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In this paper, a feed-forward back-propagation artificial neural network (ANN) is proposed to correlate and predict the thermal conductivity from the triple point temperature up to 0.98 times critical temperature (

A simple corresponding state-based correlation, whose analytical expression contains just one term with an exponential function, is proposed to calculate the surface tension of 36 silanes, 29 carboxylic acids, and 81 refrigerants as a function of temperature. This correlation only requires critical temperature, maximum value of surface tension, and its corresponding temperature in the DIPPR database as inputs for each liquid considered. The correlation allows us to calculate the accepted DIPPR data for silanes with a mean absolute average deviation (AAD) of 2.75%, 2.42% for acids, and 3.32% for refrigerants. Moreover, it gives AADs below 3% for 99 fluids. The mean deviation for the 146 fluids is 3.0%, which is practically equal to the results obtained when two terms are used in the analytical expression.

A new corresponding-states model for the calculation of the surface tension of silanes is proposed. It requires as input properties the critical point temperature, the minimum temperature at which ...

Metastasis of mesenchymal tumor cells is traditionally considered as a single-cell process. Here, we report an emergent collective phenomenon in which the dissemination rate of mesenchymal breast cancer cells from three-dimensional tumors depends on the tumor geometry. Combining experimental measurements and computational modeling, we demonstrate that the collective dynamics is coordinated by the mechanical feedback between individual cells and their surrounding extracellular matrix (ECM). We find the tissue-like fibrous ECM supports long-range physical interactions between cells, which turn geometric cues into regulated cell dissemination dynamics. Our results suggest that migrating cells in three-dimensional ECM represent a distinct class of an active particle system in which the collective dynamics is governed by the remodeling of the environment rather than direct particle-particle interactions.

Dense packings of hard particles are useful models for condensed matters including crystalline and glassy state of solids, simple liquids, granular materials and composites. It is very challenging to devise predictive theories of random packings, due to the intrinsic non-equilibrium and non-local nature of the system. Here, we develop a formalism for accurately predicting the density (i.e., fraction of space covered by the particles) ηMRJ of the maximally random jammed (MRJ) packing state of a wide spectrum of congruent non-spherical hard particles in three-dimensional Euclidean space [Doublestruck R]3, via analytical continuation of the corresponding fluid equation of state (EOS). This formalism is based on the assumption that the fluid branch of the EOS can be analytically extended into the meta-stable region, which leads to a diverging pressure at the jamming point (i.e., the MRJ state). This allows us to estimate ηMRJ as the pole in the EOS, which can be expressed in terms of the virial coefficients encoding intrinsic local n-body packing information of the particles, and depending alone on particle shape. The accuracy of our formalism is verified using the hard sphere system and is subsequently applied to a wide spectrum of non-spherical shapes. The predictions are compared to numerical results whenever possible, and excellent agreements are found.

The asymptotic expansion method is used to derive analytical expressions for the equations of state of 14 hard polyhedron fluids such as cube, octahedron, rhombic dodecahedron, etc., by knowing the values of only the first eight virial coefficients. The results for the compressibility factor were compared with the most recent ones reported in the literature and obtained by computer simulations. Good results (averaged deviations below 1%) are found for the 8 fluids studied. On the other hand, the method seems to be inadequate, at least with the presently available values for the virial coefficients and compressibility factors, for 4 polyhedron fluids. Unfortunately, sometimes the method does not give low deviations at high densities or it gives excessively high values for the location of the pole. As an advantage, the value of the pole for the compressibility factor is always positive, which is not observed when other methods are used.

In this paper, a new corresponding state principle (CSP)-based model is proposed to calculate the surface tension of hydrocarbons based on the National Institute of Standards and Technology (NIST) database. This model requires the critical point temperature, the lowest temperature available for surface tension data and the corresponding maximum surface tension value as inputs. It includes two adjustable coefficients which are fitted by using NIST data of three hydrocarbons. To test the applicability of this model, we applied it to predict the surface tension values of other 16 hydrocarbons. For all the 19 hydrocarbons available in NIST database, the average absolute deviations of 16 hydrocarbons are less than 5%. We also compared this new proposed model with other three existing corresponding state models, and found that this model is the best in predicting the surface tension data of hydrocarbons.

We collected data of the surface tension versus the temperature of 28 saturated refrigerant fluids available in the NIST database. These data are used to build a new corresponding state-based correlation. Compared with other previously proposed correlations, the current one has the advantages of both simplicity and accuracy. To check the ability of correlations, we compared the numerically calculated/predicted results with the data in the NIST database. It is found that the average absolute deviations are less than 10% for 26 refrigerants and less than 1% for 8 refrigerants.

Collective cell migration in 3D extracellular matrix (ECM) is crucial to many physiological and pathological processes. Migrating cells can generate active pulling forces via actin filament contraction, which are transmitted to the ECM fibers and lead to a dynamically evolving force network in the system. Here, we elucidate the role of this force network in regulating collective cell behaviors using a minimal active-particle-on-network (APN) model, in which active particles can pull the fibers and hop between neighboring nodes of the network following local durotaxis. Our model reveals a dynamic transition as the particle number density approaches a critical value, from an "absorbing" state containing isolated stationary small particle clusters, to an "active" state containing a single large cluster undergoing constant dynamic reorganization. This reorganization is dominated by a subset of highly dynamic "radical" particles in the cluster, whose number also exhibits a transition at the same critical density. The transition is underlaid by the percolation of "influence spheres" due to the particle pulling forces. Our results suggest a robust mechanism based on ECM-mediated mechanical coupling for collective cell behaviors in 3D ECM.

By using the recently published simulation data for the compressibility factor (M. N. Bannerman, L. Lue and L. V. Woodcock, J. Chem. Phys., 2010, 132, 084507; S. Pieprzyk, M. N. Bannerman, A. C. Branka, M. Chudak and D. Heyes, Phys. Chem. Chem. Phys., 2019, 21, 6886) and the recently published numerical virial coefficients B5–B12 (R. J. Wheatley, Phys. Rev. Lett., 2013, 110, 200601; C. Zhang and B. M. Pettitt, Mol. Phys., 2014, 112, 1427; A. J. Schultz and D. A. Kofke, Phys. Rev. E: Stat., Nonlinear, Soft Matter Phys., 2014, 90, 023301) of hard sphere fluids, we herein report the updated versions of the equations of the state of hard sphere fluids based on the asymptotic expansion method (J. Tian, H. Jiang, Y. Gui and A. Mulero, Phys. Chem. Chem. Phys., 2009, 11, 11213), the Pade approximants (N. Clisby and B. McCoy, J. Stat. Phys., 2006, 122, 15) and the exponential approximants (N. S. Barlow, A. J. Schultz, S. J. Weinstein and D. A. Kofke, J. Chem. Phys., 2012, 137, 204102) and compare them with other recently published equations. It is found that the so-called mKLM equation describes the relation of the compressibility factor versus the packing fraction with the highest accuracy. The asymptotic expansion method based equation Z(−5, 2) is recommended to well describe both the virial coefficients and the compressibility factor.

Due to some similarity of innate immunity between insects and mammals, the study of the molecular mechanism of innate immunity in insects has become a focus of research. However, the exact molecular and cellular basis of immune system in insect remains poorly understood. Characterization of the transcriptomic response to Cd of spider is an effective approach to understanding the innate immunity mechanisms. In this study, we carried out transcriptome sequencing and gene expression analyses to develop molecular resources for Pardosa pseudoannulata venom glands with and without Cd treatments. A total of 92,778 assembled unigenes and 237 Cd stress-associated differentially expressed genes between the Cd-treated and control groups were obtained. Expression profile analysis demonstrated that immunity-related genes involved in bacterial invasion of epithelial cells, leukocyte transendothelial migration, platelet activation, apoptosis, phagosome, and Rap1 signaling pathway were upregulated by Cd exposure, except the genes involved in PPAR signaling pathway were downregulated. Our results provide the first comprehensive transcriptome dataset of venom glands in P. pseudoannulata response to Cd, which is valuable for throws light on the immunotoxicity mechanism of Cd, and the innate immunity complexity.

Hope is a higher-order cognitive construct relating to expectations of or beliefs in wish fulfillment, which has been conceptualized as consisting of 2 components: pathways thinking (the perceived means available to individuals that allow them to achieve their goals) and agency thinking (belief in one's ability to succeed in using the identified pathways). We aimed to clarify the measurement structure of the Chinese version of the Adult Dispositional Hope Scale, using a sample of 751 university student participants. We employed confirmatory factor analysis to compare 1-factor, 2-factor, second-order, and bifactor models. The results showed that all models fit the measured data well. However, the bifactor model had the best fit indices, whereas the second-order model was the most consistent with the theoretical measurement model. To verify that hope theory and the corresponding instruments can be confidently applied to cross-cultural samples, it is necessary to further assess their reliability and validity in a Chinese cultural context through a measurement structure analysis.

Cadmium (Cd) is a heavy metal that can cause irreversible toxicity to animals, and is an environmental pollutant in farmlands. Spiders are considered to be an excellent model for investigating the impacts of heavy metals on the environment. To date, the changes at the molecular level in the cerebral ganglia of spiders are poorly understood. Cd exposure leads to strong damage in the nervous system, such as apoptosis and necrosis of nerve cells, therefore we conducted a transcriptomic analysis of Pardosa pseudoannulata cerebral ganglia under Cd stress to profile differential gene expression (DGE). We obtained a total of 123,328 assembled unigenes, and 1441 Cd stress-associated DEGs between the Cd-treated and control groups. Expression profile analysis demonstrated that many genes involved in calcium signaling, cGMP—PKG signaling, tyrosine metabolism, phototransduction–fly, melanogenesis and isoquinoline alkaloid biosynthesis were up-regulated under Cd stress, whereas oxidative phosphorylation-related, nervous disease-associated, non-alcoholic fatty liver disease-associated, and ribosomal-associated genes were down-regulated. Here, we provide a comprehensive set of DEGs influenced by Cd stress, and heavy metal stress, and provide new information for elucidating the neurotoxic mechanisms of Cd stress in spiders.

A new and simple correlation based on the corresponding-states principle is proposed for the relation of the vaporization enthalpy with the temperature for saturated silanes. The primary accepted data for 7 silanes obtained from the most recent version of the DIPPR database are used as reference to define the model. Then predictions are made for other 29 silanes and compared with DIPPR data. The proposed correlation reproduces these data with average absolute deviations (AAD) lower than 1% for 8 silanes, AAD

Spiders are believed to have enormous potential for indicating heavy metal pollution in ecosystems. The diversity of influencing factors caused significant differences in the toxicities of cadmium (Cd) on spiders. There is limited understanding of the underlying mechanism and response to acute Cd exposure at different concentrations and different poisoning times. We exposed adult female P. subpiraticus to 0.2 mM and 2 mM Cd for 6 and 12 h, respectively, to explore acute Cd toxicities by RNA-seq. We measured the bioaccumulation levels in P. subpiraticus and tested the activities of superoxide dismutase (SOD) and glutathione S-transferase (GST). There were 187, 292, 101 and 155 differentially expressed genes (DEGs) after exposure to 0.2 mM and 2 mM Cd for 6 and 12 h, respectively. The results revealed that Cd accumulated in P. subpiraticus, changed the SOD and GST activities, and caused significant adverse effects at the molecular level on metabolism and immune and oxidative stress, with time- and concentration-dependent differences. Transcriptome analysis showed that acute Cd exposure depressed lipid metabolism and induced protein metabolism, especially serine metabolism. Genes encoding lipoproteins were depressed when exposed to 0.2 mM Cd, while fatty acid-related genes were downregulated under 2 mM Cd stress. In total, 46 cuticle-related genes were upregulated, and 6 cytoskeleton-related genes changed notably in the immune process. Peroxidase-related genes were further upregulated significantly. Meanwhile, the pathways related to metabolism, immunity and oxidative stress were significantly enriched. This report illustrated that acute Cd exposure exerts toxicities on P. subpiraticus and the spiders against acute Cd toxicities by selective differential expression of the genes associated with the physiological process of metabolism and immune and antioxidant stress. This study provides a comprehensive transcriptional basis for understanding the response of the P. sublimations to heavy metals at different concentrations and different treatment times.

In this paper, we proposed a new correlation for the temperature dependent viscosity of saturated refrigerants liquids based on the recent progresses on the relation between surface tension and viscosity of liquids [J. X. Tian et al., Industrial & Engineering Chemistry Research, 53, 9499, 2014] and the temperature dependent surface tension of liquids [S. G. Yang et al., Industrial & Engineering Chemistry Research, 59, 6336, 2020]. By comparing with the experimental data of 80 saturated refrigerants liquids in the DIPPR database, it is found that the proposed correlation can predict the DIPPPR data with average absolute relative deviation (AARD) less than 5% for all the 80 liquids, AARD less than 3% for 76 liquids. These results indicate superior accuracy of the proposed correlation compared to other well-known correlations including the Arrhenius equation and the Vogel-Fulcher-Tamman equation.

A new corresponding-states correlation model for the calculation of the surface tension of refrigerants is proposed. The main difference with respect to other models available in the literature is that this includes the temperature and surface tension values at the triple point as input properties to define the reduced (non-dimensional) properties, and therefore it is applicable to the entire vapour-liquid temperature range in which this property is defined. The model uses the critical point and the triple point temperature of refrigerant R142b as fixed input parameters and four numerical coefficients obtained by a fitting procedure. The adjustable coefficients were calculated by taking into account the data for 33 selected refrigerants for which the surface tension values at the triple point are known. For each fluid the input variables are the critical point temperature, the triple point temperature, and surface tension at the triple point temperature. To check the model's capacity, we used it to calculate the surface tension values of another 50 refrigerants for which the value of this property is not known at the triple point. To do this, we used as input the lowest temperature at which a value of the surface tension is available. In both cases, correlation and prediction, the calculations were done by considering the most up-to-date database presently available for the surface tension of refrigerants. Averaged absolute deviations below 5% were found for 63 of the 83 fluids considered, and only for 4 of them were they greater than 10%. Results for another four corresponding-states models available in the literature were also obtained. That proposed here gave clearly better overall results.

A new general corresponding-states correlation model for the calculation of the surface tension of refrigerants is proposed. The main difference with respect to other models available in the literature is that, in addition to the critical point temperature, the proposed model includes the temperature and surface tension values at the boiling point as input properties to define the reduced (non-dimensional) properties. Only three general adjustable coefficients are needed, which were obtained by a fitting procedure to the data presently available for 80 refrigerants. Averaged absolute deviations below 9.5% are found in all cases, being below 5% for 67 out of the 80 fluids considered. Results for another four corresponding-states models available in the literature are also obtained. The correlation model proposed here gives clearly better overall results, and it is the only one including exclusively temperature and surface tension values as inputs.

Since the birth of transgenic crops expressing Bacillus thuringiensis (Bt) toxin for pest control, the public debate regarding ecological and environmental risks as well as benefits of Bt crops has continued unabated. The impact of Bt crops, especially on non-target invertebrates, has received particular attention. In this review, we summarize and analyze evidences for non-target effects of Bt rice on spiders, major predators in rice fields. Bt rice has been genetically modified to express the Bt protein, which has been shown to be transferred and accumulate in spiders as part of their food chain. Moreover, the Bt protein exhibits unintended effects on the physiology of spiders and spreads to higher trophic levels. Spiders possess unique physiological and ecological characteristics, revealing traits of surrogate species, and are thus considered to be excellent non-target arthropod model systems for study of Bt protein impacts. Due to the complexities of Bt protein transfer and accumulation mechanisms, as well as the apparent lack of information about resulting physiological, biochemical, and ecological effects on spiders, we raise questions and provide recommendations for promising further research.

By using the recently published simulation data for the compressibility factor (M. N. Bannerman, L. Lue and L. V. Woodcock, J. Chem. Phys., 2010, 132, 084507; S. Pieprzyk, M. N. Bannerman, A. C. Branka, M. Chudak and D. Heyes, Phys. Chem. Chem. Phys., 2019, 21, 6886) and the recently published numerical virial coefficients B

The Weibull model is a well-known probability distribution function that uses only two adjustable coefficients, which have a certain mathematical meaning, and can represent a lot of different analytical behaviors. In this paper, we show that the Weibull model can be used to correlate the surface tension values of liquids. For that, we compare this model with the results given by the REFPROP computer program for 117 liquids. While the REFPROP program uses two to six adjustable coefficients depending on the fluid in question, what we propose here is the use of only one or two adjustable coefficients. We show that for 112 out of the 117 fluids the new correlation using two adjustable coefficients deviates by

Long-duration gamma-ray bursts (LGRBs) are generally considered to originate from the massive collapsars. It is believed that the central engine of gamma-ray bursts (GRBs) is a neutrino-dominated accretion flow (NDAF) around a rotating stellar-mass black hole (BH). The neutrino annihilation above the NDAF is a feasible mechanism to power GRB. In this work, we analyse the distributions of the isotropic gamma-ray radiated energy and jet kinetic energy of 48 LGRBs. According to the NDAF and fireball models, we estimate the mean accreted masses of LGRBs in our sample to investigate whether the NDAFs can power LGRBs with the reasonable BH parameters and conversion efficiency of neutrino annihilation. The results indicate that most of the values of the accreted masses are less than $5~M_\odot$ for the extreme Kerr BHs and high conversion efficiency. It suggests that the NDAFs may be suitable for most of LGRBs except for some extremely high energy sources., Comment: 6 pages, 1 figure, accepted for publication in MNRAS

We here report a three-parameter correlation for the temperature T dependent thermal conductivity λ of different kinds of saturated liquids including n-alkanes, refrigerants and others such as argon and nitrogen. The correlation is proven to be more accurate than other known correlations. Compared with the REFPROP data in NIST, the proposed correlation reproduces the corresponding data with the average absolute deviation (AAD) less than 1.20% for all the liquids considered. At the same time, it well holds in a wider temperature range which begins from the triple point temperature and ends at about 0.98 times the critical temperature, at which the thermal conductivity experimentally takes a minimal value for the liquids we study. Engineers and researchers can use the proposed correlation to directly estimate/calculate the thermal conductivity of the liquids considered here with high accuracy. Thermal conductivity related industrial and engineering equipment designs and chemical process designs will benefit from it greatly.

We here report that the corresponding state principle well stands for the temperature dependent thermal conductivity of the saturated refrigerants liquids by using the reduced quantities proposed here. A corresponding state principle based correlation is proposed and proven to be accurate in the temperature range from the triple point temperature to 0.90 times the critical temperature. Additionally, this correlation also stands for the saturated n-alkanes liquids. For the 23 refrigerants and 11 n-alkanes considered here, the proposed correlation can reproduce the REFPROP data with AAD

In this paper, we study the multiple-parameter correlations for the surface tension of saturated liquids. The proposed three-parameter correlation requires only the critical temperature as inputs and is tested by using the NIST REFPROP data for 72 saturated liquids including refrigerants, alkanes and some other simple liquids such as argon, carbon dioxide, etc. It is found that this correlation well stands in the whole temperature range from the triple point to the critical point with high accuracy for 71 liquids with average absolute deviations (AADs) less than 5% and for 66 liquids with AADs less than 1%. These results are clearly better than the ones of other available correlations. This correlation can be directly used to estimate the value of the surface tension of the corresponding liquids at any temperature point from the triple point to the critical point. The accuracy of the predictions would clearly have economic benefits since it would allow improvement of process operating conditions, the development of new processes, the reduction of oversizing in the design of new equipment and even reduction of energy requirements.

Motivated by the recent work by G. Di. Nicola et al. [Fluid Phase Equilibria 417 (2016) 229], based on the DIPPR data for carboxylic acids, we here report a corresponding state based correlation for the temperature dependent surface tension of carboxylic acids fluids. Underneath the two reduced quantities defined here, the DIPPR data show a unique trend. It is found that the proposed correlation can be used for different subfamilies of the carboxylic acids, and can describe the DIPPR data with high accuracy with the absolute average deviation (AAD) less than 1% for 14 carboxylic acids, AAD

Correction for ‘Equations of the state of hard sphere fluids based on recent accurate virial coefficients B5–B12’ by Jianxiang Tian et al., Phys. Chem. Chem. Phys., 2019, 21, 13070–13077. DOI: 10.1039/C9CP02116G

Cadmium (Cd) generates a variety of physiological and ecological toxicity to spiders. However, little is known about the effects of Cd on symbiotic bacteria of spiders. Metatranscriptomics is increasing our knowledge of microorganisms in environment. To better understand the impact of Cd on the symbiotic bacteria of spiders, we generated and compared the metatranscriptomes of the intestinal microorganisms of Pardosa pseudoannulata with and without Cd stress. The community structure of intestinal microorganisms in P. pseudoannulata was composed of 4 kingdoms, namely bacteria, viruses, eukaryotes and archaea, including 46 phyla, 97 classes, 184 orders, 339 families, 470 genera, and 598 species. The abundance of eukaryotes, bacteria and viruses was decreased by 0.14%, 1.22% and 2.52% respectively while the archaea was increased by 99.16% when under Cd stress. We identified 1519 differentially expressed genes (DEGs), including 770 up-regulated and 749 down-regulated genes. The results of KEGG annotation revealed that the expression of genes that are involved in the carbon metabolism, protein and amino acid metabolism and synthesis, glucose metabolism, oxidative phosphorylation, and glutathione metabolism were influenced by Cd. Collectively, these findings showed that Cd significantly impacted the community structure and expression of related functional genes of intestinal microorganisms in P. pseudoannulata.

Fluorescent nucleobase analogs have attracted much attention in recent years due to their potential applications in nucleic acids research. In this work, four new size-expanded RNA base analogs were computationally designed and their structural, electronic, and optical properties are investigated by means of DFT calculations. The results indicate that these analogs can form stable Watson-Crick base pairs with natural counterparts and they have smaller ionization potentials and HOMO-LUMO gaps than natural ones. Particularly, the electronic absorption spectra and fluorescent emission spectra are calculated. The calculated excitation maxima are greatly red-shifted compared with their parental and natural bases, allowing them to be selectively excited. In gas phase, the fluorescence from them would be expected to occur around 526, 489, 510, and 462 nm, respectively. The influences of water solution and base pairing on the relevant absorption spectra of these base analogs are also examined.

A new kind of photoelectric hybrid current sensor is designed. The low-power current transformer (LPCT) is used as the primary sensor for current conversion. The optical fiber Fizeau interferometer acts as the secondary sensor for noncontact microvibration detection. An electro-dynamic structure works as a bridge connecting the two sensors. Using two different ways as frequency response analysis and linear fitting method, similar sensitivity results are obtained. It is considered to be 3.5152 nm/A when the current frequency is 50 Hz. When LPCT works at the rated primary current of 450 A, the maximum measurement ratio error and phase displacement are

Due to some similarity of innate immunity between insects and mammals, the study of the molecular mechanism of innate immunity in insects has become a focus of research. However, the exact molecular and cellular basis of immune system in insect remains poorly understood. Characterization of the transcriptomic response to Cd of spider is an effective approach to understanding the innate immunity mechanisms. In this study, we carried out transcriptome sequencing and gene expression analyses to develop molecular resources for Pardosa pseudoannulata venom glands with and without Cd treatments. A total of 92,778 assembled unigenes and 237 Cd stress-associated differentially expressed genes between the Cd-treated and control groups were obtained. Expression profile analysis demonstrated that immunity-related genes involved in bacterial invasion of epithelial cells, leukocyte transendothelial migration, platelet activation, apoptosis, phagosome, and Rap1 signaling pathway were upregulated by Cd exposure, except the genes involved in PPAR signaling pathway were downregulated. Our results provide the first comprehensive transcriptome dataset of venom glands in P. pseudoannulata response to Cd, which is valuable for throws light on the immunotoxicity mechanism of Cd, and the innate immunity complexity.

Many laboratory and field studies have been conducted on rice field spiders in China. There are 375 species, 108 genera, and 22 families of rice field spiders distributed within the major rice growing areas and 17 dominant species. The biological and ecological characteristics of 17 rice field spider species have been reported in detail. The biology and ecology of these species show significant differences among regions, farmland habitats, and agricultural practices. Future research should focus on rice field habitat diversity, enhancing the insecticide resistance of dominant spider populations, implementing large-scale breeding of spiders and augmentative release, breeding more leaf dominant species, conducting biosafety assessment of spiders in transgenic crops.

Several correlations between viscosity and surface tension for saturated normal fluids have been proposed in the literature. Usually, they include three or four adjustable coefficients for every fluid and give generally good results. In this paper we propose a new and improved four-coefficient correlation which was obtained by fitting data ranging from the triple point to a point very near to the critical one. Fifty four substances were considered, including simple fluids (such as rare gases), simple hydrocarbons, refrigerants, and some other substances such as carbon dioxide, water or ethanol. The new correlation clearly improves the results obtained with those previously available since it gives absolute average deviations below1% for 40 substances and below 2.1% for 10 substances more., Comment: 19 pages, 7 figures, 2 tables. arXiv admin note: text overlap with arXiv:1606.09105

A series of hetero-ring-expanded purine analogs are designed and their structural, electronic and excited-state properties are investigated by DFT calculations. The results indicate that the designed analogs can form stable base pairs with natural counterparts. Compared with natural ones, these size-expanded analogs and corresponding base pairs have smaller ionization potentials and HOMO–LUMO gaps. Furthermore, the A-analogs have ionization potentials even lower than natural G. Finally, the electronic absorption spectra are calculated and the nature of the low-lying excited states is discussed. These observations imply their promising applications as molecular wires and new DNA motifs.

By using the published accurate new virial coefficients B11∼B14 for the hard disk fluids [C. Zhang and B.M. Pettitt, Mol. Phys., 2014, 112, 1427], we here propose a new updated version of Tian-Gui-...

In this paper, we proposed a new one-parameter correlation for the surface tension of saturated fluids. This new correlation requires only the critical temperature as inputs and is tested by using the REFPROP data for 72 saturated fluids including refrigerants, alkanes and some other simple fluids such as argon, carbon dioxide, etc. It is found that this correlation well stands in the whole temperature range from the triple point to the critical point with high accuracy for 59 liquids with average absolute deviations (AADs) less than 5%, 50 liquids with AADs less than 3%, and 13 liquids with AADs less than 1%. These results are clearly better than those of the other available correlations. This correlation can be used to estimate the value of the surface tension of the corresponding liquids at any temperature point from the triple point to the critical point.

Based on the previous works [J. X. Tian, Y. X. Gui and A. Mulero, J. Phys. Chem. B 114, 13399 (2010); Phys. Chem. Chem. Phys. 12, 13597 (2010)], we constructed a new equation of state for the hard tetrahedron (HTH) fluid at stable state by using the recently published Monte Carlo simulation data [J. Kolafa and S. Labík, Mol. Phys. 113, 1119 (2015)]. It can reproduce the correct virial coefficients upto nine, which is the known highest order of virial coefficient for HTH fluid. It also describes the simulation data of the compressibility factor versus the packing fraction at stable state with high accuracy.

The interactions between a thieno-separated tricyclic guanine analog (ttG) and gold nanoclusters Au n ( n = 2, 4, 6, and 8) were studied theoretically at the DFT level. Geometries of neutral complexes were optimized using the B3LYP functional with the 6-31+G(d,p) basis set for ttG and the LANL2DZ basis set for gold clusters. The binding modes, interacting strength, and the charge transfer properties of different Au n –ttG complexes were investigated. Natural population analysis was performed for NBO charges. It was found that gold nanoclusters form stable complexes with ttG and the complexation results in a substantial amount of electronic charge being transferred from ttG to the gold clusters. Furthermore, binding of Au n is the most strong at N3 site, followed by the N7 site, and the binding at O6 site is relatively weaker. In addition, binding of Au n at N3 site will increase the planarity of ttG moiety. The vertical first ionization potential, electron affinity, fermi level, and the HOMO–LUMO gap of ttG and Au n –ttG complexes were also analyzed.

The ideal gas contribution to the isobaric heat capacity of fluids is a temperature dependent property which is commonly modelled as a polynomial expression. In this work, the performance and accuracy of the polynomial correlation proposed by Poling et al. in their well-known book is checked. To this end, the data accepted in the DIPPR database for 58 refrigerants were used. The mean average percentage deviations (MAPDs) obtained in the temperature range considered by Poling et al., usually up to 1000 K, are greater than 1.5% only for six refrigerants. We extended our study to the temperature range in which accepted DIPPR data are available (usually up to 1500 K), finding that only for four refrigerants can the Poling et al. correlation be used in this extended range. New coefficients for the correlation are given for the 58 refrigerants studied which reproduce the accepted DIPPR data. The new MAPD values are then below 1% for 49 refrigerants.

Design and synthesis of fluorescent nucleobase analogues for studying structures and dynamics of nucleic acids have attracted much attention in recent years. In the present work, a comprehensive theoretical study of electronic transitions of naphtho-homologated base analogues, namely, xxC, xxT, xxA, and xxG, was performed. The nature of the low-lying excited states was discussed, and the results were compared with those of x-bases. Geometrical characteristics of the lowest excited singlet ππ* states were explored using the CIS method. The calculated excitation maxima are 423, 397, 383, and 357 nm for xxA, xxG, xxC, and xxT, respectively, and they are greatly red-shifted compared with x-bases and natural bases, allowing them to be selectively excited in the presence of the natural bases. In the gas phase, the fluorescence from them would be expected to occur around 497, 461, 457, and 417 nm, respectively. The effects of methanol solution, deoxyribose, and base paring with their complementary natural bases on the relevant absorption and emission spectra of these modified bases were also examined.