Intrinsic Polarity Research Articles

Strategic Design of Anion-Responsive Triarylboranes Exhibiting Colorimetric and Fluorometric Red-Shift for Sensing and Optoelectronic Applications.

Triarylboranes (TABs) have been employed as colorimetric and/or fluorometric anion sensors. The majority of TAB-based anion sensors exhibit blue-shift modes of absorption and photoluminescence (PL) or turn off of PL, attributed to the intrinsic electronic polarity of the trivalent boron unit in their molecular designs. In this Concept article, we introduce a novel approach to modulating the photophysical properties of TABs toward a red-shift mode by balancing the dual, opposing roles of the amine-bridged TAB (phenazaborine). This molecular design strategy enables significant changes in color and emission response to anions, shifting to the lower energy regime in solution. Additionally, this approach is applicable to the solid-state modulation of PL in films and organic light-emitting diodes (OLEDs).

Upcycling PVC and PET as Volume-Enhancing Functional Fillers for the Development of High-Performance Bio-Based Rigid Polyurethane Foams

Polyvinyl chloride (PVC) and polyethylene terephthalate (PET) contribute significantly to global plastic waste, with only 9% recycled in recent years. In this work, these plastic wastes were upcycled as functional fillers to improve the rigid polyurethane foam (RPUF) properties. To attain this target, we leveraged the intrinsic polarity of the C=O and C-Cl groups of PVC and PET to induce intermolecular attractions with the N-H groups of the polyurethane matrix, evidenced by the observed IR peak shifts. This enhanced the nucleating effect during foaming, increasing the foams’ compressive strengths by 77% and 22% with the addition of 10% PVC and 5% PET filler, respectively. Furthermore, the addition of PVC and PET fillers increased the foam volume. Thus, the collective utilization of PPW and its corresponding impact on the CO-based RPUF’s properties signifies a reduction in carbon dioxide emissions by 14.15% and 17.52% for PVC and PET, respectively. Moreover, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) revealed improved thermal stability and degradation profiles of the produced RPUFs. Overall, this work highlights potential advancement in environmentally responsible upcycling strategies for common end-of-life plastic wastes, while enhancing rigid foam properties.

Realization of Two-Dimensional Intrinsic Polar Metal in a Buckled Honeycomb Binary Lattice.

Structural topology and symmetry of a two-dimensional (2D) network play pivotal roles in defining its electrical properties and functionalities. Here, a binary buckled honeycomb lattice with C3v symmetry, which naturally hosts topological Dirac fermions and out-of-plane polarity, is proposed. It is successfully achieved in a group IV-V compound, namely monolayer SiP epitaxially grown on Ag(111) surface. Combining first-principles calculations with angle-resolved photoemission spectroscopy, the degeneration of the Dirac nodal lines to points due to the broken horizonal mirror symmetry is elucidated. More interesting, the SiP monolayer manifests metallic nature, which is mutually exclusive with polarity in conventional materials. It is further found that the out-of-plane polarity is strongly suppressed by the metallic substrate. This study not only represents a breakthrough of realizing intrinsic polarity in 2D metallic material via ingenious design but also provides a comprehensive understanding of the intricate interplay of many exotic low-dimensional quantum phenomena.

Electrochemical meta-C–H sulfonylation of pyridines with nucleophilic sulfinates

Considering the indispensable significance and utilities of meta-substituted pyridines in medicinal, chemical as well as materials science, a direct meta-selective C–H functionalization of pyridines is of paramount importance, but such reactions remain limited and highly challenging. In general, established methods for meta C–H functionalization of pyridines rely on the utilization of tailored electrophilic reagents to realize the intrinsic polarity match. Herein, we report a complementary electrochemical methodology; diverse nucleophilic sulfinates allow meta-sulfonylation of pyridines through a redox-neutral dearomatization-rearomatization strategy by a tandem dearomative cycloaddition/hydrogen-evolution electrooxidative C–H sulfonation of the resulting oxazino-pyridines/acid-promoted rearomatization sequence. Besides, several salient features, including exclusive regiocontrol, remarkable substrate/functional group compatibility, scale-up potential, and facile late-stage modification, have been demonstrated, which further contributes to the practicality and adaptability of this approach.

Intrinsic polarity extend β-Ga2O3/Janus-XP (X=P, As) heterostructures potential in UV/IR dual-band photodetector: A theoretical study

Although β-Ga2O3/black phosphorus (α-BP) has been employed to realize ultraviolet and infrared (UV/IR) dual-band photodetector, how to employ intrinsic polarity to improve the optoelectronic properties of β-Ga2O3/α-BP heterostructure further has not been demonstrated yet. Here, by investigating the interfacial electronic and optical properties of β-Ga2O3/Janus-XP (X=P, As) heterostructures with intrinsic polarity, we found that all β-Ga2O3/Janus-XP heterostructures exhibit type-II band alignment, regardless of the direction of intrinsic polarity. Moreover, β-Ga2O3/Janus-AsP heterostructures with intrinsic polarity possess stronger stability, more effective charge transfer with a lower tunneling barrier, and better UV/IR dual-band optical detection, which could be further improved when the direction of intrinsic polarity points away from the interface. The underlying mechanism is the extra carriers driving force introduced by intrinsic polarity. Our findings provide a deep understanding of β-Ga2O3/Janus-XP heterostructures and suggest an effective way to design high-performance β-Ga2O3 UV/IR dual-band photodetectors.

Nonreciprocal collective dynamics in a mixture of phoretic Janus colloids

A multicomponent mixture of Janus colloids with distinct catalytic coats and phoretic mobilities is a promising theoretical system to explore the collective behavior arising from nonreciprocal interactions. An active colloid produces (or consumes) chemicals, self-propels, drifts along chemical gradients, and rotates its intrinsic polarity to align with a gradient. As a result the connection from microscopics to continuum theories through coarse-graining couples densities and polarization fields in unique ways. Focusing on a binary mixture, we show that these couplings render the unpatterned reference state unstable to small perturbations through a variety of instabilities including oscillatory ones which arise on crossing an exceptional point or through a Hopf bifurcation. For fast relaxation of the polar fields, they can be eliminated in favor of the density fields to obtain a microscopic realization of the Nonreciprocal Cahn–Hilliard model for two conserved species with two distinct sources of non-reciprocity, one in the interaction coefficient and the other in the interfacial tension. Our work establishes Janus colloids as a versatile model for a bottom-up approach to both scalar and polar active mixtures.

Hyperexpression of tumor necrosis factor receptor 2 inhibits differentiation of myeloid-derived suppressor cells by instigating apolarity during ageing.

During the ageing process, TNF-α can promote the expansion of myeloid-derived suppressor cells (MDSCs). However, it remains unclear which receptor(s) of TNF-α are involved in and how they modulate this process. Here, we report that TNFR2 hyperexpression induced by either TNF-α or IL-6, two proinflammatory factors of senescence-associated secretory phenotype (SASP), causes cellular apolarity and differentiation inhibition in aged MDSCs. Ex vivo overexpression of TNFR2 in young MDSCs inhibited their polarity and differentiation, whereas in vivo depletion of Tnfr2 in aged MDSCs promotes their differentiation. Consequently, the age-dependent increase of TNFR2 versus unaltered TNFR1 expression in aged MDSCs significantly shifts the balance of TNF-α signaling toward the TNFR2-JNK axis, which accounts for JNK-induced impairment of cell polarity and differentiation failure of aged MDSCs. Consistently, inhibiting JNK attenuates apolarity and partially restores the differentiation capacity of aged MDSCs, suggesting that upregulated TNFR2/JNK signaling is a key factor limiting MDSC differentiation during organismal ageing. Therefore, abnormal hyperexpression of TNFR2 represents a general mechanism by which extrinsic SASP signals disrupt intrinsic cell polarity behavior, thereby arresting mature differentiation of MDSCs with ageing, suggesting that TNFR2 could be a potential therapeutic target for intervention of ageing through rejuvenation of aged MDSCs.

Local Mechanical Modulation-Driven Evagination in Invaginated Epithelia.

Local cells can actively create reverse bending (evagination) in invaginated epithelia, which plays a crucial role in the formation of elaborate organisms. However, the precise physical mechanism driving the evagination remains elusive. Here, we present a three-dimensional vertex model, incorporating the intrinsic cell polarity, to explore the complex morphogenesis induced by local mechanical modulations. We find that invaginated tissues can spontaneously generate local reverse bending due to the shift of the apicobasal polarity. Their exact shapes can be analytically determined by the local apicobasal differential tension and the internal stress. Our continuum theory exhibits three regions in a phase diagram controlled by these two parameters, showing curvature transitions from ordered to disordered states. Additionally, we delve into epithelial curvature transition induced by the nucleus repositioning, revealing its active contribution to the apicobasal force generation. The uncovered mechanical principles could potentially guide more studies on epithelial folding in diverse systems.

Bioinformatics Characteristics and Genomic Patterns of the Envelope Glycoproteins of the Crimean-congo Hemorrhagic Fever Viruses

Background: Rodents and many wild and domestic animals, including cattle, donkeys, goats, hares, ostriches, and sheep, spread the Crimean-Congo Hemorrhagic Fever Virus (CCHFV), acting as hosts for infected ticks primarily of the Hyalomma genus, which serve as vectors and reservoirs of the virus. CCHF is a severe, potentially lethal, and widespread disease, making it a serious public health issue. Environmental changes impacting rodent populations affect their global distribution and, therefore, play a role in the spread of CCHFV. Objective: This study aims togain a deeper understanding of the envelope glycoproteins expressed by the CCHFV. Methods: Multiple computational algorithms determined the Intrinsic Disorder Predisposition (PIDP), Polarity Index, and genomic profiles of each sequence of the glycoproteins. Results: When examining the Polarity Index Method Profile, 3.0v profile, and the PIDP profile, the envelope glycoproteins of the CCHFV showed different patterns. With these patterns, it was possible to identify structural and morphological similarities. Conclusion: With the PIM 3.0v profile, our computer programs were able to identify isolated CCHFV envelope glycoproteins. We believe that this research provides a deeper understanding of this virus. conclusion: Using the PIM 3.0v profile, our computer programs were able to identify isolates of the CCHFV envelope glycoproteins. We believe that this research contributes to a deeper understanding of this emerging virus.

Reversal of the Regioselectivity of Iron-Promoted Hydrogenation and Hydrohalogenation of gem-Difluoroalkenes.

The reaction regioselectivity of gem-difluoroalkenes is dependent on the intrinsic polarity. Thus, the reversal of the regioselectivity of the addition reaction of gem-difluoroalkenes remains a formidable challenge. Herein, we described an unprecedented reversal of regioselectivity of hydrogen atom transfer (HAT) to gem-difluoroalkenes triggered by Fe-H species for the formation of difluoroalkyl radicals. Hydrogenation of the in situ generated radicals gave difluoromethylated products. Mechanism experiments and theoretical studies revealed that the kinetic effect of the irreversible HAT process resulted in the reversal of the regioselectivity of this scenario, leading to the formation of a less stable α-difluoroalkyl radical regioisomer. On basis of this new reaction of gem-difluoroalkene, the iron-promoted hydrohalogenation of gem-difluoroalkenes for the efficient synthesis of aliphatic chlorodifluoromethyl-, bromodifluoromethyl- and iododifluoromethyl-containing compounds was developed. Particularly, this novel hydrohalogenation of gem-difluoroalkenes provided an effect and large-scale access to various iododifluoromethylated compounds of high value for synthetic application.

Reversal of the Regioselectivity of Iron‐Promoted Hydrogenation and Hydrohalogenation of gem‐Difluoroalkenes

AbstractThe reaction regioselectivity of gem‐difluoroalkenes is dependent on the intrinsic polarity. Thus, the reversal of the regioselectivity of the addition reaction of gem‐difluoroalkenes remains a formidable challenge. Herein, we described an unprecedented reversal of regioselectivity of hydrogen atom transfer (HAT) to gem‐difluoroalkenes triggered by Fe−H species for the formation of difluoroalkyl radicals. Hydrogenation of the in situ generated radicals gave difluoromethylated products. Mechanism experiments and theoretical studies revealed that the kinetic effect of the irreversible HAT process resulted in the reversal of the regioselectivity of this scenario, leading to the formation of a less stable α‐difluoroalkyl radical regioisomer. On basis of this new reaction of gem‐difluoroalkene, the iron‐promoted hydrohalogenation of gem‐difluoroalkenes for the efficient synthesis of aliphatic chlorodifluoromethyl‐, bromodifluoromethyl‐ and iododifluoromethyl‐containing compounds was developed. Particularly, this novel hydrohalogenation of gem‐difluoroalkenes provided an effect and large‐scale access to various iododifluoromethylated compounds of high value for synthetic application.

Enhanced performance of thermally activated delayed fluorescent light emitting diodes by optimized host polarity

The interaction between the intrinsic polarity of the host material and the TADF guest material affects charge injection and transport, exciton formation, charge recombination, and emission mechanisms. Therefore, understanding and controlling the interaction between the intrinsic polarity of the host material and the TADF guest material is very important to realize efficient TADF-OLED devices. This study investigated the molecular interaction between different polar host materials and a thermally activated delayed fluorescence material (DMAc-PPM). It has been found that interaction between the host and guest (π-π stacking interaction, multiple CH/π contacts) greatly influence the molecular transition dipole moment orientation of the guest. And the OLED devices based on the strong polar host (DPEPO) exhibited the highest EQEmax and lowest luminescence intensity, while devices using the weaker polar hosts mCP and CBP achieved higher luminance and lower EQEmax. Then, the strong polar host DPEPO was mixed with the weaker polar hosts CBP and mCP, respectively. The devices prepared based on the mixed-host DPEPO: mCP showed a 2.2 times improvement in EQEmax from 6.3% to 20.1% compared to the single-host mCP. The devices prepared based on the mixed-host DPEPO: CBP showed a 3.1 times improvement in luminance intensity from 1023 cd/m2 to 4236 cd/m2 compared to the single host of DPEPO. This suggests that optimizing the polarity of host materials has the potential to enhance the performance of solution prepared OLED devices.

A DFT study of the adsorption of fouling molecules (metal sulfides and hydroxides) onto TiZrO4 ceramic membranes

Ceramic membrane fouling is a constraint in the treatment of acid mine drainage (AMD), leading to a decrease in efficiency over time. Here, it is described via first-principles calculations the physical and chemical phenomena occurring on the surface of TiZrO4 filtration membranes due to the adsorption of eight potential fouling compounds [CuS, FeS, Fe2S3, CaS, Al(OH)3, Fe(OH)3, Fe(OH)2, and Cu(OH)2]. The interaction of these fouling molecules was performed onto nanostructured TiZrO4 surfaces with several pores representing the filtration membranes employed in the treatment of AMD. The adsorption energies reveal that the adsorption is feasible with all the fouling molecules studied, and it is strongly related to the molecular polarity of the adsorbate. Consequently, the adsorption of metal sulfides is more feasible than hydroxides with adsorption orders of CaS>FeS>CuS>Fe2S3, and Al(OH)3>Fe-hydroxides>Cu(OH)2. The outcomes suggest that the metal sulfide adsorption depends on the adsorbate intrinsic polarity, solvent effects, adsorbate van der Waals radius, and membrane surface topology, while the adsorption of hydroxides is less influenced by the last two factors. Density-based binding and energy decomposition analyses indicate strong electrostatic attractions and covalent bonds at the adsorbate-membrane interface supporting the chemical fouling onto ceramic filtration membranes. According to our theoretical results and the elevated concentration of Cu and Fe in AMD, we propose that FeS and CuS are mainly responsible for the fouling onto TiZrO4 membrane surfaces. These results offer valuable information on the adsorption phenomena at TiZrO4 membrane surfaces, which can be useful for metallurgy, industrial water treatment, food industry, biotechnology, and pharmaceutical applications.

Investigation of imaging the somatostatin receptor by opening the blood-brain barrier with melittin – A feasibility study using positron emission tomography and [64Cu]Cu-DOTATATE

DOTATATE is a somatostatin peptide analog used in the clinic to detect somatostatin receptors which are highly expressed on neuroendocrine tumors. Somatostatin receptors are found naturally in the intestines, pancreas, lungs, and brain (mainly cortex). In vivo measurement of the somatostatin receptors in the cortex has been challenging because available tracers cannot cross the blood-brain barrier (BBB) due to their intrinsic polarity. A peptide called melittin, a main component of honeybee venom, has been shown to disrupt plasma membranes and increase the permeability of biological membranes. In this study, we assessed the feasibility of using melittin to facilitate the passage of [64Cu]Cu-DOTATATE through the BBB and its binding to somatostatin receptors in the cortex. Evaluation included in vitro autoradiography on Long Evans rat brains to estimate the binding affinity of [64Cu]Cu-DOTATATE to the somatostatin receptors in the cortex and an in vivo evaluation of [64Cu]Cu-DOTATATE binding in NMRI mice after injection of melittin. This study found an in vitro Bmax = 89 ± 4 nM and KD = 4.5 ± 0.6 nM in the cortex, resulting in a theoretical binding potential (BP) calculated as Bmax/KD ≈ 20, which is believed suitable for in vivo brain PET imaging. However, the in vivo results showed no significant difference between the control and melittin injected mice, indicating that the honeybee venom failed to open the BBB. Additional experiments, potentially involving faster injection rates are required to verify that melittin can increase brain uptake of non-BBB permeable PET tracers. Furthermore, an evaluation of whether a venom with a narrow therapeutic range can be used for clinical purposes needs to be considered.

Sulfide-based MOF material modification of separators: enhancing performance of lithium-sulfur batteries by suppressing shuttle effect

ABSTRACT Lithium-sulfur batteries (LSBs) are extensively studied owing to their high theoretical capacity and low cost. However, the shuttle effect of lithium-sulfur batteries hinders their development. In this study, we obtained a modified separator to inhibit the shuttle effect through physical and chemical adsorption. The CoS2 nanosheets (CSNS) derived from a cobalt-based metal-organic framework (Co-MOF) were synthesized by a simple two-step method involving hydrothermal sulfurization and thermal decomposition. The material was then coated onto a Polypropylene (PP) separator using vacuum filtration and assembled into a LSB for systematic testing and research of its electrochemical performance and mechanism. Thanks to the intrinsic polarity of the CSNs and more active sites brought by the Co-MOF material, the modified separator has strong chemical adsorption and catalytic effects on polysulfides, anchoring and accelerating their conversion. When using the CSNs-PP separator, the LSB achieved a high initial capacity of 1002.4 mAh g−1 at 1 C, with only a 0.099% decay per cycle after 500 cycles. The modified separator effectively alleviating the shuttle effect, reducing internal resistance, weakening reaction polarization, and improving the specific capacity, stability, and reversibility of the battery.

Unravelling Size-Dependent and Coupled Properties in Mechanical Metamaterials: A Couple-Stress Theory Perspective.

The lack of material characteristic length scale prevents classical continuum theory (CCT) from recognizing size effect. Additionally, the even-order material property tensors associated with CCT only characterize the materials' centrosymmetric behavior and overlook their intrinsic chirality and polarity. Moreover, CCT is not reducible to 2D and 1D space without adding couples and higher-order deformation gradients. Despite several generalized continuum theories proposed over the past century to overcome the limitations of CCT, the broad application of these theories in the field of mechanical metamaterials has encountered significant challenges. These obstacles primarily arise from a limited understanding of the material coefficients associated with these theories, impeding their widespread adoption. Implementing a bottom-up approach based on augmented asymptotic homogenization, a consistent and self-sufficient effective couple-stress theory for materials with microstructures in 3D, 2D, and 1D spaces is presented. Utilizing the developed models, material properties associated with axial-twist, shear-bending, bending-twist, and double curvature bending couplings in mechanical metamaterials are characterized. The accuracy of these homogenized models is investigated by comparing them with the detailed finite element models and experiments performed on 3D-printed samples. The proposed models provide a benchmark for the rational design, classification, and manufacturing of mechanical metamaterials with programmable coupleddeformation modes.

Bi3O2.5Se2: a two-dimensional high-mobility polar semiconductor with large interlayer and interfacial charge transfer.

Two-dimensional semiconductors with large intrinsic polarity are highly attractive for applications in high-speed electronics, ultrafast and highly sensitive photodetectors and photocatalysis. However, previous studies mainly focus on neutral layered polar 2D materials with limited vertical dipoles and electrostatic potential difference (typically <1.5 eV). Here, using the first-principles calculations, we systematically investigated the polarity of few-layer Bi3O2.5Se2 semiconductors with ultrahigh predicted room-temperature carrier mobility (1790 cm2 V-1 s-1 for the monolayer). Thanks to its unique non-neutral layered structure, few-layer Bi3O2.5Se2 contributes to a substantial interlayer charge transfer (>0.5 e-) and almost the highest electrostatic potential difference (ΔΦ) of ∼4 eV among the experimentally attainable 2D layered materials. More importantly, positioning graphene on different charged layers ([Bi2O2.5]+ or [BiSe2]-) switches the charge transfer direction, inducing selective n-doping or p-doping. Furthermore, we can use polar Bi3O2.5Se2 as an exemplary assisted gate to gain additional holes or electrons except for the external electric field, thus breaking the traditional limitations of gate tunability (∼1014 cm-2) observed in experimental settings. Our work not only expands the family of polar 2D semiconductors, but also makes a conceptual advance on using them as an assisted gate in transistors.

CoFe2O4 nanoparticles modified amidation of N-doped carbon nanofibers hybrid catalysts to accelerate electrochemical kinetics of Li-S batteries with high sulfur loading

Lithium-sulfur battery have been considered as promising energy storage devices because of its superiority in energy density. However, the low active material utilization, low sulfur loading, shuttle effect and torpid kinetics of polysulfides, and poor cycling stability limit its commercial applications. Herein, the functionalized nitrogen doped carbon nanofibers containing amide groups were designed by electrospun and polyamidoamine dendrimer (PAMAM) solution impregnation techniques. The obtained amide groups modified nitrogen-doped carbon nanofibers (ANF) were combined with spinel CoFe2O4 (CFO) nanoparticles (CFOANF) via hydrothermal method to design as membrane electrode containing Li2S6 catholyte for lithium-sulfur batteries. The introduction of nitrogen doped and amide groups modified ANF can increase fibers polarity, which have chemical adsorption capability toward lithium polysulfides. CFO nanoparticles can further absorb the soluble polysulfides by strong chemical interaction due to its intrinsic polarity and also serve as a catalyst to promote the redox kinetics of polysulfides conversion. Benefiting from the synergism of the physical confinement, polar chemical adsorption, and catalytic conversion, the as-prepared CFOANF delivers excellent electrochemical performances at high sulfur loading. The as-prepared CFOANF membrane with 6.3 mg cm−2 sulfur loading delivers a high initial capacity of 940 mAh g−1 and excellent long-term cycling stability up to 450 cycles with a low decay rate 0.059 % per cycle at 0.2C. Remarkably, even at 12.6 mg cm−2 and 16.4 mg cm−2 sulfur loading, the CFOANF membrane electrodes show high capacity of 9.7 mAh cm−2 and 11.8 mAh cm−2, respectively. The results show that the chemically anchoring polysulfides and catalyzing redox reaction by multifunctional CFOANF hybrid composite is promising for assembling with a high sulfur loading electrode, which exhibits a superior electrochemical performance in lithium-sulfur batteries.

Enhanced polysulfides conversion with hybrid bipolar membrane composed of CoSe2 and amide-functionalized CNTs composites for lithium sulfur batteries

Lithium sulfur battery has been considered as promising energy storage devices because of its superiority in energy density. However, the sulfur loading, low active material utilization, shuttle effect and torpid kinetic of polysulfides, and poor cycling stability limit its commercial applications. Herein, a hybrid bipolar membrane composed cobalt diselenide nanoparticles and amide-functionalized CNTs (CoSe2@A-CNTs) composites has been fabricated by the combination of hydrothermal and vacuum filtration technology, and contained Li2S6 catholyte for lithium sulfur batteries. The introduction of amidation functional groups enhance the polarity of the mesoporous CNTs surface and promote adsorption capability toward lithium polysulfides. The intrinsic polarity of CoSe2 nanoparticles can further adsorb the soluble polysulfides and serve as catalysts to promote the redox kinetics of polysulfides conversion. Benefiting from the synergism of physical confinement, polar chemical adsorption, and catalytic conversion, the as-prepared CoSe2@A-CNTs delivers excellent electrochemical performances at high sulfur loading. The lithium sulfur cell with CoSe2@A-CNTs membrane with 4.8 mg cm−2 sulfur loading exhibits a high initial capacity of 1009.7 mAh g−1 and excellent long-term cycling stability up to 300 cycles with a low decay rat 0.07 % per cycle at 0.2C. Remarkably, even at 9.6 mg cm−2 sulfur loading, the CoSe2@A-CNTs membrane displays high area capacity of 7.5 mAh cm−2 and maintains 6 mAh cm−2 over 100 cycles. The results show that the efficient chemical anchoring polysulfides and catalyzing redox reaction by multifunctional CoSe2@A-CNTs hybrid composites is promising for assembling with a high sulfur loading electrode, which exhibits a superior electrochemical performance in lithium sulfur batteries.

Comparative Analysis of Protein Surface Hydrophobicity Maps Determined by Sparse Sampling INDUS and Spatial Aggregation Propensity.

Protein surface hydrophobicity plays a central role in various biological processes such as protein folding and aggregation, as well as in the design and manufacturing of biotherapeutics. While the hydrophobicity of protein surface patches has been linked to their constituent residue hydropathies, recent research has shown that protein surface hydrophobicity is more complex and characterized by the response of water to these surfaces. In this work, we employ water density perturbations to map the surface hydrophobicity of a set of model proteins using sparse indirect umbrella sampling simulations (SSI). This technique is used to identify hydrophobic surface patches for the set of model proteins, and the results are compared to those obtained from the widely adopted spatial aggregation propensity (SAP) technique. While SAP-based calculations show agreement with SSI in some cases, there are several examples of disagreement. We identify four general classes of difference in behavior and study factors that contribute to these differences. We find that the SAP method can sometimes mask the effect of weakly nonpolar or isolated nonpolar residues that can lead to strong hydrophobic patches on the protein surface. In addition, hydrophobic patches identified by SAP can exhibit shifts in both position and strength on the SSI map. Our results demonstrate that the combination of topography and chemical context controls the hydrophobicity of a given patch above and beyond the intrinsic polarity of the residues present on the patch surface. The availability of more accurate protein hydrophobicity maps in concert with new classes of hydrophobic molecular descriptors may create significant opportunities for in silico prediction of protein behavior for a range of applications, such as protein design, biomanufacturability, and downstream bioprocessing.