Original Article Establishing a rapid animal model of osteoporosis with ovariectomy plus low calcium diet in rats

Abstract: The objective of this study was to rapidly develop osteoporotic model animals by combining ovariectomy with a low calcium diet in rats. Thirty, eight-week-old, female, Sprague-Dawley rats were either sham-operated (Sham) or ovariectomized (Ovx) and divided into three groups: Sham, Ovx, and Ovx + low calcium diet. Rats in the Sham and Ovx groups were fed a standard diet containing 1.1% w/w calcium while rats in the Ovx + low calcium diet group were fed a diet containing 0.1% w/w calcium. Serum osteocalcin and bone mineral density (BMD) of the lumbar vertebrae were measured 4 and 8 weeks after surgery. The rats were euthanized 12 weeks after surgery, and the BMD of the right femur and histomorphometry of the femoral neck were assessed at that time. The Ovx + low-calcium diet group had a significantly lower mean BMD of the lumbar vertebra and higher mean serum osteocalcin concentration than the Sham and Ovx groups. Twelve weeks after surgery, rats in the Ovx + low calcium diet group had a significantly lower BMD, smaller Tb.Th and Tb.N, and larger Tb.Sp of the right femoral neck than did rats in the Sham and Ovx groups. These data indicate that a low calcium diet can significantly accelerate bone loss in ovariectomized rats. Combining ovariectomy and a low calcium diet can save considerable time in the creation of osteoporotic model animals

Construction of a CQDs/Ag3PO4/BiPO4 Heterostructure Photocatalyst with Enhanced Photocatalytic Degradation of Rhodamine B under Simulated Solar Irradiation

A carbon quantum dot (CQDs)/Ag3PO4/BiPO4 heterostructure photocatalyst was constructed by a simple hydrothermal synthesis method. The as-prepared CQDs/Ag3PO4/BiPO4 photocatalyst has been characterized in detail by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible spectroscopy, and photoelectrochemical measurements. It is demonstrated that the CQDs/Ag3PO4/BiPO4 composite is constructed by assembling Ag3PO4 fine particles and CQDs on the surface of rice-like BiPO4 granules. The CQDs/Ag3PO4/BiPO4 heterostructure photocatalyst exhibits a higher photocatalytic activity for the degradation of the rhodamine B dye than that of Ag3PO4, BiPO4, and Ag3PO4/BiPO4. The synergistic effects of light absorption capacity, band edge position, separation, and utilization efficiency of photogenerated carriers play the key role for the enhanced photodegradation of the rhodamine B dye

Self-powered and light-adaptable stretchable electrochromic display

A stretchable electrochromic display with a self-powered feature is an attractive concept in addressing the demands of information visualization and interaction without an external power supply for next-generation wearable and portable electronics. Herein, a self-powered stretchable electrochromic display is proposed for the first time, with WO3 on the stretchable conductor as the electrochromic electrode integrated in parallel with the Zn/carbon electrodes and topped with a ZnCl2-based organohydrogel. This geometrically designed electrochromic device can be self-colored by the chemical potential gap between WO3/Zn electrodes. The self-bleaching process caused by the oxidation of the reduced WO3 electrode is facilitated by the leakage current between the WO3/carbon electrodes. In this constructed self-powered system, the electrochromic electrode shows reversible coloring/bleaching performance up to 50% strain and maintains favorable stability with power-free reversible electrochemical switching for 400 cycles. Optical contrast retention at 81% is maintained for 200 stretching/recovery cycles. The prepared device combined with a phosphorescent substrate is demonstrated as a light-adaptable stretchable display, where the “on/off” states of the display are shown in both bright and dark conditions without power consumption. This work provides broad application prospects for futuristic multifunctional stretchable and portable display electronics.Ministry of Education (MOE)This work was supported by funding from the Ministry of Education (MOE) Singapore, AcRF Tier 1, Project No. RG64/21 and National Natural Science Foundation of China (No. 51902250). The author W.W. thanks the support from the China Scholarship Council (Grant No 202006280507) and Basic Scientific Research of Xi’an Jiaotong University (Grant No. xzy022022028)

Single‐cell landscape analysis reveals systematic senescence in mammalian Down syndrome

Abstract Background Down syndrome (DS), which is characterized by various malfunctions, is the most common chromosomal disorder. As the DS population continues to grow and most of those with DS live beyond puberty, early‐onset health problems have become apparent. However, the cellular landscape and molecular alterations have not been thoroughly studied. Methods This study utilized single‐cell resolution techniques to examine DS in humans and mice, spanning seven distinct organs. A total of 71 934 mouse and 98 207 human cells were analyzed to uncover the molecular alterations occurring in different cell types and organs related to DS, specifically starting from the fetal stage. Additionally, SA‐β‐Gal staining, western blot, and histological study were employed to verify the alterations. Results In this study, we firstly established the transcriptomic profile of the mammalian DS, deciphering the cellular map and molecular mechanism. Our analysis indicated that DS cells across various types and organs experienced senescence stresses from as early as the fetal stage. This was marked by elevated SA‐β‐Gal activity, overexpression of cell cycle inhibitors, augmented inflammatory responses, and a loss of cellular identity. Furthermore, we found evidence of mitochondrial disturbance, an increase in ribosomal protein transcription, and heightened apoptosis in fetal DS cells. This investigation also unearthed a regulatory network driven by an HSA21 gene, which leads to genome‐wide expression changes. Conclusion The findings from this study offer significant insights into the molecular alterations that occur in DS, shedding light on the pathological processes underlying this disorder. These results can potentially guide future research and treatment development for DS