A Versatile Topology-Optimized Compliant Actuator for Soft Robotic Gripper and Walking Robot.

The remarkable interaction capabilities of soft robots within various environments have captured substantial attention from researchers. In recent years, bionics has provided a rich inspiration for the design of soft robots. Nevertheless, predicting the locomotion of soft actuators and determining material layouts solely based on intuition or experience remain a formidable challenge. Previous actuators predominantly targeted separate applications, leading to elevated costs and diminished interchangeability. The objective of this article is to extract the common requirements of diverse application domains and develop a versatile compliant actuator. A mathematical model of the compliant mechanism is proposed under the framework of topology optimization, resulting in an optimal distribution of both structure and material. Through comparison with empirical and semioptimal designs, the results show that the proposed versatile actuator has the advantages of both stiffness and flexibility. We propose an associative design strategy for soft grippers and walking robots. The soft gripper can perfectly complete adaptive grasping of objects with varying sizes, shapes, and masses. The successful in-water gripping experiment underscores the robust cross-medium operational capabilities of the soft gripper. Notably, our experimental results show that the walking robot can move quickly for 5 cycles in 8.25 s and can guarantee the control accuracy of continuous motion. Moreover, the robot swiftly switches walking directions within a mere 0.45 s. The optimization and design strategy presented in this article can furnish novel insights for shaping the next generation of soft robots.

Adenine-adenine, adenine-cytosine and cytosine-cytosine intrastrand crosslinks induced by a photoactivatable Pt(IV) anticancer prodrug.

Four trinucleotides 5'-ATA-3' (I), 5'-ATC-3' (II), 5'-CTA-3' (III) and 5'-CTC-3' (IV) were introduced to interact with a diazido-based photoactivatable anticancer prodrug trans,trans,trans-[PtIV(N3)2(OH)2(py)2] (py = pyridine; 1) upon light irradiation. Using electrospray ionization mass spectrometry (ESI-MS), we aimed to investigate the possibility of 1,3-intrastrand crosslinks at adenine and/or cytosine in the trinucleotides via the bi-functional trans-[PtII(py)2]2+ species generated by photodecomposition of complex 1. The primary mass spectrometry results showed that although mono- and di-platinated trinucleotides bound by mono-functional trans-[PtII(N3)(py)2]+ species were the major platinated adducts, comparable amounts of bifunctional trans-[PtII(py)2]2+-bound trinucleotides were also observed. Further tandem mass spectrometry of the trans-[PtII(py)2]2+-bound trinucleotides showed the formation of 1,3-crosslinks between adenine-adenine, adenine-cytosine and cytosine-cytosine bases in the trinucleotides. The formation of such unique structures is not only distinct from the action modes of cisplatin with DNA but also an important complement to the acknowledged 1,3-GNG intrastrand crosslink by trans-Pt species, which may support the promising and distinct anticancer activities of such photoactivatable diazido Pt(IV) anticancer prodrugs and deserve further studies.

Reaction of human telomeric unit TTAGGG and a photoactivatable Pt(IV) anticancer prodrug.

The interaction of a photoactivatable diazidodihydroxido Pt(IV) prodrug, trans,trans,trans-[Pt(N3)2(OH)2(py)2] (py = pyridine; 1), with a hexamer straight human telomeric DNA unit sequence (5'-T1T2A3G4G5G6-3', I) upon light irradiation was investigated by electrospray ionization mass spectroscopy (ESI-MS). In the primary mass spectrum, two major mono-platinated I adducts with the bound Pt moieties, trans-[PtII(N3)(py)2]+ (1') and trans-[PtII(py)2]2+ (1''), respectively, were detected. It is rare to observe such high abundance and nearly equal intensity platinated DNA adducts formed by these two PtII species because 1' is usually the only major reduced Pt(II) species produced by the photodecomposition of complex 1 in the presence of DNA while 1'' was rarely detected as the major reduced PtII species reported previously. Subsequent tandem mass spectrometric analysis by collision-induced dissociation (CID) showed that in the former adduct {I + 1'}2+, G6 and A3 were the platination sites. While in the latter adduct {I + 1''}2+, a potential intrastrand crosslink was speculated after G4 and G6 sites were identified. Additionally, other minor platinated adducts like di-platinated I adduct by 1' with platination sites at G4 and G6 and mono-platinated I adducts containing base oxidation were also detected by mass spectrometry. Due to the rich guanines and their sensitivity to oxidation, the oxidation induced by 1 most probably occurred at guanine. The oxidation adducts were proposed as 8-hydroxyl guanine, spiroiminodihydantoin (Sp), 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG), 5-guanidinohydantoin (Gh), and/or dehydroguanidinohydantoin (DGh) referring to previous reports. The obtained results provide useful chemical information about the photoreaction between photoactivatable Pt(IV) anticancer prodrugs and human telomeric DNA. Such special damages of Pt(IV) prodrugs on human telomeric DNA implicate its active role in the mechanism of Pt(IV) prodrugs and further support the unique sequence-dependent photointeraction profile of complex 1 reacting with DNA.

Newly reconstructed Arctic surface air temperatures for 1979-2021 with deep learning method.

A precise Arctic surface air temperature (SAT) dataset, that is regularly updated, has more complete spatial and temporal coverage, and is based on instrumental observations, is critically important for timely monitoring and improving understanding of the rapid change in the Arctic climate. In this study, a new monthly gridded Arctic SAT dataset dated back to 1979 was reconstructed with a deep learning method by combining surface air temperatures from multiple data sources. The source data include the observations from land station of GHCN (Global Historical Climatology Network), ICOADS (International Comprehensive Ocean-Atmosphere Data Set) over the oceans, drifting ice station of Russian NP (North Pole), and buoys of IABP (International Arctic Buoy Programme). The last two are crucial for improving the representation of the in-situ observed temperatures within the Arctic. The newly reconstructed dataset includes monthly Arctic SAT beginning in 1979 and daily Arctic SAT beginning in 2011. This dataset would represent a new improvement in developing observational temperature datasets and can be used for a variety of applications.

Molecular responses to salinity stress in Salix matsudana (Koidz) females and males.

Sexual dimorphism has commonly been found in many species. The phenotypes of Salix matsudana females and males are different under salinity stress. An F1 population was selected to compare the differences between males and females. As a result, males showed stronger roots and heavier dry weights than females. The unique molecular mechanisms of males and females under salinity stress were further analyzed based on the root transcriptome of males and females. Both males and females up-regulated systemic acquired resistance genes, such as ADH and oxygenase-related genes, to resist salt. Moreover, many other abiotic stress response genes were up-regulated in males to adjust to salinity stress, while females showed more down-regulation of nitrogen metabolism-related genes to decrease the harm from salinity stress. The research on salinity tolerance in Salix matsudana males and females would help to further understand sexual dimorphism under selection pressure and provide benefits to the ecological environment.

Differentiated oxidation modes of guanine between CpG and 5mCpG by a photoactivatable Pt(IV) anticancer prodrug.

CpG and its cytosine-methylated counterpart (5mCpG) are a unique reversible pair of sequences in regulating the expression of genes epigenetically. As DNA is the potential target of Pt-based anticancer metallodrugs, herein, we comparatively investigate the interactions of 5'-CpG and 5'-5mCpG with a photoactivatable anticancer Pt(IV) prodrug, trans,trans,trans-[PtIV(N3)2(OH)2(py)2] (1; py = pyridine), to explore the effects of methylation on the platination and ROS-induced oxidation of the CpG motif. Mono-platinated dinucleotides were demonstrated by ESI-MS to be the main products for both 5'-CpG and 5'-5mCpG with the bound Pt moiety as [PtII(N3)(py)2] generated by the photodecomposition of complex 1 under irradiation with blue light, accompanied by the formation of less abundant di-platinated adducts. G-N7 and C-N3/5mC-N3 were shown to be the major and minor platination sites, respectively, with G-N1 as the third and weakest platination site, in particular, in di-platinated products. Moreover, platinated dinucleotides associated with guanine and/or cytosine oxidation were also observed. Apart from 8-oxo-guanine (oxG) and N-formylamidoiminohydantoin (RedSp) reported previously, novel oxidation adducts 5-guanidinohydantoin (Gh) derived from guanine and 1-carbamoyl-4,5-dihydroxy-2-oxoimidazolidine (ImidCyt) derived from cytosine in CpG, and diimino imidazole (DIz) and 2,5-diaminoimidazol-4-one (imidazolone, Iz) derived from guanine and Imid5mCyt derived from 5mC in 5mCpG were proposed according to MS information. These results showed that methylation exerted little effects on the platination modes of CpG, but triggered distinct oxidation pathways of CpG, perhaps causing discriminated DNA damage to CpG-rich genes. This work provides novel insights into the role of the anticancer photoactivatable Pt(IV) prodrug through damaging the epigenetically modified DNA sequences.

Soil properties and microbial communities of spring maize filed in response to tillage with straw incorporation and nitrogen fertilization in northeast China.

Soil enzymes and microorganisms are both important to maintaining good soil quality and are also sensitive to changes in agricultural management. The individual effects of tillage, straw incorporation and nitrogen (N) fertilization on soil enzymes and microflora have been widely acknowledged, but their interactive effect remains largely unknown. In a 5-year in-situ field study, effects of rotary (RTS) and plow tillage (PTS) practices with straw incorporation combined with three N fertilization levels (0 kg N ha-1, CK; 187 kg N ha-1, MN; 337 kg N ha-1, HN) on soil enzyme activities and microbial communities were assessed. Our results showed that the activities of ß-glucosidase (ßG), N-acetylglucosaminidase (NAG) and acid phosphatase (APH) were improved in RTS+MN. The bacterial and fungal abundances in RTS+MN and RTS+HN were 1.27-27.51 times higher than those in other treatment groups. However, the bacterial and fungal alpha diversities were enhanced in PTS+MN and PTS+CK compared with other treatments, respectively. Proteobacteria and Basidiomycota were the predominant phylum for the respective bacterial and fungal communities. Moreover, significant interactive effects were found in the fungal community composition, but only minor impacts were observed on the bacterial community composition. Soil water content and penetration resistance contributed more to the soil enzyme activity and microbial community than other soil properties investigated, whereas there was a significant positive correlation between ßG and APH activities and microbial abundance. These findings can provide new insights into tillage with straw incorporation and N fertilization on maize cultivation in northeast China.

Heavy metals in agricultural soil in China: A systematic review and meta-analysis.

Research about farmland pollution by heavy metals/metalloids in China has drawn growing attention. However, there was rare information on spatiotemporal evolution and pollution levels of heavy metals in the major grain-producing areas. We extracted and examined data from 276 publications between 2010 and 2021 covering five major grain-producing regions in China from 2010 to 2021. Spatiotemporal evolution characteristics of main heavy metals/metalloids was obtained by meta-analysis. In addition, subgroup analyses were carried out to study preliminary correlations related to accumulation of the pollutants. Cadmium (Cd) was found to be the most prevailing pollutant in the regions in terms of both spatial distribution and temporal accumulation. The Huang-Huai-Hai Plain was the most severely polluted. Accumulation of Cd, mercury (Hg) and copper (Cu) increased from 2010 to 2015 when compared with the 1990 background data. Further, the levels of five key heavy metals (Cd, Cu, Hg, lead [Pb] and zinc [Zn]) showed increasing trends from 2016 to 2021 in all five regions. Soil pH and mean annual precipitation had variable influences on heavy metal accumulation. Alkaline soil and areas with less rainfall faced higher pollution levels. Farmlands cropped with mixed species showed smaller effect sizes of heavy metals than those with single upland crop, suggesting that mixed farmland use patterns could alleviate the levels of heavy metals in soil. Of various soil remediation efforts, farmland projects only held a small market share. The findings are important to support the research of risk assessment, regulatory development, pollution prevention, fund allocation and remediation actions.

Experimental investigations on scale-dependent dispersivity in three-dimensional heterogeneous porous media.

The relationship between the scale-dependent dispersivity and heterogeneous sedimentary structures is investigated through conducting non-reactive tracer experiments in a three-dimensional heterogeneous sand tank. The heterogeneous porous media consists of three sedimentary facies of silty, fine, and medium sands collected from the west of the Songnen Plain, China. Moreover, several corresponding individual facies soil columns were constructed for comparison. A conservative tracer was continuously injected from an upstream source. The effective parameters were estimated by inverse modeling of a one-dimensional transport model. The results show that the scale dependence of the estimated dispersivities was discovered in the individual facies column (with relatively weaker effect) and the heterogeneous porous media (with more significant effect). With increasing transport distances, the dispersivities of the individual facies tend to reach an asymptotic value, while those of the heterogeneous media increase continuously. Furthermore, the results show that a power function can describe the relationship between effective dispersivities and transport distances. The exponent of the function is greater than one for the heterogeneous media, but less than one for the individual facies. The results also indicate that the dispersion plume is macroscopically dominated by the distribution of facies. The heterogeneity of hydraulic conductivity causes the variations of flow velocity, which further enhances the scale dependence of dispersivities. The tracer experiment in heterogeneous media provides the fundamental insight into the understanding of contaminant transport processes.