Coarse-grained modeling and dynamics tracking of nanoparticles diffusion in human gut mucus

The gastrointestinal (GI) tract's mucus layer serves as a critical barrier and a mediator in drug nanoparticle delivery. The mucus layer's diverse molecular structures and spatial complexity complicates the mechanistic study of the diffusion dynamics of particulate materials. In response, we developed a bi-component coarse-grained mucus model, specifically tailored for the colorectal cancer environment, that contained the two most abundant glycoproteins in GI mucus: Muc2 and Muc5AC. This model demonstrated the effects of molecular composition and concentration on mucus pore size, a key determinant in the permeability of nanoparticles. Using this computational model, we investigated the diffusion rate of polyethylene glycol (PEG) coated nanoparticles, a widely used muco-penetrating nanoparticle. We validated our model with experimentally characterized mucus pore sizes and the diffusional coefficients of PEG-coated nanoparticles in the mucus collected from cultured human colorectal goblet cells. Machine learning fingerprints were then employed to provide a mechanistic understanding of nanoparticle diffusional behavior. We found that larger nanoparticles tended to be trapped in mucus over longer durations but exhibited more ballistic diffusion over shorter time spans. Through these discoveries, our model provides a promising platform to study pharmacokinetics in the GI mucus layer.

Paradigm shift towards emergency cholecystectomy: one site experience of the Chole-QuiC process

INTRODUCTION

Substantial evidence exists for the superiority of emergency over delayed cholecystectomy for gallstone disease during primary admission. Despite this, emergency surgery rates in the UK remain low compared with other developed countries, with great variation in care across the nation. We aimed to describe the local paradigm shift towards emergency surgery and investigate outcomes.

METHODS

This is a prospective observational study examining patients enrolled onto an emergency cholecystectomy pathway, following the hospital's subscription to the Royal College of Surgeons of England's Cholecystectomy Quality Improvement Collaborative (Chole-QuIC), between 1 December 2021 and 31 January 2023. Multivariate logistical regression models were used to identify patient and hospital factors associated with postoperative outcomes.

RESULTS

Of the 307 suitable acute admissions, 261 (85%) had an emergency cholecystectomy, compared with 5% preceding the Chole-QuIC interventions. Waiting time dropped from 67 to 5 days. A total of 208 (79.7%) patients were primary presentations, 92 (35.2%) were classed Tokyo grade 2 and 142 (54.4%) were obese. A total of 23 (8.8%) patients underwent preoperative endoscopic retrograde cholangiopancreatography, and 26 (10%) patients had a subtotal cholecystectomy. Favourable outcomes (Clavien Dindo ≥3) were observed in first presentations (odds ratio (OR) 0.35; p=0.042) and for operation times within 7 days (OR 0.32; p=0.037), with worse outcomes in BMI ≥35 (OR 3.32; p=0.005) and operation time >7 days (OR 3.11; p=0.037).

CONCLUSION

A paradigm shift towards emergency cholecystectomy benefits both the patient and the service. Positive outcomes are apparent for early operation in patients presenting for the first time and recurrent attendees, with early operation (<7 days) providing the most favourable outcome in a select patient group.

Design and Characterization of Model Systems that Promote and Disrupt Transparency of Vertebrate Crystallins In Vitro

Positioned within the eye, the lens supports vision by transmitting and focusing light onto the retina. As an adaptive glassy material, the lens is constituted primarily by densely-packed, polydisperse crystallin proteins that organize to resist aggregation and crystallization at high volume fractions, yet the details of how crystallins coordinate with one another to template and maintain this transparent microstructure remain unclear. The role of individual crystallin subtypes (α, β, and γ) and paired subtype compositions, including how they experience and resist crowding-induced turbidity in solution, is explored using combinations of spectrophotometry, hard-sphere simulations, and surface pressure measurements. After assaying crystallin combinations, β-crystallins emerged as a principal component in all mixtures that enabled dense fluid-like packing and short-range order necessary for transparency. These findings helped inform the design of lens-like hydrogel systems, which are used to monitor and manipulate the loss of transparency under different crowding conditions. When taken together, the findings illustrate the design and characterization of adaptive materials made from lens proteins that can be used to better understand mechanisms regulating transparency.

Replica symmetry broken states of some glass models

We have studied in detail the M-p balanced spin-glass model, especially the case p=4. These types of model have relevance to structural glasses. The models possess two kinds of broken replica states; those with one-step replica symmetry breaking (1RSB) and those with full replica symmetry breaking (FRSB). To determine which arises requires studying the Landau expansion to quintic order. There are nine quintic-order coefficients, and five quartic-order coefficients, whose values we determine for this model. We show that it is only for 2≤M<2.4714⋯ that the transition at mean-field level is to a state with FRSB, while for larger M values there is either a continuous transition to a state with 1RSB (when M≤3) or a discontinuous transition for M>3. The Gardner transition from a 1RSB state at low temperatures to a state with FRSB also requires the Landau expansion to be taken to quintic order. Our result for the form of FRSB in the Gardner phase is similar to that found when 2≤M<2.4714⋯, but differs from that given in the early paper of Gross et al. [Phys. Rev. Lett. 55, 304 (1985)0031-900710.1103/PhysRevLett.55.304]. Finally we discuss the effects of fluctuations on our mean-field solutions using the scheme of Höller and Read [Phys. Rev. E 101, 042114 (2020)2470-004510.1103/PhysRevE.101.042114] and argue that such fluctuations will remove both the continuous 1RSB transition and discontinuous 1RSB transitions when 8>d≥6 leaving just the FRSB continuous transition. We suggest values for M and p which might be used in simulations to confirm whether fluctuation corrections do indeed remove the 1RSB transitions.

Controlling biofilm transport with porous metamaterials designed with Bayesian learning

Biofilm growth and transport in confined systems frequently occur in natural and engineered systems. Designing customizable engineered porous materials for controllable biofilm transportation properties could significantly improve the rapid utilization of biofilms as engineered living materials for applications in pollution alleviation, material self-healing, energy production, and many more. We combine Bayesian optimization (BO) and individual-based modeling to conduct design optimizations for maximizing different porous materials' (PM) biofilm transportation capability. We first characterize the acquisition function in BO for designing 2-dimensional porous membranes. We use the expected improvement acquisition function for designing lattice metamaterials (LM) and 3-dimensional porous media (3DPM). We find that BO is 92.89% more efficient than the uniform grid search method for LM and 223.04% more efficient for 3DPM. For all three types of structures, the selected characterization simulation tests are in good agreement with the design spaces approximated with Gaussian process regression. All the extracted optimal designs exhibit better biofilm growth and transportability than unconfined space without substrates. Our comparison study shows that PM stimulates biofilm growth by taking up volumetric space and pushing biofilms' upward growth, as evidenced by a 20% increase in bacteria cell numbers in unconfined space compared to porous materials, and 128% more bacteria cells in the target growth region for PM-induced biofilm growth compared with unconfined growth. Our work provides deeper insights into the design of substrates to tune biofilm growth, analyzing the optimization process and characterizing the design space, and understanding biophysical mechanisms governing the growth of biofilms.

Elucidating Interfacial Dynamics of Ti-Al Systems Using Molecular Dynamics Simulation and Markov State Modeling

Due to their remarkable mechanical and chemical properties, Ti-Al-based materials are attracting considerable interest in numerous fields of engineering, such as automotive, aerospace, and defense. With their low density, high strength, and resistance to corrosion and oxidation, these intermetallic alloys and metal-compound composites have found diverse applications. However, additive manufacturing and heat treatment of Ti-Al alloys frequently lead to brittleness and severe formation of defects. The present study delves into the interfacial dynamics of these Ti-Al systems, particularly focusing on the behavior of Ti and Al atoms in the presence of TiAl3 grain boundaries under experimental heat treatment conditions. Using a combination of molecular dynamics and Markov state modeling, we scrutinize the kinetic processes involved in the formation of TiAl3. The molecular dynamics simulation indicates that at the early stage of heat treatment, the predominating process is the diffusion of Al atoms toward the Ti surface through the TiAl3 grain boundaries. Markov state modeling identifies three distinct dynamic states of Al atoms within the Ti/Al mixture that forms during the process, each exhibiting a unique spatial distribution. Using transition time scales as a qualitative measure of the rapidness of the dynamics, it is observed that the Al dynamics is significantly less rapid near the Ti surface compared to the Al surface. Put together, the results offer a comprehensive understanding of the interfacial dynamics and reveal a three-stage diffusion mechanism. The process initiates with the premelting of Al, proceeds with the prevalent diffusion of Al atoms toward the Ti surface, and eventually ceases as the Ti concentration within the mixture progressively increases. The insights gained from this study could contribute significantly to the control and optimization of manufacturing processes for these high-performing Ti-Al-based materials.

Fundamental mechanistic insights into the catalytic reactions of Li─S redox by Co single-atom electrocatalysts via operando methods

Lithium-sulfur batteries represent an attractive option for energy storage applications. A deeper understanding of the multistep lithium-sulfur reactions and the electrocatalytic mechanisms are required to develop advanced, high-performance batteries. We have systematically investigated the lithium-sulfur redox processes catalyzed by a cobalt single-atom electrocatalyst (Co-SAs/NC) via operando confocal Raman microscopy and x-ray absorption spectroscopy (XAS). The real-time observations, based on potentiostatic measurements, indicate that Co-SAs/NC efficiently accelerates the lithium-sulfur reduction/oxidation reactions, which display zero-order kinetics. Under galvanostatic discharge conditions, the typical stepwise mechanism of long-chain and intermediate-chain polysulfides is transformed to a concurrent pathway under electrocatalysis. In addition, operando cobalt K-edge XAS studies elucidate the potential-dependent evolution of cobalt's oxidation state and the formation of cobalt-sulfur bonds. Our work provides fundamental insights into the mechanisms of catalyzed lithium-sulfur reactions via operando methods, enabling a deeper understanding of electrocatalysis and interfacial dynamics in electrical energy storage systems.

Deformation Rate-Adaptive Conducting Polymers and Composites

Materials are more easily damaged during accidents that involve rapid deformation. Here, a design strategy is described for electronic materials comprised of conducting polymers that defies this orthodox property, making their extensibility and toughness dynamically adaptive to deformation rates. This counterintuitive property is achieved through a morphology of interconnected nanoscopic core-shell micelles, where the chemical interactions are stronger within the shells than the cores. As a result, the interlinked shells retain material integrity under strain, while the rate of dissociation of the cores controls the extent of micelle elongation, which is a process that adapts to deformation rates. A prototype based on polyaniline shows a 7.5-fold increase in ultimate elongation and a 163-fold increase in toughness when deformed at increasing rates from 2.5 to 10 000% min-1 . This concept can be generalized to other conducting polymers and highly conductive composites to create "self-protective" soft electronic materials with enhanced durability under dynamic movement or deformation.

Biomass carbon mining to develop nature-inspired materials for a circular economy

A transition from a linear to a circular economy is the only alternative to reduce current pressures in natural resources. Our society must redefine our material sources, rethink our supply chains, improve our waste management, and redesign materials and products. Valorizing extensively available biomass wastes, as new carbon mines, and developing biobased materials that mimic nature's efficiency and wasteless procedures are the most promising avenues to achieve technical solutions for the global challenges ahead. Advances in materials processing, and characterization, as well as the rise of artificial intelligence, and machine learning, are supporting this transition to a new materials' mining. Location, cultural, and social aspects are also factors to consider. This perspective discusses new alternatives for carbon mining in biomass wastes, the valorization of biomass using available processing techniques, and the implementation of computational modeling, artificial intelligence, and machine learning to accelerate material's development and process engineering.

Computational Design of Antimicrobial Active Surfaces via Automated Bayesian Optimization

Biofilms pose significant problems for engineers in diverse fields, such as marine science, bioenergy, and biomedicine, where effective biofilm control is a long-term goal. The adhesion and surface mechanics of biofilms play crucial roles in generating and removing biofilm. Designing customized nanosurfaces with different surface topologies can alter the adhesive properties to remove biofilms more easily and greatly improve long-term biofilm control. To rapidly design such topologies, we employ individual-based modeling and Bayesian optimization to automate the design process and generate different active surfaces for effective biofilm removal. Our framework successfully generated optimized functional nanosurfaces for improved biofilm removal through applied shear and vibration. Densely distributed short pillar topography is the optimal geometry to prevent biofilm formation. Under fluidic shearing, the optimal topography is to sparsely distribute tall, slim, pillar-like structures. When subjected to either vertical or lateral vibrations, thick trapezoidal cones are found to be optimal. Optimizing the vibrational loading indicates a small vibration magnitude with relatively low frequencies is more efficient in removing biofilm. Our results provide insights into various engineering fields that require surface-mediated biofilm control. Our framework can also be applied to more general materials design and optimization.

Molecular Design and Preparation of Protein-Based Soft Ionic Conductors with Tunable Properties

Protein-based soft ionic conductors have attracted considerable research interest in recent years with great potential in applications at the human-machine interfaces. However, a fundamental mechanistic understanding of the ionic conductivity of silk-based ionic conductors is still unclear. Here, we first developed an environmental-friendly and scalable method to fabricate silk-based soft ionic conductors using silk proteins and calcium chloride. The mechanistic understanding of the ion transport and molecular interactions between calcium ions and silk proteins at variable water contents was investigated in-depth by combining experimental and simulation approaches. The results show that calcium ions primarily interact with amide groups in proteins at a low water content. The ionic conductivity is low since the calcium ions are confined around silk proteins within 2.0-2.6 Å. As water content increases, the calcium ions are hydrated with the formation of water shells, leading to the increased distance between calcium ions and silk proteins (3.3-6.0 Å). As a result, the motion of the calcium ions increased to achieve a higher ionic conductivity. By optimizing the ratio of the silk proteins, calcium ions, and water, silk-based soft ionic conductors with good stretchability and self-healing properties can be obtained. Such protein-based soft ionic conductors can be further used to fabricate smart devices such as electrochromic devices.

Cardiovascular structure and function assessed by MRI in healthy South Asians compared to White Europeans: a UK Biobank study

Background

There is limited data on ethnic specific comparisons for measures of cardiovascular structure and function in healthy cohorts. Echocardiographic data indicate South Asian's (SAs) have smaller mass and evidence of more concentric remodelling compared to White Europeans (WEs). Furthermore, there is no data published for strain or strain rates.

Purpose

To compare Cardiac Magnetic Resonance (CMR) derived measures of structure and function between age and sex matched healthy SAs and WEs from the UK biobank cohort.

Methods

South Asian and WE participants from the UK Biobank who underwent CMR imaging were included. Individuals with a history of cardiovascular disease, hypertension, obesity (BMI ≥30 kg/m2 in WEs and ≥27 kg/m2 in SAs) and diabetes were excluded. Ethnic groups were matched according to age and sex at recruitment. Cine images (bSSFP) were analysed blinded to participant details using commercially available software. Left ventricular (LV) mass, LV volumes, global longitudinal and circumferential systolic strain (GLS and GCS), together with peak early diastolic strain rates (PEDSR), were obtained. Data distributions were assessed and T-Test or Man Whitney U conducted as appropriate.

Results

Datasets from the UK biobank were screened (n=45000). After applying exclusion criteria, 111 pairs of matched SAs and WEs were available for analysis (n=69 male and n=42 female matched pairs). Mean age of the entire cohort was 58±8 years. Data has been corrected according to body surface area (BSA),(males: WE 2.0±0.1 vs SA 1.8±0.1 m2, p≤0.001; females: WE 1.7±0.2 vs SA 1.6±0.1 m2, p≤0.001). There was no difference in heart rate (males: WE 64.5±9.3 vs SA 65.8±9.6 bpm, p=0.113; females: WE 66.2±7.8 vs SA 69.5±10.3 bpm, p=0.125). Results by sex and ethnicity are displayed in table 1. In males there was no difference in ejection fraction (EF) or indexed LV end diastolic volume (LVEDV). However indexed mass and mass/volume ratio were significantly lower in SAs, and GLS but not GCS was significantly higher than in SAs. Longitudinal PEDSR were significantly higher in SAs than in WE. By contrast, SA females had significantly lower EF with no difference in indexed LVEDV compared to WE females. However, as seen with the males SA females had significantly lower indexed LV mass and mass/volume ratio compared to WE females. Finally, both GLS and GCS were significantly higher in SAs compared to WE females, whereas there was no difference in longitudinal PEDSR.

Conclusion

Substantial differences in cardiovascular structure and function exist between SA and WE ethnic groups, in both men and women. Contrary to previous echocardiographic studies, LV volumes were similar between ethnicities and SA have less, not increased, concentric remodelling than WE. These findings highlight the need for ethnicity and sex-specific healthy reference ranges derived from CMR.

Funding Acknowledgement

Type of funding sources: None.

Probing the alignment-dependent mechanical behaviors and time-evolutional aligning process of collagen scaffolds

Efficiently manipulating and reproducing collagen (COL) alignment in vitro remains challenging because many of the fundamental mechanisms underlying and guiding the alignment process are not known. We reconcile experiments and coarse-grained molecular dynamics simulations to investigate the mechanical behaviors of a growing COL scaffold and assay how changes in fiber alignment and various cross-linking densities impact their alignment dynamics under shear flow. We find higher cross-link densities and alignment levels significantly enhance the apparent tensile/shear moduli and strength of a bulk COL system, suggesting potential measures to facilitate the design of stronger COL based materials. Since fibril alignment plays a key factor in scaffold mechanics, we next investigate the molecular mechanism behind fibril alignment with Couette flow by computationally investigating the effects of COL's structural properties such as chain lengths, number of chains, tethering conditions, and initial COL conformations on the COL's final alignment level. Our computations suggest that longer chain lengths, more chains, greater amounts of tethering, and initial anisotropic COL conformations benefit the final alignment, but the effect of chain lengths may be more dominant over other factors. These results provide important parameters for consideration in manufacturing COL-based scaffolds where alignment and cross-linking are necessary for regulating performance.

POS0942 DEVELOPMENT OF PREDICTION MODEL FOR FLARE AFTER TAPERING OF TNF INHIBITORS IN PATIENTS WITH AXIAL SPONDYLOARTHRITIS

Background

Tumor necrosis factor inhibitors (TNFi) have become a mainstay of management for axial spondyloarthritis (axSpA). However, it remains unclear whether patients with axSpA should continue the standard-dose TNFi after achieving stable disease activity. Although complete discontinuation of TNFi is followed by early relapse in most cases, several studies documented that reduced doses of TNFi in patients with prolonged low disease activity showed similar effects on disease control and drug survival compared to standard dose of TNFi. One of the main problem in the dose-tapering strategies for TNFi is a selection of the appropriate patient. However, there has been a lack of robust evidence regarding clinical factors predicting the flare after tapering of TNFi in patients with axSpA.

Objectives

This study aims to develop and validate the prediction model to select the patients in whom tapering of TNFi does not lead to flare.

Methods

We used the data from Korean College of Rheumatology Biologics registry, which included a total of 1,730 patients receiving biologic DMARD from 2017 to 2019 in South Korea. In this study, a total of 526 patients who were initially treated with the standard-dose TNFi and tapered the dose after at least 1 year of the treatment were analyzed. Dose quotient (DQ, 0-1) was applied to quantified TNFi used during interval. The main outcome was an occurrence of flare defined as ASDAS-CRP score of ≥2.1 after 1 year of tapering TNFi. To develop the prediction model, clinical factors having relevant association (p < 0.1) with the outcome were first selected as candidate predictors. Logistic regression using a stepwise approach through backward elimination was used for the final model.

Results

Patients’ mean (SD) age was 37.5 (11.9) years, 418 (79.5%) were men, and 474 (90.1%) were HLA-B27 positive. Mean disease duration was 5.0 (6.1) years and 433 (82.3%) were TNF naïve. The mean BASFI and ASDAS-CRP at baseline were 3.4 (2.6) and 3.7 (1.0), respectively. Approximately two-thirds of the patients (65.8%) were initiated TNFi tapering at the first 1 or 2 years from baseline. At the time of TNFi tapering, the mean DQ was 0.67 (0.15) and 381 (72.4%) were prescribed concurrently with NSAIDs, and the mean BASFI and ASDAS-CRP were 1.3 (1.8) and 1.6 (0.9), respectively. During 12 months of follow up starting from the TNFi tapering, 127 (24.1%) experienced the flare. The multivariable analysis revealed that HLA-B27 positivity (OR 0.337; 95% CI 0.161-0.705; p=0.004), inflammatory back pain (OR 2.920; 95% CI 1.283-6.648; p=0.011), ASDAS-CRP at tapering (OR 2.798; 95% CI 2.030-3.856; p<0.001), and BASFI at tapering (OR 1.214; 95% CI 1.051-1.402; p=0.008) were significantly associated with flare. Based on the results of the logistic regression analysis, the predicted probability was calculated by the following formula: P=1/[1+ exp{-(1.088 x HLA-B27 negativity + 1.072 x inflammatory back pain + 1.567 x psoriasis + 0.623 x family history of axSpA + 1.092 x diabetes mellitus + 0.435 x DQ at TNFi tapering + 1.029 x ASDAS-CRP at TNFi tapering + 0.194 x BASFI at TNFi tapering)}]. The best cut-off value of the model to define the flare was 0.2416 (95% CI 0.176, 0.301) with sensitivity 74.0% and with specificity 81.0%. AUC was 0.828 (95% CI 0.786-0.869) indicating a good predication (Figure 1). The internal validation with bootstrapping showed minimal overfitting (estimated AUC 0.794) and good calibration between observed and predicted values (calibration slope 1.110, 95% CI 0.903, 1.317; intercept 0.026, 95% CI -0.091, 0.039).

Figure 1.

Apparent performance of developed model for prediction of flare after 12 months of tumor necrosis factor inhibitors tapering.

Conclusion

We developed the prediction model for the flare after 12 months of TNFi tapering in patients with axSpA. It might be applicable in real world setting, although external validation will be required in the future investigation.

References

[1]Zavada J, et al. Ann Rheum Dis. 2016;75(1):96-102.

Acknowledgements

We greatly thank to the the Clinical Research Committee of the Korean College of Rheumatology and all participating hospitals.

Disclosure of Interests

None declared

POS0068 CHANGES IN QUANTITATIVE INTERSTITIAL LUNG DISEASE SCORES ON HIGH-RESOLUTION CT IN IDIOPATHIC INFLAMMATORY MYOSITIS

Background

The idiopathic inflammatory myopathies (IIM) are autoimmune connective tissue diseases affecting skeletal muscle, skin and other organ systems. IIM-related interstitial lung disease (IIM-ILD) is the most common extra-muscular manifestation, being the leading cause of morbidity and mortality. Several studies have suggested that ILD pattern based on chest high-resolution computed tomography (HRCT) can be related to disease course and treatment response, but the results vary considerably. Moreover, the clinical impact of the quantitative ILD (QILD) score, a validated computer-aided scoring system in assessing ILD severity from HRCT, and its longitudinal changes have not yet been evaluated in IIM-ILD.

Objectives

This study aims to investigate ILD patterns and QILD scores in patients with IIM-ILD, to identify their clinical impact, and to delineate longitudinal changes of QILD measurement.

Methods

A total of 80 patients with IIM (polymyositis 22, and dermatomyositis 58) who underwent at least 2 times of serial HRCT scans were included. Visual ILD patterns were assessed by multiple thoracic radiologists. Quantitative analysis of HRCT was presented as total extent of QILD scores (%) in whole lung and most severe zone. Individual time-estimated ΔQILD score between first 2 visits was derived using a linear approximation of yearly change, where the duration of median (IQR) was 1.0 (0.4-1.6) years in the first 2 HRCT scans.

Results

The median (IQR) age of the patients was 52.0 (43.5-58.5) years and 60 (75.0%) were women. Baseline median score of whole lung-QILD and most severe zone-QILD were 28.1% (19.1-43.8) and 68.0% (45.5-81.8), respectively, and QILD score showed significant correlations with pulmonary function tests (r=-0.349, p=0.002 for % predicted forced vital capacity; and r=-0.381, p=0.001 for % predicted diffusing capacity for carbon monoxide). The individual time-estimated yearly ΔQILD score between first 2 visits presented that approximately half of the patients showed improvement or stability in QILD scores; however, when patients were sorted by visual assessment in ILD subtype on HRCT, approximately two-thirds of the patients with usual interstitial pneumonia (UIP) pattern were aggravated in QILD scores and less than half of subjects with nonspecific interstitial pneumonia and organizing pneumonia were aggravated (Figure 1, 80% for UIP vs. 44.4% for non-UIP, p=0.013). There was no immunosuppressive drugs related to meaningful improvement in QILD scores during first 2 visits. Notably, we observed significant aggravation of QILD scores in tacrolimus users (n=7, median time-estimated whole lung-yarly ΔQILD 20.3 (2.7-38.4)) compared with tacrolimus non-users (n=73, median time estimated whole lung-yearly ΔQILD -1.2 (-8.3-6.5)). Among 80 patients, 6 (7.5%) were died due to various lung complications. Higher baseline QILD scores were noted in deaths (median whole lung-QILD 45.4 (32.9-56.5)) than in survivors (median whole lung-QILD 26.9 (19.0-42.4)), albeit not significant (p=0.084). Poor survival rate was observed in patients with high grade of ground glass opacity by visual assessment in right upper lobe (log-rank test, p=0.042). Among subgroup of patients with 3 serial HRCT scans (n=41), dynamic changes of four distinct patterns (improving, worsening, convex, and concave) were observed.

Figure 1.

Cleveland dot plot of individual time-estimated yearly ΔQILD during fist 2 visits.

Conclusion

The changes in QILD score in IIM-ILD are dynamic and present different by visual assessment. QILD score has the potential for evaluation of the severity changes, prognosis and medication response in patients with IIM-ILD.

References

[1]Tashkin DP, et al. Ann Rheum Dis 2016;75(2):374-81.

7 truncated values in the graph A. NSIP: nonspecific interstitial pneumonia; OP: organizing pneumonia; UIP: usual interstitial pneumonia.

Disclosure of Interests

None declared

Engineering Natural and Recombinant Silks for Sustainable Biodevices

Silk fibroin (SF) is a structural protein derived from natural silkworm silks. Materials fabricated based on SF usually inherit extraordinary physical and biological properties, including high mechanical strength, toughness, optical transparency, tailorable biodegradability, and biocompatibility. Therefore, SF has attracted interest in the development of sustainable biodevices, especially for emergent bio-electronic technologies. To expand the function of current silk devices, the SF characteristic sequence has been used to synthesize recombinant silk proteins that benefit from SF and other functional peptides, such as stimuli-responsive elastin peptides. In addition to genetic engineering methods, innovated chemistry modification approaches and improved material processing techniques have also been developed for fabricating advanced silk materials with tailored chemical features and nanostructures. Herein, this review summarizes various methods to synthesize functional silk-based materials from different perspectives. This review also highlights the recent advances in the applications of natural and recombinant silks in tissue regeneration, soft robotics, and biosensors, using B. mori SF and silk-elastin-like proteins (SELPs) as examples.

Hybridly double-crosslinked carbon nanotube networks with combined strength and toughness via cooperative energy dissipation

Although chemical crosslinking has been extensively explored to enhance the mechanical properties of network-type materials for structural and energy (electrochemical, thermal, etc.) applications, loading-induced energy dissipations usually occur through a single channel that either leads to network brittleness or low strength/stiffness. In this work, we apply coarse-grained molecular dynamics simulations to explore the potential of hybridly double-crosslinked carbon nanotube (CNT) networks as a light weight functional material with combined strength and toughness. While increasing the crosslinking density or strong crosslink composition may, in general, enhance the strength and toughness, further increasing the two parameters would surprisingly lead to deteriorated strength and toughness. We find that double-crosslinked networks can nicely achieve cooperative energy dissipation with minimal structural damage. In particular, the weak crosslinks serve as "sacrificial bonds" to dissipate elastic energies from external loading, while the strong crosslinks act as "structure holders" and break at a much later stage during the tensile test. Therefore, the combination of more than one type of crosslinking with hybrid potential energy landscapes and breaking time scales can prevent premature simultaneous breaking of multiple strong crosslinks. By deploying intermediate amounts of weak and strong crosslinks, we observe an outstanding density-normalized strength of 227-2130 kPa m³ kg^-1 as compared to many structural materials and advanced nanocomposites. The crosslinking strategies developed here would pave new avenues for the rational design of functional network materials beyond CNTs, such as hydrogels, nanofibers, and nanocomposites.

The Impact of Foaming Effect on the Physical and Mechanical Properties of Foam Glasses with Molecular-Level Insights

Foaming effect strongly impacts the physical and mechanical properties of foam glass materials, but an understanding of its mechanism especially at the molecular level is still limited. In this study, the foaming effects of dextrin, a mixture of dextrin and carbon, and different carbon allotropes are investigated with respect to surface morphology as well as physical and mechanical properties, in which 1 wt.% carbon black is identified as an optimal choice for a well-balanced material property. More importantly, the different foaming effects are elucidated by all-atomistic molecular dynamics simulations with molecular-level insights into the structure–property relationships. The results show that smaller pores and more uniform pore structure benefit the mechanical properties of the foam glass samples. The foam glass samples show excellent chemical and thermal stability with 1 wt.% carbon as the foaming agent. Furthermore, the foaming effects of CaSO₄ and Na₂HPO₄ are investigated, which both create more uniform pore structures. This work may inspire more systematic approaches to control foaming effect for customized engineering needs by establishing molecular-level structure–property–process relationships, thereby, leading to efficient production of foam glass materials with desired foaming effects.

Thermo- and Ion-responsive Silk-elastin-like Proteins and Their Multiscale Mechanisms

Silk-elastin-like protein (SELP) is an excellent biocompatible and biodegradable material for hydrogels with tunable properties that can respond to multiple external stimuli. By integrating fully atomistic, replica exchange molecular dynamics...

Fiber-Based Biopolymer Processing as a Route toward Sustainability

Some of the most abundant biomass on earth is sequestered in fibrous biopolymers like cellulose, chitin, and silk. These types of natural materials offer unique and striking mechanical and functional features that have driven strong interest in their utility for a range of applications, while also matching environmental sustainability needs. However, these material systems are challenging to process in cost-competitive ways to compete with synthetic plastics due to the limited options for thermal processing. This results in the dominance of solution-based processing for fibrous biopolymers, which presents challenges for scaling, cost, and consistency in outcomes. However, new opportunities to utilize thermal processing with these types of biopolymers, as well as fibrillation approaches, can drive renewed opportunities to bridge this gap between synthetic plastic processing and fibrous biopolymers, while also holding sustainability goals as critical to long-term successful outcomes.

Specific osteogenesis imperfecta-related Gly substitutions in type I collagen induce distinct structural, mechanical, and dynamic characteristics

The stiffnesses, β-structures, hydrogen bonds, and vibrational modes of wild-type collagen triple helices are compared with osteogenesis imperfecta-related mutants using integrative structural and dynamic analysis via molecular dynamics simulations and Markov state models. Differences in these characteristics are strongly related to the unwound structural states in the mutated regions that are specific to each mutation.

Design and Production of Customizable and Highly Aligned Fibrillar Collagen Scaffolds

The ability to fabricate anisotropic collagenous materials rapidly and reproducibly has remained elusive despite decades of research. Balancing the natural propensity of monomeric collagen (COL) to spontaneously polymerize in vitro with the mild processing conditions needed to maintain its native substructure upon polymerization introduces challenges that are not easily amenable with off-the-shelf instrumentation. To overcome these challenges, we have designed a platform that simultaneously aligns type I COL fibrils under mild shear flow and builds up the material through layer-by-layer assembly. We explored the mechanisms propagating fibril alignment, targeting experimental variables such as shear rate, viscosity, and time. Coarse-grained molecular dynamics simulations were also employed to help understand how initial reaction conditions including chain length, indicative of initial polymerization, and chain density, indicative of concentration, in the reaction environment impact fibril growth and alignment. When taken together, the mechanistic insights gleaned from these studies inspired the design, iteration, fabrication, and then customization of the fibrous collagenous materials, illustrating a platform material that can be readily adapted to future tissue engineering applications.

Adapting undergraduate paediatric medical education to the challenges of COVID-19 pandemic: perspective of NUS Medicine

COVID-19 significantly impacted the teaching-learning-assessment activities in many medical schools. In this article, we discuss the impact of COVID-19 on the Yong Loo Lin School of Medicine, National University of Singapore, focusing on paediatric training and the adaptations of the system and the people. The school developed strategies to promptly disseminate information and safety measures to protect all its staff and students. By leveraging on the school’s infrastructure for technology-enabled learning, good-quality medical training and reliable assessments were able to be carried out swiftly. The paediatric curriculum was crafted based on these principles, and it provided distance-based learning with live and interactive sessions to teach core clinical skills. The faculty also tapped on standardised patients to provide consistent and life-like scenarios. Measures were implemented to minimise challenges with technology-enabled learning. Collectively, efforts from the staff, support from the leadership and students’ adaptations tremendously helped to ease the transition.

POS1386 ANGIOGRAPHIC CHARACTERISTICS OF VASCULOPATHY IN PATIENTS WITH CONNECTIVE TISSUE DISEASES

Background:

Vasculopathies are a heterogeneous group of morphologically and pathogenetically distinct vascular diseases. They include both non-inflammatory and inflammatory vasculopathies. Patients with connective tissue disease (CTD), including systemic sclerosis (SSc), dermatomyositis (DM), and polymyositis (PM), can develop a non-thrombotic proliferative vasculopathy (NTPV), a distinctive disease entity characterized by vascular wall proliferation without overt evidence of vascular inflammation and intraluminal thrombosis.

Objectives:

This study aimed to analyze the angiographic features of NTPV in patients with CTD, including SSc, DM, and PM in comparison to polyarteritis nodosa (PAN).

Methods:

Angiograms of 47 extremities (24 upper and 23 lower extremities) of 11 patients with CTD (6 SSc, 4 DM, and 1 PM), and 12 patients with PAN who presented with critical digital ischemia between January 2001 and May 2020 were analyzed. The degree and pattern of stenosis, occlusion, aneurysms, and neovascularization in proximal arteries (defined as arteries above the wrist and ankle) and distal arteries (defined as those at or below the wrist and ankle) were compared between CTD-vasculopathy and PAN.

Results:

Diffuse narrowing was significantly more frequent (66.1% vs. 38.0%; p=0.001), whereas multifocal stenosis was significantly less frequent (6.5% vs. 26.8%, p=0.002) in the CTD group than in the PAN group. All patients with CTD and 72.0% with PAN had diffuse narrowing in the distal arteries (p =0.010). Tapered occlusion was more frequent than abrupt occlusion in patients with CTD (43.5% vs. 11.3%). Abrupt occlusion (11.3% vs. 29.6%, p=0.010) and aneurysm formation (1.6% vs. 11.3%; p=0.037) were significantly less frequent in the CTD than in the PAN group. After 1 year, three patients (27.3%) in the CTD group and seven (58.3%) in the PAN group showed improvements in digital ischemia. Moreover, four patients (36.4%) in the CTD group and two (16.7%) in the PAN group underwent auto- or surgical amputation.

Conclusion:

Patients with CTD-vasculopathy exhibit more frequently diffuse smooth narrowing, tapered occlusion and delayed distal blood flow on conventional angiograms and worse outcomes than with PAN patients. Larger studies are needed to confirm the current findings.

References:

[1]Kahaleh MB. Vascular involvement in systemic sclerosis (SSc). Clin Exp Rheumatol. 2004;22(3 Suppl 33):S19-23.

[2]Lee JS, Kim H, Lee EB, Song YW, Park JK. Nonthrombotic proliferative vasculopathy associated with antiphospholipid antibodies: A case report and literature review. Mod Rheumatol. 2019;29(2):388-92.

Figure 1.

Angiographic features of CTD-vasculopathy and PAN.

Arteries in the (A) upper extremities and (B) lower extremities of patients with CTD-vasculopathy and PAN. Diffuse narrowing is indicated by white arrowheads; tapered occlusion by white arrows; multifocal stenosis by black arrowheads; abrupt occlusion by black arrows; aneurysmal changes by empty arrows; grade 2 tortuosity by white stars; and grade 3 tortuosity by black stars. CTD, connective tissue disease; PAN, polyarteritis nodosa.

Table 1.

Comparison of angiographic parameters between CTD-vasculopathy and PAN.

CTD (upper 14, lower 8)PAN (upper 10, lower 15)p-valueTotal number of images6271Shoulder/elbow/wrist and hand11/14/148/10/10Femoral/knee/ankle and foot7/8/813/15/15Stenosis Diffuse narrowing41/62 (66.1%)27/71 (38.0%)0.001  Focal stenosis13/62 (21.0%)10/71 (14.1%)0.295  Multifocal stenosis4/62 (6.5%)19/71 (26.8%)0.002Occlusion Tapered occlusion27/62 (43.5%)23/71 (32.4%)0.185  Abrupt occlusion7/62 (11.3%)21/71 (29.6%)0.010Aneurysm1/62 (1.6%)8/71 (11.3%)0.037Neovascularization in muscular branchTortuosity  Grade 145/62 (72.6%)30/68 (39.1%)0.002  Grade 211/62 (17.7%)14/68 (23.9%)  Grade 36/62 (9.7%)24/68 (37.0%)

Tortuosity grade 1, normal; grade 2, mild to moderate; grade 3, severe (hypertortuosity). CTD, connective tissue disease; PAN, polyarteritis nodosa.

Disclosure of Interests:

Jina Yeo: None declared, Eun-Ah Park: None declared, Eun Bong Lee Consultant of: Pfizer, Grant/research support from: GC Pharma and Handok Inc., Yeong Wook Song: None declared, Jin Kyun Park: None declared

POS0856 CLINICAL UTILITY OF BREATH-HOLDING TEST FOR MEASURING CARDIOPULMONARY FUNCTION IN PATIENTS WITH SYSTEMIC SCLEROSIS

Background:

Interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH) are major causes of death in systemic sclerosis (SSc). Six-minute-walk test (6MWT) is a standard outcome measure for exercise capacity in cardiopulmonary diseases. However, the results of 6MWT may not reflect real cardiopulmonary function of SSc patients in whom musculoskeletal system is frequently inflicted.

Objectives:

This study aimed to evaluate the clinical utility of breath-holding test (BHT) in evaluating cardiopulmonary function in SSc patients, as compared with 6MWT.

Methods:

Seventy-two patients with SSc were prospectively enrolled and underwent BHT and 6MWT with measurement of Borg score and Scleroderma Health Assessment Questionnaire (SHAQ). Data on diffusing capacity for carbon monoxide (DLCO, %), forced vital capacity (FVC, % and liters), and ejection fraction and pulmonary arterial systolic pressure (PASP) measured by transthoracic echocardiography (TTE), were also collected. For BHT, participants were required to make a maximum expiration followed by a maximum inspiration and to hold the breath as long as possible at maximum inspiratory level. This procedure was repeated three times, with 5-minute intervals. 6MWT was performed according to the American Thoracic Society guidelines. Pearson’s correlation test was applied to demonstrate the relationship between BHT results and each clinical parameter.

Results:

Among 72 (66 female) patients, mean (SD) age was 57.1 (11.1) years, modified Rodnan skin score 10.6 (10.5), SHAQ 0.64 (0.61) and 6MWT distance 473.5 (95.5) m. Mean BHT time was 35.05 (14.90) sec at the first time, 38.92 (16.14) sec at the second time, and 41.11 (17.71) sec at the third time. The BHT time showed a statistically significant negative correlation with Borg scale (pre-test, r = -0.336, p = 0.002; post-test, r = -0.252, p = 0.034; Figure 1 and Table 1), while 6MWT showed a negative correlation with only post-test Borg scale (pre-test, r = -0.113 p = 0.343; post-test, r = -0.351 p = 0.002; Table 1). The BHT time was positively correlated with DLCO (%, r = 0.409, p < 0.001) and FVC (liters, r = 0.402, p < 0.001) (Table 1). We also found a statistically significant correlation between BHT time and SHAQ score (r = -0.451, p < 0.001; Table 1). However, EF and PASP by TTE showed no significant relationship with BHT time (EF, r = -0.108, p = 0.374; PASP, r = -0.246, p = 0.054; Table 1).

Table 1.

Pearson’s correlation coefficients (r) for the relation between BHT and clinical parameters in comparison to 6MWT.

Pre-test Borg scalePost-test Borg scaleDLCO(%)FVC(L)FVC(%)FVC/DLCOEF(%)PSAP(mm Hg)SHAQ (score)BHT (sec)-0.366**-0.252*0.409***0.402**0.191-0.244***-0.108-0.246-0.451***6MWT (m)-0.113-0.351**0.297*0.321**0.063-0.250*0.137-0.354**-0.531***

BHT, breath-holding test; 6MWT, 6-minute-walk test; DLCO, diffusing capacity for carbon monoxide; FVC, forced vital capacity; EF, ejection fraction estimated by transthoracic echocardiography; SHAQ, Scleroderma Health Assessment Questionnaire

.* p < 0.05, ** p < 0.01, *** p < 0.001

Figure 1.

Association of Borg dyspnea scale with breath-holding time.

Conclusion:

The BHT is a simple, safe, and less time-consuming test, reflective of pulmonary parameters and SHAQ, as compared with 6MWT. Our results suggest that the BHT might be a useful surrogate marker of cardiopulmonary capacity in SSc patients.

References:

[1]Villalba WO, Sampaio-Barros PD, Pereira MC, Cerqueira EM, Leme CA, Jr., Marques-Neto JF, et al. Six-minute walk test for the evaluation of pulmonary disease severity in scleroderma patients. Chest. 2007;131(1):217-22.

[2]Garin MC, Highland KB, Silver RM, Strange C. Limitations to the 6-minute walk test in interstitial lung disease and pulmonary hypertension in scleroderma. J Rheumatol. 2009;36(2):330-6.

[3]Barnai M, Laki I, Gyurkovits K, Angyan L, Horvath G. Relationship between breath-hold time and physical performance in patients with cystic fibrosis. Eur J Appl Physiol. 2005;95(2-3):172-8.

Acknowledgements:

This study would not have been possible without help from research assistant, Sung-Soon Cho.

Disclosure of Interests:

Jina Yeo: None declared, Mi Hyeon Kim: None declared, Jun Won Park: None declared, Jin Kyun Park: None declared, Eun Bong Lee Consultant of: Pfizer, Grant/research support from: GC Pharma and Handok Inc.

Current Insights on the Diverse Structures and Functions in Bacterial Collagen-like Proteins

The dearth of knowledge on the diverse structures and functions in bacterial collagen-like proteins is in stark contrast to the deep grasp of structures and functions in mammalian collagen, the ubiquitous triple-helical scleroprotein that plays a central role in tissue architecture, extracellular matrix organization, and signal transduction. To fill and highlight existing gaps due to the general paucity of data on bacterial CLPs, we comprehensively reviewed the latest insight into their functional and structural diversity from multiple perspectives of biology, computational simulations, and materials engineering. The origins and discovery of bacterial CLPs were explored. Their genetic distribution and molecular architecture were analyzed, and their structural and functional diversity in various bacterial genera was examined. The principal roles of computational techniques in understanding bacterial CLPs' structural stability, mechanical properties, and biological functions were also considered. This review serves to drive further interest and development of bacterial CLPs, not only for addressing fundamental biological problems in collagen but also for engineering novel biomaterials. Hence, both biology and materials communities will greatly benefit from intensified research into the diverse structures and functions in bacterial collagen-like proteins.

Birefringent Silk Fibroin Hydrogel Constructed via Binary Solvent-Exchange-Induced Self-Assembly

Birefringent hydrogels have a strong potential for applications in biomedicine and optics as they can modulate the optical and mechanical anisotropy in confined two-dimensional geometries. However, production of birefringent hydrogels with hierarchical structures, mechanical properties, and biorelated behavior that are analogous to biological tissues is still challenging. Starting from the silk fibroin (SF)-ionic liquid solution system, this study aimed to rationally design a "binary solvent-exchange-induced self-assembly (BSEISA)" strategy to produce birefringent SF hydrogels (SFHs). In this method, the conformational transition rate of SF can be effectively controlled by the exchange rate of the binary solvents. Therefore, this method provides the possibility of controlling the conformation and orientation of SF. Molecular simulations confirmed that methanol is more effective in driving β-sheet formation than other often used solvents, such as formic acid and water. The formed β-sheets act as the physical cross-links that connect disparate protein chains, thereby forming continuous and stable three-dimensional (3D) hydrogel networks. The resultant BSEISA-SFHs are transparent and birefringent with mechanical characteristics similar to those of soft biological tissues, such as lens and cartilage. Interestingly, our results revealed that the evolution of experimental birefringent fringes perfectly matched the changes in stress distribution predicted using finite element analysis. Owing to the unique birefringence of BSEISA-SFHs, together with the advantages in mechanical performance, these hydrogels are anticipated to act as good tissue surrogates for understanding the mechanical response of biological tissues.

Wood-Derived Carbon with Selectively Introduced C═O Groups toward Stable and High Capacity Anodes for Sodium Storage

Biomass-derived carbon is a promising sustainable anode material for sodium-ion batteries (SIBs). Although the electrochemical performance can be improved by introducing functional groups, the selective introduction of single functional groups into biomass carbon remains difficult. Here, we overcome this challenge by developing a wood-derived carbon with selectively introduced C═O groups by combining tetramethoxysilane (TMOS) with wood cellulose pulps. The integration of TMOS introduces abundant C═O groups into the carbon during the polycondensation and pyrolysis process. The C═O groups play a dominant role in anode surface-controlled processes, and this leads to improvements in pseudo-capacity and fast electrode process kinetics. Besides, the introduction of C═O groups generates oxygen functional active sites that promote Na⁺ adsorption and creates a sufficiently large graphene interlayer distance. The as-obtained carbon shows a high capacity of 330 mAh g^-1 at 40 mA g^-1 and excellent cycling stability. Moreover, our strategy is simple and uses wood cellulose pulps as precursors. It therefore enables low-cost and large-scale synthesis of carbon anode materials for SIBs.

Possible instability of one-step replica symmetry breaking in p-spin Ising models outside mean-field theory

The fully connected Ising p-spin model has for p>2 a discontinuous phase transition from the paramagnetic phase to a stable state with one-step replica symmetry breaking (1RSB). However, simulations in three dimension do not look like these mean-field results and have features more like those which would arise with full replica symmetry breaking (FRSB). To help understand how this might come about we have studied in the fully connected p-spin model the state of two-step replica symmetry breaking (2RSB). It has a free energy degenerate with that of 1RSB, but the weight of the additional peak in P(q) vanishes. We expect that the state with full replica symmetry breaking (FRSB) is also degenerate with that of 1RSB. We suggest that finite-size effects will give a nonvanishing weight to the FRSB features, as also will fluctuations about the mean-field solution. Our conclusion is that outside the fully connected model in the thermodynamic limit, FRSB is to be expected rather than 1RSB.

Adverse effects of Alport syndrome-related Gly missense mutations on collagen type IV: Insights from molecular simulations and experiments

Patients with Alport syndrome (AS) exhibit blood and elevated protein levels in their urine, inflamed kidneys, and many other abnormalities. AS is attributed to mutations in type IV collagen genes, particularly glycine missense mutations in the collagenous domain of COL4A5 that disrupt common structural motifs in collagen from the repeat (Gly-Xaa-Yaa)_n amino acid sequence. To characterize and elucidate the molecular mechanisms underlying how AS-related mutations perturb the structure and function of type IV collagen, experimental studies and molecular simulations were integrated to investigate the structure, stability, protease sensitivity, and integrin binding affinity of collagen-like proteins containing amino acid sequences from the α5(IV) chain and AS-related Gly missense mutations. We show adverse effects where (i) three AS-related Gly missense mutations significantly reduced the structural stability of the collagen in terms of decreased melting temperatures and calorimetric enthalpies, in conjunction with a collective drop in the external work needed to unfold the peptides containing mutation sequences; (ii) due to local unwinding around the sites of mutations, these triple helical peptides were also degraded more rapidly by trypsin and chymotrypsin, as these enzymes could access the collagenous triple helix more easily and increase the number of contacts; (iii) the mutations further abolished the ability of the recombinant collagens to bind to integrins and greatly reduced the binding affinities between collagen and integrins, thus preventing cells from adhering to these mutants. Our unified experimental and computational approach provided underlying insights needed to guide potential therapies for AS that ameliorate the adverse effects from AS disease onset and progression.

Discovery and design of soft polymeric bio-inspired materials with multiscale simulations and artificial intelligence

Establishing the “Materials 4.0” paradigm requires intimate knowledge of the virtual space in materials design.

Conductive Silk-Based Composites Using Biobased Carbon Materials

There is great interest in developing conductive biomaterials for the manufacturing of sensors or flexible electronics with applications in healthcare, tracking human motion, or in situ strain measurements. These biomaterials aim to overcome the mismatch in mechanical properties at the interface between typical rigid semiconductor sensors and soft, often uneven biological surfaces or tissues for in vivo and ex vivo applications. Here, the use of biobased carbons to fabricate conductive, highly stretchable, flexible, and biocompatible silk-based composite biomaterials is demonstrated. Biobased carbons are synthesized via hydrothermal processing, an aqueous thermochemical method that converts biomass into a carbonaceous material that can be applied upon activation as conductive filler in composite biomaterials. Experimental synthesis and full-atomistic molecular dynamics modeling are combined to synthesize and characterize these conductive composite biomaterials, made entirely from renewable sources and with promising applications in fields like biomedicine, energy, and electronics.

Multiscale Design of Graphyne-Based Materials for High-Performance Separation Membranes

By varying the number of acetylenic linkages connecting aromatic rings, a new family of atomically thin graph-n-yne materials can be designed and synthesized. Generating immense scientific interest due to its structural diversity and excellent physical properties, graph-n-yne has opened new avenues toward numerous promising engineering applications, especially for separation membranes with precise pore sizes. Having these tunable pore sizes in combination with their excellent mechanical strength to withstand high pressures, free-standing graph-n-yne is theoretically posited to be an outstanding membrane material for separating or purifying mixtures of either gases or liquids, rivaling or even dramatically exceeding the capabilities of current, state-of-art separation membranes. Computational modeling and simulations play an integral role in the bottom-up design and characterization of these graph-n-yne materials. Thus, here, the state of the art in modeling α-, β-, γ-, δ-, and 6,6,12-graphyne nanosheets for synthesizing graph-2-yne materials and 3D architectures thereof is discussed. Different synthesis methods are described and a broad overview of computational characterizations of graph-n-yne's electrical, chemical, and thermal properties is provided. Furthermore, a series of in-depth computational studies that delve into the specifics of graph-n-yne's mechanical strength and porosity, which confer superior performance for separation and desalination membranes, are reviewed.

Dynamic pigmentary and structural coloration within cephalopod chromatophore organs

Chromatophore organs in cephalopod skin are known to produce ultra-fast changes in appearance for camouflage and communication. Light-scattering pigment granules within chromatocytes have been presumed to be the sole source of coloration in these complex organs. We report the discovery of structural coloration emanating in precise register with expanded pigmented chromatocytes. Concurrently, using an annotated squid chromatophore proteome together with microscopy, we identify a likely biochemical component of this reflective coloration as reflectin proteins distributed in sheath cells that envelop each chromatocyte. Additionally, within the chromatocytes, where the pigment resides in nanostructured granules, we find the lens protein Ω- crystallin interfacing tightly with pigment molecules. These findings offer fresh perspectives on the intricate biophotonic interplay between pigmentary and structural coloration elements tightly co-located within the same dynamic flexible organ - a feature that may help inspire the development of new classes of engineered materials that change color and pattern.

Paraffin-enabled graphene transfer

The performance and reliability of large-area graphene grown by chemical vapor deposition are often limited by the presence of wrinkles and the transfer-process-induced polymer residue. Here, we report a transfer approach using paraffin as a support layer, whose thermal properties, low chemical reactivity and non-covalent affinity to graphene enable transfer of wrinkle-reduced and clean large-area graphene. The paraffin-transferred graphene has smooth morphology and high electrical reliability with uniform sheet resistance with ~1% deviation over a centimeter-scale area. Electronic devices fabricated on such smooth graphene exhibit electrical performance approaching that of intrinsic graphene with small Dirac points and high carrier mobility (hole mobility = 14,215 cm² V⁻¹ s⁻¹; electron mobility = 7438 cm² V⁻¹ s⁻¹), without the need of further annealing treatment. The paraffin-enabled transfer process could open realms for the development of high-performance ubiquitous electronics based on large-area two-dimensional materials.

The transfer process of as-grown graphene limits its electrical performance and reliability. Here, the authors develop a transfer approach using paraffin as a support layer and obtain wrinkle-reduced and clean large-area graphene retaining high mobility.

Fabrication and Characterization of Recombinant Silk-Elastin-Like-Protein (SELP) Fiber

Silk-elastin-like-protein polymers (SELPs) are genetically engineered recombinant protein sequences consisting of repeating units of silk-like and elastin-like blocks. By combining these entities, it is shown that both the characteristic strength of silk and the temperature-dependent responsiveness of elastin can be leveraged to create an enhanced stimuli-responsive material. It is hypothesized that SELP behavior can be influenced by varying the silk-to-elastin ratio. If the responsiveness of the material at different ratios is significantly different, this would allow for the design of materials with specific temperature-based swelling and mechanical properties. This study demonstrates that SELP fiber properties can be controlled via a temperature transition dependent on the ratio of silk-to-elastin in the material. SELP fibers are experimentally wet spun from polymers with different ratios of silk-to-elastin and conditioned in either a below or above transition temperature (T t ) water bath prior to characterization. The fibers with higher elastin content showed more stimuli-responsive behavior compared to the fibers with lower elastin content in the hot (57-60 °C) versus cold (4-7 °C) environment, both computationally and experimentally. This work builds a foundation for developing SELP materials with well-characterized mechanical properties and responsive features.

Multiscale Modeling of Silk and Silk-Based Biomaterials-A Review

Silk embodies outstanding material properties and biologically relevant functions achieved through a delicate hierarchical structure. It can be used to create high-performance, multifunctional, and biocompatible materials through mild processes and careful rational material designs. To achieve this goal, computational modeling has proven to be a powerful platform to unravel the causes of the excellent mechanical properties of silk, to predict the properties of the biomaterials derived thereof, and to assist in devising new manufacturing strategies. Fine-scale modeling has been done mainly through all-atom and coarse-grained molecular dynamics simulations, which offer a bottom-up description of silk. In this work, a selection of relevant contributions of computational modeling is reviewed to understand the properties of natural silk, and to the design of silk-based materials, especially combined with experimental methods. Future research directions are also pointed out, including approaches such as 3D printing and machine learning, that may enable a high throughput design and manufacturing of silk-based biomaterials.

Disparate effects of antibiotics on hypertension

Gut microbiota are associated with a variety of complex polygenic diseases. The usage of broad-spectrum antibiotics by patients affected by such diseases is an important environmental factor to consider, because antibiotics, which are widely prescribed to curb pathological bacterial infections, also indiscriminately eliminate gut commensal microbiota. However, the extent to which antibiotics reshape gut microbiota and per se contribute to these complex diseases is understudied. Because genetics play an important role in predisposing individuals to these modern diseases, we hypothesize that the extent to which antibiotics influence complex diseases depends on the host genome and metagenome. The current study tests this hypothesis in the context of hypertension, which is a serious risk factor for cardiovascular diseases. A 3 × 2 factorial design was used to test the blood pressure (BP) and microbiotal effects of three different antibiotics, neomycin, minocycline, and vancomycin, on two well-known, preclinical, genetic models of hypertension, the Dahl salt-sensitive (S) rat and the spontaneously hypertensive rat (SHR), both of which develop hypertension, but for different genetic reasons. Regardless of the class, oral administration of antibiotics increased systolic blood pressure of the S rat, while minocycline and vancomycin, but not neomycin, lowered systolic blood pressure in the SHR. These disparate BP effects were accompanied by significant alterations in gut microbiota. Our study highlights the need to consider an individualized approach for the usage of antibiotics among hypertensives, as their BP could be affected differentially based on their individual genetic and microbiotal communities.

Unraveling the Molecular Mechanisms of Thermo-responsive Properties of Silk-Elastin-Like Proteins by Integrating Multiscale Modeling and Experiment

Adaptive hydrogels tailor-made from silk-elastin-like proteins (SELPs) possess excellent biocompatibility and biodegradability with properties that are tunable and responsive to multiple simultaneous external stimuli. To unravel the molecular mechanisms of their physical response to external stimuli in tandem with experiments, here we predict and measure the variation in structural properties as a function of temperature through coarse-grained (CG) modeling of individual and crosslinked SE8Y and S4E8Y molecules, which have ratios of 1:8 and 4:8 of silk to elastin blocks respectively. Extensive structural reshuffling in single SE8Y molecules led to the increased compactness of the structure, whereas S4E8Y molecules did not experience any significant changes as they already adopted very compact structures at low temperatures. Crosslinking of SE8Y molecules at high concentrations impeded their structural transition at high temperatures that drastically reduced the degree of deswelling through extensive suppression of the structural shuffling and the trapping of the molecules in high potential energy states due to inter-molecular constraints. This integrative experimental and computational understanding of the thermal response in single molecules of SELPs and their crosslinked networks should lead to further improvements in the properties of SELP hydrogels through predictive designs and their wider applications in biomaterials and tissue engineering.

Materials-by-Design: Computation, Synthesis, and Characterization from Atoms to Structures

In the 50 years that succeeded Richard Feynman's exposition of the idea that there is "plenty of room at the bottom" for manipulating individual atoms for the synthesis and manufacturing processing of materials, the materials-by-design paradigm is being developed gradually through synergistic integration of experimental material synthesis and characterization with predictive computational modeling and optimization. This paper reviews how this paradigm creates the possibility to develop materials according to specific, rational designs from the molecular to the macroscopic scale. We discuss promising techniques in experimental small-scale material synthesis and large-scale fabrication methods to manipulate atomistic or macroscale structures, which can be designed by computational modeling. These include recombinant protein technology to produce peptides and proteins with tailored sequences encoded by recombinant DNA, self-assembly processes induced by conformational transition of proteins, additive manufacturing for designing complex structures, and qualitative and quantitative characterization of materials at different length scales. We describe important material characterization techniques using numerous methods of spectroscopy and microscopy. We detail numerous multi-scale computational modeling techniques that complements these experimental techniques: DFT at the atomistic scale; fully atomistic and coarse-grain molecular dynamics at the molecular to mesoscale; continuum modeling at the macroscale. Additionally, we present case studies that utilize experimental and computational approaches in an integrated manner to broaden our understanding of the properties of two-dimensional materials and materials based on silk and silk-elastin-like proteins.