During S phase, replicated DNA must be assembled into nucleosomes using both newly synthesized and parental histones in a process that is tightly coupled to DNA replication. This DNA ...replication-coupled process is regulated by multitude of histone chaperones as well as by histone-modifying enzymes. In recent years novel insights into nucleosome assembly of new H3–H4 tetramers have been gained through studies on the classical histone chaperone CAF-1 and the identification of novel factors involved in this process. Moreover, in vitro reconstitution of chromatin replication has shed light on nucleosome assembly of parental H3–H4, a process that remains elusive. Finally, recent studies have revealed that the replication-coupled nucleosome assembly is important for the determination and maintenance of cell fate in multicellular organisms.
Replication-coupled nucleosome assembly is the process by which newly synthesized DNA is assembled into nucleosomes immediately following DNA replication, and uses both parental and newly synthesized histones.
An in vitro reconstituted DNA replication system using a chromatin template identifies minimal factors involved in parental histone transfer.
New roles for well-known proteins, including the single-stranded DNA-binding complex RPA, have been established in both DNA replication-coupled and DNA replication-independent nucleosome assembly.
Transcription factors and chromatin remodelers cooperate to re-establish chromatin architecture at gene regulatory elements and gene bodies after the passing of the replication fork.
The histone chaperone CAF-1 is involved in the maintenance of cell fate and differentiation.
Bulk-heterojunction organic photovoltaic devices with nonfullerene acceptors (NFAs) exhibit efficient hole transfer with small interfacial energy offset, which results in power conversion ...efficiencies above 17% in single junction devices using the high-performance NFA of Y6. However, the underlying mechanism responsible for the hole transfer channel in the polymer/Y6 blends remains poorly understood. Herein, we report that the hole transfer channel of photocharge generation is mediated by an intra-moiety excited state in a blend of donor polymer PM6 and NFA Y6 using broadband transient absorption (TA) spectroscopy. By comparing the TA data recorded from the solution and film Y6 samples, we identify the ultrafast formation of an intra-moiety excimer state together with the conversion from the primary local excitation on a time scale of ∼0.2 ps in the Y6 film. The intra-moiety excimer state acts as the intermediate for the hole transfer channel, which dissociates into free polarons on a time scale of ∼15 ps in the PM6/Y6 blend at room temperature. The intra-moiety intermediate state, arising from the intermolecular coupling in Y6 domains, is markedly different from the interfacial charge transfer state, which is commonly accepted as the intermediate state for the electron transfer channel. These findings suggest that manipulating the interplay between intra-moiety and interfacial excited species can provide a promising route for further improving device performance.
Multiline tunneling construction in soft soil significantly impedes risk control and environmental protection. Current research has investigated on the effect of single-line shield excavation on ...surrounding environments and tunneling for parallel-crossing or perpendicular down-crossing underground structures. However, minimal attention has been given to soil disturbances induced by multiline tunneling and complex overlapped interaction mechanics for adjacent structures, such as existing above-crossing and down-crossing subway tunnels. Few studies focus on oblique crossing construction and setting rules for the operation parameters of shield machines. Based on the Shanghai Railway transportation project and in situ monitoring data, the deformation analyses of existing subway tunnels induced by an earth pressure balance (EPB) shield during the process of above-overlapped and down-overlapped crossing tunnels with oblique angles are presented. The deformation analyses employ the three-dimensional finite element (3D FE) numerical simulation method, and the simplified analytical method. The analysis results from the theoretical methods are consistent with the monitoring data. The setting rules of multiline propulsion main parameters, including the earth pressure for cutting open, and the synchronized grouting, are also established. This study may provide a theoretical basis for the development of properly overlapped crossing schemes and geotechnical protective measures during multiline tunneling construction in soft soil.
The pathogenesis and clinical features of diabetic cardiomyopathy have been well-studied in the past decade, but effective approaches to prevent and treat this disease are limited. Diabetic ...cardiomyopathy occurs as a result of the dysregulated glucose and lipid metabolism associated with diabetes mellitus, which leads to increased oxidative stress and the activation of multiple inflammatory pathways that mediate cellular and extracellular injury, pathological cardiac remodelling, and diastolic and systolic dysfunction. Preclinical studies in animal models of diabetes have identified multiple intracellular pathways involved in the pathogenesis of diabetic cardiomyopathy and potential cardioprotective strategies to prevent and treat the disease, including antifibrotic agents, anti-inflammatory agents and antioxidants. Some of these interventions have been tested in clinical trials and have shown favourable initial results. In this Review, we discuss the mechanisms underlying the development of diabetic cardiomyopathy and heart failure in type 1 and type 2 diabetes mellitus, and we summarize the evidence from preclinical and clinical studies that might provide guidance for the development of targeted strategies. We also highlight some of the novel pharmacological therapeutic strategies for the treatment and prevention of diabetic cardiomyopathy.
•A two steps analytical approach is presented to analyze the interaction mechanics for excavation–soil–tunnels.•3D numerical analysis is conducted and the simplified analytical method can overcome ...complex simulation.•Galerkin’s method is used to convert the differential equation into finite element equation.•The excavation unloading effects of bottom and surrounding walls can be fully considered.•The parametric analyses are presented to investigate the effects of excavation-induced unloading on tunnels.
A major challenge in the design and construction of soil excavation and foundation pit engineering in urban areas is the protection of adjacent underground structures, such as existing tunnels. Excavation-induced soil unloading can adversely affect and even damage the tunnels in the vicinity. A simplified analytical approach is presented to analyze the deformation response for adjacent tunnels due to excavation-induced soil unloading in excavation engineering. Firstly, the green soil unloading stress due to adjacent excavation is estimated at the existing tunnel location. Secondly, the deformation response of the tunnel subjected to green soil unloading stress is calculated by the Galerkin’s method, which can be used to obtain the finite element equation converted from the differential equation. The accuracy of the proposed method is verified by comparisons with 3D finite element numerical simulation, centrifuge model tests provide by Kusakabe et al. (1985) and measured data in situ. Finally, the parametric analysis for deformation influence factors of the existing tunnel, including the tunnel buried depth, the distance from the excavation site, the soil geo-characters and the outer diameter of the tunnel, is presented to demonstrate the performance of the proposed method. This proposed method may provide certain basis to make protective measures of existing tunnels influenced by excavation engineering and enables a quick estimate of the deformation behavior of excavation-induced adjacent tunnels, resulting in savings in time and costs.
The potential benefit of social participation (SP) to one's mental health has been widely acknowledged. Nevertheless, the specific type and amount of SP that is associated with improved depressive ...symptoms in middle- and old-aged Chinese awaits further investigation. This study aimed to understand the patterns of depression and SP by comparing urban vs rural China, and according to which, measure the associations between changes in SP and that in depressive symptoms. A total of 10,988 community residents aged 45 years and above were selected from wave 1 (2011), wave 2 (2013), and wave 4 (2015) of the China Health and Retirement Longitudinal Study (CHARLS), a nationally representative survey. The fixed-effects analysis was used to explore the association between the changes in diversity, frequency, and type of SP and the changes in depressive symptoms. The results indicated that rural respondents suffered from a significantly higher risk of depression and took less SP than their urban counterparts. Transitioning from no SP to 1 or more types of SP or to a once a week or higher frequency was associated with a decline in depressive symptoms. For urban respondents, playing mah-jong or cards and joining sports or social clubs predicted a decline in depressive symptoms. For rural residents, interacting with friends regularly was associated with fewer depressive symptoms. In conclusion, more diverse and higher frequency of SP was associated with better mental health, while the social significance of SP varied across different types of SP and between rural and urban areas.
•Correlations between depression and dimensions of SP were measured in China's context.•We used fixed-effects analysis and highlighted rural-urban disparity.•Diverse and frequent SP associated with lower depressive symptoms in older adults.•Effects of different types of SP varied between rural and urban senior residents.•Playing mahjong associated with lower depressive symptoms in urban older adults.
A ratiometric oxygen sensor based on a platinum octaethylporphyrin (PtOEP)–coumarin 6 (C6)/poly (styrene-trifluoroethyl methacrylate) (poly (St-TFEMA)) film was developed for automatic dissolved ...oxygen (DO) detection. The oxygen-sensing film according to the dynamic quenching mechanism was prepared by embedding platinum octaethylporphyrin (PtOEP) and coumarin 6 (C6) in poly (styrene-trifluoroethyl methacrylate) (poly (St-TFEMA)). The optical parameter (OP) was defined as the ratio of the oxygen-insensitive fluorescence from C6 to the oxygen-sensitive phosphorescence from PtOEP. A calibration equation expressing the correlation between the OP values and DO content described by a linear function was obtained. A program based on the Labview software was developed for monitoring the real-time DO content automatically. The influence of the excitation intensity and fluctuation on the OP values and the direct luminescence signal (integration areas) was compared, verifying the strong anti-interference ability of the sensor. The detection limit of the sensor was determined to be 0.10 (1) mg/L. The switching response time and recovery time of the sensor were 0.4 and 1.3 s, respectively. Finally, the oxygen sensor was applied to the investigation of the kinetic process of the DO content variation, which revealed an exponential relationship with time.
The efficient separation of xenon (Xe) and krypton (Kr) is one of the industrially important processes. While adsorptive separation of these two species is considered to be an energy efficient ...process, developing highly selective adsorbent remains challenging. Herein, a rigid squarate-based metal–organic framework (MOF), having a perfect pore size (4.1 Å × 4.3 Å) comparable with the kinetic diameter of Xe (4.047 Å) as well as pore surface decorated with very polar hydroxyl groups, is able to effectively discriminate Xe atoms, affording a record-high Xe/Kr selectivity. An exceptionally high Xe uptake capacity of 58.4 cm3/cm3 and selectivity of 60.6 at low pressure (0.2 bar) are achieved at ambient temperature. The MOF exhibits the highest Xe Henry coefficient (192.1 mmol/g/bar) and Xe/Kr Henry selectivity (54.1) among all state-of-the-art adsorbents reported so far. Direct breakthrough experiments further confirm the excellent separation performance. The density functional theory calculations reveal that the strong interaction between Xe and the framework is a result of the synergy between optimal pore size and polar porosity.
An optical temperature sensor based on the upconversion luminescence of Tm3+ has been developed. Under a 980nm diode laser excitation, the fluorescence intensity ratio (FIR) between 700 ...(Tm3+:3F2,3→3H6) and 800nm (Tm3+:3H4→3H6) upconversion emissions from Tm3+/Yb3+ codoped oxyfluoride glass ceramic was studied as a function of temperature in the range of 293–703K. The 3F2,3 and 3H4 states of Tm3+ are verified to be thermally coupled levels. By using FIR technique, the sensitivity for detecting temperature variations achieved here is better than previous reported rare earth ions fluorescence based temperature sensors. With the advantages of intense upconversion luminescence and absolutely separated 700 and 800nm emission bands, the Tm3+/Yb3+ codoped oxyfluoride glass ceramic is a very promising candidate for accurate optical temperature sensors with much higher sensitivity and resolution.
Berberine, a major pharmacological component of the Chinese herb Coptis chinensis, which was originally used to treat bacterial diarrhea, has recently been demonstrated to be clinically effective in ...alleviating type 2 diabetes. In this study, we revealed that berberine effectively prevented the development of obesity and insulin resistance in high-fat diet (HFD)-fed rats, which showed decreased food intake. Increases in the levels of serum lipopolysaccharide-binding protein, monocyte chemoattractant protein-1, and leptin and decrease in the serum level of adiponectin corrected for body fat in HFD-fed rats were also significantly retarded by the co-administration of berberine at 100 mg/kg body weight. Bar-coded pyrosequencing of the V3 region of 16S rRNA genes revealed a significant reduction in the gut microbiota diversity of berberine-treated rats. UniFrac principal coordinates analysis revealed a marked shift of the gut microbiota structure in berberine-treated rats away from that of the controls. Redundancy analysis identified 268 berberine-responding operational taxonomic units (OTUs), most of which were essentially eliminated, whereas a few putative short-chain fatty acid (SCFA)-producing bacteria, including Blautia and Allobaculum, were selectively enriched, along with elevations of fecal SCFA concentrations. Partial least square regression models based on these 268 OTUs were established (Q(2)>0.6) for predicting the adiposity index, body weight, leptin and adiponectin corrected for body fat, indicating that these discrete phylotypes might have a close association with the host metabolic phenotypes. Taken together, our findings suggest that the prevention of obesity and insulin resistance by berberine in HFD-fed rats is at least partially mediated by structural modulation of the gut microbiota, which may help to alleviate inflammation by reducing the exogenous antigen load in the host and elevating SCFA levels in the intestine.
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