Arene oxidation with malonoyl peroxides

Malonoyl peroxide 7, prepared in a single step from the commercially available diacid, is an effective reagent for the oxidation of aromatics. Reaction of an arene with peroxide 7 at room temperature leads to the corresponding protected phenol which can be unmasked by aminolysis. An ionic mechanism consistent with the experimental findings and supported by isotopic labeling, Hammett analysis, EPR investigations and reactivity profile studies is proposed

On the dynamics of a nonlinear energy harvester with multiple resonant zones

The dynamics of a nonlinear vibration energy harvester for rotating systems is investigated analytically through harmonic balance, as well as by numerical analysis. The electromagnetic harvester is attached to a spinning shaft at constant speed. Magnetic levitation is used as the system nonlinear restoring force for broadening the resonant range of the oscillator. The system is modelled as a Duffing oscillator with linear frequency variation under static, as well as harmonic excitation. Behaviour charts and backbone curves are extracted for the fundamental harmonic response and validated against frequency response curves for selected cases, using direct numerical integration. It is found that variation in stiffness, together with asymmetric forcing, gives rise to a novel structure of multiple resonant zones, incorporating mono-stable and bi-stable dynamics. Contrary to previously considered bi-stable energy harvesters, cross-well oscillations are realized through a transition from single-well potential energy to double-well with forward frequency sweep. Furthermore, in-well_oscillations present a hardening behaviour, unlike the well-known softening in-well response of bi-stable Duffing oscillators. The analysis shows that the proposed system has multiple resonant responses to a frequency sweep, influenced by consecutive interacting backbone curves similar to a multi-modal system. This combined effect of the transition to bi-stable dynamics and the hardening in-well oscillations induces resonant response of the harvester over multiple distinct frequency ranges. Thus, the system exhibits a broadened frequency response, enhancing its energy harvesting potential

Pre-migration traumatic experiences, post-migration perceived discrimination and substance use among Russian and Kurdish migrants-a population-based study

Background and aims The associations between traumatic events, substance use and perceived discrimination have been rarely studied among migrants in host countries. We examined whether pre-migration potentially traumatic experiences (PTEs) or perceived discrimination (PD) are associated with substance use among migrants with voluntary (Russians) and forced (Kurds) migration backgrounds. Design Cross-sectional interview and health examination data from the Finnish Migrant Health and Wellbeing Study were used. The target sample (n = 1000 for each group) was drawn from the national population register using stratified random sampling by participants' country of birth and native language. Setting Population-based data were collected from six cities in Finland during 2010-12. Participants The participation rates were 68% (Russians) and 59% (Kurds). The analytical sample size varied (Russians n = 442-687, Kurds n = 459-613), as some participants completed only interview, health examination or short interview. The majority of Kurds had a refugee background (75%) while Russians had mainly migrated for other reasons (99%). Measurements The three main outcomes were self-reported binge drinking, daily smoking and life-time cannabis use. PTEs and PD were self-reported in the interview. Socio-demographic background, migration-related factors and current affective symptoms were adjusted for. Findings Among Kurds, PTEs were associated with binge drinking [adjusted odds ratio (aOR) = 2.65, 95% confidence interval (CI) = 1.30-5.42] and PD was associated with life-time cannabis use (aOR = 3.89, 95% CI = 1.38-10.97) after adjusting for contextual factors. Among Russians, PTEs were associated with life-time cannabis use adjusting for contextual factors (aOR = 2.17, 95% CI = 1.12-4.18). Conclusions In Finland, pre-migration traumatic experiences appear to be associated with life-time cannabis use among the Russian migrant population (voluntary migration) and binge drinking among the Kurdish migrant population (forced migration). Perceived discrimination in Finland appears to be associated with life-time cannabis use among Kurdish migrants.Peer reviewe

de Sitter spacetime: effects of metric perturbations on geodesic motion

Gravitational perturbations of the de Sitter spacetime are investigated using the Regge--Wheeler formalism. The set of perturbation equations is reduced to a single second order differential equation of the Heun-type for both electric and magnetic multipoles. The solution so obtained is used to study the deviation from an initially radial geodesic due to the perturbation. The spectral properties of the perturbed metric are also analyzed. Finally, gauge- and tetrad-invariant first-order massless perturbations of any spin are explored following the approach of Teukolsky. The existence of closed-form, i.e. Liouvillian, solutions to the radial part of the Teukolsky master equation is discussed.Comment: IOP macros, 10 figure

A diagnostic dilemma between psychosis and post-traumatic stress disorder: a case report and review of the literature

<p>Abstract</p> <p>Introduction</p> <p>Post-traumatic stress disorder is defined as a mental disorder that arises from the experience of traumatic life events. Research has shown a high incidence of co-morbidity between post-traumatic stress disorder and psychosis.</p> <p>Case presentation</p> <p>We report the case of a 32-year-old black African woman with a history of both post-traumatic stress disorder and psychosis. Two years ago she presented to mental health services with auditory and visual hallucinations, persecutory delusions, suicidal ideation, recurring nightmares, hyper-arousal, and initial and middle insomnia. She was prescribed trifluoperazine (5 mg/day) and began cognitive-behavioral therapy for psychosis. Her psychotic symptoms gradually resolved over a period of three weeks; however, she continues to experience ongoing symptoms of post-traumatic stress disorder. In our case report, we review both the diagnostic and treatment issues regarding post-traumatic stress disorder with psychotic symptoms.</p> <p>Conclusions</p> <p>There are many factors responsible for the symptoms that occur in response to a traumatic event, including cognitive, affective and environmental factors. These factors may predispose both to the development of post-traumatic stress disorder and/or psychotic disorders. The independent diagnosis of post-traumatic stress disorder with psychotic features remains an open issue. A psychological formulation is essential regarding the appropriate treatment in a clinical setting.</p

Oxidative modification of low-density lipoproteins and the outcome of renal allografts at 11/2 years

Oxidative modification of low-density lipoproteins and the outcome of renal allografts at 11/2 years.BackgroundPrevious studies reported a significant association between hyperlipidemia of the recipient and chronic allograft nephropathy (CAN). However, the nature and the pathogenic mechanism of circulating lipid abnormalities in CAN remain unclear.MethodsIn a prospective study of 50 consecutive adult recipients of a cadaveric renal allograft, we investigated the impact of lipid abnormalities on the outcome of the graft at 11/2 years. Besides morphometric analysis of implantation and protocol biopsies, clinical and biochemical variables were studied at three-month intervals. Plasma concentrations of oxidized low-density lipoprotein (OxLDL) were determined by means of enzyme-linked immunosorbent assay. Immunohistochemical staining for OxLDL and macrophages was performed on paired renal biopsies. Study end points were the fractional interstitial volume and the 24-hour creatinine clearance at 11/2 years.ResultsHigh-density lipoprotein (HDL) cholesterol of the recipient ≤47 mg/dL was a risk factor for the functional (RR = 1.56; 95% CI, 0.978 to 2.497) and the morphological (RR = 2.75; 95% CI, 1.075 to 7.037) outcome of the graft, mainly in patients without acute rejection (RR = 2.03; 95% CI, 1.13 to 3.65, and RR = 4.67; 95% CI, 1.172 to 18.582, respectively). Interstitial accumulation of OxLDL was inversely associated with HDL cholesterol (R = -0.476, P = 0.019), and was associated with a higher density of tubulointerstitial macrophages (R = 0.656, P = 0.001) and a higher fractional interstitial volume at 11/2 years (P = 0.049).ConclusionDecreased HDL cholesterol levels of the recipient adversely affect the outcome of renal allografts through the accumulation of OxLDL in the renal interstitium of the graft. Interstitial accumulation of OxLDL was associated with the presence of macrophages and the development of interstitial fibrosis

Machine learning prediction of progressive subclinical myocardial dysfunction in moderate aortic stenosis

BackgroundModerate severity aortic stenosis (AS) is poorly understood, is associated with subclinical myocardial dysfunction, and can lead to adverse outcome rates that are comparable to severe AS. Factors associated with progressive myocardial dysfunction in moderate AS are not well described. Artificial neural networks (ANNs) can identify patterns, inform clinical risk, and identify features of importance in clinical datasets.MethodsWe conducted ANN analyses on longitudinal echocardiographic data collected from 66 individuals with moderate AS who underwent serial echocardiography at our institution. Image phenotyping involved left ventricular global longitudinal strain (GLS) and valve stenosis severity (including energetics) analysis. ANNs were constructed using two multilayer perceptron models. The first model was developed to predict change in GLS from baseline echocardiography alone and the second to predict change in GLS using data from baseline and serial echocardiography. ANNs used a single hidden layer architecture and a 70%:30% training/testing split.ResultsOver a median follow-up interval of 1.3 years, change in GLS (≤ or &gt;median change) could be predicted with accuracy rates of 95% in training and 93% in testing using ANN with inputs from baseline echocardiogram data alone (AUC: 0.997). The four most important predictive baseline features (reported as normalized % importance relative to most important feature) were peak gradient (100%), energy loss (93%), GLS (80%), and DI &lt; 0.25 (50%). When a further model was run including inputs from both baseline and serial echocardiography (AUC 0.844), the top four features of importance were change in dimensionless index between index and follow-up studies (100%), baseline peak gradient (79%), baseline energy loss (72%), and baseline GLS (63%).ConclusionsArtificial neural networks can predict progressive subclinical myocardial dysfunction with high accuracy in moderate AS and identify features of importance. Key features associated with classifying progression in subclinical myocardial dysfunction included peak gradient, dimensionless index, GLS, and hydraulic load (energy loss), suggesting that these features should be closely evaluated and monitored in AS

Tuning Nonlinear Mechanical Mode Coupling in GaAs Nanowires Using Cross-Section Morphology Control.

We investigate the nonlinear mechanical properties of GaAs nanowires with anisotropic cross-section. Fundamental and second order flexural modes are studied using laser interferometry with good agreement found between experiment and theory describing the nonlinear response under mechanical excitation. In particular, we demonstrate that the sign of the nonlinear coupling between orthogonal modes is dependent on the cross-section aspect ratio. The findings are of interest for applications such as amplitude to frequency conversion and vectorial force sensing

A novel isolator-based system promotes viability of human embryos during laboratory processing

In vitro fertilisation (IVF) and related technologies are arguably the most challenging of all cell culture applications. The starting material is a single cell from which one aims to produce an embryo capable of establishing a pregnancy eventually leading to a live birth. Laboratory processing during IVF treatment requires open manipulations of gametes and embryos, which typically involves exposure to ambient conditions. To reduce the risk of cellular stress, we have developed a totally enclosed system of interlinked isolator-based workstations designed to maintain oocytes and embryos in a physiological environment throughout the IVF process. Comparison of clinical and laboratory data before and after the introduction of the new system revealed that significantly more embryos developed to the blastocyst stage in the enclosed isolator-based system compared with conventional open-fronted laminar flow hoods. Moreover, blastocysts produced in the isolator-based system contained significantly more cells and their development was accelerated. Consistent with this, the introduction of the enclosed system was accompanied by a significant increase in the clinical pregnancy rate and in the proportion of embryos implanting following transfer to the uterus. The data indicate that protection from ambient conditions promotes improved development of human embryos. Importantly, we found that it was entirely feasible to conduct all IVF-related procedures in the isolator-based workstations

The Effects of Cocaine on Different Redox Forms of Cysteine and Homocysteine, and on Labile, Reduced Sulfur in the Rat Plasma Following Active versus Passive Drug Injections

Received: 28 November 2012 / Revised: 19 April 2013 / Accepted: 6 May 2013 / Published online: 16 May 2013 The Author(s) 2013. This article is published with open access at Springerlink.comThe aim of the present studies was to evaluate cocaine-induced changes in the concentrations of different redox forms of cysteine (Cys) and homocysteine (Hcy), and products of anaerobic Cys metabolism, i.e., labile, reduced sulfur (LS) in the rat plasma. The above-mentioned parameters were determined after i.p. acute and subchronic cocaine treatment as well as following i.v. cocaine self-administration using the yoked procedure. Additionally, Cys, Hcy, and LS levels were measured during the 10-day extinction training in rats that underwent i.v. cocaine administration. Acute i.p. cocaine treatment increased the total and protein-bound Hcy contents, decreased LS, and did not change the concentrations of Cys fractions in the rat plasma. In turn, subchronic i.p. cocaine administration significantly increased free Hcy and lowered the total and protein-bound Cys concentrations while LS level was unchanged. Cocaine self-administration enhanced the total and protein-bound Hcy levels, decreased LS content, and did not affect the Cys fractions. On the other hand, yoked cocaine infusions did not alter the concentration of Hcy fractions while decreased the total and protein-bound Cys and LS content. This extinction training resulted in the lack of changes in the examined parameters in rats with a history of cocaine self-administration while in the yoked cocaine group an increase in the plasma free Cys fraction and LS was seen. Our results demonstrate for the first time that cocaine does evoke significant changes in homeostasis of thiol amino acids Cys and Hcy, and in some products of anaerobic Cys metabolism, which are dependent on the way of cocaine administration