Loss Of Fibers Research Articles

Hundred-meter-scale, kilowatt peak-power, near-diffraction-limited, mid-infrared pulse delivery via the low-loss hollow-core fiber.

We report a high-power single-mode mid-infrared (MIR) pulse delivery system via anti-resonant hollow-core fiber (HCF) with a record delivery distance of 108 m. Near-diffraction-limited MIR light was transmitted by HCFs at wavelengths of 3.12-3.58 µm using a tunable optical parametric oscillator (OPO) as the light source. The HCFs were purged beforehand with argon in order to remove or reduce loss due to parasitic gas absorption (HCl, CO2, etc.). The minimum fiber loss values were 0.05 and 0.24 dB/m at 3.4-3.6 µm and 4.5-4.6 µm, respectively, with the 4.5-4.6 µm loss figure representing, to the best of our knowledge, a new low loss record for a HCF in this spectral region. At a coupling efficiency of ∼70%, average powers of 592 mW and 133 mW were delivered through 5 m and 108 m of HCF, respectively. Assuming the 120-ps duration of the MIR pulses remained constant over the low-dispersion HCF (theoretical maximum: 0.4 ps/nm/km), the corresponding calculated peak powers were 4.9 kW and 1.1 kW.

Detection of the Information Leakage Channel from Multimode Optical Fiber Using a Silicone Photomultiplier

Currently, fiber-optic communication lines are widely used for data transmission. Despite the fact that the information signal propagates inside the optical fiber, covered with a protective shell, there are various ways to form information leakage channels from such fibers. The power control of the information signals transmitted over an optical fiber is one of the most common ways to detect an information leakage channel. This paper determines the parameters of a fiber-optic communication line based on multimode optical fibers for which silicon photomultipliers to detect information leakage channels can be used. The dependences of the branched power on the fiber bending diameter are presented. It has been found that the bending diameter increase leads to the branched power decrease and a decrease in the ability of the photodetector to detect power loss in the optical fiber. The value of the branched power of optical radiation with a wavelength of 850 nm is greater than for 650 nm for all studied bending diameters. It has been established that an increase in the optical radiation power introduced into the fiber to 10 mW makes it possible to detect power loss up to –0.005 dB for an optical radiation wavelength of 850 nm, and –0.142 dB for a wavelength of 650 nm. The results of this article can be used in systems for protecting information transmitted over fiber-optic communication lines.

Simulation and optimization of spectral parameters of resonant optical gyroscope

As a new inertial navigation device, the resonant optical gyroscope offers advantages that include high precision, device integration, impact resistance, and solid-state realization. This device will be widely used in future military and civil applications. Following consideration of the factors that affect accuracy improvement of resonant fiber optic gyroscopes, the relationships among the insertion loss, coupling coefficient, and unit length loss of the cavity fiber and the resonance depth, full width at half maximum, and fineness of the transmission spectrum line are analyzed. To improve the transmission spectrum’s resonance depth, the coupling coefficient should be controlled at 0.2 and the optical coupler insertion loss should be reduced as far as possible. Additionally, the laser linewidth effects on the transmission spectrum and the limit sensitivity are analyzed. It is found that if the laser linewidth of the resonant optical gyroscope is less than 100 kHz, it can meet the resonance depth requirements, thus, providing a technical reference for further research into integrated optical waveguide gyroscopes.

P.61 Imaging Mass Cytometry reveals new clues to understand the pathogenesis of Becker muscular dystrophy

Muscular dystrophies are genetic diseases characterised by muscle fiber loss and its replacement by fibrotic and adipose tissue. Several cell types, including macrophages and fibroadipogenic precursor cells (FAPS) interact with degenerative muscle fibers locally in what is known as the degenerative niche. Recent technological advances known as spatial biology allow dissecting cell-to-cell interactions in vivo using samples of tissue, although this has not been applied to human muscle tissue yet. We analysed muscle biopsies of controls and patients with Becker muscular dystrophy (BMD) at early, moderate and advanced stages of degeneration using Hyperion Imaging Mass Cytometry (IMC). We labelled single sections of the biopsies with 40 markers labelling different components of the muscle structure. We developed a deep learning algorithm to analyse the images and studied changes in the composition and spatial correlations of the different markers across disease progression. We included 2 control and 8 muscle biopsies of BMD. We observed a progressive increase in the amount of collagen-I and III, that significantly correlated with the amount of CD68+ macrophages (R=0.93 and R=0.94), most of them positive for the M2 marker CD206. Fat and collagen I surrounded vessels during the first stages of disease progression, substituting muscle fibres in later stages. We observed a negative correlation between regenerative muscle fibers and collagen-I (R=-0.83) and with CD68 cells (R:-0.90). We also observed a modification in the number of satellite cells in the biopsies across disease progression. IMC enables the study of changes in muscle structure along disease progression in patients with muscular dystrophies establishing spatio-temporal correlations opening the door to confirm and understand new potential pathogenic pathways in vivo in human samples.

Observation of the noise-driven thermalization of the Fermi-Pasta-Ulam-Tsingou recurrence in optical fibers

We report the observation of the thermalization of the Fermi-Pasta-Ulam-Tsingou recurrence process in optical fibers. We show the transition from a reversible regime to an irreversible one, revealing a spectrally thermalized state. To do so, we actively compensate the fiber loss to make the observation of several recurrences possible. We inject into the fiber a combination of three coherent continuous waves, which we call Fourier modes, and a random noise. We enhance the noise-driven modulation instability process against the coherent one by boosting the input noise power level to speed up the evolution to the thermalization. The distributions of the Fourier modes power along the fiber length are recorded thanks to a multi-heterodyne time-domain reflectometer. At low input noise levels, we observe up to four recurrences. Whereas, at higher noise levels, the Fourier modes fade into the noise-driven modulation instability spectrum revealing that the process reached an irreversible thermalized state.

Buckling-induced wavy optical fiber attenuator.

An optical attenuator is an optical device that can modulate the power level of an optical signal. Based on the macro-bending loss of optical fibers, we present a wavy fiber attenuator where the attenuation level can be controlled by a mechanical-induced buckling of the fiber. By bonding a fiber to a prestretched substrate and then releasing the prestrain, the fiber flexes into a sinusoidal wavy curve due to the constraints of the substrate. The level of the light attenuation can simply be controlled by stretching the substrate. The maximum attenuation of the proposed wavy optical fiber attenuator is -87.3 dB.

Case Report: Retinal nerve fiber layer and ganglion cell thinning on spectral domain optical coherence tomography following multiple strokes

A 62-year-old Caucasian male presented for a routine exam with a history of a significant stroke suffered 5 years prior resulting in temporary aphasia and persistent visual field loss. At presentation, best correctable acuities were 20/20+ OU through mild hyperopic astigmatic correction. Visual field testing with frequency doubling technology revealed an incongruous left superior quandrantanopia. Anterior segments demonstrated mild bilateral mixed blepharitis but were otherwise unremarkable. Dilated fundus examination with spectral domain optical coherence tomography revealed moderate disc cupping and marked, symmetric inferior and temporal RNFL thinning, as well as diffuse bilateral ganglion cell thinning. This case demonstrates how OCT can be used as an objective test to detect retrograde neve fiber and ganglion cell loss secondary to post-chiasmal pathology.

Capillary rarefaction during bed rest is proportionally less than fibre atrophy and loss of oxidative capacity.

Muscle disuse from bed rest or spaceflight results in losses in muscle mass, strength and oxidative capacity. Capillary rarefaction may contribute to muscle atrophy and the reduction in oxidative capacity during bed rest. Artificial gravity may attenuate the negative effects of long-term space missions or bed rest. The aim of the present study was to assess (1) the effects of bed rest on muscle fibre size, fibre type composition, capillarization and oxidative capacity in the vastus lateralis and soleus muscles after 6 and 55days of bed rest and (2) the effectiveness of artificial gravity in mitigating bed-rest-induced detriments to these parameters. Nineteen participants were assigned to a control group (control, n=6) or an intervention group undergoing 30min of centrifugation (n=13). All underwent 55days of head-down tilt bed rest. Vastus lateralis and soleus biopsies were taken at baseline and after 6 and 55days of bed rest. Fibre type composition, fibre cross-sectional area, capillarization indices and oxidative capacity were determined. After just 6days of bed rest, fibre atrophy (-23.2±12.4%, P<0.001) and reductions in capillary-to-fibre ratio (C:F; 1.97±0.57 vs. 1.56±0.41, P<0.001) were proportional in both muscles as reflected by a maintained capillary density. Fibre atrophy proceeded at a much slower rate between 6 and 55days of bed rest (-11.6±12.1% of 6days, P=0.032) and was accompanied by a 19.1% reduction in succinate dehydrogenase stain optical density (P<0.001), without any further significant decrements in C:F (1.56±0.41 vs. 1.49±0.37, P=0.459). Consequently, after 55days of bed rest, the capillary supply-oxidative capacity ratio of a fibre had increased by 41.9% (P<0.001), indicating a capillarization in relative excess of oxidative capacity. Even though the heterogeneity of capillary spacing (LogR SD) was increased after 55days by 12.7% (P=0.004), tissue oxygenation at maximal oxygen consumption of the fibres was improved after 55days bed rest. Daily centrifugation failed to blunt the bed-rest-induced reductions in fibre size and oxidative capacity and capillary rarefaction. The relationship between fibre size and oxidative capacity with the capillary supply of a fibre is uncoupled during prolonged bed rest as reflected by a rapid loss of muscle mass and capillaries, followed at later stages by a more than proportional loss of mitochondria without further capillary loss. The resulting excessive capillary supply of the muscle after prolonged bed rest is advantageous for the delivery of substrates needed for subsequent muscle recovery.

KS05.5.A Alterations in white matter fiber density associated with structural MRI and metabolic PET lesions following multimodal therapy in glioma patients

Abstract Background In glioma patients, multimodal therapy and recurrent tumor result in local brain tissue changes, characterized by pathologic findings in structural MRI and metabolic PET images. Little is known about these different lesion types’ impact on the local white matter fiber architecture and clinical outcome. Patients and Methods This study included data from 121 pretreated patients (median age, 52 years; ECOG, 01) with histomolecularly characterized glioma (WHO grade IV glioblastoma, n=81; WHO grade III anaplastic astrocytoma, n=28; WHO grade III anaplastic oligodendroglioma, n=12), who had a resection, radiotherapy, alkylating chemotherapy, or combinations thereof. After a median time of 14 months (range, 1-214 months), post-therapeutic structural and metabolic findings were evaluated using anatomical MRI and O-(2-[18F]fluoroethyl)-L-tyrosine (FET) PET acquired on a 3T hybrid PET/MR scanner. Local fiber density was estimated from tractography based on highangular resolution diffusion-weighted imaging. A cohort of 121 healthy subjects selected from the 1000BRAINS study and matched for age, gender and education served as a control group. Results The median volume of resection cavities, contrast-enhancing regions, regions with pathologically increased FET uptake, and T2/FLAIR hyperintense regions amounted to 20.9, 7.9, 30.3, and 53.4 mL, respectively. Compared to the control group, the average local fiber density in these regions was significantly reduced (p&amp;lt;0.001). Resection cavities showed the highest reduction, followed by contrast-enhancing lesions and metabolically active tumors on FET PET (relative fiber density reduction, -87%, -65%, -55%, respectively). The local fiber density was inversely related (p=0.005) to the FET uptake in recurrent tumors. T2/FLAIR hyperintense lesions, either assigned to peritumoral edema in recurrent glioma or radiation-induced gliosis, had a comparable impact on reducing fiber density (48% and 41%, respectively). The total fiber loss (average fiber loss multiplied by lesion volume) associated with contrast-enhancing lesions (p=0.006) and T2/FLAIR hyperintense lesions (p=0.013) had a significant impact on the general performance status of the patients (ECOG score). Conclusions Our results suggest that apart from resection cavities, reduction in local fiber density is greatest in contrast-enhancing recurrent tumors, but total fiber loss induced by edema or gliosis has an equal detrimental effect on the patients’ performance due to the larger volume affected. Funding Funded by the 1000BRAINS study (INM, Research Centre Juelich, Germany), Horizon 2020 (Grant No. 945539 (HBP SGA3; SC)), and Heinz Nixdorf Foundation.

Graph wavelets for fault localization in optical mesh networks

• Real-time fault detection and localization mechanism in Elastic Optical Networks (EONs). • Alarm correlation strategies fail in the face of static threshold settings. • Detects and localizes silent network failures. • Multi-resolution analysis based on graph wavelets to address fault detection and localization problems. • Exceeds alarm based engines for fault detection and localization accuracy. EONs (Elastic Optical Networks) form the backbone of web-scale cloud infrastructure. These networks should deal with network faults and restoration in real-time with high accuracy and scalability. Thus, fault management functions to detect and localize such failures, play a critical role in modern day EONs. Network impairments are complex in nature in optical networks such as fiber losses, NLI (Non Linear Impairments) and ASE (Amplified Stimulated Emission). Currently, pre-engineered thresholds are used to detect failures in optical networks. Traditional alarm correlation strategies fail in the face of these static threshold settings. In this work, we introduce a real-time fault detection and localization mechanism, which is agnostic to such pre-engineered threshold settings. We apply multi-resolution analysis based on graph wavelets to address fault detection and localization problems. Thus, we propose to use spectrograms and wavelet coefficients to identify the irregularities in an otherwise smooth graph signal. We present a real-time fault localization analysis based on a novel Wavelet Coefficients Trail (WCT) algorithm to root-cause a client signal failure due to OSNR (Optical Signal to Noise Ratio) degradation. We apply the proposed techniques and algorithms to simulated and actual network data. Our results indicate that the proposed methods can root-cause OSNR degradation to major/minor deviations in received power on optical spans. In conclusion, we present a fault localization framework based on graph wavelets in optical mesh networks.

32514 Primary cutaneous marginal zone B-cell lymphoma involution with anetoderma

A 57-year-old gentleman presented with an 8-year history of rash on his trunk and limbs. He initially presented with small erythematous patches, which became plaque-like, violaceous, and resolved over months to years with atrophy. The initial clinical impression was of a cutaneous lymphoma or a lupus-like process. A biopsy showed a leucocytoclastic vasculitis with eosinophils with no epidermotropism or basal exocytosis, and loss of elastic fibres in the upper to mid dermis confirming anetoderma in the resolved sites. Immunostaining demonstrated scattered CD3+ T-cells showing a mix of CD4 and CD8 subtypes. CD20 was negative. Few macrophages were CD60+. T-cell gene rearrangement testing was inconclusive. A mildly positive anticardiolipin antibody (10.7, range 0-10) was noted. An inflammatory anetoderma secondary to antiphospholipid syndrome was suspected. Aspirin and warfarin therapy trial showed no benefit. As his rash was stable, he was discharged, but presented 3 years later with a significant flare. On examination he had raised, violaceous and indurated plaques across his trunk. Anetoderma was noted where the rash had resolved. A skin biopsy showed an atypical lymphoid infiltrate consisting of prominent lymphoplasmacytoid cells with lambda-light-chain restriction consistent with a primary cutaneous marginal zone B cell lymphoma (PCMZL). PCMZL is a form of cutaneous B-cell lymphoma which follows an indolent course. Patients may have solitary skin lesions or present with multiple papulonodular lesions, as in our case. Involution of lesions of PCMZL with secondary anetoderma has been previously described. We present this case of PCMZL involuting with anetoderma to highlight this rare presentation.

32514 Primary cutaneous marginal zone B-cell lymphoma involution with anetoderma

A 57-year-old man presented with an 8-year history of rash on his trunk and limbs. He initially presented with small erythematous patches, which became plaque-like, violaceous, and resolved over months to years with atrophy. The initial clinical impression was of a cutaneous lymphoma or a lupus-like process. A biopsy showed a leucocytoclastic vasculitis with eosinophils with no epidermotropism or basal exocytosis, and loss of elastic fibres in the upper to mid dermis confirming anetoderma in the resolved sites. Immunostaining demonstrated scattered CD3+ T-cells showing a mix of CD4 and CD8 subtypes. CD20 was negative. Few macrophages were CD60+. T-cell gene rearrangement testing was inconclusive. A mildly positive anticardiolipin antibody (10.7, range 0-10) was noted. An inflammatory anetoderma secondary to antiphospholipid syndrome was suspected. Aspirin and warfarin therapy trial showed no benefit. As his rash was stable, he was discharged, but presented 3 years later with a significant flare. On examination he had raised, violaceous and indurated plaques across his trunk. Anetoderma was noted where the rash had resolved. A skin biopsy showed an atypical lymphoid infiltrate consisting of prominent lymphoplasmacytoid cells with lambda-light-chain restriction consistent with a primary cutaneous marginal zone B-cell lymphoma (PCMZL). PCMZL is a form of cutaneous B-cell lymphoma which follows an indolent course. Patients may have solitary skin lesions or present with multiple papulonodular lesions, as in our case. Involution of lesions of PCMZL with secondary anetoderma has been previously described. We present this case of PCMZL involuting with anetoderma to highlight this rare presentation.

Sudomotor dysfunction and corneal nerve loss: An unusual presentation of syringomyelia and COVID-19 infection

Aim: To highlight unusual neurological findings in a patient with syringomyelia and COVID-19. Methods: Neurological examination, Vibration Perception Threshold (VPT), Magnetic Resonance Imaging (MRI) of the full neuroaxis, electrophysiologic studies, Corneal Confocal Microscopy (CCM) and Sudoscan were performed. Results: A previously fit and well 28-year-old lady presented with worsening shoulder and neck pain after COVID-19. She was found to have reduced pinprick sensation in both arms and base of the neck and MRI revealed a cervical syrinx. Electrophysiologic studies showed no evidence of upper limb neuropathy or cervical radiculopathy, but CCM showed corneal nerve loss and Sudoscan demonstrated severe sudomotor dysfunction in both hands. Conclusion: We present an unusual case of worsening pain with sudomotor dysfunction and corneal nerve fibre loss in a patient with syringomyelia and COVID-19 infection.

Antisense Morpholino-Based In Vitro Correction of a Pseudoexon-Generating Variant in the SGCB Gene.

Limb-girdle muscular dystrophies (LGMD) are clinically and genetically heterogenous presentations displaying predominantly proximal muscle weakness due to the loss of skeletal muscle fibers. Beta-sarcoglycanopathy (LGMDR4) results from biallelic molecular defects in SGCB and features pediatric onset with limb-girdle involvement, often complicated by respiratory and heart dysfunction. Here we describe a patient who presented at the age of 12 years reporting high creatine kinase levels and onset of cramps after strenuous exercise. Instrumental investigations, including a muscle biopsy, pointed towards a diagnosis of beta-sarcoglycanopathy. NGS panel sequencing identified two variants in the SGCB gene, one of which (c.243+1548T>C) was found to promote the inclusion of a pseudoexon between exons 2 and 3 in the SGCB transcript. Interestingly, we detected the same genotype in a previously reported LGMDR4 patient, deceased more than twenty years ago, who had escaped molecular diagnosis so far. After the delivery of morpholino oligomers targeting the pseudoexon in patient-specific induced pluripotent stem cells, we observed the correction of the physiological splicing and partial restoration of protein levels. Our findings prompt the analysis of the c.243+1548T>C variant in suspected LGMDR4 patients, especially those harbouring monoallelic SGCB variants, and provide a further example of the efficacy of antisense technology for the correction of molecular defects resulting in splicing abnormalities.

Distributed birefringence sensing at 10-9 accuracy over ultra-long PMF by optical frequency comb and distributed Brillouin amplifier.

Brillouin dynamic gratings (BDG) can measure the distributed birefringence of polarization-maintaining fibers (PMF), however, its sensing range is limited by both stimulated Brillouin scattering depletion and fiber losses in PMF, which are significantly higher than those in standard single-mode fibers. In this work, we theoretically and experimentally verify that BDG can be sustained over ultra-long distances when assisted by distributed Brillouin amplification, significantly extending the distributed birefringence measurement distance. Using an optical frequency comb pumped by a narrow linewidth laser to both generate and interrogate the amplified BDG, a birefringence measurement accuracy of 7.5 × 10-9 was achieved over 7 km sensing length, more than double the longest range reported. This opens a new opportunity to investigate small birefringence changes due to nonlinear optics effects and monitoring fiber network security from eavesdropping.

Antagonism of the Muscarinic Acetylcholine Type 1 Receptor Enhances Mitochondrial Membrane Potential and Expression of Respiratory Chain Components via AMPK in Human Neuroblastoma SH-SY5Y Cells and Primary Neurons

Impairments in mitochondrial physiology play a role in the progression of multiple neurodegenerative conditions, including peripheral neuropathy in diabetes. Blockade of muscarinic acetylcholine type 1 receptor (M1R) with specific/selective antagonists prevented mitochondrial dysfunction and reversed nerve degeneration in in vitro and in vivo models of peripheral neuropathy. Specifically, in type 1 and type 2 models of diabetes, inhibition of M1R using pirenzepine or muscarinic toxin 7 (MT7) induced AMP-activated protein kinase (AMPK) activity in dorsal root ganglia (DRG) and prevented sensory abnormalities and distal nerve fiber loss. The human neuroblastoma SH-SY5Y cell line has been extensively used as an in vitro model system to study mechanisms of neurodegeneration in DRG neurons and other neuronal sub-types. Here, we tested the hypothesis that pirenzepine or MT7 enhance AMPK activity and via this pathway augment mitochondrial function in SH-SY5Y cells. M1R expression was confirmed by utilizing a fluorescent dye, ATTO590-labeled MT7, that exhibits great specificity for this receptor. M1R antagonist treatment in SH-SY5Y culture increased AMPK phosphorylation and mitochondrial protein expression (OXPHOS). Mitochondrial membrane potential (MMP) was augmented in pirenzepine and MT7 treated cultured SH-SY5Y cells and DRG neurons. Compound C or AMPK-specific siRNA suppressed pirenzepine or MT7-induced elevation of OXPHOS expression and MMP. Moreover, muscarinic antagonists induced hyperpolarization by activating the M-current and, thus, suppressed neuronal excitability. These results reveal that negative regulation of this M1R-dependent pathway could represent a potential therapeutic target to elevate AMPK activity, enhance mitochondrial function, suppress neuropathic pain, and enhance nerve repair in peripheral neuropathy.

Early Diagnosis in Cerebellar Ataxia, Neuropathy, Vestibular Areflexia Syndrome (CANVAS) by Focusing on Major Clinical Clues: Beyond Ataxia and Vestibular Impairment.

CANVAS, a rare disorder responsible for late-onset ataxia of autosomal recessive inheritance, can be misdiagnosed. We investigated a series of eight patients with sensory neuropathy and/or an unexplained cough, who appeared to suffer from CANVAS, and we emphasized the clinical clues for early diagnosis. Investigations included clinical and routine laboratory analyses, skin biopsy, nerve biopsy and molecular genetics. The eight patients had clinical and/or laboratory evidence of sensory neuronopathy. All but one had neuropathic pain that had started in an asymmetric fashion in two patients. A chronic cough was a prominent feature in our eight patients and had started years before neuropathic symptoms in all but one. The course of the disease was slow, and ataxia remained mild in all. Five patients were initially thought to have immune-mediated sensory neuronopathy and received immunotherapy. Skin biopsies showed a near complete and non-length-dependent loss of intraepidermal nerve fibers. Moreover, nerve biopsy findings suggested a prominent involvement of small myelinated and unmyelinated fibers. The burden of CANVAS extends far beyond cerebellar ataxia and vestibular manifestations. Indeed, our study shows that a chronic cough and neuropathic pain may represent a major source of impairment in these patients and should not be overlooked to allow an early diagnosis and prevent unnecessary immunotherapy.

Relationship between time in range and corneal nerve fiber loss in asymptomatic patients with type 2 diabetes.

Corneal confocal microscopy (CCM) is a noninvasive technique to detect early nerve damage of diabetic sensorimotor polyneuropathy (DSPN). Time in range (TIR) is an emerging metric of glycemic control which was reported to be associated with diabetic complications. We sought to explore the relationship between TIR and corneal nerve parameters in asymptomatic patients with type 2 diabetes (T2DM). In this cross-sectional study, 206 asymptomatic inpatients with T2DM were recruited. After 7 days of continuous glucose monitoring, the TIR was calculated as the percentage of time in the glucose range of 3.9 to 10.0 mmol/L. CCM was performed to determine corneal nerve fiber density, corneal nerve branch density, and corneal nerve fiber length (CNFL). Abnormal CNFL was defined as ≤15.30 mm/mm 2 . Abnormal CNFL was found in 30.6% (63/206) of asymptomatic subjects. Linear regression analyses revealed that TIR was positively correlated with CCM parameters both in the crude and adjusted models (all P < 0.05). Each 10% increase in TIR was associated with a 28.2% (95% CI: 0.595-0.866, P = 0.001) decreased risk of abnormal CNFL after adjusting for covariates. With the increase of TIR quartiles, corneal nerve fiber parameters increased significantly (all P for trend <0.01). The receiver operating characteristic curve indicated that the optimal cutoff point of TIR was 77.5% for predicting abnormal CNFL in asymptomatic patients. There is a significant independent correlation between TIR and corneal nerve fiber loss in asymptomatic T2DM patients. TIR may be a useful surrogate marker for early diagnosis of DSPN.

SEPT9 Upregulation in Satellite Glial Cells Associated with Diabetic Polyneuropathy in a Type 2 Diabetes-like Rat Model.

Despite the worldwide prevalence and severe complications of type 2 diabetes mellitus (T2DM), the pathophysiological mechanisms underlying the development of diabetic polyneuropathy (DPN) are poorly understood. Beyond strict control of glucose levels, clinical trials for reversing DPN have largely failed. Therefore, understanding the pathophysiological and molecular mechanisms underlying DPN is crucial. Accordingly, this study explored biochemical and neuropathological deficits in a rat model of T2DM induced through high-fat diet (HFD) feeding along with two low-dose streptozotocin (STZ) injections; the deficits were explored through serum lipid, neurobehavioral, neurophysiology, neuropathology, and immunohistochemistry examinations. Our HFD/STZ protocol induced (1) mechanical hyperalgesia and depression-like behaviors, (2) loss of intraepidermal nerve fibers (IENFs) and reduced axonal diameters in sural nerves, and (3) decreased compound muscle action potential. In addition to hyperglycemia, which was correlated with the degree of mechanical hyperalgesia and loss of IENFs, we observed that hypertriglyceridemia was the most dominant deficit in the lipid profiles of the diabetic rats. In particular, SEPT9, the fourth component of the cytoskeleton, increased in the satellite glial cells (SGCs) of the dorsal root ganglia (DRG) in the T2DM-like rats. The number of SEPT9(+) SGCs/DRG was correlated with serum glucose levels and mechanical thresholds. Our findings indicate the putative molecular mechanism underlying DPN, which presumably involves the interaction of SGCs and DRG neurons; nevertheless, further functional research is warranted to clarify the role of SEPT9 in DPN.

Experimental demonstration of single-span 100-km O-band 4×50-Gb/s CWDM direct-detection transmission.

We report on what is to the best of our knowledge the longest 50-Gb/s/λ O-band wavelength-division multiplexed (WDM) transmission. A pair of in-house built bismuth-doped fiber amplifiers (BDFAs) and the use of Kramers-Kronig detection-assisted single-sideband transmission are adopted to overcome the fiber loss and chromatic dispersion, respectively, in a reach-extended O-band coarse WDM (CWDM) system with a channel spacing of ∼10 nm. Through experiments on an amplified 4×50-Gb/s/λ direct-detection system based on booster and pre-amp BDFAs, we show the superior performance of single-sideband transmission in terms of both optical signal-to-noise ratio sensitivity and uniformity in performance amongst CWDM channels relative to double-sideband transmission after both 75-km and 100-km lengths of single-mode fiber. As a result, up to 100-km reach with comparable performance at all 50-Gb/s channels was achieved without the need for in-line optical amplification.