A concept for the biotechnological minimizing of emerging plastics, micro- and nano-plastics pollutants from the environment: A review.

Plastics, micro- and nano-plastics pollution are undoubtedly a severe and crucial ecological threat due to the durability of plastics and their destructive impacts on humans and wildlife. Most scientific investigations have addressed the classification, types, distribution, ingestion, fate, impacts, degradation, and various adverse effect of plastics. Heretofore, scanty reports have addressed implementing strategies for the remediation and mitigation of plastics. Therefore, in this paper, we review the current studies on the degradation of plastics, micro- and nano-plastics aided by microorganisms, and explore the relevant degradation properties and mechanisms. Diverse microorganisms are classified, such as bacteria, fungi, algae, cyanobacteria, wax worms, and enzymes that can decompose various plastics. Furthermore, bio-degradation is influenced by microbial features and environmental parameters; therefore, the ecological factors affecting plastic degradation and the resulting degradation consequences are discussed. In addition, the mechanisms underlying microbial-mediated plastic degradation are carefully studied. Finally, upcoming research directions and prospects for plastics degradation employing microorganisms are addressed. This review covers a comprehensive overview of the microorganism-assisted degradation of plastics, micro- and nano-plastics, and serves as a resource for future research into sustainable plastics pollution management methods.

Tenosynovial giant cell tumor of cruciate ligament: A case report and review.

INTRODUCTION: Tenosynovial giant cell tumor (TSGCT) is a slow-growing soft tissue tumor that develops from the synovial tissue of tendon sheaths, joints, or bursae. In the knee, this type of tumor is uncommon. Giant cell tumors of the cruciate ligaments' tendon sheath are far more infrequent. Only 16 localized TSGCTs of the cruciate ligaments have been recorded in the literature to our knowledge, with 9 involving the anterior cruciate ligament (ACL) and 7 involving the posterior cruciate ligament (PCL). CASE PRESENTATION: We present a rare case of localized TSGCT arising from the PCL's femoral insertion in a 44-year-old male, as well as a literature review on localized TSGCT of cruciate ligaments in the knee. The diagnosis of tumor's presence was made using MRI while the definitive diagnosis was obtained through intraoperative evaluation and postoperative pathology. CONCLUSION: Arthroscopic tumor resection was an effective and safe treatment option based on the available data.

Double Transition Metal Carbides MXenes (D-MXenes) as Promising Electrocatalysts for Hydrogen Reduction Reaction: Ab Initio Calculations.

Double-transition-metal MXenes (D-MXenes) have been widely pursued in the advancement of the renewable energy storage technology in recent years. In this work, the hydrogen evolution reaction (HER) catalytic mechanism of several oxygen-terminated D-MXenes with the chemical formula of M'2M″C2O2 (M' = Mo, Cr; M″ = Ti, V, Nb, Ta) is theoretically studied. For comparison, the corresponding monometallic MXenes (M-MXenes, M'3C2O2) are fairly compared by means of the density functional theory calculations. Based on our theoretical results, the HER performance of M-MXenes can be improved by constructing a "sandwich-like" ordered D-MXene configuration. Moreover, the HER performance of Mo-based D-MXenes (Mo2M″C2O2) is superior to that of Cr-based D-MXenes (Cr2M″C2O2), which highlights that the HER activity of Mo2VC2O2 and Mo2NbC2O2 is better than that of Pt(111). This work not only unravels the HER mechanism of D-MXenes (M'2M″C2O2) but also paves the way in designing emergent MXene-based HER electrocatalysts with high efficiency.

Novel Architecture Titanium Carbide (Ti3C2Tx) MXene Cocatalysts toward Photocatalytic Hydrogen Production: A Mini-Review.

Low dimensional transition metal carbide and nitride (MXenes) have been emerging as frontier materials for energy storage and conversion. Ti3C2Tx was the first MXenes that discovered and soon become the most widely investigated among the MXenes family. Interestingly, Ti3C2Tx exhibits ultrahigh catalytic activity towards the hydrogen evolution reaction. In addition, Ti3C2Tx is electronically conductive, and its optical bandgap is tunable in the visible region, making it become one of the most promising candidates for the photocatalytic hydrogen evolution reaction (HER). In this review, we provide comprehensive strategies for the utilization of Ti3C2Tx as a catalyst for improving solar-driven HER, including surface functional groups engineering, structural modification, and cocatalyst coupling. In addition, the reaming obstacle for using these materials in a practical system is evaluated. Finally, the direction for the future development of these materials featuring high photocatalytic activity toward HER is discussed.

Electronic structure manipulation of graphene dots for effective hydrogen evolution from photocatalytic water decomposition.

This paper presents a heteroatom doping strategy to manipulate the structure of graphene-based photocatalysts for effective hydrogen production from aqueous solution. Oxygenation of graphene creates a bandgap to produce semiconducting graphene oxide, nitrogen doping extends the resonant π-conjugation to prolong the charge lifetime, and sulfur doping breaks the electron neutrality to facilitate charge transfer. Accordingly, ammonia-treated sulfur-nitrogen-co-doped graphene oxide dots (A-SNGODs) are synthesized by annealing graphene oxide sheets in sulfur-ammonia, oxidizing the sheets into dots, and then hydrothermally treating the dots in ammonia. The A-SNGODs exhibit a high nitrogen content in terms of quaternary and amide groups that are formed through sulfur-mediated reactions. The peripheral amide facilitates orbital conjugations to enhance the photocatalytic activity, whereas the quaternary nitrogen patches vacancy defects to improve stability. The simultaneous presence of electron-withdrawing S and electron-donating N atoms in the A-SNGODs facilitates charge separation and results in reactive electrons. When suspended in an aqueous triethanolamine solution, Pt-deposited A-SNGODs demonstrate a hydrogen-evolution quantum yield of 29% under monochromatic 420 nm irradiation. The A-SNGODs exhibit little activity decay under 6-day visible-light irradiation. This study demonstrates the excellence of the heteroatom-doping strategy in producing stable and active graphene-based materials for photoenergy conversion.

Roles of nitrogen functionalities in enhancing the excitation-independent green-color photoluminescence of graphene oxide dots.

Fluorescent graphene oxide dots (GODs) are environmentally friendly and biocompatible materials for photoluminescence (PL) applications. In this study, we employed annealing and hydrothermal ammonia treatments at 500 and 140 °C, respectively, to introduce nitrogen functionalities into GODs for enhancing their green-color PL emissions. The hydrothermal treatment preferentially produces pyridinic and amino groups, whereas the annealing treatment produces pyrrolic and amide groups. The hydrothermally treated GODs (A-GODs) present a high conjugation of the nonbonding electrons of nitrogen in pyridinic and amino groups with the aromatic π orbital. This conjugation introduces a nitrogen nonbonding (nN 2p) state 0.3 eV above the oxygen nonbonding state (nO 2p state; the valence band maximum of the GODs). The GODs exhibit excitation-independent green-PL emissions at 530 nm with a maximum quantum yield (QY) of 12% at 470 nm excitation, whereas the A-GODs exhibit a maximum QY of 63%. The transformation of the solvent relaxation-governed π* → nO 2p transition in the GODs to the direct π* → nN 2p transition in the A-GODs possibly accounts for the substantial QY enhancement in the PL emissions. This study elucidates the role of nitrogen functionalities in the PL emissions of graphitic materials and proposes a strategy for designing the electronic structure to promote the PL performance.

Microstructural, electrical, and mechanical properties of graphene films on flexible substrate determined by cyclic bending test.

Three kinds of graphene/polyimide specimen were prepared via transfer with 3, 6, and 9 graphene layers, respectively. A self-designed bending tester was applied to carry out cyclic bending tests with various bending cycles and bending frequencies. The variations of electrical resistance of the specimens during the bending process and the rate of increase of electrical resistance with the number of bending cycles and bending frequency for various total graphene thicknesses were determined. The voids that form at the interfaces between any two adjacent layers increase in size, leading to a disconnection between graphene layers after a number of bending cycles. A reduction in the graphene thickness and increases in the number of bending cycles and bending frequency increase the rate of increase of electrical resistance. For specimens with a given graphene thickness, the ID/IG value of the Raman shift increases exponentially with increasing number of bending cycles and bending frequency. An increase in ID/IG is accompanied by increases in both the rate of increase of electrical resistance and the aspect ratio L1/L2 (where L1 and L2 are the half lengths of the long and short axes, respectively, of the selected-area electron diffraction pattern of graphene). The tilt angle formed in the top graphene layer of the specimen after bending tests increases with increasing graphene thickness for a given bending frequency. The rate of increase of the tilt angle is affected by the bending frequency.