Predictive factors for decompensating events in patients with cirrhosis with primary biliary cholangitis under different lines of therapy.

BACKGROUND AND AIMS: The landscape in primary biliary cholangitis (PBC) has changed with the advent of second-line treatments. However, the use of obeticholic acid (OCA) and fibrates in PBC-related cirrhosis is challenging. We assessed the impact of receiving a second-line therapy as a risk factor for decompensated cirrhosis in a real-world population with cirrhosis and PBC, and identify the predictive factors for decompensated cirrhosis in these patients. APPROACH AND RESULTS: Multicenter study enrolling 388 patients with PBC-cirrhosis from the Spanish ColHai registry. Biopsy (20%), ultrasound (59%), or transient elastography (21%) defined cirrhosis, and the presence of varices and splenomegaly defined clinically significant portal hypertension (CSPH). Paris-II and PBC OCA international study of efficacy criteria determined the response to ursodeoxycholic acid (UDCA), fibrates (n=93), and OCA (n=104). The incidence of decompensated cirrhosis decreased for UDCA versus OCA or fibrates in the real-world population, but they were similar considering the propensity score-matched cohort (UDCA 3.77 vs. second-line therapy 4.5 100 persons-year, respectively), as patients on second-line therapy exhibited advanced liver disease. Consequently, GGT, albumin, platelets, clinically significant portal hypertension, and UDCA response were associated with a decompensating event. OCA response (achieved in 52% of patients) was associated with bilirubin (OR 0.21 [95% CI: 0.06-0.73]) and AST (OR 0.97 [95% CI: 0.95-0.99]), while fibrate response (achieved in 55% of patients) with AST [OR 0.96 (95% CI: 0.95-0.98]). In patients treated with OCA, drug response (sHR 0.23 [95% CI: 0.08-0.64]), diabetes (sHR 5.62 [95% CI: 2.02-15.68]), albumin (sHR 0.34 [95% CI: 0.13-0.89]), and platelets (sHR 0.99 [95% CI: 0.98-1.00]) were related to decompensation. In patients treated with fibrate, drug response (sHR 0.36 (95% CI: 0.14-0.95]), albumin (sHR 0.36 (95% CI: 0.16-0.81]), and clinically significant portal hypertension (sHR 3.70 (95% CI: 1.17-11.70]) were associated with decompensated cirrhosis. CONCLUSIONS: Advanced PBC, rather than OCA and fibrates, was found to be associated with decompensating events. Therefore, biochemical and clinical variables should be considered when making decisions about the management of these drugs. Moreover, a positive response to OCA and fibrates reduced the risk of decompensation.

Unusual Actinyl Complexes with a Redox-Active N,S-Donor Ligand.

Understanding the fundamental chemistry of soft N,S-donor ligands with actinides across the series is critical for separation science toward sustainable nuclear energy. This task is particularly challenging when the ligands are redox active. We herein report a series of actinyl complexes with a N,S-donor redox-active ligand that stabilizes different oxidation states across the actinide series. These complexes are isolated and characterized in the gas phase, along with high-level electronic structure studies. The redox-active N,S-donor ligand in the products, C5H4NS, acts as a monoanion in [UVIO2(C5H4NS-)]+ but as a neutral radical with unpaired electrons localized on the sulfur atom in [NpVO2(C5H4NS•)]+ and [PuVO2(C5H4NS•)]+, resulting in different oxidation states for uranium and transuranic elements. This is rationalized by considering the relative energy levels of actinyl(VI) 5f orbitals and S 3p lone pair orbitals of the C5H4NS- ligand and the cooperativity between An-N and An-S bonds that provides additional stability for the transuranic elements.

Central retinal artery occlusion with cilioretinal artery sparing secondary to COVID-19: Additional ocular complication.

We describe a 68-year-old female patient with unilateral central retinal artery occlusion (CRAO) with cilioretinal artery sparing post-coronavirus disease 2019 (COVID-19) infection. The patient presented with acute vision loss in the left eye 11 days after discharge from a severe COVID-19 infection, with altered D-dimer, C-reactive protein, and fibrinogen levels. The best-corrected visual acuity (BCVA) in the left eye was 20/400; fundoscopic examination revealed diffuse pallor retina with a patent arterial branch from the optic disk to the fovea, confirmed by fluorescein angiography. CRAO with a cilioretinal artery sparing post-COVID-19 may be considered an additional ocular manifestation of the post-acute COVID-19 syndrome spectrum.

Prevalence estimation of significant fibrosis because of NASH in Spain combining transient elastography and histology.

BACKGROUND & AIMS: Non-alcoholic fatty liver disease (NAFLD) has become a major public health problem, but the prevalence of fibrosis associated with non-alcoholic steatohepatitis (NASH) is largely unknown in the general population. This study aimed to provide an updated estimation of the prevalence of NASH fibrosis in Spain. METHODS: This was an observational, retrospective, cross-sectional, population-based study with merged data from two Spanish datasets: a large (N = 12 246) population-based cohort (ETHON), including transient elastography (TE) data, and a contemporary multi-centric biopsy-proven NASH cohort with paired TE data from tertiary centres (N = 501). Prevalence for each NASH fibrosis stage was estimated by crossing TE data from ETHON dataset with histology data from the biopsy-proven cohort. RESULTS: From the patients with valid TE in ETHON dataset (N = 11 440), 5.61% (95% confidence interval [95% CI]: 2.53-11.97) had a liver stiffness measurement (LSM) ≥ 8 kPa. The proportion attributable to NAFLD (using clinical variables and Controlled Attenuation Parameter) was 57.3% and thus, the estimated prevalence of population with LSM ≥ 8 kPa because of NAFLD was 3.21% (95% CI 1.13-8.75). In the biopsy-proven NASH cohort, 389 patients had LSM ≥ 8 kPa. Among these, 37% did not have significant fibrosis (F2-4). The estimated prevalence of NASH F2-3 and cirrhosis in Spain's adult population were 1.33% (95% CI 0.29-5.98) and 0.70% (95% CI 0.10-4.95) respectively. CONCLUSIONS: These estimations provide an accurate picture of the current prevalence of NASH-related fibrosis in Spain and can serve as reference point for dimensioning the therapeutic efforts that will be required as NASH therapies become available.

Non-invasive tests accurately stratify patients with NAFLD based on their risk of liver-related events.

BACKGROUND & AIMS: Previous studies on the prognostic significance of non-invasive liver fibrosis tests in non-alcoholic fatty liver disease (NAFLD) lack direct comparison to liver biopsy. We aimed to evaluate the prognostic accuracy of fibrosis-4 (FIB4) and vibration-controlled transient elastography (VCTE), compared to liver biopsy, for the prediction of liver-related events (LREs) in NAFLD. METHODS: A total of 1,057 patients with NAFLD and baseline FIB4 and VCTE were included in a multicenter cohort. Of these patients, 594 also had a baseline liver biopsy. The main study outcome during follow-up was occurrence of LREs, a composite endpoint combining cirrhosis complications and/or hepatocellular carcinoma. Discriminative ability was evaluated using Harrell's C-index. RESULTS: FIB4 and VCTE showed good accuracy for the prediction of LREs, with Harrell's C-indexes >0.80 (0.817 [0.768-0.866] vs. 0.878 [0.835-0.921], respectively, p = 0.059). In the biopsy subgroup, Harrell's C-indexes of histological fibrosis staging and VCTE were not significantly different (0.932 [0.910-0.955] vs. 0.881 [0.832-0.931], respectively, p = 0.164), while both significantly outperformed FIB4 for the prediction of LREs. FIB4 and VCTE were independent predictors of LREs in the whole study cohort. The stepwise FIB4-VCTE algorithm accurately stratified the risk of LREs: compared to patients with "FIB4 <1.30", those with "FIB4 ≥1.30 then VCTE <8.0 kPa" had similar risk of LREs (adjusted hazard ratio [aHR] 1.3; 95% CI 0.3-6.8), whereas the risk of LREs significantly increased in patients with "FIB4 ≥1.30 then VCTE 8.0-12.0 kPa" (aHR 3.8; 95% CI 1.3-10.9), and even more for those with "FIB4 ≥1.30 then VCTE >12.0 kPa" (aHR 12.4; 95% CI 5.1-30.2). CONCLUSION: VCTE and FIB4 accurately stratify patients with NAFLD based on their risk of LREs. These non-invasive tests are alternatives to liver biopsy for the identification of patients in need of specialized management. LAY SUMMARY: The amount of fibrosis in the liver is closely associated with the risk of liver-related complications in non-alcoholic fatty liver disease (NAFLD). Liver biopsy currently remains the reference standard for the evaluation of fibrosis, but its application is limited by its invasiveness. Therefore, we evaluated the ability of non-invasive liver fibrosis tests to predict liver-related complications in NAFLD. Our results show that the blood test FIB4 and transient elastography stratify the risk of liver-related complications in NAFLD, and that transient elastography has similar prognostic accuracy as liver biopsy. These results support the use of non-invasive liver fibrosis tests instead of liver biopsy for the management of patients with NAFLD.

Comparação entre a apendicectomia laparoscópica versus aberta: revisão dos principais ensaios clínicos / Comparison between laparoscopic versus open appendectomy: review of major clinical trials

Introdução: A apendicite é uma das emergências cirúrgicas mais comuns na prática clínica. Existem duas modalidades operatórias que são utilizadas atualmente para o manejo da apendicite, sendo elas a cirurgia aberta e a laparoscópica. Perante as controvérsias relacionadas às vantagens e desvantagens tanto da apendicectomia aberta quanto da laparoscópica, pretende-se, com esta revisão, e baseando-se nos resultados dos principais ensaios clínicos relacionados ao tema, fornecer um material resumido e em lingua portuguesa, e que permita ao cirurgião decidir sobre o melhor método cirúrgico com base nas características individuais de cada paciente. Objetivo: Realizar uma revisão da literatura dos ensaios clínicos que buscaram comparar os resultados da apendicectomia laparoscópica versus aberta. Método: Trata-se de um estudo exploratório baseado no método de revisão da literatura com síntese de evidências. A base de dados escolhida para seleção dos trabalhos foi a PUBMED, utilizando a seguinte estratégia de busca: appendicectomy[title] AND (laparoscopic[title] AND open[title]). Como critério de inclusão, estabeleceu-se que apenas ensaios clínicos seriam incluídos na amostra. Nenhum corte temporal foi estabelecido.. Resultados: A busca pelos artigos foi realizada no mês de setembro de 2021. De início, foram identificados 15 artigos. Após a leitura dos títulos e resumos, 14 artigos foram mantidos na amostra, sendo em seguida revisados. Conclusões: Foi proposto que, apesar de maior tempo operatório, além de maior custo, a LA teria vantagens sobre a OA para a maioria das suspeitas de apendicite, especialmente aguda. As vantagens frequentemente apontadas foram a redução do número de infecções de feridas, retorno mais precoce dos pacientes às atividades normais, recuperação mais rápida, cosmese melhorada, menor dor pós-operatória e uma tendência de melhor atividade física pós-operatória. Palavras-chave: Cirurgia. Apendicectomia. Cirurgia Aberta. Cirurgia Laparoscópica.

Analysis of Common Pathways and Markers From Non-Alcoholic Fatty Liver Disease to Immune-Mediated Diseases.

Metabolic associated fatty liver disease (MAFLD) is the most prevalent form of liver disease worldwide, accounting for a high liver-related mortality and morbidity with extensive multi-organ involvement. This entity has displaced viral hepatitis as the main cause of severe forms of hepatic diseases, although the onset and transition of MAFLD stages still remains unclear. Nevertheless, innate and adaptive immune responses seem to play an essential role in the establishment and further progression of this disease. The immune system is responsible of safeguard and preserves organs and systems function, and might be altered under different stimuli. Thus, the liver suffers from metabolic and immune changes leading to different injuries and loss of function. It has been stablished that cell-cell crosstalk is a key process in the hepatic homeostasis maintenance. There is mounting evidence suggesting that MAFLD pathogenesis is determined by a complex interaction of environmental, genetic and host factors that leads to a full plethora of outcomes. Therefore, herein we will revisit and discuss the interplay between immune mechanisms and MAFLD, highlighting the potential role of immunological markers in an attempt to clarify its relationship.

Oculomotor nerve palsy in an asymptomatic child with COVID-19.

We report the case of a 2-year-old girl with acute-onset divergent strabismus and ptosis in the right eye. She had an exotropia of 45Δ for near, eyelid ptosis affecting the visual axis, adduction, limitations of up- and downgaze, and a discrete mydriasis in the right eye. Neurological conditions were ruled out. Serology was positive for SARS-CoV-2 antibodies. The patient was managed conservatively with ocular physiotherapy and close visual acuity monitoring. On follow-up examination at 1 month, there was marked improvement of the exotropia (25Δ for near), adduction, ptosis, and mydriasis.

Mobile emergency services: the actions of the nursing team in situations of violence / Serviço de atendimento móvel de urgência: atuação da equipe de enfermagem em ocorrências violentas

This study aimed to evaluate the profile of attention of the mobile emergency services in cases of violence and the actions of the nursing team. Observational, exploratory and analytical study were undertaken from secondary records. A Correspondence Analysis was conducted to identify the associations between the actions of the nursing team and the profile of the necessity of care due to violent causes. The results showed that from 1800 cases, most took place during the weekend (49.2%), involving men (70.0%) and traffic accidents (76.5%). The correspondence analysis highlighted two dimensions (76.7% of explanatory contribution), resulting in three similar groups considering the nursing professional taking part in the attention, how the situation ended, period in which it occurred, and profile of the victim. The performed analysis was strategic for the systematization of data which gave support to the situational understanding of the composition of the service and for the planning of the actions of the nursing team.

Objetivo: analisar o perfil de atendimento do serviço móvel de urgência em ocorrências de causas violentas e a atuação da equipe de enfermagem. Métodos: estudo observacional, exploratório e analítico de registros secundários. Empreendeu-se Análise de Correspondência para identificar associações entre a atuação da equipe de enfermagem e o perfil da demanda por causas violentas assistidas. Resultados: total de 1800 ocorrências, entre as quais prevaleceram atendimentos no final de semana (49,2%), aos homens (70,0%), envolvendo acidentes de transito (76,5%). A análise de correspondência privilegiou duas dimensões (76,7% de contribuição explicativa), resultando em três grupos similares conforme trabalhador de enfermagem atuante no atendimento, desfecho da ocorrência, período e perfil da vítima. Conclusão: a análise se apresentou estratégica para sistematização de dados apoiadores à compreensão situacional do desempenho do serviço e planejamento do trabalho da equipe de enfermagem.

Treatment of refractory amblyopia with levodopa associated with full-time occlusion in the dominant eye / Tratamento da ambliopia refratária com o uso de levodopa associada à oclusão total do olho dominante

Abstract Purpose: To evaluate visual outcomes of levodopa treatment associated with full occlusion of the dominant eye in patients with refractory amblyopia. Methods: A prospective study of 19 attended patients who were subject to treatment with Levodopa and Carbidopa on doses of 0.7mg/kg/day, a ratio of 4:1 divided into three daily doses for 5 weeks, combined with full occlusion (24 hours/day) of the dominant eye. The ophthalmologic exam from previous consultations up to treatment and after 8 weeks of therapy were collected from medical record data. Patients who had completed treatment for more than 12 months were included for complete eye examination. Results: The mean age before treatment with levodopa was 11.0 ± 4.2 years old (varying from 7 to 23 years). The best-corrected visual acuity (Snellen chart) of the amblyopic eye before treatment was 0.24 (0.6 in logMAR) ± 0.16, after 8 weeks of treatment it was 0.47(0.3 in logMAR) ± 0.33, while during the final evaluation it was 0.46 (0.3 in logMAR) ± 0.34. There was a statistically significant improvement in vision after 8 weeks of therapy which was maintained until the final evaluation (p = 0.007). Conclusion: Levodopa/Carbidopa therapyat doses of 0.7 mg/kg/day at a ratio of 4:1 divided in three daily doses, associated with full occlusion of the dominant eye during 5 weeks had a significant improvement on the visual acuity of the amblyopic eye, and persisted up to 1 year after the treatment.

Resumo Objetivo: Avaliar os resultados visuais do tratamento com levodopa associada à oclusão total do olho dominante em pacientes amblíopes. Métodos: Estudo prospectivo de 19 pacientes atendidos e submetidos ao tratamento com levodopa e carbidopa na dose de 0,7 mg/kg/dia e proporção de 4:1, divididos em três doses diárias, durante cinco semanas, combinada a oclusão total (24 horas/dia) do olho dominante. Foram coletados dados do prontuário referentes ao exame oftalmológico da consulta anterior ao tratamento e após 8 semanas de terapia. Os pacientes com término do tratamento com mais de 12 meses foram reconvocados para exame oftalmológico completo. Resultados: A média de idade dos pacientes previamente ao tratamento com levodopa foi de 11,0 ± 4,2 anos (variando de 7 a 23 anos). A acuidade visual melhor corrigida (Snellen) do olho amblíope antes do tratamento foi de 0,24 (0,6 em logMAR) ± 0,16, após 8 semanas de tratamento foi de 0,47 (0,3 em logMAR) ± 0,33 e na avaliação final foi de 0,46 (0,3 em logMAR) ± 0,34. Houve melhora estatisticamente significante da visão após 8 semanas de tratamento que se manteve até a avaliação final (p = 0,007) Conclusão: A terapia com levodopa/carbidopa em doses de 0,7mg/kg/dia na proporção de 4:1 dividida em três doses diárias, associada à oclusão total do olho dominante durante 5 semanas, apresentou uma melhora significativa na acuidade visual do olho ambliópico e persistiu até 1 ano após o tratamento.

Chemical evidence of the stability of praseodymium(v) in gas-phase oxide nitrate complexes.

The diverse reactivity of [LnO2(NO3)2]- complexes with water in the gas phase, for Ln = Ce, Pr and Nd, examined in a quadrupole ion trap and complemented by ab initio computations, illuminates the chemical stability of Pr in the unusual +5 oxidation state.

A fast and selective method for the determination of 8 carcinogenic polycyclic aromatic hydrocarbons in rubber and plastic materials.

Polycyclic Aromatic Hydrocarbons (PAHs) have been detected in rubber and plastic components of a number of consumer products such as toys, tools for domestic use, sports equipment, and footwear, with carbon black and extender oils having been identified as principal sources. In response to these findings, the European Union Regulation (EU) No. 1272/2013 was adopted in December 2013, amending entry 50 in Annex XVII to the Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) directive establishing a restriction on the content of eight individual carcinogenic PAHs in plastic and rubber parts of products supplied to the public. This work proposes a simple, relatively fast, and cost effective method for determining the concentrations of each of these eight carcinogenic PAHs for compliance testing. Existing methodologies were taken as a starting point, improving in particular the extraction and the clean-up procedures. Randall hot extraction and ultrasonic extraction were compared with regard to their extraction efficiency. Randall hot extraction proved to be more efficient (10-40%, depending on PAH). Sample extract clean-up performance was qualitatively assessed for silica-packed columns and molecularly imprinted polymers (MIPs) solid phase extraction (SPE) cartridges. The use of highly selective MIP-SPE cartridges removed most of the undesired contaminants, highlighting their superiority with regard to traditional, silica-based purification methodologies. The introduction of Randall-hot extraction for sample extraction and MIP-based solid phase extraction cartridges for selective clean-up represents a novel advance compared with previously reported methods in this field. In combination with gas chromatography-mass spectrometry (GC-MS) analyses in selected ion mode, the method was found to be excellent in terms of extraction efficiency, extract purity, and speed.

Synthesis, structure and bonding of actinide disulphide dications in the gas phase.

Actinide disulphide dications, AnS22+, were produced in the gas phase for An = Th and Np by reaction of An2+ cations with the sulfur-atom donor COS, in a sequential abstraction process of two sulfur atoms, as examined by FTICR mass spectrometry. For An = Pu and Am, An2+ ions were unreactive with COS and did not yield any sulphide species. High level multiconfigurational (CASPT2) calculations were performed to assess the structures and bonding of the new AnS22+ species obtained for An = Th, Np, as well as for An = Pu to examine trends along the An series, and for An = U to compare with a previous experimental study and DFT computational scrutiny of US22+. The CASPT2 results showed that, like in the case of uranium, the new AnS22+ ions have ground states with triangular geometries, corresponding to the presence of a persulphide in the case of thorium that formally leads to a stable ThIVS22+ species, while a supersulphide appears to be present in the case of U, Np and Pu, formally leading to a AnIIIS22+ species. The computations also revealed that linear thioactinyl structures are higher in energy, with a difference that increases fourfold upon moving from U to Pu, apparently indicating that it will be even more pronounced for Am.

Avaliação das urgências oftalmológicas em um hospital público de referência em Pernambuco / Evaluation of ophthalmic emergencies in a public reference hospital in Pernambuco

RESUMO Objetivo: Avaliar as urgências oftalmológicas em um hospital público de referência de Pernambuco. Métodos: Estudo transversal e retrospectivo, com 26.358 pacientes atendidos na emergência oftalmológica da Fundação Altino Ventura , no período janeiro a junho de 2013. Os dados foram coletados por meio de protocolos baseados nas fichas de cadastro eletrônicas da emergência oftalmológica. Resultados: Observou-se que 52,5% dos indivíduos eram do gênero masculino e 42,5% encontravam-se na faixa etária de 21 a 40 anos; 90,8% eram provenientes da região Metropolitana do Recife e 55% dos casos foram classificados como de baixa gravidade. Os diagnósticos mais frequentes foram conjuntivite (35,17%) e trauma ocular (19,25%). Conclusão: Houve prevalência de pacientes do gênero masculino, na faixa etária de 21 a 40 anos, proveniente da região Metropolitana do Recife, classificado como baixa gravidade, atendidos no mês de janeiro, na segunda-feira, com o diagnóstico de conjuntivite, seguida por trauma ocular.

ABSTRACT Purpose: To evaluate ophthalmological emergencies in a public reference hospital in Pernambuco. Methods: Cross-sectional retrospective study with 26.358 patients attended in the ophthalmic emergency Altino Ventura Foundation, in the period january to june 2013. Data were collected using protocols based on electronic registration forms of ophthalmological emergency Results: It was observed that 52.5% of patients were male, 42.5% were aged 21-40 years; 90.8% were from the region metropolitan area of Recife; 55% classified as less severe. The main diagnoses were conjunctivitis (35.17%) and ocular trauma (19.25%). Conclusion: The prevalence of male patients, aged 21-40 years, from the metropolitan area of Recife, classified as low complexity, attended in January, on Monday, with the diagnosis of conjunctivitis, followed by ocular trauma.

Abdome agudo inflamatório em pediatria / Inflammatory acute abdome in pediatrics

A etiologia mais comumente relacionada ao quadro de abdome agudo inflamatório na criança é a apendicite aguda. O diagnóstico é essencialmente clínico, mas quando houver dúvida diagnóstica, podem ser empregados métodos de imagem. A conduta varia de acordo com o estágio da doença.

The etiology most commonly related to inflammatory acute abdomen in children is acute appendicitis. The diagnosis is primarily clinical, but imaging methods can be used when there is diagnostic uncertainty. Management varies according to the stage of the disease.

Abordagem ao trauma abdominal fechado / Approach to closed abdominal trauma

O trauma abdominal fechado, responsável por boa parte das lesões abdominais decorrentes de trauma, pode se manifestar clinicamente de muitas formas. A conduta depende do status clínico do paciente. O objetivo dessa revisão é analisar o trauma abdominal fechado e sua repercussão na vítima.

The blunt abdominal trauma, responsible for most abdominal injuries resulting from trauma, can manifest clinically in many ways. The management depends on the clinical status of the patient. The focus of this review is to analyze the blunt abdominal trauma and its impact on the victim

Asma brônquica: conduta na emergência pediátrica / Bronchial asthma ­ management in the pediatric emergency

A asma é uma das doenças crônicas mais comuns na infância e seu correto manejo no serviço de emergência é de suma importância. Face a uma crise de asma, a conduta irá depender dos sinais de alarme e da idade do paciente, sendo ela dividida em crianças maiores e menores de 5 anos.

Asthma is one of the most common chronic diseases in children. In the emergency room, the correct management can save a patient's life. When facing an asthma flare-up, the treatment will depend on the warning signs and the patient's age group, either older or younger than 5 years old.

Gas-phase reactions of molecular oxygen with uranyl(V) anionic complexes-synthesis and characterization of new superoxides of uranyl(VI).

Gas-phase complexes of uranyl(V) ligated to anions X(-) (X = F, Cl, Br, I, OH, NO3, ClO4, HCO2, CH3CO2, CF3CO2, CH3COS, NCS, N3), [UO2X2](-), were produced by electrospray ionization and reacted with O2 in a quadrupole ion trap mass spectrometer to form uranyl(VI) anionic complexes, [UO2X2(O2)](-), comprising a superoxo ligand. The comparative rates for the oxidation reactions were measured, ranging from relatively fast [UO2(OH)2](-) to slow [UO2I2](-). The reaction rates of [UO2X2](-) ions containing polyatomic ligands were significantly faster than those containing the monatomic halogens, which can be attributed to the greater number of vibrational degrees of freedom in the polyatomic ligands to dissipate the energy of the initial O2-association complexes. The effect of the basicity of the X(-) ligands was also apparent in the relative rates for O2 addition, with a general correlation between increasing ligand basicity and O2-addition efficiency for polyatomic ligands. Collision-induced dissociation of the superoxo complexes showed in all cases loss of O2 to form the [UO2X2](-) anions, indicating weaker binding of the O2(-) ligand compared to the X(-) ligands. Density functional theory computations of the structures and energetics of selected species are in accord with the experimental observations.

Synthesis and hydrolysis of gas-phase lanthanide and actinide oxide nitrate complexes: a correspondence to trivalent metal ion redox potentials and ionization energies.

Several lanthanide and actinide tetranitrate ions, M(III)(NO3)4(-), were produced by electrospray ionization and subjected to collision induced dissociation in quadrupole ion trap mass spectrometers. The nature of the MO(NO3)3(-) products that result from NO2 elimination was evaluated by measuring the relative hydrolysis rates under thermalized conditions. Based on the experimental results it is inferred that the hydrolysis rates relate to the intrinsic stability of the M(IV) oxidation states, which correlate with both the solution IV/III reduction potentials and the fourth ionization energies. Density functional theory computations of the energetics of hydrolysis and atoms-in-molecules bonding analysis of representative oxide and hydroxide nitrates substantiate the interpretations. The results allow differentiation between those MO(NO3)3(-) that comprise an O(2-) ligand with oxidation to M(IV) and those that comprise a radical O(-) ligand with retention of the M(III) oxidation state. In the particular cases of MO(NO3)3(-) for M = Pr, Nd and Tb it is proposed that the oxidation states are intermediate between M(III) and M(IV).