Potential therapeutic role of spermine via Rac1 in osteoporosis:Insights from zebrafish and mice

Osteoporosis(OP)is a prevalent metabolic bone disease.While drug therapy is essential to prevent bone loss in osteoporotic patients,current treatments are limited by side effects and high costs,necessitating the development of more effective and safer targeted therapies.Utilizing a zebrafish(Danio rerio)larval model of osteoporosis,we explored the influence of the metabolite spermine on bone homeostasis.Results showed that spermine exhibited dual activity in osteoporotic zebrafish larvae by increasing bone formation and decreasing bone resorption.Spermine not only demonstrated excellent biosafety but also mitigated prednisolone-induced embryonic neurotoxicity and cardiotoxicity.Notably,spermine showcased protective attributes in the nervous systems of both zebrafish embryos and larvae.At the molecular level,Rac1 was identified as playing a pivotal role in mediating the antiosteoporotic effects of spermine,with P53 potentially acting downstream of Rac1.These findings were confirmed using mouse(Mus musculus)models,in which spermine not only ameliorated osteoporosis but also promoted bone formation and mineralization under healthy conditions,suggesting strong potential as a bonestrengthening agent.This study underscores the beneficial role of spermine in osteoporotic bone homeostasis and skeletal system development,highlighting pivotal molecular mediators.Given their efficacy and safety,human endogenous metabolites like spermine are promising candidates for new anti-osteoporotic drug development and daily bone-fortifying agents.

Recent advances in cell sheet technology for bone and cartilage regeneration: from preparation to application

Bone defects caused by trauma,tumour resection,infection and congenital deformities,together with articular cartilage defects and cartilage–subchondral bone complex defects caused by trauma and degenerative diseases,remain great challenges for clinicians.Novel strategies utilising cell sheet technology to enhance bone and cartilage regeneration are being developed.The cell sheet technology has shown great clinical potential in regenerative medicine due to its effective preservation of cell–cell connections and extracellular matrix and its scaffold-free nature.This review will first introduce several widely used cell sheet preparation systems,including traditional approaches and recent improvements,as well as their advantages and shortcomings.Recent advances in utilising cell sheet technology to regenerate bone or cartilage defects and bone–cartilage complex defects will be reviewed.The key challenges and future research directions for the application of cell sheet technology in bone and cartilage regeneration will also be discussed.

Temperature stability and microstructure of ultra-high intrinsic coercivity Nd-Fe-B magnets

The variations of intrinsic coercivity and remanence of sintered Nd-Fe-B magnets with ultra-high intrinsic coercivity were investigated. The results showed that the intrinsic coercivity and remanence declined simultaneously with increasing temperature, but the squareness of the magnets has hardly been changed. The temperature coefficients of remanence （α） and coercivity （β） for the magnets were calculated by two different methods, and the variations of the temperature coefficients and the microstructure of sintered Nd-Fe-B magnets were analyzed. The temperature coefficients of remanence （α） and coercivity （β） for the sintered magnets are very small, and the existence of fine microstructure is necessary to obtain sintered Nd-Fe-B magnets with ultra-high intrinsic coercivity.

Adhesion-enhancing coating embedded with osteogenesis-promoting PDA/HA nanoparticles for peri-implant soft tissue sealing and osseointegration

Following dental implantation,the characteristic bacterial milieu of the oral cavity may lead to peri-implant inflammation,which can negatively impact osseointegration and cause implant failure.To improve soft tissue sealing around the implant,enhance osseointegration,and improve implant success rates,this paper proposes a composite multifunctional coating(PHG)prepared using gelatin and polydopamine/hydroxyapatite nanoparticles,investigates the effects of this novel coating on cell adhesion,proliferation,antibacterial activity,osteogenic differentiation,and evaluates its immune-related properties.The PHG coating was proved to have satisfactory hydrophilicity and wettability for cell attachment.Furthermore,it improved the expression of adhesion-related genes and proteins in human gingival fibroblasts,indicating its adhesion-promoting effect.Additionally,bone marrow mesenchymal stem cells exhibited strong osteogenic differentiation potential and mineralization on PHG-coated surfaces.Notably,the PHG coating exhibited antibacterial activity against Streptococcus mutans,as well as anti-inflammatory effects,potentially via the regulation of macrophages.Therefore,the proposed PHG coating may promote soft tissue sealing and bone bonding,providing a potential strategy for the surface modification of dental implants.

Domain Structure and Magnetization Process in Short Glass-Coated Amorphous Microwires with Positive Magnetostriction

The domain structure and magnetisation process in short glass-coated amorphous Fe45Co20Ni10Si9B16 microwires are investigated by analyzing the hysteresis loops measured by a vibrating sample magnetometer.Methods of calculating the thickness of the outer shell and the critical length to observe magnetic bistability have been established.The thickness of the outer shell is 2.3μm and the critical length is 8.11 mm for a microwire with a metallic core diameter of 31.1μm and a glass coat thickness of 10.6μm.The experimental results demonstrate the reliability of this method to calculate the critical length.

Micromechanical interlocking structure at the filler/resin interface for dental composites: a review

Dental resin composites(DRCs)are popular materials for repairing caries or dental defect,requiring excellent properties to cope with the complex oral environment.Filler/resin interface interaction has a significant impact on the physicochemical/biological properties and service life of DRCs.

Wetting of MXenes and Beyond

MXenes are a class of 2D nanomaterials with exceptional tailormade properties such as mechano-ceramic nature,rich chemistry,and hydrophilicity,to name a few.However,one of the most challenging issues in any composite/hybrid system is the interfacial wetting.Having a superior integrity of a given composite system is a direct consequence of the proper wettability.While wetting is a fundamental feature,dictating many physical and chemical attributes,most of the common nanomaterials possesses poor affinity due to hydrophobic nature,making them hard to be easily dispersed in a given composite.Thanks to low contact angle,MXenes can offer themselves as an ideal candidate for manufacturing different nano-hybrid structures.Herein this review,it is aimed to particularly study the wettability of MXenes.In terms of the layout of the present study,MXenes are first briefly introduced,and then,the wettability phenomenon is discussed in detail.Upon reviewing the sporadic research efforts conducted to date,a particular attention is paid on the current challenges and research pitfalls to light up the future perspectives.It is strongly believed that taking the advantage of MXene’s rich hydrophilic surface may have a revolutionizing role in the fabrication of advanced materials with exceptional features.

Strontium-incorporated bioceramic scaffolds for enhanced osteoporosis bone regeneration

The restoration of bone defects caused by osteoporosis remains a challenge for surgeons.Strontium ranelate has been applied in preventative treatment approaches due to the biological functions of the trace element strontium(Sr).In this study,we aimed to fabricate bioactive scaffolds through Sr incorporation based on our previously developed modified amino-functional mesoporous bioactive glass(MBG)and to systematically investigate the bioactivity of the resulting scaffold in vitro and in vivo in an osteoporotic rat model.The results suggested that Sr-incorporated amino-functional MBG scaffolds possessed favorable biocompatibility.Moreover,with the incorporation of Sr,osteogenic and angiogenic capacities were upregulated in vitro.The in vivo results showed that the Sr-incorporated amino-functional MBG scaffolds achieved better bone regeneration and vessel formation.Furthermore,bioinformatics analysis indicated that the Sr-incorporated amino-functional MBG scaffolds could reduce reactive oxygen species levels in bone marrow mesenchymal stem cells in the osteoporotic model by activating the cAMP/PKA signaling pathway,thus playing an anti-osteoporosis role while promoting osteogenesis.This study demonstrated the feasibility of incorporating trace elements into scaffolds and provided new insights into biomaterial design for facilitating bone regeneration in the treatment of osteoporosis.

The osteogenesis of Ginsenoside Rb1 incorporated silk/micro-nano hydroxyapatite/sodium alginate composite scaffolds for calvarial defect

Ginsenoside Rb1, the effective constituent of ginseng, has been demonstrated to play favorable roles in improving the immunity system. However, there is little study on the osteogenesis and angiogenesis effect of Ginsenoside Rb1. Moreover, how to establish a delivery system of Ginsenoside Rb1 and its repairment ability in bone defect remains elusive. In this study, the role of Ginsenoside Rb1 in cell viability, proliferation, apoptosis, osteogenic genes expression, ALP activity of rat BMSCs were evaluated firstly. Then,micro-nano HAp granules combined with silk were prepared to establish a delivery system of Ginsenoside Rb1, and the osteogenic and angiogenic effect of Ginsenoside Rb1 loaded on micro-nano HAp/silk in rat calvarial defect models were assessed by sequential fluorescence labeling, and histology analysis, respectively. It revealed that Ginsenoside Rb1 could maintain cell viability, significantly increased ALP activity, osteogenic and angiogenic genes expression. Meanwhile, micro-nano HAp granules combined with silk were fabricated smoothly and were a delivery carrier for Ginsenoside Rb1. Significantly, Ginsenoside Rb1 loaded on micro-nano HAp/silk could facilitate osteogenesis and angiogenesis. All the outcomes hint that Ginsenoside Rb1 could reinforce the osteogenesis differentiation and angiogenesis factor’s expression of BMSCs. Moreover, micro-nano HAp combined with silk could act as a carrier for Ginsenoside Rb1 to repair bone defect.

MXene-Based Composites as Nanozymes in Biomedicine: A Perspective

MXene-based nanozymes have garnered considerable attention because of their potential environmental and biomedical applications.These materials encompass alluring and manageable catalytic performances and physicochemical features,which make them suitable as(bio)sensors with high selectivity/sensitivity and efficiency.MXene-based structures with suitable electrical conductivity,biocompatibility,large surface area,optical/magnetic properties,and thermal/mechanical features can be applied in designing innovative nanozymes with area-dependent electrocatalytic performances.Despite the advances made,there is still a long way to deploy MXene-based nanozymes,especially in medical and healthcare applications;limitations pertaining the peroxidaselike activity and sensitivity/selectivity may restrict further practical applications of pristine MXenes.Thus,developing an efficient surface engineering tactic is still required to fabricate multifunctional MXene-based nanozymes with excellent activity.To obtain MXene-based nanozymes with unique physicochemical features and high stability,some crucial steps such as hybridization and modification ought to be performed.Notably,(nano)toxicological and long-term biosafety analyses along with clinical translation studies still need to be comprehensively addressed.Although very limited reports exist pertaining to the biomedical potentials of MXene-based nanozymes,the future explorations should transition toward the extensive research and detailed analyses to realize additional potentials of these structures in biomedicine with a focus on clinical and industrial aspects.In this perspective,therapeutic,diagnostic,and theranostic applications of MXene-based nanozymes are deliberated with a focus on future per-spectives toward more successful clinical translational studies.The current state-of-the-art biomedical advances in the use of MXene-based nanozymes,as well as their developmental challenges and future prospects are also highlighted.In view of the fascinating properties of MXene-based nanozymes,these materials can open significant new opportunities in the future of bio-and nanomedicine.

Establishment and assessment of rodent models of medication-related osteonecrosis of the jaw(MRONJ)

Medication-related osteonecrosis of the jaw(MRONJ)is primarily associated with administering antiresorptive or antiangiogenic drugs.Despite significant research on MRONJ,its pathogenesis and effective treatments are still not fully understood.Animal models can be used to simulate the pathophysiological features of MRONJ,serving as standardized in vivo experimental platforms to explore the pathogenesis and therapies of MRONJ.Rodent models exhibit excellent effectiveness and high reproducibility in mimicking human MRONJ,but classical methods cannot achieve a complete replica of the pathogenesis of MRONJ.Modified rodent models have been reported with improvements for better mimicking of MRONJ onset in clinic.This review summarizes representative classical and modified rodent models of MRONJ created through various combinations of systemic drug induction and local stimulation and discusses their effectiveness and efficiency.Currently,there is a lack of a unified assessment system for MRONJ models,which hinders a standard definition of MRONJ-like lesions in rodents.Therefore,this review comprehensively summarizes assessment systems based on published peer-review articles,including new approaches in gross observation,histological assessments,radiographic assessments,and serological assessments.This review can serve as a reference for model establishment and evaluation in future preclinical studies on MRONJ.

Plant Pollen Grains:A Move Towards Green Drug and Vaccine Delivery Systems

Pollen grains and plant spores have emerged as innovative biomaterials for various applications such as drug/vaccine delivery,catalyst support,and the removal of heavy metals.The natural microcapsules comprising spore shells and pollen grain are designed for protecting the genetic materials of plants from exterior impairments.Two layers make up the shell,the outer layer(exine)that comprised largely of sporopollenin,and the inner layer(intine)that built chiefly of cellulose.These microcapsule shells,namely hollow sporopollenin exine capsules have some salient features such as homogeneity in size,non-toxic nature,resilience to both alkalis and acids,and the potential to withstand at elevated temperatures;they have displayed promising potential for the microencapsulation and the controlled drug delivery/release.The important attribute of mucoadhesion to intestinal tissues can prolong the interaction of sporopollenin with the intestinal mucosa directing to an augmented effectiveness of nutraceutical or drug delivery.Here,current trends and prospects related to the application of plant pollen grains for the delivery of vaccines and drugs and vaccine are discussed.

Giant Stress-Impedance Effect in Co_(71.8)Fe_( 4.9)Nb_(0.8)Si_(7.5)B_(15) Glass-Covered Amorphous Wires

The giant stress-impedance （GSI） effect in as-cast and DC current annealed Co71.8Fe4.9 Nb0.8Si7.5 B15 amorphous glass-covered wires is presented. The SI ratio of the as-cast sample exhibits negative GSI effect. For the sample annealed by 60 mA DC current, the SI ratio first increases with applied tensile stress, then decreases. The maximum ΔZ/Z ratio of 304% is obtained. Frequency dependence in the range from 1 to 110 MHz of the GSI effect is investigated. Experimental results show that the real part R and the imaginary part X of impedance play an important role at high frequency and low frequency, respectively. At 1 MHz, the maximum AX/X ratio of 1448% is obtained. At 110 MHz, the maximum AR/R ratio of 648% is obtained.

Magnetoelastic Anisotropy of FeSiB Glass-Coated Amorphous Microwires

The magnetoelastic anisotropy of Fe77.5Si7.5B15 glass-coated amorphous microwires is investigated by the law of approach to saturation magnetization in comparison with the ferromagnetic resonance technique.The anisotropy field of the inner core determined by the former method is 7.6×10^(4) A/m,which is larger than the value 2.5×10^(4) A/m measured by the ferromagnetic resonance method.This difference is ascribed to the skin effect and the uneven distribution of the internal stresses.However,the anisotropy field of the outer shell has a negative value indicating that it has an easy basal plane.

Dielectric behaviors at microwave frequencies and Mossbauer effects of chalcedony, agate, and zultanite

In this study, dielectric properties within 8-12 GHz microwave frequencies, inductively coupled plasma-atomic emis- sion spectrometry, Fourier transform infrared spectrometry, synchronized two thermal analyses, and 57Fe Mossbauer spectroscopy analysis of chalcedony, agate, and zultanite samples from Turkey are presented. Agate and chalcedony show the same nine vibrational absorption peaks obtained unlike zultanite from FTIR spectra in the 350 cm-1 to 4000 cm-1 range, ε＇ values of chalcedony, agate and zultanite derived at 10.5 GHz were 4.67, 4.41, and 7.34, respectively, eI and e~ values of the studied samples at the microwave frequencies are related to the percentage weight of their constituent parts in their chemical compositions. 57Fe Mossbauer spectroscopy results confirm the existence of iron-containing islands in the crystal structure of zultanite, agate, and chalcedony samples, equipped them with magnetic features typical for magnetic nanoparticles including superparamagnetism. The presence of iron-containing islands significantly affects the magnetic, dielectric, and optical properties of studied samples that are not observed for pure minerals without any foreign inclusions.

Selective and effective oxidation of 5-hydroxymethylfurfural by tuning the intermediates adsorption on Co-Cu-CN_(x)

Co-based catalysts are promising alternatives to precious metals for the selective and effective oxidation of 5-hydroxymethylfurfural(HMF)to the higher value-added 2,5-furandicarboxylic acid(FDCA).However,these catalysts still suffer from unsatisfactory activity and poor selectivity.A series of N-doped carbon-supported Co-based dual-metal nanoparticles(NPs)have been designed,among which the Co-Cu_(1.4)-CN_(x) exhibits enhanced HMF oxidative activity,achieving FDCA formation rates 4 times higher than that of pristine Co-CN_(x),with 100%FDCA selectivity.Density functional theory(DFT)calculations evidenced that the increased electron density on Co sites induced by Cu can mediate the positive electronegativity offset to downshift the dband center of Co-Cu_(1.4)-CN_(x),thus reducing the energy barriers for the conversion of HMF to FDCA.Such findings will support the development of superior non-precious metal catalysts for HMF oxidation.

Interface optimization of graphene paper-Cu composite prepared by electrodeposition

A room-temperature electrodeposition method with an organic electrolyte was developed to fabricate a HNO3-pretreated graphene paper Cu(GP'-Cu)composite.To improve the interfacial bonding of GP'-Cu composite,magnetron sputtering technology was used to create a"sandwich"structural gradient GP'-Cu composite.The selection of the intermediate transition layer metal was based on two-dimensional disregistry.Scanning electron microscopy,X-ray photoelectron spectroscopy,and other analytical methods confirmed that the addition of an intermediate transition metal(Cr,Ni)layer reduced the gap distance and enhanced the interfacial bonding of the GP'and Cu deposited layers.The GP'-Ni-Cu composite exhibited the largest increase in tensile strength and conductivity.In addition,it had the highest thermal diffusivity and elongation at break among the GP'-Cu,GP'-Cr-Cu and GP'-Ni-Cu composites.

Unraveling the complex roles of macrophages in obese adipose tissue:an overview

Macrophages,a heterogeneous population of innate immune cells,exhibit remarkable plasticity and play pivotal roles in coordinating immune responses and maintaining tissue homeostasis within the context of metabolic diseases.The activation of inflammatory macrophages in obese adipose tissue leads to detrimental effects,inducing insulin resistance through increased inflammation,impaired thermogenesis,and adipose tissue fibrosis.Meanwhile,adipose tissue macrophages also play a beneficial role in maintaining adipose tissue homeostasis by regulating angiogenesis,facilitating the clearance of dead adipocytes,and promoting mitochondrial transfer.Exploring the heterogeneity of macrophages in obese adipose tissue is crucial for unraveling the pathogenesis of obesity and holds significant potential for targeted therapeutic interventions.Recently,the dual effects and some potential regulatory mechanisms of macrophages in adipose tissue have been elucidated using single-cell technology.In this review,we present a comprehensive overview of the intricate activation mechanisms and diverse functions of macrophages in adipose tissue during obesity,as well as explore the potential of drug delivery systems targeting macrophages,aiming to enhance the understanding of current regulatory mechanisms that may be potentially targeted for treating obesity or metabolic diseases.

Effects of Sn Addition on Core Loss and Texture of Non-Oriented Electrical Steels

The effects of Sn addition on core loss and texture of non-oriented electrical steels were investigated. Experiments revealed that the core loss of non-oriented electrical steels could be obviously decreased and the intensity of {111 } texture and { 112} texture of final annealed specimens could be markedly reduced by Sn addition. The reasons for reducing core loss and the intensity of unfavorable texture were analyzed.

Recent Progress in Emerging Two‑Dimensional Transition Metal Carbides

As a new member in two-dimensional materials family,transition metal carbides(TMCs)have many excellent properties,such as chemical stability,in-plane anisotropy,high conductivity and flexibility,and remarkable energy conversation efficiency,which predispose them for promising applications as transparent electrode,flexible electronics,broadband photodetectors and battery electrodes.However,up to now,their device applications are in the early stage,especially because their controllable synthesis is still a great challenge.This review systematically summarized the state-of-the-art research in this rapidly developing field with particular focus on structure,property,synthesis and applicability of TMCs.Finally,the current challenges and future perspectives are outlined for the application of 2D TMCs.