Search

Understanding the mineralization of coral is significant for the formation of coral reefs and paleoclimatic reconstructions. However, the fundamental mechanisms involved in biomineralization are poorly understood. A combination of Raman spectral and cross-polarized reflected light microscopy imaging was used to examine the three-dimensional spatial distribution of the skeletal ultrastructures and their associated mineral, organic, and water chemistry in coral, which enable insight into the spatial growth features of the ultrastructures and possible formation processes. A possible mechanism is proposed that controls the formation of skeletal ultrastructures, which likely involves compartmentalized calcifying cells and their related cellular activities. This could clarify the association between coral skeletal mineralization and biology, and it may be beneficial to better protection and application of coral reefs.

The strength–ductility trade-off has long been a Gordian knot in conventional metallic structural materials and it is no exception in multi-principal element alloys. In particular, at ultrahigh yield strengths, plastic instability, that is, necking, happens prematurely, because of which ductility almost entirely disappears. This is due to the growing difficulty in the production and accumulation of dislocations from the very beginning of tensile deformation that renders the conventional dislocation hardening insufficient. Here we propose that premature necking can be harnessed for work hardening in a VCoNi multi-principal element alloy. Lüders banding as an initial tensile response induces the ongoing localized necking at the band front to produce both triaxial stress and strain gradient, which enables the rapid multiplication of dislocations. This leads to forest dislocation hardening, plus extra work hardening due to the interaction of dislocations with the local-chemical-order regions. The dual work hardening combines to restrain and stabilize the premature necking in reverse as well as to facilitate uniform deformation. Consequently, a superior strength-and-ductility synergy is achieved with a ductility of ~20% and yield strength of 2 GPa during room-temperature and cryogenic deformation. These findings offer an instability-control paradigm for synergistic work hardening to conquer the strength–ductility paradox at ultrahigh yield strengths.

Obtaining the excellent resistance spot welding (RSW) properties of press hardened steel is a challenge due to the high strength with 2GPa-grade. In this study, the microstructure, mechanical properties of the RSW weld in 2GPa-grade PHS and galvanized DP980 steel were investigated. During the single pulse welding, the coarse columnar martensite is generated in the fusion zone (FZ). The low peak load is 13.2 kN for tensile-shear (TS) loading and 3.4 kN for cross-tension (CT) loading and the corresponding failure energy is 6.5 J and 16.7 J, respectively. The fracture mode under two loading conditions is partial thickness-partial pullout (PT-PP) mode. To enhance mechanical properties, the suitable double pulse welding was applied. Compared with that of the single pulse weld, double pulse weld has three special zones in FZ: the Re-melted FZ with columnar martensite, the recrystallization zone (RX-zone) with equiaxed martensite and the tempering zone (T-zone) with tempered columnar martensite. The peak load under the TS and CT loading is significantly improved by 39 pct and 44 pct and the failure energy for TS loading is enhanced by 38 pct and 186 pct for CT loading, respectively. The failure mode changes from the PT-PP mode to the pullout failure (PF) mode for CT loading in double pulse welds.

Ferroptotic cancer therapy is promising in many scenarios where traditional cancer therapies show a poor response. However, certain types of cancers lack the long-chain acyl-CoA synthetase 4 (ACSL4), a key modulator of ferroptosis, resulting in therapy resistance and tumor relapse. Because ACSL4 is in charge of the synthesis of ferroptotic lipids (e.g., arachidonoylphosphatidylethanolamine/PE-AA), we postulated that direct delivery of PE-AA may reverse ferroptosis resistance induced by ACSL4 deficiency. To further increase the ferroptosis sensitivity, we employed the ferrocene-bearing polymer micelles to co-load PE-AA with an FDA-approved redox modulator, auranofin (Aur), targeting the thioredoxin reductase. The presence of ferrocene enabled triggered cargo release and iron production, which can sensitize ferroptosis by boosting autoxidation-mediated PE-AA peroxidation. The micellar system could impair redox homeostasis and induce lipid peroxidation in ACSL4-deficient MCF-7 cells. Moreover, the tailored micelles potently induced ferroptosis in MCF-7 tumors in vivo, suppressed tumor growth, and increased the mice’s survival rate. The current work provides a facile means for reversing the ferroptosis resistance in ACSL4-deficient tumors.

Due to their unique precipitation behavior, magnesium-rare earth (Mg-RE) alloys exhibit excellent strength and high thermal stability. However, owing to the negative blocking effect of precipitation on dislocation slipping, the plasticity and ductility of Mg-RE alloys become deteriorate after aging treatment. In this work, a novel strategy to improve the combination of strength and ductility by designing a laminate heterostructured Mg alloy is proposed. High-pressure torsion (HPT) processing is employed to fabricate a clean and well-bonded interface between MgGdYAg and MgAg alloys. The two alloys have huge differences in precipitation hardening, and ductility is improved due to two facts. For one thing, the density of the second phases in the MgAg alloy is much lower than that of MgGdYAg alloy; for another, the non-basal 〈c+ a〉 slipping is continuously activated during deformation. Through this mechanism, the uniform elongation of the heterostructured MgAg/MgGdYAg/MgAg alloy is improved to 7.1%.

Carbonate‐associated sulfate (CAS) δ34S values (δ34SCAS) are generally assumed to reflect S isotopic composition of paleo‐seawater and have been extensively used to reconstruct secular variations in seawater sulfate concentrations during the geological past. However, it has often been documented that δ34SCASrecords are incompatible with seawater sulfur isotopes (20.9 ± 0.1%, 2σ) determined from other archives, such as sulfate evaporites and barite (both of which may also display inconsistencies). A possible explanation for this discrepancy is that δ34SCASvalues can be easily altered by atmospheric sulfate and sulfide re‐oxidation. However, the specific influence of biological factors (vital effects, common in biogenic carbonates) on CAS S isotopic composition remains unresolved, particularly at microscale levels. To elucidate these effects on δ34SCAS, S isotopic profiles were analyzed across two skeletal transects of two modern deep‐sea corals (gorgonia) using a novel secondary‐ion mass spectrometry method. Strong S isotopic fractionation was observed in calcitic skeletons from the most 34S‐depleted center (δ34S = ∼19‰), increasing outward to a relatively constant 22.5‰ in gorgonia sp. coral and 21.6‰ in bamboo coral, suggesting that vital effects are much larger than previous estimated (∼±1‰ fractionation from seawater). Oxygen isotopic and Mg, S, O elemental compositions, and Raman spectral and crystal morphological features indicate that processes such as pH control, Rayleigh fractionation, and organic effects are precluded as causes of such fractionation. Instead, vital effects associated with kinetic processes related to surface entrapment seem plausible as controls on S isotopic fractionations in the coral. This novel method is significant for gaining insights into vital effects, assessing the reliability of biogenic carbonates as high‐resolution environmental archives of S isotopes, and understanding the fundamental mechanisms governing biomineralization. The δ34S values of carbonate‐associated sulfate (CAS) serve as crucial indicators of past environmental conditions, providing insights into historical variations in seawater sulfate and atmospheric oxygen levels. It is commonly assumed that δ34SCASclosely reflects seawater sulfate, except for severely altered samples. However, analysis of S isotopic profiles across two skeletal transects of modern calcitic deep‐sea corals (gorgonia sp.coral and bamboo coral) using a newly developed in situ method based on secondary‐ion mass spectrometry, reveals significant isotopic fractionation. The most 34S‐depleted center (δ34S = ∼19‰) increases outward to a relatively constant value of 22.5‰ for gorgonia sp.coral and 21.6‰ for bamboo coral. These findings suggest that vital effects play a notable role in δ34SCASfractionation, challenging the previous consensus of ∼±1‰. Further investigation, incorporating multiple indices and skeletal δ18O, indicates that vital effects associated with kinetic processes related to surface entrapment contribute to this fractionation. These insights shed light on the processes driving S–O isotopic fractionation in biogenic carbonates, bolstering their utility in reconstructing paleo‐oceanographic conditions. Development of in situ carbonate S isotopic analysis using secondary‐ion mass spectrometryCommonly observed anomalous low δ34S and δ18O values in the axial skeleton of deep‐sea gorgonia coralsContribution of kinetic‐associated vital effects to significant Carbonate‐associated sulfate sulfur isotopic fractionation, supported by multiple geochemical indices Development of in situ carbonate S isotopic analysis using secondary‐ion mass spectrometry Commonly observed anomalous low δ34S and δ18O values in the axial skeleton of deep‐sea gorgonia corals Contribution of kinetic‐associated vital effects to significant Carbonate‐associated sulfate sulfur isotopic fractionation, supported by multiple geochemical indices

This research introduces a novel approach to reconstruct sea surface temperature (SST) by developing a universal coral thermometer using machine learning (ML) algorithms on monthly resolved Poritescoral proxies and SST data. A total of 1,202 data sets from 19 corals, covering SSTs ranging from 21.5 to 31.5°C, with proxies including Sr/Ca, Mg/Ca, Li/Mg, U/Ca, and B/Ca ratios were analyzed. The data were divided into four sub‐datasets by regional and taxon constraints. An exhaustive analysis was conducted, training 1,612 models using various proxy combinations and ML strategies to assess the impact of the non‐SST effect on the universality of ML models. The results indicated that the non‐SST effect is more significantly attributed to regional variations than to taxon differences, underscoring the importance of regional factors in Poritescoral proxy‐based SST reconstructions. Sr/Ca and Li/Mg proxies were identified as the most indicative of SST, showing clearer relationships with temperature than other proxies. Non‐linear approaches achieved a Root Mean Square Error (RMSE) of less than 0.90°C, which further decreased to 0.72°C upon incorporating specific regional and taxon constraints. In an independent test set focusing exclusively on Li/Mg and Sr/Ca proxies, the tree‐based algorithms particularly excelled, achieving an average RMSE improvement of at least 0.52°C over the Universal Multi‐Trace Element Calibration Scheme and the Li/Mg empirical equation. This research underscores the potential of applying ML to coral‐based SST reconstructions, especially highlighting the effectiveness of tree‐based algorithms and the suitability of Sr/Ca and Li/Mg proxies for accurate temperature estimations. A universal coral thermometer was developed using machine learning (ML) on Poritescoral proxies, enhancing paleo sea surface temperature (SST) reconstruction accuracyLi/Mg and Sr/Ca proxies were identified as the most effective for SST reconstructions, showcasing clearer relationships with SSTTree‐based ML models outperformed others in predicting SST, advocating their use when Sr/Ca and Li/Mg proxies are available A universal coral thermometer was developed using machine learning (ML) on Poritescoral proxies, enhancing paleo sea surface temperature (SST) reconstruction accuracy Li/Mg and Sr/Ca proxies were identified as the most effective for SST reconstructions, showcasing clearer relationships with SST Tree‐based ML models outperformed others in predicting SST, advocating their use when Sr/Ca and Li/Mg proxies are available

With resistance to current agricultural fungicides rising, a great need has emerged for new antifungals with unexploited targets. In response, we report a novel series of diazaborines with potent activity against representative fungal plant pathogens. To identify their mode of action, we selected for resistant isolates using the model fungus Saccharomyces cerevisiae. Whole-genome sequencing of independent diazaborine-resistant lineages identified a recurring mutation in ERG25,which encodes a C-4 methyl sterol oxidase required for ergosterol biosynthesis in fungi. Haploinsufficiency and allele-swap experiments provided additional genetic evidence for Erg25 as the most biologically relevant target of our diazaborines. Confirming Erg25 as putative target, sterol profiling of compound-treated yeast revealed marked accumulation of the Erg25 substrate, 4,4-dimethylzymosterol and depletion of both its immediate product, zymosterol, as well as ergosterol. Encouraged by these mechanistic insights, the potential utility of targeting Erg25 with a diazaborine was demonstrated in soybean-rust and grape-rot models of fungal plant disease.

Understanding the intricate regulatory mechanisms underlying the anthocyanin content (AC) in fruits and vegetables is crucial for advanced biotechnological customization. In this study, we generated high-quality haplotype-resolved genome assemblies for two mulberry cultivars: the high-AC ‘Zhongsang5801’ (ZS5801) and the low-AC ‘Zhenzhubai’ (ZZB). Additionally, we conducted a comprehensive analysis of genes associated with AC production. Through genome-wide association studies (GWAS) on 112 mulberry fruits, we identified MaVHAG3, which encodes a vacuolar-type H+-ATPase G3 subunit, as a key gene linked to purple pigmentation. To gain deeper insights into the genetic and molecular processes underlying high AC, we compared the genomes of ZS5801 and ZZB, along with fruit transcriptome data across five developmental stages, and quantified the accumulation of metabolic substances. Compared to ZZB, ZS5801 exhibited significantly more differentially expressed genes (DEGs) related to anthocyanin metabolism and higher levels of anthocyanins and flavonoids. Comparative analyses revealed expansions and contractions in the flavonol synthase (FLS) and dihydroflavonol 4-reductase (DFR) genes, resulting in altered carbon flow. Co-expression analysis demonstrated that ZS5801 displayed more significant alterations in genes involved in late-stage AC regulation compared to ZZB, particularly during the phase stage. In summary, our findings provide valuable insights into the regulation of mulberry fruit AC, offering genetic resources to enhance cultivars with higher AC traits.

• The CrCoNi medium-entropy alloy shows a superior strength and ductility synergy, Charpy impact energy (A K), and fracture toughness at cryogenic temperatures as compared to both 316L and 316LN stainless steels. • These three alloys all rely heavily on shear transformations upon plastic straining, with deformation twinning dominating in CrCoNi while martensitic transformation involved in stainless steels. We systematically compared the mechanical properties of CrCoNi, a recently emerged prototypical medium-entropy alloy (MEA) with face-centered-cubic (FCC) structure, with hallmark FCC alloys, in particular, the well-known austenitic 316L and 316LN stainless steels, which are also concentrated single-phase FCC solid solutions and arguably next-of-kin to the MEAs. The tensile and impact properties, across the temperatures range from 373 K to 4.2 K, as well as fracture toughness at 298 K and 77 K, were documented. From room temperature to cryogenic temperature, all three alloys exhibited similarly good mechanical properties; CrCoNi increased its tensile uniform elongation and fracture toughness, which was different from the decreasing trend of the 316L and 316LN. On the other hand, the stainless steels showed higher fracture toughness than CrCoNi at all temperatures. To explain the differences in macroscopic mechanical properties of the three alloys, microstructural hardening mechanisms were surveyed. CrCoNi MEA relied on abundant mechanical twinning on the nanoscale, while martensitic transformation was dominant in 316L at low temperatures. The deformation mechanisms in the plastic zone ahead of the propagating crack in impact and fracture toughness tests were also analyzed and compared for the three alloys. [ABSTRACT FROM AUTHOR]

Complex concentrated solutions of multiple principal elements are being widely investigated as high- or medium-entropy alloys (HEAs or MEAs)1–11, often assuming that these materials have the high configurational entropy of an ideal solution. However, enthalpic interactions among constituent elements are also expected at normal temperatures, resulting in various degrees of local chemical order12–22. Of the local chemical orders that can develop, chemical short-range order (CSRO) is arguably the most difficult to decipher and firm evidence of CSRO in these materials has been missing thus far16,22. Here we discover that, using an appropriate zone axis, micro/nanobeam diffraction, together with atomic-resolution imaging and chemical mapping via transmission electron microscopy, can explicitly reveal CSRO in a face-centred-cubic VCoNi concentrated solution. Our complementary suite of tools provides concrete information about the degree/extent of CSRO, atomic packing configuration and preferential occupancy of neighbouring lattice planes/sites by chemical species. Modelling of the CSRO order parameters and pair correlations over the nearest atomic shells indicates that the CSRO originates from the nearest-neighbour preference towards unlike (V−Co and V−Ni) pairs and avoidance of V−V pairs. Our findings offer a way of identifying CSRO in concentrated solution alloys. We also use atomic strain mapping to demonstrate the dislocation interactions enhanced by the CSROs, clarifying the effects of these CSROs on plasticity mechanisms and mechanical properties upon deformation.

• The laminate HMDP steels are produced by a combination of warm rolling and intercritical annealing. • Warm rolling accelerates cementite spheroidization, which enhances the kinetics of austenite formation. • The laminate HMDP steels present superior strength-ductility synergy than the non-laminate counterpart. • The high ductility of laminate HMDP steels is owed to the heterostructure with laminate ferrite surrounded by martensite. The steels with excellent strength and ductility are expected to be achieved by tailoring the microstructural features. In this work, laminate dual-phase (DP) steels with high martensite content (laminate HMDP steels) were produced by a combination of warm rolling and intercritical annealing. Influence of rolling strain and annealing temperature on the microstructural evolution and mechanical properties of laminate HMDP steels were systematically studied. The strength of HMDP steels was significantly improved to ∼1.6 GPa associated with a high uniform elongation of 7%, as long as the laminate structure is maintained. The strengthening and ductilizing mechanisms of laminate HMDP steels are discussed based on the influence of laminate structure and the high martensite content, which promote the development of internal stresses and can be correlated to the Bauschinger effect as measured by the cyclic loading-unloading-reloading experiments. Detailed transmission electron microscopy (TEM) observation was applied to characterize the dislocation structure in the deformed ferrite. [ABSTRACT FROM AUTHOR]

There are great differences in physiological and biological functions between animals of different sexes. However, whether there is a consensus between sexes in duck intestinal development and microorganisms is still unknown. The current study used Nonghua ducks to estimate the effect of sex on the intestine by evaluating differences in intestinal growth indexes and microorganisms. The intestines of male and female ducks were sampled at 2, 5, and 10 wk from the duodenum, jejunum, ileum, and cecum. Then, the intestinal length and weight were measured, the morphology was observed with HE staining, and the intestinal content was analyzed by 16S rRNA sequencing. The results showed that male ducks have shorter intestinal lengths with higher relative weights/relative lengths. The values of jejunal villus height (VH)/crypt depth (CD) of female ducks were significantly higher at 2 wk, whereas the jejunal VH/CD was significantly lower at 10 wk. There was obvious separation of microorganisms in each intestinal segment of ducks of different sexes at the 3 time periods. The dominant phyla at different stages were Firmicutea, Proteobacteria, Bacteroidetes, and Actinobacteria. The duodenal Chao index at the genus level of male ducks was significantly higher at 10 wk than that of female ducks. Significantly different genera were found only in the jejunum, and the abundances of Escherichia_Shigella, Pseudomonas, Clostridium_sensu_stricto_1, Sphingomonas,and Desulfovibrioin male ducks were higher than those in female ducks, whereas the abundance of Rothiawas lower, and the abundance of viral infectious diseases, lipid metabolism, metabolism of terpenoids and polyketides, parasitic infectious diseases, xenobiotic biodegradation and metabolism, cardiovascular disease, and metabolism of other amino acids in male ducks were higher than that in female ducks, whereas gene folding, sorting and degradation pathways, and nucleotide metabolism were lower. This study provides a basic reference for the intestinal development and microbial symbiosis of ducks of different sexes.

‘Huabai 1’ is a novel albino tea germplasm that has a stable albino phenotype and prolonged albino period. In this study, widely targeted metabolomics was employed to analyze the metabolic profile of ‘Huabai 1’, and compare metabolites between albino shoots of ‘Huabai 1’ (HBW) and albino shoots of the broadest cultivated cultivar ‘Baiye 1’ (BYW). A total of 359 differential metabolites were identified in ‘Huabai 1’. Comparative analysis of differential metabolites revealed that 83 and 161 differential metabolites were specific for HBW and BYW, respectively. The phenylpropanoid and flavonoids biosynthesis are the key metabolic pathways, contributing to the color change in ‘Huabai 1’, while the purine metabolism and lipid-related metabolites may play important roles in regulating albinism in ‘Baiye 1’. Comparative analysis of amino acids and catechins revealed that the umami taste of albino tea may be due to the internal balance of amino acid components and the decrease in phenol-ammonia ratio. In addition, lipid-related metabolites, the main contributors to the aroma of tea, were significantly enriched in BYW, while, HBW possess higher antioxidative components than that of BYW, such as apigenin and genistein etc., suggesting that the ‘Huabai 1’ may have high prospects in commercialization and future breeding programs.

In the face of diverse challenges like global warming, ocean acidification, and human activities, the world's coral reefs are confronting a severe ecological crisis. Understanding the historical coevolution of corals with their environment and their resilience to current climate change is crucial for protecting these ecosystems and predicting their future. In this context, metal stable isotopes in corals present a novel and alternative methodology. Their significant fractionation during coral biological processes, persistent presence in coral skeletons, and relatively straightforward sources make them a valuable tool. However, the complexity of coral biology necessitates a deeper investigation into the fundamental mechanisms behind the isotopic fractionation of these biologically utilized metal elements. A comprehensive and systematic study of the roles of metal stable elements in coral biological processes is essential. This includes examining the fractionation of metal isotopes across different parts of the corals, such as tissues, zooxanthellae, and skeletons. To achieve these goals, multidisciplinary collaborations are essential. They should focus on several key areas: interpreting metal stable isotopes data in the context of coral physiology and ecology; conducting controlled laboratory experiments on coral cultivation; engaging in comparative studies with inorganically precipitated aragonites; and developing a holistic understanding within the framework of coral biomineralization models. Coral reefs around the world are facing serious threats from global warming, ocean acidification, and human activities. Understanding how corals have historically adapted to the environment and climate changes can provide useful information for protecting coral reefs and predicting their future. An innovative approach to this is examining stable isotopes of specific metal elements found in corals. These isotopes act as long‐lasting markers that can trace coral life cycles and reveal how corals adjust to changing climates from a geochemical standpoint. However, understanding how these metal stable isotopes vary in different parts of the coral, such as in tissues, symbiotic algae, and skeletons, is complex and needs further research. This calls for a united effort from both geochemists and coral biologists. Together, they can study these metal stable isotopes in relation to coral biology and ecology, perform detailed experiments on coral growth in the lab, compare coral skeletons to similar non‐living materials, and develop comprehensive models to explain how corals form their skeletons. This collaborative approach is vital for a deeper insight into coral resilience and for effective coral reef conservation. Deciphering coral adaptability to climate and environmental change is pivotal for predicting reef evolutionBio‐utilized metal stable isotopes offer insight into coral adaptation to climate and environmental changesProbing metal stable isotopes in corals requires interdisciplinary collaboration and integrated methods Deciphering coral adaptability to climate and environmental change is pivotal for predicting reef evolution Bio‐utilized metal stable isotopes offer insight into coral adaptation to climate and environmental changes Probing metal stable isotopes in corals requires interdisciplinary collaboration and integrated methods

Ferroptotic cancer therapy has been extensively investigated since the genesis of the ferroptosis concept. However, the therapeutic efficacy of ferroptosis induction in heterogeneous and plastic melanoma has been compromised, because the melanocytic and transitory cell subpopulation is resistant to iron-dependent oxidative stress. Here, we report a phenotype-altering liposomal nanomedicine to enable the ferroptosis-resistant subtypes of melanoma cells vulnerable to lipid peroxidation via senescence induction. The strategy involves the ratiometric coencapsulation of a cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor (palbociclib) and a ferroptosis inducer (auranofin) within cRGD peptide-modified targeted liposomes. The two drugs showed a synergistic anticancer effect in the model B16F10 melanoma cells, as evidenced by the combination index analysis (<1). The liposomes could efficiently deliver both drugs into B16F10 cells in a targeted manner. Afterward, the liposomes potently induced the intracellular redox imbalance and lipid peroxidation. Palbociclib significantly provoked cell cycle arrest at the G0/G1phase, which sensitized auranofin-caused ferroptosis through senescence induction. Meanwhile, palbociclib depleted intracellular glutathione (GSH) and reduced nicotinamide adenine dinucleotide phosphate (NADPH), further boosting ferroptosis. The proof-of-concept was also demonstrated in the B16F10 tumor-bearing mice model. The current work offers a promising ferroptosis-targeting strategy for effectively treating heterogeneous melanoma by manipulating the cellular plasticity.

High‐precision uranium‐thorium (U‐Th) dating of dead branching corals from Luhuitou reef, Sanya, northern South China Sea indicates that the reef framework grew episodically over the past 7,000 years. Episodes of coral reef growth (“switch‐on” phases) occurred in response to regional warming during the mid‐Holocene Climate Optimum, Medieval Warm Period, and Current Warm Period, when the East Asian summer monsoon was strong and the East Asian winter monsoon was weak. In contrast, episodes when reef growth dramatically slowed or ceased (“switch‐off” phases) occurred during comparatively cold periods (e.g., Dark Age Cold Period and Little Ice Age) and are linked to abrupt weakening of the East Asian summer monsoon and concurrent strengthening of the East Asian winter monsoon. In the context of global warming, the northern South China Sea may become an important refugium for coral reef growth of up to 2 °C above present, but only if local anthropogenic pressures are reduced. Understanding the response of coral reef growth to past warm periods allows better predictions of the response of coral reefs to future climate change and evaluations of the potential for the locality to act as climate change refugia for coral reefs in the 21st century. We identify abrupt coral reef recovery in the northern South China Sea (SCS) since the last century (especially post‐1960 CE), indicating that the Current Warm Period is an optimal episode for reef growth in the northern SCS. As our results suggest that expansive coral growth occurred in the mid‐Holocene when sea surface temperatures were up to 2 °C higher than present, the northern SCS may represent critical refugia for future reefs in the 21st century. U‐Th dating of corals reveals episodic reef growth in the northern South China Sea over the past 7,000 yearsEnhanced winter cooling associated with strengthened EAWM is the dominant stressor inhibiting reef growthReefs in the northern South China Sea are potential coral refugia in the context of global warming

Major and trace elements, Sr and Nd isotopes of bulk particles from the SCS‐NW and SCS‐N‐03 traps were studied to trace the provenance of sinking particles in the northern South China Sea (SCS). About 63% of biogenic materials and most of lithogenic materials from the SCS‐NW trap may be contributed from resuspended sediments, and more biogenic materials are collected in winter than in summer. The immobile‐element discrimination diagrams also indicate that the lithogenic materials of particles are, to a large degree, from local seafloor sediments, and that the lithogenic materials of particles from SCS‐N and SCS‐W traps have seasonal variations. Sr isotopes (87Sr/86Sr and δ88Sr) of bulk particles are significantly influenced by biogenic materials and cannot be used in provenance tracing. In contrast, Nd isotopes are ideal tools to trace particle provenance. However, the traditional Nd isotope (143Nd/144Nd) shows no statistical difference on the particles of the SCS‐NW and SCS‐N‐03 traps, making it unable to identify their provenance. Fortunately, the stable Nd isotope, ε146Nd, shows different correlation trends to ε143Nd in these two traps, suggesting that stable Nd isotope can potentially identify the sources of lithogenic materials in the northern SCS. Our results indicate that distribution and transportation of sinking particles are controlled by currents of the SCS mainly driven by the East Asian Monsoon. As the largest semi‐enclosed marginal sea in the west Pacific, the South China Sea (SCS) is supplied with a large amount of suspended sediments from its surrounding continents and islands. Studies on sedimentary process and source of sediments in the SCS have long been carried out, but no consensus has been reached yet. This study presents elemental and Sr‐Nd isotope geochemistry of sinking particles from the northern SCS. According to fluxes and element concentrations of sinking particles, we find that resuspended sediments are an important contributor to sinking particles in the SCS. The relationship between trace elements of sinking particles and offshore surface sediments indicates that these resuspended sediments may be derived from continental shelves. The distribution and transportation of sinking particles are influenced by hydrological conditions of the SCS mainly driven by the East Asian monsoon. This study also reveals that stable Nd isotope could be a powerful tool in tracing sediment provenances in the northern SCS. Therefore, our results will improve the understanding of sediment transportation and sedimentary processes in the northern SCS. Resuspended sediments are an important contributor of the sinking particles collected by sediment traps, especially deep trapsProvenance and seasonal variation of sinking particles can be identified by immobile‐element discrimination diagramsThe stable Nd isotopic composition coupled with conservative trace elements is a potential tool in provenance tracing

The 4.2 ka BP Event is an abrupt climate change that might have contributed to the collapse of ancient civilizations and marks the transition between the mid‐ and late‐Holocene. Despite considerable research on this event, our understanding remains primarily based on terrestrial paleoclimate reconstructions, leaving a significant gap in understanding the role of the ocean in this event. Here, we present paired sea surface temperature (SST) and seawater δ18O reconstructions based on four fossil corals from the South China Sea. Our results demonstrate that the climate during the event was cooler, and there were meridional dry‐wet patterns in East Asia, indicating a weakened summer monsoon. Furthermore, our examination of additional coral records from the Pacific and Indian Oceans suggests that low‐latitude forcing (i.e., SST anomalies in the tropical Pacific) plays a crucial role in driving hydrology shifts in East Asia over the 4.2 ka BP interval. Around 4,200 years ago, a major climate event occurred, resulting in a global megadrought that might have caused the collapse of ancient civilizations. However, most evidence for this event comes from land‐based paleoclimate studies, leaving a gap in our understanding of how it impacted the ocean. In this study, we analyzed fossil coral samples from the South China Sea and found that the area was cooler and wetter during the event. While the cooling appears to have been consistent across East Asia, the hydrological changes exhibited a meridional pattern, with Central China also experiencing wetter conditions while North and South China were dry. By examining coral records from the Pacific and Indian Oceans, we concluded that the Central Pacific El Niño was likely occurring during this event, weakening the East Asian Summer Monsoon and causing the associated climate and hydrology changes in East Asia. Paired fossil coral Sr/Ca and δ18O records indicate a cold and wet climate in the northern South China Sea during the 4.2 ka BP eventCoral and terrestrial reconstructions reveal consistent cooling but meridionally‐varied hydrological changes in East Asia around 4.2 ka BPLow‐latitude sea surface temperature anomalies in tropical Pacific significantly contribute to the shift in hydroclimate in East Asia Paired fossil coral Sr/Ca and δ18O records indicate a cold and wet climate in the northern South China Sea during the 4.2 ka BP event Coral and terrestrial reconstructions reveal consistent cooling but meridionally‐varied hydrological changes in East Asia around 4.2 ka BP Low‐latitude sea surface temperature anomalies in tropical Pacific significantly contribute to the shift in hydroclimate in East Asia

For the global oceans, the characteristics of high‐resolution climate changes during the last millennium remain uncertain because of the limited availability of proxy data. This study reconstructs climate conditions using annually resolved coral records from the South China Sea (SCS) to provide new insights into climate change over the last millennium. The results indicate that the climate of the Medieval Climate Anomaly (MCA, AD 900–1300) was similar to that of the Current Warm Period (CWP, AD 1850‐present), which contradicts previous studies. The similar warmth levels for the MCA and CWP have also been recorded in the Makassar Strait of Indonesia, which suggests that the MCA was not warmer than the CWP in the western Pacific and that this may not have been a globally uniform change. Hydrological conditions were drier/saltier during the MCA and similar to those of the CWP. The drier/saltier MCA and CWP in the western Pacific may be associated with the reduced precipitation caused by variations in the Pacific Walker Circulation. As for the Little Ice Age (LIA, AD 1550–1850), the results from this study, together with previous data from the Makassar Strait, indicate a cold and wet period compared with the CWP and the MCA in the western Pacific. The cold LIA period agrees with the timing of the Maunder sunspot minimum and is therefore associated with low solar activity. The fresher/wetter LIA in the western Pacific may have been caused by the synchronized retreat of both the East Asian Summer Monsoon and the Australian Monsoon. The fresher/wetter LIA relative to the CWP in the western Pacific may have been caused by the retreat of the East Asian Summer MonsoonMCA was similar to CWP rather than much warmer than the latter in the western PacificThe drier/saltier MCA and CWP may be associated with the variation of the Pacific Walker Circulation

Steels with outstanding mechanical properties are desired in industrial applications. Martensitic structure significantly increases the strength in low carbon steels, but usually sacrifices their ductility. In order to improve the combination of strength and ductility, a full martensitic steel was further processed by cyclic intercritical rolling to produce a novel heterogeneous lamellar structured dual-phase (HLSDP) structure. This processing route constructs a small amount of lamellar ferrite surrounded by high volume fraction of refined martensite, which is a promising heterostructure for hetero-deformation induced (HDI) hardening. The HLSDP steel shows a simultaneously improved strength and ductility (ultimate tensile strength, UTS: 1.85 GPa; uniform elongation, UE: 5.6%), comparing to the lath martensite steel (UTS: 1.68 GPa and UE: 4.1%). The superior tensile properties of HLSDP steel are attributed to the higher strain hardening ability, which is related to the significant HDI hardening. Due to the deformation incompatibility between the soft zone (ferrite) and hard zone (martensite), strain partitioning is occurred during plastic deformation. In addition, micro digital image correlation (μ-DIC) analysis reveals the evolution of strain field during deformation. A significant strain gradient is produced near the interface of ferrite and martensite in the HLSDP steel.

The typical features of the mid‐Holocene can be used to better understand present‐day climate conditions and the potential trends of future climate change. The surface conditions, including sea surface temperature (SST) and sea surface salinity (SSS), of the South China Sea (SCS) are largely controlled by the East Asian monsoon system. Surface water conditions reconstructed from coral proxies can be used to study the evolution of the East Asian monsoon during the mid‐Holocene. However, there are some discrepancies among existing coral‐based studies regarding whether the mid‐Holocene sea surface water was much saltier than the present day surface waters. Based on paired Sr/Ca and δ18O of modern and three fossil corals, this paper reconstructs the patterns of seasonal variation in SSS during the mid‐Holocene in the northern SCS. The Δδ18O records (a proxy for SSS) derived from the three fossil corals were all heavier than that from the modern coral, which suggests the presence of more saline surface waters during the mid‐Holocene in the northern SCS. These results are consistent with previous studies based on records reconstructed from coral and foraminifera, as well as from numerical simulations. Reduced rainfall caused by the strengthened Asian Monsoon and/or the northward shift of the intertropical convergence zone during the mid‐Holocene would explain the increased salinity of the surface waters of the northern SCS. The findings presented here clarify the discrepancies among previous studies and confirm the existence of saltier surface waters in the northern SCS during the mid‐Holocene. Coral Δδ18O records indicate more saline mid‐Holocene surface waters in the South China SeaIncreased salinity may be caused by strengthened Asian Monsoon and/or northward shift of the ITCZCoral Δδ18O is a better tool for reconstructing sea surface salinity than coral δ18O in the South China Sea

Long‐term seawater pH records are essential for evaluating the rates of ocean acidification (OA) driven by anthropogenic emissions. Widespread, natural decadal variability in seawater pH superimposes on the long‐term anthropogenic variations, likely influencing the OA rates estimated from the pH records. Here, we report a record of annual seawater pH estimated using the δ11B proxy over the past 159 years reconstructed from a Poritescoral collected to the east of Hainan Island in the northern South China Sea (SCS). By coupling this time series with previously reported long‐term seawater pH records in the West Pacific, the decadal variability in seawater pH records and its possible driving mechanisms were investigated. The results indicate that large decadal variability in seawater pH has occurred off eastern Hainan Island over the past 159 years, in agreement with previous records. The Qiongdong upwelling system, which controls nutrient supplies, regulates surface water productivity, and is driven by the East Asian summer monsoon, is the primary control of this decadal variability, while terrestrial inputs appear not influence significantly. Meanwhile the impacts of the Pacific Decadal Oscillation (PDO) and the El Nino and Southern Oscillation (ENSO) systems on seawater pH off eastern Hainan Island is likely limited. In contrast, the PDO is the main factor to influence the decadal seawater pH variability offshore the East Australia, while the mechanism controlling the decadal seawater pH variability in Guam is not clear yet. Meanwhile, The rate of decrease in seawater pH estimated from coral records are significantly different in different regions and over different time spans, which may reflect a combination of natural decadal variability in seawater pH and long‐term variations. Therefore, understanding the mechanisms driving natural variability in seawater pH is important for improving estimates of ocean acidification rates driven by anthropogenic emissions. Coral δ11B‐based seawater pH record show large interannual to decadal variabilityMonsoon driven upwelling controls the decadal seawater pH variabilityPDO influences pH variability in the West Pacific with different effects

Existing methods of detecting the combustion phase of a diesel engine are mainly based upon high-cost in-cylinder pressure sensors. This paper presents a method of estimating the location of 75% of the mass fraction burned by using the traditional knock sensor signal. It is observed through experimental data that the knock signal has a close correlation to the location of 75% of the mass fraction burned. In this study, the knock integration is used to represent the knock intensity, while the piecewise knock integration (integration over a crank angle of 1°) is used to detect the location of 75% of the mass fraction burned. The proposed estimation method was validated using the experimental data and provided an accurate estimation of the location of 75% of the mass fraction burned. In addition, the feasibility of using the knock sensor signal to detect the biodiesel content is demonstrated using experimental data.

As an emerging additive manufacturing (AM) technique, melt electrospinning writing (MEW) is used to fabricate three-dimensional (3D) submicron filament-based scaffolds with adjustable pore size and customized structure for bone regeneration. Poly(L-lactic acid) (PLLA) scaffold with excellent biodegradability and biocompatibility is first successfully manufactured using our self-assembled MEW device. However, the ultralow cell affinity and poor bioactivity severely hamper their practical applications in bone tissue engineering. These issues are caused by the severe inherent biologically inert, hydrophobicity as well as the smooth surface of the MEW PLLA filaments. In this study, a green and robust alkaline method is applied to modify the scaffold surface and to improve the bioactivity of the MEW PLLA scaffold. Without deterioration in mechanical property but robust surface hydrophilicity, the optimal MEW PLLA scaffold shows promoted surface roughness, enhanced filament tensile modulus (~ 2 folds of the as-prepared sample), and boosted crystallizability (ultrahigh WAXD intensity). Moreover, after being cultured with KUSA-A1 cells, the 0.5 M NaOH, 2 h treated MEW PLLA scaffold exhibits higher osteoinductive ability and increased immature bone tissue amounts (3 times of controlled scaffold). Thus, the flexible surface functionalization by the specific alkaline treatment was found to be an effective method for the preparation of bioactivated MEW PLLA scaffolds with promoted bone regeneration.

The asymptotic response of donor stars in interacting binary systems to very rapid mass loss is characterized by adiabatic expansion throughout their interiors. In this limit, energy generation and heat flow through the stellar interior can be neglected. We model this response by constructing model sequences, beginning with a donor star filling its Roche lobe at an arbitrary point in its evolution, holding its specific entropy and composition profiles fixed as mass is removed from the surface. The stellar interior remains in hydrostatic equilibrium. Luminosity profiles in these adiabatic models of mass-losing stars can be reconstructed from the specific entropy profiles and their gradients. These approximations are validated by comparison with time-dependent binary mass transfer calculations. We describe how adiabatic mass-loss sequences can be used to quantify threshold conditions for dynamical timescale mass transfer, and to establish the range of post-common envelope binaries that are allowed energetically. In dynamical timescale mass transfer, the adiabatic response of the donor star drives it to expand beyond its Roche lobe, leading to runaway mass transfer and the formation of a common envelope with its companion star. For donor stars with surface convection zones of any significant depth, this runaway condition is encountered early in mass transfer, if at all; but for main-sequence stars with radiative envelopes, it may be encountered after a prolonged phase of thermal timescale mass transfer, a so-called delayed dynamical instability. We identify the critical binary mass ratio for the onset of dynamical timescale mass transfer as that ratio for which the adiabatic response of the donor star radius to mass loss matches that of its Roche lobe at some point during mass transfer; if the ratio of donor to accretor masses exceeds this critical value, dynamical timescale mass transfer ensues. In common envelope evolution, the dissipation of orbital energy of the binary provides the energy to eject the common envelope; the energy budget for this process consists essentially of the initial orbital energy of the binary and the initial self-energies of the binary components. We emphasize that, because the stellar core and envelope contribute mutually to each other's gravitational potential energy, proper evaluation of the total energy of a star requires integration over the entire stellar interior, and not just over the ejected envelope alone as commonly assumed. We show that the change in total energy of the donor star, as a function of its remaining mass along an adiabatic mass-loss sequence, can be calculated either by integration over initial and final models, or by a path integral along the mass-loss sequence. That change in total energy of the donor star, combined with the requirement that both remnant donor and its companion star fit within their respective Roche lobes, then circumscribes energetically possible survivors of common envelope evolution.

The single-degenerate model is currently a favorable progenitor model for Type Ia supernovae (SNe Ia). Recent investigations on the white dwarf (WD) + He star channel of the single-degenerate model imply that this channel is noteworthy for producing SNe Ia. In this paper, we studied SN Ia birthrates and delay times of this channel via a detailed binary population synthesis approach. We found that the Galactic SN Ia birthrate from the WD + He star channel is [?]0.3 x 10-3 yr-1 according to our standard model, and that this channel can explain SNe Ia with short delay times ([?]4.5 x 107-1.4 x 108 yr). Meanwhile, these WD + He star systems may be related to the young supersoft X-ray sources prior to SN Ia explosions.

Using a simple analytic method, we can calculate the impact effect between the ejecta of a SN Ia and its companion to survey the influence of the initial parameters of the progenitor’s system, which is useful for searching the companion in an explosion remnant. The companion models are obtained from Eggleton’s evolution code. The results are divided into two groups based on the mass-transfer stage. For a given condition, more hydrogen-rich material is stripped from the envelope of a Hertzsprung-gap companion than that of a main-sequence companion, while a larger kick velocity and a larger luminosity are gained for a main-sequence companion. The kick velocity is too low to significantly affect the final spatial velocity of the companion, which is mainly affected by the initial parameters of the progenitor systems. The spatial velocity of the stripped material has an upper limit within the range of 8000–9500 km s$^{-1}$, which only depends on the total kinetic energy of the explosion. The stripped mass, the ratio of the stripped mass to the companion mass and the kick velocity of the companion all significantly depend on the initial companion mass and the orbital period. Our model may naturally explain the spatial velocity of the star G in the remnant of Tycho’s supernova, while an energy-loss mechanism is needed to interpret its luminosity.

Boron systematics offer a unique opportunity to reveal coral calcifying fluid (CF) chemistry and seawater pH (pHsw). Here, we assess the intercolony differences of skeletal δ11B and B/Ca, and examine their variation in modern and fossil Poritesspp. collected from the east Hainan Island in the northern South China Sea (SCS), to explore changes in coral CF chemistry and pHswover the last millennium. This enables us to assess whether ocean acidification (OA) has disturbed the ability of corals to control their CF chemistry, and whether splicing coral δ11B‐pH records can trace long‐term pHswvariability. We demonstrate that coral boron systematics bear remarkable intercolony differences, with mean offset as high as 1.05‰ for δ11B and 183.1 μmol/mol for B/Ca. With this in mind, we show that fossil corals exhibit no significant difference in their CF carbonate chemistry, but all have systematically higher CF pH (pHcf, by an average of 0.12 units) and almost equivalent CF dissolved inorganic carbon (DICcf) concentration, compared to modern corals. This suggests greater OA impacts on coral pHcfbut less noticeable effects on DICcf. In addition, the ∼0.12 decline in pHcftranslates to about 0.24 reduction in pHsw, similar to another coral‐based estimate (∼0.24) from south Hainan Island, corroborating significant OA in the northern SCS since the industrial era. Nevertheless, we find that pHswin the east Hainan Island has staged a recovery from 1980 to 2010, slowing down the OA pace, highlighting important roles of other local forcing on pHswregulation. Coral boron systematics bear considerable intercolony differencesFossil corals aged within the past 1 ka have higher pHcfbut equivalent DICcflevels compared to the modern coralsSignificant post‐industrial pHswdecline occurred in the northern South China Sea Coral boron systematics bear considerable intercolony differences Fossil corals aged within the past 1 ka have higher pHcfbut equivalent DICcflevels compared to the modern corals Significant post‐industrial pHswdecline occurred in the northern South China Sea

Identifying the response of corals to anthropogenic ocean warming and acidification remains challenging, but is critical to understanding coral resilience in a changing world. Here, we report composite records of skeletal growth (1847–2014) of nine Poritesspp. colonies from the open ocean of the northern South China Sea (SCS), and paired reconstructions of sea surface temperature (SST) and seawater pH (pHsw) by examining skeletal Sr/Ca and δ11B from two of the cores. The reconstructions demonstrate that the open ocean of the northern SCS has experienced significant warming since the 1960s with an overall temperature elevation of ∼0.50°C, and persistent acidification since the 1920s with a decline rate of −0.0102 ± 0.0017 pH units per decade. Under such environmental changes, coral skeletal density represents a long‐term mild decline for the past 168 years, demonstrating significant responses to pHswand SST variation; whereas coral extension and calcification appear to be less affected, exhibiting overall increases over the studied period. However, persistent declines of both parameters are evident from the 1960s to 2014, which coincide with the sustained low pHswand elevated SST. Although the general response of coral calcification (mainly dominated by upward growth) to both warming and acidification falls just short of statistical significance over the decadal timescales, the significantly persistent decline in skeletal density and recent downtrends of calcification still underline a pessimistic situation for corals in the northern SCS. Coral reefs are particularly susceptible to climate change, but our understanding of how corals cope with it remains insufficient. Here we explore the responses of coral calcification to climate changes, by comparing paired reconstructions of coral growth and seawater environment variations. To this end, we collected nine Poritescorals from the Xisha Islands in the open ocean of the northern South China Sea (SCS) and examined their skeletal density and growth rate. Meanwhile, we adopted two of the drillcores to generate sea surface temperature and pH reconstructions from skeletal Sr/Ca and δ11B. The reconstructions show that the open ocean of northern SCS has experienced long‐term pH decline from the 1920s and significant warming since the 1960s. Under such environmental changes, we find that coral skeletal density is more susceptible to seawater pH and temperature variation, showing a long‐term decline for the past 168 years. However, it appears that coral upward growth bears certain resistance to environmental changes, showing an overall increase over the studied period. Nevertheless, during the recent decades characterized by sustained low pHswand elevated SST, we find that all the calcification parameters have begun to decline persistently, signifying a pessimistic situation for the corals in the northern SCS. Evident ocean warming and acidification over the past century in the northern South China Sea have been registered in PoritescoralsEnvironmental changes have led to a long‐term reduction in skeletal density of Poritesduring the past 168 yearsAll the calcification parameters of Poritesexhibit significant persistent declines from the 1960s Evident ocean warming and acidification over the past century in the northern South China Sea have been registered in Poritescorals Environmental changes have led to a long‐term reduction in skeletal density of Poritesduring the past 168 years All the calcification parameters of Poritesexhibit significant persistent declines from the 1960s

Climate change in the mid‐to‐late Holocene transition is very important for predicting future climate trends and understanding the relationship between abrupt climate change and the development of past human civilization. In this study, Sr/Ca ratios and δ18O records with the annual resolution extracted from four fossil corals that were growing during the Middle Bronze Age Cold Epoch (MBACE) were used to reconstruct sea surface temperature (SST) and seawater δ18O (δ18Osw) in the South China Sea (SCS) during the mid‐to‐late Holocene transition. The results indicate that the SCS experienced a rapid cooling and wetting event during the period of ∼3,500–3,800 years BP (before present year 1950). Specifically, the average SST and δ18Oswdeclined rapidly by ∼3°C and ∼0.65‰, respectively, over an interval of ∼100 years from ∼3,850 years BP to ∼3,750 years BP. This rapid climate change pattern recorded in coral archives broadly agrees with those in foraminiferal and stalagmite records from adjacent land and ocean areas. Consistent with other records from the North Atlantic, this cold event in the Asia‐Western Pacific region that occurred during the MBACE and was originally identified in the North Atlantic and European regions should have occurred at the global scale, which might be caused by changes in the Asian summer monsoon linked with solar irradiance and/or the North Atlantic climate. In addition, this rapid climate change might support the occurrence and timing of the outburst flood event during the Xia Dynasty and might have led to the fall of the Xia Dynasty. Rapid and drastic climate changes will have serious impacts on the ecological environment and the development of human society. Studies on such climate events enable to better understand the relationship between climate change and human civilization, and provide valuable materials for predicting future climate trends. There was an extremely cold event during the period of ∼3,800–3,500 years BP (before present year 1950) in the Middle Bronze Age in North Atlantic and Europe region, which had a serious impact on European civilization. We carry out high‐resolution paleoclimate reconstructions during this period by using geochemical tracers in fossil corals from the South China Sea. The results indicate that the South China Sea and even the entire Western Pacific have experienced a rapid cooling and wetting event during the period of ∼3,800–3,500 years BP and the extremely cold event during the Middle Bronze Age was global scale. In addition, the consistency between the coral records and the stalagmite records from the inner land of China suggest that a rapid cooling and drying event during the Middle Bronze Age led to the collapse of the Xia Dynasty and Emperor Yu's success in taming floods was attributed to this event. A rapid cooling event over the western Pacific region during the Middle Bronze Age was identifiedThe cooling event recorded in coral archives broadly agrees with those in foraminiferal and stalagmite recordsThe rapid cooling and drying process in inland China might have led to the collapse of the Xia Dynasty A rapid cooling event over the western Pacific region during the Middle Bronze Age was identified The cooling event recorded in coral archives broadly agrees with those in foraminiferal and stalagmite records The rapid cooling and drying process in inland China might have led to the collapse of the Xia Dynasty

Theanine (N-ethyl-γ-l-glutamine) is a special nonprotein amino acid that contributes to the umami taste and health function of tea. Although recent studies on tea breeding have focused on albino tea because of its umami taste, a factor of higher theanine concentration, the mechanism of biosynthesis of l-theanine is still unclear. In this study, four glutamine synthetase genes (CsGSs) were obtained and functionally characterized by overexpressing them in Arabidopsis. The enzyme activities of the purified CsGS proteins from Escherichia coliwere detected. The results showed that CsGSs have a dual function in the synthesis of glutamine and theanine in vivo and in vitro. Interestingly, l-theanine was abundantly synthesized in the tender shoots of “Huabai 1”. In the white tender shoots, the cytosol CsGS1.2might exhibit increased expression to compensate for decreasing levels of chloroplast CsGS2, which plays a vital role in high accumulation of theanine in “Huabai 1”. In addition, CsGS2was most likely the key l-theanine synthases in green tissues of tea. The present findings will provide basis for and considerably broaden the scope of understanding the function of CsGSsand the mechanism of l-theanine accumulation in the tender shoots of “Huabai 1”, and will be useful for breeding and screening tea with high l-theanine content.

The geochemistry preserved in massive scleractinian corals has long been used as proxies for river runoff, but its reliability in naturally extreme environment (i.e., strong hydrodynamics and intensive thermal stress) has not been tested yet. Using Poritescoral collected from the macrotidal nearshore Kimberley region of northwestern Australia, we assess the impacts of river runoff and associated changes in this extreme environment using elemental (Ba/Ca) and isotopic (δ18O and δ13C) compositions at both near monthly and annual resolutions. On the monthly timescales, significant terrestrial signatures were noted in skeletal Ba/Ca, ∆δ18O, and to a lesser extent in δ13C time series, highlighting their linkage to runoff input of Fitzroy River. However, all the geochemical time series as well as the observational coastal sea surface salinity exhibited a consistent ~1‐ to 2‐month lag with river discharge, possibly a manifestation of the sluggish water and sediments exchange in King Sound which are likely induced by strong tidal forcing. On the annual timescales, Ba/Ca follows the variation in river discharge, while freshwater supplied by both runoff and rainfall all contributed to δ18O variations. In contrast, annual δ13C is mainly dominated by the 13C Suess effect, showing a gradually downward trend. Importantly, we find that δ18O and Ba/Ca records exhibit consistent and significant long‐term trends, with δ18O being decreasing and Ba/Ca being increasing, coupled with the increased Australian monsoon, indicating that strengthened monsoon precipitation has likely brought more freshwater and sediment loads to the nearshore Kimberley region. The geochemistry preserved in massive corals living in the coastal and nearshore region can provide reliable records for terrestrial input of freshwater and sediment. This capacity is not compromised even in highly dynamic, naturally extreme reef environment as revealed in this study. Using elemental (Ba/Ca) and isotopic (δ18O and δ13C) compositions of a long‐lived Poritescoral from the nearshore Kimberley region of northwestern Australia, we evaluated the runoff‐related signals in both monthly and annual coral geochemical records, to explore their possibility being freshwater and sediments tracers. The seasonal Ba/Ca peaks are found to follow the large discharge events, and monthly ∆δ18O variation is associated with the changes of coastal salinity driving by the influx of freshwater supplied by Fitzroy River. Terrestrial signal is less manifested in skeletal δ13C records. Additionally, a consistent ~1‐ to 2‐month temporal lag was found in monthly records, a manifestation of sluggish exchange of water and sediment in this embayment which is likely induced by tidal forcing. The long‐term increase in Ba/Ca baseline ratios and decrease in δ18O from the 1920s onwar, pointed to an enhanced freshwater and sediment loads into the embayment, possibly linking to the lasting strengthening of Australian monsoon. These findings highlight that corals living in the naturally extreme environment can provide reliable records for freshwater and terrestrial sediments transport to the nearshore region by using skeletal δ18O and Ba/Ca. Terrestrial signal has been found in coral skeletal Ba/Ca, δ18O, and to a less extent in δ13CDelayed responses of seawater and coral chemistry to river discharge are likely results of tide‐dominated hydrodynamicsEnhanced freshwater and sediments transports to the nearshore Kimberley since 1920s linked to the strengthening of monsoon precipitation

Poritescorals are valuable geological archives for reconstructing past sea surface temperature (SST) in tropical oceans. Their clumped isotope compositions (indicated by Δ47values) provide a potential proxy for SST. The Δ47value in Poritescoral usually departs from thermodynamic equilibrium due to vital effects. To explore the temperature dependence of Δ47values in corals, we determined δ13C, δ18O, and Δ47values in two modern Poritescorals from the South China Sea. Our results indicate no intercolony or intracolony biases in Δ47values on annual timescales. However, on seasonal timescales, Δ47enrichment associated with δ13C depletion is observed at an intracolony level. This cannot be explained by incomplete hydration and/or hydroxylation of metabolic CO2; instead, we interpret this new pattern of isotopic anomalies as a peculiar evidence of vital effects on Δ47and δ13C fractionation. Although complicated by vital effects, the Δ47signature in Poritescorals still preserved a robust SST dependence, similar to those of recently published Δ47‐T calibrations. The observed Δ47offset relative to inorganic carbonate due to the vital effects is consistent, and relative variations in seasonal SST can be obtained. This study refines the Δ47thermometer in Poritescorals and strengthens its capacity to be used to reconstruct past SST. Sea surface temperature (SST) is a fundamental parameter of climate variation. Understanding how SST has changed in the past is important to inform climate predictions. One way to do this is by developing a reliable thermometer based on the clumped isotope composition (Δ47) of corals. However, the thermometer based on coral Δ47values may be complicated by biological factors that affect the Δ47values as the coral grows. We investigated two modern Poritescorals from the South China Sea by measuring their oxygen, carbon, and clumped isotope compositions. By comparing two samples from the same coral colony, we found that the impact of biological factors is significant, causing unusual patterns in the carbon and clumped isotopes. The biological factors also likely lead to differences in the coral Δ47values from two different colonies. To account for these potential intracolony and intercolony effects, we established a relationship between the Δ47values and SST based on the two corals. This relationship has the same temperature dependence as other Δ47thermometers established on synthetic carbonates in which no biological factors are involved and can be used as a thermometer to reconstruct seasonal SST. There is no evidence of intercolony or intracolony variations in mean Δ47values of Poritescorals on an annual timescaleCoral vital effects are found to cause relative disequilibrium of isotopic composition at an intracolony levelClumped isotopes analysis of Poritescorals is suitable for reconstructing relative changes in seasonal sea surface temperature