Impacts assessment of nitrification inhibitors on U.S. agricultural emissions of reactive nitrogen gases.

Fertilizer-intensive agriculture leads to emissions of reactive nitrogen (Nr), posing threats to climate via nitrous oxide (N2O) and to air quality and human health via nitric oxide (NO) and ammonia (NH3) that form ozone and particulate matter (PM) downwind. Adding nitrification inhibitors (NIs) to fertilizers can mitigate N2O and NO emissions but may stimulate NH3 emissions. Quantifying the net effects of these trade-offs requires spatially resolving changes in emissions and associated impacts. We introduce an assessment framework to quantify such trade-off effects. It deploys an agroecosystem model with enhanced capabilities to predict emissions of Nr with or without the use of NIs, and a social cost of greenhouse gas to monetize the impacts of N2O on climate. The framework also incorporates reduced-complexity air quality and health models to monetize associated impacts of NO and NH3 emissions on human health downwind via ozone and PM. Evaluation of our model against available field measurements showed that it captured the direction of emission changes but underestimated reductions in N2O and overestimated increases in NH3 emissions. The model estimated that, averaged over applicable U.S. agricultural soils, NIs could reduce N2O and NO emissions by an average of 11% and 16%, respectively, while stimulating NH3 emissions by 87%. Impacts are largest in regions with moderate soil temperatures and occur mostly within two to three months of N fertilizer and NI application. An alternative estimate of NI-induced emission changes was obtained by multiplying the baseline emissions from the agroecosystem model by the reported relative changes in Nr emissions suggested from a global meta-analysis: -44% for N2O, -24% for NO and +20% for NH3. Monetized assessments indicate that on an annual scale, NI-induced harms from increased NH3 emissions outweigh (8.5-33.8 times) the benefits of reducing NO and N2O emissions in all agricultural regions, according to model-based estimates. Even under meta-analysis-based estimates, NI-induced damages exceed benefits by a factor of 1.1-4. Our study highlights the importance of considering multiple pollutants when assessing NIs, and underscores the need to mitigate NH3 emissions. Further field studies are needed to evaluate the robustness of multi-pollutant assessments.

Nucleoporin 93 Regulates Cancer Cell Growth and Stemness in Bladder Cancer via Wnt/ß-Catenin Signaling.

Bladder cancer (BLCA) is a prevalent cancer type with an unmet need for new therapeutic strategies. Nucleoporin 93 (Nup93) is implicated in the pathophysiology of several cancers, but its relationship with bladder cancer remains unclear. Nup93 expression was analyzed in TCGA datasets and 88 BLCA patient samples. Survival analysis and Cox regression models evaluated the association between Nup93 levels and patient prognosis. BLCA cells were used to investigate the effects of Nup93 overexpression or knockdown on cell growth, invasion, stemness (sphere formation and ALDH2 + cancer stem cell marker), and Wnt/ß-catenin signaling in vitro. The Wnt activator BML-284 was used to confirm the involvement of Wnt/ß-catenin signaling pathway. A xenograft mouse model validated the in vitro findings. Nup93 was highly expressed in BLCA tissues and cell lines, and high Nup93 expression correlated with poor prognosis in BLCA patients. Nup93 silencing inhibited BLCA cell proliferation, Wnt/ß-catenin activation, and cancer cell stemness. Conversely, Nup93 overexpression promoted these effects. BML-284 partially rescued the reduction in cell growth and stemness markers caused by Nup93 knockdown. Nup93 knockdown also suppressed the tumor formation of BLCA cells in vivo. Nup93 regulates BLCA cell growth and stemness via the Wnt/ß-catenin pathway, suggesting its potential as a prognostic marker and therapeutic target in BLCA.

Single-double-band switchable optical circular polarizers based on surface plasmon resonance: publisher's note.

This publisher's note reports a correction in Appl. Opt.63, 1153 (2024)APOPAI0003-693510.1364/AO.513837.

Single-double-band switchable optical circular polarizers based on surface plasmon resonance.

A single-double-band switchable circular polarization filter based on surface plasmon resonance exhibits significant potential for applications in fields such as communication and sensing due to its adjustable, low-cost, and easy integration features. In this study, we propose a bi-layer rod nanostructure and use FEM simulation to study the transmission spectra of the structure. The results demonstrate that the structure exhibits both single- and double-band circular polarization filtering effects, which can be switched by varying geometric parameters such as the distance between the two layers and the width of nanorods. Furthermore, the filtering effects of both single- and double-band are highly dependent on the length of the nanorods, with average extinction rates reaching 486 and 2020/129, respectively; the operating bandwidths (defined as extinction ratio >10) can reach 170 nm and 35 nm/70 nm, respectively. The underlying physical mechanisms are clarified by analyzing the electric dipole, magnetic dipole resonance modes, and induced chiral fields on nanostructures.

Matrix analysis method for evaluation of lens parameters influence in polarization transmission.

Most studies on the influence of lens parameters in polarization transmission have been carried out in the traditional geometric analysis method, which has the problems of low accuracy and complicated calculation. In this paper, taking the Galileo beam expanding system as an example, a matrix analysis method is proposed to characterize the process of polarization transmission, and derived the polarization azimuth deflection equation. The numerical simulations of the matrix analysis method and the geometric analysis method are compared with the Zemax simulations and the experiments. The variance of the matrix analysis method is compared with the geometric analysis method under four parameters of the lens. It turns out that the numerical simulation results of the two methods are consistent with the Zemax simulation and the experiments. The variance of the matrix analysis method is mostly smaller than that of the geometric analysis method, which further shows that the matrix analysis method is closer to the Zemax simulations and the experiments, and the accuracy is higher.

The Comparison of Machine Learning and Mechanistic In Vitro-In Vivo Extrapolation Models for the Prediction of Human Intrinsic Clearance.

Accurate prediction of human pharmacokinetics (PK) remains one of the key objectives of drug metabolism and PK (DMPK) scientists in drug discovery projects. This is typically performed by using in vitro-in vivo extrapolation (IVIVE) based on mechanistic PK models. In recent years, machine learning (ML), with its ability to harness patterns from previous outcomes to predict future events, has gained increased popularity in application to absorption, distribution, metabolism, and excretion (ADME) sciences. This study compares the performance of various ML and mechanistic models for the prediction of human IV clearance for a large (645) set of diverse compounds with literature human IV PK data, as well as measured relevant in vitro end points. ML models were built using multiple approaches for the descriptors: (1) calculated physical properties and structural descriptors based on chemical structure alone (classical QSAR/QSPR); (2) in vitro measured inputs only with no structure-based descriptors (ML IVIVE); and (3) in silico ML IVIVE using in silico model predictions for the in vitro inputs. For the mechanistic models, well-stirred and parallel-tube liver models were considered with and without the use of empirical scaling factors and with and without renal clearance. The best ML model for the prediction of in vivo human intrinsic clearance (CLint) was an in vitro ML IVIVE model using only six in vitro inputs with an average absolute fold error (AAFE) of 2.5. The best mechanistic model used the parallel-tube liver model, with empirical scaling factors resulting in an AAFE of 2.8. The corresponding mechanistic model with full in silico inputs achieved an AAFE of 3.3. These relative performances of the models were confirmed with the prediction of 16 Pfizer drug candidates that were not part of the original data set. Results show that ML IVIVE models are comparable to or superior to their best mechanistic counterparts. We also show that ML IVIVE models can be used to derive insights into factors for the improvement of mechanistic PK prediction.

Small molecule branched-chain ketoacid dehydrogenase kinase (BDK) inhibitors with opposing effects on BDK protein levels.

Branched chain amino acid (BCAA) catabolic impairments have been implicated in several diseases. Branched chain ketoacid dehydrogenase (BCKDH) controls the rate limiting step in BCAA degradation, the activity of which is inhibited by BCKDH kinase (BDK)-mediated phosphorylation. Screening efforts to discover BDK inhibitors led to identification of thiophene PF-07208254, which improved cardiometabolic endpoints in mice. Structure-activity relationship studies led to identification of a thiazole series of BDK inhibitors; however, these inhibitors did not improve metabolism in mice upon chronic administration. While the thiophenes demonstrated sustained branched chain ketoacid (BCKA) lowering and reduced BDK protein levels, the thiazoles increased BCKAs and BDK protein levels. Thiazoles increased BDK proximity to BCKDH-E2, whereas thiophenes reduced BDK proximity to BCKDH-E2, which may promote BDK degradation. Thus, we describe two BDK inhibitor series that possess differing attributes regarding BDK degradation or stabilization and provide a mechanistic understanding of the desirable features of an effective BDK inhibitor.

Research on the development and testing methods of physical education and agility training equipment in universities.

Introduction: Because of the problems of insufficient funds and traditional training methods in college sports agile training, an agile training system based on a wireless ad hoc network was developed to evaluate the effect of improving the sensitive quality of ordinary college students. Based on the ESP-MESH network, the lower computer realizes automatic networking between devices and tests the performance of the mesh network. Fourteen male college students received 9 weeks of agility training, with seven students in each of two groups: traditional agility training and agile equipment training. The researchers evaluated the performance of both groups in rapid disguise, body coordination, changing movements, and predictive decision-making. Results: There was no significant difference between the groups before training, but there were significant differences in the four abilities after training (p < 0.01). The experimental group had significant differences in rapid direction change and physical coordination (p < 0.05), and in changing movement and predictive decision-making ability (p < 0.01). Conclusion: Both traditional training and agile equipment training improve the agility quality of college students, and the latter shows better results in certain abilities. However, limited by other physical qualities, the improvement of motor changes and predictive decision-making ability is not as obvious as the other two abilities.

Characteristics of corticomuscular coupling during wheelchair Tai Chi in patients with spinal cord injury.

BACKGROUND: Wheelchair Tai Chi (WCTC) has been proved to have benefits for the brain and motor system of spinal cord injury (SCI) patients. However, the characteristics of corticomuscular coupling during WCTC are scarcely known. We aimed to investigate changes following SCI on corticomuscular coupling, and further compare the coupling characteristics of WCTC with aerobic exercise in SCI patients. METHODS: A total of 15 SCI patients and 25 healthy controls were recruited. The patients had to perform aerobic exercise and WCTC, while healthy controls needed to complete a set of WCTC. The participants accomplished the test following the tutorial video in a sitting position. The upper limb muscle activation was measured from upper trapezius, medial deltoid, biceps brachii and triceps brachii with surface electromyography. Cortical activity in the prefrontal cortex, premotor cortex, supplementary motor area and primary motor cortex was simultaneously collected by functional near-infrared spectroscopy. The functional connectivity, phase synchronization index and coherence values were then calculated and statistically analyzed. RESULTS: Compared to healthy controls, changes in functional connectivity and higher muscle activation were observed in the SCI group. There was no significant difference in phase synchronization between groups. Among patients, significantly higher coherence values between the left biceps brachii as well as the right triceps brachii and contralateral regions of interest were found during WCTC than during aerobic exercise. CONCLUSION: The patients may compensate for the lack of corticomuscular coupling by enhancing muscle activation. This study demonstrated the potential and advantages of WCTC in eliciting corticomuscular coupling, which may optimize rehabilitation following SCI.

Catalytic performance of Ni-Co/HZSM-5 catalysts for aromatic compound promotion in simulated bio-oil upgrading.

Bio-oil can be used as a substitute for fossil fuels after it is upgraded. Bimetal-modified HZSM-5 catalysts with various Ni-to-Co ratios were prepared to address catalysis problems, including deactivation of the catalysts and low hydrocarbon yields. The catalytic performance of Ni-Co/HZSM-5 in upgrading the simulated bio-oil was investigated with a fixed-bed reactor, and the influence of the loaded duplex metal ratio was also discussed. The new moderately strong/strong acid sites of Ni-Co/HZSM-5 changed according to the Ni/Co loading ratios, which substantially affected the acidity, catalytic activity and selectivity of the Ni-Co/HZSM-5. However, incorporating Co and Ni into the zeolite did not alter the structure of the HZSM-5. The interactions of the loaded bimetallic oxides reached equilibrium in 6Ni-4Co/HZSM-5, in which moderately strong acid sites and strong acid sites were formed after loading with Co3O4 and NiO. With a suitable acid site ratio, 6Ni-4Co/HZSM-5 exhibited excellent performance, with a lower coke deposition of 3.29 wt% and stable catalytic activity, and the conversion remained at 83-73% during 360 min of uninterrupted catalysis. Periodic changes in the acid sites and interfacial protons were the critical factors that improved the properties of the 6Ni-4Co/HZSM-5 and enhanced its selectivity for aromatic compounds.

Evaluation of the Impact of Ritlecitinib on Organic Cation Transporters Using Sumatriptan and Biomarkers as Probes.

Ritlecitinib, an inhibitor of Janus kinase 3 and hepatocellular carcinoma family kinases, is in development as potential treatment for several inflammatory diseases. In vitro studies presented ritlecitinib as an inhibitor of hepatic organic cation transporter (OCT) 1, renal transporters OCT2 and multidrug and toxin extrusion (MATE) proteins 1/2K using multiple substrates, and ritlecitinib's major inactive metabolite M2, as an inhibitor of OCT1. A clinical interaction study with an OCT1 drug probe (sumatriptan) and relevant probe biomarkers for OCT/MATE was conducted to assess the effect of ritlecitinib on these transporters in healthy adult participants. The selectivity of sumatriptan for OCT1 was confirmed through a series of in vitro uptake assays. A simple static model was used to help contextualize the observed changes in sumatriptan area under the plasma concentration-time curve (AUC). Coadministration of a single 400-mg dose of ritlecitinib increased sumatriptan AUC from time 0 to infinity (AUCinf ) by ≈30% relative to a single 25-mg sumatriptan administration alone. When administered 8 hours after a ritlecitinib dose, sumatriptan AUCinf increased by ≈50% relative to sumatriptan given alone. Consistent with OCT1 inhibition, the AUC from time 0 to 24 hours of isobutyryl-L-carnitine decreased by ≈15% after ritlecitinib. Based on the evaluation of the renal clearance of N1 -methylnicotinamide, ritlecitinib does not exert clinically meaningful inhibition on renal OCT2 or MATE1/2K. This study confirmed that ritlecitinib and M2 are inhibitors of OCT1 but not OCT2 or MATE1/2K in healthy adults.

Enhancement effect of biochar addition on anaerobic co-digestion of pig manure and corn straw under biogas slurry circulation.

Based on the semi-continuous anaerobic co-digestion (AcoD) reactor, the effects of biochar addition on the internal environmental changes and gas production characteristics were studied under the condition of biogas slurry recirculation. The results showed that the addition of biochar enhanced the degradation and metabolic pathways of acetate and propionate, thereby reducing the concentrations of volatile fatty acids (VFAs), total ammonia and chemical oxygen demand by 55 %, 41 % and 61 %, respectively. The buffer system formed by the combination of NH4+ and VFAs of C2-C5 was also enhanced, thereby improving the stability of the system. The addition of biochar effectively increased the relative abundance of Bacteroidetes, Chloroflexi, Spirochaetota and Synergistota, and enhanced three methanogenic metabolic pathways. This study provides scientific support for the application of biochar to solve the system inhibition in mixed substrate semi-continuous AcoD process and provides technical support for the stable operation of biogas project.

Requirement for PINCH in skeletal myoblast differentiation.

PINCH, an adaptor of focal adhesion complex, plays essential roles in multiple cellular processes and organogenesis. Here, we ablated PINCH1 or both of PINCH1 and PINCH2 in skeletal muscle progenitors using MyoD-Cre. Double ablation of PINCH1 and PINCH2 resulted in early postnatal lethality with reduced size of skeletal muscles and detachment of diaphragm muscles from the body wall. PINCH mutant myofibers failed to undergo multinucleation and exhibited disrupted sarcomere structures. The mutant myoblasts in culture were able to adhere to newly formed myotubes but impeded in cell fusion and subsequent sarcomere genesis and cytoskeleton organization. Consistent with this, expression of integrin ß1 and some cytoskeleton proteins and phosphorylation of ERK and AKT were significantly reduced in PINCH mutants. However, N-cadherin was correctly expressed at cell adhesion sites in PINCH mutant cells, suggesting that PINCH may play a direct role in myoblast fusion. Expression of MRF4, the most highly expressed myogenic factor at late stages of myogenesis, was abolished in PINCH mutants that could contribute to observed phenotypes. In addition, mice with PINCH1 being ablated in myogenic progenitors exhibited only mild centronuclear myopathic changes, suggesting a compensatory role of PINCH2 in myogenic differentiation. Our results revealed a critical role of PINCH proteins in myogenic differentiation.

Soil Nitrogen Content Detection Based on Near-Infrared Spectroscopy.

Traditional soil nitrogen detection methods have the characteristics of being time-consuming and having an environmental pollution effect. We urgently need a rapid, easy-to-operate, and non-polluting soil nitrogen detection technology. In order to quickly measure the nitrogen content in soil, a new method for detecting the nitrogen content in soil is presented by using a near-infrared spectrum technique and random forest regression (RF). Firstly, the experiment took the soil by the Xunsi River in the area of Hubei University of Technology as the research object, and a total of 143 soil samples were collected. Secondly, NIR spectral data from 143 soil samples were acquired, and chemical and physical methods were used to determine the content of nitrogen in the soil. Thirdly, the raw spectral data of soil samples were denoised by preprocessing. Finally, a forecast model for the soil nitrogen content was developed by using the measured values of components and modeling algorithms. The model was optimized by adjusting the changes in the model parameters and Gini coefficient (∆Gini), and the model was compared with the back propagation (BP) and support vector machine (SVM) models. The results show that: the RF model modeling set prediction R2C is 0.921, the RMSEC is 0.115, the test set R2P is 0.83, and the RMSEP is 0.141; the detection of the soil nitrogen content can be realized by using a near-infrared spectrum technique and random forest algorithm, and its prediction accuracy is better than that of the BP and SVM models; using ∆ Gini to optimize the RF modeling data, the spectral information of the soil nitrogen content can be extracted, and the data redundancy can be reduced effectively.

Effects of long-term COVID-19 confinement and music stimulation on mental state and brain activity of young people.

The Corona Virus Disease 2019 (COVID-19) pandemic may have had a negative emotional impact on individuals. This study investigated the effect of long-term lockdown and music on young people's mood and neurophysiological responses in the prefrontal cortex (PFC). Fifteen healthy young adults were recruited and PFC activation was acquired using functional near-infrared spectroscopy during the conditions of resting, Stroop and music stimulation. The Depression Anxiety Stress Scales mental scale scores were simultaneously recorded. Mixed effect models, paired t-tests, one-way ANOVAs and Spearman analyses were adopted to analyse the experimental parameters. Stress, anxiety and depression levels increased significantly from Day 30 to Day 40. In terms of reaction time, both Stroop1 and Stroop2 were faster on Day 40 than on Day 30 (P = 0.01, P = 0.003). The relative concentration changes of oxyhemoglobin were significantly higher during premusic conditions than music stimulation and postmusic Stroop. The intensity of functional connectivity shifted from inter- to intracerebral over time. In conclusion, the reduced hemodynamic response of the PFC in healthy young adults is associated with negative emotions, especially anxiety, during lockdown. Immediate music stimulation appears to improve efficiency by altering the pattern of connections in PFC.

The Transverse Bearing Characteristics of the Pile Foundation in a Calcareous Sand Area.

Reviewing literature revealed that the studies on the bearing characteristics of pile foundations mainly focuses on clay, ordinary sand, loess, saline soil, and other areas. However, few studies on the bearing characteristics of the pile foundation in calcareous sand were conducted. Besides, existing traditional studies ignored the variation of soil compression modulus with depth, and the effect of void ratio on the transverse bearing characteristics of the pile foundation in a calcareous sand area were not well understood. In response of these problems, this study conducted a theoretical investigation on the transverse bearing characteristics of the pile foundation in a calcareous sand area. The transverse bearing characteristics of the pile foundation were derived based on the Pasternak foundation model and the Winkler foundation model, incorporating the heterogeneous distribution of compressive modulus with buried depth. The calculation results of the Pasternak foundation model are closer to the observed results than the Winkler foundation model. Therefore, the following research on the transverse bearing characteristics of the pile foundation in the calcareous sand area adopts the Pasternak foundation model. Then, the effects of the pile length, pile diameter, pile elastic modulus, horizontal load, bending moment, and void ratio on the transverse bearing characteristics of the pile foundation in a calcareous sand area were thoroughly analyzed. Furthermore, the difference between the transverse bearing characteristics of the pile foundation in a calcareous sand area and a quartz sand area was discussed. Results show that the horizontal displacement of the pile top in a calcareous sand area is greater than the quartz sand area under the same conditions.

Development and implementation of urinary transporter biomarkers to facilitate assessment of drug-drug interaction.

Aim: Novel urinary biomarker evaluation approaches to support inhibition assessment for renal transporters (e.g., OCT2, multidrug and toxin extrusion proteins [MATEs]). Methods: Highly sensitive and robust hydrophilic interaction chromatography-MS/high-resolution MS assays, for urine and plasma, were developed and characterized to evaluate transporter biomarkers including N1-methyladenosine and N1-methylnicotinamide. Results: The assays were simple and reliable with good selectivity and sensitivity, and successfully supported a clinical drug-drug interaction study with a drug candidate that presented in vitro inhibition of OCT2 and MATEs. Conclusion: The multiplexed assays enable a performance comparison, including biomarker specificity and sensitivity, that should increase the confidence in early clinical OCT2/MATEs drug-drug interaction risk assessment.

Salvianolic acid B attenuates membranous nephropathy by activating renal autophagy via microRNA-145-5p/phosphatidylinositol 3-kinase/AKT pathway.

The abnormal proliferation and inflammatory response of the mesangial cells play a crucial role in the progression of membranous nephropathy (MN). Herein, this study aimed to investigate the therapeutic effect of Salvianolic acid B (SalB) on MN-induced mesangial abnormalities and its underlying mechanisms. MN models were established in cationic bovine serum albumin-induced Sprague-Dawley rats and lipopolysaccharide-induced human mesangial cells (HMCs). Following SalB and microRNA-145-5p antagomir treatment, kidney function was investigated by 24-hours urine protein, serum creatinine, and blood urea nitrogen. Pathological changes of kidney were investigated by Periodic acid Schiff staining. CD68 and IgG were detected by immunofluorescence in glomerulus. Mesangial autophagosomes were observed by transmission electron microscope. MicroRNA-145-5p inhibitor, mimic, LY294002, and SalB were used to treat with HMCs. In kidney and HMCs, IL-1 ß, IL-2, IL-6, TNF-α and microRNA-145-5p was detected by quantitative real-time PCR. Phosphatidylinositol 3-kinase (PI3K), phosphorylated AKT, AKT, beclin1, and microtubule-associated protein light chain 3 (LC3) levels were detected by Western blot. HMCs proliferation and cycle were detected by Cell Counting Kit-8 and flow cytometry. LC3 were detected by LC3-dual-fluorescent adenovirus in HMCs. Our results showed that SalB significantly ameliorated kidney function and pathological changes. Furthermore, it significantly alleviated proliferation, inflammation and activated autophagy in mesangial cells. Moreover, microRNA-145-5p antagomir accentuated MN while microRNA-145-5p inhibitor and LY294002 encouraged proliferation and inflammation through PI3K/AKT pathway in HMCs. Collectively, our study demonstrated that SalB activated renal autophagy to reduce cell proliferation and inflammation of MN, which was mediated by microRNA-145-5p to inhibit PI3K/AKT pathway, and ultimately attenuated MN.

Integrated Modeling of U.S. Agricultural Soil Emissions of Reactive Nitrogen and Associated Impacts on Air Pollution, Health, and Climate.

Agricultural soils are leading sources of reactive nitrogen (Nr) species including nitrogen oxides (NOx), ammonia (NH3), and nitrous oxide (N2O). The propensity of NOx and NH3 to generate ozone and fine particulate matter and associated impacts on health are highly variable, whereas the climate impacts of long-lived N2O are independent of emission timing and location. However, these impacts have rarely been compared on a spatially resolved monetized basis. In this study, we update the nitrogen scheme in an agroecosystem model to simulate the Nr emissions from fertilized soils across the contiguous United States. We then apply a reduced-form air pollution health effect model to assess air quality impacts from NOx and NH3 and a social cost of N2O to assess the climate impacts. Assuming an $8.2 million value of a statistical life and a $13,100/ton social cost of N2O, the air quality impacts are a factor of ∼7 to 15 times as large as the climate impacts in heavily populated coastal regions, whereas the ratios are closer to 2.5 in sparsely populated regions. Our results show that air pollution, health, and climate should be considered jointly in future assessments of how farming practices affect Nr emissions.

2021 White Paper on Recent Issues in Bioanalysis: Mass Spec of Proteins, Extracellular Vesicles, CRISPR, Chiral Assays, Oligos; Nanomedicines Bioanalysis; ICH M10 Section 7.1; Non-Liquid & Rare Matrices; Regulatory Inputs (Part 1A - Recommendations on Endogenous Compounds, Small Molecules, Complex Methods, Regulated Mass Spec of Large Molecules, Small Molecule, PoC & Part 1B - Regulatory Agencies' Inputs on Bioanalysis, Biomarkers, Immunogenicity, Gene & Cell Therapy and Vaccine).

The 15th edition of the Workshop on Recent Issues in Bioanalysis (15th WRIB) was held on 27 September to 1 October 2021. Even with a last-minute move from in-person to virtual, an overwhelmingly high number of nearly 900 professionals representing pharma and biotech companies, contract research organizations (CROs), and multiple regulatory agencies still eagerly convened to actively discuss the most current topics of interest in bioanalysis. The 15th WRIB included 3 Main Workshops and 7 Specialized Workshops that together spanned 1 week in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy, cell therapy and vaccines. Moreover, in-depth workshops on biomarker assay development and validation (BAV) (focused on clarifying the confusion created by the increased use of the term "Context of Use - COU"); mass spectrometry of proteins (therapeutic, biomarker and transgene); state-of-the-art cytometry innovation and validation; and, critical reagent and positive control generation were the special features of the 15th edition. This 2021 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop, and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2021 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 1A) covers the recommendations on Endogenous Compounds, Small Molecules, Complex Methods, Regulated Mass Spec of Large Molecules, Small Molecule, PoC. Part 1B covers the Regulatory Agencies' Inputs on Bioanalysis, Biomarkers, Immunogenicity, Gene & Cell Therapy and Vaccine. Part 2 (ISR for Biomarkers, Liquid Biopsies, Spectral Cytometry, Inhalation/Oral & Multispecific Biotherapeutics, Accuracy/LLOQ for Flow Cytometry) and Part 3 (TAb/NAb, Viral Vector CDx, Shedding Assays; CRISPR/Cas9 & CAR-T Immunogenicity; PCR & Vaccine Assay Performance; ADA Assay Comparabil ity & Cut Point Appropriateness) are published in volume 14 of Bioanalysis, issues 10 and 11 (2022), respectively.