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A type of fluorescent lignin ionic complexes is developed via the electrostatic complexation between ligninsulfonate and a tetraphenylethene-containing ammonium surfactant. These materials could be recyclable labeling biomaterials suitable for working at high temperatures and hydrophobic coating materials.

By forming a locked cis-state, the designed azobenzene-containing surfactant maintains the isotropic liquid state of DNA materials after ceasing UV light, which shows resistance to thermal and mechanical stimuli but sensitivity to Vis light.

A biomaterial with a photoregulated phase change showing a stable isotropic liquid state was developed by taking advantage of the van der Waals forces of cis-azobenzene.

Photoresponsive phase change materials (PPCMs) are capable of storing photon and heat energy simultaneously and releasing the stored energy as heat in a controllable way. While, the azobenzene-based PPCMs exhibit a contradiction between gravimetric energy storage density and photoinduced phase change. Here, a type of azobenzene surfactants with balance between molecular free volume and intermolecular interaction is designed in molecular level, which can address the coharvest of photon energy and low-grade heat energy at room temperature. Such PPCMs gain the total gravimetric energy density up to 131.18 J g

Development of photoliquefiable solid-state biomaterials at room temperature would address scientific challenges in life science. However, external stimuli-induced phase transitions are difficult for some biomacromolecules based materials, due to the high rigidity of these biomolecules. In this present work, by delicate molecule design on azobenzene-type ammonium surfactants, two new types of DNA-surfactant materials are fabricated. At room temperature, these DNA materials show photoliquefaction of ionic crystals to isotropic liquids under UV light, and fast self-assembly from isotropic liquids back to crystals after ceasing UV light, under the assistance of azobenzene isomerization. To achieve this objective, the designed solid-state DNA materials should have melting points near room temperature and an immediate liquid crystal to isotropic liquid transition process just above the melting points, which highly depends on the stoichiometric charge ratio between DNA and surfactants. As proved by the successful self-healing tests, these DNA ionic crystals are good biomaterials with potential applications in biomedicine and life science. This work would provide a new strategy for designing anhydrous functional biomaterials at room temperature by using rigid biomacromolecules. Statement of Significance At room temperature, solid-state biomaterials with photoregulated crystal⇄isotropic liquid phase transition property are attractive functional materials in life science, considering the body temperature and living environment temperature of human beings. Although several kinds of anhydrous materials achieved isothermal photoresponsive phase transitions, the photoregulated phase transition of anhydrous biomacromolecules based materials has not been achieved at room temperature, due to the high rigidity of these biomolecules. In this work, by delicate molecule design on ammonium surfactants, we synthesized two kinds of anhydrous DNA-surfactants ionic crystals. These DNA materials show fast photoliquefaction under UV light and self-assembly after ceasing light, which affords excellent self-healing biomaterials. This work would provide a new strategy for designing anhydrous photoresponsive biomaterials by using rigid biomacromolecules.

Solvent free DNA–surfactant melts are receiving continuous attractions in recent years. Their physical properties could be regulated via changing the alkyl chain length of surfactants. As an ideal external stimulus, light has been used in the regulation of mechanical properties of DNA thermotropic liquid crystal (TLC) containing an azobenzene motif, while in this case, the UV light is the only effective excitation source. However, in comparison with visible light, UV light causes damage to DNA and has low tissue-penetration efficiency problem. In this work, a new type of DNA–didodecyldimethylammonium bromide (DNA–DDAB) TLCs fabricating with gold nanoparticles (AuNPs) was demonstrated. The visible light-induced photothermal effect of AuNPs could change the mechanical properties of AuNPs/DNA–DDAB TLCs, as shown by clearly boundary motion activity and viscoelasticity change. Furthermore, the ratio of AuNPs and charge stoichiometry of DNA:DDAB also affected photocurrent generation property of these DNA melts. The development of this visible light responsive DNA melt might facilitate the related studies in biomedicine and biomaterials.

Solid-state spiropyrans would be excellent materials for solar energy storage, information storage, etc., if they could furnish the light-induced isomerization process at room temperature. However, solid-state spiropyrans with fully reversible photochromic properties at room temperature are extremely rare, due to the lack of sufficient free room for a photoisomerization process. The currently reported solid-state photochromic spiropyrans highly rely on the introduction of bulky rigid groups for creating the needed free room. In this work, via increasing the molecular flexibility, a new strategy for designing solid-state spiropyrans showing highly efficient reversible photochromism at room temperature has been developed. By attaching a flanking alkyl chain to the indole nitrogen, the as-prepared T-type spiropyrans exhibit fast photoresponsive properties. More attractively, this kind of spiropyran could be conveniently “evolved” into a new solid state showing advanced photochromic and thermochromic properties with three different colors. With good room temperature stability and excellent one-to-one correspondences between stimuli and colors, these solid-state spiropyrans are proved to be advanced information storage materials in our logic gate test. This work will provide a new strategy for designing advanced materials with solid-state photochromic molecules in low-molecular-weight.

Taking advantage of van der Waals forces, an azobenzene-containing surfactant with a stable

The functions of the materials composed of small molecules are highly dependent on their ordered molecular arrangements in both natural and artificial systems. Without ordered structure, small molecules hardly gain complicated functions, due to the absence of intermolecular covalent bond connection or strong network. Here, a low molecular weight spiropyran that could exhibit attractive photochromism and powerful adhesion property in disordered solid state is demonstrated. With maximum up to ∼8 MPa, the adhesion strength could be photoregulated in multiple levels, which also shows one-to-one correspondence to the specific color state. The working mechanism analysis on the photoregulated adhesion reveals that the isomer ratio of merocyanine form and the molecular packing density of spiropyran are the determining factors for the adhesion ability. The discovery of photoregulated adhesion from pure spiropyran provides a new strategy for developing functional materials by employing low molecular weight compounds.

In this paper, we study contact surgeries along Legendrian links in the standard contact 3-sphere. On one hand, we use algebraic methods to prove the vanishing of the contact Ozsv\'{a}th-Szab\'{o} invariant for contact $(+1)$-surgery along certain Legendrian two-component links. The main tool is a link surgery formula for Heegaard Floer homology developed by Manolescu and Ozsv\'{a}th. On the other hand, we use contact-geometric argument to show the overtwistedness of the contact 3-manifolds obtained by contact $(+1)$-surgeries along Legendrian two-component links whose two components are linked in some special configurations., Comment: 25 pages, 15 figures. Final version, accepted for publication in Quantum Topology

A completely water soluble azobenzene chemosensor 1 for selective detection of Hg2+ was synthesized. Taking advantage of the absorption changes corresponding to the transition moments polarized along the short axis of an azobenzene, 1 showed characteristic UV-Vis signal changes in the band around 240 nm for Hg2+ in wide pH ranges, which also showed good tolerance to various metal ions and photoirradiation. Upon addition of Hg2+ into the solution of 1, a favored formation of trans-1 was observed, which is attributed to an intramolecular coordination of the PEG chain and Nβ to Hg2+ confirmed by a control experiment test.

Oligonucleotides are widely used biological materials in the fields of biomedicine, nanotechnology, and materials science. Due to the demands for the photoregulation of DNA activities, scientists are placing more and more research interest in the interactions between reversible photochromic molecules and DNAs. Photochromic molecules can work as switches for regulating the DNAs' behavior under light irradiation; meanwhile, DNAs also exert influence over the photochromic molecules. The photochromic molecules can be attached to DNAs either by covalent bonds or by noncovalent forces, which results in different regulative functions. Azobenzenes, spiropyrans, diarylethenes, and stilbene-like compounds are important photochromic molecules working as photoswitches. By summarizing their interactions with oligonucleotides, this review intends to facilitate the relevant research on oligonucleotides/photochromic molecules in the biological and medicinal fields and in materials science.

Correction for ‘Photoregulative phase change biomaterials showing thermodynamic and mechanical stabilities’ by Lei Zhang et al., Nanoscale, 2022, 14, 976–983, https://doi.org/10.1039/D1NR06000G.

We introduce an Alexander polynomial for MOY graphs. For a framed trivalent MOY graph $\mathbb{G}$, we refine the construction and obtain a framed ambient isotopy invariant $\Delta_{(\mathbb{G},c)}(t)$. The invariant $\Delta_{(\mathbb{G}, c)}(t)$ satisfies a series of relations, which we call MOY-type relations, and conversely these relations determine $\Delta_{(\mathbb{G}, c)}(t)$. Using them we provide a graphical definition of the Alexander polynomial of a link. Finally, we discuss some properties and applications of our invariants., Comment: This version is accepted for publication in Selecta Mathematica. We thank the referee for careful reading and many helpful comments

We investigate the use of artificial neural networks (NNs) as an alternative tool to current analytical methods for recognizing knots in a given polymer conformation. The motivation is twofold. First, it is of interest to examine whether NNs are effective at learning the global and sequential properties that uniquely define a knot. Second, knot classification is an important and unsolved problem in mathematical and physical sciences, and NNs may provide insights into this problem. Motivated by these points, we generate millions of polymer conformations for five knot types: 0, 3_{1}, 4_{1}, 5_{1}, and 5_{2}, and we design various NN models for classification. Our best model achieves a five-class classification accuracy of above 99% on a polymer of 100 monomers. We find that the sequential modeling ability of recurrent NNs is crucial for this result, as it outperforms feed-forward NNs and successfully generalizes to differently sized conformations as well. We present our methods and suggest that deep learning may be used in specific applications of knot detection where some error is permissible. Hopefully, with further development, NNs can offer an alternative computational method for knot identification and facilitate knot research in mathematical and physical sciences.

Inspired by the combinatorial constructions in earlier work of the authors that generalized the classical Alexander polynomial to a large class of spatial graphs with a balanced weight on edges, we show that the value of the Alexander polynomial evaluated at $t=1$ gives the weighted number of the spanning trees of the graph., Comment: 13 pages. Comments are welcome

In this paper, we introduce a rational $$\tau $$ invariant for rationally null-homologous knots in contact 3-manifolds with nontrivial Ozsvath–Szabo contact invariants. Such an invariant is an upper bound for the sum of rational Thurston–Bennequin invariant and the rational rotation number of the Legendrian representatives of the knot. In the special case of Floer simple knots in L-spaces, we can compute the rational $$\tau $$ invariants by correction terms.

Soft thermotropic liquid crystals (TLCs) have advantages on processability and shape memory compared to hard solids and fluids. The development of photoswitchable soft TLCs based on biomolecules would afford reworkable shape information recording biomaterials for the areas requiring biocompatibility and degradability. In recent years, anhydrous DNA TLCs composed of DNA and ammonium surfactants have been receiving continuous attention. However, the photoswitchable phase transition has not been realized for soft DNA TLCs at room temperature, owing to the absence of functional ammonium surfactant. Herein, a new type of azobenzene-containing surfactant would be applied to the fabrication of soft DNA TLCs with photoresponsive physical properties. The double-chain design of the used surfactant and the use of DOAB as a dopant guarantee the soft state of DNA TLCs at r.t., which also facilitates the azobenzene isomerization by reducing the packing density of surfactants. With the assistance of photoisomerization of azobenzene, the reported DNA TLCs achieve reversible liquid crystal-isotropic liquid transition at temperatures below clearing points even at room temperature. The repeatable shape information recording and self-erasing tests indicate these DNA TLCs would be good shape information recording biomaterials in the future. This work also provides a useful strategy for designing photoresponsive soft biomaterials based on rigid biomolecules like DNA., Graphical abstract A new type of azobenzene-containing surfactant with good water solubility and flexibility is designed and synthesized for the fabrication of soft DNA thermotropic liquid crystals. By gaining reversible isothermal phase change ability at room temperature, the developed DNA materials exhibit effective shape information recording and self-erasing properties.Image 1

In this paper, we study distance one surgeries between lens spaces $L(p,1)$ with $p \geq 5$ prime and lens spaces $L(n,1)$ for $n \in \mathbb{Z}$ and band surgeries from $T(2,p)$ to $T(2,n)$. In particular, we prove that $L(n,1)$ is obtained by a distance one surgery from $L(5,1)$ only if $n=\pm 1$, $4$, $\pm 5$, $6$ or $\pm 9$, and $L(n,1)$ is obtained by a distance one surgery from $L(7,1)$ if and only if $n=\pm 1$, $3$, $6$, $7$, $8$ or $11$., 32 pages, 13 figures

Positive and negative charged stabilizing ligands, for example, ammonium surfactants and citrate, influence the catalytic activity of AuNPs greatly, due to their different electrostatic attraction ability with substrates. However, as for the more decisive factor in AuNPs catalyzed reactions, the free active surface sites of AuNPs influenced by different kinds of ammonium surfactants has not been studied yet. In this work, we prepared double chain and mono chain ammonium surfactants capped gold nanoparticles, DDAB-Au and CTAB-Au, and put them into the reduction reaction of uranine by NaBH4. Compared to CTAB-Au, DDAB-Au favors the adsorption of BH4− and generation of metal hydride on the active sites. As a result, DDAB-Au catalyzed reduction of uranine could give shorter induction time. We attribute this phenomenon to a weaker binding affinity of DDAB to the active sites of AuNPs, resulting from the more flexible, less polar and low charge-to-molecular weight ratio properties of DDAB. Fast responding time is one of important criteria in analytical chemistry and sensor chemistry. With dramatic fluorescence changes, some DDAB-Au catalyzed reactions would facilitate the related studies in the fields of catalysis, analysis and biosensors.

We prove a cabling formula for the concordance invariant ν + \nu ^+ , defined by the author and Hom in a previous work. This gives rise to a simple and effective four-ball genus bound for many cable knots.

Based on work of Rasmussen, we construct a concordance invariant associated to the knot Floer complex, and exhibit examples in which this invariant gives arbitrarily better bounds on the 4-ball genus than the Ozsvath-Szabo tau invariant.

We explicitly construct layered-triangulations for manifolds admitting a genus-one open book decomposition with connected binding. This construction gives an upper bound to the complexity of these manifolds. In a different direction, we show that the correction terms in Heegaard Floer homology give a lower bound to the genus of one-sided Heegaard splittings and the Z_2-Thurston norm. Using a result of Jaco–Rubinstein–Tillmann, this gives a lower bound to the complexity of certain closed 3-manifolds. We illustrate our theorems with some examples.

Although small molecules shed from pathogens are widely used to diagnose infection, such tests have not been widely implemented for tuberculosis. Here we show that the recently identified compound, 1-tuberculosinyladenosine (1-TbAd), accumulates to comprise >1% of all Mycobacterium tuberculosis lipid. Invitro and invivo, two isomers of TbAd weredetected that might serve as infection markers. Using mass spectrometry and nuclear magnetic resonance, we established the structure of the previously unknown molecule, N(6)-tuberculosinyladenosine (N(6)-TbAd). Its biosynthesis involves enzymatic production of 1-TbAd by Rv3378c followed by conversion to N(6)-TbAd via the Dimroth rearrangement. Intact biosynthetic genes are observed only within M.tuberculosis complex bacteria, and TbAd was not detected among other medically important pathogens, environmental bacteria, and vaccine strains. With no substantially similar known molecules in nature, the discovery and invivo detection of two abundant terpene nucleosides support their development as specific diagnostic markers of tuberculosis.

Background: Capillary microsampling (CMS) of 8 µl of blood provides a methodology that can be utilized for serial sampling in drug discovery mouse PK studies. Results: Blood CMS sample results were compared to plasma sample results for three compounds (with expected Cb/Cp of 1 to 2) and found to be similar. In addition, for three compounds, blood CMS results were found to be equivalent to results generated with standard whole blood sampling. In a 5-day repeated dose PK study, four mice were dosed (IV) daily and sampled on both day one and day five using blood CMS procedure. Conclusion: Blood CMS using 8 µl glass capillary microsamples provides a straightforward and effective approach for mouse serial blood sampling.

Given an element in the first homology of a rational homology 3-sphere $Y$, one can consider the minimal rational genus of all knots in this homology class. This defines a function $\Theta$ on $H_1(Y;\mathbb Z)$, which was introduced by Turaev as an analogue of Thurston norm. We will give a lower bound for this function using the correction terms in Heegaard Floer homology. As a corollary, we show that Floer simple knots in L-spaces are genus minimizers in their homology classes, hence answer questions of Turaev and Rasmussen about genus minimizers in lens spaces., Comment: 21 pages. V2: corrects a mistake in the proof of Proposition 1.5, incorporates the referee's comments

Based on the asymmetric copper-catalyzed 1,2-addition of Grignard reagents to ketones, (R,R,R)--tocopherol has been synthesized in 36% yield over 12 steps (longest linear sequence). The chiral center in the chroman ring was constructed with 73% ee by the 1,2-addition of a phytol-derived Grignard reagent to an -bromo enone prepared from 2,3-dimethylquinone.

A new asymmetric synthesis of dihydrofurans and cyclopentenols has been developed and is based on the copper-catalyzed 1,2-addition of Grignard reagents to enones in combination with Sonogashira coupling/cyclization or ring-closing metathesis. By this approach, dihydrofurans with an oxygen-containing tertiary stereocenter and chiral tertiary cyclopentenols are efficiently prepared. The absolute stereochemistry of the products has been established.

Two Dehn surgeries on a knot are called {\it purely cosmetic}, if they yield manifolds that are homeomorphic as oriented manifolds. Suppose there exist purely cosmetic surgeries on a knot in $S^3$, we show that the two surgery slopes must be the opposite of each other. One ingredient of our proof is a Dehn surgery formula for correction terms in Heegaard Floer homology., Comment: v2: 19 pages, incorporates referee's comments

We show that two Dehn surgeries on a knot $K$ never yield manifolds that are homeomorphic as oriented manifolds if $V_K''(1)\neq 0$ or $V_K'''(1)\neq 0$. As an application, we verify the cosmetic surgery conjecture for all knots with no more than $11$ crossings except for three $10$-crossing knots and five $11$-crossing knots. We also compute the finite type invariant of order $3$ for two-bridge knots and Whitehead doubles, from which we prove several nonexistence results of purely cosmetic surgery., Comment: 13 pages, 4 figures

Talosin A and B, namely genistein 7-O-alpha-L-6-deoxy-talopyranoside and genistein 4`,7-di-O-alpha-L-6-deoxytalopyranoside, which show excellent antifungal and anti-inflammatory activities, were synthesized concisely.

Mangiferin, isomangiferin, and homomangiferin, the xanthone C-glycosides with a wide spectrum of pharmacological effects, were synthesized concisely, featuring a C-glycosylation of a xanthene derivative with perbenzylglucopyranosyl N-phenyltrifluoroacetimidate.

Background: Serial sampling in discovery rat PK studies could be performed via capillary microsampling (CMS) of blood or by using the Mitra™ device to collect dried blood samples. Results: Blood CMS results were compared with Mitra sampling results for four test compounds dosed in rat PK studies. The PK profiles obtained from CMS sampling were found to be very similar to those obtained from the Mitra sampling. For 15-µl blood CMS samples, freezing before the dilution step was found to be acceptable. Conclusion: Blood CMS using 15-µl glass capillary microsamples works well for serial blood sampling in rat PK studies. The Mitra microsampling device provides an alternative method for collecting 10 µl of blood as a dried blood sample.

Introduction Serial sampling methods have been used for rat pharmacokinetic (PK) studies for over 20 years. Currently, it is still common to take 200–250 μL of blood at each timepoint when performing a PK study in rats and using serial sampling. While several techniques have been employed for collecting blood samples from rats, there is only limited published data to compare these methods. Recently, microsampling (≤ 50 μL) techniques have been reported as an alternative process for collecting blood samples from rats. Methods In this report, five compounds were dosed orally into rats. For three proprietary compounds, jugular vein cannula (JVC) sampling was used to collect whole blood and plasma samples and capillary microsampling (CMS) was used to collect blood samples from the tail vein of the same animal. For the two other compounds, marketed drugs fluoxetine and glipizide, JVC sampling was used to collect both whole blood and blood CMS samples while tail-vein sampling from the same rats was also used to collect both whole blood and blood CMS samples. Results For the three proprietary compounds, the blood AUC as well as the blood concentration-time profile that were obtained from the tail vein were different from those obtained via JVC sampling. For fluoxetine, the blood total exposure (AUC) was not statistically different when comparing tail-vein sampling to JVC sampling, however the blood concentration-time profile that was obtained from the tail vein was different than the one obtained from JVC sampling. For glipizide, the blood AUC and concentration-time profile were not statistically different when comparing the tail-vein sampling to the JVC sampling. For both fluoxetine and glipizide, the blood concentration profiles obtained from CMS were equivalent to the blood concentration profiles obtained from the standard whole blood sampling, collected at the same sampling site. Discussion The data in this report provide strong evidence that blood CMS is a valuable small volume blood sampling approach for rats and that it provides results for test compound concentrations that are equivalent to those obtained from traditional whole blood sampling. The data also suggest that for some compounds, the concentration-time profile that is obtained for a test compound based on sampling from a rat tail vein may be different from that obtained from rat JVC sampling. In some cases, this shift in the concentration-time profile will result in different PK parameters for the test compound. Based on these observations, it is recommended that a consistent blood sampling method should be used for serial microsampling in discovery rat PK studies when testing multiple new chemical entities. If the rat tail vein sampling method is selected for PK screening, then conducting a bridging study on the lead compound is recommended to confirm that the rat PK obtained from JVC sampling is comparable to the tail-vein sampling.

A new asymmetric synthesis of dihydrofurans and cyclopentenols has been developed and is based on the copper-catalyzed 1,2-addition of Grignard reagents to enones in combination with Sonogashira coupling/cyclization or ring-closing metathesis. By this approach, dihydrofurans with an oxygen-containing tertiary stereocenter and chiral tertiary cyclopentenols are efficiently prepared. The absolute stereochemistry of the products has been established.

Using the mapping cone of a rational surgery, we give several obstructions for Seifert fibered surgeries, including obstructions on the Alexander polynomial, the knot Floer homology, the surgery coefficient and the Seifert and four-ball genus of the knot., 13 pages

Let [math] be a nontrivial knot in [math] , and let [math] and [math] be two distinct rational numbers of same sign. We prove that there is no orientation-preserving homeomorphism between the manifolds [math] and [math] . We further generalize this uniqueness result to knots in arbitrary L–space homology spheres.

In this paper, we write down a special Heegaard diagram for a given product three manifold $\Sigma_g\times S^1$. We use the diagram to compute its perturbed Heegaard Floer homology., Comment: 12 pages, 6 figures

We classify left invariant metrics with nonnegative curvature on SO(3) and U(2)., Comment: 1 figure