Synthesis, Spectral Characterization and Photoluminescence of 3-chloro-6-methoxy-2-(methylsulfanyl)quinoxaline in Different Solvents: An Experimental and Theoretical Investigation Using DFT.

In the present work, we synthesized 3-chloro-6-methoxy-2-(methyl sulfanyl) quinoxaline (3MSQ) using a microwave-assisted synthesis method. The physicochemical structural analysis of the synthesized compound utilizing 1H-NMR, 13C-NMR, and FT-IR spectroscopy techniques. The photophysical properties of 3MSQ was examined through absorption and fluorescence spectroscopy. Spectroscopic analyses revealed a bathochromic shift in both absorption and fluorescence spectra, attributed to the π → π* transition. Ground and excited state dipole moments was experimentally determined using the solvatochromic shift method, employing various correlations such as Lippert's, Bakhshiev's, Kawski-Chamma-Viallet's equations, and solvent polarity parameters. Our findings indicate that the excited state dipole moments exceed those of the ground state, suggesting increased polarity in the excited state. Further, the while detailed bond length, bond angles, dihedral angles, Mulliken charge distribution, ground state dipole moments and HOMO-LUMO energy gap estimated through ab initio computations using Gaussian-09W. The value of energy band gap obtained from both the methods are in good agreement. Furthermore, employing DFT computational analysis, we identified reactive centers such as electrophilic and nucleophilic sites using molecular electrostatic potential (MESP) 3D plots. Additionally, CIE chromaticity analysis was performed to understand the photoluminescent properties of 3MSQ. The insights derived from these analyses contribute to a better understanding of the molecule's electronic structure, photophysical properties, and solute-solvent interactions, thus providing valuable information regarding its behaviour and characteristics under diverse conditions. These results contribute to a comprehensive understanding of the molecular structure and properties of 3-chloro-6-methoxy-2-(methyl sulfanyl) quinoxaline (3MSQ).

Clinical trial recommendations using Semantics-Based inductive inference and knowledge graph embeddings.

OBJECTIVE: Designing a new clinical trial entails many decisions, such as defining a cohort and setting the study objectives to name a few, and therefore can benefit from recommendations based on exhaustive mining of past clinical trial records. This study proposes an approach based on knowledge graph embeddings and semantics-driven inductive inference for generating such recommendations. METHOD: The proposed recommendation methodology is based on neural embeddings trained on first-of-its-kind knowledge graph constructed from clinical trials data. The methodology includes design of a knowledge graph for clinical trial data, evaluation of various knowledge graph embedding techniques for it, application of a novel inductive inference method using these embeddings, and generation of recommendations for clinical trial design. The study uses freely available data from clinicaltrials.gov and related sources. RESULTS: The proposed approach for recommendations obtained relevance scores ranging from 70% to 83%. These scores were determined by evaluating the text similarity of recommended elements to actual elements used in clinical trials that are in progress. Furthermore, the most pertinent recommendations were consistently located towards the top of the list, indicating the effectiveness of our method. CONCLUSION: Our study suggests that inductive inference using node semantics is a viable approach for generating recommendations using graphs neural embeddings, and that there is a potential for improvement in training graph embeddings using node semantics.

Synthesis of nano hydroxyapatite from Hypopthalmichthys molitrix (silver carp) bone waste by two different methods: a comparative biophysical and in vitro evaluation on osteoblast MG63 cell lines.

More than a thousand tonnes of fish bone wastes can be transformed into biomedical products annually. Alkaline hydrolysis and thermal calcification were used to create nanosized hydroxyapatite (HAp) crystals from Silver carp bone wastes. Biophysical tests were used to determine the nano size and chemical composition of synthesised hydroxyapatite. Alkaline hydrolysis hydroxyapatite (AH-HAp) was 58.3 nm, while Thermal calcination hydroxyapatite (TC-HAp) was 64.3 nm in size, confirmed by Atomic Force Microscopy. Energy Dispersive X-ray Analysis studies showed Ca/P (Calcium phosphate) ratio of AH-HAp to be 1.65, whereas TC-HAp as 1.45, confirming AH-HAp to be organically rich along with a similar Ca/P ratio as natural HAp. Fourier Transform Infrared Spectroscopy spectra indicated HAp formation from both procedures, however AH-HAp had superior crystallinity than TC-HAp confirmed from X-Ray Diffraction spectra. MG63 osteoblast cell lines showed 91% cell viability in cytotoxicity studies and 70.1% proliferation efficiency in Alkaline Phosphatase assay, which was higher than TC-HAp. The present study shows that HAp produced via alkaline hydrolysis has better biocompatibility which enhances its applicability as a biomaterial, than HAp synthesized through thermal calcination, which tends to incinerate organic moieties.

Using the contextual language model BERT for multi-criteria classification of scientific articles.

BACKGROUND: Finding specific scientific articles in a large collection is an important natural language processing challenge in the biomedical domain. Systematic reviews and interactive article search are the type of downstream applications that benefit from addressing this problem. The task often involves screening articles for a combination of selection criteria. While machine learning was previously used for this purpose, it is not known if different criteria should be modeled together or separately in an ensemble model. The performance impact of the modern contextual language models on the task is also not known. METHODS: We framed the problem as text classification and conducted experiments to compare ensemble architectures, where the selection criteria were mapped to the components of the ensemble. We proposed a novel cascade ensemble analogous to the step-wise screening process employed in developing the gold standard. We compared performance of the ensembles with a single integrated model, which we refer to as the individual task learner (ITL). We used SciBERT, a variant of BERT pre-trained on scientific articles, and conducted experiments using a manually annotated dataset of ~49 K MEDLINE abstracts, known as Clinical Hedges. RESULTS: The cascade ensemble had significantly higher precision (0.663 vs. 0.388 vs. 0.478 vs. 0.320) and F measure (0.753 vs. 0.553 vs. 0.628 vs. 0.477) than ITL and ensembles using Boolean logic and a feed-forward network. However, ITL had significantly higher recall than the other classifiers (0.965 vs. 0.872 vs. 0.917 vs. 0.944). In fixed high recall studies, ITL achieved 0.509 precision @ 0.970 recall and 0.381 precision @ 0.985 recall on a subset that was studied earlier, and 0.295 precision @ 0.985 recall on the full dataset, all of which were improvements over the previous studies. CONCLUSION: Pre-trained neural contextual language models (e.g. SciBERT) performed well for screening scientific articles. Performance at high fixed recall makes the single integrated model (ITL) more suitable among the architectures considered here, for systematic reviews. However, high F measure of the cascade ensemble makes it a better approach for interactive search applications. The effectiveness of the cascade ensemble architecture suggests broader applicability beyond this task and the dataset, and the approach is analogous to query optimization in Information Retrieval and query optimization in databases.

Effect of infraorbital nerve block on postoperative pain and 30-day morbidity at the donor site in buccal mucosal graft urethroplasty.

BACKGROUND AND AIMS: Buccal mucosa harvest for substitution urethroplasty can be painful, and may be associated with long-term complications such as perioral numbness, persistent difficulty with mouth opening, and change in salivary function. This study was designed to evaluate the efficacy of infraorbital nerve block (IOB) in relieving postoperative pain at the donor site of the buccal mucosal graft (BMG) and its associated morbidity at 30 days. MATERIAL AND METHODS: Thirty adults scheduled for BMG urethroplasty were enrolled in this study and were randomized to receive either no block group I (control) and IOB group II intraorally with 1 mL of 0.5% bupivacaine. Pain was assessed by visual analog scale, intraoral morbidity, and patient satisfaction in the immediate postoperative period. All patients were reviewed after 1 month for morbidity such as perioral numbness, pain on mastication, and tightness on mouth opening. Statistical analysis was done using Mann-Whitney's U and Chi-square tests. RESULTS: Median time to pain-free oral intake for liquids (group I: 2-5 days, group II: 1 day, P < 0.001) and solids (group I: 4 days, group II: 2 days, P < 0.001) was earlier in group II. At the follow-up after 1 month, one patient in group II and three patients in group I showed perioral numbness (P = 0.026), and five patients had pain on mastication in group I (P = 0.016). CONCLUSION: IOB is associated with postoperative analgesia and facilitation of early food intake, mitigating the morbidity of the donor site and provides satisfaction.

Clinical associations of proinflammatory cytokines, oxidative biomarkers and vitamin D levels in systemic lupus erythematosus.

Background The abnormal biological activity of cytokines plays an important role in the pathophysiology of both systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS). Several studies have highlighted the association of vitamin D and certain pro-inflammatory cytokines with disease activity in SLE. However, there are limited data on the association of vitamin D and antiphospholipid antibodies (aPL) with various proinflammatory biomarkers in these patients and their relative impact on clinical outcomes. Methods The serum levels of several aPL, 25-hydroxy-vitamin D, pro-inflammatory cytokines including IFNα, IL-1ß, IL-6, IL-8, IP10, sCD40L, TNFα and VEGF were measured in 312 SLE patients from the Jamaican ( n = 45) and Hopkins ( n = 267) lupus cohorts using commercial Milliplex and ELISA assays. Oxidized LDL/ß2glycoprotein antigenic complexes (oxLß2Ag) and their associated antibodies were also measured in the Jamaican cohort. Healthy controls for oxidative marker and cytokine testing were used. Results Abnormally low vitamin D levels were present in 61.4% and 73.3% of Hopkins and Jamaican SLE patients, respectively. Median concentrations of IP10, TNFα, sCD40L and VEGF were elevated in both cohorts, oxLß2Ag and IL-6 were elevated in the Jamaican cohort, and IFNα, IL-1ß and IL-8 were the same or lower in both cohorts compared to controls. IP10 and VEGF were independent predictors of disease activity, aPL, IP10 and IL-6 were independent predictors of thrombosis and IL-8, and low vitamin D were independent predictors of pregnancy morbidity despite there being no association of vitamin D with pro-inflammatory cytokines. Conclusions Our results indicate that aPL-mediated pro-inflammatory cytokine production is likely a major mechanism of thrombus development in SLE patients. We provide presumptive evidence of the role IL-8 and hypovitaminosis D play in obstetric pathology in SLE but further studies are required to characterize the subtle complexities of vitamin D's relationship with cytokine production and disease activity in these patients.

Cardiometabolic disease in South Asians: A global health concern in an expanding population.

Cardiovascular disease (CVD) is one of the main causes of mortality and morbidity worldwide. As an emerging population, South Asians (SAs) bear a disproportionately high burden of CVD relative to underlying classical risk factors, partly attributable to a greater prevalence of insulin resistance and diabetes and distinct genetic and epigenetic influences. While the phenotypic distinctions between SAs and other ethnicities in CVD risk are becoming increasingly clear, the biology of these conditions remains an area of active investigation, with emerging studies involving metabolism, genetic variation and epigenetic modifiers (e.g., extracellular RNA). In this review, we describe the current literature on prevalence, prognosis and CVD risk in SAs, and provide a landscape of translational research in this field toward ameliorating CVD risk in SAs.

Outcome of liver transplantation in patients with hereditary bleeding disorders: a single centre UK experience.

INTRODUCTION: Patients with hereditary bleeding disorders who have developed end-stage liver disease as a consequence of hepatitis C infection (HCV) acquired from factor concentrates prior to the introduction of viral inactivation continue to be referred for liver transplantation. METHODS: A retrospective review of case notes and electronic records was performed on all patients with bleeding disorders who have undergone liver transplantation at the University Hospital Birmingham (UHB). RESULTS: Between 1990 and 2014, 35 liver transplants have been performed in 33 patients with hereditary bleeding disorders. The indication for transplantation was mainly end-stage liver disease secondary to HCV. Five patients had human immunodeficiency virus (HIV) co-infection. No excess mortality due to bleeding occurred in the peri or postoperative period. Median overall survival post transplant is 9.7 years. Overall survival rates at 1, 3 and 5 years are 90%, 72% and 64% respectively. The predominant cause of mortality was liver failure secondary to either recurrent HCV or recurrent hepatocellular carcinoma (HCC). The median overall survival in patients with HIV co-infection is shorter than in those with mono-infection but this is not statistically significant. Patients with a pre-existing HCC had a statistically significant shorter survival (2.4 years vs. 13.6 years, P = 0.007). CONCLUSION: Liver transplantation has become an accepted treatment option for patients with hereditary bleeding disorders and HCV associated end-stage liver disease with survival rates similar to non-bleeding disorder patients.

The association of lean and fat mass with all-cause mortality in older adults: The Cardiovascular Health Study.

BACKGROUND AND AIMS: Understanding contributions of lean and fat tissue to cardiovascular and non-cardiovascular mortality may help clarify areas of prevention in older adults. We aimed to define distributions of lean and fat tissue in older adults and their contributions to cause-specific mortality. METHODS AND RESULTS: A total of 1335 participants of the Cardiovascular Health Study (CHS) who underwent dual-energy x-ray absorptiometry (DEXA) scans were included. We used principal components analysis (PCA) to define two independent sources of variation in DEXA-derived body composition, corresponding to principal components composed of lean ("lean PC") and fat ("fat PC") tissue. We used Cox proportional hazards regression using these PCs to investigate the relationship between body composition with cardiovascular and non-cardiovascular mortality. Mean age was 76.2 ± 4.8 years (56% women) with mean body mass index 27.1 ± 4.4 kg/m2. A greater lean PC was associated with lower all-cause (HR = 0.91, 95% CI 0.84-0.98, P = 0.01) and cardiovascular mortality (HR = 0.84, 95% CI 0.74-0.95, P = 0.005). The lowest quartile of the fat PC (least adiposity) was associated with a greater hazard of all-cause mortality (HR = 1.24, 95% CI 1.04-1.48, P = 0.02) relative to fat PCs between the 25th-75th percentile, but the highest quartile did not have a significantly greater hazard (P = 0.70). CONCLUSION: Greater lean tissue mass is associated with improved cardiovascular and overall mortality in the elderly. The lowest levels of fat tissue mass are linked with adverse prognosis, but the highest levels show no significant mortality protection. Prevention efforts in the elderly frail may be best targeted toward improvements in lean muscle mass.

Abdominal fat radiodensity, quantity and cardiometabolic risk: The Multi-Ethnic Study of Atherosclerosis.

BACKGROUND AND AIMS: Fat radiodensity, as measured by fat attenuation on computed tomography (CT), has emerged as a potential biomarker of "fat quality." We sought to characterize the relationship between fat radiodensity and quantity in subcutaneous, visceral, and intermuscular fat depots, and its role in inflammation, insulin resistance, and metabolic syndrome (MetS). METHODS AND RESULTS: We studied 1511 individuals from the Multi-Ethnic Study of Atherosclerosis who underwent CT for measurement of regional fat distribution and radiodensity, along with biomarker assessments and adjudication of incident metabolic syndrome (MetS). Linear, logistic and Cox regression analyses were used to measure association between fat radiodensity and (1) fat quantity, (2) biomarkers of cardiometabolic dysfunction, and (3) both prevalent and incident MetS. In each fat depot, radiodensity was strongly and inversely associated with quantity (e.g., visceral fat radiodensity vs. quantity: ρ = -0.82, P < 0.01). After adjustment for age, sex and race, lower visceral fat radiodensity was associated with greater C-reactive protein, leptin and insulin, but lower adiponectin (P < 0.01 for all). After full adjustment for cardiovascular disease risk factors, visceral (but not subcutaneous or intermuscular) fat radiodensity was associated with prevalent MetS (OR = 0.96, 95% CI = 0.93-0.99, P = 0.01). Moreover, lower visceral fat radiodensity was associated with incident MetS after the same adjustment (HR = 0.95, 95% CI 0.93-0.98, P < 0.01). However, this association became non-significant after further adjustment for visceral fat quantity. CONCLUSION: Fat radiodensity is strongly correlated with fat quantity and relevant inflammatory biomarkers. Fat radiodensity (especially for visceral fat) may be a complementary, easily assessed marker of cardiometabolic risk.

Diet and adipose tissue distributions: The Multi-Ethnic Study of Atherosclerosis.

BACKGROUND AND AIMS: Dietary quality affects cardiometabolic risk, yet its pathways of influence on regional adipose tissue depots involved in metabolic and diabetes risk are not well established. We aimed to investigate the relationship between dietary quality and regional adiposity. METHODS AND RESULTS: We investigated 5079 individuals in the Multi-Ethnic Study of Atherosclerosis (MESA) who had food-frequency questionnaires and measurement of pericardial fat and hepatic attenuation at the baseline study visit in MESA, as well as a subgroup with imaging for visceral and subcutaneous fat (N = 1390). A dietary quality score (DietQuality) was constructed to include established food group constituents of a Mediterranean-type diet. Linear models estimated associations of dietary score as well as its constituents with regional adiposity. Baseline mean age was 61 (± 10) years, and approximately half of the participants (47%) were male. Those with a higher DietQuality score were generally older, female, with a lower body mass index, C-reactive protein, and markers of insulin resistance. After adjustment, a higher DietQuality score was associated with lower visceral fat (lowest vs. highest dietary score quartile: 523.6 vs. 460.5 cm(2)/m; P < 0.01 for trend), pericardial fat (47.5 vs. 41.3 cm(3)/m; P < 0.01 for trend), lesser hepatic steatosis (by hepatic attenuation; 58.6 vs. 60.7 Hounsfield units; P < 0.01 for trend), but not subcutaneous fat (P = 0.39). Greater fruits, vegetables, whole grains, seeds/nuts and yogurt intake were associated with decreased adiposity, while red/processed meats were associated with greater regional adiposity. CONCLUSION: A higher quality diet pattern is associated with less regional adiposity, suggesting a potential mechanism of beneficial dietary effects on diabetes, metabolic, and cardiovascular risk.

Structural phase transformation and microwave dielectric studies of SmNb(1-x)(Si(1/2)Mo(1/2))(x)O(4) compounds with fergusonite structure.

Temperature- and composition-induced phase transition in SmNbO4 was studied by differential scanning calorimetry, Raman spectroscopy and high-temperature powder X-ray diffraction measurements. In situ X-ray diffraction studies revealed that SmNbO4 possesses a monoclinic fergusonite crystal structure at ambient temperature and transforms to a tetragonal scheelite structure above the transition temperature (To ≥ 800 °C). The second-order nature of this transition was confirmed by observing a linear relationship between the spontaneous strain (es) of SmNbO4 and the Landau order parameter (η) around the phase transition temperature. We stabilized this high-temperature tetragonal scheelite phase at ambient temperature by substituting Si(4+) and Mo(6+) into the Nb site of SmNbO4. The SmNb1-x(Si1/2Mo1/2)xO4 (x = 0.0-0.69) ceramic compositions were prepared by the conventional solid-state reaction method. Rietveld refinement was carried out on all the compositions to examine the phase purity, and the compositions where x < 0.06 all formed a monoclinic fergusonite structure (I2/a space group, Z = 2). Both the X-ray diffraction and Raman spectroscopy measurements revealed that increasing the concentration of x transformed the structure from monoclinic fergusonite to tetragonal scheelite (I41/a space group, Z = 4) at a critical concentration (xc). Both the monoclinic and tetragonal phases coexisted in the composition range of 0.06 ≤ x < xc. The Hakki-Coleman and reflection cavity techniques were used to measure the dielectric constant and quality factor of these stabilized phases, respectively. The temperature coefficient of the resonant frequency was measured by using an invar cavity attached to a programmable hot plate. The high-density samples possessed good microwave dielectric properties.

Origin of magnetocapacitance in chemically homogeneous and inhomogeneous ferrites.

The present work mainly focuses on the magnetodielectric (MD) effect in polycrystalline Ni0.9-yCuyZn0.1Fe1.98O3.97 (y = 0, 0.1, 0.2, 0.3, 0.4, 0.5) ferrite synthesized by a solid-state reaction method. Sintered samples showed the formation of CuO-rich grain boundary segregation for y≥ 0.2. The appearance of segregation made the present material chemically inhomogeneous and electrically heterogeneous. A negative MD response was observed in homogeneous ferrite for y = 0 and 0.1 due to lattice distortion (an intrinsic effect), whereas a positive MD response occurs in chemically inhomogeneous segregated ferrite (y≥ 0.2) due the collective effects of Maxwell-Wagner (MW) polarization with intrinsic magnetoresistance (an extrinsic effect).

Visceral adiposity and left ventricular remodeling: The Multi-Ethnic Study of Atherosclerosis.

BACKGROUND AND AIMS: Visceral fat (VF) is a source of pro-inflammatory adipokines implicated in cardiac remodeling. We sought to determine the impact of visceral fat and subcutaneous fat (SQ) depots on left ventricular (LV) structure, function, and geometry in the Multi-Ethnic Study of Atherosclerosis (MESA). METHODS AND RESULTS: We performed a post-hoc analysis on 1151 participants from MESA with cardiac magnetic resonance quantification of LV mass and LV mass-to-volume ratio (LVMV, an index of concentricity) and computed tomographic-derived SQ and VF area. Multivariable regression models to estimate association between height-indexed SQ and VF area (per cm(2)/m) with height-indexed LV mass (per height(2.7)) and LVMV were constructed, adjusted for clinical, biochemical, and demographic covariates. We found that both VF and SQ area were associated with height-indexed LV mass (ρ = 0.36 and 0.12, P < 0.0001, respectively), while only VF area was associated with LVMV (ρ = 0.28, P < 0.0001). Individuals with above-median VF had lower LV ejection fraction, greater indexed LV volumes and mass, and higher LVMV (all P < 0.001). In multivariable models adjusted for weight, VF (but not SQ) area was associated with LV concentricity and LV mass index, across both sexes. CONCLUSION: Visceral adiposity is independently associated with LV concentricity, a precursor to heart failure. Further study into the role of VF in LV remodeling as a potential therapeutic target is warranted.

Photoresponsive polyesters by incorporation of alkoxyphenacyl or coumarin chromophores along the backbone.

The synthesis and photochemical characterization of two classes of photoresponsive polyesters are described. These polyesters contain either alkoxyphenacyl or coumarin chromophores embedded along the polymer chain. The alkoxyphenacyl polyesters undergo efficient photoinduced chain scission upon irradiation at 300 nm in solution or as a nanoparticle suspension. At 254 nm the coumarin polyesters undergo polymer chain scission. Irradiation of the coumarin polyesters in solution at 350 nm results in both chain crosslinking and chain scission behavior, while irradiation of the coumarin polyesters as nanoparticles results in chain crosslinking. The properties of the alkoxyphenacyl and coumarin polyesters are influenced by the choice of diacid as seen from their thermal behavior. The use of glutamic acid enabled surface or bulk functionalization of the photoresponsive polymers. In addition, controlled release of Nile Red from coumarin polyester nanoparticles is demonstrated by modulation of the wavelength and intensity of irradiation.

Detection of Circulating Tumor Cells by Cell Block Technique in Malignant Tumors.

Introduction: Cancer is a leading cause of death worldwide and is a major cause of morbidity. To deal with this magnitude of cancers and their diagnostic and prognostics, a multitude of prognostic biomarkers for various cancers have been explored over the decades, with detection of circulating tumor cells (CTCs) in the peripheral blood being one of them. This study was undertaken to explore the routine procedure of cell block in the cytopathology lab to isolate and detect CTCs. Materials and Methods: In this cross-sectional study, 112 peripheral blood samples sent for routine blood investigations of various cancer patients were utilized for the preparation of cell block. The sections from the cell block were stained routinely and evaluated for the presence of CTCs. The statistical analysis was done using Mac Statplus software version 8.0. Results: The malignancies were tabulated as per the International Classification of Diseases for Oncology, third edition (ICD-O-3). The maximum number of cases were from C 50 (breast) - 41/112 (36.6%), followed by C15-C26 (Digestive organs) - 19/112 (16.9%), and C00-C14 (lip, oral cavity, and pharynx) - 18/112 (16.07%) cases. CTC was detected in six (5.35%) out of 112 cases, out of which three were from the breast and one each from category C6.9 (mouth), C32.0 (glottis), and C53.8 (cervix uteri). Conclusion: Among various advanced and molecular techniques available for the detection of CTCs, the cell block technique proves to be one of the effective methods, especially in resource-limited settings as these can further be utilized for additional diagnostic techniques similar to the ones employed for routine paraffin blocks.

Patterns of Failure After Prostate-Only Radiotherapy in High-Risk Prostate Cancer: Implications for Refining Pelvic Nodal Contouring Guidelines.

PURPOSE: To study prostate specific membrane antigen - positron emission tomography (Ga68PSMA-PETCT) based patterns of relapse at biochemical failure (BCF) after prostate-only radiotherapy (PORT) in high-risk (HR) prostate cancer and its implications on pelvic contouring recommendations. METHODS AND MATERIALS: Patients with clinico-radiological high-risk node-negative prostate cancer treated with curative PORT and androgen deprivation therapy (ADT), either within the POP-RT randomised trial or off trial, who underwent a Ga68PSMA-PETCT upon BCF were included. Patterns of regional and distant recurrence on Ga68PSMA-PETCT were studied. Pelvic nodal recurrences were mapped with reference to the superior border of pubic symphysis. Pelvic lymph nodal caudal border (PLNcb) recommendations in the published contouring guidelines (RTOGcb, GETUGcb, PIVOTALcb, NRGcb, GFRUcb) were evaluated. RESULTS: Of the total 262 patients screened, 68 eligible patients were included (POP-RT trial 35 patients; off-trial 33 patients). Median follow-up was 91 months (IQR, 72-117) and median time to BCF was 65 months (IQR, 49-83). Regional and distant recurrence was seen in 31 (46%) and 31 (46%) patients, respectively. Of the nodal recurrences, nearly half (46%, 14/31) had no distant metastases and 64% (20/31) had a failure in the common iliac nodal region. The lower-most nodal recurrence was 20 mm cranial to the top of pubic symphysis (RTOGcb, GETUGcb, GFRUcb) and 10 mm cranial to the PIVOTALcb. The PLNcb recommended by NRG guideline (NRGcb) had an inter-patient variability of 32 mm, ranging from 16 mm above to 16 mm below the top of pubic symphysis, and the lower most nodal recurrence ranged from 4 mm to 36 mm cranial to NRGcb. CONCLUSION: Pelvic failures accounted for a major proportion of recurrences after prostate-only radiotherapy, with the caudal most nodal recurrence being 20 mm cranial to the top of pubic symphysis. This could have implications in defining the caudal border of contouring recommendations.