Quality and fertilizing ability of frozen-thawed porcine sperm separated using a migration sedimentation method.

We evaluated the quality and fertilizing ability of frozen-thawed porcine sperm that were selected using a commercially available device (MIGLIS, Menicon Life Science) consisting of three parts: an outer lid, an inner lid, and a tube. Firstly, to determine an adequate concentration of caffeine for separation, frozen-thawed sperm were incubated with different concentrations of caffeine (0, 1, 2.5, 5, and 10 mM) in a MIGLIS device. To determine the appropriate incubation time for separating sperm in the MIGLIS device, frozen-thawed sperm were incubated with 2.5 mM caffeine for 5, 10, 15, or 20 min. To evaluate the fertilization and embryo development of oocytes fertilized with frozen-thawed sperm separated into two regions (outer and inner) in the MIGLIS device, the separated sperm from the three boars was used to fertilize in vitro-matured oocytes and cultured in vitro for 7 days. Sperm quality parameters of sperm collected from the inner tube after incubation with 2.5 mM caffeine were superior to sperm incubated without caffeine. Moreover, sperm collected from the inner tube after incubation for 10 min had a higher progressive motility. The rate of blastocyst produced from spermatozoa collected from the inner tube after incubation with 2.5 mM caffeine for 10 min significantly increased compared to that produced from spermatozoa from the outer tube, regardless of the boar. In conclusion, sperm sorting using the MIGLIS device may be useful for separating high-quality sperm after incubation with 2.5 mM caffeine for 10 min to improve blastocyst formation.

Severe Pneumonia Caused by Respiratory Syncytial Virus and Adenovirus in Children from 2 to 24 Months at Children's Hospital 1 in Ho Chi Minh City, Vietnam.

In Vietnam, due to the lack of facilities to detect respiratory viruses from patients' specimens, there are only a few studies on the detection of viral pathogens causing pneumonia in children, especially respiratory syncytial virus (RSV) and adenovirus (Adv). Here, we performed a cross-sectional descriptive prospective study on 138 children patients from 2 to 24 months old diagnosed with severe pneumonia hospitalized at the Respiratory Department of Children's Hospital 1 from November 2021 to August 2022. The number of patients selected in this study was based on the formula n = ([Z(1 - α/2)]2 × P [1 - P])/d2, with α = 0.05, p = 0.5, and d = 9%, and the sampling technique was convenient sampling until the sample size was met. A rapid test was used to detect RSV and Adv from the nasopharyngeal swabs and was conducted immediately after the patient's hospitalization. Laboratory tests were performed, medical history interviews were conducted, and nasotracheal aspirates were collected for multiplex real-time PCR (MPL-rPCR) to detect viral and bacterial pathogens. The results of the rapid test and the MPL-rPCR in the detection of both pathogens were the same at 31.9% (44/138) for RSV and 8.7% (7/138) for Adv, respectively. Using MPL-rPCR, the detection rate was 21% (29/138) for bacterial pathogens, 68.8% (95/138) for bacterial-viral co-infections, and 6.5% (9/138) for viral pathogens. The results showed few distinctive traits between RSV-associated and Adv-associated groups, and the Adv group children were more prone to bacterial infection than those in the RSV group. In addition, the Adv group experienced a longer duration of treatment and a higher frequency of re-hospitalizations compared to the RSV group. A total of 100% of Adv infections were co-infected with bacteria, while 81.82% of RSV co-infected with bacterial pathogens (p = 0.000009). This study might be one of the few conducted in Vietnam aimed at identifying viral pathogens causing severe pneumonia in children.

Diamond surface functionalization via visible light-driven C-H activation for nanoscale quantum sensing.

Nitrogen-vacancy (NV) centers in diamond are a promising platform for nanoscale NMR sensing. Despite significant progress toward using NV centers to detect and localize nuclear spins down to the single spin level, NV-based spectroscopy of individual, intact, arbitrary target molecules remains elusive. Such sensing requires that target molecules are immobilized within nanometers of NV centers with long spin coherence. The inert nature of diamond typically requires harsh functionalization techniques such as thermal annealing or plasma processing, limiting the scope of functional groups that can be attached to the surface. Solution-phase chemical methods can be readily generalized to install diverse functional groups, but they have not been widely explored for single-crystal diamond surfaces. Moreover, realizing shallow NV centers with long spin coherence times requires highly ordered single-crystal surfaces, and solution-phase functionalization has not yet been shown with such demanding conditions. In this work, we report a versatile strategy to directly functionalize C-H bonds on single-crystal diamond surfaces under ambient conditions using visible light, forming C-F, C-Cl, C-S, and C-N bonds at the surface. This method is compatible with NV centers within 10 nm of the surface with spin coherence times comparable to the state of the art. As a proof-of-principle demonstration, we use shallow ensembles of NV centers to detect nuclear spins from surface-bound functional groups. Our approach to surface functionalization opens the door to deploying NV centers as a tool for chemical sensing and single-molecule spectroscopy.

Effects of ergothioneine supplementation on the quality of liquid-preserved and frozen-thawed boar semen.

This study examined the effects of ergothioneine (EGT) supplementation as an antioxidant on the quality of boar spermatozoa when using liquid and frozen preservation methods. In the first experiment, boar semen was preserved in an extender supplemented with 0, 50, 100 and 200 µM EGT, at 15 °C, part of the samples for one and another part for three weeks. In comparison with the control (without EGT), EGT supplementation at 100 µM significantly increased the percentage of total motility of spermatozoa that were preserved as a liquid both for one and three weeks (P < 0.05). EGT supplementation did not affect the quality of preserved spermatozoa, irrespective of the EGT concentration. In the second experiment, semen was frozen and thawed in the freezing extender supplemented with 0, 50, 100 and 200 µM EGT. In comparison with the control, the 100 µM EGT supplementation significantly increased the percentages of total and progressive motility of frozen-thawed spermatozoa (P < 0.05). EGT (100 µM) supplementation did not affect the viability, the plasma membrane integrity, or the acrosomal integrity of frozen-thawed spermatozoa. These findings indicate that supplementing extenders with 100 µM EGT may improve the motility of boar sperm in both liquid and freezing preservation methods.

Development of porcine embryos cultured in media irradiated with ultraviolet-C.

Sterilization of the culture medium using ultraviolet (UV)-C reduces the potential adverse effects of microorganisms and allows for long-term use. In the present study, we investigated the effects of a medium directly irradiated with UV-C prior to in vitro culture on the development and quality of porcine in vitro-fertilized embryos and the free amino acid composition of the culture media. The culture media (porcine zygote medium [PZM-5] and porcine blastocyst medium [PBM]) were irradiated with UV-C at 228 and 260 nm for 1 and 3 days, respectively. Next, the culture media were irradiated with UV-C at 228 nm for 3, 7, or 14 days. After in vitro fertilization, the embryos were cultured in the UV-C-irradiated media for 7 days. Free amino acid levels in culture media irradiated with 228 and 260 nm UV-C for 3 days were analysed. The blastocyst formation rate of embryos cultured in media irradiated with 260 nm UV-C for 3 days was significantly lower than that of embryos cultured in non-irradiated control media. However, 228 nm UV-C irradiation for up to 14 days did not affect blastocyst formation rates and quality in the resulting blastocysts. Moreover, 260 nm UV-C irradiation significantly increased the taurine concentration in both culture media and decreased methionine concentration in the PBM. In conclusion, UV-C irradiation at 228 nm before in vitro culture had no detrimental effects on embryonic development. However, 260 nm UV-C irradiation decreased embryo development and altered the composition of free amino acids in the medium.

Selection of spermatozoa with high motility and quality from bovine frozen-thawed semen using the centrifuge-free device.

This study aimed to assess the potential of the centrifuge-free commercial device (MIGLIS®) in selecting functional frozen-thawed bovine sperm by migration-sedimentation, its effect on embryo development, and compare the potential with that of centrifugation-based techniques, including washing and Percoll density gradient centrifugation (DGC). In experiment 1, different dilutions (1.5×, 2×, and 3×) of frozen-thawed spermatozoa were assessed to identify the adequate one for the MIGLIS method. In experiment 2, the recovery rates, quality, and reactive oxygen species (ROS) concentrations of the spermatozoa selected using MIGLIS, washing, and Percoll DGC were compared. In experiment 3, the resultant in vitro fertilised embryos from spermatozoa selected using the three methods were evaluated for blastocyst formation rates and intracellular ROS concentrations at the 2-4 cell stage. The intracellular ROS concentrations were investigated using 2', 7'-dichlorodihydrofluorescein diacetate staining. Using the MIGLIS device, significantly more spermatozoa were recovered at 2× dilution compared with the other dilution ratio, but the motility was not affected by the dilution ratio. On the selection of spermatozoa using the three methods, employing MIGLIS decreased the recovery rates. However, the MIGLIS method increased motility, viability, and acrosome integrity rates compared to those in spermatozoa from the other methods. The ROS concentration of spermatozoa in the MIGLIS method was significantly lower than that in the washing method. Nevertheless, blastocyst formation rates were similar among the three methods, but the ROS concentration of early-stage embryos produced using MIGLIS was significantly lower than those produced using Percoll DGC. In conclusion, the MIGLIS method has the potential to select functional, high-quality frozen-thawed bovine spermatozoa.

Evaluating M2BPGi as a Marker for Liver Fibrosis in Patients with Chronic Hepatitis B.

BACKGROUND: The accurate evaluation of liver fibrosis is crucial for the treatment and follow up of chronic hepatitis B (CHB) patients. AIM: We examined the efficiency of serum Mac-2 Binding Protein Glycosylation isomer (M2BPGi) in diagnosing liver fibrosis stages in CHB patients. METHODS: A cross-sectional study was conducted on 177 adult CHB patients visiting the University Medical Center Ho Chi Minh City, Vietnam between October 2019 and December 2021. M2BPGi, ARFI, APRI, and FIB-4 were tested against FibroScan® for sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). The optimal M2BPGi cut-off values were identified based on the area under the receiver operating characteristic (AUROC) curve. RESULTS: There was a strong agreement between M2BPGi and FibroScan® (r = 0.77, P < 0.001). The optimal M2BPGi cut-off index (C.O.I) for detecting significant fibrosis (F ≥ 2) was 0.79 with an AUROC of 0.77, 67.3% sensitivity, 70% specificity, 60.6% NPV, and 75.3% PPV. Compared with APRI (61%) and FIB-4 (47%), M2BPGi had the greatest sensitivity for diagnosing F ≥ 2. M2BPGi combined with APRI yielded highest diagnosis performance for F ≥ 2 with an AUROC of 0.87. The optimal cut-off index of M2BPGi for diagnosing cirrhosis (F4) was 1.3 with an AUROC of 0.91, 88% sensitivity, 87.4% specificity, 97% NPV, and 61% PPV. The AUROC of M2BPGi for diagnosing F4 was comparable to that of ARFI (0.93). CONCLUSIONS: With cut-off values of 0.79 C.O.I and 1.3 C.O.I, M2BPGi could be an effective method for diagnosing significant fibrosis and cirrhosis in CHB patients, respectively.

Histidine-rich protein II nanoparticle delivery of heme iron load drives endothelial inflammation in cerebral malaria.

Histidine-rich protein II (HRPII) is secreted by Plasmodium falciparum during the blood stage of malaria infection. High plasma levels of HRPII are associated with cerebral malaria, a severe and highly fatal complication of malaria. HRPII has been shown to induce vascular leakage, the hallmark of cerebral malaria, in blood-brain barrier (BBB) and animal models. We have discovered an important mechanism for BBB disruption that is driven by unique features of HRPII. By characterizing serum from infected patients and HRPII produced by P. falciparum parasites in culture, we found that HRPII exists in large multimeric particles of 14 polypeptides that are richly laden with up to 700 hemes per particle. Heme loading of HRPII is required for efficient binding and internalization via caveolin-mediated endocytosis in hCMEC/D3 cerebral microvascular endothelial cells. Upon acidification of endolysosomes, two-thirds of the hemes are released from acid-labile binding sites and metabolized by heme oxygenase 1, generating ferric iron and reactive oxygen species. Subsequent activation of the NLRP3 inflammasome and IL-1ß secretion resulted in endothelial leakage. Inhibition of these pathways with heme sequestration, iron chelation, or anti-inflammatory drugs protected the integrity of the BBB culture model from HRPII:heme. Increased cerebral vascular permeability was seen after injection of young mice with heme-loaded HRPII (HRPII:heme) but not with heme-depleted HRPII. We propose that during severe malaria infection, HRPII:heme nanoparticles in the bloodstream deliver an overwhelming iron load to endothelial cells to cause vascular inflammation and edema. Disrupting this process is an opportunity for targeted adjunctive therapies to reduce the morbidity and mortality of cerebral malaria.

Chemical Recycling of Thiol Epoxy Thermosets via Light-Driven C-C Bond Cleavage.

Epoxy thermosets are high-volume materials that play a central role in a wide range of engineering applications; however, technologies to recycle these polymers remain rare. Here, we present a catalytic, light-driven method that enables chemical recycling of industrially relevant thiol epoxy thermosets to their original monomer at ambient temperature. This strategy relies on the proton-coupled electron transfer (PCET) activation of hydroxy groups within the polymer network to generate key alkoxy radicals that promote the fragmentation of the polymer through C-C bond ß-scission. The method fully depolymerizes insoluble thiol epoxy thermosets into well-defined mixtures of small-molecule products, which can collectively be converted into the original monomer via a one-step dealkylation process. Notably, this process is selective and efficient even in the presence of other commodity plastics and additives commonly found in commercial applications. These results constitute an important step toward making epoxy thermosets recyclable and more generally exemplify the potential of PCET to offer a more sustainable end-of-life for a diverse array of commercial plastics.

Maturation and substrate processing topography of the Plasmodium falciparum invasion/egress protease plasmepsin X.

The malaria parasite Plasmodium invades a host erythrocyte, multiplies within a parasitophorous vacuole (PV) and then ruptures the PV and erythrocyte membranes in a process known as egress. Both egress and invasion are controlled by effector proteins discharged from specialized secretory organelles. The aspartic protease plasmepsin X (PM X) regulates activity for many of these effectors, but it is unclear how PM X accesses its diverse substrates that reside in different organelles. PM X also autoprocesses to generate different isoforms. The function of this processing is not understood. We have mapped the self-cleavage sites and have constructed parasites with cleavage site mutations. Surprisingly, a quadruple mutant that remains full-length retains in vitro activity, is trafficked normally, and supports normal egress, invasion and parasite growth. The N-terminal half of the prodomain stays bound to the catalytic domain even after processing and is required for proper intracellular trafficking of PM X. We find that this enzyme cleaves microneme and exoneme substrates before discharge, while the rhoptry substrates that are dependent on PM X activity are cleaved after exoneme discharge into the PV. The data give insight into the temporal, spatial and biochemical control of this unusual but important aspartic protease.

Climate dictates microbial community composition and diversity in Australian biological soil crusts (biocrusts).

The soil surface of drylands can typically be colonized by cyanobacteria and other microbes, forming biological soil crusts or 'biocrusts'. Biocrusts provide critical benefits to ecosystems and are a common component of the largely arid and semi-arid Australian continent. Yet, their distribution and the parameters that shape their microbial composition have not been investigated. We present here the first detailed description of Australia's biocrust microbiome assessed from 15 sites across the continent using 16S rRNA sequencing. The most abundant bacterial phyla from all sites were Cyanobacteria, Proteobacteria, Actinobacteria, Chloroflexi and Bacteroidetes. Cyanobacterial communities from northern regions were more diverse and unclassified cyanobacteria were a noticeable feature of northern biocrusts. Segregation between northern and southern regions was largely due to the differential abundance of Microcoleus spp., with M. paludosus dominating in the north and M. vaginatus dominating in the south. The geographical shifts in bacterial composition and diversity were correlated to seasonal temperatures and summer rainfall. Our findings provide an initial reference for sampling strategies to maximize access to bacterial genetic diversity. As hubs for essential ecosystem services, further investigation into biocrusts in arid and semi-arid regions may yield discoveries of genetic mechanisms that combat increases in warming due to climate change.

The Mutation Spectrum and Two Novel Point Mutations in the APC Gene in Vietnamese Patients with Familial Adenomatous Polyposis.

BACKGROUND: Familial adenomatous polyposis (FAP) is a hereditary disorder primarily caused by germline mutations in the APC gene. The most common type of mutation in the APC gene is point mutation, while deletion mutation is much less frequent. The current study was conducted to investigate the mutation spectrum of the APC gene in Vietnamese FAP patients. METHODS: Patients with the clinical diagnosis of FAP on colorectal endoscopy were screened for mutations in the APC gene using Sanger sequencing. Those who exhibited no point mutation subsequently underwent MLPA assay to detect deletion and duplication mutations. Besides, the relatives of patients with mutated APC genes were recruited for detecting carrier status. RESULTS: Sixty-three patients with clinical colorectal polyposis were recruited. Mutations in the APC gene were detected in 26/63 patients (41.3%). Genetic analysis of 105 asymptomatic relatives of these 26 patients found mutations in the APC gene in 55 individuals (52.4%). CONCLUSION: We successfully established the APC gene mutation spectrum in Vietnamese FAP patients for the first time. Of importance, we discovered two novel point mutations in the APC gene. The high prevalence of carrier status in asymptomatic family members of patients with mutation emphasizes the crucial role of appropriate genetic screening for early diagnosis, surveillance, and preventive measurements.

Asymmetric wall ingrowth deposition in Arabidopsis phloem parenchyma transfer cells is tightly associated with sieve elements.

In Arabidopsis, polarized deposition of wall ingrowths in phloem parenchyma (PP) transfer cells (TCs) occurs adjacent to cells of the sieve element/companion cell (SE/CC) complex. However, the spatial relationships between these different cell types in minor veins, where phloem loading occurs, are poorly understood. PP TC development and wall ingrowth localization were compared with those of other phloem cells in leaves of Col-0 and the transgenic lines AtSUC2::AtSTP9-GFP (green fluorescent protein) and AtSWEET11::AtSWEET11-GFP that identify CCs and PP cells, respectively. The development of PP TCs in minor veins, indicated by deposition of wall ingrowths, proceeded basipetally in leaves. However, not all PP cells develop wall ingrowths, and higher levels of deposition occur in abaxial- compared with adaxial-positioned PP TCs. Furthermore, the deposition of wall ingrowths was exclusively initiated on and preferentially covered the PP TC/SE interface, rather than the PP TC/CC interface, and only occurred in PP cells that were adjacent to SEs. Collectively, these results demonstrate a tight association between SEs and wall ingrowth deposition in PP TCs and suggest the existence of two subtypes of PP cells in leaf minor veins. Compared with PP cells, PP TCs showed more abundant accumulation of AtSWEET11-GFP, indicating functional differences in phloem loading between PP and PP TCs.

Bacterial community structure and metabolic potential in microbialite-forming mats from South Australian saline lakes.

Microbialites are sedimentary rocks created in association with benthic microorganisms. While they harbour complex microbial communities, Cyanobacteria perform critical roles in sediment stabilisation and accretion. Microbialites have been described from permanent and ephemeral saline lakes in South Australia; however, the microbial communities that generate and inhabit these biogeological structures have not been studied in detail. To address this knowledge gap, we investigated the composition, diversity and metabolic potential of bacterial communities from different microbialite-forming mats and surrounding sediments in five South Australian saline coastal lakes using 16S rRNA gene sequencing and predictive metagenome analyses. While Proteobacteria and Bacteroidetes were the dominant phyla recovered from the mats and sediments, Cyanobacteria were significantly more abundant in the mat samples. Interestingly, at lower taxonomic levels, the mat communities were vastly different across the five lakes. Comparative analysis of putative mat and sediment metagenomes via PICRUSt2 revealed important metabolic pathways driving the process of carbonate precipitation, including cyanobacterial oxygenic photosynthesis, ureolysis and nitrogen fixation. These pathways were highly conserved across the five examined lakes, although they appeared to be performed by distinct groups of bacterial taxa found in each lake. Stress response, quorum sensing and circadian clock were other important pathways predicted by the in silico metagenome analysis. The enrichment of CRISPR/Cas and phage shock associated genes in these cyanobacteria-rich communities suggests that they may be under selective pressure from viral infection. Together, these results highlight that a very stable ecosystem function is maintained by distinctly different communities in microbialite-forming mats in the five South Australian lakes and reinforce the concept that 'who' is in the community is not as critical as their net metabolic capacity.

The Distribution of Dengue Virus Serotype in Quang Nam Province (Vietnam) during the Outbreak in 2018.

Objectives: Quang Nam province in the Centre of Vietnam has faced an outbreak of dengue hemorrhagic fever (DHF) in 2018. Although DHF is a recurrent disease in this area, no epidemiological and microbiological reports on dengue virus serotypes have been conducted mainly due to lack of facilities for such a kind of advanced surveillance. The aim of this study was to detect different dengue virus serotypes in patients' blood samples. Design and Methods: Suspected cases living in Quang Nam province (Vietnam) and presenting clinical and hematological signs of dengue hemorrhagic fever were included in the study. The screening was performed, and the results were compared by using two methodologies: RT real-time PCR (RT-rPCR) and the Dengue NS1 rapid test. Results: From December 2018 to February 2019, looking both at RT-rPCR [+] and NS1 [+] methodologies, a total of 488 patients were screened and 336 were positive for dengue virus detection (74 children and 262 adults); 273 of these patients (81.3%) underwent viral serotype identification as follows: 12.82% (35/273) D1 serotype, 17.95% (49/273) D2, 0.37% (1/273) D3, 68.50 (187/283) D4, and 0.37% (1/273) D2+D4 serotypes. The RT-rPCR outcomes showed higher sensitivity during the first three days of infection compared to NS1 (92.3% vs. 89.7%). The NS1 increased sensitivity after the first 3 days whilst the RT-rPCR decreased. Conclusions: Advanced surveillance with dengue virus serotypes identification, if performed routinely, may help to predict and prevent further DHF epidemics based on the exposure of the different serotypes during different periods that lead to the intensification of disease severity as a consequence of antibody-dependent enhancement (ADE).

Photochemical and Electrochemical Applications of Proton-Coupled Electron Transfer in Organic Synthesis.

We present here a review of the photochemical and electrochemical applications of multi-site proton-coupled electron transfer (MS-PCET) in organic synthesis. MS-PCETs are redox mechanisms in which both an electron and a proton are exchanged together, often in a concerted elementary step. As such, MS-PCET can function as a non-classical mechanism for homolytic bond activation, providing opportunities to generate synthetically useful free radical intermediates directly from a wide variety of common organic functional groups. We present an introduction to MS-PCET and a practitioner's guide to reaction design, with an emphasis on the unique energetic and selectivity features that are characteristic of this reaction class. We then present chapters on oxidative N-H, O-H, S-H, and C-H bond homolysis methods, for the generation of the corresponding neutral radical species. Then, chapters for reductive PCET activations involving carbonyl, imine, other X═Y π-systems, and heteroarenes, where neutral ketyl, α-amino, and heteroarene-derived radicals can be generated. Finally, we present chapters on the applications of MS-PCET in asymmetric catalysis and in materials and device applications. Within each chapter, we subdivide by the functional group undergoing homolysis, and thereafter by the type of transformation being promoted. Methods published prior to the end of December 2020 are presented.

Depolymerization of Hydroxylated Polymers via Light-Driven C-C Bond Cleavage.

The accumulation of persistent plastic waste in the environment is widely recognized as an ecological crisis. New chemical technologies are necessary both to recycle existing plastic waste streams into high-value chemical feedstocks and to develop next-generation materials that are degradable by design. Here, we report a catalytic methodology for the depolymerization of a commercial phenoxy resin and high molecular weight hydroxylated polyolefin derivatives upon visible light irradiation near ambient temperature. Proton-coupled electron transfer (PCET) activation of hydroxyl groups periodically spaced along the polymer backbone furnishes reactive alkoxy radicals that promote chain fragmentation through C-C bond ß-scission. The depolymerization produces well-defined and isolable product mixtures that are readily diversified to polycondensation monomers. In addition to controlling depolymerization, the hydroxyl group modulates the thermomechanical properties of these polyolefin derivatives, yielding materials with diverse properties. These results demonstrate a new approach to polymer recycling based on light-driven C-C bond cleavage that has the potential to establish new links within a circular polymer economy and influence the development of new degradable-by-design polyolefin materials.

Perspectives from the Society for Pediatric Research: advice on sustaining science and mentoring during COVID-19.

The COVID-19 pandemic will leave an indelible mark on the careers of current medical trainees. Given the disruptions to medical education, economic impact on institutions, and the uncertainties around future job prospects, trainees are facing unprecedented challenges. This situation is especially concerning for futures of pediatric physician-scientist trainees, where concerns regarding maintaining the pipeline were well documented prior to the emergence of COVID-19. In this Perspectives article, we leverage the unique expertise of our workgroup to address concerns of physician-scientist trainees and to provide suggestions on how to navigate career trajectories in the post-COVID-19 era. We identified and addressed four major areas of concern: lack of in-person conferences and the associated decrease access to mentors and networking activities, decreased academic productivity, diminished job prospects, and mental health challenges. We also suggest actions for trainees, mentors and educational leaders, and institutions to help support trainees during the pandemic, with a goal of maintaining the pediatric physician-scientist pipeline.