Total Fiber Length Research Articles

Investigation of the Relationship of Sleep Disorder Occurring in Fibromyalgia with Central Nervous System and Pineal Gland Volume

Abstract Objective: Mechanisms of sleep disorders in fibromyalgia (FM) patients, such as insomnia, early morning awakenings and poor quality sleep, have not yet been proven and no consistent and effective treatment is yet available. The aim of this study was to investigate the pineal gland volume and the relationship between total fiber count, total fiber volume and total fiber length of the spinoreticular tract involved in regulation of sleep and wakefulness in terms of the mechanism of sleep disturbance. Methods: This study included only female cases, 31 with fibromyalgia and 31 controls. Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality. Tractography of targeted pathway from brain diffusion MR images was calculated in DSI Studio program and the volume of the pineal gland was calculated in ITK-SNAP program. Results: The mean volume of the pineal gland was higher in control group (218.84±64.45 mm3) than in fibromyalgia group (174.77±48.65 mm3), which was statistically significant (p=0.004). However, there was no statistically significant difference between two groups in total spinoreticular tract (TSRT), total volume (TSRTV), TSRT FA, TSRT MD, TSRT AD and TSRT RD of spinoreticular tract, which is involved in the regulation of sleep and wakefulness (p>0.05). Conclusion: In conclusion, it is thought that the endocrine system may be more related to sleep disturbance in individuals with FM than central nervous system. Therefore, we believe that it may be more appropriate to work on the endocrine system rather than neural system in the treatment of sleep disturbance in patients with FM.

Investigating the Impact of Topology and Physical Impairments on the Capacity of an Optical Backbone Network

Optical backbone networks constitute the fundamental infrastructure employed today by network operators to deliver services to users. As network capacity is a key factor influencing optical network performance, it is important to understand how topological and physical properties impact its behavior and to have the capability to estimate its value. In this context, we propose here a method to evaluate the network capacity that relies on the optical reach to account for physical layer aspects in conjunction with constrained routing techniques for traffic routing. As this type of routing can lead to traffic blocking, particularly due to the limitation on the number of wavelengths per fiber, we also propose a fiber assignment algorithm designed to deal with this problem. We apply this method to a set of randomly generated networks using a modified Waxman model, and for a network with 60 nodes, in a scenario without blocking, we obtain capacities of about 2.5 Pbit/s for a symbol rate of 64 Gbaud and about 5 Pbit/s for a symbol rate of 128 Gbaud. Remarkably, this duplication in the total network capacity is achieved by an increase in the total fiber length of only about 51%.

Development of new surgical mesh geometries with different mechanical properties using the design freedom of 3D printing

AbstractThe emergence of new rapid prototyping techniques such as melt electrowriting and their application in the development of medical devices, enables new geometries for surgical meshes that were previously limited by current conventional manufacturing methods. The change in geometry allows a direct impact on the mechanical behavior of surgical meshes using identical polymers. The adaptation of the mechanical properties of surgical meshes, based on sinusoidal auxetic design with varying amplitude and number of waves per total fiber length, aims to improve biocompatibility by mimicking and matching the mechanical properties of vaginal soft tissue, which is not provided by current polypropylene nondegradable meshes. The auxetic design of the meshes can supply dimensionally stable pores under tensile load, which is a limitation of the current meshes. The mechanical properties can be controlled with mesh deformations up to 100%, Young's modulus ranging from 50 to 400 N/mm2 and a variable toe region. The printed meshes show an effective porosity of over 70% and are lightweight or ultra‐lightweight. By combining matching mechanical properties with good porosity and weight, 3D printed sinusoidal meshes, made of biodegradable Poly‐ε‐caprolactone, show promising results to improve surgical meshes for use in pelvic organ prolapse repair.

Study Explores Integration of Subsea Optical Distribution Systems

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 32645, “All-Optical Subsea Sensing and Communications,” by Glenn Wilson, SPE, Halliburton, and Mauricio Uribe and Sigurd Moe, TechnipFMC, et al. The paper has not been peer reviewed. Copyright 2023 Offshore Technology Conference. Reproduced by permission. _ Subsea control systems use electric or optical communication channels within subsea optical distribution systems for redundant, duplex telemetry between topside facilities and subsea control systems. Downhole fiber-optic sensing (DFOS) systems use the same subsea optical distribution systems for establishing transmission paths between the same topside facilities and downhole sensing fibers. At the time of writing, subsea fiber-optic control and sensing systems have been operated on independent subsea optical distribution systems. This redundancy introduces complexity and cost into the overall subsea optical distribution system required for subsea developments. In the complete paper, the authors describe the systems that combine fiber-optic communications for subsea control systems and DFOS systems into the same subsea optical distribution system. Need for Systems Integration While maturity of, and demand for, DFOS technology has grown for offshore projects with dry-tree installations, operators have expressed the need for solutions to address fiber-optic technology gaps for subsea development projects. To this end, the topside DFOS interrogation of subsea wells requires optical engineering solutions to compensate for the insertion losses and back-reflections accumulated through umbilicals, multiple wet- and dry-mate optical connectors, splices, optical feedthrough systems (OFS), and downhole-sensing-fiber and optical wet-mate connectors (Fig. 1). To obviate these problems for distributed acoustic sensing (DAS), the authors previously introduced a subsea fiber topology with two transmission fibers from the topside to a remote optical circulator deployed in the optical flying lead (OFL) at the subsea tree. This limits the sensing fiber portion of the total fiber length to the fiber located below the remote circulator and eliminates all back-reflections from the multiple subsea connectors in the subsea infrastructure above the remote circulator. The DAS pulse-repetition rate is constrained only by the fiber length below the remote circulator, thus enabling dry-tree equivalent pulse-repetition rates (i.e., acoustic bandwidth) regardless of the tieback distance. This yields significant signal-to-noise ratio improvement through stacking and selective amplification while further enabling sensing of high-frequency acoustic events occurring inside, or in the vicinity of, the wellbore. The initial application for subsea DAS was installing fiber from the tubing hanger to the production packer for vertical seismic profiling. The ability to maximize acoustic bandwidth irrespective of tieback distance, however, enables a wider range of interventionless reservoir diagnostic applications. This has increased operator demand for installing fiber across the reservoir section.

Changes in myelinated fibers in the hippocampus of streptozotocin-induced diabetic rats: a stereological investigation.

Diabetes causes cognitive impairment, and the hippocampus is important for long-term and permanent memory function. However, the mechanism of their interaction is still unclear. In this study, rat models of diabetes mellitus were generated by a single injection of streptozotocin (STZ). This study aims to explore the changes in myelinated fibers in the hippocampus of type 1 diabetic rats. The unbiased stereological methods and transmission electron microscopy were used to obtain the total volume of the hippocampus, the total volume of the myelin sheath, the total length of the myelinated nerve fibers, the distribution of the length with different diameters of the myelinated fibers, and the distribution of the length with different thickness of the myelin sheath. Stereological analysis revealed that, compared to that of the control group, the total myelinated fibers volumes and the total myelinated fibers length were decreased slightly, while the total volume and the thickness of myelin sheaths were significantly decreased in the diabetic group. Finally, when compared with the control group, the total length of myelinated fibers in the diabetes group was significantly reduced, with diameters ranging from 0.7 to 1.1 μm and thicknesses of myelin sheaths from 0.15 to 0.17 μm. This study provides the first experimental evidence by stereological means to demonstrate that myelinated nerve fibers may be the key factor in cognitive dysfunction in diabetes.

FiWi network planning for WiFi enabled gram panchayats of India: A frame work using component placement optimization

Fiber Wireless (FiWi) access network consists of high speed passive optical network (PON) at back end and wireless mesh network at front end. It is emerging as the most prominent access network due to its inherent feature. It may provide fast Internet services at minimum possible cost. Many of the villages of the India are still not connected with high speed network hence the present paper provides FiWi network planning for creating the Wireless Fidelity (WiFi) enabled villages (Gram Panchayats) of India. The main aim of the paper is to deploy the cost effective FiWi network to provide the faster internet services at reasonable prices to the users of the gram panchayat (GP) in India. The area of the GP and the user’s location in particular GP is taken as input for network planning. The proposed planning provides the optimized position of wireless routers and Optical Network Units (ONUs) in terms of latitude and longitude. For optimizing position of wireless router and ONUs, we propose to use customized Slime Mould algorithm (SMA). We considered four gram panchayats of Indore region of India to make them WiFi enabled using FiWi access network. The customized SMA algorithm provides the best possible position and number of wireless routers and ONUs to connect all the users of gram panchayat. Beside, the total fiber length from the Optical Line Terminal (OLT) to all the ONUs and total cost estimation is also given to create the complete network.

Compression of Fibrous Assemblies: Revisiting the Stress–Density Relation

Abstract Many engineering materials are made from fibers, and fibrous assemblies are often compacted during the fabrication process. Compression leads to the formation of contacts between fibers, and this causes stiffening. The relation between the uniaxial stress, S, and the volume fraction of fibers, φ, is of power law form. The derivation of this relation based on micromechanics considerations takes as input the structural evolution represented by the dependence of the mean segment length of the network, lc, on the current density, ρ (ρ is defined as the total length of fiber per unit volume of the network). In this work, we revisit this problem while considering that the mean segment length should be defined exclusively by fiber contacts that transmit load. We use numerical simulations of the compression of crimped fiber assemblies to show that, when using this definition, ρ∼1/lc2 at large enough strains. Purely geometric considerations require that ρ∼1/lc, and we observe that this applies in the early stages of compaction. In pre-stressed networks, the density–mean segment length scaling is of the form ρ∼1/lc2 at all strains. This has implications for the relation between stress and the fiber volume fraction. For both ρ versus lc scalings, S∼(φn−φ0n), where φ0 is the initial or reference fiber volume fraction; however, n = 3 when ρ∼1/lc and n = 2 for ρ∼1/lc2. These predictions are compared with experimental data from the literature.

Generation of High Power Ultrashort Pulses in Tapered Yb-Doped PCF Through Self-Similar Compression

We present a numerical approach for analysing simultaneous amplification and compression of a chirped hyperbolic secant soliton using a tapered Yb-doped photonic crystal fiber (PCF) based self-similar compressor. Theoretical studies reveal the conservation of input soliton during the amplification process due to self-similar property, which in turn helps for high quality compression of amplified soliton. In order to satisfy the self-similar condition, we note that the Yb-doped fiber should exhibit a decreasing group velocity dispersion (GVD). Such a constraint is met using a tapered PCF in our work, which is modeled using a fully vectorial effective index method (FVEIM). Influence of spatial and spectral dependent gain, saturation energy, amplified spontaneous emission (ASE), dispersion and nonlinearity on pulse propagation are analyzed using the combined solution of dynamic rate equations (DRE) and the generalized nonlinear Schrödinger equation (GNLSE). Numerical outcomes upon solving the aforementioned equations show that a 1 ps pulse is compressed down to a pulsewidth of 55.4 fs with a peak power of 1.03 kW in a total fiber length of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$L=2.5$ </tex-math></inline-formula> m and taper ratio of 2.34. Overall quality of the compression scheme is evidenced by a relatively high compression factor (F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>c</i></sub> ) = 18.12, and low percentage of pedestal energy ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$PE$ </tex-math></inline-formula> ) = 10.95 %

Combined impact of SRS, FWM and ASE noise in UDWDM/DWDM long-haul communication systems using EDFAs

In this paper, the combined impact of SRS, FWM and ASE noise in center channels of 7-, 15-, 31- and 63-channel UDWDM/DWDM long-haul multi-span optical fiber communication systems using different numbers of EDFAs has been analyzed with simulations. UDWDM/DWDM systems with varying system parameters, i.e. channel input powers, channel spacing values, multi-span fiber lengths and numbers of EDFAs, have been taken into account in simulations. Comparative OSNR simulation results satisfying a minimum 23 dB OSNR criterion under the combined impact of SRS, FWM and ASE noise have been presented and evaluated. OSNR vs channel input power simulation results show that FWM becomes the most dominant effect with respect to SRS and ASE noise in UDWDM systems. Therefore, OSNR values decrease as channel input powers increase in multi-span UDWDM systems having 3.125 GHz and 6.25 GHz channel spacing values. However, both ASE noise and SRS become more dominant with respect to FWM in DWDM systems with 100 GHz channel spacing values. OSNR values increase as the channel input powers increase in those multi-span DWDM systems. Simulation results for OSNR vs channel spacing values show that OSNR values obtained in multi-span UDWDM systems increase as channel spacing values increase in the 3.125 GHz–6.25 GHz range. This is due to the decrease in FWM crosstalk, which has a dominant effect in UDWDM systems, with increasing channel spacing values in those UDWDM systems. However, OSNR values obtained in multi-span DWDM systems decrease as channel spacing values increase in the 12.5 GHz–100 GHz range. This is due to the increase in ASE noise, which has a dominant effect in DWDM systems, with increasing optical filter bandwidths of those DWDM systems. OSNR vs channel length simulation results show that OSNR values generally decrease with increasing total fiber lengths and inter-amplifier fiber lengths in both UDWDM and DWDM multi-span systems. This is due to the FWM crosstalk and the ASE noise, which become more dominant with respect to the SRS as the total fiber length and inter-amplifier fiber lengths increase. Simulation results for OSNR vs number of EDFAs show that OSNR values obtained in multi-span UDWDM systems having 3.125 GHz channel spacing values decrease with increasing numbers of EDFAs. However, OSNR values in multi-span UDWDM/DWDM systems having 6.25 GHz-100 GHz channel spacing range increase with increasing numbers of EDFAs. Simulation results provide important clues for the design and implementation of reliable long-haul UDWDM/DWDM systems.

Stress-induced myelin damage in the hippocampal formation in a rat model of depression

BackgroundAccording to previous studies, myelin damage may be involved in the occurrence of depression. However, to date, no study has quantitatively investigated the changes in myelinated fibers and myelin sheaths in the hippocampal formation (HF) and hippocampal subfields in the context of depression. Methods: Male Sprague-Dawley (SD) rats (aged 4–5 weeks) were evenly divided into the control group and chronic unpredictable stress (CUS) group. Behavioral tests were performed, and then changes in myelinated fibers and myelin ultrastructure in hippocampal subfields in depression model rats were investigated using modern stereological methods and transmission electron microscopy techniques. Results: After a four-week CUS protocol, CUS rats showed depressive-like and anxiety-like behaviors. The total length and total volume of myelinated fibers were reduced in the CA1 region and DG in the CUS group compared with the control group. The total volumes of myelin sheaths and axons in the CA1 region but not in the DG were significantly lower in the CUS group than in the control group. The decrease in the total length of myelinated nerve fibers in the CA1 region in CUS rats was mainly due to a decrease in the length of myelinated fibers with a myelin sheath thickness of 0.15 μm–0.20 μm. Limitations: The exact relationship between the degeneration of myelin sheaths and depression-like, anxiety-like behaviors needs to be further investigated. Conclusions: CUS induces depression- and anxiety-like behaviors, and the demyelination in the CA1 region induced by 4 weeks of CUS might be an important structural basis for these behaviors.

Biomarkers of in vivo limbal stem cell function

PurposeTo evaluate in vivo parameters as biomarkers of limbal stem cell function and to establish an objective system that detects and stage limbal stem cell deficiency (LSCD). MethodsA total of 126 patients (172 eyes) with LSCD and 67 normal subjects (99 eyes) were included in this observational cross-sectional comparative study. Slit-lamp biomicroscopy, in vivo laser scanning confocal microscopy (IVCM), and anterior segment optical coherence tomography (AS-OCT) were performed to obtain the following: clinical score, cell morphology score, basal cell density (BCD), central corneal epithelial thickness (CET), limbal epithelial thickness (LET), total corneal nerve fiber length (CNFL), corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), and tortuosity coefficient. Their potential correlations with the severity of LSCD were investigated, and cutoff values were determined. ResultsAn increase clinical score correlated with a decrease in central cornea BCD, limbal BCD, CET, mean LET, maximum LET, CNFL, CNFD, CNBD, and tortuosity coefficient. Regression analyses showed that central cornea BCD, CET and CNFL were the best parameters to differentiate LSCD from normal eyes (Coef = 3.123, 3.379, and 2.223; all p < 0.05). The rank correlation analysis showed a similar outcome between the clinical scores and the central cornea BCD (ρ = 0.79), CET (ρ = 0.82), and CNFL (ρ = 0.71). A comprehensive LSCD grading formula based on a combination of these parameters was established. ConclusionsA comprehensive staging system combining clinical presentation, central cornea BCD, CET, and CNFL is established to accurately and objectively diagnose LSCD and stage its severity.

Low pedestal sub-17 fs pulse generation through cascaded self-similar compression in photonic crystal fibers

We propose a realistic numerical model based on cascaded self-similar pulse compression to generate low pedestal ultrashort pulses at 2.5 µm. Self-similarity in photonic crystal fibers (PCFs) has been attained by modelling exponentially dispersion decreasing and exponentially nonlinearity increasing chalcogenide PCFs. The tapered PCF (TPCF) model is theoretically designed using the fully vectorial effective index method (FVEIM) to obtain accurate effective refractive index, group velocity dispersion (GVD), and Kerr nonlinearity values with low computation time. Initially, fundamental soliton compression in As2S3 tapered PCF is being investigated for the pedestal-free reduction of the pulse width. Subsequently, the compression factor is further enhanced in the As2Se3 PCF-based nonlinear optical loop mirror. The numerical outcomes reveal a compression of 1 ps pulse down to a pulse width of 16.6 fs with a peak power of 116 W in a total fiber length of L = 61 cm.

Network Design for Bus-Type Optical Access Using Distributed Raman Amplification With Asymmetric Power Splitter

This paper proposes loss budget improvement of the bus-type optical access network (NW) with cost-effective non-repeater configuration. To achieve drastic improvements, we propose two approaches; (i) application of a low noise distributed Raman amplification (DRA) technique to upstream signal transmission (ii) utilization of asymmetric power splitters at each drop point to enhance Raman gain and to suppress transmission loss of far branches. We optimize the asymmetric power splitter drop ratio to maximize the number of accommodated users. Then, we clarify the number of accommodated users and improvements based on DRA through calculations that examine the inter-drop distance and total branch number. Experiments evaluate the bit error rate performance of the proposal. We confirm that measured values correspond to the simulation results. Based on the simulation and the experiment, we clarify the optimal network configuration for the user distribution. It is found that bus-type NWs support more accommodated users with shorter total fiber length than star-type NWs for user range examined. The potential advantage of bus-type NWs is revealed.

Behaviour of expanded slate semi-lightweight SCC beams with improved cracking performance and shear capacity

This study investigated the behavior of semi-lightweight self-consolidating concrete (SLWSCC) and lightweight vibrated concrete (LWVC) beams developed with improved shear capacity and cracking behavior. Fourteen concrete beams were cast with different types of lightweight aggregates (either fine or coarse expanded slate aggregates), total binder contents (550 kg/m3 and 600 kg/m3), fiber lengths (8 mm and 12 mm), and different fiber volume fractions (0.3%, 0.5%, and 1%). The experimental results were also compared with several code-based equations and selected proposed models from the literature that predict the shear strength of reinforced concrete beams with and without fibers. The inclusion of shorter polyvinyl alcohol (PVA) fibers appeared to have more influence on improving the shear performance and cracking behavior of SLWSCC beams compared to longer fibers. It was also found that using expanded slate fine aggregate exhibited better results in terms of the beams’ load-carrying capacity, post-diagonal cracking resistance, and energy absorption capacity compared to using expanded slate coarse aggregate. The highest increases in the shear capacity, deformation capacity, post-diagonal cracking resistance, and energy absorption capacity were observed in LWVC beams, as it was possible to use a higher percentage of PVA fibers (1%) because of the absence of self-compactability restrictions.

Anomalous mechanics of Zn2+-modified fibrin networks

Fibrin is the main component of blood clots. The mechanical properties of fibrin are therefore of critical importance in successful hemostasis. One of the divalent cations released by platelets during hemostasis is Zn2+; however, its effect on the network structure of fibrin gels and on the resultant mechanical properties remains poorly understood. Here, by combining mechanical measurements with three-dimensional confocal microscopy imaging, we show that Zn2+ can tune the fibrin network structure and alter its mechanical properties. In the presence of Zn2+, fibrin protofibrils form large bundles that cause a coarsening of the fibrin network due to an increase in fiber diameter and reduction of the total fiber length. We further show that the protofibrils in these bundles are loosely coupled to one another, which results in a decrease of the elastic modulus with increasing Zn2+ concentrations. We explore the elastic properties of these networks at both low and high stress: At low stress, the elasticity originates from pulling the thermal slack out of the network, and this is consistent with the thermal bending of the fibers. By contrast, at high stress, the elasticity exhibits a common master curve consistent with the stretching of individual protofibrils. These results show that the mechanics of a fibrin network are closely correlated with its microscopic structure and inform our understanding of the structure and physical mechanisms leading to defective or excessive clot stiffness.

Effect of Nitrogen Fertilizer Rates and Plant Density on Straw, Fiber Yield and Anatomical Manifestations of Some Flax Cultivars

Two field experiments were carried out at the Experimental Farm at Gemmeiza Agriculture Research Station, Agricultural Research Center, Egypt, during two successive winter growing seasons of 2018/2019 and 2019/2020 to study the response of three flax cultivars, i.e. Sakha 3, Giza 11 and Giza 12 to three nitrogen fertilizer rates (30, 50 and 70 kg N/fed) and three plant densities (1500, 2000 and 2500 seeds/m2) and their effect on straw and fiber yield and its related traits as well as anatomical manifestations for flax stem at middle region. The experimental design was laid out using split-split plot design in four replications. Flax cultivars were distributed in the main plots, whereas nitrogen fertilizer rates were arranged at random in sub-plots and plant densities treatments were assigned at random in sub-sub plots. The sub-sub plot area was 9 m2. Sakha 3 cultivar significantly produced the maximum total plant height, technical stem length, total fiber percentage, fiber yield/plant, fiber yield/fed, fiber length and fiber fineness in both seasons. Meanwhile, the highest No. of basal branches/plant, straw yield/plant and straw yield/fed in both seasons were recorded with Giza 12 cultivar. Meanwhile, Giza 11 cultivar gave the thickness stem diameter in both seasons. Increasing nitrogen fertilizer rates from 30 to 70 kg N/fed caused significant increases in all straw and fiber yield and its related traits of flax, except fiber fineness was significantly decreased with increasing nitrogen rates in both seasons. Increasing plant densities from 1500 to 2500 seeds/m2 caused markedly increment in total plant height, technical stem length, straw yield/fed, total fiber percentage, fiber yield/fed, fiber length and fiber fineness during both seasons. On the other hand, No. of basal branches/plant, stem diameter, straw yield/plant and fiber yield/plant were significantly decreased by increasing plant densities during both seasons. The first order interactions between treatments Sakha 3 X 70 kg N/fed, Sakha 3 X 2500 seeds/m2 and 70 kg N/fed X 2500 seeds/m2 as well as the second order interaction between treatments Sakha 3 X 70 kg N/fed X 2500 seeds/m2 were significantly recorded the highest total plant height, technical stem length, fiber yield/fed and fiber length as compared with the others interactions in both seasons. While, the maximum fiber yield/fed were recorded from the first order interactions between treatments Sakha 3 X 70 kg N/fed, Sakha 3 X 2500 seeds/m2 and 70 kg N/fed X 2500 seeds/m2 as well as the second order interaction between treatments Sakha 3 X 70 kg N/fed X 2500 seeds/m2. Data illustrated an increase in each of total cross section area, cortex area, fiber area, xylem area, fiber index per plant, cortex % and xylem % in all flax cultivars under study (Sakha 3, Giza 11 and Giza 12) as affected by fertilized flax plants with 70 kg N/fed and plant density at 1500 seeds/m2. It could be concluded that Sakha 3 cultivar and fertilizing by 70 kg N/fed with plant density of 2500 seeds/m2 to maximizing fiber yield/fed and quality.

High Molecular Weight Hyaluronan Promotes Corneal Nerve Growth in Severe Dry Eyes.

The purpose of this study was to investigate the effect of high molecular weight hyaluronan (HMWHA) eye drops on subbasal corneal nerves in patients suffering from severe dry eye disease (DED) and to evaluate the damage of subbasal corneal nerves associated with severe DED. Designed as an international, multicenter study, 16 patients with symptoms of at least an Ocular Surface Disease Index (OSDI) score of 33, and corneal fluorescein staining (CFS) of at least Oxford grade 3, were included and randomized into two study arms. The control group continued to use their individual optimum artificial tears over the study period of eight weeks; in the verum group, the artificial tears were substituted by eye drops containing 0.15% HMWHA. At the baseline visit, and after eight weeks, the subbasal nerve plexus of 16 patients were assessed by confocal laser scanning microscopy (CSLM). The images were submitted to a masked reading center for evaluation. Results showed a significant increase of total nerve fiber lengths (CNFL) in the HMWHA group (p = 0.030) when compared to the control group, where the total subbasal CNFL did not significantly change from baseline to week 8. We concluded that in severe DED patients, HMWHA from topically applied eye drops could cross the epithelial barrier and reach the subbasal nerve plexus, where it exercised a trophic effect.

Multichannel fiber sensor for time delay and optical pulse form measuring

This paper presents a description of engineering solutions and physical diagram of a device meant to measure spatially resolved time form of optical signals with detection accuracy up to 0.1 ns and a scalable number of monitoring points. It has been demonstrated that the number of simultaneously detected optical signals within the limit is up to one million. There are no moving mechanical units in the device design. A method for reducing the total length of the optical fiber based on the principle of the cascade optical delay is proposed for the multichannel sensor of diversification. The number of measured signals reaches a million. The capabilities and constraints of the described engineering solution for measuring the pulse form and monitoring the diversification of the multicomponent optical signals have been demonstrated. The principle of calculating a multichannel fiber device for recording optical pulses is presented and shown that the fiber length is up to 15 km for the detection system of 128 optical signals 100 ns long each. Generally, the number of measured signals may reach a million.

Stereological Estimation of Cholinergic Fiber Length in the Nucleus Basalis of Meynert of the Mouse Brain.

The length of cholinergic or other neuronal axons in various brain regions are often correlated with the specific function of the region. Stereology is a useful method to quantify neuronal profiles of various brain structures. Here we provide a software-based stereology protocol to estimate the total length of cholinergic fibers in the nucleus basalis of Meynert (NBM) of the basal forebrain. The method uses a space ball probe for length estimates. The cholinergic fibers are visualized by choline acetyltransferase (ChAT) immunostaining with the horseradish peroxidase-diaminobenzidine (HRP-DAB) detection system. The staining protocol is also valid for fiber and cell number estimation in various brain regions using stereology software. The stereology protocol can be used for estimation of any linear profiles such as cholinoceptive fibers, dopaminergic/catecholaminergic fibers, serotonergic fibers, astrocyte processes, or even vascular profiles.

Enhanced triple-pass hybrid erbium doped fiber amplifier using distribution pumping scheme in a dual-stage configuration

An enhanced triple-pass hybrid optical fiber amplifier in a dual-stage configuration is presented by utilizing a combination of hafnium-bismuth erbium-doped fiber (HB-EDF) and bismuth erbium-doped fiber (Bi-EDF) as gain medium. The total Erbium-doped fiber length was only 199 cm, and both HB-EDF and Bi-EDF were forward pumped by 1480 nm with an optimum pump power of 170 mW and 110 mW, respectively to provide flat gain and wideband amplification. At high input power of -10 dBm, a flat gain of about 19 dB with gain fluctuation of less than 2 dB was observed over wideband ranging from 1555–1600 nm. On the other hand, the noise figure varied from 4.8–9.3 dB within the flat gain region. The triple-pass Erbium-doped fiber amplifier has been enhanced by utilizing distribution pumping scheme in the configuration. This improvised configuration minimised the cost of the amplifier yet having the comparable performance with the dual-pump configuration. A flat gain of 17.2 dB with the corresponding noise figure below 8 dB was obtained within 1555–1600 nm.