Selective Gold Precipitation by a Tertiary Diamide Driven by Thermodynamic Control

The simple diamide ligand L was previously shown to selectively precipitate gold from acidic solutions typical of e-waste leach streams, with precipitation of gallium, iron, tin, and platinum possible under more forcing conditions. Herein, we report direct competition experiments to afford the order of selectivity. Thermal analysis indicates that the gold-, gallium-, and iron-containing precipitates present as the most thermodynamically stable structures at room temperature, while the tin-containing structure does not. Computational modeling established that the precipitation process is thermodynamically driven, with ion exchange calculations matching the observed experimental selectivity ordering. Calculations also show that the stretched ligand conformation seen in the X-ray crystal structure of the gold-containing precipitate is more strained than in the structures of the other metal precipitates, indicating that intermolecular interactions likely dictate the selectivity ordering. This was confirmed through a combination of Hirshfeld, noncovalent interaction (NCI), and quantum theory of atoms in molecules (QTAIM) analyses, which highlight favorable halogen···halogen contacts between metalates and pseudo-anagostic C-H···metal interactions in the crystal structure of the gold-containing precipitate.

Discovery and Characterization of a Bicyclic Peptide (Bicycle) Binder to Thymic Stromal Lymphopoietin

Thymic stromal lymphopoietin (TSLP) is an epithelial-derived pro-inflammatory cytokine involved in the development of asthma and other atopic diseases. We used Bicycle Therapeutics' proprietary phage display platform to identify bicyclic peptides (Bicycles) with high affinity for TSLP, a target that is difficult to drug with conventional small molecules due to the extended protein-protein interactions it forms with both receptors. The hit series was shown to bind to TSLP in a hotspot, that is also used by IL-7Rα. Guided by the first X-ray crystal structure of a small peptide binding to TSLP and the identification of key metabolites, we were able to improve the proteolytic stability of this series in lung S9 fractions without sacrificing binding affinity. This resulted in the potent Bicycle 46 with nanomolar affinity to TSLP (KD = 13 nM), low plasma clearance of 6.4 mL/min/kg, and an effective half-life of 46 min after intravenous dosing to rats.

Family listening/circle program: The experience of community action projects to promote family and community wellness in three tribal communities in New Mexico

Introduction

The Family Listening/Circle Program (FLCP) is a community-based participatory research (CBPR), culture-centered, intergenerational family strengthening program that was co-developed in partnership with the University of New Mexico's Center for Participatory Research (UNM-CPR) and three tribal communities (Pueblo of Jemez, Ramah Navajo, and Mescalero Apache) in New Mexico. The Family Listening/Circle Program brings together fourth and fifth graders, their parents, caregivers, and elders to reduce risky behaviors associated with the initiation of substance use among the youth, and to strengthen family communication and connectedness to culture and language as protective factors.

Methods

The tribal research teams (TRTs) from each community worked with UNM-CPR to co-create, pilot, implement, and evaluate the tribally-specific FL/CP curricula centered in their own tribal histories, language, knowledge, visions, and actions for the future. A key component of the FL/CP involved the planning and completion of community action projects (CAPs) by participating families. During the final session of the program, the families present their community action projects on poster boards, with children leading the presentations. The TRTs and UNM team document narratives of what was shared and learned by the families.

Results

The CAPs provide an empowerment and community benefit focus based on Paulo Freire's philosophy that people can become agents of change if they identify and work on issues that are important to them. The community action projects are also centered in Indigenous values and practices of reciprocity, responsibility, and being active members of the community.

Discussion

The CAPs added unique contributions to the Family Listening/Circle Program as the participants' learnings were strengthened when they had the opportunity to give back to their communities. The CAPs were important to document as they illustrated the potential range of effectiveness with their capacity to empower participants to address challenges within their communities, strengthen cultural norms and values, and improve the wellbeing of community members.

Investigating the hydration of C3A in the presence of the potentially toxic element chromium-a route to remediation?

Pollution by hexavalent chromium is a growing, global problem. Its presence in public water systems is often the result of industrial activities, both past and present. In this study, tricalcium aluminate (C3A, Ca₃Al₂O₆) is added to solutions of varying concentrations of potassium chromate (K₂CrO₄) and samples of both the solid and liquid are taken at various time intervals to monitor the removal of chromium from the solutions. Solution concentrations of 0.2 M, 0.1 M, 0.02 M, and 0.01 M are used, and the chromium concentration is found to reduce in all cases. For the 0.02 M solution the chromium concentration is reduced from 1040 ppm to 3.1 ppm in 1 week, and the chromium concentration of the 0.01 M solution is reduced from 520 ppm to 0.26 ppm in only one day of reaction with the C3A. The chromium removed from solution is identified in the solid products, which were fully characterised as being a mixture of ettringite (Ca₆[Al(OH)₆]₂(CrO₄)₃·26H₂O) and monochromate (Ca₄[Al(OH)₆]₂CrO₄·8H₂O) phases from analysis of Powder X-ray Diffraction and Fourier Transform Infrared Spectroscopy data. The work presented here is a proof of concept study to investigate C3A as a potential material for the removal of hexavalent chromium from solution. The results from this study are initial steps towards development of this as a technology for hexavalent chromium remediation.

A calcium aluminate material has been successfully used to remove toxic hexavalent chromium from water. A thorough powder X-ray diffraction study was done to determine the composition of the products.

Discovery by Virtual Screening of an Inhibitor of CDK5-Mediated PPARγ Phosphorylation

Thiazolidinedione PPARγ agonists such as rosiglitazone and pioglitazone are effective antidiabetic drugs, but side effects have limited their use. It has been posited that their positive antidiabetic effects are mainly mediated by the inhibition of the CDK5-mediated Ser273 phosphorylation of PPARγ, whereas the side effects are linked to classical PPARγ agonism. Thus compounds that inhibit PPARγ Ser273 phosphorylation but lack classical PPARγ agonism have been sought as safer antidiabetic therapies. Herein we report the discovery by virtual screening of 10, which is a potent PPARγ binder and in vitro inhibitor of the CDK5-mediated phosphorylation of PPARγ Ser273 and displays negligible PPARγ agonism in a reporter gene assay. The pharmacokinetic properties of 10 are compatible with oral dosing, enabling preclinical in vivo testing, and a 7 day treatment demonstrated an improvement in insulin sensitivity in the ob/ob diabetic mouse model.

The gastropod shell has been co-opted to kill parasitic nematodes

Exoskeletons have evolved 18 times independently over 550 MYA and are essential for the success of the Gastropoda. The gastropod shell shows a vast array of different sizes, shapes and structures, and is made of conchiolin and calcium carbonate, which provides protection from predators and extreme environmental conditions. Here, I report that the gastropod shell has another function and has been co-opted as a defense system to encase and kill parasitic nematodes. Upon infection, cells on the inner layer of the shell adhere to the nematode cuticle, swarm over its body and fuse it to the inside of the shell. Shells of wild Cepaea nemoralis, C. hortensis and Cornu aspersum from around the U.K. are heavily infected with several nematode species including Caenorhabditis elegans. By examining conchology collections I show that nematodes are permanently fixed in shells for hundreds of years and that nematode encapsulation is a pleisomorphic trait, prevalent in both the achatinoid and non-achatinoid clades of the Stylommatophora (and slugs and shelled slugs), which diverged 90–130 MYA. Taken together, these results show that the shell also evolved to kill parasitic nematodes and this is the only example of an exoskeleton that has been co-opted as an immune system.

Evaluation and further development of EASE model 2.0

EASE (Estimation and Assessment of Substance Exposure) is a general model that may be used to predict workplace exposure to a wide range of substances hazardous to health. First developed in the early 1990s, it is now in its second Windows version. This paper provides a critical assessment of the utility and performance of the EASE model, and on the basis of this review, recommendations for the structure of a revised model are outlined. Twenty-seven stakeholders were interviewed about their previous use of EASE, perceived advantages and limitations of the model and suggestions for improvement. A subset of stakeholders was contacted on a second occasion to determine their views on the preferred outputs for an ideal exposure assessment model. Overall, stakeholders felt that the model should be updated to provide more accurate and precise exposure assessments. However, users also expressed the view that the simplicity and usability of the software model should not be compromised. Six studies investigating the validity of the inhalation exposure assessment section of EASE were identified. These showed that the model generally either predicted close to the measured exposures or overestimated exposure; though performance was highly variable. Two studies investigated the validity of the dermal exposure assessment and found that EASE produced considerable overestimates of actual dermal exposure (the amount of a substance that actually lands on the skin). A conceptual model of exposure was developed to investigate whether the structure of the EASE model is appropriate. Although EASE has a number of characteristics that describe exposure, it is a greatly simplified model and does not include all the important exposure determinants. More importantly, EASE can produce estimates of exposure that are ambiguous or incomplete. Our conceptual model may provide a rational basis for developing an improved version of EASE but further consultation is needed to decide the purpose and intended use of any successor to EASE.

Chlamydial serologic studies and recurrent spontaneous abortion

OBJECTIVE

Our purpose was to investigate the putative association between immunoglobulin G antibodies to Chlamydia trachomatis and recurrent spontaneous abortions.

STUDY DESIGN

Sera from 106 idiopathic recurrent aborters and 81 of their partners were tested for immunoglobulin G antichlamydial antibodies by whole inclusion immunofluorescence and compared with 3890 sera from a general antenatal population. Positive sera were further investigated by microimmunofluorescence to determine species (Chlamydia trachomatis, Chlamydia pneumoniae, Chlamydia psittaci) specificity.

RESULTS

Twenty-six (24.5%) of women with recurrent spontaneous abortions had immunoglobulin G antichlamydial antibodies compared with 28 (34.6%) of their partners (chi 2 2.25, p < 0.05) and 788 (20.3%) of the general antenatal population (chi 2 1.16, p < 0.05), and the incidence of antibody positivity showed no trend with increasing number of previous abortions. Fourteen women with recurrent spontaneous abortions had antibodies to Chlamydia trachomatis, 12 to Chlamydia pneumoniae. The prevalence of antibodies to C. trachomatis did not differ significantly between women with recurrent spontaneous abortions and their partners, but the male partners had a significantly (p = 0.005) higher prevalence of Chlamydia pneumoniae antibodies. Chlamydial antibody seropositivity did not correlate with subfertility or subsequent pregnancy outcome.

CONCLUSION

There is no association between immunoglobulin G antibodies to Chlamydia trachomatis and recurrent spontaneous abortion.

Evaluation of the Pro-Lab ID ring system for the identification of medically important yeasts

We evaluated 151 coded isolates of medically important yeast species belonging to the genera Candida, Cryptococcus, Geotrichum, Rhodoturula, Saccharomyces and Torulopsis using the newly developed rapid Pro-Lab Identification Ring, PL 960 system (PLID-Ring). All isolates were concurrently identified by the API 20C and conventional procedures comprising macro- and micromorphology, assimilation and fermentation of various carbon and nitrogen compounds. The PLID-Ring system identified isolates of Candida albicans, C. kefyr, C. krusei, C. lusitaniae, C. parapsilosis, Rhodotorula rubra, and Torulopsis glabrata with 100% accuracy in 24 h. This system identified C guilliermondii and S. cerevisiae isolates with an accuracy of 90% and 86%, respectively, while those belonging to Cr. neoformans, T. candida (= C. famata), C. rugosa and C. tropicalis were identified with 38.4%, 50%, 12.5% and 50% accuracy, respectively. Three isolates of Cr. laurentii were not identified by the PLID-Ring system. The overall accuracy of the PLID-Ring system was 81.45% (123 of 151 isolates). However, the system does not include species such as Cr. laurentii in its data base. When these three Cr. laurentii isolates were excluded from the evaluation, the accuracy of the PLID-Ring system increased from 81.45% to 83.1%.

Spectrophotofluorometric and gas-liquid chromatographic methods for the estimation of mexiletine (Kö 1173) in plasma and urine

Methods are presented for the spectrophotofluorometric and gas-liquid chromatographic determination in plasma and urine of the anti-arrhythmic compound, mexiletine (Kö 1173). Both methods involve extraction of the drug from alkaline plasma with ether. In the spectrophotofluorometric method the compound is re-extracted into 0&#x006d;̇05n HCl and emission intensity determined at 300 nm with activation at 228 nm. In the chromatographic method the drug is acylated during evaporation of the ether. Both butyryl and acetyl derivatives could be used. Use of a nitrogen-sensitive detector increased the sensitivity and selectivity of the method and allowed more rapid analyses. There was good agreement between results obtained by spectrophotofluorometric and chromatographic methods.