that PCL/HAp filament derived from local blue crab waste is highly promising as a bone scaffolding material. [ABSTRACT FROM AUTHOR]

Crabs of the genus Charybdis are some of the world’s most aggressive and voracious marine invasive crustaceans. They are found in a wide variety of ecosystems in the Red Sea. Their near ubiquity in diverse marine habitats, however, makes them a possible resource for novel marine-derived bioactive products. To provide an important insight into the potential for C. natator as a beneficial product, its shell methanolic extract was chromatographically analyzed for identification of potential bioactive ingredients. Additionally, two different doses, i.e. a low and a high dose, of this extract were tested for their ability to protect against copper-induced oxidative stress and proinflammatory response in adult zebrafish Danio rerio. Gene expression levels of transcripts of proinflammatory mediators, i.e. nf-κβ and tnf-α; antioxidant enzymes, i.e. sod, cat, and gpx; and lipid-metabolizing enzymes, i.e., acox1 and fasn, were determined. The results showed that C. natator shell is rich in potential bioactive metabolites, including diverse unsaturated fatty acids, alkanes, flavonoids, and phenolic acids. Most antioxidant and proinflammatory transcripts in the protected groups were restored to levels that were lower than those in the CuSO4-stressed group. The low dose showed special success in inducing these effects. Also, the low-dose-protected group showed significantly elevated acox1 and decreased fasn, suggesting the capability of crab shell extract at a low dose to assist lipolysis and inhibit lipogenesis. The abundant presence of saturated fatty acids in the shell extract can be the reason for the inadequacy of the high dose to promote the antioxidant and anti-inflammatory activities. These results suggest that there is a potential to develop therapeutic industrial uses for C. natator shell, instead of considering it as a discard. Its wealth of bioactive metabolites may contribute to the market for natural products to combat inflammatory and oxidative stress, the origin of many diseases in the modern world. [ABSTRACT FROM AUTHOR]

The Chinese mitten crab (Eriocheir sinensis), a species unique to Chinese aquaculture, holds significant economic value in the seafood market. In response to increasing concerns about the quality and safety of Chinese mitten crab products, the high traceability costs, and challenges for consumers in verifying the authenticity of individual crabs, this study proposes a lightweight individual recognition model for Chinese mitten crab carapace images based on an improved MobileNetV2. The method first utilizes a lightweight backbone network, MobileNetV2, combined with a coordinate attention mechanism to extract features of the Chinese mitten crab carapace, thereby enhancing the ability to recognize critical morphological features of the crab shell while maintaining the model's light weight. Then, the model is trained using the ArcFace loss function, which effectively extracts the generalized features of the Chinese mitten crab carapace images. Finally, authenticity is verified by calculating the similarity between two input images of Chinese mitten crab carapaces. Experimental results show that the model, combined with the coordinate attention mechanism and ArcFace, achieves a high accuracy rate of 98.56% on the Chinese mitten crab image dataset, surpassing ShuffleFaceNet, MobileFaceNet, and VarGFaceNet by 13.63, 11.1, and 6.55 percentage points, respectively. Moreover, it only requires an average of 1.7 milliseconds per image for verification. While maintaining lightness, this model offers high efficiency and accuracy, offering an effective technical solution for enhancing the traceability of Chinese mitten crab products and combating counterfeit goods. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HA) is a bio ceramic commonly utilized in bone tissue engineering due to its bioactive and osteoconductive properties. Crab shells are usually disregarded as waste material despite their significant CaCO3 content, and have not been widely utilized in the synthesis of HA. This study aims to synthesize and analyze HA derived from crab shells using the hydrothermal method with different durations of holding time. This study utilized precipitated calcium carbonate (PCC) derived from crab shells. With a hydrothermal reactor set at 160°C and varying holding times of 14 (HA_14), 16 (HA_16), and 18 (HA_18) h, a PCC and (NH4)2HPO4 mixture was used to synthesize HA. The synthesis results were analyzed using scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) tests. This study has accomplished the synthesis of HA from crab shells. Nonetheless, the final product of synthesis still contained CaCO3 as an impurity. The prolonged hydrothermal holding time of 14 to 18 h resulted in a reduction of impurities while increasing the percentage of crystal weight and crystallite size of HA. Specimen CH_18 is the best-quality product generated in this study. This specimen produced HA with the highest percentage of crystal weight and crystallite size compared to the other specimens. Furthermore, specimen CH_18 exhibited the lowest concentration of impurities. The Ca/P ratio in this specimen was also the closest to 1.67. The Ca/P ratio, crystallite size, and crystal weight percentage of this specimen are 1.54, 19.06 nm, and 99.1%, respectively. [ABSTRACT FROM AUTHOR]

The purpose of this study is to isolate high-efficiency total petroleum hydrocarbons (TPHs) degrading bacteria and construct different biomass-based biochar immobilized compound bacteria (ICB), and evaluate the degradation effect of ICB in TPHs contaminated soil. High-efficiency degrading bacteria Pseudomonas sp. E and Ochrobactrum intermedium H were screened from TPHs contaminated soil. Strain E and H exhibited synergistic effect of degradation, the optimal ratio of combination was 2 : 1, and the degradation rate is about 85.97% for 5 d, which was significantly better than that of single strain. The compound bacteria were immobilized with maize straw, crab shells, and sawdust biochar. Tests with three different ICB were performed with TPHs contaminated soil to assess the removal of TPHs and enzyme activity of soil during 50 days, treatment. The order of degradation rate of TPHs in each treatment group was as crab shells ICB (78.3%)>maize straw ICB (75.7%)>sawdust ICB (65.3%) >control group (9.83%). Crab shells ICB exhibited highest biodegradation efficiency and the shortest half-life (22.21 d). In addition, Crab shells ICB significantly enhanced the activities of catalase and dehydrogenase, and soil fertility increased significantly, possess application potential in soil in situ remediation. [ABSTRACT FROM AUTHOR]

Graphene-based hybrids such as carbon nanotube/graphene nanosheet (CNT/GNS), carbon nanofiber/graphene nanosheet (CNF/GNS), and CNF-CNT/GNS have attracted extensive attention in energy-related applications due to their excellent properties. The selective synthesis of GNS-based hybrids usually relies on the precise design of metal catalysts and multiple tedious processes. Here, a facile one-step synthesis of GNS-based hybrids was successfully performed by chemical vapor deposition (CVD) on waste bio-shell derived catalysts without the addition of extra metal components, and GNS-based hybrids were selectively synthesized through the hydration and dehydration (H-D) treatment of catalysts. When eggshells were calcined at high temperature, the obtained E-CaO catalyst only synthesized GNSs. After E-CaO was treated by the H-D method, the obtained E-CaO-H-1 catalyst grew CNF/GNS. E-CaO-H-2 catalyst was further prepared by the H-D treatment of E-CaO-H-1, which produced CNF-CNT/GNS. Multiple characterizations of catalysts demonstrated that the high-temperature calcination of eggshells led to the aggregation of CaO and incorporation of Fe into CaO lattices, and thus only GNSs were synthesized on CaO. However, after the H-D treatment of E-CaO, the Fe element was released from CaO lattices and the surface area of CaO enhanced with the decrease of particle size, leading to the dispersion of Fe oxides on the CaO surface, and Fe particles were subsequently formed during the CVD synthesis, which synthesized CNFs on GNS. Further, with the size reduction of Fe particles after the second H-D treatment of the catalyst, smaller Fe particles facilitated the CNT growth, leading to the production of CNF-CNT/GNS. Similarly, the catalysts formed by calcination of other bio-shells (oyster shells, shrimp shells, and crab shells) only synthesized GNSs, whereas these catalysts after H-D treatment produced CNF-CNT/GNS with enhanced carbon yields. This study offers a new method for utilizing the metal species in waste bio-shells for the facile production of structurally tunable GNS-based hybrid materials. [ABSTRACT FROM AUTHOR]

In the presented work, the effect of hydroxyapatite/polycaprolactone (HAp/PCL) ratio and the immersion/withdrawal speed on the corrosion rate and antibacterial properties of Ti-6Al-4V ELI dental implant coating was investigated. Ti-6Al-4V ELI implants are coated with different HAp-PCL ratios and immersion speeds. The functional groups of product hydroxyapatite were confirmed using the HAp standard JCPDS no. 09-0432, with crystallinity of 88.32% and ratio Ca/P at 2.12. The result shows that the higher concentrations of hydroxyapatite result in the decrease of corrosion rate and increased antibacterial activity reflected in larger inhibition zones. Additionally, the higher immersion and withdrawal speeds during dip-coating lead to lower corrosion rates. Furthermore, decreased corrosion rates may enhance the antibacterial properties of HAp-PCL coatings. These results demonstrate that the HAp/PCL composite can be considered as a prospective candidate for dental implant Ti-6Al-4V ELI coating. [ABSTRACT FROM AUTHOR]

The development of novel drug candidates for treating microbial infections and cancer turns into a challenging task. The biopolymer-based nanomaterials have gained popularity for their effective roles in the pharmaceutical sector. The present investigation aims to valorize crab shell wastes to extract chitosan. The obtained (chitosan) biomass was utilized to synthesize chitosan-zinc oxide nanoparticles (Ch-ZnO-NPs). The nanomaterial characterization was achieved by a variety of physicochemical techniques including UV, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), elemental analysis, and High-resolution transmission electron microscopic (HR-TEM) examination. The synthesized nanomaterials have a particle size range of 35-80 nm and are more stable with a zeta potential value of (-40.78) mv. Additionally, the designed nanomaterials were utilized to evaluate the biological efficiency. The minimal inhibitory concentration value of Ch-ZnO-NPs was observed as 10 &#181g/mL. The designed nanomaterials significantly reduced the growth of Vibrio alginolyticus and Bacillus cereus and inhibited biofilm formation. The synthesized Ch-ZnO-NPs unveiled cytotoxic effects on A549 cells with an IC50 (half-maximal inhibitory concentration) of 20 µg/mL. Furthermore, substantial increase in cell death was noticed in A549 cells treated with Ch-ZnO-NPs. Consequently, this investigation concludes that Ch-ZnO-NPs may act as a biomedicine. [ABSTRACT FROM AUTHOR]

A newly isolated amylolytic strain was identified as Bacillus cereus spH1 based on 16S and 16-23S gene sequencing (Accession numbers OP811441.1 and OP819558, respectively), optimization strategies, using one variable at time (OVAT) and Plackett–Burman design, were employed to improve the alpha-amylase (α-amylase) production. Condition inferred revealed that the optimal physical parameters for maximum enzyme production were 30 °C, pH 7.5, and 12 h of incubation, using tryptone, malt extract, orange (Citrus sinensis) peels, crab (Portunus segnis) shells, calcium, and sodium chloride (NaCl) as culture medium. The full factorial design (FFD) model was observed to possess a predicted R2 and adjusted R2 values of 0.9788 and 0.9862, respectively, and it can effectively predict the response variables (p = 0). Following such efforts, α-amylase activity was increased 141.6-folds, ranging from 0.06 to 8.5 U/mL. The ideal temperature and pH for the crude enzyme activity were 65 °C and 7.5, respectively. The enzyme exhibited significant stability, with residual activity over 90% at 55 °C. The maltose was the only product generated during the starch hydrolysis. Moreover, the Bacillus cereus spH1 strain and its α-amylase were used in the treatment of effluents from the pasta industry. Germination index percentages of 143% and 139% were achieved when using the treated effluent with α-amylase and the strain, respectively. This work proposes the valorization of agro-industrial residues to improve enzyme production and to develop a green and sustainable approach that holds great promise for environmental and economic challenges. [ABSTRACT FROM AUTHOR]

Millions of tons of crab shells are annually discarded. Crab shells contain several valuable compounds such as chitosan that can be transformed into chitosan nanomaterials. The unique properties and applications of nanotechnology in targeting fish processing technology have received increased importance during the last twenty years. The application of nanotechnology in fishery products is rapidly increasing, and investigating the toxicity and safety of these nanoparticles is essential before their nutritional use. Therefore, this study aimed to determine the acute and chronic toxicity of crab chitosan and its nanoparticles (ChNPs) on albino mice and sprague Dawley rats, respectively. Acute toxicity revealed that crab chitosan and chitosan nanoparticles were completely safe up to 10g/kg of mice body weight which is equivalent to 38.75g/70kg of man body weight, as there was no mortality among used mice. Chronic toxicity testing using 200mg/kg crab chitosan and 100 & 200mg/kg chitosan nanoparticles revealed no changes in all the assayed biochemical parameters when compared with those of control rats. No changes were detected in the lipid profile (T-Ch, TG, HDL-Ch& LDL-Ch) of rats given chitosan in normal and nano form in comparison with normal rats. Levels of plasma protein, albumin, globulin and A/G ratio showed no significant differences among different groups. Normal levels of kidney functions (creatinine & urea) and liver enzymes (ALT & AST) for all studied groups were obtained compared to normal rats. Histopathological examinations of liver sections showed nearly normal appearance in all studied groups. In conclusion, the prepared crab chitosan nanoparticles can be added to the non-toxic (safe) class of materials. It seemed to be an upcoming product that can be used safely as food additives. [ABSTRACT FROM AUTHOR]

Waste crab shells (CS) have the potential to mineralize CO2, yielding precipitated calcium carbonate (PCC) powder feedstock for use in the synthesis of monocalcium phosphate monohydrate (MCPM) in an acidic condition by partial neutralization of phosphoric acid at 90 °C and varying times (30–120 min), followed by evaporation of the water at 100 °C. The PCC and MCPM products were analyzed using X‐ray powder diffraction, Fourier transform infrared spectroscopy, and the scanning electron microscopy/energy dispersive X‐ray method. After 120 min of stirring, the pure MCPM revealed uniform particle sizes from 1 to 3 μm. The presented MCPM synthesis using the PCC powder precursor may assist in developing a large‐scale MCPM industry while recycling a considerable quantity of CS waste. [ABSTRACT FROM AUTHOR]

In order to promote the yield and calorific value of combustible gas products in the pyrolysis, a CaO-based biochar (CSC) derived from waste crab shell was used as a low-cost sorption-enhanced catalyst to enhance oil-fried sludge (OS) pyrolysis. The effects of CSC addition and pyrolysis temperature on OS pyrolysis characteristics were analyzed in detail. The results indicated that adding CSC significantly enhanced OS pyrolysis and produced more combustible gas products with CO2 removal. At 700 °C, adding CSC promoted the combustible gas yields and greatly reduced CO2 by 96.9 %. And the corresponding LHV of pyrolysis gas products increased by 26.8 % and reached up to 33.7 MJ/N m3. Additionally, TG-FTIR analysis revealed that adding CSC reduced the formation temperature of CH4. Importantly, although there was only 35.5 wt% of Ca in CSC, CSC exhibited almost the same sorption-catalysis-enhanced effects compared to pure CaO. These findings suggest that biochar derived from crab shell has the potential to replace CaO for enhancing sludge pyrolysis into value-added fuel products. [ABSTRACT FROM AUTHOR]

Underwater bionic-legged robots encounter significant challenges in attitude, velocity, and positional control due to lift and drag in water current environments, making it difficult to balance operational efficiency with motion stability. This study delves into the hydrodynamic properties of a bionic crab robot's shell, drawing inspiration from the sea crab's motion postures. It further refines the robot's underwater locomotion strategy based on these insights. Initially, the research involved collecting attitude data from crabs during underwater movement through biological observation. Subsequently, hydrodynamic simulations and experimental validations of the bionic shell were conducted, examining the impact of attitude parameters on hydrodynamic performance. The findings reveal that the transverse angle predominantly influences lift and drag. Experiments in a test pool with a crab-like robot, altering transverse angles, demonstrated that increased transverse angles enhance the robot's underwater walking efficiency, stability, and overall performance. [ABSTRACT FROM AUTHOR]

The current investigation aims on valorization of marine fishmeal industry oil as alternate feedstock for biodiesel production using waste crustacean shell derived catalysts such as calcined shrimp shell (SSBD) at 1:12 oil-to-methanol molar ratio, 5 wt% catalyst dosage, 65 °C temperature, and 120 min reaction time and calcined crab shell (CSBD) at 1:9 oil-to-methanol molar ratio, 3 wt% catalyst concentration, 60 °C temperature and 60 min time, and validate their authenticity for application in diesel engine by evaluating engine performance, combustion, and gas emission characteristics. The SSBD and CSBD yield of 88.74 wt% and 87.47 wt% was obtained at 50 L biodiesel production. The fuel properties of SSBD and CSBD blends (B5, B20, and B50) ensured their application in diesel engine. The brake specific fuel consumption and brake thermal efficiency values for all SSBD and CSBD blends didn't exhibit major deviation than diesel at 11.93 kW engine load, and ranged from 0.23 to 0.25 kg/kWh and 31.58–36.17%, respectively. Among all blends, the B50 blend of SSBD and CSBD reduced CO, CO 2 , and HC emissions up to 74.72% and 86.81%, 13.11% and 16.63%, and 35.09% and 58.54%, respectively. Overall, SSBD and CSBD produced using alternate novel feedstock and catalyst could pave way to meet energy demand and sustainable biodiesel production. [Display omitted] • Impact of calcined shrimp shell and crab shell catalyzed MFMI oil biodiesel on diesel engine was investigated. • Physicochemical and fuel properties of B5, B20, and B50 SSBD and CSBD blends were within international standard limits. • BSFC range was 0.23–0.25 kg/kWh, and the BTE range was 31.58–36.17% for all SSBD and CSBD blends. • B50 CSBD blend exhibited peak cylinder pressure of 55.8 bars and maximum heat release rate of 70.80 J/deg. • B50 CSBD showed maximum reduction of CO, CO 2 , and HC emissions up to 86.81%, 16.63%, 58.54%, than all the other blends. [ABSTRACT FROM AUTHOR]

Bone tissue engineering offers a novel therapy for repairing bone defects or fractures. However, it is becoming increasingly challenging because an ideal scaffold should possess a similar porous structure, high biocompatibility, and mechanical properties that match those of natural bone. To fabricate such a scaffold, biodegradable polymers are often preferred due to their degradability and tailored structure. This study involved the isolation of chitosan from crab shells (Scylla serrata) waste to use as a biomaterial in combination with hydroxyapatite (HAP) and collagen I (COL I) to mimic the extracellular matrix (ECM) composition of bone. After being cast and freeze-dried, it resulted in an interconnected porous scaffold with a porosity of 51.44% ± 2.28% and a pore diameter of 109.88 μm ± 49.84 μm. The swelling ratio of the crab scaffold was measured at 358.31% ± 25.23%, 363.04% ± 1.56%, and 370.11% ± 3.7% at 1, 3, and 6 h, respectively. Consequently, the scaffold exhibited a degradation ratio of 8.17% ± 2.59%, 21.62% ± 5.43%, 22.59% ± 14.23%, and 23.12% ± 6.28% over the course of 1 to 4 weeks. It demonstrated excellent biocompatibility with MG-63 osteosarcoma cells. Although the compression strength was lower than 2-12 MPa, the crab scaffold can still be applied effectively for non-load-bearing bone defects. Crab shell waste emerges as a promising source of chitosan for tissue engineering applications. [ABSTRACT FROM AUTHOR]

Aflatoxin B1 (AFB1) is extremely hepatotoxic, a causative agent of liver cancer, and can cause symptoms of acute or chronic liver damage. Chito-oligosaccharides (COS), obtained from the degradation of chitosan derived from shrimp and crab shells, is a natural antioxidant substance and its antitumor properties have been widely studied, but less research has been done on the prevention of AFB1-induced acute liver injury. In this study, rats were acutely exposed to 1 mg/kg BW AFB1 and simultaneously gavaged with different doses of COS for 8 days. The results showed that COS attenuated the hepatic histopathological changes and reduced serum biochemical indices (ALT, AST, ALP, and TBIL) in rats. It significantly inhibited MDA content and promoted SOD and GSH-Px activity production. Moreover, it also improved hepatocyte apoptosis. Furthermore, AFB1-vs-HCOS differential genes were enriched with 622 GO entries, and 380 were Biological Processes, 170 were Molecular Functions, 72 were Cellular Components. Differentially expressed genes (DEGs) analyzed by KEGG enrichment were more enriched in pathways, such as metabolism, PPAR signaling pathway, and peroxisome. Q-PCR technique verified that Lama5, Egr1, Cyp2b1, and Gadd45g in DEGs were associated with oxidative stress damage and apoptosis. In conclusion, COS intervention reduces the effect of AFB1 on hepatic genes and thus reduces the changes in hepatic gene function. Key Points: AFB1 induced oxidative stress injury and apoptosis of liver. AFB1 activated Lama5, Egr1, Cyp2b1, and Gadd45g genes and signaling pathways. COS attenuated AFB1-induced hepatotoxicity. COS regulated Lama5, Egr1, Cyp2b1, and Gadd45g genes and signaling pathways. [ABSTRACT FROM AUTHOR]

The amount of processed by-products such as crab shells is increasing, but industrial utilization is insufficient. In our previous study, crab shell extract (CSE) acted as a coagulant for tofu manufacturing. This study aimed to reduce freeze-dried (FD) tofu breakdown by improving its physical properties through adding sodium alginate (SA). FD state in tofu helps increase storage and availability, but FD tofu frequently fractures during processing, which is a concern for manufacturers. Tofu samples were prepared with either crab shell extract (CSE) or MgCl2, and SA, and freeze-dried. In the yields of FD tofu samples, there were no significant differences (p < 0.05). The brokenness of FD tofu samples was lower in CSE than in MgCl2 and was significantly reduced by SA in both tofu samples, which was affected by hardness. The water-holding capacity decreased after freeze-drying, and CSE reduced this decrease, regardless of SA addition. The microstructures differed depending on the coagulant and were dense upon SA addition. The FD tofu was packed into a multilayer film and stored at 25 °C or 45 °C for 6 months to investigate storage stability. During the storage, brokenness was unchanged in all tofu samples, indicating that they maintained their original structure. There were no significant differences in the volatile base nitrogen and thiobarbituric acid values according to the coagulant type and SA addition (p < 0.05). In conclusion, SA reduced FD tofu breakdown by improving the network structure, which may help increase FD tofu quality and decrease economic loss. [ABSTRACT FROM AUTHOR]

The inorganic component of bone matrix, hydroxyapatite (HAp) (with formula Ca10(PO4)6(OH)2), can be obtained from inexpensive waste resources that serve as excellent calcium precursors. In the present study, HAp nano-powder was synthesized from eggshells (ES) and crab shells (CS) by wet chemical precipitation method. Also, a hybrid sample was considered which is a mixture of HAp nano-powder synthesized from eggshells (25%) and crab shells (75%) (EC). The presence of phosphate, carbonate, and hydroxyl groups in the synthesized powder was confirmed through FTIR analysis. The phase composition was determined using XRD, and elemental analysis revealed a Ca/P ratio ranging from 1.5 to 1.8, confirming the HAp nature of the nano-powder, which ranged in size from 73 to 375 nm. Importantly, preliminary in vitro tests were conducted using mouse preosteoblast cell line MC3T3-E1 to evaluate the cytotoxic effects of the synthesized HAp. The results indicated excellent biocompatibility. Moreover, sample EC exhibited a significantly higher proliferation on days 3, 6, 9, and 12. EC demonstrated promising antimicrobial properties by exhibiting a significantly higher inhibitory effect against the bacteria Streptococcus mutans and Escherichia coli, and the fungi Candida albicans and Aspergillus niger. Additionally, EC displayed notable antioxidant activity, with IC50 values of 271.543 µg/ml and 407.764 µg/ml in DPPH and H2O2 assays, respectively. Furthermore, it showed strong anti-inflammatory properties, with a dose-dependent inhibition against protein denaturation. Given these findings, the synthesized HAp holds promise as a potential bone filler and could be beneficial for bone remodeling applications. [ABSTRACT FROM AUTHOR]

A novel nanoporous adsorbent was obtained through the thermal treatment and chemical wash of the wasted crab shells (BC1) and characterized by various techniques. The structure of BC1 at the end of the treatments comprised a mixture of calcite and amorphous CaCO3, as evidenced by X-ray diffraction and Fourier transform infrared absorption. The BET surface area, BET pore volume, and pore diameter were 250.33 m2 g−1, 0.4 cm3 g−1, and <70 nm, respectively. The point of zero charge of BC1 was determined to be around pH 9. The prepared adsorbent was tested for its adsorption efficacy towards the neonicotinoid pesticide acetamiprid. The influence of pH (2–10), temperature (20–45 °C), adsorbent dose (0.2–1.2 g L−1), contact time (5–60 min), and initial pesticide concentration (10–60 mg L−1) on the adsorption process of acetamiprid on BC1 was studied. The adsorption capacity of BC1 was 17.8 mg g−1 under optimum conditions (i.e., 20 mg L−1 initial acetamiprid concentration, pH 8, 1 g L−1 adsorbent dose, 25 °C, and 15 min contact time). The equilibrium data obtained from the adsorption experiment fitted well with the Langmuir isotherm model. We developed an effective nanoporous adsorbent for the recycling of crab shells which can be applied on site with minimal laboratory infrastructure according to local needs. [ABSTRACT FROM AUTHOR]

Proteins in tears, including human lactoferrin (HLF), can be deposited and denatured on contact lenses, increasing the risk of microbial cell attachment to the lens and ocular complications. The surfactants currently used in commercial contact lens care solutions have low clearance ability for tear proteins. Chitosan oligosaccharide (COS) binds to a variety of proteins and has potential for use in protein removal, especially in contact lens care solutions. Here, we analyzed the interaction mechanism of COSs hydrolyzed from chitosan from different resources with HLF. The molecular weights (MWs) and concentrations of COSs were key factors for the formation of COS–HLF complexes. Lower MWs of COSs could form more stable COS–HLF complexes. COS from Aspergillus ochraceus had a superior effect on HLF compared with COS from shrimp and crab shell with the same MWs. In conclusion, COSs could bind to and cause a conformational change in HLF. Therefore, COSs, especially those with low MWs, have potential as deproteinizing agents in contact lens care solution. [ABSTRACT FROM AUTHOR]

We describe the use of abraded bivalve shells by the shellback crabs Hypoconcha arcuata Stimpson, 1858 and H. parasitica (Linnaeus, 1763) in southeastern Brazil. Shells from four species of bivalves were associated with the crabs: Eucallista purpurata (Lamarck, 1818), Chionopsis crenata (Gmelin, 1791), and Tivela zonaria (Lamarck, 1818) (Veneridae), and, most frequently (50%), Dallocardia delicatula (E.A. Smith, 1915) (Cardiidae). This was the first documented record of shellback crabs using valves of veneriid bivalves, as well as the first report of a crab-shell association for Hypoconcha in the South Atlantic Ocean. The relationship between the increase in size of shellback crabs and the size of the chosen shell was discussed. [ABSTRACT FROM AUTHOR]

Betta splendens, Siamese fighting fish exhibit behavior, coloration, and morphology that make them popular aquarium fish in aquaculture. Coloration for this fish requires high-quality feeds rich in carotenoids. Crab shells, mostly dumped as agro-waste by the seafood industry contain carotenoids and protein that can be an alternative for carotenoids in fish feed. The objectives of this study were to analyze the proximate composition and carotenoid content in feed and determine the effect of crab shells as feedstuff on the growth performance and coloration of Betta splendens. A 40-day feeding trial using 45 tails of B. splendens with an average body weight, of 0.25 g was conducted by using five feed treatments namely TC (0% crab shell), T1 (25% crab shell), T2 (50% crab shell), T3 (75% crab shell) and T4 (100% crab shell) respectively. Sampling was done weekly. Analysis done were proximate composition and extraction of carotenoid while growth performance parameters such as body weight gain (BWG), specific growth rate (SGR), feed intake (FI), and feed conversion ratio (FCR) were also taken. Skin coloration and water quality data were collected every 10 days. All data were analyzed using One-Way ANOVA via SPSS. Results showed protein content for T1 (22.40±0.29) was slightly higher compared to all treatments. Carotenoid content in crab shells was lower compared to krill. Body weight from T1 (25% crab shell) showed a significant increase among all treatments. All treatments show no changes in coloration. In conclusion, T1 (25% crab shell waste) is the best treatment as it has a high protein content that improves body weight gain without any significant effect on coloration in all treatments. [ABSTRACT FROM AUTHOR]

Verminosis in small ruminants can render rural activity impractical, which is still controlled through the administration of anthelmintics. The present study evaluated four agro-industrial residues as fertilizer in the control of GIN of small ruminants in the freeliving stage. Crab shell, manipueira, biochar, and organomineral residues were used in pots (5.0 kg of soil) and cultivated with Massai grass (Megathyrsus maximum cv. Massai). Further, the pots were contaminated with feces from sheep carrying a natural multispecific infection by GIN. Next, the residues were applied individually to the soil, with 50 mL/pot for liquid and 50 g/pot for solid residues. Treatment with manipueira showed the lowest number of L3.kg MS-1 recovered from the grass (202.44), when compared with treatments using organomineral (823.89) and biochar (689.34). However, there was no statistically significant difference (P < 0.05) between the four treatments as compared to the control group. These agro-industrial residues can be used as organic fertilizers; however, these will not help in the control of GIN in sheep. [ABSTRACT FROM AUTHOR]

The present work deals with the development of novel biopolymer-based composite hydrogels (HGs) based on chitosan and protein isolate derived from marine byproducts, and their functional applications. Chitosan (Cs) from blue crab shells and bluefin tuna protein isolate (BTPI) were selected to prepare composite hydrogels. The data from the characterization demonstrated that by increasing the BTPI content to 20% (w/w, Cs), hydrogels became more porous, elastic, and mechanically stable. Furthermore, all HGs present good antioxidant activity in a BTPI concentration-dependent manner. Based on the overall structural, swelling, and mechanical properties, HG-20 was selected for in-vitro release study of phycocyanin. Release patterns show that HG-20 is able to release phycocyanin (Ph) under acidic and neutral microenvironments. The local application of HG-20 loaded or not by Ph for wound repair in rats' models was further studied. All tested HG exhibited an interesting wound healing-promoting ability. Importantly, Ph-loaded HG-20 has been found to accelerate wound closure, compared to unloaded HG-20. [ABSTRACT FROM AUTHOR]

Purpose Aggressive use of crop fertilizer during food production caused an overburden in the environment. Gradual release of crop nutrients from the fertilizer could decrease the massive utilization of fertilizer. The advantages are two folds, cheaper cost, and environmentally friendly crop production. Method Slow-release fertilizer was prepared by encapsulating hydroxyapatite (HA) with a single fertilizer. The HA which derived from crab shell biowaste was synthesized by the wet precipitation method. The nitrogen release test was carried out every 5 minutes for 1 hour using the percolation method, then the percolates were tested for the total nitrogen content. Fertilizer was applied to see its effect on the vegetative and generative growth of tomato plants. Five treatments were applied: without fertilizer as control, ammonium sulfate (AS) fertilizer, hybrid AS-HA fertilizer, urea (U) fertilizer, and U-HA fertilizer. Results AS-HA released nitrogen at 4.45% or three times slower than AS which released 13.51%. U-HA released nitrogen as much as 3.96% or 4.5 times slower than urea which released nitrogen as much as 18.66% in one hour. AS-HA fertilizer provided the best results for overall parameters, with an average height of 102.1 cm for plant height, 7 mm for stem diameter, 82 strands for number of leaves, 4 produced fruits, and 63.5 grams for the fruit weight per plant. Conclusion Slow-release fertilizer with a mixture of hydroxyapatite was able to release nitrogen gradually. Korsmeyer-Peppas model was the best-fitted model for nitrogen release. [ABSTRACT FROM AUTHOR]