A systematic typology for negative Poisson's ratio materials and the prediction of complete auxeticity in pure silica zeolite JST.

Single crystals can commonly have negative Poisson's ratio in a few directions; however more generalised auxeticity is rarer. We propose a typology to distinguish auxetic materials. We characterise numerous single crystals and demonstrate that partial auxeticity occurs for around 37%. We find average auxeticity to be limited to α-cristobalite and no example of complete auxeticity. We simulate two hundreds pure silica zeolites with empirical potentials and quantum chemistry methods, and for the first time identify complete auxeticity in a zeolite network, JST.

Free energy landscapes for the thermodynamic understanding of adsorption-induced deformations and structural transitions in porous materials.

Soft porous crystals are flexible metal-organic frameworks that respond to physical stimuli such as temperature, pressure, and gas adsorption by large changes in their structure and unit cell volume. While they have attracted a lot of interest, molecular simulation methods that directly couple adsorption and large structural deformations in an efficient manner are still lacking. We propose here a new Monte Carlo simulation method based on non-Boltzmann sampling in (guest loading, volume) space using the Wang-Landau algorithm, and show that it can be used to fully characterize the adsorption properties and the material's response to adsorption at thermodynamic equilibrium. We showcase this new method on a simple model of the MIL-53 family of breathing materials, demonstrating its potential and contrasting it with the pitfalls of direct, Boltzmann simulations. We furthermore propose an explanation for the hysteretic nature of adsorption in terms of free energy barriers between the two metastable host phases.

Identification of a Grotthuss proton hopping mechanism at protonated polyhedral oligomeric silsesquioxane (POSS) - water interface.

The attachment and dissociation of a proton from a water molecule and the proton transfers at solid-liquid interfaces play vital roles in numerous biological, chemical processes and for the development of sustainable functional materials for energy harvesting and conversion applications. Using first-principles computational methodologies, we investigated the protonated forms of polyhedral oligomeric silsesquioxane (POSS-H+) interacting with water clusters (Wn, where n = 1-6) as a model to quantify the proton conducting and localization ability at solid-liquid interfaces. Successive addition of explicit water molecules to POSS-H+ shows that the assistance of at least three water molecules is required to dissociate the proton from POSS with the formation of an Eigen cation (H9O4+), whereas the presence of a fourth water molecule highly favors the formation of a Zundel ion (H5O2+). Reaction pathway and energy barrier analysis reveal that the formation of the Eigen cation requires significantly higher energy than the Zundel features. This confirms that the Zundel ion is destabilized and promptly converts in to Eigen ion at this interface. Moreover, we identified a Grotthuss-type mechanism for the proton transfer through a water chain close to the interface, where symmetrical and unsymmetrical arrangements of water molecules around H+ of protonated POSS-H+ are involved in the conduction of proton through water wires where successive Eigen-to-Zundel and Zundel-to-Eigen transformations are observed in quick succession.

Virus replication and cell modifications in organ cultures of tumor tissue from chickens with Marek's disease.

Organ cultures of lymphomas from chickens infected with Marek's disease (MD) virus were examined by electron microscopy at various periods after explantation. Non-enveloped herpes-type virions were observed in explants 18 days after the culture was initiated. Cytolytic virus was replicated often in lymphoblastoid cells and occasionally in other cell types (permissive and nonpermissive transformed). The permissive cells were numerous, but nonpermissive transformed cells were also present as indicated by the longevity of some cultures. The presence of both permissive and transformed cell types in the organ cultures and reasons for their sequential appearance were discussed. The results unequivocally demonstrated that lymphoid cells of tumors induced by MD virus were sites of virus replication under proper culture conditions.

Defects in metal-organic frameworks: a compromise between adsorption and stability?

Defect engineering has arisen as a promising approach to tune and optimise the adsorptive performance of metal-organic frameworks. However, the balance between enhanced adsorption and structural stability remains an open question. Here both CO2 adsorption capacity and mechanical stability are calculated for the zirconium-based UiO-66, which is subject to systematic variations of defect scenarios. Modulator-dependence, defect concentration and heterogeneity are explored in isolation. Mechanical stability is shown to be compromised at high pressures where uptake is enhanced with an increase in defect concentration. Nonetheless this reduction in stability is minimised for reo type defects and defects with trifluoroacetate substitution. Finally, heterogeneity and auxeticity may also play a role in overcoming the compromise between adsorption and stability.

French Otorhinolaryngology Society guidelines for day-case nasal surgery.

OBJECTIVES: The French Otorhinolaryngology Society (SFORL) set up a work group to draw up a consensus document on day-case surgery in four rhinologic procedures: endoscopic middle meatal antrostomy (French National Health Insurance (CCAM) code GBPE001), septoplasty (GAMA007), and reduction of nasal bone fracture using a direct approach (LAEA007) and using a closed technique (LAEP002). MATERIALS AND METHODS: Methodology followed the French Health Authority (HAS) "Methodological Bases for Drawing Up Professional Guidelines by Formalized Consensus" published in January 2006; the method chosen was the short version of the RAND/UCLA Appropriateness Method (without editorial group), as the work group topic was highly specialized, with few experts available. RESULTS: Ahead of any day-case sinonasal surgery, it is recommended that patient eligibility criteria be respected and hemorrhagic risk assessed; preference should be given to short procedures involving little variation in surgery time and minimizing blood-loss, and associated procedures (e.g., septoplasty+turbinectomy) should be avoided. The patient and family should be informed of specific hemorrhagic, orbital and/or neuromeningeal risks, onset of which may preclude discharge home. Uni- or bilateral postoperative nasal packing is not a contraindication to day-case management. CONCLUSION: All four procedures may be performed on a day-case basis. Eligibility criteria should be systematically respected, but hemorrhagic risk, which is very specific to the sinonasal organ, is to be assessed on a case-by-case basis, as it is a major issue in this kind of management for a non-negligible number of patients.

Effect of Cryptosporidium baileyi in specific pathogen free chickens vaccinated (CVI988/Rispens) and challenged with HPRS-16 strain of Marek's.

This study was performed to examine the effect of Marek's disease virus (MDV) serotype 1 vaccine (CVI988/Rispens) on the pathogenicity of Cryptosporidium baileyi , and to determine whether C. baileyi infection could prevent the development of vaccinal Marek's disease (MD) immunity in specific pathogen free (SPF) chickens. Sixty-eight SPF homozygous B13 White Leghorn chickens were divided into seven groups. C. baileyi was orally administered at 5 days of age (day 4) in chickens infected with Rispens vaccine at day 0 or at day 8 and challenged with HPRS-16 strain of oncogenic MDV at day 15. Relevant control groups were constituted. The chickens were kept in isolators until the end of the experiment at day 62. The parameters evaluated were clinical signs, kinetics of oocyst shedding, mortality, macroscopic and microscopic lesions, cryptosporidia location in various organs and serum anti- C. baileyi antibodies at days 42 and 62. Our results show that C. baileyi , which is considered to be non-pathogenic when inoculated orally, may become highly pathogenic. It induced severe mortality and developed in organs other than classical target sites when chickens were vaccinated with Rispens vaccine and challenged with the HPRS-16 strain of MDV.However,parasite infection does not prevent the induction of vaccinal immunity for MD. Our results also show that vaccination of B13 chickens at hatching induces higher protection against challenge with HPRS-16 MDV at day 15 than vaccination at day 8.

Pathogenicity of a Marek's disease virus for chickens vaccinated with graded doses of herpesvirus of turkeys.

Six different groups of one-day-old chickens were vaccinated with herpesvirus of turkeys (HVT) vaccine at doses of 0, 4, 16, 64, 256 and 1,024 plaqueforming units. At 9 days of age they were challenged with an acute strain of Marek's disease herpesvirus (MDHV). Gross and microscopic lesions in nerves and gonads were investigated and combined for quantitative expression of MDHV pathogenicity. Including the microscopic lesions improved the accuracy of the HVT doses/MDHV response. The qualitative aspects of late microscopic lesions could be related to acquired resistance or to persistence of susceptibility in vaccinated chickens.

Protein concentrations and immunosuppressive properties of serum in chickens experimentally infected with avian tumor viruses.

Sera from chickens affected by Marek's disease or developing Rous sarcoma were investigated. There were changes in the protein fractions, and the amount of alpha and beta fractions was consistently increased. At the same time, immunosuppressive factors were found to inhibit the number of plaque-forming cells in the spleen of mice immunized with sheep red blood cells.

Analysis of B complex polymorphism in Rous sarcoma progressor and regressor chickens with B-G, B-F, and B-L beta probes.

Molecular polymorphism of the B complex was studied in serologically defined B19 haplotypes by use of class I, class II, and class IV probes in Southern blot experiments in chickens. All chickens studied shared identical class IV restriction patterns. In contrast, class I and class II probes revealed six and five subtypes of B19 haplotype, respectively. These subtypes may be resolved in three homozygous genotypes and their corresponding heterozygous combinations. Previous genetic selection allowed us to distinguish two subpopulations in these B19 chickens with regard to the fate of Rous sarcoma virus (RSV)-induced tumors. Molecular genotyping was applied to B19 chickens challenged with RSV in order to determine whether there is a correlation between one of the molecularly defined subtypes and the progressor/regressor phenotypes of the chickens. None of the molecularly defined subtypes correlated with the progressor or regressor phenotype of the challenged birds.

Interaction of Marek's disease virus and Cryptosporidium baileyi in experimentally infected chickens.

Histocompatible B13/B13 white specific-pathogen-free leghorn chickens were used to investigate the effect of coinfection with Cryptosporidium baileyi and the HPRS 16 strain of Marek's disease virus (MDV) in chickens and to assess the pathogenicity of C. baileyi when MDV is given before or after the parasite. Groups of chickens concurrently infected with C. baileyi orally inoculated at day (D)4 and MDV inoculated at hatching (C4M0 group) or at D8 (C4M8 group) were compared with relevant control groups inoculated with only C. baileyi at D4 (C4 group), only MDV at hatching (M0 group) or at D8 (M8 group), and an uninoculated control group (UC group). The chickens were kept in isolator units until the end of the experiment at D62. Our results showed a considerable synergistic effect in concurrently infected chickens and more severe consequences when chickens received MDV before C. baileyi infection. In fact, except for a slight transitory weakness, the chickens in C4 group remained free of overt clinical signs and there was no mortality. However, coinfection with both pathogens induced more lasting or permanent oocyst shedding. Severe clinical cryptosporidiosis with weakness, anorexia, depression, growth retardation, and chronic and severe respiratory disease causing death occurred in all chickens in the C4M0 group between D12 and D43 and in 67% of the chickens in the C4M8 group between D17 and D57. Eighty-two percent and 33%, respectively, died before the development of specific Marek's disease lesions. Mortality rates were 27% and 33% in the M0 and M8 groups, respectively. The presence of MDV enhanced the establishment of more lasting cryptosporidial infection in the respiratory tract, esophagus, crop, proventriculus, and kidneys (only in C4M0 group) as well as in bursa of Fabricius, ceca, and cloaca. Serologic analysis showed that chickens with chronic cryptosporidiosis in the C4M8 group had an increased level of C. baileyi-specific immunoglobulin A. Our results may explain some cases of mortality in chickens naturally infected with MDV and Cryptosporidium.

Renal Cryptosporidiosis (Cryptosporidium baileyi) in specific-pathogen-free chickens experimentally coinfected with Marek's disease virus.

Renal Cryptosporidiosis was experimentally induced during a study to investigate the pathogenicity of Cryptosporidium baileyi in specific-pathogen-free (SPF) chickens coinfected with Marek's disease virus (MDV). Cryptosporidium baileyi was administered orally at 4 days of age to chickens previously infected at hatching (day 0) with the HPRS 16 strain of oncogenic MDV. Three control groups received MDV at hatching, C. baileyi on day 4, or placebo consisting of distilled water. Renal cryptosporidiosis lesions were induced in the group coinfected with MDV and C. baileyi. The kidneys were markedly swollen and pale, with visible urate crystals in the ureters and surface tubules. Oocysts of C. baileyi were demonstrated in six of seven cases tested by a scoring method with modified Sheather's sugar solution on renal tissue scrapings and were confirmed in three cases by histologic examination of paraffin-embedded kidney sections. Histologic study also revealed subacute interstitial nephritis, acute ureteritis, and attachment of cryptosporidia on the epithelial cell surface of the ureters and collecting ducts, collecting tubules, and distal convoluted tubules. Various developmental stages of the parasite were present in the kidney sections. To our knowledge, this is the first report of experimentally induced renal cryptosporidiosis in SPF chickens coinfected with MDV.

Intratesticular inoculation of avian leukosis virus (ALV) in chickens--production of neutralizing antibodies and lack of virus shedding into semen.

In order to investigate the possibility of producing transgenic chickens by injection of avian leukosis virus-based vectors into testis, we have analyzed the infection rate of testicular cells following inoculation of Rous-associated virus type 1 (RAV-1) into the gonads of adult and 1-wk-old brown leghorn males. Viroproduction, neutralizing antibody production, and vital DNA presence in testis, blood, muscle, and semen were analyzed at various times after infection. Inoculation of RAV-1 into the gonads of adult males resulted in a low level of viroproduction in testis and blood, followed by the appearance of neutralizing antibody 2 or 3 wk later. Neither viroproduction in semen nor viral DNA presence in sperm were detected even though the infected chickens were found to produce RAV-1 in testis. One week after intratesticular inoculation of 1-wk-old males with RAV-1, a high level of viroproduction was found in blood and testis, and viral DNA was detected in gonadal cells. Further, by 6 wk after inoculation, the production of virus decreased in all tissues, viral DNA could not longer be detected in the testis, and neutralizing antibodies appeared in blood. All together these data show that it is possible to infect testicular cells by direct inoculation of RAV-1 in the testis, and that the immune response of both adult and young chickens seems to reduce this infection. Moreover, no evidence of spermatozoa infection was found; this result suggests that RAV-1 inoculation into testis may not induce genetic transmission of virus, and consequently would not be useful in the production of transgenic chickens.

[Influence of B locus on avian viral induced tumours]. / Influence du locus B sur les tumeurs virales aviaires.

Since early in the century Avian Cancers were described as induced by viruses which later were known of DNA and RNA types. The susceptibility of birds was found different according to the genetic lines of the chickens and specially to the B locus blood group. Since the B locus of birds was strongly associated with the Major Histocompatibility Complex (MHC) it was of interest to review the last reports on the influence of the B locus on viral induced tumours. In Marek's Disease due to a DNA virus (Herpes type) the B21 allele expresses the greater resistance compared with other B alleles although non-B factors could be involved as demonstrated with the lymphocyte factor Ly-4. The possible mechanisms of the influence of B locus on the resistance against Marek's Disease are discussed. The tumours induced by RNA viruses (Avian Leucosis Sarcomas) develop or regress following genetic characters closely related to MHC. Differences of resistance exist between B alleles. Complementary genes should be present to fully express the resistance. The relationship between MHC-B locus and resistance to tumors stimulates the actual assays. Since a number of parameters remain still unknown further researches should be done in order to evidence the involved mechanisms of the resistance.

Chicken thymocyte-specific antigens identified by monoclonal antibodies: characterization and distribution in normal tissues and in tumoral tissues from Marek's disease chicken.

Monoclonal antibodies (MAbs) were obtained against purified thymocyte membrane extracts. Five MAbs TA3, TB1, TB6 (IgG1), TC4, and TA1 (IgG2a), were tested by immunofluorescence and by immunoperoxidase tests against normal cells from different organs, Marek's disease (MD) cell lines, and MD tumoral cells from chickens. Three of them, TA3, TB1, and TB6, reacted exclusively with lymphoid cells in both cortical and medullary areas of the thymus and with less than 8% bursa cells. They identified a protein of apparently 40 kD. The other two revealed antigenic determinants on most medullar thymocytes and some cortical thymocytes, and on some splenic and peripheral blood lymphocytes. They were positive with MD cell lines and cells deriving from MD tumors. TC4 and TA1 detected molecular masses of about 110 kD and 16 kD, respectively. No MAbs reacted with erythrocytes, bone marrow, liver, brain, and skin cells. Not all of the tested cells were stained after contact with an anti-chicken immunoglobulin serum. In this paper, we determine a specific antigen restricted to T cells from thymus and different markers belonging to the mature T cells. The latter are also present on MD cell lines and MD tumoral cells.

The purification of lymphocytes in chicken blood.

Several methods have been tried in attempts to purify the lymphocytes of chicken blood. The most efficient one is based upon the properties of adhesion of the polymorphonuclears and monocytes. With the use of a column filled with synthetic fibers, held at 37 degrees C., a high rate of lymphocyte purification was obtained. Sedimentation and centrifugation then resulted in the elimination of almost all of the erythrocytes. The final product was homogeneous and the lymphocytes obtained kept the physiological and metabolic properties necessary for their culture.

Somatic and germline chicken chimeras obtained from brown and white Leghorns by transfer of early blastodermal cells.

Stage X blastodermal cells were isolated from freshly laid unincubated Brown Leghorn chicken eggs. Five hundred cells from Stage X Brown Leghorn embryos were injected into the subgerminal cavity of White Leghorn unincubated embryos exposed to 550 rad of gamma irradiation from a cesium-137 source. Of 712 White Leghorn embryos that were irradiated and injected with Brown Leghorn blastodermal cells, 52 (7.3%) survived to hatching. Somatic chimerism was examined in the melanocyte population and erythroid lineage. The presence of brown feathers indicating donor cell contribution to melanocyte pigmentation was observed in 23 (44%) out of the 52 hatched chicks. Analysis of blood DNA was performed using a probe that revealed an endogenous retroviral gag fragment specific for the donor genome. Three out of these 23 chimeric chickens exhibited the gag-specific fragment. To test germline chimerism, chickens that reached sexual maturity were mated with Brown Leghorns. Three somatically chimeric hens produced Brown Leghorn progeny at a rate of 30.7, 9.2, and 2.9% respectively, thus proving donor cell contribution to the germline differentiation. Chimeric chickens obtained after injection of nonirradiated embryos exhibited a lower extent of chimerism at the feather level and did not show any chimerism in the erythroid lineage and the germline, thus demonstrating the value of the use of compromised recipient embryos to produce chimeras in chickens. Nevertheless, the extent of somatic chimerism could not be used to predict the germline chimerism.

Antigen requirements and specificity of a microplate enzyme-lined immunosorbent assay (ELISA) for Marek's disease viral antibodies in chicken, mouse and rabbit sera.

A rapid indirect enzyme linked immunosorbent assay for the detection of antibodies against Marek's disease virus in mouse, chicken and rabbit-sera has been established. Optimal sensitivity was obtained by using 10 micrograms/ml of partially purified viral proteins. Various experimental procedures performed to eliminate nonspecific reactions are described. Best results were obtained by the introduction of NP 40 at a concentration of 0.1% in sera. With mouse sera, the pretreatment of plaques with poly-L-lysine before antigen fixation substantially reduced the occurrence of nonspecific reactions.