A phase II study of pembrolizumab plus carboplatin in BRCA-related metastatic breast cancer (PEMBRACA).

BACKGROUND: BRCA1/2-related metastatic breast cancers (mBC) are sensitive to DNA-damage agents and show high tumor-infiltrated lymphocytes. We hypothesized that the association between pembrolizumab and carboplatin could be active in BRCA-related mBC. PATIENTS AND METHODS: In this phase II Simon's design multicenter single-arm study, BRCA1/2-related mBC patients received carboplatin at area under the curve 6 every 3 weeks for six courses associated with 200 mg pembrolizumab every 3 weeks until disease progression or unacceptable toxicity. The primary aim at first stage was overall response rate (ORR) ≥70%. Disease control rate (DCR), time to progression (TTP), duration of response (DOR), and overall survival (OS) were the secondary aims. RESULTS: Among 22 patients enrolled at the first stage, 5 BRCA1 and 17 BRCA2, 16 (76%) were luminal tumors and 6 (24%) triple-negative BC (TNBC). In 21 patients, ORR and DCR were 43% and 76% (47% and 87% in luminal, 33% and 50% in TNBC), respectively. TTP was 7.1 months, DOR was 6.3 months, and median OS was not reached. Grade ≥3 adverse events (AEs) or serious AEs occurred in 5/22 patients (22.7%). Since the primary aim was not met, the study was terminated at the first stage. CONCLUSIONS: Although the primary aim was not reached, data on efficacy and safety of pembrolizumab plus carboplatin in first-line visceral disease BRCA-related luminal mBC were provided and they need to be further investigated.

Background rates of 41 adverse events of special interest for COVID-19 vaccines in 10 European healthcare databases - an ACCESS cohort study.

BACKGROUND: In May 2020, the ACCESS (The vACCine covid-19 monitoring readinESS) project was launched to prepare real-world monitoring of COVID-19 vaccines. Within this project, this study aimed to generate background incidence rates of 41 adverse events of special interest (AESI) to contextualize potential safety signals detected following administration of COVID-19 vaccines. METHODS: A dynamic cohort study was conducted using a distributed data network of 10 healthcare databases from 7 European countries (Italy, Spain, Denmark, The Netherlands, Germany, France and United Kingdom) over the period 2017 to 2020. A common protocol (EUPAS37273), common data model, and common analytics programs were applied for syntactic, semantic and analytical harmonization. Incidence rates (IR) for each AESI and each database were calculated by age and sex by dividing the number of incident cases by the total person-time at risk. Age-standardized rates were pooled using random effect models according to the provenance of the events. FINDINGS: A total number of 63,456,074 individuals were included in the study, contributing to 211.7 million person-years. A clear age pattern was observed for most AESIs, rates also varied by provenance of disease diagnosis (primary care, specialist care). Thrombosis with thrombocytopenia rates were extremely low ranging from 0.06 to 4.53/100,000 person-years for cerebral venous sinus thrombosis (CVST) with thrombocytopenia (TP) and mixed venous and arterial thrombosis with TP, respectively. INTERPRETATION: Given the nature of the AESIs and the setting (general practitioners or hospital-based databases or both), background rates from databases that show the highest level of completeness (primary care and specialist care) should be preferred, others can be used for sensitivity. The study was designed to ensure representativeness to the European population and generalizability of the background incidence rates. FUNDING: The project has received support from the European Medicines Agency under the Framework service contract nr EMA/2018/28/PE.

GII.4 human norovirus and G8P[1] bovine-like rotavirus in oysters (Crassostrea gigas) from Argentina.

Bivalve mollusks have been widely recognized as an important source of foodborne virus. The aim of this work was to determine the presence of norovirus (NoV) and rotavirus (RVA) in Pacific cupped oyster (Crassostrea gigas) from Buenos Aires, Argentina. A total of 88 oyster were processed. 7% of pooled samples resulted positive for NoV GII by RT-qPCR. The nucleotide analysis showed that it was closely related to GII.4/Sydney. Regarding RVA, 21% were positive by RT-qPCR targeting the NSP3 gene. RVA from one pool was isolated in cell culture and infective viral particles were evidenced by immunofluorescence. The genotype constellation of RVA/Oyster-wt/Crassostrea gigas_BA/2015/G8P[1] isolated strain was G8-P[1]-I2-R2-C2-M2-A3-N2-T6-E2-H3, which has a bovine-like genome backbone. Notably, RVA possesses an E2 genotype which is different from the characteristic E12 genotype of RVA circulating in animal species from South America. Our findings evidence not only the presence of enteric viruses in oysters from Argentina, but most important the viability of RVA. This result pose the need to implement surveillance programs to prevent potential foodborne viral outbreaks due to the consumption of contaminated shellfish.

Two-month stop in mammographic screening significantly impacts on breast cancer stage at diagnosis and upfront treatment in the COVID era.

INTRODUCTION: The present analysis aims to evaluate the consequences of a 2-month interruption of mammographic screening on breast cancer (BC) stage at diagnosis and upfront treatments in a region of Northern Italy highly affected by the severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) virus. METHODS: This retrospective single-institution analysis compared the clinical pathological characteristics of BC diagnosed between May 2020 and July 2020, after a 2-month screening interruption, with BC diagnosed in the same trimester of 2019 when mammographic screening was regularly carried out. RESULTS: The 2-month stop in mammographic screening produced a significant decrease in in situ BC diagnosis (-10.4%) and an increase in node-positive (+11.2%) and stage III BC (+10.3%). A major impact was on the subgroup of patients with BC at high proliferation rates. Among these, the rate of node-positive BC increased by 18.5% and stage III by 11.4%. In the subgroup of patients with low proliferation rates, a 9.3% increase in stage III tumors was observed, although node-positive tumors remained stable. Despite screening interruption, procedures to establish a definitive diagnosis and treatment start were subsequently carried out without delay. CONCLUSION: Our data showed an increase in node-positive and stage III BC after a 2-month stop in BC screening. These findings support recommendations for a quick restoration of BC screening at full capacity, with adequate prioritization strategies to mitigate harm and meet infection prevention requirements.

The effects of human sera conditioned by high-intensity exercise sessions and training on the tumorigenic potential of cancer cells

Purpose There is growing evidence of an association between physical activity and a reduced risk of cancer and cancer recurrence. The aim of this study was to assess the effects of exercise-conditioned human serum (HS) effects on the proliferative and tumorigenic potential of triple-negative breast cancer (TNBC) and prostate cancer (PC) cells. Moreover, modulated mechanisms and several physiological factors that can predict exercise effects were investigated. Methods Thirty healthy sedentary subjects were recruited for the study. The subjects performed two high-intensity endurance cycling (HIEC) sessions before and after a nine-week period of high-intensity interval training (HIIT). Cell tumorigenic capacity affected by HS collected before (t0), immediately after (t1), 4 h (t2), and 24 h (t3) after the HIEC sessions was evaluated by in vitro three-dimensional colony formation. The modulation of molecular pathways was analyzed by western blotting and qPCR in TNBC and PC cells, and in TNBC xenografts in exercised mice. Results All of the HIEC-conditioned HS (t1, t2, and t3) markedly impacted the proliferative and the microtumor-forming capacity of both TNBC and PC cell lines, while the HS collected from the subjects at rest did not. Modulation of the Hippo and Wnt/β-catenin pathways by HIEC-conditioned HS before and after the period of HIIT was shown. Multiple linear regression analysis showed relationships between the effects of HIEC-conditioned HS in PC cells, lactate threshold and VO2max. Conclusions These results highlight the potential of HIEC bouts in tumor progression control and the importance of optimizing an approach to identify physiological predictors of the effects of acute exercise in tertiary cancer prevention (AU)

The effects of human sera conditioned by high-intensity exercise sessions and training on the tumorigenic potential of cancer cells.

PURPOSE: There is growing evidence of an association between physical activity and a reduced risk of cancer and cancer recurrence. The aim of this study was to assess the effects of exercise-conditioned human serum (HS) effects on the proliferative and tumorigenic potential of triple-negative breast cancer (TNBC) and prostate cancer (PC) cells. Moreover, modulated mechanisms and several physiological factors that can predict exercise effects were investigated. METHODS: Thirty healthy sedentary subjects were recruited for the study. The subjects performed two high-intensity endurance cycling (HIEC) sessions before and after a nine-week period of high-intensity interval training (HIIT). Cell tumorigenic capacity affected by HS collected before (t0), immediately after (t1), 4 h (t2), and 24 h (t3) after the HIEC sessions was evaluated by in vitro three-dimensional colony formation. The modulation of molecular pathways was analyzed by western blotting and qPCR in TNBC and PC cells, and in TNBC xenografts in exercised mice. RESULTS: All of the HIEC-conditioned HS (t1, t2, and t3) markedly impacted the proliferative and the microtumor-forming capacity of both TNBC and PC cell lines, while the HS collected from the subjects at rest did not. Modulation of the Hippo and Wnt/ß-catenin pathways by HIEC-conditioned HS before and after the period of HIIT was shown. Multiple linear regression analysis showed relationships between the effects of HIEC-conditioned HS in PC cells, lactate threshold and VO2max. CONCLUSIONS: These results highlight the potential of HIEC bouts in tumor progression control and the importance of optimizing an approach to identify physiological predictors of the effects of acute exercise in tertiary cancer prevention.

Correction to: Implementation and impact of pediatric antimicrobial stewardship programs: a systematic scoping review.

The original article [1] contains an error in Fig. 1 whereby the number of selected articles of the first box is incorrect.

Implementation and impact of pediatric antimicrobial stewardship programs: a systematic scoping review.

Background: Antibiotics are the most common medicines prescribed to children in hospitals and the community, with a high proportion of potentially inappropriate use. Antibiotic misuse increases the risk of toxicity, raises healthcare costs, and selection of resistance. The primary aim of this systematic review is to summarize the current state of evidence of the implementation and outcomes of pediatric antimicrobial stewardship programs (ASPs) globally. Methods: MEDLINE, Embase and Cochrane Library databases were systematically searched to identify studies reporting on ASP in children aged 0-18 years and conducted in outpatient or in-hospital settings. Three investigators independently reviewed identified articles for inclusion and extracted relevant data. Results: Of the 41,916 studies screened, 113 were eligible for inclusion in this study. Most of the studies originated in the USA (52.2%), while a minority were conducted in Europe (24.7%) or Asia (17.7%). Seventy-four (65.5%) studies used a before-and-after design, and sixteen (14.1%) were randomized trials. The majority (81.4%) described in-hospital ASPs with half of interventions in mixed pediatric wards and ten (8.8%) in emergency departments. Only sixteen (14.1%) studies focused on the costs of ASPs. Almost all the studies (79.6%) showed a significant reduction in inappropriate prescriptions. Compliance after ASP implementation increased. Sixteen of the included studies quantified cost savings related to the intervention with most of the decreases due to lower rates of drug administration. Seven studies showed an increased susceptibility of the bacteria analysed with a decrease in extended spectrum beta-lactamase producers E. coli and K. pneumoniae; a reduction in the rate of P. aeruginosa carbapenem resistance subsequent to an observed reduction in the rate of antimicrobial days of therapy; and, in two studies set in outpatient setting, an increase in erythromycin-sensitive S. pyogenes following a reduction in the use of macrolides. Conclusions: Pediatric ASPs have a significant impact on the reduction of targeted and empiric antibiotic use, healthcare costs, and antimicrobial resistance in both inpatient and outpatient settings. Pediatric ASPs are now widely implemented in the USA, but considerable further adaptation is required to facilitate their uptake in Europe, Asia, Latin America and Africa.

Environmental impact of biogenic silver nanoparticles in soil and aquatic organisms.

Synthetic silver nanoparticles (AgNPs) are being extensively used in our daily lives; however, they may also pose a risk to public health and environment. Nowadays, biological AgNPs are considered an excellent alternative, since their synthesis occurs by a green technology of low cost and easy scaling. However, studies with these biological nanomaterials (NM) are still limited. Thus, a more careful assessment of their industrial application, economic feasibility and ecotoxicological impacts is crucial. The aim of this study was to investigate the effects of different concentrations of mangrove fungus Aspergillus tubingensis AgNPs on the aerobic heterotrophs soil microorganisms, rice seeds (Oryza sativa) and zebrafish (Danio rerio). Biogenic AgNPs were less harmful for soil microbiota compared to AgNO3. On rice seeds, the AgNPs displayed a dose-dependent inhibitory effect on germination and their subsequent growth and development. The percentage of inhibition of rice seed germination was 30, 69 and 80% for 0.01, 0.1 and 0.5 mM AgNPs, respectively. After 24 h of AgNPs exposition at a limit concentration of 0.2 mM, it did not induce mortality of the zebrafish D. rerio. Overall, A. tubingensis AgNPs can be considered as a suitable alternative to synthetic nanoparticles.

Associations between specific plasma ceramides and severity of coronary-artery stenosis assessed by coronary angiography.

AIM: Recent prospective studies have identified distinct plasma ceramides as strong predictors of major adverse cardiovascular events in patients with established or suspected coronary artery disease (CAD). Currently, it is uncertain whether higher levels of distinct plasma ceramides are associated with greater angiographic severity of coronary-artery stenoses in this patient population. METHODS: We measured six previously identified high-risk plasma ceramide species [Cer(d18:1/16:0), Cer(d18:1/18:0), Cer(d18:1/20:0), Cer(d18:1/22:0), Cer(d18:1/24:0) and Cer(d18:1/24:1)] in 167 consecutive patients with established or suspected CAD, who underwent urgent or elective coronary angiography. RESULTS: Approximately 77% of patients had a significant stenosis (≥50%) in one or more of the main coronary arteries, the majority of whom (∼60%) had a significant stenosis in the left anterior descending (LAD) artery. Of the six measured plasma ceramides, higher levels of plasma Cer(d18:1/20:0) (adjusted-odds ratio 1.39, 95%CI 1.0-1.99), Cer(d18:1/22:0) (adjusted-odds ratio 1.57, 95%CI 1.08-2.29) and Cer(d18:1/24:0) (adjusted-odds ratio 1.59, 95%CI 1.08-2.32) were significantly associated with the presence of LAD stenosis≥50%, after adjustment for age, sex, smoking, pre-existing CAD, hypertension, diabetes, dyslipidaemia, lipid-lowering therapy, estimated glomerular filtration rate and plasma C-reactive protein levels. Almost identical results were found even after excluding patients (n=15) with acute ST-elevation myocardial infarction. Similar results were also found when patients were categorized according to the Gensini severity score. CONCLUSION: Our cross-sectional study shows for the first time that higher levels of specific plasma ceramides are independently associated with a greater severity of coronary-artery stenoses in the LAD artery in patients who had suspected or established CAD.

Reduction of fibrillar strain-rate sensitivity in steroid-induced osteoporosis linked to changes in mineralized fibrillar nanostructure.

As bone is used in a dynamic mechanical environment, understanding the structural origins of its time-dependent mechanical behaviour - and the alterations in metabolic bone disease - is of interest. However, at the scale of the mineralized fibrillar matrix (nanometre-level), the nature of the strain-rate dependent mechanics is incompletely understood. Here, we investigate the fibrillar- and mineral-deformation behaviour in a murine model of Cushing's syndrome, used to understand steroid induced osteoporosis, using synchrotron small- and wide-angle scattering/diffraction combined with in situ tensile testing at three strain rates ranging from 10-4 to 10-1 s-1. We find that the effective fibril- and mineral-modulus and fibrillar-reorientation show no significant increase with strain-rate in osteoporotic bone, but increase significantly in normal (wild-type) bone. By applying a fibril-lamellar two-level structural model of bone matrix deformation to fit the results, we obtain indications that altered collagen-mineral interactions at the nanoscale - along with altered fibrillar orientation distributions - may be the underlying reason for this altered strain-rate sensitivity. Our results suggest that an altered strain-rate sensitivity of the bone matrix in osteoporosis may be one of the contributing factors to reduced mechanical competence in such metabolic bone disorders, and that increasing this sensitivity may improve biomechanical performance.

Environmental impact of biogenic silver nanoparticles in soil and aquatic organisms

Synthetic silver nanoparticles (AgNPs) are being extensively used in our daily lives; however, they may also pose a risk to public health and environment. Nowadays, biological AgNPs are considered an excellent alternative, since their synthesis occurs by a green technology of low cost and easy scaling. However, studies with these biological nanomaterials (NM) are still limited. Thus, a more careful assessment of their industrial application, economic feasibility and ecotoxicological impacts is crucial. The aim of this study was to investigate the effects of different concentrations of mangrove fungus Aspergillus tubingensis AgNPs on the aerobic heterotrophs soil microorganisms, rice seeds (Oryza sativa) and zebrafish (Danio rerio). Biogenic AgNPs were less harmful for soil microbiota compared to AgNO3. On rice seeds, the AgNPs displayed a dose-dependent inhibitory effect on germination and their subsequent growth and development. The percentage of inhibition of rice seed germination was 30, 69 and 80% for 0.01, 0.1 and 0.5 mM AgNPs, respectively. After 24h of AgNPs exposition at a limit concentration of 0.2 mM, it did not induce mortality of the zebrafish D. rerio. Overall, A. tubingensis AgNPs can be considered as a suitable alternative to synthetic nanoparticles.

Environmental impact of biogenic silver nanoparticles in soil and aquatic organisms

Synthetic silver nanoparticles (AgNPs) are being extensively used in our daily lives; however, they may also pose a risk to public health and environment. Nowadays, biological AgNPs are considered an excellent alternative, since their synthesis occurs by a green technology of low cost and easy scaling. However, studies with these biological nanomaterials (NM) are still limited. Thus, a more careful assessment of their industrial application, economic feasibility and ecotoxicological impacts is crucial. The aim of this study was to investigate the effects of different concentrations of mangrove fungus Aspergillus tubingensis AgNPs on the aerobic heterotrophs soil microorganisms, rice seeds (Oryza sativa) and zebrafish (Danio rerio). Biogenic AgNPs were less harmful for soil microbiota compared to AgNO3. On rice seeds, the AgNPs displayed a dose-dependent inhibitory effect on germination and their subsequent growth and development. The percentage of inhibition of rice seed germination was 30, 69 and 80% for 0.01, 0.1 and 0.5 mM AgNPs, respectively. After 24h of AgNPs exposition at a limit concentration of 0.2 mM, it did not induce mortality of the zebrafish D. rerio. Overall, A. tubingensis AgNPs can be considered as a suitable alternative to synthetic nanoparticles.

Antibiotic prescriptions in acute otitis media and pharyngitis in Italian pediatric outpatients.

BACKGROUND: Acute otitis media (AOM) and pharyngitis are very common infections in children and adolescents. Italy is one of the European countries with the highest rate of antibiotic prescriptions. The aim of this study is to describe first-line treatment approaches for AOM and pharyngitis in primary care settings in Italy over six years, including the prevalence of 'wait and see' for AOM, where prescription of antibiotics is delayed 48 h from presentation, and differences in prescribing for pharyngitis when diagnostic tests are used. METHODS: The study is a secondary data analysis using Pedianet, a database including data at outpatient level from children aged 0-14 in Italy. Prescriptions per antibiotic group, per age group and per calendar year were described as percentages. "Wait and see" approach rate was described for AOM and pharyngitis prescriptions were further grouped according to the diagnostic test performed and test results. RESULTS: We identified 120,338 children followed by 125 family pediatricians between January 2010 and December 2015 for a total of 923,780 person-years of follow-up. Among them 30,394 (mean age 44 months) had at least one AOM diagnosis (n = 54,943) and 52,341 (mean age 5 years) had at least one pharyngitis diagnosis (n = 126,098). 82.5% of AOM diagnoses were treated with an antibiotic within 48 h (mainly amoxicillin and amoxicillin/clavulanate) and the "wait and see" approach was adopted only in 17.5% of cases. The trend over time shows an increase in broad spectrum antibiotic prescriptions in the last year (2015). 79,620 (63%) cases of pharyngitis were treated and among GABHS pharyngitis confirmed by rapid test 56% were treated with amoxicillin. The ones not test confirmed were treated mainly with broad spectrum antibiotics. CONCLUSIONS: Despite guidance to use the 'wait and see' approach in the age group analyzed, this strategy is not often used for AOM, as previously noted in other studies in hospital settings. Broad-spectrum antibiotic prescription was more frequent when pharyngitis was not confirmed by rapid test, in keeping with evidence from other studies that diagnostic uncertainty leads to overuse of antibiotics.

Bone matrix development in steroid-induced osteoporosis is associated with a consistently reduced fibrillar stiffness linked to altered bone mineral quality.

Glucocorticoid-induced osteoporosis (GIOP) is a major secondary form of osteoporosis, with the fracture risk significantly elevated - at similar levels of bone mineral density - in patients taking glucocorticoids compared with non-users. The adverse bone structural changes at multiple hierarchical levels in GIOP, and their mechanistic consequences leading to reduced load-bearing capacity, are not clearly understood. Here we combine experimental X-ray nanoscale mechanical imaging with analytical modelling of the bone matrix mechanics to determine mechanisms causing bone material quality deterioration during development of GIOP. In situ synchrotron small-angle X-ray diffraction combined with tensile testing was used to measure nanoscale deformation mechanisms in a murine model of GIOP, due to a corticotrophin-releasing hormone promoter mutation, at multiple ages (8-, 12-, 24- and 36 weeks), complemented by quantitative micro-computed tomography and backscattered electron imaging to determine mineral concentrations. We develop a two-level hierarchical model of the bone matrix (mineralized fibril and lamella) to predict fibrillar mechanical response as a function of architectural parameters of the mineralized matrix. The fibrillar elastic modulus of GIOP-bone is lower than healthy bone throughout development, and nearly constant in time, in contrast to the progressively increasing stiffness in healthy bone. The lower mineral platelet aspect ratio value for GIOP compared to healthy bone in the multiscale model can explain the fibrillar deformation. Consistent with this result, independent measurement of mineral platelet lengths from wide-angle X-ray diffraction finds a shorter mineral platelet length in GIOP. Our results show how lowered mineralization combined with altered mineral nanostructure in GIOP leads to lowered mechanical competence. SIGNIFICANCE STATEMENT: Increased fragility in musculoskeletal disorders like osteoporosis are believed to arise due to alterations in bone structure at multiple length-scales from the organ down to the supramolecular-level, where collagen molecules and elongated mineral nanoparticles form stiff fibrils. However, the nature of these molecular-level alterations are not known. Here we used X-ray scattering to determine both how bone fibrils deform in secondary osteoporosis, as well as how the fibril orientation and mineral nanoparticle structure changes. We found that osteoporotic fibrils become less stiff both because the mineral nanoparticles became shorter and less efficient at transferring load from collagen, and because the fibrils are more randomly oriented. These results will help in the design of new composite musculoskeletal implants for bone repair.

Prognostic impact of interval breast cancer detection in women with pT1a N0M0 breast cancer with HER2-positive status: Results from a multicentre population-based cancer registry study.

BACKGROUND: Although human epidermal growth factor receptor 2 (HER2) overexpression is associated with poor prognosis, patients (pts) with pT1a N0M0 breast cancers (BCs) have an excellent outcome across all subtypes. Interval cancers (ICs) have poorer survival than screen-detected (SD) tumours, and an association has been reported between ICs and HER2 overexpression. We aimed to determine, in a general population of pT1a N0M0 BCs with known screening status, whether HER2-positive ICs have a poorer outcome than HER2-positive SD cancers. METHODS: We evaluated all incident pT1a N0M0 BCs (n = 874) collected in the Emilia-Romagna region (Italy) from 2003 to 2009 and diagnosed in women aged 50-69. Pts unexposed to screening, with unknown HER2 status and/or treated with adjuvant trastuzumab were excluded from analysis. RESULTS: Sixty-one percent of the BCs were SD, whereas 19% were ICs. BCs with high histologic grade, hormone receptor-negative or HER2-positive status (odds ratio=1.7; 95% confidence interval [CI]: 1.1-2.7) were more likely ICs. Median follow-up was 115 months. The 10-year invasive disease-free survival (iDFS) for HER2-positive ICs was lower than that for HER2-positive SD cancers: 75.0% (95% CI: 55.5%-94.5%) versus 93.8% (95% CI: 86.5%-100%). An interaction between ICs and HER2-positive status was found for poorer iDFS after adjusting for prognostic variables (HR = 5.3; 95% CI: 1.6-16.7). CONCLUSIONS: IC detection may identify pts with HER2-positive pT1a N0M0 tumours in whom the rate of recurrence justifies consideration for conventional, anti-HER2, adjuvant treatment.

Towards in situ determination of 3D strain and reorientation in the interpenetrating nanofibre networks of cuticle.

Determining the in situ 3D nano- and microscale strain and reorientation fields in hierarchical nanocomposite materials is technically very challenging. Such a determination is important to understand the mechanisms enabling their functional optimization. An example of functional specialization to high dynamic mechanical resistance is the crustacean stomatopod cuticle. Here we develop a new 3D X-ray nanostrain reconstruction method combining analytical modelling of the diffraction signal, fibre-composite theory and in situ deformation, to determine the hitherto unknown nano- and microscale deformation mechanisms in stomatopod tergite cuticle. Stomatopod cuticle at the nanoscale consists of mineralized chitin fibres and calcified protein matrix, which form (at the microscale) plywood (Bouligand) layers with interpenetrating pore-canal fibres. We uncover anisotropic deformation patterns inside Bouligand lamellae, accompanied by load-induced fibre reorientation and pore-canal fibre compression. Lamination theory was used to decouple in-plane fibre reorientation from diffraction intensity changes induced by 3D lamellae tilting. Our method enables separation of deformation dynamics at multiple hierarchical levels, a critical consideration in the cooperative mechanics characteristic of biological and bioinspired materials. The nanostrain reconstruction technique is general, depending only on molecular-level fibre symmetry and can be applied to the in situ dynamics of advanced nanostructured materials with 3D hierarchical design.

Staggered Fibrils and Damageable Interfaces Lead Concurrently and Independently to Hysteretic Energy Absorption and Inhomogeneous Strain Fields in Cyclically Loaded Antler Bone.

The high toughness and work to fracture of hierarchical composites, like antler bone, involve structural mechanisms at the molecular, nano-, and micro scales, which are not completely explored. A key characteristic of the high energy absorption of such materials is the large hysteresis during cyclic loading, but its origin remains unknown. In situ synchrotron X-ray diffraction tests during tensile loading of antler bone showed heterogeneous fibrillar deformation and hysteresis. To explain the origin of these mechanisms from the nanostructure of antler bone, here we develop a class of finite-element fibril models whose predictions are compared to experimental data across a range of potential composite architectures. We demonstrate that the key structural motif enabling a match to experimental data is an axially staggered arrangement of stiff mineralized collagen fibrils coupled with weak, damageable interfibrillar interfaces.