Exploring the ultrafast and isomer-dependent photodissociation of iodothiophenes via site-selective ionization

C-I bond extension and fission following ultraviolet (UV, 262 nm) photoexcitation of 2- and 3-iodothiophene is studied using ultrafast time-resolved extreme ultraviolet (XUV) ionization in conjunction with velocity map ion imaging. The photoexcited molecules and eventual I atom products are probed by site-selective ionization at the I 4d edge using intense XUV pulses, which induce multiple charges initially localized to the iodine atom. At C-I separations below the critical distance for charge transfer (CT), charge can redistribute around the molecule leading to Coulomb explosion and charged fragments with high kinetic energy. At greater C-I separations, beyond the critical distance, CT is no longer possible and the measured kinetic energies of the charged iodine atoms report on the neutral dissociation process. The time and momentum resolved measurements allow determination of the timescales and the respective product momentum and kinetic energy distributions for both isomers, which are interpreted in terms of rival 'direct' and 'indirect' dissociation pathways. The measurements are compared with a classical over the barrier model, which reveals that the onset of the indirect dissociation process is delayed by ∼1 ps relative to the direct process. The kinetics of the two processes show no discernible difference between the two parent isomers, but the branching between the direct and indirect dissociation channels and the respective product momentum distributions show isomer dependencies. The greater relative yield of indirect dissociation products from 262 nm photolysis of 3-iodothiophene (cf. 2-iodothiophene) is attributed to the different partial cross-sections for (ring-centred) π∗ ← π and (C-I bond localized) σ∗ ← (n/π) excitation in the respective parent isomers.

Ultrafast electronic relaxation pathways of the molecular photoswitch quadricyclane

The light-induced ultrafast switching between molecular isomers norbornadiene and quadricyclane can reversibly store and release a substantial amount of chemical energy. Prior work observed signatures of ultrafast molecular dynamics in both isomers upon ultraviolet excitation but could not follow the electronic relaxation all the way back to the ground state experimentally. Here we study the electronic relaxation of quadricyclane after exciting in the ultraviolet (201 nanometres) using time-resolved gas-phase extreme ultraviolet photoelectron spectroscopy combined with non-adiabatic molecular dynamics simulations. We identify two competing pathways by which electronically excited quadricyclane molecules relax to the electronic ground state. The fast pathway (<100 femtoseconds) is distinguished by effective coupling to valence electronic states, while the slow pathway involves initial motions across Rydberg states and takes several hundred femtoseconds. Both pathways facilitate interconversion between the two isomers, albeit on different timescales, and we predict that the branching ratio of norbornadiene/quadricyclane products immediately after returning to the electronic ground state is approximately 3:2.

Differentiating Three-Dimensional Molecular Structures Using Laser-Induced Coulomb Explosion Imaging

Coulomb explosion imaging (CEI) with x-ray free electron lasers has recently been shown to be a powerful method for obtaining detailed structural information of gas-phase planar ring molecules [R. Boll et al., X-ray multiphoton-induced Coulomb explosion images complex single molecules, Nat. Phys. 18, 423 (2022).NPAHAX1745-247310.1038/s41567-022-01507-0]. In this Letter, we investigate the potential of CEI driven by a tabletop laser and extend this approach to differentiating three-dimensional structures. We study the static CEI patterns of planar and nonplanar organic molecules that resemble the structures of typical products formed in ring-opening reactions. Our results reveal that each molecule exhibits a well-localized and distinctive pattern in three-dimensional fragment-ion momentum space. We find that these patterns yield direct information about the molecular structures and can be qualitatively reproduced using a classical Coulomb explosion simulation. Our findings suggest that laser-induced CEI can serve as a robust method for differentiating molecular structures of organic ring and chain molecules. As such, it holds great promise as a method for following ultrafast structural changes, e.g., during ring-opening reactions, by tracking the motion of individual atoms in pump-probe experiments.

Monitoring the Evolution of Relative Product Populations at Early Times during a Photochemical Reaction

Identifying multiple rival reaction products and transient species formed during ultrafast photochemical reactions and determining their time-evolving relative populations are key steps toward understanding and predicting photochemical outcomes. Yet, most contemporary ultrafast studies struggle with clearly identifying and quantifying competing molecular structures/species among the emerging reaction products. Here, we show that mega-electronvolt ultrafast electron diffraction in combination with ab initio molecular dynamics calculations offer a powerful route to determining time-resolved populations of the various isomeric products formed after UV (266 nm) excitation of the five-membered heterocyclic molecule 2(5H)-thiophenone. This strategy provides experimental validation of the predicted high (∼50%) yield of an episulfide isomer containing a strained three-membered ring within ∼1 ps of photoexcitation and highlights the rapidity of interconversion between the rival highly vibrationally excited photoproducts in their ground electronic state.

True coincidence summing correction for a BEGe detector in close geometry measurements

The true coincidence summing correction factor for a Broad Energy Germanium detector has been calculated at far and close geometry set-up using radioactive γ-ray sources. The correction factors were calculated using both experimental and analytical methods. Geant4 simulation was done to calculate the full-energy peak and total efficiencies of the detector. Standard, as well as fabricated mono-energetic γ-ray sources, were used for the γ-ray efficiency measurements. The simulated efficiencies of mono-energetic γ-ray sources were matched to the experimental γ-ray efficiencies by optimizing the detector parameters. The same parameters were used to obtain the full-energy peak and total efficiencies for γ-rays of current interest. Analytical and experimental correction factors were found to agree well with each other. The coincidence summing effect is found to be significant for source-to-detector distances less than 5 cm.

Ultrafast Roaming Mechanisms in Ethanol Probed by Intense Extreme Ultraviolet Free-Electron Laser Radiation: Electron Transfer versus Proton Transfer

Ultrafast H₂⁺ and H₃⁺ formation from ethanol is studied using pump-probe spectroscopy with an extreme ultraviolet (XUV) free-electron laser. The first pulse creates a dication, triggering H₂ roaming that leads to H₂⁺ and H₃⁺ formation, which is disruptively probed by a second pulse. At photon energies of 28 and 32 eV, the ratio of H₂⁺ to H₃⁺ increases with time delay, while it is flat at a photon energy of 70 eV. The delay-dependent effect is ascribed to a competition between electron and proton transfer. High-level quantum chemistry calculations show a flat potential energy surface for H₂ formation, indicating that the intermediate state may have a long lifetime. The ab initio molecular dynamics simulation confirms that, in addition to the direct emission, a small portion of H₂ undergoes a roaming mechanism that leads to two competing pathways: electron transfer from H₂ to C₂H₄O²⁺ and proton transfer from C₂H₄O²⁺ to H₂.

1218 GREY MATTER VOLUME AND NEUROTRANSMITTER RECEPTORS ABNORMALITIES IN PARKINSON’S DISEASE PSYCHOSIS: A META-ANALYSIS

Introduction

Recent evidence suggests extensive grey matter abnormalities in Parkinson’s Disease Psychosis (PDP), as well as dysfunction of dopaminergic and serotonergic receptors. However, findings remain unclear. This meta-analysis aimed to identify neuroanatomical correlates of PDP and to examine the relationship between grey matter and key candidate receptors.

Method

Peak coordinates were extracted from structural magnetic resonance imaging (MRI) studies (identified through systematic searches on PubMed, Web of Science, and Embase) for PDP patients and Parkinson's Disease patients without psychosis (PDnP) and were analysed using Seed-based d mapping with permutation of subject images (SDM-PSI). Gene expression data for dopaminergic (D1/D2) and serotonergic (5-HT2a/5-HT1a) receptors were extracted from the Allen Human Brain Atlas, probe-to-gene re-annotation data were downloaded from Arnatkevic̆iūtė et al. (Neuroimage, 2019;189:353-67) and parcellated on 78 regions of the Desikan-Killiany brain atlas. Effect-size estimates, extracted from the SDM-PSI analysis for these 78 regions as a measure of grey matter in PDP patients, were entered in multiple regression models.

Results

10 studies were included in the meta-analysis (PDP, n= 211; mean age = 69.01 years, 52.1% males; PDnP, n = 298, mean age = 67.34 years, 41.9 % males). Reduction in grey matter was observed in parieto-temporo-occipital regions in PDP patients (uncorrected, p &lt; 0.05). When controlling for PD medications, expressed in Levodopa equivalent daily dose (LEDD), results remained significant (uncorrected, p &lt; 0.05). 5-HT2a and 5-HT1a gene receptor expressions were associated with estimates of grey matter volume (5-HT2a, b=-0.20, p=0.01, adjusted for LEDD, b=-0.18, p=0.03; 5-HT1a, b=0.11, p=0.02, adjusted for LEDD, b=0.12, p=0.01).

Conclusion

We observed lower cortical volume in parieto-temporo-occipital areas, which are involved in information processing, integration, and attention in PDP compared to PDnP patients. We also reported an association between regional brain expression of serotonergic receptors and grey matter volume suggesting a role of serotonin in PDP.

Strong-Field-Induced Coulomb Explosion Imaging of Tribromomethane

The Coulomb explosion of tribromomethane (bromoform, CHBr₃) induced by 28 fs near-infrared laser pulses is investigated by three-dimensional coincidence ion momentum imaging. We focus on the fragmentation into three, four, and five ionic fragments measured in coincidence and present different ways of visualizing the three-dimensional momentum correlations. We show that the experimentally observed momentum correlations for 4- and 5-fold coincidences are well reproduced by classical Coulomb explosion simulations and contain information about the structure of the parent molecule that could be used to differentiate structural isomers formed, for example, in a pump-probe experiment. Our results thus provide a clear path toward visualizing structural dynamics in polyatomic molecules by strong-field-induced Coulomb explosion imaging.

Inter-cluster competition and resource partitioning may govern the ecology of Frankia

Microbes live in a complex communal ecosystem. The structural complexity of microbial community reflects diversity, functionality, as well as habitat type. Delineation of ecologically important microbial populations along with exploration of their roles in environmental adaptation or host-microbe interaction has a crucial role in modern microbiology. In this scenario, reverse ecology (the use of genomics to study ecology) plays a pivotal role. Since the co-existence of two different genera in one small niche should maintain a strict direct interaction, it will be interesting to utilize the concept of reverse ecology in this scenario. Here, we exploited an 'R' package, the RevEcoR, to resolve the issue of co-existing microbes which are proven to be a crucial tool for identifying the nature of their relationship (competition or complementation) persisting among them. Our target organism here is Frankia, a nitrogen-fixing actinobacterium popular for its genetic and host-specific nature. According to their plant host, Frankia has already been sub-divided into four clusters C-I, C-II, C-III, and C-IV. Our results revealed a strong competing nature of CI Frankia. Among the clusters of Frankia studied, the competition index between C-I and C-III was the largest. The other interesting result was the co-occurrence of C-II and C-IV groups. It was revealed that these two groups follow the theory of resource partitioning in their lifestyle. Metabolic analysis along with their differential transporter machinery validated our hypothesis of resource partitioning among C-II and C-IV groups.

Two- and three-body fragmentation of multiply charged tribromomethane by ultrafast laser pulses

This article provides mechanistic insight into the two- and three-body fragmentation dynamics of CHBr3 after strong-field ionization and discusses the possible isomerization of CHBr3 to BrCHBr–Br (iso-CHBr3) prior to the fragmentation.

Fully automated global longitudinal strain assessment using artificial intelligence developed and validated by a UK-wide echocardiography expert collaborative

Background

Left ventricular longitudinal strain has been reported to deliver reproducibility, sensitivity and prognostic value over and above ejection fraction. However, it currently relies on uninspectable proprietary algorithms and suffers from a lack of widespread clinical use. Uptake may be improved by increasing user trust through greater transparency.

Purpose

We therefore developed a machine-learning based method, trained, and validated with accredited experts from our AI Echocardiography Collaborative. We make the dataset, code, and trained network freely available under an open-source license.

Methods

AI enables strain to be calculated without relying on speckle tracking by directly locating key points and borders across frames. Strain can then be calculated as the fractional shortening of the left ventricular perimeter. We first curated a dataset of 7523 images, including 2587 apical four chamber, each labelled by a single expert from our collaboration of 17 hospitals, using our online platform (Figure 1). Using both this dataset and a semi-supervised approach, we trained a 3d convolutional neural network to identify the annulus, apex, and the endocardial border throughout the cardiac cycle.

Separately, we constructed an external validation dataset of 100 apical 4 chamber video-loops. The systolic and diastolic frame were identified, and each image was separately labelled by 11 experts. From these labels we then derived the expert consensus strain for each of the 100 video loops. These experts also ordered all 100 echocardiograms by their visual grading of left ventricular longitudinal function. Finally, a single expert calculated strain using two different proprietary commercial packages (A and B).

Results

Consensus strain measurements (obtained by averaging individual assessments by the 11 experts) across the 100 cases ranged from −4% to −27%, with strong correlations with the individual experts and machine methods (Figure 2). Using each cases' consensus across experts as the gold standard, median error from consensus was 3.1% for individual experts, 3.4% for Propriety A, 2.6% for Proprietary B, 2.6% for our AI.

Using the visual grading of longitudinal strain as the reference, the 11 individual experts and 4 machine methods each showed significant correlation: coefficients ranged from 0.55 to 0.69 for experts, and for Proprietary A was 0.68, Proprietary B 0.69, and our AI 0.69.

Conclusions

Our open-source, vendor-independent AI-based strain measure automatically produces values that agree with expert consensus, as strongly as the individual experts do. It also agrees with the subjective visual ranking by longitudinal function. Our open-source AI strain performs at least as well as closed-source speckle-based approaches, and may enable increased clinical and research use of longitudinal strain.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): NIHR Imperial BRC ITMAT.Dr Howard was additionally funded by Wellcome. Figure 1. Collaborative online platformFigure 2. Correlations between strain methods

Time-Resolved Pair-Correlated Imaging of the Photodissociation of Acetaldehyde at 267 nm: Pathway Partitioning

Photodissociation of acetaldehyde (CH₃CHO) by UV excitation involves interwoven multiple reaction pathways, including nonradiative decay, isomerization, transition-state pathway, roaming, and other dissociation mechanisms. Recently, we employed picosecond time-resolved, pair-correlated product imaging in a study of acetaldehyde photodissociation at 267 nm to disentangle those competing mechanisms and to elucidate the possible roaming pathways (Yang, C. H.; Chem. Sci. 2020, 11, 6423-6430). Here, we complement the pair-correlated product speed distribution of CO(v = 0) at the high-j side of the CO rotational state distribution in the CO + CH₄ channel and detail the two-dimensional data analysis of the time-resolved images. As a result, extensive comparisons with other studies can be made and the branching fractions of the previously assigned TS_cc(S₀), non-TS_cc(S₀), and CI(S₁/S₀) pathways for the CO(v = 0) + CH₄ molecular channel are evaluated to be 0.74 ± 0.08, 0.15 ± 0.02, and 0.11 ± 0.02, respectively. Together with the macroscopic branching ratio between the molecular (CO + CH₄) and radical (CH₃ + HCO) channels at 267 nm from the literature, a global view of the microscopic pathways can then be delineated, which provides invaluable insights and should pave the way for further studies of this interesting system.

18F-FDGPET/CT improves diagnostic certainty over the modified Duke Criteria in blood culture negative infective endocarditis

Funding Acknowledgements

Type of funding sources: None.

Introduction

Diagnosis of blood culture negative infective endocarditis (BCNIE) is challenging, with positive microbiology key in the modified Duke Criteria (mDC). ESC IE Guidelines (2015) recommend the use of 18F-FDG PET/CT (PET) in cases where transoesophageal echocardiography (TOE) is equivocal and where cardiac implantable device-related IE (CIDRE) is suspected. We explored the role of PET to improve diagnostic certainty in the challenging cohort of BCNIE.

Methods

Retrospective review of all suspected BCNIE patients undergoing PET (10/2015 to 01/2021). Myocardial suppression technique was used in all cases, and studies were assessed for valve/device avidity. Patients were classified as definite/possible/rejected IE by mDC pre- and post-PET, with incremental benefit assessed by net reclassification index (NRI) versus actual diagnosis. Actual diagnosis was defined by Endocarditis Team consensus or surgical specimen (where available) at a minimum of 2-months following index admission.

Results

PET was performed in 110/807 (13.6%) cases overall. BCNIE prevalence was 18% across the total cohort, with 25/110 (22.7%) PET studies in BCNIE patients (male = 17, mean age 65). (p = 0.16 for PET in BCNIE compared to overall). PET was undertaken in 8 CIDRE, 9 native IE (NVE) and 10 prosthetic IE (PVE); 2-patients had suspected CIDRE + PVE. TOE was performed in all cases, and surgery was required in 8/25 patients. IE was confirmed in 44% of cases.

PET sensitivity, specificity, positive and negative predictive values were 73%, 93%, 89% and 81%, respectively. Addition of PET to the mDC improved re-classification to definite or rejected IE, with NRI 0.633 (positive NRI 0.3; negative 0.333), and added weight to the original mDC classification in 14/25 (56%) of cases.

Conclusion

PET improves diagnostic certainty when combined with mDC in the evaluation of patients with BCNIE across NVE, PVE and CIDRE.

A simplified model for gel electrophoresis of a hydrophobic rigid colloid

Electrophoresis of a charged dielectric hydrophobic colloid embedded in a charged hydrogel medium is addressed. A slip velocity condition at the particle surface is considered. The characteristic of the gel electrophoresis is different compared with the free-solution electrophoresis due to the presence of immobile charges of the gel medium, which induces a strong background electroosmotic flow and modifies the Debye layer of the colloid. The gel electrophoresis of the dielectric hydrophobic charged colloid is made based on first-order perturbation analysis. A closed form solution involving simple exponential integrals for the mobility is derived, which reduces to several existing mobility expressions under limiting conditions such as for the gel electrophoresis of hydrophilic particles and a hydrophobic colloid in free-solution electrophoresis. We find that the mobility reversal is achieved by varying the Debye length or gel permeability. For the present first-order perturbation analysis, unlike free-solution electrophoresis, the particle dielectric permittivity is found to influence the mobility. One of the intriguing features of the present study is the derivation of the simplified mobility expression, which can be easily computed for a given set of parameter values.

Strong-field induced fragmentation and isomerization of toluene probed by ultrafast femtosecond electron diffraction and mass spectrometry

We investigate the fragmentation and isomerization of toluene molecules induced by strong-field ionization with a femtosecond near-infrared laser pulse. Momentum-resolved coincidence time-of-flight ion mass spectrometry is used to determine the relative yield of different ionic products and fragmentation channels as a function of laser intensity. Ultrafast electron diffraction is used to capture the structure of the ions formed on a picosecond time scale by comparing the diffraction signal with theoretical predictions. Through the combination of the two measurements and theory, we are able to determine the main fragmentation channels and to distinguish between ions with identical mass but different structures. In addition, our diffraction measurements show that the independent atom model, which is widely used to analyze electron diffraction patterns, is not a good approximation for diffraction from ions. We show that the diffraction data is in very good agreement with ab initio scattering calculations.

THREE-POINT AREA METHOD FOR THERMOLUMINESCENCE GLOW CURVE ANALYSIS AND ITS APPLICATION TO THE GLOW PEAK OF K2SRP2O7:PR

A method has been proposed to evaluate the kinetic parameters, viz. activation energy ($E$) and order of kinetics ($b$) from a single or isolated thermoluminescence (TL) glow peak. Along with the area under the entire curve, this method uses a set of three arbitrary data points and calculates the partial area under the curve from each point to the endpoint. In this way, the entire information associated with the curve is used and the method is named as 'Three-Point Area' (TPA) method. We have applied it successfully on a number of theoretically simulated TL curves generated in One Trap One Recombination centre (OTOR) model and General-Order Kinetics (GOK) model under quasi-equilibrium approximations with linear heating scheme. The activation energies are found in good agreement with input values for both the models. For OTOR model, temperature average of order of kinetics is estimated to compare with the present result. Systematic analysis is carried out for estimation of errors inherent in the method in the purview of GOK model. A closer look on the results reveals that any set of three points, preferably chosen from the rising side of the curve, can yield activation energy and order of kinetics. The validity of the method to extract $E$ and $b$ from experimental glow curves is exemplified by considering experimental TL data reported in literature. Finally, a complete study starting from the synthesis of a new phosphor $\mathrm{K_2SrP_2O_7:Pr} $ and analysis of the recorded TL data to estimate $E$ and $b$ employing the TPA method has been reported.

O-H stretching frequency red shifts do not correlate with the dissociation energies in the dimethylether and dimethylsulfide complexes of phenol derivatives

In this perspective, we present a comprehensive report on the spectroscopic and computational investigations of the hydrogen bonded (H-bonded) complexes of Me2O and Me2S with seven para-substituted H-bond donor phenols. The salient finding was that although the dissociation energies, D0, of the Me2O complexes were consistently higher than those of the analogous Me2S complexes, the red-shifts in phenolic O-H frequencies, Δν(O-H), showed the exactly opposite trend. This is in contravention of the general perception that the red shift in the X-H stretching frequency in the X-HY hydrogen bonded complexes is a reliable indicator of H-bond strength (D0), a concept popularly known as the Badger-Bauer rule. This is also in contrast to the trend reported for the H-bonded complexes of H2S/H2O with several para substituted phenols of different pKa values wherein the oxygen centered hydrogen bonded (OCHB) complexes consistently showed higher Δν(O-H) and D0 compared to those of the analogous sulfur centered hydrogen bonded (SCHB) complexes. Our effort was to understand these intriguing observations based on the spectroscopic investigations of 1 : 1 complexes in combination with a variety of high level quantum chemical calculations. Ab initio calculations at the MP2 level and the DFT calculations using various dispersion corrected density functionals (including DFT-D3) were performed on counterpoise corrected surfaces to compute the dissociation energy, D0, of the H-bonded complexes. The importance of anharmonic frequency computations is underscored as they were able to correctly reproduce the observed trend in the relative OH frequency shifts unlike the harmonic frequency computations. We have attempted to find a unified correlation that would globally fit the observed red shifts in the O-H frequency with the H-bonding strength for the four bases, namely, H2S, H2O, Me2O, and Me2S, in this set of H-bond donors. It was found that the proton affinity normalized Δν(O-H) values scale very well with the H-bond strength.

Mapping social reward and punishment processing in the human brain: A voxel-based meta-analysis of neuroimaging findings using the social incentive delay task

Social rewards or punishments motivate human learning and behaviour, and alterations in the brain circuits involved in the processing of these stimuli have been linked with several neuropsychiatric disorders. However, questions still remain about the exact neural substrates implicated in social reward and punishment processing. Here, we conducted four Anisotropic Effect Size Signed Differential Mapping voxel-based meta-analyses of fMRI studies investigating the neural correlates of the anticipation and receipt of social rewards and punishments using the Social Incentive Delay task. We found that the anticipation of both social rewards and social punishment avoidance recruits a wide network of areas including the basal ganglia, the midbrain, the dorsal anterior cingulate cortex, the supplementary motor area, the anterior insula, the occipital gyrus and other frontal, temporal, parietal and cerebellar regions not captured in previous coordinate-based meta-analysis. We identified decreases in the BOLD signal during the anticipation of both social reward and punishment avoidance in regions of the default-mode network that were missed in individual studies likely due to a lack of power. Receipt of social rewards engaged a robust network of brain regions including the ventromedial frontal and orbitofrontal cortices, the anterior cingulate cortex, the amygdala, the hippocampus, the occipital cortex and the brainstem, but not the basal ganglia. Receipt of social punishments increased the BOLD signal in the orbitofrontal cortex, superior and inferior frontal gyri, lateral occipital cortex and the insula. In contrast to the receipt of social rewards, we also observed a decrease in the BOLD signal in the basal ganglia in response to the receipt of social punishments. Our results provide a better understanding of the brain circuitry involved in the processing of social rewards and punishment. Furthermore, they can inform hypotheses regarding brain areas where disruption in activity may be associated with dysfunctional social incentive processing during disease.

Differentiating and Quantifying Gas-Phase Conformational Isomers Using Coulomb Explosion Imaging

Conformational isomerism plays a crucial role in defining the physical and chemical properties and biological activity of molecules ranging from simple organic compounds to complex biopolymers. However, it is often a significant challenge to differentiate and separate these isomers experimentally as they can easily interconvert due to their low rotational energy barrier. Here, we use the momentum correlation of fragment ions produced after inner-shell photoionization to distinguish conformational isomers of 1,2-dibromoethane (C₂H₄Br₂). We demonstrate that the three-body breakup channel, C₂H₄⁺ + Br⁺ + Br⁺, contains signatures of both sequential and concerted breakup, which are decoupled to distinguish the geometries of two conformational isomers and to quantify their relative abundance. The sensitivity of our method to quantify these yields is established by measuring the relative abundance change with sample temperature, which agrees well with calculations. Our study paves the way for using Coulomb explosion imaging to track subtle molecular structural changes.

The influence of risk factors on the onset and outcome of psychosis: What we learned from the GAP study

The GAP multidisciplinary study carried out in South London, recruited 410 first episode of psychosis patients and 370 controls; the aim was to elucidate the multiple genetic and environmental factors influencing the onset and outcome of psychosis. The study demonstrated the risk increasing effect of adversity in childhood (especially parental loss, abuse, and bullying) on onset of psychosis especially positive symptoms. Adverse life events more proximal to onset, being from an ethnic minority, and cannabis use also played important roles; indeed, one quarter of new cases of psychosis could be attributed to use of high potency cannabis. The "jumping to conclusions" bias appeared to mediate the effect of lower IQ on vulnerability to psychosis. We confirmed that environmental factors operate on the background of polygenic risk, and that genetic and environment act together to push individuals over the threshold for manifesting the clinical disorder. The study demonstrated how biological pathways involved in the stress response (HPA axis and immune system) provide important mechanisms linking social risk factors to the development of psychotic symptoms. Further evidence implicating an immune/inflammatory component to psychosis came from our finding of complement dysregulation in FEP. Patients also showed an upregulation of the antimicrobial alpha-defensins, as well as differences in expression patterns of genes involved in NF-κB signaling and Cytokine Production. Being of African origin not only increased risk of onset but also of a more difficult course of illness. The malign effect of childhood adversity predicted a poorer outcome as did continued use of high potency cannabis.

Impact of ion-steric and ion-partitioning effects on electrophoresis of soft particles

A theoretical study on the electrophoresis of a soft particle is made by taking into account the ion steric interactions and ion partitioning effects under a thin Debye layer consideration with negligible surface conduction. Objective of this study is to provide a simple expression for the mobility of a soft particle which accounts for the finite-ion-size effect and the ion partitioning arise due to the Born energy difference between two media. The Donnan potential in the soft layer is determined by considering the ion steric interactions and the ion partitioning effect. The volume exclusion due to the finite ion size is considered by the Carnahan-Starling equation and the ion partitioning is accounted through the difference in Born energy. The modified Poisson-Boltzmann equation coupled with Stokes-Darcy-Brinkman equations are considered to determine the mobility. A closed-form expression for the electrophoretic mobility is obtained, which reduces to several existing expressions for mobility under various limiting cases.

Chlorogenic Acid Enriched Green Coffee Ameliorated Renal Injury in Rats

The incidence of acute kidney injury (AKI) during the treatment with gentamicin (GM) is very common in hospitalized patients. Green coffee bean, containing chlorogenic acid (CGA) has been reported to improve non communicable diseases. In the present study, CGA enriched fraction of green coffee bean was evaluated on GM induced nephrotoxicity in rats. It was a preclinical case-controlled experimental intervention conducted in the Department of Pharmacology, R G Kar Medical College, Kolkata, India from 2016-2019 using animal model. CGA content of green coffee bean extract (GCBE) was isolated and quantified by high performance thin layer chromatography (HPTLC) (6.426%). The rats were treated with GCBE at the dose of 100, 200 and 400mg/kg in gentamicin (GM) induced AKI for five consecutive days. At day 6, the renal function was assessed through analysing urine, blood and renal tissues. GCBE dose dependently and significantly (p<0.001) lowered blood urea, creatinine and potassium while, enhanced sodium compared to AKI control. Moreover, it showed significant elevation in glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) and reduction in lipid peroxides (p<0.001). It was suggested that chlorogenic acid of green coffee seed can protect kidney through down regulation of p53 transcription factor and thereby attenuation of oxidative stress, inflammation and apoptotic process in renal tubules.

First Observation of Multiple Transverse Wobbling Bands of Different Kinds in ^{183}Au

We report the first observation of two wobbling bands in ^{183}Au, both of which were interpreted as the transverse wobbling (TW) band but with different behavior of their wobbling energies as a function of spin. It increases (decreases) with spin for the positive (negative) parity configuration. The crucial evidence for the wobbling nature of the bands, dominance of the E2 component in the ΔI=1 transitions between the partner bands, is provided by the simultaneous measurements of directional correlation from the oriented states ratio and the linear polarization of the γ rays. Particle rotor model calculations with triaxial deformation reproduce the experimental data well. A value of spin, I_{m}, has been determined for the observed TW bands below which the wobbling energy increases and above which it decreases with spin. The nucleus ^{183}Au is, so far, the only nucleus in which both the increasing and the decreasing parts are observed and thus gives the experimental evidence of the complete transverse wobbling phenomenon.

COMPARATIVE ANALYSIS OF CARBOXYMETHYL CELLULOSE AND PARTIALLY HYDROLYZED POLYACRYLAMIDE – LOW-SOLID NONDISPERSED DRILLING MUD WITH RESPECT TO PROPER-TY ENHANCEMENT AND SHALE INHIBITION

During drilling, different problems are encountered that can interfere with smooth drilling processes, including the accumulation of cuttings, reduced penetration rates, pipe sticking, loss of wellbore stability, and loss of circulation. These problems are generally encountered with conventional drilling mud, such as the bentonite–barite mud system. Formation damage is the most common problem encountered in bentonite mud systems with high solid content. In this work, we aimed to formulate two low-solid nondispersed (LSND) muds: carboxymethyl cellulose (CMC)–LSND mud and partially hydrolyzed polyacrylamide (PHPA)–LSND mud. A comparative analysis was performed to evaluate their property enhancements. LSND muds aid in maintaining hole stability and proper cutting removal. The results of this work show that the addition of both CMC and PHPA helps to improve drilling fluid properties; however, the PHPA–LSND mud was found to be superior. Shale swelling is a major concern in the petroleum industry, as it causes various other problems, such as pipe sticking, low penetration rates, and bit wear. The effect of these two LSND polymer muds in inhibiting shale swelling was analyzed using shale collected from the Champhai district of Mizoram, India.

Childhood trauma and being at-risk for psychosis are associated with higher peripheral endocannabinoids

BACKGROUND

Evidence has been accumulating regarding alterations in components of the endocannabinoid system in patients with psychosis. Of all the putative risk factors associated with psychosis, being at clinical high-risk for psychosis (CHR) has the strongest association with the onset of psychosis, and exposure to childhood trauma has been linked to an increased risk of development of psychotic disorder. We aimed to investigate whether being at-risk for psychosis and exposure to childhood trauma were associated with altered endocannabinoid levels.

METHOD

We compared 33 CHR participants with 58 healthy controls (HC) and collected information about previous exposure to childhood trauma as well as plasma samples to analyse endocannabinoid levels.

RESULTS

Individuals with both CHR and experience of childhood trauma had higher N-palmitoylethanolamine (p < 0.001) and anandamide (p < 0.001) levels in peripheral blood compared to HC and those with no childhood trauma. There was also a significant correlation between N-palmitoylethanolamine levels and symptoms as well as childhood trauma.

CONCLUSIONS

Our results suggest an association between CHR and/or childhood maltreatment and elevated endocannabinoid levels in peripheral blood, with a greater alteration in those with both CHR status and history of childhood maltreatment compared to those with either of those risks alone. Furthermore, endocannabinoid levels increased linearly with the number of risk factors and elevated endocannabinoid levels correlated with the severity of CHR symptoms and extent of childhood maltreatment. Further studies in larger cohorts, employing longitudinal designs are needed to confirm these findings and delineate the precise role of endocannabinoid alterations in the pathophysiology of psychosis.

Dual local drug delivery of vancomycin and farnesol for mitigation of MRSA infection in vivo - a pilot study

Surgical site infections after orthopaedic surgery using fracture fixation devices or endosseous implants create major surgical challenges with severe adverse effects, such as osteomyelitis. These infections are frequently caused by Staphylococcus aureus, often with high resistance to antibiotics, such as methicillin-resistant Staphylococcus aureus (MRSA). Due to the formation of impenetrable biofilms on implant surfaces, systemic antibiotic treatment has become exceedingly difficult. New solutions are pursued by combining several drugs using a controlled delivery system from specifically engineered implant surfaces. A sol-gel coating on titanium implants was previously developed with 20 wt % vancomycin and 30 wt % farnesol, with suppression of MRSA in vitro. The present study investigated the efficacy of sol-gel film coatings for controlled dual local delivery over 4 weeks utilising a rat infection model. The findings confirmed the viability of this new concept in vivo based on the differences observed between coatings containing vancomycin alone (SGV) and the dual-drug-containing coating with vancomycin and farnesol (SGVF). While both the SGVF and SGV coatings facilitated excellent preservation of the osseous microarchitecture, SGVF coating displayed a slightly higher potency for suppressing MRSA infiltration than SGV, in combination with a lower reactive bone remodelling activity, most likely by disturbing biofilm formation. The next step for advancing the concept of dual-drug delivery from sol-gel coatings to the clinic and confirming the promising effect of the SGVF coatings on reactive bone remodelling and suppressing MRSA infiltration is a study in a larger animal species with longer time points.

Clear evidence for element partitioning effects in a Ti-6Al-4V alloy by the first-principles phase field method

Ti-6 wt% Al-4 wt% V (Ti64) is an α + β titanium alloy, in which the alloying components strongly affect the mechanical properties. In this report, element partitioning effects in Ti64 are investigated by using the first-principles phase field (FPPF) method, which has recently been proposed by our group. In the FPPF method, the local free energy is calculated using a cluster expansion method in combination with density functional theory and the temperature effect is incorporated using potential renormalization theory. We have succeeded in identifying enrichment of Al (V) in the α (β) phase, i.e., the clear evidence for the element partitioning effects of Al and V, without using any thermodynamical parameter. The transformation of the β phase and the α phase in microstructure is investigated by varying the V and Al concentrations by a small amount. Our results are in excellent agreement with the recent experimental results, showing the validity of the FPPF method for ternary alloys.

Real-time tracking of the entangled pathways in the multichannel photodissociation of acetaldehyde

The roaming mechanism, an unconventional reaction path, was discovered more than a decade ago in the studies of formaldehyde photodissociation, H₂CO → H₂ + CO. Since then, observations of roaming have been claimed in numerous photochemical processes. A closer examination of the presented data, however, revealed that evidence for roaming is not always unequivocal, and some of the conclusions could be misleading. We report here an in-depth, joint experimental and theoretical study of the title reaction. By tracking the time-evolution of the pair-correlated product state distributions, we decipher the competing, interwoven reaction pathways that lead to the radical (CH₃ + HCO) and molecular (CH₄ + CO) products. Possible roaming pathways are then elucidated and a more precise descriptor of the phenomenon is delineated.

Exploring the structure of Xe isotopes in A ~ 130 region: Single particle and collective excitations

High and medium spin structures of 130,131Xe have been studied using α-induced fusion-evaporation reaction and the Indian National Gamma Array (INGA) coupled with a digital data acquisition system. Various new band structures and near yrast levels of 131Xe have been established. The multipolarities of the observed transitions have been assigned on the basis of the DCO ratios and the polarization asymmetry measurements. Band structures based on 1-quasi-particle (qp), 3-qp configurations have been observed. A new Magnetic Rotational (MR) band based on 5-qp configuration has also been established in 131Xe. The MR band has been interpreted in terms of shears mechanism with principal axis cranking (SPAC) calculations. Shell Model calculations are carried out to describe the non yrast states of 131Xe above the 11/2− isomer. New excited states have also been identified in 130Xe, produced in the same reaction.

Effects of short-term cannabidiol treatment on response to social stress in subjects at clinical high risk of developing psychosis

RATIONALE

Stress is a risk factor for psychosis and treatments which mitigate its harmful effects are needed. Cannabidiol (CBD) has antipsychotic and anxiolytic effects.

OBJECTIVES

We investigated whether CBD would normalise the neuroendocrine and anxiety responses to stress in clinical high risk for psychosis (CHR) patients.

METHODS

Thirty-two CHR patients and 26 healthy controls (HC) took part in the Trier Social Stress Test (TSST) and their serum cortisol, anxiety and stress associated with public speaking were estimated. Half of the CHR participants were on 600 mg/day of CBD (CHR-CBD) and half were on placebo (CHR-P) for 1 week.

RESULTS

One-way analysis of variance (ANOVA) revealed a significant effect of group (HC, CHR-P, CHR-CBD (p = .005) on cortisol reactivity as well as a significant (p = .003) linear decrease. The change in cortisol associated with experimental stress exposure was greatest in HC controls and least in CHR-P patients, with CHR-CBD patients exhibiting an intermediate response. Planned contrasts revealed that the cortisol reactivity was significantly different in HC compared with CHR-P (p = .003), and in HC compared with CHR-CBD (p = .014), but was not different between CHR-P and CHR-CBD (p = .70). Across the participant groups (CHR-P, CHR-CBD and HC), changes in anxiety and experience of public speaking stress (all p's < .02) were greatest in the CHR-P and least in the HC, with CHR-CBD participants demonstrating an intermediate level of change.

CONCLUSIONS

Our findings show that it is worthwhile to design further well powered studies which investigate whether CBD may be used to affect cortisol response in clinical high risk for psychosis patients and any effect this may have on symptoms.

Determination of Retinyl Palmitate (Vitamin A) in Fortified Fluid Milk by Liquid Chromatography: Collaborative Study

A liquid chromatographic (LC) method was developed for fast and simple measurement of retinyl palmitate (vitamin A) in fortified milk. Retinyl acetate internal standard was added to a test portion of milk followed by extraction into hexane. The hexane extract was analyzed by LC using a normal-phase silica gel column equilibrated with mobile phase (conditioned hexane–isopropanol, 99.85 + 0.15, v/v) about 1 h before injections. The retinyl palmitate concentration was calculated by using a relative response factor determined with calibration standards. In the collaborative study, 11 laboratories analyzed 13 pairs of fluid milk materials in blind duplicate. Twelve of the materials were composed of skim milk (&lt;0.5% fat), 1% fat milk, 2% fat milk, and 1% fat chocolate milk. Each material was fortified at 3 concentrations of retinyl palmitate of approximately 581 μg/L (1000 IU/qt), 1163 μg/L (2000 IU/qt), and 2236 μg/L (4000 IU/qt). The 13th material, unfortified skim milk, served as a matrix blank. Repeatability standard deviations (RSDr) without outliers ranged from 1.5 to 5.7% and reproducibility standard deviations (RSDR) without outliers ranged from 5.0 to 22.7%. cis-Isomers co-eluted with the predominant trans-retinyl palmitate isomer and were included in the results reported by all the collaborative laboratories. Endogenous long-chain esters from milk fat were also measured with the retinyl palmitate additive. The Study Director recommends that this method for determination of retinyl palmitate in fluid milk by LC be adopted First Action.

Spinal cord syndromes in patients with systemic lupus erythematosus: differentiating lupus myelitis, neuromyelitis optica, and multiple sclerosis

OBJECTIVE

Non-infectious myelitis in systemic lupus erythematosus (SLE) may be due to SLE myelitis, comorbid multiple sclerosis (MS), or neuromyelitis optica (NMO). We compared characteristics of these three conditions in SLE patients at a large academic institution.

METHODS

We searched for neurologic diagnoses of SLE myelitis, NMO myelitis, and MS myelitis among 2297 patients with at least four 1997 American College of Rheumatology revised criteria for SLE between 2000 and 2015. Each subject was reviewed by a neurologist to confirm the underlying neurologic diagnosis. Demographic, clinical, laboratory, and radiographic data were extracted and compared using Fisher's exact test, analysis of variance, and Wilcoxon rank-sum test.

RESULTS

Fifteen of the 2297 subjects with SLE (0.7%) met criteria for a spinal cord syndrome: seven had SLE myelitis, three had AQP4 seropositive NMO, and five had MS. The median SLE Disease Activity Index 2000 score at time of neurologic syndrome presentation was higher in SLE myelitis subjects (8, interquartile range (IQR) 7-16) compared with subjects with NMO (6, IQR 0-14) or MS (2, IQR 0-4), p = 0.02. Subjects with SLE myelitis were also more likely to have elevated anti-dsDNA antibodies at presentation (86%) compared with subjects with NMO (33%) or MS (0%), p = 0.03.

CONCLUSION

Myelitis occurs rarely among patients with SLE. Compared with subjects with SLE + NMO and subjects with SLE + MS, subjects with SLE myelitis had higher SLE disease activity at presentation.

P2764Medical management of Staphylococcus aureus infective endocarditis: unexpectedly favourable outcomes in an aggressive disease

Introduction

Early surgical intervention (ESI) for infective endocarditis (IE) is associated with improved outcomes. Staphylococcus aureus endocarditis (SAE) is associated with particularly high rates of tissue destruction, morbidity and mortality. However, the question as to whether ESI is mandated in all SAE continues to be debated, in both native (NVE) and prosthetic (PVE) endocarditis.

Methods

Retrospective review of all IE cases presenting to our institution from October 2015 to January 2019. IE was diagnosed following imaging and microbiological protocols as per ESC guidance, and data were extracted for those with SAE. Patients with isolated cardiac implantable electronic device IE or bacteraemia secondary to indwelling long-term venous catheter infection were excluded (non-valvular IE).

Results

Valvular IE was diagnosed in 411 patients overall; NVE in 286 (69.6%) and PVE in 125 (30.4%). S aureus was isolated in 111 patients (28.1%), of whom 5 had a Methicillin-resistant strain. SAE was confirmed in a similar proportion of NVE and PVE cases [83/111 (74.8%) and 28/111 (25.2%), respectively]. Surgical intervention was mandated in 35/83 with NVE (42.2%) and 11/28 (39.3%) with PVE, lower than in our overall cohort (55.9% and 48.8%, respectively).

In-hospital SAE mortality was 16.2% overall (18.4% medical vs 13.0% surgical), and contributes a significant proportion to overall mortality (29% to medical & 26% to surgical mortality). Figure 1 identifies the cause of death per mode of treatment, highlighting the aggressive nature of S aureus infection (abscess, disseminated infection and septic shock; n=8), the importance of advanced non-cardiac comorbidity precluding intervention (n=3) and ongoing intravenous drug use in those with PVE (n=4). However, medical management was successful in 57.8% (38/83) of NVE and 60.7% (17/28) of PVE cases, both in hospital and to a minimum follow-up of 3-months.

Conclusion

Staphylococcus aureus is virulent and highly pathogenic, driving severe sepsis and advanced tissue destruction in SAE. Despite this, medical management can be successful when following international guidance, but requires co-ordinated care driven by a multidisciplinary IE team at a cardiothoracic centre.

A numerical investigation of the heat transfer characteristics of water-based mango bark nanofluid flowing in a double-pipe heat exchanger

In this study, the heat transfer characteristics of a new class of nanofluids made from mango bark was numerically simulated and studied during turbulent flow through a double pipe heat exchanger. A range of volume fractions was considered for a particle size of 100 nm. A two-phase flow was considered using the mixture model. The mixture model governing equations of continuity, momentum, energy and volume fraction were solved using the finite-volume method. The results showed an increase of the Nusselt number by 68% for a Reynolds number of 5,000 and 45% for a Reynolds number of 13 000, and the heat transfer coefficient of the nanofluid was about twice that of the base fluid. In addition, the Nusselt number decreased by an average value of 0.76 with an increase of volume fraction by 1%. It was also found that there was a range of Reynolds numbers in which the trend of the average heat transfer coefficient of the nanofluid was completely reversed, and several plots showing zones of higher heat transfer which if taken advantage of in design will lead to higher heat transfer while avoiding other zones that have low heat transfer. It is hoped that these results will influence the thermal design of new heat exchangers.