Synthetic extracellular matrices and astrocytes provide a supportive microenvironment for the cultivation and investigation of primary pediatric gliomas.

Background: Pediatric gliomas comprise a diverse set of brain tumor entities that have substantial long-term ramifications for patient survival and quality of life. However, the study of these tumors is currently limited due to a lack of authentic models. Additionally, many aspects of pediatric brain tumor biology, such as tumor cell invasiveness, have been difficult to study with currently available tools. To address these issues, we developed a synthetic extracellular matrix (sECM)-based culture system to grow and study primary pediatric brain tumor cells. Methods: We developed a brain-like sECM material as a supportive scaffold for the culture of primary, patient-derived pediatric glioma cells and established patient-derived cell lines. Primary juvenile brainstem-derived murine astrocytes were used as a feeder layer to support the growth of primary human tumor cells. Results: We found that our culture system facilitated the proliferation of various primary pediatric brain tumors, including low-grade gliomas, and enabled ex vivo testing of investigational therapeutics. Additionally, we found that tuning this sECM material allowed us to assess high-grade pediatric glioma cell invasion and evaluate therapeutic interventions targeting invasive behavior. Conclusion: Our sECM culture platform provides a multipurpose tool for pediatric brain tumor researchers that enables both a wide breadth of biological assays and the cultivation of diverse tumor types.

Graphene-like Carbon from Calcium Hydroxide.

The development of inexpensive and environmentally friendly graphene-like carbon is critical for its integration into industrial products. This work highlights the production of graphene-like carbon structures from calcium hydroxide. The chemical vapor deposition conditions to grow graphitic carbon on a calcium hydroxide catalyst are reported. Acetylene, steam, and calcium hydroxide are used to grow a crumpled carbon morphology. The crumpled carbon resulted in a high surface area of 1276 m2/g and high electrical conductivity (>105 S/m). Additionally, the significance and origin of the C 1s X-ray photoelectron spectroscopy (XPS) π-π* plasmon loss peak as it is related to high electrical conductivity is reported. A unique mechanism for the catalytic process involving calcium acetylide is proposed. Several deposition times, steam concentration, and catalyst morphology were tested to synthesize a variety of carbon morphologies from calcium-based materials. Crumpled carbon, hollow nanospheres, bamboo-like carbon nanotubes, multi-walled carbon nanotubes, and graphene fiber morphologies were all formed using calcium-based catalysts. Multiple reaction conditions, a scaled reaction (300 g), and catalyst recyclability were investigated. Calcium-based materials were then used as catalysts for the growth of other graphene-like carbons.

Critical Rare Earth Element Recovery from Coal Ash Using Microsphere Flower Carbon.

There is a need to develop new solid-phase adsorbents to extract elements from the coal ash. High surface area carbon adsorbents are remarkably good at adsorption of rare earth elements and have good stability in acidic media. A high surface area (1162 m2/g), surface-oxidized microsphere flower carbon (MFC-O) has been prepared for the extraction of rare earth elements as well as thorium and uranium. MFC-O exhibits outstanding distribution coefficients up to kd = 1.2 × 106 for thorium, uranium, and rare earth elements. It was found that thorium and uranium can be separated from the rare earth elements by adjusting the pH. The maximum extraction capacity (71.3 mg/g) was performed up to 88 ppm with 18 competitive elements (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, and U), and element recovery was >85%. A coal ash sample (NIST SRM 1633c) with a known concentration of elements (Na, Ca, Al, Si, Fe, Sc, La, Ce, Nd, Sm, Eu, Tb, Dy, Yb, Lu, Th, and U) was leeched resulting in 45% Ce recovery. The leeched solution from NIST 1633c was then mixed with MFC-O for Ce extraction of 74%, Na (17%), Ca (13%), Al (24%), Si (41%), and Fe (17%). The binding properties of MFC-O show that it is an attractive material for the selective extraction of rare earth elements from coal ash.

Selective Extraction of Thorium from Rare Earth Elements Using Wrinkled Mesoporous Carbon.

Liquid fluoride thorium reactors have been considered as replacements for uranium-based nuclear reactors, having many economic and environmental advantages. The production of thorium is usually accompanied by the separation of thorium from rare earth elements since the major thorium production mineral, monazite, contains other rare earth elements. The conventional manufacturing process involves a liquid-liquid extraction with organic ligands. There is a need to develop solid state absorbents with good reusability for metal ion separation processes. Porous carbon is particularly interesting due to acid/base resistance. A new absorbent, surface-oxidized wrinkled mesoporous carbon (WMC-O), has been prepared for the selective extraction of thorium ions from rare earth ions. WMC-O shows high selectivity for thorium adsorption due to the 4+ oxidation state of thorium. The distribution coefficient ( Kd) of the WMC-O for thorium from all rare earth elements is 2 orders of magnitude larger than that of surface-oxidized activated carbon (13 × 104 vs 35 × 102 at pH 2.15). WMC-O also shows a high adsorption capacity for pure rare earth ions ( Kd > 3 × 105). These features make WMC-O a promising absorbent for thorium extraction and rare earth ion recovery.