Illegal synthetic dyes in spices: a Singapore case study.

Some synthetic dyes are fraudulently added into spices to appeal visually to consumers. Food regulations in several countries, including the United States, Australia, Japan and the European Union, strictly prohibit the use of unauthorised synthetic dyes in food. Nevertheless, illegal practices persist, where spices contaminated with potentially carcinogenic dyes have been documented, posing potential health risks to consumers. In the present study, 14 synthetic dyes were investigated through liquid chromatography/tandem mass spectrometry in 252 commercially available spices in the Singapore market. In 18 out of these (7.1%) at least 1 illegal dye was detected at concentrations ranging from 0.010 to 114 mg/kg. Besides potential health risks, presence of these adulterants also reflects the economic motivations behind their fraudulent use. Findings in the present study further emphasise the need for increased public awareness, stricter enforcement, and continuous monitoring of illegal synthetic dyes in spices to ensure Singapore's food safety.

Use of a Sheath and Stylet for a Difficult Dorsal Root Ganglion Stimulation Lead Extraction: A Case Report.

Dorsal root ganglion stimulation (DRG-S) is a relatively new neuromodulation technique that has shown promising results in the treatment of chronic pain conditions. We present a case of a difficult lead extraction during the explantation of a DRG-S device. The lead was unable to be removed despite multiple attempts until a sheath and stylet were used to facilitate extraction. As DRG-S utilization becomes more widespread, DRG-S device explantation will inevitably become more common. The technique described in this report may be beneficial in certain cases of difficult DRG-S lead extraction.

Platform development for high-throughput optimization of perfusion processes-Part II: Variation of perfusion rate strategies in microwell plates.

The biopharmaceutical industry is replacing fed-batch with perfusion processes to take advantage of reduced capital and operational costs due to the operation at high cell densities (HCD) and improved productivities. HCDs are achieved by cell retention and continuous medium exchange, which is often based on the cell-specific perfusion rate (CSPR). To obtain a cost-productive process the perfusion rate must be determined for each process individually. However, determining optimal operating conditions remain labor-intensive and time-consuming experiments, as investigations are performed in lab-scale perfusion bioreactors. Small-scale models such as microwell plates (MWPs) provide an option for screening multiple perfusion rates in parallel in a semi-perfusion mimic. This study investigated two perfusion rate strategies applied to the MWP platform operated in semi-perfusion. The CSPR-based perfusion rate strategy aimed to maintain multiple CSPR values throughout the cultivation and was compared to a cultivation with a perfusion rate of 1 RV d-1 . The cellular performance was investigated with the dual aim (i) to achieve HCD, when inoculating at conventional and HCDs, and (ii) to maintain HCDs, when applying an additional manual cell bleed. With both perfusion rate strategies viable cell concentrations up to 50 × 106 cells mL-1 were achieved and comparable results for key metabolites and antibody product titers were obtained. Furthermore, the combined application of cell bleed and CSPR-based medium exchange was successfully shown with similar results for growth, metabolites, and productivities, respectively, while reducing the medium consumption by up to 50% for HCD cultivations.

A Synthetic Strategy toward S-, N-, and O-Heterocyclooctynes Facilitates Bioconjugation Using Multifunctional Handles.

Over the past two decades, the introduction of bioorthogonal reactions has transformed the ways in which chemoselective labeling, isolation, imaging, and drug delivery are carried out in a complex biological milieu. A key feature of a good bioorthogonal probe is the ease with which it can be attached to a target compound through bioconjugation. This paper describes the expansion of the utility of a class of unique S-, N-, and O-containing heterocyclooctynes (SNO-OCTs), which show chemoselective reactivity with type I and type II dipoles and divergent reactivities in response to electronic tuning of the alkyne. Currently, bioconjugation of SNO-OCTs to a desired target is achieved through an inconvenient aryl or amide linker at the sulfamate nitrogen. Herein, a new synthetic approach toward general SNO-OCT scaffolds is demonstrated that enables the installation of functional handles at both propargylic carbons of the heterocycloalkyne. This capability increases the utility of SNO-OCTs as labeling reagents through the design of bifunctional bioorthogonal probes with expanded capabilities. NMR kinetics also revealed up to sixfold improvement in cycloaddition rates of new analogues compared to first-generation SNO-OCTs.

Effect of inner diameter, filter length, and pore size on hollow fiber filter fouling during perfusion cell culture.

As the need for higher volumetric productivity in biomanufacturing grows, biopharmaceutical companies are increasingly investing in a perfusion cell culture process, most commonly one that uses a hollow fiber filter as the cell retention device. A current challenge with using hollow fiber filters is fouling of the membrane, which reduces product sieving and can increase transmembrane pressure (TMP) past process limitations. In this work, the impact of hollow fiber filter geometries on product sieving and hydraulic membrane resistance profiles is evaluated in a tangential flow filtration (TFF) perfusion system. The hollow fibers tested had lengths ranging from 19.8 to 41.5 cm, inner diameters (IDs) ranging from 1.0 to 2.6 mm, and pore sizes of 0.2 or 0.65 µm. The results showed that the shortest hollow fibers experienced higher product sieving while larger IDs contributed to both higher product sieving and lower hydraulic membrane resistances, illustrating the impact of filter geometry on process performance. The results also showed 0.2 µm pore size filters maintain higher product sieving, but also higher membrane resistances compared to 0.65 µm pore size filters. This study highlights the need for optimized hollow fiber filter geometries to maximize use of the membrane area, which in turn can reduce production costs and increase scalability of the perfusion process.

Platform development for high-throughput optimization of perfusion processes: Part I: Implementation of cell bleeds in microwell plates.

The promise of continuous processing to increase yields and improve product quality of biopharmaceuticals while decreasing the manufacturing footprint is transformative. Developing and optimizing perfusion operations requires screening various parameters, which is expensive and time-consuming when using benchtop bioreactors. Scale-down models (SDMs) are the most feasible option for high-throughput data generation and condition screening. However, new SDMs mimicking perfusion are required, enabling experiments to be run in parallel. In this study, a method using microwell plates (MWP) operating in semi-perfusion mode with an implemented cell bleed step is presented. A CHO cell line was cultivated in a 24-well MWP (Vw = 1.2 mL) and grown at four high cell density (HCD) setpoints. Quasi steady-state condition was obtained by manually performing cell bleeds followed by a total medium exchange after centrifugation. Further, two HCD setpoints were scaled up (VW = 30 mL), comparing a squared six-well deepwell plate (DWP) to shake flasks (SF). This evaluation showed comparable results between systems (DWP vs. SF) and scales (MWP vs. DWP + SF). The results show that the well-plate-based methods are suitable to perform HCD and quasi steady-state cultivations providing a robust solution to industrially relevant challenges such as cell clone and media selection.

Determination of ethoxyquin by ultra-high performance liquid chromatography with tandem mass spectrometry and a Singapore survey of ethoxyquin residues in eggs, egg products and poultry.

In this study, an advanced ultra-high performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method was developed for quantifying ethoxyquin (EQ). The approach employed a distinctive antioxidant added extraction step designed to prevent ethoxyquin decomposition and maintain analytical precision. This method effectively determines residue levels of EQ in eggs, processed egg products, poultry muscle, salmon, and liquid milk. The method was shown to have a limit of quantitation (LOQ) for eggs, milk, salmon, and chicken muscle of 1.5 µg/kg, 1.9 µg/kg, 2.1 µg/kg, and 1.2 µg/kg, respectively. The recoveries of EQ ranged from 79.2% to 107.6%, with a relative standard deviation (RSD) below 8.4%. A surveillance study for the presence of EQ in different types of eggs and poultry muscle available in Singapore was conducted and a total of 140 samples were tested. EQ residues in all samples were found to be below the U.S. Food and Drug Administration (FDA) MRLs of 500 µg/kg. Some samples of salted and preserved eggs from China were detected with higher concentration of EQ.

Airway 'Resistotypes' and Clinical Outcomes in Bronchiectasis.

INTRODUCTION: Application of whole-genome shotgun metagenomics to the airway microbiome in bronchiectasis highlights a diverse pool of antimicrobial resistance genes: the 'resistome', the clinical significance of which remains unclear. METHODS: Individuals with bronchiectasis were prospectively recruited into cross-sectional and longitudinal cohorts (n=280) including the international multicentre cross-sectional Cohort of Asian and Matched European Bronchiectasis 2 study (CAMEB 2; n=251) and two independent cohorts, one describing patients experiencing acute exacerbation and a further cohort of patients undergoing P. aeruginosa eradication treatment. Sputum was subjected to metagenomic sequencing and the bronchiectasis resistome evaluated in association with clinical outcomes and underlying host microbiomes. RESULTS: The bronchiectasis resistome features a unique resistance gene profile and elevated counts of aminoglycoside, bicyclomycin, phenicol, triclosan and multi-drug resistance genes. Longitudinally, it exhibits within-patient stability over time and during exacerbations despite between-patient heterogeneity. Proportional differences in baseline resistome profiles including increased macrolide and multi-drug resistance genes associate with shorter intervals to next exacerbation, while distinct resistome archetypes associate with frequent exacerbations, poorer lung function, geographic origin, and the host microbiome. Unsupervised analysis of resistome profiles identified two clinically relevant 'resistotypes' RT1 and RT2, the latter characterized by poor clinical outcomes, increased multi-drug resistance and P. aeruginosa. Successful targeted eradication in P. aeruginosa-colonized individuals mediated reversion from RT2 to RT1, a more clinically favourable resistome profile demonstrating reduced resistance gene diversity. CONCLUSION: The bronchiectasis resistome associates with clinical outcomes, geographic origin, and the underlying host microbiome. Bronchiectasis 'resistotypes' link to clinical disease and are modifiable through targeted antimicrobial therapy. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Multivitamin/Multimineral Supplementation Prevents or Reverses Decline in Vitamin Biomarkers and Cellular Energy Metabolism in Healthy Older Men: A Randomized, Double-Blind, Placebo-Controlled Study.

Despite the reported prevalence of micronutrient deficiencies in older adults, it is not yet established whether multivitamin/multimineral (MV/MM) supplements improve blood micronutrient status in individuals over the age of 65. Therefore, a cohort of 35 healthy men (>67 years) was recruited for an MV/MM supplementation trial. The primary endpoint was, as an indicator of micronutrient status, changes in blood micronutrient biomarkers from baseline to at least six months of supplementation with MV/MM or placebo. The secondary endpoint was basal O2 consumption in monocytes as an indicator of cellular metabolism. MV/MM supplementation improved blood concentrations of pyridoxal phosphate, calcifediol, α-tocopherol, and ß-carotene concentrations throughout the cohort. By contrast, those in the placebo group generally showed declines in blood vitamin concentrations and an increased prevalence of suboptimal vitamin status during the study period. On the other hand, MV/MM supplementation did not significantly affect blood mineral concentrations, i.e., calcium, copper, iron, magnesium, and zinc. Interestingly, MV/MM supplementation prevented the decline in monocyte O2 consumption rate. Overall, MV/MM use improves or prevents declines in vitamin, but not mineral, status and limits declines in cellular O2 consumption, which may have important implications for metabolism and immune health in healthy older men.

Mutations identified in engineered Escherichia coli with a reduced genome.

Characterizing genes that regulate cell growth and survival in model organisms is important for understanding higher organisms. Construction of strains harboring large deletions in the genome can provide insights into the genetic basis of cell growth compared with only studying wild-type strains. We have constructed a series of genome-reduced strains with deletions spanning approximately 38.9% of the E. coli chromosome. Strains were constructed by combining large deletions in chromosomal regions encoding nonessential gene groups. We also isolated strains Δ33b and Δ37c, whose growth was partially restored by adaptive laboratory evolution (ALE). Genome sequencing of nine strains, including those selected following ALE, identified the presence of several Single Nucleotide Variants (SNVs), insertions, deletions, and inversions. In addition to multiple SNVs, two insertions were identified in ALE strain Δ33b. The first was an insertion at the promoter region of pntA, which increased cognate gene expression. The second was an insertion sequence (IS) present in sibE, encoding the antitoxin in a toxin-antitoxin system, which decreased expression of sibE. 5 strains of Δ37c independently isolated following ALE harboring multiple SNVs and genetic rearrangements. Interestingly, a SNV was identified in the promoter region of hcaT in all five strains, which increased hcaT expression and, we predict, rescued the attenuated Δ37b growth. Experiments using defined deletion mutants suggested that hcaT encodes a 3-phenylpropionate transporter protein and is involved in survival during stationary phase under oxidative stress. This study is the first to document accumulation of mutations during construction of genome-reduced strains. Furthermore, isolation and analysis of strains derived from ALE in which the growth defect mediated by large chromosomal deletions was rescued identified novel genes involved in cell survival.

VSIG4 interaction with heparan sulfates inhibits VSIG4-complement binding.

V-set and immunoglobulin domain-containing 4 (VSIG4) is a complement receptor of the immunoglobulin superfamily that is specifically expressed on tissue resident macrophages, and its many reported functions and binding partners suggest a complex role in immune function. VSIG4 is reported to have a role in immune surveillance as well as in modulating diverse disease phenotypes such as infections, autoimmune conditions, and cancer. However, the mechanism(s) governing VSIG4's complex, context-dependent role in immune regulation remains elusive. Here, we identify cell surface and soluble glycosaminoglycans, specifically heparan sulfates, as novel binding partners of VSIG4. We demonstrate that genetic deletion of heparan sulfate synthesis enzymes or cleavage of cell-surface heparan sulfates reduced VSIG4 binding to the cell surface. Furthermore, binding studies demonstrate that VSIG4 interacts directly with heparan sulfates, with a preference for highly sulfated moieties and longer glycosaminoglycan chains. To assess the impact on VSIG4 biology, we show that heparan sulfates compete with known VSIG4 binding partners C3b and iC3b. Furthermore, mutagenesis studies indicate that this competition occurs through overlapping binding epitopes for heparan sulfates and complement on VSIG4. Together these data suggest a novel role for heparan sulfates in VSIG4-dependent immune modulation.

High-Throughput Photo- and Electrochemical sp2-sp3 Cross-Electrophile Coupling to Access Novel Tedizolid Analogs.

The development of practical synthetic protocols integrating novel technologies may enable rapid and broad exploration of chemical space in medicinal chemistry campaigns. Cross-electrophile coupling (XEC) allows the diversification of an aromatic core with alkyl halides to increase the sp3 character. Herein, we apply two alternative approaches via either photo- or electro-catalyzed XEC and showcase their complementarity to access novel tedizolid analogs. The parallel photochemical and electrochemical reactors with high light intensity and constant voltage respectively were chosen to yield good conversions, which allowed access to a wide range of derivatives in a much shorter time frame.

Validation of user-friendly models predicting extracapsular extension in prostate cancer patients.

Objective: There are many models to predict extracapsular extension (ECE) in patients with prostate cancer. We aimed to externally validate several models in a Japanese cohort. Methods: We included patients treated with robotic-assisted radical prostatectomy for prostate cancer. The risk of ECE was calculated for each patient in several models (prostate side-specific and non-side-specific). Model performance was assessed by calculating the receiver operating curve and the area under the curve (AUC), calibration plots, and decision curve analyses. Results: We identified ECE in 117 (32.9%) of the 356 prostate lobes included. Patients with ECE had a statistically significant higher prostate-specific antigen level, percentage of positive digital rectal examination, percentage of hypoechoic nodes, percentage of magnetic resonance imaging nodes or ECE suggestion, percentage of biopsy positive cores, International Society of Urological Pathology grade group, and percentage of core involvement. Among the side-specific models, the Soeterik, Patel, Sayyid, Martini, and Steuber models presented AUC of 0.81, 0.78, 0.77, 0.75, and 0.73, respectively. Among the non-side-specific models, the memorial Sloan Kettering Cancer Center web calculator, the Roach formula, the Partin tables of 2016, 2013, and 2007 presented AUC of 0.74, 0.72, 0.64, 0.61, and 0.60, respectively. However, the 95% confidence interval for most of these models overlapped. The side-specific models presented adequate calibration. In the decision curve analyses, most models showed net benefit, but it overlapped among them. Conclusion: Models predicting ECE were externally validated in Japanese men. The side-specific models predicted better than the non-side-specific models. The Soeterik and Patel models were the most accurate performing models.

Correlation between extended pelvic lymph node dissection and urinary incontinence at early phase after robot-assisted radical prostatectomy.

OBJECTIVES: To investigate the impact of extended pelvic lymph node dissection (ePLND) on urinary incontinence (UI) at early post-surgery robot-assisted radical prostatectomy (RARP). METHODS: Patients who underwent RARP without cavernous nerve sparing were included between 2014 and 2019. Patient data were obtained prospectively. The associations between ePLND and postoperative urinary continence were defined as a maximum of one daily pad use. International prostate symptom score (IPSS) was examined. Expression of synaptophysin and tyrosine hydroxylase (TH) in perilymph node adipose tissue (PLA) was evaluated by immunohistochemistry. RESULTS: In total, 186 and 163 patients underwent RARP with and without ePLND. Urinary continence rate at 1 month postoperatively among patients with ePLND was lower than those without ePLND (24.1% vs. 35.1%, p < 0.05), however, not significantly different at 3, 6, and 12 months after RARP (57.4 vs. 62.6%, 73.1 vs. 74.2%, and 83.0 vs. 81.2%, respectively). Total and voiding plus postvoiding IPSS scores at 1 month were higher in patients with ePLND than in those without ePLND (14.5 ± 0.5 vs. 13.6 ± 0.6, 7.0 ± 0.3 vs. 6.2 ± 0.4, respectively, p < 0.05). In univariate and multivariate analyses, larger prostate volume and ePLND were factors associated with an increased UI rate. Among patients who underwent ePLND, synaptophysin and TH-positive nerve fibers were detected in PLA. CONCLUSIONS: Detection of synaptophysin and TH-immunopositive nerves suggested denervation of sympathetic and peripheral nerves caused by ePLND might be associated with a higher UI rate and poor urinary symptoms at an early stage after RARP.

Novel nomogram to predict biochemical recurrence-free survival after radical prostatectomy.

PURPOSE: Conditional survival represents the probability of subsequent survival given that patients have already survived a certain length of time. Several models predict biochemical recurrence (BCR) after radical prostatectomy. However, none of them include postoperative prostate-specific antigen (PSA). We aimed to analyze BCR-free survival evolution over time and develop a nomogram incorporating the postoperative PSA value to predict BCR-free survival. MATERIAL AND METHODS: We included patients treated with robot-assisted radical prostatectomy (RARP) for prostate cancer between 2009 and 2021 and calculated conditional survival. Cox proportional hazard regression analysis was used to assess the predictive variables of BCR. We developed a nomogram predicting BCR-free survival three and five years after RARP. We used c-index and decision curve analyses to compare the nomogram with the Cancer of the Prostate Risk Assessment post-Surgical (CAPRA-S) score. RESULTS: We included 718 patients. The overall 3- and 5-year BCR-free survival rates were 85.1% and 75.7%, respectively. The 5-year BCR-free survival rates increased to 78.9%, 82.9%, 85.2%, and 84.7% for patients surviving 1, 2, 3, and 4 years without BCR, respectively. We developed a nomogram including the pathological Gleason score and T stage, positive surgical margin, PSA ≥ 0.05 ng/mL at one year, and lymph node involvement to predict BCR at 3 and 5 years postoperatively. Our nomogram presented a higher c-index (0.89) than the CAPRA-S score (0.78; p = 0.001) and a positive net benefit at 3 and 5 years postoperatively in the decision curve analyses. CONCLUSION: The 5-year conditional BCR-free survival increased with survival without BCR. The developed nomogram significantly improved the accuracy in predicting BCR-free survival after RARP.

The establishment of COPD organoids to study host-pathogen interaction reveals enhanced viral fitness of SARS-CoV-2 in bronchi.

Chronic obstructive pulmonary disease (COPD) is characterised by airflow limitation and infective exacerbations, however, in-vitro model systems for the study of host-pathogen interaction at the individual level are lacking. Here, we describe the establishment of nasopharyngeal and bronchial organoids from healthy individuals and COPD that recapitulate disease at the individual level. In contrast to healthy organoids, goblet cell hyperplasia and reduced ciliary beat frequency were observed in COPD organoids, hallmark features of the disease. Single-cell transcriptomics uncovered evidence for altered cellular differentiation trajectories in COPD organoids. SARS-CoV-2 infection of COPD organoids revealed more productive replication in bronchi, the key site of infection in severe COVID-19. Viral and bacterial exposure of organoids induced greater pro-inflammatory responses in COPD organoids. In summary, we present an organoid model that recapitulates the in vivo physiological lung microenvironment at the individual level and is amenable to the study of host-pathogen interaction and emerging infectious disease.

CD22-targeted CD28 bispecific antibody enhances antitumor efficacy of odronextamab in refractory diffuse large B cell lymphoma models.

Although many patients with diffuse large B cell lymphoma (DLBCL) may achieve a complete response to frontline chemoimmunotherapy, patients with relapsed/refractory disease typically have poor outcomes. Odronextamab, a CD20xCD3 bispecific antibody that provides "signal 1" through the activation of the T cell receptor/CD3 complex, has exhibited early, promising activity for patients with highly refractory DLBCL in phase 1 trials. However, not all patients achieve complete responses, and many relapse, thus representing a high unmet medical need. Here, we investigated whether adding a costimulatory "signal 2" by engaging CD28 receptors on T cells could augment odronextamab activity. We demonstrate that REGN5837, a bispecific antibody that cross-links CD22-expressing tumor cells with CD28-expressing T cells, enhances odronextamab by potentiating T cell activation and cytolytic function. In preclinical DLBCL studies using human immune system-reconstituted animals, REGN5837 promotes the antitumor activity of odronextamab and induces intratumoral expansion of reprogrammable T cells while skewing away from a dysfunctional state. Although REGN5837 monotherapy shows limited activity and no toxicity in primate studies, it augments T cell activation when dosed in combination with odronextamab. In addition, analysis of non-Hodgkin lymphoma clinical samples reveals an increase in CD28+CD8+ T cells after odronextamab treatment, demonstrating the presence of a population that could potentially be targeted by REGN5837. Collectively, our data demonstrate that REGN5837 can markedly enhance the antitumor activity of odronextamab in preclinical NHL models, and the combination of these two bispecific antibodies may provide a chemotherapy-free approach for the treatment of DLBCL.

Psoas Muscle Volume Is a Predictive Marker of Fatigue and Anorexia in Prostate Cancer Patients Treated with Enzalutamide.

Introduction: Enzalutamide is approved for the treatment of patients with metastatic castration-resistant prostate cancer. Adverse effects (e.g., fatigue and anorexia) are often observed and cause difficulty with continuous therapy; however, no clinical data describing which patients are more likely to suffer adverse effects were observed. Therefore, this study hypothesized that body composition, comprising body fat distribution and psoas muscle volume, may affect the occurrence of subjective symptoms (e.g., fatigue and anorexia) in prostate cancer patients treated with enzalutamide. Methods: Adverse effects, especially fatigue, anorexia, insomnia, and pain, were retrospectively evaluated by CTCAE v4.0 criteria. Sixty-seven prostate cancer patients treated with enzalutamide were enrolled, and body fat, visceral fat percentage, and psoas muscle ratio (psoas muscle, in cubic centimeter/height, in meters) were calculated using computed tomography images evaluated before enzalutamide, with SYNAPSE VINCENT software. Univariate analysis was performed to identify the factors associated with adverse effects. Results: Univariate analysis showed that high psoas muscle ratio was significantly associated with fatigue (grade ≥ 2; odds ratio, 3.875; 95% confidence interval, 1.016-17.134; P = 0.047), but inversely related to anorexia (grade ≥ 2; odds ratio, 0.093; 95% confidence interval, 0.011-0.784; P = 0.029). Conclusions: Psoas muscle ratio is a predictive marker of fatigue and anorexia in patients treated with enzalutamide.

Synthesis of (+)-ribostamycin by catalytic, enantioselective hydroamination of benzene.

Aminoglycosides (AGs) represent a large group of pseudoglycoside natural products, in which several different sugar moieties are harnessed to an aminocyclitol core. AGs constitute a major class of antibiotics that target the prokaryotic ribosome of many problematic pathogens. Hundreds of AGs have been isolated to date, with 1,3-diaminocyclohexanetriol, known as 2-deoxystreptamine (2-DOS), being the most abundant aglycon core. However, owning to their diverse and complex architecture, all AG-based drugs are either natural substances or analogues prepared by late-stage modifications. Synthetic approaches to AGs are rare and lengthy; most studies involve semi-synthetic reunion of modified fragments. Here we report a bottom-up chemical synthesis of the 2-DOS-based AG antibiotic ribostamycin, which proceeds in ten linear operations from benzene. A key enabling transformation involves a Cu-catalyzed, enantioselective, dearomative hydroamination, which set the stage for the rapid and selective introduction of the remaining 2-DOS heteroatom functionality. This work demonstrates how the combination of a tailored, dearomative logic and strategic use of subsequent olefin functionalizations can provide practical and concise access to the AG class of compounds.

Investigation of independent reinforcement learning algorithms in multi-agent environments.

Independent reinforcement learning algorithms have no theoretical guarantees for finding the best policy in multi-agent settings. However, in practice, prior works have reported good performance with independent algorithms in some domains and bad performance in others. Moreover, a comprehensive study of the strengths and weaknesses of independent algorithms is lacking in the literature. In this paper, we carry out an empirical comparison of the performance of independent algorithms on seven PettingZoo environments that span the three main categories of multi-agent environments, i.e., cooperative, competitive, and mixed. For the cooperative setting, we show that independent algorithms can perform on par with multi-agent algorithms in fully-observable environments, while adding recurrence improves the learning of independent algorithms in partially-observable environments. In the competitive setting, independent algorithms can perform on par or better than multi-agent algorithms, even in more challenging environments. We also show that agents trained via independent algorithms learn to perform well individually, but fail to learn to cooperate with allies and compete with enemies in mixed environments.