Tissue-specific Gene Expression Changes Are Associated with Aging in Mice

Aging is a complex process that can be characterized by functional and cognitive decline in an individual. Aging can be assessed based on the functional capacity of vital organs and their intricate interactions with one another. Thus, the nature of aging can be described by focusing on a specific organ and an individual itself. However, to fully understand the complexity of aging,one must investigate not only a single tissue or biological process but also its complex interplay and interdependencies with other biological processes. Here, using RNA-seq, we monitored changes in the transcriptome during aging in four tissues(including brain, blood, skin and liver) in mice at9 months, 15 months, and 24 months, with a final evaluation at the very old age of 30 months.We identified several genes and processes that were differentially regulated during aging in both tissue-dependent and tissue-independent manners. Most importantly, we found that the electron transport chain(ETC) of mitochondria was similarly affected at the transcriptome level in the four tissues during the aging process. We also identified the liver as the tissue showing the largest variety of differentially expressed genes(DEGs) over time. Lcn2(Lipocalin-2) was found to be similarly regulated among all tissues, and its effect on longevity and survival was validated using its orthologue in Caenorhabditis elegans. Our study demonstrated that the molecular processes of aging are relatively subtle in their progress, and the aging process of every tissue depends on the tissue’s specialized function and environment. Hence, individual gene or process alone cannot be described as the key of aging in the whole organism.

Performance Analysis of Silicon and Blue Phosphorene/MoS2 Hetero-Structure Based SPR Sensor

Surface plasmon resonance (SPR) sensor based on the blue phosphorene/MoS2 hetero-structure is presented to enhance the performance parameters, i.e., sensitivity, detection accuracy, and quality fhctor.The blue phosphorene/MoS2 hetero-structure works as an interacting layer with the analyte for the enhancement of the sensitivity of the sensor. It is observed that the sensitivity of blue phosphorene/MoS2 based sensor (i.e., structure-Ⅱ) is improved by 5.75%, from the conventional sensor (i.e., structure-Ⅲ). Further, an additional silicon nanolayer is introduced between the metal layer and blue phosphorene/MoS2 hetero-structure. The sensitivity of the proposed blue phosphorene/MoS2 hetero-structure with a silicon layer SPR sensor, i.e., structure-Ⅰ, is enhanced by 44.76% from structure-Ⅱ and 55.75% from structure-Ⅲ due to an enhancement in the evanescent field near the metal-analyte interface. Finally, it is observed that at the optimum thickness of silicon between the gold layer and blue phosphorene/MoS2, performance parameters of the sensor are enhanced.