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Herein we describe a method for combining supramolecular catalysis with imininum-based organocatalysis in the Diels-Alder cycloaddition reaction. Both supramolecular host and L-proline are required for the reaction to occur, implying that encapsulation of the substrates and co-catalyst are necessary for the reaction to occur. We explore the substrate scope for a variety of

Peptide-Centric Chimeric Antigen Receptors (PC-CARs), which recognize oncoprotein epitopes displayed by human leukocyte antigens (HLAs) on the cell surface, offer a promising strategy for targeted cancer therapy1. We have previously developed a PC-CAR targeting a neuroblastoma- associated PHOX2B peptide, leading to robust tumor cell lysis restricted by two common HLA allotypes2. Here, we determine the 2.1 Å structure of the PC-CAR:PHOX2B/HLA-A*24:02/β2m complex, which reveals the basis for antigen-specific recognition through interactions with CAR complementarity-determining regions (CDRs). The PC-CAR adopts a diagonal docking mode, where interactions with both conserved and polymorphic HLA framework residues permit recognition of multiple HLA allotypes from the A9 serological cross-reactivity group, covering a combined American population frequency of up to 25.2%. Comprehensive characterization using biochemical binding assays, molecular dynamics simulations, and structural and functional analyses demonstrate that high-affinity PC-CAR recognition of cross-reactive pHLAs necessitates the presentation of a specific peptide backbone, where subtle structural adaptations of the peptide are critical for high-affinity complex formation and CAR-T cell killing. Our results provide a molecular blueprint for engineering CARs with optimal recognition of tumor-associated antigens in the context of different HLAs, while minimizing cross-reactivity with self-epitopes.

The polymorphic nature and intrinsic instability of class I major histocompatibility complex (MHC-I) and MHC-like molecules loaded with suboptimal peptides, metabolites, or glycolipids presents a fundamental challenge for identifying disease-relevant antigens and antigen-specific T cell receptors (TCRs), hindering the development of autologous therapeutics. Here, we leverage the positive allosteric coupling between the peptide and light chain (β2microglobulin, β2m) subunits for binding to the MHC-I heavy chain (HC) through an engineered disulfide bond bridging conserved epitopes across the HC/β2m interface, to generate conformationally stable, open MHC-I molecules. Biophysical characterization shows that open MHC-I molecules are properly folded protein complexes of enhanced thermal stability compared to the wild type, when loaded with low- to intermediate-affinity peptides. Using solution NMR, we characterize the effects of the disulfide bond on the conformation and dynamics of the MHC-I structure, ranging from local changes in β2m interacting sites of the peptide binding groove to long-range effects on the α2-1helix and α3domain. The interchain disulfide bond stabilizes empty MHC-I molecules in a peptide-receptive, open conformation to promote peptide exchange across multiple human leucocyte antigen (HLA) allotypes, covering representatives from five HLA-A, six HLA-B supertypes, and oligomorphic HLA-Ib molecules. Our structural design, combined with conditional β-peptide ligands, provides a universal platform for generating ready-to-load MHC-I systems of enhanced stability, enabling a range of approaches to screen antigenic epitope libraries and probe polyclonal TCR repertoires in the context of highly polymorphic HLA-I allotypes, as well as oligomorphic nonclassical molecules.Significance StatementWe outline a structure-guided approach for generating conformationally stable, open MHC-I molecules with enhanced ligand exchange kinetics spanning five HLA-A, all HLA-B supertypes, and oligomorphic HLA-Ib allotypes. We present direct evidence of positive allosteric cooperativity between peptide binding and β2m association with the heavy chain by solution NMR and HDX-MS spectroscopy. We demonstrate that covalently linked β2m serves as a conformational chaperone to stabilize empty MHC-I molecules in a peptide-receptive state, by inducing an open conformation and preventing intrinsically unstable heterodimers from irreversible aggregation. Our study provides structural and biophysical insights into the conformational properties of MHC-I ternary complexes, which can be further applied to improve the design of ultra-stable, universal ligand exchange systems in a pan-HLA allelic setting.

Organocatalysis inside of a self-assembled supramolecular host provides access to Diels–Alder cyclizations of cinnamaldehydes.

The transition metal-catalyzed Mizoroki–Heck reaction is a powerful method to synthesize C–C bonds, allowing access to several important pharmaceuticals.

Immunological chaperones tapasin and TAP binding protein, related (TAPBPR) play key roles in antigenic peptide optimization and quality control of nascent class I major histocompatibility complex (MHC-I) molecules. The polymorphic nature of MHC-I proteins leads to a range of allelic dependencies on chaperones for assembly and cell-surface expression, limiting chaperone-mediated peptide exchange to a restricted set of human leukocyte antigen (HLA) allotypes. Here, we demonstrate and characterize xeno interactions between a chicken TAPBPR ortholog and a complementary repertoire of HLA allotypes, relative to its human counterpart. We find that TAPBPR orthologs recognize empty MHC-I with broader allele specificity and facilitate peptide exchange by maintaining a reservoir of receptive molecules. Deep mutational scanning of human TAPBPR further identifies gain-of-function mutants, resembling the chicken sequence, which can enhance HLA-A*01:01 expression in situ and promote peptide exchange in vitro. These results highlight that polymorphic sites on MHC-I and chaperone surfaces can be engineered to manipulate their interactions, enabling chaperone-mediated peptide exchange on disease-relevant HLA alleles.

Free or unfunctionalized benzylamines are well known to participate in C–H activation in the presence of palladium salts. Despite the ease with which these complexes can be activated, subsequent functionalization of the dimeric cyclometalates can be challenging. We demonstrate herein a free primary amine based C–H activation/functionalization protocol that allows for the ortho-C–H chlorination and bromination of unprotected benzylamines. We also demonstrate how use of fluorine-based oxidants gives rise to a unique acetoxylation/­cyclization owing to the nucleophilicity of the free primary amine directing group.

Site-specific hydrogen/deuterium exchange is an important method to access deuterated compounds for chemical and biological studies. Herein is reported the first method for the regioselective α-deuteration of enals and enones. The transformation features D2O and AcOD as deuterium sources and amines as organocatalysts. The deuteration strategy is scalable and works on enals with a variety of substituted arene or heterocycle motifs as well as enones. The method has been applied to the synthesis of deuterated drug precursors.

Chikungunya virus (CHIKV) and Zika virus (ZIKV) are arthropod-borne viruses transmitted mainly by Aedes aegypti mosquitoes. These viruses have become endemic in large parts of North, Central, and South America. Arboviruses persistently infect mosquitoes throughout their life span and become infectious (i.e., expectorate infectious virus in saliva) after a period of time called the extrinsic incubation period (EIP). The duration of this infectiousness, however, is not well characterized. This is an important shortcoming because many epidemiological models assume that mosquitoes continue to be infectious for the duration of their life span. To define the duration of infectiousness for CHIKV and ZIKV, mosquitoes were infected orally with these viruses. Every 2 days, legs/wings, midguts, salivary glands, and saliva were collected from 30 to 60 mosquitoes and viral load measured. In CHIKV-infected mosquitoes, infectious virus in saliva peaked early (2-4 dpi), and then decreased rapidly and was rarely observed after 10 dpi. Viral RNA in infected tissues also decreased after the initial peak (4-8 dpi) but did so much less drastically. In ZIKV-infected mosquitoes, the infectious virus in saliva peaked at 12-14 dpi and dropped off only slightly after 14 dpi. In infected tissues, viral RNA increased early during infection, and then plateaued after 6-10 days. Our findings suggest that significant variation exists in the duration of the infectious period for arboviruses that is in part influenced by virus clearance from expectorated saliva.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in 2019 and has become a major global pathogen in an astonishingly short period of time. The emergence of SARS-CoV-2 has been notable due to its impacts on residents in long-term care facilities (LTCFs). LTCF residents tend to possess several risk factors for severe outcomes of SARS-CoV-2 infection, including advanced age and the presence of comorbidities. Indeed, residents of LTCFs represent approximately 40% of SARS-CoV-2 deaths in the United States. Few studies have focused on the prevalence and transmission dynamics of SARS-CoV-2 among LTCF staff during the early months of the pandemic, prior to mandated surveillance testing. To assess the prevalence and incidence of SARS-CoV-2 among LTCF staff, characterize the extent of asymptomatic infections, and investigate the genomic epidemiology of the virus within these settings, we sampled staff for 8 to 11 weeks at six LTCFs with nasopharyngeal swabs from March through June of 2020. We determined the presence and levels of viral RNA and infectious virus and sequenced 54 nearly complete genomes. Our data revealed that over 50% of infections were asymptomatic/mildly symptomatic and that there was a strongly significant relationship between viral RNA (vRNA) and infectious virus, prolonged infections, and persistent vRNA (4+ weeks) in a subset of individuals, and declining incidence over time. Our data suggest that asymptomatic SARS-CoV-2-infected LTCF staff contributed to virus persistence and transmission within the workplace during the early pandemic period. Genetic epidemiology data generated from samples collected during this period support that SARS-CoV-2 was commonly spread between staff within an LTCF and that multiple-introduction events were less common. IMPORTANCE Our work comprises unique data on the characteristics of SARS-CoV-2 dynamics among staff working at LTCFs in the early months of the SARS-CoV-2 pandemic prior to mandated staff surveillance testing. During this time period, LTCF residents were largely sheltering-in-place. Given that staff were able to leave and return daily and could therefore be a continued source of imported or exported infection, we performed weekly SARS-CoV-2 PCR on nasal swab samples collected from this population. There are limited data from the early months of the pandemic comprising longitudinal surveillance of staff at LTCFs. Our data reveal the surprisingly high level of asymptomatic/presymptomatic infections within this cohort during the early months of the pandemic and show genetic epidemiological analyses that add novel insights into both the origin and transmission of SARS-CoV-2 within LTCFs.

Arthropod-borne viruses (arboviruses) require replication across a wide range of temperatures to perpetuate. While vertebrate hosts tend to maintain temperatures of approximately 37°C—40°C, arthropods are subject to ambient temperatures which can have a daily fluctuation of > 10°C. Temperatures impact vector competence, extrinsic incubation period, and mosquito survival unimodally, with optimal conditions occurring at some intermediate temperature. In addition, the mean and range of daily temperature fluctuations influence arbovirus perpetuation and vector competence. The impact of temperature on arbovirus genetic diversity during systemic mosquito infection, however, is poorly understood. Therefore, we determined how constant extrinsic incubation temperatures of 25°C, 28°C, 32°C, and 35°C control Zika virus (ZIKV) vector competence and population dynamics within Aedes aegypti and Aedes albopictus mosquitoes. We also examined fluctuating temperatures which better mimic field conditions in the tropics. We found that vector competence varied in a unimodal manner for constant temperatures peaking between 28°C and 32°C for both Aedes species. Transmission peaked at 10 days post-infection for Aedes aegypti and 14 days for Aedes albopictus. Conversely, fluctuating temperature decreased vector competence. Using RNA-seq to characterize ZIKV population structure, we identified that temperature alters the selective environment in unexpected ways. During mosquito infection, constant temperatures more often elicited positive selection whereas fluctuating temperatures led to strong purifying selection in both Aedes species. These findings demonstrate that temperature has multiple impacts on ZIKV biology, including major effects on the selective environment within mosquitoes., Author summary Arthropod-borne viruses (arboviruses) have emerged in recent decades due to complex factors that include increases in international travel and trade, the breakdown of public health infrastructure, land use changes, and many others. Climate change also has the potential to shift the geographical ranges of arthropod vectors, consequently increasing the global risk of arbovirus infection. Changing temperatures may alter the virus-host interaction, ultimately resulting in the emergence of new viruses and virus genotypes in new areas. Therefore, we sought to characterize how temperature (both constant and fluctuating) alters the ability of Aedes aegypti and Aedes albopictus to transmit Zika virus, and how it influences virus populations within mosquitoes. We found that intermediate temperatures maximize virus transmission compared to more extreme and fluctuating temperatures. Constant temperatures increased positive selection on virus genomes, while fluctuating temperatures strengthened purifying selection. Our studies provide evidence that in addition to altering vector competence, temperature significantly influences natural selection within mosquitoes.

Food allergy education is an ongoing process that must address unique safety concerns and psychosocial challenges at each developmental stage. Families require reliable information that is targeted to specific developmental stages to support the integration of food allergy management into daily life.The purpose of this project was to develop age-specific, evidence-based patient education handouts with practical recommendations for managing and coping with food allergies at different developmental stages.Handout content was based on: (1) practice guidelines for food allergy management; (2) literature addressing psychosocial and educational needs of patients with food allergy and their caregivers; and (3) clinical experience of the project team. Fifty-seven caregivers of patients (aged 0-21 years) with food allergy and 2 young adults with food allergy reviewed a draft of the handouts and completed an online survey to assess handout acceptability and usability and identify areas for improvement. Handouts were revised based on participant feedback.The majority of participants (79%) rated the amount of information in the age-specific handouts as "just right," versus "not enough" (9%) or "too much" information (12%). Sixty-three percent reported that they would be "very likely" to use the handouts as a resource and 35% "somewhat likely." Almost all participants (88%-100% by item) agreed that the handouts used elements of plain language writing and clear communication.Caregivers rated the age-based food allergy education handouts as understandable and useful. We anticipate that these handouts could be used during health care visits and directly accessed online by families.

Methods to catalytically introduce deuterium in synthetically useful yields ortho to a carboxylic acid directing group on arenes typically requires D2 or high catalyst loadings, which makes using these approaches cost prohibitive for large-scale synthesis (equipment and reagent costs respectively). Herein, we present a simplified approach using low catalyst loadings of cationic RhIII and D2O as both deuterium source and solvent and show its application to H/D exchange on various carboxylic acid substrates.

C-C bond formation by transition metal-catalyzed C-H activation has become an important strategy to fabricate new bonds in a rapid fashion. Despite the pharmacological importance of ortho-arylbenzylamines, however, effective ortho-C-C bond formation of free primary and secondary benzylamines using PdII remains an outstanding challenge. Presented herein is a new strategy for constructing ortho-arylated primary and secondary benzylamines mediated by carbon dioxide (CO2). The use of CO2 with Pd is critical to allowing this transformation to proceed under relatively mild conditions, and mechanistic studies indicate that it (CO2) is directly involved in the rate-determining step. Furthermore, the milder temperatures furnish free amine products that can be directly used or elaborated without the need for deprotection. In cases where diarylation is possible, an interesting chelate effect is shown to facilitate selective monoarylation.

The direct difunctionalization of alkenes is an effective way to construct multiple C-C bonds in one-pot using a single functional group. The regioselective dicarbofunctionalization of alkenes is therefore an important area of research to rapidly obtain complex organic molecules. Herein, we report a palladium-catalyzed γ,γ'-diarylation of free alkenyl amines through interrupted chain walking for the synthesis of Z-selective alkenyl amines. Notably, while 1,3-dicarbofunctionalization of allyl groups is well precedented, the present disclosure allows 1,3-dicarbofunctionalization of highly substituted allylamines to give highly Z-selective trisubsubstituted olefin products. This cascade reaction operates via an unprotected amine-directed Mizoroki-Heck (MH) pathway featuring a β-hydride elimination to selectively chain walk to furnish a new terminal olefin which then generates the cis-selective alkenyl amines around the sterically crowded allyl moiety. This operationally simple protocol is applicable to a variety of cyclic, branched, and linear secondary and tertiary alkenylamines, and has a broad substrate scope with regard to the arene coupling partner as well. Mechanistic studies have been performed to help elucidate the mechanism, including the presence of a likely unproductive side C-H activation pathway.

Arthropod-borne viruses (arboviruses) require replication across a wide range of temperatures to perpetuate. While vertebrate hosts tend to maintain temperatures of approximately 37°C - 40°C, arthropods are subject to ambient temperatures which can have a daily fluctuation of > 10°C. Temperatures impact vector competence, extrinsic incubation period, and mosquito survival unimodally, with optimum occurring at some intermediate temperature. In addition, the mean and range of daily temperature fluctuations influence arbovirus perpetuation and vector competence. The impact of temperature on arbovirus genetic diversity during systemic mosquito infection, however, is poorly understood. Therefore, we determined how constant extrinsic incubation temperatures of 25°C, 28°C, 32°C, and 35°C control Zika virus (ZIKV) vector competence and population dynamics withinAedes aegyptiandAedes albopictusmosquitoes. We also examined diurnally fluctuating temperatures which more faithfully mimic field conditions in the tropics. We found that vector competence varied in a unimodal manner for constant temperatures peaking between 28°C and 32°C for bothAedesspecies. Transmission peaked at 10 days post-infection forAedes aegyptiand 14 days forAedes albopictus.The effect of diurnal temperature was distinct and could not have been predicted from constant temperature-derived data. Using RNA-seq to characterize ZIKV population structure, we identified that temperature alters the selective environment in unexpected ways. During mosquito infection, constant temperatures more often elicited positive selection whereas diurnal temperatures led to strong purifying selection in bothAedesspecies. These findings demonstrate that temperature has multiple impacts on ZIKV biology within mosquitoes, including major effects on the selective environment within mosquitoes.Author SummaryArthropod-borne viruses (arboviruses) have emerged in recent decades due to complex factors that include increases in international travel and trade, the breakdown of public health infrastructure, land use changes, and many other factors. Climate change also has the potential to shift the geographical ranges of arthropod vectors, consequently increasing the global risk of arbovirus infection. Changing temperatures may also alter the virus-host interaction, ultimately resulting in the emergence of new viruses and virus genotypes in new areas. Therefore, we sought to characterize how temperature (both constant and fluctuating) alters the ability ofAedes aegyptiandAedes albopictusto transmit Zika virus, and how it influences virus populations within mosquitoes. We found that intermediate temperatures maximize virus transmission compared to more extreme and fluctuating temperatures. Constant temperatures increased positive selection on virus genomes, while fluctuating temperatures strengthened purifying selection. Our studies provide evidence that in addition to altering VC, temperature significantly influences the selective environment within mosquitoes.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in 2019 and has become a major global pathogen in an astonishingly short period of time. The emergence of SARS-CoV-2 has been notable due to its impacts on residents in long-term care facilities (LTCFs). LTCF residents tend to possess several risk factors for severe outcomes of SARS-CoV-2 infection, including advanced age and the presence of comorbidities. Indeed, residents of LTCFs represent approximately 40% of SARS-CoV-2 deaths in the United States. Few studies have focused on the prevalence and transmission dynamics of SARS-CoV-2 among LTCF staff during the early months of the pandemic, prior to mandated surveillance testing. To assess the prevalence and incidence of SARS-CoV-2 among LTCF staff, characterize the extent of asymptomatic infections, and investigate the genomic epidemiology of the virus within these settings, we sampled staff for 8 to 11 weeks at six LTCFs with nasopharyngeal swabs from March through June of 2020. We determined the presence and levels of viral RNA and infectious virus and sequenced 54 nearly complete genomes. Our data revealed that over 50% of infections were asymptomatic/mildly symptomatic and that there was a strongly significant relationship between viral RNA (vRNA) and infectious virus, prolonged infections, and persistent vRNA (4+ weeks) in a subset of individuals, and declining incidence over time. Our data suggest that asymptomatic SARS-CoV-2-infected LTCF staff contributed to virus persistence and transmission within the workplace during the early pandemic period. Genetic epidemiology data generated from samples collected during this period support that SARS-CoV-2 was commonly spread between staff within an LTCF and that multiple-introduction events were less common. IMPORTANCE Our work comprises unique data on the characteristics of SARS-CoV-2 dynamics among staff working at LTCFs in the early months of the SARS-CoV-2 pandemic prior to mandated staff surveillance testing. During this time period, LTCF residents were largely sheltering-in-place. Given that staff were able to leave and return daily and could therefore be a continued source of imported or exported infection, we performed weekly SARS-CoV-2 PCR on nasal swab samples collected from this population. There are limited data from the early months of the pandemic comprising longitudinal surveillance of staff at LTCFs. Our data reveal the surprisingly high level of asymptomatic/presymptomatic infections within this cohort during the early months of the pandemic and show genetic epidemiological analyses that add novel insights into both the origin and transmission of SARS-CoV-2 within LTCFs.

In the wake of the COVID-19 pandemic and massive disruptions to daily life in the spring of 2020, in May 2020, the Centers for Disease Control (CDC) released guidance recommendations for schools regarding how to have students attend while adhering to principles of how to reduce the risk of contracting SARS-CoV-2. As part of physical distancing measures, the CDC is recommending that schools who traditionally have had students eat in a cafeteria or common large space instead have children eat their lunch or other meals in the classroom at already physically distanced desks. This has sparked concern for the safety of food-allergic children attending school, and some question of how the new CDC recommendations can coexist with recommendations in the 2013 CDC Voluntary Guidelines on Managing Food Allergy in Schools as well as accommodations that students may be afforded through disability law that may have previously prohibited eating in the classroom. This expert consensus explores the issues related to evidence-based management of food allergy at school, the issues of managing the health of children attending school that are acutely posed by the constraints of an infectious pandemic, and how to harmonize these needs so that all children can attend school with minimal risk from both an infectious and allergic standpoint.

In response to the call for an increased emphasis from the American Chemical Society on including macromolecular studies in the undergraduate curriculum, a supramolecular-themed experiment was designed for undergraduate-level organic laboratory courses that provides a convenient platform to study physical behaviors of supramolecular assemblies. Students synthesize an easily purified resorcin[4]arene and characterize the product of its self-assembly via 1H NMR spectroscopy. These bowl-shaped molecules are noteworthy because of their propensity to self-assemble in organic solution in the presence of trace water or alcohol solvents. Upon self-assembly, the resulting hexamer adopts a well-defined molecular cage structure with a large internal cavity that can be used to explore host:guest chemistry. After completing the experiment, students are expected to gain a better understanding of electrophilic aromatic substitution, 1H NMR spectroscopy, supramolecular chemistry and self-assembly, and molecular recognition.

Background Morgagni hernias are rare congenital diaphragmatic hernias that often do not become clinically significant until adulthood. The purpose of this study was to characterize the preoperative findings and describe surgical outcomes of Morgagni hernia repair based on operative approach. Methods Charts of patients who underwent repair of a Morgagni hernia were retrospectively reviewed from 1987 to 2015. Medical records were reviewed for demographics, symptoms, comorbidities, surgical approach, hospital course, complications, and preoperative imaging. Results Forty-three cases were identified, 23 male and 20 female. Median age was 50.4 years, and median body mass index was 33.1 kg/m2. Most common presenting symptoms were respiratory (35.7%) and gastrointestinal (28.6%). Although 83.3% of cases were newly diagnosed, none required emergent repair. Preoperative imaging demonstrated an average hernia size of 8.2 cm. Surgical approaches included laparotomy (62.8%), laparoscopic (23.3%), and thoracotomy (14%). Primary hernia repair was most common (72%). Comparing laparotomy, thoracotomy, and laparoscopic approaches, mesh repair was more common with laparoscopy (p = 0.005), operative time was shortest with laparotomy (p = 0.029), and hospital length of stay was shortest with laparoscopy (p = 0.024). The most common complication was incisional/port site hernia, with no statistical significance between surgical approaches. There was one Morgagni hernia recurrence. Conclusions Morgagni hernias often present with respiratory and gastrointestinal symptoms and require repair. All cases in our series were repaired electively. Regardless of approach recurrence rate was low (2.3%) and complication rate was similar between laparoscopic, laparotomy, and thoracotomy. Given the shorter length of stay with similar recurrence rates, a laparoscopic approach is a viable option for repair of Morgagni hernia.

An efficient method has been developed for the synthesis of seven-membered biaryl lactams involving Pd-catalyzed, native amine-directed, ortho-arylation of benzylamines followed by in situ lactamiz...

BACKGROUND: Little is known about the psychosocial impact of food-protein induced enterocolitis syndrome (FPIES). OBJECTIVE: To characterize quality of life, stress, worry, anxiety and self-efficacy in caregivers of children with FPIES and affected children, and determine risk factors for increased psychosocial burden. METHODS: Surveys completed by caregiver-members of the International FPIES Association at a conference (n=42) and online (n=368) were analyzed. RESULTS: There was significant burden, stress, worry and anxiety among caregivers. There was positive correlation among Food Allergy Quality of Life-Parental Burden, Perceived Stress Scale-10, Penn State Worry Questionnaire, and Beck Anxiety Inventory scores, and these were negatively associated with Food Allergy Self-Efficacy for Parents (FASE-P) scores. Lower income was associated with poorer caregiver health-related quality of life (HRQoL) (p=0.039), and lower FASE-P (p=0.028). Greater number of food groups avoided correlated moderately with poorer HRQoL (r=0.386, p

Elaborating amines via C–H functionalization has been an important area of research over the past decade but has generally relied on an added directing group or sterically hindered amine approach. Since free-amine-directed C(sp3)–H activation is still primarily limited to cyclization reactions and to improve the sustainability and reaction scope of amine-based C–H activation, we present a strategy using CO2 in the form of dry ice that facilitates intermolecular C–H arylation. This methodology has been used to enable an operationally simple procedure whereby 1° and 2° aliphatic amines can be arylated selectively at their γ-C–H positions. In addition to potentially serving as a directing group, CO2 has also been demonstrated to curtail the oxidation of sensitive amine substrates.

Food challenges are the criterion standard for establishing the presence or absence of food allergy. However, they remain underused because of their resource-intensive nature, inadequate reimbursement, and concern for the risk of anaphylaxis. Here, we review indications for performing food challenges, including scenarios of uncertain diagnosis, quality-of-life effects following food challenges, and the impact on office practice including coding and reimbursement issues. Demand for food challenges is likely to increase and allergists should be capable of providing this service to their patients when indicated.

Tertiary amines are poor directing groups for C(sp3)–H activation using Pdii catalysts due to favourable β-hydride elimination pathways. Now, an N-acetyl amino acid ligand is shown to shut down this deleterious pathway, enabling facile arylation of a highly medicinally relevant group of compounds.

We report a Rh(I)-catalyzed site-selective coupling between ketone β-C(sp3)–H bonds and aliphatic alkynes using an in situ-installed directing group. Upon hydrogenation or hydration, various β-alkylation or β-aldol products of the ketones are obtained with broad functional group tolerance. Mechanistic investigations support the involvement of a Rh–H intermediate through oxidative addition of Rh(I) into the β-C–H bonds. Thus, to the best of our knowledge, this transformation represents the first example of catalytic couplings between unsaturated hydrocarbons and unactivated aliphatic C–H bonds via a metal–hydride pathway.

Background SARS-CoV-2 emerged in 2019 and has become a major global pathogen. Its emergence is notable due to its impacts on individuals residing within long term care facilities (LTCFs) such as rehabilitation centers and nursing homes. LTCF residents tend to possess several risk factors for more severe SARS-CoV-2 outcomes, including advanced age and multiple comorbidities. Indeed, residents of LTCFs represent approximately 40% of SARS-CoV- 2 deaths in the United States. Methods To assess the prevalence and incidence of SARS-CoV-2 among LTCF workers, determine the extent of asymptomatic SARS-CoV-2 infection, and provide information on the genomic epidemiology of the virus within these unique care settings, we collected nasopharyngeal swabs from workers for 8-11 weeks at six Colorado LTCFs, determined the presence and level of viral RNA and infectious virus within these samples, and sequenced 54 nearly complete genomes. Findings Our data reveal a strikingly high degree of asymptomatic/mildly symptomatic infection, a strong correlation between viral RNA and infectious virus, prolonged infections and persistent RNA in a subset of individuals, and declining incidence over time. Interpretation Our data suggest that asymptomatic SARS-CoV-2 infected individuals contribute to virus persistence and transmission within the workplace, due to high levels of virus. Genetic epidemiology revealed that SARS-CoV-2 likely spreads between staff within an LTCF. Funding Colorado State University Colleges of Health and Human Sciences, Veterinary Medicine and Biomedical Sciences, Natural Sciences, and Walter Scott, Jr. College of Engineering, the Columbine Health Systems Center for Healthy Aging, and the National Institute of Allergy and Infectious Diseases. Research in Context Evidence before this study We searched PubMed and Google Scholar on April 15, 2020 for manuscripts published in 2020 with the key words “SARS-CoV-2 OR COVID-19 AND Long- Term Care Facility AND Surveillance OR Screening. We did not restrict our search to the English language. Our search retrieved two reports of original research. The relevant publications described transmission and course of infection among residents in LTCFs. Of particular relevance was that large quantities of SARS-CoV-2 viral RNA could be detected in asymptomatic, presymptomatic and symptomatic residents, providing early evidence of the heterogeneity of infection characteristics among residents at LTCFs. A significant number of LTCF residents were presymptomatic with symptoms emerging 7 days after initial detection of viral RNA, indicating a longer than expected latency period. Therefore, symptomatic screening for early detection and resultant mitigation response was likely to be ineffective in preventing transmission among residents of LTCFs. There were no reports involving longitudinal surveillance testing of LTCF staff. Added value of this study While prior studies reported results of facility-wide (residents and staff) testing for SARS-CoV-2 and describe transmission dynamics among residents of LTCFs, no prior data was available describing the longitudinal characteristics of SARS-CoV-2 dynamics among staff working at LTCFs during a time period where “shelter-in-place” public guidance was in effect. During this time period, LTCF residents were largely isolated, however staff (those with both direct care and those without direct contact) were permitted to leave and return to work daily. We were therefore interested in this broad staff cohort specifically because they represent a significant and ongoing potential source of transmission within LTCFs. RT-qPCR testing for SARS-CoV-2 was performed weekly on 544 staff in six LTCFs over an 8-11-week period. Symptom data were collected and site-specific prevalence at study onset and incidence rate over time were calculated to explore the influence of identifying and removing asymptomatic SARS-CoV-2-infected individuals from the workplace. Implications of all the available evidence Our results document a surprising degree of asymptomatic/mildly symptomatic infection among apparently healthy staff, and extreme variation in SARS-CoV-2 prevalence and incidence among staff between different facilities. Plaque assay revealed a strong relationship between vRNA and infectious virus in nasopharyngeal swab material, indicating the asymptomatic or mildly symptomatic individuals are infectious. Moreover, phylogenetic analysis of SARS-CoV-2 sequences collected from LTCF staff suggest that the predominant transmission pattern is between staff members within facilities, and that individual unrelated community import events are less common. Finally, decreasing prevalence over time within facilities where longitudinal surveillance testing was performed suggests that identifying and isolating positive staff may serve as part of an effective mitigation program to prevent or curtail transmission among staff within LTCFs.

Oral food challenges are an integral part of an allergist's practice and are used to evaluate the presence or absence of allergic reactivity to foods. A work group within the Adverse Reactions to Foods Committee of the American Academy of Allergy, Asthma & Immunology was formed to update a previously published oral food challenge report. The intention of this document was to supplement the previous publication with additional focus on safety, treatment of IgE-mediated allergic reactions, guidance for challenges in infants and adults, psychosocial considerations for children and families participating in an oral food challenge, specific guidance for baked milk or baked egg challenges, masking agents and validated blinding recipes for common food allergens, and recommendations for conducting and interpreting challenges in patients with suspected food protein–induced enterocolitis syndrome. Tables and figures within the report and an extensive online appendix detail age-specific portion sizes, appropriate timing for antihistamine discontinuation, serum and skin test result interpretation, written consents, and instructional handouts that may be used in clinical practice.

BACKGROUND: Food-protein induced enterocolitis syndrome (FPIES) is a non-IgE-mediated gastrointestinal food allergy. There is little known about demographics, food triggers and risk factors for FPIES. OBJECTIVE: We characterized demographics, food triggers, risk factors, and management in a cohort of 441 children with FPIES. METHODS: We retrospectively analyzed surveys completed by 410 caregiver-members of the International FPIES Association (I-FPIES), both at a conference for families affected by FPIES and online. RESULTS: The majority of children were female (50.7%), white (86.2%), and atopic (54.8%), with median age two years (range two months-19 years). The most common food groups avoided were grains (60.0%), cow’s milk (52.4%), vegetables (42.7%), and fruits (38.0%). Avocado was the most commonly avoided fruit. Avoiding avocado was associated with increased likelihood of avoiding banana (P< 0.001). 69.4% avoided at least two food groups due to FPIES. 20.3% had a first-degree relative with FPIES. Having a first-degree relative with FPIES was associated with increased likelihood of avoiding multiple food groups (P=0.035). CONCLUSIONS: Grains was the most common food group avoided, consistent with recent literature. Avocado avoidance was higher than previously reported, and this is the first report of an association between avocado and banana avoidance in FPIES. Avoiding multiple food groups due to FPIES was more common than previously reported. A large proportion of children in our cohort had first-degree relatives with FPIES and, furthermore, having a first-degree relative with FPIES was significantly associated with the affected child avoiding multiple food groups.

Methods to catalytically introduce deuterium in synthetically useful yields

This cross-sectional study evaluates self-reported behaviors and cases of SARS-CoV-2 infection among essential in-person employees during the first 6 months of the COVID-19 pandemic at a US institution of higher education., Key Points Question What was the prevalence of SARS-CoV-2 infection and associated protective behaviors among essential employees at an institution of higher education during the first 6 months of the COVID-19 pandemic in the US? Findings In this cross-sectional study of 508 essential employees, no cases of SARS-CoV-2 infection were verified by quantitative reverse transcriptase–polymerase chain reaction, and only 2 participants had measurable seroreactive IgG antibodies. High levels of handwashing and mask wearing were reported at work and outside work, and social distancing was reported significantly less often at work than outside work. Meaning The findings suggest that compliance with protective behaviors both at work and outside work may be commensurate with the safe operation of complex work environments during a pandemic., Importance Detailed analysis of infection rates paired with behavioral and employee-reported risk factors is vital to understanding how transmission of SARS-CoV-2 infection may be exacerbated or mitigated in the workplace. Institutions of higher education are heterogeneous work units that supported continued in-person employment during the COVID-19 pandemic, providing a test site for occupational health evaluation. Objective To evaluate the association between self-reported protective behaviors and prevalence of SARS-CoV-2 infection among essential in-person employees during the first 6 months of the COVID-19 pandemic in the US. Design, Setting, and Participants This cross-sectional study was conducted from July 13 to September 2, 2020, at an institution of higher education in Fort Collins, Colorado. Employees 18 years or older without symptoms of COVID-19 who identified as essential in-person workers during the first 6 months of the pandemic were included. Participants completed a survey, and blood and nasal swab samples were collected to assess active SARS-CoV-2 infection via quantitative reverse transcriptase–polymerase chain reaction (qRT-PCR) and past infection by serologic testing. Exposure Self-reported practice of protective behaviors against COVID-19 according to public health guidelines provided to employees. Main Outcomes and Measures Prevalence of current SARS-CoV-2 infection detected by qRT-PCR or previous SARS-CoV-2 infection detected by an IgG SARS-CoV-2 testing platform. The frequency of protective behavior practices and essential workers’ concerns regarding contracting COVID-19 and exposing others were measured based on survey responses. Results Among 508 participants (305 [60.0%] women, 451 [88.8%] non-Hispanic White individuals; mean [SD] age, 41.1 [12.5] years), there were no qRT-PCR positive test results, and only 2 participants (0.4%) had seroreactive IgG antibodies. Handwashing and mask wearing were reported frequently both at work (480 [94.7%] and 496 [97.8%] participants, respectively) and outside work (465 [91.5%] and 481 [94.7%] participants, respectively). Social distancing was reported less frequently at work (403 [79.5%]) than outside work (465 [91.5%]) (P

Metal-organic frameworks (MOFs) show promise for catalysis applications due to their porosity, high internal surface area, and structural adaptability. Typical acetalization reactions of aldehydes require elevated temperatures and excess alcohol to drive the reactions to completion. In this current work, MOF-808 is used as a heterogeneous catalyst for acetylation of aldehydes in methanol using a mild photothermal process. Optimized conditions gave 72% yield of 2-(dimethoxymethyl)naphthalene in the presence of 10 mol% MOF-808 at 45 °C using only a fluorescent lamp. MOF-808 can be recycled up to 5 times with no loss in catalytic activity. A proof-of-principle substrate scope demonstrates the potential utility for aromatic and aliphatic substrates.