Efficient Photocatalytic Reduction of Hexavalent Chromium by BiVO4-Decorated MXene Photocatalysts and Their Charge Carrier Dynamics.

The synergistically MXene (Ti3C2Tx) co-catalyst-decorated BiVO4-based heterostructured photocatalysts have been synthesized by a hydrothermal approach with varied loading concentrations of MXene (Ti3C2Tx) to drive the hexavalent chromium reduction efficiently. The formation of the heterostructured photocatalyst was confirmed by the appearance of X-ray diffraction (XRD) peaks corresponding to the monoclinic BiVO4 phase and MXene (Ti3C2Tx) and also the antisymmetric (834 cm-1) and symmetric stretching (715 cm-1) of tetrahedral VO4 and D (1330 cm-1) and G (1570 cm-1) bands corresponding to MXene (Ti3C2Tx) in the Raman spectrum. The worm-like structures of BiVO4 nanocrystals grew onto the lamellar sheets of MXene (Ti3C2Tx), as shown by field emission scanning electron microscopy (FESEM), and has an increased surface area of 15.62 m2g-1 in the case of BVO-20-TC. X-ray photoelectron spectroscopy (XPS) analysis confirms the presence of V5+ and Ti3+states, and the uniform distribution of BiVO4 nanocrystals over lamellar sheets of MXene (Ti3C2Tx) is evident from energy-dispersive X-ray (EDX) analysis. The ultraviolet-diffuse reflectance spectroscopy (UV-DRS) spectra suggest a decrease in the band gap energy of BVO-20-TC to 2.335 eV, promoting a higher degree of visible light harvesting. Upon optimization, by varying the pH, the amount of the photocatalyst, and the concentration of Cr(IV), BVO-20-TC exhibits the highest photocatalytic efficiency (96.39%) while using a Cr(VI) concentration of 10 ppm at pH 2 and 15 mg of the photocatalyst, and the photoreduction of Cr(VI) to Cr(III) follows the pseudo-first-order reaction. The decrease in the PL intensity in BVO-20-TC reveals a faster transfer of electrons from MXene (Ti3C2Tx) to BiVO4. Further, the higher degree of band bending at the BiVO4/MXene (Ti3C2Tx) heterojunction, revealed from the Mott-Schottky analysis, facilitates efficient charge transfer and eventually faster and efficient photoreduction of Cr(VI) to Cr(III). The reusability and stability test undertaken for BVO-20-TC reveals that even after five cycles, the Cr (VI) photoreduction efficacy is retained. This work provides insights into photoreduction of Cr (VI) by using such heterostructures.

Factors affecting the incorporation of extracorporeally irradiated autograft for the treatment of bone tumours-a retrospective analysis from a tertiary referral centre.

PURPOSE: Re-implantation of the tumor bearing autograft following extracorporeal radiation therapy (ECRT) has been established as an oncologically safe biological reconstruction technique following resection of bone sarcomas. However, factors affecting the ECRT graft-host bone incorporation have not been fully investigated. An insight into the factors that influence graft incorporation can circumvent the complications and increase graft survival. METHODS: A total of 96 osteotomies in 48 patients with intercalary resections of primary extremity bone sarcomas (mean age 15.8 years, mean follow-up 42.1 months) were analyzed retrospectively for factors ECRT autograft-host bone union. RESULTS: On univariate analysis, age < 20 years, metaphyseal osteotomy site, V-shaped diaphyseal osteotomy, and use of additional plate at diaphyseal osteotomy had a significantly faster time to union, while gender, tumour type, bone involved, resection length, chemotherapy, type of fixation, and use of intra-medullary fibula did not influence union time. In multivariate analysis, V-shaped diaphyseal osteotomy and use of additional plate at diaphyseal ostetomy were the independent factors with favourable time to union. None of the analyzed factors was found to have a significant effect on the union rate. The major complications were non-union in 11.4% patients, graft failure in 2.1%, infection in 12.5%, and soft tissue local recurrences in 14.5% patients. CONCLUSION: Modified diaphyseal osteotomy and augmentation of the stability of the reconstruction using additional small plates enhance the incorporation of ECRT autograft.

Leaving half the acetabulum in pelvic resections improves hip function. Is there a need to revisit conventional pelvic resections?

BACKGROUND: Conventional periacetabular pelvic resections are associated with poor functional outcomes. Resections through surgical corridors beyond the conventional margins may be helpful in retaining greater function without compromising the oncological margins. METHODS: The study included a retrospective review of 82 cases of pelvic resections for pelvic tumors. Outcomes of acetabulum preservation (Group A) were compared with complete acetabular resection (Group B). Also, we compared outcomes of Type I + half resections (Group 1) with Type I + II resections (Group 2), and Type III + half resections (Group 3) with Type II + III resections (Group 4). RESULTS: Group A (n = 44) had significantly better functional outcome than Group B (n = 38) with average MSTS93 score 22.3 versus 20.1 and average HHS 91.3 versus 82.5 (p < 0.001). Group 1 (n = 14) and Group 2 (n = 12) had similar functional outcomes (mean MSTS93 score 22.07 vs. 21.58 [p = 0.597] and mean HHS 90.37 vs. 86.51 [p = 0.205]). Group 3 (n = 11) had significantly better functional outcome than Group 4 (n = 17), with mean MSTS93 score 22.8 versus 19.7 (p < 0.001) and mean HHS 92.3 versus 80.1 (p < 0.001). Oncological outcomes were similar among the groups. CONCLUSION: Transacetabular pelvic resections provide functional benefit over conventional resections without compromising oncological margins. There is a need to revisit and revise the pelvic resection planes.

Functional Outcomes of Centralization of the Ulna as a Method of Reconstruction Following Resection of Campanacci Grade 3 Giant Cell Tumor of the Distal Radius.

PURPOSE: Wrist reconstruction after distal radial tumor resection poses a challenge to the orthopedic oncologist. We evaluated the functional outcomes of centralization of the ulna with ulnocarpal arthrodesis as a method of reconstruction following resection of distal radius tumors, using impairment measures and patient-reported outcomes. METHODS: Evaluation of functional outcome was performed using the Musculoskeletal Tumor Society 93 scoring system and Disabilities of the Arm, Shoulder, and Hand questionnaire. We also determined hand grip strength on the affected side, time to radiologic union at the ulnocarpal junction and reduction in wrist circumference. Local complications and oncologic outcomes were recorded. RESULTS: The study included 26 patients with Campanacci grade 3 giant cell tumor of the distal radius. Mean follow-up period in the study was 32.8 ± 12 months. Mean resection length was 10.3 ± 2.5 cm. Radiologic union at the ulnocarpal junction was achieved in 38.5%, 77% and 96% of the patients by 4, 5, and 6 months respectively. Mean hand grip strength was 74 ± 3.9% of the contralateral side whereas mean reduction in wrist circumference was 16.9 ± 6.4%. A good functional outcome with a mean the Musculoskeletal Tumor Society 93 score of 26 ± 1.4 and mean Disabilities of the Arm, Shoulder, and Hand score of 10.5 ± 6.3 was observed. Fracture of the ulna, hardware loosening, and reflex sympathetic dystrophy were each noted in 1 patient, with an overall complication rate of 10.7% (3/28). No patient had nonunion, infection, or local recurrence. CONCLUSIONS: This is a simple and effective modality of reconstruction after resection of distal radial tumors. It provides good functional outcome and preservation of good hand grip strength, with low complication rates. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.