Number Of Cycles Research Articles

Health State Prediction of Lithium-Ion Battery Based on Improved Sparrow Search Algorithm and Support Vector Regression

The state of health (SOH) prediction of lithium-ion batteries is a pivotal function within the battery management system (BMS), and achieving accurate SOH predictions is crucial for ensuring system safety and prolonging battery lifespan. To enhance prediction performance, this paper introduces an SOH prediction model based on an improved sparrow algorithm and support vector regression (ISSA-SVR). The model uses nonlinear weight reduction (NWDM) to enhance the search capability of the Sparrow algorithm and combines a mixed mutation strategy to reduce the risk of local optimal traps. Then, by analyzing the characteristics of different voltage ranges, the charging time from 3.8 V to 4.1 V, the discharge time of the battery, and the number of cycles are selected as the feature set of the model. The model’s prediction capabilities are validated across various working environments and training sample sizes, and its performance is benchmarked against other algorithms. Experimental findings indicate that the proposed model not only confines SOH prediction errors to within 1.5% but also demonstrates robust adaptability and widespread applicability.

Evaluation of Electrical Properties and Uniformity of Single Wall Carbon Nanotube Dip-Coated Conductive Fabrics Using Convolutional Neural Network-Based Image Analysis

This study proposes a convolutional neural network (CNN)-based image analysis method to evaluate the electrical properties and uniformity of conductive fabrics treated with single-walled carbon nanotube (SWCNT) dip-coating. The conductive fabric was produced by dip-coating cotton-blended spandex with SWCNT, and the surface images were scanned and preprocessed to obtain image data, while resistance measurements were conducted to obtain labels and build the dataset. SEM analysis revealed that as the number of dip-coating cycles increased, particle density and path formation improved. The CNN model learned the relationship between surface images and resistance values, achieving a high predictive performance, with an R-squared (R²) value of 0.9422. The model demonstrated prediction accuracies of 99.1792% for the coefficient of variation (CV) of uniformly coated fabrics and 96.8877% for non-uniformly coated fabrics. Additionally, p-value analysis of all fabric samples yielded a result of 0.96044, indicating no statistically significant difference between the predicted and actual values. The proposed CNN-based model can accurately evaluate the electrical uniformity of conductive fabrics, showing potential for contributing to quality control and process optimization in production.

PH-Switchable Surfactant-Based Microemulsions: Reversible Transition between Microemulsification and Demulsification Triggered by Suitable Acids and Bases.

pH-switchable surfactant-based microemulsions (SBMEs) are those that can switch reversibly between a monophasic state and a fully phase-separated state under the alternation of acids and bases, which is rarely reported. By using an equimolar mixture of sodium dodecyl sulfate and N,N-dimethyldodecylamine (SDS-C12A) as a pH-switchable surfactant, a pH-switchable SDS-C12A-based microemulsion (SDS-C12A-ME) has been fabricated for the first time. The main principles of the reversible switching are the reversible destruction/formation of the emulsifier, SDS-C12A-n-butanol, film at the oil-water interface due to the alternating protonation/deprotonation of C12A caused by acids and bases. The byproducts, H2O and salt, had an adverse effect on the reversibility of SDS-C12A-ME, with salt having a greater adverse effect than H2O. However, the reversibility of SDS-C12A-ME could be enhanced by suitable acids and bases. For example, for the same oil-in-water (O/W) SDS-C12A-ME, the number of switching cycles with HCl-choline hydroxide (ChOH) as a stimulus can be as large as 11, but only 3 with HCl-NaOH as a stimulus. By using the methyl methacrylate photochemical polymerization as a model, such a pH-switchable SBME can function as a recyclable reaction medium, while the resultant poly(methyl methacrylate) has a considerably reproducible molecular weight and narrow molecular weight distribution (polydispersity index is around 1.2) over three cycles. It is anticipated that the results presented in this work will serve as a reference for the design and fabrication of pH-switched SBMEs and also that such pH-switched SBMEs may have potential applications in practical technological areas such as industrial reaction media, drug delivery, microreactors, etc.

Uniaxial compressive behavior and unified damage constritutive model of various types of recycled coarse aggregate concrete under freeze-thaw action

To promote the application of recycled coarse aggregates in concrete structures in cold regions, this paper focuses on the damage evolution of natural coarse aggregate concrete (NAC), recycled concrete coarse aggregate concrete (RAC) and brick-concrete mixed recycled coarse concrete (MRC) under the freeze-thaw-load coupling action. The relative dynamic modulus of elasticity is used to assess the freeze-thaw damage degree of various types of concrete after 0, 25, 50, 75, 100, 125, and 150 freeze-thaw cycles, and a freeze-thaw damage evolution model is established. Uniaxial compression tests are conducted on concretes after different freeze-thaw cycles to study the effects of freeze-thaw cycles on the failure mode, peak stress, peak strain, static elastic modulus, and toughness of the specimens. The relationship between the freeze-thaw damage variable and stress-strain characteristic parameters is analyzed, and an unified damage constitutive model for various types of concrete under the freeze-thaw-load coupling action is further established. The results show that with the increase in the number of freeze-thaw cycles, the specimens exhibit vertical splitting failure under axial compression rather than typical shear failure. The freeze-thaw cycles reduce the ability of recycled concrete to resist deformation. The peak stress and static elastic modulus decrease with the increase of freeze-thaw cycles, while the peak strain and toughness increase with the increase of freeze-thaw cycles. NAC has the best frost resistance and axial compression bearing capacity, followed by RAC and MRC. The presence of recycled brick coarse aggregate further exacerbates the freeze-thaw damage of concrete. There is an interesting finding that the water absorption of recycled aggregates is well correlated with the shape parameters of the freeze-thaw damage model and the descending section of uniaxial compression damage constitutive in recycled concrete. When the descending branch of the stress-strain curve modified by water absorption of recycled aggregates, the proposed freeze-thaw-load coupling damage constitutive model demonstrates good predictive performance for the stress-strain behavior of recycled concrete.

Photon-number moments and cumulants of Gaussian states

We develop closed-form expressions for the moments and cumulants of Gaussian states when measured in the photon-number basis. We express the photon-number moments of a Gaussian state in terms of the loop Hafnian, a function that when applied to a (0,1)-matrix representing the adjacency of a graph, counts the number of its perfect matchings. Similarly, we express the photon-number cumulants in terms of the Montrealer, a newly introduced matrix function that when applied to a (0,1)-matrix counts the number of Hamiltonian cycles of that graph. Based on these graph-theoretic connections, we show that the calculation of photon-number moments and cumulants are #P-hard. Moreover, we provide an exponential time algorithm to calculate Montrealers (and thus cumulants), matching well-known results for Hafnians. We then demonstrate that when a uniformly lossy interferometer is fed in every input with identical single-mode Gaussian states with zero displacement, all the odd-order cumulants but the first one are zero. Finally, we employ the expressions we derive to study the distribution of cumulants up to the fourth order for different input states in a Gaussian boson sampling setup where K identical states are fed into an ℓ-mode interferometer. We analyze the dependence of the cumulants as a function of the type of input state, squeezed, lossy squeezed, squashed, or thermal, and as a function of the number of non-vacuum inputs. We find that thermal states perform much worse than other classical states, such as squashed states, at mimicking the photon-number cumulants of lossy or lossless squeezed states.

Influence of multiple compression phases during tableting of spray dried Saccharomyces cerevisiae on microbial survival and physical–mechanical tablet properties

The viability of probiotic microorganisms is essential for their health-promoting effects and must be preserved in the best possible way during the production of the final dosage form, such as tablets. This applies to both drying and tableting. Saccharomyces cerevisiae is spray-dried with suitable protective additives, which were identified in a previous study in which also the influence of the formulation during tableting was investigated. One aspect that has not yet been addressed is the effect of multiple compression, as it is typical with pre- and main compression when using rotary tablet presses. To investigate this, tablets are compressed up to five times. It is shown that when tablet strength and survival are considered together, the application of a pre- and main pressure does not have a significant effect. This facilitates the transferability of findings of compaction studies with a single compression phase. In addition, the data allow to consolidate the mechanism of inactivation of microorganisms during tableting found in previous studies by the same authors. This is based on the porosity reduction, whereby it is shown in the present study that it is irrelevant how this reduction is achieved (change in compression stress or the number of compression cycles).

HPB O01 - Colonization of bile with gammaproteobacteria reduces survival after surgery for pancreatic cancer in patients receiving gemcitabine-based adjuvant chemotherapy

Abstract Background Evidence suggests that the biliary microbiome influences the progression of pancreatic ductal adenocarcinoma (PDAC) in patients undergoing adjuvant chemotherapy. Specifically, Gammaproteobacteria (GPB) has been shown to have the potential to develop mutations which can metabolise gemcitabine into an inactive form. This study hypothesised that GPB influences survival in patients with PDAC undergoing adjuvant gemcitabine-based chemotherapy following surgery. Method This was a retrospective study of patients undergoing pancreatoduodenectomy from 2010 to 2020. Associations between patient and tumour characteristics, survival data, and results of intraoperative bile cultures (GPB+ or GPB-) were investigated. Analysis of patients matched by chemotherapy regimen and numbers of cycles of adjuvant therapy was also performed. Survival was analysed using Kaplan–Meier curves and Cox regression analysis. Results Analysis of 359 patients revealed that adjuvant gemcitabine-based therapy improved overall survival (OS). Patients who receive gemcitabine-based chemotherapy with a GPB+ biliary culture had a shorter OS compared to those who were GPB-, and a median survival of 17.9 vs 26.1 months, P=0.006. After matching for key chemotherapy variables, survival was greater in the GPB- group 26.8 vs 19.8, P=0.016. This association was not seen among patients who received no adjuvant therapy or non-gemcitabine based therapy. Conclusion Patients receiving gemcitabine-based chemotherapy after surgery are likely to have reduction in OS if they have a biliary culture positive for GPB.

Research on aging mechanism and capacity attenuation of automotive lithium-ion batteries

In order to investigate the internal mechanism and the variation law of capacity attenuation of LIBs, a simplified electrochemical model of the LIBs was established using the nickel-cobalt-aluminum LIBs as the research object, and the aging model of solid electrolyte interface SEI growth and lithium evolution was added to simulate the electrochemical behavior of the batteries. The results showed that the porosity of the anode/diaphragm reduced continually at the start of the cycle, while the SEI film grew continuously. The loss of active materials accelerated as the number of cycles increased, while the side reaction of lithium development continued. Finally, the aging mechanism was confirmed by using microscopic morphology. The results show that the negative particles are obviously crushed and contain white deposited substances. The formation of these compounds increases the oxygen content, reduces the carbon content, reduces the porosity of the electrode, increases the overpotential of the electrolyte transport, and becomes the main reason for the attenuation of the battery life. Finally, the positive particles expand and break, which leads to the sudden reduction of the battery capacity. This study determined the evolution process of aging mechanism in the whole life cycle, and provided a theoretical basis for the establishment of mechanism aging model.

Laminar and turbulent flow effects in high-pressure homogenization of liposomes and perfluorocarbon nanoemulsions

Since flow characteristics are still largely unexplored for high-pressure homogenization, we investigated particle break-up at different Reynolds numbers and transition ranges in two channels (Y- and Z-channel). While the channel geometries are often treated as “black boxes”, opening the channels and measuring their geometries allowed a detailed analysis of flow conditions. Transitions from laminar to turbulent flow for pressures of 250–2,000 bar have measurable effects on the sizes of perfluorocarbon (PFC)-nanoemulsion droplets emulsified by phospholipids processed simultaneously in liposomal conformation. Laminar flow has a higher size-reducing rate with growing pressure compared to turbulent flow and leads to a minimum in polydispersity. A density-driven sucrose gradient allows differential analysis of size-reducing effects on liposomes and PFC-nanoemulsion droplets separately. Liposomes can be broken up in both laminar and turbulent flow at the same size reduction rate. In contrast, emulsion droplets have much smaller size reduction rates in turbulent flow and need sufficient emulsifiers, made available by liposomal break-up, to enable size decreases. Repetitive homogenization is only effective for a limited number of cycles. Beyond this threshold, size distributions remain similar or can be deteriorated because of increased particle collisions and aggregation or coalescence effects.

The effect of different mission profiles and ambient temperature on the lifetime of boost converter IGBT with a robust controller in a hybrid electric vehicle

AbstractThe reliability of power electronic converters is one of the essential issues in designing of electric vehicles. This paper estimates the lifetime of the boost converter switch by Semikron and Coffin‐Manson models for two common failure mechanisms of Bond wire and Base plate solder, respectively. Four mission profiles based on the Artemis standard are applied to hybrid electrical vehicle model to determine unidirectional output power. Kharitonov's theory is used to design a robust controller to handle the uncertainty raised by different power cycles of the electric vehicle and the parameters of the converter during simulation. Stability of converter is achieved during simulation by identifying simple proportional integral controller coefficients with Kharitonov's theorem. A prototype 230 W boost converter is designed and utilized to validate average model and switch loss calculation relationships. The lifetime results indicate that the number of cycles, and the average and the maximum junction temperature have a more impact than the duration of the drive cycle on the lifetime of the converter. A mixed mission profile is considered to investigate the effect of sudden change in driving modes and speed on total consumed life and lifetime to enhance the study's applicability. Lifetime of switch is decreased significantly in mixed mode in comparison with other mission profiles in the same driving time. Furthermore, the motorway mission profile has 53%, 39.6%, and 160% less total consumed life in comparison with the urban, rural and mixed mission profiles, respectively. In addition, the effect of ambient temperature changes on IGBT lifetime has been investigated for four mission profiles. While motorway had the least total consumed life in 25°C, the urban had better performance in comparison with other mission profiles from 25 to 55°C.

Prognostic Impact of Adjuvant Immunotherapy in Patients With Resectable NSCLC After Neoadjuvant Chemoimmunotherapy: A Brief Report

ObjectiveThe potential survival benefits of adjuvant immunotherapy for resectable NSCLC after neoadjuvant chemoimmunotherapy, and the optimal number of adjuvant immunotherapy cycles, remain uncertain. This study aims to evaluate the prognostic impact of adjuvant immunotherapy and determine the optimal number of cycles. MethodsA total of 438 patients who received neoadjuvant chemoimmunotherapy between August 2019 and June 2022 across four hospitals were enrolled in this study, with a median follow-up time of 31.3 months. Recurrence-free survival (RFS) and overall survival (OS) were estimated using Kaplan-Meier methods and tested by log-rank test. Unstratified Cox proportional hazards models were fitted to the subgroups. ResultsIn this multi-center cohort, 29.7% of patients (n = 130) achieved a pathologic complete response. Patients who received adjuvant immunotherapy experienced significant survival benefits compared with those who did not (RFS: hazard ratio [HR] = 0.63, 95% confidence interval: 0.41–0.98, p = 0.037; OS: hazard ratio = 0.27, 95% confidence interval: 0.13–0.57, p < 0.001). Subgroup analyses found that patients with a squamous histologic type, positive PD-L1 expression, and those with a major pathologic response particularly benefited from adjuvant immunotherapy. In addition, we found that six cycles of adjuvant immunotherapy served as a threshold for better prognostic differentiation, suggesting that six or more cycles may be more beneficial. ConclusionsOur study found that the addition of adjuvant immunotherapy to neoadjuvant chemoimmunotherapy is significantly associated with improved RFS and OS in patients with resectable NSCLC. We also identified that six cycles of adjuvant immunotherapy may be the optimal regimen for these patients.

Enhanced photoelectrochemical performance of BiVO4 nanoparticle-modified TiO2 nanorod arrays

A wide-spectrum responsive one-dimensional (1-D) TiO2@BiVO4 heterostructured array (HA) photoelectrode was successfully prepared using an easy hydrothermal approach and subsequent stepwise spin–coating. BiVO4 nanoparticles (NPs) were uniformly coated onto TiO2 nanorods (NRs) surface. The photoelectrochemical (PEC) performance can be optimized by controlling the number of the stepwise spin-coating cycles. The appropriate stepwise spin-coating cycles number was crucial for obtaining a perfect TiO2@BiVO4 HA photoelectrode with enhanced PEC performance. Compared with the bare TiO2 NR array (NRA) photo-electrode, TiO2@BiVO4-8 HA photoelectrode (acquired in 8 cycles) exhibited the significantly improved photocurrent density (from 0.19 to 1.21 mA·cm−2 at 1.0 V vs. the saturated calomel electrode (SCE), approximately a 6-fold increase for that of the pure TiO2 NRA photoanode), increased electron lifetime (from 1.26 to 6.09 ms), reduced initial potential (from – 0.22 V to – 0.57 V (vs. SCE)), and enhanced photoconversion efficiency (from 6.3 % to 32.7 % at 360 nm). The performance improvement is given the credit to the unique 1-D well-arranged heterostructure of the photoelectrodes and the appropriate BiVO4 NPs coating amount onto TiO2 NRs surface.

Reliability analysis of DDV and SPM in BOP-based Weibull model and expand fault dataset using deep learning

The hydraulic systems of deepwater Blowout Preventers (BOPs) are crucial for ensuring the reliability and safety of offshore oil and gas extraction operations. A functional failure can lead to uncontrolled blowouts, resulting in casualties and significant economic losses on the rig. The Direct Drive Valve (DDV) and the Subsea Plated Mounted (SPM) valve are key components that help maintain the proper functioning of the hydraulic system in deepwater BOPs. This study begins by utilizing the Weibull analysis method to assess the reliability of the DDV and SPM valves using limited fault data samples. To enhance the accuracy of predictions, Weibull parameters are estimated through various methods, including Maximum Likelihood Estimation (MLE), Least Squares Estimation (LSE), and a combination of Correlation Coefficient Optimization with Support Vector Regression (CCO + SVR).Given the challenges in gathering extensive fault data for DDV and SPM valves—due to complex subsea environments, cost constraints, time limitations, and other factors—this study proposes a method employing a Back Propagation Neural Network (BPNN) model to augment the limited fault data samples. To ensure the reliable operation of the DDV and SPM valves, preventive maintenance cycles are established at 2840 and 7550 operations, respectively. At the same reliability level, as the number of operational cycles increases, the remaining service life of the valves gradually decreases, leading to a higher probability of failure over a shorter timeframe. The Mean Remaining Life (MRL) of the DDV and SPM valves, corresponding to different operational times, is analyzed, providing essential reference points for their usage and maintenance. When the extended data sample is utilized for reliability evaluation, the reliability characteristics of the small fault data samples are effectively reflected, and the parameter prediction error remains low. This indicates that the extended data sample is more suitable for reliability evaluation.

Critical length parameter of HDPE and its use in fatigue lifetime predictions

The contribution describes the fatigue lifetime predictions of polyethylene notched specimens based on the theory of critical distance. The approach uses the line method, which averages the axial stress over the critical distance. The critical distance is determined from experimental data of Cracked Round Bar (CRB) specimens and specimens with a model notch. From these two sets of experimental fatigue data and corresponding axial stress distributions, the critical distance is determined. The critical distance depends on the number of cycles to failure and notch radius. For this reason, the critical distance is modified by the ratio of stress concentration factors and the modified distance is used for fatigue lifetime predictions of notched specimens with various notch radii. Using this approach significant savings in testing time can be achieved. CRB fatigue tests are commonly used tests for ranking PE pipe grades and are easily available. Adding the fatigue tests of notched specimens with a model notch, the critical parameter can be found, and fatigue lifetime predictions of various notches can be calculated.

Sustaining 500,000 Folding Cycles Through Bioinspired Stress Dispersion Design in Sodium‐Ion Batteries

AbstractDeveloping super‐foldable electronic materials and devices presents a significant challenge, as intrinsic conductive materials are unable to achieve numerous true‐folding operations (super‐foldable) due to limitations from short‐range forces of chemical bonds. Consequently, super‐foldable batteries remain unexplored. This work focused on sodium‐ion batteries as a breakthrough point to advance super‐foldable devices. By employing a “2+1” bioinspired strategy, we stepwise designed and assembled super‐foldable components, from substrates to electrodes, and to ultimately device. This bioinspired approach completely disperses folding stress and thus prevents the breakage of chemical bonds, enabling the successful fabrication of the first super‐foldable ion battery. This battery can withstand true‐folding at any angle, in any direction, and for an unprecedented number of cycles—far outperforming current foldable phones with hinge structures. Remarkably, after 500,000 true‐folding cycles, the battery's microstructure remains intact with no significant degradation of electrochemical performance. Real‐time dynamic folding observations reveal an M‐shaped folding structure within the bioinspired materials, which effectively disperses stress via bulged layers, dispersed arcs, and slidable microgrooves that work together across different directions and dimensions to achieve super‐foldability. Mechanical simulations vividly verify this principle. This work represents a breakthrough in super‐foldable devices, offering valuable insights and promoting practical application for future super‐foldable devices.

Experiment and prediction of enhanced gas storage capacity in depleted gas reservoirs for clean energy applications

Utilizing depleted gas reservoirs for gas storage is the most efficient method. However, the impact of multi-cycle injection-production and water invasion on rock properties and gas-water seepage dynamics remains unclear. This study investigates such reservoirs' multi-cycle stress sensitivity and gas-water displacement behavior. Results show that multi-cycle injection-production and water invasion increase the stress sensitivity of the gas and damage gas storage space and seepage channels. This study also proposed a new unsteady gas-water relative permeability testing method and a prediction model based on in-situ X-ray CT scanning, improving measurement accuracy by 30 %. The results found that the gas's relative permeability is directly proportional to the injection rate and inversely proportional to the initial gas saturation. A gas-water relative permeability model was established, demonstrating that gas-water interference intensifies as the number of cycles increases. In a gas-water transition zone in depleted gas reservoirs, gas relative permeability damage reaches 81 %, reducing the movable pore space and impacting injection-production rates and capacity. This study offers valuable recommendations for optimizing production and dynamic prediction in depleted gas reservoirs, contributing to clean energy applications.

Abstract 4137448: Systemic Heparin Administration Does Not Inhibit microRNA Amplification in Patients with Myocardial Infarction

Purpose: MicroRNAs (miRs) have been proposed as biomarkers of myocardial infarction (MI), but prior evidence has demonstrated that heparin, commonly administered to patients presenting with MI, inhibits amplification during quantitative PCR (qPCR). The purpose of this study was to determine whether qPCR amplification of miRs is reduced in plasma of patients receiving heparin and if heparinase reverses this effect. Methods: Blood samples were collected and plasma recovered from patients with normal coronary arteries who had undergone CT coronary angiography ( N=5 ) or who had received intravenous heparin at the time of invasive coronary angiography( N=8 ). Blood was also collected at the time of invasive coronary angiography from patients presenting with ST elevation MI ( N=9 ). RT-qPCR was performed to quantify levels of 84 cardiac miRs, and Cel-miR-39-3p was utilized as a spike-in control. MiR qPCR was also performed following the addition of heparinase to plasma from 2 patients without MI treated with heparin and 2 patients presenting with MI who had received heparin. Results: Mean age of patients was 57 years, and 55% of patients were male. As compared with control patients, the cycle number for cel-miR-39-3p was significantly increased for patients receiving heparin (Figure 1a). No difference was seen in levels of cel-39-3p in heparin-treated patients with respect to the presence or absence of MI. Cel-miR-39-3p cycle times decreased when heparinase was added to samples from heparin-treated patients (Figure 1b). In contrast, heparin did not increase cycle times in any of the cardiac miRs tested, and cycle times decreased even further for miRs 499a-5p and 208b-3p in patients with MI (Figure 2). Conclusions: Systemic heparin treatment inhibits qPCR amplification of cel-mir-39-3p but does not inhibit endogenous miR amplification under these conditions. MiRs 499a-5p and 208b-3p are potentially important candidates for MI detection and quantification.

Damage indicators evolution during cyclic loading of composite plate with hole

Novel experimental method, which provides quantitative description of damage indicators evolution caused by fatigue loading of composite specimens with stress concentrators, was developed. Damage parameters are derived as deformation response to artificial notch inserting. This notch is extended from the edge of central through hole in plane rectangular specimen under constant external load. Current values of damage indicators are obtained at different stages of fatigue loading. These data reveal dependencies of required parameters on loading cycle number. The damage accumulation function for involved cycle range is quantitatively constructed on this base. It is found that this function is related to the first stage of the process investigated. The results obtained represent the essential link in the design of further experiments.

CTNI-33. EARLY COMPLETE RESPONSE MIGHT NOT BE AN INDICATOR OF LONGER PROGRESSION-FREE SURVIVAL IN NEWLY-DIAGNOSED PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMA WITH A COMPLETE RESPONSE BY MTX-BASED INDUCTION THERAPY

Abstract Primary central nervous system lymphoma (PCNSL) is an extra-nodal non-Hodgkin lymphoma solely arising from the central nervous system including eyes. While 70% of patients with newly-diagnosed PCNSL achieve a complete response (CR) after R-MPV, the current standard of care MTX-based induction therapy, recurrence yet frequently occurs (~50%) and clinical factors related to failure are not well defined. Early complete response is associated with lower recurrence rate in various cancers. In this study, we conducted a retrospective, single-institution study to investigate whether early complete response was associated with recurrence in PCNSL. Newly-diagnosed PCNSL patients treated with R-MPV at the authors’ institution between 2011 and 2022 were identified, and progression-free survival (PFS), overall survival (OS) were analyzed along with number of chemotherapy cycles required to achieve a CR or CR unconfirmed (CRu). In total of 92 patients treated with R-MPV identified, 68 (75%) patients achieved a CR or CRu. Among patients who achieved CR or CRu, a median total of seven (1-8) R-MPV cycles were delivered. The median cycle required to achieve CR or CRu was five (1-8). Consolidation whole brain radiation therapy (WBRT) was given to 29 younger patients (median age: 63), while 39 older patients (median age: 74) were treated without WBRT. The number of chemotherapy cycles required to achieve CR or CRu was not associated with PFS or OS in all ages. However, requiring six or more chemotherapy cycles to achieve CR or CRu was associated with longer PFS (p=0.046) in patients treated without WBRT. These data suggest that early complete response might not be indicative of superior survival outcome in newly-diagnosed PCNSL treated without consolidation WBRT. Persisting enhancing lesions during chemotherapy could lead to treatment intensification through delivering greater number of chemotherapy cycles, which might have conferred longer PFS in these patients.

CTNI-73. ASSESSMENT OF MOLECULAR ALTERATIONS IN NEWLY DIAGNOSED GBM MGMT-UNMETHYLATED PATIENTS TREATED WITH VAL-083

Abstract Glioblastoma (GBM) commonly features molecular alterations in the TERT, EGFR, PTEN, and TP53 genes, which contributes to uncontrolled cell growth, evasion of apoptosis, and enhanced tumor cell survival. VAL-083 is a bi-functional DNA-targeting agent which rapidly induces inter-strand DNA cross-links at N7 and O6-guanine inducing double-strand breaks causing cell death independently of MGMT DNA repair and DNA mismatch repair deficiency. VAL-083 was evaluated in an open-label, biomarker-driven, phase 2 trial in MGMT-unmethylated, bevacizumab-naïve GBM patients. The molecular profile of tumors from a newly diagnosed GBM patient subgroup who received VAL-083 alone after chemo-radiation with concurrent TMZ, was determined in order to correlate with clinical outcomes. Thirty-four (34/36, 94.4%) patients who received 30 mg/m2 VAL-083 (days 1-3 of 21-day cycle) had available next-generation sequencing data on their primary tissue. Patient median age was 54.8 years (5-95pth: 29.8-66.0), median KPS was 90 (5-95pth: 80-100) and 58.8% were males. The median number of cycles of VAL-083 was 7.5 (5-95pth: 1-12). There were 5 dose reductions due to toxicity. The median time to progression (PFS) and overall survival (OS) were 9.2 mo (95%CI: 7.6-10.2) and 16.5 mo (95%CI: 13.3-19.0), respectively. The mean number of molecular alterations was 3.9 (5-95pth 1-8). Six (17.6%) patients had gene fusions. The most common molecular alterations were TERT promoter (91.2%), EGFR amplification (amp) (52.9%), PTEN (50.0%), EGFR (20.6%), and TP53 (20.6%). Additional alterations (in ≥2 patients; 6%) included EGFR-EGFR (EGFRvIII), BRCA2, CDKN2A/B, CDK4/6 amp, MDM2/4 amp, NF1, NOTCH1, PIK3R1 and RB1. While TP53 mutations showed a trend as predictors for time to progression (P 0.027), this was not observed with OS. None of the molecular alterations were predictors of number of treatment cycles or dose reductions. No specific molecular alterations were identified that predicted either improved or poorer patient outcome, during treatment with VAL-083. Clinicaltrials.gov identifier: NCT02717962.