The RNA ligase RNA terminal phosphate cyclase B regulates mRNA alternative splicing and is required for mouse oocyte development and maintenance.

Recent large-scale mRNA sequencing has shown that introns are retained in 5-10% of mRNA, and these events are named intron retention (IR). IR has been recognized as a key mechanism in the regulation of gene expression. However, the role of this mechanism in female reproduction in mammals remains unclear. RNA terminal phosphate cyclase B (RTCB) is a RNA ligase; we found that RTCB conditional knockout mice have premature ovarian failure and that RTCB plays a crucial role in follicular development. RTCB regulated the splicing of transcripts related to DNA methylation and DNA damage repair. In addition, it regulated the resumption of oocyte meiosis by affecting CDK1 activation. Moreover, the loss of RTCB suppressed zygotic genome activation (ZGA) and decreased translation at the global level. In addition, Rtcb deletion resulted in the accumulation of maternal mRNAs containing unspliced introns and in a decline in the overall level of transcripts. As a result, the Rtcb-/- females were sterile. Our study highlights the important role of RTCB-regulated noncanonical alternative splicing in female reproduction.

Nuclear poly(A) binding protein 1 (PABPN1) mediates zygotic genome activation-dependent maternal mRNA clearance during mouse early embryonic development.

An embryo starts its life with maternal mRNA clearance, which is crucial for embryonic development. The elimination of maternal transcripts occurs by the joint action of two pathways: the maternally encoded mRNA decay pathway (M-decay) and the zygotic genome activation (ZGA)-dependent pathway (Z-decay). However, zygotic factors triggering maternal mRNA decay in early mammalian embryos remain largely unknown. In this study, we identified the zygotically encoded nuclear poly(A) binding protein 1 (PABPN1) as a factor required for maternal mRNA turnover, with a previously undescribed cytoplasmic function. Cytoplasmic PABPN1 docks on 3'-uridylated transcripts, downstream of terminal uridylyl transferases TUT4 and TUT7, and recruits 3'-5' exoribonuclease DIS3L2 to its targets, facilitating maternal mRNA decay. Pabpn1-knockout in mice resulted in preimplantation stage mortality due to early developmental arrest at the morula stage. Maternal mRNAs to be eliminated via the Z-decay pathway failed to be removed from Pabpn1-depleted embryos. Furthermore, PABPN1-mediated Z-decay is essential for major ZGA and regulates the expression of cell fate-determining factors in mouse preimplantation embryos. This study revealed an unforeseen cytoplasmic function of PABPN1 coupled with early embryonic development, characterized the presence of a zygotic destabilizer of maternal mRNA, and elucidated the Z-decay process mechanisms, which potentially contribute to human fertility.

USP16-mediated histone H2A lysine-119 deubiquitination during oocyte maturation is a prerequisite for zygotic genome activation.

Maternal-to-zygotic transition (MZT) is the first and key step in the control of animal development and intimately related to changes in chromatin structure and histone modifications. H2AK119ub1, an important epigenetic modification in regulating chromatin configuration and function, is primarily catalyzed by PRC1 and contributes to resistance to transcriptional reprogramming in mouse embryos. In this study, the genome-wide dynamic distribution of H2AK119ub1 during MZT in mice was investigated using chromosome immunoprecipitation and sequencing. The results indicated that H2AK119ub1 accumulated in fully grown oocytes and was enriched at the TSSs of maternal genes, but was promptly declined after meiotic resumption at genome-wide including the TSSs of early zygotic genes, by a previously unidentified mechanism. Genetic evidences indicated that ubiquitin-specific peptidase 16 (USP16) is the major deubiquitinase for H2AK119ub1 in mouse oocytes. Conditional knockout of Usp16 in oocytes did not impair their survival, growth, or meiotic maturation. However, oocytes lacking USP16 have defects when undergoing zygotic genome activation or gaining developmental competence after fertilization, potentially associated with high levels of maternal H2AK119ub1 deposition on the zygotic genomes. Taken together, H2AK119ub1 level is declined during oocyte maturation by an USP16-dependent mechanism, which ensures zygotic genome reprogramming and transcriptional activation of essential early zygotic genes.

NAT10-mediated N4-acetylcytidine modification is required for meiosis entry and progression in male germ cells.

Post-transcriptional RNA modifications critically regulate various biological processes. N4-acetylcytidine (ac4C) is an epi-transcriptome, which is highly conserved in all species. However, the in vivo physiological functions and regulatory mechanisms of ac4C remain poorly understood, particularly in mammals. In this study, we demonstrate that the only known ac4C writer, N-acetyltransferase 10 (NAT10), plays an essential role in male reproduction. We identified the occurrence of ac4C in the mRNAs of mouse tissues and showed that ac4C undergoes dynamic changes during spermatogenesis. Germ cell-specific ablation of Nat10 severely inhibits meiotic entry and leads to defects in homologous chromosome synapsis, meiotic recombination and repair of DNA double-strand breaks during meiosis. Transcriptomic profiling revealed dysregulation of functional genes in meiotic prophase I after Nat10 deletion. These findings highlight the crucial physiological functions of ac4C modifications in male spermatogenesis and expand our understanding of its role in the regulation of specific physiological processes in vivo.

Role of CxxC-finger protein 1 in establishing mouse oocyte epigenetic landscapes.

During oogenesis, oocytes gain competence and subsequently undergo meiotic maturation and prepare for embryonic development; trimethylated histone H3 on lysine-4 (H3K4me3) mediates a wide range of nuclear events during these processes. Oocyte-specific knockout of CxxC-finger protein 1 (CXXC1, also known as CFP1) impairs H3K4me3 accumulation and causes changes in chromatin configurations. This study investigated the changes in genomic H3K4me3 landscapes in oocytes with Cxxc1 knockout and the effects on other epigenetic factors such as the DNA methylation, H3K27me3, H2AK119ub1 and H3K36me3. H3K4me3 is overall decreased after knocking out Cxxc1, including both the promoter region and the gene body. CXXC1 and MLL2, which is another histone H3 methyltransferase, have nonoverlapping roles in mediating H3K4 trimethylation during oogenesis. Cxxc1 deletion caused a decrease in DNA methylation levels and affected H3K27me3 and H2AK119ub1 distributions, particularly at regions with high DNA methylation levels. The changes in epigenetic networks implicated by Cxxc1 deletion were correlated with the transcriptional changes in genes in the corresponding genomic regions. This study elucidates the epigenetic changes underlying the phenotypes and molecular defects in oocytes with deleted Cxxc1 and highlights the role of CXXC1 in orchestrating multiple factors that are involved in establishing the appropriate epigenetic states of maternal genome.

Covalent Grafting of Dielectric Films on Cu(111) Surface via Electrochemical Reduction of Aryl Diazonium Salts.

Covalent grafting of dielectric films containing polyhedral oligomeric silsesquioxane (POSS) on the surface of Cu(111) is performed by a one-step electrochemical reduction of diazonium salts. This method is efficient and economic and performs in a proton-polar solvent of deionized water and tetrahydrofuran (THF), where the monomer employs an octavinylsilsesquioxane (OVS) containing a POSS core. The eight vinyl bonds contained in OVS are used to participate in aryl radical-initiated polymerization reactions to form films. The formed film is dense and covers the copper surface completely and uniformly. The thickness of the film can be controlled by adjusting the reaction time. The components of the films are mainly polynitrophenyl (PNP) or polyaminophenyl (PAP) as well as poly(octavinylsilsesquioxane) (POVS), and the POVS content could be adjusted by the applied voltage. The introduction of POSS prevents the copper surface from being oxidized and often gives the film good properties such as good dielectric properties, mechanical properties, and thermal properties. In addition, the presence of Cu-O-C and Cu-C bonds between the film and copper interface is confirmed at different film thicknesses by X-ray photoelectron spectroscopy (XPS), which allowed the construction of covalent bonds between metal and nonmetal, further enhancing the bonding between the film and copper. Organic films prepared by electrochemical reduction of diazonium salts using OVS as a monomer will have potential significance for the future development of the electronics industry.

PABPN1L mediates cytoplasmic mRNA decay as a placeholder during the maternal-to-zygotic transition.

Maternal mRNA degradation is a critical event of the maternal-to-zygotic transition (MZT) that determines the developmental potential of early embryos. Nuclear Poly(A)-binding proteins (PABPNs) are extensively involved in mRNA post-transcriptional regulation, but their function in the MZT has not been investigated. In this study, we find that the maternally expressed PABPN1-like (PABPN1L), rather than its ubiquitously expressed homolog PABPN1, acts as an mRNA-binding adapter of the mammalian MZT licensing factor BTG4, which mediates maternal mRNA clearance. Female Pabpn1l null mice produce morphologically normal oocytes but are infertile owing to early developmental arrest of the resultant embryos at the 1- to 2-cell stage. Deletion of Pabpn1l impairs the deadenylation and degradation of a subset of BTG4-targeted maternal mRNAs during the MZT. In addition to recruiting BTG4 to the mRNA 3'-poly(A) tails, PABPN1L is also required for BTG4 protein accumulation in maturing oocytes by protecting BTG4 from SCF-ßTrCP1 E3 ubiquitin ligase-mediated polyubiquitination and degradation. This study highlights a noncanonical cytoplasmic function of nuclear poly(A)-binding protein in mRNA turnover, as well as its physiological importance during the MZT.

A conversion-type lithium artificial synapse with dispersed nano-silica fabricated by UV-curing method.

The rapid growth of information puts forward new requirements for computer including denser memory capacity and faster response beyond the traditional von Neumann architecture. One promising strategy is to employ novel computing devices such as artificial synapses (AS). Here, an Au/LPSE-SiO2/Si AS (LPSE-SiO2AS) with a simple sandwich structure was fabricated by UV curing. LPSE-SiO2AS emulated synaptic plasticity including excitatory postsynaptic current, paired-pulse facilitation, and spike-dependent plasticity. It also simulated the memory strengthening and forgetting analogue to biological system. The realization of synaptic plasticity is due to the homogeneously dispersed nano-silica in LPSE, which acts as lithium ions trapping center and conducts a reversible electrochemical conversion reaction with Li ions with pulse stimulation. These results indicate the potential for LPSE-SiO2AS in future large-scale integrated neuromorphic networks.

Application of electrodeposited Cu-metal nanoflake structures as 3D current collector in lithium-metal batteries.

Since uncontrolled lithium (Li) dendrite growth and dendrite-induced dead Li severely limit the development of Li metal batteries, 3D Cu current collectors can effectively alleviate these problems during Li plating/stripping. Herein, one-step galvanostatic electrodeposition method is employed to fabricate a new current collector on Cu foam decorated with large-scale and uniform 3D porous Cu-based nanoflake (NF) structures (abbreviated as 3D Cu NF@Cu foam). This 3D structure with large internal surface areas not only generates lithophilic surface copper oxides and hydroxides as charge centers and nucleation sites for Li insertion/extraction, but also endows abundant space with interlinked NFs for buffering the cell volume expansion and increasing battery performance. As a result, Li-deposited 3D Cu NF@Cu foam current collector can realize stable cycling over 455 cycles with an average Coulombic efficiency of 98.8% at a current density of 1.0 mA cm-2, as well as a prolonged lifespan of >380 cycles in symmetrical cell without short-circuit, which are superior to those of blank Cu foam current collector. This work realizes Li metal anode stabilization by constructing 3D porous Cu NFs current collectors, which can advance the development of Li metal anode for battery industries.

ZAR1 and ZAR2 are required for oocyte meiotic maturation by regulating the maternal transcriptome and mRNA translational activation.

Zar1 was one of the earliest mammalian maternal-effect genes to be identified. Embryos derived from Zar1-null female mice are blocked before zygotic genome activation; however, the underlying mechanism remains unclear. By knocking out Zar1 and its homolog Zar2 in mice, we revealed a novel function of these genes in oocyte meiotic maturation. Zar1/2-deleted oocytes displayed delayed meiotic resumption and polar body-1 emission and a higher incidence of abnormal meiotic spindle formation and chromosome aneuploidy. The grown oocytes of Zar1/2-null mice contained decreased levels of many maternal mRNAs and displayed a reduced level of protein synthesis. Key maturation-associated changes failed to occur in the Zar1/2-null oocytes, including the translational activation of maternal mRNAs encoding the cell-cycle proteins cyclin B1 and WEE2, as well as maternal-to-zygotic transition (MZT) licensing factor BTG4. Consequently, maternal mRNA decay was impaired and MZT was abolished. ZAR1/2 bound mRNAs to regulate the translational activity of their 3'-UTRs and interacted with other oocyte proteins, including mRNA-stabilizing protein MSY2 and cytoplasmic lattice components. These results countered the traditional view that ZAR1 only functions after fertilization and highlight a previously unrecognized role of ZAR1/2 in regulating the maternal transcriptome and translational activation in maturing oocytes.

Genome-wide survey of the bHLH super gene family in Brassica napus.

BACKGROUND: The basic helix-loop-helix (bHLH) gene family is one of the largest transcription factor families in plants and is functionally characterized in diverse species. However, less is known about its functions in the economically important allopolyploid oil crop, Brassica napus. RESULTS: We identified 602 potential bHLHs in the B. napus genome (BnabHLHs) and categorized them into 35 subfamilies, including seven newly separated subfamilies, based on phylogeny, protein structure, and exon-intron organization analysis. The intron insertion patterns of this gene family were analyzed and a total of eight types were identified in the bHLH regions of BnabHLHs. Chromosome distribution and synteny analyses revealed that hybridization between Brassica rapa and Brassica oleracea was the main expansion mechanism for BnabHLHs. Expression analyses showed that BnabHLHs were widely in different plant tissues and formed seven main patterns, suggesting they may participate in various aspects of B. napus development. Furthermore, when roots were treated with five different hormones (IAA, auxin; GA3, gibberellin; 6-BA, cytokinin; ABA, abscisic acid and ACC, ethylene), the expression profiles of BnabHLHs changed significantly, with many showing increased expression. The induction of five candidate BnabHLHs was confirmed following the five hormone treatments via qRT-PCR. Up to 246 BnabHLHs from nine subfamilies were predicted to have potential roles relating to root development through the joint analysis of their expression profiles and homolog function. CONCLUSION: The 602 BnabHLHs identified from B. napus were classified into 35 subfamilies, and those members from the same subfamily generally had similar sequence motifs. Overall, we found that BnabHLHs may be widely involved in root development in B. napus. Moreover, this study provides important insights into the potential functions of the BnabHLHs super gene family and thus will be useful in future gene function research.

Correction to: Two different therapies for the middle turbinate during endoscopic sinus surgery for chronic rhinosinusitis.

In the original publication of the article, Fig. 1a was missing and caption of Fig. 1a was published as caption of Fig. 1b. The correct Fig. 1 and captions are provided below.

Two different therapies for the middle turbinate during endoscopic sinus surgery for chronic rhinosinusitis.

BACKGROUND: The population of patients with chronic rhinosinusitis (CRS) has greatly increased. When medical treatment fails, endoscopic sinus surgery (ESS) is considered. In the present study, the value of two different therapies for the middle turbinate to optimize surgical outcomes was observed. Our objective was to determine a better management approach for the middle turbinate to effectively preserve the middle turbinate mucosa and function and avoid complications following ESS, such as nasal adhesions on the operative side. METHODS: Thirty patients [group A; treated prior to 2015 (primary surgery)] undergoing resection of the middle turbinate bone during complete ESS for CRS and 30 patients [group B; treated after 2015 (later surgery)] undergoing middle turbinate preservation and multiapproach therapy during complete ESS for CRS were observed. Nasal cavities were compared using perioperative sinus endoscopy (POSE) and Lund-Kennedy (LKES) scores preoperatively and at 15 days, 2 months and 1 year after ESS. RESULTS: Preoperatively, the POSE (8.83 ± 3.81 vs 9.15 ± 3.85, p = 0.45, for groups A and B, respectively) and LKES (4.23 ± 0.74 vs 4.13 ± 0.70, p = 0.34) scores were similar between groups. In group A, anterior adhesions were reported on six sides of the middle turbinate, severe adhesions were observed on two sides, mild adhesions were observed on one side, and adhesions occurred on two sides during follow-up. After retreatment, adhesions were still observed on two sides at 1 year. In group B, only mild anterior adhesions were observed on two sides. There was no difference between group A and group B at 15 days, and the POSE (4.31 ± 1.19 vs 4.07 ± 1.42, p = 0.11, for groups A and B, respectively) and LKES (3.35 ± 0.82 vs 3.33 ± 0.90, p = 0.91) scores were similar between groups. There was no significant difference in LKES (0.22 ± 0.49 vs 0.10 ± 0.35, p = 0.15) scores at 1 year between the two groups. There was a significant difference in the nasal cavities between group A and group B at 2 months and 1 year, where group B showed a better endoscopic appearance than group A at 2 months and 1 year (with POSE scores of 3.48 ± 0.83 vs 2.43 ± 1.38 (p = 0.00) and LKES scores of 1.35 ± 0.86 vs 1.15 ± 0.90 (p = 0.02) at 2 months for groups A and B, respectively, and POSE scores of 1.00 ± 0.96 vs 0.62 ± 0.87 (p = 0.001) at 1 year for groups A and B, respectively). CONCLUSIONS: Our results show that middle turbinate preservation and combined therapy was a better ESS method for CRS. Multiapproach middle conchoplasty, which is predominately a submucoperiosteal surgery, can preserve more of the mucosa and functions of the middle turbinate. Unlike the single-approach middle conchoplasty described in previous research, multiapproach middle conchoplasty is achieved by combining a three-step surgical procedure ("surgery, packing and removal") with "cocktail-style" postoperative packing and removal.

Genome-wide survey and expression analyses of the GRAS gene family in Brassica napus reveals their roles in root development and stress response.

MAIN CONCLUSION: Genome-wide identification, classification, expression analyses, and functional characterization of GRAS genes in oil crop, Brassica napus, indicate their importance in root development and stress response. GRAS proteins are a plant-specific transcription factor gene family involved in tissues development and stress response. We classified 87 putative GRAS genes in the Brassica napus genome (BnGRASs) into 13 subfamilies by phylogenetic analysis. The C-terminal GRAS domains of Brassica napus (B. napus) proteins were less conserved among subfamilies, but were conserved within each subfamily. A series of analyses revealed that 89.7% of the BnGRASs did not have intron insertions, and 24 specific-motifs were found at the N-terminal. A highly conserved microRNA 171 (miRNA171) target was observed specifically in the HAM subfamily across land plants. A total of 868 pairs of interaction proteins were predicted, the primary of which were transcription factors involved in transcriptional regulation and signal transduction. Integrated comparative analysis of GRAS genes across 26 species of algae, mosses, ferns, gymnosperms, and angiosperms revealed that this gene family originated in early mosses and was classified into 19 subfamilies, 14 of which may have originated prior to bryophyte evolution. RNA-Seq analysis demonstrated that most BnGRASs were widely expressed in different tissues/organs at different stages in B. napus, and 24 BnGRASs were highly/specifically expressed in roots. Results from a qRT-PCR analysis suggested that two BnGRASs belonging to SCR and LISCL subfamilies potentially have important roles in the stress response of roots.

Ultra-compact high-sensitivity plasmonic sensor based on Fano resonance with symmetry breaking ring cavity.

Miniaturizing optical devices with desired functionality is a key prerequisite for nanoscale photonic circuits. Based on Fano resonance, an on-chip high-sensitivity sensor, composed of two waveguides coupling with a symmetry breaking ring resonator, is theoretically and numerically investigated. The established theoretical model agrees well with the finite-difference time-domain simulations, which reveals the physics of Fano resonance. Differing with the coupled cavities, the Fano resonance originates from the interference between symmetry-mode and asymmetry-mode in a single symmetry-broken cavity. The spectral responses and sensing performances of the plasmonic structure rely on the degree of asymmetry of cavity. In particular, the plasmonic sensor can detect the refractive index changes as small as 10-5, and the figure of merit (FOM) of symmetry-breaking cavity structure is 17 times larger than that of symmetrical cavity system. Additionally, the sensitivity to temperature of ethanol analyte achieves 0.701 nm/○C. Compared with the coupled cavities, the on-chip high-sensitivity sensor using a single cavity is more compact, which paves the way toward highly integrated photonic devices.

Highly Efficient Utilization of Nano-Fe(0) Embedded in Mesoporous Carbon for Activation of Peroxydisulfate.

Nanoscale zerovalent iron (nZVI) particles have received much attention in environmental science and technology due to their unique electronic and chemical properties. However, the aggregation and oxidation of nZVI brings much difficulty in practical application of environmental remediation. In this study, we reported a composite nano-Fe(0)/mesoporous carbon by a chelation-assisted coassembly and carbothermal reduction strategy. Nano-Fe(0) particles with surface iron oxide (Fe2O3·FeO) were wrapped with graphitic layers which were uniformly dispersed in mesoporous carbon frameworks. The unique structure made the nano-Fe(0) particles stable in air for more than 20 days. It was used as a peroxydisulfate (PDS) activator for the oxidation treatment of 2,4,6-trichlorophenol (TCP). The TOF value of MCFe for TCP degradation is nearly 3 times higher than those of FeSO4 and Fe2O3·FeO and nearly 2 times than that of commercial nZVI. The reactive oxygen species (ROS) including •SO4-, HO•, and •O2-, 1O2 are efficiently generated by PDS activation with MCFe. The PDS activation process by nano-Fe(0) particles was intrinsically induced by the ferrous ions (Fe(II)) continuously generated at the solid/aqueous interface. Namely, the nano-Fe(0) particles were highly efficiently utilized in sulfate radical-based advanced oxidation processes (SR-AOP). The porous structure also assists the absorption and transfer of TCP during the degradation process.

Evolutionary and Comparative Expression Analyses of TCP Transcription Factor Gene Family in Land Plants.

The plant-specific Teosinte-branched 1/Cycloidea/Proliferating (TCP) transcription factor genes are involved in plants' development, hormonal pathways, and stress response but their evolutionary history is uncertain. The genome-wide analysis performed here for 47 plant species revealed 535 TCP candidates in terrestrial plants and none in aquatic plants, and that TCP family genes originated early in the history of land plants. Phylogenetic analysis divided the candidate genes into Classes I and II, and Class II was further divided into CYCLOIDEA (CYC) and CINCINNATA (CIN) clades; CYC is more recent and originated from CIN in angiosperms. Protein architecture, intron pattern, and sequence characteristics were conserved in each class or clade supporting this classification. The two classes significantly expanded through whole-genome duplication during evolution. Expression analysis revealed the conserved expression of TCP genes from lower to higher plants. The expression patterns of Class I and CIN genes in different stages of the same tissue revealed their function in plant development and their opposite effects in the same biological process. Interaction network analysis showed that TCP proteins tend to form protein complexes, and their interaction networks were conserved during evolution. These results contribute to further functional studies on TCP family genes.

Global Analysis of WOX Transcription Factor Gene Family in Brassica napus Reveals Their Stress- and Hormone-Responsive Patterns.

The plant-specific WUSCHEL-related homeobox (WOX) transcription factor gene family is important for plant growth and development but little studied in oil crops. We identified and characterized 58 putative WOX genes in Brassica napus (BnWOXs), which were divided into three major clades and nine subclades based on the gene structure and conserved motifs. Collinearity analysis revealed that most BnWOXs were the products of allopolyploidization and segmental duplication events. Gene structure analysis indicated that introns/exons and protein motifs were conserved in each subclade and RNA sequencing revealed that BnWOXs had narrow expression profiles in major tissues and/or organs across different developmental stages. The expression pattern of each clade was highly conserved and similar to that of the sister and orthologous pairs from Brassica rapa and Brassica oleracea. Quantitative real-time polymerase chain reaction showed that members of the WOX4 subclade were induced in seedling roots by abiotic and hormone stresses, indicating their contribution to root development and abiotic stress responses. 463 proteins were predicted to interact with BnWOXs, including peptides regulating stem cell homeostasis in meristems. This study provides insights into the evolution and expression of the WOX gene family in B. napus and will be useful in future gene function research.

Electrodeposition of High Density Silver Nanosheets with Controllable Morphologies Served as Effective and Reproducible SERS Substrates.

Silver nanosheets with a nanogap smaller than 10 nm and high reproducibility were constructed through simple and environmentally friendly electrodeposition method on copper plate. The sizes of the nanogaps can be varied from around 7 to 150 nm by adjusting the deposition time and current density. The nanosheets with different nanogaps exhibited varied surface-enhanced Raman scattering (SERS) properties due to electromagnetic mechanism (EM). The optimized high density silver nanosheets with a nanogap smaller than 10 nm showed effective SERS ability with an enhanced factor as high as 2.0 × 10(5). Furthermore, the formation mechanism of the nanosheets during the electrodeposition process has been investigated by discussing the influence of boric acid and current density. This method has proved to be applicable on different metal substrates, which exhibits the potential to be widely used in different fields.

Wetting transition of the caterpillar-like superhydrophobic Cu/Ni-Co hierarchical structure by heat treatment.

Caterpillar-like hierarchical structured Cu/Ni-Co coatings were fabricated by a simple two-step method of combined electroless and electrodeposition. Both contact angles and sliding angles were measured to investigate the hydrophobicity after stearic acid modification. The results revealed the contact angle was as high as 165.5°(superhydrophobic), while the sliding angle was only 3.5°, which makes it very promising as self-cleaning material. Wetting transition from slippery hydrophobicity to sticky hydrophobicity happened upon heat treatment. The scanning electron microscopy (SEM) analysis disclosed the morphology change of the hierarchical structure during the heat treatment leading to the wetting state transition. Different models of wetting states were raised and calculated to provide further confirmation of the transition. The contact angle remained larger than 156° when the pH value ranged from 1 to 14 and the heat-treatment temperature was from 100 to 250 °C. Such hierarchical micronanostructure and its special hydrophobicity are expected to have practical application in industry.