Controlled immobilization of a palladium complex/laccase hybrid into a macrocellular siliceous host

This study investigates the site-directed immobilization of a hybrid catalyst bearing a biquinoline-based-Pd(II) complex (1) and a robust laccase within cavities of a silica foam to favor veratryl alcohol oxidation. We performed the grafting of 1 at a unique surface located lysine of two laccase variants, either at closed (1⊂UNIK157) or opposite position (1⊂UNIK71) of the enzyme oxidation site. After immobilization into the cavities of silica monoliths bearing hierarchical porosity, we show that catalytic activity is dependent on the orientation and loading of each hybrid, 1⊂UNIK157 being twice more active than 1⊂UNIK71 (203 TON vs 100 TON) when operating under continuous flow. These systems can be reused 5 times, with an operational activity remaining as high as 40 %. We show that the synergy between 1 and laccase can be tuned within the foam. This work is a proof of concept for controlling the organization of a heterogeneous hybrid catalyst using a Pd/laccase/silica foam.

Computational Insights of Selective Intramolecular O-atom Transfer Mediated by Bioinspired Copper Complexes

The stereoselective copper-mediated hydroxylation of intramolecular C-H bonds from tridentate ligands is reinvestigated using DFT calculations. The computational study aims at deciphering the mechanism of C-H hydroxylation obtained after reaction of Cu(I) precursors with dioxygen, using ligands bearing either activated (L¹ ) or non-activated (L² ) C-H bonds. Configurational analysis allows rationalization of the experimentally observed regio- and stereoselectivity. The computed mechanism involves the formation of a side-on peroxide species (P) in equilibrium with the key intermediate bis-(μ-oxo) isomer (O) responsible for the C-H activation step. The P/O equilibrium yields the same activation barrier for the two complexes. However, the main difference between the two model complexes is observed during the C-H activation step, where the complex bearing the non-activated C-H bonds yields a higher energy barrier, accounting for the experimental lack of reactivity of this complex under those conditions.

Modulation of laccase catalysed oxidations at the surface of magnetic nanoparticles

We explored the coupling of laccases to magnetic nanoparticles (MNPs) with different surface chemical coating. Two laccase variants offering two opposite and precise orientations of the substrate oxidation site were immobilised onto core-shell MNPs presenting either aliphatic aldehyde, aromatic aldehyde or azide functional groups at the particles surface. Oxidation capabilities of the six-resulting laccase-MNP hybrids were compared on ABTS and coniferyl alcohol. Herein, we show that the original interfaces created differ substantially in their reactivities with an amplitude from 1 to > 4 folds depending on the nature of the substrate. Taking enzyme orientation into account in the design of surface modification represents a way to introduce selectivity in laccase catalysed reactions.

Hydrogen evolution reaction mediated by an all-sulfur trinuclear nickel complex

A trinuclear nickel complex with S-based ligands is reported as a bio-inspired model of the [NiFe] hydrogenases' active site. DFT calculations indicate that thiolate and thioether functions are involved as proton relays in the H₂ evolution mechanism.

The role of methylation in the copper(ii) coordination properties of a His-containing decapeptide

N-Methylation: a simple strategy to stabilize copper species lacking amidate coordination at neutral pH value.

Note: Efficient diode laser line narrowing using dual, feed-forward + feed-back laser frequency control

We have achieved distributed feedback laser diode line narrowing by simultaneously acting on the diode current via a feed-back loop and on an external electrooptic phase modulator in feed-forward actuator. This configuration turns out to be very efficient in reaching large bandwidth in the phase correction: up to 15 MHz with commercial laser control units. About 98% of the laser power undergoes narrowing. The full width at half maximum of the narrowed optical spectrum is of less than 4 kHz. This configuration appears to be very convenient as the delay in the feed-forward control electronics is easily compensated for by a 20 m optical fiber roll.

[Diogenes syndrome and Hoarding disorder: Same or different?]

INTRODUCTION

In 2013, the American Psychiatric Association published the DSM-5. In this new version, new diagnoses were proposed including the Hoarding disorder. In the French semeiology, the Diogenes syndrome is described, among other symptoms, by a pathological tendency to accumulate objects called syllogomania which is very close to hoarding. This paper explores the similarities and differences between the two syndromes.

DESCRIPTION

The Diogenes syndrome was first described in 1966 but was officially named for the ancient Greek philosopher in 1975 by Clark. Its frequency is around five for 100,000 persons. Many aetiologies have been known to be associated with the Diogenes syndrome: schizophrenia, dementia - especially frontotemporal type, anxiety disorders, mood disorders, and substance abuse - especially alcohol abuse. The diagnostic requires one major criterion, the inability to ask for medical or social help, and one of three minor criteria: a pathological relationship to the body, which leads to somatic illness; a pathological relationship to the society, which leads to a progressive exclusion from it; and finally, a pathological link with objects. This last criterion is very interesting because it is closely related to the Hoarding syndrome: indeed, patients with syllogamania, as also named, have a tendency to hoard every object they find. At the end, their homes are full of useless objects, and some living places can be unusable because they are cluttered and congested. This last point is similar to the definition given in the DSM-5 for the Hoarding disorder which describes a persistent difficulty parting with possessions; distress associated with discarding possessions; and accumulations that congest and clutter active living areas. The Hoarding disorder was first part of the Obsessive and compulsive disorders, but it has progressively appeared that it could be individualized with its own prevalence of 2.3% to 14% lifetime. Genetical studies have shown that at least 50% of patients suffering from excessive hoarding had a relative with a dimension of hoarding. Finally, Mattaix-Cols et al. decided to create a new syndrome in the DSM-5, and the Hoarding disorder was born.

DISCUSSION

The discussion begins with relationships between the Hoarding disorder and the Diogenes syndrome. A patient with hoarding, and a poor insight, could be very isolated, and could persist in a lack of calling for help, because of not being aware of his pathology. Thus, it could be diagnosed as a Hoarding syndrome with a poor insight, or as a Diogenes syndrome, with the first major criterion (lack of calling for help) and one of the three minor criteria, the syllogomania, or hoarding. Moreover, some authors have described old people living for many years with a tendency to hoard. Progressively, some of them had a congested and cluttered home, and a few were living in squalor, a description very close to the Diogenes syndrome. Finally, we discuss the comorbidity of Hoarding disorder and Diogenes syndrome. In particular, the first one is associated with Attention deficit and hyperactivity disorders; and some authors also described the links between ADHD, bipolar disorder and frontotemporal dementia which is one of the aetiologies of the Diogenes syndrome. A psychodynamic model in which ADHD, Hoarding disorder and Diogenes syndrome are linked can be imagined, and the last one could be an overlooked evolution of the two first syndromes.

CONCLUSION

In conclusion, we can imagine a dimensional model, based on two dimensions: hoarding and squalor. Hoarding disorder is the major expression of the first dimension, and Diogenes syndrome the major expression of the second. Both of them could be a different expression of one central aetiology. More studies are needed to complete this vision.

Supramolecular complexes involving non-symmetric viologen cations and hexacyanoferrate(ii) anions. A spectroscopic, crystallographic and computational study

We have investigated spectrally, crystallographically as well as computationally charge transfer complexes involving synthesized N-aryl-N′-methyl non-symmetric viologen cations and hexacyanoferrate(ii) anions.

Longwave infrared, single-frequency, tunable, pulsed optical parametric oscillator based on orientation-patterned GaAs for gas sensing

We demonstrate a nanosecond single-frequency nested cavity optical parametric oscillator (NesCOPO) based on orientation-patterned GaAs (OP-GaAs). Its low threshold energy of 10 μJ enables to pump it with a pulsed single-frequency Tm:YAP microlaser. Stable single-longitudinal-mode emission is obtained owing to Vernier spectral filtering provided by the dual-cavity doubly-resonant NesCOPO scheme. Crystal temperature tuning covers the 10.3-10.9 μm range with a quasi-phase-matching period of 72.6 μm. A first step toward the implementation of this device in a differential absorption lidar is demonstrated by carrying out short-range standoff detection of ammonia vapor around 10.4 μm. Owing to the single-frequency emission, interferences due to absorption by atmospheric water vapor can be discriminated from the analyte signal.

PHARAO laser source flight model: design and performances

In this paper, we describe the design and the main performances of the PHARAO laser source flight model. PHARAO is a laser cooled cesium clock specially designed for operation in space and the laser source is one of the main sub-systems. The flight model presented in this work is the first remote-controlled laser system designed for spaceborne cold atom manipulation. The main challenges arise from mechanical compatibility with space constraints, which impose a high level of compactness, a low electric power consumption, a wide range of operating temperature, and a vacuum environment. We describe the main functions of the laser source and give an overview of the main technologies developed for this instrument. We present some results of the qualification process. The characteristics of the laser source flight model, and their impact on the clock performances, have been verified in operational conditions.

Laccases as palladium oxidases

The first example of a coupled catalytic system involving an enzyme and a palladium(ii) catalyst competent for the aerobic oxidation of alcohol in mild conditions is described. In the absence of dioxygen, the fungal laccase LAC3 is reduced by a palladium(0) species as evidenced by the UV/VIS and ESR spectra of the enzyme. During the oxidation of veratryl alcohol performed in water, at room temperature and atmospheric pressure, LAC3 regenerates the palladium catalyst, is reduced and catalyzes the four-electron reduction of dioxygen into water with no loss of enzyme activity. The association of a laccase with a water-soluble palladium complex results in a 7-fold increase in the catalytic efficiency of the complex. This is the first step in the design of a family of renewable palladium catalysts for aerobic oxidation.

Comparison of heme and nonheme iron-based 1-aminocyclopropane-1-carboxylic acid oxidase mimics: kinetic, mechanistic and computational studies

Kinetic, mechanistic and computational studies of the H₂O₂oxidation of 1-aminocyclopropane-1-carboxylic acid to ethylene by heme- and nonheme-type iron complexes are described as biomimics of 1-aminocyclopropane-1-carboxylic acid oxidase.

Thermally driven dual-frequency Q-switching of Nd:YGd2Sc2Al2GaO12 ceramic laser

Multi-wavelength operation of Q-switched Nd-doped YGd(2)Sc(2)Al(2)GaO(12) garnet ceramic lasers has been investigated. Dual-wavelength emission around ~1.06 µm has been demonstrated both in the actively and passively Q-switched configurations. The ratio of output energy between the two laser wavelengths was driven by the temperature elevation caused by pumping. Passively Q-switched operation yields dual-frequency emission of two unsynchronized laser pulses carried by distinct transverse modes whereas active Q-switched configuration offers the possibility of synchronizing emission at the two wavelengths.

Germanium-On-Insulator (GeOI) structure realized by the Smart Cut™ technology

First results on formation of thin film GeOI structures by the Smart Cut™ technology are presented in this paper. Thin single crystal layers of Ge have been successfully transferred, via oxide bonding layer, onto standard Si substrates with diameters ranging from 100 to 200 mm. Compared to SOI manufacturing, the development of GeOI requires adaptation to the available germanium material, since the starting material can be either bulk Ge or an epitaxial layer. Some results will be presented for GeOI formation according to the different technological options. Germanium splitting kinetics will be discussed and compared to already published results. To show good quality of the GeOI structures, detailed characterization has been done by TEM cross sections for defect densities, interfaces abruptness and layers homogeneities evaluation. AFM was used for surface roughness measurements. These results help define procedures that are required to achieve large diameter high quality GeOI structures.

Evidence for a slightly deleterious effect of intron polymorphisms at the EF1alpha gene in the deep-sea hydrothermal vent bivalve Bathymodiolus

A multilocus analysis was initiated in order to infer the general effect of demography and the indirect effect of positive selection on some chromosome segments in Bathymodiolus. Mussels of the genus Bathymodiolus inhabit the very hostile, fragmented and variable environment of deep-sea hydrothermal vents which is thought to cause recurrent population bottlenecks via extinction/colonisation processes and adaptation to new environmental conditions. In the course of this work we discovered that the assumption of neutrality of non-coding polymorphisms usually made in genome scan experiments was likely to be violated at one of the loci we analysed. The direct effect of slight purifying selection on non-coding polymorphisms shares many resemblances with the indirect effect of positive selection through genetic hitchhiking. Combining polymorphism with divergence data for several closely related species allowed us to obtain different expectations for the direct effect of negative selection and the indirect effect of positive selection. We observed a strong excess of rare non-coding polymorphisms at the second intron of the EF1alpha gene in the two species Bathymodiolus azoricus and Bathymodiolus thermophilus, while two other loci, the mitochondrial COI gene and an intron of the Lysozyme gene, did not exhibit such a deviation. In addition, the divergence rate of the EF1alpha intron was estimated to be unexpectedly low when calibrated using the closure of the Panama Isthmus that interrupted gene flow between the two species. The polymorphism to divergence ratio was similar to the one observed for the other two loci, in accordance to the hypothesis of purifying selection. We conclude that slight purifying selection is likely to act on polymorphic intronic mutations of the EF1alpha second intron and discuss the possible relationship with the specific biology of Bathymodiolus mussels.

Isolation and characterisation of 8-hydroxy-3Z,5Z-tetradecadienoic acid, a putative intermediate in Pichia guilliermondii gamma-decalactone biosynthesis from ricinoleic acid

During a screening procedure for the discovery of a strong gamma-decalactone producer from ricinoleic acid, we observed that the yeast Pichia guilliermondii accumulated transiently 8-hydroxy-3Z,5Z-tetradecadienoic acid 1 during gamma-decalactone biosynthesis in the stationary phase of growth. The structural elucidation of 1 was based on nuclear magnetic resonance, infrared, ultraviolet and gas chromatography-mass spectrometry experiments. The occurrence of 1 is discussed in relation with previously proposed gamma-decalactone biosynthetic pathways.

A new tannase substrate for spectrophotometric assay

A new tannase substrate, protocatechuic acid p-nitrophenyl ester, 5, was synthesized using modern synthetic methods. The synthesis was designed to be performed by non-specialized chemists. It only involves four steps, three of which are protection-deprotection, and uses standard methods of separation and purification, such as recrystallization and column chromatography over silica. Under tannase action, protocatechuic acid p-nitrophenyl ester, 5, releases p-nitrophenol, which is easily measured spectrophotometrically either at 350 nm for pH values<6 or at 400 nm for pH values of 6-7 (yellow). The pH-response and the catalytic parameters of a crude Penicillium sp. tannase preparation were determined using 5 as substrate, thus showing the usefulness of this substrate in determining tannase activity.

Estimating the centre of gravity of the body on the basis of the centre of pressure in standing posture

This study proposes to estimate the horizontal positions of the body's centre of gravity (CoG) in a standing posture, on the basis of the horizontal positions of the centre of pressure (CoP). The latter were measured with a force plate, and using a low-pass filter defined by a mathematical relationship of the relative magnitude of the CoG with respect to the magnitude of the CoP, as a function of the frequency oscillations (Brenière, 1996, Journal of Motor Behaviour 28, 291-298). This relationship was computed from the angular momentum equation applied to the whole body with respect to the CoG using the inverse dynamics approach and force plate recordings, and considering the CoP and CoG oscillations as simple periodic functions. Five subjects were asked to perform voluntary oscillations along medio-lateral and antero-posterior axes, keeping their bodies straight, and without moving their feet. The CoG accelerations measured by the force plate were compared with the CoG accelerations derived from the estimated CoG positions. The average root-mean-square difference between these accelerations was very small, confirming the accuracy of this method. This simplified way to calculate the CoG positions, rarely measured in standing, allows a comparative assessment of motion performance. This method could also be applied to other kinds of movement such as walking.

Structure and function of the photoreceptor stentorins in Stentor coeruleus. I. Partial characterization of the photoreceptor organelle and stentorins

The unicellular ciliary protozoan, Stentor coeruleus, exhibits photophobic and phototactic responses to visible light stimuli. The pigment granule contains the photoreceptor chromoproteins (stentorins). Stentorin localized in the pigment granules of the cell serves as the primary photoreceptor for the photophobic and phototactic responses in this organism. An initial characterization of the pigment granules has been described in terms of size, absorbance spectra and ATPase activity. Two forms of the stentorin pigments have been isolated from the pigment granules. Stentorin I has an apparent molecular weight of 68,600 and 52,000 by SDS-PAGE (at 10 and 13% gel, respectively) or 102,000 by steric exclusion HPLC, whereas stentorin II is a larger molecular assembly probably composed of several proteins (mol. wt. greater than 500,000). Stentorin I is composed of at least two heterologous subunits corresponding to apparent mol. wts. of 46,000 (fluorescent, Coomassie blue negative) and 52,000 (fluorescent, Coomassie blue positive) on SDS-PAGE (13% gel). However, these values were found to be strongly dependent on the degree of crosslinking in the acrylamide gel. Stentorin II appears to be the primary photoreceptor whose absorption and fluorescence properties are consistent with the action spectra for the photoresponses of the ciliate to visible light.

Retroperitoneal lymph node aspiration biopsy in staging of pelvic cancer: a cytological study of 228 consecutive cases

Knowledge of the status of the pelvic lymph nodes is important for accurate staging and adequate treatment of patients with genitourinary tract cancer (bladder and prostatic carcinoma, testicular tumors, and uterine carcinoma). A total of 228 consecutive patients underwent preoperative evaluation of the lymph node status by lymphangiography combined with fine-needle aspiration biopsy. A lymphadenectomy was performed in 94 patients. The overall diagnostic accuracy was 93%. There were 5% false-negative results and no false-positive diagnoses. Fine-needle aspiration biopsy is an inexpensive method with which to detect the presence of metastatic lymph nodes visualized by bipedal lymphangiography. It is also a safe and well-tolerated method, with a low morbidity and no mortality. The various cytological features are described as are some possible pitfalls.