Development of a low-cost silica-titania optical platform for integrated photonics applications.

This paper investigates a highly attractive platform for an optical waveguide system based on silica-titania material. The paper is organized into two parts. In the first part, an experimental study on the development of an optical waveguide system is conducted via the sol-gel dip-coating method, and the optical characterization of the waveguide system is performed at a visible wavelength. This system is capable of operating from visible to near-IR wavelength ranges. The experimental results prove the dominance of this waveguide platform due to its low-cost, low loss, and easy to develop integrated optics systems. The numerical analysis of a one-dimensional Photonic crystal waveguide optical filter based on the silica-titania platform is considered in the second part of the paper by utilizing the 2D-finite element method (2D-FEM). A Fabry-Perot structure is also analyzed for refractive index sensing applications. We believe that the results presented in this work will be valuable in the realization of low-cost photonic integrated circuits based on the silica-titania platform.

Plasmonic sensor based on metal-insulator-metal waveguide square ring cavity filled with functional material for the detection of CO2 gas.

In this work, a straightforward and highly sensitive design of a CO2 gas sensor is numerically investigated using the finite element method. The sensor is based on a plasmonic metal-insulator-metal (MIM) waveguide side coupled to a square ring cavity filled with polyhexamethylene biguanide (PHMB) functional material. The refractive index of the functional material changes when exposed to the CO2 and that change is linearly proportional to the concentration of the gas. The sensors based on surface plasmon polariton (SPP) waves are highly sensitive due to the strong interaction of the electromagnetic wave with the matter. By utilizing PHMB polymer in the MIM waveguide plasmonic sensor provides a platform that offers the highest sensitivity of 135.95 pm/ppm which cannot be obtained via optical sensors based on silicon photonics. The sensitivity reported in this work is ∼7 times higher than reported in the previous works. Therefore, we believe that the results presented in this paper are exceedingly beneficial for the realization of the sensors for the detection of toxic gases by employing different functional materials.

Cytokinins résumé: their signaling and role in programmed cell death in plants.

Cytokinins (CKs) are a large group of plant hormones which play a crucial role in many physiological processes in plants. One of the interesting functions of CKs is the control of programmed cell death (PCD). It seems that all CKs-dependent phenomena including PCD are accompanied by special multi-step phosphorelay signaling pathway. This pathway consists of three elements: histidine kinase receptors (HKs), histidine phosphotransfer proteins (HPs) and response regulators (RRs). This review shows the résumé of the latest knowledge about CKs signaling pathways in many physiological processes in plants with special attention paid to PCD process.

A packaged optical slot-waveguide ring resonator sensor array for multiplex label-free assays in labs-on-chips.

We present the design, fabrication, and characterisation of an array of optical slot-waveguide ring resonator sensors, integrated with microfluidic sample handling in a compact cartridge, for multiplexed real-time label-free biosensing. Multiplexing not only enables high throughput, but also provides reference channels for drift compensation and control experiments. Our use of alignment tolerant surface gratings to couple light into the optical chip enables quick replacement of cartridges in the read-out instrument. Furthermore, our novel use of a dual surface-energy adhesive film to bond a hard plastic shell directly to the PDMS microfluidic network allows for fast and leak-tight assembly of compact cartridges with tightly spaced fluidic interconnects. The high sensitivity of the slot-waveguide resonators, combined with on-chip referencing and physical modelling, yields a volume refractive index detection limit of 5 x 10(-6) refractive index units (RIUs) and a surface mass density detection limit of 0.9 pg mm(-2), to our knowledge the best reported values for integrated planar ring resonators.

Novel and recurrent variants of ATP2C1 identified in patients with Hailey-Hailey disease.

Hailey-Hailey disease (HHD) is a rare, late-onset autosomal dominant genodermatosis characterized by blisters, vesicular lesions, crusted erosions, and erythematous scaly plaques predominantly in intertriginous regions. HHD is caused by ATP2C1 mutations. About 180 distinct mutations have been identified so far; however, data of only few cases from Central Europe are available. The aim was to analyze the ATP2C1 gene in a cohort of Polish HHD patients. A group of 18 patients was enrolled in the study based on specific clinical symptoms. Mutations were detected using Sanger or next generation sequencing. In silico analysis was performed by prediction algorisms and dynamic structural modeling. In two cases, mRNA analysis was performed to confirm aberrant splicing. We detected 13 different mutations, including 8 novel, 2 recurrent (p.Gly850Ter and c.325-3 T > G), and 6 sporadic (c.423-1G > T, c.899 + 1G > A, p.Leu539Pro, p.Thr808TyrfsTer16, p.Gln855Arg and a complex allele: c.[1610C > G;1741 + 3A > G]). In silico analysis shows that all novel missense variants are pathogenic or likely pathogenic. We confirmed pathogenic status for two novel variants c.325-3 T > G and c.[1610C > G;1741 + 3A > G] by mRNA analysis. Our results broaden the knowledge about genetic heterogeneity in Central European patients with ATP2C1 mutations and also give further evidence that careful and multifactorial evaluation of variant pathogenicity status is essential.

Heterogeneous integration of electrically driven microdisk based laser sources for optical interconnects and photonic ICs.

A new approach for an electrically driven microlaser based on a microdisk transferred onto Silicon is proposed. The structure is based on a quaternary InGaAsP p-i-n junction including three InAsP quantum wells, on a thin membrane transferred onto silicon by molecular bonding. A p++/n++ tunnel junction is used as the p-type contact. The technological procedure is described and first experimental results show a laser emission in pulsed regime at room temperature, with a threshold current near 1.5 mA.

Novel sporadic and recurrent mutations in KRT5 and KRT14 genes in Polish epidermolysis bullosa simplex patients: further insights into epidemiology and genotype-phenotype correlation.

Epidermolysis bullosa simplex (EBS) is a hereditary genodermatosis characterised by trauma-induced intraepidermal blistering of the skin. EBS is mostly caused by mutations in the KRT5 and KRT14 genes. Disease severity partially depends on the affected keratin type and may be modulated by mutation type and location. The aim of our study was to identify the molecular defects in KRT5 and KRT14 in a cohort of 46 Polish and one Belarusian probands with clinical suspicion of EBS and to determine the genotype-phenotype correlation. The group of 47 patients with clinical recognition of EBS was enrolled in the study. We analysed all coding exons of KRT5 and KRT14 using Sanger sequencing. The pathogenic status of novel variants was evaluated using bioinformatical tools, control group analysis (DNA from 100 healthy population-matched subjects) and probands' parents testing. We identified mutations in 80 % of patients and found 29 different mutations, 11 of which were novel and six were found in more than one family. All novel mutations were ascertained as pathogenic. In the majority of cases, the most severe genotype was associated with mutations in highly conserved regions. In some cases, different inheritance mode and clinical significance, than previously reported by others, was observed. We report 11 novel variants and show novel genotype-phenotype correlations. Our data give further insight into the natural history of EBS molecular pathology, epidemiology and mutation origin.

Reactive oxygen and nitrogen (ROS and RNS) species generation and cell death in tomato suspension cultures--Botrytis cinerea interaction.

This article reports events connected to cell survival and Botrytis cinerea infection development in cell suspension cultures of two tomato cultivars which show different levels of susceptibility to the pathogen: cv. Corindo (more susceptible) and cv. Perkoz (less susceptible). In parallel changes in reactive oxygen (ROS) and nitrogen (RNS) species generation and in S-nitrosoglutathione reductase (GSNOR) activity were studied. In vivo staining methods with acridine orange (AO) and ethidium bromide (EB) as well as fluorescent microscopy were used to assess tomato and B. cinerea cells death. The biochemical studies of ROS and RNS concentrations in plant cell extract were complemented by in vivo ROS and nitric oxide (NO) imaging using nitro blue tetrazolium (NBT), diaminobenzidine (DAB) and diaminofluorescein diacetate (DAF-DA) staining methods, and confocal microscope technique. B. cinerea infection proceeded slower in Perkoz cell cultures. It was evidenced by measuring the pathogen conidia germination and germination tube development in which nuclei revealing cell death dominated. Two different types of tomato cell death were observed: cells with necrotic nuclei dominated in Corindo whereas in Perkoz cells with characteristic of vacuolar death type prevailed. In Perkoz cells, constitutive levels of NO and S-nitrosothiols (SNO) were significantly higher and hydrogen peroxide (H2O2) and superoxide anion (O2(-)) concentrations were slightly higher as compared with Corindo cells. Moreover, increases in these molecule concentrations as a result of B. cinerea inoculation were observed in both, Perkoz and Corindo cell cultures. The enzymatic GSNOR activity seems to be an important player in controlling the SNO level in tomato cells. Involvements of the studied compounds in molecular mechanisms of tomato resistance to B. cinerea are discussed in the paper.

Biliary tract excretion of ofloxacin in man.

This study examined the biliary tract excretion of ofloxacin in 6 post-cholecystectomy patients with a T-tube inserted into the common duct (group A) and 6 patients during cholecystectomy (group B). The patients were given 7 oral doses of ofloxacin 200mg with a 12-hour interval between each dose. Blood and common duct bile samples were collected in group A at various time intervals after the first and the seventh dose. Blood, gallbladder wall, and gallbladder and common duct bile were collected in group B during operation, 6 hours after the seventh dose. Assays were performed by use of high performance liquid chromatography (HPLC). In group A, mean serum Cmax and half-life were 2.6 mg/L and 7.6 hours after the first dose, and 5.3 mg/L and 8 hours after the seventh dose, respectively. Mean common duct bile Cmax and half-life were 6.5 mg/L and 7.5 hours after the first dose, and 12.0 mg/L and 14 hours after the seventh dose, respectively. In group B, mean concentrations (mg/L) were 2.6 in blood, 5.3 in gallbladder wall, 24.6 in gallbladder bile and 10.1 in common duct bile, 6 hours after the seventh dose. These data suggest that ofloxacin may be suitable for the treatment of biliary tract infections.

Sulbactam: secondary mechanisms of action.

Light and scanning electron microscopy showed that 0.25, 0.5 and 1 times the minimum inhibitory concentrations (MICs) of sulbactam (SULB) caused filament formation in different species of Enterobacteriaceae, while 2 and 4 times the MICs caused spheroplast formation and subsequent lysis. By using a competitive assay with 125I-penicillin X, SULB showed a primary affinity for the PBP 1a and PBP3 of Escherichia coli, as well as for the PBP1a of Proteus mirabilis. The bactericidal interaction of human polymorphonuclear leukocytes (PMN) and SULB against E. coli K-1 resistant to the bactericidal activity of human serum was studied in vitro; however, SULB concentrations showed variations in the medium according to human kinetic data. Under these conditions, bacterial growth occurred in Hanks balanced salt solution containing SULB, PMN, or SULB-PMN in combination. In addition, bactericidal activity was observed in serum, with a killing rate of 90% for PMN or SULB, and 95% for SULB-PMN in combination. The postantibiotic enhancement of PMN bactericidal function was assessed against E. coli K1 pretreated with 0.5 the MIC of SULB (32 micrograms/ml) for 0.5 hr. The 90% bacterial killing rate of PMN occurred by 1.5 hr for pretreated bacteria and by 2.5 hr for untreated bacteria. Furthermore, the luminol-enhanced chemiluminescence (CL) assay using an E. coli stimulus showed that SULB does not modify PMN activity.

The ocular penetration of oral sparfloxacin in humans.

The penetration of sparfloxacin into the aqueous humor after oral administration was studied in 28 patients undergoing cataract surgery. Each patient received a single, oral dose of 400 mg of sparfloxacin. In eight other patients scheduled to undergo vitreal surgery, multiple daily oral doses were administered for a total amount of 1,000 mg. The aqueous levels were (mean +/- SEM) 0.127 +/- 0.036 microgram/ml to 0.404 +/- 0.159 microgram/ml from two to 24 hours after ingestion. In the vitreous, the mean drug level was 0.840 microgram/ml (range, 0.480 to 2.060 microgram/ml), from 4.3 to 8.0 hours after the most recent oral dose. Blood samples obtained at the same time as vitreous and aqueous taps were assayed by high-performance liquid chromatography. These data demonstrate that therapeutic levels of sparfloxacin may be achieved in noninflamed, noninfected eyes undergoing cataract or vitreous surgery.

ANTHERIDIAL CHROMATIN CONDENSATION FACTOR FROM MALE SEX ORGANS OF CHARA TOMENTOSA.

Incubation of roots (Melandrium noctiflorum) in crude extracts obtained from maturing male sex organs of Chara tomentosa results in supercondensation of mitotic chromosomes. The observed changes, including a number of 'secondary effects', confirm precisely with all those kinds of alterations which are typical of M-phase cells in antheridial filaments during their progression from the proliferative period of development towards terminal differentiation into sperm cells. Biological assays performed with proteinaceous extracts of maturing antheridia indicate that the activity is confined merely to a fraction containing low molecular (4.5 kDa) peptides, termed as ACCF (antheridial chromatin condensation factor). Microchemical tests showed the acidic character of ACCF and its apparent ability to form cross-links with histones and DNA-histone complexes, mediated presumably by disulfide bridges. The characteristic punctate distribution of vesicles within the cytoplasm suggests the internalization of rhodamine-isothiocyanate labelled ACCF (ACCF-TRITC) by endocytosis, implying possible sequestering and nuclear translocation upon release from the endosomal/lysosomal compartment of the cell. Copyright 1998 Academic Press.

Cell cycle arrest in antheridial extract-treated root meristems of Allium cepa and Melandrium noctiflorum.

Previous results have demonstrated that extracts derived from maturing male sex organs of Chara tomentosa are capable of inducing profound structural and functional effects upon M-phase cells in the primary root meristems of Melandrium noctiflorum and Allium cepa. Evident changes produced by a putative factor engaged in morphogenesis of antheridial filaments are manifested by: (1) significant shortening of chromosomes, (2) decreased mitotic indices, and (3) altered proportions estimated for the prophase and telophase transit times. The present image analysis of late G2 phase nuclei in antheridial filaments of C. tomentosa supports the concepts that progressive changes of their functional activities correspond closely to the increasing proportion of condensed chromatin. Cytophotometric measurements of Feulgen-stained cell nuclei in root meristems after a prolonged incubation in antheridial extracts revealed that cells which previously divided asynchronously became preferentially arrested in G1 (M. noctiflorum) and G2 (A. cepa). The stages at which the cells arrest are supposed to counterpart restriction checkpoints that prevent the initiation of DNA synthesis and mitosis. This assumption has been confirmed by autoradiographic studies using 3H-thymidine. In terms of the "Principal Control Points" (PCP) hypothesis, the obtained results suggest that two PCPs regulate G1-->S and G2-->M transition in a nuclear structure-dependent and a species-specific manner. Although in antheridial extract-treated roots of both M. noctiflorum and A. cepa there are only slight changes in the levels of chromatin condensation, the relative proportions of G1- and G2-arrested cells and their nuclear density profiles differ, as compared with the control and carbohydrate-starved plants.

GA3 content in antheridia of Chara vulgaris at the proliferative stage and in spermiogenesis estimated by capillary electrophoresis.

In male sex organs of Chara vulgaris L., the gibberellic acid (GA3), was identified by capillary zone electrophoresis. The antheridia at cell division stage of antheridial filaments leading to formation of spermatids contain 0.09 microg GA3 per antheridium, i.e. 5.3 times more than antheridia at differentiation stage of spermatozoids (spermiogenesis). Spermiogenesis is not regulated by gibberellins.

Overcoming enzymatic resistance in bacteria: impact on future therapy.

Resistance of bacteria to antibiotics often involves inactivating enzymes. One approach developed to overcome this mechanism of resistance consists of combining an efficient but possibly unstable antibiotic with a powerful inhibitor of the inactivating enzyme. Attempts have been made with different antibiotics but significant success has only been obtained with the beta-lactams, clavulanic acid and sulbactam being the only compounds currently being used clinically. Sulbactam, a time-dependent irreversible inhibitor of plasmid-mediated penicillinases and of chromosomally mediated penicillinases and cephalosporinases, potentiates the antibacterial activity of beta-lactams but only exhibits a moderate antibacterial activity, which is related to its affinity for the lethal targets of the beta-lactams--the penicillin-binding proteins. In bacterial strains that produce either low amounts of beta-lactamase, or none at all, a synergistic effect can be observed when sulbactam is associated with a beta-lactam antibiotic that has a complementary affinity for the target sites.

Differences between clavulanic acid and sulbactam in induction and inhibition of cephalosporinases in enterobacteria.

The ability of clavulanic acid and sulbactam to induce and inhibit cephalosporinases was evaluated in 16 clinical isolates of enterobacteria. Using the quantitative induction assay, the checkerboard method and the disc approximation test, clavulanic acid was shown to act as inducer for all species, whereas sulbactam only induced strains of Providencia stuartii. Antagonism was achieved using a combination of clavulanic acid and cefotaxime but a combination of sulbactam and cefotaxime was either synergistic or indifferent. This variation in effect was probably due to the fact that sulbactam, but not clavulanic acid could inhibit cephalosporinases. The data revealed a significant difference between sulbactam and clavulanic acid, which may have relevance to their relative usefulness in combination with beta-lactam antibiotics for the treatment of infections due to enterobacteria that produce inducible cephalosporinase.

[Urinary infection and its development. Current diagnostic biological data]. / L'infection urinaire et son évolution. Données biologiques actuelles de diagnostic

The main object of the present article was to show that, independently of the clinical symptoms, the results of three laboratory examinations permit one to make the diagnosis of urinary infection and its degree of severity. 1) Bacteriuria equal or greater than 10(3) bacteria per ml is already significant of an urinary infection and infection of tissues of the urinary tree. If leukocyturia accompanies this bacteriuria, this does not necessarily show the degree of the infection. 2) The demonstration of specific serum antibodies of the bacterial species responsible for the infection (agglutination technique) is evidence of infection of tissues of the urinary tree, sometimes before the onset of radiological lesions. Furthermore, supervision of the course of the titer of these antibodies assesses the efficacy of the antibiotic treatment undertaken. 3) Using an immunofluorescent technique, the discovery of bacteria antibody immune complexes in the urinary sediment is also a sign of infection of the tissues of the urinary tree.