Effect of geochemical properties on degradation of trichloroethylene by stabilized zerovalent iron nanoparticle with Na-acrylic copolymer.

Stable nanoscale zero-valent iron (NZVI) particles have been developed to remediate chlorinated compounds. The degradation kinetics and efficiency of trichloroethylene (TCE) by a commercial stabilized NZVI with Na-acrylic copolymer (acNZVI) were investigated and compared with those by laboratory-synthesized NZVI and carboxymethyl cellulose (CMC)-stabilized NZVI particles. Results show that the degradation of TCE by acNZVI was faster than that by NZVI and CMC-NZVI. Increase in temperature enhanced the degradation rate and efficiency of TCE with acNZVI. The activation energy of TCE degradation by acNZVI was estimated to be 23 kJ/mol. The degradation rate constants of TCE decreased from 0.064 to 0.026 min(-1) with decrease in initial pH from 9.03 to 4.23. Common groundwater anions including NO3(-), Cl(-), HCO3(-), and SO4(2-) inhibited slightly the degradation efficiencies of TCE by acNZVI. The Na-acrylic copolymer-stabilized NZVI, which exhibited high degradation kinetics and efficiency, could be a good remediation agent for chlorinated organic compounds.

The thermal degradation and soil recovery of thermal treatment of field-weathered decabrominated diphenyl ether-contaminated soil.

A farm at Taoyuan in Taiwan was highly contaminated with decabrominated diphenyl ether (BDE-209), a widely used commercial brominated flame retardant and persistent in the environment, more than 10 years. Since crops are able to absorb and accumulate BDE-209 from soils in our previous research, posing a hazardous risk for humans, it is essential to develop a practical method of soil treatment. Thermal treatment was studied among different approaches. In our previous study (Ko et al., 2022), we found that heating to 450 °C for 30 min achieved a complete removal of BDE-209 in soil. However, the high temperature significantly decreased the original soil organic matter (SOM) from 2.47% to 0.27%, altering the soil texture, damaging microbial biomass, and thus affecting the revegetation after the thermal treatment. Sugarcane bagasse, a common agricultural residue, served as an amendment to restore soil fertility. Current results indicate that 2.5% bagasse can improve the SOM in soil by up to 2.73% and restore its bacterial composition, making the plant growth conditions similar to those of the untreated contaminated soil. In light of the high removal efficiency provided by the 450°C-thermal treatment and the high recovery efficiency of sugarcane bagasse, the strategy presented in this study serves to be a promising method for sustainable remediation.

Posterior transarticular screw fixation for chronic atlanto-axial instability.

Treatment for chronic atlanto-axial instability remains problematic despite recent innovations in new surgical techniques and instrumentation. Our team reviewed a series of 23 cases of patients with chronic atlanto-axial instability who underwent posterior transarticular screw fixation operations between May 1998 and September 2002. Etiologies of these patients included failed prior surgery, rheumatoid arthritis, congenital anomalies and old odontoid fractures. The clinical presentations were nuchal pain and cervical myelopathy or radiculopathy, with sensory and/or motor deficits that persisted for more than 3 months. We routinely used external reduction to realign the C1-C2 axis prior to operating, and operated on patients using halo-vest fixation. After surgery, the halo-vest was replaced by a collar. In the post-operative follow-up, 22 of the 23 patients (96%) were found to have achieved solid, bony or fibrous union of the C1-C2 axis. Eleven of the 14 (79%) patients with pre-operative neck pain experienced immediate relief or significant improvement. Thirteen of the 20 patients (65%) with myelo-radiculopathy demonstrated improvement of previous motor deficits. Major morbidity included a vertebral artery (VA) injury and a malpositioned screw. No cases of mortality or neurological complications occurred in this series. Posterior transarticular C1-C2 screw fixation results in a high fusion rate without the additional need for rigid external immobilization. It allows good neurological recovery in cases of chronic atlanto-axial instability. Judicious pre-surgical planning and meticulous operative technique may avoid neurological complications and vertebral artery injury.

Degradation of polyurethane by bacterium isolated from soil and assessment of polyurethanolytic activity of a Pseudomonas putida strain.

The increasing usage and the persistence of polyester polyurethane (PU) generate significant sources of environmental pollution. The effective and environmental friendly bioremediation techniques for this refractory waste are in high demand. In this study, three novel PU degrading bacteria were isolated from farm soils and activated sludge. Based upon 16S ribosomal RNA gene sequence blast, their identities were determined. Particularly robust activity was observed in Pseudomonas putida; it spent 4 days to degrade 92% of Impranil DLN(TM) for supporting its growth. The optimum temperature and pH for DLN removal by P. putida were 25 °C and 8.4, respectively. The degradation and transformation of DLN investigated by Fourier transformed infrared spectroscopy show the decrease in ester functional group and the emergence of amide group. The polyurethanolytic activities were both presented in the extracellular fraction and in the cytosol. Esterase activity was detected in the cell lysate. A 45-kDa protein bearing polyurethanolytic activity was also detected in the extracellular medium. This study presented high PU degrading activity of P. putida and demonstrated its responsible enzymes during the PU degradation process, which could be applied in the bioremediation and management of plastic wastes.

Induction of dental pulp-derived induced pluripotent stem cells in the absence of c-Myc for differentiation into neuron-like cells.

BACKGROUND: A recent research breakthrough has demonstrated that the ectopic expression of four genes is sufficient to reprogram human fibroblasts into inducible pluripotent stem cells (iPSCs). However, whether human dental pulp cells (DPCs) could be reprogrammed into iPSCs remains an open question. In this study, we demonstrated that DPCs from deciduous and permanent teeth can be reprogrammed into iPSCs without c-Myc and had the capacity to differentiate into neuron-like cells. METHODS: DPCs were obtained from donors and reprogrammed into iPSCs using retroviral transduction with SOX2, OCT4, and KLF4. Then, these iPSCs were differentiated into neuron-like cells. Microarray and bioinformatics were used to compare the gene expression profile among these iPSCs and iPSC-derived neuron-like cells. RESULTS: The DPCs displayed a high vitality and capability to quickly restart proliferation and expressed elevated pluripotency similar to mesenchymal stem cells. According to our results, DPC-derived iPSC colonies that could be subcultured and propagated were established as early as 10 days after transduction, in comparison with the skin fibroblast (DPC-derived iPSCs) without c-Myc presented embryonic stem cell-like properties and the pluripotent potential to differentiate into neuron-like cells, which resemble neurons both morphologically and functionally. CONCLUSION: The human DPCs from deciduous and permanent teeth can undergo reprogramming to establish pluripotent stem cell lines without c-Myc. These surgical residues, usually regarded as medical waste, can be used as an alternative source of pluripotent stem cells for personalized medicine.

Inhibition of cancer stem cell-like properties and reduced chemoradioresistance of glioblastoma using microRNA145 with cationic polyurethane-short branch PEI.

Glioblastomas (GBMs) are the most common primary brain tumors with poor prognosis. CD133 has been considered a putative marker of cancer stem cells (CSCs) in malignant cancers, including GBMs. MicroRNAs (miRNAs), highly conserved small RNA molecules, may target oncogenes and have potential as a therapeutic strategy against cancer. However, the role of miRNAs in GBM-associated CSCs remains mostly unclear. In this study, our miRNA/mRNA-microarray and RT-PCR analysis showed that the expression of miR145 (a tumor-suppressive miRNA) is inversely correlated with the levels of Oct4 and Sox2 in GBM-CD133(+) cells and malignant glioma specimens. We demonstrated that miR145 negatively regulates GBM tumorigenesis by targeting Oct4 and Sox2 in GBM-CD133(+). Using polyurethane-short branch polyethylenimine (PU-PEI) as a therapeutic-delivery vehicle, PU-PEI-mediated miR145 delivery to GBM-CD133(+) significantly inhibited their tumorigenic and CSC-like abilities and facilitated their differentiation into CD133(-)-non-CSCs. Furthermore, PU-PEI-miR145-treated GBM-CD133(+) effectively suppressed the expression of drug-resistance and anti-apoptotic genes and increased the sensitivity of the cells to radiation and temozolomide. Finally, the in vivo delivery of PU-PEI-miR145 alone significantly suppressed tumorigenesis with stemness, and synergistically improved the survival rate when used in combination with radiotherapy and temozolomide in orthotopic GBM-CD133(+)-transplanted immunocompromised mice. Therefore, PU-PEI-miR145 is a novel therapeutic approach for malignant brain tumors.

Endoscopic transnasal transclival odontoidectomy: a new approach to decompression: technical case report.

OBJECTIVE: Endoscopic transnasal transclival resection of the odontoid process is less invasive than the standard transoral odontoidectomy. In this article, we describe our techniques, which are less invasive but provide successful decompression. CLINICAL PRESENTATION: From September 2004 to April 2007, three consecutive patients with basilar invagination and instability in the craniovertebral junction were enrolled. The causes for the invagination and instability included rheumatoid arthritis in two patients and trauma in one patient, and all patients presented with myelopathy and quadriparesis before intervention. INTERVENTION: All three patients underwent an endoscopic transnasal transclival approach for anterior decompression and resection of the displaced odontoid process and pannus to decompress the underlying medulla. Subsequently, they received occipitocervical fixation by lateral mass screws and bone fusion to ensure stability. Remarkable neurological recovery was observed after surgery in all patients, and no adverse effects were noted. CONCLUSION: Compared with the standard transoral approach, the transnasal transclival endoscopic approach for decompressing basilar invagination is a feasible and effective alternative that avoids common disadvantages like prolonged intubation, excessive tongue retraction, and the need for palatal incision.