Adults suffering from lower back pain often find the cause of pain is degenerative disc disease. While non-surgical treatment is preferred, spinal fusion and total disc replacement remain surgical options for the patient. Total disc replacement is an emerging and improving treatment for degenerative discs. This paper provides a review of lumbar disc replacement for treatment of lower back pain. The mechanics and configuration of the natural disc are first discussed, followed by an introduction of treatment methods that attempt to mimic these mechanics. Total disc replacement types, materials, and failure mechanisms are discussed. Failure mechanisms primarily involve biochemical reactions to implant wear, as well as mechanical incompatibility of the device with natural spine motion. Failure mechanisms include: osteolysis, plastic deformation of polymer components, pitting, fretting, and adjacent level facet and disc degeneration.

Nano- and microscale ZnO demonstrate robust antibacterial action, although the driving mechanisms remain undetermined. In this study for commercial ZnO nano-powders and home-grown ZnO microparticles of varying morphologies we probe the response to bacterial growth media in isolation and with Staphylococcus aureus bacteria. ZnO microparticles are synthesized via a controllable hydrothermal method and subjected to biological assays with varying microbial environments. Changes in the optoelectronic, structural and chemical properties of these crystals before and after such exposure are characterized utilizing temperature-dependent photoluminescence spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. This is done to evaluate the impact of surface-surface interactions in antibacterial assays and the role ZnO surface and morphological properties play in these processes. In our experiments various bacterial environments are employed to elucidate the effects of media interactions on the cytotoxic efficacy of ZnO. In particular, minimum inhibitory concentration assays with Staphylococcus aureus reveal that microscale particles exhibit antibacterial efficacy comparable to that of the nano-powders, indicating that intra-bacterial internalization is not necessary for antimicrobial action. In our studies we determine that the nature of structural and optoelectronic changes in ZnO depends on both the media type and the presence (or absence) of bacteria in these media. Further evidence is provided to support significant cytotoxicity in the absence of particle internalization in bacteria, further highlighting the role of surface and media interactions in this process.

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We studied room temperature phosphorescence of tryptophan (TRP) embedded in poly (vinyl alcohol) films. With UV (285 nm) excitation, the phosphorescence spectrum of tryptophan appears at about 460 nm. We also observed the TRP phosphorescence with blue light excitation at 410 nm, well outside of the S0→S1 absorption. This excitation reaches the triplet state of tryptophan directly without the involvement of the singlet excited state. The phosphorescence lifetime of tryptophan is in the sub-millisecond range. The long-wavelength direct excitation to the triplet state results in high phosphorescence anisotropy which can be useful in macromolecule dynamics study via time-resolved phosphorescence.

The ability to design, control, and synthesize a material surface with superhydrophobicity is of great interests in many engineering applications. Here, we report a cost-effective process to fabricate poly(vinylidene fluoride) (PVDF)/zirconium(IV) oxide (ZrO2) composites with superhydrophobicity. This is achieved by combining an antisolvent that induces phase separation, i.e., the precipitation of PVDF from the solution through a spray-on method on various liquids. The material surfaces possess wrinkled micron-sized beads which displayed superhydrophobicity in water without any chemical treatment. The process developed in this research presented a fast and simple approach in making hydrophobic surfaces.

In this study, solid-state solutions of yttrium orthovanadate-phosphate with varying concentrations of codopants (Eu 3+ , Bi 3+ ) have been obtained via coprecipitation. An ionic radii mismatch between V 5+ and P 5+ substituents is manifested in broad XRD lines. The sharpening of the XRD lines is observed with increasing bismuth ions concentration in the Eu 3+ codoped YV 0.5 P 0.5 O 4 matrix. The difference in the number of the Stark components for the 5 D 0 → 7 F J transitions indicates changes in the lattice and a number of possible Eu 3+ sites. A thorough, systematic spectroscopic analysis of YV 0.5 P 0.5 O 4 : x mol % Eu 3+ , y mol % Bi 3+ was conducted at room temperature and 5 K. Metal-to-metal energy transfers occurring between Eu 3+ , V 5+ , and Bi 3+ optically active ions have been investigated. Additionally, efficiency of the Bi 3+ -Eu 3+ energy transfer (ET) was calculated.

Thermal nonradiative depopulation processes of excited levels significantly influence the potential application of phosphors. The high efficiency of thermal quenching of luminescence can limit a phosphor’s potential applications as well...

This research investigates hydrothermally synthesized hydroxyapatite nanoparticles doped with rubidium(I) and europium(III) ions. Investigation focused on establishing the influence of co-doped Eu3+ and Rb+ ions on hydroxyapatite lattice. Therefore, structural, and morphological properties were characterized via using X-ray powder diffraction (XRPD), infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM), as well as transmission electron microscopy (TEM) techniques. Furthermore, this investigation evaluates the impact of various Rb+ ion doping concentrations on the distinct red emission of co-doped Eu3+ ions. Hence, luminescence properties of the obtained materials were evaluated by measuring emission excitation, emission spectra, and luminescence decays. As established by numerous studies, synthetic hydroxyapatite has excellent application in biomedical field, as it is fully biocompatible. Its biocompatible makes it highly useful in the biomedical field as a bone fracture filler or hydroxyapatite coated dental implant. By the incorporation of Eu3+ ions and Rb+ ions we established the impact these co-doped ions have on the biocompatibility of hydroxyapatite powders. Therefore, biocompatibility toward a ram’s red blood cells was evaluated to exclude potential cytotoxic features of the synthesized compounds. Additionally, experimental in vitro bioactive properties of hydroxyapatite nanoparticles doped with Rb+ and Eu3+ ions were established using a mouse osteoblast model. These properties are discussed in detail as they contribute to a novel method in regenerative medicine.