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Nephrotoxicity caused by drug or chemical exposure involves different mechanisms and nephron segments as well as a complex temporal integration of injury and repair responses. Distinct cellular transcriptional programs regulate the time-dependent tissue injury and regeneration responses. Whole kidney transcriptome analysis cannot dissect the complex the nephron segment spatio- temporal injury and regeneration responses. Here, we used laser capture microdissection of formalin- fixed paraffin embedded sections followed by whole genome targeted RNA-sequencing-TempO-Seq and co-expression gene-network (module) analysis to determine the spatial-temporal responses in rat kidney glomeruli (GM), cortical proximal tubules (CPT) and outer-medulla proximal tubules (OMPT) comparison with whole kidney, after a single dose of the nephrotoxicant cisplatin. We demonstrate that cisplatin induced early onset of DNA damage in both CPT and OMPT, but not GM. Sustained DNA damage response was strongest in OMPT coinciding with OMPT specific inflammatory signaling, actin cytoskeletal remodeling and increased glycolytic metabolism coincident with suppression of mitochondrial activity. Later responses reflected regeneration-related cell cycle pathway activation and ribosomal biogenesis in the injured OMPT regions. Activation of modules containing kidney injury biomarkers was strongest in the OMPT, with OMPTCluexpression best correlating with urinary clusterin biomarker measurements compared the correlation of Kim1. Our findings also showed that whole kidney responses were less sensitive than OMPT. In conclusion, our LCM-TempO-Seq method reveals a detailed spatial mechanistic understanding of renal injury/regeneration after nephrotoxicant exposure and identifies the most representative mechanism-based nephron segment specific renal injury biomarkers.

For the technological integration of molecular switches in electronic devices, self-assembling nanomaterials of such switches are highly sought after. The syntheses of a new tetrapyridyl ligand bearing a C12 alkyl chain and two N-H bridges (compound 1) and of its iron(II) complex [Fe(1)(NCS)(2)] (compound 2), are described. Magnetic susceptibility data for bulk samples of 2 confirmed their gradual spin-crossover properties. The self-assembly of 1 and 2 on highly ordered pyrolytic graphite surfaces (HOPG) was investigated by Scanning Tunneling Microscopy (STM). Both compounds 1 and 2 formed ordered monolayers after deposition by drop casting. The patterns of the two compounds are very different, which is attributed to the fundamentally different hydrogen bonding networks before and after coordination of Fe(NCS)(2) to the tetradentate chelate. Two possible models for the self-assembly of 1 and 2 are provided. This work suggests that it is possible to design molecular switches that self-assemble on surfaces in highly ordered monolayer films. This is a significant step in the development of spin-switching materials, which may streamline the integration of molecular switches in for example memory and sensing devices.

In this paper, we present our solutions to the grand challenge task "Relation Understanding in Videos" in ACM Multimedia 2019. The challenge task aims to detect instances of target visual relations in a video, where a visual relation instance is represented by a relation triplet with the trajectories of the subject and object. It seems that it is similar to the image relation detection task with the input changed from images to videos. However, video relation detection requires a much more complex pipeline which not only needs to detect objects in each frame, but also track them in the temporal direction. In this challenge, we follow the basic pipeline structure which consists of 3 main separate components: an object detector, an object tracker and a relation predictor. Based on our analysis, there exist data unbalance and label missing problems in the VidOR dataset. We exploit two simple but effective methods to alleviate these problems. We also use trajectory Non-Maximum Suppression and a sliding window method to address the redundancy of trajectory proposals. Experimental results on the challenge task demonstrate that by applying these proposed approaches over the state-of-the-art relation prediction model, the video relation detection performance can be improved with the precision@1 and precision@5 reaching 0.3305 and 0.3507 respectively.

This study reports on the effects of zinc dilution on the structure and magnetic properties of the mononuclear two-step spin-crossover compound [Fe(bapbpy)(NCS)2] (1; bapbpy = N6,N6′-di(pyridin-2-yl)-2,2′-bipyridine-6,6′-diamine). The zinc analogue of 1, [Zn(bapbpy)(NCS)2] (3), was synthesized and characterized by X-ray powder diffraction, which suggests different structural features from 1. The crystal structure of the related compound [Fe(bapbpy)(NCS)]2[Zn(NCS)4]·3DMF (4) was determined by single-crystal X-ray diffraction. Unlike the hexacoordinate FeII in 1, the ZnII ions in 4 are pentacoordinate. Nine diluted powder samples [FexZn1–x(bapbpy)(NCS)2] were prepared with iron fractions of x = 0.89, 0.81, 0.76, 0.65, 0.60, 0.53, 0.44, 0.38, and 0.24. According to powder X-ray diffraction and infrared spectroscopy, the phase of compound 1 is retained in the zinc-diluted samples when x > 0.53. At higher dilutions (i.e., when x < 0.53), the phase of compound 3 gradually takes over, but the SCO of the iron complexes in the zinc phase remains observable at an iron fraction as low as x = 0.24. Powder X-ray diffraction and infrared spectroscopy data indicate the presence of the zinc phase only (i.e., compound 3) when x ≤ 0.24. Magnetic susceptibility measurements on the diluted samples show that upon decreasing the iron fraction x, both hysteresis cycles become initially narrower, and then vanish to lead to a single-step SCO material at x = 0.76. Upon additional increase of the zinc contents, the cooperativity of the SCO gradually vanishes to lead to a noncooperative SCO material at the lowest iron fraction studied (x = 0.24). Despite the different coordination properties of the bapbpy ligand towards FeII and ZnII, the spin crossover of the hexacoordinate FeII complex is robust enough to withstand dilution into a magnetically silent ZnII phase that is structurally different from that of the iron compound.

International audience; The spin transition in single crystals of the [FeII(bbpya) (NCS)2] (bbpya = N,N-bis(2–2′-bipyrid-6-yl)amine) mononuclear complex was investigated by a combination of X-ray diffraction, Raman spectroscopy, as well as optical and atomic force microscopy (AFM) methods. These studies, performed around 440 K, revealed an extremely abrupt spin transition associated with a structural phase transition from a triclinic (low spin) to a monoclinic (mixed low spin/high spin) structure. Spatially resolved observations of this transition evidenced a clear phase separation associated with heterogeneous nucleation and the formation of a moving macroscopic interface whose velocity reached in some cases 300 μm s–1. Using photothermal control it was possible to stabilize biphasic states of the crystal and then acquire AFM images of the phase boundary. A “sawtooth” like topography was repeatedly observed, which most likely emerges so as to minimize the elastic strain. Remarkably, a fine spatial control of the phase boundary could be also achieved using the AFM probe itself, through probe–sample convective heat exchange.

A series of iron(II) dithiocyanate complexes containing the tripodal ligands L, [Fe(L)(NCS)2] (with L = 6-Me2tmpa, 6-Me2pmea, 6-Me2-Me2uns-penp, 6-Me2-uns-penp, Me2uns-penp, imine-uns-penp and TMG-uns-penp), analogous to the known SCO complex[Fe(tmpa)(NCS)2] were prepared and investigated. It was possible to structurally characterize [Fe(6-Me2pmea)(NCS)2], [Fe(6-Me2-Me2uns-penp)(NCS)2], [Fe(Me2uns-penp)(NCS)2], [Fe(imine-uns-penp)(NCS)2] and [Fe(TMG-uns-penp)(NCS)2]. Magnetic susceptibility and Mosbauer measurements showed that all seven compounds maintain their high-spin states between 300 and 5 K.

The tetrapyridyl ligand bbpya (bbpya=N,N-bis(2,2′-bipyrid-6-yl)amine) and its mononuclear coordination compound [Fe(bbpya)(NCS)] (1) were prepared. According to magnetic susceptibility, differential scanning calorimetry fitted to Sorai's domain model, and powder X-ray diffraction measurements, 1 is low-spin at room temperature, and it exhibits spin crossover (SCO) at an exceptionally high transition temperature of T=418 K. Although the SCO of compound 1 spans a temperature range of more than 150 K, it is characterized by a wide (21 K) and dissymmetric hysteresis cycle, which suggests cooperativity. The crystal structure of the LS phase of compound 1 shows strong N-H⋯S intermolecular H-bonding interactions that explain, at least in part, the cooperative SCO behavior observed for complex 1. DFT and CASPT2 calculations under vacuum demonstrate that the bbpya ligand generates a stronger ligand field around the iron(II) core than its analogue bapbpy (N,N'-di(pyrid-2-yl)-2,2′-bipyridine-6,6′-diamine); this stabilizes the LS state and destabilizes the HS state in 1 compared with [Fe(bapbpy)(NCS)] (2). Periodic DFT calculations suggest that crystal-packing effects are significant for compound 2, in which they destabilize the HS state by about 1500 cm. The much lower transition temperature found for the SCO of 2 compared to 1 appears to be due to the combined effects of the different ligand field strengths and crystal packing., Funded by: COST action. Grant Number: CM1305.

We have investigated the spatio-temporal development of the spin transition in different single crystals of the molecular complex [Fe(bapbpy)(NCS)2] using optical microscopy. The thermal spin transition proceeds by nucleation at macroscopic defects, followed in most cases by anisotropic growth. We show that a lower crystalline quality leads to multi-site nucleation and intermittent spin transitions. We conclude that each crystal of a same spin crossover complex can have its proper spin transition kinetics depending on its crystalline properties and intrinsic microstructure.

et al., © 2014 American Chemical Society. Coordination of the ligand bapbpy (1, bapbpy = N,N′-di(pyrid-2-yl)-2,2′-bipyridine-6,6′-diamine), of one of its four dimethyl-substituted analogues 2-5 (R2bapbpy = N,N′-di(methylpyrid-2-yl)-2,2′-bipyridine-6,6′-diamine), or of one of its three bis(iso)quinoline analogues 6-8 (R2bapbpy= N,N′-di(quinolyl)-2,2′-bipyridine-6,6′-diamine), to Fe(NCSe)2, afforded eight new iron(II) compounds of the type [Fe(R2bapbpy)(NCSe)2] (9-16). Three of these compounds (11, 13, and 16) were structurally characterized by single crystal X-ray diffraction, which showed similar molecular geometry and packing compared to their thiocyanate analogues. Magnetic susceptibility measurements were carried out for all iron compounds and revealed thermal spin-crossover (SCO) behavior for compounds 9, 11, 13, 15, and 16. Compounds 11, 13, 15, and 16 show an increased transition temperature compared to the thiocyanate analogues. [Fe(bapbpy)(NCSe)2] (9) shows a gradual, one-step SCO, whereas its thiocyanate analogue [Fe(bapbpy)(NCS)2] is known for its cooperative two-step SCO. To discuss the influence of S-to-Se substitution on the cooperativity of the SCO, heat capacity measurements were carried out for compounds 9, 11, 13, 15, and 16, and fitted to the Sorai domain model. The number n of like-spin SCO centers per interacting domain, which is a quantitative measure of the cooperativity of the spin transition, was found to be high for compounds 11 and 15, and low for compounds 9, 11, and 13. Compound 15 is one of the few known SCO compounds that is more cooperative than its thiocyanate analogue. Altogether, X-ray diffraction, calorimetry, and magnetic data give a consistent structure-property relationship for this family of compounds: hydrogen-bonding networks made of intermolecular N-H⋯Se interactions are of paramount importance for the cooperativity of the SCO.

Micrometer-sized defects, induced by laser ablation, radically change the spatiotemporal dynamics of a first-order structural phase transition, in this case of a spin crossover material. This type of "domain engineering" is thus based on artificial defects, such as that in the image, which can serve either as nucleation sites or as pinning sites. The subsequent growth of the nucleated domains can also be guided to some extent.

11 páginas, 8 figuras, 4 tablas, 2 esquemas.-- et al., In this study, we show that 1) different isomers of the same mononuclear iron(II) complex give materials with different spin-crossover (hereafter SCO) properties, and 2) minor modifications of the bapbpy (bapbpy=N6,N6′-di(pyridin-2-yl)-2,2′-bipyridine-6,6′-diamine) ligand allows SCO to be obtained near room temperature. We also provide a qualitative model to understand the link between the structure of bapbpy-based ligands and the SCO properties of their iron(II) compounds. Thus, seven new trans-[Fe{R2(bapbpy)}(NCS)2] compounds were prepared, in which the R2bapbpy ligand bears picoline (9–12), quin-2-oline (13), isoquin-3-oline (14), or isoquin-1-oline (15) substituents. From this series, three compounds (12, 14, and 15) have SCO properties, one of which (15) occurs at 288 K. The crystal structures of compounds 11, 12, and 15 show that the intermolecular interactions in these materials are similar to those found in the parent compound [Fe(bapbpy)(NCS)2] (1), in which each iron complex interacts with its neighbors through weak NH⋅⋅⋅S hydrogen bonding and π–π stacking. For compounds 12 and 15, hindering groups located near the NH bridges weaken the NS intermolecular interactions, which is correlated to non-cooperative SCO. For compound 14, the substitution is further away from the NH bridges, and the SCO remains cooperative as in 1 with a hysteresis cycle. Optical microscopy photographs show the strikingly different spatio-temporal evolution of the phase transition in the noncooperative SCO compound 12 relative to that found in 1. Heat-capacity measurements were made for compounds 1, 12, 14, and 15 and fitted to the Sorai domain model. The number n of like-spin SCO centers per interacting domain, which is related to the cooperativity of the spin transition, was found high for compounds 1 and 14 and low for compounds 12 and 15. Finally, we found that although both pairs of compounds 11/12 and 14/15 are pairs of isomers their SCO properties are surprisingly different., Leiden Institute of Chemistry is kindly acknowledged for supporting this research.