Polaritonic Feshbach resonance

A Feshbach resonance occurs when the energy of two interacting free particles comes into resonance with a molecular bound state. When approaching this resonance, marked changes in the interaction strength between the particles can arise. Feshbach resonances provide a powerful tool for controlling the interactions in ultracold atomic gases, which can be switched from repulsive to attractive and have allowed a range of many-body quantum physics effects to be explored. Here we demonstrate a Feshbach resonance based on the polariton spinor interactions in a semiconductor microcavity. By tuning the energy of two polaritons with anti-parallel spins across the biexciton bound state energy, we show an enhancement of attractive interactions and a prompt change to repulsive interactions. A mean-field two-channel model quantitatively reproduces the experimental results. This observation paves the way for a new tool for tuning polariton interactions and to move forward into quantum correlated polariton physics

β-Nitroso-o-Quinone Methides: Potent Intermediates in Organic Chemistry and Biology : The impact of the NO group on their Structure and Reactivity Profile: a Theoretical Insight

The structure and reactivity profile of prototype o-quinone methides 1, 2 and their ß-nitroso analogues 6-9 have been investigated by means of DFT and MP2 calculations. These highly reactive unstable species are generated by oxidative dearomatization of their precursor oximes. The destabilization of their structure is more pronounced in the ß-nitroso congeners 7-9. There is only a weak π conjugation across the nitrosoalkene arm. The latter gives rise to E and Z conformations and causes some distortion on the ring -frame while the π-frame is weakly perturbed. The Z conformation is the most stable in all structures. Their geometry is also affected by the o-quinone ring and the 1,2-(7 and 8) and 2,3-(9) isomer pattern. The stability of these conformations is rationalized in terms of ortho- or peri- ring formations. The impact of their geometry profile on their reactivity pattern has been studied by means of reactivity descriptors such as Fukui function f(r), chemical potential and hardness, HOMO and LUMO energies and their separation (HOMO-LUMO gap) as well as aromaticity indices such as HOMA and out-of-plane deformability. All descriptors consistently demonstrate that the reactivity is dominated by an intramolecular ortho or peri-cyclization mode to fused 1,2-oxazoles or 1,2-oxazines, respectively. Intermolecular primary reactions can occur at the quinone alkene bond or that of the nitrosoalkene arm.Peer reviewe

HIV, syphilis, and hepatitis B and C prevalence among patients with mental illness: a review of the literature Prevalência de infecção por HIV, sífilis e hepatite B e C entre portadores de doenças mentais crônicas

A limited number of studies worldwide have investigated the prevalence of HIV, syphilis, and hepatitis B and C infection among psychiatric patients. However, prevalence of these infections in the population with chronic mental illness has not been clearly established. Most of the published papers are from developed countries and have derived from relatively small and non-representative samples. We performed a systematic review of the published literature to identify studies on these infectious diseases within psychiatric populations in Brazil and other developing countries. Overall, prevalence rates varied from 0% to 29% for HIV; 1.6% to 66% for HBV; 0.4% to 38% for HCV; and 1.1% to 7.6% for syphilis. Several risk factors were identified and discussed, although sampling limitations restrict the generalization of study findings. This review highlights the lack of information on the prevalence of sexually transmitted diseases and their associated factors among persons with chronic mental illness and identifies gaps in the knowledge base in both developing and developed countries.<br>Os portadores de doenças mentais crônicas encontram-se em risco para a infecção pelo HIV e outras infecções sexualmente transmissíveis. Entretanto, a prevalência dessas infecções entre portadores de doença mental crônica ainda não está claramente estabelecida nesta população. A maioria dos trabalhos sobre o tema foi conduzida em países desenvolvidos, com amostras relativamente pequenas e não representativas. Foi realizada uma revisão sistemática da literatura para identificar estudos sobre a prevalência do HIV, sífilis, hepatite B e C entre pacientes com doença mental crônica no Brasil e no mundo. De um modo geral, as prevalências variaram de 0% a 29%, 3 a 66%, 0,4 a 38% e 3,3% a 7,6% para HIV, hepatite B, hepatite C e sífilis, respectivamente. Vários fatores de risco foram identificados e discutidos, embora a literatura atual não demonstre achados significativos gerados por estudos representativos. Tal revisão destaca a escassez de informação sobre a prevalência de infecções sexualmente transmitidas e seus fatores associados entre portadores de doenças mentais crônicas e identifica lacunas no conhecimento atual em países desenvolvidos bem como nos em desenvolvimento

Brain aging in major depressive disorder: results from the ENIGMA major depressive disorder working group

Major depressive disorder (MDD) is associated with an increased risk of brain atrophy, aging-related diseases, and mortality. We examined potential advanced brain aging in adult MDD patients, and whether this process is associated with clinical characteristics in a large multicenter international dataset. We performed a mega-analysis by pooling brain measures derived from T1-weighted MRI scans from 19 samples worldwide. Healthy brain aging was estimated by predicting chronological age (18–75 years) from 7 subcortical volumes, 34 cortical thickness and 34 surface area, lateral ventricles and total intracranial volume measures separately in 952 male and 1236 female controls from the ENIGMA MDD working group. The learned model coefficients were applied to 927 male controls and 986 depressed males, and 1199 female controls and 1689 depressed females to obtain independent unbiased brain-based age predictions. The difference between predicted “brain age” and chronological age was calculated to indicate brain-predicted age difference (brain-PAD). On average, MDD patients showed a higher brain-PAD of +1.08 (SE 0.22) years (Cohen’s d = 0.14, 95% CI: 0.08–0.20) compared with controls. However, this difference did not seem to be driven by specific clinical characteristics (recurrent status, remission status, antidepressant medication use, age of onset, or symptom severity). This highly powered collaborative effort showed subtle patterns of age-related structural brain abnormalities in MDD. Substantial within-group variance and overlap between groups were observed. Longitudinal studies of MDD and somatic health outcomes are needed to further assess the clinical value of these brain-PAD estimates