Linear Indices Research Articles

Response to music on the nonlinear dynamics of human fetal heart rate fluctuations: A recurrence plot analysis.

Music has been shown to influence physiological functions in humans, but its effects on fetal heart rate variability (fHRV) are not well understood. This study aimed to assess the response of classical music exposure on the nonlinear behavior of fetal heart rate fluctuations in fetuses between 32 and 40 weeks of gestation using recurrence quantification analysis (RQA). We collected R-R time series from 37 fetuses in the third trimester following a study into four stages: PRE (baseline), STIM1 (first musical piece), STIM2 (second musical piece), and POST (post-exposure). The fetal R-R time series from each stage were evaluated using RQA indices such as determinism (DET), average diagonal line length (L), maximum line length (LMAX), entropy (ENTR), and trapping time (TT), as well as conventional linear indices like SDRR (standard deviation of R-R intervals). Results revealed three main points. First, there was an increase in DET, L, LMAX, and TT, with a decrease in ENTR in the POST stage compared to PRE, indicating more regular and predictable patterns. Second, the STIM2 stage enhanced the predictability and stability of cardiac dynamics compared to PRE, as indicated by L, LMAX, and TT. Third, no significant changes were observed in conventional indices, except for an increase in SDRR in the POST stage compared to STIM1. These findings suggest a reduction in complexity and nonlinear behavior of fHRV patterns after musical stimulus. The increase in SDRR during the POST stage appears to coincide with fetal movements, as indicated by the number of fetal accelerations found.

A new approach for evaluating maize transgressive segregants and their three-way cross potential in the S4 convergent breeding population

The development of transgressive segregant (TS) selection on convergent breeding populations of S4 maize is a concept that is rarely applied. However, the development of TS is necessary to accelerate maize breeding pipelines. Therefore, the objectives of this study were (1) to develop the concept of TS selection and (2) to select S4 TS maize to be developed as hybrid cross parents. The study was carried out using two experiments. The first experiment was designed with an augmented design of 6 replications for control genotypes. This design is just one factor focused on maize genotypes. However, it was divided into two sets: non-replicated of 32 TS lines and replicated of four check hybrid varieties. The second experiment focused on validation using a three-way cross. The experiment used a randomized complete block design with three replications. Based on the resulting study, the combination of ratio analysis, path analysis, best linear unbiased prediction, relative fitness, and selection indices is an objective approach to assessing the genetic potential of the S4 TS. The selection index formed was 0.53 ear weight + 0.24-grain yield percentage + yield. The index selection resulted in 11 S4 TS lines being further evaluated for their hybrid potential, with the TS line CB2.23.1 being the best. However, these TSs are expected to focus on identifying and combining ability through diallel crosses in the future. Furthermore, the three-way cross hybrid lines assessment also revealed SG 3.35.12 × JH37 F1 and CB 2.23.1 × JH37 F1 to be promising hybrid lines.

Dynamical complexity of postural control system in autism spectrum disorder: a feasibility study of linear and non-linear measures in posturographic analysis of upright posture

BackgroundAutism Spectrum Disorder (ASD) is a neurodevelopmental disorder, characterized by impairments in social interaction and communication with restricted and repetitive behavior. Postural and motor disturbances occur more often in ASD, in comparison to typically developing subjects, affecting the quality of life. Linear and non-linear indexes derived from the trajectory of the center of pressure (COP) while subjects stand on force platforms are commonly used to assess postural stability. The aim of the present feasibility study was to investigate whether combining linear and non-linear parameters of the COP during stance in subjects with ASD, could provide insight on specific features of motor dysfunction possibly linked to ASD cognition and clinical characteristics.MethodsTwenty-two males, aged 10–15 years, including subjects with ASD and healthy controls (N = 11, respectively), were studied. They all had normal cognitive level and independent walking ability. A piezoelectric force platform was used to evaluate posture over three feet positions, with eyes open, closed and during visually-guided saccades. Linear (sway path, total area and root mean square) and non-linear parameters (fractal dimension and sample entropy) of the COP were measured to determine postural stability and the complexity and regularity of the COP signals. GLMM analyses were performed to assess COP parameter changes across experimental conditions and subject groups. Finally, Spearman correlations evaluated the significance of potential relationships between linear and non-linear measures as well as between non-linear parameters and clinical data in patients with ASD.ResultsCompared to controls, subjects with ASD showed reduced postural stability and complexity, with higher regularity of COP trajectories, particularly in the most unstable feet positions, during visually-guided saccades and in the medial-lateral direction. Spearman correlations indicated that, in the patients’ group, postural instability was associated with a decrease in the geometric complexity and an increase in the regularity of the COP trajectory. Moreover, the increase in regularity of the COP trajectory was associated to the severity of restricted and repetitive behavior.ConclusionsThe results of this study highlight the importance of combining linear and non-linear measures in evaluating postural control in patients with ASD, also with respect to the outcome of interventions on these patients targeting postural balance.

Surgical Correction of Unicoronal Synostosis: Fronto-orbital Distraction versus Calvarial Switch.

There is a need for a new, less invasive surgical option for unicoronal synostosis (UCS). The aim of this study was to compare the resulting morphology and symmetry in patients with UCS following fronto-orbital distraction (FOD) or calvarial switch (CS). 79 patients with isolated UCS operated between 2005 and 2021 were analyzed. Follow-up was until 3 years of age. Angles describing orbital dystopia (ODA) and the anterior cranial fossa deviation and cant (ACFD and ACFC, respectively) were measured. Key linear dimensions, cranial cavities, and indices were calculated. 66 patients were included (14 in the FOD group and 52 in the CS group). The 3-year follow-up revealed significant improvement in all angles in both groups, with significant superiority in ODA correction following FOD (median improvement of 5.7 degrees as compared with 3.3 degrees after CS). Additionally, nasal and orbital volumes tended to be smaller, especially following CS; however, FOD resulted in a smaller absolute difference in orbital volume. Asymmetry in the orbital, nasal, and sphenoid regions also improved at the 3-year follow-up in both groups, although FOD resulted in complete normalization of the affected orbital shape and significantly improved overall asymmetry relative to that observed in the CS group. This study found that FOD achieves superior overall symmetry, as well as better shape correction of the cranium, as compared with CS, while also being less invasive. These findings suggest FOD as a safe and effective alternative to correct UCS and possibly the preferred surgical method.

Topology of quasi divisor graphs associated with non-associative algebra

The visualization of graphs representing algebraic structures has increasingly gained traction in chemical engineering research, emerging as a significant scientific challenge in contemporary studies. Due to their practical applications, graphs associated with groups and various algebraic systems have garnered significant interest in academic literature. Chemical graph theory employs graphs to illustrate molecular structures, where vertices symbolize atoms and edges represent bonds. The structure of quasi divisor graphs linked to non-associative algebra, including quasigroups and loops, presents numerous potential implications and wider applications. These applications span multiple disciplines, such as algebra, combinatorics, computer science, and network theory. Latin squares are tabular representations of quasigroups, generalizations of group structure. Numerous classifications of quasigroups exist in academic literature, such as Moufang quasigroups, Bol quasigroups, and alternative quasigroups. However, the structural characteristics of quasigroups exhibiting the weak inverse property closely resemble those of groups. The overall purpose of this study is to see the interrelationship between non-isomorphic quasi divisor graphs and a particular class of G-loops. To achieve our results, we employ a variety of methods, including a combinatorial approach, degree counting techniques, vertex and edge partitioning methods, as well as graph-theoretical tools and analytical procedures. In this paper, we compute a few topological indices based on degree, distance, and degree-distance using the structural aspects of quasi divisor graphs of orders 2φ,22ϕ,23ϕ and 4ϕ1ϕ2 where φ is a positive integer and ϕ1,ϕ2 are odd primes with ϕ1<ϕ2. This work also includes polynomial forms and their geometrical interpretations connected to linear, quadratic and higher degree topological indices of quasi divisor graphs associated with a class of non-commutative weak inverse property quasigroups.

Synthesis and characterization of piperazine nitrate monochloride semi-organic single crystal for NLO applications

A semiorganic single crystal of piperazine nitrate chloride (PNC) was grown utilising the gradual evaporation solution technique at ambient temperature. The crystal lattice properties and molecular structure of the formed crystal of PNC were identified via X-ray diffraction examination of a single crystal and are consistent with the monoclinic crystal system with space group P21/n. Using Hirshfeld surface analysis, intra and intermolecular interactions were displayed. The FTIR spectrum analysis presented here examines the vibratory patterns of several functional sections found within the PNC crystal. The crystal exhibits a low absorbance throughout the entire visible spectrum according to studies of UV–vis-NIR absorbance and calculated band gap as well as optical constants. TG/DTA analysis was used to identify the stability and breakdown properties. This refractive index was computed using the prism coupling method. At different temperatures studies of the dielectric properties were conducted and the Vickers hardness technique was employed to investigate the mechanical properties. The grown crystal's laser-damaged threshold value was found. The Z-scan method investigates a PNC crystal’s third-order NLO behaviours. This method makes it possible to calculate the material's linear and nonlinear refractive indices. The PNC crystal exhibits strong third-order nonlinear optical properties, crucial for applications in optical switching and NLO devices.

Cardiovascular responses as predictors of mortality in children with acute brain injury.

Investigate the utility of cardiovascular responses such as heart rate (HR), blood pressure (BP), and heart rate variability (HRV) in the prognosis of children with acute acquired brain injury (ABI). Children under 18 years with severe acute acquired brain injury (ABI) who survived at least 12 h after PICU admission were included in a prospective observational cohort in a tertiary academic PICU. Physiological variables, neurological data, laboratory tests (chemistry and hematology), and medications were recorded within 12 h of admission. Linear and nonlinear HRV indices, CT scans, PICU scores, and survival rates were evaluated. Seventy-two children, median age 10.7 years (IQR 4.1-13.6), were eligible for the study; 28 (38.9%) were diagnosed with brain death (BD). Tachycardia, SBP and MBP < 5th percentile, and MBP and DBP> 99th percentile were significantly associated with mortality. Poincaré SD1/SD2 was significantly associated with mortality after adjusting for age, sex and ongoing medication. Tachycardia, systolic hypotension and median hypo and hypertension were associated to mortality in children with severe ABI. While further validation through larger, multicenter studies is necessary, the Poincaré SD1/SD2 ratio has shown promise as a prognostic tool for predicting mortality in children with severe ABI. This study explores cardiovascular changes, including heart rate and blood pressure, and linear/nonlinear HRV measures using ECG at 1000 Hz, and compare them with other prognostic factors like brain tomography and PICU scores. Tachycardia, hypo/hypertension in the early hours after admission are linked to early mortality in children with severe traumatic and non-traumatic brain injury. Linear/non-linear measures of HRV were also related to survival. Higher HRV values indicating better survival chances. We identified Poincaré SD1/SD2 ratio as a promising tool for predicting mortality in children with severe ABI.

Ready-to-use Models Built Using a Diverse Set of 266 Aroma Compounds for the Estimation of Gas Chromatographic Retention Indices for the 50%-Cyanopropylphenyl-50%-Dimethylpolysiloxane Stationary Phase.

Retention index prediction based on the molecule structure is not often used in practice due to low accuracy, the need to use paid software to calculate molecular descriptors (MD), and the narrow applicability domain of many models. In recent years, relatively accurate and versatile deep learning (DL)-based models have emerged. These models are now used in practice as an additional criterion in gas chromatography-mass spectrometry identification. The DB-225ms stationary phase (usually described as 50%-cyanopropylphenyl-50%-dimethylpolysiloxane in available sources) is widely used, but ready-to-use retention index estimation models are not available for it. This study presents such models. The models are linear and use simple constitutional MD and retention indices predicted by DL for the DB-WAX and DB-624 stationary phases as MD (we show that it is their use that allows us to achieve satisfactory accuracy). The accuracy obtained for a completely unseen hold-out test set: root mean square error 73.2; mean absolute error 45.7; median absolute error 22.0. The models were trained using a retention data set of 266 volatile compounds. All calculations can be performed using the convenient open-source software CHERESHNYA. The final equations are implemented as a spreadsheet and a code snippet and are available online: https://doi.org/10.6084/m9.figshare.26800789.

Cardiac chamber three-dimensional volumes and deformation predict clinical outcomes in chronic mitral regurgitation

Abstract Background In patients with mitral regurgitation (MR), cardiac remodeling assessed by two-dimensional (2D) echocardiographic linear indexes is highly variable and not suitable for individualized risk assessment. Purpose To evaluate whether measurements of myocardial strain and left atrial (LA), left ventricular (LV) and right ventricular (RV) three-dimensional (3D) volumes improve risk assessment in MR. Methods In the prospective 3D Echocardiography and Cardiovascular Prognosis in Mitral Regurgitation study (3D-PRIME), 176 patients with significant (moderate or greater) MR were investigated with 2D/3D echocardiography. Referral criteria for mitral intervention followed current guidelines. LA remodeling was assessed by the maximum and minimum 3D LA volume (3D-LAV), peak reservoir strain (LASr), and stiffness (i.e. the ratio: mitral peak E-wave divided by the annular e’ velocity (E/e´) / LASr). LV and RV were considered dilated in case of increased 3D end-diastolic (LV&amp;gt;=86/74 and RV&amp;gt;=87/74ml/m2 in men/women) and end-systolic volumes indexed for body surface area (LV&amp;gt;=41/33 and RV&amp;gt;=44/36ml/m2 in men/women). Peak global longitudinal strain was measured in the LV (LV-GLS) and the RV free wall (RV-FWS). The primary outcome was a composite of mitral valve surgery, percutaneous mitral edge-to-edge repair and death. Results During a 14 [8-24] months follow-up, the patients (70±13 years, 39% women) experienced 73 events including 14 deaths. In univariate survival analyses, LV and RV dilatation, but not LV-GLS and RV-FWS, were associated with the primary outcome (Figure) and had superior predictive value to 2D volumes and diameters (p&amp;lt;0.05). On contrary, both atrial size and function predicted outcome, with 3D-LAV (HR 1.01, 95% CI 1.00-1.01), LASr (HR 1.03, 95% CI 1.01-1.06) and increased LA stiffness (Figure) all significant predictors of events (p&amp;lt;0.05). In multivariate Cox analysis with adjustment for age, sex, body mass index and MR etiology, dilated LV (HR 2.6, 95% CI 1.5-4.4), dilated RV (HR 2.0, 95% CI 1.1-3.6) and increased LA stiffness ((HR 2.4, 95% CI 1.3-4.6) were independently associated with higher rate of events (p&amp;lt;0.05). Conclusion In patients with moderate or greater MR, increased cardiac chamber 3D volumes and LA stiffness, as well as impaired LA reservoir strain are associated with higher risk of disease progression towards mitral valve intervention and death. Our findings indicate that assessment of both cardiac chamber 3D size and LA deformation can contribute to increased diagnostic and prognostic precision in patients with MR.

Entire loosening stage monitoring of bolted joints via nonlinear electro-mechanical impedance spectroscopy

This article proposes a nonlinear electro-mechanical impedance spectroscopy (NEMIS) methodology for the entire loosening stage monitoring of bolted joints. Unlike the conventional electro-mechanical impedance spectroscopy (EMIS) implemented in the frequency domain, NEMIS utilizes a temporal interrogating signal to procure the developed nonlinear impedance spectrum. It can harness the structural resonance information akin to the conventional EMIS, while concurrently capturing the contact acoustic nonlinearity (CAN) features with only one solitary Piezoelectric Wafer Active Sensor (PWAS). To elucidate the underlying principles of NEMIS, a comparative analysis juxtaposing the conventional EMIS, nonlinear ultrasonic techniques, and the proposed NEMIS was conducted. Subsequently, a reduced-order analytical model was established to simulate the rough contact interfaces of the bolted joints under various looseness states. Parametric studies were carried out to demonstrate the resonance deviation and nonlinear features resulting from the bolt looseness. Ultimately, the experimental implementation of NEMIS for the entire loosening stage monitoring of the bolted joint was performed compared with the conventional EMIS method. It was proved that NEMIS could detect both the incipient bolt loosening at an embryo stage and severe loosening of the bolted joint at the terminal period, integrating the continuous monitoring capability of conventional EMIS and the sensitivity of nonlinear ultrasonic methodology. The quantification on the severity of bolt loosening was accomplished via both linear and nonlinear damage indices, exhibiting a consistent trend with the gradations of bolt looseness. The article culminates in a summary, concluding remarks, and suggestions for future work.

Left atrial volume and function in Cavalier King Charles spaniels at different ACVIM stages

BackgroundThe correct assessment of left atrial size and function is essential to evaluate the severity of degenerative mitral valve disease in dogs. Hypothesis/objectivesEvaluate left atrial (LA) dimension and function in Cavalier King Charles Spaniel (CKCS) at different ACVIM stages and the accuracy of linear and volumetric indexes to assess LA enlargement. AnimalsOne hundred and ninety-eight privately owned CKCS. MethodsMulticentric prospective observational cross-sectional study. Dogs underwent an echocardiographic exam for breed screening or cardiac examination. Linear and volumetric echocardiographic LA size and function indexes were compared between classes. ResultsDogs were allocated as follows: 43 in class ACVIM A, 58 ACVIM B1, 55 ACVIM B2, and 42 ACVIM C/D. Only LA anteroposterior diameter normalized on body weight (LADn) and LA maximal, minimal and P volumes (LAVmax, LAVmin, LAVP) differed across all pairwise comparisons. Active LA emptying fraction (aLAEF) was higher in class B1 compared to class A (P < .001), and then decreased in class C/D compared to class B2 (P < .001). This suggests an increase in the left atrial active component due to the Frank-Starling mechanism in ACVIM B1 dogs, and the presence of atrial dysfunction in symptomatic dogs. Conclusions and clinical importanceThe LADn and LAV are higher in CKCS in class ACVIM B1 compared to class ACVIM A, suggesting the presence of LA remodelling at the early stages of the disease. Atrial dysfunction is evident in symptomatic dogs.

Emaciated enigma: Decline in body conditions of common dolphins in the Celtic Seas ecoregion

AbstractMonitoring the nutritional health of cetaceans has become increasingly important in a changing environment, where multiple stressors impact animals. Particularly for those species that require consumption of energy‐dense prey, such as the common dolphin. Thus far, no uniform measure for monitoring body condition has been recommended across cetaceans, and species‐specific measures may need to be developed if employed as a population condition indicator under Descriptor 1 of the Marine Strategy Framework Directive. Here, nine morphometric body condition indices were applied to long‐term common dolphin stranding data sets originating from Ireland and the UK. We report a recent decline in the nutritional health of common dolphins in the Celtic Seas ecoregion comparing animals from 2017 to 2019 to animals from 1990 to 2006, with an increase in cases of animals dying due to starvation. Using ordinal regression trees, ventral blubber thickness (VBT) was identified as the most important index to predict nutritional status, defined at necropsy, followed by the scaled mass index (SMI). Using generalised linear models, both the VBT and SMI indices differentiated individuals that died from chronic and acute causes of death (i.e., bycatch), where animals in chronic conditions had significantly thinner VBT and lower SMI. Both significant temporal and seasonal patterns in VBT were identified, with poorer body conditions observed during the autumn and better body conditions observed during the spring, as well as an overall decline detected in VBT during the study period. While VBT was positively correlated with total body length, SMI showed the opposite trend. The VBT index is recommended for monitoring nutritional health within the species when total body length and season are considered. Further research is needed to understand the underlying causes for the observed decline, including shifts in prey availability and/or quality, to inform targeted conservation management strategies.

Recurrence quantification analysis of uterine vectormyometriogram reveals differences between normal-weight and overweight parturient women

Objective.This study aims to use recurrence quantification analysis (RQA) of uterine vectormyometriogram (VMG) created from the slow wave (SW) and high wave (HW) bands of electrohysterogram (EHG) signals and assess the directionality of the EHG activity (horizontal orX, vertical orY) in normal-weight (NW) and overweight (OW) women during the first stage of labor.Approach. The study involved 41 parturient women (NW = 21 and OW = 20) during the first stage of labor, all of whom were attended at the Gynecology and Obstetrics Hospital of the Maternal and Child Institute of the State of Mexico in Toluca, Mexico. Twenty-minute EHG signals were analyzed in horizontal and vertical directions. Linear and nonlinear indices such as dominant frequency (Dom), Sample Entropy (SampEn), and RQA measures of VMG were computed for SW and HW bands.Main results. Significant differences in SampEn and Dom were observed in the SW band between NW and OW in bothXandYdirections, indicating more regular dynamics of electrical uterine activity and a higher Dom in NW parturient women compared to OW women. Additionally, the RQA indices calculated from the VMG of SW were consistent and revealed that NW women exhibit more regular dynamics compared to OW women.Significance. The study demonstrates that RQA of VMG signals and EHG directionality differentiate uterine activity between NW and OW women during the first stage of labor. These findings suggest that the uterine vector may become more periodic, predictable, and stable in NW women compared to OW women. This highlights the importance of tailored clinical strategies for managing labor in OW women to improve maternal and infant outcomes.

Informatic application to characterise and identify small mammal species: Arvicolinae (Cricetidae, Rodentia, Mammalia)

AbstractThe classification of rodent species can be challenging due to high morphological similarities observed among them. This problem is further increased in palaeontological systematics, where classification is traditionally based on the molar morphology. The subfamily Arvicolinae (Rodentia, Mammalia) is one of these rodent groups, whose classification being important for biostratigraphic and climatic studies of the Quaternary period is challenging. We present an application developed using the MatLab informatic algorithm, designed to classify the Arvicolinae species using Geometric Morphometrics (GMM) analyses of the first lower molar. Moreover, the application includes an option to automatically obtain the linear measurements that are commonly used for the identification of these species. This method shows a high degree of accuracy in the species classification, which is expected to increase as the reference database is further developed. This application can serve as an alternative tool for the classification of specimens with unclear morphologies. It can also be used to reduce the time required to manually obtain the linear indices necessary for their classification.

Examining The Relationship Between Lateral Ventricle Volumetric Index and Linear Indexes in Childhood and Adolescence: A Retrospective MRI Study

Objective: Indexes obtained from two-dimensional and three-dimensional measurements are used to evaluate the brain's lateral ventricle (LV) structure. However, there were limited studies on how well the Evans index (EI) and the Bicaudate index (BI), which estimate LV volume, represent the LV volumetric index (LVVI) in the childhood and adolescence period. This study investigated the relationship between LVVI and linear indexes (EI and BI) in the pediatric period regarding age and sex factors. Method: This study was performed retrospectively in 588 individuals (267 [45.4%] females) aged 1-18 years with normal brain magnetic resonance images (MRI) between 2012 and 2021. LVVI was obtained by segmenting three-dimensional T1-weighted MRIs with volBrain1.0. LVVI was obtained by dividing the LV absolute volume by the total intracranial volume. We made linear measurements for EI and BI with the 3D Slicer. In this study, we compared the data obtained from individuals in 16 different age ranges between 1-18 years old with SPSS (ver.28). Results: In our study, we found the mean value of LVVI to be 0.656±0.372%. The mean values of EI and BI were 0.242±0.025 and 0.070±0.022, respectively. In the pediatric population, we found that mean values of EI and BI were significantly higher in males than in females (p

Influence of La3+ ions on the structural, elastic, optical, and radiation shielding properties of Cr2O3-Doped heavy metal glasses

This study investigates the effect of La³⁺ rare earth ions on the structural, elastic, optical, and radiation shielding features of heavy metal borate glass (B₂O₃-PbO) doped with Cr₂O₃. Density measurements and FT-IR spectra analysis revealed the role of La3+ ions as a network modifier, where successive additions of La2O3 content led to a gradual increase in the density and an increase in the non-bridging oxygen content resulting from the structural transformation between the BO4 and BO3 units. The significant improvement in the elastic modulus and microhardness factor moduli was confirmed by calculating the change in ultrasonic velocities through the glassy system. The structural modifications induced by La³⁺ ions narrowed the band gap and increased the Urbach energy, indicating higher disorder within the glass network. The linear refractive indices increased due to increased optical basicity and electronic polarization. Optical absorption results showed that Cr⁶⁺/Cr³⁺ ions occupy octahedral/tetrahedral sites, with the tendency for Cr³⁺ cations to occupy more octahedral sites with increasing La₂O₃ content. The produced samples showed a greenish-yellow color caused by the absorption band centered at ∼415 nm associated with the electronic transition ⁴A₂g(F)→2Eg(G). The ligand field effect highlighted the significance of La³⁺ cations in increasing the crystalline field intensity surrounding Cr³⁺ cations and reducing the nephelauxetic ratio, signifying enhanced covalent character between Cr³⁺ cations and neighboring ions. Moreover, the radiation shielding capabilities of the glassy system were analyzed and compared with standard shielding materials, confirming superior shielding performance in samples with the highest La₂O₃ content.

Cerium oxide-reinforced Fe2O3–Na2O–SiO2–B2O3 glass matrix for protection against ionizing X and gamma rays

Radiation shielding glass is an interesting material in the field of radiation shielding due to its remarkable features. In the present paper, we investigated the physical properties of radiation-shielding glass materials that consist of sodium oxide (Na2O), cerium oxide (CeO2), and iron oxide (Fe2O3) incorporated into borosilicate glasses with the formula 90SiO2-(70-x)B2O3+ 20Na2O–1Fe2O3-xCeO2 (CeFeNaBS-glasses). One of the distinguishing characteristics of this glass system is its enhanced radiation shielding capabilities. The structural studies indicated a gradual rise in glass density from 1.954 to 2.658 g/cm with further CeO2 doping. Optical studies showed that the optical band gaps went down from 3.41 eV to 3.33 eV as the amount of CeO2 in the CeFeNaBS-glass matrix rose. The decrease in optical band gap has been correlated with the rising basicity. Also, the increased basicity behavior induces more conversion of Ce3+ to Ce4+ ions by losing a 4f electron. Moreover, with further CeO2 additions, the glass color changed from light brown to dark brown. The presence of Ce4+ ions with further CeO2 additions is responsible for this color transformation. The linear and non-linear refractive indices exhibit enhanced behaviors with higher CeO2 concentrations. We used declining basicity and polarizability behaviors to describe this behavior. The incorporation of larger CeO2 concentrations enhances the ability to improve radiation shielding properties, as demonstrated by the increased values of the mass attenuation coefficient and half-value layer, especially in the energy ranges of soft tissues X-ray and hard tissues X-ray. Hence, the investigated CeFeNaBS-glasses exhibit enhanced transparency and radiation shielding capabilities, rendering them highly suitable for implementation in this domain.

Parallel coupling of gas chromatography to mass spectrometry and solid deposition Fourier transform infrared spectroscopy: an innovative approach to address challenging identifications.

The request for novel hyphenated instruments and techniques, capable of affording exhaustive information and results, is a focus continuously watched out. In this context, the present work aimed at the development of an integrated system combining gas chromatographic (GC) separation with mass spectrometry (MS) and (solid deposition) Fourier transform infrared spectroscopy (FTIR) detection. An external transfer line was designed inthelab for the parallel coupling of the two detectors, in such a way toobtain complementary analytical information consisting of anMS spectrum, anIR spectrum and linear retention indices (LRI), within a single analysis. The instrument performance was demonstrated for the analysis of a commercial mixture consisting of 139 hydrocarbons, comprising linear, branched, unsaturated and aromatic compounds. A 100-m poly(dimethylsiloxane) column was employed for the separation, and the outlet flow was split 95:5 between the IR and MS detectors using two uncoated capillaries. The IR spectra were acquired from solid deposits on a zinc selenide disc (-90 °C), over a spot (detector area) of about 0.1 mm2, in the range of 4000-700 cm-1 and at a resolution of 4 cm-1. Final identification of the separated compounds by alibrary search was achieved by excluding incorrect results, sequentially using a three-filter approach (85% similarity against reference MS and IR library spectra and ±10 LRI unit tolerance). Based on these preliminary results, the GC-MS/sd-FTIR system is a promising tool for the characterization of complex matrix constituents, for which identification is cumbersome, by using only one detection technique.

Formulation of dynamic damage features sensitive to local fatigue cracks in steel bridges: Numerical study

Fatigue cracks commonly emerge within welding areas of steel bridges with orthotropic decks during the long-term operation. Dynamic-based detection presents an appealing method for detecting such fatigue cracks within steel bridges. Traditional linear dynamic indexes are not significantly affected by the small size of the damage, exhibiting the insensitivity to local fatigue cracks across the entire steel bridges. This study aims to address the dynamic insensitivity and find some potential damage features with practical utility. The fatigue cracks found on the Türr Istvan bridge spanning the Danube River in Hungary are presented, and the bridge models with two types of cracks are established. The local dynamic characteristics of the concerned substructures are isolated from the global characteristics of the entire bridge and used to reflect the local damage information. Accordingly, three potential strategies, namely, (i) impacting vertical ribs to obtain local frequencies, (ii) frequency sweeping the entire bridge system to induce local modes of the longitudinal girders, and (iii) pairwise monitoring of local strains near the crack, are proposed. Numerical results highlight that the sensitivity of local frequencies of vertical ribs is higher than that of global frequencies. The correlation coefficients of the pairs of strains between a crack are significantly decreased compared with those of the uncracked areas. The resonance peaks of the local modes induced by the local frequency-swept excitation migrate leftward while the resonance peaks of the global modes remain unchanged when a crack occurs. The superiorities of three damage features are numerically validated and expected to overcome the insensitivity of the existing dynamic detection methods in detecting local fatigue cracks within steel bridges.

Neuromuscular conditions in post-stroke ankle-foot dysfunction reflected by surface electromyography

BackgroundRating scales and linear indices of surface electromyography (sEMG) cannot quantify all neuromuscular conditions associated with ankle-foot dysfunction in hemiplegic patients. This study aimed to reveal potential neuromuscular conditions of ankle-foot dysfunction in hemiplegic patients by nonlinear network indices of sEMG.MethodsFourteen male patients with hemiplegia and 10 age- and sex-matched healthy male adults were recruited and tested in static standing position. The characteristics of the root mean square (RMS), median frequency (MF), and three nonlinear indices, the clustering coefficient (C), the average shortest path length (L), and the degree centrality (DC), of eight groups of muscles in bilateral calves were observed.ResultsCompared to those of the control group, the RMS of the medial gastrocnemius (MG), flexor digitorum longus (FDL), and extensor digitorum longus (EDL) on the affected side were significantly lower (P < 0.05), and the RMS of the tibial anterior (TA) and EDL on the unaffected side were significantly higher (P < 0.05). The MF of the EDL on the affected side was significantly higher than that on the control side (P < 0.05). The C of the unaffected side was significantly higher than that of the control group, whereas the L was lower (P < 0.05). Compared to those of the control group, the DC of the TA, EDL, and soleus (SOL) on the unaffected sides were higher (P < 0.05), and the DC of the MG on the affected sides was lower (P < 0.05).ConclusionThe change trends and clinical significance of these three network indices, including C, L, and DC, are not in line with those of the traditional linear indices, the RMS and the MF. The C and L may reflect the degree of synchronous activation of muscles during a certain motor task. The DC might be able to quantitatively assess the degree of muscle involvement and reflect the degree of involvement of a single muscle. Linear and nonlinear indices may reveal more neuromuscular conditions in hemiplegic ankle-foot dysfunction from different aspects.Trial registrationChiCTR2100055090.