Calcium-chelating peptides from rabbit bone collagen:characterization,identification and mechanism elucidation

This study aimed to characterize and identify calcium-chelating peptides from rabbit bone collagen and explore the underlying chelating mechanism.Collagen peptides and calcium were extracted from rabbit bone by instant ejection steam explosion(ICSE)combined with enzymatic hydrolysis,followed by chelation reaction to prepare rabbit bone peptide-calcium chelate(RBCP-Ca).The chelating sites were further analyzed by liquid chromatography-tandem mass(LC-MS/MS)spectrometry while the chelating mechanism and binding modes were investigated.The structural characterization revealed that RBCP successfully chelated with calcium ions.Furthermore,LC-MS/MS analysis indicated that the binding sites included both acidic amino acids(Asp and Glu)and basic amino acids(Lys and Arg),Interestingly,three binding modes,namely Inter-Linking,Loop-Linking and Mono-Linking were for the first time found,while Inter-Linking mode accounted for the highest proportion(75.1%),suggesting that chelation of calcium ions frequently occurred between two peptides.Overall,this study provides a theoretical basis for the elucidation of chelation mechanism of calcium-chelating peptides.

基于分子束外延技术可控制备Bi原子团簇的研究

本研究基于分子束外延(MBE)技术在Si(111)衬底表面成功制备金属Bi原子团簇.首先,分别在100℃、125℃、150℃、175℃、200℃的生长温度下,制备了大小均一、密度不同的Bi原子团簇.实验结果表明,可以通过改变生长温度来精细控制Bi原子团簇的密度,当温度升高100℃,密度从1.05×10^(11)cm^(-2)降低至2.5×10^(7)cm^(-2),实现对团簇密度4个数量级的可控调节,并且发现Bi原子团簇密度对生长温度的依赖性符合经典成核理论.其次,分别在10 s、15 s、20 s的沉积时长下,制备了密度相同、尺寸各异的Bi原子团簇.实验结果表明,可以通过改变沉积时长来精细控制Bi原子团簇的尺寸:当沉积时长增加10 s,高度和直径分别从8.5 nm和65 nm增大到13.7 nm和100 nm,实现对团簇尺寸在10 nm高度、80 nm直径范围的可控调节,并且发现Bi原子团簇尺寸对沉积时长的依赖性符合晶体生长动力学.与分子束外延制备传统的Ⅲ族(Al,Ga,In)原子团簇做对比,这些结果可以为制备Ⅴ族原子团簇提供实验参考和指导,从而促进纳米级含Bi材料的制备.

Anti-skin aging effects and bioavailability of collagen tripeptide and elastin peptide formulations in young and middle-aged women

Background:Collagen peptides(CP),including tripeptides and elastin peptides(EP),are known for their in vitro and in vivo anti-skin aging effects.Despite positive results in animal models,the combination effects of CP and EP and the bioavailability of CP in human studies,particularly in young and middle-aged women,remain underexplored.Objective:To evaluate the effects of an orally administered collagen drink combining CP and EP on the skin health of young and middle-aged women.Materials and Methods:A single-center,randomized,double-blind,parallel-controlled trial was conducted,utilizing the WONDERLABR fish collagen tripeptide beverage.Participants consumed the drink over an 8-week period.Results:Compared to the placebo group,the collagen drink group showed significant improvements in skin hydration(39.19%increase),transepidermal water loss(33.45%decrease),skin elasticity(25.37%increase),dermal collagen content(21.64%increase),pore size(7.94%decrease),wrinkle length(18.09%decrease),skin smoothness(2.85%improvement),and skin roughness(15.32%decrease).Overall pore volume decreased by 60%,and visual assessments indicated a decrease in skin luminosity by 15.20%and smoothness index by 22.55%.Mass spectrometry demonstrated a significant increase in collagen efficacy components,including blood pH and GPH levels(P<0.05).Conclusion:The study confirmed the combination nourishing and anti-skin aging effects of EP and CP on the skin of young and middle-aged women,demonstrating significant improvements in various skin parameters and good bioavailability of collagen peptides.

Estimation of cancer cell migration in biomimetic random/oriented collagen fiber microenvironments

Increasing data indicate that cancer cell migration is regulated by extracellular matrixes and their surrounding biochemical microenvironment,playing a crucial role in pathological processes such as tumor invasion and metastasis.However,conventional two-dimensional cell culture and animal models have limitations in studying the influence of tumor microenvironment on cancer cell migration.Fortunately,the further development of microfluidic technology has provided solutions for the study of such questions.We utilize microfluidic chip to build a random collagen fiber microenvironment(RFM)model and an oriented collagen fiber microenvironment(OFM)model that resemble early stage and late stage breast cancer microenvironments,respectively.By combining cell culture,biochemical concentration gradient construction,and microscopic imaging techniques,we investigate the impact of different collagen fiber biochemical microenvironments on the migration of breast cancer MDA-MB-231-RFP cells.The results show that MDA-MB-231-RFP cells migrate further in the OFM model compared to the RFM model,with significant differences observed.Furthermore,we establish concentration gradients of the anticancer drug paclitaxel in both the RFM and OFM models and find that paclitaxel significantly inhibits the migration of MDA-MB-231-RFP cells in the RFM model,with stronger inhibition on the high concentration side compared to the low concentration side.However,the inhibitory effect of paclitaxel on the migration of MDA-MB-231-RFP cells in the OFM model is weak.These findings suggest that the oriented collagen fiber microenvironment resembling the late-stage tumor microenvironment is more favorable for cancer cell migration and that the effectiveness of anticancer drugs is diminished.The RFM and OFM models constructed in this study not only provide a platform for studying the mechanism of cancer development,but also serve as a tool for the initial measurement of drug screening.

3D-bioprinted tri-layered cellulose/collagen-based drug-eluting fillers for the treatment of deep tunneling wounds

Tunneling wounds create passageways underneath the skin surface with varying sizes and shapes and can have twists and turns,making their treatment extremely difficult.Available wound care solutions only cater to superficial wounds,and untreated tunneling wounds pose major health concerns.This study aims to fulfill this challenge by fabricating tunnel wound fillers(TWFs)made of natural polymers that mimic the dermal extracellular matrix.In this study,cellulose microfibers(CMFs)derived from banana stem and fish skin-derived collagen were used to formulate bio-inks with varying CMF contents(25,50,and 75 mg).Tri-layered(CMFs,primary and secondary collagen coatings),drug-eluting(Baneocin),and cell-laden(human mesenchymal stem cells)TWFs were three-dimensional(3D)-printed and extensively characterized.CMFs showed the most suitable rheological properties for 3D printing at 50 mg concentration.The Alamar Blue data showed significantly increased cell proliferation from Day 1 to Day 7,and scratch tests used to evaluate in vitro wound healing revealed that the best coverage of the wound area was achieved using CMFs in combination with collagen and alginate.Finally,the TWF showed promising capability and tunability in terms of wound shape and size upon testing on a chicken tissue model.The results demonstrate the tremendous potential of TWFs in treating deep tunneling wounds with unique advantages,such as patient-specific customization,good wound exudate absorption capability while releasing wound healing drugs,and the inclusion of stem cells for accelerated healing and tissue regeneration.

Anti-abrasion collagen fiber-based membrane functionalized by UiO-66-NH_(2)with ultra-high efficiency and stability for oil-in-water emulsions separation

Membrane separation strategies offer promising platform for the emulsion separation.However,the low mechanical strength of membrane separation layers and the trade-off between separation flux and efficiency present significant challenges.In this study,we report a CFM@UiO-66-NH_(2)membrane with high separation flux,efficiency and stability,through utilizing a robust anti-abrasion collagen fiber membrane(CFM)as the multifunctional support and UiO-66-NH_(2)by an in-situ growth as the separation layer.The high mechanical strength of the CFM compensated for the weakness of the separation layer,while the charge-breaking effect of UiO-66-NH_(2),along with the size sieving of its constituent separating layers and the capillary effect of the collagen fibers,contributed to the potential for efficient separation.Additionally,the CFM@UiO-66-NH_(2)membrane exhibited superhydrophilic properties,making it suitable for separating oil-in-water microemulsions and nanoemulsions stabilized by anionic surfactants.The membrane demonstrated remarkable separation efficiencies of up to 99.960%and a separation flux of370.05 L·m^(-2)·h^(-1).Moreover,it exhibits stability,durability,and abrasion resistance,maintaining excellent separation performance even when exposed to strong acids and alkalis without any damage to its structure and performance.After six cycles of reuse,it achieved a separation flux of 417.97 L·m^(-2)·h^(-1)and a separation efficiency of 99.747%.Furthermore,after undergoing 500 cycles of strong abrasion,the separation flux remained at 124.39 L·m^(-2)·h^(-1),with a separation efficiency of 99.992%.These properties make it suitable for the long-term use in harsh operating environments.We attribute these properties to the electrostatic effect resulting from the amino group on UiO-66-NH_(2)and its in-situ growth on the CFM,which forms a size-screening separation layer.Our work highlights the potential of the CFM@UiO-66-NH_(2)membrane as an environmentally friendly size-screening material for the efficient emulsion wastewater separation.

Acupotomy ameliorates knee osteoarthritis-related collagen deposition and fibrosis in rabbit skeletal muscle through the TGF-β/Smad pathway

Objective:To investigate the effects of acupotomy on skeletal muscle fibrosis and collagen deposition in a rabbit knee osteoarthritis(KOA)model.Methods: Rabbits(n=18)were randomly divided into control,KOA,and KOA+acupotomy(Apo)groups(n=6).The rabbits in the KOA and Apo groups were modeled using the modified Videman's method for 6 weeks.After modeling,the Apo group was subjected to acupotomy once a week for 3 weeks on the vastus medialis,vastus lateralis,rectus femoris,biceps femoris,and anserine bursa tendons around the knee.The behavior of all animals was recorded,rectus femoris tissue was obtained,and histomorphological changes were observed using Masson staining and transmission electron microscopy.The expression of transforming growth factor-β1(TGF-β1),Smad 3,Smad 7,fibrillar collagen types I(Col-I)and III(Col-III)was detected using Western blot and real-time polymerase chain reaction(RT-PCR).Results: Histological analysis revealed that acupotomy improved the microstructure and reduced the collagen volume fraction of rectus femoris,compared with the KOA group(P=.034).Acupotomy inhibited abnormal collagen deposition by modulating the expression of fibrosis-related proteins and mRNA,thus preventing skeletal muscle fibrosis.Western blot and RT-PCR analysis revealed that in the Apo group,Col-I,and Col-III protein levels were significantly lower than those in the KOA group(both P<.01),same as Col-I and Col-III mRNA levels(P=.0031;P=.0046).Compared with the KOA group,the protein levels of TGF-β1 and Smad 3 were significantly reduced(both P<.01),as were the mRNA levels of TGF-β1 and Smad 3(P=.0007;P=.0011).Conversely,the levels of protein and mRNA of Smad 7 were significantly higher than that in the KOA group(P<.01;P=.0271).Conclusion: Acupotomy could alleviate skeletal muscle fibrosis and delay KOA progress by inhibiting collagen deposition through the TGF-β/Smad pathway in the skeletal muscle of KOA rabbits.

Skin care efficacy study of recombinant humanized collagen based on in vitro level

Studying the skin care efficacy of recombinant humanized collagen based on in vitro level.The stability of the recombinant humanized collagen was first analyzed by treating at different temperatures,then its skincare efficacy based on in vitro level was evaluated by detecting the inhibition rate of elastase,the inhibition rate of collagenase,the protein content of type I collagen in human fibroblasts,the inhibition of reactive oxygen species(ROS)with human keratinocytes,and the effects of the recombinant humanized collagen on the expression of hyaluronic acid(HA),filaggrin(FLG)and transglutaminase 1(TGM1)in keratinocytes.The results showed that recombinant humanized collagen was able to maintain stability at temperatures below 70℃.With regard to its skincare efficacy,recombinant humanized collagen could inhibit elastase and collagenase activities and promote the increase of type I collagen content in human fibroblasts.It also showed good inhibition of ROS in keratinocytes in vitro and could increase the expression of HA,FLG,and TGM1 in keratinocytes.In short,the recombinant humanized collagen exhibited a favourable skin care effect in vitro level.This study proved that it has potential firming,anti-wrinkle,moisturizing,and repairing efficacy,and is a valuable cosmetic raw material.

Exosomes from umbilical cord mesenchymal stromal cells promote the collagen production of fibroblasts from pelvic organ prolapse

BACKGROUND Pelvic organ prolapse(POP)involves pelvic organ herniation into the vagina due to pelvic floor tissue laxity,and vaginal structure is an essential factor.In POP,the vaginal walls exhibit abnormal collagen distribution and decreased fibroblast levels and functions.The intricate etiology of POP and the prohibition of trans-vaginal meshes in pelvic reconstruction surgery present challenges in targeted therapy development.Human umbilical cord mesenchymal stromal cells(hucMSCs)present limitations,but their exosomes(hucMSC-Exo)are promising therapeutic tools for promoting fibroblast proliferation and extracellular matrix remodeling.suppressed inflammation in POP group fibroblasts,stimulated primary fibroblast growth,and elevated collagen I(Col1)production in vitro.High-throughput RNA-seq of fibroblasts treated with hucMSC-Exo and miRNA sequencing of hucMSC-Exo revealed that abundant exosomal miRNAs downregulated matrix metalloproteinase 11(MMP11)expression.CONCLUSION HucMSC-Exo normalized the growth and function of primary fibroblasts from patients with POP by promoting cell growth and Col1 expression in vitro.Abundant miRNAs in hucMSC-Exo targeted and downregulated MMP11 expression.HucMSC-Exo-based therapy may be ideal for safely and effectively treating POP.

Tissue Regeneration in Infected Wounds of Albino Rats Using Ciprofloxacin-Loaded Gelatin Microspheres Incorporated Collagen Scaffold: A Histological Approach with H&E Staining

A wound care system consisting of ciprofloxacin-loaded gelatin microspheres impregnated in a macroporous collagen scaffold was created to effectively control wound infection and regenerate soft tissue at the wound site.Histological and biochemical alterations were observed in infected wounds treated with these scaffolds in Albino Wistar rats.Furthermore,the study examined the immediate and prolonged release of ciprofloxacin from the scaffolds,as well as their function in eliminating bacterial infections and expediting the process of skin healing and regeneration.The developed technique was followed in the streamlined process of creating these collagen scaffolds.Compared to untreated wounds,the group receiving scaffold treatment experienced a faster rate of wound closure.It was noted that the rate of infections was considerably reduced and that full soft tissue regeneration occurred within 12 days.The development of well-deposited collagen bundles in the treated groups was demonstrated by H&E staining,which verified the flawless regeneration of the dermis and epidermis.The antimicrobial agent-loaded gelatin microspheres impregnated into the porous collagen scaffold demonstrated remarkable soft tissue regeneration and efficient infection control at the wound site.

The Combined Effect of Lumenato and Ceramide in the Protection of Collagen Damage Induced by Neutrophils in Normal Human Dermal Fibroblasts

Introduction: Collagen is the primary structural protein fibroblasts produce in the skin’s extracellular matrix. Infiltration of neutrophils into the epidermis and dermis by exposure to UV causes collagen damage and contributes to photoaging. Methods: To study the combined effect of Lumenato and ceramide in preventing collagen-1 damage induced by phagocytes, we used co-cultures of normal human dermal fibroblasts (fibroblasts) and activated human neutrophils. The present study aimed to determine the protective effect of the combination of Lumenato and ceramide on fibroblast collagen-1 damage induced by neutrophils. Results: Lumenato (in the range of 6.5 - 208 μg/ml) or ceramide (in the range of 0.1 - 50 μM) inhibited the production of superoxides and MPO by TNFα-stimulated neutrophils, as well as the production of NO by LPS-stimulated macrophages in a dose-dependent manner. The combinations of Lumenato and ceramide, in low concentrations, caused synergistic prevention of fibroblasts’ collagen-1 damage induced by TNFα-activated neutrophils, detected by fluorescence immunostaining and WB analysis. MPO activity in the supernatants of the co-cultures was also synergistically inhibited. Adding Lumenato or ceramide singly or in combinations in these low concentrations to the fibroblast cultures did not affect the expression of collagen-1. The combinations of Lumenato or ceramide in these concentrations also caused a synergistic inhibition of NO production by activated macrophages. Conclusions: The results suggest that combining low concentrations of Lumenato and ceramide results in synergistic protection against fibroblasts’ collagen-1 damage induced by neutrophils, thus indicating their possible potential for enhanced skin health.

3D Collagen Gels:A Promising Platform for Dendritic Cell Culture in Biomaterials Research

The three-dimensional(3D)cell culture system has garnered significant attention in recent years as a means of studying cell behavior and tissue development,as opposed to traditional two-dimensional cultures.These systems can induce specific cell reactions,promote specific tissue functions,and serve as valuable tools for research in tissue engineering,regenerative medicine,and drug discovery.This paper discusses current developments in the field of three-dimensional cell culture and the potential applications of 3D type 1 collagen gels to enhance the growth and maturation of dendritic cells.

Ideal Bi‑Based Hybrid Anode Material for Ultrafast Charging of Sodium‑Ion Batteries at Extremely Low Temperatures

Sodium-ion batteries have emerged as competitive substitutes for low-temperature applications due to severe capacity loss and safety concerns of lithium-ion batteries at−20°C or lower.However,the key capability of ultrafast charging at ultralow temperature for SIBs is rarely reported.Herein,a hybrid of Bi nanoparticles embedded in carbon nanorods is demonstrated as an ideal material to address this issue,which is synthesized via a high temperature shock method.Such a hybrid shows an unprecedented rate performance(237.9 mAh g^(−1)at 2 A g^(−1))at−60℃,outperforming all reported SIB anode materials.Coupled with a Na_(3)V_(2)(PO_(4))_(3)cathode,the energy density of the full cell can reach to 181.9 Wh kg^(−1)at−40°C.Based on this work,a novel strategy of high-rate activation is proposed to enhance performances of Bi-based materials in cryogenic conditions by creating new active sites for interfacial reaction under large current.

Activation of adult endogenous neurogenesis by a hyaluronic acid collagen gel containing basic fibroblast growth factor promotes remodeling and functional recovery of the injured cerebral cortex

The presence of endogenous neural stem/progenitor cells in the adult mammalian brain suggests that the central nervous system can be repaired and regenerated after injury.However,whether it is possible to stimulate neurogenesis and reconstruct cortical layers II to VI in non-neurogenic regions,such as the cortex,remains unknown.In this study,we implanted a hyaluronic acid collagen gel loaded with basic fibroblast growth factor into the motor cortex immediately following traumatic injury.Our findings reveal that this gel effectively stimulated the proliferation and migration of endogenous neural stem/progenitor cells,as well as their differentiation into mature and functionally integrated neurons.Importantly,these new neurons reconstructed the architecture of cortical layers II to VI,integrated into the existing neural circuitry,and ultimately led to improved brain function.These findings offer novel insight into potential clinical treatments for traumatic cerebral cortex injuries.

融合注意力机制和Bi-YOLO的变电站异物检测研究

由于变电站内设备悬挂异物的现象频发,为预防站内人员巡检不及时导致电力事故发生,在YOLOv5的基础上,提出融合注意力机制和Bi-YOLO的变电站异物检测研究。采用加权双向特征金字塔替代原有的特征金字塔网络,将坐标注意力模块嵌入C3结构,添加混合注意力模块,以提高变电站异物的特征提取能力和检测效率。实验结果显示,相较于YOLOv5算法,提出的检测算法多类别平均检测精度提高3.3%,mAP值达91.3%,满足实时性要求。

Bio-Oss Collagen治疗牙周炎骨下袋的临床疗效观察

目的评价Bio—OssCollagen治疗牙周骨下袋的临床效果。方法选择全身健康的牙用基础治疗后6周左右的慢性牙周炎患者10例,男性6例,女性4例,平均年龄40．8岁,共有18处骨下袋,试验组9处骨下袋17个位点。对照组9处骨下袋15个位点。牙周翻瓣术分别植入Bio-Om Collagen(试验组)和Bio-Oss(对照组)。分别在手术前和手术后6个月检查牙周袋探诊深度(PD)、牙龈出血指数(BI)、牙龈退缩(GR)和临床附着水平(C地),拍摄术区平行定位X线片评价植骨前后骨缺损处牙槽骨的修复情况。结果植骨前两组的各项指标阃无显著性差异。Bio-Om CoUagen组植骨前的PD(6．6±1．2mm)、BI(2．7±0．8)、GR(2．2±0．8mm)和CAl．,(8．8±1．3mm),植骨后6个月分则为PD(3．8±0．9ram)、BI(1．9±0．7)、GR(2．4±1．Imm)和CAL(6．2士1．2mm);Bio -Oss组植骨前的PD(6．1±1．0mm)、BI(2．2±0．7)、GR(1．9±1．5mm)和CAL(8．0±2．0mm),植骨后6个月分别为PD(4．0±0．7mm)、BI(1．9±0．7)、GR(1．9±1．2mm)和CAL(5．9±1．6mm),两组PD和CAL以及试验组BI的改变均有明显的统计学意义(P<O．05),GR在治疗前后均无显著差异。Bio一Oss Collagen组PD的降低(2．8±0．9mm)要明显大于Bio-Oss组(2．0±1．0mm)(P<0．05)。余指标则均无显著性差异。比较治疗前后的X线片。膏缺损处牙槽骨均明显增加。结论Bio-Oss CoUagen和Bio—Oss两种骨材料均可明显地降低牙周袋探诊深度和减少附着丧失,奉研宽中Bio-Oss CoHagen要优于Bio-0ss,而且临床操作较方便。

Bio-Oss Collagen联合不同软组织处理方式行拔牙位点保存术对前牙区拔牙后骨组织的影响

目的:探究Bio-Oss Collagen联合不同软组织处理方式行拔牙位点保存术对前牙区拔牙后组织的影响。方法:选取2015年4月-2018年4月于本院口腔种植科就诊的前牙需要拔除患者61例(患牙61颗),根据不同软组织处理方式分为A组(n=16)、B组(n=10)、C组(n=12)、D组(n=13)与E组(n=10)。A组植入Bio-Oss Collagen联合Bio-Guide生物膜;B组植入Bio-Oss Collagen联合可吸收性明胶海绵;C组植入Bio-Oss Collagen联合自体软组织瓣;D组植入单纯Bio-Oss Collagen;E组自行愈合。比较五组术后6个月骨量、黏膜量、牙槽骨密度、牙槽嵴骨吸收量、牙槽嵴高度和宽度、拔牙位点高度和宽度及前牙美学区满意情况。结果:术后6个月,A、B、C、D组牙槽骨高度与宽度变化均值、垂直向骨吸收量、牙槽嵴高度变化绝对值、拔牙位点唇腭侧高度及宽度变化值均低于E组,而新骨所占面积及黏膜面积变化、牙槽骨密度、牙槽嵴唇腭侧高度、根长50%与70%处牙槽嵴宽度、软组织色泽、软组织附着高度及咀嚼功能恢复满意率均高于E组(P<0.05)。A、B、C组中,骨高度与宽度变化均值均为A组<C组<B组(P<0.05)。A、B、C组新骨所占面积、黏膜面积变化与根长50%处牙槽嵴宽度均高于D组,且A组>C组>B组(P<0.05)。A、B、C组唇腭向骨吸收量、拔牙位点唇腭侧高度及宽度变化值均低于D组,且A组<C组<B组(P<0.05)。结论:Bio-Oss Collagen联合Bio-Guide生物膜有助于减慢牙槽嵴吸收,在保留骨量、黏膜量及拔牙位点中具有一定的临床价值,可在临床种植修复的技术中推广使用。

铸态下Sn-Bi二元共晶焊料合金的组织特征及其力学性能

研究了四种不同Bi含量(45%、50%、55%、60%)的Sn-Bi二元共晶合金自由凝固下的组织特征和力学性能,探讨了Sn-Bi二元共晶合金的晶体生长机制以及Bi元素含量对合金显微组织的影响。结果表明:Sn-Bi二元亚共晶合金铸态下的金相组织为初生Sn固溶体相和Sn/Bi共晶层片集群构成,随着Bi含量的增加,呈树枝晶形态生长的初生Sn相数量减少,形态长大。初生Sn固溶体相内部脱溶析出大量的杆状或点状Bi相,形成杆状共晶结构;Sn-Bi二元过共晶合金铸态下的金相组织为初生Bi相和Sn/Bi共晶层片集群构成,初生Bi相中基本不固溶Sn元素,呈小平面方式生长,并在在初生Bi相周围包裹生长一层Sn晕圈相。在室温下,Sn-Bi二元共晶合金的硬度和强度随着Bi含量的增加而上升,延伸率随着Bi含量的增加先上升后下降。

基于不同Bi2WO6形貌下光催化降解四环素性能研究

该文以Bi(NO3)3·5H2O和Na2WO4·2H2O为原料通过水热法合成Bi2WO6,重点研究通过改变水合加热时间和溶液酸碱性,不同合成条件对Bi2WO6产物形貌的影响.借助扫描电子显微镜(SEM)对Bi2WO6形貌进行分析.实验结果显示,溶液酸碱性和加热时间均对Bi2WO6的形貌有较大影响,水合加热时间也对其形貌有很大的影响.此外,通过在可见光下降解四环素(TC),探讨了不同合成条件对催化剂性能的影响.实验结果表明,酸碱性会破坏Bi2WO6的结构,进而降低其光催化性能.当水合加热时间为25 h时,Bi2WO6的降解效率最高,降解效果约为50%.

Mg-Bi系合金的研究进展

合金元素Bi的价格较低,在镁中有较高的固溶度,随着温度降低,其固溶度减小,析出Mg_(3)Bi_(2)相,提高了镁的力学性能,因此Mg-Bi系合金具有良好的固溶和时效硬化潜力。在Mg-Bi系合金中加入Sn、Mn、Al、Ca、Zn等元素,改善合金组织,能够进一步提高合金的力学性能及耐腐蚀性。文中介绍了国内外学者对Mg-Bi系合金的研究进展,在总结Mg-Bi二元合金研究成果基础上,系统的概述了Mg-Bi-Sn系、Mg-Bi-Mn系、Mg-Bi-Al系、Mg-Bi-Ca系、Mg-Bi-Zn系等合金的组织和性能,综述了合金化对合金第二相、晶粒尺寸、织构、动态再结晶的影响,阐述了合金元素种类、添加量及热加工参数与合金力学性能的关系。总结了Mg-Bi系合金研究中存在的问题,并对今后的研究工作进行了展望。