Promising performance of chemically exfoliated Zr-doped MoS2 nanosheets for catalytic and antibacterial applications

Nanostructured materials incorporated with biological reducing agents have shown significant potential for use in bactericidal applications. Such materials have also demonstrated considerable efficacy to counter effects of chemical toxicity. In this study, nanostructured molybdenum disulfide (MoS₂) was doped with various concentrations (2.5, 5, 7.5, 10 wt%) of zirconium (Zr) using a hydrothermal route in order to assess its antimicrobial and catalytic potential. Doped and control samples were characterized with various techniques. X-ray diffraction (XRD) analysis confirmed the presence of the hexagonal phase of MoS₂ and identification of various functional groups and characteristic peaks (Mo bonding) was carried out using FTIR spectra. Micrographs obtained from FESEM and HR-TEM showed a sheet-like surface morphology, while agglomeration of nanosheets was observed upon doping with nanoparticles. To seek further clarity regarding the layered features of S–Mo–S planes, the defect densities and electronic band structure of pure MoS₂ and doped MoS₂ samples were investigated through Raman analysis. Optical properties of Zr-doped MoS₂ nanosheets were assessed using a UV-vis spectrophotometer and the results indicated a red-shift, i.e., movement of peaks towards longer wavelengths, of the material. Dynamics of migration and recombination of excited electron–hole pairs were investigated using PL spectroscopy, which was also used to confirm the presence of exfoliated nanosheets. In addition, the synthetic dye degradation potential of pure and doped samples was investigated in the presence of a reducing agent (NaBH₄). It was noted that doped MoS₂ showed superior catalytic activity compared to undoped MoS₂. The nanocatalyst synthesized in this study exhibited enhanced antibacterial activity against E. coli and S. aureus at high concentrations (0.5, 1.0 mg/50 μl). The present study suggests a cost-effective and environmentally friendly material that can be used to remove toxins such as synthetic dyes and tannery pollutants from industrial wastewater.

Nanostructured materials incorporated with biological reducing agents have shown significant potential for use in bactericidal applications.     

Metal-ceramic screw-retained implant fixed partial denture with intraoral luted framework to improve passive fit

Passive fit of a long-span screw-retained implant prosthesis is an important criteria for the success of the restoration. This article describes a technique for fabricating a ceramometal implant fixed dental prosthesis (FDP) for a long-span partially edentulous situation by altering the conventional screw-retained design. The possibility of a passive fit is maximized by intraoral luting of the cast frame to milled abutments, and the potential framework distortion during fabrication is compensated to a major extent. Retrievability is ensured by screw retention of the prosthesis to the implants. Compared with conventional porcelain fused to metal screw-retained FDP, this prosthesis is relatively inexpensive to fabricate.     

In vitro suppression of programmed cell death of B cells by tissue inhibitor of metalloproteinases-1.

Cellular pathways for induction of programmed cell death (PCD) have been identified, but little is known about specific extracellular matrix processes that may affect apoptosis along those pathways. In this study, a series of Burkitt's lymphoma (BL) cell lines were assayed for their expression of tissue inhibitor of metalloproteinases (TIMP)-1. Results indicate that TIMP-1-positive BL lines show resistance to cold-shock-induced apoptosis. Furthermore, recombinant TIMP-1, but not TIMP-2 or a synthetic metalloproteinase inhibitor (BB-94), confers resistance to apoptosis induced by both CD95-dependent and -independent (cold shock, serum deprivation, and gamma-radiation) pathways in TIMP-1-negative BL lines. TIMP-1 suppression of PCD is not due to metalloproteinase inhibition, as reduction and alkylation of the TIMP-1 did not abolish this activity. Retroviral induction of TIMP-1 not only resulted in cell survival but also in continued DNA synthesis for up to 5 d in the absence of serum, while controls underwent apoptosis. This resistance to apoptosis is reversed by anti-TIMP-1 antibodies, demonstrating that secreted TIMP-1 is active in blocking apoptosis. Furthermore, TIMP-1 upregulation induced expression of Bcl-XL but not Bcl-2 as well as decreased NF-kappaB activity as compared with controls. These results demonstrate that TIMP-1 suppresses apoptosis in B cells and suggests a novel activity for TIMP-1 in tissue homeostasis.     

Detection of specific chromosomal aberrations in urine using BCA-1 (oligo-CGH-array) enhances diagnostic sensitivity and predicts the aggressiveness of non-muscle-invasive bladder transitional cell carcinoma

Introduction

Bladder carcinoma (B-TCC) is the fifth most prevalent carcinoma in the United States (US) or Europe. In addition, B-TCC is the most expensive carcinoma per patient between diagnosis and death, because of its 50–80 % recurrence rate. B-TCC is an optimal carcinoma for which to detect DNA alterations in urine, which is easily obtainable. Chromosomal aberrations in tumors have been closely related to the carcinogenesis process.

Material and Methods

We developed a highly specific and sensitive oligo-CGH-array for the diagnosis and follow-up of B-TCC, based on the detection of chromosomal aberrations in urine samples. One hundred and sixty-four urine samples were analyzed. The qualitative results, including chromosomal aberrations, were obtained. Quantitative results are expressed as a percentage of chromosomal alterations on the autosomes.

Results

From the urine samples, we were able to differentiate B-TCC from non-malignant conditions with an accuracy of 100 % for patients without history of B-TCC. For follow-up of B-TCC in clinical practice, at least a deletion (8p; 9p; 9q) or a cut-off of >2 % of chromosomal imbalance was considered as a positive test. According to our criteria, 100 % of high-grade tumors were diagnosed, and the sensitivity to predict positive cystoscopy was 95 % (specificity 73 %). A cut-off >9 % was a strong signature of high-grade TCC (odds ratio 53 CI 95 % 7–417; p = 0.0002).

Conclusion

We developed a sensitive clinical tool for the detection of B-TCC using DNA extracted from patient urine. This tool is also able to identify low-grade B-TCC and identify high-risk patients harboring a high-grade disease.     

Harvey Cushing's Early Operative Treatment of Skull Base Fractures

Objectives To review Dr. Harvey Cushing''s early surgical cases at the Johns Hopkins Hospital, revealing details of his operative approaches to fractures of the skull base. Design Following institutional review board approval and through the courtesy of the Alan Mason Chesney Archives, we reviewed the Johns Hopkins Hospital surgical files. Setting The Johns Hopkins Hospital, 1896 to 1912. Participants A total of 24 patients underwent operative treatment for suspected fractures of the skull base. Main Outcome Measures The main outcome measure was operative approach, postoperative mortality, and condition recorded at the time of discharge. Results Overall, 23 patients underwent operative treatment for suspected skull base fractures. The mechanisms of injury were known for 22 patients and included work-related injuries (41%), falls (23%), vehicle injuries (32%), and other trauma (5%). One patient had no mechanism of injury specified in the file. The outcome at the time of discharge from the hospital was “well” or “improved” in 12 patients (52%). The remaining 11 patients died during their admission. Conclusions Although Cushing''s experience with selected skull base pathology has been previously reported, the breadth of his contributions to operative approaches to the skull base has been neglected.     

Enhanced electrochemical response of a modified glassy carbon electrode by poly(2-vinlypyridine-b-methyl methacrylate) conjugated gold nanoparticles for detection of nicotine

Poly(2-vinylpyridine-b-methylmethacrylate) coated gold nanoparticles [P(2VP-MMA)-AuNPs] were prepared and characterized by UV-Vis, FTIR, AFM, and zetasizer analysis. Investigation of the potential of the synthesized poly(2-vinylpyridine-b-methylmethacrylate) coated gold nanoparticles [P(2VP-MMA)-AuNPs] for detection of nicotine is the main focus of the current study. P(2VP-MMA)-AuNPs were coated on a glassy carbon electrode (GCE) for electrochemical detection of nicotine by cyclic voltammetry. The effect of molar mass of individual P2VP blocks and total molar mass of the block copolymer is evaluated in the context of an enhanced electrochemical response of the modified GCE for its sensing ability of nicotine in both aqueous and organic media. The electrochemical detection of nicotine is significantly enhanced by modification of the GCE with P(2VP-MMA)-AuNPs.

Poly(2-vinylpyridine-b-methylmethacrylate) coated gold nanoparticles [P(2VP-MMA)-AuNPs] are employed for enhancement of electrochemical response of glassy carbon electrode for nicotine.