First Application of Mass Measurements with the Rare-RI Ring Reveals the Solar r-Process Abundance Trend at A=122 and A=123.

The Rare-RI Ring (R3) is a recently commissioned cyclotronlike storage ring mass spectrometer dedicated to mass measurements of exotic nuclei far from stability at Radioactive Isotope Beam Factory (RIBF) in RIKEN. The first application of mass measurement using the R3 mass spectrometer at RIBF is reported. Rare isotopes produced at RIBF-^{127}Sn, ^{126}In, ^{125}Cd, ^{124}Ag, ^{123}Pd-were injected in R3. Masses of ^{126}In, ^{125}Cd, and ^{123}Pd were measured whereby the mass uncertainty of ^{123}Pd was improved. This is the first reported measurement with a new storage ring mass spectrometry technique realized at a heavy-ion cyclotron and employing individual injection of the preidentified rare nuclei. The latter is essential for the future mass measurements of the rarest isotopes produced at RIBF. The impact of the new ^{123}Pd result on the solar r-process abundances in a neutron star merger event is investigated by performing reaction network calculations of 20 trajectories with varying electron fraction Y_{e}. It is found that the neutron capture cross section on ^{123}Pd increases by a factor of 2.2 and ß-delayed neutron emission probability, P_{1 n}, of ^{123}Rh increases by 14%. The neutron capture cross section on ^{122}Pd decreases by a factor of 2.6 leading to pileup of material at A=122, thus reproducing the trend of the solar r-process abundances. The trend of the two-neutron separation energies (S_{2n}) was investigated for the Pd isotopic chain. The new mass measurement with improved uncertainty excludes large changes of the S_{2n} value at N=77. Such large increase of the S_{2n} values before N=82 was proposed as an alternative to the quenching of the N=82 shell gap to reproduce r-process abundances in the mass region of A=112-124.

Polyketide ß-branching: diversity, mechanism and selectivity.

Covering: 2008 to August 2020 Polyketides are a family of natural products constructed from simple building blocks to generate a diverse range of often complex chemical structures with biological activities of both pharmaceutical and agrochemical importance. Their biosynthesis is controlled by polyketide synthases (PKSs) which catalyse the condensation of thioesters to assemble a functionalised linear carbon chain. Alkyl-branches may be installed at the nucleophilic α- or electrophilic ß-carbon of the growing chain. Polyketide ß-branching is a fascinating biosynthetic modification that allows for the conversion of a ß-ketone into a ß-alkyl group or functionalised side-chain. The overall transformation is catalysed by a multi-protein 3-hydroxy-3-methylglutaryl synthase (HMGS) cassette and is reminiscent of the mevalonate pathway in terpene biosynthesis. The first step most commonly involves the aldol addition of acetate to the electrophilic carbon of the ß-ketothioester catalysed by a 3-hydroxy-3-methylglutaryl synthase (HMGS). Subsequent dehydration and decarboxylation selectively generates either α,ß- or ß,γ-unsaturated ß-alkyl branches which may be further modified. This review covers 2008 to August 2020 and summarises the diversity of ß-branch incorporation and the mechanistic details of each catalytic step. This is extended to discussion of polyketides containing multiple ß-branches and the selectivity exerted by the PKS to ensure ß-branching fidelity. Finally, the application of HMGS in data mining, additional ß-branching mechanisms and current knowledge of the role of ß-branches in this important class of biologically active natural products is discussed.

Time to consider the role of rationalisation in health psychology.

OBJECTIVE: The objective of this study was to determine the interaction between psychological factors, belief systems, and engagement around public health initiatives. STUDY DESIGN: We conducted a longitudinal observational study, utilising convenience sampling to examine illness-related perception in the immediate and medium-term stages of the first wave of the SARS-CoV-2 pandemic in the UK. METHODS: Weekly questionnaires assessed our primary measure, illness-related perception, using The Health Anxiety Inventory. Other psychological measures included apathy, loneliness, depersonalisation, state anxiety, trait anxiety as well as personality traits. Multiple regressions were performed to determine which psychological factors predicted the variance of health anxiety every week using the enter method. RESULTS: A combination of psychological variables that varied over time and were modulated by external events predicted the evolution of illness-related perception and associated aversion to perceived threat. CONCLUSION: Our findings highlight how in the face of a public health crisis, psychological factors play a determining role in the synthesis of beliefs as well as guiding human behaviour.

A Canadian cancer trials group phase IB study of durvalumab (anti-PD-L1) plus tremelimumab (anti-CTLA-4) given concurrently or sequentially in patients with advanced, incurable solid malignancies.

Background The IND.226 study was a phase Ib study to determine the recommended phase II dose of durvalumab + tremelimumab in combination with standard platinum-doublet chemotherapy. Sequential administration of multiple agents increases total chair time adding costs overall and inconvenience for patients. This cohort of the IND.226 study evaluated the safety and tolerability of durvalumab + tremelimumab given either sequentially (SEQ) or concurrently (CON). Methods Patients with advanced solid tumours were enrolled and randomised to either SEQ tremelimumab 75 mg IV over 1 h followed by durvalumab 1500 mg IV over 1 h q4wks on the same day, or CON administration over 1 h. The serum pharmacokinetic profile of SEQ versus CON of durvalumab and tremelimumab administration was also evaluated. Results 14 patients either received SEQ (n = 7pts) or CON (n = 7 pts). There were no infusion related reactions. Drug related adverse events (AEs) were mainly low grade and manageable, and comparable in frequency between SEQ/CON- fatigue (43%/57%), rash (43%/43%), pruritus (43%/29%) and nausea (14%/29%). One patient in each cohort discontinued treatment due to toxicity. The PK profiles of durvalumab and tremelimumab were similar between CON and SEQ, and to historical reference data. Conclusions Concurrent administration of durvalumab and tremelimumab over 1 h is safe with a comparable PK profile to sequential administration.

Properties of

Mass-separated ^{187}Ta_{114} in a high-spin isomeric state has been produced for the first time by multinucleon transfer reactions, employing an argon gas-stopping cell and laser ionization. Internal γ rays revealed a T_{1/2}=7.3±0.9 s isomer at 1778±1 keV, which decays through a rotational band with perturbations associated with the approach to a prolate-oblate shape transition. Model calculations show less influence from triaxiality compared to heavier elements in the same mass region. The isomer-decay reduced E2 hindrance factor f_{ν}=27±1 supports the interpretation that axial symmetry is approximately conserved.

Metastable States of

Here we present new information on the shape evolution of the very neutron-rich ^{92,94}Se nuclei from an isomer-decay spectroscopy experiment at the Radioactive Isotope Beam Factory at RIKEN. High-resolution germanium detectors were used to identify delayed γ rays emitted following the decay of their isomers. New transitions are reported extending the previously known level schemes. The isomeric levels are interpreted as originating from high-K quasineutron states with an oblate deformation of ß∼0.25, with the high-K state in ^{94}Se being metastable and K hindered. Following this, ^{94}Se is the lowest-mass neutron-rich nucleus known to date with such a substantial K hindrance. Furthermore, it is the first observation of an oblate K isomer in a deformed nucleus. This opens up the possibility for a new region of K isomers at low Z and at oblate deformation, involving the same neutron orbitals as the prolate orbitals within the classic Z∼72 deformed hafnium region. From an interpretation of the level scheme guided by theoretical calculations, an oblate deformation is also suggested for the ^{94}Se_{60} ground-state band.

Imaging post liver transplantation part I: vascular complications.

Liver transplantation continues to rise in frequency, with over 1,000 procedures performed in the UK in 2018. Complications are increasingly uncommon but when they occur, early recognition and intervention is vital to save grafts. Imaging after the perioperative period is often performed at patients' local hospitals meaning that all radiologists and sonographers need to have an understanding of how to assess a transplant liver. Part I of this series will focus on vascular complications, including the normal postoperative vascular anatomy following liver transplantation, normal post-transplantation vascular imaging findings and abnormal findings that may prompt further investigation. Vascular complications following liver transplantation will be illustrated using a collection of cases.

A Novel Human CAMK2A Mutation Disrupts Dendritic Morphology and Synaptic Transmission, and Causes ASD-Related Behaviors.

Characterizing the functional impact of novel mutations linked to autism spectrum disorder (ASD) provides a deeper mechanistic understanding of the underlying pathophysiological mechanisms. Here we show that a de novo Glu183 to Val (E183V) mutation in the CaMKIIα catalytic domain, identified in a proband diagnosed with ASD, decreases both CaMKIIα substrate phosphorylation and regulatory autophosphorylation, and that the mutated kinase acts in a dominant-negative manner to reduce CaMKIIα-WT autophosphorylation. The E183V mutation also reduces CaMKIIα binding to established ASD-linked proteins, such as Shank3 and subunits of l-type calcium channels and NMDA receptors, and increases CaMKIIα turnover in intact cells. In cultured neurons, the E183V mutation reduces CaMKIIα targeting to dendritic spines. Moreover, neuronal expression of CaMKIIα-E183V increases dendritic arborization and decreases both dendritic spine density and excitatory synaptic transmission. Mice with a knock-in CaMKIIα-E183V mutation have lower total forebrain CaMKIIα levels, with reduced targeting to synaptic subcellular fractions. The CaMKIIα-E183V mice also display aberrant behavioral phenotypes, including hyperactivity, social interaction deficits, and increased repetitive behaviors. Together, these data suggest that CaMKIIα plays a previously unappreciated role in ASD-related synaptic and behavioral phenotypes.SIGNIFICANCE STATEMENT Many autism spectrum disorder (ASD)-linked mutations disrupt the function of synaptic proteins, but no single gene accounts for >1% of total ASD cases. The molecular networks and mechanisms that couple the primary deficits caused by these individual mutations to core behavioral symptoms of ASD remain poorly understood. Here, we provide the first characterization of a mutation in the gene encoding CaMKIIα linked to a specific neuropsychiatric disorder. Our findings demonstrate that this ASD-linked de novo CAMK2A mutation disrupts multiple CaMKII functions, induces synaptic deficits, and causes ASD-related behavioral alterations, providing novel insights into the synaptic mechanisms contributing to ASD.

Transition from Propagating Polariton Solitons to a Standing Wave Condensate Induced by Interactions.

We explore phase transitions of polariton wave packets, first, to a soliton and then to a standing wave polariton condensate in a multimode microwire system, mediated by nonlinear polariton interactions. At low excitation density, we observe ballistic propagation of the multimode polariton wave packets arising from the interference between different transverse modes. With increasing excitation density, the wave packets transform into single-mode bright solitons due to effects of both intermodal and intramodal polariton-polariton scattering. Further increase of the excitation density increases thermalization speed, leading to relaxation of the polariton density from a solitonic spectrum distribution in momentum space down to low momenta, with the resultant formation of a nonequilibrium condensate manifested by a standing wave pattern across the whole sample.

Exciton Polaritons in a Two-Dimensional Lieb Lattice with Spin-Orbit Coupling.

We study exciton polaritons in a two-dimensional Lieb lattice of micropillars. The energy spectrum of the system features two flat bands formed from S and P_{x,y} photonic orbitals, into which we trigger bosonic condensation under high power excitation. The symmetry of the orbital wave functions combined with photonic spin-orbit coupling gives rise to emission patterns with pseudospin texture in the flat band condensates. Our Letter shows the potential of polariton lattices for emulating flat band Hamiltonians with spin-orbit coupling, orbital degrees of freedom, and interactions.

Mechanistic Insight into Palladium-Catalyzed Cycloisomerization: A Combined Experimental and Theoretical Study.

The cycloisomerization of enynes catalyzed by Pd(OAc)2 and bis-benzylidene ethylenediamine (bbeda) is a landmark methodology in transition-metal-catalyzed cycloisomerization. However, the mechanistic pathway by which this reaction proceeds has remained unclear for several decades. Here we describe mechanistic investigations into this reaction using enynamides, which deliver azacycles with high regio- and stereocontrol. Extensive 1H NMR spectroscopic studies and isotope effects support a palladium(II) hydride-mediated pathway and reveal crucial roles of bbeda, water, and the precise nature of the Pd(OAc)2 pre-catalyst. Computational studies support these mechanistic findings and lead to a clear picture of the origins of the high stereocontrol that can be achieved in this transformation, as well as suggesting a novel mechanism by which hydrometalation proceeds.

Dark Solitons in High Velocity Waveguide Polariton Fluids.

We study exciton-polariton nonlinear optical fluids in the high momentum waveguide regime for the first time. We demonstrate the formation of dark solitons with the expected dependence of width on fluid density for both main classes of soliton-forming fluid defects. The results are well described by numerical modeling of the fluid propagation. We deduce a continuous wave nonlinearity more than ten times that on picosecond time scales, arising due to interaction with the exciton reservoir.

Publisher's Note: Spin Textures of Exciton-Polaritons in a Tunable Microcavity with Large TE-TM Splitting [Phys. Rev. Lett. 115, 246401 (2015)].

This corrects the article DOI: 10.1103/PhysRevLett.115.246401.

94 ß-Decay Half-Lives of Neutron-Rich _{55}Cs to _{67}Ho: Experimental Feedback and Evaluation of the r-Process Rare-Earth Peak Formation.

The ß-decay half-lives of 94 neutron-rich nuclei ^{144-151}Cs, ^{146-154}Ba, ^{148-156}La, ^{150-158}Ce, ^{153-160}Pr, ^{156-162}Nd, ^{159-163}Pm, ^{160-166}Sm, ^{161-168}Eu, ^{165-170}Gd, ^{166-172}Tb, ^{169-173}Dy, ^{172-175}Ho, and two isomeric states ^{174m}Er, ^{172m}Dy were measured at the Radioactive Isotope Beam Factory, providing a new experimental basis to test theoretical models. Strikingly large drops of ß-decay half-lives are observed at neutron-number N=97 for _{58}Ce, _{59}Pr, _{60}Nd, and _{62}Sm, and N=105 for _{63}Eu, _{64}Gd, _{65}Tb, and _{66}Dy. Features in the data mirror the interplay between pairing effects and microscopic structure. r-process network calculations performed for a range of mass models and astrophysical conditions show that the 57 half-lives measured for the first time play an important role in shaping the abundance pattern of rare-earth elements in the solar system.

Review of metastable states in heavy nuclei.

The structure of nuclear isomeric states is reviewed in the context of their role in contemporary nuclear physics research. Emphasis is given to high-spin isomers in heavy nuclei, with [Formula: see text]. The possibility to exploit isomers to study some of the most exotic nuclei is a recurring theme. In spherical nuclei, the role of octupole collectivity is discussed in detail, while in deformed nuclei the limitations of the K quantum number are addressed. Isomer targets and isomer beams are considered, along with applications related to energy storage, astrophysics, medicine, and experimental advances.

Identification of a candidate biomarker from perfusion MRI to anticipate glioblastoma progression after chemoradiation.

OBJECTIVE: To identify relevant relative cerebral blood volume biomarkers from T2* dynamic-susceptibility contrast magnetic resonance imaging to anticipate glioblastoma progression after chemoradiation. METHODS: Twenty-five patients from a prospective study with glioblastoma, primarily treated by chemoradiation, were included. According to the last follow-up MRI confirmed status, patients were divided into: relapse group (n = 13) and control group (n = 12). The time of last MR acquisition was tend; MR acquisitions performed at tend-2M, tend-4M and tend-6M (respectively 2, 4 and 6 months before tend) were analyzed to extract relevant variations among eleven perfusion biomarkers (B). These variations were assessed through R(B), as the absolute value of the ratio between ∆B from tend-4M to tend-2M and ∆B from tend-6M to tend-4M. The optimal cut-off for R(B) was determined using receiver-operating-characteristic curve analysis. RESULTS: The fraction of hypoperfused tumor volume (F_hPg) was a relevant biomarker. A ratio R(F_hPg) ≥ 0.61 would have been able to anticipate relapse at the next follow-up with a sensitivity/specificity/accuracy of 92.3 %/63.6 %/79.2 %. High R(F_hPg) (≥0.61) was associated with more relapse at tend compared to low R(F_hPg) (75 % vs 12.5 %, p = 0.008). CONCLUSION: Iterative analysis of F_hPg from consecutive examinations could provide surrogate markers to predict progression at the next follow-up. KEY POINTS: • Related rCBV biomarkers from DSC were assessed to anticipate GBM progression. • Biomarkers were assessed through their patterns of variation during the follow-up. • The fraction of hypoperfused tumour volume (F_hP g ) seemed to be a relevant biomarker. • An innovative ratio R(F_hP g ) could be an early surrogate marker of relapse. • A significant time gain could be achieved in the management of GBM patients.

WSe2 Light-Emitting Tunneling Transistors with Enhanced Brightness at Room Temperature.

Monolayers of molybdenum and tungsten dichalcogenides are direct bandgap semiconductors, which makes them promising for optoelectronic applications. In particular, van der Waals heterostructures consisting of monolayers of MoS2 sandwiched between atomically thin hexagonal boron nitride (hBN) and graphene electrodes allows one to obtain light emitting quantum wells (LEQWs) with low-temperature external quantum efficiency (EQE) of 1%. However, the EQE of MoS2- and MoSe2-based LEQWs shows behavior common for many other materials: it decreases fast from cryogenic conditions to room temperature, undermining their practical applications. Here we compare MoSe2 and WSe2 LEQWs. We show that the EQE of WSe2 devices grows with temperature, with room temperature EQE reaching 5%, which is 250× more than the previous best performance of MoS2 and MoSe2 quantum wells in ambient conditions. We attribute such different temperature dependences to the inverted sign of spin-orbit splitting of conduction band states in tungsten and molybdenum dichalcogenides, which makes the lowest-energy exciton in WSe2 dark.

Seasonal migration of the starry smooth-hound shark Mustelus asterias as revealed from tag-recapture data of an angler-led tagging programme.

The primary aim of this long-term angler-led tagging programme was to gain information about seasonal changes in distribution of the starry smooth-hound shark Mustelus asterias, along the Dutch coast for management and conservation purposes. Between 2011 and 2014, M. asterias comprised 92·6% (n = 2418) of the total elasmobranch catch (n = 2612) by the licenced group of taggers within the Dutch Delta of which 2244 M. asterias were fin-tagged with plastic rototags. Sex and total length (LT ) composition inside the eastern tidal basin (Oosterschelde) were significantly different, i.e. more females and larger individuals, than outside indicating a pupping ground, which was confirmed by the capture of 30 newborn pups (≤32 cm). The distribution pattern of reported recaptured M. asterias (return-rate 3·6%, n = 80) showed a circannual migration between summering in the southern North Sea and wintering in the English Channel and the Bay of Biscay, and suggests that M. asterias is philopatric. The Dutch angling season for M. asterias runs from approximately mid-May to mid-October when the water temperature is above 13° C. Recaptures of eight mature females, but no males in the Bay of Biscay, indicate partial spatial segregation by sex, where mature females migrate over larger distances than immature females and males. These observations, with the absence of recaptures in other known summering areas (i.e. the Irish Sea and Bristol Channel), suggest that the southern North Sea is used by a separate population. Implications for management and recommendations to improve and expand the study approach are discussed.

Spin Textures of Exciton-Polaritons in a Tunable Microcavity with Large TE-TM Splitting.

We report an extended family of spin textures of zero-dimensional exciton-polaritons spatially confined in tunable open microcavity structures. The transverse-electric-transverse-magnetic (TE-TM) splitting, which is enhanced in the open cavity structures, leads to polariton eigenstates carrying quantized spin vortices. Depending on the strength and anisotropy of the cavity confining potential and of the TE-TM induced splitting, which can be tuned via the excitonic or photonic fractions, the exciton-polariton emissions exhibit either spin-vortex-like patterns or linear polarization, in good agreement with theoretical modeling.