Mexican-hat-like band dispersion is extremely critical to the realization of hole-doping-induced magnetism in monolayer metal monochalcogenides. However, it is absent from transition-metal dichalcogenides (TMDCs), i.e., WSe2. Herein, using first-principles calculations, we show that Mexican-hat-like band dispersion can be achieved by applying interlayer strain (ε) in the WSe2/SnS2 van der Waals (vdW) heterostructure when ε exceeds 15%. This is because in the strain-induced distorted trigonal prismatic crystal field, at the valence band edge, the W_dz2 orbitals shift upward around the Γ point, while the double-degenerate W_dxy/dx2-y2 orbitals shift downward at the K point, resulting in Mexican-hat-like band dispersion near the Γ point when the energy level of the Γ point surpasses that of the K point. On account of the appearance of the Mexican-hat-like band edge (MHBE), hole-doping in the strained WSe2/SnS2 heterostructure induces magnetization readily from the nonmagnetized phase. Our findings may provide a new strategy for the realization of magnetized TMDC-based vdW heterostructures.A novel strategy is developed to produce an FeS-FeNC-decorated hierarchical porous N,S-co-doped carbon (FeS-FeNC@NSC) electrocatalyst via introducing volatile FeCl3 into a porphyrin polymer framework followed by carbonization. The synergistic effect between the FeS nanoparticles and FeNC active sites in FeS-FeNC@NSC is beneficial for enhancing the ORR activity.Trace elements are essential for the normal spermatogenesis of mammals and play a critical role in sperm quality and pathological processes e.g. inflammation. Consequently, multi-elemental analysis of seminal plasma (SP) may provide significant information on physiological and pathophysiological processes occurring in the male reproductive tract. Therefore, the development of a simple, fast and reliable method for seminal plasma (SP) analysis by total reflection X-ray fluorescence spectrometry (TXRF) could be useful for both, scientific and clinical studies. In this study, a detailed assessment of the sample preparation parameters and measurement conditions, including analysis of the shape and element distribution of the deposited residue on the reflector by micro X-ray fluorescence spectrometry, was carried out. Using the best analytical conditions, limits of detection for trace elements were found to be in the range of 0.04-0.3 mg kg-1. Trueness and precision of the results, evaluated by spiked SP sample analysis, were in most cases acceptable with recovery values in the range of 87-109% and relative standard deviations 3-12% (n = 5). The developed TXRF method was applied for the analysis of several SP samples from patients with different diagnoses and the results were compared with those obtained by ICP-OES. Among the studied trace elements with a role in the antioxidant defence system only Zn could be quantified and some differences in Zn concentrations among studied groups were observed. However, further studies on a large number of samples are required to define the exact relationship between the element composition and semen quality.In this paper, a CO2-effervescence assisted dispersive micro solid-phase extraction procedure (CO2-EA-DμSPE) using a magnetic layered double hydroxide modified with polyaniline and a surfactant (Zn-Al-LDH-PA-DBSNa-Fe3O4) was applied for the pre-concentration of heavy metals (Ni2+, Pb2+, Co2+, and Cd2+). The final analysis of the analytes was carried out by atomic absorption spectroscopy. XRD, FTIR, and SEM studies were used for the characterization of the synthesized nanoadsorbent. For the maximum extraction efficiency, effective factors (including pH, nanoadsorbent dosage, and volume of the eluent) were investigated using the central composite design (CCD) method. Under the optimum conditions, the preconcentration factor was more than 20. The linear ranges for Ni2+, Pb2+, Co2+, and Cd2+ were obtained as (5-550), (7-750), (5-500), and (3-100) ng mL-1, respectively. The proposed method provided low detection limits (1.4, 2.1, 1.5, and 0.9 ng mL-1 for Ni2+, Pb2+, Co2+, and Cd2+, respectively) and suitable repeatability (relative standard deviation values (RSDs) below 6.1%, n = 6). Finally, the current method was successfully used for the extraction of heavy metals from cosmetic samples.Improvement in the performance of perovskite solar cells (PSC) and dye-sensitized solar cells (DSSC) upon modifications of mesoporous titania layers has been studied. For PSC with triple cation perovskite (FA0.76 MA0.19 Cs0.05 Pb (I0.81 Br0.19)3) about 40% higher photocurrent (up to ∼24 mA cm-2) was found for more homogenous, made of larger particles (30 nm) and thinner (150-200 nm) titania layer. For DSSC (both with liquid cobalt-based electrolyte as well as with solid state hole transporter – spiro-OMeTAD), a greater dye loading, rise in photovoltage, and the enhancement in relative photocurrent were observed for the cells prepared from the diluted titania paste (2  1 w/w ratio) with respect to those prepared from undiluted one. The impact of these improvements in titania layers on charge transfer dynamics in the complete solar cells as well as in pristine TiO2 layers was investigated by femtosecond transient absorption. Shorter photocarriers lifetime in perovskite material observed in better PSC, indicated that faster electron transfer at the titania interface was responsible for the higher photocurrent. Moreover, the photoinduced changes close to TiO2 interface were revealed in better PSC, which may indicate that in the efficient devices halide segregation takes place in perovskite material. In liquid DSSC, the fast component of unwanted recombination was slower in the samples with the diluted titania paste than in those made with undiluted ones. In solid state DSSC, hole injection from MK2 dye to spiro-OMeTAD takes place on the very fast ps time scale (comparable to that of electron injection) and the evidence of better penetration of spiro-OMeTAD into thinner and more porous titania layers was provided.Halogen-halogen bonded haloamine trimers serve as model systems for the X3 synthon present in numerous crystal structures and in two-dimensional self-assembled nanoarchitectures. Halogen bonds forming the synthon are often considered to display cooperativity. Synergy effects were previously found for halogen-halogen bonded bromoamine and iodoamine tetramers. In the present study comparison between haloamine cyclic trimers and tetramers is made. The cooperativity occurring in bromoamine and iodoamine clusters is significantly weaker in the case of the trimers. The present study demonstrates that the bromoamine and iodoamine trimers display weaker cooperativity due to a smaller number of synergy components in comparison to the corresponding tetramers of stronger cooperativity. LJC 11036 Moreover, the halogen-halogen interactions in bromoamine and iodoamine dimers with the geometries of the corresponding trimers and tetramers are examined using energy decomposition analysis methods (supermolecular, canonical EDA and SAPT) and the Kohn-Sham molecular orbital model.