Naturally Occurring Terpenes:A Promising Class of Organic Molecules to Address Influenza Pandemics

Since the olden times,infectious diseases have largely affected human existence.The newly emerged infections are excessively caused by viruses that are largely associated with mammal reservoirs.The casualties of these emergencies are significantly influenced by the way human beings interact with the reservoirs,especially the animal ones.In our review we will consider the evolutionary and the ecological scales of such infections and their consequences on the public health,with a focus on the pathogenic influenza A virus.The nutraceutical properties of fungal and plant terpene-like molecules will be linked to their ability to lessen the symptoms of viral infections and shed light on their potential use in the development of new drugs.New challenging methods in antiviral discovery will also be discussed in this review.The authors believe that pharmacognosy is the“wave of future pharmaceuticals”,as it can be continually produced and scaled up under ecofriendly requirements.Further diagnostic methods and strategies however are required to standardise those naturally occurring resources.

Thin-film growth behavior of non-planar vanadium oxide phthalocyanine

The thin film properties of organic semiconductors are very important to the device performance.Herein,non-planar vanadyl phthalocyanine(VOPc)thin films grown on rigid substrates of indium tin oxide,silicon dioxide,and flexible substrate of kapton by organic molecular beam deposition under vacuum conditions are systematically studied via atomic force microscopy and x-ray diffraction.The results clearly reveal that the morphology and grain size are strongly dependent on the substrate temperature during the process of film deposition.Meanwhile,the VOPc films with the structure of phase I or phase II can be modulated via in situ annealing and post-annealing temperature.Furthermore,the crystalline structure and molecular orientation of vapor-deposited VOPc can be controlled using molecular template layer 3,4,9,10-perylenetetracarboxylic dianhydride(PTCDA),the VOPc film of which exhibits the phase I structure.The deep understanding of growth mechanism of non-planar VOPc film provides valuable information for controlling structure-property relationship and accelerates the application in electronic and optoelectronic devices.

Recent progress in polymerization-induced self-assembly:From the perspective of driving forces

Polymerization-induced self-assembly(PISA)enables the simultaneous growth and self-assembly of block copolymers in one pot and therefore has developed into a high-efficiency platform for the preparation of polymer assemblies with high concentration and excellent reproducibility.During the past decade,the driving force of PISA has extended from hydrophobic interactions to other supramolecular interactions,which has greatly innovated the design of PISA,enlarged the monomer/solvent toolkit,and endowed the polymer assemblies with intrinsic dynamicity and responsiveness.To unravel the important role of driving forces in the formation of polymeric assemblies,this review summarized the recent development of PISA from the perspective of driving forces.Motivated by this goal,here we give a brief overview of the basic principles of PISA and systematically discuss the various driving forces in the PISA system,including hydrophobic interactions,hydrogen bonding,electrostatic interactions,andπ-πinteractions.Furthermore,PISA systems that are driven and regulated by crystallization or liquid crystalline ordering were also highlighted.

Exploring the configuration space of elemental carbon with empirical and machine learned interatomic potentials

We demonstrate how the many-body potential energy landscape of carbon can be explored with the nested sampling algorithm,allowing for the calculation of its pressure-temperature phase diagram.We compare four interatomic potential models:Tersoff,EDIP,GAP-20 and its recently updated version,GAP-20U.Our evaluation is focused on their macroscopic properties,melting transitions,and identifying thermodynamically stable solid structures up to at least 100 GPa.The phase diagrams of the GAP models show good agreement with experimental results.However,we find that the models’description of graphite includes thermodynamically stable phases with incorrect layer spacing.By adding a suitable selection of structures to the database and re-training the potential,we have derived an improved model—GAP-20U+gr—that suppresses erroneous local minima in the graphitic energy landscape.At extreme high pressure nested sampling identifies two novel stable structures in the GAP-20 model,however,the stability of these is not confirmed by electronic structure calculations,highlighting routes to further extend the applicability of the GAP models.

P450-mediated dehydrotyrosine formation during WS9326 biosynthesis proceeds via dehydrogenation of a specific acylated dipeptide substrate

WS9326A is a peptide antibiotic containing a highly unusual N-methyl-E-2-3-dehydrotyrosine(NMet-Dht)residue that is incorporated during peptide assembly on a non-ribosomal peptide synthetase(NRPS).The cytochrome P450 encoded by sas16(P450Sas)has been shown to be essential for the formation of the alkene moiety in NMet-Dht,but the timing and mechanism of the P450Sas-mediatedα,β-dehydrogenation of Dht remained unclear.Here,we show that the substrate of P450Sas is the NRPS-associated peptidyl carrier protein(PCP)-bound dipeptide intermediate(Z)-2-pent-1′-enyl-cinnamoyl-Thr-N-Me-Tyr.We demonstrate that P450Sas-mediated incorporation of the double bond follows N-methylation of the Tyr by the N-methyl transferase domain found within the NRPS,and further that P450Sas appears to be specific for substrates containing the(Z)-2-pent-1’-enyl-cinnamoyl group.A crystal structure of P450Sas reveals differences between P450Sas and other P450s involved in the modification of NRPS-associated substrates,including the substitution of the canonical active site alcohol residue with a phenylalanine(F250),which in turn is critical to P450Sas activity and WS9326A biosynthesis.Together,our results suggest that P450Sas catalyses the direct dehydrogenation of the NRPS-bound dipeptide substrate,thus expanding the repertoire of P450 enzymes that can be used to produce biologically active peptides.

1,10-邻菲啉衍生物钌配合物的合成、表征及与DNA和BSA的相互作用

通过2-(4-吡啶)-咪唑[4,5-f]-1,10-邻菲啉(L_1)与[Ru(η~6-cymene)(μ-Cl) Cl]_2反应合成了3种新型芳基钌配合物,并利用新配体2-(4-咪唑基苯基)咪唑[4,5-f]-1,10-邻菲啉(L_2)与RuCl_3反应合成了配合物4.利用核磁共振波谱、质谱等对配合物进行了表征.通过紫外光谱和圆二色谱研究了配合物在缓冲溶液中的稳定性及与CT-DNA的相互作用,利用荧光光谱研究了配合物与牛血清蛋白的作用,用乌氏黏度计测试了配合物对DNA黏度的影响,并通过荧光光谱、凝胶电泳研究了配合物4在不同pH条件下的荧光响应及与pBR322 DNA的作用.结果表明,配合物通过嵌入的方式与DNA作用,并对DNA的二级结构产生影响;配合物1～4均可与牛血清蛋白的一个位点发生相互作用并使其发生静态荧光猝灭.配合物4在光照条件下有活性氧生成,可以使pBR322 DNA断裂并在酸性溶液中荧光增强.

联吡啶衍生物芳基钌配合物的合成及其与DNA、蛋白质相互作用

以2种配体4,4′-dimethyl-2,2′-bipyridine(L1)和4′-methyl-(2,2′-bipyridine)-4-carbaldehyde oxime(L2),分别与芳基钌二聚体[RuCl_2(η~6-p-cymene)]2合成了2种新型单核配合物[Ru(η~6-p-cymene)(L1)Cl]Cl(1)和[Ru(η6-p-cymene)(L2)Cl]Cl(2)。应用元素分析、ESI-MS和~1H NMR对配合物的组成和结构进行表征,通过紫外光谱法和荧光光谱法研究了配合物的水解及其与CT-DNA和血清蛋白的结合性质,并且进行了细胞毒性研究。结果表明,在水溶液中配合物1比2在动力学上更稳定(k:0.383 h^(-1)(1)、1.458 h^(-1)(2));配合物均通过嵌入作用与双链DNA结合,但2有较强的结合能力(Kb:7.8×10~3L·mol^(-1)(1)、1.86×10~4L·mol^(-1)(2))。配合物均能与蛋白质发生相互作用,引起蛋白静态猝灭,但1作用较强(KA:1.04×10~5L·mol^(-1)(1)、8.62×10~4L·mol^(-1)(2))。配合物与蛋白的较强结合能力,可能是其细胞毒性不高的原因。

单核锇配合物的合成、晶体结构及其与DNA的作用

使用溶剂热合成法,以p-bitmb配体(1,4-二(1-咪唑基-亚甲基)-2,3,5,6-四甲基苯)与[(η6-cymene)Os(μ-Cl)Cl]2或[(η6-bip)Os(μ-Cl)Cl]2为原料,合成了2种单核芳基锇配合物,并利用核磁、质谱、元素分析和X射线单晶衍射等手段对配合物进行了表征。配合物1属于单斜晶系,P21/c空间群,为一个单核锇的结构。中心锇原子与2个配体p-bitmb上的氮原子以及氯原子进行配位,2个配体的另一个咪唑基团通过一个亚甲基碳原子进行连接形成咪唑嗡离子,形成一个类似"碗"状的结构。一个氯离子通过氢键装载在结构的空腔内。利用核磁共振氢谱研究了结构中亚甲基的来源,并研究了配合物在缓冲溶液中的稳定性。用紫外吸收光谱、圆二色谱以及粘度法研究了配合物与DNA的相互作用,结果表明,配合物中的亚甲基来自于溶剂二氯甲烷。配合物以嵌入的方式与CT-DNA相互作用,结合常数分别为3.222×10~4 L·mol-1 (1)和1.53×10~4 L·mol-1 (2),同时配合物会减弱DNA的碱基堆积作用并可以使DNA发生解旋。

The origin of uniaxial negative thermal expansion in layered perovskites

Why is it that ABO3 perovskites generally do not exhibit negative thermal expansion(NTE)over a wide temperature range,whereas layered perovskites of the same chemical family often do?It is generally accepted that there are two key ingredients that determine the extent of NTE:the presence of soft phonon modes that drive contraction(have negative Grüneisen parameters);and anisotropic elastic compliance that predisposes the material to the deformations required for NTE along a specific axis.This difference in thermal expansion properties is surprising since both ABO3 and layered perovskites often possess these ingredients in equal measure in their high-symmetry phases.Using first principles calculations and symmetry analysis,we show that in layered perovskites there is a significant enhancement of elastic anisotropy due to symmetry breaking that results from the combined effect of layering and condensed rotations of oxygen octahedra.This feature,unique to layered perovskites of certain symmetry,is what allows uniaxial NTE to persist over a large temperature range.This fundamental insight means that symmetry and the elastic tensor can be used as descriptors in high-throughput screening and to direct materials design.

Organosilicon leather coating technology based on carbon peak strategy

Based on the demand of carbon peak and carbon emission reduction strategy,divinyl-terminated polydimethyl-siloxane(^(Vi)PDMS^(Vi)),poly(methylhydrosiloxane)(PMHS),divinyl-terminated polymethylvinylsiloxane(ViPMVSVi),and fumed silica were used as primary raw materials,polydimethylsiloxane(PDMS)synthetic leather coating was in situ constructed by thermally induced hydrosilylation polymerization on the synthetic leather substrate.The effect of the viscosity of^(Vi)PDMS^(Vi),the active hydrogen content of PMHS,the molar ratio of vinyl groups to active hydrogen,the dosage of ViPMVSVi and fumed silica on the performance of PDMS polymer coating,including mechanical properties,cold resistance,flexural resistance,abrasion resistance,hydrophobic and anti-fouling properties were investigated.The results show that^(Vi)PDMS^(Vi)with high vinyl content and PMHS with low active hydrogen content is more conducive to obtaining organosilicon coating with better mechanical properties,the optimized dosage of ViPMVSVi and fumed silica was 7 wt%and 40 wt%,respectively.In this case,the tensile strength and the broken elongation of the PDMS polymer coating reached 5.96 MPa and 481%,showing reasonable mechanical properties for leather coating.Compared with polyurethane based or polyvinyl chloride based synthetic leather,the silicon based synthetic leather prepared by this method exhibits excellent cold resistance,abrasion resistance,super hydrophobicity,and anti-fouling characteristics.

Not yet defect-free: the current landscape for women in computational materials research

INTRODUCTION“I really am not seeing how women are still considered disadvantaged in our field.”This phrase is heard all-too-often by woman scientists across many fields.And while attitudes on gender equity and parity have considerably improved in recent history,there are still measurable inequities stemming from systemic bias in the career progression,recognition,and perception of women in the sciences,including our sub-field of computational materials research.Addressing the obstacles to equity is in the interests of all of us.Making research inclusive is critical,not only from an ethical standpoint,but also for attracting and retaining dedicated and talented minds,enhancing the vibrancy of all fields,and nurturing a diverse range of ideas.

Machine-learned interatomic potentials for alloys and alloy phase diagrams

We introduce machine-learned potentials for Ag-Pd to describe the energy of alloy configurations over a wide range of compositions.We compare two different approaches.Moment tensor potentials(MTPs)are polynomial-like functions of interatomic distances and angles.The Gaussian approximation potential(GAP)framework uses kernel regression,and we use the smooth overlap of atomic position(SOAP)representation of atomic neighborhoods that consist of a complete set of rotational and permutational invariants provided by the power spectrum of the spherical Fourier transform of the neighbor density.Both types of potentials give excellent accuracy for a wide range of compositions,competitive with the accuracy of cluster expansion,a benchmark for this system.While both models are able to describe small deformations away from the lattice positions,SOAP-GAP excels at transferability as shown by sensible transformation paths between configurations,and MTP allows,due to its lower computational cost,the calculation of compositional phase diagrams.Given the fact that both methods perform nearly as well as cluster expansion but yield off-lattice models,we expect them to open new avenues in computational materials modeling for alloys.

Aurone derivatives as Vps34 inhibitors that modulate autophagy

We report in this study the identification of a natural product-like antagonist(1a) of Vps34 as a potent autophagy modulator via structure-based virtual screening. Aurone derivative 1a strongly inhibited Vps34 activity in cell-free and cell-based assays. Significantly, 1a prevents autophagy in human cells induced either by starvation or by an mT OR inhibitor. In silico modeling and kinetic data revealed that 1a could function as an ATP-competitive inhibitor of Vps34. Moreover, it suppressed autophagy in vivo and without inducing heart or liver damage in mice. 1a could be utilized as a new motif for more selective and efficacious antagonists of Vps34 for the potential treatment of autophagy-related human diseases.

Weak mismatch epitaxy and structural feedback in graphene growth on copper foil

Graphene growth by low-pressure chemical vapor deposition on low cost copper foils shows great promise for large scale applications. It is known that the local crystallography of the foil influences the graphene growth rate. Here we find an epitaxial relationship between graphene and copper foil. Interfacial restructuring between graphene and copper drives the formation of （nl0） facets on what is otherwise a mostly Cu（100） surface, and the facets in turn influence the graphene orientations from the onset of growth. Angle resolved photoemission shows that the electronic structure of the graphene is decoupled from the copper indicating a weak interaction between them. Despite this, two preferred orientations of graphene are found, ±8° from the Cu[010] direction, creating a non-uniform distribution of graphene grain boundary misorientation angles. Comparison with the model system of graphene growth on single crystal Cu（110） indicates that this orientational alignment is due to mismatch epitaxy. Despite the differences in symmetry the orientation of the graphene is defined by that of the copper. We expect these observations to not only have importance for controlling and understanding the growth process for graphene on copper, but also to have wider implications for the growth of two-dimensional materials on low cost metal substrates.

Organosilicon leather coating technology based on carbon peak strategy

Based on the demand of carbon peak and carbon emission reduction strategy, divinyl-terminated polydimethyl-siloxane (ViPDMSVi), poly(methylhydrosiloxane) (PMHS), divinyl-terminated polymethylvinylsiloxane (ViPMVSVi), and fumed silica were used as primary raw materials, polydimethylsiloxane (PDMS) synthetic leather coating was in situ constructed by thermally induced hydrosilylation polymerization on the synthetic leather substrate. The effect of the viscosity of ViPDMSVi, the active hydrogen content of PMHS, the molar ratio of vinyl groups to active hydrogen, the dosage of ViPMVSVi and fumed silica on the performance of PDMS polymer coating, including mechanical properties, cold resistance, flexural resistance, abrasion resistance, hydrophobic and anti-fouling properties were investigated. The results show that ViPDMSVi with high vinyl content and PMHS with low active hydrogen content is more conducive to obtaining organosilicon coating with better mechanical properties, the optimized dosage of ViPMVSVi and fumed silica was 7 wt% and 40 wt%, respectively. In this case, the tensile strength and the broken elongation of the PDMS polymer coating reached 5.96 MPa and 481%, showing reasonable mechanical properties for leather coating. Compared with polyurethane based or polyvinyl chloride based synthetic leather, the silicon based synthetic leather prepared by this method exhibits excellent cold resistance, abrasion resistance, super hydrophobicity, and anti-fouling characteristics.

Anion-Responsive Manganese Porphyrin Facilitates Chloride Transport and Induces Immunogenic Cell Death

Chloride is the most abundant anion in living systems.Most natural or synthetic chloride anionophores function via hydrogen-bonding interactions.However,dynamic metal-anion coordination can also be an efficient way of transporting chloride across membranes.Here,we investigate anion transport by manganese(Ⅲ)meso-tetraphenylporphyrin chloride{[Mn(TPP)Cl],TPP=meso-tetraphenylporphyrin}complex that exhibits labile axial coordination.[Mn(TPP)Cl]showed high chloride transport activity in a bilayer vesicle model with an EC_(50) value of 4.42×10^(−3) mol%.In living cells,[Mn(TPP)Cl]induced rapid chloride influx and autophagy.The release of Ca^(2+)and adenosine 5′-triphosphate(ATP),as well as the relocation of calreticulin,revealed that[Mn(TPP)Cl]caused immunogenic cell death.Proteomic analysis indicated that[Mn(TPP)Cl]impaired several physiological processes,including DNA synthesis,transcription,mitochondrial respiration,RNA translation,and immune response.Our study suggests that dynamic metal-anion interactions across membranes might provide a practical strategy for the interference of chloride homeostasis.