Forward and inverse problems in the mechanics of soft filaments

Soft slender structures are ubiquitous in natural and artificial systems, in active and passive settings and across scales, from polymers and flagella, to snakes and space tethers. In this paper, we demonstrate the use of a simple and practical numerical implementation based on the Cosserat rod model to simulate the dynamics of filaments that can bend, twist, stretch and shear while interacting with complex environments via muscular activity, surface contact, friction and hydrodynamics. We validate our simulations by solving a number of forward problems involving the mechanics of passive filaments and comparing them with known analytical results, and extend them to study instabilities in stretched and twisted filaments that form solenoidal and plectonemic structures. We then study active filaments such as snakes and other slender organisms by solving inverse problems to identify optimal gaits for limbless locomotion on solid surfaces and in bulk liquids.

Contrast-enhanced ultrasound findings in soft-tissue lesions: preliminary results

OBJECTIVES

There is currently no widely available, minimally invasive first-level examination that allows physicians to identify soft-tissue lesions that are likely to be malignant. The aim of this pilot study was to explore the potential suitability of dynamic contrast-enhanced ultrasound (DCE-US) for this purpose.

MATERIALS AND METHODS

23 patients were referred to the Veneto Oncological Institute for work-up of superficial soft-tissue lesions. Fourteen lesions were examined with CEUS and enhancement kinetics was analyzed. Subsequently, all lesions were surgically removed and subjected to histological analysis.

RESULTS

The 14 lesions included in the study were histologically classified as malignant (n = 7) or benign (n = 7, including 3 schwannomas). A statistically significant difference between benign and malignant lesions was found in terms of mean times to peak enhancement intensity (p = 0.03) but not mean filling times (FT). When schwannomas were analyzed as a separate group, their mean FT was found to be significantly different from that of the other benign lesions (p = 0.001) and from that of the group comprising other benign lesions as well as malignant lesions (p < 0.005).

CONCLUSIONS

CEUS with analysis of contrast-enhancement kinetics is a relatively low-cost, minimally invasive imaging technique, which appears to be a potentially effective first-level method for identifying suspicious soft-tissue masses.

[Extracellular molecules controlling the contraction of airway smooth muscle and their potential contribution to bronchial hyperresponsiveness]

INTRODUCTION

A significant portion of symptoms in some lung diseases results from an excessive constriction of airways due to the contraction of smooth muscle and bronchial hyperresponsiveness. A better understanding of the extracellular molecules that control smooth muscle contractility is necessary to identify the underlying causes of the problem.

STATE OF KNOWLEDGE

Almost a hundred molecules, some of which newly identified, influence the contractility of airway smooth muscle. While some molecules activate the contraction, others activate the relaxation, thus acting directly as bronchoconstrictors and bronchodilators, respectively. Other molecules do not affect contraction directly but rather influence it indirectly by modifying the effect of bronchoconstrictors and bronchodilators. These are called bronchomodulators. Some of these bronchomodulators increase the contractile effect of bronchoconstrictors and could thus contribute to bronchial hyperresponsiveness.

PROSPECTS

Considering the high number of molecules potentially involved, as well as the level of functional overlap between some of them, identifying the extracellular molecules responsible for excessive airway constriction in a patient is a major contemporary challenge.

Genotyping Analysis by RAD-Seq Reads Is Useful to Assess the Genetic Identity and Relationships of Breeding Lines in Lavender Species Aimed at Managing Plant Variety Protection

Lavender species are widely distributed in their wild forms around the Mediterranean Basin and they are also cultivated worldwide as improved and registered clonal varieties. The economic interest of the species belonging to the Lavandula genus is determined by their use as ornamental plants and important source of essential oils that are destinated to the production of cosmetics, pharmaceuticals and foodstuffs. Because of the increasing number of cases of illegal commercialization of selected varieties, the protection of plant breeders’ rights has become of main relevance for the recognition of breeding companies’ royalties. With this aim, genomic tools based on molecular markers have been demonstrated to be very reliable and transferable among laboratories, and also much more informative than morphological descriptors. With the rising of the next-generation sequencing (NGS) technologies, several genotyping-by-sequencing approaches are now available. This study deals with a deep characterization of 15 varietal clones, belonging to two distinct Lavandula species, by means of restriction-site associated DNA sequencing (RAD-Seq). We demonstrated that this technology screens single nucleotide variants that enable to assess the genetic identity of individual accessions, to reconstruct genetic relationships among related breeding lines, to group them into genetically distinguishable main subclusters, and to assign their molecular lineages to distinct ancestors. Moreover, a number of polymorphic sites were identified within genes putatively involved in biosynthetic pathways related to both tissue pigmentation and terpene production, useful for breeding and/or protecting newly registered varieties. Overall, the results highlighted the presence of pure ancestries and interspecific hybrids for the analyzed Lavandula species, and demonstrated that RAD-Seq analysis is very informative and highly reliable for characterizing Lavandula clones and managing plant variety protection.

Quantitative flow analysis of swimming dynamics with coherent Lagrangian vortices

Undulatory swimmers flex their bodies to displace water, and in turn, the flow feeds back into the dynamics of the swimmer. At moderate Reynolds number, the resulting flow structures are characterized by unsteady separation and alternating vortices in the wake. We use the flow field from simulations of a two-dimensional, incompressible viscous flow of an undulatory, self-propelled swimmer and detect the coherent Lagrangian vortices in the wake to dissect the driving momentum transfer mechanisms. The detected material vortex boundary encloses a Lagrangian control volume that serves to track back the vortex fluid and record its circulation and momentum history. We consider two swimming modes: the C-start escape and steady anguilliform swimming. The backward advection of the coherent Lagrangian vortices elucidates the geometry of the vorticity field and allows for monitoring the gain and decay of circulation and momentum transfer in the flow field. For steady swimming, momentum oscillations of the fish can largely be attributed to the momentum exchange with the vortex fluid. For the C-start, an additionally defined jet fluid region turns out to balance the high momentum change of the fish during the rapid start.

Developing and Testing Molecular Markers in Cannabis sativa (Hemp) for Their Use in Variety and Dioecy Assessments

Cannabis sativa (2n = 2x = 20) is a popular species belonging to the Cannabaceae family. Despite its use for medical, recreational, and industrial purposes as well as its long history, the genetic research on this species is in its infancy due to the legal implications and the prohibition campaigns. The recent legalization of Cannabis in many countries along with the use of genomics boosted the approaches aimed at marker-assisted selection, germplasm management, genetic discrimination, and authentication of cultivars. Nonetheless, the exploitation of molecular markers for the development of commercial varieties through marker-assisted breeding schemes is still rare. The present study aimed to develop an informative panel of simple sequence repeat markers to be used for the genotyping of high breeding value C. sativa lines. Starting from 41 nuclear SSR designated by in silico analyses, we selected 20 highly polymorphic and discriminant loci that were tested in 104 individuals belonging to 11 distinct hemp varieties. The selected markers were successful in accessing homozygosity, genetic uniformity, and genetic variation within and among varieties. Population structure analysis identified eight genetic groups, clustering individuals based on sexual behaviors (dioecious and monoecious) and geographical origins. Overall, this study provides important tools for the genetic characterization, authentication, conservation of biodiversity, genetic improvement and traceability of this increasingly important plant species.

AVALIAÇÃO DO NÍVEL DE RUÍDO, ITENS DE SEGURANÇA E ERGONOMIA EM TRATORES AGRÍCOLAS

O ruído das máquinas agrícolas, com o passar do tempo, pode provocar problemas auditivos nos operadores. De acordo com as normas regulamentadoras do Ministério do Trabalho e Emprego (NR 15), a exposição diária máxima permitida, durante uma jornada de trabalho de 8 horas, é de 85 decibels (dB (A)). Baseado neste contexto, este trabalho teve como objetivo avaliar os níveis de ruído emitidos por 12 tratores agrícolas de diferentes modelos e potências, bem como avaliar a existência de itens de ergonomia e segurança destes, comparando os resultados com as normas vigentes no Brasil. Os itens ergonômicos e de segurança dos tratores foram vistoriados e listados quanto sua conformidade ou não. Observou-se que para tratores sem cabina fechada o nível de ruído próximo (10 cm) ao ouvido dos operadores foi superior ao nível permitido pela Norma Regulamentadora (NR15), sendo necessário o uso de protetor auricular por parte dos operadores. Conclui-se ainda que a diminuição dos ruídos junto ao ouvido do operador é proporcionada pela presença de cabinas fechadas originais de fábrica. Ademais, verificou-se que os tratores mais novos atendem melhor aos requisitos de segurança e ergonomia.

First genomic insights into the Mandevilla genus

Mandevilla (Apocynaceae) is a greatly appreciated genus in the world ornamental market. In this study, we attempted to address the poor genetic knowledge and the huge taxonomic gaps existing in this genus by analyzing a collection of 55 accessions. After cytometrically determining the triploid genome size (1,512.64 Mb) of a reference sample (variety "Mandevilla 2001"), the plastidial genome (cpDNA, 0.18 Mb) and a draft of the nuclear genome (nuDNA, 207 Mb) were assembled. While cpDNA was effective in reconstructing the phylogenesis of the Apocynaceae family based on a DNA superbarcoding approach, the nuDNA assembly length was found to be only 41% of the haploid genome size (506 Mb, predicted based on the K-mer frequency distribution). Its annotation enabled the prediction of 37,811 amino acid sequences, of which 10,562 resulted full length proteins. Among them, we identified nine proteins whose orthologs (in Catharanthus roseus) are involved in the biosynthesis of monoterpene indole alkaloids (MIAs), including catharanthine, tabersonine, and vincadifformine. The nuclear genome draft was also useful to develop a highly informative (average polymorphism information content, PIC = 0.62) set of 23 simple sequence repeat (SSR) markers that was validated on the Mandevilla collection. These results were integrated with cytometric measurements, nuclear ITS1 haplotyping and chloroplast DNA barcoding analyses to assess the origin, divergence and relationships existing among the 55 accessions object of the study. As expected, based on the scarce information available in the literature, the scenario was extremely intricate. A reasonable hypothesis is that most of the accessions represent interspecific hybrids sharing the same species as maternal parent (i.e., Mandevilla sanderi).

Exploring depression in people with schizophrenia spectrum disorders: A cross-sectional analysis of the clinical relationship with Positive and Negative Syndrome Scale dimensions

OBJECTIVE

Evidence on the relationship between depression and clinical dimensions of schizophrenia remains limited. This cross-sectional study investigated the association between depression and Positive and Negative Syndrome Scale (PANSS) dimensions in people with schizophrenia spectrum disorders.

METHODS

Trained assessors administered the PANSS to measure symptoms of schizophrenia and the Calgary Depression Scale for Schizophrenia to measure depression. The association of depression with overall PANSS score and related dimensions was investigated in multiple logistic regression analyses.

RESULTS

We included 231 inpatients with schizophrenia spectrum disorders (mean age: 42.4 (SD: 12.9) years; men: 58.9%; mean overall PANSS score: 82.5 (SD: 20.1); drug-free or naïve: 39.3%), including 78 (33.8%) with clinically significant depressive symptoms. Depression was associated with higher overall (regression coefficient, SE: 0.029, 0.008; p < 0.001) and general psychopathology (regression coefficient, SE: 0.118, 0.023; p < 0.001) PANSS scores. We found an inverse relationship between depression and positive symptoms (regression coefficient, SE: -0.088, 0.028; p = 0.002). No association between depression and negative symptoms was found.

CONCLUSION

Despite some limitations, our study shows that people affected by schizophrenia spectrum disorders with depression are likely to show more overall and general psychopathology symptoms but lower positive symptoms. Additional studies are needed to explore the generalizability of our findings.

Complete blood count-based inflammation indexes and symptom severity in people with schizophrenia spectrum disorders: An analysis based on structural equation modelling

INTRODUCTION

Schizophrenia spectrum disorders (SSDs) are associated with immune-inflammatory activation. Recently, complete blood count (CBC)-based inflammation indexes such as the neutrophil-to-lymphocyte ratio (NLR), the monocyte-to-lymphocyte ratio (MLR), and the platelet-to-lymphocyte ratio (PLR) have emerged as reproducible and cost-effective inflammation markers in mental disorders. In this study, we aimed at investigating the relationship of NLR, MLR, and PLR with symptom severity in people with SSDs, testing interactions with relevant clinical variables.

METHODS

We included inpatients with SSDs aged 18-65 consecutively hospitalized from May 2020 to March 2024. Socio-demographic and clinical data were recorded. CBC-based ratios were estimated from routinely collected blood samples. Structural equation modelling (SEM) was performed to test relationships involving symptom severity constructs and CBC-based ratios, accounting for substance use disorder, antipsychotic treatment, and obesity.

RESULTS

Two hundred sixty-six participants met inclusion criteria. The SEM analysis uncovered a significant relationship of MLR with positive (coeff.: 0.19, p=0.048) and negative (coeff.: 0.27, p=0.004) symptoms, also showing a significant link of substance use disorder and antipsychotic treatment with symptom severity as well as of antipsychotic treatment with obesity.

CONCLUSIONS

Notwithstanding the cross-sectional design and the somewhat limited sample representativeness, this study showed a significant relationship between the MLR - but not the NLR or the PLR - and the severity of both positive and negative symptoms, testing at the same time the interactions with other clinical variables. Considering the insufficiency and inconsistency of data in this field, further research is needed to validate our findings and elucidate the underlying mechanisms driving the observed relationships between the MLR and SSD symptoms.

Prevalence and correlates of manic/hypomanic and depressive predominant polarity in bipolar disorder: systematic review and meta-analysis

BACKGROUND

Identification of the predominant polarity, i.e. hypomanic/manic (mPP) or depressive predominant polarity (dPP), might help clinicians to improve personalised management of bipolar disorder.

AIMS

We performed a systematic review and meta-analysis to estimate prevalence and correlates of mPP and dPP in bipolar disorder.

METHOD

The protocol was registered in the Open Science Framework Registries (https://doi.org/10.17605/OSF.IO/8S2HU). We searched main electronic databases up to December 2023 and performed random-effects meta-analyses of weighted prevalence of mPP and dPP. Odds ratios and weighted mean differences (WMDs) were used for relevant correlates.

RESULTS

We included 28 studies, providing information on rates and/or correlates of mPP and dPP. We estimated similar rates of mPP (weighted prevalence = 30.0%, 95% CI: 23.1 to 37.4%) and dPP (weighted prevalence = 28.5%, 95% CI: 23.7 to 33.7%) in bipolar disorder. Younger age (WMD = -3.19, 95% CI: -5.30 to -1.08 years), male gender (odds ratio = 1.39, 95% CI: 1.10 to 1.76), bipolar-I disorder (odds ratio = 4.82, 95% CI: 2.27 to 10.24), psychotic features (odds ratio = 1.56, 95% CI: 1.01 to 2.41), earlier onset (WMD = -1.57, 95% CI: -2.88 to -0.26 years) and manic onset (odds ratio = 13.54, 95% CI: 5.83 to 31.46) were associated with mPP (P < 0.05). Depressive onset (odds ratio = 12.09, 95% CI: 6.38 to 22.90), number of mood episodes (WMD = 0.99, 95% CI: 0.28 to 1.70 episodes), history of suicide attempts (odds ratio = 2.09, 95% CI: 1.49 to 2.93) and being in a relationship (odds ratio = 1.98, 95% CI: 1.22 to 3.22) were associated with dPP (P < 0.05). No differences were estimated for other variables.

CONCLUSIONS

Despite some limitations, our findings support the hypothesis that predominant polarity might be a useful specifier of bipolar disorder. Evidence quality was mixed, considering effects magnitude, consistency, precision and publication bias. Different predominant polarities may identify subgroups of patients with specific clinical characteristics.

First Genomic Insights Into The <em>Mandevilla</em> Genus.. [DOI: 10.20944/preprints202204.0255.v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Mandevilla (Apocynaceae) is a greatly appreciated genus in the world ornamental market. In this study, we attempted to address the poor genetic knowledge and the huge taxonomic gaps existing in this genus by analyzing the germplasm of 55 accessions. After cytometrically determining the triploid genome size (1,512.64 Mb) of a reference sample (variety &ldquo;Mandevilla 2001&rdquo;), the plastidial genome (cpDNA, 0,18 Mb) and a draft of the nuclear genome (nuDNA, 207 Mb) were assembled. While cpDNA was effective in reconstructing the phylogenesis of the Apocynaceae family based on a DNA superbarcoding approach, the nuDNA assembly length was found to be only 41% of the haploid genome size (506 Mb, predicted based on the K-mer frequency distribution). Its annotation enabled the prediction of thousands of genes, of which 5,275 resulted in full CDS. Among them, we identified nine genes whose orthologs (in Catharanthus roseus) encode enzymes involved in the biosynthesis of monoterpene indole alkaloids (MIAs), including catharanthine, tabersonine and vincadifformine. The nuclear genome draft was also useful to develop a highly informative (mean PIC=0.62) set of 23 SSR markers that was validated on the Mandevilla collection. These results were integrated with cytometric measurements, nuclear ITS1 haplotyping and chloroplast DNA barcoding analyses to assess the origin, divergence and relationships existing among the 55 accessions object of the study. As expected, based on the scarce information available in the literature, the scenario was extremely intricate. A reasonable hypothesis is that most of the accessions represent interspecific hybrids sharing the same species as maternal parent (i.e., Mandevilla sanderi).