Research on the transition dynamics and linear (nonlinear) optical properties of mCherry

In this study, we explore the electron transition mechanism and optical properties of the popular red fluorescent protein mCherry. By examining the charge transfer spectrum and combining it with the mCherry hole-electron distribution, we identify that the charge transfer between the phenolate and imidazolinone loops significantly contributes to the absorption spectrum. Quantitative analysis of charge transfer shows that, overall, the electrons are transferred to the C16 atom in the middle of phenolate and the imidazolinone loops during absorption. We speculate that C16 may also absorb protons to enable the photoconversion of mCherry in the excited state, similar to the blinking mechanism of IrisFP. In addition, we further investigated the optical properties of mcherry in the external field by polarizability (hyperpolarizability), showing the anisotropy of the polarization, the first hyperpolarization and the second hyperpolarization by unit spherical representation. Our results suggest that significant polarization and second hyperpolarizability occur when the field direction and electron transfer direction are aligned. We also analyzed the polarizability and first hyperpolarizabilities for different external fields. The polarizability mutated when the external field satisfies the S_0,min-> S_1 transition. Finally, the study of the first hyperpolarizability shows that adjusting the appropriate field can lead to a linear photoelectric effect or second harmonic generation of mCherry. These studies have certain reference values for various red fluorescent protein correlation simulations and experiments because of the similarity of the red fluorescent protein

KU band full pol SAR

Taking over from the previous batch of Final Year Project students, whom had worked with the radar team from Temasek Lab (TL) @ NTU. The design of a full Polarimetric (POL) Synthetic Aperture Radar (SAR) system was fully developed by the previous team. However, the design has yet to be implemented into an actual SAR. Hence, this paper will include the details and the steps to implement the design into an actual SAR and the various testing and commissioning done to the system. In addition, several improvements were also made to the previous system such as the shifting of the 15GHz centre frequency of the system to the currently accepted 16GHz which was a requirement by IDA. Due to the need for the SAR system to be portable, the total power consumption of the system had to be satisfied in order for the system to last throughout the entire experimental trials. This paper will also introduce the method of selecting the correct type of voltage regulator boards and lithium polymer battery to sustain the entire system. This paper will also include a section on how actual experimental data was obtained from the SAR system via the conducting of an outdoor experimental trial and the various data processing method done via MATLAB for the combination of the various polarization images obtained from the trial to a single pseudo colour image. Further discussion on how to calibrate the individual polarized images prior to combination to obtain a clean final image will also be included.Bachelor of Engineerin

A red fluorescent protein laser based on microbubble cavity with high stability and ultra-low threshold

Biological lasers show considerable potential in the biomedical field. Fluorescent protein (FP) is a type of biomaterial with good luminescence efficiency that can be used as the luminescent gain medium in biological lasers. Red FPs (RFPs) show higher cell/tissue permeability, lower cell phototoxicity, and relatively less background fluorescence than FPs based on other colors. RFPs can be used in vivo for deep tissue imaging. mCherry is the most extensively used high-quality RFP because of its short maturation time and stable luminescence properties. In this study, we employ mCherry FPs with a whispering gallery mode microbubble cavity to fabricate a protein laser. The laser resonator achieves a maximum quality factor (Q factor) of 10^8, which is the highest Q factor among the currently available FP lasers. Moreover, this laser exhibits the lowest threshold of 169 fJ, which can effectively ensure that the pump light does not damage the luminescent material. The prepared laser shows excellent stability in a wide pH range with good photobleaching resistance and can be stored at 3 degree for more than a month. This laser can be used to perceive and observe life-related activities in deep tissues of organisms.Comment: 9 pages, 6 figure

Alkali-activated slag mortar molded by non-stirring molding: Compressive strength, hydration properties and microstructures

Alkali-activated slag (AAS) characterized by fast hardening and high early strength has potential application prospects in concrete canvas (CC), where a non-stirring molding method is required to prepare mortar. This paper provides a new method for the preparation of alkali-activated slag mortar (AASM) by non-stirring (sprinkling-molding), where mechanical properties, hydration properties, and microstructures were investigated. The results suggest that the compressive strength of the sprinkling-molding mortar was slightly lower than that of the conventional stirring-molding mortar, and the compressive strength with sodium silicate content of 15 % the slag mass at 28d can reach 44.5 MPa. The hydration products are dominated by amorphous C-A-S-H gels, with small amounts of hydrotalcite. There are differences in degree of hydration and microstructures of each layer in the sprinkling-molding mortar

3D Culture System for Liver Tissue Mimicking Hepatic Plates for Improvement of Human Hepatocyte (C3A) Function and Polarity

In vitro 3D hepatocyte culture constitutes a core aspect of liver tissue engineering. However, conventional 3D cultures are unable to maintain hepatocyte polarity, functional phenotype, or viability. Here, we employed microfluidic chip technology combined with natural alginate hydrogels to construct 3D liver tissues mimicking hepatic plates. We comprehensively evaluated cultured hepatocyte viability, function, and polarity. Transcriptome sequencing was used to analyze changes in hepatocyte polarity pathways. The data indicate that, as culture duration increases, the viability, function, polarity, mRNA expression, and ultrastructure of the hepatic plate mimetic 3D hepatocytes are enhanced. Furthermore, hepatic plate mimetic 3D cultures can promote changes in the bile secretion pathway via effector mechanisms associated with nuclear receptors, bile uptake, and efflux transporters. This study provides a scientific basis and strong evidence for the physiological structures of bionic livers prepared using 3D cultures. The systems and cultured liver tissues described here may serve as a better in vitro 3D culture platform and basic unit for varied applications, including drug development, hepatocyte polarity research, bioartificial liver bioreactor design, and tissue and organ construction for liver tissue engineering or cholestatic liver injury

S-allyl-l-cysteine attenuates bleomycin-induced pulmonary fibrosis and inflammation via AKT/NF-κB signaling pathway in mice

Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal lung disease characterized by inflammation, multifocal fibrotic lesions and excessive collagen deposition with limited therapies. As a major bioactive compound in garlic, S-allyl-l-cysteine (SAC) is a neuroprotective drug candidate to prevent cognitive decline, however, its anti-pulmonary fibrotic activity remains unknown. Here, we investigated whether SAC could attenuate bleomycin (BLM)-induced pulmonary fibrosis and inflammation in mice. Our results showed that SAC dose-dependently reduced the infiltration of inflammatory cells, pulmonary lesions and collagen deposition in BLM treated mice with downregulated mRNA expression levels of fibrotic genes including alpha smooth muscle actin (α-SMA), fibronectin, collagen I and collagen III as well as the protein level of α-SMA. In addition, SAC could also reduce the mRNA expression of inflammatory mediators such as TNF-α and iNOS. Furthermore, higher phosphorylation of AKT and NF-κB p65 in IPF patient samples and murine samples was verified by immunohistochemistry while SAC could decrease the phosphorylation level of AKT and NF-κB p65 in mice stimulated with BLM. These findings, for the first time, indicate that SAC might mediate AKT/NF-κB signaling pathway to inhibit BLM-induced pulmonary fibrosis and support the potential role of SAC as an anti-pulmonary fibrosis agent. Keywords: S-allyl-l-cysteine, Pulmonary fibrosis, Inflammation, AKT, NF-κ

Dehydrocostus Lactone Suppresses LPS-induced Acute Lung Injury and Macrophage Activation through NF-κB Signaling Pathway Mediated by p38 MAPK and Akt

Acute lung injury (ALI) is a severe clinical disease marked by dysregulated inflammation response and has a high rate of morbidity and mortality. Macrophages, which play diverse roles in the inflammatory response, are becoming therapeutic targets in ALI. In this study we investigated the effects of dehydrocostus lactone (DHL), a natural sesquiterpene, on macrophage activation and LPS-induced ALI. The macrophage cell line RAW264.7 and primary lung macrophages were incubated with DHL (0, 3, 5, 10 and 30 μmol/L) for 0.5 h and then challenged with LPS (100 ng/mL) for up to 8 hours. C57BL/6 mice were intratracheally injected with LPS (5 mg/kg) to induce acute lung injury (ALI) and then treated with a range of DHL doses intraperitoneally (5 to 20 mg/kg). The results showed that DHL inhibited LPS-induced production of proinflammatory mediators such as iNOS, NO, and cytokines including TNF-α, IL-6, IL-1β, and IL-12 p35 by suppressing the activity of NF-κB via p38 MAPK/MK2 and Akt signaling pathway in macrophages. The in vivo results revealed that DHL significantly attenuated LPS-induced pathological injury and reduced cytokines expression in the lung. NF-κB, p38 MAPK/MK2 and Akt signaling molecules were also involved in the anti-inflammatory effect. Collectively, our findings suggested that DHL is a promising agent for alleviating LPS-induced ALI