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International audience; Local mechanical properties of submicron features are of particular interest due to their influence on macroscopic material performance and behaviour. This study is focused on local nanomechanical measurements, based on the latest Atomic Force Microscopy (AFM) mode, where the peak force set point is finely controlled at each pixel. After probe calibration, we evaluate the impact of spring constant of two AFM hand-crafted natural full diamond tips with steel cantilevers, used for mapping. Based on the fast capture of the cantilever deflection at each pixel and real time force curve analysis in the elastic region, AFM local measured contact moduli mappings of the silica beads ('50 GPa) incorporated in an epoxy resin matrix, are compared with those determined using classical instrumented nanoindentation tests. Our analyses show that with the two AFM probes, without local residual deformation, the high moduli of the silica beads measured with this advanced AFM mode are within the standard deviation of the values determined by classical nanoindentation. Lay Description: The knowledge of material properties at the nanometer scale is a key parameter for well understanding and determining the behavior of material at macroscopic scale. In this paper, we compare two methods (an advanced mode and a classical one) based on the analysis of probes in interaction with the surface of studied material. We focus on a latest developed mode for determining local mechanical properties with a very high spatial resolution. For the advanced mode, we also consider two different hand-crafted probes. Our analyses show that with the high spatial resolution advanced mode, local mechanical properties are well determined. We also highlight the impact of the properties of the used probes for this advanced mode. In a final step, the power of the presented investigation lies in the fact that it does not modify the topography of the surface.

Talaromyces islandicus ('Penicillium islandicum') is a widespread foodborne mold that produces numerous secondary metabolites, among them potent mycotoxins belonging to different chemical classes. A notable metabolite is the hepatotoxic and carcinogenic pentapeptide cyclochlorotine that contains the unusual amino acids β-phenylalanine, 2-aminobutyrate and 3,4-dichloroproline. Although the chemical structure has been known for over five decades, nothing is known about the biosynthetic pathway of cyclochlorotine. Bioinformatic analysis of the recently sequenced genome of T. islandicus identified a wealth of gene clusters potentially coding for the synthesis of secondary metabolites. Here, we show by RNA interference-mediated gene silencing that a nonribosomal peptide synthetase, CctN, is responsible for the synthesis of cyclochlorotine. Moreover, we identified novel cyclochlorotine chemical variants, whose production also depended on cctN expression. Surprisingly, the halogenase required for cyclochlorotine biosynthesis is not encoded in the cct cluster. Nonetheless, our findings enabled us to propose a detailed model for cyclochlorotine biosynthesis. In addition, comparative genomics revealed that cct-like clusters are present in all of the sequenced Talaromyces strains indicating a high prevalence of cyclochlorotine production ability.

Background Correction of prominent ears is a common plastic surgical procedure. The laser-assisted cartilage reshaping (LACR) technique for protruding ears was developed at the French National Institute of Health and Medical Research in Lille, France, using both the 1064- and 1540-nm wavelengths, with a view to simplifying the surgical procedure. Herein we report our results with the 1064-nm wavelength. Methods Between 2008 and 2010, twenty-six 1064-nm LACR procedures in 14 patients were performed. Twelve patients received treatment to both ears, and 2 patients received treatment to one ear. Each procedure consisted of a single treatment session. The treatment consisted of laser irradiation of both sides of the helix with single pulses of 70 J/cm2. The beam diameter was 6 mm. Early and late complications were defined and reviewed for all patients. Satisfaction was assessed by patients using a visual analogue scale from 0 (unsatisfied) to 20 (highly satisfied). The superior and middle cephaloauricular distances were prospectively evaluated at 6 months after treatment. Results Complications included eight cases of localized skin burns and one case of dermatitis. The mean right/left superior and middle cephaloauricular distances were 10.5 ± 1.5 mm/10.7 ± 1.0 mm and 16.3 ± 2.2 mm/16.3 ± 2.8 mm, respectively, as compared to 17.5 ± 2.9 mm/18.6 ± 2.5 mm (P

Objectives/Hypothesis In 2006, our institute reported the first clinical use of laser-assisted cartilage reshaping (LACR) for protruding ears. Since then, the technique has been developed and refined. This article reviews the literature on the clinical application of LACR. Study Design Literature review. Methods A MEDLINE literature search was performed on LACR combined with cross-referencing. The period of search was 1993 to 2014. Search terms used were: laser, cartilage reshaping, protruding ears, LACR. Results Only seven clinical studies using three different wavelengths were found in the literature: 1,064 nm (Nd:YAG), 10,600 nm (CO2), and 1540 nm (Er:Glass). Clinical outcomes, laser wavelength and parameters, and patient satisfaction are discussed in each case. Conclusions The success rate for ear reshaping achieved with LACR appears promising. The use of this noninvasive technique will increase in the near future. Level of Evidence Laryngoscope, 125:2067–2071, 2015

To design high-performance poly(lactide)-based materials (PLA-based) with improved toughness, two approaches based on the reactive extrusion (REx) process are investigated and compared in the present study. The first approach relies upon a two-step procedure using a REx-polymerized poly(ethylene glycol) methyl ether acrylate, i.e., poly(AcrylPEG), as a highly-branched and compatible impact modifier for PLA. The free-radical polymerization proves to be very efficient with a peroxide initiator concentration of 1 wt%. The as-produced poly(AcrylPEG) is then melt-blended with PLA by extrusion. The resulting materials exhibit largely increase impact resistance (ca. 35 kJ/m2) in presence of 20 wt% poly(AcrylPEG) in comparison with neat PLA (2.7 kJ/m2), while moderate ductility (tensile elongation at break

The co-addition of rubber-like poly(e-caprolactone-co-D, l-lactide) (P[CL-co-LA]) as impact modifier and N,N′-ethylenebis(stereamide) (EBS) as nucleating agent has here been investigated to tailor both the crystallization and toughness of resulting polylactide (PLA)-based materials. In this work, 10 wt% of P[CL-co-LA] copolymer and different concentrations of EBS were added into PLA by twin-screw extrusion (in a micro-compounder) in order to establish the mechanical performances of the resulting blends upon the nucleating agent content. Crystallization behavior and impact toughness of PLA-based materials were both enhanced and were ascribed to a clear alteration of the matrix crystallinity, spherulitic growth rate, and crystal structure upon the nucleating agent content. As a result, toughness of PLA-based materials was considerably enhanced up to, at least, 11 times with respect to neat PLA. Such improvement of the fracture resistance upon the extent of PLA crystallinity was related to a change in the toughening mechanism from crazing to shear-yielding (combined with crazing) through the deformation of spherulites, promoting high energy dissipation pathways as crystallization occurs. Copyright © 2015 John Wiley & Sons, Ltd.

Introduction Hyperhidrosis is a debilitating problem that is not only uncomfortable and inconvenient, but also embarrassing in work and social situations. In spite of the availability of several options for the treatment of axillary hyperhidrosis, recently, there has been an increasing interest in the use of laser therapy. This study aims to evaluate the efficacy of a laser diode device emitting at wavelengths of 924 and 975 nm and classical curettage either alone, simultaneously or in combination. Material and methods A randomized prospective controlled trial was carried out on 100 patients divided into four groups, each with a different protocol: Laser alone at 975 nm (group 1), laser alone at 924/975 nm simultaneously (group 2), curettage alone (group 3), and finally laser at 924/975 nm followed by curettage (group 4). HDSS, starch test and GAIS were used to assess treatment efficacy. The follow-up extended to one year. Statistical analysis (SPSS) was used to determine the accuracy of the results. Result Two patients of group 1 experienced burns during treatment, which took over a month to heal. This group of patients achieved the worst results: The starch test scale results after treatment were 2.48 ± 0.51 and 2.76 ± 0.44 (at 1 and 12 months). The GAIS results were 1.04 ± 0.35 and 0.92 ± 0.28 (1 and 12 months). In group 2 the starch test scale results after treatment were 1.36 ± 0.49 and 1.48 ± 0.51 (at 1 and 12 months). The GAIS results were 2.36 ± 0.49 and 2.72 ± 0.46 (at 1 and 12 months). In group 3, the starch test scale results after treatment were 1.56 ± 0.51 and 1.76 ± 0.60 (at 1 and 12 months), which corresponds to small to substantially smaller dark areas. The GAIS results were 2.28 ± 0.46 and 2.64 ± 0.49 (at 1 and 12 months). The best results were obtained in group 4: HDSS scores were reduced from 3.88 ± 0.33 before treatment to 1.24 ± 0.44 and 0.48 ± 0.51 at the 1 and 12 months controls. The starch test scale results after treatment were 0.40 ± 0.50 and 0.44 ± 0.51 (at 1 and 12 months). The GAIS results were 3.72 ± 0.54 and 3.76 ± 0.44 (at 1 and 12 months). Conclusion In this study, the laser at 924/975 nm combined with curettage was determined to be the optimal treatment option of those tested for axillary hyperhidrosis. This treatment was safe, with few side effects and improvement that persisted to one year follow-up. Lasers Surg. Med. 47:173–179, 2015. © 2015 Wiley Periodicals, Inc.

Summary Aims Brivaracetam (BRV) is an antiepileptic drug in Phase III clinical development. BRV binds to synaptic vesicle 2A (SV2A) protein and is also suggested to inhibit voltage-gated sodium channels (VGSCs). To evaluate whether the effect of BRV on VGSCs represents a relevant mechanism participating in its antiepileptic properties, we explored the pharmacology of BRV on VGSCs in different cell systems and tested its efficacy at reducing the sustained repetitive firing (SRF). Methods Brivaracetam investigations on the voltage-gated sodium current (INa) were performed in N1E-155 neuroblastoma cells, cultured rat cortical neurons, and adult mouse CA1 neurons. SRF was measured in cultured cortical neurons and in CA1 neurons. All BRV (100–300 μM) experiments were performed in comparison with 100 μM carbamazepine (CBZ). Results Brivaracetam and CBZ reduced INa in N1E-115 cells (30% and 40%, respectively) and primary cortical neurons (21% and 47%, respectively) by modulating the fast-inactivated state of VGSCs. BRV, in contrast to CBZ, did not affect INa in CA1 neurons and SRF in cortical and CA1 neurons. CBZ consistently inhibited neuronal SRF by 75–93%. Conclusions The lack of effect of BRV on SRF in neurons suggests that the reported inhibition of BRV on VGSC currents does not contribute to its antiepileptic properties.

Pseudomonas CMR12a is a biocontrol strain that produces phenazine antibiotics and as yet uncharacterized cyclic lipopeptides (CLPs). The CLPs of CMR12a were studied by chemical structure analysis and in silico analysis of the gene clusters encoding the nonribosomal peptide synthetases responsible for CLP biosynthesis. CMR12a produces two different classes of CLPs: orfamides B, D and E, whereby the latter two represent new derivatives of the orfamide family, and sessilins A-C. The orfamides are made up of a 10 amino acid peptide coupled to a β-hydroxydodecanoyl or β-hydroxytetradecanoyl fatty acid moiety, and are related to orfamides produced by biocontrol strain P. protegens Pf-5. The sessilins consist of an 18 amino acid peptide linked to a β-hydroxyoctanoyl fatty acid, and differ in one amino acid from tolaasins, toxins produced by the mushroom pathogen P. tolaasii. CLP biosynthesis mutants were constructed and tested for biofilm formation and swarming motility. Orfamides appeared indispensable for swarming, while sessilin mutants showed reduced biofilm formation, but enhanced swarming motility. The interplay between the two classes of CLPs fine-tunes these processes. The presence of sessilins in wild type CMR12a interferes with swarming by hampering the release of orfamides and by co-precipitating orfamides to form a white-line-in agar.

Objectives/Hypothesis The purpose of this study was to analyze our experience with the composed double skin paddle fibula free flap to reconstruct large mandibulofacial defects. Study Design Between 2006 and 2011, a total of 32 composed double skin paddle fibula free flap procedures were performed on 32 patients (mean age 54.4 ± 9.7 years, mean follow-up period of 3.4 ± 1.7 years). Methods A chart review was drawn up to determine the type of defects covered by each skin paddle, the vascular anatomy, the origin of the perforators, and any associated complications. Results The distal septocutaneous skin paddle (Nakajima type B) was used for the reconstruction of the floor of the mouth in most cases. The proximal paddle (Nakajima type D) was used for base of the tongue, mobile tongue, soft palate, internal cheek, inferior lip, and the skin of the chin and neck. The lateral soleus pedicle arose from the fibular pedicle in 28 cases and directly from the tibial-fibular trunk in four cases. There were two partial soleus skin paddle losses. Seven complications required revision surgery: due to a cervical abscess in two cases, due to a hematoma in two cases, due to a disunion of the second skin paddle leading to an orostoma in two cases, and due to an exposition of the osteosynthesis material in one case. Conclusion In large mandibulofacial defects, a second skin paddle raised on the soleus perforators may be of benefit when reconstructing the soft palate, neck, cheek, or tongue as the length of its pedicle renders a second free flap unnecessary. Level of Evidence IV. Laryngoscope, 124:1336–1343, 2014

Magnetic resonance imaging (MRI) offers the possibility of tracking cells labelled with a contrast agent and evaluating the progress of cell therapies. This requires efficient cell labelling with contrast agents. A basic incubation of cells with iron oxide nanoparticles (NPs) is a common method. This study reports the synthesis at the gram scale of iron oxide nanoparticles as MRI T2 contrast agents for cell labelling. These NPs are based on small iron oxide cores coated with a thin polysiloxane shell presenting carboxylic acid functions. The iron oxide cores produced have been characterized by transmission electron microscopy, X-ray diffraction, ζ-potential, infrared, photon correlation spectroscopy, atomic force microscopy, magnetometry and relaxometric measurements. These measurements confirmed the expected surface modification by carboxysilane. Carboxylic groups created electrostatic repulsion between NPs when they are deprotonated. Therefore, highly concentrated aqueous solutions of carboxysilane coated iron oxide NPs can be obtained, up to 70% (w/w). These NPs could be used for cell labelling owing to their aggregation and re-dispersion properties. NPs precipitated in Dulbecco's modified Eagle medium induced a rapid association with 3 T6 fibroblast cells and could easily be re-dispersed in phosphate buffer saline solution to obtain properly labelled cells. Copyright © 2013 John Wiley & Sons, Ltd.

Many antiepileptic drugs (AEDs) exert their therapeutic activity by modifying the inactivation properties of voltage-gated sodium (Na(v) ) channels. Lacosamide is unique among AEDs in that it selectively enhances the slow inactivation component. Although numerous studies have investigated the effects of AEDs on Na(v) channel inactivation, a direct comparison of results cannot be made because of varying experimental conditions. In this study, the effects of different AEDs on Na(v) channel steady-state slow inactivation were investigated under identical experimental conditions using whole-cell patch-clamp in N1E-115 mouse neuroblastoma cells. All drugs were tested at 100 μM, and results were compared with those from time-matched control groups. Lacosamide significantly shifted the voltage dependence of Na(v) current (I(Na) ) slow inactivation toward more hyperpolarized potentials (by -33 ± 7 mV), whereas the maximal fraction of slow inactivated channels and the curve slope did not differ significantly. Neither SPM6953 (lacosamide inactive enantiomer), nor carbamazepine, nor zonisamide affected the voltage dependence of I(Na) slow inactivation, the maximal fraction of slow inactivated channels, or the curve slope. Phenytoin significantly increased the maximal fraction of slow inactivated channels (by 28% ± 9%) in a voltage-independent manner but did not affect the curve slope. Lamotrigine slightly increased the fraction of inactivated currents (by 15% ± 4%) and widened the range of the slow inactivation voltage dependence. Lamotrigine and rufinamide induced weak, but significant, shifts of I(Na) slow inactivation toward more depolarized potentials. The effects of lacosamide on Na(v) channel slow inactivation corroborate previous observations that lacosamide has a unique mode of action among AEDs that act on Na(v) channels.

Background Correction of prominent ears is a common plastic surgical procedure. We introduced a new non-invasive laser-assisted cartilage reshaping (LACR) technique as an alternative to invasive surgical otoplasty. Methods Since our first report in 2006, 32 LACR procedures in 17 patients have been performed at the Antoni De Gimbernat Foundation in collaboration with the French National Institute of Health and Medical Research (INSERM) U703. For 15 patients, the procedure was bilateral, for the remaining 2 patients LACR was performed only on one side. The treatment consisted of seven stacked pulses (3 ms, 2 Hz, 84 J/cm2 cumulative fluence) applied using a 4-mm spot hand piece. Early and late complications were defined and reviewed for the whole series. Satisfaction was assessed by the patients using a visual analogue scale from 0 (unsatisfied) to 10 (highly satisfied). The superior and middle cephaloauricular distances were prospectively evaluated. Results Except for two cases of dermatitis, there were no early complications and no late complications (like keloids) in the series. The mean superior and middle cephaloauricular distances were, respectively, 12.3 ± 1.9 and 13.7 ± 1.6 mm compared to 17.8 ± 3.1 mm (p

Since the initial work of Jacobson and Suarez in 1960, microsurgery has evolved greatly. In 2009, we reported our clinical experience with 1.9 µm diode laser-assisted vascular microanastomoses (LAMA) for free flap reconstruction. In this report, the ongoing study is now expanded to include 11 additional procedures which were analyzed prospectively with a focus on the duration of the LAMA technique.

Carpal tunnel syndrome is the most common entrapment neuropathy in the upper extremity. A rare case of carpal tunnel syndrome due to solitary osteochondroma arising from the metaphysis of the distal radius is presented. Preoperative diagnosis was suspected by physical examination and high-resolution sonography and confirmed by radiographs. Surgical treatment consisted of extended open carpal tunnel release and excision of the tumor. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound 42:557–559, 2014

A PS-b-PIP-b-PMMA copolymer has been melt-blended with homo-PMMA with a similar molecular weight as the PMMA block. For a 50:50 wt.-% mixture, the components form 3D bicontinuous lamellae. Upon annealing at 190 °C, a more regular network is observed, which consists of PMMA and 55 nm-thick bilayered lamellae of triblock copolymer, both being continuous. This co-continuity persists even when of the homo-PMMA is twice that of the PMMA block in the copolymer. For 30:70 and 20:80 wt.-% copolymer/homopolymer pair, the copolymer forms cylindrical and spherical phases, respectively. Blends have also been prepared by solvent casting. Large domains of copolymer interconnected by few lamellae are observed in the 50:50 blend that reorganize into a bicontinuous network upon annealing.

Venous ulcers are chronic wounds affecting up to 1% of adults in developed countries. Considering that noncontact normothermic therapy has been shown to modify the wound healing process, we conducted a prospective comparative clinical trial aimed at evaluating 980 nm diode laser in laser-assisted venous ulcer healing. Thirty-four Caucasian patients with venous leg ulcers were included in the study and separated into two homogenous groups based on age, sex ratio, size, and etiologies of the ulcers. In the laser group, 980 nm InGasAs diode laser (power 15 W, spot size 8 mm, time 3 seconds, fluence 90 J/cm 2 ) was applied weekly for 9 weeks to the ulcers in a homogenous standardized manner, resulting in a local temperature of 45-50 °C, which was controlled with a thermal infrared camera. Complete healing, reduction in size, and pain during and between each procedure were evaluated each time. Of the 18 patients in the laser group, three (16.7%) were completely healed during laser treatment. In the control group (16 patients), the healing was complete for four patients (25%). This difference was not significant (p=0.62). At the ninth follow-up visit, in the control group, the ulcers had decreased on an average to 94.3% of the original area of the ulcers. In the laser group, the decrease was to 74.2% of the original area of the ulcers. Again, this difference was not significant (p=0.60). The mean VAS score between each treatment was 2.7 (0.5-4.4) in the laser group compared with 3.8 (2.3-5.0) in the control group (0.13 < p < 0.86). During the treatment, the mean VAS score was 1.8 (0.2-3.8) in the laser group compared with 3.8 (2.1-6.0) in the control group (0.08 < p < 0.67). 980 nm diode laser-assisted venous ulcer healing was easy to perform and very well tolerated. However, there were no statistically significant differences in reduction of ulcer size between the two groups, suggesting that this particular laser regimen does not promote wound healing. Additional studies involving larger patient populations and an increased frequency of treatment should be performed to confirm our initial conclusions.

Background and Objectives Occurring in one-third of the population, nasal obstruction is the most common complaint in an average rhinologic practice. The etiology is usually a deviation of the nasal septum, although other conditions, such as turbinate hypertrophy, can also cause nasal obstruction. Our team has already demonstrated that laser assisted cartilage reshaping can be used effectively for the correction of ear protrusion. This study aims to evaluate laser assisted septal cartilage reshaping (LASCR) to treat septal deviation. Study Design Between March 2009 and September 2009, 12 patients (8 males, 4 females—mean age: 23 years) underwent LASCR for treatment of septal deviation. The mean NOSE score was 11.6. Preoperative examination included rhinomanometry and nasal endoscopy to exclude inferior turbinate or adenoid hypertrophy. Both sides of the septum were irradiated using a 1,540 nm laser connected to a 4 mm spot handpiece with integrated cooling (fluence: 50 J/cm2). Contact cooling made the treatment tolerable, but topical anesthesia was still required. Immediately after the procedure, an internal splint was inserted into the nostril and kept for 7 days. The NOSE score was calculated at 1 week, 1 month, and 3 months post-procedure and a rhinomanometry was carried out at 3 months. Results The entire procedure took an average of 20 minutes. For all procedures, there were no lesions of the septal mucosa. Three months post-op, mean NOSE score improved from 11.6 to 5.3. Rhinomanometry assesses an increase in airflow (+19%) and improvement to air inflow resistance (−16%), confirming a subjective improvement. In seven adults, the expected septal reshaping was achieved. In five adults, incomplete septum reshaping was observed. In three patients it was correlated to anatomical variations: a thick septum in two cases and a long septum in one case. In the remaining two patients, it was due to insufficient fluence. In these cases, insufficient local anesthesia did not allow us to finish the procedure and the patients received a fluence of 30 J/cm2 only. Those patients were re-treated at 3 months at 50 J/cm2 fluence and all achieved suitable reshaping. Conclusion LASCR is a safe and less morbid approach to surgical septoplasty. Since significant variability in the cartilaginous elements of the nose is the rule rather than the exception, some improvements in the technique are still required. Lasers Surg. Med. 42:693–698, 2010 © 2010 Wiley-Liss, Inc.

The injection of liquid in a hot fluidized bed is used in many industrial processes. The larger droplets are likely to engulf particles and create agglomerates that should be avoided when a fast vaporization is expected. A new model is proposed to estimate the chances of agglomeration based on a critical bed temperature below which agglomerates form. This critical temperature for safe operating conditions is based on heat transfer between the particles and the liquid and takes the porosity of the solid into account. The model could be applied to pure and multi-component mixtures and has been validated experimentally.

The self-assembly of organic molecules has attracted sub-stantialinterest asa bottom-upapproachto createnano-sizedobjects. Their properties depend strongly on the design,arrangement, and number of molecules in the aggregate. Forsupramolecular polymers, the monomers are entirely heldtogether by non-covalent interactions; these interactions aretypically weak, reversible, and highly sensitive to variablessuch as temperature, concentration, and solvent polarity.

This study was performed to review our 16-year experience in acute finger ischemia. A review of the literature was also performed. A retrospective chart review of 17 patients, 14 men and 3 women, was conducted. Etiologies were ulnar aneurysm in 11 cases, atrial fibrillation in five cases and thoracic outlet syndrome in one case. Upto the palmar superficial arch, embolus due to atrial fibrillation or thoracic outlet syndrome could be loosened by a Fogarty catheter. In cases of aneurysm of the ulnar artery, we performed each time an aneurysm resection followed by direct anastomose alone, while three patients had additional grafts: artery graft (epigastric artery) or reversed vein grafts (superficial forearm vein). Microsurgical dissection of the digital collateral arteries enabled us to perform a thrombectomy. The transversal arteriotomies were closed after the collateral arteries were washed. The immediate perfusion of digit after the reconstruction of the aneurysm was each time excellent. The disoccluded vessels, investigated by Allen testing and Doppler ultrasound, were all patents. Two patients suffered from a small ulcer of the small fingertip that disappeared after 2 weeks. One patient had a 30 degrees ischemic flexion contracture in the metacarpophalangeal joint and 25 degrees flexion contracture in the proximal interphalangeal joint of the third digit. With regards to long-term outcomes, no secondary amputations were necessary and there was no recurrence after a mean follow-up of 10.7 years. Diagnostic of acute digital ischemia is often neglected. An early recognition and an aggressive microsurgical treatment are necessary to ensure low morbidity.

Five fluorene-based co-oligomers have been prepared to study their self-assembly in a wide range of concentrations, from dilute solutions to the solid state. Subtle changes to the chemical structures, introduced to tune the emission colours over the entire visible range, induce strong differences in aggregation behaviour. Only two of the fluorescent co-oligomer derivatives self-assemble to form soluble fibrils from which fluorescent organogels emerge at higher concentrations. In contrast, the other compounds form precipitates. Mixed fluorescent co-oligomer systems exhibit partial energy transfer, which allows the creation of white-light-emitting gels. Finally, a mechanism for the hierarchical self-assembly of this class of materials is proposed based on experimental results and molecular modelling calculations. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.

The templated self-assembly of water-sol. pi-conjugated mols. bearing a diaminotriazine moiety H-bonding to a single-strand oligothymine template leads to defined structures. We study these assemblies with mol. modeling, CD spectroscopy, and scanning probe microscopy, to get a better understanding of the factors governing the supramol. organization and structural order. [on SciFinder (R)]

Thin films of TiO2 are deposited by magnetron sputtering on glass substrate and are irradiated by UV radiation using a KrF excimer laser (λ = 248 nm). The present works deals with the ablation regime. In order to characterize the structural transformations occurring in the process, the morphology of the films are studied as a function of the laser fluence (F), by means of profilometry and atomic force microscopy (AFM). As deposited films are measured to be amorphous. After one pulse, when the laser fluence, F, is varied, various regimes are observed. We show thanks to this process, it is possible to remove a layer in a predefined thickness by choosing F. More over, we observe a linear dependence of the ablated depth with F. It is shown that the morphology of the surfaces depends strongly of F, as evidenced from AFM images, roughness measurements and the fractal dimension. In order to interpret these results, temperature evaluations are performed. The ablation rate may not be explained by purely thermal effects. It is argued that electronic effects play a major role in excimer-laser induced structural transformations of TiO2 thin films. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The Plumularioidea (Cnidaria, Hydrozoa, Leptothecata) are the most species rich superfamily of the class Hydrozoa. They display a complex and diversified colonial organisation and their life cycle comprises either a reduced free-living, pelagic generation (medusoid), alternating with the benthic colonial form or in most species, no pelagic generation. In order to understand the evolution of colonial and life cycle characters among Plumularioidea, we have reconstructed their phylogeny. Partial mitochondrial 16S rRNA sequences and 64 morphological characters were analysed separately and in combination. The morphological data included not only characters of the individual polyps and medusae, but also characters describing the organisation of colonies, for which we propose general principles applying to character coding in modular organisms. The phylogenetic analyses supported the monophyly of Plumularioidea and of the four plumularioid families (Aglaopheniidae, Halopterididae, Kirchenpaueriidae and Plumulariidae). Most genera were paraphyletic or polyphyletic. This study highlights multiple morphological simplifications of the colonial organisation during the evolution of Plumularioidea and the convergence of the defensive polyps — the dactylozooids — of Plumularioidea with those of others Leptothecata (Hydrodendron) or Anthoathecata (Hydractinia). Concerning the evolution of the life cycle, the phylogeny supports a provocative scenario, where the medusa was lost in an ancestor of the Plumularioidea, and then re-acquired four times independently within this group, in the form of simple medusoids.

A series of conjugated copolymers containing fluorene or indenofluorene units alternating with oligothiophene segments, with potential interest for use as the active layer in field-effect transistors, is investigated. Atomic force microscopy analysis of the morphology of thin deposits shows either the formation of fibrillar structures, which are the signature of long-range π stacking, or the presence of untextured aggregates, resulting from disordered assembly. These morphologies are interpreted in terms of the supramolecular organization of the conjugated chains. Molecular modeling simulations indicate that the commensurability between the lengths of the monomer units and the presence of alkyl side groups are the two key structural factors governing the chain organization into highly ordered assemblies. The most favorable structures are those combining fluorene (indenofluorene) units with unsubstituted bithiophene (terthiophene) segments.

In this paper, we describe the synthesis and characterization of poly(9,9′-dioctylfluorene)–poly(ethylene oxide) (PF-PEO) block copolymers with different block ratio and molecular architectures (diblock or triblock copolymers). Tapping-mode atomic force microscopy is used to investigate the relationship between the molecular structure and the microscopic morphology of thin deposits. Copolymers with a low average volume ratio of PEO (fEO from 0.1 to 0.3) exhibit a well-defined organization into nanoribbons. A model of chain packing is proposed; these structures arise from the interplay of π–π interactions between conjugated PF segments and the interactions of PEO with the mica substrate surface. For copolymers with higher average volume ratio of PEO (fEO > 0.4), the organized structures disappear and lead to untextured aggregates, probably because long-range, regular π–π stacking of the segments can no longer take place. We also observe that the nature of the solvent from which deposits are grown and the substrate polarity have a strong impact on the microscopic morphology.

The emission properties of polyindenofluorenes with various proportions of straight- and branched-chain alkyl substituents have been compared. The polymer with straight octyl substituents shows green emission due to formation of aggregates, while the polymer with branched 2-ethylhexyl substituents shows blue emission. Studies of the film morphology show the presence of ordered structures due to π-stacking of the polymer chains for the octyl-substituted polymer, whereas the polymer with branched side-chains shows no such order. Copolymers show intermediate behavior. A clear correlation is established between the degree of straight-chain alkyl substitution, the formation of ordered structures in the films, and the amount of long wavelength emission in the solid-state spectra.

The recent emergence of hyperbranched polymers has opened the door for the design of a large variety of novel, well-controlled chain architectures. For instance, «comb-like» and dendritic-like polymers can be obtained from hyperbranched poly(chloroethyl vinyl ether)-g-polystyrene (PCEVE-g-PS) copolymers, with excellent control over the dimensions of the polystyrene lateral branches and the PCEVE backbone. In this work, the nanometer scale organization of these materials is studied by means of Tapping Mode Atomic Force Microscopy. We focus on the influence of the intrinsic molecular architecture of the hyperbranched PCEVE-g-PS on the organization of the material. In the case of thin deposits, we observe a layer-by-layer organization. On the free surface, it is possible to image single polymer molecules and to analyze their size in terms of polymer molecular weight. In most cases, the molecules are found to adopt an extended conformation and to form lamellar arrangements. We observe that the degree of lateral ordering of these molecules strongly depends on their intrinsic architecture.

Atomic Force Microscopy (AFM) is used to study the phase separation process occurring in block copolymers in the solid state. Measuring simultaneously the amplitude and the phase of the oscillating cantilever in tapping-mode operation provides the surface topography along with the cartography of microdomains with different mechanical properties. This in turn allows to characterize the organization of the various components at the surface in terms of well-defined morphologies (e.g., spheres, cylinders, or lamellae). Here this approach is applied to a series of symmetric triblock copolymers made of a central elastomeric segment (polyalkylacrylate) surrounded by two thermoplastic sequences (polymethylmethacrylate). The occurrence of microphase separation in these materials and the resulting microscopic morphology are essential factors for determining their potential applications as a new class of thermoplastic elastomers. This paper describes how the surface morphology can be controlled by the molecular structure of the copolymers (volume ratio between the sequences, molecular weight, length of the alkyl side group) and by the experimental conditions used for the preparation of the films. The molecular structure of the chains is fully determined by the synthesis of the copolymers via living anionic polymerization while the parameters that can be modified when preparing the samples are the nature of the solvent and the thermal annealing of the films. Finally, we report on a systematic comparison between images and approach-retract curve data. We show that this experimental comparison allows the origin of the contrast that produces the image to be straightforwardly evaluated. The method provides an unambiguous quantitative measurement of the contribution of the local mechanical response to the image. We show that most of the contrast in the height and phase images is due to variations in local mechanical properties and not in topography.

The phase morphology and rheological properties of a series of poly(methyl methacrylate)-block-poly(isooctyl acrylate)-block-poly(methyl methacrylate) triblock copolymers (MIM) have been studied. These copolymers have well-defined molecular structures, with a molecular weight (MW) of poly(methyl methacrylate) (PMMA) in the range of 3 500–50 000 and MW of poly(isooctyl acrylate) (PIOA) ranging from 100 000 to 140 000. Atomic force microscopy with phase detection imaging has shown a two-phase morphology for all the MIM copolymers. The typical spherical, cylindrical, and lamellar phase morphologies have been observed depending on the copolymer composition. MIM consisting of very short PMMA end blocks (MW 3 500–5 000) behave as thermoplastic elastomers (TPEs), with however an upper-service temperature higher than the traditional polystyrene-block-polyisoprene-block-polystyrene TPEs (Kraton D1107). A higher processing temperature is also noted, consistent with the higher viscosity of PMMA compared to PS.

The microscopic organization in thin films of block copolymers containing either polyparaphenylene, or polyphenyleneethynylene rigid segments covalently bound to a flexible polydimethylsiloxane or polystyrene sequence was investigated. Atomic force microscopy and theoretical modeling based on molecular mechanics/molecular dynamics calculations were combined. The typical morphology obtained revealed the presence of bright elongated structures.