bluuebunny/crossref_metadata_2025_split huggingface dataset:
Red light-driven electron sacrificial agents-free photoreduction of inert aryl halides via triplet-triplet annihilation
Authors: Zeng Le , Huang Ling , Lin Wenhai , Jiang Lin-Han , Han Gang 
Published: February 2023

AbstractSelective photoactivation of inert aryl halides is a fundamental challenge in organic synthesis. Specially, the long-wavelength red light is more desirable than the widely-applied blue light as the excitation source for photoredox catalysis, due to its superior penetration depth. However, the long-wavelength red light-driven photoactivation of inert aryl halides remains a challenge, mainly because of the low energy of the single long-wavelength red photon. Herein, we report the photoreduction of aryl bromides/chlorides with 656 nm LED via triplet-triplet annihilation (TTA) strategy. This method is based on our discovery that the commonly used chromophore of perylene can serve as an efficient and metal-free photocatalyst to enable the photoreduction of inert aryl halides without the conventional need for electronic sacrificial agents. By introducing a red light-absorbing photosensitizer to this perylene system, we accomplish the long-wavelength red light-driven photoreduction of aryl halides via sensitized TTA mechanism. Moreover, the performance of such a TTA-mediated photoreduction can be significantly enhanced when restricting the rotation freedom of phenyl moiety for perylene derivatives to suppress their triplet nonradiative transition, in both small and large-scale reaction settings.
Noncanonical electromechanical coupling paths in cardiac hERG potassium channel
Authors: Bassetto Carlos A. Z. , Costa Flavio , Guardiani Carlo , Bezanilla Francisco , Giacomello Alberto 
Published: February 2023

AbstractVoltage-gated potassium channels are involved in many physiological processes such as nerve impulse transmission, the heartbeat, and muscle contraction. However, for many of them the molecular determinants of the gating mechanism remain elusive. Here, using a combination of theoretical and experimental approaches, we address this problem focusing on the cardiac hERG potassium channel. Network analysis of molecular dynamics trajectories reveals the presence of a kinematic chain of residues that couples the voltage sensor domain to the pore domain and involves the S4/S1 and S1/S5 subunit interfaces. Mutagenesis experiments confirm the role of these residues and interfaces in the activation and inactivation mechanisms. Our findings demonstrate the presence of an electromechanical transduction path crucial for the non-domain-swapped hERG channel gating that resembles the noncanonical path identified in domain-swapped K+channels.
Polyfunctionalization of vicinal carbon centers and synthesis of unsymmetric 1,2,3,4-tetracarbonyl compounds
Authors: De Angelis Luca , Pei Chao , Narro Ana L. , Wherritt Daniel , Koenigs Rene M. , Doyle Michael P. 
Published: February 2023

AbstractThe synthesis and characterization of organic compounds with unusual atom or functional group connectivity is one of the main driving forces in the discovery of new synthetic methods that has raised the interest of chemists for many years. Polycarbonyl compounds are such compounds wherein multiple carbonyl groups are directly juxtaposed and influence each other’s chemical reactivity. While 1,2-dicarbonyl or 1,2,3-tricarbonyl compounds are well-known in organic chemistry, the 1,2,3,4-tetracarbonyl motif remains barely explored. Herein, we report on the synthesis of such 1,2,3,4-tetracarbonyl compounds employing a synthetic strategy that involves C-nitrosation of enoldiazoacetates, while the diazo functional group remains untouched. This strategy not only leverages the synthesis of 1,2,3,4-tetracarbonyl compounds to an unprecedented level, it also accomplishes the synthesis of 1,2,3,4-tetracarbonyl compounds, wherein each carbonyl group is orthogonally masked. Combined experimental and theoretical studies provide an understanding of the reaction mechanism and rationalize the formation of such 1,2,3,4-tetracarbonyl compounds.
Phenotypic characterization of single CD4+ T cells harboring genetically intact and inducible HIV genomes
Authors: Dufour Caroline , Richard Corentin , Pardons Marion , Massanella Marta , Ackaoui Antoine , Murrell Ben , Routy Bertrand , Thomas Réjean , Routy Jean-Pierre , Fromentin Rémi , Chomont Nicolas 
Published: February 2023

AbstractThe phenotype of the rare HIV-infected cells persisting during antiretroviral therapies (ART) remains elusive. We developed a single-cell approach that combines the phenotypic analysis of HIV-infected cells with near full-length sequencing of their associated proviruses to characterize the viral reservoir in 6 male individuals on suppressive ART. We show that individual cells carrying clonally expanded identical proviruses display very diverse phenotypes, indicating that cellular proliferation contributes to the phenotypic diversification of the HIV reservoir. Unlike most viral genomes persisting on ART, inducible and translation-competent proviruses rarely present large deletions but are enriched in defects in the Ψ locus. Interestingly, the few cells harboring genetically intact and inducible viral genomes express higher levels of the integrin VLA-4 compared to uninfected cells or cells with defective proviruses. Viral outgrowth assay confirmed that memory CD4+ T cells expressing high levels of VLA-4 are highly enriched in replication-competent HIV (27-fold enrichment). We conclude that although clonal expansions diversify the phenotype of HIV reservoir cells, CD4+ T cells harboring replication-competent HIV retain VLA-4 expression.
Room-temperature photosynthesis of propane from CO2 with Cu single atoms on vacancy-rich TiO2
Authors: Shen Yan , Ren Chunjin , Zheng Lirong , Xu Xiaoyong , Long Ran , Zhang Wenqing , Yang Yong , Zhang Yongcai , Yao Yingfang , Chi Haoqiang , Wang Jinlan , Shen Qing , Xiong Yujie , Zou Zhigang , Zhou Yong 
Published: February 2023

AbstractPhotochemical conversion of CO2 into high-value C2+ products is difficult to achieve due to the energetic and mechanistic challenges in forming multiple C-C bonds. Herein, an efficient photocatalyst for the conversion of CO2 into C3H8 is prepared by implanting Cu single atoms on Ti0.91O2 atomically-thin single layers. Cu single atoms promote the formation of neighbouring oxygen vacancies (VOs) in Ti0.91O2 matrix. These oxygen vacancies modulate the electronic coupling interaction between Cu atoms and adjacent Ti atoms to form a unique Cu-Ti-VO unit in Ti0.91O2 matrix. A high electron-based selectivity of 64.8% for C3H8 (product-based selectivity of 32.4%), and 86.2% for total C2+ hydrocarbons (product-based selectivity of 50.2%) are achieved. Theoretical calculations suggest that Cu-Ti-VO unit may stabilize the key *CHOCO and *CH2OCOCO intermediates and reduce their energy levels, tuning both C1-C1 and C1-C2 couplings into thermodynamically-favourable exothermal processes. Tandem catalysis mechanism and potential reaction pathway are tentatively proposed for C3H8 formation, involving an overall (20e− – 20H+) reduction and coupling of three CO2 molecules at room temperature.
Thermodynamics of diamond formation from hydrocarbon mixtures in planets
Authors: Cheng Bingqing , Hamel Sebastien , Bethkenhagen Mandy 
Published: February 2023

AbstractHydrocarbon mixtures are extremely abundant in the Universe, and diamond formation from them can play a crucial role in shaping the interior structure and evolution of planets. With first-principles accuracy, we first estimate the melting line of diamond, and then reveal the nature of chemical bonding in hydrocarbons at extreme conditions. We finally establish the pressure-temperature phase boundary where it is thermodynamically possible for diamond to form from hydrocarbon mixtures with different atomic fractions of carbon. Notably, here we show a depletion zone at pressures above 200 GPa and temperatures below 3000 K-3500 K where diamond formation is thermodynamically favorable regardless of the carbon atomic fraction, due to a phase separation mechanism. The cooler condition of the interior of Neptune compared to Uranus means that the former is much more likely to contain the depletion zone. Our findings can help explain the dichotomy of the two ice giants manifested by the low luminosity of Uranus, and lead to a better understanding of (exo-)planetary formation and evolution.
Metasurface-stabilized optical microcavities
Authors: Ossiander Marcus , Meretska Maryna Leonidivna , Rourke Sarah , Spägele Christina , Yin Xinghui , Benea-Chelmus Ileana-Cristina , Capasso Federico 
Published: February 2023

AbstractCavities concentrate light and enhance its interaction with matter. Confining to microscopic volumes is necessary for many applications but space constraints in such cavities limit the design freedom. Here we demonstrate stable optical microcavities by counteracting the phase evolution of the cavity modes using an amorphous Silicon metasurface as cavity end mirror. Careful design allows us to limit the metasurface scattering losses at telecom wavelengths to less than 2% and using a distributed Bragg reflector as metasurface substrate ensures high reflectivity. Our demonstration experimentally achieves telecom-wavelength microcavities with quality factors of up to 4600, spectral resonance linewidths below 0.4 nm, and mode volumes below $$2.7{\lambda }^{3}$$
2.7

λ

3

. The method introduces freedom to stabilize modes with arbitrary transverse intensity profiles and to design cavity-enhanced hologram modes. Our approach introduces the nanoscopic light control capabilities of dielectric metasurfaces to cavity electrodynamics and is industrially scalable using semiconductor manufacturing processes.
Using machine learning with optical profilometry for GaN wafer screening
Authors: Gallagher James C. , Mastro Michael A. , Ebrish Mona A. , Jacobs Alan G. , Gunning Brendan P. , Kaplar Robert J. , Hobart Karl D. , Anderson Travis J. 
Published: February 2023

AbstractTo improve the manufacturing process of GaN wafers, inexpensive wafer screening techniques are required to both provide feedback to the manufacturing process and prevent fabrication on low quality or defective wafers, thus reducing costs resulting from wasted processing effort. Many of the wafer scale characterization techniques—including optical profilometry—produce difficult to interpret results, while models using classical programming techniques require laborious translation of the human-generated data interpretation methodology. Alternatively, machine learning techniques are effective at producing such models if sufficient data is available. For this research project, we fabricated over 6000 vertical PiN GaN diodes across 10 wafers. Using low resolution wafer scale optical profilometry data taken before fabrication, we successfully trained four different machine learning models. All models predict device pass and fail with 70–75% accuracy, and the wafer yield can be predicted within 15% error on the majority of wafers.
Modulation of amygdala activity for emotional faces due to botulinum toxin type A injections that prevent frowning
Authors: Stark Shauna , Stark Craig , Wong Brian , Brin Mitchell F. 
Published: February 2023

AbstractAccording to the facial feedback hypothesis, when we see an angry or happy face, we contract or flex the relevant muscles to recreate the expression to assist in identifying and experiencing the emotion reflected. We investigated the facial feedback hypothesis by using botulinum toxin type A (onabotulinumtoxinA; onabotA) injections to induce temporary paralysis in the glabellar muscles (responsible for frowning) and measured functional brain activity during the processing of emotional faces. Ten females viewed pictures of happy and angry faces during two functional magnetic resonance imaging (fMRI) scan sessions: one prior (Pre) to onabotA and one following (Active) onabotA injections. We found Pre vs. Active onabotA modulation of activity in the amygdala for both happy and angry faces, as well as modulation of activity in the fusiform gyrus for happy faces. Consistent with our predictions, preventing frowning through inhibition of glabellar muscle contraction altered amygdala processing for emotional faces. The modulation of amygdala and fusiform gyrus activity following onabotA may reflect compensatory processes in a neuroanatomical circuit involved in emotional processing that is engaged when facial feedback is impaired. These data contribute to a growing literature suggesting that inhibition of glabellar muscle contraction alters neural activity for emotional processing.Clinical Trials.gov registration number: NCT03373162.
Remote-refocusing light-sheet fluorescence microscopy enables 3D imaging of electromechanical coupling of hiPSC-derived and adult cardiomyocytes in co-culture
Authors: Dvinskikh L. , Sparks H. , Brito L. , MacLeod K. T. , Harding S. E. , Dunsby C. 
Published: February 2023

AbstractImproving cardiac function through stem-cell regenerative therapy requires functional and structural integration of the transplanted cells with the host tissue. Visualizing the electromechanical interaction between native and graft cells necessitates 3D imaging with high spatio-temporal resolution and low photo-toxicity. A custom light-sheet fluorescence microscope was used for volumetric imaging of calcium dynamics in co-cultures of adult rat left ventricle cardiomyocytes and human induced pluripotent stem cell-derived cardiomyocytes. Aberration-free remote refocus of the detection plane synchronously to the scanning of the light sheet along the detection axis enabled fast dual-channel 3D imaging at subcellular resolution without mechanical sample disturbance at up to 8 Hz over a ∼300 µm × 40 µm × 50 µm volume. The two cell types were found to undergo electrically stimulated and spontaneous synchronized calcium transients and contraction. Electromechanical coupling improved with co-culture duration, with 50% of adult-CM coupled after 24 h of co-culture, compared to 19% after 4 h (p = 0.0305). Immobilization with para-nitroblebbistatin did not prevent calcium transient synchronization, with 35% and 36% adult-CM coupled in control and treated samples respectively (p = 0.91), indicating that electrical coupling can be maintained independently of mechanotransduction.
Fragmentation and correlations in a rotating Bose–Einstein condensate undergoing breakup
Authors: Dutta Sunayana , Lode Axel U. J. , Alon Ofir E. 
Published: February 2023

AbstractThe theoretical investigation of rotating Bose–Einstein condensates has mainly focused on the emergence of quantum vortex states and the condensed properties of such systems. In the present work, we concentrate on other facets by examining the impact of rotation on the ground state of weakly interacting bosons confined in anharmonic potentials computed both at the mean-field level and particularly at the many-body level of theory. For the many-body computations, we employ the well-established many-body method known as the multiconfigurational time-dependent Hartree method for bosons. We present how various degrees of fragmentation can be generated following the breakup of the ground state densities in anharmonic traps without ramping up a potential barrier for strong rotations. The breakup of the densities is found to be associated with the acquisition of angular momentum in the condensate due to the rotation. In addition to fragmentation, the presence of many-body correlations is examined by computing the variances of the many-particle position and momentum operators. For strong rotations, the many-body variances become smaller than their mean-field counterparts, and one even finds a scenario with opposite anisotropies of the mean-field and many-body variances. Further, it is observed that for higher discrete symmetric systems of order k, namely three-fold and four-fold symmetry, breakup to k sub-clouds and emergence of k-fold fragmentation take place. All in all, we provide a thorough many-body investigation of how and which correlations build up when a trapped Bose–Einstein condensate breaks up under rotation.
Disentangling the personality pathways to well-being
Authors: Moreira Paulo A. S. , Inman Richard A. , Cloninger C. Robert 
Published: February 2023

AbstractRecent genomic, psychological, and developmental research shows that human personality is organized as a complex hierarchy that ascends from individual traits in many specific situations to multi-trait profiles in two domains that regulate emotional reactivity (temperament) or goals and values (character), and finally to three integrated temperament-character networks that regulate learning to maintain well-being in changing conditions. We carried out person-centered analyses of the components of subjective well-being (positive affect, negative affect, and life satisfaction) to personality in both adolescents (N = 1739) and adults (N = 897). Personality was considered at each level of its organization (trait, temperament or character profiles, and joint temperament-character networks). We show for the first time that negative affect and life satisfaction are dependent on the personality network for intentional self-control, whereas positive affect is dependent on the personality network for self-awareness that underlies the human capacities for healthy longevity, creativity, and prosocial values.
Risk perception and gratitude mediate the negative relationship between COVID-19 management satisfaction and public anxiety
Authors: Mei Ying , Tan Lisha , Yang Wenmin , Luo Jie , Xu Lei , Lei Yi , Li Hong 
Published: February 2023

AbstractIn this study, we explored whether satisfaction with government management, perception of risk, and gratitude influenced public anxiety during the COVID-19 pandemic in China. Using a cross-sectional, anonymous and confidential online survey, a nationwide sample of Chinese adults (N = 876) was targeted between March 25–March 30, 2020, a period in which newly confirmed cases significantly declined in China. The anxiety level was decreased as compared to that assessed during the peak period. Multiple parallel mediation modeling demonstrated that risk perception and gratitude partially mediated the relationship between satisfaction with government management and public anxiety. Increasing satisfaction and gratitude, as well as reducing risk perception contribute to the public’s mental health. The results may shed light on the positive factors for psychological well-being during the COVID-19 pandemic and may aid potential strategies for the policy maker, the public, and the clinic to regulate negative emotions or future emerging infectious diseases.
Delta (B1.617.2) variant of SARS-CoV-2 induces severe neurotropic patterns in K18-hACE2 mice
Authors: Yang Ju-Hee , Yang Myeon-Sik , Kim Dae-Min , Kim Bumseok , Tark Dongseob , Kang Sang-Min , Lee Gun-Hee 
Published: February 2023

AbstractA highly contagious virus, severe acute respiratory syndrome coronavirus 2, caused the coronavirus disease 19 (COVID-19) pandemic (SARS-CoV-2). SARS-CoV-2 genetic variants have been reported to circulate throughout the COVID-19 pandemic. COVID-19 symptoms include respiratory symptoms, fever, muscle pain, and breathing difficulty. In addition, up to 30% of COVID-19 patients experience neurological complications such as headaches, nausea, stroke, and anosmia. However, the neurotropism of SARS-CoV-2 infection remains largely unknown. This study investigated the neurotropic patterns between the B1.617.2 (Delta) and Hu-1 variants (Wuhan, early strain) in K18-hACE2 mice. Despite both the variants inducing similar pathogenic patterns in various organs, B1.617.2-infected K18-hACE2 mice demonstrated a higher range of disease phenotypes such as weight loss, lethality, and conjunctivitis when compared to those in Hu-1-infected mice. In addition, histopathological analysis revealed that B1.617.2 infects the brain of K18-hACE2 mice more rapidly and effectively than Hu-1. Finally, we discovered that, in B1.617.2-infected mice, the early activation of various signature genes involved innate cytokines and that the necrosis-related response was most pronounced than that in Hu-1-infected mice. The present findings indicate the neuroinvasive properties of SARS-CoV-2 variants in K18-hACE2 mice and link them to fatal neuro-dissemination during the disease onset.
Deep learning augmented ECG analysis to identify biomarker-defined myocardial injury
Authors: Chaudhari Gunvant R. , Mayfield Jacob J. , Barrios Joshua P. , Abreau Sean , Avram Robert , Olgin Jeffrey E. , Tison Geoffrey H. 
Published: February 2023

AbstractChest pain is a common clinical complaint for which myocardial injury is the primary concern and is associated with significant morbidity and mortality. To aid providers’ decision-making, we aimed to analyze the electrocardiogram (ECG) using a deep convolutional neural network (CNN) to predict serum troponin I (TnI) from ECGs. We developed a CNN using 64,728 ECGs from 32,479 patients who underwent ECG within 2 h prior to a serum TnI laboratory result at the University of California, San Francisco (UCSF). In our primary analysis, we classified patients into groups of TnI < 0.02 or ≥ 0.02 µg/L using 12-lead ECGs. This was repeated with an alternative threshold of 1.0 µg/L and with single-lead ECG inputs. We also performed multiclass prediction for a set of serum troponin ranges. Finally, we tested the CNN in a cohort of patients selected for coronary angiography, including 3038 ECGs from 672 patients. Cohort patients were 49.0% female, 42.8% white, and 59.3% (19,283) never had a positive TnI value (≥ 0.02 µg/L). CNNs accurately predicted elevated TnI, both at a threshold of 0.02 µg/L (AUC = 0.783, 95% CI 0.780–0.786) and at a threshold of 1.0 µg/L (AUC = 0.802, 0.795–0.809). Models using single-lead ECG data achieved significantly lower accuracy, with AUCs ranging from 0.740 to 0.773 with variation by lead. Accuracy of the multi-class model was lower for intermediate TnI value-ranges. Our models performed similarly on the cohort of patients who underwent coronary angiography. Biomarker-defined myocardial injury can be predicted by CNNs from 12-lead and single-lead ECGs.
Serial dependencies between locomotion and visual space
Authors: Wiesing Michael , Zimmermann Eckart 
Published: February 2023

AbstractHow do we know the spatial distance of objects around us? Only by physical interaction within an environment can we measure true physical distances. Here, we investigated the possibility that travel distances, measured during walking, could be used to calibrate visual spatial perception. The sensorimotor contingencies that arise during walking were carefully altered using virtual reality and motion tracking. Participants were asked to walk to a briefly highlighted location. During walking, we systematically changed the optic flow, i.e., the ratio between the visual and physical motion speed. Although participants remained unaware of this manipulation, they walked a shorter or longer distance as a function of the optic flow speed. Following walking, participants were required to estimate the perceived distance of visual objects. We found that visual estimates were serially dependent on the experience of the manipulated flow in the previous trial. Additional experiments confirmed that to affect visual perception, both visual and physical motion are required. We conclude that the brain constantly uses movements to measure space for both, actions, and perception.