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Abstract: An in situ high-pressure X-ray diffraction study has been carried out at room temperature up to 9.26 GPa on synthetic Mn2Sb2O7 having a weberite-3T structure. A 2nd-order Birch–Murnaghan Equation of State (EoS) was used to refine the pressure–volume data. The refinement of the unit-cell volume and of the isothermal bulk modulus at room pressure leads to: V 0 = 782.7(2), K T0 = 150(1) GPa. Unit-cell parameters decrease gradually as a function of pressure with a bulk modulus anisotropy scheme, with a being the softest direction. The overall mean polyhedral distances are quite constant, indicating a scarce compressibility of both the A and B polyhedra in the pressure range investigated. The compressional behaviour of Mn2Sb2O7 is compared with that shown by ingersonite, Ca3MnSb4O14, and synthetic orthorhombic Ca2Sb2O7. [Copyright &y& Elsevier]

Abstract: An in situ high-pressure X-ray diffraction study has been carried out at room temperature up to 9.23 GPa on a crystal of Ca2Sb2O7 having a weberite-2O structure synthesized by solid-state reaction. A 2nd-order Birch–Murnaghan Equation of State (EoS) was used to refine the pressure–volume data. The refinement of the unit-cell volume and of the isothermal bulk modulus at room pressure leads to: V 0 = 555.8 (1), KT 0 = 154.6 (9) GPa. Unit-cell parameters decrease gradually as a function of pressure with a bulk modulus anisotropy scheme Ka 0 > Kb 0 > Kc 0, with c being the softest direction. The compressional behavior of Ca2Sb2O7 is compared with that shown by ingersonite, Ca3MnSb4O14, a mineral showing a weberite-3T structure. [Copyright &y& Elsevier]

Crystallization of rifaximin from 2-(2-ethoxyethoxy)ethanol (Transcutol®, DEGME or DEGEE), an inactive ingredient approved by the FDA and a solvent commonly used in the pharmaceutical and cosmetic fields, affords a crystalline form of the API with better solubility properties with respect to the known crystalline hydrates, which are characterized by a very low solubility in water and in buffered solutions. The new form, named rifaximin τ, is an anhydrous solvate, fully characterized by single crystal X-ray diffraction, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Solubility properties were also investigated and compared with known forms of rifaximin. Rifaximin τ combines a high dissolution rate, comparable to that of amorphous rifaximin, with a high storage stability, as in its solid form it is not affected by exposure to humidity. [ABSTRACT FROM AUTHOR]

The dark colour of some excavated architectural elements of the Ploutonion, in the archaeological site of Hierapolis of Phrygiae (Turkey), was investigated. The Ploutonion, visited by numerous ancient writers, such as Cicero and Strabo, was a sanctuary dedicated to Pluto and Kore, constructed during the early Imperial period above the entrance to a natural cave, from which thermal waters and poisonous gases emerge. It was used for sacred rituals: sacrifices, incubation and healing. A multi‐analytical approach (X‐ray diffraction, X‐ray fluorescence, optical and electronic microscopy, and chemical analyses of the thermal spring water) was used in order to define the composition and origin of darkening phenomena of some architectural elements of the Ploutonion. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new probe was designed, synthesized and characterized using NMR, mass and single crystal XRD studies. • The probe exhibited high selectivity and sensitivity towards cyanide in an aqueous solution. • A fluorescence turn-on process via deprotonation of phenolic –OH group was proposed. • The proposed sensing mechanism and optical properties were investigated using DFT and TD-DFT calculations. • The probe was utilized to detect cyanide in food materials and HeLa cells and to determine in natural water samples. A simple fluorescent probe (KS4) containing multiple reaction sites (phenolic –OH, imine and C = C bonds) is successfully synthesized and characterized using 1H NMR, 13C NMR, mass and single crystal XRD techniques. KS4 exhibits high selectivity towards CN– over a wide range of common anions in H 2 O:DMSO (1:1 v/v) leading to an amazing turn-on fluorescence at 505 nm via deprotonation of the phenolic –OH group. The limit of detection (1.3 µM) for CN– was much below the standard (1.9 µM) set by the World Health Organization (WHO). Stoichiometry of the interaction between KS4 and CN– was ascertained as 1:1 by the Job's plot method and the binding constant was determined to be 1.5x104 M−1. Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) based theoretical insight has been appealed to understand the optical properties of KS4 before and after the addition of CN– ion. The probe shows respectable real-time applicability for qualitative detection of CN– in almond and cassava powder as well as quantification in real water samples with excellent recoveries (98.8 – 99.8%). In addition, KS4 is found to safe towards living HeLa cells and successfully applied to the detection of endogenous cyanide ions in HeLa cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • The fluorescent probe AK1 sequentially sensed of Cu(II) and HS- ions via OFF-ON mechanism. • Job's plot, mass, FT-IR and EPR spectral data indicated formation of distorted octahedral [(AK1) 2 Cl(H 2 O)Cu] complex. • The LOD of AK1 for Cu(II) was 18 µM. • DFT and TD-DFT calculations strongly supported the optical experimental results. A new highly selective fluorescent probe AK1 was designed, synthesized and characterized, by conventional techniques, including single crystal XRD analysis, for sequential sensing of Cu(II) and HS- ions in an aqueous solution. The probe showed significant fluorescence quenching in the presence of Cu(II), while other metal ions produced only minor changes in the fluorescence of AK1. Job's plot and mass and EPR spectral analyses indicated a 2:1 binding stoichiometry between AK1 and Cu(II) ions. The limit of detection (LOD) of AK1 for Cu(II) was determined to be 7.7 µM, which is far lower than the USEPA limit (∼20 µM) for drinking water. Subsequently, the in situ generated AK1 -Cu(II) complex acts as a highly selective and sensitive probe for HS- ion, with an enhancement in fluorescence, even in the presence of different anions. Notably, the probe could detect and quantify Cu(II) and HS- ions in real water samples. Moreover, the optical properties of the probe in the absence and presence of Cu(II) and HS- ions were explained by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. [ABSTRACT FROM AUTHOR]

Arthropod communities of beach–dune systems are mainly composed by detritivorous species, apparently with overlapping trophic niches. This study aims at distinguishing the trophic roles of sympatric species, by using a biochemical approach in the analysis of gut contents. The digestion of seven trisaccharidic and disaccharidic substrates containing the glycosidic bond was tested in gut homogenates of 10 species of detritivorous insects and crustaceans from a Mediterranean beach–dune system (Tuscany, Italy). Glycosidase activities were compared between species. A dendrogram was determined separating species with different enzymatic activity spectra. The differences observed in the enzymatic activities may be related to a different use of the available food resources and interpreted as an opportunist nutrition of arthropod species sharing the same habitat. [ABSTRACT FROM AUTHOR]

To investigate the behavior of the As4S4 molecule within a crystal-chemical environment differing from realgar, α-As4S4, and its high-temperature polymorph, β-As4S4, the effects of the light exposure on the structure of the HgI2 ⋅ As4S4 adduct have been studied. The structure of this compound consists of a packing of nearly linear HgI2 molecules and As4S4 cage-molecules. A crystal [V = 1295.9(4) ų] was exposed to filtered polychromatic light (550 nm long-wavelength pass filter). A marked increase of the unit-cell volume as a function of the exposure time was observed up to V = 1338.9 ų at 3060 min of exposure. Structure refinements indicated that the increase of the unit-cell volume is to ascribe to the formation of an increasing fraction (up to 59%) of pararealgar replacing the realgar-type molecule. After this point, further light-exposure did not cause any further increase of the lattice parameters. On the contrary, a slow, continuous decrease of the unit-cell volume down to 1292.9 ų occurred by keeping the crystal in the dark (39 days). The "reverse" evolution of the unit-cell parameters in the dark almost overlap that observed during the light-induced process and the structural model obtained after the "dark stage" was found to be identical to that of the unaltered crystal, although the diffraction quality was lower and powder-like diffraction rings were observed together with single-crystal reflections. Apart from few peaks belonging to the original unaltered HgI2 ⋅ As4S4 adduct, most of the collected peaks can be assigned to β-As4S4. This feature could indicate decomposition into micro-crystalline β-As4S4 and HgI2; no diffraction effect ascribable to any HgI2 phase, however, was observed. Micro-Raman spectra were collected on crystals exposed to the above-mentioned wavelength light for increasing times (up to 3000 min). The peak at 274(±1) cm-1 whose intensity increases as a function of the exposure time confirms the transition from a realgar- to a pararealgar-type molecule in the HgI2 ⋅ As4S4 adduct. [ABSTRACT FROM AUTHOR]

Talitrus saltator biology, population dynamics, and reproduction were studied more or less simultaneously at three sand beaches: Lavos, on the western coast of Portugal; Collelungo, on the Italian coast of the Thyrrenian Sea; and Zouara, on the northern coast of Tunisia. The species exhibited a consistent pattern of aggregated distribution. Densities were higher at Lavos than at Collelungo and Zouara. Reproduction took place from early March to late September at Lavos and Collelungo, and from late February to early November at Zouara. The average sex ratio was favourable to males at Lavos and Collelungo, and to females at Zouara. Based on data from Lavos, the population abundance was positively correlated with temperature, while the percentage of juveniles in the population was positively correlated with temperature and sediment moisture. Adult individuals from the Atlantic population were larger than the Mediterranean ones, while newborn individuals from the Mediterranean were slightly larger than Atlantic ones. Life span was estimated at 7–11 months at Lavos, 6–9 months at Collelungo, and 6–8 months at Zouara. Cohorts born at the beginning of the reproductive period tend to have shorter lives than the ones born later in the season, with longer life spans occurring in cohorts that crossed the winter to breed in the next year. The minimum period necessary for sexual differentiation after birth was estimated at ±4 weeks at Lavos, ±3 weeks at Collelungo, and ±4.5 weeks at Zouara, for males, and ±6 weeks at Lavos, and ±5 weeks at Collelungo and Zouara, for females. The period necessary for female's sexual maturation after being born was estimated at ±10 weeks at Lavos, and ±8 weeks at Collelungo and Zouara. At the studied sites, T. saltator appeared as semiannual species, with iteroparous females appearing to produce at least two broods per year, and exhibited a bivoltine life cycle. Growth production (P) was estimated at 0.74 g m−2 yr−1 ash-free dry weight (AFDW; 17.7 kJ m−2 yr−1) at Lavos, 0.12 g m−2 yr−1 AFDW (2.8 kJ m−2 yr−1) at Collelungo, and 0.61 g m−2 yr−1 AFDW (14.3 kJ m−2 yr−1) at Zouara. Elimination production (E) was estimated at 1.40 g m−2 yr−1 AFDW (33.5 kJ m−2 yr−1) at Lavos, 0.20 g m−2 yr−1 AFDW (4.8 kJ m−2 yr−1) at Collelungo, and 1.11 g m−2 yr−1 AFDW (26.6 kJ m−2 yr−1) at Zouara. The average annual biomass (B¯) (standing stock) was estimated at 0.13 g m−2 at Lavos, 0.014 g m−2 at Collelungo, and 0.084 g m−2 at Zouara, resulting in P/B¯ ratios of 5.7 at Lavos, 8.2 at Collelungo, and 7.3 at Zouara, and E/B¯ ratios of 10.8 at Lavos, 14.4 at Collelungo, and 13.1 at Zouara. The present results, combined with information from literature, revealed a geographic variation in T. saltator populations with regard to their morphological characteristics, growth rates, life spans, and life cycles. [Copyright &y& Elsevier]

A comparative faunal analysis was carried out in sandy littoral localities differing both morphologically and in human impact. The study sites were located in the western Mediterranean basin along the coasts of Morocco, Tunisia, the Maltese Islands and Italy. These were typical beach–dune ecosystems more (Smir, Morocco; Zouara, Tunisia; Burano, Italy) or less (Ir-Ramla tat-Torri, Malta and Ir-Ramla l-Hamra, Gozo) structurally developed accordingly.Species richness was evaluated using standard trapping techniques with pitfall traps along the transects perpendicular to the shoreline. Only isopods and coleopterans were used in the analysis. In each locality, an analysis was conducted on both the beach and the dune separately, and on the entire ecosystem in the two seasons (spring and autumn). Species were studied both quantitatively and qualitatively using ecological coefficients (relative abundance) and Fisher''s diversity index. To evaluate the evenness of the community, Shannon–Weaver index was calculated and compared with Brillouin index. For both indices, the maximum values were computed and were used to obtain the evenness of the community through Pielou index. In addition, Simpson''s dominance index was considered. Percentages of similarities between localities were analysed in the two seasons and in total using the Renkonen index. The overall analysis showed that general trends could be found for both orders that were studied and gave indications on habitat quality. The study showed that when monitoring was carried out systematically both in space and time, arthropods could be used as important tool to assess beach health. [Copyright &y& Elsevier]

Temporal and spatial distribution patterns of a population of Talitrus saltator living on the Tyrrhenian coast of Tuscany (Italy) were studied. Bimonthly surveys were performed from March 1991 to January 1992 along transects using a standard system of pitfall traps and sieves for surface-active and burrowed individuals, respectively. Captured individuals were subdivided into sex and age classes (on the basis of the number of articles of the flagellum of the second antenna). Abundances were calculated for each sampling period and sex ratios were determined. For each sampling period the mean hour of surface activity was calculated together with the mean zonation of both surface-active and burrowing sandhoppers belonging to the different sex and age classes. Shifts in mean zonation between the resting and active phase were also determined. For each category of sex, age, and reproductive phase, simple and multiple regression analyses were used to find relationships of the mean zonation of surface-active animals with climatic data, and of the number of burrowed individuals with surface sand parameters recorded in correspondence to the sieves. On the whole, the results show that this Tyrrhenian population of T. saltator exhibited a bivoltine reproductive cycle and that the sex ratios of active sandhoppers were male or female biased according to the season. The variations in the mean hour of surface activity and in the zonation patterns of sandhoppers depended more on the age than on the sex. Furthermore distribution patterns were generally related to seasonal changes in the local climatic and substrate parameters. The observed differences between burrowing and activity zonations were interpreted on the basis of the nocturnal migrations of the different categories. [ABSTRACT FROM AUTHOR]

Presents a study that examined the spatial distributions of sand beach arthropods at Zouara, a beach dune system along the northwestern coast of Tunisia. Assessment of the capture frequency of the arthropod species; Analysis of environmental parameters in the beach dune system; Differences in the seasonal distribution of the species.

During a field study on the eco-ethology of sandy beach arthropods conducted along the French Atlantic Coast it emerged that Tylos europaeus, Phaleria cadaverina and Labidura riparia were among the most abundant species that lived in the eulittoral. Tetradirectional pitfall traps, placed from the base of the dune to the tidal limits, were used. The traps intercepted surface-active arthropods, and the number of traps varied according to the levels of the tides. Data were recorded hourly during two periods corresponding to a spring tide and the following neap tide. At the saine time the most important environmental parameters were registered each hour. The results indicate that all three species show prevalently nocturnal surface activities. For T. europaeus and Ph. cadaverina an influence of the synodic and tidal phases was found on the zonation of the surface activity and on the extent of movement. The latter was due to the greater or smaller distances that the isopods and tenebrionids had to move from the diurnal burrowing sites to the foraging zones. For L. riparia no variations in the total mean zonations were found between the two synodic phases, and only at neap tide were seaward, followed by landward movements found. Multiple regression analysis showed that the environmental parameters registered in this period were never limiting, as threshold values in this case probably were not reached. [ABSTRACT FROM AUTHOR]