No abstract

Topology is a universal concept that is encountered in daily life and is known to determine many static and dynamical properties of matter. Taming and controlling the topology of materials therefore constitutes a contemporary interdisciplinary challenge. Building on the controllable spatial properties of soft matter appears as a relevant strategy to address the challenge, in particular, because it may lead to paradigmatic model systems that allow checking theories experimentally. Here we report experimentally on a wealth of complex free-standing metastable topological architectures at the micron scale, in frustrated chiral nematic droplets. These results support recent works predicting the formation of free-standing knotted and linked disclination structures in confined chiral nematic fluids. We also demonstrate that various kinds of external fields (thermal, electrical and optical) can be used to achieve topological remote control. All this may foster the development of new devices based on topologically structured soft media.

Molecular machines operated by light have been recently shown to be able to produce oriented motion at the molecular scale as well as do macroscopic work when embedded in supramolecular structures. However, any supramolecular movement irremediably ceases as soon as the concentration of the interconverting molecular motors or switches reaches a photo-stationary state. To circumvent this limitation, researchers have typically relied on establishing oscillating illumination conditions-either by modulating the source intensity or by using bespoke illumination arrangements. In contrast, here we report a supramolecular system in which the emergence of oscillating patterns is encoded at the molecular level. Our system comprises chiral liquid crystal structures that revolve continuously when illuminated, under the action of embedded light-driven molecular motors. The rotation at the supramolecular level is sustained by the diffusion of the motors away from a localized illumination area. Above a critical irradiation power, we observe a spontaneous symmetry breaking that dictates the directionality of the supramolecular rotation. The interplay between the twist of the supramolecular structure and the diffusion of the chiral molecular motors creates continuous, regular and unidirectional rotation of the liquid crystal structure under non-equilibrium conditions.

Abstract. The urinary proteome in health and disease attracts increasing attention because of the potential diagnostic and pathophysiologic biomarker information carried by specific excreted proteins or their constellations. This cross-sectional study aimed to analyze the urinary proteome in patients with biopsy-proven acute rejection (n ϭ 23) compared with transplant recipients with stable graft function (n ϭ 22) and healthy volunteers (n ϭ 20) and to correlate this with clinical, morphologic, and laboratory data. Urine samples were preadsorbed on four different protein chip surfaces, and the protein composition was analyzed using a surface-enhanced laser desorption/ionization time-of-flight mass spectrometer platform. The data were analyzed using two independent approaches to sample classification. Patients who experienced acute rejection could be distinguished from stable patients with a sensitivity of 90.5 to 91.3% and a specificity of 77.2 to 83.3%, depending on the classifier used. Protein masses that were important in constructing the classification algorithms included those of mass 2003.0, 2802.6, 4756.3, 5872.4, 6990.6, 19,018.8, and 25,665.7 Da. Normal urine was distinguished from transplant urine using a protein marker of mass 78,531.2 Da with both a sensitivity and a specificity of 100%. In conclusion, (1) urine proteome in transplant recipients with stable graft function was significantly different from healthy control subjects, and (2) acute rejections were characterized by a constellation of excreted proteins. Analysis of the urinary proteome may expedite the noninvasive prediction of acute graft rejection, thus importantly assisting in establishing the diagnosis.

We previously demonstrated that 4.7 kDa and 4.4 kDa peptides are useful in diagnosing acute rejection in renal transplant recipients. The aim of this study was to characterize these polypeptides and assess their potential as biomarkers. In conclusion, the ratio of b -Defensin-1 and a -1-antichymotrypsin excretion in the urine is a novel, potentially useful candidate biomarkers of acute rejection.

The pathogenesis of progressive renal allograft injury, which is termed chronic allograft nephropathy (CAN), remains obscure and is currently defined by histology. Prospective protocolbiopsy trials have demonstrated that clinical and standard laboratory tests are insufficiently sensitive indicators of the development and progression of CAN. The study aim was to determine if CAN could be characterized by urinary proteomic data and identify the proteins associated with disease. The urinary proteome of 75 renal transplant recipients and 20 healthy volunteers was analyzed using surface enhanced laser desorption and ionization MS. Patients could be classified into subgroups with normal histology and Banff CAN grades 2-3 with a sensitivity of 86% and a specificity of 92% by applying the classification algorithm Adaboost to urinary proteomic data. Several urinary proteins associated with advanced CAN were identified including α1-micro-globulin, β2-micro-globulin, prealbumin, and endorepellin, the antiangiogenic C-terminal fragment of perlecan. Increased urinary endorepellin was confirmed by ELISA and increased tissue expression of the endorepellin/perlecan ratio by immunofluoresence analysis of renal biopsies. In conclusion, analysis of urinary proteomic data has further characterized the more severe CAN grades and identified urinary endorepellin, as a potential biomarker of advanced CAN.

The response to steroid therapy is used to characterize the idiopathic nephrotic syndrome (INS) of childhood as either steroid-sensitive (SSNS) or steroid-resistant (SRNS), a classification with a better prognostic capability than renal biopsy. The majority (∼80%) of INS is due to minimal change disease but the percentage of focal and segmental glomerulosclerosis is increasing. We applied a new technological platform to examine the urine proteome to determine if different urinary protein excretion profiles could differentiate patients with SSNS from those with SRNS. Twenty-five patients with INS and 17 control patients were studied. Mid-stream urines were analyzed using surface enhanced laser desorption and ionization mass spectrometry(SELDI-MS). Data were analyzed using multiple bioinformatic techniques. Patient classification was performed using Biomarker Pattern Software^TM and a generalized form of Adaboost and predictive models were generated using a supervised algorithm with cross-validation. Urinary proteomic data distinguished INS patients from control patients, irrespective of steroid response, with a sensitivity of 92.3%, specificity of 93.7%, positive predictive value of 96% and a negative predictive value of 88.2%. Classification of patients as SSNS or SRNS was 100%. A protein of mass 4,144 daltons was identified as the single most important classifier in distinguishing SSNS from SRNS. SELDI-MS combined with bioinformatics can identify different proteomic patterns in INS. Characterization of the proteins of interest identified by this proteomic approach with prospective clinical validation may yield a valuable clinical tool for the non-invasive prediction of treatment response and prognosis.

light into work and power by soft polymer machines has been demonstrated also. [17] Light-responsive cholesteric liquid crystals can be prepared by dissolving a small percentage of chiral photoswitches in a (achiral) nematic liquid crystal host [4,18] (Figure 1). The propensity of these photoswitches, used as dopants, to induce a twist in a given host is characterized by their helical twisting power (HTP), defined as β = × × − ( ) 1 p c ee , where p is the pitch and corresponds to a full 360° rotation of the molecules along the helical axis, c is the concentration of the dopant in wt%, and ee is the enantiomeric excess of the dopant. Chiral switches are typically characterized by large twisting powers for their chirality and can be amplified across length scales effectively. [6] Azobenzenes are typically used as switchable dopants because their trans-cis photoisomerization is associated with large changes in both the geometry and the dipole moment of the molecule. While rod-like trans-azobenzenes are compatible with the nematic order, the bent-like cis-molecules disturb this molecular order significantly. Consequently, the HTP of the trans and the cis isomers are remarkably different. Moreover, coupling azobenzenes to elements of axial chirality yields both a large HTP in the ground state and a large variation of HTP under irradiation with light, compared to chiral azobenzenes that display point chirality only. [11,[19][20][21][22] Light-driven helix inversion has also been reported, when chiral azobenzene dopants with axial chirality were used as dopants. [23][24][25] However, the lack of thermal stability of the cisisomer remains a limitation to reaching the full potential of complex dynamic behavior in these supramolecular systems.Fluorinated azobenzenes display larger thermal stability than their classical counterparts, primarily because the repulsion between the nitrogen lone pairs that destabilizes the cis-isomer is lifted by electron-withdrawing effect of the fluorine atoms in ortho-position. [26][27][28][29] Here, we combine the axial chirality of a binaphthyl moiety with ortho-fluorination of an azobenzene moiety in molecular photoswitches that induce supramolecular helices in liquid crystals in both forms, and thus we demonstrate the photoengineering of long-lived supramolecular helices in soft matter. Results and DiscussionMolecules 1a and 1b were synthesized from commercially available starting materials. Their photochemistry and performance as dopants were investigated by comparing them to the reference azobenzenes 2a [19] and 2b [20,30] in the same Molecular PhotoswitchesChiral azobenzenes can be used as photoswitchable dopants to control supramolecular helices in liquid crystals. However, the lack of thermal stability of the cis-isomer precludes envisioning the generation of long-lived supramolecular helices with light. Here, this study demonstrates thermally stable and axially chiral azobenzene switches that can be used as chiral dopants to create supramolecular helices from (achiral) nematic liq...