An Ultra-Low Modulus of Ductile TiZrHfTa Biomedical High-Entropy Alloys through Deformation Induced Martensitic Transformation/Twinning/Amorphization.

Biomedical alloys are paramount materials in biomedical applications, particularly in crafting biological artificial replacements. In traditional biomedical alloys, a significant challenge is simultaneously achieving an ultra-low Young's modulus, excellent biocompatibility, and acceptable ductility. A multi-component body-centered cubic (BCC) biomedical high-entropy alloy (Bio-HEA), which is composed of non-toxic elements, is noteworthy for its outstanding biocompatibility and compositional tuning capabilities. Nevertheless, the aforementioned challenges still remain. Here, a method to achieve a single phase with the lowest Young's modulus among the constituent phases by precisely tuning the stability of the BCC phase in the Bio-HEA, is proposed. The subtle tuning of the BCC phase stability also enables the induction of stress-induced martensite transformation with extremely low trigger stress. The transformation-induced plasticity and work hardening capacity are achieved via the stress-induced martensite transformation. Additionally, the hierarchical stress-induced martensite twin structure and crystalline-to-amorphous phase transformation provide robust toughening mechanisms in the Bio-HEA. The cytotoxicity test confirms that this Bio-HEA exhibits excellent biocompatibility without cytotoxicity. In conclusion, this study provides new insights into the development of biomedical alloys with a combination of ultra-low Young's modulus, excellent biocompatibility, and decent ductility.

Exposure of chlorothalonil and acetamiprid reduce the survival and cause multiple internal disturbances in Apis mellifera larvae reared in vitro.

Background: Chlorothalonil and acetamiprid are chemical pesticides commonly used in agricultural production and have been shown to have negative effects on bee's fitness. Despite many studies have revealed that honey bee (Apis mellifera L.) larvae are posting a high risk on exposure to pesticides, but the toxicology information of chlorothalonil and acetamiprid on bee larvae remain limited. Results: The no observed adverse effect concentration (NOAEC) of chlorothalonil and acetamiprid for honey bee larvae were 4 µg/mL and 2 µg/mL, respectively. Except for CarE, the enzymic activities of GST and P450 were not influenced by chlorothalonil at NOAEC, while chronic exposure to acetamiprid slightly increased the activities of the three tested enzymes at NOAEC. Further, the exposed larvae showed significantly higher expression of genes involved in a series of different toxicologically relevant process following, including caste development (Tor (GB44905), InR-2 (GB55425), Hr4 (GB47037), Ac3 (GB11637) and ILP-2 (GB10174)), immune system response (abaecin (GB18323), defensin-1 (GB19392), toll-X4 (GB50418)), and oxidative stress response (P450, GSH, GST, CarE). Conclusion: Our results suggest that the exposure to chlorothalonil and acetamiprid, even at concentrations below the NOAEC, showed potentially effects on bee larvae's fitness, and more important synergistic and behavioral effects that can affect larvae fitness should be explored in the further.