Upstream modes and antidots poison graphene quantum Hall effect.

The quantum Hall effect is the seminal example of topological protection, as charge carriers are transmitted through one-dimensional edge channels where backscattering is prohibited. Graphene has made its marks as an exceptional platform to reveal new facets of this remarkable property. However, in conventional Hall bar geometries, topological protection of graphene edge channels is found regrettably less robust than in high mobility semi-conductors. Here, we explore graphene quantum Hall regime at the local scale, using a scanning gate microscope. We reveal the detrimental influence of antidots along the graphene edges, mediating backscattering towards upstream edge channels, hence triggering topological breakdown. Combined with simulations, our experimental results provide further insights into graphene quantum Hall channels vulnerability. In turn, this may ease future developments towards precise manipulation of topologically protected edge channels hosted in various types of two-dimensional crystals.

Immigration and adolescent health: the case of a multicultural population.

OBJECTIVES: Previous research indicates that the impact of immigration on health tends to be specific as it is influenced by many factors such as life stage and host country. The aim of this study was to examine the relationship between immigration and adolescent health within the multicultural context of the Brussels-Capital Region in Belgium. STUDY DESIGN: The study was based on the 2014 Health Behaviour in School-aged Children survey. The sample consisted of 2962 adolescents from the fifth grade of primary to the last grade of secondary schools in Brussels. METHODS: Associations between health indicators and immigration status were analysed using multivariable logistic regression models adjusted for sociodemographic characteristics. RESULTS: Natives, first-generation immigrants, second-generation immigrants with both parents born abroad and second-generation immigrants with one parent born abroad represented 19%, 23%, 36% and 22% of the respondents, respectively. Sociodemographic characteristics and health behaviours varied according to immigrant status. Young immigrants were more likely to present overweight (odds ratio [OR] first-generation immigrants vs. natives = 1.76 [95% confidence interval {CI} = 1.16-2.65]; OR second-generation immigrants with both parents born abroad vs. natives = 2.06 [95% CI = 1.41-3.02]; OR second-generation immigrants with one parent born abroad vs. natives = 1.69 [95% CI = 1.12-2.56]). This effect turned out to be partially explained by sociodemographic status and health-related behaviours. No association was detected between immigration and self-rated health and multiple recurrent symptoms. CONCLUSIONS: Discrepancies in health behaviours and weight status were identified between adolescents of different immigration background, whereas this was not the case for well-being. Socio-economic status, cultural characteristics and specific behaviours partly explained these findings. Future research is needed to better understand immigration-related risk and protective factors, at individual and school levels.

[Secondary facial recontouring with micro-porous titanium implants]. / Corrections secondaires de la face par implants en titane.

Facial recontouring has always been a longstanding objective of esthetic or reconstructive surgery. Most often it uses two types of surgical techniques: autologous and alloplastic. In that regard, different surgical techniques have been proposed to enhance facial recontouring. MATERIALS AND METHODS: Through 5 clinical case reports and a literature review, this article explores the use of allopastic microporous titanium implants in secondary volumetric corrections of the face. RESULTS: There is a current lack of evidence regarding the use of microporous titanium implants in volumetric corrections of the face, most papers reporting their use in post-traumatic or post-surgical cranio-facial defects repair. DISCUSSION: Pros and cons of such implants are discussed in association with the usefulness of this surgical technique in daily surgical practice.

A rare ectopic localization of pleomorphic adenoma.

INTRODUCTION: Pleomorphic adenoma (PA) is the most common benign salivary gland tumor, frequently affecting the major salivary glands but also the palatal or labial minor salivary glands. Pleomorphic adenomas affecting the retromolar trigone have seldom been reported with only few cases described in the literature. OBSERVATION: We present the case of a young female patient who presented with this rare localization of pleomorphic adenoma and its subsequent management. DISCUSSION: Pleomorphic adenoma of the retromolar trigone is a rare occurrence. Nevertheless, when faced with a swelling of the retromolar trigone, a diagnosis of pleomorphic adenoma should not be omitted from the differential.

Comparing impact on the family and insurance coverage in children with cerebral palsy and children with another special healthcare need.

BACKGROUND: Families and caregivers of children with special healthcare needs (CSHCN) often experience financial difficulties, have unmet physical and mental health needs, and are at increased risk of marital problems due to the stress caused by carrying for their child. Within the larger population of CHSCN, young people with cerebral palsy (CP) have more unmet needs due to the complexity and potential severity of the disability. The purpose of this study was to identify factors associated with differences in insurance coverage and impact on the family of children with CP and other CHSCN. METHODS: The data were taken from the National Survey of Children with Special Health Care Needs, which was designed to examine state- and national-level estimates of CSHCN. Three variables examined differences in insurance coverage between those children diagnosed with CP versus all other CSHCN: insurance coverage for the previous year, current insurance coverage, and adequacy of insurance coverage. Four variables representing different indicators of family impact were used to assess differences between children with CP versus all other CSHCN: out-of-pocket expenses for healthcare, family financial burden, hours per week that family members spent caring for the child, and impact on family work life. RESULTS: The results of this study showed significant differences between households with a child with CP and a child with another health special need in terms of insurance coverage, indicating a tendency of children with CP to be insured the entire year. As for the impact on the family in households with children with CP versus other CSHCN, there were significant differences in all four variables that were analysed. CONCLUSIONS: There is limited evidence highlighting differences between the impact of caring for a child with CP and caring for other CSHCN. Caring for a child with CP has a significant impact on the family, despite insurance coverage.

Neuropathic pain in the orofacial region: The role of pain history. A retrospective study.

INTRODUCTION: Orofacial neuropathic pain is often difficult to treat, mostly because of still unclear underlying mechanisms. The occurrence of such neuropathic pain varies depending on different factors, of which preexisting preoperative pain seems to be of high importance. The aim of this study was thus to test the hypothesis that prior history of pain could indeed be considered a risk factor for the development of orofacial neuropathic pain in the same region. METHODS: The study was performed in the dental department of the Groupe Hospitalier Pitié-Salpêtrière (GHPS) in Paris, France. We investigated the presence of prior inflammatory pain before development of orofacial neuropathic pain in 56 patients. For each patient file, the following items were collected: age, gender; medical history; diagnosis; description of the pain (at time of consultation); presence or absence of prior dental treatment; date and type of dental treatment received. RESULTS: 41 patients (73%) of orofacial neuropathic pain patients had a history of pain compatible with an inflammatory condition; 4% (n=2) did not report any prior pain and 23% (n=13) could not remember. Among the patients with documented history of pain prior to neuropathy, 88% (n=36) received surgical treatment; 61%, (n=25) endodontic treatment and 22%, (n=9) restorative treatment. All eventually received endodontic treatment or tooth extraction. These dental treatments are compatible with the hypothesis of prior inflammatory pain in these patients. CONCLUSION: These results support the hypothesis that prior inflammatory pain could favor the development of orofacial neuropathic pain. Prevention and treatment of inflammatory trigeminal pain may therefore play a key role in preventing future neuropathic pain development.

Hedgehog Pathway-Mediated Vascular Alterations Following Trigeminal Nerve Injury.

Whereas neurovascular interactions in spinal neuropathic pain models have been well characterized, little attention has been given to such neurovascular interactions in orofacial neuropathic pain models. This study investigated in male Sprague-Dawley rats the vascular changes following chronic constriction injury (CCI) of the infraorbital nerve (IoN), a broadly validated preclinical model of orofacial neuropathic pain. Following IoN-CCI, an early downregulation of tight junction proteins Claudin-1 and Claudin-5 was observed within the endoneurium and perineurium, associated with increased local accumulation of sodium fluorescein (NaFlu) within the IoN parenchyma, as compared with sham animals. These events were evidence of local blood-nerve barrier disruption and increased vascular permeability. A significant upregulation of immunocytes (CD3, CD11b) and innate immunity (TLR2, TLR4) mRNA markers was also observed, suggestive of increased local inflammation. Finally, a significant downregulation of Hedgehog pathway readouts Patched-1 and Gli-1 was observed within the IoN after CCI and local injections of cyclopamine, a Hedgehog pathway inhibitor, replicated in naïve rats the molecular, vascular, and behavioral changes observed following IoN-CCI. These results suggest a major role of Hedgehog pathway inhibition in mediating local increased endoneurial and perineurial vascular permeability following trigeminal nerve injury, thus facilitating immunocytes infiltration, neuroinflammation development, and neuropathic pain-like aversive behavior.

Evaluation of initial dofetilide dosing recommendation based on actual body weight in overweight and obese patients.

WHAT IS KNOWN AND OBJECTIVE: The dofetilide label recommends using actual body weight (ABW) to calculate the Cockcroft-Gault creatinine clearance (CrCl) for the determination of the initial dose; however, few studies have attempted to evaluate this dosing recommendation in overweight and obese patients. We evaluated whether the current dofetilide dosing recommendation based on ABW is appropriate in overweight and obese patients. METHODS: This is a retrospective cohort study conducted at two large academic medical centres in the United States on overweight and obese patients (body mass index ≥ 25 kg/m(2)) who were newly started on dofetilide based on ABW. Patients were categorized into (i) the different-dose group if their CrCl calculated based on the ideal body weight (IBW) resulted in a lower initial dofetilide dose compared with ABW-based CrCl and (ii) the same-dose group if they would have the same initial dose based on IBW and ABW. The primary outcome was dofetilide dose reduction or discontinuation due to prolongation of the corrected QT interval during the first 3 days of dofetilide therapy. Multivariable logistic regression analysis was performed to identify factors predicting the risk of primary outcome. RESULTS AND DISCUSSION: Of the 132 patients included in the study, 29 (22·0%) were in the different-dose group and 40 (30·3%) had the primary outcome. The per cent of patients with the primary outcome was not statistically significantly different between the different-dose and same-dose groups (37·9% vs. 28·2%; P = 0·31). Diabetes mellitus was a significant predictor for the primary outcome (odds ratio 2·54; 95% confidence interval 1·05-6·15). WHAT IS NEW AND CONCLUSION: Our study provides the evidence on the safety of the current dofetilide dosing recommendation in overweight and obese populations in clinical practice. Current ABW-based dofetilide dosing is reasonable in overweight and obese patients.

Selection of anionic exchange resins for removal of natural organic matter (NOM) fractions.

Early elimination of natural organic matter (NOM) by ion exchange (IEX) in water treatment is expected to improve subsequent water treatment processes and the final drinking water quality. Nine anionic exchange resins were investigated to remove NOM and specific NOM fractions determined by liquid chromatography in combination with organic carbon detection (LC-OCD) and fluorescence excitation-emission matrices (EEM). Breakthrough of NOM was predicted by model calculations using Freundlich isotherms and IEX rate experiments. The time to breakthrough varied from 4 to 38 days. Removal of specific NOM fractions proved to vary considerably for the different types of IEX resins, ranging from 1% to almost 60%. The removal of NOM fractions, specifically humic substances, increased with an increase in water content of the investigated IEX resins and with a decrease in resin size. The best-performing IEX resins consisted of the smallest resins and/or those with the highest water content. The worst-performing IEX resins reflected the highest exchanging capacities and the lowest water contents.

Simultaneous measurement of plasma concentrations and 13C-enrichment of short-chain fatty acids, lactic acid and ketone bodies by gas chromatography coupled to mass spectrometry.

A new method has been developed for the simultaneous measurement, in a reduced plasma sample, of concentration and 13C-isotopic enrichment of acetic, propionic, butyric, lactic, acetoacetic and beta-hydroxybutyric acids by gas chromatography coupled to mass spectrometry. After plasma deproteinisation, a diethylic extraction and a N-tert.-butyldimethylsilyl-N-methyltrifluoroacetamide derivatisation were performed. Both diethyl extraction and derivatisation procedures were optimised using the central composite designs methodology. The optimised method provides good linearity, intra-day and within-day repeatability. Except for beta-hydroxybutyric (49 microM) and acetoacetic acid (5 microM), detection limits were ranging between 0.2 and 0.7 microM allowing uses of this method for colonic metabolism studies.

NUDC expression during amphibian development.

To identify gene products important for gastrulation in the amphibian Pleurodeles waltl, a screen for regional differences in new protein expression at the early gastrula stage was performed. A 45 kDa protein whose synthesis was specific for progenitor endodermal cells was identified. Microsequencing and cDNA cloning showed that P45 is highly homologous to rat NUDC, a protein suggested to play a role in nuclear migration. Although PNUDC can be detected in all regions of the embryo, its de novo synthesis is tightly regulated spatially and temporally throughout oogenesis and embryonic development. New PNUDC synthesis in the progenitor endodermal cells depends on induction by the mesodermal cells in the gastrula. During development, PNUDC is localized in the egg cortical cytoplasm, at the cleavage furrow during the first embryonic division, around the nuclei and cortical regions of bottle cells in the gastrula, and at the basal region of polarized tissues in the developing embryo. These results show for the first time the expression and compartmentalization of PNUDC at distinct stages during amphibian development.

Synthesis and activities of pyoverdin-quinolone adducts: a prospective approach to a specific Therapy against Pseudomonas aeruginosa.

Pseudomonas aeruginosa is particularly resistant to most all the antibiotics presently available, essentially because of the very low permeability of its outer membrane. To overcome this, we synthesized four siderophore-based antibiotics formed by two quinolones - norfloxacin and benzonaphthyridone - bound to the pyoverdin of P. aeruginosa ATCC 15692 via two types of spacer arms: one stable and the other readily hydrolyzable. From the comparison of their antibacterial properties with those of the two unbound quinolones, we reached the following conclusions: (a) The adducts inhibit Escherichia coli's gyrase showing that the dissociation of the compounds is not necessary for their activity. However, the presence of the pyoverdin moiety on the molecule decreases the inhibition activity compared to the antibiotic alone. (b) They facilitate the uptake of (55)Fe using the specific pyoverdin-mediated iron-transport system of the bacterium. No uptake was observed either with P. aeruginosa ATCC 27853, which produces a structurally different pyoverdin, or with P. aeruginosa K690, which is a mutant of P. aeruginosa ATCC 15692 lacking FpvA, the outer-membrane pyoverdin receptor. (c) MIC determinations have shown that only strains P. aeruginosa ATCC 15692 and the derived outer-membrane receptor-producing but pyoverdin-deficient P. aeruginosa IA1 mutant present higher susceptibility to the pyoverdin-quinolone adducts, whereas P. aeruginosa ATCC 27853 and K690 are much more resistant. (d) Growth inhibition by these adducts confirmed these results and showed that the adducts with the hydrolyzable spacer arm have better activity than those with the stable one and that the labile spacer arm adducts present much higher activity than the quinolones alone. These results show clearly that the penetration of the antibiotic into the cells is favored when this latter is coupled with pyoverdin: Only the strains possessing the appropriate outer-membrane receptor present higher susceptibility to the adduct. In this case the antibiotic uses the pyoverdin-mediated iron-transport system. Furthermore, better efficiency is obtained when the spacer arm is labile and favors the antibiotic release inside the cell, allowing better inhibition of gyrase.

Overexpression, purification and photoaffinity labeling with a 3H-analogue of norfloxacin, of the GyrA and GyrB subunits of the DNA gyrase.

In spite of much work on DNA gyrase and quinolones for many years, our knowledge of the molecular basis of quinolone-gyrase action is still incomplete. We designed a photoaffinity labeling reagent for the quinolone target, and synthesized a norfloxacin analogue with an azide function which, under UV irradiation, becomes covalently linked to its target. For that, a large amount of purified gyrase was needed. Both subunits were purified using exclusion and affinity chromatography. A plasmid was used that allowed the overproduction of GyrA as a fusion-protein with six histidine residues at its carboxy-terminal domain. GyrA-(His)6 was purified after chromatography on a nickel-containing column, and native GyrB after chromatography on immobilized novobiocin. Reconstituted DNA gyrase (A2B2) had supercoiling activity. Photoaffinity labeling showed covalent binding of the 3H-photoaffinity analogue of norfloxacin to the gyrase-DNA complex, and mainly to the GyrA. The specific binding site remains to be explored.

Cell-cycle-dependent nuclear translocation of HSP70 in amphibian embryonic cells.

Using immunocytochemical methods, we analyzed the localization of the HSP70 protein constitutively expressed during embryogenesis in the amphibian Pleurodeles waltl. Our results provide evidence for nuclear transfer of the protein during gastrulation, and particularly for predominant nuclear labeling in gastrula internalized cells. Using two inhibitors of DNA replication -hydroxyurea (HUA) and aphidicolin- or/and an inhibitor of transcription -actinomycin D- applied to embryos, we demonstrated that nuclear transfer of HSP70 is related to the transcriptional activity of the cells during the early S phase of the cell cycle.

Evidence for specific RNA/protein interactions in the differential segment of the W sex chromosome in the amphibian Pleurodeles waltl.

Pleurodeles exhibits a ZZ/ZW system of GSD (genotype sex determination). However, the Z and W sex chromosomes appear to be morphologically identical. A short RNA sequence is described that was specifically bound to lampbrush loops in the differential segment of the sexual bivalent IV. The distribution of these labeled loops in experimentally produced ZZ and WW females enabled us to demonstrate that such labeled loops were perfectly correlated with the W chromosome. Therefore, this RNA sequence constitutes an excellent marker for the W differential segment. Furthermore, analysis of the labeled loops under various experimental conditions suggested that their labeling is caused by specific interactions between this RNA sequence and lampbrush loop-associated proteins (RNA/protein interactions). North-western assays revealed that nuclear polypeptide(s) of 65 kDa could be responsible for such binding.