Center Core Research Articles

A low crosstalk multi-core few-mode fiber with composite refractive index profile and air-hole embedded trench assistance

In order to reduce the fiber crosstalk for the space division multiplexing (SDM), this paper proposes a novel multi-core few-mode fiber of composite refractive index profile and dual assistance structure. On the one hand, by adopt dual assistance of air-hole embedment and trench wrapping around all the seven cores, inter-core crosstalk is greatly reduced. On the other hand, a non-circularly symmetrical refractive index (RI) profile is innovatively proposed for the six outer-ring cores, which not only weakens the inter-mode coupling but also has a suppression effect on inter-core crosstalk. The finite element method (FEM) is used to analyze the fiber structure. In the case of transmitting six spatial modes, the minimum inter-mode effective RI difference (Δneff) between the linear polarization (LP) modes of the center core and between the spatial modes of the outer-ring core are greater than 0.5 × 10−3, the inter-core crosstalk of the sixth mode LP02 at 1550 nm is less than -66dB/100km, and the relative core multiplexing factor reaches 29.24. The characteristics of this structure are significantly better than that of current commercial optical fibers, promising broad application prospects in large-capacity SDM optical communication system.

Performance Enhancement in Multicore Fiber Using Trench Assisted Technique

Analysis of crosstalk in multi-core fiber is using the trench-assisted technique. To reduce the crosstalk between the cores in the fiber, coupled-mode theory and coupled power theory are adopted for crosstalk estimation and considering different design parameters such as core pitch, bending radius, and wavelength to optimize the crosstalk performance. The homogeneous fiber, which works under single-mode operation, has been considered. The study of performance by varying the trench width is also analyzed. Crosstalk variation in outer cores and center cores of the fiber is studied. The numerical simulation results of crosstalk behavior over bending radius and wavelength are obtained.

Fiber in-line Mach-Zehnder interferometer for simultaneous measurement of transverse loading and temperature based on multi-core fiber

A fiber in-line Mach-Zehnder interferometer (MZI) is proposed and experimentally demonstrated for simultaneously measuring transverse loading and temperature. The MZI is fabricated by simply splicing a segment multicore fiber (MCF) with two short sections of multimode fibers (MMFs). The sensing principle is theoretically analyzed and the transverse loading and temperature characteristics of the sensor are investigated in experiment. The results show that the multimode interference among the center core mode (CCM), the cladding modes (CM) and outer core mode (OCM) of the MCF enables the sensor to realize the measurements of transverse loading and temperature. The transmission spectra will shift when the external transverse loading and temperature variation, and different spectral responses of the resonant dips are observed, which indicates that the sensor can implement the simultaneous transverse loading and temperature measurement by monitoring the wavelength changes of two resonant dips. The obtained sensitivities of transverse pressure and temperature can reach up to −165 pm/N and 45 pm/°C, respectively. The proposed sensor has the potential application in the fields where both temperature and transverse loading measurements are required.

A Twin-Core and Dual-Hole Fiber Design and Fabrication

We have proposed and demonstrated novel twin-hole and dual-core optical fiber. We used the normal MCVD technology to fabricate a single core fiber preform with a thin cladding. Then, two small holes were drilled in the center and on the side of the pure silica rod, the fabricated single-core fiber preform was inserted into the two holes, and then the combined preform was heated until three parts were fused. Finally, two larger holes were drilled close the center core and twin-core and dual-hole are vertically distributed. In order to retain the shape of air hole, we filled nitrogen gas in the two holes to against the ambient pressure, which made the holes collapse during the fiber drawing. The dual-hole microstructure may be used as micro-containers to inject modulation medium and aside the center core, and to induce accumulated interaction between flow material and evanescent field of the center core, therefore, it can be used as a modulation function fiber to fabricate a very compact in-fiber integrated device.

Compatibility as guiding principle for ergonomics work design and preventive occupational health and safety

Mutual adaptation and inter-changeability of system elements are very important prerequisites for machines, technical devices and products. Similar to that technical compatibility which can be achieved by standards and regulations, optimum design of human-oriented workplaces or a man-machine system cannot be attained without, e.g., a compatible arrangement of connected displays and controls. Over and above those stimulus/response relations, all technical elements and interfaces have to be designed in such a way that they do not exceed human capacity in order to optimize human well-being and overall system performance. Compatibility between the properties of the human organism on the one hand, and the adaptable technical components of a work system on the other hand, offers a great potential of preventive measures. Examples of ergonomically designed working tools show that compatibility is capable of reducing the prevalence of occupational diseases and repetitive strain injuries as well as leading to lower physiological cost in such a way that the same output results from a lower demand of human resources or even a higher performance will be attained. Compatibility also supports the quick perception and transmission of information in a man-machine system, and as a result of lower requirements for decoding during information processing, spare mental capacity may enhance occupational safety. In the field of software, compatibility also helps to avoid psychological frustration. All in all, the center core competency, which reflects the major significant function of the ergonomist in work design, consists in determining the compatibility of human capacity and planned or existing demands of work. In order to provide efficient working tools and working conditions as well as to be successful in occupational health and safety, ergonomics and industrial engineering in the future are expected to pay more attention to the rules of compatibility. Applied in an appropriate way, these rules may convince people that ergonomics can be a powerful means for reducing prevalence of occupational diseases and complaints, and has a positive effect on overall system performance. Besides presenting examples of work design according to the principle of compatibility, also methods will be shown which enable the assessment of the ergonomic quality of hand-held tools and computer input devices.

Regulating the properties of small molecular acceptors with different end groups

In this work, we designed and synthesized two small molecular acceptors, based on benzotriazole (BTA) as the center core with isopropyl alkyl chain, thienothiophene unit (TT) β-position connected n-hexane alkyl chain as wing, and using different end groups, 2-(3-oxygen generation-2, 3-2H − 1H-indane-1-alkyl)-malononitrile (IC) and 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-indane-1-alkylene) (2FIC), named BIT-IC and BIT-2FIC, respectively. The device based on PM6: BIT-IC achieved the PCE of 3.63%, which exhibited inferior performance because the device absorption is not complementary with solar spectrum, leading to the low Jsc of the device. However, the absorption band of the acceptor BIT-2FIC with 2FIC end group can reach 944 nm, and the HOMO energy level is lower than BIT-IC, therefore, the device based on PM6: BIT-2FIC can achieve more efficient exciton dissociation and charge transport, after thermal annealing treatment at 90 °C for 10 min, the device based on PM6: BIT-2FIC can achieve the PCE over 14%.

In Memory of Andy Brooks

In Memory of Andy Brooks

Paramount Importance of Core Conformational Changes for Heparin Allosteric Activation of Antithrombin.

Antithrombin is unique among serpin family protein protease inhibitors with respect to the major reactive center loop (RCL) and core conformational changes that mediate allosteric activation of its anticoagulant function by heparin. A critical role for expulsion of the RCL hinge from a native stabilizing interaction with the hydrophobic core in the activation mechanism has been proposed from reports that antithrombin variants that block this change through engineered disulfide bonds block activation. However, the sufficiency of core conformational changes for activation without expulsion of the RCL from the core is suggested by variants that are activated without the need for heparin and retain the native RCL-core interaction. To resolve these apparently conflicting findings, we engineered variants in which disulfides designed to block the RCL conformational change were combined with constitutively activating mutations. Our findings demonstrate that while a reversible constitutive activation can be engineered in variants that retain the native RCL-core interaction, engineered disulfides that lock the RCL native conformation can also block heparin allosteric activation. Such findings support a three-state allosteric activation model in which constitutive activating mutations stabilize an intermediate-activated state wherein core conformational changes and a major activation have occurred without the release of the RCL from the core but with a necessary repositioning of the RCL to allow productive engagement with an exosite. Rigid disulfide bonds that lock the RCL native conformation block heparin activation by preventing both RCL repositioning in the intermediate-activated state and the release of the RCL from the core in the fully activated state.

Time-related performance characteristics of high-sensitivity troponin I assay using manufacturer’s controls and reagents

BackgroundTroponin is a widely used cardiac protein biomarker for acute coronary syndrome. Its increasing importance drives an increasing need to assess, in real-world conditions, the performance of the tests to measure it. We evaluated the performance characteristics of high-sensitivity troponin I assay reagents and ancillary agents on the Abbott ARCHITECT ci4100, ARCHITECT i2000SR and Alinity ci using historical quality control data spanning 5 years. Design and methodRetrospective diagnostic hs-TnI quality control data were collected between 2015 and 2019 from the Abbott ARCHITECT ci4100, ARCHITECT i2000SR and Alinity ci located in the University College Dublin Clinical Research Centre Core Lab facility. Descriptive statistics for bias and variability were generated. Linear regression models were used to calculate the mean hs-TnI concentrations over Abbott quality control or reagent lot age and over time from the last calibration of the analysers. ResultsMeasurement bias on all three systems ranged between -2.49% and 3.98%. The total CV was ≤8.80%, with a within-lot variability for the reagents and controls of ≤5.45% and ≤7.13%, respectively. The between-lot CVs for reagents and controls were ≤7.16% and 6.19%, respectively. The effect of control or reagent age did not greatly affect stability over time. Results were also stable over different times from the last calibration of the analysers. ConclusionThe results of this study show that the Abbott hs-TnI assay on the ARCHITECT i2000sr and ARCHITECT ci4000 systems is quite stable in a core laboratory environment. The Alinity ci system exhibits similar performance characteristics.

A novel cooperative model in the collection of infectious waste in COVID-19 pandemic

PurposeProduction of waste has been increased exponentially due to world industrialization and urban and machine life expansion. On the other hand, the outbreak of the COVID-19 coronavirus quickly became a global crisis. This crisis has added a large amount of waste to urban waste. The purpose of this study is to create cooperation between municipal waste collector contractors.Design/methodology/approachThus, a mathematical model is proposed under uncertain conditions, which includes the volume of municipal waste and infectious waste including personal protective equipment and used equipment for patients. To reduce total costs, the results are evaluated with four cooperative game theory methods such as Shapley value, t value, core center and least core. Ultimately, the saved cost by cooperation in each coalition is allocated fairly among the contractors. Finally, a comparison was made between the solution methods based on the value of the objective function and the solution time.FindingsThe results indicate that the proposed cooperative method increases cost savings and reduces the fine of residual waste. Therefore, it can be mentioned that this kind of cooperation would finally result in more incentives for contractors to form larger coalitions. Genetic algorithms were used to solve the large-scale model.Originality/valueThe proposed model boosts the current understanding of waste management in the COVID-19 pandemic. The paper adds additional value by unveiling some key future research directions. This guidance may demonstrate possible existing and unexplored gaps so that researchers can direct future research to develop new processes.

Quasi-one-dimensional metallic conduction channels in exotic ferroelectric topological defects

Ferroelectric topological objects provide a fertile ground for exploring emerging physical properties that could potentially be utilized in future nanoelectronic devices. Here, we demonstrate quasi-one-dimensional metallic high conduction channels associated with the topological cores of quadrant vortex domain and center domain (monopole-like) states confined in high quality BiFeO3 nanoislands, abbreviated as the vortex core and the center core. We unveil via the phase-field simulation that the superfine metallic conduction channels along the center cores arise from the screening charge carriers confined at the core region, whereas the high conductance of vortex cores results from a field-induced twisted state. These conducting channels can be reversibly created and deleted by manipulating the two topological states via electric field, leading to an apparent electroresistance effect with an on/off ratio higher than 103. These results open up the possibility of utilizing these functional one-dimensional topological objects in high-density nanoelectronic devices, e.g. nonvolatile memory.

In-fiber Mach-Zehnder temperature sensor using silicone-oil-filled dual core fiber

In this paper, we proposed an in-fiber Mach-Zehnder temperature sensor based on a dual-core fiber (DCF) in which one core, working as the reference arm, is located in the center of fiber and the other core, working as the sensing arm, is suspended in an embedded fluidic channel partially filled with silicone oil. Temperature variations would mainly change the refractive index of the silicone oil and therefore the effective index of the guided modes in the suspended core, while the guided modes in the center core were barely affected. Phase difference between guided modes in the two cores would be accumulated along the DCF, thus shifting the interference spectrum of the sensor. Both experiments and numerical simulations were carried out to characterize the sensor. The spectrum shifts measured experimentally agreed well with the theoretical results. Experimental sensitivity of the DCF sensor filled with 33.5-cm-long silicone oil was found to be as high as −2.18 nm/°C, comparable to that of other interferometric sensors. The proposed sensor could be easily fabricated with good robustness and stability, which makes the sensor promising for applications such as environment and architecture monitoring.

The Lost Inner Beauty in Martial Arts: A Pencak Silat Case

The establishment of a football association in the 1930s in Indonesia marked the dominant Anglo/Euro-American control of the global diffusion of sport mingled with the imperial vision of those states to promote western colonialism’s social mores as part of a mission to ‘civilize’ people in other lands. These phenomena justify a model of spatial diffusion of sports that spread from the West as the centre (core) to colonised nations as periphery. On the other hand, the diffusion of martial arts in Indonesia passed through other routes, and established several axes driven by enculturation, so a strand of influence of elements of Chinese martial arts emerged in a certain genre of Indonesia’s martial art–pencak silat. However the intrinsic beauty of this precious cultural heritage has been lost, with the development of a focus on sport and the prowess of the ‘body as machine’, and on gaining gold medals and financial rewards.

Application of biological activity of oxazepine and 2-azetidinone compounds and study of their liquid crystalline behavior

Abstract New Schiff bases were prepared in an acidic medium by condensation p-diamino compounds with p-hydroxy benzaldehyde and the compound formed was reacted with alkyl bromide. At finally the oxazepine and 2-azetidinone compound were prepared for azo methyl group. FT-IR and 1H NMR spectrometers have confirmed the structures of such compounds. The liquid crystalline properties were studied using DSC and polarizing optical microscope. By increasing the length of the aliphatic chain, the thermal stability of the smectic liquid crystal increased with a decrease in the thermal stability of the nematic phase, Also, increasing the number of aromatic rings from three to four rings led to an increase in the thermal stability of the liquid crystalline phases due to an increase in the electronic sequence at the center core. In addition to, the oxazepine compounds did not exhibit the liquid crystalline properties, whereas the 2-azetidinone compounds showed only the nematic phase. Also, the antibacterial activities against two different types of bacteria have been studied: 1) Escherichia coli Gram (−) ve. 2) Staphylococcus Gram (+) ve. compared to the oxazepine and 2-azetidnone compounds and the Schiff bases prepared from them, it was observed that the increase in inhibition is directly proportional to the concentration. In general, the oxazepine compounds gave a high inhibition compared with the azitidine compounds, as (A14) gave the highest inhibition of (3.65 mm) against (E. Coil) and (A13) compound the highest inhibition (3.45 mm) against (Staphylococcus), Also, the compounds inhibition of (E. coil) bacteria were higher than that of (staphylococcus).

Interference-Suppressed and Cluster-Optimized Hyperspectral Target Extraction Based on Density Peak Clustering

Target extraction can provide a prior knowledge for spectral unmixing, unsupervised hyperspectral image classification, and unsupervised target detection tasks, which is of great practice. Considering that the traditional endmember extraction algorithms such as automatic target generation process (ATGP) and simplex growing algorithm (SGA) are sensitive to the burst noise caused by hyperspectral sensor imaging and cannot extract the appropriate target set to simultaneously guide the various tasks, a weighted target extraction algorithm based on the density peak clustering (DPC) is proposed in this article. First, DPC is extended to hyperspectral images, and the decision graph is generated according to the density and distance of each pixel to effectively classify the regions with different attributes such as burst noise, cluster center, cluster boundary, and cluster core. On the basis, three DPC-based weighted vectors are designed, and the weighted target extraction algorithms W-ATGP and W-SGA are put forward which allocates a lower weight than the core pixel to the interference so as to reduce its impact on ATGP and SGA while obtaining the high-quality targets for various tasks. The experimental results on three datasets show that the accuracies of the target sets extracted by W-ATGP and W-SGA are higher than that of ATGP and SGA, no matter as the prior knowledge of spectral unmixing, unsupervised hyperspectral image classification, or unsupervised target detection, which verifies the effectiveness of the proposed methods.

Sharing Data from an Academic Cancer Center Biospecimen and Proteomic Core Facilities through the Proteomics Data Commons

Data sharing is critical for open science and often required by funding organizations and journals. NCI has developed the Proteomics Data Commons (PDC) as part of the Cancer Research Data Commons, an infrastructure that allows users to share, analyze, and store results, utilizing the storage and compute resources of the cloud. To date most of the data available in the various Data Commons are submitted from large multi-institution research programs funded by NCI with teams of specialists from multiple scientific disciplines. Here we describe our experiences and summarize the recommended best practices for sharing a set of proteomics and related biospecimen data and analyses results from smaller scale proteomics studies conducted in an academic medical center core facility using patient samples of lung adenocarcinoma. Mapping and depositing data in the manner described here harmonizes user’s data to a common data model and community standards, making it possible to view the data alongside other high value cancer studies available in the PDC. Availability: Data, metadata, protocols with peptide and protein identifications are available at the PDC. (https:// pdc.cancer.gov/pdc/study/PDC000231).

A Phase IV Trial of Proton Therapy in Children: The First Report from SJPROTON1

Background: Early reports suggest adverse events following proton therapy (PT) for childhood cancer are more prevalent. We evaluated treatment-failure and toxicity following Pencil Beam Scanning (PBS)-PT in children. Methods: The single-institution Phase IV trial screened 856 children, of which 528 were eligible for PBS-PT, and 500 enrolled in SJPROTON1 from 2017–2020. The median follow-up was 2.1 years (range 1.1-4.4). The primary objective was the cumulative incidence (CI) of ≥grade 3 non-hematologic, PBS-PT attributable toxicity by CTCAE v4.0. Additional outcomes included PBS-PT toxicity attributable hospitalization, procedures, and treatment-related mortality. Toxicities including necrosis, vasculopathy, neurologic deficits, and fracture/osteoradionecrosis were further characterized (any grade). Competing risk regression was used to evaluate predictors of ≥grade 3 PBS-PT attributable toxicity. Findings: At two years, the event-free survival was 73.2% (95% CI, 68.9%-77.8%). Distant and local failure predominated with a 2-year CI of 16.5% (95% CI 13.1-20.4) and 6.8% (95% CI 4.6-9.5) respectively. The 4 year CI of ≥grade 3 toxicity was 24.5%; including necrosis (3.7%), neurologic deficit (2.9%), and fracture/osteoradionecrosis (0.79%). The rates of PBS-PT-toxicity attributable hospitalization and procedures were 3.9% and 7.6%. Predictors of any ≥grade 3 toxicity included baseline total toxicity burden (TTB) (HR 1.043, 95% CI 1.012-1.07, p=0.007), and mixed photon/PBS-PT (HR 2.62, 95% CI 1.51-4.54, p=0.006) in CNS patients, and pelvic radiotherapy (HR 4.25, 95% CI 1.08-16.72, p=0.038), and TTB (HR 1.1, 95% CI 1.04-1.16, p=0.002) in non-CNS patients. Interpretation: PBS-PT yields a low incidence of toxicity, but subsets are at increased risk, and may require additional procedures or hospitalization. Funding: This work was supported by ALSAC and Cancer Center Core Grant CA21765. Declaration of Interest: None to declare. Ethical Approval: The SJPROTON1 trial was reviewed and approved by the Institutional Review Board at St. Jude. Informed consent was obtained from the parent, caregiver, or patient, with assent from the patient, as appropriate.

Experimental characterization and damage reliability analysis of central core strand extracted from steel wire rope

Wire ropes are the main element of lifting and handling equipments, they are constituted of several elements, the most important one is the central core (strand). The main objective of this work is the study of the problems occurring due to the risks of premature rupture of this element, that’s why we performed statics tensile tests on virgin central core and pre-damaged ones with 1, 2, …,6 artificially cut wires. Subsequently, we calculated and connected the reliability and the damage through the material’s life fraction, these two parameters allowed us to asses the degradation of the center core strand of the wire rope.

Assessing the conservation and enhancement value of revegetated strips on arthropod assemblages in a pasture landscape

Examining population dynamics of arthropod communities in habitats neighboring arable lands is essential to understanding how agroecosystems can be engineered to enhance ecosystem services and contribute to sustainable intensification. Arthropods comprise the bulk of faunal biomass on farms, are taxonomically diverse, and are the main drivers of many ecosystem functions. This study aimed to compare arthropod assemblages in revegetated strips of native plants and exotic pastures, and examine taxa of beneficial arthropods in revegetated strips and adjacent pasture in early spring (September 2009) and mid-summer (December 2009–January 2010) on two farms in southeastern Gippsland, Victoria, Australia. Arthropod community assemblages were distinctly different between revegetated strips and adjacent pasture with the exception of functional groups in early spring. Several taxa of beneficial arthropods including Carabidae (ground beetles) and Syrphidae (hoverflies) were of similar abundance in the two habitats. Only Formicidae (ants) were of higher abundances in revegetated strips compared to adjacent pasture in both seasons. Five of the 10 ant genera present, seven spider families and Dolichopodidae flies (long-legged flies) were found exclusively in revegetated strips. Apidae (bees) and Tachinidae (tachinid flies) had higher abundances in revegetated strips compared to 80 m into the adjacent pasture in mid-summer. Lycosidae (wolf spiders) were more abundant along the edge of revegetated strips and 20 m into adjacent pasture compared to the center (core) of revegetated strips and 80 m into pasture. These results illustrate that beneficial arthropods use revegetated strips as refugia and that revegetated strips clearly enhanced biological conservation of arthropods in pasturelands. Relevance of findings to enhanced biological control is also discussed.

Membrane properties of ether-type phosphatidylcholine bearing partially fluorinated C18-monoacetylenic chains and their applicability to membrane protein reconstitution matrices

To examine the applicability of fluorinated membrane-forming phospholipids to reconstitution matrices for functional membrane proteins, the membrane properties of a synthetic ether-type phosphatidylcholine (PC) bearing partially fluorinated C18-monoacetylenic (9-octadecynyl) chains, DF8CCH8PC, were compared with those of its non-fluorinated counterpart, DH8CCH8PC. Light-harvesting complex 2 (LH2) and the light-harvesting 1‒reaction center core complex (LH1-RC) isolated from purple photosynthetic bacteria were employed as probe membrane proteins to evaluate the extent to which their reconstitution into DF8CCH8PC membranes could proceed. DF8CCH8PC formed more expanded and more stable fluid monolayers than DH8CCH8PC at the air-water interface at 25 °C; the former PC molecule occupied an area of ca. 0.70 nm2 at a collapse pressure, πc, of 52 mN/m, while the latter occupied an area of ca. 0.55 nm2 at a πc of 45 mN/m. In contrast, the molecular motion detected using fluorescent probes was much more restricted in DF8CCH8PC bilayers than in DH8CCH8PC ones. Although the reconstitution efficiencies of both LH2 and LH1-RC into DF8CCH8PC bilayers were lower than those into DH8CCH8PC bilayers, the membrane proteins incorporated into DF8CCH8PC bilayers showed increased thermostability. The increased thermostability of these proteins in fluorinated PC membranes might be due to the restricted molecular motion in the hydrophobic chains. The results of this study suggest that partially fluorinated PCs can be useful materials for the construction of lipid‒functional membrane protein assemblies including large membrane protein complexes, such as LH1-RC, for biotechnological applications.