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Despite significant advancements in rare genetic disease diagnostics, many patients with rare genetic disease remain without a molecular diagnosis. Novel tools and methods are needed to improve the detection of disease-associated variants and understand the genetic basis of many rare diseases. Long-read genome sequencing provides improved sequencing in highly repetitive, homologous, and low-complexity regions, and improved assessment of structural variation and complex genomic rearrangements compared to short-read genome sequencing. As such, it is a promising method to explore overlooked genetic variants in rare diseases with a high suspicion of a genetic basis. We therefore applied PacBio HiFi sequencing in a large multi-generational family presenting with autosomal dominant 46,XY differences of sexual development (DSD), for whom extensive molecular testing over multiple decades had failed to identify a molecular diagnosis. This revealed a rare SINE-VNTR-Alu retroelement insertion in intron 4 of NR5A1, a gene in which loss-of-function variants are an established cause of 46,XY DSD. The insertion segregated among affected family members and was associated with loss-of-expression of alleles in cis, demonstrating a functional impact on NR5A1. This case highlights the power of long-read genome sequencing to detect genomic variants that have previously been intractable to detection by standard short-read genomic testing.
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Transtorno 46,XY do Desenvolvimento Sexual , Retroelementos , Humanos , Mutação , Íntrons/genética , Retroelementos/genética , Transtorno 46,XY do Desenvolvimento Sexual/genética , Doenças Raras/genética , Desenvolvimento Sexual , Fator Esteroidogênico 1/genéticaRESUMO
The aim of this study was to evaluate the accuracy of nutrient intake assessment with the food group-based algorithm "Calculator of Inadequate Micronutrient Intake" (CIMI) in comparison to the established nutrition software NutriSurvey. Using Food Frequency Questionnaires and 24-h dietary recalls of 1010 women from two rural districts in Tanzania, 23 relevant typical Tanzanian food groups were identified and subsequently the dietary protocols assessed via CIMI algorithm were compared by bivariate correlations and Bland-Altman analysis with the results of the NutriSurvey software (reference) and were set in relation to blood biomarkers of 666 participants. CIMI and NutriSurvey calculations regarding macro- and micronutrient intakes were similar. The Bland-Altman analyses and correlation coefficients of energy (0.931), protein (0.898), iron (0.775) and zinc (0.838) confirm the agreement of both calculations. The food group based CIMI algorithm is a practical tool to identify the inadequacy of macro- and micronutrient intake at population level.
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Algoritmos , Dieta , Micronutrientes , Avaliação Nutricional , População Rural , Humanos , Feminino , Tanzânia , Adulto , Micronutrientes/administração & dosagem , Micronutrientes/sangue , Adulto Jovem , Pessoa de Meia-Idade , Ingestão de Energia , Inquéritos sobre Dietas , Inquéritos e Questionários , Nutrientes/análise , SoftwareRESUMO
PURPOSE: This study aimed to provide comprehensive diagnostic and candidate analyses in a pediatric rare disease cohort through the Genomic Answers for Kids program. METHODS: Extensive analyses of 960 families with suspected genetic disorders included short-read exome sequencing and short-read genome sequencing (srGS); PacBio HiFi long-read genome sequencing (HiFi-GS); variant calling for single nucleotide variants (SNV), structural variant (SV), and repeat variants; and machine-learning variant prioritization. Structured phenotypes, prioritized variants, and pedigrees were stored in PhenoTips database, with data sharing through controlled access the database of Genotypes and Phenotypes. RESULTS: Diagnostic rates ranged from 11% in patients with prior negative genetic testing to 34.5% in naive patients. Incorporating SVs from genome sequencing added up to 13% of new diagnoses in previously unsolved cases. HiFi-GS yielded increased discovery rate with >4-fold more rare coding SVs compared with srGS. Variants and genes of unknown significance remain the most common finding (58% of nondiagnostic cases). CONCLUSION: Computational prioritization is efficient for diagnostic SNVs. Thorough identification of non-SNVs remains challenging and is partly mitigated using HiFi-GS sequencing. Importantly, community research is supported by sharing real-time data to accelerate gene validation and by providing HiFi variant (SNV/SV) resources from >1000 human alleles to facilitate implementation of new sequencing platforms for rare disease diagnoses.
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Genômica , Doenças Raras , Criança , Genoma , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Linhagem , Doenças Raras/diagnóstico , Doenças Raras/genética , Análise de Sequência de DNARESUMO
OBJECTIVES: The aim of this study was to evaluate the potential mediating effects of depression and psychache (i.e., extreme mental pain) on the relationship between parental invalidation and nonsuicidal self-injury (NSSI) in young adults. METHOD: A sample of 2474 university students responded to previously validated measures of current NSSI, childhood parental invalidation, depression, and psychache. RESULTS: Using a parallel mediation model, path analysis using structural equation modeling demonstrated full mediation by depression and psychache of the link between parental invalidation and NSSI. CONCLUSIONS: Findings suggest that the association between invalidating childhood environments and NSSI has the potential to be mitigated by addressing issues of depression and psychache.
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Comportamento Autodestrutivo , Universidades , Criança , Depressão/epidemiologia , Humanos , Dor , Comportamento Autodestrutivo/epidemiologia , Estudantes , Adulto JovemRESUMO
Across two countries and two languages, this research examined the multidimensional associations of suicide behaviors (i.e., life-time attempts, life-time communication of intent to others, life-time self-harming, life-time suicide notes, and current suicide ideation) and empirically relevant psychological risk factors (i.e., different facets of mental pain, perceived burdensomeness, thwarted belongingness, and acquired capability), controlling for depressive symptoms. For the Portuguese sample, two underlying dimensions emerged: an ideation dimension and a behavioral dimension, and for the Canadian sample, three dimensions emerged: an ideation dimension and two behavioral dimensions that can be viewed as a splitting of the Portuguese second dimension. Results highlight possible cultural differences between the two countries and that suicide behaviors should be viewed as a multidimensional phenomenon not as a one-dimensional continuum.
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Relações Interpessoais , Ideação Suicida , Canadá , Humanos , Fatores de Risco , Inquéritos e QuestionáriosRESUMO
Across two countries and two languages, this research examined the multidimensional associations between suicidality (e.g., past ideation/attempts, communication of intent) and empirically important psychological risk factors (e.g., mental pain, perceived burdensomeness, thwarted belongingness). For samples of 228 Canadian and 331 Portuguese university undergraduates, four dimensions emerged in each sample with two of these, intrapersonal and interpersonal, demonstrating strong replicability across countries and languages. It was concluded that suicidality is a phenomenon that demonstrates some multidimensional similarities across cultures.
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Suicídio/psicologia , Adolescente , Adulto , Feminino , Humanos , Idioma , Masculino , Fatores de Risco , Adulto JovemRESUMO
OBJECTIVES: A multidimensional psychological pain model of suicide has been developed that includes three dimensions: affective, cognitive, and avoidance. In the present research, we evaluated the relationships between the three dimensions of psychological pain and suicidal ideation. METHOD: Two community samples from Portugal and the U.S. participated in the research. RESULTS: Hierarchical multiple regression analysis demonstrated that when controlling for the effects of depressive symptoms and psychache, the avoidance dimension, but not the cognitive or affective dimension of psychological pain, explained significant, and unique variance in suicidal ideation in each sample. CONCLUSION: Even when individuals perceive psychological pain, there may not be an elevated risk of suicide, provided that they do not consider suicide as a form of coping to decrease that pain.
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Aprendizagem da Esquiva , Comparação Transcultural , Dor/psicologia , Ideação Suicida , Adaptação Psicológica , Adolescente , Adulto , Idoso , Depressão/psicologia , Feminino , Humanos , Idioma , Masculino , Pessoa de Meia-Idade , Modelos Psicológicos , Portugal , Reprodutibilidade dos Testes , Suicídio/psicologia , Estados Unidos , Adulto JovemRESUMO
PurposeCurrent clinical genomics assays primarily utilize short-read sequencing (SRS), but SRS has limited ability to evaluate repetitive regions and structural variants. Long-read sequencing (LRS) has complementary strengths, and we aimed to determine whether LRS could offer a means to identify overlooked genetic variation in patients undiagnosed by SRS.MethodsWe performed low-coverage genome LRS to identify structural variants in a patient who presented with multiple neoplasia and cardiac myxomata, in whom the results of targeted clinical testing and genome SRS were negative.ResultsThis LRS approach yielded 6,971 deletions and 6,821 insertions > 50 bp. Filtering for variants that are absent in an unrelated control and overlap a disease gene coding exon identified three deletions and three insertions. One of these, a heterozygous 2,184 bp deletion, overlaps the first coding exon of PRKAR1A, which is implicated in autosomal dominant Carney complex. RNA sequencing demonstrated decreased PRKAR1A expression. The deletion was classified as pathogenic based on guidelines for interpretation of sequence variants.ConclusionThis first successful application of genome LRS to identify a pathogenic variant in a patient suggests that LRS has significant potential for the identification of disease-causing structural variation. Larger studies will ultimately be required to evaluate the potential clinical utility of LRS.
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Estudos de Associação Genética , Doenças Genéticas Inatas/diagnóstico , Doenças Genéticas Inatas/genética , Predisposição Genética para Doença , Variação Genética , Genoma Humano , Genômica , Análise de Sequência de DNA , Criança , Subunidade RIalfa da Proteína Quinase Dependente de AMP Cíclico/genética , Ecocardiografia , Genômica/métodos , Humanos , Masculino , Fenótipo , Análise de Sequência de DNA/métodos , Deleção de SequênciaRESUMO
BACKGROUND: Iron ore (taconite) mining and processing are an important industry in northern Minnesota and western Michigan. Concerns around exposures have centered largely on exposure to non-asbestiform amphibole elongate mineral particles (EMPs) found in the eastern portion of the Minnesota iron range. METHODS: A cross sectional survey was undertaken of current and former taconite workers and spouses along with a detailed exposure assessment. Participants provided an occupational history and had a chest radiograph performed. RESULTS: A total of 1188 workers participated. Potential exposures to non-amphibole EMPs were evident across multiple jobs in all active mines. Pleural abnormalities were found in 16.8% of workers. There was an association of pleural abnormalities with cumulative EMP exposure that was not specific to the eastern portion of the range. CONCLUSION: There was evidence of a mild to moderate increase in pleural abnormalities in this population of miners, associated with geographically non-specific cumulative EMP exposure.
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Ferro/efeitos adversos , Doenças Profissionais/induzido quimicamente , Doenças Profissionais/epidemiologia , Exposição Ocupacional/efeitos adversos , Doenças Pleurais/induzido quimicamente , Doenças Pleurais/epidemiologia , Silicatos/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Monitoramento Ambiental/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mineração , Minnesota/epidemiologia , Doenças Profissionais/diagnóstico por imagem , Doenças Pleurais/diagnóstico por imagem , Análise de Regressão , Fatores de RiscoRESUMO
OBJECTIVES: Using a 4-year follow-up design, this research investigated Shneidman's model of psychache (i.e., intense mental pain/anguish) as the cause of suicide. Operationalizing suicidal manifestations using suicide ideation, we evaluated Shneidman's assertion that psychache is the prominent predictor of suicide ideation and that other suicide-related psychological variables associate with suicide ideation only through psychache. METHOD: Eighty-two undergraduates at elevated suicide risk were assessed at baseline and follow-up with measures of suicide ideation and three psychological predictors: depression, hopelessness, and psychache. RESULTS: At baseline, only psychache and neither depression nor hopelessness contributed significant, unique information to statistically predicting suicide ideation. For 4-year change in suicide ideation, only psychache and neither depression nor hopelessness provided significant, unique information. CONCLUSIONS: Results provided partial support for Shneidman's contention of the importance of psychache for suicidal behavior and that other psychological factors are only important to suicide insofar as they relate through psychache.
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Depressão/psicologia , Transtorno Depressivo/psicologia , Estresse Psicológico/psicologia , Estudantes/psicologia , Ideação Suicida , Adolescente , Adulto , Feminino , Humanos , Estudos Longitudinais , Masculino , Modelos Psicológicos , Dor/psicologia , Risco , Universidades , Adulto JovemRESUMO
OBJECTIVES: An excess of mesothelioma has been observed in iron ore miners in Northeastern Minnesota. Mining and processing of taconite iron ore generate exposures that include elongate mineral particles (EMPs) of amphibole and non-amphibole origin. We conducted a nested case-control study of mesothelioma in a cohort of 68,737 iron ore miners (haematite and taconite ore miners) to evaluate the association between mesothelioma, employment and EMP exposures from taconite mining. METHODS: Mesothelioma cases (N=80) were identified through the Minnesota Cancer Surveillance System (MCSS) and death certificates. Four controls of similar age were selected for each case with 315 controls ultimately eligible for inclusion. Mesothelioma risk was evaluated by estimating rate ratios and 95% CIs with conditional logistic regression in relation to duration of taconite industry employment and cumulative EMP exposure [(EMP/cc)×years], defined by the National Institute for Occupational Safety and Health (NIOSH) 7400 method. Models were adjusted for employment in haematite mining and potential exposure to commercial asbestos products used in the industry. RESULTS: All mesothelioma cases were male and 57 of the cases had work experience in the taconite industry. Mesothelioma was associated with the number of years employed in the taconite industry (RR=1.03, 95% CI 1.00 to 1.06) and cumulative EMP exposure (RR=1.10, 95% CI 0.97 to -1.24). No association was observed with employment in haematite mining. CONCLUSIONS: These results support an association between mesothelioma and employment duration and possibly EMP exposure in taconite mining and processing. The type of EMP was not determined. The potential role of commercial asbestos cannot be entirely ruled out.
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Ferro/efeitos adversos , Neoplasias Pulmonares/etiologia , Mesotelioma/etiologia , Mineração , Doenças Profissionais/etiologia , Exposição Ocupacional/efeitos adversos , Material Particulado/efeitos adversos , Silicatos/efeitos adversos , Adulto , Poluentes Ocupacionais do Ar/efeitos adversos , Estudos de Casos e Controles , Emprego , Feminino , Compostos Férricos/efeitos adversos , Humanos , Modelos Logísticos , Neoplasias Pulmonares/mortalidade , Masculino , Mesotelioma/mortalidade , Minerais , Minnesota/epidemiologia , Doenças Profissionais/mortalidade , Fatores de Risco , TrabalhoRESUMO
Van Hooft and Born (Journal of Applied Psychology 97:301-316, 2012) presented data challenging both the correctness of a congruence model of faking on personality test items and the relative merit (i.e., effect size) of response latencies for identifying fakers. We suggest that their analysis of response times was suboptimal, and that it followed neither from a congruence model of faking nor from published protocols on appropriately filtering the noise in personality test item answering times. Using new data and following recommended analytic procedures, we confirmed the relative utility of response times for identifying personality test fakers, and our obtained results, again, reinforce a congruence model of faking.
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Enganação , Detecção de Mentiras/psicologia , Inventário de Personalidade , Testes de Personalidade , Tempo de Reação/fisiologia , Adolescente , Interpretação Estatística de Dados , Feminino , Humanos , Masculino , Modelos Psicológicos , Personalidade , Adulto JovemRESUMO
Edible insects are attracting increased interest worldwide, because they are arguably more sustainable than more established animal foods. Apart from being rich in protein and minerals, they can also form vitamin D3 after treatment with UVB light (290-315 nm). However, only limited research, which has almost exclusively been conducted on living insects, reared under UVB lamps, has been done in this regard. As research on mushrooms has shown, that vitamin D formation is much more effective and less time consuming, when a previously sliced or ground product is treated with UVB light, it would likely be more practical to treat powdered insects with UVB light, rather than rearing them under UVB lamps. Therefore, the aim of this work was to confirm the presence of vitamin D3 in powdered UVB-treated yellow mealworms (Tenebrio molitor), migratory locusts (Locusta migratoria) and two-spotted crickets (Gryllus bimaculatus) as well as to subsequently quantify potential vitamin D content. Samples were analyzed via HPLC, and presence of vitamin D3 was verified via standard addition and spectrum analysis. UVB-treated migratory locusts and two-spotted crickets did not contain quantifiable amounts of vitamin D3. However, UVB-treated mealworms showed substantial amounts of vitamin D3 (8.95-18.24 µg/g dry matter). Thus, the UVB-treatment of powdered mealworm is an effective approach via which to enhance their vitamin D3 content and even modest serving sizes can supply the recommended daily intake of vitamin D.
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Insetos Comestíveis , Tenebrio , Animais , Vitamina D , Vitaminas , Colecalciferol/análise , InsetosRESUMO
Comprehending the mechanism behind human diseases with an established heritable component represents the forefront of personalized medicine. Nevertheless, numerous medically important genes are inaccurately represented in short-read sequencing data analysis due to their complexity and repetitiveness or the so-called 'dark regions' of the human genome. The advent of PacBio as a long-read platform has provided new insights, yet HiFi whole-genome sequencing (WGS) cost remains frequently prohibitive. We introduce a targeted sequencing and analysis framework, Twist Alliance Dark Genes Panel (TADGP), designed to offer phased variants across 389 medically important yet complex autosomal genes. We highlight TADGP accuracy across eleven control samples and compare it to WGS. This demonstrates that TADGP achieves variant calling accuracy comparable to HiFi-WGS data, but at a fraction of the cost. Thus, enabling scalability and broad applicability for studying rare diseases or complementing previously sequenced samples to gain insights into these complex genes. TADGP revealed several candidate variants across all cases and provided insight into LPA diversity when tested on samples from rare disease and cardiovascular disease cohorts. In both cohorts, we identified novel variants affecting individual disease-associated genes (e.g., IKZF1, KCNE1). Nevertheless, the annotation of the variants across these 389 medically important genes remains challenging due to their underrepresentation in ClinVar and gnomAD. Consequently, we also offer an annotation resource to enhance the evaluation and prioritization of these variants. Overall, we can demonstrate that TADGP offers a cost-efficient and scalable approach to routinely assess the dark regions of the human genome with clinical relevance.
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Using five complementary short- and long-read sequencing technologies, we phased and assembled >95% of each diploid human genome in a four-generation, 28-member family (CEPH 1463) allowing us to systematically assess de novo mutations (DNMs) and recombination. From this family, we estimate an average of 192 DNMs per generation, including 75.5 de novo single-nucleotide variants (SNVs), 7.4 non-tandem repeat indels, 79.6 de novo indels or structural variants (SVs) originating from tandem repeats, 7.7 centromeric de novo SVs and SNVs, and 12.4 de novo Y chromosome events per generation. STRs and VNTRs are the most mutable with 32 loci exhibiting recurrent mutation through the generations. We accurately assemble 288 centromeres and six Y chromosomes across the generations, documenting de novo SVs, and demonstrate that the DNM rate varies by an order of magnitude depending on repeat content, length, and sequence identity. We show a strong paternal bias (75-81%) for all forms of germline DNM, yet we estimate that 17% of de novo SNVs are postzygotic in origin with no paternal bias. We place all this variation in the context of a high-resolution recombination map (â¼3.5 kbp breakpoint resolution). We observe a strong maternal recombination bias (1.36 maternal:paternal ratio) with a consistent reduction in the number of crossovers with increasing paternal (r=0.85) and maternal (r=0.65) age. However, we observe no correlation between meiotic crossover locations and de novo SVs, arguing against non-allelic homologous recombination as a predominant mechanism. The use of multiple orthogonal technologies, near-telomere-to-telomere phased genome assemblies, and a multi-generation family to assess transmission has created the most comprehensive, publicly available "truth set" of all classes of genomic variants. The resource can be used to test and benchmark new algorithms and technologies to understand the most fundamental processes underlying human genetic variation.
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Cutaneous T-cell lymphomas are a class of non-Hodgkin lymphomas characterized by the infiltration of malignant T cells into the skin. Their precise pathogenesis remains incompletely understood, but persistent and specific antigen stimulation of skin-homing CD4+ memory T cells by external or internal factors, combined with an inflammatory cytokine-rich tissue microenvironment, may be critical in the development of cutaneous T-cell lymphomas. We present herein a case of primary cutaneous T-cell lymphoma arising in two surgical scars that developed 6 months post-operatively and were successfully treated with external beam radiotherapy. This case highlights the notion that primary cutaneous T-cell lymphoma can develop locally at the site of injury/foreign body within a relatively short time post trauma/surgery. This work contributes to the literature of cutaneous T-cell lymphomas arising after a trauma, surgery, or a foreign body.
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Purpose: Patients with early stage breast cancer (ESBC) are conventionally treated with breast-conserving surgery (BCS) followed by whole-breast external beam radiation therapy (EBRT). The emergence of targeted intraoperative radiation therapy (TARGIT) with Intrabeam has been used as a therapeutic alternative for patients with risk-adapted ESBC. Here we present our radiation therapy toxicities (RTT), postoperative complications (PC), and short-term outcomes of the prospective phase II trial at the McGill University Health Center. Methods and Materials: Patients aged ≥50 years with biopsy-proven hormone receptor-positive, grade 1 or 2, invasive ductal carcinoma of the breast, cT1N0, were eligible for the study. Enrolled patients underwent BCS followed by immediate TARGIT of 20 Gy in 1 fraction. Upon final pathology, patients with low-risk breast cancer (LRBC) received no further EBRT, and those with high-risk breast cancer (HRBC) received further 15 to 16 fractions of whole breast EBRT. HRBC criteria included pathologic tumor size >2 cm, grade 3, positive lympho-vascular invasion, multifocal disease, close margins (<2 mm), or positive nodal disease. Results: A total of 61 patients with ESBC were enrolled in the study; upon final pathology, 40 (65.6%) had LRBC, and 21 (34.4%) had HRBC. The median follow-up was 3.9 years. The most common HRBC criteria were close margins in 66.6% (n = 14) and lymphovascular invasion in 28.6% (n = 6). No grade 4 RTT were observed in either group. The most common PC were seroma and cellulitis for both groups. The rate of locoregional recurrence was 0% in both groups. The overall survival in LRBC was 97.5% and in HRBC 95.2% with no significant differences. Deaths were nonbreast cancer related. Conclusions: In patients with ESBC undergoing BCS, the use of TARGIT shows low rates of RTT and PC complications. Moreover, our short-term outcomes show no significant difference at 3.9 years median follow-up for locoregional recurrence or overall survival between groups of patients receiving TARGIT alone or TARGIT followed by EBRT. Of all patients, 34.4% required further EBRT, most commonly due to close margins.
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BACKGROUND: Long-read sequencing (LRS) techniques have been very successful in identifying structural variants (SVs). However, the high error rate of LRS made the detection of small variants (substitutions and short indels < 20 bp) more challenging. The introduction of PacBio HiFi sequencing makes LRS also suited for detecting small variation. Here we evaluate the ability of HiFi reads to detect de novo mutations (DNMs) of all types, which are technically challenging variant types and a major cause of sporadic, severe, early-onset disease. METHODS: We sequenced the genomes of eight parent-child trios using high coverage PacBio HiFi LRS (~ 30-fold coverage) and Illumina short-read sequencing (SRS) (~ 50-fold coverage). De novo substitutions, small indels, short tandem repeats (STRs) and SVs were called in both datasets and compared to each other to assess the accuracy of HiFi LRS. In addition, we determined the parent-of-origin of the small DNMs using phasing. RESULTS: We identified a total of 672 and 859 de novo substitutions/indels, 28 and 126 de novo STRs, and 24 and 1 de novo SVs in LRS and SRS respectively. For the small variants, there was a 92 and 85% concordance between the platforms. For the STRs and SVs, the concordance was 3.6 and 0.8%, and 4 and 100% respectively. We successfully validated 27/54 LRS-unique small variants, of which 11 (41%) were confirmed as true de novo events. For the SRS-unique small variants, we validated 42/133 DNMs and 8 (19%) were confirmed as true de novo event. Validation of 18 LRS-unique de novo STR calls confirmed none of the repeat expansions as true DNM. Confirmation of the 23 LRS-unique SVs was possible for 19 candidate SVs of which 10 (52.6%) were true de novo events. Furthermore, we were able to assign 96% of DNMs to their parental allele with LRS data, as opposed to just 20% with SRS data. CONCLUSIONS: HiFi LRS can now produce the most comprehensive variant dataset obtainable by a single technology in a single laboratory, allowing accurate calling of substitutions, indels, STRs and SVs. The accuracy even allows sensitive calling of DNMs on all variant levels, and also allows for phasing, which helps to distinguish true positive from false positive DNMs.
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Sequenciamento de Nucleotídeos em Larga Escala , Mutação INDEL , Humanos , Alelos , Repetições de MicrossatélitesRESUMO
Application of Fe-zeolites for urea-SCR of NO(x) in diesel engine is limited by catalyst deactivation with hydrocarbons (HCs). In this work, a series of Fe-zeolite catalysts (Fe-MOR, Fe-ZSM-5, and Fe-BEA) was prepared by ion exchange method, and their catalytic activity with or without propene for selective catalytic reduction of NO(x) with ammonia (NH(3)-SCR) was investigated. Results showed that these Fe-zeolites were relatively active without propene in the test temperature range (150-550 °C); however, all of the catalytic activity was suppressed in the presence of propene. Fe-MOR kept relatively higher activity with almost 80% NO(x) conversion even after propene coking at 350 °C, and 38% for Fe-BEA and 24% for Fe-ZSM-5 at 350 °C, respectively. It was found that the pore structures of Fe-zeolite catalysts were one of the main factors for coke formation. As compared to ZSM-5 and HBEA, MOR zeolite has a one-dimensional structure for propene diffusion, relatively lower acidity, and is not susceptible to deactivation. Nitrogenated organic compounds (e.g., isocyanate) were observed on the Fe-zeolite catalyst surface. The site blockage was mainly on Fe(3+) sites, on which NO was activated and oxidized. Furthermore, a novel fully formulated Fe-BEA monolith catalyst coating modified with MOR was designed and tested, the deactivation due to propene poisoning was clearly reduced, and the NO(x) conversion reached 90% after 700 ppm C(3)H(6) exposure at 500 °C.
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Poluição do Ar/prevenção & controle , Alcenos/química , Ferro/química , Óxidos de Nitrogênio/química , Emissões de Veículos/prevenção & controle , Zeolitas/química , Amônia/química , Catálise , Troca Iônica , Oxirredução , Temperatura , Emissões de Veículos/análiseRESUMO
PURPOSE: Oral mucositis (OM) is known to be a significant complication of chemotherapy preceding haematopoietic cell transplantation (HCT). Antioxidants (AOX) scavenge free radicals, which play a major role in the initiation of OM and may reduce the OM risk. STUDY DESIGN: The primary objective of this prospective study was to investigate the association between the incidence and severity of OM (WHO oral toxicity scale) and the AOX status in buccal mucosa cells (BMC) and plasma. The α-tocopherol, ascorbic acid and ß-carotene concentrations in BMC and plasma were assessed at admission in 70 patients with a median age of 58 years before undergoing allogeneic HCT. RESULTS: Severe OM (III-IV), ulcerative OM (II-IV) and no or mild OM (0-I) were documented in 14 (20.0%), 32 (45.7%) and 38 (54.3%) patients, respectively. We observed no significant differences in baseline AOX concentrations in plasma or BMC among the OM groups. However, between patients with at least one plasma AOX beneath the normal range (39/70) and those with all plasma AOX in the normal range (31/70), we noted a trend towards longer duration of parenteral nutrition (PN) during the study period (10 vs. 8 days; p = 0.066). CONCLUSIONS: No single AOX, either in plasma or BMC (α-tocopherol, ascorbic acid and ß-carotene), revealed predictive value for the incidence or severity of OM. However, patients with an overall good plasma AOX status tended to require less PN, a common clinical marker for OM, which may be more relevant than any one AOX at reducing the risk of OM.