Rheological Characterization and 3D Fabrication of Artificial Bacterial Biofilms.

Biofilms are significantly involved in the progression of many diseases, such as cancer and upper respiratory infections, due to their ability to adhere to soft tissues. Factors influencing biofilm development have been extensively studied on planar substrates; however, there is limited understanding regarding biofilm growth and interactions within 3D matrices. Developing biofilm models that closely mimic natural bacterial communities' chemical and mechanical properties in soft tissues is essential for developing next-generation antibacterial compounds and therapeutics, as 3D biofilms are more complex and less susceptible to treatment than their 2D counterparts.

A novel approach to forecasting reproduction numbers of spatiotemporal stochastic epidemic spread using a PDE-based model and real-time infection data.

The COVID-19 pandemic highlighted the need for improved epidemic spread forecasting, a critical precursor for developing optimal control measures for spread mitigation. Well-recognized shortcomings in computing basic and effective reproduction numbers ( , )-fundamental metrics for forecasting-underscore the need for new methods for estimating them from available data. We present a novel computational framework for estimating reproduction numbers from empirical spread data.

Tuning Printability and Adhesion of a Silver-Based Ink for High-Performance Strain Gauges Manufactured via Direct Ink Writing.

Structural health monitoring (SHM) systems are critical in ensuring the safety of space exploration, as spacecraft and structures can experience detrimental stresses and strains. By deploying conventional strain gauges, SHM systems can promptly detect and assess localized strain behaviors in structures; however, these strain gauges are limited by low sensitivity (gauge factor, GF ∼ 2). This study introduces an approach to printing strain gauges with high sensitivity, while also considering stretchability and long-term durability.

Instabilities and self-organization in spatiotemporal epidemic dynamics driven by nonlinearity and noise.

Theoretical analysis of epidemic dynamics has attracted significant attention in the aftermath of the COVID-19 pandemic. In this article, we study dynamic instabilities in a spatiotemporal compartmental epidemic model represented by a stochastic system of coupled partial differential equations (SPDE). Saturation effects in infection spread-anchored in physical considerations-lead to strong nonlinearities in the SPDE.

Differential modulation of cellular phenotype and drug sensitivity by extracellular matrix proteins in primary and metastatic pancreatic cancer cells.

Pancreatic ductal adenocarcinoma (PDAC) is reported to be the third highest cause of cancer-related deaths in the United States. PDAC is known for its high proportion of stroma, which accounts for 90% of the tumor mass. The stroma is made up of extracellular matrix (ECM) and nonmalignant cells such as inflammatory cells, cancer-associated fibroblasts, and lymphatic and blood vessels.

Polyaromatic hydrocarbons (PAHs) in the water environment: A review on toxicity, microbial biodegradation, systematic biological advancements, and environmental fate.

Polycyclic aromatic hydrocarbons (PAHs) are considered a major class of organic contaminants or pollutants, which are poisonous, mutagenic, genotoxic, and/or carcinogenic. Due to their ubiquitous occurrence and recalcitrance, PAHs-related pollution possesses significant public health and environmental concerns. Increasing the understanding of PAHs' negative impacts on ecosystems and human health has encouraged more researchers to focus on eliminating these pollutants from the environment.

Memory in aging colloidal gels with time-varying attraction.

We report a combined rheology, x-ray photon correlation spectroscopy, and modeling study of gel formation and aging in suspensions of nanocolloidal spheres with volume fractions of 0.20 and 0.43 and with a short-range attraction whose strength is tuned by changing temperature.

Rheological characterization of cell-laden alginate-gelatin hydrogels for 3D biofabrication.

Biofabrication of tissue models that closely mimic the tumor microenvironment is necessary for high-throughput anticancer therapeutics. Extrusion-based bioprinting of heterogeneous cell-laden hydrogels has shown promise in advancing rapid artificial tissue development. A major bottleneck limiting the rapid production of physiologically relevant tissue models is the current limitation in effectively printing large populations of cells.

Non-Pharmaceutical Interventions as Controls to mitigate the spread of epidemics: An analysis using a spatiotemporal PDE model and COVID-19 data.

We investigate the spatiotemporal dynamics and control of an epidemic using a partial differential equation (PDE) based Susceptible-Latent-Infected-Recovered (SLIR) model. We first validate the model using empirical COVID-19 data corresponding to a period of 45 days from the state of Ohio, United States. Upon optimizing the model parameters in the learning phase of the analysis using actual infection data from a period of the first 30 days, we then find that the model output closely tracks the actual data for the next 15 days.

Halogen Etch of TiAlC MAX Phase for MXene Fabrication.

The versatile property suite of two-dimensional MXenes is driving interest in various applications, including energy storage, electromagnetic shielding, and conductive coatings. Conventionally, MXenes are synthesized by a wet-chemical etching of the parent MAX-phase in HF-containing media. The acute toxicity of HF hinders scale-up, and competing surface hydrolysis challenges control of surface composition and grafting methods.

20 µs-resolved high-throughput X-ray photon correlation spectroscopy on a 500k pixel detector enabled by data-management workflow.

The performance of the new 52 kHz frame rate Rigaku XSPA-500k detector was characterized on beamline 8-ID-I at the Advanced Photon Source at Argonne for X-ray photon correlation spectroscopy (XPCS) applications. Due to the large data flow produced by this detector (0.2 PB of data per 24 h of continuous operation), a workflow system was deployed that uses the Advanced Photon Source data-management (DM) system and high-performance software to rapidly reduce area-detector data to multi-tau and two-time correlation functions in near real time, providing human-in-the-loop feedback to experimenters.

Analysis of epidemic spread dynamics using a PDE model and COVID-19 data from Hamilton County OH USA.

We study the spatiotemporal dynamics of an epidemic spread using a compartmentalized PDE model. The model is validated using COVID-19 data from Hamilton County, Ohio, USA. The model parameters are estimated using a month of recorded data and then used to forecast the infection spread over the next ten days.

Absorbent-Adsorbates: Large Amphiphilic Janus Microgels as Droplet Stabilizers.

Microgel particles are cross-linked polymer networks that absorb certain liquids causing network expansion. The type of swelling fluid and extent of volume change depends on the polymer-liquid interaction and the network's cross-link density. These colloidal gels can be used to stabilize emulsion drops by adsorbing to the interface of two immiscible fluids.

Reducing variation in hospital mortality for alcohol-related liver disease in North West England.

Background: Variations in emergency care quality for alcohol-related liver disease (ARLD) have been highlighted.

Aim: To determine whether introduction of a regional quality improvement (QI) programme was associated with a reduction in potentially avoidable inpatient mortality.

Method: Retrospective observational cohort study using hospital administrative data spanning a 1-year period before (2014/2015) and 3 years after a QI initiative at seven acute hospitals in North West England.

Stimuli responsive Janus microgels with convertible hydrophilicity for controlled emulsion destabilization.

Although the utilization of rigid particles can afford stable emulsions, some applications require eventual emulsion destabilization to release contents captured in the particle-covered droplet. This destabilizing effect is achieved when using stabilizers that respond to controlled changes in environment. Microgels can be synthesized as stimuli responsive polymeric gel networks that adsorb to oil/water interfaces and stabilize emulsions.

Evolution of structure and dynamics of thermo-reversible nanoparticle gels-A combined XPCS and rheology study.

A combined X-ray photon correlation spectroscopy and rheology study is carried out to capture the evolution of structure, fast particle-scale dynamics, and moduli (elastic and loss) at early times of gel formation near the fluid-gel boundary of a suspension of nanoparticles. The system is comprised of moderately concentrated suspensions of octadecyl silica in decalin (ϕ = 0.2) undergoing thermoreversible gelation.

Dielectric Properties for Nanocomposites Comparing Commercial and Synthetic Ni- and FeO-Loaded Polystyrene.

Nanomaterial-loaded thermoplastics are attractive for applications in adaptive printing methods, as the physical properties of the printed materials are dependent on the nanomaterial type and degree of dispersion. This study compares the dispersion and the impact on the dielectric properties of two common nanoparticles, nickel and iron oxide, loaded into polystyrene. Comparisons between commercial and synthetically prepared samples indicate that well-passivated synthetically prepared nanomaterials are dispersed and minimize the impact on the dielectric properties of the host polymer by limiting particle-particle contacts.

Millimeter-Size Pickering Emulsions Stabilized with Janus Microparticles.

The ability to make stable water-in-oil and oil-in-water millimeter-size Pickering emulsions is demonstrated using Janus particles-particles with distinct surface chemistries. The use of a highly cross-linked hydrophobic polymer network and the excellent water-wetting nature of a hydrogel as the hydrophobic and hydrophilic sides, respectively, permit distinct wettability on the Janus particle. Glass capillary microfluidics allows the synthesis of Janus particles with controlled sizes between 128 and 440 μm and control over the hydrophilic-to-hydrophobic domain volume ratio of the particle from 0.

Cationic carrier peptide enhances cerebrovascular targeting of nanoparticles in Alzheimer's disease brain.

Accumulation of amyloid beta (Aβ) peptides in the cerebral vasculature, referred to as cerebral amyloid angiopathy (CAA), is widely observed in Alzheimer's disease (AD) brain and was shown to accelerate cognitive decline. There is no effective method for detecting cerebrovascular amyloid (CVA) and treat CAA. The targeted nanoparticles developed in this study effectively migrated from the blood flow to the vascular endothelium as determined by using quartz crystal microbalance with dissipation monitoring (QCM-D) technology.

Enhanced gel formation in binary mixtures of nanocolloids with short-range attraction.

Colloidal suspensions transform between fluid and disordered solid states as parameters such as the colloid volume fraction and the strength and nature of the colloidal interactions are varied. Seemingly subtle changes in the characteristics of the colloids can markedly alter the mechanical rigidity and flow behavior of these soft composite materials. This sensitivity creates both a scientific challenge and an opportunity for designing suspensions for specific applications.

Dynamic Scaling of Colloidal Gel Formation at Intermediate Concentrations.

We have examined the formation and dissolution of gels composed of intermediate volume-fraction nanoparticles with temperature-dependent short-range attractions using small-angle x-ray scattering, x-ray photon correlation spectroscopy, and rheology to obtain nanoscale and macroscale sensitivity to structure and dynamics. Gel formation after temperature quenches to the vicinity of the rheologically determined gel temperature, T_{gel}, was characterized via the slowdown of dynamics and changes in microstructure observed in the intensity autocorrelation functions and structure factor, respectively, as a function of quench depth (ΔT=T_{quench}-T_{gel}), wave vector, and formation time t_{f}. We find the wave-vector-dependent dynamics, microstructure, and rheology at a particular ΔT and t_{f} map to those at other ΔTs and t_{f}s via an effective scaling temperature, T_{s}.

Stability of Polymer Grafted Nanoparticle Monolayers: Impact of Architecture and Polymer-Substrate Interactions on Dewetting.

The stability of polymer thin films is crucial to a broad range of technologies, including sensors, energy storage, filtration, and lithography. Recently, the demonstration of rapid deposition on solid substrates of ordered monolayers of polymer grafted nanoparticles (PGN) has increased potential for inks to additively manufacture such components. Herein, enhanced stability against dewetting of these self-assembled PGN films (gold nanoparticle functionalized with polystyrene (AuNP-PS)) is discussed in context to linear polystyrene (PS) analogues using high throughput surface gradients: surface energy (20-45 mN/m) and temperature (90-160 °C).

Phosphorescent Molecular Butterflies with Controlled Potential-Energy Surfaces and Their Application as Luminescent Viscosity Sensor.

We report precise manipulation of the potential-energy surfaces (PESs) of a series of butterfly-like pyrazolate-bridged platinum binuclear complexes, by synthetic control of the electronic structure of the cyclometallating ligand and the steric bulkiness of the pyrazolate bridging ligand. Color tuning of dual emission from blue/red, to green/red and red/deep red were achieved for these phosphorescent molecular butterflies, which have two well-controlled energy minima on the PESs. The environmentally dependent photoluminescence of these molecular butterflies enabled their application as self-referenced luminescent viscosity sensor.

Stochastic non-linear oscillator models of EEG: the Alzheimer's disease case.

In this article, the Electroencephalography (EEG) signal of the human brain is modeled as the output of stochastic non-linear coupled oscillator networks. It is shown that EEG signals recorded under different brain states in healthy as well as Alzheimer's disease (AD) patients may be understood as distinct, statistically significant realizations of the model. EEG signals recorded during resting eyes-open (EO) and eyes-closed (EC) resting conditions in a pilot study with AD patients and age-matched healthy control subjects (CTL) are employed.

Echoes in x-ray speckles track nanometer-scale plastic events in colloidal gels under shear.

We report x-ray photon correlation spectroscopy experiments on a concentrated nanocolloidal gel subject to in situ oscillatory shear strain. The strain causes periodic echoes in the speckle pattern that lead to peaks in the intensity autocorrelation function. Above a threshold strain that is near the first yield point of the gel, the peak amplitude decays exponentially with the number of shear cycles, signaling irreversible particle rearrangements.