In Silico Identification and Molecular Mechanism of Novel Tyrosinase Inhibitory Peptides Derived from Nacre of Pinctada martensii.

Pearl and nacre powders have been valuable traditional Chinese medicines with whitening properties for thousands of years. We utilized a high-temperature and high-pressure method along with compound enzyme digestion to prepare the enzymatic hydrolysates of nacre powder of Pinctada martensii (NP-PMH). The peptides were identified using LC-MS/MS and screened through molecular docking and molecular dynamics simulations. The interactions between peptides and tyrosinase were elucidated through enzyme kinetics, circular dichroism spectropolarimetry, and isothermal titration calorimetry. Additionally, their inhibitory effects on B16F10 cells were explored. The results showed that a tyrosinase-inhibitory peptide (Ala-His-Tyr-Tyr-Asp, AHYYD) was identified, which inhibited tyrosinase with an IC50 value of 2.012 ± 0.088 mM. The results of the in vitro interactions showed that AHYYD exhibited a mixed-type inhibition of tyrosinase and also led to a more compact enzyme structure. The binding reactions of AHYYD with tyrosinase were spontaneous, leading to the formation of a new set of binding sites on the tyrosinase. The B16F10 cell-whitening assay revealed that AHYYD could reduce the melanin content of the cells by directly inhibiting the activity of intracellular tyrosinase. Additionally, it indirectly affects melanin production by acting as an antioxidant. These results suggest that AHYYD could be widely used as a tyrosinase inhibitor in whitening foods and pharmaceuticals.

In Vitro In Silico Screening Strategy and Mechanism of Novel Tyrosinase Inhibitory Peptides from Nacre of Hyriopsis cumingii.

For thousands of years, pearl and nacre powders have been important traditional Chinese medicines known for their skin whitening effects. To prepare the enzymatic hydrolysates of Hyriopsis cumingii nacre powder (NP-HCH), complex enzymatic hydrolysis by pineapple protease and of neutral protease was carried out after the powder was pre-treated with a high-temperature and high-pressure method. The peptides were identified using LC-MS/MS and picked out through molecular docking and molecular dynamics simulations. Subsequently, the tyrosinase inhibitory and antioxidant properties of novel tyrosinase inhibitory peptides were investigated in vitro. In addition, the enzymatic activity of tyrosinase in B16F10 cells as well as melanin content and antioxidant enzyme levels were also examined. The results showed that a tyosinase inhibitory peptide (Tyr-Pro-Asn-Pro-Tyr, YPNPY) with an efficient IC50 value of 0.545 ± 0.028 mM was identified. The in vitro interaction results showed that YPNPY is a reversible competitive inhibitor of tyrosinase, suggesting that it binds to the free enzyme. The B16F10 cell whitening test revealed that YPNPY can reduce the melanin content of B16F10 cells by directly inhibiting the activity of intracellular tyrosinase. Additionally, it indirectly affects melanin production by acting as an antioxidant. These results suggest that YPNPY could be widely used as a tyrosinase inhibitor in whitening foods and drugs.

Purification, Characterization, cDNA Cloning, and Bioinformatic Analysis of Zinc-Binding Protein from Magallana hongkongensis.

Oysters contain significant amounts of the zinc element, which may also be found in their proteins. In this study, a novel zinc-binding protein was purified from the mantle of the oyster Magallana hongkongensis using two kinds of gel filtration chromatograms. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that its molecular weight was approximately 36 kDa. The protein identified by the Q-Exactive mass spectrometer shared the highest sequence identity with carbonic anhydrase derived from Crassostrea gigas concerning amino acid sequence similarity. Based on homologous cloning and RACE PCR, the full-length cDNA of carbonic anhydrase from Magallana hongkongensis (designated as MhCA) was cloned and sequenced. The cDNA of MhCA encodes a 315-amino-acid protein with 89.74% homology to carbonic anhydrase derived from Crassostrea gigas. Molecular docking revealed that the two zinc ions primarily form coordination bonds with histidine residues in the MhCA protein. These results strongly suggest that MhCA is a novel zinc-binding protein in Magallana hongkongensis.

Factors affecting local alveolar bone thickness in unilateral maxillary canine-lateral incisor transposition.

INTRODUCTION: This study aimed to use 3-dimensional data to investigate the factors affecting local alveolar bone thickness in unilateral maxillary canine-lateral incisor transposition. METHODS: Pretreatment cone-beam computed tomography data of 34 patients with unilateral maxillary canine-lateral transposition were imported into Dolphin Imaging software (version 11.8; Dolphin Imaging and Management Solutions, Chatsworth, Calif) for 3-dimensional reconstruction. The age, gender, and type of transposition at the beginning of treatment were recorded. The thickness and height of the transposed canine, the labiopalatal and distomedial distance from the transposed canine to the apex of the lateral incisor, the inclination of the transposed lateral incisor, the apical height of the lateral incisor, and the alveolar bone thickness in the apical plane were measured. Multiple linear regression analyses were applied to investigate the factors affecting alveolar bone thickness in the apical plane of the transposed lateral incisor. Two sample t test were applied to assess the difference of alveolar bone thickness in patients of different ages. RESULTS: The 10 boys and 24 girls had a mean age of 12.26 ± 2.34 years. In all 34 participants, the apical alveolar bone thickness of transposed lateral incisors was significantly higher than that of the unaffected side (P <0.05). Based on multiple regression analyses, factors associated with a wider alveolar bone thickness were as follows: age (ß = -0.237; P = 0.008), the labiopalatal distance from the transposed canine to the apex of the lateral incisor (ß = 0.675; P <0.001), and the inclination of the transposed lateral incisor (ß = 0.048; P = 0.032). Patients aged <11 years had significantly thicker alveolar bone than that of patients aged >11 years (P <0.05). CONCLUSIONS: Patients with younger age, greater lateral incisor inclination, and greater labiopalatal distance between canine and lateral incisor had more alveolar bone thickness. Early treatment permits tooth movement within the thicker alveolar bone.

Recent advances in taste transduction mechanism, analysis methods and strategies employed to improve the taste of taste peptides.

Taste peptides are oligopeptides that enhance both aroma and taste of food, and they are classified into five categories based on their taste characteristics: salty, sour, umami, sweet, bitter, and kokumi peptide. Recently, taste peptides have attracted the attention of several fields of research in food science and commercial applications. However, research on taste receptors of taste peptides and their taste transduction mechanisms are not clearly understood and we present a comprehensive review about these topics here. This review covers the aspects of taste peptides perceived by their receptors in taste cells, the proposed transduction pathway, as well as structural features of taste peptides. Apart from traditional methods, molecular docking, peptidomic analysis, cell and animal models and taste bud biosensors can be used to explore the taste mechanism of taste peptides. Furthermore, synergistic effect, Maillard reaction, structural modifications and changing external environment are employed to improve the taste of taste peptides. Consequently, we discussed the current challenges and future trends in taste peptide research. Based on the summarized developments, taste peptides derived from food proteins potentially appear to be important taste substances. Their applications meet the principles of "safe, nutritious and sustainable" in food development.

Morphometric evaluation of alveolar bone after orthodontic treatment of multiple impacted teeth in the unilateral maxillary anterior region.

INTRODUCTION: This study aimed to investigate the height and thickness of alveolar bone by cone-beam computed tomography imaging after orthodontic treatment in the unilateral maxillary anterior region and speculate on reasons for the difference in alveolar bone morphology. METHODS: This study selected 11 patients (3 males and 8 females; mean age, 9.42 ± 1.45 years). Cone-beam computed tomography was performed for these 11 patients before and after treatment using Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif). Labial and palatal alveolar bone thickness (BT) at root apices and different levels along the roots and loss of alveolar bone height was measured for each impacted tooth and its contralateral homonymous tooth. RESULTS: After orthodontic therapy, all 3 impacted anterior teeth had different degrees of loss of labial alveolar bone height compared with the normal side (central incisor: -1.5 mm, P <0.005; lateral incisor: -1.06 mm, P <0.01; canine: -0.59 mm, P < 0.01). The lateral incisors also showed palatal alveolar bone height loss compared with the unaffected side (-0.8 mm, P <0.005). Alveolar BT at root apices of impacted canines was 1.14 mm thicker than the normal side (P <0.005). Central and lateral incisors were similar to the normal side. The thickness of the alveolar bone at 8, 10, and 12 mm of the impacted canine position was still larger than that on the healthy side, whereas the difference in average thickness between the healthy and affected side had been significantly reduced compared with pretreatment measurements. CONCLUSIONS: There is satisfactory retention of alveolar bone height in canines after orthodontic treatment; however, alveolar bone loss is slightly worse at central and lateral incisors. Retention of alveolar BT was normal for impacted anterior teeth, whereas excess apical alveolar BT at the canines, although still present, was substantially less significant than had been observed before treatment.

Theragra chalcogramma Hydrolysates, Rich in Gly-Leu-Pro-Ser-Tyr-Thr, Exerts Anti-Photoaging Potential via Targeting MAPK and NF-κB Pathways in SD Rats.

Previous studies have revealed that excessive exposure to UV irradiation is the main cause of skin photoaging and the signaling pathways of MAPK and NF-κB are involved in this progression. The present study aims to investigate the anti-photoaging effects of low molecular weight hydrolysates from Theragra chalcogramma (TCH) and to clarify the underlying mechanism. The degradation of mechanical barrier functions in photoaged skin was substantially ameliorated after TCH administration; meanwhile, TCH significantly elevated the antioxidant capacity and suppressed the over-production of inflammatory cytokine IL-1ß. Moreover, the histopathological deteriorations such as epidermal hyperplasia and dermal loss were significantly alleviated, along with the increase in procollagen type I content and decrease in MMP-1 activity (p < 0.05). Furthermore, TCH effectively blocked the MAPK and NF-κB signaling pathways through inhibition of the phosphorylation of p38, JNK, ERK, iκB, and p65 proteins. Collectively, these data indicate that TCH has potential as a novel ingredient for the development of anti-photoaging foods.

Novel Antioxidant Peptides from Crassostrea Hongkongensis Improve Photo-Oxidation in UV-Induced HaCaT Cells.

Enzymatic hydrolysates from Oysters (OAH) display multiple biological activities. Previously, a 3~5 KDa oyster ultrafiltration component (OUP) showed a high property of preventing skin oxidation. Subsequently, we identified specific peptides with such activity. OUP was fractionated stepwise by Sephadex-G25 and RP-HPLC, and active fractions were screened using UV-irradiated HaCaT cells. The most active fractions (OP5-3) were analyzed by LC-MS/MS and a total of 17 peptides were identified. Results from mass spectrometry showed that OP5-3 consisted of peptides with a molecular weight range of 841.51-1786.92 Da. Six of these peptides were synthesized for validating the activity of resisting skin oxidation in the same cell model. All six peptides showed varying degrees of antioxidant activity, while pretreatment of HaCaT cells with AIVAEVNEAAK alleviated UV cytotoxicity, inhibited metalloproteinase 1 (MMP-1) expression, and showed the highest activity to resist UV-induced skin photo-oxidation among these peptides. In addition, results from molecular docking analysis of MMP-1 with AIVAEVNEAAK showed that AIVAEVNEAAK suppresses its enzymatic activity by directly interacting with MMP-1 and thus exhibit anti-photoaging activity.

Investigation of the In Vivo, In Vitro, and In Silico Wound Healing Potential of Pinctada martensii Purified Peptides.

Previous studies found that both oral and topical administration of enzymatic digestion products < 3 K Da ultrafiltration fractions of Pinctada martensii mantle (PMPs) had pro-healing effects. Thus, we further purified them by Sephadex-G25 and screened them by cellular assays to obtain Pinctada martensii purified peptides (PMPPs). In this study, we explored the mechanism of PMPPs on wound healing by in vivo, in vitro, and in silico experiments. LC-MS/MS results showed that PMPPs consisted of 33 peptides with molecular weights ranging from 758.43 to 2014.04 Da, and the characteristic peptide was Leu-Asp. The results of cellular assays showed that PMPPs promoted the proliferation of human skin fibroblasts (HSF) (135%) and human immortalized keratinocyte (HaCaT) cells (125%) very significantly at 12.5 µg/mL. The in vivo results showed that PMPPs could achieve scarless healing by inhibiting the inflammatory response, accelerating the epithelialization process, and regulating collagen I/III ratio. The optimal peptide sequence FAFQAEIAQLMS of PMPPs was screened for key protein receptors in wound healing (EGFR1, FGFR1, and MMP-1) with the help of molecular docking technique, which also showed to be the key pro-healing active peptide sequence. Therefore, it may provide a therapeutic strategy with great potential for wound healing.

LC-MS and Transcriptome Analysis of Lipopeptide Biosynthesis by Bacillus velezensis CMT-6 Responding to Dissolved Oxygen.

Dissolved oxygen (DO) is an key factor for lipopeptide fermentation. To better understand the link between oxygen supply and lipopeptide productivity in Bacillus velezensis CMT-6, the mechanism of DO on the synthesis of antimicrobial lipopeptides by Bacillus velezensis CMT-6 was examined. The production of surfactin and iturin of CMT-6 was detected by liquid chromatography-mass spectrometer (LC-MS) under different DO conditions and transcriptome analysis was performed. At 100 and 200 rpm, the lipopeptides productions were 2753.62 mg/L and 3452.90 mg/L, respectively. There was no significant change in the yield of iturin but that of surfactin increased by 64.14%. Transcriptome analysis revealed that the enriched differential genes were concentrated in the GO term of oxidation-reduction process. The marked enrichment of the lipopeptides synthesis pathway, including microbial metabolism in diverse environments and carbon metabolism in the two-component system, were observed. More importantly, the expression levels of the four surfactin synthetase genes increased at higher DO, however, the iturin synthetase gene expression did not. Furthermore, modular surfactin synthetase was overexpressed (between 9- and 49-fold) at 200 rpm but not at 100 rpm, which is suggestive of efficient surfactin assembly resulting in surfactin overproduction. This study provides a theoretical basis for constructing engineering strains with high lipopeptide production to adapt to different DO.

The Potential Protective Effect and Possible Mechanism of Peptides from Oyster (Crassostrea hongkongensis) Hydrolysate on Triptolide-Induced Testis Injury in Male Mice.

Peptides from oyster hydrolysate (OPs) have a variety of biological activities. However, its protective effect and exact mechanism on testicular injury remain poorly understood. This study aimed to evaluate the protective effect of OPs on triptolide (TP)-induced testis damage and spermatogenesis dysfunction and investigate its underlying mechanism. In this work, the TP-induced testis injury model was created while OPs were gavaged in mice for 4 weeks. The results showed that OPs significantly improved the sperm count and motility of mice, and alleviated the seminiferous tubule injury. Further study showed that OPs decreased malonaldehyde (MDA) level and increased antioxidant enzyme (SOD and GPH-Px) activities, attenuating oxidative stress and thereby reducing the number of apoptotic cells in the testis. In addition, OPs improved the activities of enzymes (LDH, ALP and ACP) related to energy metabolism in the testis and restored the serum hormone level of mice to normal. Furthermore, OPs promoted the expression of Nrf2 protein, and then increased the expression of antioxidant enzyme regulatory protein (HO-1 and NQO1) in the testis. OPs inhibited JNK phosphorylation and Bcl-2/Bax-mediated apoptosis. In conclusion, OPs have a protective effect on testicular injury and spermatogenesis disorders caused by TP, suggesting the potential protection of OPs on male reproduction.

Collagen Peptides Derived from Sipunculus nudus Accelerate Wound Healing.

Marine collagen peptides have high potential in promoting skin wound healing. This study aimed to investigate wound healing activity of collagen peptides derived from Sipunculus nudus (SNCP). The effects of SNCP on promoting healing were studied through a whole cortex wound model in mice. Results showed that SNCP consisted of peptides with a molecular weight less than 5 kDa accounted for 81.95%, rich in Gly and Arg. SNCP possessed outstanding capacity to induce human umbilical vein endothelial cells (HUVEC), human immortalized keratinocytes (HaCaT) and human skin fibroblasts (HSF) cells proliferation and migration in vitro. In vivo, SNCP could markedly improve the healing rate and shorten the scab removal time, possessing a scar-free healing effect. Compared with the negative control group, the expression level of tumor necrosis factor-α, interleukin-1ß and transforming growth factor-ß1 (TGF-ß1) in the SNCP group was significantly down-regulated at 7 days post-wounding (p < 0.01). Moreover, the mRNA level of mothers against decapentaplegic homolog 7 (Smad7) in SNCP group was up-regulated (p < 0.01); in contrast, type II TGF-ß receptors, collagen I and α-smooth muscle actin were significantly down-regulated at 28 days (p < 0.01). These results indicate that SNCP possessed excellent activity of accelerating wound healing and inhibiting scar formation, and its mechanism was closely related to reducing inflammation, improving collagen deposition and recombination and blockade of the TGF-ß/Smads signal pathway. Therefore, SNCP may have promising clinical applications in skin wound repair and scar inhibition.

[Wound-healing acceleration of mice skin by Sipunculus nudus extract and its mechanism].

In order to explore the effect of Sipunculus nudus extract (SNE) on skin wound healing in mice and its mechanism, hemostasis effect of SNE was measured, the mouse skin wound model was established by full-thickness excision. The morphological changes of the wound were observed after the treatment with SNE and the healing rate was measured. The changes of wound histology were observed by hematoxylin eosin (HE) staining, Masson staining and transmission electron microscope (TEM). The expression of cell factors and related proteins was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Results showed that the SNE possessed hemostatic function. SNE could obviously improve the healing rate of wound in mouse and shorten time of scab removal compared with the none-treatment (NT) group ( P < 0.05).The pathological histology analysis results showed complete epidermal regeneration, with remarkable capillary and collagen fiber observed in the SNE group. The expression level of tumor necrosis factor-α (TNF -α), interleukin-1ß (IL-1ß) and transforming growth factor-ß1 (TGF-ß1) in SNE group was significantly lower than that of the NT group on 7 d ( P < 0.05). Moreover, compared with the NT group, the gene expressions level of Smad7 was significantly increased and the level of type II TGF-ß receptors (TGF-ßRII), collagen I (COL1A1) and α-smooth muscle actin (α-SMA) were significantly reduced in the SNE group on 28 d ( P < 0.05), but the difference was not statistically significant compared to Yunnanbaiyao group (PC group) ( P > 0.05). These results indicated that SNE possessed obvious activity of accelerating wound healing and inhibiting scar formation, and its mechanism was closely related to hemostatic function, regulation of inflammatory factors, collagen deposition, collagen fiber remodeling and intervening TGF-ß/Smads signal pathway. Therefore, SNE may have promising clinical applications in skin wound repair and scar inhibition.

Effect of Oral Administration of Active Peptides of Pinctada Martensii on the Repair of Skin Wounds.

Skin wound healing, especially chronic wound healing, is a common challenging clinical problem. It is urgent to broaden the sources of bioactive substances that can safely and efficiently promote skin wound healing. This study aimed to observe the effects of active peptides (APs) of the mantle of Pinctada martensii on wound healing. After physicochemical analysis of amino acids and mass spectrometry of APs, the effect of APs on promoting healing was studied through a whole cortex wound model on the back of mice for 18 consecutive days. The results showed that APs consisted of polypeptides with molecular weights in the range 302.17-2936.43 Da. The content of polypeptides containing 2-15 amino acids accounted for 73.87%, and the hydrophobic amino acids accounted for 56.51%. Results of in vitro experimentation showed that mice in APs-L group which were fed a low dose of APs (0.5 g/kg bw) had a shortened epithelialization time due to a shortening inflammatory period (p < 0.05). Mechanistically, this relied on its specific ability to promote the proliferation of CD31, FGF and EGF which accelerated the percentage of wound closure. Moreover, the APs-L group mice had enhanced collagen synthesis and increased type III collagen content in their wounds through a TGF-ß/Smad signaling pathway (p > 0.05). Consequently, scar formation was inhibited and wound healing efficiency was significantly improved. These results show that the APs of Pinctada martensii promote dermal wound healing in mice and have tremendous potential for development and utilization in skin wound healing.

Evaluation of Small Molecular Polypeptides from the Mantle of Pinctada Martensii on Promoting Skin Wound Healing in Mice.

Skin wound healing, especially chronic wound healing, is a common challenging clinical problem. It is urgent to broaden the sources of bioactive substances that can safely and efficiently promote skin wound healing. This study aimed to observe the effects of small molecular peptides (SMPs) of the mantle of Pinctada martensii on wound healing. After physicochemical analysis of amino acids and mass spectrometry of SMPs, the effect of SMPs on promoting healing was studied through a whole cortex wound model on the back of mice for 18 consecutive days. The results showed that SMPs consisted of polypeptides with a molecular weight of 302.17-2936.43 Da. The content of polypeptides containing 2-15 amino acids accounted for 73.87%, and the hydrophobic amino acids accounted for 56.51%. Results of in vitro experimentation showed that SMPs possess a procoagulant effect, but no antibacterial activity. Results of in vivo experiments indicated that SMPs inhibit inflammatory response by secretion of anti-inflammatory factor IL-10 during the inflammatory phase; during the proliferative phase, SMPs promote the proliferation of fibroblasts and keratinocytes. The secretion of transforming growth factor-ß1 and cyclin D1 accelerates the epithelialization and contraction of wounds. In the proliferative phase, SMPs effectively promote collagen deposition and partially inhibit superficial scar hyperplasia. These results show that SMPs promotes dermal wound healing in mice and have a tremendous potential for development and utilization in skin wound healing.

Pressure sensitive microparticle adhesion through biomimicry of the pollen-stigma interaction.

Many soft biomimetic synthetic adhesives, optimized to support macroscopic masses (∼kg), have been inspired by geckos, insects and other animals. Far less work has investigated bioinspired adhesion that is tuned to micro- and nano-scale sizes and forces. However, such adhesive forces are extremely important in the adhesion of micro- and nanoparticles to surfaces, relevant to a wide range of industrial and biological systems. Pollens, whose adhesion is critical to plant reproduction, are an evolutionary-optimized system for biomimicry to engineer tunable adhesion between particles and micro-patterned soft matter surfaces. In addition, the adhesion of pollen particles is relevant to topics as varied as pollinator ecology, transport of allergens, and atmospheric phenomena. We report the first observation of structurally-derived pressure-sensitive adhesion of a microparticle by using the sunflower pollen and stigma surfaces as a model. This strong, pressure-sensitive adhesion results from interlocking between the pollen's conical spines and the stigma's receptive papillae. Inspired by this behavior, we fabricated synthetic polymeric patterned surfaces that mimic the stigma surface's receptivity to pollen. These soft mimics allow the magnitude of the pressure-sensitive response to be tuned by adjusting the size and spacing of surface features. These results provide an important new insight for soft material adhesion based on bio-inspired principles, namely that ornamented microparticles and micro-patterned surfaces can be designed with complementarity that enable a tunable, pressure-sensitive adhesion on the microparticle size and length scale.

Copper-organic/octamolybdates: structures, bandgap sizes, and photocatalytic activities.

The structures, optical bandgap sizes, and photocatalytic activities are described for three copper-octamolybdate hybrid solids prepared using hydrothermal methods, [Cu(pda)]4[ß-Mo8O26] (I; pda = pyridazine), [Cu(en)2]2[γ-Mo8O26] (II; en = ethylenediamine), and [Cu(o-phen)2]2[α-Mo8O26] (III; o-phen = o-phenanthroline). The structure of I consists of a [Cu(pda)]4(4+) tetramer that bridges to neighboring [ß-Mo8O26](4-) octamolybdate clusters to form two-dimensional layers that stack along the a axis. The previously reported structures of II and III are constructed from [Cu2(en)4Mo8O26] and [Cu2(o-phen)4Mo8O26] clusters. The optical bandgap sizes were measured by UV-vis diffuse reflectance techniques to be ∼1.8 eV for I, ∼3.1 eV for II, and ∼3.0 eV for III. Electronic structure calculations show that the smaller bandgap size of I originates primarily from an electronic transition between the valence and conduction band edges comprised of filled 3d(10) orbitals on Cu(I) and empty 4d(0) orbitals on Mo(VI). Both II and III contain Cu(II) and exhibit larger bandgap sizes. Accordingly, aqueous suspensions of I exhibit visible-light photocatalytic activity for the production of oxygen at a rate of ∼90 µmol O2 g(-1) h(-1) (10 mg samples; radiant power density of ∼1 W/cm(2)) and a turnover frequency per calculated surface [Mo8O26](4-) cluster of ∼36 h(-1). Under combined ultraviolet and visible-light irradiation, I also exhibits photocatalytic activity for hydrogen production in 20% aqueous methanol of ∼316 µmol H2 g(-1) h(-1). By contrast, II decomposed during the photocatalysis measurements. The molecular [Cu2(o-phen)4(α-Mo8O26)] clusters of III dissolve into the aqueous methanol solution under ultraviolet irradiation and exhibit homogeneous photocatalytic rates for hydrogen production of up to ∼8670 µmol H2·g(-1) h(-1) and a turnover frequency of 17 h(-1). The clusters of III can be precipitated out by evaporation and redispersed into solution with no apparent decrease in photocatalytic activity. During the photocatalysis measurements, the dissolution of the clusters in III is found to occur with the reduction of Cu(II) to Cu(I), followed by subsequent detachment from the octamolybdate cluster. The lower turnover frequency, but higher photocatalytic rate, of III arises from the net contribution of all dissolved [Cu2(o-phen)4(α-Mo8O26)] clusters, compared to only the surface clusters for the heterogeneous photocatalysis of I.

Reversible Oxygen Redox Chemistry in High-Entropy P2-Type Manganese-Based Cathodes via Self-Regulating Mechanism.

The irreversible oxygen-redox reactions in the high-voltage region of sodium-layered cathode materials lead to poor capacity retention and structural instability during cycling, presenting a significant challenge in the development of high-energy-density sodium-ion batteries. This work introduces a high-entropy design for layered Na0.67Li0.1Co0.1Cu0.1Ni0.1Ti0.1Mn0.5O2 (Mn-HEO) cathode with a self-regulating mechanism to extend specific capacity and energy density. The oxygen redox reaction was activated during the initial charging process, accompanied by the self-regulation of active elements, enhancing the ionic bonds to form a vacancy wall near the TM vacancies and thus preventing the migration of transition metal elements. Systematic in situ/ex situ characterizations and theoretical calculations comprehensively support the understanding of the self-regulation mechanism of Mn-HEO. As a result, the Mn-HEO cathode exhibits a stable structure during cycling. It demonstrates almost zero strain within a wide voltage range of 2.0-4.5 V with a remarkable specific capacity (177 mAh g-1 at 0.05 C) and excellent long-term cycling stability (87.6% capacity retention after 200 cycles at 2 C). This work opens a new pathway for enhancing the stability of oxygen-redox chemistry and revealing a mechanism of crystal structure evolution for high-energy-density layered oxides.

Zincophile Zn2+ Conductor Regulation by Ultrathin Nano MoO3 Coating for Dendrite-Free Zn Anode.

Aqueous battery with nonflammable and instinctive safe properties has received great attention. However, issues related to Zn anode such as side reactions and rampant dendrite growth hinder the long-term circulation of AZMBs. Herein, an ultrathin(35 nm) MoO3 coating is deposited on the Zn anode by means of vacuum vapor deposition for the first time. Due to the peculiar layer structure of MoO3, insertion of Zn2+ in ZnxMoO3 acts as Zn2+ ion conductor, which regulates Zn2+ deposition in an ordered manner. Additionally, the MoO3 coating can also inhibit the hydrogen evolution and corrosion reactions at the interface. Therefore, both Zn//MoO3@Cu asymmetric battery and Zn symmetric battery cells manage to deliver satisfactory electrochemical performances. The symmetric cell assembled with MoO3@Zn shows a significant long cycle life of more than 1600 h at a current density of 2 mA cm-2. Meanwhile, the MoO3@Zn//Cu asymmetric cell exhibits an ultrahigh Zn deposition/stripping efficiency of 99.82% after a stable cycling of 650 h at 2 mA cm-2. This study proposes a concept of "zincophile Zn2+ conductor regulation" to dictate Zn electrodeposition and broadens novel design of vacuum evaporation for nano MoO3 modified Zn anodes.

Effect of baking on the structure and bioavailability of protein-binding zinc from oyster (Crassoetrea hongkongensis).

To compare the bioavailability of protein-binding zinc, we investigated the impact of baking on the structure of zinc-binding proteins. The results showed that zinc-binding proteins enriched in zinc with relative molecular weights distributed at 6 kDa and 3 kDa. Protein-binding zinc is predisposed to separate from proteins' interiors and converge on proteins' surface after being baked, and its structure tends to be crystalline. Especially -COO, -C-O, and -C-N played vital roles in the sites of zinc-binding proteins. However, baking did not affect protein-binding zinc's bioavailability which was superior to that of ZnSO4 and C12H22O14Zn. They were digested in the intestine, zinc-binding complexes that were easily transported and uptaken by Caco-2 cells, with transport and uptake rates as high as 62.15% and 15.85%. Consequently, baking can alter the conformation of zinc-binding proteins without any impact on protein-binding zinc's bioavailability which is superior to that of ZnSO4 and C12H22O14Zn.