Search Results (150)

From Palaeolithic ornaments to modern biomimetics, the use of nacre and shells has evolved. Initially utilised for jewellery and tools, they now inspire the development of advanced materials. This paper reviews the current knowledge on nacre’s composition, focusing on the highly regulated biomineralisation process wherein amorphous calcium carbonate (ACC) transforms into crystalline aragonite. It examines the important role of the organic matrix (specifically soluble, insoluble, and acidic proteins) in controlling crystal nucleation, growth, and polymorph selection. Scientists study natural nacre formation to create nacre-inspired composites for various applications. Charles Hatchett’s in 1799 shell categorisation, Sorby and Sowerby’s 19th-century microscopy, Taylor, Beedham, Bøggild, and Currey’s mid-20th-century research on bivalve structures, and mechanical property investigations in the 1970s are some of the major developments. The hierarchical structure, cooperative plastic deformation, surface asperities, organic–inorganic interactions, and interphase in such complex composite materials give rise to impressive mechanical properties. In the early 2000s, with the emergence of biomimetics, inspired by nacre, several macroscopic structural materials with uniform micro- and nanoscale architectures have been synthesised in recent decades, and their mechanical properties and potential applications have been explored. Modern nacre-inspired fabrication utilises 3D printing for precision, freeze casting for sustainability, and mineralisation for scalability. Techniques like layer-by-layer assembly and nanomaterial integration enhance mechanical performance through advanced interfacial engineering. Full article

Bone regeneration in critical-size defects requires biomaterials that provide both structural support and appropriate osteoinductive cues. Natural nacre contains an organic matrix rich in acidic macromolecules with reported osteogenic activity; however, its in vivo regenerative potential remains insufficiently explored. This study evaluated the bone regenerative capacity of nacre-derived materials alone and combined with oxidized porous silicon microparticles (pSi-MP), a bioactive material known to release silicic acid and support mineralized tissue formation. Critical-size defects were created in four caudal vertebrae of Wistar rats and filled with nacre, pSi-MP, a nacre–pSi composite, or left empty. After 60 days, bone formation was assessed using micro-computed tomography and non-decalcified histology. Empty defects failed to regenerate, whereas nacre and pSi-MP individually promoted partial mineralized tissue deposition. The nacre–pSi composite produced the most extensive repair, showing near-complete defect bridging, higher bone mineral density, and seamless integration of particles within newly formed bone. No inflammation or adverse reactions were observed, and osteoid deposition occurred directly on material surfaces. These findings demonstrate that nacre-derived materials exert intrinsic osteogenic effects in vivo and that combining nacre with porous silicon yields a synergistic response that significantly enhances bone regeneration. The composite represents a promising candidate for future bone repair strategies. Full article

Purpose: Breast cancer (BC) incidence has been increasing rapidly in North Africa, including Morocco, yet evidence regarding modifiable lifestyle factors remains limited. This study aimed to assess the associations between physical activity, sedentary behavior, daily work habits, and BC risk among Moroccan women, addressing an important gap in regional data. Methods: We conducted a case–control study between 2019 and 2023, including 1400 histologically confirmed incident BC cases and 1400 matched controls. Physical activity was assessed across the lifespan, considering type, intensity, and duration. Associations with BC risk were estimated using adjusted odds ratios (aORs) and 95% confidence intervals (CIs). Results: Moderate physical activity was inversely associated with BC risk, showing a clear dose–response relationship. Compared with the lowest physical activity level, the highest quartile showed significantly lower odds of BC (aOR = 0.37 (95% CI: 0.29–0.47). Vigorous physical activity during young adulthood and mid-adulthood was similarly linked to reduced risk. Active daily habits, such as walking and regular stair climbing, were associated with lower odds, whereas frequent occupational fatigue and sweating were linked to increased risk. Conclusions: Our findings highlight a significant inverse association between physical activity and BC risk among Moroccan women. Notably, moderate PA and active daily habits like brisk walking are linked to lower odds of the disease. While these findings support the role of physical activity as an important factor associated with breast cancer prevention, the retrospective design of the study limits causal inference. Full article

Traditional hydroxyapatite materials are inherently stiff and brittle, limiting their applications. Flexible ultralong hydroxyapatite nanowires, characterized by nano-scale diameters and micrometer-scale lengths, offer a promising alternative as one-dimensional flexible building blocks for constructing high-performance biomimetic materials. Nature has evolved a variety of high-performance materials with hierarchically ordered structures assembled from nano-scale building blocks, which provide valuable insights into the design and ordered assembly of flexible nanofibers for building high-performance biomimetic materials. Currently, how to distill the structural design principles of natural materials to engineer flexible nanofibers into advanced high-performance biomimetic materials with excellent properties and multifunctions remains a frontier scientific challenge. In 2014, the authors’ research group reported for the first time the calcium oleate precursor solvothermal method for the synthesis of flexible ultralong hydroxyapatite nanowires and their applications. Since then, many soft functional materials and high-performance biomimetic materials have been designed and prepared using flexible ultralong hydroxyapatite nanowires, and their applications in various fields have been explored. These studies demonstrate the successful assembly of flexible ultralong hydroxyapatite nanowires into hierarchical biomimetic structures inspired by natural materials such as enamel, nacre, and bone, which exhibit enhanced mechanical properties, including improved strength, toughness, and flexibility, alongside multifunctional capabilities like thermal insulation and biomedical compatibility. These findings suggest that flexible ultralong hydroxyapatite nanowires provide a versatile platform for designing and constructing advanced biomimetic materials with promising applications in various fields. This review article aims to briefly review recent advances in this exciting and rapidly evolving research field. The synthetic methods, assembly strategies, properties, and applications of flexible ultralong hydroxyapatite nanowires and their derivative biomimetic materials are discussed, enlightening their structural design principles and potential applications. Finally, we propose future research directions and future perspectives in this exciting frontier research field. Full article

Grokhovskyite, CuCrS₂, was observed in small sulfide inclusions (up to 50–80 µm) in Ni-rich iron (kamacite) of the Uakit iron meteorite (IIAB) in the Republic of Buryatia, Russia. The grain sizes of this mineral are usually less than 5 μm, and the biggest detected crystals are 10 × 5 μm in size. It is commonly associated with daubréelite, troilite, schreibersite, and, sometimes, with carlsbergite and uakitite. Within inclusions, the mineral forms elongated splintered crystals, or, rarely, needle-shaped grains in daubréelite. The grokhovskyite-containing associations in the Uakit meteorite seem to form due to high-temperature (>1000 °C) separation of Fe-Cr sulfide liquid, which is locally enriched in Cu, from Fe-Ni metal melt. Physical and optical properties of grokhovskyite are quite similar to those of synthetic CuCrS₂: yellow–brown and non-transparent phase with metallic luster; Mohs hardness ≈ 4; gray to light gray color with yellow tint in reflected light; weak to medium bireflectance, anisotropy, and pleochroism; density (calc.) = 4.559 g/cm³. Grokhovskyite is structurally related to the Cr-containing disulfide minerals with general formula Me⁺CrS₂ (where Me⁺ = Na, Cu, Ag), including caswellsilverite, NaCrS₂; schöllhornite, Na_0.3CrS₂·H₂O; and cronusite, Ca_0.2CrS₂·2H₂O. Structural data were obtained for one grokhovskyite crystal using the EBSD technique. Fitting of the EBSD patterns for a synthetic α-CuCrS₂ model (trigonal R3m; a = 3.4794(8) Å; c = 18.702(4) Å; V = 196.08(10) ų; Z = 3) resulted in the parameter MAD = 0.57–1.16° (good fit). Analytical data for grokhovskyite (n = 36, in wt.%) are as follows: Cu—32.97; Cr—27.65; Fe—3.69; Ni—0.16; S—35.71; Na, Zn, V, Mn, and Co—below detection limit (<0.005 wt.%). The empirical formula is (Cu_0.930Cr_0.952Fe_0.118Ni_0.005)_2.005S_1.995; however, different concentrations of Fe are indicated in two individual grains of grokhovskyite (0.09–0.17 apfu). Such variations may be explained by Fe incorporation in the grokhovskyite structure according to the scheme ^IVCu⁺ + ^VICr³⁺ → ^IVFe²⁺ + ^VIFe²⁺. The three main bands (near 110, 250, and 310 cm⁻¹), which are common of synthetic CuCrS₂, were observed in the Raman spectra of grokhovskyite. Full article

The application of bioinspired nanocomposites in orthopedic implants marks a significant innovation in biomedical engineering, aimed at overcoming long-standing limitations of conventional implant materials. Traditional implants frequently suffer from poor osseointegration, mechanical mismatch with bone, and vulnerability to infection. Bioinspired nanocomposites, modeled after the hierarchical structures found in natural tissues such as bone and nacre, offer the potential to enhance mechanical performance, biological compatibility, and implant functionality. This study reviews and synthesizes current advancements in the design, fabrication, and functionalization of bioinspired nanocomposite materials for orthopedic use. Emphasis is placed on the integration of nanocrystalline hydroxyapatite (nHA), carbon nanotubes (CNTs), titanium dioxide (TiO₂) nanotubes, and other nanostructured coatings that mimic the extracellular matrix. Methods include comparative evaluations of mechanical properties, surface modifications for biocompatibility, and analyses of antibacterial efficacy through nano-topographical features. Bioinspired nanocomposites have been shown to improve osteoblast adhesion, proliferation, and differentiation, thereby enhancing osseointegration. Nanostructured coatings such as TiO₂ nanotubes increase surface hydrophilicity and corrosion resistance, supporting long-term implant stability. Mechanically, these composites offer high stiffness, superior wear resistance, and improved strength-to-weight ratios. Biomimetic combinations of hydroxyapatite, zirconia, and biopolymers have demonstrated effective load transfer and reduced stress shielding. Additionally, antibacterial functionality has been achieved via nanostructured surfaces that deter bacterial adhesion while remaining cytocompatible with host tissues. The integration of bioinspired nanocomposites into orthopedic implants provides a multifunctional platform for enhancing clinical outcomes. These materials not only replicate the mechanical and biological properties of native bone but also introduce new capabilities such as infection resistance and stimuli-responsive behavior. Despite these advancements, challenges including manufacturing scalability, long-term durability, and regulatory compliance remain. Continued interdisciplinary research is essential for translating these innovations from laboratory to clinical practice. Full article

Introduction: Breast cancer is the most common cancer among women worldwide, and its prognosis can be influenced by various factors, including geographic accessibility of healthcare services. This study describes the geographic distribution of breast cancer cases in the Casablanca-Settat region and evaluates the association between breast cancer stage at diagnosis, rural residence, and travel distance to healthcare facilities in the Casablanca-Settatregion. Methods: A retrospective hospital-based study was conducted on 2161 women diagnosed with breast cancer and admitted to Ibn Rochd University Hospital between December 2018 and January 2022. Patient residential addresses and healthcare facility locations were geocoded using Geographic Information Systems (GIS), and a straight-line distance was calculated from patients’ residences to the nearest Primary Healthcare Center (PHCC), Provincial Hospital Center (PHC), Regional Hospital Center (RHC), and University Hospital Center (UHC). Statistical analysis assessed associations between stage at diagnosis, rural/urban residence, and travel distance. Results: The overall mean distance to the UHC was 32.5 km (range: 0.19–164 km); 8.3 km (range: 0.02–83 km) to PHCs; and 1.25 km (range: 0.01–12.1 km) to PHCCs. Rural patients had longer distances to all facility types compared to urban patients. However, no significant association was found between cancer stage at diagnosis and rural residence or long travel distance to healthcare facilities (p > 0.05). Conclusions: The stage of breast cancer at diagnosis appears not to be influenced by travel distance to healthcare facilities or by rural residence. Full article

Pearl color is the primary determinant of its value, and the mantle donor tissue (saibo) used in pearl culture plays a critical role in color formation. To elucidate the molecular mechanisms underlying nacre color, we performed comparative transcriptomic analyses of saibo tissues from Sinohyriopsis cumingii displaying three representative phenotypes: white (W), purple (P), and golden (G). A total of 364 differentially expressed genes (DEGs) (102 upregulated and 162 downregulated genes) were identified in W vs. P. A total of 770 DEGs (467 upregulated and 303 downregulated genes) were identified in W vs. G. KEGG pathway analysis revealed significant differences in the expression of genes mainly involved in pigment-based and structural coloration, including amino sugar and nucleotide sugar metabolism (ko00520), cell adhesion molecules (ko04514), tyrosine metabolism (ko00350), ECM-receptor interaction (ko04512), and PI3K-Akt signaling pathway (ko04151). Subsequent integrative analyses across W vs. P and W vs. G groups identified 45 key regulatory genes, which were classified into four functional categories: extracellular matrix protein synthesis and biomineralization (e.g., chit, silkmaxin, bmp2/7, profilin, perlucin2), organic pigment metabolism (e.g., tyr, typ, dbh, bco2, gst5, ldlr, cpox, pks-like 1, pks15), metal ion metabolism and accumulation (e.g., hip-like, fcr1, ferritin 2), and epigenetic regulation (e.g., metK, mbd4/6, mettl24/27, alkbh6). Taken together, our findings reaffirm the complex nature of pearl coloration and reveal that structural coloration, pigment biosynthesis, and epigenetic modulation collectively shape nacre color formation, which paves the way for further functional elucidation of color-related genes and facilitates selective breeding practices in S. cumingii. Full article

Pearl color serves as the paramount criterion for quality assessment and commercial valuation in the global pearl industry. Freshwater nucleated pearls, which constitute 95% of global production, exhibit striking chromatic diversity. This study deciphers the chromogenic mechanisms of freshwater nucleated cultured pearls in Hyriopsis cumingii from Zhuji, China, through integrated spectroscopic (UV-vis-NIR and Raman), colorimetric (CIELAB), and trace-element (LA-ICP-MS) analyses. We identify polyene compounds as the primary organic chromophores, with C=C bond counts determining core hue: purple (12 C=C bonds), pink (11 C=C bonds), and white/orange (10 C=C bonds). Color expression is further modulated by nacre microstructure; densely aligned aragonite tablets enhance optical interference in purple pearls, whereas irregular tablet arrangements in pink and orange pearls promote diffuse scattering. Crucially, trace elements (Mn, Fe, Cu, Zn) contribute synergistically via metalloporphyrin formation (e.g., Mn-porphyrin in purple variants) and aragonite lattice substitutions. These findings reveal that pearl coloration arises from the interplay of biological factors (organic matrix), physical structure (nacre architecture), and chemical composition (trace elements), providing insights for quality enhancement and sustainable aquaculture practices. Full article

Drawing inspiration from the bionic nacre structure, graphene was incorporated into the epoxy solvent-borne adhesive to construct a laminated architecture. At the same time, ferrocene was employed as a catalyst to induce the in situ growth of carbon nanotubes (CNTs) under high-temperature conditions. This modification endowed the epoxy solvent-borne adhesive with not only high strength in atmospheric environments but also the capability to retain considerable mechanical performance at elevated temperatures. Experimental results demonstrated that when the graphene content in the epoxy solution fell within the range of 3.2–4%, the bonding strength exceeded 3 MPa within the temperature range of 1000–1300 °C. In particular, the adhesive exhibited excellent thermal shock resistance, with no degradation in strength observed after 15 thermal shock cycles at 1300 °C. Such exceptional performance was attributed to the formation of interlaminar CNTs generated after high-temperature treatment. Scanning electron microscopy (SEM) observations clearly revealed the laminated graphene sheets and in situ grown CNTs, confirming the feasibility of the strategy to enhance bonding efficacy by mimicking the nacre structure. This approach represented an innovative breakthrough for further research on the application of the “brick-and-mortar” structure in the bonding layer and the in situ growth of CNTs among lamellar graphene, while also providing detailed supporting data. Full article

Background: Ibrutinib has been associated with an increased risk of cardiovascular adverse events (CVAEs), including atrial fibrillation (AF), hypertension (HTN), heart failure (HF), and ventricular arrhythmias (VAs). However, baseline predictors of CVAEs remain poorly characterized. In this study, we sought to identify baseline patient characteristics associated with the occurrence of ibrutinib-related CVAEs, with particular emphasis on parameters linked to the renin–angiotensin system. Methods: We conducted a prospective, single-center cohort study of consecutive patients treated with ibrutinib for B-cell malignancy, with systematic assessment of a predefined panel of potential predictors of CVAEs at baseline (NCT03678337). These predictors included demographic and clinical variables, 16 circulating biomarkers related to inflammation, fibrosis, and neurohormonal activation, as well as nine echocardiographic parameters. The primary objective was to evaluate the association between baseline patient characteristics and the occurrence of CVAEs from ibrutinib initiation through the end of follow-up. The CVAE endpoint was defined as a composite of atrial fibrillation, new or worsening hypertension, new or worsening heart failure, and ventricular arrhythmias. Statistical analyses were performed using the Wilcoxon–Mann–Whitney test or Fisher’s exact test, with a p-value < 0.05 considered statistically significant. Results: Among the 25 patients included, 7 experienced a total of 9 CVAEs over a median follow-up of 672 days. Elevated baseline plasma renin levels (>1336.10 pg/mL) were significantly associated with CVAEs occurrence (57% vs. 11%, p = 0.032). Higher baseline plasma aldosterone levels (>488.95 pg/mL) were also observed in patients who developed CVAEs, although this association did not reach statistical significance (p = 0.058). Conclusions: Baseline plasma renin level was univariably associated with CVAEs occurrence, while plasma aldosterone levels were higher among patients with CVAEs but did not reach statistical significance. These findings provide preliminary insights into the mechanisms underlying ibrutinib-related cardiovascular toxicity, suggesting a potential role for the renin–angiotensin–aldosterone system. Confirmation of this hypothesis, however, will require larger, dedicated studies. Full article

Nacre, the iridescent inner layer of mollusk shells, has long been traditionally used in medicine. While we have previously demonstrated its anti-aging effects on muscle and skin, its impact on pancreatic dysfunction and glucose metabolism remains unclear. In this study, we aimed to isolate and identify an active component from nacre extract that improves glucose metabolism and to evaluate its potential to prevent or ameliorate pancreatic dysfunction and glucose metabolic abnormalities in a D-galactose-induced aging mouse model. A polysaccharide component was successfully isolated using a combination of reverse-phase and ion-exchange chromatography. Structural analyses revealed that it was primarily composed of glucose, mannose, and rhamnose, which together accounted for approximately 87% of the total monosaccharide content. Further characterization by FT-IR spectroscopy and MALDI-TOF-MS confirmed its identity as a neutral polysaccharide with glycosidic linkages and an estimated molecular weight of approximately 5000 Da. Intraperitoneal administration of this polysaccharide significantly improved glucose tolerance and prevented a decline in serum insulin levels in D-galactose-induced aging mice. Immunohistochemical analysis of pancreatic tissues revealed that the polysaccharide preserved insulin expression and suppressed the D-galactose-induced upregulation of cellular senescence and apoptosis markers. These findings suggest that this nacre-derived polysaccharide effectively mitigates pancreatic dysfunction and glucose metabolic dysfunction, indicating its potential as a natural therapeutic agent for age-related metabolic disorders. Full article

Although evidence suggests adiposity as a modifiable risk factor for postmenopausal breast cancer (BC), its association with premenopausal BC remains uncertain. This potential differential relationship for menopausal status has been insufficiently investigated in the Moroccan population due to limited data. This study aims to assess the relationship between various indicators of adiposity and the risk of BC among Moroccan women by menopausal status. A multicenter case-control study was conducted in Morocco between December 2019 and August 2023, including 1400 incident BC cases and 1400 matched controls. Detailed measures of adiposity and self-reported measures from different life stages were collected. Unconditional logistic regression analyses were conducted to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) for the association between body size indicators and the risk of BC, adjusting for a range of known risk factors for BC. Higher waist circumference (WC) and hip circumference (HC) were associated with an increased risk of BC in both pre- (p-trend < 0.001 for both WC and HC) and post-menopausal women (p-trend < 0.001 for WC, 0.002 for HC). Current body mass index (BMI) ≥30 kg/m² increased the risk of postmenopausal BC (p-trend = 0.012). Among postmenopausal women, higher weight at age 20 was positively associated with BC risk (p-trend < 0.001), while, weight at age 30 was significantly associated with increased BC risk in both pre- (p-trend = 0.008) and post-menopausal women (p-trend = 0.028). Interestingly, weight gain since age 20 was inversely associated with BC risk in postmenopausal women in the adjusted model (p-trend = 0.006). Young-adult BMI observed a significant increased trend with BC risk in both pre- (p-trend = 0.008) and post-menopausal women (p-trend < 0.001). In premenopausal women, larger body shape during childhood and early adulthood was positively associated with BC risk (p-trend = 0.01 and = 0.011, respectively). In postmenopausal women, larger childhood and adolescent body silhouettes were also associated with increased BC risk (p-trend = 0.045 and 0.047, respectively). These results suggest that anthropometric factors may have different associations with pre- and post-menopausal BC among Moroccan women. This underscores the importance of conducting large prospective studies to better understand these findings and explore their links to different molecular subtypes of BC. Full article

Nature’s principles offer design references for additive manufacturing (AM), enabling structures that achieve remarkable efficiency through hierarchical organization rather than material excess. This perspective article proposes a framework for integrating biomimetic principles into AM beyond morphological mimicry, focusing on functional adaptation and sustainability. By emulating biological systems like nacre, spider silk, and bone, AM utilizes traditional geometric replication to embed multifunctionality, responsiveness, and resource efficiency. Recent advances in the fields of 4D printing, soft robotics, and self-morphing systems demonstrate how time-dependent behaviors and environmental adaptability can be engineered through bioinspired material architectures. However, challenges in scalable fabrication, dynamic material programming, and true functional emulation (beyond morphological mimicry) necessitate interdisciplinary collaboration. In this context, the synthesis of biological intelligence with AM technologies offers sustainable, high-performance solutions for aerospace, biomedical, and smart infrastructure applications, once challenges related to material innovation and standardization are overcome. Full article

This study systematically investigates for the first time the effects of dual-site co-cultivation on spectral characteristics and trace element enrichment in marine-cultured Akoya pearls from Beihai, China. Akoya pearls were cultured over a one-year period, with the final 40-day stage designated as the terminal phase. During this period, two experimental groups of pearl oysters were established: Group Y remained in Beihai for continued local cultivation and harvest, while Group B was transferred to Weihai, Shandong Province, for terminal-stage farming under different thermal conditions. A series of comparative analyses were performed using Fourier-transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, Raman spectroscopy, X-ray fluorescence (XRF), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The FTIR results revealed distinct differences between the two groups in the distribution of amide and polysaccharide functional groups, particularly around 1643 cm⁻¹ and 1100 cm⁻¹. The UV-Vis spectra of Group B displayed characteristic absorption bands at 430 nm and 460 nm, associated with the organic matrix of the nacre. Raman spectroscopy further indicated a higher abundance of organic-related vibrational features in Group B. Additionally, both XRF and LA-ICP-MS analyses consistently showed significant differences in the concentrations and distributions of trace elements, particularly copper (Cu), cobalt (Co), and zinc (Zn). The findings demonstrate that the dual-site co-cultivation mode significantly impacts both the organic composition and trace element enrichment patterns in seawater Akoya pearls. This research provides valuable references for optimizing environmental parameters in pearl cultivation processes. Full article