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With the growing sophistication of cloning technology, rescuing cell resources is of great significance for the protection of endangered animals. The Yangtze sturgeon (Acipenser dabryanus), one of the three Acipenseriformes species in the Yangtze River, is critically endangered. Natural reproduction of the Yangtze sturgeon has not been detected since 2000. Less than 20 wild individuals are kept in husbandry, and all are too old to breed. Therefore, it is urgent to rescue the genetic resources of every wild Yangtze sturgeon. Here, we isolated and preserved viable cells from critically endangered postmortem Yangtze sturgeon for the first time. Attempts to rescue and preserve cell resources were carried out from 8 tissues, brain, kidney, gonad, fin, liver, skin, spleen, and muscle of an over 35-year-old female wild Yangtze sturgeon between 11 and 14 hours after death at 19.8°C in an outdoor concrete pond, and only muscle tissue cells could be successfully subcultured and preserved. Furthermore, the cultured cells showed high post-thaw cell viability and normal growth with a population doubling time of 52.98 h. Moreover, they were fibronectin- and desmin-positive, characterizing them as fibroblastic confirmed muscle cells with fibroblastic properties and myogenic origin. Tests for microbial contamination of the cell lines were negative. Chromosome analysis demonstrated that muscle cells possess a modal polyploid chromosome number of 264. The mitochondrial sequence data of COI genes and 12S rRNA confirmed that the developed cell line originated from A. dabryanus. Furthermore, transfection results indicate that muscle cells could be used for gene manipulation and functional studies. These results suggest that viable muscle cells could also be successfully isolated and cryopreserved from the wild Yangtze sturgeon in a short time after death. This report is not only of great significance for the germplasm rescue of critically endangered Yangtze sturgeon but also provides some scientific reference for the germplasm preservation of other endangered fish.

Melting and solidification in metal-based additive manufacturing (AM) ultimately determine the crystallographic texture, cellular/columnar dendritic growth, solute segregation, and resultant materials properties. The microstructure of AM-built alloys is closely related to various physics during the printing process. In the present study, a multi-physics model was developed to simulate the evolution of grain and dendritic-scale microstructure during laser AM of a Ni-based alloy. Computational fluid dynamics was used to simulate the melt pool dynamics and temperature distribution for the laser powder bed fusion process. Using Ni-Nb as an analogue to Inconel 625, a phase field model was applied to predict the microstructural features within a two-dimensional solidified melt pool. The predicted results exhibit fair agreement with experimental characteristics in the literature, including melt pool profile, dendrite size, dendrite morphology, and crystallographic texture. The multi-physics model paves the way for computationally predicting the chemistry-process-structure relationship in AM-built alloys, which helps to understand the fundamental physics of AM solidification. National Research Foundation (NRF) The authors acknowledge the support by the National Research Foundation, Prime Minister’s Office, Singapore, under its Medium Sized centre funding scheme.

Crystallization of polyamide 12 (PA12) is an essential process requiring thorough investigation for evaluating the mechanical properties after the polymer parts are manufactured. The change in crystallization temperature results in different crystallization behaviors for PA12. Hence, the crystal morphology of PA12 achieved provides important information about crystallization behavior, especially for those produced through additive manufacturing due to its heterogenous cooling rate in a single print bed. Considering the need of investigating PA12 crystallization using phase-field modeling, this paper aims to simulate the spherulite morphology of PA12 undergoing isothermal crystallization. This model is compared with the spherulite morphologies obtained from the optical microscopy test. The model shows that PA12 spherulites have thicker dendrites when the isothermal temperature is higher. The present phase-field model can determine the spherulite morphologies of bulk printed PA12 based on the crystallization condition and be used to evaluate the properties of the printed part. Nanyang Technological University This research work is conducted in collaboration with HP Inc. and supported by Nanyang Technological University and the Singapore Government through the Industry Alignment Fund–Industry Collaboration Projects Grant (I1801E0028).

Soil-water characteristic curve (SWCC) correlates the water content of a soil to its soil suction, which is a very important property of unsaturated soils. Osmotic tensiometers (OTs) have shown their capability in high soil suction measurement. This study tried to use OT combined with a pressure plate and WP4C dewpoint potentiometer to determine the SWCC of a residual soil. Three OTs with different measuring ranges (900 kPa, 1200 kPa, 2300 kPa) were prepared for soil suction measurement. The temperature effect on the pressure variations of OTs was illustrated based on Flory-Huggins polymer theories and an appropriate calibration equation was proposed to eliminate the temperature effect on the accuracy of soil suction measurement using OT. The OT showed a fast response in soil suction measurement and the equilibrium can be established in 10–15 min during SWCC measurement. Comparison of the SWCC data obtained from the pressure plate, OT, and WP4C dewpoint potentiometer proves that the OT had good performance in the determination of SWCC, especially for the transition zone (i.e., 10–1500 kPa suction range), by providing more data points to define the SWCC in a shorter period. The results show that the usage of OT will shorten the time required for the determination of SWCC and could be considered as a new and reliable technique in SWCC measurement. Submitted/Accepted version

An adaptive phase-field modeling approach is developed for the dynamic brittle fracture of composite materials subjected to impact loading. This approach is capable of capturing the dynamic fracture patterns in composite materials including matrix cracking, delamination between adjacent plies, and interaction between the two failure modes via the exploitation of interface and crack phase fields. The driving force for the crack evolution is derived by introducing the contributions of the longitudinal and transverse damage considering the tension–compression asymmetry. Moreover, an anisotropic crack surface density function is introduced by considering the material anisotropy induced by fibers. The computational efficiency of the dynamic fracture modeling is improved via the adaptive mesh refinement strategy within the framework of the isogeometric-meshfree approach. The Newmark implicit integration scheme is used for the temporal discretization of the phase-field governing equations. Finally, simulations of both mode-I and mixed-mode fracture, such as the dynamic branching and the three-point bending tests, are implemented for homogeneous materials and composites, which demonstrates the reliability of the developed approach. Nanyang Technological University The authors would like to acknowledge the financial support from Nanyang Technological University.

The fourth-order phase-field modeling of ductile fracture in elastic–plastic materials is performed via an adaptive isogeometric-meshfree approach. In the developed phase-field model, the total energy functional consists of the elastic contribution and the dissipated contribution because of fracture and plasticity. The coupling of the plasticity to fracture is implemented by a degradation function that is applied to the elastic energy. The present fourth-order phase-field model is capable of relaxing the mesh size requirements while accurately regularizing sharp cracks. To further enhance the computational efficiency, the isogeometric-meshfree approach is adopted for the numerical implementation of the phase-field model within a staggered computational framework. The developed approach can flexibly implement the C1-continuity of a crack phase field that is required by the fourth-order model. Moreover, an adaptive mesh refinement strategy is developed, which includes the gradient-based refinement indicators and the field transfer operators. Numerical simulations of a series of representative cases show that the developed fourth-order model can accurately and efficiently capture complex ductile fracture patterns including plastic localization, crack initiation, propagation, and merging, which demonstrates the reliability of the adaptive fourth-order phase-field modeling of ductile fracture. National Research Foundation (NRF) This work was supported by the National Research Foundation, Prime Minister’s Office, Singapore under its Medium-Sized Centre funding scheme through the Marine and Offshore Program.

SummaryIn this study, we tried to maintain the vitality of Chinese sturgeon (Acipenser sinensis) ova before fertilization with several treatments in vitro. The ovulated eggs were allocated to groups with different incubation medium (coelomic fluid and artificial media), temperature (4°C and 16°C) and storage duration (2 h and 6 h). The maximum fertilization and hatching rate were observed for the control group in which the ova were fertilized immediately after spawning, with the values of 82.45% and 84.73%, respectively. Compared with the control group, the fertilization and hatching rate of all the treatment groups stored at 4°C or in coelomic fluid decreased significantly (P < 0.05). The fertilization rate of the treatment group stored in artificial medium at 16°C did not change obviously in the first 2 h (P > 0.05), but declined dramatically (P < 0.05) after 6 h. In comparison with the control group, no significant (P > 0.05) reduction was shown in hatching rate of the treatment group stored in artificial medium at 16°C for 6 h. The results showed that the ova of Chinese sturgeon can be stored for at least 6 h at 16°C in artificial medium without weakening; this provides a practical application method for the routine hatchery practice of Chinese sturgeon, as well as certain relevant research.

The hypothalamus and pituitary serve as important neuroendocrine center, which is able to secrete a variety of neuropeptides and hormones to participate in the regulation of reproduction, growth, stress and feeding in fish. Chinese sturgeon is a basal vertebrate lineage fish with a special evolutionary status, but the information on its neuroendocrine system is relatively scarce. Using the transcriptome data on the hypothalamus-pituitary axis of Chinese sturgeon as reference, we found out 46 hypothalamus neuropeptide genes, which were involved in regulation of reproduction, growth, stress and feeding. The results of sequence alignment showed that the neuroendocrine system of Chinese sturgeon evolves slowly, which confirms that Chinese sturgeon is a species with a slow phenotypic evolution rate. In addition, we also isolated six pituitary hormones genes from Chinese sturgeon, including reproductive hormones: follicle-stimulating homone (FSH) and luteinizing hormone (LH), growth-related hormones: growth hormone (GH)/prolactin (PRL)/somatolactin (SL), and stress-related hormone gene: proopiomelanocortin (POMC). Similar to teleost, immunostaining localization analysis in Chinese sturgeon pituitary showed that LH and FSH were located in the pituitary proximal pars distalis, SL was located in the pituitary rostral pars distalis, and POMC was located in the pituitary pars intermedia and pituitary rostral pars distalis. This study will give a contribution to enrich our information on the neuroendocrine system in Chinese sturgeon.

Yangtze sturgeon (Acipenser dabryanus) is an endangered endemic freshwater fish of China. Cell-line is a potential means used for long-term preservation of germplasm resources and an ideal in vitro model in place of living organisms for biological studies. Here, culture condition and characterization of fin-derived cell in Yangtze sturgeon were carried out. Tissue explant techniques have been efficiently used in the Yangtze sturgeon caudal fin (YSCF) culture. The YSCF cell line showed a fibroblast-like morphology and stable growth in minimum essential medium eagle's (MEME) supplemented with 10-20% fetal bovine serum at 25°C. Cells were cryopreserved with preservative DMSO in liquid nitrogen and grew normally after recovery. No bacterial, fungal, or mycoplasma contamination was detected in the YSCF cells. Karyotype analysis of the YSCF cells showed that the chromosome numbers of the YSCF ranged from 242 to 273, and the modal chromosome number was identified as 264 at passage 9. The YSCF cells were confirmed from A. dabryanus by assay of 16S rRNA and COI. Furthermore, GFP reporter gene was successfully transferred into YSCF cells and expressed. The established YSCF cell lines will contribute to the preservation of germplasm resources and provide a useful vitro tool for further biological studies in sturgeon species.

Chinese sturgeon (Acipenser sinensis) has been listed as a critically endangered species on the IUCN Red List and is an endemic fish of China. Five sets of duplex polymerase chain reactions (PCR) assays were developed with 10 tetranucleotide microsatellites for Chinese sturgeon. The size of CS57, ZHX43, ZHX69, AS105, ZHX51, AS074, ZHX2, AS078, AS026 and AS073 products in 184 Chinese sturgeon individuals ranged from 257–305, 191–241, 251–285, 172–244, 236–260, 169–209, 194–234, 92–176, 165–257 and 120–164, respectively. The observed allele number of the 10 microsatellites ranged from 7 to 16, and the total number of alleles was 106. The number of alleles per individual in CS57, ZHX43, AS105, AS074, AS078 and AS026 was 1–4. The number of alleles per individual in ZHX69, ZHX51, ZHX2 and AS073 was 2–4. The mean number of alleles per locus per individual ranged from 2.01–3.76. The expected heterozygosity (HE), observed heterozygosity (HO), polymorphic information content (PIC) and Shannon-Weiner diversity index (H′) ranged from 0.582 to 0.899, from 0.676 to 1, from 0.518 to 0.886 and from 1.034 to 2.34, respectively. Despite many advantages, the use of microsatellites as genetic analysis tools can be limited by the cost of the associated experiment. To solve this problem, this set of five duplex PCRs will provide tools that are more helpful, less expensive and less time consuming than others used for genetic analyses in Chinese sturgeon.

With the growing sophistication of cloning technology, rescuing cell resources is of great significance for the protection of endangered animals. The Yangtze sturgeon (Acipenser dabryanus), one of the three Acipenseriformes species in the Yangtze River, is critically endangered. Natural reproduction of the Yangtze sturgeon has not been detected since 2000. Less than 20 wild individuals are kept in husbandry and all are too old to breed. Therefore, it is urgently to rescue the genetic resources of every wild Yangtze sturgeon. Here, we isolated and preserved viable cells from the post-mortem critically endangered Yangtze Sturgeon for the first time. Attempt of rescuing and preserving cell resources were carried out from 8 tissues, brain, kidney, heart, fin, liver, skin, spleen and muscle of over-35-years-old female wild Yangtze sturgeon between 11 and 14 hours after death at 19.8℃ in outdoor concrete pond, and only muscle tissue cells could be successfully sub-cultured and preserved. Furthermore, the cultured cells were assessed by population doubling time, immunofluorescence analysis, microorganism detection, karyotyping and origin identification, and no abnormality was observed in the morphology, structure, growth and ploidy. These results suggest that viable cells could also be successfully isolated and cryopreserved from the wild Yangtze sturgeon in a short time after death, and muscle tissues had more potential to separate living cells than other tissues. This report is not only of great significance to the germplasm rescue of critically endangered Yangtze sturgeon, but also provides some scientific reference for the germplasm preservation of other endangered fish.

With the capability to build components with freeform geometries, laser powder bed fusion (L-PBF) is considered as one of the most promising techniques for industrial applications. Compared to conventional manufacturing technologies, an additional advantage of L-PBF process is the capability to fabricate parts with multiple materials, such as in-situ alloying and functionally graded alloys. In this regard, here we present a computational model to simulate the L-PBF of multiple materials. Based on volume of fluid (VOF) methods and computational fluid dynamics (CFD), the multi-physics multi-material model was successfully implemented with various physics of L-PBF process, including surface tension, Marangoni shear force, recoil pressure, compositional diffusion, etc. In addition, we demonstrated the numerical algorithm of ray tracing heat source for multiple materials. With reasonable assumptions, conduction mode or keyhole mode laser melting of miscible materials can be simulated via the proposed computational framework. Furthermore, such multi-physics model is capable of simulating L-PBF of an arbitrary number of materials. The computational model can help achieve insightful understanding of the L-PBF of multiple materials. National Research Foundation (NRF) The authors acknowledge the support by the National Research Foundation, Prime Minister’s Office, Singapore under its Medium Sized center funding scheme.

Compared with conventional water-filled tensiometers, polymer-filled osmotic tensiometers (OTs) can measure a higher matric suction by increasing the osmotic pressure of the water inside the tensiometer. The measuring range of OT is equal to the osmotic pressure of water inside the OT. All previous research used commercial polymers in developing OTs and the mechanism of long-term pressure decay of OTs was not found. In this study, polymers including polyacrylamide (PAM) and sodium polyacrylate (NaPA) with different degrees of crosslinking were synthesised by UV polymerisation to develop new OTs. Long-term pressure variations of OTs indicated that the pressure decay was more likely due to the stress relaxation of polymer materials instead of polymer leakage. PAM-filled OTs have a faster stress relaxation behaviour than NaPA-filled OTs so that they can keep constant pressure (i.e., constant measuring range) for a long time and there is no need for pressure correction based on the pressure decay rate. However, the measuring range of PAM-filled OTs is lower than that of NaPA-filled OTs. The result of matric suction measurements demonstrated that the proposed OTs can be used to measure matric suction both in low and high ranges with fast response and high accuracy. Nanyang Technological University National Parks Board Submitted/Accepted version The authors would like to acknowledge the financial support from Nanyang Environment and Water Research Institute (NEWRI), Interdisciplinary Graduate School, Nanyang Technological University, Singapore, as well as the National Parks Board, Singapore.

The sox family is assumed to be responsible for a number of developmental systems. Genome sequencing technology makes it possible to scan sox genes and conduct characteristic analyses of different species. In fish, full characterisation of sox genes at the genome-wide level has been reported for pufferfish Takifugu rubripes, medaka Oryzias latipes, tilapia Oreochromis niloticus and channel catfish Ictalurus punctatus. However, no systematic investigation of the sox family in sturgeons (Acipenseridae) has been reported to date. This study conducted genome-wide identification of the sox genes in the Chinese sturgeon Acipenser sinensis and profiled their tissue distribution between male and female individuals. In total, 19 sox genes were identified, including soxb1, b2, c, d, e, f and h, in the Chinese sturgeon. Genomic structure analysis indicated relatively conserved exon-intron structures in each sox group and phylogenetic analysis supported the previous classification of the sox family. Most of the sox genes showed a tissue-specific expression pattern, indicating the possible involvement of Chinese sturgeon sox genes at different developmental processes such as cardiac and gonadal development. This study provides a comprehensive resource of Chinese sturgeon sox genes and enables a better understanding of the evolution and function of the sox family.

Photodetectors, which are capable of detecting light with varied wavelength, have nowadays been widely applied onto emerging fields such as security, entertainment, healthcare, environment, and so on. As the one with a two-dimensional layered structure, molybdenum disulfide (MoS2) possesses striking optical and electrical properties that can be used in photodetecting, yet the challenges remain in terms of material processing, device fabrication simplicity, and enhancement of overall photodetection performance. In this work, a photodetectable paper based on a mixture of double-phased MoS2 (1T and 2H) and MoO3 was successfully fabricated through a straightforward route, that is, chemical exfoliation and deposition of MoS2 powder on a flexible cellulose ester membrane, followed by inkjet-printed PEDOT:PSS as electrodes. The obtained device shows varied sensitivity to the light with different wavelengths. Compared with that under green and red lights, the prepared photodetector has the highest internal quantum efficiency (0.063%) and responsivity (0.134 mA W-1), while having longest response/recovery time (17.5/15.3 s) when illuminated with purple light (405 nm). The achieved responsivity is much higher than other reported liquid exfoliation- and solution-derived MoS2 photodetectors. This is ascribed to (1) the enhanced photoelectron generation caused by both MoS2 and MoO3 and (2) the good electric conductivity and efficient charge transport caused by the metallic 1T MoS2. This work demonstrates the feasibility of fabricating the MoS2-based photodetector with excellent performance through a simple exfoliation/filtration and inject printing route, and the detailed study on the response to light with different wavelengths unveils the interaction between the device and the incident light, further broadening the potential applications of such design.

Inspired by shape-morphing organisms in nature, researchers have developed various hydrogels with stimuli-responsive swelling, shrinking, bending, folding, origami, rolling, twisting, or locomotion. These smart hydrogels are usually created by patterning or 4D printing. The shape morphing of hydrogels allows the fabrication of helixing, twisting, and rolling microstructures, all of which are hard to reproduce directly by ordinary techniques. More importantly, under external stimuli (e.g., solvent, humidity, temperature, light, pH, and electric/magnetic fields), many hydrogels exhibit recoverable shape morphing and thus find promising applications in grippers, sensors, valves, soft robotics, etc. Since shape morphing determines the functions of hydrogels in a great number of cases, herein, recent advances of stimuli-responsive hydrogels are summarized, with their types, shape-morphing mechanisms, fabrication methods, shape-morphing modes, and extensive applications covered. The conclusion and perspectives are also presented to guide the design and fabrication of functional hydrogels. National Research Foundation (NRF) This study was supported by the National Research Foundation, Prime Minister's Office, Singapore under its Medium-Sized Centre funding scheme through the Marine and Offshore Program. This study was also supported under the RIE2020 Industry Alignment Fund-Industry Collaboration Projects (IAF-ICP) Funding Initiative, as well as cash and in-kind contribution from the industry partner, HP Inc., through the HP-NTU Digital Manufacturing Corporate Lab.

Airflow sensor is a crucial component for monitoring environmental airflow conditions in many engineering fields, especially in the field of aerospace engineering. However, conventional airflow sensors have been suffering from issues such as complexity and bulk in structures, high cost in fabrication and maintenance, and low stability and durability. In this work, we developed a facile direct-writing method for fabricating a low-cost piezoresistive element aiming at high-performance airflow sensing, in which a commercial pen was utilized to drop solutions of single-walled carbon nanotubes onto tissue paper to form a piezoresistive sensing element. The encapsulated piezoresistive element was tested for electromechanical properties under two loading modes: one loading mode is the so-called pressure mode in which the piezoresistive element is pressed by a normal pressure, and another mode is the so-called bending mode in which the piezoresistive element is bended as a cantilever beam. Unlike many other developed airflow sensors among which the sensing elements are normally employed as cantilever beams for facing winds, we designed a fin structure to be incorporated with the piezoresistive element for airflow sensing, the main function of the fin is to face winds instead of the piezoresistive element, and subsequently transfer and enlarge the airflow pressure to the piezoresistive element for the normal pressure loading mode. With this design, the piezoresistive element can also be protected by avoiding experiencing large strains and direct contact with external airflows so that the stability and durability of the sensor can be maintained. Moreover, we experimentally found that the performance parameters of the airflow sensor could be effectively tuned by varying the size of the fin structure. When the fin sizes of the airflow sensors were 20 mm, 30 mm, and 40 mm, the detection limits and sensitivities of the fabricated airflow sensors were measured as 8.2 m/s, 6.2 m/s, 3.2 m/s, 0.0121 (m/s)−2, 0.01657 (m/s)−2, and 0.02264 (m/s)−2, respectively. Therefore, the design of the fin structure could pave an easy way for adjusting the sensor performance without changing the sensor itself toward different application scenarios.

The complete mitochondrial genome sequence of the hybrid of Huso dauricus (♀) × Acipenser schrenckii (♂) is described in this study. The 16,693bp long circular molecule consisted of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region, showed a typical vertebrate pattern. All genes were encoded on the heavy strain except for ND6 and eight tRNA genes. Base composition of the heavy strain was A(30.40%), T(24.19%), C(29.26%), G(16.16%), and with A + T bias of 54.59%. Comparing with the complete mitochondrial genome of its parents, the hybrid sturgeon of Huso dauricus (♀) × Acipenser schrenckii (♂) was consistent with a maternal inheritance. The complete mitogenome of the hybrid sturgeon of Huso dauricus (♀) × Acipenser schrenckii (♂) provides an important dataset for the exploration of mitochondrial inheritance mechanism.

In this study, we tried to maintain the vitality of Chinese sturgeon (Acipenser sinensis) ova before fertilization with several treatments in vitro. The ovulated eggs were allocated to groups with different incubation medium (coelomic fluid and artificial media), temperature (4°C and 16°C) and storage duration (2 h and 6 h). The maximum fertilization and hatching rate were observed for the control group in which the ova were fertilized immediately after spawning, with the values of 82.45% and 84.73%, respectively. Compared with the control group, the fertilization and hatching rate of all the treatment groups stored at 4°C or in coelomic fluid decreased significantly (P0.05). The fertilization rate of the treatment group stored in artificial medium at 16°C did not change obviously in the first 2 h (P0.05), but declined dramatically (P0.05) after 6 h. In comparison with the control group, no significant (P0.05) reduction was shown in hatching rate of the treatment group stored in artificial medium at 16°C for 6 h. The results showed that the ova of Chinese sturgeon can be stored for at least 6 h at 16°C in artificial medium without weakening; this provides a practical application method for the routine hatchery practice of Chinese sturgeon, as well as certain relevant research.

Reconstructing of cell architecture plays a vital role in tissue engineering. Recent developments of self-assembling of cells into three-dimensional (3D) matrix pattern using surface acoustic waves have paved a way for a better tissue engineering platform thanks to its unique properties such as nature of noninvasive and noncontact, high biocompatibility, low-power consumption, automation capability, and fast actuation. This article discloses a method to manipulate the orientation and curvature of 3D matrix pattern by redesigning the top wall of microfluidic chamber and the technique to create a 3D longitudinal pattern along preinserted polydimethylsiloxane (PDMS) rods. Experimental results showed a good agreement with model predictions. This research can actively contribute to the development of better organs-on-chips platforms with capability of controlling cell architecture and density. Meanwhile, the 3D longitudinal pattern is suitable for self-assembling of microvasculatures. Ministry of Education (MOE) Nanyang Technological University The authors gratefully acknowledge the support of (i) Nanyang Technological University and the Ministry of Education of Singapore through a PhD Scholarship; and (ii) the Academic Research Fund (AcRF) Tier 1 Grants (RG 96/18).

Warpage of printed parts, especially for multi-jet fusion (MJF) process, is believed to have strong correlation with crystallization shrinkage. Hence, this article investigates the shrinkage phenomenon of polyamide-12 (PA12) during crystallization process. Various cooling rates show that PA12 exhibits different crystallization behaviour, which affect the crystallinity, crystal phase and crystal shrinkage when performed in MJF. The investigation shows that crystallization shrinkage of PA12 coincides with the exothermic reaction of crystallization process. With cooling rate as slow as 0.2 °C/min, PA12 sample shrinks 1.64% during the crystallization process with crystallinity calculated at 24.9%. X-ray diffraction (XRD) suggests shrinkage are closely related to lamellar folding and growth of γ crystal phase within PA12 samples during crystallization. Spherulites are found to be smaller in diameter with faster cooling rate. These investigations provide detailed understanding of the crystallization behaviour of PA12 for MJF process. Submitted/Accepted version This research work is supported under the RIE2020 Industry Alignment Fund – Industry Collaboration Projects (IAF-ICP) Funding Initiative (I1801E0028), as well as cash and in-kind contribution from the industry partner, HP Inc.

In this study, the effects of different feeding frequencies on the growth and the expression of genes in the GH/IGF axis were assessed in juvenile Chinese sturgeon. The newly hatched Chinese sturgeons were bred for 38 days at three different feeding frequencies groups (feeding frequency of two times a day, TWD; three times a day, THD; and four times a day, FOD), and the expression levels of the GH/IGF axis responses to feeding frequency were determined by quantitative real-time PCR. In addition, the full-length of the Coding Sequences of IGF I and IGF II genes (489-bp and 660-bp, respectively), were cloned and analyzed from Chinese sturgeon the first time. Multiple sequence alignments of IGFs revealed that Chinese sturgeon are high sequence identity to IGFs from other species. The phylogenetic relationships based on the IGF I and IGF II amino acid sequences were consistent with the traditional classification. After 38 days of growth, the three different feeding frequencies groups of Chinese sturgeon had no significant difference of body length, body weight, specific growth rate, the survival rate, the rate of weight gain and the condition factor. However, the relative expression of Chinese sturgeon GH in the pituitary decreased with increasing feeding frequency. The relative expression of Chinese sturgeon GHR in liver and skeletal muscle was deceased with increasing feeding frequency, while the relative expression of GHR in stomach and intestines at THD group was significantly higher than that of at TWD group and FOD group (p p p p

Citrobacter freundii is one of the important bacterial diseases responsible for disease outbreaks to wild and cultured fishes globally. However, no known empirical research has focused on exploring relationships between immune response after C. freundii infection in sturgeons. In this study, C. freundii was isolated and identified from artificially breeding Chinese sturgeon, and global measurement of transcriptome response to C. freundii infection in head-kidney and spleen of A. sinensis were conducted to the acknowledgement of the potential mechanisms of pathogen-host interaction triggered by the bacterial infection. In total, differentially expressed genes which significantly associated with immune responses were found to be participated in antigen processing and presentation (MHC I, MHC II, HspA1, Hsp90A, Hsp70, CTSL, and CTSE), and acute phase response (serotransferrin and CP), as well as changing of other immune-related cytokine, such as chemokine and interferon, which proving their reacting and regulatory role during the response of thehost against C. freundii infection in fish. C. freundii can cause serious disease in sturgeon species was first reported in this study, and innate immune responses to C. freundii infection in this study will be conducive to understand the defense mechanisms and making appropriate prevention strategies in A. sinensis aquaculture operations.

Precise, automatic and reliable position control of micro-objects such as single particles, biological cells or bio-organisms is critical for applications in biotechnology and tissue engineering. However, conventional acoustofluidic techniques generally lack reliability and automation capability thus are often incapable of building an efficient and automated system where the biological cells need to be precisely manipulated in three dimensions (3D). To overcome these limitations, we developed an acoustofluidic closed-loop control system which is combined with computer vision techniques and standing surface acoustic waves (SSAWs) to implement selective, automatic and precise position control of an object, such as a single cell or microparticle in a microfluidic chamber. Position of the object is in situ extracted from living images that are captured from a video camera. By utilizing the closed-loop control strategy, the object is precisely moved to the desired location in 3D patterns or along designed trajectories by manipulating the phase angle and power signal of the SSAWs. Controlling of breast cancer cells has been conducted to verify the principle and biocompatibility of the control system. This system could be employed to build an automatic system for cell analysis, cell isolation, self-assembling of materials into complex microstructures, or lab-on-chip and organ-on-chip applications. Ministry of Education (MOE) Nanyang Technological University The authors gratefully acknowledge the support of (i) Nanyang Technological University and the Ministry of Education of Singapore through a PhD Scholarship; (ii) the UK Engineering and Physical Sciences Research Council (EPSRC) grants EP/P018998/1; (iii) Special Interesting Group of Acoustofluidics funded by UK Fluids Network (EP/N032861/1).

The Chinese sturgeon (Acipenser sinensis) is an anadromous fish distributed in the Yangtze River and the East China Sea. In this study, we report the novel finding of cleft palates in Chinese sturgeons derived from artificial fertilization. To explore the genetic basis of palate malformation in A. sinensis, Illumina RNA-seq technology was used to analyze the transcriptome data of farmed Chinese sturgeons with normal palates and cleft-palates. Raw reads were obtained and assembled into 808,612 unigenes, with an average length of 509.33 bp and an N50 of 574 bp. Sequence similarity analyses against four public databases (Nr, UniProt, KEGG, and COGs) found 158,642 unigenes that could be annotated. GABAergic synapses and TGF-β signal pathways were the two most enriched pathways with high Rich Factors in the analyses of differentially expressed genes. In these two signal pathways, six genes (GABRA4, GS, GNS, S6K, PITX2, and BMP8) were found as candidate cleft-palate genes in Chinese sturgeon. These findings contribute to our understanding of cleft palate genetics in sturgeon, while simultaneously adding to our knowledge about craniofacial development.

Silver nanoparticles-attached zinc oxide (ZnO) nanorods on polyacrylonitrile/indium tin oxide (Ag-ZnO-PAN/ITO) nanofibres with three-dimensional (3D) hierarchical nanostructures were facilely prepared via electrospinning followed by hydrothermal synthesis of ZnO nanorods and silver attachment with the assistance of polydopamine (PDA) thin layer. ZnO nanorods with different dimensions and silver nanoparticles with different loadings were introduced. The morphologies and structures of the nanostructures were studied by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and thermogravimetric analyzer (TGA). The effect of Ag-ZnO-PAN/ITO nanofibres with different loadings of ZnO nanorods and silver nanoparticles on their antibacterial activity against Escherichia coli and Pseudomonas aeruginosa was investigated. It is shown that the hybrid nanofibres exhibit excellent antibacterial capability. The hierarchical structure benefits the attachment of a large amount of silver nanoparticles due to its large surface area, and the deposited PDA thin layer helps improve the structure stability for long-term antibacterial application through firmly anchoring silver nanoparticles onto the surface. This work offers an effective and straightforward “all-solution” strategy to incorporate Ag-ZnO combination into nanofibrous PAN. Moreover, the hierarchical nanostructure integrates the antibacterial function of both ZnO and silver, and renders itself a promising candidate as for sportswear and equipment. Keywords: Zinc oxide, Silver, Nanofibres, Electrospinning, Polydopamine, Antibacterial

With the continuous development of human society and urban construction, exploring sustainable power sources of monitor and protection systems for city’s infrastructure is becoming more and more urgent. Scavenging ambient fluid flow energy to efficiently and conveniently power electric devices has potential applications for pipeline systems, especially in remote areas. Here, a multi-cylinder-based hybridized electromagnetic-triboelectric nanogenerator (MCNG) is reported to harvest two types of fluid energy at the same time to double the working frequency of the hybrid NG. The introduction of Nylon film effectively improved the durability and output performance. And the structure to transmit external mechanical through magnetic coupling is easy to packaging and assembly, which provides a stable inner environment. Moreover, the hybrid nanogenerator was demonstrated to effectively harvest energy from wind and water flow to power 1075 LEDs and a temperature sensor. Furthermore, a self-powered wireless pipeline leakage monitoring system and a self-powered cathodic protection system based on the MCNG are developed and illustrated. This work provides a prospective strategy for hybrid nanogenerator to improve working frequency and output stability for practical applications.