Metal-Substituted Microporous Aluminophosphates

This chapter aims to present the zeotypes aluminophosphates (AlPOs) as a complementary alternative to zeolites in the isomorphic incorporation of metal ions within all-inorganic microporous frameworks as well as to discuss didactically the catalytic consequences derived from the distinctive features of both frameworks. It does not intend to be a compilation of either all or the most significant publications involving metal-substituted microporous aluminophosphates. Families of AlPOs and zeolites, which include metal ion-substituted variants, are the dominant microporous materials. Both these systems are widely used as catalysts, in particular through aliovalent metal ions substitution. Here, some general description of the synthesis procedures and characterization techniques of the MeAPOs (metal-contained aluminophosphates) is given along with catalytic properties. Next, some illustrative examples of the catalytic possibilities of MeAPOs as catalysts in the transformation of the organic molecules are given. The oxidation of the hardly activated hydrocarbons has probably been the most successful use of AlPOs doped with the divalent transition metal ions Co2+, Mn2+, and Fe2+, whose incorporation in zeolites is disfavoured. The catalytic role of these MeAPOs is rationalized based on the knowledge acquired from a combination of the most advanced characterization techniques. Finally, the importance of the high specificity of the structure-directing agents employed in the preparation of MeAPOs is discussed taking N,N-methyldicyclohexylamine in the synthesis of AFI-structured materials as a driving force. It is shown how such a high specificity could be predicted and how it can open great possibilities in the control of parameters as critical in catalysis as crystal size, inter-and intracrystalline mesoporosity, acidity, redox properties, incorporation of a great variety of heteroatom ions or final environment of the metal site (surrounding it by either P or Al)

Cervical epidural steroid injections in the management of cervical radiculitis: interlaminar versus transforaminal. A review

There has been recent concern regarding the safety of cervical epidural steroid injections. The decision to proceed with treatment requires balancing the risk and benefits. This article is an in depth review of the efficacy, complications, and technique of both interlaminar and transforaminal cervical epidural steroid injections in the management of cervical radiculitis

Titanium silicalite-1 macrostructures for photocatalytic removal of organic pollutants from aqueous media

Titanium silicalite-1 (TS-1) structures in the form of macroscopic beads with hierarchical porosity were prepared by the resin templating method. The Ti content within the samples was varied between 1 and 7 wt%, with corresponding surface areas ranging from 725 to 350 m2 g−1, respectively. The samples contained a large amount of amorphous material, which was necessary to achieve high mechanical stability of the beads. The TS-1 macrostructures were used as catalysts for the photocatalytic degradation of methylene blue (MB), and results were compared to the results for a commercial anatase nanopowder (CristalACTiV™ PC500). All TS-1 beads showed similar MB degradation rates independently of their Ti content, which was linked to variations in the surface areas and structure. The macroscopic shape of the TS-1 beads allowed easy recovery from the mother liquor upon decolouration of the MB solutions, which was highly beneficial compared to the reference anatase nanopowder. The TS-1 beads could be reused in subsequent photocatalytic cycles after decanting exhausted solutions and replacing with fresh MB solutions without any energy-consuming regeneration steps involved. The samples were tested in five consecutive cycles and MB degradation rates remained broadly unchanged during all tests

A systematic review of mental disorder, suicide, and deliberate self harm in lesbian, gay and bisexual people

Background: Lesbian, gay and bisexual (LGB) people may be at higher risk of mental disorders than heterosexual people.Method: We conducted a systematic review and meta-analysis of the prevalence of mental disorder, substance misuse, suicide, suicidal ideation and deliberate self harm in LGB people. We searched Medline, Embase, PsycInfo, Cinahl, the Cochrane Library Database, the Web of Knowledge, the Applied Social Sciences Index and Abstracts, the International Bibliography of the Social Sciences, Sociological Abstracts, the Campbell Collaboration and grey literature databases for articles published January 1966 to April 2005. We also used Google and Google Scholar and contacted authors where necessary. We searched all terms related to homosexual, lesbian and bisexual people and all terms related to mental disorders, suicide, and deliberate self harm. We included papers on population based studies which contained concurrent heterosexual comparison groups and valid definition of sexual orientation and mental health outcomes.Results: Of 13706 papers identified, 476 were initially selected and 28 (25 studies) met inclusion criteria. Only one study met all our four quality criteria and seven met three of these criteria. Data was extracted on 214,344 heterosexual and 11,971 non heterosexual people. Meta-analyses revealed a two fold excess in suicide attempts in lesbian, gay and bisexual people [ pooled risk ratio for lifetime risk 2.47 (CI 1.87, 3.28)]. The risk for depression and anxiety disorders (over a period of 12 months or a lifetime) on meta-analyses were at least 1.5 times higher in lesbian, gay and bisexual people (RR range 1.54-2.58) and alcohol and other substance dependence over 12 months was also 1.5 times higher (RR range 1.51-4.00). Results were similar in both sexes but meta analyses revealed that lesbian and bisexual women were particularly at risk of substance dependence (alcohol 12 months: RR 4.00, CI 2.85, 5.61; drug dependence: RR 3.50, CI 1.87, 6.53; any substance use disorder RR 3.42, CI 1.97-5.92), while lifetime prevalence of suicide attempt was especially high in gay and bisexual men (RR 4.28, CI 2.32, 7.88).Conclusion: LGB people are at higher risk of mental disorder, suicidal ideation, substance misuse, and deliberate self harm than heterosexual people

Observed temperature changes in the troposphere and stratosphere from 1979 to 2018

Temperature observations of the upper-air atmosphere are now available for more than 40 years from both ground- and satellite-based observing systems. Recent years have seen substantial improvements in reducing long-standing discrepancies among datasets through major reprocessing efforts. The advent of radio occultation (RO) observations in 2001 has led to further improvements in vertically resolved temperature measurements, enabling a detailed analysis of upper-troposphere/lower-stratosphere trends. This paper presents the current state of atmospheric temperature trends from the latest available observational records. We analyze observations from merged operational satellite measurements, radiosondes, lidars, and RO, spanning a vertical range from the lower troposphere to the upper stratosphere. The focus is on assessing climate trends and on identifying the degree of consistency among the observational systems. The results show a robust cooling of the stratosphere of about 1–3 K, and a robust warming of the troposphere of about 0.6–0.8 K over the last four decades (1979– 2018). Consistent results are found between the satellite-based layer-average temperatures and vertically resolved radiosonde records. The overall latitude–altitude trend patterns are consistent between RO and radiosonde records. Significant warming of the troposphere is evident in the RO measurements available after 2001, with trends of 0.25–0.35 K per decade. Amplified warming in the tropical upper-troposphere compared to surface trends for 2002–18 is found based on RO and radiosonde records, in approximate agreement with moist adiabatic lapse rate theory. The consistency of trend results from the latest upper-air datasets will help to improve understanding of climate changes and their drivers

Silicalite-1 : stratégies d'obtention de nanocristaux sans défauts

National @ MATERIAUX+LBU:ATUInternational audienceNous montrerons que différentes méthodes post-synthčse peuvent ętre appliquées pour diminuer considérablement (voire réduire presque totalement) la densité de défauts dans le réseau de nanocristaux de silicalite-1. Parmi celles-ci, l'échange des défauts par des ions F- dans le solide issu de synthčse est une voie prometteuse car elle se fait sans modification de la taille et forme des cristaux [1]. Néanmoins, elle n'est réellement efficace que si elle est associée ŕ d'un autres traitements post-synthčse, comme par exemple la formation de nanoboîtes monocristallines [2]. Tous les divers traitements seront discutés et illustrés, et nous verrons qu'il est possible d'obtenir des nano zéolithes dont le nombre de défauts est tout aussi faible que celui de gros cristaux de zéolithes directement préparés en présence de HF

New routes to nanozeolite crystals with very few framework defects

International @ MATERIAUX+LBU:ATUInternational audienceIn zeolites, the absence of defects is generally associated to large crystals, obtained following the fluoride route. Defect-free nanosized zeolites are difficult to obtain by direct synthesis and their preparation remains a challenge. In the present work, a two-steps strategy has been applied to decrease the density of framework connectivity defects in nanosized silicalite-1 crystals. The formation of hollow structures removed the most defective parts of the crystals whereas treatment of the as-made hollow zeolites with NH4F considerably reduced the population of framework connectivity defects. The combination of both methods led to nanocrystals (size of ca. 150 nm) with unprecedented low amount of defects. 29Si NMR of the defect-free zeolites show highly resolved patterns, similar to those observed on large zeolite crystals obtained in the presence of fluoride species. This route opens new opportunities for the preparation of very small hydrophobic zeolite crystals