The pervasive influence of systems of power on transition readiness for adult care in sickle cell disease: A qualitative study.

BACKGROUND: Adolescence and young adulthood are vulnerable developmental periods for individuals with sickle cell disease (SCD), particularly given the impact of social inequities, challenges with transitioning to adult healthcare services, and increased risk for morbidity and mortality. Systems of power, such as institutionalized and interpersonal manifestations of bias, could impact SCD transfer and engagement in adult care through their influence on healthcare transition readiness; yet research in this area is limited. OBJECTIVE: To characterize how systems of power impact transition readiness factors described in the Social-ecological Model of AYA Readiness for Transition to Promote Health Equity (SMART-E) framework at the patient, caregiver, and practitioner levels. METHODS: Pediatric adolescents and young adults (AYA), transferred AYA, caregivers, and practitioners participated in semi-structured focus groups and individual interviews examining health equity and systems of power during healthcare transition. Focus groups/interviews were transcribed and coded using a deductive approach via the updated SMART-E framework. RESULTS: Ten pediatric AYA with SCD, nine transferred AYA with SCD, eight caregivers, and nine practitioners participated in a focus group or interview. Qualitative findings across reporters emphasize the impact of systems of power (e.g., racial bias and disease stigma) on knowledge, skills and self-efficacy, beliefs and expectations, goals and motivation, and emotions and psychosocial functioning at the patient, caregiver, and practitioner levels. CONCLUSION: Systems of power are prevalent with respect to transition barriers for AYA with SCD and their supports. Structural, institutional, and individual factors with potential to reduce the influence of systems of power should be further identified and targeted for intervention.

Direct and indirect estimation of adolescent sexual intercourse and contraceptive use in Rajasthan India: an application of the best friend methodology.

BACKGROUND: Existing estimates of adolescent sexual and reproductive health (ASRH) behaviors may be a gross undercount given the sensitivity of this behavior in Indian culture. The objective of this study was to estimate ASRH behaviors in Rajasthan, India using direct questions and the best friend approach that seeks to reduce social desirability bias. METHODS: We used population-based data of adolescents aged 15-19 in Rajasthan collected between September and December 2022. Data include whether the respondent and her closest female friend ever had a partner, ever had sex, ever used contraception, and were currently using contraception. We estimated respondent and best friend ASRH outcomes separately, overall and among unmarried adolescents for whom we anticipate social desirability bias is greatest. RESULTS: The best friend approach performed well, with method assumptions largely met even before adjustments. Respondent and best friend estimates were similar among all adolescents except for current contraceptive use, which was higher for friends (though not significantly so). However, we observed large differences in ASRH behaviors between unmarried respondents and friends, with a significantly higher percentage of friends who ever had a partner (4.3% respondents, 11.6% friends), and a slightly higher percentage who ever had sex (2.4%, 3.8%) and who were currently using contraception (17.0%, 19.7% among those in need of contraception). CONCLUSIONS: We observed potential benefits of using the best friend methodology in estimating premarital sexual activity, but further work is needed to refine social network-based measures of sensitive adolescent behaviors in larger study samples to better understand ASRH needs.

An in vitro-in silico workflow for predicting renal clearance of PFAS.

Per- and poly-fluoroalkyl substances (PFAS) have a wide range of elimination half-lives (days to years) in humans, thought to be in part due to variation in proximal tubule reabsorption. While human biomonitoring studies provide important data for some PFAS, renal clearance (CLrenal) predictions for hundreds of PFAS in commerce requires experimental studies with in vitro models and physiologically-based in vitro-to-in vivo extrapolation (IVIVE). Options for studying renal proximal tubule pharmacokinetics include cultures of renal proximal tubule epithelial cells (RPTECs) and/or microphysiological systems. This study aimed to compare CLrenal predictions for PFAS using in vitro models of varying complexity (96-well plates, static 24-well Transwells and a fluidic microphysiological model, all using human telomerase reverse transcriptase-immortalized and OAT1-overexpressing RPTECs combined with in silico physiologically-based IVIVE. Three PFAS were tested: one with a long half-life (PFOS) and two with shorter half-lives (PFHxA and PFBS). PFAS were added either individually (5 µM) or as a mixture (2 µM of each substance) for 48 h. Bayesian methods were used to fit concentrations measured in media and cells to a three-compartmental model to obtain the in vitro permeability rates, which were then used as inputs for a physiologically-based IVIVE model to estimate in vivo CLrenal. Our predictions for human CLrenal of PFAS were highly concordant with available values from in vivo human studies. The relative values of CLrenal between slow- and faster-clearance PFAS were most highly concordant between predictions from 2D culture and corresponding in vivo values. However, the predictions from the more complex model (with or without flow) exhibited greater concordance with absolute CLrenal. Overall, we conclude that a combined in vitro-in silico workflow can predict absolute CLrenal values, and effectively distinguish between PFAS with slow and faster clearance, thereby allowing prioritization of PFAS with a greater potential for bioaccumulation in humans.

A qualitative exploration of reproductive coercion experiences and perceptions in four geo-culturally diverse sub-Saharan African settings.

Reproductive coercion (RC) is any intentional behavior that interferes with another's reproductive decision-making or pregnancy outcome. This study aims to qualitatively examine RC experiences and perceptions among women and men in Ethiopia, Nigeria (Kano and Anambra States), and Uganda. This is a secondary analysis utilizing qualitative data from the Women's and Girls' Empowerment in Sexual and Reproductive Health study. Across sites, focus group discussions (38 groups; n=320 participants) and in-depth interviews (n=120) were conducted, recorded, and transcribed. Transcripts were loaded into Atlas.ti, and quotes describing experiences of reproductive control or abuse were coded as "reproductive coercion." RC quotes were input into a matrix for thematic analysis. Emergent RC themes included indirect reproductive pressures, direct family planning interference, concurrent experiences of violence, and responses to RC. Indirect reproductive pressures included tactics to both promote and prevent pregnancy, while direct interference centered on pregnancy promotion. Women who were not compliant with their partners' reproductive demands were often subjected to violence from multiple actors (i.e., parents, in-laws, community members) in addition to their partners. Despite concurrent forms of violence, women across sites resisted RC by using contraceptives covertly, choosing to abort, or leaving their abusive partnerships. Women and men across sites indicated that men were highly influential in fertility. RC behaviors were a mechanism of control over desired reproductive outcomes, which were often rooted in perceptions of childbearing as social status. Findings indicate a need for more nuanced community interventions targeting social norms, as well as improved RC screening and response within health services.

Geographic EBV variants confound disease-specific variant interpretation and predict variable immune therapy responses.

ABSTRACT: Epstein-Barr virus (EBV) is a potent carcinogen linked to hematologic and solid malignancies and causes significant global morbidity and mortality. Therapy using allogeneic EBV-specific lymphocytes shows promise in certain populations, but the impact of EBV genome variation on these strategies remains unexplored. To address this, we sequenced 217 EBV genomes, including hematologic malignancies from Guatemala, Peru, Malawi, and Taiwan, and analyzed them alongside 1307 publicly available EBV genomes from cancer, nonmalignant diseases, and healthy individuals across Africa, Asia, Europe, North America, and South America. These included, to our knowledge, the first natural killer (NK)/T-cell lymphoma (NKTCL) EBV genomes reported outside of East Asia. Our findings indicate that previously proposed EBV genome variants specific to certain cancer types are more closely tied to geographic origin than to cancer histology. This included variants previously reported to be specific to NKTCL but were prevalent in EBV genomes from other cancer types and healthy individuals in East Asia. After controlling for geographic region, we did identify multiple NKTCL-specific variants associated with a 7.8-fold to 21.9-fold increased risk. We also observed frequent variations in EBV genomes that affected peptide sequences previously reported to bind common major histocompatibility complex alleles. Finally, we found several nonsynonymous variants spanning the coding sequences of current vaccine targets BALF4, BKRF2, BLLF1, BXLF2, BZLF1, and BZLF2. These results highlight the need to consider geographic variation in EBV genomes when devising strategies for exploiting adaptive immune responses against EBV-related cancers, ensuring greater global effectiveness and equity in prevention and treatment.

Comparative Analysis of the Physiological and Transport Functions of Various Sources of Renal Proximal Tubule Cells Under Static and Fluidic Conditions in PhysioMimix{trade mark, serif} T12 Platform.

In vitro models that can faithfully replicate critical aspects of kidney tubule function such as directional drug transport are in high demand in pharmacology and toxicology. Accordingly, development and validation of new models is underway. The objective of this study was to characterize physiological and transport functions of various sources of human renal proximal tubule epithelial cells (RPTECs). We tested TERT1-immortalized RPTEC, including OAT1-, OCT2- or OAT3-overexpressing variants, and primary RPTECs. Cells were cultured on transwell membranes in static (24-well transwells) and fluidic (transwells in PhysioMimix{trade mark, serif} T12 organ-on-chip with 2 mL/s flow) conditions. Barrier formation, transport, and gene expression were evaluated. We show that two commercially available primary RPTECs were not suitable for studies of directional transport on transwells because they formed a substandard barrier even though they exhibited higher expression of transporters, especially under flow. TERT1-parent, -OAT1 and -OAT3 cells formed robust barriers, but were unaffected by flow. TERT1-OAT1 cells exhibited inhibitable para-aminohippurate transport, it was enhanced by flow. However, efficient tenofovir secretion and perfluorooctanoic acid reabsorption by TERT1-OAT1 cells were not modulated by flow. Gene expression showed that TERT1 and TERT1-OAT1 cells were most correlated with human kidney than other cell lines, but that flow did not have noticeable effects. Overall, our data show that addition of flow to in vitro studies of the renal proximal tubule may afford benefits in some aspects of modeling kidney function, but that careful consideration of the impact such adaptations would have on the cost and throughput of the experiments is needed. Significance Statement The topic of reproducibility and robustness of the complex microphysiological systems is looming large in the field of biomedical research; therefore, the uptake of these new models by the end-users is slow. This study systematically compared various RPTEC sources and experimental conditions, aiming to identify the level of model complexity needed for testing renal tubule transport. We demonstrate that while tissue chips may afford some benefits, their throughput and complexity need careful consideration in each context of use.

Machine learning approaches delimit cryptic taxa in a previously intractable species complex.

Cryptic species are not diagnosable via morphological criteria, but can be detected through analysis of DNA sequences. A number of methods have been developed for identifying species based on genetic data; however, these methods are prone to over-splitting taxa with extreme population structure, such as dispersal-limited organisms. Machine learning methodologies have the potential to overcome this challenge. Here, we apply such approaches, using a large dataset generated through hybrid target enrichment of ultraconserved elements (UCEs). Our study taxon is the Aoraki denticulata species complex, a lineage of extremely low-dispersal arachnids endemic to the South Island of Aotearoa New Zealand. This group of mite harvesters has been the subject of previous species delimitation studies using smaller datasets generated through Sanger sequencing and analytical approaches that rely on multispecies coalescent models and barcoding gap discovery. Those analyses yielded a number of putative cryptic species that seems unrealistic and extreme, based on what we know about species' geographic ranges and genetic diversity in non-cryptic mite harvesters. We find that machine learning approaches, on the other hand, identify cryptic species with geographic ranges that are similar to those seen in other morphologically diagnosable mite harvesters in Aotearoa New Zealand's South Island. We performed both unsupervised and supervised machine learning analyses, the latter with training data drawn either from animals broadly (vagile and non-vagile) or from a custom training dataset from dispersal-limited harvesters. We conclude that applying machine learning approaches to the analysis of UCE-derived genetic data is an effective method for delimiting species in complexes of low-vagility cryptic species, and that the incorporation of training data from biologically relevant analogues can be critically informative.

Characterizing Family Planning Utilization in Adult Women and Adolescents in Pohnpei, Federerated States of Micronesia.

INTRODUCTION: Increasing family planning xutilization in low-income countries to improve health outcomes of women and children is a global priority. The Federated States of Micronesia (FSM) has poor maternal child health outcomes; therefore, this study aimed to examine family planning utilization in Pohnpei State, FSM. METHODS: This cross-sectional study sought to characterize family planning utilization in adult women of reproductive age and high school age adolescents in Pohnpei using representative survey data collected in 2019 (N = 570 and N = 1726, respectively). Chi-square tests were used to determine significant factors associated with family planning utilization. RESULTS: Among adult women of reproductive age (18-49 years old) not trying to get pregnant, 31.6% reported using contraception during last intercourse. Contraceptive use was significantly lower among younger women (18-24 years old) (21.7%, p = 0.021), unmarried women (18.6%, p < 0.001), those without health insurance (28.7%, p = 0.030), those who have never had a pap smear (20.5%, p < 0.001), and those who have never been pregnant (14.5%, p < 0.002). Among adolescents who reported being sexually active, 28.5% reported using any contraception at last intercourse and 22.6% reported using a condom at last intercourse. Condom use among sexually active adolescents was lowest among 12th graders (13.5%, p < 0.001) and girls (16.8%, p = 0.004). CONCLUSIONS: Our findings suggest that young, unmarried, never pregnant women face an unmet need for family planning. Additionally, women with lower access to and use of healthcare services have lower use of family planning.

Epitopes recognition of SARS-CoV-2 nucleocapsid RNA binding domain by human monoclonal antibodies.

Coronavirus nucleocapsid protein (NP) of SARS-CoV-2 plays a central role in many functions important for virus proliferation including packaging and protecting genomic RNA. The protein shares sequence, structure, and architecture with nucleocapsid proteins from betacoronaviruses. The N-terminal domain (NPRBD) binds RNA and the C-terminal domain is responsible for dimerization. After infection, NP is highly expressed and triggers robust host immune response. The anti-NP antibodies are not protective and not neutralizing but can effectively detect viral proliferation soon after infection. Two structures of SARS-CoV-2 NPRBD were determined providing a continuous model from residue 48 to 173, including RNA binding region and key epitopes. Five structures of NPRBD complexes with human mAbs were isolated using an antigen-bait sorting. Complexes revealed a distinct complement-determining regions and unique sets of epitope recognition. This may assist in the early detection of pathogens and designing peptide-based vaccines. Mutations that significantly increase viral load were mapped on developed, full length NP model, likely impacting interactions with host proteins and viral RNA.

Postabortion care service availability, readiness, and access in Burkina Faso: results from linked female-facility cross-sectional data.

BACKGROUND: Little is known about postabortion care (PAC) services in Burkina Faso, despite PAC's importance as an essential and life-saving component of emergency obstetric care. This study aims to evaluate PAC service availability, readiness, and accessibility in Burkina Faso. METHODS: Data for this study come from the Performance Monitoring for Action (PMA) Burkina Faso project and the Harmonized Health Facility Assessment (HHFA) conducted by the Institut de Recherche en Sciences de la Santé and the Ministry of Health. PMA data from a representative sample of women aged 15-49 (n = 6,385) were linked via GPS coordinates to HHFA facility data (n = 2,757), which included all public and private health facilities in Burkina Faso. We assessed readiness to provide basic and comprehensive PAC using the signal functions framework. We then calculated distance to facilities and examined percent within 5 kms of a facility with any PAC, basic PAC, and comprehensive PAC overall and by women's background characteristics. RESULTS: PAC services were available in 46.4% of health facilities nationwide; only 38.3% and 35.0% of eligible facilities had all basic and comprehensive PAC signal functions, respectively. Removal of retained products of conception was the most common missing signal function for both basic and comprehensive PAC, followed by provision of any contraception (basic) or any LARC (comprehensive). Nearly 85% of women lived within 5 km of a facility providing any PAC services, while 50.5% and 17.4% lived within 5 km of a facility providing all basic PAC and all comprehensive PAC signal functions, respectively. Women with more education, greater wealth, and those living in urban areas had greater odds of living within 5 km of a facility with offering PAC, basic PAC, or comprehensive PAC. CONCLUSIONS: Results indicate a need for increased PAC availability and readiness, prioritizing basic PAC services at the primary level-the main source of care for many women-which would reduce structural disparities in access. The current deficiencies in PAC signal a need for broader strengthening of the primary healthcare services in Burkina Faso to reduce the burden of unsafe abortion-related morbidity and mortality while improving maternal health outcomes more broadly.

An Updated Equitable Model of Readiness for Transition to Adult Care: Content Validation in Young People With Sickle Cell Disease.

Importance: Despite elevated health risks during young adulthood, many adolescents and young adults with serious health care needs face barriers during the transfer to an adult specialty practitioner, and health disparities may occur during the transition. Objective: To validate the content of an updated Social-Ecological Model of Adolescent and Young Adult Readiness for Transition to Promote Health Equity (SMART-E) in a group of adolescents and young adults with sickle cell disease (SCD) and their supports. Design, Setting, and Participants: Health equity framework components were reviewed. Systems of power (eg, institutional and practitioner bias) and environments or networks (eg, peer or school support) were added as SMART-E preexisting factors, and health literacy was included within readiness factors. Adolescents and young adults aged 16 to 29 years with SCD, caregivers, and practitioners participated in this convergent, mixed-methods study within Children's Hospital of Philadelphia between January and August 2022. Main Outcomes and Measures: Content validity was assessed through nominations of top 3 most important transition barriers prior to interviews and focus groups, ratings on importance of SMART-E factors (0-4 scale; ratings >2 support validity) after interviews and focus groups, nominations of 3 most important factors for transition and for health equity, and qualitative content analysis of interview transcripts. Results: The study enrolled 10 pediatric adolescents and young adults (mean [SD] age, 18.6 [2.9] years; 4 female and 6 male), 10 transferred adolescents and young adults (mean [SD] age, 22.9 [2.1] years; 8 female and 2 male), 9 caregivers (mean [SD] age, 49.8 [8.7] years; 5 female and 4 male), and 9 practitioners (mean [SD] age, 45.6 [10.5] years; 8 female and 1 male). Quantitative ratings supported the content validity of SMART-E and met established criteria for validity. Systems of power was the most endorsed transition barrier (14 of 38 participants) reported prior to interviews and focus groups. After the interview, participants endorsed all SMART-E factors as important for transition, with new factors systems of power and environments and networks rated at a mean (SD) 2.8 (1.23) and 3.1 (0.90), respectively, on a 0 to 4 scale of importance. The most important factors for transition and equity varied by participant group, with all factors being endorsed, supporting the comprehensiveness of SMART-E. Qualitative data corroborated quantitative findings, further supporting validity, and minor modifications were made to definitions. Conclusions and Relevance: SMART-E obtained initial content validation with inclusion of health equity factors for adolescents and young adults with SCD, caregivers, and practitioners. The model should be evaluated in other populations of adolescents and young adults with chronic disease.

Homodimeric Granzyme A Opsonizes Mycobacterium tuberculosis and Inhibits Its Intracellular Growth in Human Monocytes via Toll-Like Receptor 4 and CD14.

Mycobacterium tuberculosis (Mtb)-specific γ9δ2 T cells secrete granzyme A (GzmA) protective against intracellular Mtb growth. However, GzmA-enzymatic activity is unnecessary for pathogen inhibition, and the mechanisms of GzmA-mediated protection remain unknown. We show that GzmA homodimerization is essential for opsonization of mycobacteria, altered uptake into human monocytes, and subsequent pathogen clearance within the phagolysosome. Although monomeric and homodimeric GzmA bind mycobacteria, only homodimers also bind cluster of differentiation 14 (CD14) and Toll-like receptor 4 (TLR4). Without access to surface-expressed CD14 and TLR4, GzmA fails to inhibit intracellular Mtb. Upregulation of Rab11FIP1 was associated with inhibitory activity. Furthermore, GzmA colocalized with and was regulated by protein disulfide isomerase AI (PDIA1), which cleaves GzmA homodimers into monomers and prevents Mtb inhibitory activity. These studies identify a previously unrecognized role for homodimeric GzmA structure in opsonization, phagocytosis, and elimination of Mtb in human monocytes, and they highlight PDIA1 as a potential host-directed therapy for prevention and treatment of tuberculosis, a major human disease.

Oxidative DNA damage on the VEGF G-quadruplex forming promoter is repaired via long-patch BER.

In response to oxidative damage, base excision repair (BER) enzymes perturb the structural equilibrium of the VEGF promoter between B-form and G4 DNA conformations, resulting in epigenetic-like modifications of gene expression. However, the mechanistic details remain enigmatic, including the activity and coordination of BER enzymes on the damaged G4 promoter. To address this, we investigated the ability of each BER factor to conduct its repair activity on VEGF promoter G4 DNA substrates by employing pre-steady-state kinetics assays and in vitro coupled BER assays. OGG1 was able to initiate BER on double-stranded VEGF promoter G4 DNA substrates. Moreover, pre-steady-state kinetics revealed that compared to B-form DNA, APE1 repair activity on the G4 was decreased ~two-fold and is the result of slower product release as opposed to inefficient strand cleavage. Interestingly, Pol ß performs multiple insertions on G4 substrates via strand displacement DNA synthesis in contrast to a single insertion on B-form DNA. The multiple insertions inhibit ligation of the Pol ß products, and hence BER is not completed on the VEGF G4 promoter substrates through canonical short-patch BER. Instead, repair requires the long-patch BER flap-endonuclease activity of FEN1 in response to the multiple insertions by Pol ß prior to ligation. Because the BER proteins and their repair activities are a key part of the VEGF transcriptional enhancement in response to oxidative DNA damage of the G4 VEGF promoter, the new insights reported here on BER activity in the context of this promoter are relevant toward understanding the mechanism of transcriptional regulation.

Sex-based outcomes in surgical repair of acute type A aortic dissection: A meta-analysis and meta-regression.

OBJECTIVE: Epidemiologic variation with respect to sex has been established in aortic dissection. However, current literature on sex-based outcomes in patients with aortic dissection is conflicting. In this study we aimed to compare perioperative outcomes according to sex in patients treated surgically for acute type A aortic dissection. METHODS: PubMed/MEDLINE, Embase, and Web of Science were searched for studies that reported sex-based differences in postoperative outcomes among patients with acute type A aortic dissection. The primary outcome was in-hospital/30-day mortality, and secondary outcomes included postoperative stroke, renal failure requiring dialysis, and reoperation for bleeding. Data were aggregated using the random effects model as pooled risk ratio (RR). Meta-regression was applied to identify sources of heterogeneity between studies. RESULTS: Nine of 1022 studies were included for final analysis comprising 3338 female and 5979 male participants. Compared with male sex, female sex was associated with similar in-hospital/30-day mortality (RR, 1.04; 95% CI, 0.85-1.28; P = .67), postoperative stroke risk (RR, 1.07; 95% CI, 0.91-1.25; P = .43), and postoperative risk of acute renal failure requiring dialysis (RR, 0.84; 95% CI, 0.59-1.19; P = .32). A decreased risk of reoperation for bleeding (RR, 0.84; 95% CI, 0.75-0.94; P < .01) was observed in female participants. Meta-regression analysis indicated that differences in preoperative shock were a source of heterogeneity in the sex difference in in-hospital/30-day mortality across studies. CONCLUSIONS: Among patients treated surgically for acute type A aortic dissection, female sex was not associated with increased risk of short-term mortality nor with major postoperative complications. Male sex was associated with a greater risk of postoperative bleeding.

Antigen-specific memory NK cell responses against HIV and influenza use the NKG2/HLA-E axis.

Multiple studies have broadened the roles of natural killer (NK) cells functioning as purely innate lymphocytes by demonstrating that they are capable of putative antigen-specific immunological memory against multiple infectious agents including HIV-1 and influenza. However, the mechanisms underlying antigen specificity remain unknown. Here, we demonstrate that antigen-specific human NK cell memory develops upon exposure to both HIV and influenza, unified by a conserved and epitope-specific targetable mechanism largely dependent on the activating CD94/NKG2C receptor and its ligand HLA-E. We validated the permanent acquisition of antigen specificity by individual memory NK cells by single-cell cloning. We identified elevated expression of KLRG1, α4ß7, and NKG2C as biomarkers of antigen-specific NK cell memory through complex immunophenotyping. Last, we uncovered individual HLA-E-restricted peptides that may constitute the dominant NK cell response in HIV-1- and influenza-infected persons in vivo. Our findings clarify the mechanisms contributing to antigen-specific memory NK cell responses and suggest that they could be potentially targeted therapeutically for vaccines or other therapeutic interventions.

Safety Aspects and Rational Use of Single Intramuscular Dose Ceftriaxone: Clinical Insights on the Management of Uncomplicated Gonococcal Infections.

Gonorrhea, a sexually transmitted infection caused by Neisseria gonorrhoeae, is a grave public health concern. Gonorrhea is the second most reported sexually transmitted infection worldwide. The treatment of uncomplicated gonococcal infections has evolved dramatically in response to the emergence of antimicrobial resistance. Multiple resistance mechanisms (for example, beta-lactamase production, antimicrobial efflux, and target site modification) exist, some of which may cause multidrug-resistance. Ceftriaxone was first recommended as an option for uncomplicated gonococcal infections in 1985, and it is now a mainstay of therapy in all clinical practice guidelines. Ceftriaxone has consistently shown high microbiologic cure rates in clinical trials, and it has demonstrated an excellent safety profile. Although its use may be limited in patients with hypersensitivity to penicillins, the risk of using ceftriaxone in such patients is overestimated. The emergence of reduced ceftriaxone susceptibility in N. gonorrhoeae, coupled with a lack of diverse treatment alternatives and the limited pipeline of new antimicrobials, is a significant threat to the treatment of gonorrhea.

Energetics of high temperature degradation of fentanyl into primary and secondary products.

Fentanyl is a synthetic opioid used for managing chronic pain. Due to its higher potency (50-100×) than morphine, fentanyl is also an abused drug. A sensor that could detect illicit fentanyl by identifying its thermally degraded fragments would be helpful to law enforcement. While experimental studies have probed the thermal degradation of fentanyl, little theoretical work has been done to understand the mechanism. Here, we studied the thermal degradation pathways of fentanyl using extensive ab initio molecular dynamics simulations combined with enhanced sampling via multiple-walker metadynamics. We calculated the free energy profile for each bond suggested earlier as a potential degradation point to map the thermodynamic driving forces. We also estimated the forward attempt rate of each bond degradation reaction to gain information about degradation kinetics.

Temperature-Dependent Selection of Reaction Pathways, Reactive Species, and Products during Postsynthetic Selenization of Copper Sulfide Nanoparticles.

Rational design of elaborate, multicomponent nanomaterials is important for the development of many technologies such as optoelectronic devices, photocatalysts, and ion batteries. Combination of metal chalcogenides with different anions, such as in CdS/CdSe structures, is particularly effective for creating heterojunctions with valence band offsets. Seeded growth, often coupled with cation exchange, is commonly used to create various core/shell, dot-in-rod, or multipod geometries. To augment this library of multichalcogenide structures with new geometries, we have developed a method for postsynthetic transformation of copper sulfide nanorods into several different classes of nanoheterostructures containing both copper sulfide and copper selenide. Two distinct temperature-dependent pathways allow us to select from several outcomes-rectangular, faceted Cu2-xS/Cu2-xSe core/shell structures, nanorhombuses with a Cu2-xS core, and triangular deposits of Cu2-xSe or Cu2-x(S,Se) solid solutions. These different outcomes arise due to the evolution of the molecular components in solution. At lower temperatures, slow Cu2-xS dissolution leads to concerted morphology change and Cu2-xSe deposition, while Se-anion exchange dominates at higher temperatures. We present detailed characterization of these Cu2-xS-Cu2-xSe nanoheterostructures by transmission electron microscopy (TEM), powder X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning TEM-energy-dispersive spectroscopy. Furthermore, we correlate the selenium species present in solution with the roles they play in the temperature dependence of nanoheterostructure formation by comparing the outcomes of the established reaction conditions to use of didecyl diselenide as a transformation precursor.

Color as an Interspecific Badge of Status: A Comparative Test.

AbstractAnimals as diverse as cephalopods, insects, fish, and mammals signal social dominance to conspecifics to avoid costly fights. Even though between-species fights may be equally costly, the extent to which dominance signals are used between species is unknown. Here, we test the hypothesis that differences in color are associated with dominance between closely related species that aggressively interact over resources, examining between-species variation in colors that are used in within-species badges of status (black, white, and carotenoid coloration) in a comparative analysis of diverse species of birds. We found that dominant species have more black, on average, than subordinate species, particularly in regions important for aggressive signaling (face, throat, and bill). Furthermore, dominant species were more likely to have more black in comparisons in which the dominant species was similar in size or smaller than the subordinate, suggesting that black may be a more important signal when other signals of dominance (size) are missing. Carotenoid colors (i.e., red, pink, orange, and yellow) were not generally associated with dominance but may signal dominance in some taxonomic groups. White may have opposing functions: white was associated with dominance in species in which black was also associated with dominance but was associated with subordinance in species in which carotenoid-based dominance signals may be used. Overall, these results provide new evidence that colors may function broadly as signals of dominance among competing species. Such signals could help to mediate aggressive interactions among species, thereby reducing some costs of co-occurrence and facilitating coexistence in nature.

Thermally Induced Domain Migration and Interfacial Restructuring in Cation Exchanged ZnS-Cu1.8S Heterostructured Nanorods.

Partial cation exchange reactions can be used to rationally design and synthesize heterostructured nanoparticles that are useful targets for applications in photocatalysis, nanophotonics, thermoelectrics, and medicine. Such reactions introduce intraparticle frameworks that define the spatial arrangements of different materials within a heterostructured nanoparticle, as well as the orientations and locations of their interfaces. Here, we show that upon heating to temperatures relevant to their synthesis and applications, the ZnS regions and Cu1.8S/ZnS interfaces of heterostructured ZnS-Cu1.8S nanorods migrate and restructure. We first use partial cation exchange reactions to synthesize a library of seven distinct samples containing various patches, bands, and tips of ZnS embedded within Cu1.8S nanorods. Upon annealing in solution or in air, ex situ TEM analysis shows evidence that the ZnS domains migrate in different ways, depending upon their sizes and locations. Using differential scanning calorimetry, we correlate the threshold temperature for ZnS migration to the superionic transition temperature of Cu1.8S, which facilitates rapid diffusion throughout the nanorods. We then use in situ thermal TEM to study the evolution of individual ZnS-Cu1.8S nanorods upon heating. We find that ZnS domain migration occurs through a ripening process that minimizes small patches with higher-energy interfaces in favor of larger bands and tips having lower-energy interfaces, as well as through restructuring of higher-energy Cu1.8S/ZnS interfaces. Notably, Cu1.8S nanorods containing multiple patches of ZnS thermally transform into ZnS-Cu1.8S heterostructured nanorods having ZnS tips and/or central bands, which provides mechanistic insights into how these commonly observed products form during synthesis.