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77Se‐NMR is used to characterise several chalcogen bonded complexes of derivatives of the organoselenium drug ebselen, exploring a range of electron demand. NMR titration experiments support the intuitive understanding that chalcogen bond donors bearing more electron withdrawing substituents give rise stronger chalcogen bonds. The chemical shift of the selenium nucleus is also shown to move upfield as it participates in a chalcogen bond. Solid‐state NMR is used to explore chalcogen bonding in co‐crystals. Due to the lack of molecular reorientation on the NMR timescale in the solid state, the shape of the chemical shift tensor can be determined using this technique. A range of co‐crystals are shown to have extremely large chemical shift anisotropy, which suggests a strongly anisotropic electron density distribution around the selenium atom. A single crystal NMR experiment was conducted using one of the co‐crystals, affording the absolute orientation of the chemical shift tensor within the crystal. This showed that the selenium nucleus is strongly shielded in the direction of the chalcogen bond (due to the approach of the lone pair of the Lewis base), and strongly deshielded in the perpendicular direction. The orientation of the deshielded axis is consistent with the presence of a second σ‐hole which is not participating in a chalcogen bond, showing the profound effect of electron density anisotropy on the chemical shift. [ABSTRACT FROM AUTHOR]

Singlet fission (SF) is a potential avenue for augmenting the performance of silicon photovoltaics, but the scarcity of SF materials energy‐matched to silicon represents a barrier to the commercial realization of this technology. In this work, a molecular engineering approach is described to increase the energy of the S1 and T1 energy levels of diketopyrrolopyrrole derivatives such that the energy‐level requirements for exothermic SF and energy‐transfer to silicon are met. Time‐resolved photoluminescence studies show that the silicon‐matched materials are SF active in the solid state, forming a correlated triplet pair 1(TT) – a crucial intermediate in the SF process – as observed through Herzberg‐Teller emission from 1(TT) at both 77 K and room temperature. Transient electron paramagnetic resonance studies show that the correlated triplet pair does not readily separate into the unbound triplets, which is a requirement for energy harvesting by silicon. The fact that the triplet pair do not separate into free triplets is attributed to the intermolecular crystal packing within the thin films. Nevertheless, these results demonstrate a promising route for energy‐tuning silicon‐matched SF materials. [ABSTRACT FROM AUTHOR]

In this report, a microporous metal–organic framework of [Ca(TDC)(DMA)]n (1) and a two‐dimensional coordination polymer of [Ca(TDC)(DMF)2]n (2), (TDC2−=Thiophene‐2,5‐dicarboxylate, DMA=N, N'‐dimethylacetamide and DMF=N, N'‐dimethylformamide) based on Ca(II) were designed by the effect of solvent, and X‐ray analysis was performed for the single crystals of 1 and 2. Then, compound 1 was synthesized in three different methods and identified with a set of analyses. Compared to other adsorbents, MOFs are widely used in the field of adsorption and separation of various gases due to a series of distinctive features such as diverse and adjustable structures pores with different dimensions, high porosity and surface area with regular distribution of active sites. Therefore, the ability of 1 to uptake single gases (CH4, CO2, C2H2, H2, and N2) and separation of several binary mixtures of gases (CO2/CH4, CO2/N2, CO2/H2 and CO2/C2H2), were investigated using Grand Canonical Monte Carlo simulations. Volumetric and gravimetric adsorption isotherms in various operating conditions, the isosteric heat of adsorption (qst), the chemical potential for each thermodynamic state, and snapshots during the simulation process were reported in all cases. The results obtained from the adsorption simulation indicate that compound 1 has a high capacity for uptake of H2 (16 mmol g−1) and N2 (12.5 mmol g−1), CO2 (6.6 mmol g−1), C2H2 (5 mmol g−1) and CH4 (1.5 mmol g−1) gases at 1 bar. It also performs well in separating CO2 in binary mixtures, which can be attributed to the presence of open metal sites in nodes of 1 and their electrostatic tendency to interact with CO2 containing the higher quadrupole dipole moment compared to other components of the mixture. [ABSTRACT FROM AUTHOR]

Single‐crystal X‐ray diffraction studies for a variety of metal ion complexes of functionalised sarcophagines (sarcophagine=sar=3,6,10,13,16,19‐hexa‐azabicyclo[6.6.6]icosane) have further confirmed not only that the form of the metal ion/sar unit is unique for each metal, albeit with a sensitivity of the conformation to the associated counter anions, but also that for any given metal and ligand substituent, the dimensions (bond lengths and angles) of the complex and the substituent at the secondary nitrogen centres do not differ significantly from those of the isolated components. Despite this, where the substituent contains reactive sites, the reactivity differs markedly from that of their form in an uncoordinated substrate. Rationalisations are offered for these differences, in part through the use of Hirshfeld surface analysis of the intermolecular interactions. The kinetic inertness of the complexes means that the metal ions can be considered to act as regioselective protecting groups. [ABSTRACT FROM AUTHOR]

A new N2O2‐tetradentate Schiff base ligand entitled as N,N′‐((ethane‐1,2‐diybis [oxy])bis (ethan‐2,1‐diyl))bis(3‐(4‐methoxyphenyl)prop‐2‐en‐1‐imine was prepared by direct reaction between 3‐(4‐methoxyphenyl)‐2‐propenal and 1,8‐diamino‐3,6‐dioxaoctane. After characterization of the ligand, some novel cadmium coordination compounds formulated as CdLX2 (X: Cl−, Br−, I−, N3−, SCN−and NO3−) were synthesized and characterized by physical and spectral techniques. Typically crystal structure of cadmium nitrate coordination compound was determined suggesting crystallization in monoclinic system (with space group of I2/a) and a coordination geometry of square anti‐prism around the Cd (II) ion. Moreover, CdLBr2 and CdLI2 compounds were prepared in nanostructured dimensions by sonochemical method confirmed by SEM, EDX, and XRD techniques. In continuation, thermal behavior investigation of the compounds including thermal stabilities, thermal decomposition steps, and thermo‐kinetic parameters was performed based on Coats‐Redfern equations from room temperature to 900 °C. Furthermore, all the compounds were subjected to bioassay against two Gram‐positive bacteria of Staphylococcus aureus and Bacillus subtilis, two Gram‐negative bacteria of Pseudomonas aeruginosa and Escherichia coli, and two fungal strains of Aspergillus oryzae and Candida albicans. The results showed that all the synthesized compounds act well as antimicrobial agents. DNA cleavage power of the materials was also evaluated using extracted DNA from E. coli bacterium. The cytotoxic activities of some compounds were investigated against the prostate cancer cell lines (PC3) and human umbilical vein endothelial cells (HUVEC) (as normal cells) by MTT assay and nitric oxide level evaluation method as compared with cis‐platin confirming anti‐cancer effects of them. Finally, the antioxidant properties of the N2O2‐ligand and its cadmium coordination compounds were examined by DPPH and FRAP methods suggesting all the compounds have good antioxidant activity as compared with standard samples. [ABSTRACT FROM AUTHOR]

Proper surgical attire is essential in decreasing surgical site infections; however, the effectiveness of the different types of headwear is a controversial topic. We conducted a narrative review based on studies identified through a focused literature search to summarize and critically assess evidence and opinions on the most appropriate type of headwear for OR personnel. We included 48 articles: 17 original research studies and 31 non–peer‐reviewed articles of various types. Research published before 2014 mostly supports the complete coverage of all hair, which aligns with the 2015 AORN guidelines. However, more recent literature rebuts these guidelines and emphasizes the importance of clean headwear. Although earlier studies (published before 2017) lacked scientific rigor, later studies (published after 2017) have other various limitations, including missing data on compliance, surgery‐related techniques, and surgical attire other than headwear. The findings from this review highlight the importance of solid evidence‐based guidelines and expert collaboration. [ABSTRACT FROM AUTHOR]

Social media (SM) use has accelerated at an unprecedented pace and dermatology literature evaluating SM use is primarily centered on the quality and quantity of dermatologic content, with minimal research on how adolescent patients experience such content. We recruited 15 patients between the ages of 13–18 years from the Atrium Health Wake Forest Baptist Department of Dermatology to interview regarding their experience with dermatologic content on SM. Despite most participants' insightful comments on SM use and the relative lack of dermatologic content validation on SM, many participants adopted skin care advice from SM. Adolescents are particularly vulnerable to social influence and it is important dermatologists understand how pervasive skin‐related content is on these platforms. [ABSTRACT FROM AUTHOR]

Over the last decade especially, European authorities have successively invoked exceptional measures in the name of exceptional circumstances. This improvised mode of emergency response raises problems for EU legitimacy. After a brief analysis of the core patterns, the article examines the scope for reform. It considers the case for pre‐emptively strengthening the EU's emergency powers in the form of an 'emergency constitution'. It goes on to argue for more radical EU constitutional change, focused not on regulating the exceptional moment but simplifying and democratizing executive power, such that when hard times arrive it is better tied to a critical public. A concluding section discusses what can be achieved by retrospective contestation, as an interim solution in advance of constitutional change. [ABSTRACT FROM AUTHOR]

Using natural bond orbital theory, aromatic stabilization energies (NBO‐ASEs) were calculated for neutral and cationic monoheterocyclic three‐membered rings C2H2X(R)n (X = group 14–17 elements of rows 3–5; R = F, H or SiH3; and n = 0–2). Generally, there was a decrease in the (anti)aromatic nature of the molecule moving down the group as either the stabilizing orbital overlap (aromaticity) or destabilizing orbital interactions (antiaromaticity) were reduced due to larger atoms inducing longer bonds. (Anti)aromatic trends were supported with dissected nucleus independent chemical shift NICS(0)π,zz values (R2 = 0.94) and also by comparison of NBO‐ASEs to literature values for a selection of larger systems including benzene, cyclobutadiene, and the cyclopentadienyl anion. Comparisons are made to other studies that have used a range of approaches to study (anti)aromaticity in some of these molecules, and it was found that non‐dissected NICS values and homodesmotic equations often gave significantly overestimated if not misleading results. [ABSTRACT FROM AUTHOR]

The crystal structure of the pyridine‐substituted benzisoselenazolinone 2‐(pyridin‐3‐yl)‐2,3‐dihydro‐1,2‐benzoselenazol‐3‐one (C12H8N2OSe, 2), related to the antioxidant ebselen [systematic name: 2‐phenyl‐1,2‐benzoselenazol‐3(2H)‐one, 1], is characterized by strong intermolecular N...Se(—N) chalcogen bonding, where the N...Se distance of 2.3831 (6) Å is well within the sum of the van der Waals radii for N and Se (3.34 Å). This strong interaction results in significant lengthening of the internal N—Se distance, consistent with significant population of the Se—N σ* antibonding orbital. Much weaker intermolecular O...Se chalcogen bonding occurs between the amide‐like O atom in 2 and the less polarized C—Se bond in this structure. Charge density analysis of 2 using multipole refinement of high‐resolution data allowed the electrostatic surface potential for 2 to be mapped, and clearly reveals the σ‐hole at the extension of the Se—N bond as an area of positive electrostatic potential. Topological analysis of the electron‐density distribution in 2 was carried out within the Quantum Theory of Atoms in Molecules (QTAIM) framework and revealed bond paths and (3,−1) bond critical points (BCPs) for the N...Se—N moiety consistent with a closed‐shell interaction; however, the potential energy term is suggestive of electron sharing. Analysis of the electron localization function (ELF) for the strong N...Se and the weak O...Se chalcogen‐bonding interactions in the structure of 2 suggest significant electron sharing in the former interaction, and a largely electrostatic interaction in the latter. Conversion of 2 to its N‐methylated derivatives by reaction with methyl iodide [1‐methyl‐3‐(3‐oxo‐2,3‐dihydro‐1,2‐benzoselenazol‐2‐yl)pyridin‐1‐ium iodide, C13H11N2OSe+·I−] and methyl tosylate [1‐methyl‐3‐(3‐oxo‐2,3‐dihydro‐1,2‐benzoselenazol‐2‐yl)pyridin‐1‐ium toluenesulfonate trihydrate, C13H11N2OSe+·C7H7O3S−·3H2O] removes the possibility of N...Se chalcogen bonding and instead structures are obtained where the iodide and tosylate counter‐ions fulfill the role of chalcogen‐bond acceptors, with a strong I−...Se interaction in the iodide salt and a weaker p‐Tol‐SO3−...Se interaction in the tosylate salt. [ABSTRACT FROM AUTHOR]

Observation of the [M + H]+ ion in electrospray ionisation mass spectrometry (ESI‐MS) for either product identification or further unimolecular reactivity studies is not always guaranteed. When a suitable donor is β to a good leaving group such as protonated alcohols, neighbouring group participation (NGP) is one process that can lead to facile in‐source decomposition leading to three‐membered ring product ions. In this study, lone pair rich heteroatoms are explored computationally as donors for the intramolecular displacement of either water or ammonia in protonated 2‐heteroethanols and ethanamines, respectively. Density functional theory (DFT) calculations showed that for the halogens (Cl, Br and I) both the loss of water and ammonia are overall endothermic processes with modest barriers for the 2‐haloethanol fragmentation by NGP. The chalcogens (S, Se and Te) displayed a significant shift with the loss of water becoming exothermic and the enthalpic barrier approximately zero in most cases leading to little [M + H]+ ion observation. The loss of ammonia remained endothermic for both the chalcogens (S, Se and Te) and pnictogens (P, As and Sb), but the 2‐pnictoethanol fragmentation showed mixed results as two pathways were accessible due to the increased s character of the pnictogen lone pair. Examination of the donor–acceptor interactions by natural bond orbital (NBO) theory reflected an increase in the heteroatom lone pair participation at the transition state, but that stabilisation due to the polarisable CX bond dominated and should not be discounted in processes believed to proceed by nonvertical neighbouring group participation. [ABSTRACT FROM AUTHOR]

Intermetallic Pd‐doped (Fe,Ni)3P, which crystallizes in a non‐centrosymmetric tetragonal structure with S4 symmetry, has recently been discovered to host magnetic antiskyrmions, antivortex‐like topological spin textures. In this material, uniaxial magnetic anisotropy and dipolar interactions play a significant role, giving rise to finely branched magnetic domain patterns near the surface of bulk crystals, as revealed by a previous magnetic force microscopy (MFM) measurement. However, small‐angle neutron scattering (SANS) is a more suitable method for characterizing bulk properties and fractal structures on the mesoscopic length scale. In this study, using SANS and MFM, the magnetic domain structure in bulk single crystals of (Fe0.63Ni0.30Pd0.07)3P is quantitatively investigated. The SANS results demonstrate that the magnetic domain structure exhibits anisotropic fractal character on length scales down to the width of the magnetic domain walls. The fractal features are gradually lost in magnetic fields, and different field dependencies are observed at 300 and 2 K due to a temperature‐dependent anisotropy. This study quantifies the fractality of the highly anisotropic magnetic domain structures in an antiskyrmion material, and highlights the versatility of SANS for the study of fractal structures in magnetic systems. [ABSTRACT FROM AUTHOR]

In a β‐Mn‐type chiral magnet Co9Zn9Mn2, it is demonstrated that the magnetic field‐driven collapse of a room temperature metastable topological skyrmion crystal (SkX) passes through a regime described by a partial topological charge inversion. Using Lorentz transmission electron microscopy, the magnetization distribution is observed directly as the magnetic field is swept antiparallel to the original skyrmion core magnetization, that is, negative magnetic fields. Due to the topological stability of skyrmions, a direct transition of the metastable SkX to the equilibrium helical state is avoided for increasingly negative fields. Instead, the metastable SkX gradually transforms into giant magnetic bubbles separated by 2π domain walls. Eventually these large structures give way to form a near‐homogeneously magnetized medium that unexpectedly hosts a low density of isolated skyrmions with inverted core magnetization, and thus a total topological charge of reduced size and opposite sign compared with the initial state. A similar phenomenon has been observed previously in systems hosting ordered lattices of magnetic bubbles stabilized by the dipolar interaction and called "topological melting." With support from numerical calculations, it is argued here that the observed regime of partial topological charge inversion has its origin in the topological protection of the starting metastable skyrmion state. [ABSTRACT FROM AUTHOR]

Four cutaneous lesions were described as red or erythematous papules or nodules, resembling the most typical appearance of cutaneous metastases for renal cell carcinoma.[2] One lesion was described as an erythematous plaque with central dark scale. Metastatic disease is present in up to 33% of newly diagnosed renal cell carcinomas (RCC).[1] The most common sites of spread are lung, bone, abdomen, and brain, but skin metastases may be present in up to 8% of cases.[[1]] Cutaneous metastatic lesions may have varying appearances but typically present as solitary black, brown, or violaceous papules, nodules, or plaques that grow rapidly.[2] Since metastatic lesions may be the first presentation of underlying malignancy and prompt recognition of metastatic disease could expedite treatment, we sought to characterize the most frequent cutaneous and subcutaneous metastatic destinations of renal cell carcinoma.[3] Upon Wake Forest School of Medicine Institutional Review Board approval, we performed a retrospective chart review of patients with RCC metastatic to the skin. Five lesions were described as deeper palpable nodules with or without superficial discoloration, suggesting lesions to be primarily located in the subcutaneous tissue. [Extracted from the article]

Co–Zn–Mn chiral cubic magnets display versatile magnetic skyrmion phases, including equilibrium phases stable far above and far below room temperature, and the facile creation of robust far‐from‐equilibrium skyrmion states. In this system, compositional disorder and magnetic frustration are key ingredients that have profound effects on the chiral magnetism. Reported here are studies of the magnetism in Co6.75Zn6.75Mn6.5 by magnetometry, small‐angle neutron scattering (SANS), magnetic diffuse neutron scattering and Lorentz transmission electron microscopy (LTEM). While features in magnetometry and LTEM often give standard indications for skyrmion formation, they are not readily observed from the measurements on this system. Instead, skyrmion lattice correlations are only revealed by SANS, and they are found to form an orientationally disordered structure in a minority fraction of the sample. The majority fraction of the sample always displays orientationally disordered helical spin correlations, which undergo further disordering along the radial direction on cooling below the critical temperature (Tc ≃ 102 K). The near‐complete suppression of the skyrmion phase, and the process of disordering on cooling, are attributed to competing magnetic interactions that dominate over the ferromagnetic interaction expected to favour chiral magnetism in this system. These competing interactions start to develop above Tc and become further enhanced towards low temperatures. The present observations of co‐existing and disordered magnetic correlations over multiple length scales are not unique to Co6.75Zn6.75Mn6.5 but are seemingly common to the family of Co–Zn–Mn compounds with finite Mn, and their accurate description presents a challenge for theoretical modelling. In addition, this study highlights a need for neutron instrumentation capable of the comprehensive measurement of magnetic correlations over expanded ranges of momentum transfer in such multiple‐length‐scale magnets. [ABSTRACT FROM AUTHOR]

Co–Zn–Mn chiral cubic magnets display versatile magnetic skyrmion phases, including equilibrium phases stable far above and far below room temperature, and the facile creation of robust far‐from‐equilibrium skyrmion states. In this system, compositional disorder and magnetic frustration are key ingredients that have profound effects on the chiral magnetism. Reported here are studies of the magnetism in Co6.75Zn6.75Mn6.5 by magnetometry, small‐angle neutron scattering (SANS), magnetic diffuse neutron scattering and Lorentz transmission electron microscopy (LTEM). While features in magnetometry and LTEM often give standard indications for skyrmion formation, they are not readily observed from the measurements on this system. Instead, skyrmion lattice correlations are only revealed by SANS, and they are found to form an orientationally disordered structure in a minority fraction of the sample. The majority fraction of the sample always displays orientationally disordered helical spin correlations, which undergo further disordering along the radial direction on cooling below the critical temperature (Tc ≃ 102 K). The near‐complete suppression of the skyrmion phase, and the process of disordering on cooling, are attributed to competing magnetic interactions that dominate over the ferromagnetic interaction expected to favour chiral magnetism in this system. These competing interactions start to develop above Tc and become further enhanced towards low temperatures. The present observations of co‐existing and disordered magnetic correlations over multiple length scales are not unique to Co6.75Zn6.75Mn6.5 but are seemingly common to the family of Co–Zn–Mn compounds with finite Mn, and their accurate description presents a challenge for theoretical modelling. In addition, this study highlights a need for neutron instrumentation capable of the comprehensive measurement of magnetic correlations over expanded ranges of momentum transfer in such multiple‐length‐scale magnets. [ABSTRACT FROM AUTHOR]

Empirical data regarding dynamic alterations in illicit drug supply markets in response to the COVID‐19 pandemic, including the potential for introduction of novel drug substances and/or increased poly‐drug combination use at the "street" level, that is, directly proximal to the point of consumption, are currently lacking. Here, a high‐throughput strategy employing ambient ionization‐mass spectrometry is described for the trace residue identification, characterization, and longitudinal monitoring of illicit drug substances found within >6,600 discarded drug paraphernalia (DDP) samples collected during a pilot study of an early warning system for illicit drug use in Melbourne, Australia from August 2020 to February 2021, while significant COVID‐19 lockdown conditions were imposed. The utility of this approach is demonstrated for the de novo identification and structural characterization of β‐U10, a previously unreported naphthamide analog within the "U‐series" of synthetic opioid drugs, including differentiation from its α‐U10 isomer without need for sample preparation or chromatographic separation prior to analysis. Notably, β‐U10 was observed with 23 other drug substances, most commonly in temporally distinct clusters with heroin, etizolam, and diphenhydramine, and in a total of 182 different poly‐drug combinations. Longitudinal monitoring of the number and weekly "average signal intensity" (ASI) values of identified substances, developed here as a semi‐quantitative proxy indicator of changes in availability, relative purity and compositions of street level drug samples, revealed that increases in the number of identifications and ASI for β‐U10 and etizolam coincided with a 50% decrease in the number of positive detections and an order of magnitude decrease in the ASI for heroin. [ABSTRACT FROM AUTHOR]