Enhanced capacitive deionization properties of activated carbon doped with carbon nanotube-bridged molybdenum disulfide

The shortage of freshwater supplies has restricted societal development. Capacitive deionization (CDI) is an emerging technology for desalination of seawater or brackish water, the performance of which is highly dependent on electrode materials. In this work, a molybdenum disulfide/carbon nanotube composite (CNTs-b-MoS₂) with high capacitance was successfully synthesized using a hydrothermal method. The composite exhibited a specific capacitance of 112.79 F g^-1. To reduce costs and determine the practicality of using CNTs-b-MoS₂ for CDI, we combined activated carbon (AC) with CNTs-b-MoS₂ as a CDI electrode. The research demonstrated that after doping with 5% (mass ratio) CNTs-b-MoS₂, the specific capacitance and electrosorption capacity of AC were significantly improved and the maximum desalination capacity of CNTs-b-MoS₂/AC reached 8.19 mg g^-1. The low dosage of CNTs-b-MoS₂ combined with the high specific surface area of AC avoided the shortcomings of CNTs-b-MoS₂, namely low specific surface area and high cost. Moreover, the outstanding conductivity of CNTs-b-MoS₂ improved the conductivity and enhanced the adsorption capacity of AC, giving CNTs-b-MoS₂/AC potential as an advanced, low-cost CDI electrode material.

Thiazole Imide-Based All-Acceptor Homopolymer with Branched Ethylene Glycol Side Chains for Organic Thermoelectrics

n-Type semiconducting polymers with high thermoelectric performance remain challenging due to the scarcity of molecular design strategy, limiting their applications in organic thermoelectric (OTE) devices. Herein, we provide a new approach to enhance the OTE performance of n-doped polymers by introducing acceptor-acceptor (A-A) type backbone bearing branched ethylene glycol (EG) side chains. When doped with 4-(2,3-dihydro-1,3-dimethyl-1H-benzimidazol-2-yl)-N,N-dimethylbenzenamine (N-DMBI), the A-A homopolymer PDTzTI-TEG exhibits n-type electrical conductivity (σ) up to 34 S cm^-1 and power factor value of 15.7 μW m^-1  K^-2 . The OTE performance of PDTzTI-TEG is far greater than that of homopolymer PBTI-TEG (σ=0.27 S cm^-1 ), indicating that introducing electron-deficient thiazole units in the backbone further improves the n-doping efficiency. These results demonstrate that developing A-A type polymers with EG side chains is an effective strategy to enhance n-type OTE performance.

Doping and sports endocrinology: anabolic-androgenic steroids

The use of anabolic steroids affects not only professional athletes but also the general population (bodybuilders, gym clients, and adolescents). In the first case, its use is prohibited and sanctioned by the World Anti-Doping Agency and Olympic committees. For the other users, it is difficult to establish its prevalence since many obtain the products via the internet. The reasons for its use are varied and different forms of use and other types of users have been described. Among the side effects of steroid use, hypogonadism is the most frequent cause for endocrinological consultation. After a general introduction to doping, this review describes the historical background of anabolic-androgenic steroids, their classification, forms of use, physiological effects, adverse effects on different organs and systems, treatment of hypogonadism, as well as detection methods.

Does Hypoxia and Stress Erythropoiesis Compromise Cardiac Function in Healthy Adults? A Randomized Trial

OBJECTIVES

To investigate whether recombinant human erythropoietin (rHuEPO) injections during an altitude training camp impact heart function.

METHODS

Thirty (12 women) moderately trained subjects stayed at 2320 m altitude for 4 weeks while training. Subjects were randomized to placebo (isotonic saline) or rHuEPO (20 IU/kg body weight) i.v. injections. Transthoracic echocardiography imaging was acquired 3 days after arrival to altitude and prior to the first placebo or rHuEPO injection as well as one day after the last rHuEPO injection three weeks later.

RESULTS

rHuEPO did not alter cardiovascular morphology parameters, systolic or diastolic function. In the placebo group, altitude exposure improved left ventricle (LV) systolic function due to an increased twist angle but rHuEPO had no additional effects. Pulmonary arterial systolic pressure was unaffected in either group. Notably, rHuEPO hampered LV untwist rate without affecting LV early filling.

CONCLUSION

rHuEPO provided during mild altitude exposure does not cause any major effects on heart function. The observed alteration in LV untwist induced by rHuEPO is unlikely to have a meaningful clinical effect. Trial Registration Registered on www.

CLINICALTRIALS

gov (NCT04227665).

An overview on recent progress in photocatalytic air purification: Metal-based and metal-free photocatalysis

Air pollution is becoming a distinctly growing concern and the most pressing universal problem as a result of increased energy consumption, with the multiplication of the human population and industrial enterprises, resulting in the generation of hazardous pollutants. Among these, carbon monoxide, nitrogen oxides, Volatile organic compounds, Semi volatile organic compounds, and other inorganic gases not only have an adverse impact on human health both outdoors and indoors, but have also substantially altered the global climate, resulting in several calamities around the world. Thus, the purification of air is a crucial matter to deal with. Photocatalytic oxidation is one of the most recent and promising technologies, and it has been the subject of numerous studies over the past two decades. Hence, the photocatalyst is the most reassuring aspirant due to its adequate bandgap and exquisite stability. The process of photocatalysis has provided many benefits to the atmosphere by removing pollutants. In this review, our work focuses on four main themes. Firstly, we briefly elaborated on the general mechanism of air pollutant degradation, followed by an overview of the typical TiO₂ photocatalyst, which is the most researched photocatalyst for photocatalytic destruction of gaseous VOCs. The influence of operating parameters influencing the process of photocatalytic oxidation (such as mass transfer, light source and intensity, pollutant concentration, and relative humidity) was then summarized. Afterwards, the progress and drawbacks of some typical photoreactors (including monolithic reactors, microreactors, optical fiber reactors, and packed bed reactors) were described and differentiated. Lastly, the most noteworthy coverage is dedicated to different types of modification strategies aimed at ameliorating the performance of photocatalysts for degradation of air pollutants, which were proposed and addressed. In addition, the review winds up with a brief deliberation for more exploration into air purification photocatalysis.

Accurate data prediction by fuzzy inference model for adsorption of hazardous azo dyes by novel algal doped magnetic chitosan bionanocomposite

A bionanocomposite comprising of magnetic chitosan doped with algae isolated from native habitat was fabricated and utilized as an efficient adsorbent for the removal of hazardous azo dyes, namely, Direct Red 31 (DR31) and Direct Red 28 (DR28). The algal doped magnetic chitosan (Alg@mCS) was comprehensively characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction analysis (XRD), and Brunauer-Emmett-Teller (BET). On the sorption of dyes, the influence of various process variables such as pH, adsorbent dosage, contact time, temperature, and initial dyes concentration were addressed. The adsorbent demonstrated maximal removal of DR31 and DR28 at pH 5 and 3, respectively. The maximum adsorption capacity of DR31 and DR28 was observed at Alg@mCS dose of 0.6 g L^-1 and 7 g L^-1 in 10 and 20 min, respectively. The Redlich Peterson isotherm model was shown to be appropriate for dye adsorption, indicating monolayer coverage of the dyes on the adsorbent surface (R² > 0.99). The adsorption process followed pseudo-second-order kinetics (R² > 0.99). Based on 320 experimental datasets from batch studies and interpolated data, adaptive neuro-fuzzy inference system (ANFIS) models were utilized to estimate dye elimination (percent). A number of parameters were calculated to validate the model's applicability. The Alg@mCS was proven to be a useful adsorbent for eliminating toxic and harmful azo dyes from aqueous solutions.

Impact of doping on the optoelectronic, electronic and nonlinear optical properties and on the reactivity of photochromic polymers containing styrylquinoline fragments: Hartree-Fock and DFT study

Hartree-Fock (HF) and Density Functional Theory (DFT) studies were conducted to assess the impact of potassium doping on the thermodynamic, optoelectronic, electronic and nonlinear optical properties and on the reactivity of photochromic polymers containing styrylquinoline fragments. Doping was carried out on the virgin monomer (M1) and on the derivative monomer (M2) with the nitro group NO2. Three doped monomers were investigated including, the monomer M3 obtained from M1 by substituting the H atom with a potassium, the monomer M4 by substituting two H atoms and the monomer M5 obtained from M2 by substituting the H atom. Findings proved that the use of potassium and the nitro group is an excellent process to improve the electronics properties of styrylquinoline virgin monomers. In fact, the energy gap decreases from 3.82 eV for M1 to 3.02 eV and to 2.92 eV for M3 and M4, respectively; while the decrease from 3.43 eV for M2 to 2.52 eV for M5 was observed, thus demonstrating the good semiconductor character of the obtained compounds with relevant applications in the manufacture of solar cells. Likewise, the fundamental gap decreases from 6.50 eV for M1 to 5.34 eV and to 4.62 eV for M3 and M4, respectively; while the decrease from 6.11 eV for M2 to 5.21 eV for M5 was observed; thus demonstrating an improvement in the reactivity of our doped monomers. In addition, potassium doping is an appropriate method to enhance optoelectronic properties of styrylquinoline virgin monomers. Thus, the refractive index of our doped monomers is greater than that of glass, which is a reference in optic and can be used under high electric fields of the order of 1.90 × 10 9 Vm-1 for monomer M4 up to 7.01 × 10 9 Vm-1 for M3 and to 10.89 × 10 9 Vm-1 for M5. Finally, the strong enhancement of the linear and nonlinear optical (NLO) properties that we observed leads us to conclude that these doped monomers can be appropriate candidates in devices requiring good NLO properties.

Doping with aromatase inhibitors and oestrogen receptor modulators in steroid users: Analysis of a forum to identify dosages, durations and adverse drug reactions

INTRODUCTION

Some users of anabolic androgenic steroids (AAS) secretly consume aromatase inhibitors (AI) and selective oestrogen receptor modulators (SERM). Cyber-forums can be potential sources of information. Our aim was to determine the cycles used, and to identify the adverse drug reactions (ADRs) experienced, reported in a bodybuilding forum.

METHOD

We collected discussions on a French forum for AAS users (MESO-Rx®), from January 2013 to 2019 on concerning clomiphene, tamoxifen, anastrozole, exemestane and letrozole were collected. Characteristics of the users, duration of cures, treatments, dosages, point of purchase and occurrence of ADRs were analysed.

RESULTS

Among the 1792 posts published on the forum, 845 concerned SERM and 571 concerned AI, i.e. 2180 drugs used (several cycles included concomitant consumption). Our population was exclusively male, with an average age of 28.2±6.3years, and had been practising weight training for 6.7±5.6years. The SERMs were mainly used to "revive the hypothalamohypophyseal axis" and the AIs to "fight against androgen aromatisation". The median treatment duration was 22 days for SERM, 70days for anastrozole, 84days for exemestane and 30days for letrozole, with a mean dose of 69mg/d for clomiphene, 22mg/d for tamoxifen, 0.4mg/d for anastrozole, 10mg/d for exemestane, 2mg/d for letrozole. The main way of obtaining these drugs was through the internet. 157 ADRs were identified: 95 for SERMs and 62 for AI. The most represented were acne, musculoskeletal, mood and reproductive disorders. Impaired quality of life (according to the patient) was described in 54% of the SERM posts and 26% of the AI posts.

CONCLUSIONS

Patient narratives posted on forums can be a useful tool in the context of doping, to better understand practices, motivations and possibly to bring up pharmacovigilance signals.

Zn-doping and oxygen vacancy effects on the reactivity and properties of monoclinic and tetragonal ZrO2: a DFT study

Zirconia oxide (ZrO₂) is a material that has aroused great interest in the scientific community for its general use in various technological applications, such as fuel cells, solar cells, electronic devices, catalysis, dental biomaterial and ceramics. When it is applied as a catalyst, the doping and vacancy effects of their crystalline phases are important properties to guide new developments. This work investigates tetragonal and monoclinic crystalline phases of the Zn-doped ZrO₂ by periodic density functional calculations. Changes in the electronic and acid-basic properties were performed by Bader charge analysis, the density of states calculations (DOS) and the projected density of states (PDOS). The formation of oxygen vacancies was also evaluated. The calculated oxygen vacancy formation energies indicate that it is much easier to generate oxygen vacancy in the Zn-doped ZrO₂ than in the pure material; in addition, oxygen vacancy formation is favored in the monoclinic phase. Bader charge analyses and projected density of states indicated that the doping of ZrO₂ with Zn creates more basic and acid sites. The most stable material is the Zn-doped 3-fold coordinated Zr atom of the m-ZrO₂, which can be used for future developments and applications.

Adsorption mechanisms of different toxic molecular gases on intrinsic C2N and Ti-C2N-V monolayer: a DFT study

Recently, the excessive emission of chemical toxic gases such as nitrogen trifluoride (NF₃), ammonia (NH₃), phosgene (COCL₂), and benzene (C₆H₆) has caused serious environmental problems. Adsorption of these chemical toxic gas molecules is a promising method to reduce environmental pollution. In this work, density functional theory (DFT) calculations are used to investigate the adsorption properties of these chemical toxic molecules on intrinsic C₂N and Ti-C₂N_-V monolayer. The results show that NF₃, NH₃, C₆H₆, and COCL₂ can all be adsorbed to the intrinsic C₂N monolayer with weak adsorption energy, while the adsorption properties of these gas molecules were greatly improved after doping Ti atom. The adsorption energy of NH₃, C₆H₆, COCL₂, and NF₃ increased from - 0.585, - 0.432, - 0.633, and - 0.362 eV to - 2.214, - 1.699, - 1.822, and - 0.799 eV, respectively, which increased by 2 ~ 4 times compared with that before doping. Besides, the results of the electron distribution, work function, the total density of states (TDOS), and the partial density of states (PDOS) analysis indicate that the doped Ti atom can be used as a bridge to connect the adsorbed molecules with the C₂N_-V monolayer, strengthen their interaction, and significantly improve the adsorption capacity. Therefore, Ti-doped C₂N_-V (Ti-C₂N_-V) monolayer is a promising adsorbent for the enrichment and utilization of harmful gases.

Prevalence of performance enhancing substance use among elite football players in two super league teams in Blantyre, Malawi

Background

Use of performance enhancing substances (PES) is common among athletes with a worldwide prevalence ranging from 5% to 31%. There has been little knowledge of PES use in African athletes with no available data for Malawian football players. This study aimed to determine the prevalence of PESs use among elite football players in two super league teams in Blantyre, Malawi.

Methods

This was a cross-sectional study conducted in two super league football teams in Blantyre, Malawi. A modified standard questionnaire obtained from the World Anti-Doping Agency (WADA) Social science research package was administered to collect data from a convenient sample of 43 elite football players on the characteristics of participants, prevalence of PESs use and reasons for using PES. Data were analysed using descriptive statistics and Chi-square test.

Results

Out of 86 eligible football players, 43 with a mean age of 24 ± 4 years participated in the study. Many players (60%) had secondary education as their highest level of education and most players (86%) had played football for more than five years. Out of 43 participants, 39 (91%) had been using PESs while four (9%) had never used PESs. Out of 13 substances, caffeine (77%), herbal products (40%), and energy bars (40%) were the commonly used PESs while cocaine (2%) was the least used substance among the players. Improving performance was the most common reason (81%) why participants were using PESs followed by increase in lean body mass (35%).

Conclusion

The prevalence of PESs use among elite football players in two super league teams in Blantyre, Malawi is high. The most used PES are caffeine, herbal products and energy bars. Participants mainly use PESs for improved performance in football. Therefore, awareness among elite football athletes and stakeholders on adverse health effects of PES use should be promoted.

The role of doping strategy in nanoparticle-based electrochemiluminescence biosensing

Doping plays a crucial role in electrochemiluminescence (ECL) due to the followings: (1) Modulation of electronic structure, alteration of the surface state of nanoparticles (NPs), providing effective protection from the surrounding environment, thereby leading to ECL emitters with exceptional properties including tunable spectra, high luminescence efficiency, low excitation potential, and good stability. (2) Employment of doped NPs as promising coreactant alternatives due to the presence of functional groups such as amines induced by NP doping. (3) Serving as novel co-reaction accelerators (CRAs) for ECL through doping induced high catalytic properties. (4) Behaving as excellent carriers to load ECL emitters, recognition elements, and catalysts due to doping-induced larger surface area, higher conductivity and better biocompatibility of NPs. As a consequence, doped NPs have aroused broad interest and found wide applications in various ECL sensing platforms. In this review, the current promising improvements, concepts, and excellent applications of doped NPs for ECL biosensing are addressed. We aim to bring to light the physicochemical characteristics of various doped NPs that endow them with appealing ECL performance, leading to diverse applications in biosensing.

Environmental application of chlorine-doped graphitic carbon nitride: Continuous solar-driven photocatalytic production of hydrogen peroxide

Solar-driven photocatalytic generation of H₂O₂ over metal-free catalysts is a sustainable approach for value-added chemical production. Here, we synthesized chlorine-doped graphitic carbon nitride (Cl-doped g-C₃N₄) through a solvothermal method to effectively produce H₂O₂ with a rate of 1.19 ± 0.06 µM min^-1 under visible light irradiation, which was improved by 104 times compared to pristine g-C₃N₄. Continuous net production of H₂O₂ was realized at a rate of 2.78 ± 0.10 µM min^-1 up to 54 h with isopropanol as the hole scavenger, whereas H₂O₂ production was only sustained for ~ 6 h without scavengers. Both molecular simulations and advanced spectroscopic characterizations elucidated that the Cl dopant increased the charge transfer rate, decreased the bandgap, and reduced the activation energy of the rate-limiting step of O₂ reduction, all of which favored H₂O₂ production. This work implemented a novel metal-free photocatalyst for sustainable H₂O₂ production and elucidated the mechanism for promoting H₂O₂ production that can guide future photoreactive nanomaterial design.

Highly selective and easily regenerated porous fibrous composite of PSF-Na2.1Ni0.05Sn2.95S7 for the sustainable removal of cesium from wastewater

The removal of ¹³⁷Cs from radioactive wastewater remains a huge challenge due to the interference of many coexisting ions. Several tin chalcogenides (X₂Sn₃Y₇, XNa, K; YTe, Se, S) were synthesized and screened for highly selective cesium removal from radioactive wastewater. It was found that Na₂Sn₃S₇ showed the best adsorption performance for low cesium concentrations. Especially after nickel doping, the adsorption capacity and thermal stability of the adsorbent were significantly enhanced. Its maximum adsorption capacity reached 436.72 mg·g^-1 within only 5 min and adsorption performance kept active in the pH range of 2-12. After being coated with a porous polysulfone (PSF) fiber, the developed PSF-Na_2.1Ni_0.05Sn_2.95S₇ was applied to natural complex water with cesium concentration of 17.58 mg·L^-1. The separation factors between Cs⁺ and competitive ions ranged from 625.21 to 13123.21. It is noteworthy that NaNO₃ was an efficient regenerating agent and can be easily separated from the CsNO₃ mixture for cyclic utilization. Remarkably, only 45 min in each cycle of adsorption and desorption toward cesium was realized, and the adsorption properties hardly decreased even after 50 consecutive cycles. The above advantages make the proposed material an excellent candidate for efficient Cs⁺ removal and enrichment from wastewater.

Electronic, non-linear optical, optoelectronic, and thermodynamic properties of undoped and doped bis (ethylenedithio) tetraselenafulvalene (BETS) (C10H8S4Se4) molecule: first study using ab initio investigation

We have performed the ab initio calculation of the undoped and doped molecules bis (ethylenedithio) tetraselenafulvalene (BETS). Carbone (C) atoms have been substituted by Boron (B) to investigate their effects on the electronic structure and nonlinear optical, optoelectronic, and thermodynamic properties of BETS molecule. The RHF and hybrid density functional theories (WB97XD, B3PW91, and B3LYP) methods were applied, using the cc-pVDZ basis set. We found that the energy gap (Egap) of the doped molecules are respectively 2.476 eV and 2.569 eV for C₈B₂H₈S₄Se₄ and C₇B₃H₈S₄Se₄ with B3LYP/cc-pVDZ basis set, lower than one of the undoped molecule (3.316 eV). The significant increase values of polarizability (˂α˃) and first order hyperpolarizability (β) of the doped compounds, especially in C₈B₂H₈S₄Se₄ (< α >  = 4.5315 × 10^-23 esu, β = 22,672.27 × 10^-33 esu and < α >  = 4.518 × 10^-23 esu, β = 23,657.43 × 10^-33 esu respectively for B3LYP and B3PW91) compared to those of the undoped molecule (< α >  = 4.3602 × 10^-23 esu, β = 1290.38 × 10^-33 esu, and < α >  = 4.518 × 10^-23 esu) show that the new molecules have a good nonlinear optical property. Results suggest that these molecules doped with boron are a potential candidate as semiconductors compounds and nonlinear optical materials.

Sulfur-Doped Quintuple [9]Helicene with Azacorannulene as Core

Herein, a hetero(S,N)-quintuple [9]helicene (SNQ9H) molecule with an azacorannulene core was synthesized, currently representing the highest hetero-helicene reported in the field of multiple [n]helicenes. X-ray crystallography indicated that SNQ9H includes not only a propeller-shaped conformer SNQ9H-1, but also an unforeseen quasi-propeller-shaped conformer SNQ9H-2. Different conformers were observed for the first time in multiple [n≥9]helicenes, likely owing to the doping of heteroatomic sulfurs in the helical skeletons. Remarkably, the ratio of SNQ9H-1 to SNQ9H-2 can be regulated in situ by the reaction temperature. Experimental studies on the photophysical and redox properties of SNQ9H and theoretical calculations clearly demonstrated that the electronic structures of SNQ9H depend on their molecular conformations. The strategy of introducing heteroatomic sulfurs into the helical skeleton may be useful in constructing various conformers of higher multiple [n]helicenes in the future.

Tunable dual cationic redox couples boost bifunctional oxygen electrocatalysis for long-term rechargeable Zn-air batteries

Efficient nonprecious bifunctional electrocatalysts toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are essential for improving the electrochemical performance of Zinc-air (Zn-air) batteries. Herein, we report a cobalt-doped Mn₂(OH)₃VO₃ catalyst prepared by facile hydrothermal method, and the ratios of cationic redox couples of catalysts were tuned with different Co doping amounts. The as-prepared Mn_1.8Co_0.2(OH)₃VO₃ (MnCoVO-1) catalyst achieves the highest ratio of (Mn³⁺Mn⁴⁺)/Mn²⁺ and Co³⁺/Co²⁺ redox couples which serve as ORR and OER active sites respectively, and exhibits the enhanced electrocatalytic performance. Furthermore, when employed as air-cathode catalyst for rechargeable Zn-air batteries, the MnCoVO-1 catalyst reveals a high power density (278 mW cm^-2), enhanced rate performance and outstanding long-term stability of over 270 h. This work demonstrates the Co-doped Mn₂(OH)₃VO₃ with optimized electronic structure by rational doping engineering can serve as a promising bifunctional catalyst for oxygen electrocatalysis and rechargeable Zn-air batteries.

Boosting the photocatalytic activation of molecular oxygen and photodegradation of tetracycline: The role of interfacial synergistic effect of cocatalyst and dopants

Utilizing reactive oxygen species (ROS), which are generated by the activation of molecular oxygen (O₂) in oxidation reaction, is a promising method for pollutant degradation. However, it is limited by the commonly low efficiency of O₂ activation and carrier separation. Herein, as a model system, Ag cocatalyst and Cl doping modified g-C₃N₄ (Ag/Cl-CN) was constructed to improve the ability of O₂ activation. Results showed that Ag/Cl-CN could effectively convert more O₂ into ROS than pristine g-C₃N₄ (CN), and individually decorated CN (Ag-CN and Cl-CN). A series of experiments and DFT calculations revealed that the deposition of Ag could promote charge separation resulting in more charges accumulated around O₂ and the introduction of Cl led to a stronger adsorption capacity for O₂. Therefore, due to the synergistic effect of Ag cocatalyst and Cl dopant, Ag/Cl-CN generated higher concentrations of O₂^- and displayed much better activity for photocatalytic degradation of tetracycline (TC) than CN, Ag-CN and Cl-CN.

Asymmetrically Doping a Platinum Atom into a Au38 Nanocluster for Changing the Electron Configuration and Reactivity in Electrocatalysis

It is an obstacle to precisely manipulate a doped heteroatom into a desired position in a metal nanocluster. Herein, we overcome this difficulty to obtain Pt₁ Au₃₇ (SCH₂ Ph^t Bu)₂₄ and Pt₂ Au₃₆ (SCH₂ Ph^t Bu)₂₄ nanoclusters via controllably doping Pt atoms into the kernels of Au₃₈ (SCH₂ Ph^t Bu)₂₄ . We reveal that asymmetrical doping of one Pt atom into either of the cores of Au₃₈ (SCH₂ Ph^t Bu)₂₄ elevates the relative energy of the HOMO (highest occupied molecular orbital) accompanied by one valence electron loss of Pt₁ Au₃₇ (SCH₂ Ph^t Bu)₂₄ , compared to Au₃₈ (SCH₂ Ph^t Bu)₂₄ with 14 electrons, while symmetrical doping of two Pt atoms into the cores of Au₃₈ (SCH₂ Ph^t Bu)₂₄ narrows the HOMO-LUMO gap (LUMO: lowest unoccupied molecular orbital) of Pt₂ Au₃₆ (SCH₂ Ph^t Bu)₂₄ with two valence electrons less. Consequently, Pt₁ Au₃₇ (SCH₂ Ph^t Bu)₂₄ shows an electron-spin-induced high activity for CO₂ electroreduction, whereas Pt₂ Au₃₆ (SCH₂ Ph^t Bu)₂₄ is least efficient and Au₃₈ (SCH₂ Ph^t Bu)₂₄ has a decent performance.

Electronic structure and optical properties of B-, N-, and BN-doped black phosphorene using the first-principles

The structural stability, electronic structure, and optical properties of BN-doped black phosphorene systems at different concentrations were investigated using a density generalized theory approach based on the first principles. BN-doped black phosphorene was found to be more stable than B and N atom doping. With the increase of doping concentration, the stability of the structure gradually decreases, and the structure of the system with 25% doping concentration is the most stable. The intrinsic and N-doped black phosphorenes are direct bandgap semiconductors, and B and BN doping make the black phosphorene change from direct bandgap to the indirect bandgap. The total density of states is mainly contributed by the p-state electrons of the B and P atoms, and the N atoms have a role in the local density of states with little contribution to the overall one. The black phosphorene undergoes charge transfer between the B and N atoms. The amount of charge transfer increases with the increase of doping concentration. The BN-doped black phosphorene system is blue-shifted at the absorption and reflection peaks compared to the intrinsic black phosphorene system. From the dielectric constant, it is found that the doped system is shifted towards higher energy at the highest peak, leading to an increase in the intensity of the electric field generated by light, which is beneficial to increase the efficiency of photovoltaic power generation. The photoconductivity decreases and shifts toward higher energy after doping, with the most pronounced performance at BN doping concentrations of 12.5% and 25%.

Anchoring Black Phosphorus Quantum Dots on Fe-Doped W18 O49 Nanowires for Efficient Photocatalytic Nitrogen Fixation

Herein, we demonstrate that the surface anchoring of black phosphorus quantum dots (BPQDs) and bulk iron-doping in W₁₈ O₄₉ nanowires significantly promotes the photocatalytic activity toward N₂ fixation into NH₃ . More specifically, a NH₃ production rate of up to 187.6 μmol g^-1  h^-1 could be achieved, nearly one order of magnitude higher than that of pristine W₁₈ O₄₉ (18.9 μmol g^-1  h^-1 ). Comprehensive experiments and density-functional theory calculations reveal that Fe-doping could enhance the reducing ability of photo-generated electrons by decreasing the work function and elevating the defect band (d-band) centers. Additionally, the surface BPQDs anchoring could facilitate the N₂ adsorption/activation owing to the increased adsorption energy and advantaged W-P dimer bonding-mode. Therefore, synergizing the surface BPQD anchoring and bulk Fe-doping remarkably enhanced the photocatalytic activity of W₁₈ O₄₉ nanowires for NH₃ production.

Unravelling capacity fading mechanisms in sodium vanadyl phosphate for aqueous sodium-ion batteries

Na₃V₂(PO₄)₃ (NVP), which is known as a sodium superionic conductor (NASICON), has been successfully developed as an excellent cathode material for sodium-ion batteries (SIBs). However, the capacity of NVP quickly fades when used in an aqueous electrolyte. Herein, the charge storage and capacity attenuation mechanisms of carbon-coated NVP (NVP@C) were carefully investigated by systematic material characterization and density functional theory (DFT) calculations. According to the results, protons in the aqueous electrolyte diffuse into the surface of NVP@C to occupy the sodium site and attack the nearby phosphates during the charge-discharge cycles, leading to the deformation and breakage of the POV bond. The distorted phosphates on the surface of NVP@C gradually dissolve into the electrolyte, causing a decrease in capacity. To stabilize the phosphates on the surface of NVP, DFT calculations suggest that iron doping of NVP can effectively relieve the deformation of the POV bond and suppress the capacity decay. The as-prepared Na₃V_1.5Fe_0.5(PO₄)₃@C (NV_1.5Fe_0.5P@C) has a capacity retention of 95% in the first ten cycles, while NVP@C retains only 55% of the initial capacity in the same number of cycles.

Fake anabolic androgenic steroids on the black market - a systematic review and meta-analysis on qualitative and quantitative analytical results found within the literature

OBJECTIVE

Supraphysiologic doses of anabolic androgenic steroids (AAS) are widely used to improve body image and sport performance goals. These substances can easily be acquired over the internet, leading to a substantial black market. We reviewed literature that assessed the quality and quantity of AAS found on the black market.

METHODS

We searched PubMed/Medline, Embase and Google Scholar for articles published before March 2022. Additional hand searches were conducted to obtain studies not found in the primary literature search. Studies were included if they report on qualitative and/or quantitative analytical findings of AAS from the black market. Primary outcomes were proportions of counterfeit or substandard AAS. Eligible articles were extracted; quality appraisal was done using the ToxRTool for in-vitro studies. We used random-effects models to calculate the overall mean estimates for outcomes. The review protocol has been published and registered in INPLASY.

RESULTS

Overall, 19 studies, which in total comprised 5,413 anabolic samples, met the inclusion criteria, and passed the quality appraisal from two WHO world regions that reported findings, the Americas and Europe. Most studies were nonclinical laboratory studies (95%) and provided samples seized by authorities (74%). In 18 articles, proportions of counterfeit substances and in eight articles, proportions of substandard substances were presented. The overall mean estimate for counterfeit anabolic steroids found on the black market was 36% (95% CI = 29, 43). An additional 37% (95% CI = 17, 63) were of substandard quality. We also demonstrate that these drugs could contain no active ingredient, or in another amount than that labeled, a wrong active ingredient, as well as not all or more active ingredients than were labeled. High heterogeneity among all analyses and significant differences between geographical subgroups were found.

CONCLUSION

With this systematic review and meta-analysis, we demonstrate that substantial mean proportions of black-market AAS are counterfeit and of substandard quality. These products pose a considerable individual and public health threat, and the very wide range in proportions of fake black-market AAS puts the user in a situation of unpredictable uncertainty. There is a great need for future prevention and harm-reduction programs to protect users from these substances.

Enhanced disinfection of E. faecalis and levofloxacin antibiotic degradation using tridoped B-Ce-Ag TiO2 photocatalysts synthesized by ecofriendly citrate EDTA complexing method

Since its use for photochemical water splitting reported first in 1972, TiO₂ is one of the most extensively studied photocatalysts for a diverse range of applications. Monodoping or codoping of the catalyst is a proven strategy to enhance the functionality of TiO₂ under solar or visible light. However, the use of three or more dopants in the development of more efficient and visible light active photocatalysts has not been investigated widely, especially for microbial disinfection. Boron/cerium/silver tridoped TiO₂ photocatalysts with curated amounts of the dopants (B = 1, 2 at.%, Ce = 0.1 at.%, Ag = 0.06 at.%), synthesized by the ecofriendly EDTA-citrate method, were evaluated for the disinfection of water using Enterococcus faecalis under UV-A irradiation and degradation of levofloxacin antibiotic under solar light. The catalyst characterization revealed that the spherical nanoparticles had a crystallite size of ~ 13 nm and bandgap energy values of 2.8-2.9 eV. 2B-0.1Ce-0.06Ag-TiO₂ is the best catalyst for microbial disinfection with a log reduction and kinetic rate constant ~ 30 and ~ 4.5 times higher than those values determined for the other codoped or monodoped catalysts, confirming an enhanced performance. Regarding levofloxacin degradation, the best performing catalyst is 1B-0.1Ce-0.06Ag-TiO₂ with degradation of 99% and 83% COD reduction in 100 min. The tridoped photocatalysts are very effective in the inactivation of Enterococcus faecalis, thus solving the problem of antimicrobial resistance in waters containing antibiotic residues.

B-doped SnO2 nanoparticles: a new insight into the photocatalytic hydrogen generation by water splitting and degradation of dyes

Boron-doped SnO₂ (B:SnO₂) has been synthesized via a facile wet chemical method to deal with increasing energy demand and environment-related issues. Powder XRD confirmed the rutile phase of the synthesized B:SnO₂ nanoparticles. Energy dispersive X-ray analysis and elemental mapping confirmed 1% B doping into SnO₂ lattice. A red shift was observed during the analysis of Raman and FTIR spectral data. The bands in FTIR and Raman spectra confirmed the in-plane and bridging oxygen vacancies in SnO₂ lattice introduced due to B doping. These nanoparticles showed proficiency in photocatalytic hydrogen generation and degradation of crystal violet (CV) and rhodamine B (RhB) dyes. The degradation of CV and RhB dyes in the presence of B:SnO₂ NPs and ethane-1,2-diaminetetracetic acid (EDTA) was found to be 83 and ~ 100%, respectively. To escalate the efficiency of dye degradation, the experiment was performed with different sacrificial agents (EDTA, methanol, and triethanolamine). The maximum hydrogen production rate (63.6184 µmol g^-1 h^-1) was observed for B:SnO₂ along with Pd as co-catalyst, and methanol and EDTA solution as sacrificial agents.