ICTV Virus Taxonomy Profile: Iflaviridae.

Iflaviridae is a family of small non-enveloped viruses with monopartite, positive-stranded RNA genomes of approximately 9-11 kilobases. Viruses of all classified species infect arthropod hosts, with the majority infecting insects. Both beneficial and pest insects serve as hosts, and infections can be symptomless (Nilaparvatalugens honeydew virus 1) or cause developmental abnormalities (deformed wing virus), behavioural changes (sacbrood virus) and premature mortality (infectious flacherie virus). The host range has not been examined for most members. The most common route of infection for iflaviruses is the ingestion of virus-contaminated food sources. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Iflaviridae, which is available at www.ictv.global/report/iflaviridae.

ICTV Virus Taxonomy Profile: Dicistroviridae.

Dicistroviridae is a family of small non-enveloped viruses with monopartite, linear, positive-sense RNA genomes of approximately 8-10 kb. Viruses of all classified species infect arthropod hosts, with some having devastating economic consequences, such as acute bee paralysis virus in domesticated honeybees and taura syndrome virus in shrimp farming. Conversely, the host specificity and other desirable traits exhibited by several members of this group make them potential natural enemies for intentional use against arthropod pests, such as triatoma virus against triatomine bugs that vector Chagas disease. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Dicistroviridae which is available at www.ictv.global/report/dicistroviridae.

The influence of fibril composition and dimension on the performance of paper gated oxide transistors.

Paper electronics is a topic of great interest due the possibility of having low-cost, disposable and recyclable electronic devices. The final goal is to make paper itself an active part of such devices. In this work we present new approaches in the selection of tailored paper, aiming to use it simultaneously as substrate and dielectric in oxide based paper field effect transistors (FETs). From the work performed, it was observed that the gate leakage current in paper FETs can be reduced using a dense microfiber/nanofiber cellulose paper as the dielectric. Also, the stability of these devices against changes in relative humidity is improved. On other hand, if the pH of the microfiber/nanofiber cellulose pulp is modified by the addition of HCl, the saturation mobility of the devices increases up to 16 cm(2) V(-1) s(-1), with an ION/IOFF ratio close to 10(5).

Water electrolysis and energy harvesting with zero-dimensional ion-sensitive field-effect transistors.

The relationship of the gas bubble size to the size distribution critically influences the effectiveness of electrochemical processes. Several optical and acoustical techniques have been used to characterize the size and emission frequency of bubbles. Here, we used zero-dimensional (0D) ion-sensitive field-effect transistors (ISFETs) buried under a microbath to detect the emission of individual bubbles electrically and to generate statistics on the bubble emission time. The bubble size was evaluated via a simple model of the electrolytic current. We suggest that energy lost during water electrolysis could be used to generate electric pulses at an optimal efficiency with an array of 0D ISFETs.

Cryo-electron microscopy reconstructions of triatoma virus particles: a clue to unravel genome delivery and capsid disassembly.

Triatoma virus (TrV) is a member of the insect virus family Dicistroviridae and consists of a small, non-enveloped capsid that encloses its positive-sense ssRNA genome. Using cryo-transmission electron microscopy and three-dimensional reconstruction techniques combined with fitting of the available crystallographic models, this study analysed the capsids corresponding to mature and several RNA-empty TrV particles. After genome release, the resulting reconstruction of the empty capsids displayed no prominent conformational changes with respect to the full virion capsid. The results showed that RNA delivery led to empty capsids with an apparent overall intact protein shell and suggested that, in a subsequent step, empty capsids disassemble into small symmetrical particles. Contrary to what is observed upon genome release in mammalian picornaviruses, the empty TrV capsid maintained a protein shell thickness and size identical to that in full virions.

Dupuytren's disease presentation, referral pathways and resource utilisation in Europe: regional analysis of a surgeon survey and patient chart review.

AIM: We explored the management of Dupuytren's disease (DD) using a surgeon survey and patient chart review. METHODS: Twelve countries participated: Denmark, Finland, Sweden (Nordic region); Czech Republic, Hungary, Poland (East); France, Germany, the Netherlands, United Kingdom (West); Italy, Spain (Mediterranean). A random sample of orthopaedic/plastic surgeons (N = 687) with 3-30 years' experience was asked about Dupuytren's contracture procedures performed during the previous 12 months. Information ≤ 5 consecutive patients per surgeon was extracted from patient charts (N = 3357). RESULTS: Overall, 84% of participants were orthopaedic surgeons; 56% of surgeons were hand specialists. Deciding factors for fasciectomy and dermofasciectomy were consistent across regions: metacarpophalangeal (MP) or proximal interphalangeal contracture > 45°, recurrent contracture, and high expectations for success. Deciding factors for percutaneous needle fasciotomy were less consistent across regions, but the leading factor was MP flexion < 20°. Overall, 49% of diagnoses and 55% of referrals were made by a general practitioner (GP), with regional variation: 31-77% for GP diagnoses and 36-81% for GP referrals. There were also differences in admission status (e.g. 9% of Nordic patients and 80% of Eastern patients were treated as inpatients). Most patients were treated in public hospitals and most procedures were covered by public health insurance. CONCLUSIONS: We found regional variations in surgical practice, patient characteristics and referral patterns. Understanding current diagnosis and treatment patterns, in relation to regional differences in health economics, may improve physicians' diagnosis of DD and guide patients towards appropriate, customised management plans.

Surgical management of Dupuytren's contracture in Europe: regional analysis of a surgeon survey and patient chart review.

AIM: We explored regional variations in the surgical management of patients with Dupuytren's contracture (DC) in 12 European countries using a surgeon survey and patient chart review. METHODS: Twelve countries participated: Denmark, Finland, Sweden (Nordic region); Czech Republic, Hungary, Poland (East); France, Germany, the Netherlands, UK (West); Italy, Spain (Mediterranean). For the survey, a random sample of orthopaedic/plastic surgeons (n = 687) with 3-30 years' experience was asked about DC procedures performed during the previous 12 months. For the chart review (n = 3357), information from up to five consecutive patients was extracted. Descriptive statistics are reported. RESULTS: Ninety-five per cent of all surgeons used fasciectomy for DC, followed by fasciotomy (70%), dermofasciectomy (38%) and percutaneous needle fasciotomy (35%). Most surgeons were satisfied with fasciectomy over other procedures. Recommended time away from work and duration of physical therapy increased with the invasiveness of the procedure. The intra-operative complication rate was 4.0%; the postoperative complication rate was 34%. Overall, ≥ 97% of the procedures were rated by surgeons as having a positive outcome. Across all regions, 54% of patients had no nodules or contracture after the procedures. Only 2% of patients required retreatment within the first year of surgery. Important inter- and intraregional differences in these aspects of patient management are described. CONCLUSIONS: Understanding current regional treatment patterns and their relationships to country-specific health systems may facilitate earlier identification of, and intervention for, DD and help to optimise the overall treatment for patients with this chronic condition.

Conductance switching at the nanoscale of diarylethene derivative self-assembled monolayers on La0.7Sr0.3MnO3.

We report on the phosphonic acid route for the grafting of functional molecules, optical switch (dithienylethene diphosphonic acid, DDA), on La0.7Sr0.3MnO3 (LSMO). Compact self-assembled monolayers (SAMs) of DDA are formed on LSMO as studied by topographic atomic force microscopy (AFM), ellipsometry, water contact angle measurements and X-ray photoemission spectroscopy (XPS). The conducting AFM measurements show that the electrical conductance of LSMO/DDA is about 3 decades below that of a bare LSMO substrate. Moreover, the presence of the DDA SAM suppresses the known conductance switching of the LSMO substrate that is induced by mechanical and/or bias constraints during C-AFM measurements. A partial light-induced conductance switching between the open and closed forms of the DDA is observed for the LSMO/DDA/C-AFM tip molecular junctions (closed/open conductance ratio of about 8). We show that, in the case of long-time exposure to UV light, this feature can be masked by a non-reversible decrease (a factor of about 15) of the conductance of the LSMO electrode.

Electrical molecular switch addressed by chemical stimuli.

We demonstrate that the conductance switching of benzo-bis(imidazole) molecules upon protonation depends on the lateral functional groups. The protonated H-substituted molecule shows a higher conductance than the neutral one (Gpro > Gneu), while the opposite (Gneu > Gpro) is observed for a molecule laterally functionalized by amino-phenyl groups. These results are demonstrated at various scale lengths: self-assembled monolayers, tiny nanodot-molecule junctions and single molecules. From ab initio theoretical calculations, we conclude that for the H-substituted molecule, the result Gpro > Gneu is correctly explained by a reduction of the LUMO-HOMO gap, while for the amino-phenyl functionnalized molecule, the result Gneu > Gpro is consistent with a shift of the HOMO, which reduces the density of states at the Fermi energy.

Crystallization and preliminary crystallographic analysis of fragaceatoxin C, a pore-forming toxin from the sea anemone Actinia fragacea.

Sea anemones produce water-soluble toxins that have the ability to interact with cell membranes and form pores within them. The mechanism of pore formation is based on an initial binding step followed by oligomerization and membrane insertion. Although the final structure of the pore remains unclear, biochemical studies indicate that it consists of a tetramer with a functional radius of approximately 1.1 nm. Since four monomers seem to be insufficient to build a pore of this size, the currently accepted model suggests that lipids might also participate in its structure. In this work, the crystallization and preliminary crystallographic analysis of two crystal forms of fragaceatoxin C (FraC), a newly characterized actinoporin from Actinia fragacea, are described. The crystals diffracted up to 1.8 A resolution and the preliminary molecular-replacement solution supports an oligomeric structure of about 120 A in diameter.

Charge transport through redox active [H7P8W48O184]33- polyoxometalates self-assembled onto gold surfaces and gold nanodots.

Polyoxometalates (POMs) are redox-active molecular oxides, which attract growing interest for their integration into nano-devices, such as high-density data storage non-volatile memories. In this work, we investigated the electrostatic deposition of the negatively charged [H7P8W48O184]33- POM onto positively charged 8-amino-1-octanethiol self-assembled monolayers (SAMs) preformed onto gold substrates or onto an array of gold nanodots. The ring-shaped [H7P8W48O184]33- POM was selected as an example of large POMs with high charge storage capacity. To avoid the formation of POM aggregates onto the substrates, which would introduce variability in the local electrical properties, special attention has to be paid to the preformed SAM seeding layer, which should itself be deprived of aggregates. Where necessary, rinsing steps were found to be crucial to eliminate these aggregates and to provide uniformly covered substrates for subsequent POM deposition and electrical characterizations. This especially holds for commercially available gold/glass substrates while these rinsing steps were not essential in the case of template stripped gold of very low roughness. Charge transport through the related molecular junctions and nanodot molecule junctions (NMJs) has been probed by conducting-AFM. We analyzed the current-voltage curves with different models: electron tunneling though the SAMs (Simmons model), transition voltage spectroscopy (TVS) method or molecular single energy level mediated transport (Landauer equation) and we discussed the energetics of the molecular junctions. We concluded to an energy level alignment of the alkyl spacer and POM lowest occupied molecular orbitals (LUMOs), probably due to dipolar effects.

Physical mechanisms involved in the formation and operation of memory devices based on a monolayer of gold nanoparticle-polythiophene hybrid materials.

Understanding the physical and chemical mechanisms occurring during the forming process and operation of an organic resistive memory device is a requisite for better performance. Various mechanisms were suggested in vertically stacked memory structures, but the analysis remains indirect and needs destructive characterization (e.g. analysis of the cross-section to access the organic layers sandwiched between electrodes). Here, we report a study on a planar, monolayer thick, hybrid nanoparticle/molecule device (10 nm gold nanoparticles embedded in an electro-generated poly(2-thienyl-3,4-(ethylenedioxy)thiophene) layer), combining in situ physical (scanning electron microscopy, physicochemical thermogravimetry and mass spectroscopy, and Raman spectroscopy) and electrical (temperature dependent current-voltage) characterization on the same device. We demonstrate that the forming process causes an increase in the gold particle size, almost 4 times larger than the starting nanoparticles, and that the organic layer undergoes a significant chemical rearrangement from an sp3 to sp2 amorphous carbon material. Temperature dependent electrical characterization of this nonvolatile memory confirms that the charge transport mechanism in the device is consistent with a trap-filled space charge limited current in the off state, with the sp2 amorphous carbon material containing many electrically active defects.

Electron transport through rectifying self-assembled monolayer diodes on silicon: Fermi-level pinning at the molecule-metal interface.

We report the synthesis and characterization of molecular rectifying diodes on silicon using sequential grafting of self-assembled monolayers of alkyl chains bearing a pi group at their outer end (Si/sigma-pi/metal junctions). We investigate the structure-performance relationships of these molecular devices, and we examine the extent to which the nature of the pi end group (change in the energy position of their molecular orbitals) drives the properties of these molecular diodes. Self-assembled monolayers of alkyl chains (different chain lengths from 6 to 15 methylene groups) functionalized by phenyl, anthracene, pyrene, ethylene dioxythiophene, ethylene dioxyphenyl, thiophene, terthiophene, and quaterthiophene were synthesized and characterized by contact angle measurements, ellipsometry, Fourier transform infrared spectroscopy, and atomic force microscopy. We demonstrate that reasonably well-packed monolayers are obtained in all cases. Their electrical properties were assessed by dc current-voltage characteristics and high-frequency (1-MHz) capacitance measurements. For all of the pi groups investigated here, we observed rectification behavior. These results extend our preliminary work using phenyl and thiophene groups (Lenfant et al., Nano Lett. 2003, 3, 741). The experimental current-voltage curves were analyzed with a simple analytical model, from which we extracted the energy position of the molecular orbital of the pi group in resonance with the Fermi energy of the electrodes. We report experimental studies of the band lineup in these silicon/alkyl pi-conjugated molecule/metal junctions. We conclude that Fermi-level pinning at the pi group/metal interface is mainly responsible for the observed absence of a dependence of the rectification effect on the nature of the pi groups, even though the groups examined were selected to have significant variations in their electronic molecular orbitals.

Superficial angiomyxoma: clinicopathologic analysis of a series of distinctive but poorly recognized cutaneous tumors with tendency for recurrence.

Despite being first described in 1988, superficial angiomyxoma is still a poorly recognized cutaneous tumor. Although its histologic features are distinctive, its existence seems not to be widely accepted. We analyzed the clinicopathologic and immunohistochemical features in a series of 39 cases. Twenty-five patients were males; age range was birth to 82 years (median, 45.5 years). Most cases presented as cutaneous papules, nodules, or polypoid lesions. Seventeen tumors arose on the trunk, 14 on the head and neck, and seven on the lower limbs. All cases were treated by local excision, and eight recurred locally. In four of the latter cases, there were two recurrences. Histologically, the lesions were dermal with variable involvement of the subcutis. Tumors were poorly circumscribed, but a focal lobular outline was always identified. Distinctive histologic features included extensive myxoid stroma, numerous small blood vessels, varying cellularity, acellular mucin pools, stellate or bipolar fibroblastic cells, muciphages, a sparse, mixed inflammatory cell infiltrate with notable neutrophils, and occasional plumper cells with eosinophilic cytoplasm. Cytologic atypia was mild at most, and mitotic figures were rare. In approximately 20% of cases, the primary lesion or its recurrence contained epithelial structures, including epidermoid cysts, thin strands of squamous epithelium, and small buds of basaloid cells. Immunohistochemically, tumor cells were negative for S-100 protein, smooth muscle actin, and pan-keratin. We support the concept of superficial angiomyxoma as a distinctive clinicopathologic entity that should be included in the differential diagnosis of other myxoid cutaneous tumors, including dermal nerve sheath myxoma, trichodiscoma and trichofolliculoma, and low-grade myxofibrosarcoma.

Amine-catalyzed addition of azide ion to alpha,beta-unsaturated carbonyl compounds.

[formula: see text] A new protocol for the beta-azidation of alpha,beta-unsaturated carbonyl compounds is described. The method employs tertiary amines as catalysts for azide addition. The azide source is a 1:1 mixture of TMSN3 and AcOH. Tertiary amines, either in solution or bound to a solid support, are efficient catalysts for the reaction.

Facile synthesis of N,N'-ethylenebisthiazolium salts: precursors of dithiadiazafulvalenes

Bis-thiazolium salts, precursors of dithiadiazafulvalene (DTDAF), have been prepared. Electrochemical investigations have been carried out on these salts in order to determine the redox behavior of DTDAF. These bis-thiazolium salts undergo intramolecular coupling, either chemically or electrochemically, to afford N,N'-ethylene-bridged DTDAF.

In-vitro cytotoxic activity of cross-linked protein microcapsules.

Microcapsules (5-100 microns) were prepared through interfacial cross-linking of various proteins (human serum albumin, lysozyme, haemoglobin, casein, pepsin) with glutaraldehyde or terephthaloylchloride. Surprisingly they all showed an inhibitory effect on cultured cells in a concentration range of 100 micrograms ml-1 to 10 mg ml-1. This effect seemed non-specific, reversible and to depend on contact with the cell plasma membrane. The electric charges of microcapsules could be involved in the inhibition phenomenon.

Do you underestimate your students?

To establish a bridge of meaning between old and new knowledge and speed up future perceptual learning, it is necessary to call attention to distinctive features and higher order relations. The prerequisite is identification of existing skills and knowledge and selection of content which will ensure that principles, concepts, and generalizations are taught so transfer of learning will be increased. The clarity with which the instructor presents what is expected will strengthen the relevance of the cues used to arouse a present response that is determined by past learning. The substance of a course is derived by identifying the gap between the student's knowledge base and what the instructor wants her to learn. By providing an opportunity for the student to develop skills early in the program, one can eliminate misconceptions and develop increased discrimination. It also decreases apprehension that previously had been a basis for anxiety, reduces redundancy in content and allows more time for new content; whereas, more time is available for clinical experience as less time is needed in a practice lab. Students are better prepared for the future because they were encouraged to think and react with flexibility, creativity, and spontaneity. To be successful, the idea of relating new concepts to a known body of knowledge for transfer must be positively accepted by the instructor. If the instructor's attitude is negative, the student will react negatively. BE POSITIVE.

[Spiruline as a food supplement in case of infant malnutrition in Burkina-Faso]. / La spiruline comme complément alimentaire dans la malnutrition du nourrisson au Burkina-Faso.

BACKGROUND: Spiruline, a microscopic algae with nutritious quality was put forward as food supplement to fight malnutrition in infant. POPULATION AND METHODS: To assess its effectiveness, a survey was carried out among children with malnutrition whose Z-score was <2 for their age, in the Koudougou province, Burkina-Faso. Within five centers, three groups were defined at randomization: group 1 with usual nutritional rehabilitation program, group 2 as above + 5 g x d(-1) of spiruline, group 3 as above + spiruline + fish. 182 children, aged three months - three years, were originally involved. Six died (3.3%) and 11 hospitalised were excluded; the study was carried out on 165 children and lasted three months. Judging criteria were: length per aged, weight for length group evolution and the corresponding Z-score at 60 et 90 days. RESULTS: At the inclusion, children were aged 14.6 months on average and weighed 6.7 kg (Z-score of -3.2 weight/age) with a length of 71.4 cm (-2.0 Z-score length/age) and weight for length of 0.093 (-2.5 Z-score). 9.4% had oedema. There were no noticeable differences between the three groups as to weight gain, length gain, weight for length gain. CONCLUSION: A 5 g x d(-1) spiruline dose does not bring any benefit over 90 days, compared to traditional renutrition. Furthermore, at the moment, it is costly, and the battle against infant malnutrition cannot be based on one single element, such as a wonder drug, but on a national or local policy based on training, education, economical aid, and nutritional rehabilitation centers and infection treatment.

[Ruptured angular pregnancy in the 16th week. Apropos of a case]. / Grossesse angulaire rompue à la 16e semaine. A propos d'un cas.

Angular pregnancies which result from implantation of the fertilised oocyte in the mucosa of a uterine horn are very rare. They are usually demonstrated by a picture of rupture which is associated with severe abdominal pain, the syndrome of internal haemorrhage, often a state of shock and all occurring usually between the 6th and the 12th week of pregnancy. Although many authors have shown that there is congenital abnormality of the uterus in these cases this does not always happen and the aetiology of "idiopathic angular pregnancies" is ill understood. The treatment is carried out according to the clinical state: endometrial curettage under laparoscopic control, removal of the uterine horn together with the tube on the same side or even hysterectomy.