Detection of bacterial spores with lanthanide-macrocycle binary complexes

The detection of bacterial spores via dipicolinate-triggered lanthanide luminescence has been improved in terms of detection limit, stability, and susceptibility to interferents by use of lanthanide−macrocycle binary complexes. Specifically, we compared the effectiveness of Sm, Eu, Tb, and Dy complexes with the macrocycle 1,4,7,10-tetraazacyclododecane-1,7-diacetate (DO2A) to the corresponding lanthanide aquo ions. The Ln(DO2A)^+ binary complexes bind dipicolinic acid (DPA), a major constituent of bacterial spores, with greater affinity and demonstrate significant improvement in bacterial spore detection. Of the four luminescent lanthanides studied, the terbium complex exhibits the greatest dipicolinate binding affinity (100-fold greater than Tb^(3+) alone, and 10-fold greater than other Ln(DO2A)^+ complexes) and highest quantum yield. Moreover, the inclusion of DO2A extends the pH range over which Tb−DPA coordination is stable, reduces the interference of calcium ions nearly 5-fold, and mitigates phosphate interference 1000-fold compared to free terbium alone. In addition, detection of Bacillus atrophaeus bacterial spores was improved by the use of Tb(DO2A)^+, yielding a 3-fold increase in the signal-to-noise ratio over Tb^(3+). Out of the eight cases investigated, the Tb(DO2A)^+ binary complex is best for the detection of bacterial spores

BALLET: Balloon Locomotion for Extreme Terrain

This report documents the work performed in our investigation into the BALLET (Balloon Locomotion for Extreme Terrain) concept. We focused on four areas in this Phase I effort. They were 1) identifying the science targets and objectives with the corresponding requisite instrumentation and operational capabilities that could be achieved with a BALLET mission, 2) developing an architecture for the deployment and operation of this concept for a future mission to a planetary body, 3) analyzing a parametric physical model of BALLET under the environmental conditions of Mars, Titan and Earth to determine its feasibility, and 4) developing and demonstrating coordinated control of the BALLET mobility system to enable locomotion over rugged terrain. The results of our investigations in these focus areas are documented in the following sections. A paper summarizing the preliminary results from this study has been accepted for publication and presentation at the 2019 IEEE Aerospace Conference [Nayar, 2019]

A co-crystal between benzene and ethane: a potential evaporite material for Saturn’s moon Titan

Using synchrotron X-ray powder diffraction, the structure of a co-crystal between benzene and ethane formed in situ at cryogenic conditions has been determined, and validated using dispersion-corrected density functional theory calculations. The structure comprises a lattice of benzene molecules hosting ethane molecules within channels. Similarity between the intermolecular interactions found in the co-crystal and in pure benzene indicate that the C— H network of benzene is maintained in the co-crystal, however, this expands to accommodate the guest ethane molecules. The co-crystal has a 3:1 benzene:ethane stoichiometry and is described in the space group R3 with a = 15.977 (1) A˚ and c = 5.581 (1) A˚ at 90 K, with a density of 1.067 g cm3 . The conditions under which this co-crystal forms identify it is a potential that forms from evaporation of Saturn’s moon Titan’s lakes, an evaporite material

Bacterial Spore Detection by [Tb^(3+)(macrocycle)(dipicolinate)] Luminescence

Dipicolinic acid (DPA) is a unique constituent of bacterial spores, a dormant form of Bacillus and Clostridium, which can be detected using DPA-triggered Tb^(3+) luminescence. [Tb(DO2A)]^+ improves the sensitivity of bacterial spore detection over Tb^(3+)(aq) owing to the exclusion of coordinated water molecules and represents the first step toward construction of a DPA receptor site with enhanced binding selectivity. The title ternary [Tb(DO2A)(DPA)]- complex was structurally characterized and features two DO2A-DPA interligand hydrogen interactions that stabilize the complex

The support and information needs of adolescents and young adults with cancer when active treatment ends

Background: The end of active treatment is a period of high stress for young people with cancer, but limited literature exists about their information and support needs during this phase. This study aimed to understand the needs of young people with cancer, how these needs are currently being met, and how best to provide information and support at the end of active treatment. Methods: This was a multi-stage, mixed methods study exploring the end of treatment experience from the perspectives of young people, and the healthcare professionals caring for them. Semi-structured interviews were undertaken with healthcare professionals, which informed a survey administered nationally. Subsequently, semi-structured interviews were conducted with young people. These combined results informed a co-design workshop to develop recommendations. Results: Telephone interviews were conducted with 12 healthcare professionals and 49 completed the online survey. A total of 11 young people aged 19–26 years (female = 8; 73%) were interviewed. The stakeholder workshop was attended by both healthcare professionals (n = 8) and young people (n = 3). At the end of treatment young people experience numerous ongoing physical issues including pain, fatigue and insomnia; in addition to a range of psychosocial and emotional issues including anxiety, fear of recurrence and isolation. The top three priorities for end of treatment care were: earlier provision and preparation around on-going impact of cancer and cancer treatment; standardised and continued follow-up of young people’s emotional well-being; and development of more information and resources specific to young people. Conclusion The access and availability of appropriate information and sources of support at the end of treatment is variable and inequitable. Young people’s needs would be more effectively met by timely, structured and accessible information, and support provision at the end of treatment to both prepare and enable adaptation across their transition to living with and beyond cancer. This will require both organisational and practical adjustments in care delivery, in addition to a renewed and updated understanding of what the ‘end of treatment’ transition process means

Terbium-Macrocycle Complexes as Chemical Sensors: Detection of an Aspirin Metabolite in Urine Using a Salicylurate-Specific Receptor Site

Salicylurate (SU) is the major metabolite in urine of acetylsalicylic acid (aspirin) and can be used as a metric to monitor aspirin pharmacokinetics and as an indicator of appendicitis, anemia, and liver disease. Detection in urine and plasma currently requires solvent extraction or other sample handling prior to analysis. We present a simple method to quantify SU in urine via chelation to a terbium binary complex with the macrocycle 1,4,7,10-tetraazacyclododecane-1,7-bisacetate (DO2A). Binding of SU to form the [Tb(DO2A)(SU)]− ternary complex triggers intense luminescence under UV excitation due to an absorbance-energy transfer-emission mechanism. Here we report characterization of the [Tb(DO2A)(SU)]− ternary complex and application of this sensitized lanthanide luminescence method to quantify SU in urine samples following a low-dose aspirin regimen