Variable Filter Research Articles

A new smooth variable structure Tobit filter for systems with censored measurements and model parameters uncertainty

The smooth variable structure filter (SVSF) is an effective state estimation strategy for systems with model parameters uncertainty. The superiority of SVSF, however, depends on accurate sensor measurements. In practice, the accuracy of traditional SVSF algorithm will be degraded or even diverge for censored measurements. To solve this problem, in this paper, firstly, the Tobit censored model is introduced to describe censored phenomenon for systems with model parameters uncertainty and censored measurements. The innovation, residual, innovation covariance and state prediction error cross-covariance are revised based on cumulative probability density. Then, the near optimal smooth boundary layer (SBL) is recalculated based on the minimum trace principle of estimation error covariance. A robust filter gain is redesigned based on the convergence of estimation error absolute, and the necessary conditions for the convergence of the proposed filter are proved. In the end, oscillators, distributed target tracking and the Udacity self-driving data-set are used to verify that the proposed algorithm has higher accuracy and better robustness under model parameters uncertainty and censored measurements.

Genetic blueprint of congenital muscular dystrophies with brain malformations in Egypt: A report of 11 families

Congenital muscular dystrophies (CMDs) are a group of rare muscle disorders characterized by early onset hypotonia and motor developmental delay associated with brain malformations with or without eye anomalies in the most severe cases. In this study, we aimed to uncover the genetic basis of severe CMD in Egypt and to determine the efficacy of whole exome sequencing (WES)-based genetic diagnosis in this population. We recruited twelve individuals from eleven families with a clinical diagnosis of CMD with brain malformations that fell into two groups: seven patients with suspected dystroglycanopathy and five patients with suspected merosin-deficient CMD. WES was analyzed by variant filtering using multiple approaches including splicing and copy number variant (CNV) analysis. We identified likely pathogenic variants in FKRP in two cases and variants in POMT1, POMK, and B3GALNT2 in three individuals. All individuals with merosin-deficient CMD had truncating variants in LAMA2. Further analysis in one of the two unsolved cases showed a homozygous protein-truncating variant in Feline Leukemia Virus subgroup C Receptor 1 (FLVCR1). FLVCR1 loss of function has never been previously reported. Yet, loss of function of its paralog, FLVCR2, causes lethal hydranencephaly-hydrocephaly syndrome (Fowler Syndrome) which should be considered in the differential diagnosis for dystroglycanopathy. Overall, we reached a diagnostic rate of 86% (6/7) for dystroglycanopathies and 100% (5/5) for merosinopathy. In conclusion, our results provide further evidence that WES is an important diagnostic method in CMD in developing countries to improve the diagnostic rate, management plan, and genetic counseling for these disorders.

Significance Associated with Phenotype Score Aids in Variant Prioritization for Exome Sequencing Analysis

Several in silico annotation-based methods have been developed to prioritize variants in exome sequencing analysis. This study introduces a novel metric, the Significance Associated with Phenotypes (SAP) score, which generates a statistical score by comparing an individual's observed phenotypes against existing gene-phenotype associations. To evaluate the SAP score, a retrospective analysis was performed on 219 exomes. Among them, 82 family-based and 35 singleton exomes had at least one disease-causing variant explaining the patient’s clinical features. SAP scores were calculated, and the rank of the disease-causing variant was compared to a known method, Exomiser. Using the SAP score, the known causative variant was ranked in the top 10 retained variants for 94% (77/82) of the family-based exomes and in the first place for 73% of these cases. For singleton exomes, the SAP score analysis ranked the known pathogenic variants within the top 10 for 80% (28/35) of the cases. The SAP score, which is independent of detected variants, demonstrates comparable performance to Exomiser, which considers both phenotype and variant-level evidence simultaneously. Among 102 cases with negative results or variants of uncertain significance, SAP score analysis revealed two cases with a potential new diagnosis based on rank. The SAP score, a phenotypic quantitative metric, can be utilized in conjunction with standard variant filtration and annotation to enhance variant prioritization in exome analysis.

Novel Time-Saving Technique to Measure the 2D Complex Profile of Spectral Transmittance of Linearly Variable Filters and Assessing Homogeneity of Optically Transparent Materials

Emerging technologies for coating new types of filters, such as linearly variable bandpass filters, urges new kind of measurement systems requiring accurate and time-saving spatially resolved transmittance measurements. On the other hand, one of the main uses of coated filters is standardization use; e.g., as certified reference materials (CRMs) for transmittance and absorbance standards. In this case, the homogeneity assessment is of great interest. To do such measurements with low uncertainty, spatial scanning methods using reference double-beam spectrophotometers are routinely used. High time consumption and relatively high-cost are disadvantages of this traditional method. In this work, we propose a new system based on an imaging technique. The newly developed system comprises a quartz tungsten halogen (QTH)-based illuminator, with collimator and coupling optics, a double-grating monochromator, customized integrating sphere, and scientific highly digitized, high-resolution and dynamic range Si-based CCD (monochrome) camera. The system is time-saving: in one-shot we may measure the spatial transmittance distribution of the samples (e.g. filters) without separately measuring the reference (air), which has many instability issues. Validation measurements using standard filters are presented. Systematic errors may be studied and corrected for. Many types of filters and liquids, for instance chemical reference materials (RMs), may be measured and reported. Uncertainty of spatial, spectral and radiometric components are studied carefully and estimated. The combined uncertainty evaluation has shown that relatively low uncertainty levels may be achieved, specially in the visible range (U < 1 %, k=2 ). Spatially-resolved data with different curves at different positions (spatial points) are shown in the spectral range of 380 nm through 950 nm. The combined uncertainties at some spectral points are presented and proved to be sample- and wavelength-dependent at all the points in the field-of-view (FOV) of the CCD camera.

Method for the height measurement of agricultural implements based on variable parameter Kalman filter

Method for the height measurement of agricultural implements based on variable parameter Kalman filter

Sliding mode sensorless control of wind turbine pitch motor with ESO feedforward compensation in the offshore wind power system

In order to improve the dynamic performance of the control system, a variable frequency sliding mode sensorless control strategy based on Extended State Observer (ESO) feedforward compensation was proposed in order to improve the disturbance and jitter problems of pitch motors in offshore wind power generation systems. The fast exponential reaching law is designed in the velocity loop, and the integrated sliding surface is adopted, which reduces the steady-state error of the traditional sliding surface and weakens the jitter phenomenon of the moving point on the sliding surface. The traditional sliding mode observer is improved, and the variable cut-off frequency filter is used instead of the low-pass filter in the filtering process to filter the signals of each speed band. At the same time, in order to estimate the disturbances in the system, the Linear Extended State Observer (LESO) is designed to observe and compensate for the unknown disturbances, which improves the robustness of the system. The simulation results show that the control strategy in this paper solves the problems of traditional Sliding Mode Control (SMC), which not only shortens the response time of the system, but also significantly improves the anti-disturbance performance of the system, and the overall effect is significantly improved.

Predictors for improvement in personality functioning during outpatient psychotherapy: A machine learning approach within a psychodynamic psychotherapy sample.

Since its introduction in the diagnostic manuals DSM-5 and ICD-11, the construct of personality functioning has gained increasing attention. However, it remains unclear which factors might predict improvement in personality functioning. We examined a sample of 648 completed psychodynamic psychotherapies conducted by 172 therapists at the Heidelberg Institute for Psychotherapy. A machine learning approach was used to filter for variables that are relevant for the prediction of the improvement of personality functioning from a broad data set of variables collected at the beginning of each psychodynamic psychotherapy. On average, we found an improvement of 0.24 (SD = 0.48) in the OPD-SQ. This corresponds to a medium effect in the improvement of personality functioning. Patients with initially high impairment experienced particularly large improvements. Overall, we found a large number of variables that proved to be predictive for the improvement of personality functioning. Limitations in social activity due to physical and emotional problems proved to be one of the most important predictors of improvement. Most of the effect sizes were small. Overall, the improvement in personality functioning during psychotherapy is determined more by the sum of a large number of small effects than by individual variables. In particular, variables that capture social areas of life proved to be robust predictors.

Systematic transcriptomic analysis and temporal modelling of human fibroblast senescence.

Cellular senescence is a diverse phenotype characterised by permanent cell cycle arrest and an associated secretory phenotype (SASP) which includes inflammatory cytokines. Typically, senescent cells are removed by the immune system, but this process becomes dysregulated with age causing senescent cells to accumulate and induce chronic inflammatory signalling. Identifying senescent cells is challenging due to senescence phenotype heterogeneity, and senotherapy often requires a combinatorial approach. Here we systematically collected 119 transcriptomic datasets related to human fibroblasts, forming an online database describing the relevant variables for each study allowing users to filter for variables and genes of interest. Our own analysis of the database identified 28 genes significantly up- or downregulated across four senescence types (DNA damage induced senescence (DDIS), oncogene induced senescence (OIS), replicative senescence, and bystander induced senescence) compared to proliferating controls. We also found gene expression patterns of conventional senescence markers were highly specific and reliable for different senescence inducers, cell lines, and timepoints. Our comprehensive data supported several observations made in existing studies using single datasets, including stronger p53 signalling in DDIS compared to OIS. However, contrary to some early observations, both p16 and p21mRNA levels rise quickly, depending on senescence type, and persist for at least 8-11days. Additionally, little evidence was found to support an initial TGFβ-centric SASP. To support our transcriptomic analysis, we computationally modelled temporal protein changes of select core senescence proteins during DDIS and OIS, as well as perform knockdown interventions. We conclude that while universal biomarkers of senescence are difficult to identify, conventional senescence markers follow predictable profiles and construction of a framework for studying senescence could lead to more reproducible data and understanding of senescence heterogeneity.

The Fusion of Infrared and Visible Images via Feature Extraction and Subwindow Variance Filtering

This paper presents a subwindow variance filtering algorithm for fusing infrared and visible light images, with the goal of addressing challenges related to blurred details, low contrast, and missing edge features. First, images to be fused are subjected to multilevel decomposition using a subwindow variance filter, resulting in corresponding base and multiple detail layers. PCANet extracts features from the base layer and obtains corresponding weight maps that guide the fusion process. A saliency measurement method is proposed for detail‐level fusion to extract saliency maps from the source image. The saliency maps should be compared in order to obtain the initial weight map, which is then optimized using guided filtering technology to guide the fusion of detail layers. Finally, the information of the base layer and the detail layer after fusion is superimposed to obtain an ideal fusion result. The proposed algorithm is evaluated through subjective and objective measures, including information entropy, mutual information, multiscale structural similarity measurement, standard deviation, and visual information fidelity. The results demonstrate that the proposed algorithm achieves rich detail information, high contrast, and good edge information retention, making it a promising approach for infrared and visible image fusion.

Identification of novel candidate genes associated with non-syndromic tooth agenesis in Mongolian families

ObjectivesThis study aimed to identify genetic variants associated with non-syndromic tooth agenesis (TA) in nine families from Mongolia using whole-exome sequencing (WES) and bioinformatics analysis.Material and methodsThe study enrolled 41 participants, including three inherited and six non-inherited families. WES analysis was performed on 14 saliva samples from individuals with non-syndromic TA. The potential candidate genes were identified through variant filtering and segregation analysis. The filtered variants were then analyzed in silico mutation impact analysis.ResultsWES analysis identified 21 variants associated with TA, and 5 of these variants met all filtering criteria. These variants were located in the exome region of MAST4, ITGA6, PITX2, CACNA1S, and CDON genes. The variant in PITX2 was found in eight participants from inherited and non-inherited families, while the MAST4 variant was identified in 6 participants from inherited families.ConclusionsThe study identified various genetic variant candidates associated with TA in different family groups, with PITX2 being the most commonly identified. Our findings suggest that MAST4 may also be a novel candidate gene for TA due to its association with the Wnt signaling pathway. Additionally, we found that five candidate genes related to focal adhesion and calcium channel complex were significant and essential in tooth development.Clinical relevanceIdentifying new pathogenic genes associated with TA can improve our understanding of the molecular mechanisms underlying the disease, leading to better diagnosis, prevention, and treatment. Early detection of TA based on biomarkers can improve dental management and facilitate orthodontic and prosthetic treatment.

Research on battery state of charge estimation based on variable window adaptive extended Kalman filter

Battery state of charge (SOC) estimation is one of the indispensable functions in the battery management system. Among them, the Kalman filter series of algorithms are widely used in the battery SOC estimation process. The adaptive extended Kalman filter uses the difference between the measured voltage and the estimated voltage (error innovation) as the innovative covariance matrix update noise in battery SOC estimation. However, the general adaptive Kalman filter does not consider the error innovation in the estimation process. The change. This will lead to inaccurate battery SOC estimation. In order to solve this problem, we proposes a variable window Kalman filter algorithm that takes into account the changes in the error innovation sequence. The algorithm updates the innovation covariance matrix according to the change of error innovation to improve the accuracy of SOC estimation. The results show that compared with the extended Kalman filter and the fixed window Kalman filter, its calculation efficiency is also improved while its accuracy is improved. Finally, its accuracy is verified under different initial parameters, and the study shows that the algorithm proposed in this article is robust.

An adaptive cepstrum feature representation method with variable frame length and variable filter banks for acoustic emission signals

Acoustic emission technology is widely employed in defect detection, structural health monitoring, fault diagnosis, and other applications due to its benefits of non-contact, real-time, sensitivity, and flexibility. To implement efficient and timely intelligent monitoring, it is crucial to promptly and precisely gather the time-varying properties in the non-stationary acoustic emission signals. The current work proposes an adaptive cepstrum feature representation method that combines variable frame length and variable filter bank. The variable frame length is implemented based on the spectral distribution correlation, and the optimal frame length and frame rate are selected by iterative operations. The variable filter bank, on the other hand, characterizes the local measure features of variable frame length signals by setting dynamic weight distributions. The proposed adaptive cepstrum algorithm can be used as an auxiliary tool to initially analyze complex non-stationary signals, and thus effectively identify the time-varying and frequency components in acoustic emission signals. The superiority of the proposed method has been confirmed on simulation data. Furthermore, the practical performance of the proposed method is evaluated and illustrated based on the burst signal from laser shock peening processing and the mixed signal from pipeline leakage. The proposed method can be extended to other broadband signals and can be used for feature pre-processing before deep learning network modeling to improve recognition accuracy due to its high time–frequency resolution.

Energy efficient enhanced all pass transformation fostered variable digital filter design based on approximate adder and approximate multiplier for eradicating sensor nodes noise

Energy efficient enhanced all pass transformation fostered variable digital filter design based on approximate adder and approximate multiplier for eradicating sensor nodes noise

Powerline interference reduction in ECG signals using variable notch filter designed via variational mode decomposition

Powerline interference reduction in ECG signals using variable notch filter designed via variational mode decomposition

A Fast, Reproducible, High-throughput Variant Calling Workflow for Population Genomics.

The increasing availability of genomic resequencing data sets and high-quality reference genomes across the tree of life present exciting opportunities for comparative population genomic studies. However, substantial challenges prevent the simple reuse of data across different studies and species, arising from variability in variant calling pipelines, data quality, and the need for computationally intensive reanalysis. Here, we present snpArcher, a flexible and highly efficient workflow designed for the analysis of genomic resequencing data in nonmodel organisms. snpArcher provides a standardized variant calling pipeline and includes modules for variant quality control, data visualization, variant filtering, and other downstream analyses. Implemented in Snakemake, snpArcher is user-friendly, reproducible, and designed to be compatible with high-performance computing clusters and cloud environments. To demonstrate the flexibility of this pipeline, we applied snpArcher to 26 public resequencing data sets from nonmammalian vertebrates. These variant data sets are hosted publicly to enable future comparative population genomic analyses. With its extensibility and the availability of public data sets, snpArcher will contribute to a broader understanding of genetic variation across species by facilitating the rapid use and reuse of large genomic data sets.

Development and application of a high-temperature imaging system for in-situ scanning electron microscope

In-situ scanning electron microscope (SEM) is essential for investigating materials' properties. In this study, a custom-built in-situ heating system was developed to improve SEM imaging at elevated temperatures. A heater equipped with a double helical tungsten filament was specifically designed to achieve unprecedented high temperatures for heating materials. A bias-voltage control system was proposed to suppress thermal electrons during heating. Additionally, a high-temperature secondary-electron detector was developed and equipped with a variable visible-light filter to mitigate the impact of visible and infrared light at high temperatures. The heater and detector worked within a high vacuum environment with a pressure level below 1×10−3 Pa. Two in-situ heating experiments were conducted using the heating system to observe the melting and crystallizing processes of cobalt and the phase transformation of carbon steel. The results exhibited the remarkable capability of the heating system to image at temperatures as high as 1500 °C, offering a resolution of 40 nm. This heater is anticipated to advance materials characterization, providing comprehensive insights into their behavior at high temperatures and opening new avenues for developing material properties.

УНІВЕРСАЛЬНИЙ ТРИФАЗНИЙ ПАСИВНИЙ ФІЛЬТР ГАРМОНІК СТРУМУ МЕРЕЖІ

An analysis of well-known universal filters of current harmonics was carried out. A variant of the three-phase passive filter of network current harmonics is proposed, due to the change in its structure, the value of the voltage on the load is limited in operating modes close to idling. Mathematical modeling of such a system, which feeds a bridge rectifier with a capacitive filter and an active load with a power of 5 kW, was performed. The load characteristics and the depend-ence of the current harmonic coefficient on the change in the load power of the developed filter are given. Ref. 2, fig. 3. Keywords: current harmonic coefficient, THDI, passive filter, active filter of parallel type, hybrid filter, decentralized power supply system.

Robust adaptive smooth variable structure Kalman filter for spacecraft attitude estimation

This paper proposes a novel robust adaptive filter that combines smooth variable structure filter and extended Kalman filter for the spacecraft attitude estimation with model uncertainty originating from gyro drift, parameter error, and installation error. The proposed filter employs the extended Kalman filter based on quaternion and fuses an adaptive factor and smooth variable structure filter to improve robustness to the model uncertainty and noise. To improve the robustness of the extended Kalman filter, an adaptive factor that tunes the predicted covariance matrix is utilized to design the attitude estimation strategy. Moreover, to further decrease the impact of the suddenly rapid maneuvering and improve its robust effect of model uncertainty induced by dynamic error, gyro drift, and so on, a smooth variable structure estimation strategy founded on sliding mode theory is derived and utilized for the satellite attitude estimation. Thereby, a novel filtering algorithm is proposed by incorporating an adaptive factor and a smooth variable structure estimation strategy. Simulation results indicate that our proposed algorithm delivers exceptional robustness and achieves high precision and accuracy in satellite attitude estimation compared with the traditional extended Kalman filter.

Characterization of Clonal Hematopoietic of Indeterminate Potential (CHIP) Mutations in an Imid-Naïve Multiple Myeloma (MM) Autologous Stem Cell Transplant (ASCT) Population: First Results from a Pre-Transplant Time Point in a Prospective, Longitudinal Study

Background: Clonal Hematopoiesis of Indeterminate Potential (CHIP) is defined by the acquisition of ≥ 1 somatic mutations in the blood of healthy adults, but can also be detected at higher prevalence in patients with malignancies, particularly after DNA damaging therapy. The presence of CHIP mutations in MM confers a reduced overall survival (Mouhieddine, JCO 2020) but high quality, prospective evaluation of CHIP mutation evolution over the transplant sequence, including the impact of high-dose melphalan and immunomodulatory (IMiD)-based therapy, is largely under-studied. Serial assessment of CHIP over the transplant course has been reported from the coMMpass dataset, demonstrating a 4-fold increase in mutation prevalence from 5.8% at diagnosis to 25% after 3.1 years (Mouhieddine, Blood, 2021). In this data set, most patients were exposed to prior IMiD-containing at some point during therapy. Whether the survival benefit reported with IMiD-based maintenance therapy post-transplant is associated with CHIP mutation modulation is unclear. We are therefore investigating the longitudinal evolution of CHIP in a cohort of transplant-eligible, largely IMiD-naïve patients (pts) over the pre- and post-ASCT course in an ongoing study. Here, we present preliminary findings from the pre-transplant time-point after non-IMiD-containing induction but before high-dose melphalan and ASCT. Methods: The ongoing Princess Margaret Cancer Center ARCH 001 trial is a prospective, longitudinal study evaluating evolution of CHIP in a transplant-eligible MM population. Mutation testing is performed using the highly sensitive single-molecule molecular inversion probe (SmMIP) next-generation sequencing (NGS) technique (Abelson, Bioinformatics, 2022). After sequencing with a minimum sequencing depth of 4000x, the list of mutation calls produced by smMIP-tools is subject to various filters to reduce the likelihood of false positives. Synonymous mutations, as well as any variants falling within introns or splice regions are removed. The minor allele frequency of the variant (if available) is required to be above 0.1% so as to exclude mutations that are common SNPs. VAF frequency threshold of 1-30 % is set for calling somatic mutations, with a view to minimize false positives and germ-line mutations. Multiple time points for testing pertinent to therapy include: within 1 month pre-transplant (after induction and stem cell collection), 3 months post-transplant, and two subsequent samples 12 and 24 months post-sample 2. Here we report preliminary results of CHIP mutation testing in the first 66 pts at the pre-transplant time point. Results: Patient, disease and treatment characteristics for all pts and their stratification by the presence of CHIP mutations are outlined in Table 1. The total cohort is typical for a transplant-eligible population with median age 65 years, male predominance (M 59%/F 41%), 60% IgG subtype, 23% high-risk FISH cytogenetics. Most (90%) received a non-IMiD containing induction regimen CyBorD; only 6% received an IMiD pre-ASCT. CHIP mutations were identified in 28/66 pts, for a mutation prevalence rate of 43%; 6 patients (9%) carried ≥ 1 mutation. The median age at transplant as well as other baseline demographics did not differ between those with and without mutations (Table 1). Mutation profiles are shown in Figure 1, and are consistent with those described in the literature with the most commonly mutated genes being DNMT3a, TET2, ASXL1 and PPM1D, and the mutation prevalence rate highest for DNMT3a at 21%. 6 pts (9%) had ≥ 1 mutation (range 2-3) identified, with 3 of 6 involving the DNMT3a gene. Other genes involved in patients with multiple mutations were TET2 (n=3), ASXL1 (n=2), PPM1D (n=2), SRSF2 (n=1), SF3B1 (n=1). Mean allele frequency was 4%, ranging from 1-19. Conclusion: Our results using deep SmMIP sequencing show a mutation prevalence rate of 43% in a cohort of transplant-eligible, largely IMiD-naive MM pts studied after induction. These rates are higher than those generally described in the literature, which may relate to the high sensitivity of the assay used, variation in filtering between institutions, and the deliberate use of a relatively low VAF threshold with the intent to capture clinically significant variants for longitudinal tracking during the course of this ongoing study. Further studies during lenalidomide maintenance will be forthcoming.

Loss of Heterozygosity of Chromosome 9p and Progression in MPNs

Introduction Copy-neutral loss of heterozygosity (LOH) of chromosome 9p, concomitant with mutated JAK2, can occur in myeloproliferative neoplasms (MPNs), and may be the most common chromosomal aberration in patients with polycythemia vera (PV). The prevalence of LOH of 9p varies amongst the different MPNs and is highest in PV where it has been reported to be between 30-70%. The reported prevalence of LOH of 9p is 20-50% and 10-20% in patients with myelofibrosis (MF) and essential thrombocythemia (ET), respectively. A hallmark feature of MPNs is the tendency to progress to more aggressive disease phenotypes (i.e., PV/ET to MF to accelerated- or blast-phase MPN) through the acquisition or loss of cytogenetic and molecular clonal markers. Although loss of LOH of 9p likely contributes to progression in MPNs, its pathologic role is still incompletely defined. Methods We conducted a retrospective review of patients at a single-center, tertiary-care institution who were diagnosed with an MPN, either chronic, accelerated or blast-phase (MPN-AP/BP), from January 1 st, 2017 until July 1 st, 2023. All patients underwent a microarray-based chromosome analysis using the I Scan System with the Global Diversity Array-8 (GDA) v1.0 Array BeadChip. Mutational profiling was done using the NextGENe software (SoftGenetics LLC) and MiSeq Reporter, and variant annotation and filtration was performed using VarSeq (Golden Helix). Results Fifty-two patients with MF were identified. Twenty-eight patients (53.8%) were found to have LOH of 9p, 15 of whom had secondary MF (7 with preceding ET and 8 with preceding PV). Eight of 9 patients (88.9%) with PV-MF harbored LOH of 9p, vs. 6 of 13 (46.2%) with ET-MF. The median cell fraction affected was 70% (range, 5-95%) and the median JAK2 variant allele frequency (VAF) was 75% (range, 16-97%). Eleven of the 24 patients without LOH of 9p harbored JAK2 mutations, at a median VAF of 40%. Nine patients (32.2%) with LOH of 9p had abnormal cytogenetics by conventional karyotyping, compared to 8 (33.3%) without LOH of 9p. Eleven patients (39.3%) with LOH of 9p were MIPSS-70 v2 high or very high risk, compared to 10 (41.7%) patients without LOH of 9p. Nine patients (32.1%) with LOH of 9p were DIPSS-plus intermediate-2 or high-risk, compared with 9 (37.5%) patients without LOH of 9p. Twenty patients with MPN-AP/BP were identified, of whom 11 had MPN-AP and 9 had MPN-BP. Four patients (20%), all with MPN-BP, had LOH of 9p. Median JAK2 VAF in these patients was 50% (range, 38-80%), vs. 4% (range, 3-48%) in the 6 patients with JAK2 without LOH of 9p. Two of 19 patients (10.5%) with ET were found to have LOH of 9p, with a corresponding JAK2 VAF of 70% and 20%. Twelve of the 17 patients (70.6%) who did not have LOH of 9p had a JAK2 mutation, at a median VAF of 27% (range, 4-44%). One patient with LOH of 9p had a thrombotic event, vs. 4 of 17 patients (23.5%) without LOH of 9p. Three of 9 patients (33%) with PV were found to have a LOH of 9p, with a median corresponding JAK2 VAF of 61% (range, 55-81%). Median JAK2 VAF for the other 6 patients (all with a JAK2 mutation) was 34% (range, 26-46%). One patient with LOH of 9p had a thrombotic event vs. 3 of 6 patients (50%) without LOH of 9p. Discussion The highest prevalence of LOH of 9p in patients with an MPN was seen in those with MF (>50%), followed by PV, MPN-AP/BP and ET. These results are generally in line with those previously reported, though the prevalence in PV was lower than other studies (likely due to small sample size). The prevalence of LOH of 9p in ET-MF was more than four times higher than in ET, suggesting that LOH of 9p may be an acquired cytogenetic aberration involved in ET progression. LOH of 9p was seen in almost 90% of PV-MF vs. 33% of PV patients, further supporting that LOH of 9p may be implicated in MPN progression. Notably, LOH-9p was seen in far fewer patients with accelerated- or blast-phase disease. It is likely that clonal evolution of MPNs to MPN-AP/BP is driven more so by the acquisition of high-risk mutations (e.g., TP53, ASXL1, U2AF1) and less by changes such as LOH of 9p and increased JAK2 VAF. In summary, our data largely confirms previous reports regarding the prevalence of LOH of 9p in MPNs while suggesting a role for the gain or loss of LOH of 9p in the progression of these hematologic cancers.