Disentangling the evolution of electrons and holes in photoexcited ZnO nanoparticles.

The evolution of charge carriers in photoexcited room temperature ZnO nanoparticles in solution is investigated using ultrafast ultraviolet photoluminescence spectroscopy, ultrafast Zn K-edge absorption spectroscopy, and ab initio molecular dynamics (MD) simulations. The photoluminescence is excited at 4.66 eV, well above the band edge, and shows that electron cooling in the conduction band and exciton formation occur in <500 fs, in excellent agreement with theoretical predictions. The x-ray absorption measurements, obtained upon excitation close to the band edge at 3.49 eV, are sensitive to the migration and trapping of holes. They reveal that the 2 ps transient largely reproduces the previously reported transient obtained at 100 ps time delay in synchrotron studies. In addition, the x-ray absorption signal is found to rise in ∼1.4 ps, which we attribute to the diffusion of holes through the lattice prior to their trapping at singly charged oxygen vacancies. Indeed, the MD simulations show that impulsive trapping of holes induces an ultrafast expansion of the cage of Zn atoms in <200 fs, followed by an oscillatory response at a frequency of ∼100 cm-1, which corresponds to a phonon mode of the system involving the Zn sub-lattice.

X-ray induced electron and ion fragmentation dynamics in IBr.

Characterization of the inner-shell decay processes in molecules containing heavy elements is key to understanding x-ray damage of molecules and materials and for medical applications with Auger-electron-emitting radionuclides. The 1s hole states of heavy atoms can be produced by absorption of tunable x rays and the resulting vacancy decays characterized by recording emitted photons, electrons, and ions. The 1s hole states in heavy elements have large x-ray fluorescence yields that transfer the hole to intermediate electron shells that then decay by sequential Auger-electron transitions that increase the ion's charge state until the final state is reached. In molecules, the charge is spread across the atomic sites, resulting in dissociation to energetic atomic ions. We have used x-ray/ion coincidence spectroscopy to measure charge states and energies of Iq+ and Brq'+ atomic ions following 1s ionization at the I and Br K-edges of IBr. We present the charge states and kinetic energies of the two correlated fragment ions associated with core-excited states produced during the various steps of the cascades. To understand the dynamics leading to the ion data, we develop a computational model that combines Monte-Carlo/Molecular-Dynamics (MC/MD) simulations with a classical over-the-barrier model to track inner-shell cascades and redistribution of electrons in valence orbitals and nuclear motion of fragments.

Developing a Pediatric EHR Testing & Certification Program in the USA: Initial Phase.

In 2016, the 21st Century Cures Act included ONC's 10 functionality recommendations for voluntary testing and certification of pediatric EHRs. Since 2019, Drummond has been developing a new pediatric EHR testing and certification program with pediatric and industry experts. The testing criteria are based upon AAP's 47 requirements that include ONC's 10 recommendations. It is anticipated the program will be operationalized and ready for EHR vendors in 1Q2022.

Estudio descriptivo sobre el perfil de los pacientes derivados a la Unidad de Tratamiento del Dolor Crónico del Hospital Universitario de Gran Canaria Dr. Negrín (utdc-hugcdn) como base para la reorganización de esta / Descriptive study on the profile of patients sent to the Chronic Pain Treatment Unit of the University Hospital of Gran Canaria Dr. Negrín (utdc-hugcdn) as a basis for the reorganization of this

Objetivo: Conocer las necesidades y fortalezas de nuestra Unidad derivadas del conocimiento del perfil de paciente que es remitido para la atención en la misma. Pacientes y métodos: Estudio descriptivo transversal sobre 5000 pacientes derivados a nuestra Unidad entre 2017 y 2020. Se recogieron de forma anónima los siguientes datos: número de pacientes remitidos por mes, edad, sexo, servicio remisor, localización del dolor, pacientes/interconsultas preferentes, rechazados y atendidos previamente. De los 1000 primeros pacientes también se registraron los antecedentes quirúrgicos, existencia o no de obesidad y consumo de fármacos psicoactivos. Resultados: Son derivados para valoración unos 1560 pacientes de media anuales (130 al mes), con una edad media de 59,8 años (± 14,3) de los cuales el 62,6 % son mujeres. Un 62,08 % se encontraba en edad laboral. Los servicios asistenciales que remitieron más pacientes fueron: Traumatología, Neurocirugía, Unidad de Raquis y Rehabilitación. El 6,6 % de las derivaciones fueron calificadas como preferentes. Fueron rechazadas el 9,98 % de las interconsultas. Los tipos de dolores según su localización más frecuentes fueron: lumbalgia, cervicalgia y dolores generalizados. Se constató la toma habitual de ansiolíticos y/o antidepresivos en un 34,9 %, el 10,8 % eran obesos y el 10,3 % sufrían dolor crónico postquirúrgico. Conclusiones: El perfil del paciente predominante derivado a nuestra unidad suele ser el de un adulto mayor, en edad laboral, de género femenino, derivado desde el servicio de Traumatología y con dolor en la región lumbar, perfil muy similar al descrito en otras unidades del dolor del mundo occidental desarrollado. Más de 1 de cada 3 pacientes puede sufrir ansiedad y/o depresión, siendo también muy frecuente el dolor postquirúrgico y la obesidad.(AU)

Objective: Determine the shortcomings and strengths of our pain clinic derived from the knowledge of the profile of the patients who are referred for care in the clinic. Patients and methods: Cross-sectional descriptive study on 5000 patients referred to our pain clinic between 2017 y 2020. The following data were collected: number of patients referred per month, age, sex, referring service, location of pain, patients referred preferentially, rejected patients, and previously attended consultations. Data on surgical history, obesity, and use of psychoactive drugs were also recorded for the first 1000 patients. Results: An average of 1560 patients were referred for evaluation per year (130 per month), with a mean age of 59.8 years (± 14.3) of which 62.6 % are women and 62.08 % were of working age. The healthcare services that referred the most patients were Orthopedic Surgery, Neurosurgery, Spine Unit and Rehabilitation. 6.6 % of the requests were derived preferentially. Of the referrals, 9.98 % were rejected. The most frequent pain locations were low back pain, neck pain and generalized pain. In the The usual taking of anxiolytics and / or antidepressants was found in 34.9 %, 10.8 % were diagnosed as obese and 10.3 % were referred for chronic postoperative pain. Conclusions: The profile of the predominant patient referred to our pain clinic is an older adult, of working age, female, referred from the orthopedics department and with pain in the lumbar region. This described profile is very similar to other pain units in the developed western world. Almost one in 3 patients may suffer from anxiety and / or depression, and post-surgical pain and obesity are also very common.(AU)

Pulse Energy and Pulse Duration Effects in the Ionization and Fragmentation of Iodomethane by Ultraintense Hard X Rays.

The interaction of intense femtosecond x-ray pulses with molecules sensitively depends on the interplay between multiple photoabsorptions, Auger decay, charge rearrangement, and nuclear motion. Here, we report on a combined experimental and theoretical study of the ionization and fragmentation of iodomethane (CH_{3}I) by ultraintense (∼10^{19} W/cm^{2}) x-ray pulses at 8.3 keV, demonstrating how these dynamics depend on the x-ray pulse energy and duration. We show that the timing of multiple ionization steps leading to a particular reaction product and, thus, the product's final kinetic energy, is determined by the pulse duration rather than the pulse energy or intensity. While the overall degree of ionization is mainly defined by the pulse energy, our measurement reveals that the yield of the fragments with the highest charge states is enhanced for short pulse durations, in contrast to earlier observations for atoms and small molecules in the soft x-ray domain. We attribute this effect to a decreased charge transfer efficiency at larger internuclear separations, which are reached during longer pulses.

Outbreak of Pseudomonas aeruginosa infections after CT-guided spinal injections.

BACKGROUND: Meningitis and spinal infections with Gram-negative bacteria after local injections for treatment of chronic back pain are rare. This study investigated an outbreak of Pseudomonas aeruginosa infections following computed tomography (CT)-guided spinal injections (SI). METHODS: A case was defined as a spinal infection or meningitis with P. aeruginosa after SI between 10th January and 1st March 2019 in the same outpatient clinic. Patients without microbiological evidence of P. aeruginosa but with a favourable response to antimicrobial therapy active against P. aeruginosa were defined as probable cases. FINDINGS: Twenty-eight of 297 patients receiving CT-guided SI during the study period developed meningitis or spinal infections. Medical records were available for 19 patients. In 15 patients, there was microbiological evidence of P. aeruginosa, and four patients were defined as probable cases. Two of 19 patients developed meningitis, while the remaining 17 patients developed spinal infections. The median time from SI to hospital admission was 8 days (interquartile range 2-23 days). Patients mainly presented with back pain (N=18; 95%), and rarely developed fever (N=3; 16%). Most patients required surgery (N=16; 84%). Seven patients (37%) relapsed and one patient died. Although the source of infection was not identified microbiologically, documented failures in asepsis when performing SI probably contributed to these infections. CONCLUSIONS: SI is generally considered safe, but non-adherence to asepsis can lead to deleterious effects. Spinal infections caused by P. aeruginosa are difficult to treat and have a high relapse rate.

HIV DNA reservoir and elevated PD-1 expression of CD4 T-cell subsets particularly persist in the terminal ileum of HIV-positive patients despite cART.

OBJECTIVES: Despite its importance as an HIV anatomic sanctuary, little is known about the characteristics of the HIV reservoir in the terminal ileum (TI). In blood, the immune checkpoint inhibitor programmed-death-1 (PD-1) has been linked to the HIV reservoir and T-cell immune dysfunction. We thus evaluated PD-1 expression and cell-associated HIV DNA in memory CD4 T-cell subsets from TI, peripheral blood (PB) and rectum (RE) of untreated and treated HIV-positive patients to identify associations between PD-1 and HIV reservoir in other sites. METHODS: Using mononuclear cells from PB, TI and RE of untreated HIV-positive (N = 6), treated (n = 18) HIV-positive and uninfected individuals (n = 16), we identified and sorted distinct memory CD4 T-cell subsets by flow cytometry, quantified their cell-associated HIV DNA using quantitative PCR and assessed PD-1 expression levels using geometric mean fluorescence intensity. Combined HIV-1 RNA in situ hybridization and immunohistochemistry was performed on ileal biopsy sections. RESULTS: Combined antiretroviral therapy (cART)-treated patients with undetectable HIV RNA and significantly lower levels of HIV DNA in PB showed particularly high PD-1 expression in PB and TI, and high HIV DNA levels in TI, irrespective of clinical characteristics. By contrast, in treatment-naïve patients HIV DNA levels in memory CD4 T-cell subsets were high in PB and TI. CONCLUSION: Elevated PD-1 expression on memory CD4 T-cells in PB and TI despite treatment points to continuous immune dysfunction and underlines the importance of evaluating immunotherapy in reversing HIV latency and T-cell reconstitution. As HIV DNA particularly persists in TI despite cART, investigating samples from TI is crucial in understanding HIV immunopathogenesis.

[Prevalence of SARS-CoV-2 in children from a cohort of 2192 patients]. / Prävalenz von SARS-CoV-2 bei Kindern in einer Kohorte von 2192 Patienten.

BACKGROUND: As of 18 June 2020 a total of 187,764 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections were reported in Germany and of these 6.9% were under the age of 19 years. There were initial indications that children are often asymptomatic and show a milder clinical course. OBJECTIVE: The aim of this study was to gain information on the prevalence of SARS-CoV­2 infections in a pediatric cohort. MATERIAL AND METHODS: Between 13 March and 18 June 2020 all children from whom a smear for SARS-CoV­2 was taken either to rule out an infection or as a suspected case were included. Data were collected on standardized patient record sheets. The analysis of data was anonymized and retrospective. RESULTS: During the given period 2192 children were investigated and 37 patients tested positive (1.7%) for SARS-CoV­2. Of these 36/37 were suspected cases and 28/37 were symptomatic. The leading symptoms were dry cough, runny nose and fever and three children had to be hospitalized. None showed a difficult course of the disease. Among those tested 505 were patients at risk due to an underlying chronic disease, 3 of whom (0.6%) were tested positive with an asymptomatic or mild course. CONCLUSION: We can confirm the first data showing that children and adolescents often have an asymptomatic or mild clinical course of infection or disease. We found no evidence of a high grey area of SARS-CoV­2 infections in this regional pediatric cohort.

Predictors of serofast state after treatment for early syphilis in HIV-infected patients.

OBJECTIVES: Non-treponemal serological tests are used to monitor treatment response during syphilis infection. Syphilis- and HIV-coinfected patients may experience incomplete resolution in non-treponemal titres, which is referred to as the serofast state. The goal of this study was to evaluate risk factors for serofast state in HIV-infected patients. METHODS: From November 2015 to June 2018, 1530 HIV-positive patients were tested for syphilis using a Treponema pallidum particle agglutination (TPPA) assay. Among TPPA-positive patients, medical records were reviewed for early syphilis infection. Serofast state was defined as a less than four-fold decrease in non-treponemal antibody titres during a 6-month follow-up period in the absence of symptoms of syphilis. Baseline characteristics were tested as predictive factors of serological response. RESULTS: In all, 515 patients (33.7%) tested positive in TPPA assays, and in 163 patients at least one previous syphilis infection was documented. A total of 61 out of 163 patients (37.4%) were in a serofast state. A history of previous syphilis infection (61 vs. 43%; P = 0.04) was more common in serofast patients than in patients with serological cure after 6 months. Non-treponemal titres ≥ 1:32 before therapy (47 vs. 25%; P = 0.005) and adjunctive corticosteroids to prevent the Jarisch-Herxheimer reaction (35% vs 15%; P = 0.006) were associated with serological cure after 6 months, but corticosteroid therapy had no influence at 12 months. The intensity of syphilis treatment did not affect serological cure. CONCLUSION: Corticosteroids for prevention of the Jarisch-Herxheimer reaction were associated with earlier serological cure. Although serological response is the accredited surrogate method to monitor syphilis treatment, the biological significance of the serofast state remains unclear.

Menoci: lightweight extensible web portal enhancing data management for biomedical research projects.

BACKGROUND: Biomedical research projects deal with data management requirements from multiple sources like funding agencies' guidelines, publisher policies, discipline best practices, and their own users' needs. We describe functional and quality requirements based on many years of experience implementing data management for the CRC 1002 and CRC 1190. A fully equipped data management software should improve documentation of experiments and materials, enable data storage and sharing according to the FAIR Guiding Principles while maximizing usability, information security, as well as software sustainability and reusability. RESULTS: We introduce the modular web portal software menoci for data collection, experiment documentation, data publication, sharing, and preservation in biomedical research projects. Menoci modules are based on the Drupal content management system which enables lightweight deployment and setup, and creates the possibility to combine research data management with a customisable project home page or collaboration platform. CONCLUSIONS: Management of research data and digital research artefacts is transforming from individual researcher or groups best practices towards project- or organisation-wide service infrastructures. To enable and support this structural transformation process, a vital ecosystem of open source software tools is needed. Menoci is a contribution to this ecosystem of research data management tools that is specifically designed to support biomedical research projects.

[Career Prospects for Young Physicians in Infectious Diseases]. / Perspektiven für junge Ärztinnen und Ärzte in der Infektiologie.

Infectious Diseases are a cross-sectional area connected to various medical disciplines and offer interested physicians multiple working opportunities. The spectrum of infectious diseases covers both out- and inpatient care as well as basic, clinical and epidemiological research. The need for infectious diseases specialists is increasing, thus career prospects are promising. Working conditions in infectious diseases are comparatively family-friendly. With this article we intend to arouse interest for working in the fascinating fields of infectious diseases and provide information on career opportunities. Data from a recently conducted survey among members of the German Society of Infectious Diseases deliver insight, how infectious disease specialists work today.

Leaf:wood allometry and functional traits together explain substantial growth rate variation in rainforest trees.

Plant growth rates drive ecosystem productivity and are a central element of plant ecological strategies. For seedlings grown under controlled conditions, a large literature has firmly identified the functional traits that drive interspecific variation in growth rate. For adult plants, the corresponding knowledge is surprisingly poorly understood. Until recently it was widely assumed that the key trait drivers would be the same (e.g. specific leaf area, or SLA), but an increasing number of papers has demonstrated this not to be the case, or not generally so. New theory has provided a prospective basis for understanding these discrepancies. Here we quantified relationships between stem diameter growth rates and functional traits of adult woody plants for 41 species in an Australian tropical rainforest. From various cost-benefit considerations, core predictions included that: (i) photosynthetic rate would be positively related to growth rate; (ii) SLA would be unrelated to growth rate (unlike in seedlings where it is positively related to growth); (iii) wood density would be negatively related to growth rate; and (iv) leaf mass:sapwood mass ratio (LM:SM) in branches (analogous to a benefit:cost ratio) would be positively related to growth rate. All our predictions found support, particularly those for LM:SM and wood density; photosynthetic rate was more weakly related to stem diameter growth rates. Specific leaf area was convincingly correlated to growth rate, in fact negatively. Together, SLA, wood density and LM:SM accounted for 52 % of variation in growth rate among these 41 species, with each trait contributing roughly similar explanatory power. That low SLA species can achieve faster growth rates than high SLA species was an unexpected result but, as it turns out, not without precedent, and easily understood via cost-benefit theory that considers whole-plant allocation to different tissue types. Branch-scale leaf:sapwood ratio holds promise as an easily measurable variable that may help to understand growth rate variation. Using cost-benefit approaches teamed with combinations of leaf, wood and allometric variables may provide a path towards a more complete understanding of growth rates under field conditions.

[Modern HIV treatment]. / Moderne HIV-Therapie.

Human immunodeficiency virus (HIV) infection has become a chronic disease with a favourable prognosis if adequate antiretroviral therapy (ART) is applied. Therefore, each patient with HIV infection should be treated irrespectively of clinical symptoms or of immunological status. A combination of three active drugs that have to be taken life-long has been standard for many years. The regimen contains two nucleoside reverse transcriptase inhibitors plus either an integrase inhibitor, a boosted protease inhibitor, or a non-nucleoside reverse transcriptase inhibitor. Integrase inhibitors are recommended as the third partner of choice by recent guidelines due to their high efficacy and their favourable safety profile. Many combination drugs are now available which allow a simple treatment with few tablets and in many instances a one-pill combination per day is an option. Potential interactions with drugs given for other diseases have to be taken into account, especially if a pharmacological booster is part of the regimen. Combination therapy should be changed if either virological failure (HIV RNA >200 copies/ml) or drug-related adverse events occur. In special situations (e. g. pregnancy) highly experienced experts in the field should be consulted. Novel approaches for HIV therapy include dual therapy as well as treatment with long-acting substances. Beside therapy, antiretroviral drugs are used for prevention either as post-exposure prophylaxis or as pre-exposure prophylaxis.

Impact of patient handover structure on neonatal perioperative safety.

OBJECTIVE: To compare the incidence, severity, preventability, and contributing factors of non-routine events-deviations from optimal care based on the clinical situation-associated with team-based, nurse-to-nurse, and mixed handovers in a large cohort of surgical neonates. STUDY DESIGN: A prospective observational study and one-time cross-sectional provider survey were conducted at one urban academic children's hospital. 130 non-cardiac surgical cases in 109 neonates who received pre- and post-operative NICU care. RESULTS: The incidence of clinician-reported NREs was high (101/130 cases, 78%) but did not differ significantly across acuity-tailored neonatal handover practices. National Surgical Quality Improvement-Pediatric occurrences of major morbidity were significantly higher (p < 0.001) in direct team handovers than indirect nursing or mixed handovers. CONCLUSIONS: NREs occur at a high rate and are of variable severity in neonatal perioperative care. NRE rates and contributory factors were homogenous across handover types. Surveyed clinicians recommend structured handovers for all patients at every transfer point regardless of acuity.

Pretreatment human immunodeficiency virus type 1 (HIV-1) drug resistance in transmission clusters of the Cologne-Bonn region, Germany.

OBJECTIVES: In Germany, previous reports have demonstrated transmitted human immunodeficiency virus type 1 (HIV-1) drug-resistance mutations (DRM) in 11% of newly diagnosed individuals, highlighting the importance of drug-resistance screening before the initiation of antiretroviral therapy (ART). Here, we sought to understand the molecular epidemiology of HIV DRM transmission in the Cologne-Bonn region of Germany, given one of the highest rates of new HIV diagnoses in western Europe (13.7 per 100 000 habitants). METHODS: We analysed 714 HIV-1 ART-naive infected individuals diagnosed at the University Hospitals Cologne and Bonn between 2001 and 2016. Screening for DRM was performed according to the Stanford University Genotypic Resistance Interpretation. Shared DRM were defined as any DRM present in genetically linked individuals (<1.5% genetic distance). Phylogenetic and network analyses were performed to infer putative relationships and shared DRM. RESULTS: The prevalence of any DRM at time of diagnosis was 17.2% (123/714 participants). Genetic transmission network analyses showed comparable frequencies of DRM in clustering versus non-clustering individuals (17.1% (85/497) versus 17.5% (38/217)). The observed rate of DRM in the region was higher than previous reports 10.8% (87/809) (p < 0.001), revealing the need to reduce onward transmission in this area. Genetically linked individuals harbouring shared DRM were more likely to live in suburban areas (24/38) than in central Cologne (1/38) (p < 0.001). CONCLUSION: The rate of DRM was exceptionally high. Network analysis elucidated frequent cases of shared DRM among genetically linked individuals, revealing the potential spread of DRM and the need to prevent onward transmission of DRM in the Cologne-Bonn area.

To prescribe, or not to prescribe: decision making in HIV-1 post-exposure prophylaxis.

OBJECTIVES: We investigated the trend in usage of post-exposure prophylaxis (PEP) after HIV-1 risk exposure and evaluated PEP prescription decision making of physicians according to guidelines. METHODS: All PEP consultations from January 2014 to December 2016 in patients presenting at the University Hospital of Cologne (Germany) were retrospectively analysed. HIV risk contacts included sexual and occupational exposure. The European AIDS Clinical Society (EACS) Guidelines for HIV PEP (version 9.0, 2017) were used for assessment. RESULTS: A total of 649 patients presented at the emergency department (ED) or the clinic for infectious diseases (IDC) for PEP consultations. A continuous increase in the number of PEP requests was recorded: 189 in 2014, 208 in 2015 and 252 in 2016. PEP consultations in men who have sex with men (MSM) showed a remarkable increase in 2016 (2014, n = 96; 2015, n = 101; 2016, n = 152). Decisions taken by physicians with a specialization in infectious diseases (n = 547) included 61 (11%) guideline-discordant prescriptions [2014: 14% (n = 22); 2015: 9% (n = 16); 2016: 11% (n = 23)]. Among these, sexual exposure accounted for 45 (74%) cases, including 15 cases of nonconsensual sex, while occupational exposure accounted for 14 (23%) cases and other exposure two cases (3%). The main reason for guideline-discordant PEP prescriptions was emotional stress of the patient (n = 37/61). CONCLUSIONS: PEP prescriptions are increasing and decision making is influenced by patients' emotional stress, but PEP prescriptions should be strictly administered according to risk assessment.

Bowl shaped deformation in a planar aromatic polycycle upon reduction. Li and Na separated dianions of the aromatic polycycle 5,6:11,12-di-o-phenylene-tetracene.

Herein we report the synthesis and crystal structures of three light alkali metal salts of the dianion of the polycyclic aromatic hydrocarbon 5,6:11,12-di-o-phenylenetetracene (LDOPT). The compounds are obtained by reaction of LDOPT with an excess of lithium or sodium metal in different O-donor solvents (DME, diglyme) and crystallize as naked, solvated-cation separated dianions exhibiting no interaction between the alkali metal ion and the aromatic π-system of LDOPT. Depending on the aprotic etheral solvent and the hardness of the alkaline metal agent a significant structural perturbation of the conjugated carbon framework of LDOPT is observed resulting in a bowl shaped curvature of the anionic π-perimeter, in contrast to its fully planar neutral state. Reduction of LDOPT with lithium in DME results in the formation of the solvent-separated molecular structure of {[(DME-κ2O)3Li+]2(LDOPT2-)}21 containing naked isolated units of dianionic LDOPT. A similar structural arrangement is observed for the corresponding sodium compound {[(DME-κ2O)3Na+]2(LDOPT2-)}22 in which, however, a lesser curvature of the isolated dianionic ligand skeleton compared to 1 is observed. In contrast to 1 and 2 reduction with sodium in diglyme results in the formation of {[(diglyme-κ3O)2Na+]2(LDOPT2-)}0.53. The deformation of the peripheric phenylene rings of [LDOPT2-] in 3 is not as pronounced as compared to 1 and 2. Nevertheless, molecular structures of 1-3 deviate from full-planarity as observed in the parent neutral LDOPT. No preferential endo- or exo-site coordination of the alkaline metal cations Li+ and Na+ on the curved dianionic π-perimeter is observed.

Organometallic rubidium and cesium compounds of the 5,6;11,12-di-o-phenylene-tetracene dianion.

Twofold reduction of the title molecule 5,6;11,12-di-o-phenylenetetracene (DOPT) with an excess of metallic rubidium and cesium in the presence of strongly coordinating ethers like 18-crown-6-ether (18C6) and tetraglyme results in the formation of the first Rb(i) triple-decker complex and the first Cs(i) coordination polymer of the so far only sparsely studied polyaromatic planar hydrocarbon DOPT. Both compounds are extremely sensitive towards air and water in solution as well as in the solid state. Both compounds exhibit isomerism within their crystal lattices.

Femtosecond response of polyatomic molecules to ultra-intense hard X-rays.

X-ray free-electron lasers enable the investigation of the structure and dynamics of diverse systems, including atoms, molecules, nanocrystals and single bioparticles, under extreme conditions. Many imaging applications that target biological systems and complex materials use hard X-ray pulses with extremely high peak intensities (exceeding 1020 watts per square centimetre). However, fundamental investigations have focused mainly on the individual response of atoms and small molecules using soft X-rays with much lower intensities. Studies with intense X-ray pulses have shown that irradiated atoms reach a very high degree of ionization, owing to multiphoton absorption, which in a heteronuclear molecular system occurs predominantly locally on a heavy atom (provided that the absorption cross-section of the heavy atom is considerably larger than those of its neighbours) and is followed by efficient redistribution of the induced charge. In serial femtosecond crystallography of biological objects-an application of X-ray free-electron lasers that greatly enhances our ability to determine protein structure-the ionization of heavy atoms increases the local radiation damage that is seen in the diffraction patterns of these objects and has been suggested as a way of phasing the diffraction data. On the basis of experiments using either soft or less-intense hard X-rays, it is thought that the induced charge and associated radiation damage of atoms in polyatomic molecules can be inferred from the charge that is induced in an isolated atom under otherwise comparable irradiation conditions. Here we show that the femtosecond response of small polyatomic molecules that contain one heavy atom to ultra-intense (with intensities approaching 1020 watts per square centimetre), hard (with photon energies of 8.3 kiloelectronvolts) X-ray pulses is qualitatively different: our experimental and modelling results establish that, under these conditions, the ionization of a molecule is considerably enhanced compared to that of an individual heavy atom with the same absorption cross-section. This enhancement is driven by ultrafast charge transfer within the molecule, which refills the core holes that are created in the heavy atom, providing further targets for inner-shell ionization and resulting in the emission of more than 50 electrons during the X-ray pulse. Our results demonstrate that efficient modelling of X-ray-driven processes in complex systems at ultrahigh intensities is feasible.