Trade-offs between ion-conducting and mechanical properties: The case of polyacrylate electrolytes

Polymer electrolytes(PEs)have been long recognized as the key materials to enable energy-dense batteries and render flexible energy devices practically viable,owing to their chemical and mechanical reliability.However,much of their promise is yet to be realized.The roomtemperature ion conductivity of existing PEs still falls short of the implementation criterion of 10^(-4) S cm^(-1) on the promise of acceptable mechanical properties,thereby precluding their practical application.The twin but inversely related duties of polymers,that is,functioning as both an ion-conducting medium and a structural backbone,underlie this issue but are less elucidated systematically.The polyacrylate(PA)family is among promising polymer matrices on account of ester polarity,electrode compatibility,chemical tunability,and mechanical durability.The extensive applicability of PA in plasticized gels,dry solids,and emerging composites makes PA-based PEs representative to illustrate the trade-off between ion conduction and mechanical strength.We herein seek to outline the stated long-standing conflict exemplified by PA-based PEs,focusing on crucial strategies toward balancing and reconciling the two mutually exclusive properties,with the intention of offering designing guidelines for next-generation PEs.

Towards a multiscale model of colorectal cancer

Colorectal cancer (CRC) is one of the best characterised cancers, with extensive data documenting the sequential gene mutations that underlie its development. Complementary datasets are also being generated describing changes in protein and RNA expression, tumour biology and clinical outcome. Both the quantity and the variety of information are inexorably increasing and there is now an accompanying need to integrate these highly disparate datasets. In this article we aim to explain why we believe that mathematical modelling represents a natural tool or language with which to integrate these data and, in so doing, to provide insight into CRC.

Laser-induced fluorescence experimental spectroscopy and theoretical calculations of uranium monoxide

As a model molecule of actinide chemistry,UO molecule plays an important role in understanding the electronic structure and chemical bonding of actinide-containing species.We report a study of the laser-induced fluorescence spectra of the U^(16)O and U^(18)O using two-dimensional spectroscopy.Several rotationally resolved excitation spectra were investigated.Accurate molecular rotational constants and equilibrium internuclear distances were reported.Low-lying electronic states information was extracted from high resolution dispersed fluorescence spectra and analyzed by the ligand field theory model.The configuration of the ground state was determined as U^(2+)(5 f^(3)7 s)O^(2-).The branching ratios,and the vibrational harmonic and anharmonic parameters were also obtained.Radiative lifetimes were determined by recording the timeresolved fluorescence spectroscopy.Transition dipole moments were calculated using the branching ratios and the radiative lifetimes.These findings were elucidated by using quantum-chemical calculations,and the chemical bonding was also analyzed.The findings presented in this work will enrich our understanding of actinide-containing molecules.

Synthesis and photophysical properties of donor–acceptor system based bipyridylporphyrins for dye-sensitized solar cells

Bipyridylporphyrin derivatives possessing a porphyrin moiety as the electron donor and bipyridyl moiety as the electron-acceptor were designed and synthesized for dye-sensitized solar cells （DSSCs）. The photo- physical and electrochemical properties were investigated by absorption spectrometry and cyclic voltam- metry. Density functional theory （DFT） was employed to study electron distribution. From the photovoltaic performance measurements, a maximum conversion efficiency （η） of 0.38% was achieved based on the bipyridylporphyrin ruthenium dye A7 （Jsc = 1.33 mA/cm^2, Voc = 0.45 V, FF = 0.64） under 1,5 irradiation （100 mW/cm^2）.

Quantitative understanding of phase segregation behaviors by precisely building discrete oligo-ester-b-oligo-olefin block copolymers

Block copolymers(BCPs) with high Flory-Huggins parameter(χ) and balanced surface energy have aroused tremendous interest for ultra-small nanopatterns processing.However,high χ and balanced surface energy are generally contradicted.The fine tune of chain structure might be a useful way to achieve high χ and balanced surface energy.To realize this,the block copolymer with exactly uniform chain structure,i.e.,defined molecular structure,is highly desirable for accurately evaluating the phase behavior.Herein,two kinds of discrete oligo ester-b-oligo olefin block copolymers with different chemical structures(oligo lactic acid-boligo olefin BCP,oLA_(n)-b-C_(m);oligo phenyl lactic acid-b-oligo olefin BCP,oPL_(n)-b-C_(m)) were modularly synthesized through iterative growth methods.The effect of chain structure on segregation strength and surface properties was quantitatively investigated using the discrete BCPs as precise models.On the one hand,introducing rigid and nonpolar phenyl groups into oligo ester block has a negligible effect on the chemical incompatibility,as confirmed by the identical high χ values of oLA_(n)-b-C_(m) and oPL_(n)-b-C_(m)(χ_(oLA/C)=0.21 and χ_(oPL/C)=0.19).On the other hand,the incorporation of nonpolar phenyl groups creates balanced surface energy,that is,the high χ and balanced surface energy were simultaneously achieved by oPL_(n)-b-C_(m).Therefore,sub-10 nm perpendicular nanopatterns can be easily produced upon brief thermal treatment,demonstrating its potential application in semiconductor manufacturing with ultra-small feature size.The discrete BCP can serve as a quantitative and exquisite model to study the critical contribution of chain structures on phase separation behavior,providing insightful understanding to facilitate the potential application in the chip process.

Cirrhotic portal hypertension: From pathophysiology to novel therapeutics

Portal hypertension and bleeding from gastroesophageal varices is the major cause of morbidity and mortality in patients with cirrhosis. Portal hypertension is initiated by increased intrahepatic vascular resistance and a hyperdynamic circulatory state. The latter is characterized by a high cardiac output, increased total blood volume and splanchnic vasodilatation, resulting in increased mesenteric blood flow. Pharmacological manipulation of cirrhotic portal hypertension targets both the splanchnic and hepatic vascular beds. Drugs such as angiotensin converting enzyme inhibitors and angiotensin Ⅱ type receptor 1 blockers, which target the components of the classical renin angiotensin system(RAS), are expected to reduce intrahepatic vascular tone by reducing extracellular matrix deposition and vasoactivity of contractile cells and thereby improve portal hypertension. However, these drugs have been shown to produce significant offtarget effects such as systemic hypotension and renal failure. Therefore, the current pharmacological mainstay in clinical practice to prevent variceal bleeding and improving patient survival by reducing portal pressure is non-selective-blockers(NSBBs). These NSBBs work by reducing cardiac output and splanchnic vasodilatation but most patients do not achieve an optimal therapeutic response and a significant proportion of patients are unable to tolerate these drugs.Although statins, used alone or in combination with NSBBs, have been shown to improve portal pressure and overall mortality in cirrhotic patients, further randomized clinical trials are warranted involving larger patient populations with clear clinical end points. On the other hand, recent findings from studies that have investigated the potential use of the blockers of the components of the alternate RAS provided compelling evidence that could lead to the development of drugs targeting the splanchnic vascular bed to inhibit splanchnic vasodilatation in portal hypertension. This review outlines the mechanisms related to the pathogenesis of portal hypertension and attempts to provide an update on currently available therapeutic approaches in the management of portal hypertension with special emphasis on how the alternate RAS could be manipulated in our search for development of safe, specific and effective novel therapies to treat portal hypertension in cirrhosis.

Hydration reactivity difference between dicalcium silicate and tricalcium silicate revealed from structural and Bader charge analysis

Cement hydration is the underlying mechanism for the strength development in cement-based materials.The structural and electronic properties of calcium silicates should be elucidated to reveal their difference in hydration reactivity.Here,we comprehensively comparedβ-C_(2)S and M_(3)-C_(3)S and investigated their structural properties and Bader charge in the unit cell,during surface reconstruction and after single water adsorption via density functional theory.We identified different types of atoms inβ-C_(2)S and M_(3)-C_(3)S by considering the bonding characteristics and Bader charge.We then divided the atoms into the following groups:forβ-C_(2)S,Ca and O atoms divided into two and four groups,respectively;for M_(3)-C_(3)S,Ca,O,and Si atoms divided into four,four,and three groups,respectively.Results revealed that the valence electron distribution on the surface was more uniform than that on the unit cell,indicating that some atoms became more reactive after surface relaxation.During water adsorption,the electrons ofβ-C_(2)S and M_(3)-C_(3)S were transferred from the surface to the adsorbed water molecules through position redistribution and bond formation/breaking.On this basis,we explained whyβ-C_(2)S and M_(3)-C_(3)S had activity differences.A type of O atom with special bond characteristics(no O–Si bonds)and high reactivity existed in the unit cell of M_(3)-C_(3)S.Bader charge analysis showed that the reactivity of Ca and O atoms was generally higher in M_(3)-C_(3)S than inβ-C_(2)S.Ca/O atoms had average valence electron numbers of6.437/7.550 inβ-C_(2)S and 6.481/7.537 in M_(3)-C_(3)S.Moreover,the number of electrons gained by water molecules in M_(3)-C_(3)S at the surface was higher than that inβ-C_(2)S.The average variations in the valence electrons of H_(2)O onβ-C_(2)S and M_(3)-C_(3)S were 0.041 and 0.226,respectively.This study further explains the differences in the hydration reactivity of calcium silicates and would be also useful for the design of highly reactive and environmentally friendly cements.

Caspase-cleaved cytokeratin-18 and tumour regression in gastro-oesophageal adenocarcinomas treated with neoadjuvant chemotherapy

AIM:To examine cytokeratin-18(CK-18) and caspasecleaved CK-18 expression in tumours and correlate with clinicopathological outcomes including tumour regression grade(TRG) response.METHODS:Formalin-fixed human gastro-oesophageal cancers were constructed into tissue microarrays.The first set consisted of 122 gastric/gastro-oesophageal cancer cases not exposed to neoadjuvant chemotherapy and the second set consisted of 97 gastric/gastrooesophageal cancer cases exposed to pre-operative platinum-based chemotherapy.Expression of CK-18 and caspase-cleaved CK-18 was investigated using immunohistochemistry.RESULTS:CK18 was commonly expressed in gastrooesophageal tumours(92.6%).Fifty-six point seven percent of tumours previously exposed to neoadjuvant chemotherapy were positive for caspase-cleaved CK-18 expression compared to only 24.6% of tumours not previously exposed to neoadjuvant chemotherapy(P = 0.009).In patients who received neoadjuvant chemotherapy,caspase-cleaved cytokeratin-18 expression correlated with favourable TRG response(TRG 1,2 or 3,P = 0.043).CONCLUSION:This is the largest study to date of CK-18 and caspase-cleaved CK-18 expression in gastrooesophageal tumours.We provide the first evidence that caspase-cleaved CK-18 predicts tumour regression with neoadjuvant chemotherapy.

Spherical Packing Superlattices in Self-Assembly of Homogenous Soft Matter:Progresses and Potentials

The construction of complex superlattices using homogenous soft matter has great potential for the bottom-up fabrication of complex,nanoscale structures.This topic is not only interested in scientific exploring for new concepts of supramolecular crystals with nanometer in sizes,which is about thousand times larger in volumes than those of normal crystals,but also practically important to provide construction principles of metamaterials which are artificially structured materials for controlling and manipulating light,sound,and other physical behaviors.These systems have fast assembly kinetics and convenient processing procedures,making them ideal for large-scale superlattice production.In this perspective,we focus on recent developments in the construction of complex spherical packing superlattices using homogenous soft self-assemblies.We discuss the general mechanism of those formations of supramolecular motifs and provide an overview of the spherical packing superlattices self-assembled by homogenous soft matters based on different volume asymmetry.Additionally,we outline the potentials of utilizing this approach in constructing novel superlattices as well as its future challenges.

Optimization on transport of charge carriers in cathode of sulfide electrolyte-based solid-state lithium-sulfur batteries

Lithium-sulfur(Li-S)batteries are considered as promising candidates for novel energy storage technology that achieves energy density of 500 Wh·kg^(−1).However,poor cycle stability resulting from notorious shuttle effect and the safety concerns deriving from flammability of ether-based electrolyte hinder the practical application of Li-S batteries.Because of low solubility to polysulfide,high ionic conductivity,and safety property,sulfide-based electrolytes can fundamentally address above issues.It is widely known that the effective transports of both electrons and ions are basic requirement for redox reaction of active materials in cathode.Thereby,construction of fast and stable ionic and electronic transport paths in cathode is especially pivotal for cycle stability of solid-state Li-S batteries(SSLSBs).In this review,we provide research progresses on facilitating transport of charge carriers in composite cathode of SSLSBs.From perspective of materials,intrinsically conductivity of electrolyte and carbon shows dramatic effect on migration of charge carriers in cathode of SSLSBs,thereby the conductive additives are summarized in the manuscript.Additionally,the charge transport in cathode of SSLSBs fully depends on the physical contact between active materials and conductive additives,therefore we summarized the strategies optimizing interfacial contact and reducing interfacial resistance.Finally,potential future research directions and prospects for SSLSBs with improved energy density and cycle performance are also proposed.

Design of Polymers for Intracellular Protein and Peptide Delivery

Cytosolic protein delivery techniques are of great importance for cell biology,biotechnology and protein drug development.The design of carriers with robust efficiency in cytosolic protein delivery is challenging.This account provides a progress report of polymeric carriers for this purpose in our group.During the past years,we have developed several types of functionalized polymers for cytosolic protein and peptide delivery by engineering polymers with ligands such as guanidinium,boronate,coordination ligands and fluoroalkyls.The designed polymers showed improved protein/peptide binding affinities,and successfully delivered various cargo proteins into the cytosol of living cells,while maintaining their bioactivity.In addition,the polymers showed potent efficiencies in the delivery of tumor antigens,therapeutic peptides,toxins and antioxidant proteins in vivo.We hope these polymers could be translated for protein delivery in the treatment of various diseases in the future.

A polymeric co-assembly of subunit vaccine with polyoxometalates induces enhanced immune responses

Long-lasting protective immune responses are expected following vaccination.However,most vaccines alone are inability to evoke an efficient protection.The combinatory administration of adjuvants with vaccines is critical for generating the enhanced immune responses.Herein,with biocompatible poly(4-vinylpyridine)(P4VP)as template,2.5 nm iron/molybdenum oxide cluster,{Mo_(72)Fe_(30)},is applied as an adjuvant to co-assemble with antigens of Mycobacterium bovis via hydrogen bonding at molecular scale.Molecular scale integration of the antigens and{Mo_(72)Fe_(30)}and their full exposure to body fluid media contribute to the augmentation of both humoral and cellular immune responses of the vaccines after inoculation in mice.Anti-inflammatory factor IL-10 gradually increases after 2 weeks followed by a final back to normal level by the 5th week.The balance between proinflammatory cytokines and anti-inflammatory factors suggests that immune system can be activated in the early stage of infection by the antigens carried by the supra-particles and secrete acute inflammatory factors for host defense and anti-inflammatory factors for immune protection.

Polymerization-induced microphase separation of polymer-polyoxometalate nanocomposites for anhydrous solid state electrolytes

Solid-state electrolytes(SSEs)with high ionic conductivity,mechanical stability,and high thermal stability,as well as the stringent requirement of application in high-temperature fuel cells and lithium-ion batteries is receiving increasing attention.Polymer nanocomposites(PNCs),combining the advantages of inorganic materials with those of polymeric materials,offer numerous opportunities for SSEs design.In this work,we report a facile and general one-pot approach based on polymerization-induced microphase separation(PIMS)to generate PNCs with bi-continuous microphases.This synthetic strategy transforms a homogeneous liquid precursor consisting of polyoxometalates(POMs,H_(3)PW_(12)O_(40),Li_(7)[V_(15)O_(36)(CO_(3))]),poly(ethylene glycol)(PEG)macro-chain-transfer agent,styrene and divinylbenzene monomers,into a robust and transparent monolith.The resulting POMs are uniformly dispersed in the PEG block(PEG/POM)to form a conducting pathway that successfully realizes the effective transfer of protons and lithium ions,while the highly cross-linked polystyrene domains(P(S-co-DVB))as mechanical support provide outstanding mechanical properties and thermal stability.As the POM loading ratio up to 35 wt%,the proton conductivity of nanocomposite reaches as high as 5.99×10^(-4) S/cm at 100℃ in anhydrous environment,which effectively promotes proton transfer under extreme environments.This study broadens the application of fuel cells and lithium-ion batteries in extreme environments.

Spoilt for Choice:New Options for Inhibitors of Strigolactone Signaling

Endogenously synthesized plant hormones direct the ordered growth of tissues,organs,and the overall plant body plan, thereby integrating external information with internal metabolism. Because plant hormones can have such dramatic and systemic effects on plant morphology,hormone activity has been a target of selective breeding for desirable plant traits,whether consciously or otherwise.

Local Conformational Constraint of Firefly Luciferase Can Affect the Energy of Bioluminescence and Enzyme Stability

Conformational dynamics contribute importantly to enzyme catalysis,such that targeted conformational constraint may affect catalysis.Firefly luciferases undergo extensive structural change during catalysis;key residues form a hydrophobic pocket,excluding water and enabling maximally energetic light production.Point mutants almost always luminesce at longer wavelengths(lower energy)than the wild type.Conformational constraint,using dipeptide analogue 3 at a position critical for optimized excited state structure,produced luciferase emission at a shorter wavelength by∼10 nm.Incomparison,introduction of conformationally constrained analogues 4,5,or 7 afforded luciferases emitting at longer wavelengths,while a related unconstrained luciferase(analogue 6)exhibited wild-type emission.The constrained luciferases tested were more stable than the wild type.Protein modeling demonstrated that the“inside”or“outside”orientation of the conformationally constrained dipeptide led to the shorter or longer emission wavelength,respectively.More broadly,these results suggest that local conformational constraint can control specific elements of enzyme behavior,both in vitro and in vivo.This represents the first example of studying enzyme function by introducing conformationally constrained dipeptides at a specific protein position.The principles discovered here in luciferase modification will enable studies to control the wavelength emission and photophysical properties of modified luciferases.

The importance of the bite angle of metal(Ⅲ) salen catalysts in the sequestration of CO_(2) with epoxides in mild conditions

Located in the middle of the fever to solve the problem of CO_(2)emissions in the environment,CO_(2)sequestration by reaction with epoxides is one of the key tools,as it not only fixes CO_(2),but also makes it functional by leading to cyclic carbonates.Herein,the results are focused specifically on the formation of cyclic organic carbonates catalyzed by metal-salen complexes,previously achieved with yttrium and scandium,that are compared with those of analogous complexes containing metals from the first transition series,such as cobalt or chromium.Density functional theory(DFT)calculations allow to determine whether this switch of metals will be feasible and provide the basis for instigating future experimental efforts in this regard.The calculations analyzing the structure and electronics of the catalysts allow us to give not only a clear picture of whether these catalysts will be efficient,but also allow us to assess which metal center is the most convenient and/or whether the catalytic reaction will occur under mild conditions.Advanced buried volume calculations with the SambVca packages shed light on the different catalytic pockets of monometallic first row transition metals vs.group III salen complexes.Our predictive catalysis results show that the bite O-M-O angle plays an essential role in the catalysis.

Surface science approach to the heterogeneous cycloaddition of CO_(2) to epoxides catalyzed by site-isolated metal complexes and single atoms: a review

The cycloaddition of CO_(2) to epoxides to afford cyclic organic carbonates is an increasingly relevant non-reductive strategy to convert CO_(2) to useful products able to serve as high-boiling solvents,chemical intermediates,and monomers for the preparation of more sustainable polymers.The development of efficient and robust hetero-geneous catalysts for such transformation is,therefore,crucial and can be carried out by several strategies that often require the preparation of sophisticated and/or expensive organic networks,linkers,or compounds.A different approach to the preparation of heterogeneous catalysts for CO_(2)-epoxide coupling is by applying surface science methodologies to graft molecular fragments or single atoms on various supports leading to well-defined active sites.In this context,surface organometallic chemistry(SOMC),along with comparable methodologies,is a valuable approach for the preparation of efficient,single-site Lewis acids and catalysts for the target cycloaddition reaction on metal oxides,whereas,other grafting methodologies,can be applied to prepare analogous catalysts on different kinds of surfaces.Finally,we discuss very recent advances in the application of surface methodologies for the preparation of single atom catalysts as an increasingly relevant approach towards highly active Lewis acids for the cycloaddition of CO_(2) to epoxides.Overall,we show that Lewis acids and catalysts prepared by facile surface methodologies hold significant potential for future application is the synthesis of cyclic carbonates from CO_(2).

Synthesis and EL Properties of Conjugated Copolymer Materials Containing Various Comonomers

1 Results Polymeric light-emitting diodes (PLEDs) have attracted much scientific and technological research interest due to a number of advantages over inorganic or organic small molecules for use in LEDs: better processability,lower operating voltages,faster response times,lower production costs,and high flexibility.Polyfluorene has been selected for the polymer backbone,because of its large band gap,facile substitution at the C9 position of fluorene,good chemical and thermal stability,and high photolu...

Dual Effects of Interfacial Interaction and Geometric Constraints on Structural Formation of Poly(butylene terephthalate)Nanorods

When the size of the material is smaller than the size of the molecular chain,new nanostructures can be formed by crystallizing polymers in nanoporous alumina.However,the effect of pore wall and geometric constraints on polymer nanostructures remains unclear.In this study,we demonstrate three new restricted nanostructures{upright-,flat-and tilting-ring}in polybutylene terephthalate(PBT)nanorods prepared from nanoporous alumina.The dual effects of geometrical constraints and interfacial interactions on the formation of PBT nanostructures were investigated for the first time by using X-ray diffraction and Cerius^(2) modeling packages.Under weak constraints,the interaction between pore wall and the PBT rings is dominant and the ring plane tends to be parallel to the pore wall and radiate outward to grow the upright-ring crystals.Surprisingly,in strong 2D confinement,a structural formation reversal occurs and geometrical constraints overpower the effect of pore wall.Rings tend to pile up vertically or obliquely along the long axis of the rod,so the flat-and tilting-ring crystals are predominate in the constrained system.In principle,our study of the nanostructure formation based on the geometrical constraints and the pore wall interfacial effects could provide a new route to manipulate the chain assembly at the nanoscale,further improving the performance of polymer nanomaterial.

Synthesis and Characterization of Fluorene-based Polymers Containing Electron-withdrawing Thiazolo Thiazole Unit

1 Results Low bandgap polymers can be used for pure red light emitting materials or solar cell materials.To make low bandgap polymers,we designed conjugated polymers with alternating sequences of the appropriate donor/acceptor units in the main chain.3-hexyl thiophene was used as a electron donating unit.For the electron accepting unit,we selected thiazolothiazole and bithiazole units having electron withdrawing property.Polyfluorene(PF) is the preferred conjugated polymer in light-emitting applications...