Large Fiber Research Articles

Understanding neuropathic pain: the role of neurophysiological tests in unveiling underlying mechanisms

AbstractNeuropathic pain, arising from lesions of the somatosensory nervous system, presents with diverse symptoms including ongoing pain, paroxysmal pain, and provoked pain, usually accompanied by sensory deficits. Understanding the pathophysiological mechanisms behind these symptoms is crucial for targeted treatment strategies. Neurophysiological techniques such as nerve conduction studies, reflexes, and evoked potentials help elucidate these mechanisms by assessing large myelinated non-nociceptive fibres and small nociceptive fibres. This argumentative review highlights the importance of tailored neurophysiological assessments for improving our understanding of the pathophysiological mechanisms behind neuropathic pain symptoms.

Clinical and neurophysiological aspects of peripheral neuropathy in patients with myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal disorders, manifesting multiple clinical autoimmune inflammatory phenomena, including rarely peripheral neuropathy. Twenty-four patients diagnosed with MDS and 29 healthy subjects were enrolled in this prospective study in a 5-year period. Every subject was assessed by symptoms questionnaire and clinical neurological examination followed by nerve conduction studies, quantitative sensory testing and skin biopsy. Peripheral neuropathy was diagnosed in 12 subjects (50%). Our study indicated that peripheral neuropathy involving large and small nerve fibres, with a symmetrical length-dependent pattern, is not uncommon between patients with MDS.

The Value-added Catalog of OB Stars in LAMOST DR7

In this work, we update the catalog of OB stars based on the Large Sky Area Multi-Object Fiber Spectroscopic Telescope data release 7 and modify the OB stars’ selection criteria in spectral line indices’ space. The new catalog includes 37,778 spectra of 27,643 OB stars, of which 3827 OB stars are newly identified. The spectral subclasses of 27,643 OB stars are obtained using the automatic classification code MKCLASS. We find that the modified OB star selection criteria can better improve the completeness of late B-type stars by analyzing their spectral classification results given by MKCLASS. We also identify 3006 Be-type stars or candidates by examining the Balmer lines in their spectra and find that the frequency of our Be-type stars (10.9%) is consistent with previous results. The spatial distribution of OB stars indicates that they are mainly located in the Galactic disk. This new catalog of OB stars will provide valuable data for studying the structure and evolution of the Milky Way.

Influence of stitching on the interlaminar fracture toughness energy – modes I and II – of unidirectional GFRP

Abstract The influence of stitching on the delamination resistance of unidirectional glass fiber-reinforced plastic laminates depends strongly on the loading mode. The application of a lock stitch with a stitch density of 3.4 cm−1 perpendicular to the fibers results in an increase of the interlaminar fracture toughness energy, mode I, G IC by a factor of 2.7 compared to an unstitched reference laminate. The Kevlar threads are pulled out of one half of the DCB specimen leaving large frayed fiber bundles sticking out of the other half. The same stitching, however, does not improve the interlaminar fracture toughness energy, mode II, G IIC. The Kevlar threads are not able to deform the surrounding matrix thereby expending additional energy. They fail directly at the mid-plane of the ENF specimens. An increased stitch density of 11.6 cm−1 can be expected to lead to a further significant increase in the G IC value. But the tight stitching pattern causes the bonded metal hinges to tear off. The force introduction would have to be changed to enable testing of corresponding DCB and subsequently ENF specimens.

Spectrum of hereditary transthyretin amyloidosis due to T60A(p.Thr80Ala) variant in an Irish Amyloidosis Network

BackgroundVariant transthyretin amyloidosis (ATTRv) is a hereditary multisystem disorder with clinical spectrum ranging from predominant cardiomyopathy to polyneuropathy. In the Irish population, the T60A mutation has been previously recognised as...

Estimating Stellar Atmospheric Parameters and [α/Fe] for LAMOST O-M-type Stars Using a Spectral Emulator

In this paper, we developed a spectral emulator based on the Mapping Nearby Galaxies at Apache Point Observatory Stellar Library (MaStar) and a grouping optimization strategy to estimate effective temperature (T eff), surface gravity (log g), metallicity ([Fe/H]), and the abundance of alpha elements with respect to iron ([α/Fe]) for O-M-type stars within the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) low-resolution spectra. The primary aim is to use a rapid spectral-fitting method, specifically the spectral emulator with the grouping optimization strategy, to create a comprehensive catalog for stars of all types within LAMOST, addressing the shortcomings in parameter estimations for both cold and hot stars present in the official LAMOST AFGKM-type catalog. This effort is part of our series of studies dedicated to establishing an empirical spectral library for LAMOST. Experimental results demonstrate that our method is effectively applicable to parameter prediction for LAMOST, with the single-machine processing time within 70 hr. We observed that the internal error dispersions for T eff, log g, [Fe/H], and [α/Fe] across different spectral types lie within the ranges of 15–594 K, 0.03–0.27 dex, 0.02–0.10 dex, and 0.01–0.04 dex, respectively, indicating a good consistency. A comparative analysis with external data highlighted deficiencies in the official LAMOST catalog and issues with MaStar parameters, as well as potential limitations of our method in processing spectra with strong emission lines and bad pixels. The derived atmospheric parameters as a part of this work are available via doi:10.12149/101402.

Neurotization of Decellularized Muscle Graft Increases de novo Type I Slow Muscle Fiber Formation and Large Fiber Size Frequency

Neurotization of Decellularized Muscle Graft Increases de novo Type I Slow Muscle Fiber Formation and Large Fiber Size Frequency

Linking seedling wood anatomical trade-offs with drought and seedling growth and survival in tropical dry forests.

Wood anatomy plays a key role in plants' ability to persist under drought and should therefore predict demography. Plants balance their resource allocation among wood cell types responsible for different functions. However, it remains unclear how these anatomical trade-offs vary with water availability, and the extent to which they influence demographic rates. We investigated how wood anatomical trade-offs were related to drought and demographic rates, for seedling communities in four tropical dry forests differing in their aridity indexes (AIs). We measured wood density, as well as vessel, fiber and parenchyma traits of 65 species, and we monitored growth and survival for a 1-yr period. Two axes defined wood anatomical structure: a fiber-parenchyma axis and a vessel-wood density axis. Seedlings in drier sites had larger fiber but lower parenchyma fractions, while in less dry forests, seedlings had the opposite allocation pattern. The fiber-parenchyma trade-off was unrelated to growth but was positively related to survival, and this later relationship was mediated by the AI. These findings expand our knowledge about the wood anatomical trade-offs that mediate responses to drought conditions and influence demographic rates, in the seedling layer. This information is needed to anticipate future responses of forests to changing drought conditions.

10 W, 2 mJ-level ns all-fiber amplifier at 2.8 µm.

In this Letter, we demonstrate a single-stage erbium-doped fluoride fiber amplifier composed of two spliced large core fibers with respective diameters of 85 and 130 µm. An optical parametric generator (OPG) operating at a 5 kHz repetition rate, and providing ∼2 ns pulse duration, and an average output power of 500 mW at a wavelength of 2.8 µm was used as a seed source. This nanosecond amplifier configuration achieved an average output power of 10 W with a record pulse energy of 2 mJ, corresponding to 1 MW of output peak power. The maximum slope efficiency of this hybrid amplifier is 21% with respect to the total incident pump power at 940 nm. The presented master-oscillator power-amplifier (MOPA) configuration shows its potential for further power and energy scaling.

Fundamental Parameters of a Binary System Consisting of a Red Dwarf and a Compact Star

TIC 157365951 has been classified as a δ Scuti type by the International Variable Star Index. Through the spectra from Large Sky Area Multi-Object Fiber Spectroscopic Telescope and its light curve, we further discovered that it is a binary system. This binary system comprises a red-dwarf star and a compact star. Through the spectral energy distribution fitting, we determined the mass of the red dwarf star as M 1 = 0.31 ± 0.01M ⊙ and its radius as R 1 = 0.414 ± 0.004R ⊙. By fitting the double-peaked Hα emission, we derived the mass ratio of q = 1.76 ± 0.04, indicating a compact star mass of M 2 = 0.54 ± 0.01M ⊙. Using Phoebe to model the light curve and radial velocity curve for the detached binary system, we obtained a red dwarf star mass of M 1 = 0.29 ± 0.02M ⊙, a radius of R 1 = 0.39 ± 0.04R ⊙, and a Roche–lobe filling factor of f = 0.995 ± 0.129, which is close to the f = 1 expected for a semidetached system. The Phoebe model gives a compact star mass M 2 = 0.53 ± 0.05M ⊙. Constraining the system to be semidetached gives M 1 = 0.34 ± 0.02M ⊙, R 1 = 0.41 ± 0.01R ⊙, and M 2 = 0.62 ± 0.03M ⊙. The consistency of the models is encouraging. The value of the Roche–lobe filling factor suggests that there might be ongoing mass transfer. The compact star mass is as massive as a typical white dwarf.

Measuring the diffuse interstellar bands at 5780, 5797, and 6614 A in low-resolution spectra of cool stars from LAMOST

The limited number of high-resolution spectra of hot stars is inadequate for statistical studies of diffuse interstellar bands (DIBs). In contrast, the vast quantity of low-resolution spectroscopic surveys on cool stars holds great potential for investigating the relationship between DIBs and the known interstellar medium (ISM), as well as the spatial distribution of their unidentified carriers. We attempt to measure the DIBs $ 5797$, and $ 6614$ in over two million low-resolution spectra of cool stars from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). Based on these DIB measurements, we reviewed and investigated the correlation between DIBs and extinction; the kinematics of DIBs; and the Galactic distribution of DIBs from a statistical perspective. We developed a pipeline to measure the DIBs $ 5797$, and $ 6614$ in the LAMOST low-resolution spectra. Four modules in the pipeline consist of building the target and reference dataset; extracting the ISM residual spectra from the target spectra; measuring the DIBs in the residual spectra; and quality control of the measurements. We obtained DIB measurements of spectra of late-type stars from LAMOST, and selected 176,831, 13,473, and 110,152 high-quality (HQ) measurements of the DIBs $ 5797$, and $ 6614$, respectively, corresponding to 142,074, 11,480, and 85,301 unique sources. Using these HQ measurements, we present Galactic maps of the DIBs $ 5780$ and $ 6614$ in the northern sky for the first time. The central wavelengths of the DIBs $ 5797$, and $ 6614$ in air are determined to be $5780.48 0.02$, and $6613.64 respectively, based on their kinematics. A statistical fit of the equivalent widths of these three DIBs per unit extinction provides values of 0.565, 0.176, and 0.256 $ $. As a result of this work, three catalogs of the HQ measurements for the DIBs $ 5797$, and $ 6614$ are provided via https://nadc.china-vo.org/res/r101404/ To the best of our knowledge, this is the largest number of measurements of these three DIBs to date. It is also the first time that Galactic maps of the DIBs $ 5780$ and $ 6614$ in the northern hemisphere are presented, and that the central wavelengths of the DIBs $ 5797$, and $ 6614$ are estimated from kinematics.

The Cribellate Nanofibrils of the Southern House Spider: Extremely Thin Natural Silks with Outstanding Extensibility

AbstractCribellate silks, produced by ancient spiders, are fascinating because they feature a highly sophisticated, 3D hierarchical structure consisting of filaments with different diameters and shapes. Here, the smallest and thinnest constituents of the cribellate silk are investigated: nanofibrils that form a dense mesh that is supported by larger fibers. Analysis of their structure via atomic force and transmission electron microscopies shows that they are flattened fibrils, only ≈5 nm thick — thinner than any other natural spider silk fibrils previously reported. In this work, the first mechanical tensile testing experiments on these fibrils are carried out, which reveals that the fibrils show an outstanding extensibility of at least 1100%, almost twice as much as the most stretchable spider silk previously reported. Based on these extraordinary findings, this work significantly expands the parameter space of materials properties attainable by spider silks and provides further insights into their nanomechanics.

7087 An Unusual Movement Disorder, Case of Diabetic Striatopathy!

Abstract Disclosure: S. Azmat: None. O. Lodhi: None. R. Safi: None. H. harb: None. H. Ashok: None. M.F. Siddiqui: None. J.L. Gilden: None. Background: Non-ketotic Hyperglycemia Hemichorea-Hemiballismus Syndrome (NKH-CB) is rare complication of poorly controlled diabetes mellitus (DM) characterized by continuous, irregular jerky movements localized to one side of the body. It is commonly seen in type 2 DM and is often presented in females of East Asian descent. NKH-CB is often misdiagnosed due to its rarity and radiographic features easily mistaken for intracerebral hemorrhage.Case: A 70-year-old Latino male with type 2 diabetes mellitus, hypertension, bipolar disorder and past history of two cerebrovascular accidents presented to ED with non-radiating, midsternal chest pain. ACS was ruled out with negative serial troponins and normal EKG. Vital signs were significant for elevated blood pressure 151/64 mmHg. Labs showed blood glucose=447 mg/dL. Physical examination revealed large amplitude involuntary movements in left upper and lower extremities and facial region. He also veered to the left when ambulating. The patient reported that these abnormal movements were occurring for last three weeks although sensation was preserved bilaterally. Code stroke was called; non-contrast CT showed unilateral hyper density of the right caudate and putamen with no evidence of acute intracranial hemorrhage or large arterial territory infarction. CT Angiogram did not show any signs of stenosis or occlusion. He received intravenous fluids and 8 units lispro insulin in ED. Was admitted for further evaluation and received basal/bolus insulin therapy with target blood glucose of 140-160 mg%. He also received risperidone for his mental condition. Subsequent testing revealed hemoglobin A1C of 16.9% (reference range: < 5.7%). MRI Brian showed unilateral T1 hyperintensity involving right caudate and putamen corresponding to the hypodensity seen on CT. Neurology service was consulted. Based on clinical signs/symptoms coupled with neuroimaging, he was diagnosed with non-ketotic Hyperglycemia Hemichorea-Hemiballismus Syndrome. On day 2 with resolution of hyperglycemia, amplitude and frequency of involuntary arm movements were minimal. The patient was discharged with Lantus 7 and metformin 1000 mg for DM and risperidone for symptoms management. Conclusion: Diabetic neuropathy is commonly known to result in small and/or large fiber sensorimotor polyneuropathy, proximal motor, and acute mononeuropathies as well as entrapments, radiculopathies, autonomic neuropathies, and even cognitive disorders. This case describes rare case of simultaneous NKH-CB with history of CVA and antipsychotic medication use in a patient with poorly controlled DM which resolved with treatment of hyperglycemia. Thus offers valuable insights into the diagnostic challenges associated with this condition as well as potential links to other neurological complications. One should also remain vigilant of potential onset of seizures commonly seen with NKH. Presentation: 6/3/2024

Micromechanical analyses of unidirectional (UD) discontinuous flax fiber reinforced composites

Prediction of the strength and damage behavior of natural fiber composites is a challenging task due to computational difficulties resulting from large fiber aspect ratio, non-uniform fiber length distribution, and interface modelling. A computational micromechanical model, which solves the above-mentioned challenges by incorporating a novel representative volume element (RVE) generation algorithm inspired by Lennard-Jones potential, is developed to predict the tensile behavior of unidirectional (UD) flax/epoxy composites. Effects of fiber aspect ratio, fiber spatial distribution, interfacial and matrix properties on longitudinal modulus, strength, and the damage behavior of the flax/epoxy composites are extensively studied using the numerical model. The modulus and strength predicted by numerical model were compared with both analytical models and experimental results, which not only validated the numerical model but identified the limitations of analytical model. The longitudinal strength of flax/epoxy composites initially increased with fiber aspect ratio. Upon reaching certain fiber aspect ratio (25 in this study), strength predicted by both RVE (RVEs with many fibers) and unit cell (unit cells with two fibers) are close to experimental value (240 MPa). This finding provides confidence and guidance on how to use simplified unit cells to predict the strength of natural fiber composites with acceptable accuracy and much lower computational cost.

Pin-prick (Medipin) assessment for neuropathy in diabetes: Prospective screening study in primary care

AimsDiabetic patients are at elevated risk of neuropathy; early detection is desirable to minimise the risk of complications. The Medipin pin-prick device was appraised as a screening tool for diabetic neuropathy. MethodsProspective cross-sectional comparative screening study in primary care setting, involving 389 participants with type 2 diabetes mellitus. The Medipin pin-prick method, involving dorsal application on the hallux of both feet, was compared to 10 g monofilament testing. ResultsThe ternary and semi-quantitative approach for scoring Medipin pin-prick sensation give very similar results (Spearman rho 0.67, P < 0.001). A total of 59 % patients had no signs of neuropathy (sharp sensation), 38 % reported impaired sensation (dull sensation), and an absence of sensation occurred in 3 % of patients. For the monofilament dorsal method, the figures were 79 % no neuropathy, 14 % elevated risk, and 7 % neuropathy respectively, and with the monofilament plantar method 87 % of patients had no neuropathy and 13 % did. Correlation analyses showed that taller patients and those with existing neuropathic pain are at very modest increased risk of neuropathy. ConclusionsThe Medipin pin-prick device can identify diabetic neuropathy and detects (first signs of) neuropathy in relatively more patients than 10 g monofilament testing. The differential targeting of nerve types, namely predominant small (Medipin) versus large (monofilament) fibre, likely underpins the difference in outcomes.

Mira Variables Based on Emission Lines in LAMOST DR9

We present a sample of 335 Mira variables, extracted from DR9 of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey. These variables are characterized by the Balmer emissions (Hδ, Hγ, Hβ, and Hα) and the metal emissions (Fe i λ λ 4202, 4308, 4376, and Mg i λ4571) observed in M giant spectra. We distinguished oxygen-rich stars from carbon-rich stars through the identification of carbon molecular bands present in the optical spectra. For the oxygen-rich stars we examined multiple attributes, such as the link between line strength and bolometric luminosity, and the connection between atmospheric parameters and their periods. We observed that Fe i λ λ 4202, 4308 showed a significantly gradual progression, which can be postulated to trace the fluorescent emission resulting from pulsation shocks. Regarding the correlation between T eff and the period, T eff remains relatively constant over varying periods, with no clear trend, while both log g and [Fe/H] show a decreasing trend within a period range of 450 days, and this decreasing of the log g trend is consistent with the results in the literature. To shed more light on the variations of Balmer lines, we showcase time-series spectra for two objects, demonstrating that the Balmer lines reach their peak intensity during the brightest phase of the stellar cycle.

KM UMa: An Active Short-period Detached Eclipsing Binary in a Hierarchical Quadruple System

Abstract The first detailed photometric and spectroscopic analysis of the G-type eclipsing binary KM UMa is presented, which indicates that the system is a short-period detached eclipsing binary. The radial velocity curves were calculated using the cross-correlation function method based on Large Sky Area Multi-Object Fiber Spectroscopic Telescope, Sloan Digital Sky Survey, and our observations, which determined the mass ratio as q = 0.45 (±0.04). Based on the light curves from the Transiting Exoplanet Survey Satellite, other survey data, and our multiband observations, the positive and negative O’Connell effects have been detected evolving gradually and alternately over the last 20 yr, which can be explained by the presence of spots on the primary component. A superflare event was detected in the SuperWASP data on 2007 February 28, further indicating that KM UMa is a very active system. We calculated its energy to be 5 × 1034 erg by assuming it occurred on the primary star. Utilizing hundreds of medium-resolution spectra and one low-resolution spectrum, the equivalent width variations of the H α line were calculated, indicating the presence of a 5.21 (±0.67) yr magnetic activity cycle. The orbital period variations were analyzed using the O–C method, detecting a long-term decrease superimposed with a periodic variation. The amplitude of the cyclic variation is 0.01124 (±0.00004) day, with a period of 33.66 (±0.0012) yr, which exceeds the 5.21 yr activity cycle, suggesting that this is more likely attributable to the light travel time effect of a third body. Simultaneously, a visual companion has been detected based on the Gaia astrometric data, indicating that KM UMa is actually in a 2+1+1 hierarchical quadruple system.

Physical Parameters and Magnetic Activity of M-type Stars Based on the LAMOST DR9, SDSS, and TESS Surveys

We analyze a catalog comprising 781,232 spectra from 641,095 M dwarf stars from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) low-resolution spectroscopic data release 9. Based on the equivalent width of the Hα line, we ascertain the activity properties of the stars, identifying a total of 107,134 active stars, with 31,175 exhibiting Hα variations. Furthermore, we establish a positive correlation between starspot activity from Transiting Exoplanet Survey Satellite light curves, and chromospheric activity observed through LAMOST spectra on M dwarf stars. Utilizing LAMOST and Gaia data, we map the two-dimensional distribution of active fractions across all M dwarfs in the Milky Way based on Hα and Hβ lines, confirming a decrease in the active fraction as the distance above the Galactic disk increases. Additionally, we investigate the relationship between chromospheric activity and absolute height above the Galactic disk in various M subtypes. Our findings reveal distinct trends: for M0 to M5 dwarf stars, the active fraction of Hα and Hβ lines rapidly decreases within the 0–300 pc range. In the 300–500 pc range, M0 to M4 dwarf stars exhibit a gradual increase, followed by a decrease in the 500–1000 pc range. Conversely, M5 dwarf stars show no significant gradual increase in the 300–500 pc range and decrease in the 500–1000 pc range. More data will be needed to confirm the phenomenon.

MEASNet. I. A Model for Barium Star Identification and s-process Abundance Estimation from LAMOST DR10 Low-resolution Survey

Barium stars are peculiar stars with enhanced slow neutron capture process (s-process) elements. Abundance analysis of them aids in better understanding the chemical evolution of the Milky Way. In this paper, we introduce a data-driven method named the memory-enhanced adaptive spectral network (MEASNet) to search for barium candidates in the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) low-resolution survey (LRS) and estimate the abundance of five s-process elements: Sr, Y, Ba, Ce, and Nd. MEASNet, trained using spectra from common stars in both LAMOST and the Galactic Archaeology with HERMES survey, showcases notable performance: for the classification task, precision = 98.22% and recall = 94.12%; in prediction, the mean absolute error for the seven elements range between 0.07 and 0.15 dex. After training, we apply the model to 4,083,003 stellar spectra from LAMOST DR10 LRS, successfully identifying 1,803,670 spectra of barium candidates ([Ba/Fe] ≥ 0.25 dex) along with their five s-process elemental abundances. The catalog enlarges the sample size, providing a wealth of data for further statistical analysis of the formation and evolution of barium stars. Meanwhile, this work highlights the potential value of MEASNet in star classification and abundance estimation, offering a strong reference for future data-driven models.

Data-driven Stellar Intrinsic Colors and Dust Reddenings for Spectrophotometric Data: From the Blue-edge Method to a Machine Learning Approach

Intrinsic colors (ICs) of stars are essential for studies on both stellar physics and dust reddening. In this work, we developed an XGBoost model to predict ICs with the atmospheric parameters T eff, logg , and [M/H]. The model was trained and tested for three colors at Gaia and Two Micron All Sky Survey bands with 1,040,446 low-reddening sources. The atmospheric parameters were determined by the Gaia DR3 General Stellar Parameterizer from Photometry (GSP-phot) module and were validated by comparing with the Apache Point Observatory Galactic Evolution Experiment and Large Sky Area Multi-Object fiber Spectroscopic Telescope. We further confirmed that the biases in GSP-phot parameters, especially for [M/H], do not present a significant impact on the IC prediction. The generalization error of the model estimated by the test set is 0.014 mag for (GBP−GRP)0 , 0.050 mag for (GBP−KS)0 , and 0.040 mag for (J−KS)0 . The model was applied to a sample containing 5,714,528 reddened stars with stellar parameters from R. Andrae et al. to calculate ICs and reddenings. The high consistency in the comparison of E(J − K S) between our results and literature values further validates the accuracy of the XGBoost model. The variation of E(G BP − K S)/E(G BP − G RP), a representation of the extinction law, with Galactic longitude is found on large scales. This work preliminarily presents the feasibility and accuracy of the machine learning approach for IC and dust reddening calculation, whose products could be widely applied to spectrophotometric data. The data sets and trained model can be accessed via Zenodo, doi:10.5281/zenodo.12787594. Models for more bands will be completed in following work.