How gender- and violence-related norms affect self-esteem among adolescent refugee girls living in Ethiopia.

BACKGROUND: Evidence suggests adolescent self-esteem is influenced by beliefs of how individuals in their reference group perceive them. However, few studies examine how gender- and violence-related social norms affect self-esteem among refugee populations. This paper explores relationships between gender inequitable and victim-blaming social norms, personal attitudes, and self-esteem among adolescent girls participating in a life skills program in three Ethiopian refugee camps. METHODS: Ordinary least squares multivariable regression analysis was used to assess the associations between attitudes and social norms, and self-esteem. Key independent variables of interest included a scale measuring personal attitudes toward gender inequitable norms, a measure of perceived injunctive norms capturing how a girl believed her family and community would react if she was raped, and a peer-group measure of collective descriptive norms surrounding gender inequity. The key outcome variable, self-esteem, was measured using the Rosenberg self-esteem scale. RESULTS: Girl's personal attitudes toward gender inequitable norms were not significantly predictive of self-esteem at endline, when adjusting for other covariates. Collective peer norms surrounding the same gender inequitable statements were significantly predictive of self-esteem at endline (ß = -0.130; p  =  0.024). Additionally, perceived injunctive norms surrounding family and community-based sanctions for victims of forced sex were associated with a decline in self-esteem at endline (ß = -0.103; p  =  0.014). Significant findings for collective descriptive norms and injunctive norms remained when controlling for all three constructs simultaneously. CONCLUSIONS: Findings suggest shifting collective norms around gender inequity, particularly at the community and peer levels, may sustainably support the safety and well-being of adolescent girls in refugee settings

Complete redox exchange of indium for Tl+ in zeolite A. Synthesis and crystal structure of fully indium-exchanged zeolite A

Indium has replaced all of the TIC ions in fully dehydrated fully Tl+-exchanged zeolite A by a solvent-free redox ion-exchange reaction with In metal at 623 K. The crystal structures of the zeolite before (Tl-12-A) and after the reaction, followed by washing with water and redehydration at 350 degrees C for 2 days (In-10-A . In), have been determined by single-crystal X-ray crystallography at 21 degrees C. In-10-A . In, eleven In atoms or ions per unit cell are distributed over seven crystallographically distinct positions. Seven In occupy three threefold-axis equipoints: four In+ ions lie opposite B-rings in large cavity, and two In2+ and one In+ lie opposite B-rings in the sodalite unit. Three In+ ions per unit cell are found at two different 8-ring positions, 1.5 on the 8-ring plane and 1.5 off. Finally, one In-0 atom per unit cell is found at two quite unusual positions: half an In-0 at the center of sodalite unit and the other half In-0 opposite a 4-ring relatively deep in the large cavity. These In atoms associate with In ions, likely forming (In-5)(8+) clusters in half of the sodalite units and (In-3)(2+) clusters in half of the large cavities.X11sci

Crystal structure of indium-exchanged zeolite a containing sorbed disulfur

Molecules of S-2 are sorbed by dehydrated fully indium exchanged zeolite A from S(g) at 623 K. The crystal structure of dehydrated In8Si12Al12O48.(In)(0.75)(S-2) (R-1 = 0.053, R-2 = 0.050, and a = 12.090(2) Angstrom) has been studied by single-crystal X-ray diffraction methods at 294 K using the space group . The complex structural results are interpreted as follows. Each unit cell contains eight indium cations, 0.75 indium atoms, and two sulfur atoms. Six In ions per unit cell are found at four nonequivalent 3-fold axis equipoints: two In+ ions and 0.5 In3+ ions lie opposite six-rings in the large cavity, and three In2+ ions and 0.5 In+ ions Lie opposite six-rings in the sodalite unit. Two In+ ions per unit cell are found at eight-ring positions, off the plane. Three-quarters of an indium per unit cell, as near-neutral atoms associated with In2+ cations, are found at the centers of the sodalite units. The distances of In+, In2+, and In3+ to the nearest framework oxygens are ca. 2.55, 2.37, and 2.26 Angstrom, respectively. The structure may be viewed as having two kinds of "unit cells." Unit cell 1 (In-8-A .(In)(S-2), 75%) contains the (In-5)(8+) cluster (four In2+ ions tetrahedrally arranged about an In-0 in the sodalite unit (In2+-O = 2.37(1) Angstrom and In-0-In2+ = 2.75(2) Angstrom)). Unit cell 2 (In-8-A .(S-2), 25%) has two In3+ ions. In each large cavity, one atom of a disulfur molecule (S-S = 2.13(13) Angstrom) associates with three framework oxygens at 3.11(11) Angstrom, and the other sulfur atom bridges between two In+ ions at 3.26(3) and 3.37(19) Angstrom.X1122sciescopu

Complete redox exchange of indium for Tl+ in zeolite A. Crystal structures of anhydrous Tl-12-A and In-10-A center dot In. Indium appears as In2+, In+, and In-0. The clusters(In-5)(8+) and (In-3)(2+) are proposed

Indium has replaced all of the Tl+ ions in fully dehydrated fully Tl+(-)exchanged zeolite A by a solvent-free redox ion-exchange reaction with In metal at 623 K. The crystal structures of the zeolite before (Tl12Si12-Al12O48: a = 12.153(4) Angstrom, R-1 = 0.054, and R-2 = 0.060) and after the reaction, followed by washing with water and redehydration at 623 K (In10Si12Al12O48. In: a = 12.098(2) Angstrom, R-1 = 0.063, and R-2 = 0.062), have been determined by single-crystal X-ray crystallography at 294 K using the space group Pm3m. In In-10-A . In, 11 In atoms or ions/unit cell are distributed over seven crystallographically distinct positions. Seven In ions occupy 3-fold-axis equipoints: four In+ ions lie opposite 6-rings in large cavity (In(1)), and two In2+ (In(2)) and one In+ (In(3)) lie opposite 6-rings in the sodalite unit. Three In+ ions per unit cell are found at two different 8-ring positions: 1.5 on the 8-ring plane (In(4)) and 1.5 off(ln(5)). Finally, one In-0 atom per unit cell, probably associated with In ions, is found at two quite unusual positions: one-half of an In-0 lies at the center of sodalite unit (In(6)) and the other half of the In-0 is opposite a 4-ring relatively deep in the large cavity (In(7)). The crystal structure of In-10-A . In is viewed as a mixture of two kinds of ''unit cells,'' In-8-A . In and In-12-A . In, each with a cationic charge of 12+. By their approach distances to framework oxygens, the ionic radii of In+ and In2+ are ca. 1.23 and 1.04 Angstrom, respectively. The In(6) and In(7) positions lie deep within cavities where they approach only In cations. This suggests the existence of tetrahedral (In-5)(8+) clusters (four In2+ ions at In(2) with an In-0 atom at their center at In(6), In(2)-In(6) distance = 2.754(2) Angstrom in half of the sodalite units (In-8-A . In), and bent (In-3)(2+) clusters In(1)-In(7)-In(1) angle = 148.0(9)(0) and In(1)-In(7) = 3.073(8) Angstrom) in half of the large cavities (In-12-A . In).X1126sciescopu

PREPARATION, CRYSTAL STRUCTURE, AND THERMAL STABILITY OF THE CADMIUM SULFIDE NANOCLUSTERS CD6S44+ AND CD2NA2S4+ IN THE SODALITE CAVITIES OF ZEOLITE A (LTA)

The crystal structure and thermal stability of two cadmium sulfide nanoclusters prepared in zeolite A (LTA) have been studied by XPS, TGA, and single-crystal and powder XRD. The crystal structures of parallel to Cd2.4Na3.2(Cd6S4)(0.4)(Cd2Na2S)(0.6)(H2O)(>= 5.8)parallel to[Si12Al12O48]-LTA (a = 12.2919(7) A, crystal 1 (hydrated)) and parallel to Cd4Na2(Cd2O)(Na2O)parallel to[Si12Al12O48]-LTA (a = 12.2617(4) A, crystal 2 (dehydrated)) were determined by single-crystal methods in the cubic space group Pm(3)over bar>m at 294(1) K. Crystal 1 was prepared by ion exchange of Na-12-LTA in an aqueous stream 0.05 M in Cd2+, followed by washing in a stream of water, followed by reaction in an aqueous stream 0.05 M in Na2S. Crystal 2 was made by dehydrating crystal 1 at 623 K and 1 x 10(-6) Torr for 3 days. In crystal 1, Cd6S44+ nanoclusters were found in and extending out of about 40% of the sodalite cavities. Central to each Cd6S44+ cluster is a Cd4S4 unit (interpenetrating Cd2+ and S2- tetrahedra with near T-d symmetry, Cd-S = 2.997(24) A, Cd-S-Cd = 113.8(12)degrees, and S-Cd-S = 58.1(24)degrees). Each of the two remaining Cd2+ ions bonds radially through a 6-ring of the zeolite framework to a sulfide ion of this Cd4S4 unit (Cd-S = 2.90(8) A). In each of the remaining 60% of the sodalite cavities of crystal 1, a planar Cd2Na2S4+ cluster was found (Cd-S/Na-S = 2.35(5)/2.56(14) A and Cd-S-Cd/Na-S-Na = 122(5)/92(7)degrees). Cd6S44+ and Cd2Na2S4+ are stable within the zeolite up to about 700 K in air. Upon vacuum dehydration at 623 K, all sulfur was lost (crystal 2). Instead as anions, only two oxide ions remain per sodalite unit. One bridges between two Cd2+ ions (Cd2O2+, Cd-O = 2.28(3) A) and the other between two Na+ ions (Na2O, Na-O = 2.21(10) A).X111819sciescopu

Crystal Structures of Vacuum-Dehydrated Ni2+-Exchanged Zeolite Y (FAU, Si/Al=1.69) Containing Three-Coordinate Ni2+, Ni8O4 center dot xH(2)O(8+), x <= 4, Clusters with Near Cubic Ni4O4 Cores, and H+

Five single crystals of vacuum-dehydrated Ni2+-exchanged zeolite Y (Ni-Y) were variously prepared by the exchange of Na-Y or K-Y (Na-71- or K-71-Si121Al71O384, Si/Al = 1.69) with Ni2+ using flowing aqueous 0.05 M Ni(NO3)(2) at 294 or 353 K, followed by vacuum dehydration at 2.0 x 10(-6) Torr and 623 or 723 K. Their crystal structures and chemical compositions were determined using synchrotron X-radiation and energy dispersive X-ray (EDX) analyses to give Ni-n-Y, where 25.3 <= n <= 34.1 per unit cell: [NiuMvHw[Ni8O4 center dot xH(2)O](y)[Al(OH)(4)](z)l [Si121+zAl71-zO384]-FAU, where 21.4 <= n <= 24.2, M = Na and/or Ca, 3.3 <= v <= 13.1, 9.5 <= w <= 21.6, 2 <= x <= 4, 0.3 <= y <= 3.2, and 0 <= z <= 2.5. In each of the five crystal structures (space group Fd(3)m; mean a = 24.47 A), Ni2+ is found at sites I, I&apos;, a second I&apos;, II&apos;, and sometimes 11; unexpectedly, Na+ and Ca2+ are found at another site It. Two extra-framework oxygen positions (O-f), one in the sodalite cavity and the other nearby in the supercage, are seen on 3-fold axes in all crystals. They bond to Al3+ and Ni2+ ions in the sodalite cavities to form Al(OeH)(4)(-) and Ni-8(O-e)center dot xH(2)O(e)(8+) clusters with Ni-4(O-e)(4) cores, and with framework oxygens (O-f) to give trigonal bipyramidal Ni(O-f)(3)(O-e)(2)(2+) and trigonal pyramidal Ni(O-f)(3)(O-e)(2)(2+.) At site I (centers of double 6-rings) in the Na-Y crystal that was Ni2+-exchanged at 294 K, similar to 14 Ni2+ ions per unit cell each coordinate octahedrally to six framework oxygen atoms. The Ni2+ ions at the first F site are 3-coordinate near planar in all crystals. The Ni2+ ions at the second Y site are members of the Ni4O4 cores, tetrahedrally distorted cubes with Ni-O = 2.199(13) angstrom and O-Ni-O = 79.6(9)degrees in a representative crystal; these Ni2+ ions are distorted octahedral with three O-e&apos;s of the cluster and three Of&apos;s. The Ni2+ ions at sites II&apos; and II are 3-, 4-, or 5-coordinate. Al(OH)(4)(-) from framework dealumination centers some sodalite cavities in four of the five crystals; their number increased with both ion-exchange and dehydration temperatures, suggesting that dealumination occurred during both processes. The number of Ni-2+ ions per unit cell increases with Ni2+-exchange temperature and is greater with K-Y than with Na-Y, perhaps because the larger K+ ions are more loosely held. The leaving cation affects the Ni2+ distribution over the available sites, perhaps via the level of Ni2+-exchange. Both a greater degree of Ni2+-exchange and a higher dehydration temperature cause more Ni8O4 center dot xH(2)O(8+) clusters to form, leaving fewer Ni2+ ions at sites I and II. As more Ni8O4 center dot xH(2),O8+ formed, more H+ ions were produced. Some H+ and some 3- and 4-coordinate Ni2+ ions are easily accessible for catlysis.X112624sciescopu

Detailed Determination of the Tl+ Positions in Zeolite Tl-ZSM-5. Single-Crystal Structures of Fully Dehydrated Tl-ZSM-5 and H-ZSM-5 (MFI, Si/Al=29). Additional Evidence for a Nonrandom Distribution of Framework Aluminum

The structures of the fully exchanged, fully dehydrated zeolites Tl-ZSM-5 (a = 20.064(1), b = 19.946(1), c = 13.416(1) angstrom) and H-ZSM-5 (a = 20.079(1), b = 19.948(1), c = 13.419(1) angstrom) have been determined crystallographically using modestly twinned single crystals and synchrotron X-radiation. They were refined in the orthorhombic space group Pnma to R-1 = 0.071 and 0.066 with 3962 and 4278 reflections, respectively, for which F-o > 4 sigma(F-o). The geometry of the zeolite framework in both crystals (MFI, Al3,2Si92.8O192, Si/Al 29) is very similar to that in earlier determinations. The ZSM-5 framework and Tl+ positions are described using the four nonequivalent partially overlapping 10-rings (R), the two channel systems (C), the channel intersection volume, and the cove of the ZC. The latter two comprise the conventionally defined cavity. The zigzag (sinusoidal) channel (ZC) passes through R1, R3, and R4; the straight channel (SC) passes through R2. A total of 3.3(2) Tl+ ions per unit cell were found scattered among 18 crystallographically distinct positions. Based on their positions near R1, R2, and R3, these positions may be classified into three groups (Gn, n = 1-3), each with two general cation sites (Sn and Sn&apos;). Of the 18 Tl+ positions, six are in the intersection volume (at S2&apos; in G2), 11 are elsewhere in the ZC (in G1 and G3), and one is elsewhere in the SC (at S2) just outside the intersection volume. Among the six general cation sites, S1&apos; at the mouth of the cove has the highest Tl+ population, 28% of the total. Of the 18 Tl+ positions, 14 bond strongly to framework oxygen atoms with 2.68(4) T6. The preference of Al for the T10 site remains when longer, less reliable but more comprehensive, Tl-O bond length criteria are used. Using Tl-O T6 similar to T9 > T5 > T4 > T2 > T12 > T7 > T11, and with Tl-O T3 > T2 > T12 > T6 similar to T9 > T5 > T4 > T8 > T7 > T11 > T1. T10 is a member of R4, the 10-ring that is common to the intersection volume and the cove.X111613sciescopu

SINGLE CRYSTAL STRUCTURE OF ZEOLITE A (LTA) CONTAINING AG4CL4 NANOCLUSTERS AND REDUCED 1,3,5-TRIPYRYLIUM DIMERS WITH REMARKABLY SHORT 2.43 ANGSTROM INTERPLANAR SPACINGS

A single crystal of Ag-12-A (zeolite LTA) was prepared by the dynamic ion-exchange of Na-12-A with aqueous 0.05 M AgNO3. It was washed with CH3OH and allowed to react with a stream of 0.05 M KCl in CH3OH at 294 K. The crystal structure of the product vertical bar K2.35Ag1.1(Ag4Cl4)(0.45)(C3H3O3)(1.1)(K3Cl)(3.45)(K-3(OH)(2))(0.55)(H2O)(>= 3.0)vertical bar-[Si12Al12O48]-LTA (a = 12.292(1) angstrom) was determined by single-crystal X-ray diffraction in the cubic space group Pm (3) over barm at 294 K. It was refined to the final error index, R-1 = 0.052, based on the 371 reflections for which F-o > 4 sigma(F-o). Ag4Cl4 nanoclusters were found in about 45% of the sodalite cavities. Each Ag4Cl4 cluster (interpenetrating tetrahedra; symmetry T-d, Ag-Cl = 3.105(17) angstrom) is held in place by the coordination of each of its four Ag+ ions to three oxygens of the zeolite framework (Ag-O = 2.493(5) angstrom) and by the coordination of each of its four Cl- ions to a K+ ion through a 6-ring (Cl-K = 2.70(3) angstrom). In each of the remaining 55% of the sodalite cavities, two reduced planar 1,3,5-tripyrylium cations, [(CH)(3)O-3](2)(2+) (C-O = 1.52(3) angstrom), are found. These parallel eclipsed rings (symmetry D-3d) have an interplanar distance of only 2.43 angstrom due to sigma double bonding between the rings, the result of four electrons in 12-center bonding pi* orbitals, and to polar attraction. Each ring makes three strong hydrogen bonds (CH center dot center dot center dot O = 2.84(3) angstrom) to oxygens of the zeolite framework, and a Ag+ ion coordinates to the three oxygens of one ring (Ag-O = 2.68(9) angstrom). The large cavities are filled with K+, Cl-, Ag+, OH-, and H2O; the K3Cl2+ unit predominates. The 1,3,5-tripyrylium ring, isoelectronic with benzene, had not been reported before.X1133sciescopu