Supramolecular Complexation Reinforced Polymer Frustrated Packing: Controllable Dual Porosity for Improved Permselectivity of Coordination Nanocage Mixed Matrix Membranes

The developments of mixed matrix membranes (MMMs) are severely hindered by the complex inter-phase interaction and the resulting poor utilization of inorganics' microporosity. Herein, a dual porosity framework is constructed in MMMs to enhance the accessibility of inorganics' microporosity to external gas molecules for the effective application of microporosity for gas separation. Nanocomposite organogels are first prepared from the supramolecular complexation of rigid polymers and 2 nm microporous coordination nanocages (CNCs). The network structures can be maintained with microporous features after solvent removal originated from the rigid nature of polymers, and the strong coordination and hydrogen bond between the two components. Moreover, the strong supramolecular attraction reinforces the frustrated packing of the rigid polymers on CNC surface, leading to polymer networks' extrinsic pores and the interconnection of CNCs' micro-cavities for the fast gas transportation. The gas permeabilities of the MMMs are 869 times for H2 and 1099 times for CO2 higher than those of pure polymers. The open metal sites from nanocage also contribute to the enhanced gas selectivity and the overall performance surpasses 2008 H2/CO2 Robeson upper bound. The supramolecular complexation reinforced packing frustration strategy offers a simple and practical solution to achieve improved gas permselectivity in MMMs.

Exploration of Molecular Nanoparticles as Soft Structural Materials and Their Structure-Property Relationship

The search for alternative chemical systems other than polymers with chain topologies for soft structural materials raises general interests in fundamental materials and chemical sciences. It is also appealing from an engineering perspective for the urgent need to resolve the typical trade-offs of polymer systems. Herein, a subnanometer molecular cluster, polyhedral oligomeric silsesquioxanes, is assembled into molecular nanoparticles (MNPs) with star topology. Broadly tunable viscoelasticity can be realized by fine-tuning the MNPs' deformability. Being analogous to polymeric systems, the hierarchical structural relaxation dynamics can be observed, and their relaxation time and temperature dependence are dominated by the linker flexibilities. This not only provides microscopic understanding on MNP's unique viscoelasticity but also offers enormous opportunities for modulating their mechanical properties via linker engineering. Our work proves the possibility of applying structural units with particle topologies for the design of soft structural materials.

Particle topology-regulated relaxation dynamics in cluster-ordering

The granular materials of soft particles (SPs) demonstrate unique viscoelasticity distinct from general colloidal and polymer systems. Exploiting dynamic light scattering measurements, together with molecular dynamics simulations, we study the diffusive dynamics of soft particle clusters (SPCs) with spherical and cylindrical brush topologies, respectively, in the melts of SPs. A topologically constrained relaxation theory is proposed by quantitatively correlating the relaxation time to the topologies of the SPCs, through the mean free space (Va) of tethered SPs in the cluster. The tethered SPs in SPCs are crowded by SPs of the melts to form the cage zones, and the cooperative diffusion of the tether SPs in the zones is required for the diffusive motion of SPCs. The cage zone serves as an entropic barrier for the diffusion of SP clusters, while its strength is determined by Va. Three characteristic modes can be confirmed: localized non-diffusive mode around critical Va, diffusive mode with Va deviating far from the critical value, and a sub-diffusive mode as an interlude between two limits. Our studies raise attention to the emergent physical properties of materials based on SPs via a topological design while opening new avenues for the design of soft structural materials.

Photoresponsive Viscoelasticity of the Granular Materials of Azobenzene-Bearing Molecular Nanoparticles

The large sizes of granular particles lead to their slow diffusive dynamics and significant interparticle friction, bringing enormous difficulty to tune the mechanical properties and processability of the granular materials (GMs). Herein, 1 nm polyhedral oligomeric silsesquioxane (POSS) particles functionalized with azobenzene are designed as structural units, and the obtained GMs show unique photoswitchable viscoelasticity. The azobenzene group can undergo a reversible trans-cis conformation switch while the π-π stacking among the azobenzene fragments is only favored by the trans-conformation due to molecular geometrical requirements. The POSS units from neighboring assemblies close pack to form microdomains, and the POSS is under confinement by both the supramolecular bonding and the other POSS in the microdomains. The simultaneous breaking of the two types of confinement is difficult and, therefore, the free diffusion of POSS is hindered, leading to the elasticity of the GMs of trans-POSS. For cis-POSS, the interparticle supramolecular interaction is weak and the POSS unit can undergo free diffusion, contributing to their high flowability at room temperature. The photoswitching viscoelasticity of GMs is further used for self-healing and photoswitchable adhesion. This work paves new pathways for the regulation of material viscoelasticity and the design of GM-based smart materials.

Exploring the role of histone deacetylase inhibitors in cancer development and therapeutic potential

The process of acetylation and deacetylation of histones within the nucleus operates within a dynamic equilibrium. Histone acetyltransferases (HATs) and histone deacetylases (HDACs) collaboratively and precisely regulate normal gene transcription and expression. Any disorder in the activity of HATs/HDACs can lead to uncontrolled gene expression, consequently resulting in tumorigenesis. Histone deacetylase inhibitors (HDACIs) have the capacity to block the cell cycle, thereby restraining tumor cell proliferation and tumor growth. Also, HDACIs exhibit a significant capability to diminish the expression of apoptosis protein inhibitors such as Bcl-2 and B-cell lymphoma-extra-large (Bcl-xL), while concurrently up-regulating pro-apoptotic proteins such as Bax, Bad, and Bim. Also, HDACIs demonstrate the ability to inhibit tumor cell angiogenesis. Representing a new category of targeted anti-cancer therapeutics, HDACIs possess the capability to restore the expression of tumor suppressor genes, induce apoptosis, and stimulate cell differentiation. Additionally, they exert anti-cancer effects through diverse pathways both in vivo and in vitro, thereby presenting promising prospects in tumor therapy. This review delves into the involvement of HDACs in cancer pathology and the therapeutic potential of HDACIs as emerging drugs in cancer treatment.

Study of High-Transverse-Momentum Higgs Boson Production in Association with a Vector Boson in the qqbb Final State with the ATLAS Detector

This Letter presents the first study of Higgs boson production in association with a vector boson (V=W or Z) in the fully hadronic qqbb final state using data recorded by the ATLAS detector at the LHC in proton-proton collisions at sqrt[s]=13  TeV and corresponding to an integrated luminosity of 137  fb^{-1}. The vector bosons and Higgs bosons are each reconstructed as large-radius jets and tagged using jet substructure techniques. Dedicated tagging algorithms exploiting b-tagging properties are used to identify jets consistent with Higgs bosons decaying into bb[over ¯]. Dominant backgrounds from multijet production are determined directly from the data, and a likelihood fit to the jet mass distribution of Higgs boson candidates is used to extract the number of signal events. The VH production cross section is measured inclusively and differentially in several ranges of Higgs boson transverse momentum: 250-450, 450-650, and greater than 650 GeV. The inclusive signal yield relative to the standard model expectation is observed to be μ=1.4_{-0.9}^{+1.0} and the corresponding cross section is 3.1±1.3(stat)_{-1.4}^{+1.8}(syst)  pb.

Unique Viscoelasticity and Hierarchical Relaxation Dynamics of Molecular Granular Materials

Resulting from the dense packing of subnanometer molecular clusters, molecular granular materials (MGMs) are shown to maintain high elasticity far above their apparent glass transition temperature (Tg*). However, our microscopic understanding of their structure-property relationship is still poor. Herein, 1 nm polyhedral oligomeric silsesquioxanes (POSSs) are appended to a backbone chain in a brush configuration with different flexible linker chains. Assemblies of these brush polymers exhibit hierarchical relaxation dynamics with the glass transition arising from the cooperative dynamics of packed POSSs. The interaction among the assemblies can be strengthened by increasing the rigidity of linkers with the MGM relaxation modes changing from colloid- to polymer chain-like behavior, rendering their tunable viscoelasticity. This finally contributes to the decoupling of mechanical and thermal properties by showing elasticity dominant mechanical properties at a temperature 150 K above the Tg*.

The influence of respiratory movement on preoperative CT-guided localization of lung nodules

AIM

To evaluate the motion amplitude of lung nodules in different locations during preoperative computed tomography (CT)-guided localization, and the influence of respiratory movement on CT-guided percutaneous lung puncture.

MATERIALS AND METHODS

A consecutive cohort of 398 patients (123 men and 275 women with a mean age of 53.9 ± 10.7 years) who underwent preoperative CT-guided lung nodule localization from May 2021 to Apr 2022 were included in this retrospective study. The respiratory movement-related nodule amplitude in the cranial-caudal direction during the CT scan, characteristics of patients, lesions, and procedures were statistically analyzed. Univariate and multivariate logistic regression analyses were used to evaluate the influence of these factors on CT-guided localization.

RESULTS

The nodule motion distribution showed a statistically significant correlation within the upper/middle (lingular) and lower lobes (p<0.001). Motion amplitude was an independent risk factor for CT scan times (p=0.011) and procedure duration (p=0.016), but not for the technical failure rates or the incidence of complications. Puncture depth was an independent risk factor for the CT scan times, procedure duration, technical failure rates, and complications (p<0.01). Female, prone, and supine (as opposed to lateral) positions were significant protective factors for pneumothorax, while the supine position was an independent risk factor for parenchymal hemorrhage (p=0.025).

CONCLUSION

Respiratory-induced motion amplitude of nodules was greater in the lower lobes, resulting in more CT scan times/radiation dose and longer localization duration, but showed no statistically significant influence on the technical success rates or the incidence of complications during preoperative CT-guided localization.

Supramolecular Complexation of Metal Oxide Cluster and Non-Fluorinated Polymer for Large-Scale Fabrication of Proton Exchange Membranes for High-Power-Density Fuel Cells

Cost-effective, non-fluorinated polymer proton exchange membranes (PEMs) are highly desirable in emerging hydrogen fuel cells (FCs) technology; however, their low proton conductivities and poor chemical and dimension stabilities hinder their further development as alternatives to commercial Nafion®. Here, we report the inorganic-organic hybridization strategy by facilely complexing commercial polymers, polyvinyl butyral (PVB), with inorganic molecular nanoparticles, H3 PW12 O40 (PW) via supramolecular interaction. The strong affinity among them endows the obtained nanocomposites amphiphilicity and further lead to phase separation for bi-continuous structures with both inter-connected proton transportation channels and robust polymer scaffold, enabling high proton conductivities, mechanical/dimension stability and barrier performance, and the H2 /O2 FCs equipped with the composite PEM show promising power densities and long-term stability. Interestingly, the hybrid PEM can be fabricated continuously in large scale at challenging ~10 μm thickness via typical tape casting technique originated from their facile complexing strategy and the hybrids' excellent mechanical properties. This work not only provides potential material systems for commercial PEMs, but also raises interest for the research on hybrid composites for PEMs.

[Disease burden of acute viral hepatitis in Guangdong Province, 1990-2019]

Objective: To examine the burden and trends of acute viral hepatitis in Guangdong Province from 1990 to 2019, and provide reference evidences for hepatitis prevention and control in the province. Methods: Data on acute viral hepatitis (hepatitis A, B, C, and E) in Guangdong from 1990 to 2019 were extracted from the Global Burden of Disease Study 2019 database. The incidence, prevalence, mortality, and disability-adjusted life years (DALY) data were analyzed by age and gender, and the estimated annual percentage change (EAPC) was calculated to describe the changing trends in disease burden. Results: From 1999 to 2019, the standardized incidence, prevalence, mortality, and DALY of acute viral hepatitis in Guangdong were higher than the national averages. In 2019, 51.43% (2 245 087/4 365 221) of acute viral hepatitis cases in Guangdong Province were mainly attributed to hepatitis B, and 77.18% (106/138) of deaths were due to acute hepatitis B. In different age groups, except for acute hepatitis B, which was more common in adults, the incidence rates of other types of viral hepatitis such as hepatitis A, B, and E showed an overall decreasing trend with age. The mortality rates of different types of acute viral hepatitis, except for the <5 age group, increased with age. The overall incidence and mortality rates of acute viral hepatitis were higher in men than in women. Conclusions: The overall burden of acute viral hepatitis in Guangdong declined in 2019, but remained higher than the national level. Further efforts are needed to strengthen hepatitis prevention and screening in different population in Guangdong Province, especially in children and the elderly.

Measurement of the Centrality Dependence of the Dijet Yield in p+Pb Collisions at sqrt[s_{NN}]=8.16 TeV with the ATLAS Detector

ATLAS measured the centrality dependence of the dijet yield using 165  nb^{-1} of p+Pb data collected at sqrt[s_{NN}]=8.16  TeV in 2016. The event centrality, which reflects the p+Pb impact parameter, is characterized by the total transverse energy registered in the Pb-going side of the forward calorimeter. The central-to-peripheral ratio of the scaled dijet yields, R_{CP}, is evaluated, and the results are presented as a function of variables that reflect the kinematics of the initial hard parton scattering process. The R_{CP} shows a scaling with the Bjorken x of the parton originating from the proton, x_{p}, while no such trend is observed as a function of x_{Pb}. This analysis provides unique input to understanding the role of small proton spatial configurations in p+Pb collisions by covering parton momentum fractions from the valence region down to x_{p}∼10^{-3} and x_{Pb}∼4×10^{-4}.

Search for New Phenomena in Two-Body Invariant Mass Distributions Using Unsupervised Machine Learning for Anomaly Detection at sqrt[s]=13 TeV with the ATLAS Detector

Searches for new resonances are performed using an unsupervised anomaly-detection technique. Events with at least one electron or muon are selected from 140  fb^{-1} of pp collisions at sqrt[s]=13  TeV recorded by ATLAS at the Large Hadron Collider. The approach involves training an autoencoder on data, and subsequently defining anomalous regions based on the reconstruction loss of the decoder. Studies focus on nine invariant mass spectra that contain pairs of objects consisting of one light jet or b jet and either one lepton (e,μ), photon, or second light jet or b jet in the anomalous regions. No significant deviations from the background hypotheses are observed. Limits on contributions from generic Gaussian signals with various widths of the resonance mass are obtained for nine invariant masses in the anomalous regions.

Strain-Induced Heteromorphosis Multi-Cavity Cages: Tension-Driven Self-Expansion Strategy for Controllable Enhancement of Complexity in Supramolecular Assembly

Coordinative supramolecular cages with adjustable cavities have found extensive applications in various fields, but the cavity modification strategies for multi-functional structures are still challenging. Here, we present a tension-driven self-expansion strategy for construction of multi-cavity cages with high structural complexity. Under the regulation of strain-induced capping ligands, unprecedented heteromorphosis triple-cavity cages S2 /S4 were obtained based on a metallo-organic ligand (MOL) scaffold. The heteromorphosis cages exhibited significant higher cavity diversity than the homomorphous double-cavity cages S1 /S3 ; all of the cages were thoroughly characterized through various analytical techniques including (1D and 2D) NMR, ESI-MS, TWIM-MS, AFM, and SAXS analyses. Furthermore, the encapsulation of porphyrin in the cavities of these multi-cavity cages were investigated. This research opens up new possibilities for the architecture of heteromorphosis supramolecular cages via precisely controlled "scaffold-capping" assembly with preorganized ligands, which could have potential applications in the development of multifunctional structures with higher complexity.

Polyoxometalate-Organic Hybrid "Calixarenes" as Supramolecular Hosts

Calixarenes are among the most useful and versatile macrocycles in supramolecular chemistry. The one thing that has not changed in the 80 years since their discovery, despite numerous derivatizations, is their fully organic, covalent scaffolds. Here, we report a new type of organic-inorganic hybrid "calixarenes" constructed by means of coordination-driven assembly. Replacing acetate ligands on the {SiW10 Cr2 (OAc)2 } clusters with 5-hydroxyisophthalates allows these 95° inorganic building blocks to be linked into bowl-shaped, hybrid "calix[n]arenes" (n=3, 4). With a large concave cavity, the metal-organic calix[4]arene can accommodate nanometer-sized polyoxoanions in an entropically driven process. The development of hybrid variants of calixarenes is expected to expand the scope of their physicochemical properties, guest/substrate binding, and applications on multiple fronts.

Observation of WZγ Production in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector

This Letter reports the observation of WZγ production and a measurement of its cross section using 140.1±1.2  fb^{-1} of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. The WZγ production cross section, with both the W and Z bosons decaying leptonically, pp→WZγ→ℓ^{'}^{±}νℓ^{+}ℓ^{-}γ (ℓ^{(^{'})}=e, μ), is measured in a fiducial phase-space region defined such that the leptons and the photon have high transverse momentum and the photon is isolated. The cross section is found to be 2.01±0.30(stat)±0.16(syst)  fb. The corresponding standard model predicted cross section calculated at next-to-leading order in perturbative quantum chromodynamics and at leading order in the electroweak coupling constant is 1.50±0.06  fb. The observed significance of the WZγ signal is 6.3σ, compared with an expected significance of 5.0σ.

[Cardiovascular diseases burden attributed to low physical activity in China, 1990-2019]

Objective: To analyze the burden of cardiovascular disease (CVD) attributed to low physical activity (LPA) and its changing trends in China from 1990 to 2019. Methods: On the basis of the province results of the Study of Global Burden of Disease 2019 in China, we described the distribution of CVD death and disability-adjusted life year (DALY) attributed to LPA by sex, age and province. Joinpoint 4.9.1.0 was used to calculate the average annual percentage change. Results: In 2019, the number of CVD deaths and DALY attributed to LPA in people aged ≥25 years were 0.127 million and 1.863 million person-years in China, respectively, The age-standardized mortality rate (ASMR) and standardized DALY rate of CVD attributed to LPA were slightly higher in men than in women, and much higher in ischemic heart disease patients than in ischemic stroke patients. The ASMR (8.85/100 000) and the standardized DALY rate (112.34/100 000) of CVD attributed to LPA in China in 2019 showed no obvious change compared with 1990, while decreased in the last decade. The largest increases in the mortality rate and DALY rate were observed in people aged ≥75 years from 1990 to 2019 (26.89%, 15.61%), but the mortality rate and DALY rate in people aged 60-74 years showed a decreasing trend. The mortality rate and DALY rate in men aged 25- 44 years showed the largest increases (37.50%, 35.49%), while women aged ≥75 years had the largest increases (31.00%, 18.02%). In 2019, the highest ASMR and standardized DALY rate of CVD attributed to LPA were found in Jilin, Inner Mongolia and Hebei. The largest increases were found in Qinghai (182.41%, 154.70%), Gansu (181.29%, 152.77%), and Chongqing (132.01%, 102.79%) and the largest decreases were found in Beijing (59.11%, 62.09%), Macau (41.89%, 39.37%) and Guangdong (36.93%, 40.72%) from 1990 to 2019. Conclusion: The disease burden of CVD attributed to LPA in China was quite high and showed gender, age and area specific differences.

Spatiotemporal Studies of Soluble Inorganic Nanostructures with X-rays and Neutrons

This Review addresses the use of X-ray and neutron scattering as well as X-ray absorption to describe how inorganic nanostructured materials assemble, evolve, and function in solution. We first provide an overview of techniques and instrumentation (both large user facilities and benchtop). We review recent studies of soluble inorganic nanostructure assembly, covering the disciplines of materials synthesis, processes in nature, nuclear materials, and the widely applicable fundamental processes of hydrophobic interactions and ion pairing. Reviewed studies cover size regimes and length scales ranging from sub-Ångström (coordination chemistry and ion pairing) to several nanometers (molecular clusters, i.e. polyoxometalates, polyoxocations, and metal-organic polyhedra), to the mesoscale (supramolecular assembly processes). Reviewed studies predominantly exploit 1) SAXS/WAXS/SANS (small- and wide-angle X-ray or neutron scattering), 2) PDF (pair-distribution function analysis of X-ray total scattering), and 3) XANES and EXAFS (X-ray absorption near-edge structure and extended X-ray absorption fine structure, respectively). While the scattering techniques provide structural information, X-ray absorption yields the oxidation state in addition to the local coordination. Our goal for this Review is to provide information and inspiration for the inorganic/materials science communities that may benefit from elucidating the role of solution speciation in natural and synthetic processes.

Spatial distribution, movement, body damage, and feather condition of laying hens in a multi-tier system

The welfare and health of laying hens in the multitier system raise concern in public. The flock distributions during feeding time at 51 and 89 wk were studied in a multitier system. Furthermore, the ultra-high frequency radio frequency identification (UHF RFID) equipment was used to identify the transition between tiers and time spent in each tier of 48 focal hens (12 hens from each tier-group of the multitier system) at 92 wk of age. The body weight, tibia size (length and width), body damage (comb and rear part), and feather condition (neck, breast, back, tail, cloaca, and wings) of focal hens from different tier-groups were further compared. The results showed that the spatial distribution in flocks changed from top to bottom with increasing age. The hens at 51 wk of age were mainly distributed in the 4th tier (19.6 ± 5.0% in 1st tier, 9.6 ± 1.1% in 2nd tier, 23.6 ± 2.9% in 3rd tier and 47.3 ± 2.6% in 4th tier), and hens at 89 wk of age were mainly distributed in the lower tiers (33.5 ± 1.5% in 1st tier, 31.9 ± 5.1% in 2nd tier, 15.7 ± 3.4% in 3rd tier and 16.6 ± 3.1% in 4th tier). The spatial distribution of hens at 89 wk of age was more even than that at 51 wk of age. At 92 wk of age, the proportion of time spent in original tier of 4 tier-groups was 91.0 ± 5.7%, 51.9 ± 5.7%, 59.0 ± 7.0% and 63.0 ± 6.7%, respectively. Focal hens preferred to stay in the original tier and spent significantly less time in other tiers (P < 0.05). There was no significant difference in body weight, body damage score, tibia width and partial feather scores (neck, breast, tail, and cloaca) of focal hens among 4 tier-groups (P > 0.05). However, focal hens from 1st tier had worse feather scores on wings and back, and shorter tibia length compared to other tiers suggesting that there were more lower ranking birds that located in lower tier to avoid competition, but had equal access to resource, which is good for their welfare and health. In summary, the overcrowding situation was improved near the end of the laying cycle in the multitier system, thereby mitigating the potential negative effects to the lower ranking hens and maintain a satisfactory level of welfare and health for laying hens near the end of the laying cycle.

Controllable and Reversible Assembly of Nanofiber from Natural Macromolecules via Protonation and Deprotonation

Nanofiber is the critical building block for many biological systems to perform various functions. Artificial assembly of molecules into nanofibers in a controllable and reversible manner will create "smart" functions to mimic those of their natural analogues and fabricate new functional materials, but remains an open challenge especially for nature macromolecules. Herein, the controllable and reversible assembly of nanofiber (CSNF) from natural macromolecules with oppositely charged groups are successfully realized by protonation and deprotonation of charged groups. By controlling the electrostatic interaction via protonation and deprotonation, the size and morphology of the assembled nanostructures can be precisely controlled. A strong electrostatic interaction contributes to large nanofiber with high strength, while poor electrostatic interaction produces finer nanofiber or nanoparticle. And especially, the assembly, disassembly, and reassembly of the nanofiber occurs reversibly through protonation and deprotonation, thereby paving a new way for precisely controlling the assembly process and structure of nanofiber. The reversible assembly allows the nanostructure to dynamically reorganize in response to subtle perturbation of environment. The as-prepared CSNF is mechanical strong and can be used as a nano building block to fabricate high-strength film, wire, and straw. This study offers many opportunities for the biomimetic synthesis of new functional materials.

Combined Measurement of the Higgs Boson Mass from the H→γγ and H→ZZ^{*}→4ℓ Decay Channels with the ATLAS Detector Using sqrt[s]=7, 8, and 13 TeV pp Collision Data

A measurement of the mass of the Higgs boson combining the H→ZZ^{*}→4ℓ and H→γγ decay channels is presented. The result is based on 140  fb^{-1} of proton-proton collision data collected by the ATLAS detector during LHC run 2 at a center-of-mass energy of 13 TeV combined with the run 1 ATLAS mass measurement, performed at center-of-mass energies of 7 and 8 TeV, yielding a Higgs boson mass of 125.11±0.09(stat)±0.06(syst)=125.11±0.11  GeV. This corresponds to a 0.09% precision achieved on this fundamental parameter of the Standard Model of particle physics.

Search for Dark Photons in Rare Z Boson Decays with the ATLAS Detector

A search for events with a dark photon produced in association with a dark Higgs boson via rare decays of the standard model Z boson is presented, using 139  fb^{-1} of sqrt[s]=13  TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider. The dark boson decays into a pair of dark photons, and at least two of the three dark photons must each decay into a pair of electrons or muons, resulting in at least two same-flavor opposite-charge lepton pairs in the final state. The data are found to be consistent with the background prediction, and upper limits are set on the dark photon's coupling to the dark Higgs boson times the kinetic mixing between the standard model photon and the dark photon, α_{D}ϵ^{2}, in the dark photon mass range of [5, 40] GeV except for the ϒ mass window [8.8, 11.1] GeV. This search explores new parameter space not previously excluded by other experiments.

Modulating Ligand-Exchange Dynamics on Metal-Organic Polyhedra for Reversible Sorting and Hybridization of Miktoarm Star Polymers

The precise synthesis of miktoarm star polymers (MSPs) remains one of the great challenges in synthetic chemistry due to the difficulty in locating appropriate structural templates and polymer grafting/growing strategies with high selectivity and efficiency. Herein, ≈2 nm metal-organic polyhedra (MOPs), constructed from the coordination of isophthalic acid (IPA) and Cu2+ , are applied as templates for the precise synthesis of 24-arm MSPs for their unique logarithmic ligand-exchange dynamics. Six different polymers are prepared with IPA as an end group and they further coordinated with Cu2+ to afford the corresponding 24-arm star homo-polymers. MSPs can be obtained by mixing targeted homo-arm star polymers in solutions upon thermal annealing. The compositions of MSPs can be facilely and precisely tuned by the recipe of the star polymer mixtures used. Interestingly, the obtained MSPs can be sorted into homo-arm star polymers through a typical solvent extraction procedure. The hybridization and sorting process can be reversibly conducted through the cycle of thermal annealing and solvent treatment. The complex coordination framework not only opens new avenues for the facile and precise synthesis of MSPs and MOPs with hybrid functionalities, but also provides the capability to design sustainable polymer systems.

The Coordination Nanocages-Integrated Polymer Brush Networks for Flexible Microporous Membranes with Exceptional H2 /CO2 Separation Performance

The emergence of polymers with intrinsic microporosity provides solutions for flexible gas separation membranes with both high gas permeability and selectivity. However, their applications are significantly hindered by the costly synthetic efforts, limited availability of chemical systems, and narrow window of microporosity sizes. Herein, flexible mixed matrix membranes with tunable intrinsic microporosity can be facilely fabricated from the coordination assembly of polymer brushes and coordination nanocages. Polymer brushes bearing isophthalic acid side groups can coordinate with Cu2+ to assemble into polymer networks crosslinked by 2 nm nanocages. The semi-flexible feature of the polymer brush and the high crosslinking density of the network prevent the network from collapsing during solvent removal and the obtained aerogels demonstrate hierarchical structure with dual porosity from the crosslinked polymer network and coordination nanocage, respectively. The porosity can be facilely tuned via the amount of Cu2+ by regulating the network crosslinking density and nanocage loadings, and finally, optimized gas separation that surpasses Robeson upper bound for H2 /CO2 can be achieved. The coordination-driven assembly protocol paves a new avenue for the cost-effective synthesis of polymers with intrinsic microporosity and the fabrication of flexible gas separation membranes.

Observation of Single-Top-Quark Production in Association with a Photon Using the ATLAS Detector

This Letter reports the observation of single top quarks produced together with a photon, which directly probes the electroweak coupling of the top quark. The analysis uses 139  fb^{-1} of 13 TeV proton-proton collision data collected with the ATLAS detector at the Large Hadron Collider. Requiring a photon with transverse momentum larger than 20 GeV and within the detector acceptance, the fiducial cross section is measured to be 688±23(stat) _{-71}^{+75}(syst)  fb, to be compared with the standard model prediction of 515_{-42}^{+36}  fb at next-to-leading order in QCD.

Correlation of Structure and Dynamics Behavior in Polyzwitterions: From Concentrated Solution to Gel-Like State

The dynamic behaviors of polyzwitterions, poly(4-((3-methacrylamidopropyl) dimethylammonio) butane-1-sulfonate) (PSBP), are investigated using dynamic light scattering, small angle X-ray scattering, and rheology.  The findings reveal two relaxation modes, including a fast and a slow mode, which  are observed in both solution state and gel-like state, with varying polyzwitterion concentration (CP ) and NaCl concentration (CNaCl ). As CP and CNaCl increasing, a slower slow mode and a faster fast mode are observed. The fast mode corresponds to the diffusion of chains, while the slow mode arises from chain aggregations. In solutions, the slow mode is dominated by the diffusion of chain aggregations. However, in the gel-like state, the "cage network" traps aggregations more densely, leading to their dynamic behavior being dominated by enhanced topological entanglements and ionic interactions. This difference highlights the unique nature of the slow relaxation mode between concentrated solution and gel-like state, arising from changes in the average distance between chain aggregations resulting from increased CP and CNaCl concentrations.

Measurement of Suppression of Large-Radius Jets and Its Dependence on Substructure in Pb+Pb Collisions at sqrt[s_{NN}]=5.02 TeV with the ATLAS Detector

This letter presents a measurement of the nuclear modification factor of large-radius jets in sqrt[s_{NN}]=5.02  TeV Pb+Pb collisions by the ATLAS experiment. The measurement is performed using 1.72  nb^{-1} and 257  pb^{-1} of Pb+Pb and pp data, respectively. The large-radius jets are reconstructed with the anti-k_{t} algorithm using a radius parameter of R=1.0, by reclustering anti-k_{t} R=0.2 jets, and are measured over the transverse momentum (p_{T}) kinematic range of 158 Collapse

Key Words Collapse

MESH Headings Collapse

Grants Collapse

Measurement of the Sensitivity of Two-Particle Correlations in pp Collisions to the Presence of Hard Scatterings

A key open question in the study of multiparticle production in high-energy pp collisions is the relationship between the "ridge"-i.e., the observed azimuthal correlations between particles in the underlying event that extend over all rapidities-and hard or semihard scattering processes. In particular, it is not known whether jets or their soft fragments are correlated with particles in the underlying event. To address this question, two-particle correlations are measured in pp collisions at sqrt[s]=13  TeV using data collected by the ATLAS experiment at the LHC, with an integrated luminosity of 15.8  pb^{-1}, in two different configurations. In the first case, charged particles associated with jets are excluded from the correlation analysis, while in the second case, correlations are measured between particles within jets and charged particles from the underlying event. Second-order flow coefficients, v_{2}, are presented as a function of event multiplicity and transverse momentum. These measurements show that excluding particles associated with jets does not affect the measured correlations. Moreover, particles associated with jets do not exhibit any significant azimuthal correlations with the underlying event, ruling out hard processes contributing to the ridge.

Observation of an Excess of Dicharmonium Events in the Four-Muon Final State with the ATLAS Detector

A search is made for potential ccc[over ¯]c[over ¯] tetraquarks decaying into a pair of charmonium states in the four muon final state using proton-proton collision data at sqrt[s]=13  TeV, corresponding to an integrated luminosity of 140  fb^{-1} recorded by the ATLAS experiment at LHC. Two decay channels, J/ψ+J/ψ→4μ and J/ψ+ψ(2S)→4μ, are studied. Backgrounds are estimated based on a hybrid approach involving Monte Carlo simulations and data-driven methods. Statistically significant excesses with respect to backgrounds dominated by the single parton scattering are seen in the di-J/ψ channel consistent with a narrow resonance at 6.9 GeV and a broader structure at lower mass. A statistically significant excess is also seen in the J/ψ+ψ(2S) channel. The fitted masses and decay widths of the structures are reported.

Observation of the γγ→ττ Process in Pb+Pb Collisions and Constraints on the τ-Lepton Anomalous Magnetic Moment with the ATLAS Detector

This Letter reports the observation of τ-lepton-pair production in ultraperipheral lead-lead collisions Pb+Pb→Pb(γγ→ττ)Pb and constraints on the τ-lepton anomalous magnetic moment a_{τ}. The dataset corresponds to an integrated luminosity of 1.44  nb^{-1} of LHC Pb+Pb collisions at sqrt[s_{NN}]=5.02  TeV recorded by the ATLAS experiment in 2018. Selected events contain one muon from a τ-lepton decay, an electron or charged-particle track(s) from the other τ-lepton decay, little additional central-detector activity, and no forward neutrons. The γγ→ττ process is observed in Pb+Pb collisions with a significance exceeding 5 standard deviations and a signal strength of μ_{ττ}=1.03_{-0.05}^{+0.06} assuming the standard model value for a_{τ}. To measure a_{τ}, a template fit to the muon transverse-momentum distribution from τ-lepton candidates is performed, using a dimuon (γγ→μμ) control sample to constrain systematic uncertainties. The observed 95% confidence-level interval for a_{τ} is -0.057 Collapse

Key Words Collapse

MESH Headings Collapse

Grants Collapse

Strong Constraints on Jet Quenching in Centrality-Dependent p+Pb Collisions at 5.02 TeV from ATLAS

Jet quenching is the process of color-charged partons losing energy via interactions with quark-gluon plasma droplets created in heavy-ion collisions. The collective expansion of such droplets is well described by viscous hydrodynamics. Similar evidence of collectivity is consistently observed in smaller collision systems, including pp and p+Pb collisions. In contrast, while jet quenching is observed in Pb+Pb collisions, no evidence has been found in these small systems to date, raising fundamental questions about the nature of the system created in these collisions. The ATLAS experiment at the Large Hadron Collider has measured the yield of charged hadrons correlated with reconstructed jets in 0.36  nb^{-1} of p+Pb and 3.6  pb^{-1} of pp collisions at 5.02 TeV. The yields of charged hadrons with p_{T}^{ch}>0.5  GeV near and opposite in azimuth to jets with p_{T}^{jet}>30 or 60 GeV, and the ratios of these yields between p+Pb and pp collisions, I_{pPb}, are reported. The collision centrality of p+Pb events is categorized by the energy deposited by forward neutrons from the struck nucleus. The I_{pPb} values are consistent with unity within a few percent for hadrons with p_{T}^{ch}>4  GeV at all centralities. These data provide new, strong constraints that preclude almost any parton energy loss in central p+Pb collisions.

Search for Heavy Neutral Leptons in Decays of W Bosons Using a Dilepton Displaced Vertex in sqrt[s]=13 TeV pp Collisions with the ATLAS Detector

A search for a long-lived, heavy neutral lepton (N) in 139  fb^{-1} of sqrt[s]=13  TeV pp collision data collected by the ATLAS detector at the Large Hadron Collider is reported. The N is produced via W→Nμ or W→Ne and decays into two charged leptons and a neutrino, forming a displaced vertex. The N mass is used to discriminate between signal and background. No signal is observed, and limits are set on the squared mixing parameters of the N with the left-handed neutrino states for the N mass range 3  GeV Collapse

Key Words Collapse

MESH Headings Collapse

Grants Collapse

Test of CP Invariance in Higgs Boson Vector-Boson-Fusion Production Using the H→γγ Channel with the ATLAS Detector

A test of CP invariance in Higgs boson production via vector-boson fusion has been performed in the H→γγ channel using 139  fb^{-1} of proton-proton collision data at sqrt[s]=13  TeV collected by the ATLAS detector at the LHC. The optimal observable method is used to probe the CP structure of interactions between the Higgs boson and electroweak gauge bosons, as described by an effective field theory. No sign of CP violation is observed in the data. Constraints are set on the parameters describing the strength of the CP-odd component in the coupling between the Higgs boson and the electroweak gauge bosons in two effective field theory bases: d[over ˜] in the HISZ basis and c_{HW[over ˜]} in the Warsaw basis. The results presented are the most stringent constraints on CP violation in the coupling between Higgs and weak bosons. The 95% C.L. constraint on d[over ˜] is derived for the first time and the 95% C.L. constraint on c_{HW[over ˜]} has been improved by a factor of 5 compared to the previous measurement.

[Analysis of therapeutic mechanism of Liushen Wan against colitis-associated colorectal cancer based on network pharmacology and validation in mice]

OBJECTIVE

To explore the therapeutic mechanism of Liushen Wan (LSW) against colitis-associated colorectal cancer (CAC) by network pharmacology.

METHODS

TCMSP, BATMAN-TCM, CNKI, PubMed, Genecards, OMIM, and TTD databases were used to obtain the related targets of LSW and CAC. The common targets of LSW and CAC were obtained using Venny online website. The PPI network was constructed using Cytoscape 3.8.2 to screen the core targets of LSW in the treatment of CAC. GO and KEGG enrichment analysis were conducted using DAVID database. The therapeutic effect of LSW on CAC was evaluated in a C57BL/6J mouse model of AOM/DSS-induced CAC by observing the changes in body weight, disease activity index, colon length, and size and number of the tumor. HE staining and RT-qPCR were used to analyze the effect of LSW on inflammatory mediators. Immunohistochemistry and TUNEL staining were used to evaluate the effect of LSW on the proliferation and apoptosis of AOM/DSS-treated colon tumor cells. Immunohistochemistry and Western blotting were used to detect the effects of LSW on the expression of TLR4 proteins in CAC mice.

RESULTS

Network pharmacology analysis identified 69 common targets of LSW and CAC, and 33 hub targets were screened in the PPI network. KEGG pathway enrichment analysis suggested that the effect of LSW on CAC was mediated by the Toll-like receptor signaling pathway. In the mouse model of AOM/DSS-induced CAC, LSW significantly inhibited colitis-associated tumorigenesis, reduced tumor number and tumor load (P < 0.05), obviously improved histopathological changes in the colon, downregulated the mRNA levels of proinflammatory cytokines, and inhibited the proliferation (P < 0.01) and promoted apoptosis of colon tumor cells (P < 0.001). LSW also significantly decreased TLR4 protein expression in the colon tissue (P < 0.05).

CONCLUSION

LSW can inhibit CAC in mice possibly by regulating the expression of TLR4 to reduce intestinal inflammation, inhibit colon tumor cell proliferation and promote their apoptosis.

Molecular Complexation of Polymers and Metal Oxide Clusters for Semicrystalline, Thermoplastic Anhydrous Proton Exchange Membranes in Fuel Cells

With the manipulation of surface charges and loadings, 1 nm super-acidic metal oxide clusters can co-crystallize with poly(ethylene glycol) (PEG) at molecular scale for thermoplastic anhydrous proton exchange membranes (PEMs). The coexistence of crystalline and amorphous regions endows the PEMs with a high Young's modulus and high flexibility, while the noncovalent complex interactions enable facile preparation and (re)processing. Furthermore, the diffusive dynamics of PEG chains is slowed by the confinement effect, while the local segmental dynamics is accelerated due to the transition of the chain conformation from helix to zigzag when confined in the crystalline framework. This greatly facilitates proton transportation in the crystalline region for an excellent anhydrous proton conductivity of 4.5 × 10^-3 S cm^-1 at 90 °C. The balanced proton conductivity, mechanical strength, and processability of the PEMs contribute to the promising power density of H₂/O₂ fuel cells assembled with co-crystalline PEMs at high temperatures under dry conditions.

Scalable synthesis of soluble crystalline ionic-graphdiyne by controlled ion expansion

Graphdiyne (GDY) is a promising material possessing extensive electronic tunability, high π conjugacy, and ordered porosity at a molecular level for the sp/sp2-hybridized periodic structures. Despite these advantages, the preparation of soluble and crystalline graphdiyne is limited by the relatively compact stacking interactions, mostly existing in thick-layer and insoluble solids. Herein, we proposed a strategy of "framework charge-induced intercalation (FCII)" for the synthesis of a soluble (4.3 mg ml-1) and yet interlayer-expanded (∼0.6 Å) crystalline ionic graphdiyne, named as N+-GDY, through regulating the interlayer interactions. The skeleton of such a sample is positively charged, and then the negative ions migrate to the interlayer to expand the space, endowing the N+-GDY with solution processability. The crystal structure of N+-GDY is proved through analysis of HR-TEM images under different axes of observation and theoretical simulations. The resulting N+-GDY possesses high dispersity in organic solvents to produce a pure-solution phase which is conducive to the formation of oriented N+-GDY films, accompanied by exfoliation-nanosheet restacking. The film exhibits a conductivity of 0.014 S m-1, enabling its applications in electronic devices.

Functional Molecular Granular Materials: Advances and Perspectives

Molecular granular materials (MGMs) are constructed with sub-nanoscale molecular clusters (MCs) as the building units and they have recently been observed to possess enriched functionalities distinct from granular materials of colloid nanoparticles. Herein, the birth and recent research advances in MGMs are summarized with the topics covering the precise synthesis of MC assemblies with target topologies, the hierarchical relaxation dynamics and tuneable viscoelasticity, impact-resistant capacity, and proton conductivity performance. The extremely small size of MC renders them two features: bulk diffusive dynamics with energy scale close to thermal fluctuation energy and the dominant volume fraction of surface structures. This finally leads to the hierarchical relaxation dynamics and broadly tuneable viscoelasticity of MGMs although the structural units are with small sizes and low M_w . Therefore, MGMs have been applied as impact resistant materials and proton conductors for the highly tuneable relaxation dynamics.

Supramolecular Assembly and Microscopic Dynamics Modulation of Nanoscale Inorganic Cryptand and Polymer Complex for Versatile Design of Flexible Single-Ion Conductors

The popular design of solid-state electrolytes (SSEs) from the chain relaxation of polymers faces the trade-offs among ion conductivity, stability, and processability. Herein, 2 nm inorganic cryptand molecules with the capability to carry different types of cations, including Ag⁺, Na⁺, K⁺, and Ca²⁺, are complexed with cationic polymers via ionic interaction, respectively, and the hybrid materials further phase separate into lamellar or hexagonal columnar structures. The successful establishment of ordered structures with ion channels from the packing of inorganic cryptands confers SSEs' excellent ionic conductivity to versatile types of cations. Meanwhile, suggested from the combination of broad dielectric spectroscopy, rheology, and thermal analysis, the fast chain relaxation can activate the dynamics of inorganic cryptand molecules and facilitate the ion hopping process in ion channels. The supramolecular interaction in the complex enables the highly flexible physical appearance for defect-free contact with electrodes as well as cost-effective processability and recyclability.

Metal oxide cluster-assisted assembly of anisotropic cellulose nanocrystal aerogels for balanced mechanical and thermal insulation properties

Cellulose nanocrystal (CNC) materials grant abundant possibilities for insulation, however, their extensive application is hindered by the intrinsic tradeoff between their thermal insulating performance and mechanical properties. Here, we show that CNC aerogels with balanced thermal and mechanical performance can be fabricated via a 1 nm metal oxide cluster (phosphotungstic acid, PTA)-assisted unidirectional freeze-drying processing. The as-prepared hybrid aerogels with hierarchical porous structures consisting of layer-by-layer CNC nanosheets enable the decoupling of the strengthening of mechanical properties and the enhancement of thermal insulating capabilities. Within layered structures, the surface-doped nanosized PTA clusters with negative charges behave as dynamic physical cross-linking points, and continuous networks of PTA-doped CNC can be formed via multiple supramolecular interactions (e.g., electrostatic attractions and hydrogen bonds). The afforded stable three-dimensional network structures are able to withstand externally applied forces and large deformations, endowing the aerogels with excellent mechanical performance. Moreover, the inter-layer gap is dominated by nanopores, endowing much lower thermal conductivities along the radial direction in comparison to the axial direction. The addition of PTA clusters also contributes to the obvious enhancements of the fire-retardant properties. Our discoveries provide a facile approach for the design and scalable production of CNC-based insulation materials with optimized mechanical properties and additional fire-retardant properties.

[Risk for type 2 diabetes mellitus death attributed to insufficient whole grain intake in seven regions of China, 2005-2018]

Objective: To estimate the risk for type 2 diabetes mellitus (T2DM) death attributed to insufficient whole grain intake in seven regions of China from 2005 to 2018. Methods: Based on China National Nutrition and Health Surveys and China Adult Chronic Disease and Nutrition Surveillance, ordinary Kriging method and locally weighted regression were used to estimate the level of whole grain intake of Chinese residents from 2005 to 2018. Based on the results of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 and Chronic Diseases Risk Factors Surveillance in China, we calculated the population attributable fraction (PAF), attributable death number and attributable mortality rate of T2DM due to insufficient whole grain intake in people aged ≥20 years in different regions of China, and we used the 2010 Chinese census data to compare the changes in T2DM deaths attributed to insufficient intake of whole grains in seven regions of China. Results: The whole grain intake levels of Chinese people over 20 years old in 2002, 2010 and 2015 were 19.0 g/d, 14.3 g/d and 19.8 g/d, respectively. The estimated overall whole grain intake level was 20.1 g/d in Chinese residents in 2018, and the intake level was 19.4 g/d in men and 20.8 g/d in women. Among the seven regions, the intake level was highest in northern China (47.4 g/d) and lowest in southwestern China (6.0 g/d). In 2018, the PAF was lowest in northern China (12.8%) and highest in southwestern China (19.3%). From 2005 to 2018, the PAF varied in the seven regions, and the PAF in northeastern China fluctuated around 18.5%. Other regions showed downward trends, especially in northern China and northwestern China, decreased by 26.4% and 21.2%, respectively. Over the past 14 years, the number of attributable deaths in the seven regions showed upward trends, with the highest annual average growth rate of 6.7% in southern China and the lowest annual average growth rate of 2.4% in northern China. In 2018, the standardized T2DM mortality rate attributed to insufficient whole grain intake in China was 3.13/100 000, and the attributable mortality was 3.21/100 000 in men and 3.05/100 000 in women. The standardized attributable mortality rate was highest in southwestern China (3.97/100 000) and lowest in northern China (1.78/100 000). From 2005 to 2018, the standardized attributable mortality rate increased by 11.5% in men and decreased by 8.1% in women. The standardized attributable mortality rate in southwestern, southern and central China increased by 23.7%, 21.3% and 4.2%, respectively. The standardized attributable mortality rate in northern, northwestern, eastern and northeastern China decreased by 20.9%, 11.0%, 4.5% and 3.9%, respectively. Conclusion: The whole grain intake level of Chinese residents was low, and the whole grain intake of residents in all seven regions should be increased, especially in the southwest, and men should have more whole grain intake than women to reduce the death risk in patients with T2DM.

[Burden of hemorrhagic stroke and hypertensive heart disease attributed to alcohol consumption in China]

Objective: To describe the prevalence of alcohol consumption and the burden of hemorrhagic stroke and hypertensive heart disease attributed to alcohol consumption in adults aged ≥20 years in 31 provinces in China from 2005 to 2018. Methods: Data from several national representative surveys was used to estimate provincial alcohol exposure level of adults aged ≥20 years from 2005 to 2018 by using kriging interpolation and locally weighted regression methods. Global disease burden research method and data, and China's death cause surveillance data were used to calculate the population attributable fraction (PAF) of hemorrhagic stroke and hypertensive heart disease and the deaths due to alcohol consumption in men and women aged ≥20 years in 31 provinces in China. China census data of 2010 were used to calculate the attributable standardized mortality rate. Results: In 2005 and 2018, the prevalence of alcohol consumption was 58.7% (95%CI: 57.8%-59.5%) and 58.4% (95%CI: 57.6%-59.3%), respectively, in men and 17.0% (95%CI: 16.6%-17.4%) and 18.7% (95%CI:18.1%-19.3%), respectively, in women. The daily alcohol intake was 24.6 (95%CI: 23.8-25.3) g and 27.7 (95%CI: 26.8-28.7) g, respectively, in men and 6.3 (95%CI: 6.0-6.5) g and 5.3 (95%CI: 5.0-5.6) g, respectively, in women. Alcohol exposure level was higher in the provinces in central and eastern China than in western provinces. The lowest exposure level was found in northwestern provinces. From 2005 to 2018, the PAF of hemorrhagic stroke death due to alcohol consumption increased from 5.5% to 6.8%, the attributable deaths increased from 50 200 to 59 100, while the PAF of hypertensive heart disease death due to alcohol consumption increased from 7.0% to 7.7%, the attributable deaths increased from 15 200 to 29 300. The PAF of hypertensive heart disease and hemorrhagic stroke was higher in men than in women, and in central and eastern provinces than in western provinces. In 2018, the standardized mortality rates of hemorrhagic stroke and hypertensive heart disease attributed to alcohol consumption were 4.58/100 000 and 2.11/100 000, respectively. Conclusions: The prevalence of alcohol consumption in men and daily alcohol intake of drinkers were relatively high in China, especially in eastern provinces. Alcohol exposure level was lower in women than in men. Regional measures should be taken to reduce the alcohol intakes in men and current drinkers in order to reduce the health problems caused by alcohol consumption.

Probing sub-5 Ångstrom micropores in carbon for precise light olefin/paraffin separation

Olefin/paraffin separation is an important but challenging and energy-intensive process in petrochemical industry. The realization of carbons with size-exclusion capability is highly desirable but rarely reported. Herein, we report polydopamine-derived carbons (PDA-Cx, where x refers to the pyrolysis temperature) with tailorable sub-5 Å micropore orifices together with larger microvoids by one-step pyrolysis. The sub-5 Å micropore orifices centered at 4.1-4.3 Å in PDA-C800 and 3.7-4.0 Å in PDA-C900 allow the entry of olefins while entirely excluding their paraffin counterparts, performing a precise cut-off to discriminate olefin/paraffin with sub-angstrom discrepancy. The larger voids enable high C₂H₄ and C₃H₆ capacities of 2.25 and 1.98 mmol g^-1 under ambient conditions, respectively. Breakthrough experiments confirm that a one-step adsorption-desorption process can obtain high-purity olefins. Inelastic neutron scattering further reveals the host-guest interaction of adsorbed C₂H₄ and C₃H₆ molecules in PDA-Cx. This study opens an avenue to exploit the sub-5 Å micropores in carbon and their desirable size-exclusion effect.

The Counterion-Mediated Controllable Coacervation of Nano-Ions with Polyelectrolytes

Nano-ions can complex with polyelectrolytes for coacervates with hierarchical structures; however, the rational design of functional coacervations is still rare due to the poor understanding of their structure-property relationship from their complex interaction. Herein, 1 nm anionic metal oxide clusters, PW₁₂O₄₀^3-, with well-defined, mono-disperse structures are applied to complex with cationic polyelectrolyte and the system shows tunable coacervation via the alternation of counterions (H⁺ and Na⁺) of PW₁₂O₄₀^3-. Suggested from Fourier transform infrared spectroscopy (FT-IR) and isothermal titration studies, the interaction between PW₁₂O₄₀^3- and cationic polyelectrolytes can be modulated by the bridging effect of counterions via hydrogen bonding or ion-dipole interaction to carbonyl groups of polyelectrolytes. The condensed structures of the complexed coacervates are explored by small angle X-ray and neutron scattering techniques, respectively. The coacervate with H⁺ as counterions shows both crystallized and discrete PW₁₂O₄₀^3- clusters, with a loose polymer-cluster network in comparison to the system of Na⁺ which shows a dense packing structure with aggregated nano-ions filling the meshes of polyelectrolyte networks. The bridging effect of counterions helps understand the super-chaotropic effect observed in nano-ion system and provides avenues for the design of metal oxide cluster-based functional coacervates.

Emergence of Visible-Light Water Oxidation Upon Hexaniobate-Ligand Entrapment of Quantum-Confined Copper-Oxide Cores

The formation of small 1 to 3 nm organic-ligand free metal-oxide nanocrystals (NCs) is essential to utilization of their attractive size-dependent properties in electronic devices and catalysis. We now report that hexaniobate cluster-anions, [Nb₆ O₁₉ ]^8- , can arrest the growth of metal-oxide NCs and stabilize them as water-soluble complexes. This is exemplified by formation of hexaniobate-complexed 2.4-nm monoclinic-phase CuO NCs (1), whose ca. 350 Cu-atom cores feature quantum-confinement effects that impart an unprecedented ability to catalyze visible-light water oxidation with no added photosensitizers or applied potentials, and at rates exceeding those of hematite NCs. The findings point to polyoxoniobate-ligand entrapment as a potentially general method for harnessing the size-dependent properties of very small semiconductor NCs as the cores of versatile, entirely-inorganic complexes.

Dynamics and Proton Conduction of Heterogeneously Confined Imidazole in Porous Coordination Polymers

The nanoconfinement of proton carrier molecules may contribute to the lowing of their proton dissociation energy. However, the free proton transportation does not occur as easily as in liquid due to the restricted molecular motion from surface attraction. To resolve the puzzle, herein, imidazole is confined in the channels of porous coordination polymers with tunable geometries, and their electric/structural relaxations are quantified. Imidazole confined in a square-shape channels exhibits dynamics heterogeneity of core-shell-cylinder model. The core and shell layer possess faster and slower structural dynamics, respectively, when compared to the bulk imidazole. The dimensions and geometry of the nanochannels play an important role in both the shielding of the blocking effect from attractive surfaces and the frustration filling of the internal proton carrier molecules, ultimately contributing to the fast dynamics and enhanced proton conductivity.

The Marriage of Sierpiński Triangles and Platonic Polyhedra

Fractal structures with self-similarity are of fundamental importance in the fields of aesthetic, chemistry and mathematics. Here, by taking advantage of constructs the rational geometry-directed precursor design, we report the construction of two fascinating Platonic solids, the Sierpiński tetrahedron ST-T and the Sierpiński octahedron ST-O, in which each possesses a fractal Sierpiński triangle on their independent faces. These two discrete complexes are formed in near-quantitative yield from the multi-component self-assembly of truncated Sierpiński triangular kernel L¹ with tribenzotriquinacene-based hexatopic and anthracene-based tetratopic terpyridine ligands (L³ and L⁴ ) in the presence of metal ions, respectively. The enhanced stabilities of the 3D discrete structures were investigated by gradient tandem mass spectrometry (gMS² ). This work provides new constructs for the imitation of complex virus assemblies and for the molecular encapsulation of giant guest molecules.

Decoupling Segmental Dynamics and Ionic Transport for Superionic Anhydrous Proton Conductors of Polyoxometalate-poly(ethylene glycol) Nanocomposites

Superionic anhydrous proton conductors can be obtained from the complexation of nanoscale polyoxometalates (POMs) and poly(ethylene glycol) (PEG) in the "polymer in salt" regime. The reduced energy barrier of H⁺ hopping is facilitated from the increased H⁺ concentration and shortened inter-POM distances. POMs with identical structure/size (≈1 nm) but different charge densities are complexed with PEG, respectively, with concentrations ranging from 10 to 60 % wt. Increasing trends of viscosities can be observed with the rising charge densities of POMs due to the increasing confinement strength on PEG substrate from POMs. Fractional Walden rule is further applied to analyze the viscosity and proton conductivity correlations, and microscopic mechanisms of proton conduction for PEG-POM nanocomposites are revealed: 1) ion transport is highly associated with polymer chain dynamic for POMs concentrations ranging from 10 to 30 % wt.; 2) ionic conduction is largely decoupled from chain dynamic of polymer matrix for concentrations ranging from 40 to 60 % wt. with Walden plots shifted to the superionic regime. The decoupling of proton transport from polymer segment dynamics allows the simultaneous enhancements of the nanocomposites' mechanical properties and proton conductions, providing guidelines for the rational design of anhydrous proton conductors with integrated functionalities.