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Conformational changes of the pyrophosphate (Pp)-functionalized uranyl peroxide nanocluster [(UO2)24(O2)24(P2O7)12]48- ({U24Pp12}), dissolved as a Li/Na salt, can be induced by the titration of alkali cations into solution. The most symmetric conformer of the molecule has idealized octahedral (Oh) molecular symmetry. One-dimensional 31P NMR experiments provide direct evidence that both K+ and Rb+ ions trigger an Oh-to-D4h conformational change within {U24Pp12}. Variable-temperature 31P NMR experiments conducted on partially titrated {U24Pp12} systems show an effect on the rates; increased activation enthalpy and entropy for the D4h-to-Oh transition is observed in the presence of Rb+ compared to K+. Two-dimensional, exchange spectroscopy 31P NMR revealed that magnetization transfer links chemically unique Pp bridges that are present in the D4h conformation and that this magnetization transfer occurs via a conformational rearrangement mechanism as the bridges interconvert between two symmetries. The interconversion is triggered by the departure and reentry of K (or Rb) cations out of and into the cavity of the cluster. This rearrangement allows Pp bridges to interconvert without the need to break bonds. Cs ions exhibit unique interactions with {U24Pp12} clusters and cause only minor changes in the solution 31P NMR signatures, suggesting that Oh symmetry is conserved. Single-crystal X-ray diffraction measurements reveal that the mixed Li/Na/Cs salt adopts D2h molecular symmetry, implying that while solvated, this cluster is in equilibrium with a more symmetric form. These results highlight the unusually flexible nature of the actinide-based {U24Pp12} and its sensitivity to countercations in solution.

Background: Catatonia is a complex syndrome with prominent psychomotor, cognitive, and affective manifestations. Among the commonly described manifestations of catatonia are mannerisms and stereotypies. Kahlbaum, who coined the term catatonia, described several presentations of mannerisms and stereotypies as complex behaviors in his monograph. However, most of the subsequent psychiatric literature has described both phenomena in the context of simple motor movements or actions. Study design or method: We identified complex behavioral presentations of mannerisms and stereotypies described by Kahlbaum in his monograph. We summarize the development and use of mannerisms and stereotypies as psychiatric terminology since Kahlbaum, emphasizing the spectrum of behavior captured early in this usage. We list the inconsistent and interchangeable use of these terms in subsequent literature and describe recent examples of complex behavioral manifestations of mannerisms and stereotypies in the context of catatonia. Study results: We propose a new framework for mannerisms and stereotypies that utilizes descriptive psychopathology factors in various normative references, the context of the behavior examined, and critical pathological processes identified in mannerisms and stereotypies to identify and describe complex manifestations of these phenomena. Conclusion: Catatonia continues to remain under-recognized and undertreated. Our current diagnostic tools can make mannerisms and stereotypies complex and challenging to recognize. We suggest defining stereotypies as noncontextual repetitive activities while mannerisms as non-contextual peculiarities of activities. Utilizing our proposed framework and definitions can improve the description, recognition, and treatment of catatonia. [ABSTRACT FROM AUTHOR]

Background: Catatonia has been increasingly associated with mood disorders and is recognized as a specifier in the DSM-5 and DSM-5-TR. The DSM-5-TR recognizes melancholia as a specifier for depressive episodes in major depressive disorder and bipolar disorder. It is characterized by severe anhedonia, lack of reactivity, excessive or delusional guilt, and significant vegetative symptoms. As the conceptualization of melancholia expanded beyond its mood components to include psychomotor disturbances, its overlap with psychomotor symptoms or catatonia becomes evident. This overlap was also described in Kahlbaum's original literature, where he describes the transition between states of melancholia, mania, and catatonia. Method: Case summary of six patients with major depressive disorder or depressed phase of bipolar disorder who were admitted for severe depression, anhedonia, intense anxiety, psychomotor agitation or retardation, indecisiveness, perseveration, and vegetative symptoms such as poor sleep, appetite, and significant weight loss. Results: All patients demonstrated rapid and complete resolution of their mood and psychomotor symptoms, indecisiveness, perseveration, as well as psychosis shortly after administration of lorazepam, with recurrence of the above symptoms upon lorazepam discontinuation and resolution upon resumption, in an on-and-off manner. Conclusion: The present study argues for a closer relationship between melancholia and catatonia based on our case series, historical review, overlap in phenomenology, and response to treatment. We propose provisional [Mahgoub] criteria for patients with severe depression and melancholia. The role of GABA agonists, such as lorazepam, can be explored as an option for patients with treatment-resistant depression who meet these criteria for melancholia. Limitations: Absence of a standardized, systematic assessment tool and a small sample size. [ABSTRACT FROM AUTHOR]