Impact of Lanthanide (Nd3+, Gd3+, and Yb3+) Ionic Field Strength on the Structure and Thermal Expansion of Phosphate Glasses

Phosphate glasses containing Nd3+, Gd3+, and Yb3+ as lanthanide ions are attractive for applications in laser materials, phototherapy lamps, and solar spectral converters. The composition-structure-property relation in this type of glass system is thus of interest from fundamental and applied perspectives. In this work, the impact of the differing ionic radius of Nd3+, Gd3+, and Yb3+ and consequent field strength on the physical properties of phosphate glasses is investigated, focusing ultimately on thermal expansion effects. The glasses were made by melting with a fixed concentration of the lanthanide ions having 50P2O5-46BaO-4Ln2O3 nominal compositions (mol %) with Ln = Nd, Gd, and Yb. The investigation encompassed measurements by X-ray diffraction (XRD), optical spectroscopy, density, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and dilatometry. XRD supported the amorphous nature of the glasses, whereas absorption and photoluminescence spectra showed the optical features of the Nd3+, Gd3+, and Yb3+ ions in the glasses. Oxygen speciation by XPS indicated an increase in nonbridging oxygens for the larger radii Nd3+ and Gd3+ ions relative to the host, contrasting with Yb3+. Phosphorus XPS analysis further supported the hypothesis that the P 2p binding energies of the glasses increased with the cation field strength of the lanthanides. The Raman spectra were interpreted based on glass depolymerization effects and the impact of Ln3+ ions with high field strength. Particularly, the band position of the symmetric out-of-chain nonbridging oxygen stretch, νs(PO2-), shifted to higher frequencies correlating with the Ln3+ field strength. Dilatometry ultimately revealed a steady decrease in the coefficient of thermal expansion for the glasses, which correlated linearly with Ln3+ field strengths and thus indicated to sustain increased glass rigidities. The various analyses performed thus illuminated the structural foundation of the thermomechanical behavior of the glasses connected with changes in the Ln3+ field strengths.

Mapping cumulative compound hydrometeorological and marine-induced risks on the NW Mediterranean coast

Coastal risks in the Mediterranean are a result of the complex interplay between hydrometeorological and marine hazards. The region encompasses areas with varying degrees of vulnerability to these hazards, as well as spatial variations in exposure values, making it essential to adopt a comprehensive and nuanced approach to risk assessment and management. It is worth noting that hydrometeorological hazards, such as flash floods, can often have a greater impact than strictly coastal hazards, highlighting the need to consider the full range of potential risks. Therefore, coastal managers must adopt a multi-hazard approach to make sound risk management decisions. This study addresses this need using an index-based framework that assesses the integrated risk in time and space (hereafter referred to as cumulative compound risk) in coastal zones by aggregating the main hydrometeorological and marine hazards, the vulnerability of the territory to both types of hazards, and values at exposure. The framework is designed for use at large spatial scales (applied to a 1100 km coastline in this study), with the basic spatial unit being relevant for management (here set as the municipality in this study). Its application enables the assessment of spatial variations in integrated risk as well as individual hydrometeorological and marine contributions. The combined use of the indices and cluster analysis helps identify similarities and differences in the risk profile of spatial units, and thus, define homogeneous areas from a risk management perspective. In this study, the framework was applied to the Spanish Mediterranean coastline, an area representative of the climatic, geomorphological, and socioeconomic conditions of the Mediterranean coast.

XANES analysis of phosphate glasses melted with Tb4O7 and SnO: evaluating the impact of valence states on structural, thermal, and luminescent properties

Barium phosphate glasses were prepared with 0.5 mol% Tb4O7 added alongside SnO up to 5 mol% with the purpose of evaluating the resulting terbium and tin oxidation states and their impact on glass structural, thermal, and luminescent properties. Following material synthesis by melt-quenching, the composition-structure-property investigation was pursued encompassing measurements by X-ray diffraction (XRD), X-ray absorption near-edge spectroscopy (XANES), Raman spectroscopy, differential scanning calorimetry (DSC), dilatometry, and photoluminescence (PL) spectroscopy. While XRD confirmed the amorphous nature of the glasses, results from XANES indicated that terbium occurs as terbium(III) with a predisposition for tin to exist as tin(IV) which decreased at high SnO content. The structural as well as the thermal properties appeared to be mostly impacted by the presence of tin(IV). Specifically, glass depolymerization was indicated to be induced by Sn4+ ions, and their concentration was observed to correlate with glass transition and softening temperatures. On the other hand, the tin(II) remnants were observed to exert an impact on the luminescent properties shifting light emission from the green towards the blue-green (cyan). It is indicated that Tb4O7 reacting to produce Tb2O3 supports the oxidation of tin(II) to tin(IV) which in turn dominates the physical properties. However, this was somewhat circumvented at the highest SnO content wherein tin(IV) appeared to be lower.

In Situ Optical Microspectroscopy Study of Isothermal Bleaching of γ-Irradiated International Simple Glass

The isothermal bleaching of γ-irradiated glass was studied at elevated temperatures (280-340 °C) by real-time in situ optical microspectroscopy for the first time. The study was performed on γ-irradiated (0.83 and 1.99 MGy) International Simple Glass (ISG) borosilicate nuclear waste simulant made by Mo-SCI Corporation (Rolla, MO, USA). The current investigation proposes real-time optical transmission methodology for the activation energy assessment of isothermal bleaching of γ-irradiated glass. The method is based on robust quantification of the Urbach energy decay rates and yields similar activation energies for both doses within ∼0.24-0.26 eV.

Eu3+ Concentration Effects in Phosphate Glasses: An Experimental Study Linking Structural, Thermal, and Optical Properties

Phosphate glasses incorporating large concentrations of Eu³⁺ ions are of interest for optical applications as their distinct red-emitting character resists deterioration with increasing Eu³⁺ content. Still, the low propensity for concentration quenching in these is not well understood, and thus evaluations linking structural, thermal, and optical properties with Eu³⁺ content are desired. In this work, 50P₂O₅-(50 - x)BaO-xEu₂O₃ (x = 0, 1, 2, 4, 6 mol %) glasses pertinent to photonics were prepared by melt-quenching and further scrutinized with regards to the composition-structure-property relationship. A comprehensive experimental investigation was carried out encompassing density and basic physical properties, X-ray diffraction (XRD), Raman scattering, dilatometry, differential scanning calorimetry (DSC), optical absorption, and photoluminescence (PL) spectroscopy with emission decay analysis. The data from six techniques are in strong agreement with the existence of a critical Eu₂O₃ concentration which divides the studied concentration range into two sections: (1) lower concentrations, up to about 2.5 (±0.1) mol %, with predominantly long-range (LR) effects of the modifier electrostatic field and (2) higher dopant concentrations, with predominantly short-range (SR) effects of the modifier field. The authors propose that LR interactions lead to shortening of the P-tetrahedral chains, while the SR interactions are expressed in increasing the covalent character of the bonds between the nonbridging oxygens and Eu³⁺ ions. Concentration correlations between diverse macroscopic data sets, such as densitometry, dilatometry, Raman scattering, calorimetry, and PL, concur synergistically, elucidating the microscopic physical LR-SR interplay between glass network former and the cationic electrostatic field of the modifiers.

Nanodiamond-promoted white light emission in Eu, Dy, and Cu-containing phosphate glass: quantitative analysis and colorimetric study

A thorough analysis of glass containing Eu₂ O₃ and Dy₂ O₃ , or Eu₂ O₃ , Dy₂ O₃ , and CuO melted together with nanodiamond powder was pursued based on measurements of optical absorption, photoluminescence (PL) emission and excitation spectra, and colorimetry. Nanodiamond facilitated the stabilization of Cu⁺ and Eu²⁺ ions with blue-emitting characteristics that, along with yellow-emitting Dy³⁺ and red-emitting Eu³⁺ led to the white light-emitting glass. Novel intensity notations implemented in intensity-based spectral ratios, and difference intensity correlation analysis were proposed for the assessment of PL properties. The chromaticity and correlated colour temperature of the emission were ultimately investigated as a two-parametric problem based on: (1) the different ionic components; and (2) the various excitation wavelengths employed. The optical analysis approach adds to the characterization methods to further fundamental understanding and provide helpful analytical tools for designing materials for tunable white light-emitting devices.

Tm3+ Ion Blue Emission Quenching by Pd2+ Ions in Barium Phosphate Glasses: Fundamental Analysis toward Sensing Applications

The quenching effect of Pd²⁺ ions on the blue emission from Tm³⁺ was investigated for the first time using barium phosphate glass as model matrix. Glasses containing fixed Tm₂O₃ at 0.5 mol % and PdO up to 0.3 mol % (added relative to P₂O₅) were prepared by melting and first characterized for basic structural properties by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Raman spectroscopy. Thermal properties were then evaluated by differential scanning calorimetry (DSC). The focus was thereafter on evaluating the optical properties by absorption and photoluminescence (PL) spectroscopy with decay kinetics assessment. XRD confirmed the amorphous nature of the glasses synthesized. The vibrational spectroscopy assessment consistently exhibited the IR- and Raman-active bands characteristic of phosphate glasses, showing no significant variation with PdO codoping. The DSC analysis revealed all glasses possessed high thermal stability assessed by the differences (ΔT = T_g - T_x ≥ 154 °C) between glass transition temperatures (T_g) and onset of crystallization (T_x). A tendency of the T_g values to increase with PdO contents was however exhibited. In addition, specific enthalpies of crystallization showed magnitudes decreasing with increasing PdO concentration, thus suggesting crystallization suppression by Pd²⁺. Concerning the optical properties, it was observed that codoping the glasses with PdO (0.1-0.3 mol %) led to the development of the visible Pd²⁺ d-d absorption band (peak ≈415-410 nm). In addition, drastic PL quenching of the Tm³⁺ blue emission around 452 nm (¹D₂ → ³F₄ transition) was induced by Pd²⁺. Analyzing PL decay curves obtained by exciting Tm³⁺ ions at 359 nm while monitoring 452 nm emission revealed decreased ¹D₂ state lifetimes. Thus, a potential of Tm³⁺ for analytical sensing of Pd²⁺ in various matrices was suggested. Ultimately determining quenching constants from the PL data and based on the comparison of results from emission intensity and decay rates, likely Tm³⁺ → Pd²⁺ energy transfer processes underlying the PL quenching were proposed.

Spectroscopic inquiry of CuO-doped borate glasses in the 50B2O3-25Li2O-25BaO ternary

Borate glasses with 50B₂O₃-25Li₂O-25BaO composition and CuO within 0.1-1.0 mol% relative to B₂O₃ have been prepared by the melting technique, and studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, optical absorption, and photoluminescence (PL) spectroscopy with decay kinetics assessment. A thermal dilatometric assessment was first carried out for the undoped glass, followed by a glass transition temperature (T_g) evaluation for all glasses by DSC. A propensity toward higher T_g values was indicated for high CuO concentrations, consistent with a higher BO₄ content being supported by copper ions as network modifiers. The glasses were all X-ray amorphous, whereas FT-IR spectra indicated the basic structural features of trigonal BO₃ units and BO₄ tetrahedra. Herein also, a tendency towards the 4-coordinated BO₄ units was indicated for the highest CuO contents concurring with the T_g trend. The optical absorption analysis showed that addition of CuO up to 1.0 mol% results in significant growth of the visible Cu²⁺ absorption band around 740 nm, with a decreasing trend in the optical band gap energies assessed through Tauc plots. Further analysis of the Urbach energies revealed declining values with copper doping indicating it favored a more uniform glass structure compatible with FT-IR data. An intrinsic luminescence was detected for the undoped borate glass displaying relatively long multi-exponential decay, which appeared to be quenched by Cu²⁺. The PL evaluation nevertheless supported the presence of Cu⁺ ions emitting broadly around 480 nm upon UV excitation at 250 nm. The decrease in the band gap energies is suggested to reflect the presence of ionic copper rather than an increase in non-bridging oxygens as commonly argued.

Study of the Influence of Sintering Atmosphere and Mechanical Activation on the Synthesis of Bulk Ti2AlN MAX Phase Obtained by Spark Plasma Sintering

The influence of the mechanical activation process and sintering atmosphere on the microstructure and mechanical properties of bulk Ti₂AlN has been investigated. The mixture of Ti and AlN powders was prepared in a 1:2 molar ratio, and a part of this powder mixture was subjected to a mechanical activation process under an argon atmosphere for 10 h using agate jars and balls as milling media. Then, the sintering and production of the Ti₂AlN MAX phase were carried out by Spark Plasma Sintering under 30 MPa with vacuum or nitrogen atmospheres and at 1200 °C for 10 min. The crystal structure and microstructure of consolidated samples were characterized by X-ray Diffraction, Scanning Electron Microscopy, and Energy Dispersive X-ray Spectroscopy. The X-ray diffraction patterns were fitted using the Rietveld refinement for phase quantification and determined their most critical microstructural parameters. It was determined that by using nitrogen as a sintering atmosphere, Ti₄AlN₃ MAX phase and TiN were increased at the expense of the Ti₂AlN. In the samples prepared from the activated powders, secondary phases like Ti₅Si₃ and Al₂O₃ were formed. However, the higher densification level presented in the sample produced by using both nitrogen atmosphere and MAP powder mixture is remarkable. Moreover, the high-purity Ti₂AlN zone of the MAX-1200 presented a hardness of 4.3 GPa, and the rest of the samples exhibited slightly smaller hardness values (4.1, 4.0, and 4.2 GPa, respectively) which are matched with the higher porosity observed on the SEM images.

Pd2+-induced quenching of the UV emission from Gd3+ ions in phosphate glass

This paper reports on the influence of Pd²⁺ ions on the ultraviolet emission from Gd³⁺, investigated in barium phosphate glass as model matrix. The glasses were prepared by the melting technique and characterized by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, optical absorption, and photoluminescence (PL) spectroscopy including decay kinetics assessment. The XRD data confirmed the amorphous nature of the glasses, whereas FT-IR spectra indicated the basic structural features of PO₄ tetrahedra. The optical absorption analysis showed that addition of PdO up to 0.3 mol% lead to significant growth of the visible Pd²⁺ d-d absorption band around 415 nm, with ultimately some decrease in the optical band gap energies assessed through Tauc plots. Further, significant PL quenching of Gd³⁺ ions emission around 312 nm was observed with increasing PdO contents, alongside increased decay rates for the ⁶P_7/2 emitting state in Gd³⁺. An analysis of quenching constants was ultimately performed comparing results from emission intensity with the decay rates. It is suggested that a Gd³⁺ → Pd²⁺ excitation transfer and/or absorption competition lead the quenching process with a contribution from a channel depopulating the ⁶P_7/2 metastable state.

Optical Spectroscopy and Excited-State Dynamics of Eu3+ -Doped Bismuth Borate Glasses Containing CuO

Bismuth borate glasses containing phosphors and luminescent rare-earths are of interest for applications in light-emitting devices. Herein, the influence of CuO impurities on red-emitting Eu³⁺ -doped bismuth borate glasses of the 25Bi₂ O₃ -15BaO-10Li₂ O-50B₂ O₃ type was investigated by various spectroscopic methods. The glasses were prepared by the melt-quench technique and characterized by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, UV/Vis optical absorption (OA), and photoluminescence (PL) spectroscopy including decay kinetics assessment. The XRD data confirmed the amorphous nature of the glasses whereas FT-IR spectra indicated the basic structural features of trigonal BO₃ units and BO₄ tetrahedra. The OA analysis showed that addition of CuO up to 0.5 mol% results in significant growth of the visible Cu²⁺ absorption band around 715 nm, with slight decrease in the optical band gap energies assessed through Tauc plots. A drastic PL quenching of Eu³⁺ ions emission was evidenced concurring with the detrimental effect of Cu²⁺ . The assessment of the Eu³⁺ emission decay curves revealed significant lifetime decrease of the ⁵ D₀ emitting state with increasing CuO concentration. An analysis of quenching constants was finally performed comparing results from integrated PL data with the emission decay rates. It is argued that the bismuth borate glass system supports an effective Eu³⁺ →Cu²⁺ energy transfer (more so than phosphates) in connection with a strong spectral overlap between Eu³⁺ emission and Cu²⁺ absorption.

Financing and implementation of adaptation measures to climate change along the Spanish coast

Understanding how we are adapting to climate change in coastal areas is an essential issue in the long-term coastal planning. While most of existing studies focus on mapping the current state of adaptation plans, there is a significant lack of studies on the current implementation of adaptation strategies. This study addresses this challenge by assessing how coastal adaptation is being financed and implemented in Spain. In the absence of a detailed roadmap for implementing the Spanish Strategy for Coastal Adaptation to Climate Change, we have analysed how adaptation has been and is currently being funded; which the rationale for investments along the territory is; how adaptation investments compare to regular coastal protection costs; and assessed when implemented measures are really adaptation ones. Our results show that the financing source clearly conditions the type of measures implemented, with those funded under the Environment Promotion Plan for Climate Change Adaptation (PIMA Adapta initiative) being dominated by classical coastal engineering actions, whereas ecosystem-related actions are mostly funded under the LIFE programme. In territorial terms, the Mediterranean coastal regions present the most important problems under current conditions and attract most of the funding. Most of the funded actions have been designed to solve current coastal problems, and although they indirectly contribute to adaptation by improving the coastal base status, they are not specifically designed for climate change. This misuse of the concept of adaptation measure will tend to the society to be overconfident about adopted actions whereas we are not progressing to real adaptation. To overcome this risk, it is necessary to have a clear roadmap for implementing adaptation measures together a proper financing structure.

Thermal and spectroscopic characterization of copper and erbium containing aluminophosphate glass

Thermal, Raman scattering, optical absorption, and photoluminescence characterizations were carried out on aluminophosphate glass containing Cu⁺/Cu²⁺ along with near-infrared (IR) emitting Er³⁺ ions of interest to photonic applications. Material synthesis was carried out by the melt-quench technique wherein Cu⁺ ions were incorporated at a high concentration by addition of 10 mol% of Cu₂O together with SnO. The copper oxide doping was recognized to result in a decrease of the glass transition temperature of the matrix, however Er³⁺ doping displayed opposite propensity. Raman measurements under 785 nm excitation were consistent with calorimetry data indicating that copper ions modify glass structural features. The degree of copper oxidation during material preparation was assessed quantitatively through the Cu²⁺ absorption feature around 850 nm. The presence of substantial Cu⁺ concurred with the significant red shift in the near-ultraviolet glass absorption edge, and was analyzed in the context of optical band gap determinations. An evaluation of the luminescence decay kinetics of Cu⁺ ions in the presence of Er³⁺ agreed with a non-radiative energy transfer which appeared more effective for excitation of Cu⁺ near the glass absorption edge at 400 nm. Such excitation was confirmed to result in the sensitized near-IR emission from Er³⁺ ions around 1.53 μm of interest to lasers, the telecommunications, and spectral conversion in photovoltaic cells.

Pseudomonas fluorescens LBUM677 differentially increases plant biomass, total oil content and lipid composition in three oilseed crops

AIMS

Pseudomonas spp. have been widely studied for their plant growth-promoting effects. However, their capacity to promote lipid accumulation in oilseed crops is not well characterized. In this study, we evaluated the effect of Pseudomonas fluorescens LBUM677 on lipid accumulation in three oilseed crops: soybean (Glycine max), canola (Brassica napus) and corn gromwell (Buglossoides arvensis), a plant of high nutraceutical interest for its accumulation of the omega-3 stearidonic acid.

METHODS AND RESULTS

Pot experiments were conducted under controlled conditions where seeds were inoculated or not with LBUM677 and plants were harvested at 4, 8 and 12 weeks. A qPCR assay specifically targeting LBUM677 was used in parallel to correlate LBUM677 soil rhizosphere competency to growth promotion and seed lipid accumulation. Total oil seed content and fatty acid composition were analysed at seed maturity. Results showed that LBUM677 was able to establish itself in the rhizosphere of the three plant species at similar levels, but it differentially increased plant biomass, total oil content and lipid composition in a plant-specific manner.

CONCLUSIONS

Despite some species-specific differences observed in P. fluorescens LBUM677's effect on different crops, the strain appears to be a generalist plant growth-promoting rhizobacteria of oilseed crops.

SIGNIFICANCE AND IMPACT OF THE STUDY

LBUM677 shows great potential to be used as an inoculum to promote oil yield and fatty acid accumulation in oilseed crops.

Thermal effects on the surface plasmon resonance of Cu nanoparticles in phosphate glass: impact on Cu+ luminescence

An evaluation of the effects of temperature on the optical properties of phosphate glass containing Cu nanoparticles (NPs) and Cu⁺ ions was carried out by means of optical absorption and photoluminescence (PL) spectroscopy measurements performed jointly in situ in the 298 to 573 K range. The surface plasmon resonance (SPR) of Cu NPs displayed a strong dampening effect with temperature, consistent with the thermal expansion of Cu NPs and an increase in the electron-phonon scattering rate. The PL of Cu⁺ ions in the glass with Cu NPs showed the thermal quenching effect connected with an increase in non-radiative relaxation processes. Moreover, a comparison with the precursor glass without NPs revealed that a lower activation energy for the thermal quenching of Cu⁺ PL results in the presence of Cu NPs for Cu⁺ sites emitting in resonance with the SPR. It is suggested that the increase in electron-phonon interaction in Cu NPs with temperature impacts the PL quenching of Cu⁺ ions the most. The current results suggest that a Cu⁺ → Cu NP resonant energy transfer supports a deactivation of the Cu⁺ emitting states with increasing temperature.

Optimal Use of Transient Elastography and Acoustic Radiation Force Impulse to Stage Liver Fibrosis in HIV/HCV-Coinfected Patients in Clinical Practice

OBJECTIVES

Liver fibrosis (LF) is crucial for the individualized management of patients with hepatitis C virus (HCV). We evaluated the concordance between two noninvasive methods for staging LF, transient elastography (TE) and acoustic radiation force impulse (ARFI), in patients coinfected with human immunodeficiency virus and HCV. We propose an algorithm for optimal use of both techniques in routine clinical practice.

METHODS

A total of 89 human immunodeficiency virus/HCV-coinfected patients underwent TE and ARFI on the same day. The kappa index was used to assess concordance between the techniques. An algorithm combining ARFI and TE was proposed based on the independent factors associated with a kappa index greater than or equal to 0.70, obtained from a multiple regression analysis. We performed a cost-effectiveness analysis. The study was approved by our institutional review board and all patients signed the informed consent.

RESULTS

Concordance between TE and ARFI for F2, F3, and F4 was 0.55, 0.59, and 0.69, respectively. Ultrasound normal spleen size (odds ratio [OR], 0.20; 95% confidence interval [CI], 0.05-0.91) and high viral load (OR, 0.36; 95% CI, 0.17-0.77) reduced the probability of agreement between TE and ARFI, whereas ultrasound normal left liver lobe size (OR, 3.32; 95% CI, 1.21-9.10) increased this probability. The algorithm revealed that LF was adequately assessed in 74.16%, with 25.84% of patients misclassified. The incremental cost-effectiveness ratio of TE compared with ARFI to increase concordance by 1% was €8.86.

CONCLUSIONS

Concordance between TE and ARFI was moderate. In the algorithm we proposed, ARFI was cost-effective as a first technique for the staging of LF in the study population.

Silicon-Induced UV Transparency in Phosphate Glasses and Its Application to the Enhancement of the UV Type B Emission of Gd3

The silicon route to improve the ultraviolet (UV) transparency in phosphate glasses is investigated and further exploited to enhance the UV type B (280-320 nm) emission of gadolinium(III) relevant for biomedical applications. The glasses were synthesized with a barium phosphate composition by melt-quenching in ambient atmosphere and the optical properties investigated by optical absorption and photoluminescence (PL) spectroscopy including emission decay kinetics. An improvement in the UV transparency was gradually developed for the glasses melted merely with increasing amounts of Si powder. A particular PL in the visible was also exhibited for such glasses under excitation at 275 nm, consistent with the presence of Si-induced defects. For Si-Gd codoped glasses, the UV transparency was likewise manifested, while the UV emission from Gd³⁺ around 312 nm was enhanced with the increase in Si concentration (up to ∼6.7 times). Moreover, along with the Gd³⁺ PL intensity enhancement, a linear correlation was revealed between the increase in decay times for the Gd³⁺⁶P_7/2-emitting state and the amount of silicon. It is then suggested that the improved PL properties of gadolinium(III) originate from the increased UV transparency of the host and the consequent precluding of a nonradiative energy transfer from Gd³⁺ to the matrix. Accordingly, a role of Si as PL quenching inhibitor is supported. The demonstrated efficacy of the Si-Gd codoping concept realized by a facile glass synthesis procedure may appeal to the application of the UV-emitting glasses for phototherapy lamps.

Microbial source tracking in shellfish harvesting waters in the Gulf of Nicoya, Costa Rica

Current microbial water quality monitoring is generally limited to culture-based measurements of fecal indicator bacteria (FIB). Given the many possible sources of fecal pollution within a watershed and extra-intestinal FIB reservoirs, it is important to determine source(s) of fecal pollution as a means to improve water quality and protect public health. The principal objective of this investigation was to characterize the microbial water quality of shellfish harvesting areas in the Gulf of Nicoya, Costa Rica during 2015. In order to achieve this objective, the specificity and sensitivity of 11 existing microbial source tracking (MST) PCR assays, associated with cows (BacCow), dogs (BacCan, DogBac), domestic wastewater (PMMoV), general avian (GFD), gulls (Gull2), horses (HorseBac, HoF), humans (HF183, HPyV), and pigs (PF), were evaluated using domestic wastewater and animal fecal samples collected from the region. The sensitivity of animal-associated assays ranged from 13 to 100%, while assay specificity ranged from 38 to 100%. The specificity of pepper mild mottle virus (PMMoV) and human polyomavirus (HPyV) was 100% for domestic wastewater, as compared to 94% specificity of the HF183 Bacteroidales marker. PMMoV was identified as a useful domestic wastewater-associated marker, with concentrations as high as 1.1 × 10⁵ copies/ml and 100% sensitivity and specificity. Monthly surface water samples collected from four shellfish harvesting areas were analyzed using culture-based methods for Escherichia coli as well as molecular methods for FIB and a suite of MST markers, which were selected for their specificity in the region. While culturable E. coli results suggested possible fecal pollution during the monitoring period, the absence of human/domestic wastewater-associated markers and low FIB concentrations determined using molecular methods indicated sufficient microbial water quality for shellfish harvesting. This is the first study to our knowledge to test the performance of MST markers in Costa Rica as well as in Central America. Given the lack of wastewater treatment and the presence of secondary sources of FIB, this study highlights the importance of an MST toolbox approach to characterize water quality in tropical regions. Furthermore, it confirms and extends the geographic range of PMMoV as an effective tool for monitoring domestic wastewater pollution.

Eu3+ amidst ionic copper in glass: Enhancement through energy transfer from Cu+, or quenching by Cu2+?

A barium-phosphate glass system doped with europium(III) and containing a high concentration of copper(I) together with a copper(II) remnant has been studied spectroscopically. The main object is to elucidate whether the orange-red emission of Eu³⁺ ions succeeds through sensitization via luminescent Cu⁺ ions or else is preferentially quenched by non-radiative transfer to Cu²⁺. A characterization of the melt-quenched glass was first performed by UV/Vis optical absorption, ³¹P nuclear magnetic resonance and infrared absorption spectroscopy. A photoluminescence (PL) spectroscopy and emission decay dynamics assessment was subsequently performed. Despite the concentration of Cu⁺ being estimated to be much higher than that of Cu²⁺, the data shows that quenching of Eu³⁺ PL by Cu²⁺ dominates. The lifetime analysis of emitting centers Cu⁺ and Eu³⁺ points to the origin of the manifestation being that the Eu³⁺→Cu²⁺ non-radiative transfer rate responsible for the quenching is almost two times higher than that for the Cu⁺→Eu³⁺ transfer accountable for the enhancement. Finally, an effort was made for the determination of Cu²⁺ in the glass containing Cu⁺, Cu²⁺ and Eu³⁺ ions based on the Eu³⁺ (⁵D₀) emission decay rates. It was found to be in excellent agreement with the UV/Vis spectrophotometric approach, thus supporting the utility of Eu³⁺ ions for optical sensing of copper(II) in the solid state.

Photoluminescence of Eu³⁺-doped glasses with Cu²⁺ impurities

Glasses activated with Eu(3+) ions are attractive as luminescent materials for various photonic applications. Co-doping with copper has been proposed for enhancing material optical properties, but the quenching effect of Cu(2+) impurities on Eu(3+) emission in glass remains largely unexplored. In this work, Eu2O3/CuO-containing barium-phosphate glasses have been prepared by the melt-quench method, and the Eu(3+) photoluminescence (PL) quenching resulting from Eu(3+)→Cu(2+) energy transfer was evaluated. Optical absorption spectroscopy showed that with the increase in CuO concentration the Cu(2+) absorption band resonant with Eu(3+) emission (e.g. (5)D0→(7)F2 transition around 615 nm) developed steadily. As a result, Eu(3+) PL was progressively quenched. Evaluation of the quenching constants as a function of temperature in the 298-673K range showed differences basically within experimental error, consistent with a resonant transfer and lack of phonon-assisted processes. Moreover, analysis of the Eu(3+) emission decay dynamics revealed a strong correlation between the decay rates and Cu(2+) impurity levels. Results imply that for practical applications the levels of Cu(2+) in Eu(3+)/Cu(+)-activated glasses should be reduced if not removed as these will significantly limit device efficiency.

UV Emission of Gd³⁺ in the Presence of Cu²⁺ : Towards Luminescence Quenching through Quantum Cutting?

The first investigation into the ultraviolet (UV) photoluminescence of gadolinium(III) in the presence of copper(II) is reported. A melt-quenched barium phosphate glass was used as a model matrix. The optical spectroscopy assessment shows that with increasing CuO concentration the Cu(2+) absorption band grows steadily, whereas the UV emission from Gd(3+) ions is progressively quenched. The data, thus, suggests the existence of a Gd(3+) →Cu(2+) energy-transfer process ocurring through quantum cutting. A downconversion/cross-relaxation pathway proceeding through a virtual state in Gd(3+) is proposed. These findings suggest gadolinium(III) could potentially be used in the optical sensing of copper(II).

Kinetics of copper nanoparticle precipitation in phosphate glass: an isothermal plasmonic approach

The kinetics of copper nanoparticle (NP) precipitation in melt-quenched barium-phosphate glass has been studied by in situ isothermal optical micro-spectroscopy. A spectroscopically based approximation technique is proposed to obtain information about the activation energies of nucleation and growth in a narrow temperature range (530-570 °C). Pre-plasmonic and plasmonic NP precipitation stages are identified separated in time. The process as a whole is discussed employing classical nucleation/growth theory and the Kolmogorov-Johnson-Mehl-Avrami phase change model. Activation energies of 3.9(7) eV and 2.6(5) eV have been estimated for the pre-plasmonic and plasmonic spectroscopically assessed stages, respectively. High resolution transmission electron microscopy, differential scanning calorimetry, and Raman spectroscopy were used as complementary techniques for studying the nanoparticulate phase and glass host structure. An empirical linear dependence of the diffusion activation energy on the glass transition temperature with broad applicability is suggested.

The large penumbra: long-distance effects of artificial beach nourishment on Posidonia oceanica meadows

We used modelling and field approaches to assess the influence of beach nourishment on a relatively distant Posidonia oceanica seagrass meadow in the NW Mediterranean. Both sediment transport models and in situ observations showed that, two years after the nourishment and under wave climates prevalent during the study period, sediment movement was restricted to shallow waters (<7 m), above meadow shallow limit. The only significant impact on seagrass meadows during this period was an increase in fine sediments, associated with vertical rhizome growth rates 1.5-1.7 times higher than normal. However, running the model with data of wave climate over several decades indicates that strong storms able to transfer these sediments much deeper, potentially burying meadows, occur with a return period of about 25 years. Taken together, our results suggest that beach nourishment could result in significant sub-lethal and lethal consequences for seagrasses that may go unnoticed with short-term evaluations.

Influence of Ag nanoparticles on the luminescence dynamics of Dy3+ ions in glass: the "plasmonic diluent" effect

This work demonstrates that metallic nanoparticles (NPs) embedded in rare-earth (RE) co-doped dielectrics are able to produce an effect analogous to a reduction in the effective concentration of the luminescent RE ions in the matrix, herein coined the "plasmonic diluent" effect. This has been revealed explicitly for Dy(3+) and Ag NP co-doped aluminophosphate glasses, which were investigated using optical absorption and photoluminescence (PL) spectroscopy with emphasis on the influence of plasmonic NPs on the luminescence decay dynamics of Dy(3+) ions. The glasses were prepared using the melt-quenching technique, where the precipitation of Ag NPs was subsequently induced by heat treatment (HT). The development of the surface plasmon resonance (SPR) band of Ag NPs at around 410 nm resulted in the quenching of Dy(3+) emission for the (4)F9/2 → (6)H15/2, (6)H13/2 transitions (484, 574 nm) under resonant excitation of (6)H15/2 → (4)I15/2 transition at 450 nm. The decay of the (4)F9/2 excited state was monitored at 574 nm (away from SPR) under excitation at 450 nm (within SPR), where the PL dynamics indicated the presence of two populations of Dy(3+) ions in the glasses, in connection with slow (τs) and fast (τf) lifetime components. A tendency of the decay times to increase gradually with HT holding time was observed as the volume fraction of the plasmonic Ag particles increased. The data are interpreted in terms of an ion-to-particle excitation energy transfer operating via surface plasmons in the nanoscale metal. This produces a Dy(3+) deactivation effect analogous to a lowering in the effective concentration of emitting Dy(3+) ions in the matrix, i.e., the metal NPs play a role as a "plasmonic diluent" in the glass system with respect to the luminescent RE ions.

Neural correlates of emotional recognition memory in schizophrenia: effects of valence and arousal

Schizophrenia patients are often impaired in their memory for emotional events compared with healthy subjects. Investigations of the neural correlates of emotional memory in schizophrenia patients are scarce in the literature. The present study aimed to compare cerebral activations in schizophrenia patients and healthy controls during memory retrieval of emotional images that varied in both valence and arousal. In a study with functional magnetic resonance imaging, 37 schizophrenia patients were compared with 37 healthy participants while performing a yes/no recognition paradigm with positive, negative (differing in arousal intensity) and neutral images. Schizophrenia patients performed worse than healthy controls in all experimental conditions. They showed less cerebral activation in limbic and prefrontal regions than controls during retrieval of negatively valenced stimuli, but had a similar pattern of brain activation compared with controls during retrieval of positively valenced stimuli (particularly in the high arousal condition) in the cerebellum, temporal lobe and prefrontal cortex. Both groups demonstrated increased brain activations in the high relative to low arousing conditions. Our results suggest atypical brain function during retrieval of negative pictures, but intact functional circuitry of positive affect during episodic memory retrieval in schizophrenia patients. The arousal data revealed that schizophrenia patients closely resemble the control group at both the behavioral and neurofunctional level.

Integrated data analysis at TJ-II: the density profile

An integrated data analysis system based on Bayesian inference has been developed for the TJ-II stellarator. It reconstructs the electron density profile at a single time point, using data from interferometry, reflectometry, Thomson scattering, and the Helium beam, while providing a detailed error analysis. In this work, we present a novel analysis of the ambiguity inherent in profile reconstruction from reflectometry and show how the integrated data analysis approach elegantly resolves it. Several examples of the application of the technique are provided, in both low-density discharges with and without electrode biasing, and in high-density discharges with an (L-H) confinement transition.

In situ optical microspectroscopy approach for the study of metal transport in dielectrics via temperature- and time-dependent plasmonics: Ag nanoparticles in SiO2 films

This study proposes in situ optical microspectroscopy as a means for the investigation of particle growth and metal transport in nanocomposite systems based on the temperature- and time-dependent optical response of the material. The technique has been successfully employed for the real-time monitoring of the growth of Ag nanoparticles (NPs) in SiO(2) films deposited on soda-lime glass during thermal processing in nitrogen atmosphere. By fitting the surface plasmon resonance (SPR) profiles with spectra calculated by Mie theory in the quasi-static regime, the time variation in effective Ag particle size was determined and subsequently analyzed in the context of crystal growth theory. The Ag NPs were indicated to grow first through a diffusion-based process and subsequently via Ostwald ripening. The experimental determination of the activation energies associated with each one of the particle growth mechanisms was carried out based on the time evolution of the SPR of Ag NPs. Arrhenius-type analyses of a set of time-dependent isotherms allowed for estimating the activation energies at 2.3 eV for the diffusion-based growth and 2.8 eV for the ripening stage.

Real-time monitoring of plasmonic evolution in thick Ag:SiO(2) films: nanocomposite optical tuning

An in situ optical microspectroscopy study of the surface plasmon resonance (SPR) evolution of Ag nanoparticles (NPs) embedded in thick SiO(2) films deposited on soda-lime glass has been conducted during thermal processing in air. The temperature and time dependences of the SPR were analyzed in the context of Mie extinction and crystal growth theories and were discussed along with consideration of oxidation processes and film/substrate physicochemical interactions. At relatively high temperatures, Ag NPs were indicated to grow first through a diffusion-based process and subsequently via Ostwald ripening. At lower temperatures, an initial decrease in Ag particle size was indicated due to oxidation, followed by NP diffusion-based growth. The growth and oxidation stages appeared temperature and time dependent, allowing for the tuning of material properties. The product of Ag NP oxidation was revealed by photoluminescence spectroscopy performed ex situ as single Ag(+) ions. The oxidative effect of the air atmosphere on Ag NPs was shown to be ultimately circumvented by the thick nanocomposite film. The phenomenon was explained on the basis of the displacement of the Ag/Ag(+) redox equilibrium toward Ag NP stability after ion migration toward the substrate being self-constrained. In addition, the current spectroscopic approach has been proposed for estimating the activation energy for silver diffusion in the SiO(2) matrix.

Disturbed sexual dimorphism of brain activation during mental rotation in schizophrenia

BACKGROUND

Sex differences in visuo-spatial abilities have been well documented in the general population, but there are only a few inconsistent reports in schizophrenia. The purpose of the present study was to examine potential sex differences in performance and pattern of brain activations during mental rotation in schizophrenia patients relative to control participants.

METHODS

Thirty three schizophrenia patients (17 women and 16 men) were compared to thirty five healthy control participants (17 women and 18 men), while performing a classic mental rotation task (3-D figures). Blood oxygen level dependent (BOLD) echo-planar images were acquired on a 3-Tesla Siemens TRIO system. Random-effect analyses were performed using SPM5 (UK Wellcome Institute).

RESULTS

Behavioural data revealed a diagnosis-by-sex interaction with healthy men (HM) performing significantly better than schizophrenia men (SZ-M) and no significant difference between healthy women (HW) and schizophrenia women (SZ-W). fMRI results revealed an overall similar pattern of extensive cerebral activations (in the parietal and lateral prefrontal cortex) and deactivations (in the medial prefrontal cortex) in HM and SZ-W during performance of the mental rotation versus control task. In contrast, both HW and SZ-M showed much more restricted activations and no significant deactivations.

CONCLUSIONS

Sex differences in performance and cerebral activations during mental rotation in schizophrenia patients deviated significantly from what we observed in healthy volunteers. This finding supports and extends existing evidence of a disturbed sexual dimorphism in schizophrenia. Moreover, the results emphasize the importance of including both sexes in neurocognitive and neuroimaging studies of schizophrenia.

GPCA vs. PCA in recognition and 3-D localization of ultrasound reflectors

In this paper, a new method of classification and localization of reflectors, using the time-of-flight (TOF) data obtained from ultrasonic transducers, is presented. The method of classification and localization is based on Generalized Principal Component Analysis (GPCA) applied to the TOF values obtained from a sensor that contains four ultrasound emitters and 16 receivers. Since PCA works with vectorized representations of TOF, it does not take into account the spatial locality of receivers. The GPCA works with two-dimensional representations of TOF, taking into account information on the spatial position of the receivers. This report includes a detailed description of the method of classification and localization and the results of achieved tests with three types of reflectors in 3-D environments: planes, edges, and corners. The results in terms of processing time, classification and localization were very satisfactory for the reflectors located in the range of 50-350 cm.

Alternative sensor system and MLP neural network for vehicle pedal activity estimation

It is accepted that the activity of the vehicle pedals (i.e., throttle, brake, clutch) reflects the driver’s behavior, which is at least partially related to the fuel consumption and vehicle pollutant emissions. This paper presents a solution to estimate the driver activity regardless of the type, model, and year of fabrication of the vehicle. The solution is based on an alternative sensor system (regime engine, vehicle speed, frontal inclination and linear acceleration) that reflects the activity of the pedals in an indirect way, to estimate that activity by means of a multilayer perceptron neural network with a single hidden layer.

Antitumor activity of Ad-IU2, a prostate-specific replication-competent adenovirus encoding the apoptosis inducer, TRAIL

In this study, we investigated the preclinical utility and antitumor efficacy of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) delivered by Ad-IU2, a prostate-specific replication-competent adenovirus (PSRCA), against androgen-independent prostate cancer. Through transcriptional control of adenoviral early genes E1a, E1b and E4, as well as TRAIL by two bidirectional prostate-specific enhancing sequences (PSES), expression of TRAIL as well adenoviral replication was limited to prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA)-positive cells. Ad-IU2 induced 5-fold greater apoptosis selectively in PSA/PSMA-positive CWR22rv and C4-2 cells than an oncolytic adenoviral control. Furthermore, prolonged infection with Ad-IU2 reversed TRAIL resistance in LNCaP cells. Ad-IU2 exhibited superior killing efficiency in PSA/PSMA-positive prostate cancer cells at doses 5- to 8-fold lower than required by a PSRCA to produce a similar effect. This cytotoxic effect was not observed in non-prostatic cells, however. As an enhancement of its therapeutic efficacy, Ad-IU2 exerted a TRAIL-mediated bystander effect through direct cell-to-cell contact and soluble factors such as apoptotic bodies. In vivo, Ad-IU2 markedly suppressed the growth of subcutaneous androgen-independent CWR22rv xenografts compared to a PSRCA at six weeks post-treatment (3.1- vs. 17.1-fold growth of tumor). This study demonstrates the potential clinical utility of a PSRCA armed with an apoptosis-inducing ligand.

Seasonal evolution of beach waste and litter during the bathing season on the Catalan coast

Beach waste and litter composition and evolution on popular urban (located in the main nucleus of the municipality) and urbanized (located in residential areas outside the main nucleus) beaches of the Costa Brava (Catalan coast) were assessed during the bathing season. Waste and litter production (amount and composition) were affected by urbanization and varied during the summer. Urban beaches had higher densities of waste deposition and lower percentages of organic, domestic and other miscellaneous waste than urbanized beaches. Litter characteristics were also influenced by type of beach, and varied during the season as a consequence of beach use and cleaning practices, but not environmental factors. Urbanized beaches obtained higher scores for aesthetic quality of sand than urban beaches, and small-sized litter tended to accumulate during the season in the beach of Lloret Centre. The most important problems are management of recyclable materials, litter left by users on the sand, and separation of sand from litter. In addition, current efficiency of mechanical cleaning is low, especially in the withdrawal of cigarette butts. These analyses highlight problems that should be addressed in future management of area beaches.

[Anesthetic management of sacroiliac-vertebral echinococcosis]

Bone echinococcosis affects the spine and pelvis in 60% of cases. Bone lesions may be silent for between 10 and 20 years. The capsules progress aggressively through the medullary canal and replace the trabecular bone without forming cysts, as occurs in the organs, thus making anaplylaxis rare. The combination of chemotherapy and surgery facilitates anesthetic management and reduces the incidence of anaphylactic events and disease recurrence.

Comments on "An accelerated learning algorithm for multilayer perceptrons: optimization layer by layer"

This letter analyzes the performance of the neural network training method known as optimization layer by layer. We show, from theoretical considerations, that the amount of work required with OLL-Learning scales as the third power of the network size, compared with the square of the network size for commonly used conjugate gradient training algorithms. This theoretical estimate is confirmed through a practical example. Thus, although OLL is shown to function very well for small neural networks (less than about 500 weights per layer), it is slower than CG for large neural networks. Second, we show that OLL does not always improve on the accuracy that can be obtained with CG. It seems that the final accuracy that can be obtained depends strongly on the initial network weights.

Use and occupation of Olinda littoral (NE, Brazil): guidelines for an integrated coastal management

Located on the northeast Brazilian coast, Olinda is one of UNESCO's World Heritage Sites, which is economically dependent on tourism, commerce, industry, and the informal economy. Despite its environmental and socioeconomic importance, the city of Olinda (understanding the coast as part of it) has suffered several environmental and human disturbances over the last decades. This work describes the environmental and social status of Olinda's beaches and makes recommendations concerning the development of an Integrated Coastal Management Plan for this coastal zone of the Brazilian littoral. The methodology adopted in this study is based on field campaigns (social, physical, chemical, and biological data collection), local observations, and the collection of sea contention building project data from city hall. The results showed that along the seven studied beaches, the main problems were related to the: (i) building of coastal protections, (ii) inefficient sewage disposal systems, (iii) inefficient urban management, and (iv) natural events (equinoctial spring tides and precipitation/evaporation rates). Casa Caiada beach showed the best hydrologic conditions as a consequence of its morphology and it presents facilities that attract housing and recreation investments (by private and public sectors) valuing and improving local use conditions. The obtained data showed that the studied beaches need an urgent action plan to minimize the environmental degradation of Olinda's littoral and to promote sustainable development of the local coastal environments.

Prophylaxis versus pre-emptive treatment for infective and inflammatory complications of surgical third molar removal: a randomized, double-blind, placebo-controlled, clinical trial with sustained release amoxicillin/clavulanic acid (1000/62.5 mg)

The most common complications after surgical extraction of the third mandibular molar are trismus, oedema or swelling, local pain, dysphagia and infection. The aim of this comparative, double-blind, randomized clinical trial was to evaluate the efficacy of two sustained release amoxicillin/clavulanate regimens in the reduction of infection after third molar extractive surgery. A total of 225 patients were randomized into three equal groups: placebo, prophylaxis with single pre-surgical dose of two tablets amoxicillin/clavulanate 1000/62.5 mg, and pre-emptive post-surgery therapy with two tablets amoxicillin/clavulanate 1000/62.5 mg BID for 5 days. A higher rate of infection (P=0.006) was found among patients receiving placebo (16%) than those receiving single-dose prophylaxis (5.3%) or 5-day pre-emptive therapy (2.7%). A relationship between both the duration (13.8% for long versus 7.4% for medium versus 1.6% for short) and difficulty (12.7% with ostectomy versus 3.5% without ostectomy; P=0.011) of surgical procedure and incidence of subsequent infection was also observed. Both prophylactic and therapeutic regimens versus placebo achieved greater reduction of pain after surgery on day 3 (P=0.001). Logistic regression analysis revealed a risk of infection of 24%, 9% and 4% for ostectomy with placebo, prophylaxis and pre-emptive treatment, respectively, whereas it was 7%, 2% and 1% if ostectomy was not performed. Pre-emptive therapy with the oral sustained release amoxicillin/clavulanate formulation reduced the rate of subsequent infection in patients undergoing ostectomy. Prophylaxis was beneficial in simpler procedures and may be indicated in cases where ostectomy is not performed.

Topoisomerase I-mediated DNA cleavage as a guide to the development of antitumor agents derived from the marine alkaloid lamellarin D: triester derivatives incorporating amino acid residues

The marine alkaloid lamellarin D (LAM-D) has been recently characterized as a potent poison of human topoisomerase I endowed with remarkable cytotoxic activities against tumor cells. We report here the first structure-activity relationship study in the LAM-D series. Two groups of triester compounds incorporating various substituents on the three phenolic OH at positions 8, 14 and 20 of 6H-[1]benzopyrano[4',3':4,5]pyrrolo[2,1-a]isoquinolin-6-one pentacyclic planar chromophore typical of the parent alkaloid were tested as topoisomerase I inhibitors. The non-amino compounds in group A showed no activity against topoisomerase I and were essentially non cytotoxic. In sharp contrast, compounds in group B incorporating amino acid residues strongly promoted DNA cleavage by human topoisomerase I. LAM-D derivatives tri-substituted with leucine, valine, proline, phenylalanine or alanine residues, or a related amino side chain, stabilize topoisomerase I-DNA complexes. The DNA cleavage sites detected at T downward arrow G or C downward arrow G dinucleotides with these molecules were identical to that of LAM-D but slightly different from those seen with camptothecin which stimulates topoisomerase I-mediated cleavage at T downward arrow G only. In the DNA relaxation and cleavage assays, the corresponding Boc-protected compounds and the analogues of the non-planar LAM-501 derivative lacking the 5-6 double bond in the quinoline B-ring showed no effect on topoisomerase I and were considerably less cytotoxic than the corresponding cationic compounds in the LAM-D series. The presence of positive charges on the molecules enhances DNA interaction but melting temperature studies indicate that DNA binding is not correlated with topoisomerase I inhibition or cytotoxicity. Cell growth inhibition by the 41 lamellarin derivatives was evaluated with a panel of tumor cells lines. With prostate (DU-145 and LN-CaP), ovarian (IGROV and IGROV-ET resistant to ecteinascidin-743) and colon (LoVo and LoVo-Dox cells resistant to doxorubicin) cancer cells (but not with HT29 colon carcinoma cells), the most cytotoxic compounds correspond to the most potent topoisomerase I poisons. The observed correlation between cytotoxicity and topoisomerase I inhibition strongly suggests that topoisomerase I-mediated DNA cleavage assays can be used as a guide to the development of superior analogues in this series. LAM-D is the lead compound of a new promising family of antitumor agents targeting topoisomerase I and the amino acid derivatives appear to be excellent candidates for a preclinical development.

Fixed-dose low-molecular-weight heparin for secondary prevention of venous thromboembolism in patients with disseminated cancer: a prospective cohort study

INTRODUCTION

Secondary prevention of venous thromboembolism (VTE) with vitamin K antagonists is often problematic in patients with cancer. We prospectively evaluated the effectiveness and safety of long-term subcutaneous dalteparin in a series of consecutive patients with symptomatic VTE and metastatic cancer.

PATIENTS AND METHODS

The study included 203 patients, aged 36-96 years. The initial treatment consisted of a 7-day course of subcutaneous dalteparin according to body weight. Then, patients received a fixed dose of 10 000 IU dalteparin once daily for at least 3 months. In patients developing transient thrombocytopenia the dose was reduced to 5000 IU daily while the platelet count remained <50,000; and to 2500 IU daily while it remained <10 000. Patients undergoing any surgical intervention during the study were put on 5000 IU daily during the first 4 days, switching thereafter to 10,000 IU. Patients undergoing any other invasive procedure (i.e. biopsies, punctures) received a 5000 IU dose the same day, instead of 10 000 IU.

RESULTS

Eleven patients (5.4%) developed major bleeding complications (6 fatal) during the 3-month study period, and 18 patients (8.9%) developed VTE recurrences (2 patients died). There were no higher complication rates in patients with either liver or brain metastases, nor during thrombocytopenia, surgery or invasive procedures.

CONCLUSIONS

Fixed dose 10,000 IU subcutaneous dalteparin once daily for 3 months was not associated with more complications in patients with liver or brain metastases. The dose adjustment for patients with thrombocytopenia, surgery or invasive procedures was safe too.