The mountain communities of late-first millennium bc Italy have been regarded as non-urban societies that reverted to city life mainly owing to Roman intervention. A growing body of archaeological evidence is uncovering the diversity of settlement forms and dynamics in the region's pre-Roman past, which included sites encompassing a range of functions and social agents. This article presents an in-depth, microscale analysis of one such site, Monte Vairano in Samnium, drawing on perspectives from comparative urbanism. Monte Vairano developed urban characteristics such as a complex socioeconomic profile and political cohesion, as well as potentially more unique features such as an apparently balanced distribution of wealth. These results can shed further light on the diversity of ancient urbanization and its sociopolitical implications in late-first millennium bc Italy and the Mediterranean.

Tumors, trauma, and congenital defects require volume restoration of soft tissues. Tissue engineering provides an alternative source for substituting these defects. Cell encapsulation into hydrogels provides a three-dimensional microenvironment. Spheroids of cells provide close packing and increase cell-to-cell contacts resulting in differentiation. Gelatin is a natural polymer with low immunogenicity and preserved amino acid motifs for cell adhesion and proliferation. In the present study, a soft photo-crosslinked gelatin methacrylate (GelMA) hydrogel with long in vitro lifetime was synthesized. Stem cells (dental pulp derived, DPSC) and endothelial cells (umbilical cord derived, HUVEC) were formed into spheroids to induce prevascular network formation and encapsulated into GelMA (10% weight/volume). Results showed high cell viability, better gel mechanical properties, and longer HUVEC sprouting with spheroids compared to the same combination of cells. Altogether, the photo-crosslinked GelMA hydrogels with DPSC and HUVEC spheroids provided a promising tissue engineering and vascularization strategy in vitro.

Polymer nanocomposites possess unique sets of properties that make them suitable for different applications, including structural and flame-retardant material, electromagnetic wave reflector, sensors, thin film transistor, flexible display, and many more. The properties of these nanocomposite are dependent on nanofiller dispersion and bonding with polymer matrix (i.e. particle-matrix interaction). Thermography is a non-destructive method that may be used to gain insight into dispersion and particle-matrix interaction. Infrared (IR) radiation emitted from these nanomaterial polymer composite depends on the emissivity of the individual components. In addition, during flash heating and cooling, different thermal conductivity of components in the nanocomposite can influence pixel intensity differently in the IR image or video being captured. We have used an economical mid wavelength IR camera Fluke RSE600 equipped with a close-up macro lens and algorithm based on MATLAB image processing toolbox to analyse dispersion, voids and thermal diffusivity of patented graphene polymer nanocomposite materials (G-PMC) in micro-scale. These G-PMCs can act as a standard material to determine the potential of our IR thermography technique due to their homogeneity and lack of impurity due to unique fabrication process. Thermal diffusivity and dispersion of nanoparticles in our G-PMCs was estimated after irradiation with a xenon flash lamp by spatially mapping transient IR radiations from different G-PMCs using the Fluke RSE600 thermal imager. Results from thermography experiments were compared with scanning electron microscope (SEM) and Raman spectroscopy results. Micro-scale thermography was able to detect millimetre scale thermal diffusivity variation in the injection molded G-PMC samples and relate it to change in dispersion of nanofillers, unlike SEM and Raman, where micro-scale measurements could not determine the reason behind millimetre scale property variation. We believe this low cost, fast, micro-scale, non-destructive technique will provide valuable insight into functional polymer nanocomposite fabrication and corresponding electrical and thermal properties.

The effect of length scale on mechanical strength is a significant consideration for semiconductor materials. In III-V semiconductors, such as InSb, a transition from partial to perfect dislocations occurs at the brittle-to-ductile transition temperature (~150 °C for InSb). High temperature micro-compression reveals InSb to show a small size effect below the transition, similar to ceramics, while in the ductile regime it shows a size effect consistent with fcc metals. The source truncation model is found to agree with the observed trends in strength with size once the change in Burgers vector and bulk strength are taken into account.

Microsupercapacitors (MSCs) are miniaturized energy storage devices that can be integrated in an on-chip platform as a component of a power supply for Internet of things’ sensors. Integration of these on-chip MSCs require them to be fabricated through CMOS compatible fabrication techniques such as spin coating. One of the biggest challenges in spin coated MSCs is the poor surface adhesion. In this work, we present a CMOS compatible electrode deposition process with enhanced adhesion and retention for reduced graphene oxide (rGO) using spin coating. In order to improve the adhesion and surface uniformity of the deposited electrode material, the surface of Si/SiO2 wafers was subjected to roughening through Fe nanoparticle formation. A 4 nm thick Fe layer deposition substantially magnified the average mean surface roughness of the substrates. In comparison with substrates without the Fe deposition, the treated ones have more than 300% improvement in surface coverage and rGO mass retention after sonication testing. These results suggest that the surface roughening has a positive influence on electrode deposition via a spin-coating method.

Embolic beads for transarterial chemoembolization (TACE) should possess radiopacity and biodegradability at the same time, to be visualized in a body under fluoroscopy and CT scanning to avoid complicating disease. In this study, we fabricated radiopaque and biodegradable beads composed of Lipiodol (LPD) (ethiodized oil) and polycaprolactone (PCL), a biocompatible and biodegradable polymer. LPD/PCL beads were first fabricated with a home-made microfluidic device. By changing the flow-rate ratio in the microfluidic device, the mean diameter of LPD/PCL beads could be well controlled. The radiopacity was evaluated by the fluoroscopic imaging and the CT number measurements. Furthermore, the biodegradability was evaluated by collecting the weight loss data of LPD/PCL immersed in lipase/PBS solution and PBS. The results showed that LPD/PCL beads obtained in this study had sufficient radiopacity and biodegradability, which would be an alternative embolic agent for TACE.

There is growing evidence that minimizing the mechanical mismatch between neural implants and brain tissue mitigates inflammatory, biological responses at the interface under long-term implant conditions. The goal of this study is to develop a brain-like soft, conductive neural interface and use an improvised, penetrating microindentation technique reported by us earlier to quantitatively assess the (a) elastic modulus of the neural interface after implantation, (b) mechanical stresses during penetration of the probe, and (c) periodic stresses at steady-state due to tissue micromotion around the probe. We fabricated poly- dimethylsiloxane (PDMS) matrices with multi-walled carbon nanotubes (MWCNTs) using two distinct but carefully calibrated cross-linking ratios, resulting in hard (elastic modulus∼484 kPa) or soft, brain-like (elastic modulus∼5.7 kPa) matrices, the latter being at least 2 orders of magnitude softer than soft neural interfaces reported so far. Subsequent loading of the hard and soft silicone based matrices with (100% w/w) low-molecular weight PDMS siloxanes resulted in further decrease in the elastic modulus of both matrices. Carbon probes with soft PDMS coating show significantly less maximum axial forces (-587 ± 51.5 µN) imposed on the brain than hard PDMS coated probes (-1,253 ± 252 µN) during and after insertion. Steady-state, physiological micromotion related stresses were also significantly less for soft- PDMS coated probes (55.5 ± 17.4 Pa) compared to hard-PDMS coated probes (141.0 ± 21.7 Pa). The penetrating microindentation technique is valuable to quantitatively assess the mechanical properties of neural interfaces in both acute and chronic conditions.

Three dimensional X-ray diffraction (3DXRD) microscopy is a powerful technique that provides crystallographic and spatial information of a large number, of the order of thousands, of crystalline grains in a sample simultaneously. A key component of every 3DXRD microscopy experiment is the near field detector that provides high resolution spatial information of the grains. In this work we present a novel design for a semi-transparent, 16 megapixel near field detector. As opposed to a typical single scintillator phosphor detector, this design, we call the Quad Near Field Detector, uses four quadrants. It has a total field of view is 5.3 mm x 5.3 mm with an effective pixel size of 1.3 µm x 1.3 µm. The detector’s relatively large field of view can be used to obtain higher order diffraction spots which we anticipate will lead to improved spatial resolution in grain reconstructions. The large field of view can also enable the detector to be positioned further from the sample, in this way increasing the working distance and enabling larger environmental cells for in-situ studies. Many alignment parameters can be resolved by careful mechanical design. For this reason a novel translation stage for focusing the microscopes was developed, tested, and implemented. The near field detector was calibrated and characterized at the Cornell High Energy Synchrotron Source. The operational feasibility of such a multi-plate detector demonstrated in this work paves the way for new technologies in instrumentation of 3DXRD microscopy.

Poly[(rac-lactide)-co-glycolide] (PLGA) is used in medicine to provide mechanical support for healing tissue or as matrix for controlled drug release. The properties of this copolymer depend on the evolution of the molecular weight of the material during degradation, which is determined by the kinetics of the cleavage of hydrolysable bonds. The generally accepted description of the degradation of PLGA is a random fragmentation that is autocatalyzed by the accumulation of acidic fragments inside the bulk material. Since mechanistic studies with lactide oligomers have concluded a chain-end scission mechanism and monolayer degradation experiments with polylactide found no accelerated degradation at lower pH, we hypothesize that the impact of acidic fragments on the molecular degradation kinetics of PLGA is overestimated. By means of the Langmuir monolayer degradation technique, the molecular degradation kinetics of PLGA at different pH could be determined. Protons did not catalyze the degradation of PLGA. The molecular mechanism at neutral pH and low pH is a combination of random and chainend-cut events, while the degradation under strongly alkaline conditions is determined by rapid chainend cuts. We suggest that the degradation of bulk PLGA is not catalyzed by the acidic degradation products. Instead, increased concentration of small fragments leads to accelerated mass loss via fast chain-end cut events. In the future, we aim to substantiate the proposed molecular degradation mechanism of PLGA with interfacial rheology.

The application of safeguards measures by the International Atomic Energy Agency (IAEA) involves analytical measurements of samples taken during inspections of nuclear facilities. Thus constant development and advancement of analytical techniques is required. For quality control purposes, the IAEA has implemented a dedicated project to enhance its analytical capabilities by producing tailor-made reference materials for the analysis of uranium isotope signatures in (single) particles.

To this end, a particle production set-up was developed and implemented at Forschungszentrum Juelich capable to produce uranium oxide microparticles which are intended to be used as (certified) reference materials for particle analysis methods. A step towards the certification process is the evaluation of consistency of the size distribution and homogeneity. A monodisperse particle size distribution as well as the single phase triuranium octoxide structure was confirmed using SEM, µ-XRD and µ-Raman spectroscopy, respectively. Analysis performed on single uranium oxide microparticles confirmed consistency of the uranium isotopic ratios in comparison to the initial precursor solutions. To improve the homogeneity and particle handling, the particles are transferred into suspensions, for which the stability was investigated with respect to dissolution.

Impulsively started external convection at microscale level is studied numerically in both planar and axisymmetric geometries. Using similarity transformation, the resulting coupled partial and non-linear ordinary differential equations are simultaneously solved by finite differences together with a well established ordinary differential equation solver, over a range of problem parameters. Rarefaction effects within the slip flow regime on the thermal boundary layer response, heat transfer rate and transition time when system experiences sudden changes in surface temperature are analyzed, and a comparison between sudden surface cooling and heating is presented. The results show that the thermal boundary layer thickness, heat transfer rate and the transition time is considerably influenced by the degree of rarefaction. The transition time tends to be less sensitive with increasing rarefaction. The velocity slip and temperature jump factors are found to have opposite effects on the transition time and the heat transfer rate, with the velocity slip factor having the most profound influence on these parameters.

Biomedical applications—prostheses, tissue engineering, drug delivery, and wound healing—demand increasingly sophisticated characteristics from the materials that come into contact with living systems in the laboratory and the clinic. With the development of microfluidics, there is an opportunity to create active biomaterials based on embedded microfluidic structures. These structures allow for control of the concentrations of soluble chemicals and hydrodynamic stresses within the material and at its interfaces, and thus allow one to tailor the environment experienced by the living tissue. In this article, we review initial efforts to develop these microfluidic biomaterials and present considerations regarding the required characteristics of the materials and of the microfluidic-mediated mass transfer. As specific examples, we present work toward microfluidic control of mass transfer in scaffolds for tissue engineering and in wound dressings.

Efficient and reliable particle separators and concentrators are needed to support a wide range of analytical functions including pathogen detection, sample preparation, high-throughput particle sorting, and biomedical diagnostics. The advent of lab-on-a-chip devices based on the phenomenon of dielectrophoresis offers advantages that can meet several of the challenges associated with cell sorting and detection. The majority of the devices presented in the scientific literature have used glass-based devices for these applications, but there has been recent activity that indicates that polymer-based devices can operate as effectively as their glass progenitors. Processing and operational advantages motivate the transition from glass and silicon to polymer microdevices: mechanical robustness, economy of scale, ease of thermoforming and mass manufacturing, and the availability of numerous innate chemical polymer compositions for tailoring performance. We present here a summary of the developments toward, and results obtained from, these polymeric dielectrophoretic devices in the selective trapping, concentration, and gated release of a range of biological organisms and particles.