Quantum chemical calculations have been performed to study the nature of interaction of complexes formed by MgX2(X = H, F) molecules with acetylene, ethylene, and benzene.

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A new series of superalkali-based alkalides, i.e., Li3(+)(calix[4]pyrrole)M(-), Li3O(+)(calix[4]pyrrole)M(-), and M3O(+)(calix[4]pyrrole)K(-) (M = Li, Na, and K), have been theoretically designed and investigated by means of density functional theory computations. These species have diverse structural isomers, in which the embedded superalkali units maintain their identities and prefer the horizontal orientation over the vertical one. All the proposed alkalides exhibit considerable first hyperpolarizabilities (β0) up to 34,718 au. Especially, a prominent M(-) atomic number dependence of (hyper)polarizabilities is observed for the Li3(+)(calix[4]pyrrole)M(-) and Li3O(+)(calix[4]pyrrole)M(-) compounds. Besides, the dependence of the nonlinear optical response of such alkalides on the species of involved superalkalis is also investigated. We hope that this work will promote further application of superalkalis and, on the other hand, attract more research interest and efforts in exploring new, unconventional alkalides.

Changes in global climate have raised concerns about the emergence and resurgence of infectious diseases.Vibrio cholerae is a reemerging pathogen that proliferates and is transported on marine particles. Patterns of cholera outbreaks correlate with sea surface temperature increases, but the underlying mechanisms for rapid proliferation of V. cholerae during ocean warming events have yet to be fully elucidated. In this study, we tested the hypothesis that autochthonous marine bacteria impede the spread of V. cholerae in the marine environment. It was found that some marine bacteria are capable of inhibiting the growth of V. cholerae on surfaces and that bacterial isolates derived from pelagic particles show a greater frequency of V. cholerae inhibition than free-living bacteria. Vibrio cholerae was less susceptible to antagonism at higher temperatures, such as those measured during El Niño-Southern Oscilliation and monsoonal events. Using a model system employing green fluorescent protein-labeled bacteria, we found that marine bacteria can directly inhibit V. cholerae colonization of particles. The mechanism of inhibition in our model system was linked to the biosynthesis of andrimid, an antibacterial agent. Antibiotic production by the model antagonistic strain decreased at higher temperatures, thereby explaining the increased competitiveness of V. cholerae under warmer conditions. These findings suggest that bacterium-bacterium antagonism is a contributing mechanism in regulating the proliferation of V. cholerae on marine particles.

The creative concept of superatom brings a new dimension to the conventional periodic table, which has been gradually enriched by both theoretical and experimental research. In this article, we propose a new member, namely, Al12Be, to the superatom family. The amazing similarity between the Al12Be cluster and the chalcogen elements makes the former an excellent superatom counterpart of the latter. In addition, Al12Be exhibits more exothermic first electron affinity (EA) and less endothermic second EA values due to its size advantage over the chalcogen atoms, showing the superatom superiority in this respect. The stable compounds formed between Al12Be and other atoms, such as carbon, beryllium, calcium, and lithium, provide further evidence to support the quasi-chalcogen identity of Al12Be.

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This largest VHL survival analysis indicates that onset age, family history, mutation type and first presenting symptom have an effect on the survival of patients with VHL disease, which is helpful to genetic counselling and clinical decision-making.

On the basis of stable alkaline earth metal ammines, a series of M(NH3)6NaCl and M(NH3)6Na2 (M = Mg and Ca) excess electron compounds were theoretically constructed and studied by using the density functional theory. The electride or alkalide characteristics of these compounds are verified by their electronic structures, HOMOs, and small VIE values. It is worth noting that the M(NH3)6Na2 alkalides have novel electronic structures that contain double alkali metal anions. As expected, all the noncentrosymmetric M(NH3)6NaCl and M(NH3)6Na2 compounds possess considerable first hyperpolarizabilities (β0) up to 123 050 au, which can be attributed to low excitation energies (ΔEs) and large oscillator strength (f0) of their crucial excited states. In addition, results reveal that the Ca(NH3)6-based species with lower ΔEs and larger transition moments (Δμ) show larger β0 values compared with the corresponding Mg(NH3)6-based ones with similar geometries. This study may be significant in terms of designing excess electron compounds of new-type, especially alkalides with multiple alkali metal anions.