Service-Aware Clustering: An Energy-Efficient Model for the Internet-of-Things.

Current generation wireless sensor routing algorithms and protocols have been designed based on a myopic routing approach, where the motes are assumed to have the same sensing and communication capabilities. Myopic routing is not a natural fit for the IoT, as it may lead to energy imbalance and subsequent short-lived sensor networks, routing the sensor readings over the most service-intensive sensor nodes, while leaving the least active nodes idle. This paper revisits the issue of energy efficiency in sensor networks to propose a clustering model where sensor devices' service delivery is mapped into an energy awareness model, used to design a clustering algorithm that finds service-aware clustering (SAC) configurations in IoT settings. The performance evaluation reveals the relative energy efficiency of the proposed SAC algorithm compared to related routing algorithms in terms of energy consumption, the sensor nodes' life span and its traffic engineering efficiency in terms of throughput and delay. These include the well-known low energy adaptive clustering hierarchy (LEACH) and LEACH-centralized (LEACH-C) algorithms, as well as the most recent algorithms, such as DECSA and MOCRN.

Rapid synthesis of new DNMT inhibitors derivatives of procainamide.

DNA methyltransferases (DNMTs) are responsible for DNA methylation, an epigenetic modification involved in gene regulation. Families of conjugates of procainamide, an inhibitor of DNMT1, were conceived and produced by rapid synthetic pathways. Six compounds resulted in potent inhibitors of the murine catalytic Dnmt3A/3L complex and of human DNMT1, at least 50 times greater than that of the parent compounds. The inhibitors showed selectivity for C5 DNA methyltransferases. The cytotoxicity of the inhibitors was validated on two tumour cell lines (DU145 and HCT116) and correlated with the DNMT inhibitory potency. The inhibition potency of procainamide conjugated to phthalimide through alkyl linkers depended on the length of the linker; the dodecane linker was the best.

Physicochemical Characterization of Detarium microcarpum Seeds from Northern Benin.

The objective of this work is to determine the physicochemical characteristics of the Detarium microcarpum seeds from North Benin, specially the proximate composition, colour, minerals, and antinutritional factors using standard analytical methods. The results show that the contents of moisture, protein, total sugars, lipid, crude fiber, and ash ranged, respectively, from 10.85 to 14.69%, from 13.54 to 17.82%, from 19.69 to 32.04%, from 8.68 to 11.90%, from 19.78 to 34.24%, and from 1.5 to 3.49%. The luminance (l∗), red saturation (a∗), and yellow saturation (b∗) have, respectively, ranged from 60.45 to 67.64, from 5.44 to 8.86, and from 8.24 to 9.28. Seeds contain interesting contents of potassium, calcium, magnesium, manganese, sodium, and iron; they have, respectively, varied from 6141.88 to 12305.16 mg/kg, from 1254.47 to 2168.62 mg/kg, from 1298.87 to 2533.06 mg/kg, from 75.18 to 307.23 mg/kg, from 53.52 to 136.19 mg/kg, and from 28.46 to 181.42 mg/kg. The investigation of antinutritional factors indicates the presence of oxalates, phytates, total phenolic compounds, and saponins with contents that have varied, respectively, from 1.01 to 2.36%, from 0.37 to 0.87%, from 3.13 to 7.61%, and from 1.35 to 4.59%. On average, the physicochemical characteristics of the Sudanian and Sudano-Guinean zones are similar, except for total sugar content.

Biofilm-induced modifications in the proteome of Pseudomonas aeruginosa planktonic cells.

While recent studies focused on Quorum Sensing (QS) role in the cell-to-cell communication in free or biofilm cultures, no work has been devoted up to now to investigate the communication between sessile and planktonic bacteria. In this aim, we elaborated an original two-chambered bioreactor and used a proteomic approach to study the alterations induced by Pseudomonas aeruginosa biofilm cells on protein expression in planktonic counterparts (named SIPs for Surface-Influenced Planktonics). Proteomic analyses revealed the existence of 31 proteins whose amount varied in SIPs, among which five corresponded to hypothetic proteins and two (the Fur and BCP proteins) are involved in bacterial response to oxidative stress. An increase in the concentration of C(4)-HSL (rhlR-rhlI-dependent QS) and 3-oxo-C(12)-HSL (lasR-lasI-dependent QS) autoinducer molecules was shown in the planktonic compartment. Interestingly, among proteins that were accumulated by SIPs was 3-oxoacyl-[acyl-carrier-protein] reductase, a protein involved in the production of the autoinducer 3-oxo-C(12)-HSL. These results demonstrate that planktonic organisms are able to detect the presence of a biofilm in their close environment and to modify their gene expression in consequence.

Identification of a novel hantavirus strain in the root vole (Microtus oeconomus) in Lithuania, Eastern Europe.

Hantaviruses are zoonotic pathogens that can cause subclinical to lethal infections in humans. In Europe, five orthohantaviruses are present in rodents: Myodes-associated Puumala orthohantavirus (PUUV), Microtus-associated Tula orthohantavirus, Traemmersee hantavirus (TRAV)/ Tatenale hantavirus (TATV)/ Kielder hantavirus, rat-borne Seoul orthohantavirus, and Apodemus-associated Dobrava-Belgrade orthohantavirus (DOBV). Human PUUV and DOBV infections were detected previously in Lithuania, but the presence of Microtus-associated hantaviruses is not known. For this study we screened 234 Microtus voles, including root voles (Microtus oeconomus), field voles (Microtus agrestis) and common voles (Microtus arvalis) from Lithuania for hantavirus infections. This initial screening was based on reverse transcription-polymerase chain reaction (RT-PCR) targeting the S segment and serological analysis. A novel hantavirus was detected in eight of 79 root voles tentatively named "Rusne virus" according to the capture location and complete genome sequences were determined. In the coding regions of all three genome segments, Rusne virus showed high sequence similarity to TRAV and TATV and clustered with Kielder hantavirus in phylogenetic analyses of partial S and L segment sequences. Pairwise evolutionary distance analysis confirmed Rusne virus as a strain of the species TRAV/TATV. Moreover, we synthesized the entire nucleocapsid (N) protein of Rusne virus in Saccharomyces cerevisiae. We observed cross-reactivity of antibodies raised against other hantaviruses, including PUUV, with this new N protein. ELISA investigation of all 234 voles detected Rusne virus-reactive antibodies exclusively in four of 79 root voles, all being also RNA positive, but not in any other vole species. In conclusion, the detection of Rusne virus RNA in multiple root voles at the same trapping site during three years and its absence in sympatric field voles suggests root voles as the reservoir host of this novel virus. Future investigations should evaluate host association of TRAV, TATV, Kielder virus and the novel Rusne virus and their evolutionary relationships.

Polysaccharide-based chromatographic adsorbents for virus purification and viral clearance.

Viruses still pose a significant threat to human and animal health worldwide. In the fight against viral infections, high-purity viral stocks are needed for manufacture of safer vaccines. It is also a priority to ensure the viral safety of biopharmaceuticals such as blood products. Chromatography techniques are widely implemented at both academic and industrial levels in the purification of viral particles, whole viruses and virus-like particles to remove viral contaminants from biopharmaceutical products. This paper focuses on polysaccharide adsorbents, particulate resins and membrane adsorbers, used in virus purification/removal chromatography processes. Different chromatographic modes are surveyed, with particular attention to ion exchange and affinity/pseudo-affinity adsorbents among which commercially available agarose-based resins (Sepharose®) and cellulose-based membrane adsorbers (Sartobind®) occupy a dominant position. Mainly built on the development of new ligands coupled to conventional agarose/cellulose matrices, the development perspectives of polysaccharide-based chromatography media in this antiviral area are stressed in the conclusive part.

Polysaccharides against Viruses: Immunostimulatory Properties and the Delivery of Antiviral Vaccines and Drugs.

Because viruses still represent a significant threat to human and animal health worldwide, the development of effective weapons against viral infections remains a top priority for the biopharmaceutical industry. This article reviews the dietary and pharmaceutical applications of polysaccharides (PS), first of all chitosan, in the prevention and treatment of viral diseases, focusing more particularly on solid or gel micro/nanoparticulate systems. The intrinsic antiviral activity of PS and their immunostimulatory effects, implemented in animal and human diets, are first surveyed. Then the review discusses the potential of PS-based particles as carriers of antiviral drugs and vaccines, with emphasis on the adjuvant potency of PS in solid vaccine formulations. The gap between the abundance of academic studies in this area and the lack of actual antiviral formulations dispensed to human patients is underlined, notwithstanding a number of branded products on the market.

Cellulose-based virus-retentive filters: a review.

Viral filtration is a critical step in the purification of biologics and in the monitoring of microbiological water quality. Viral filters are also essential protection elements against airborne viral particles. The present review first focuses on cellulose-based filter media currently used for size-exclusion and/or adsorptive filtration of viruses from biopharmaceutical and environmental water samples. Data from spiking studies quantifying the viral filtration performance of cellulosic filters are detailed, i.e., first, the virus reduction capacity of regenerated cellulose hollow fiber filters in the manufacturing process of blood products and, second, the efficiency of virus recovery/concentration from water samples by the viradel (virus adsorption-elution) method using charge modified, electropositive cellulosic filters or conventional electronegative cellulose ester microfilters. Viral analysis of field water samples by the viradel technique is also surveyed. This review then describes cellulose-based filter media used in individual protection equipment against airborne viral pathogens, presenting innovative filtration media with virucidal properties. Some pros and cons of cellulosic viral filters and perspectives for cellulose-based materials in viral filtration are underlined in the review.

Polysaccharide-based antibiofilm surfaces.

Surface treatment by natural or modified polysaccharide polymers is a promising means to fight against implant-associated biofilm infections. The present review focuses on polysaccharide-based coatings that have been proposed over the last ten years to impede biofilm formation on material surfaces exposed to bacterial contamination. Anti-adhesive and bactericidal coatings are considered. Besides classical hydrophilic coatings based on hyaluronic acid and heparin, the promising anti-adhesive properties of the algal polysaccharide ulvan are underlined. Surface functionalization by antimicrobial chitosan and derivatives is extensively surveyed, in particular chitosan association with other polysaccharides in layer-by-layer assemblies to form both anti-adhesive and bactericidal coatings. STATEMENT OF SIGNIFICANCE: Bacterial contamination of surfaces, leading to biofilm formation, is a major problem in fields as diverse as medicine, first, but also food and cosmetics. Many prophylactic strategies have emerged to try to eliminate or reduce bacterial adhesion and biofilm formation on surfaces of materials exposed to bacterial contamination, in particular implant materials. Polysaccharides are widely distributed in nature. A number of these natural polymers display antibiofilm properties. Hence, surface treatment by natural or modified polysaccharides is a promising means to fight against implant-associated biofilm infections. The present manuscript is an in-depth look at polysaccharide-based antibiofilm surfaces that have been proposed over the last ten years. This review, which is a novelty compared to published literature, will bring well documented and updated information to readers of Acta Biomaterialia.

How Big of a Problem is Analytic Error in Secondary Analyses of Survey Data?

Secondary analyses of survey data collected from large probability samples of persons or establishments further scientific progress in many fields. The complex design features of these samples improve data collection efficiency, but also require analysts to account for these features when conducting analysis. Unfortunately, many secondary analysts from fields outside of statistics, biostatistics, and survey methodology do not have adequate training in this area, and as a result may apply incorrect statistical methods when analyzing these survey data sets. This in turn could lead to the publication of incorrect inferences based on the survey data that effectively negate the resources dedicated to these surveys. In this article, we build on the results of a preliminary meta-analysis of 100 peer-reviewed journal articles presenting analyses of data from a variety of national health surveys, which suggested that analytic errors may be extremely prevalent in these types of investigations. We first perform a meta-analysis of a stratified random sample of 145 additional research products analyzing survey data from the Scientists and Engineers Statistical Data System (SESTAT), which describes features of the U.S. Science and Engineering workforce, and examine trends in the prevalence of analytic error across the decades used to stratify the sample. We once again find that analytic errors appear to be quite prevalent in these studies. Next, we present several example analyses of real SESTAT data, and demonstrate that a failure to perform these analyses correctly can result in substantially biased estimates with standard errors that do not adequately reflect complex sample design features. Collectively, the results of this investigation suggest that reviewers of this type of research need to pay much closer attention to the analytic methods employed by researchers attempting to publish or present secondary analyses of survey data.

French multicentric survey of outcome of pregnancy in women with pregestational diabetes.

OBJECTIVE: To evaluate perinatal outcome in pregnancies in women with type 1 and type 2 diabetes and the influence of preconception care 10 years after the St. Vincent's declaration. RESEARCH DESIGN AND METHODS: A cross-sectional study was conducted in 12 perinatal centers in France in 2000-2001. The main investigated outcomes were perinatal mortality, major congenital malformations, and preterm delivery. RESULTS: Among 435 single pregnancies, 289 (66.4%) were from women with type 1 and 146 (33.6%) from women with type 2 diabetes. Perinatal mortality rate was 4.4% (0.7% national rate), severe congenital malformations rate was 4.1% (2.2% national rate), and preterm delivery rate was 38.2% (4.7% national rate). Preconception care was provided in 48.5% women with type 1 diabetes and in 24.0% women with type 2 diabetes. Women whose first trimester HbA(1c) was >8% had higher rates of perinatal mortality (9.2 vs. 2.5%; odds ratio 3.9; 95% CI 1.5-9.7; P < 0.005), major congenital malformations (8.3 vs. 2.5%; 3.5; 1.3-8.9; P < 0.01), and preterm delivery (57.6 vs. 24.8%; 1.4; 1.1-1.7; P < 0.005) than those with first trimester HbA(1c) <8%. These results are similar to those reported in France in 1986-1988. CONCLUSIONS: Pregnancies in women with diabetes are still poorly planned and complicated by higher rates of perinatal mortality and major congenital malformations. Despite knowledge of the importance of intensified glycemic control before pregnancy, reaching the St. Vincent's target needs further implementation in France.

Immobilized viable microbial cells: from the process to the proteome em leader or the cart before the horse.

Biotechnological processes based on immobilized viable cells have developed rapidly over the last 30 years. For a long time, basic studies of the physiological behaviour of immobilized cells (IC) have remained in the shadow of the applications. Natural IC structures, i.e. biofilms, are being increasingly investigated at the cellular level owing to their definite importance for human health and in various areas of industrial and environmental relevance. This review illustrates this paradoxical development of research on ICs, starting from the initial rationale for IC emergence and main application fields of the technology--with particular emphasis on those that exploit the extraordinary resistance of ICs to antimicrobial compounds--to recent advances in the proteomic approach of IC physiology.

Multiple regression modelling of mineral base oil biodegradability based on their physical properties and overall chemical composition.

A set of 38 mineral base oils was characterized by a number of chemical (i.e., overall chemical composition) and physical parameters used routinely in industry. Their primary biodegradability was evaluated using the CEC L-33-A-93 test. Multiple (stepwise) linear regression (MLR) analyses were performed to describe the relationships between the biodegradability values and the chemical or physical properties of oils. Chemical, physical, and both types of parameters were successively used as independent variables. Using chemical descriptors as variables, a four-variable model equation was obtained that explained only 68.2% (adjusted R-squared statistic=68.2%) of the variability in biodegradability. The fitting was improved by using either the physical or the whole parameters as variables. MLR analyses led to three-descriptor model equations involving kinematic viscosity (as log), Noack volatility (as log) and either the viscosity index (pure physical model) or the paraffinic carbon percentage (mixed chemical-physical model). These two models displayed very similar adjusted R-squared statistics, of approximately 91%. Their predicting ability was verified using 25 additional base oils or oil blends. For 80% of oils on a total of 63, the absolute percentage error on biodegradability predicted by either model was lower than 20%. Kinematic viscosity was by far the most influential parameter in the two models.

Comparative chemical study and cytotoxic activity of Uvariodendron angustifolium essential oils from Benin.

This study aimed to compare the chemical composition of volatile extracts obtained by hydrodistillation of leaves, stems, bark and roots of Uvariodendron angustifolium (Engl. & Diels) R. E. Fries. The essential oils, obtained with yields between 0.12 and 0.66%, were analyzed by GC/FID and GC/MS. A great variability in the chemical composition was observed depending on the plant part treated. The essential oils obtained from leaves and stems contained mainly neral (29.7-30.5%) and geranial (42.9-47.3%), while methyl eugenol was the major component of the volatile extracts from bark (68.3%) and roots (85.3%). Interesting cytotoxic properties of these essential oils on human breast cancer cells MCF-7 were demonstrated.

Proteomic analysis of Staphylococcus aureus biofilms grown in vitro on mechanical heart valve leaflets.

The in vitro colonization of three commercial heart valve leaflets by Staphylococcus aureus was investigated. The leaflets, made of pyrolytic carbon alloyed with or without silicon, displayed similar surface properties (wettability, roughness) and were readily colonized by S. aureus that formed patchy biofilms on the three supports. A proteomic approach was used to assess the physiological status of biofilm populations by comparing their protein maps to those of bacteria cultured as free cells in the presence or absence of biofilm substratum. Principal component analysis (PCA) revealed, for each tested leaflet, statistical relationships between the protein maps of the biofilm and free-floating microbial populations. A spot-by-spot comparison of protein levels on two-dimensional electropherograms showed that many proteins were accumulated or underproduced by microbial populations grown in the presence of a leaflet compared with protein levels in control free populations. The number of accumulated proteins was noticeably higher than that of underproduced polypeptides. This protein overproduction was emphasized in biofilm populations. Several proteins, some of which were identified, were differentially produced by both surface-associated planktonic and biofilm-grown cell populations compared with control free-cell ones cultured in the absence of leaflet, whatever the leaflet tested. The potential of this proteomic approach for fighting against microbial adhesion and biofilm formation is discussed.

Impact of rpoS deletion on the proteome of Escherichia coli grown planktonically and as biofilm.

To investigate the role of rpoS in gene expression of Escherichia coli cells grown as biofilms, we compared the proteomes of a rpoS mutant and the wild-type strain. Experiments were performed on planktonic cells (in exponential or stationary growth phase) and biofilms developed on glass wool. Spot-by-spot comparison of gels obtained from biofilm and planktonic wild-type organisms showed that the intensity of between 22 and 30% of detected spots was affected by the growth mode, depending of the control used. Principal component analysis, used to interpret the variations in protein spot densities, discriminated exponential-phase cells (wild-type and mutant) from the other incubation conditions and secondarily 72-old cultures. The statistical analysis demonstrated that the rpoS mutation did not significantly modify the proteome of exponential-growth phase cells, the differences involving only 3% of the proteome. However, increasing the incubation time from 8 to 72 h noticeably increased the number of changed proteins. A cluster analysis showed that RpoS plays a role in the special nature of the gene expression of biofilm cells but lower than in stationary-phase bacteria. We identified 35 rpoS-regulated proteins that were already or not described as controlled by this sigma factor. For some of them, the mode of regulation by RpoS was obviously dependent on the culture condition (planktonic vs biofilm).

Identification of biofilm-associated cluster (bac) in Pseudomonas aeruginosa involved in biofilm formation and virulence.

Biofilms are prevalent in diseases caused by Pseudomonas aeruginosa, an opportunistic and nosocomial pathogen. By a proteomic approach, we previously identified a hypothetical protein of P. aeruginosa (coded by the gene pA3731) that was accumulated by biofilm cells. We report here that a Delta pA3731 mutant is highly biofilm-defective as compared with the wild-type strain. Using a mouse model of lung infection, we show that the mutation also induces a defect in bacterial growth during the acute phase of infection and an attenuation of the virulence. The pA3731 gene is found to control positively the ability to swarm and to produce extracellular rhamnolipids, and belongs to a cluster of 4 genes (pA3729-pA3732) not previously described in P. aeruginosa. Though the protein PA3731 has a predicted secondary structure similar to that of the Phage Shock Protein, some obvious differences are observed compared to already described psp systems, e.g., this unknown cluster is monocistronic and no homology is found between the other proteins constituting this locus and psp proteins. As E. coli PspA, the amount of the protein PA3731 is enlarged by an osmotic shock, however, not affected by a heat shock. We consequently named this locus bac for biofilm-associated cluster.

Protein expression in Escherichia coli S17-1 biofilms: impact of indole.

Bacteria undergo significant changes during adherence to surfaces and biofilm development. Cell-to-cell signalling molecules are known to be involved in these phenotypic adaptations to the sessile mode of life. We demonstrated previously that indole can act as an extracellular signal to regulate biofilm formation in E. coli. To identify proteins over- or under-expressed in response to E. coli biofilm formation and indole signalling, we compared the proteomes of the E. coli S17-1 wild-type and 3714 (S17-1 tnaA::Tn5) tryptophanase-negative mutant cells (which don't produce indole) grown as suspensions or biofilms in the presence or absence of exogenous indole. From computer-assisted image analysis, 407 spots were discriminated on two-dimensional electropherograms. Principal component analysis (PCA) of the electropherograms did not discriminate between the proteomes of the wild-type and mutant cells grown as suspensions indicating that indole has a limited impact onto protein expression of planktonic cells. The first principal component extracted by PCA, after standardization of the observations, opposed planktonic and biofilm cells confirming the existence of changes in protein expression during E. coli biofilm formation. Among proteins over- or under-expressed by both sessile wild-type and mutant cells, we identified metabolic enzymes, transporters, proteins involved in the translation and transcription machinery, stress response and regulation, and signalling proteins. The wild-type and mutant strains grown as biofilms in the presence of indole were discriminated by the second component. The role of some proteins whose expression was altered in biofilm bacteria compared to suspended counterparts is discussed.

Impact of rigidification on relaxometric properties of a tricyclic tetraazatriacetic gadolinium chelate.

A constrained derivative of Gd-PCTA12, Gd-cyclo-PCTA12, in which one ethylene bridge connecting two nitrogen atoms of the triamine block is replaced by a cyclohexylene bridge, was synthesized and the impact of rigidification was studied by comparing the physicochemical and relaxometric properties of both gadolinium MRI contrast agents, Gd-PCTA12 and Gd-cyclo-PCTA12. The new complex has higher proton relaxivity than the parent compound (r(1) = 6.1 s(-1) mM(-1) at 20 MHz and 310 K). The rigidification of the PCTA12 scaffold proved to have no impact on the inertness towards transmetallation by endogenous ions such as Zn(2+). Moreover, for both contrast agents, the relaxivity was not quenched by endogenous anions. The oxygen-17 NMR study and the NMRD profile demonstrated that the rigidification of the PCTA scaffold had no impact on the electronic relaxation of Gd-cyclo-PCTA12. However, the rigidity of this complex induced an acceleration of the exchange rate of the inner-sphere water molecules as a result of steric crowding around the gadolinium ion. The value of tau(M) (310) thus approached the optimal value required to attain high relaxivity once the chelate is immobilized by covalent or non-covalent binding to macromolecules.

Immobilization induces alterations in the outer membrane protein pattern of Yersinia ruckeri.

We compared the outer membrane protein (OMP) pattern of 2-day-old immobilized Yersinia ruckericells (IC) with that of early (FC24) and late (FC48) stationary-phase planktonic counterparts. Fifty-five OMPs were identified. Principal component analysis discriminated between the protein maps of FC and IC. Some OMPs involved in bacterial adaptation were accumulated by both FC48 and IC but the expression of other proteins was controlled by the sessile mode of growth.