Line Rate Research Articles

Estimating the shielding failure flashover rate of single-circuit overhead lines with horizontal phase configuration via stochastic lightning attachment simulations

A methodology is proposed for estimating the shielding failure flashover rate (SFFOR) of single-circuit overhead lines with horizontal phase configuration. An application to a 66 kV overhead line is presented. A stochastic lightning attachment model is employed, based on the concept of fractal structures, to compute the probability of shielding failure to the line. Results of stochastic modeling are combined with those of an ATP-EMTP model for estimating the critical lightning currents causing flashover of the line insulation. Shielding failure results of the proposed methodology are compared and discussed with results obtained employing the methodology of the IEEE Std 1243. Innovation of this work lies in estimating the SFFOR of overhead lines by considering the stochastic nature of lightning attachment, physical criteria associated with leader discharges’ inception and propagation, as well as electromagnetic transient simulations to predict lightning-related flashover to overhead lines accurately.

RAVEN: Stateless Rapid IP Address Variation for Enterprise Networks

Enterprise networks face increasing threats against the privacy of their clients. Existing enterprise services like Network Address Translation (NAT) offer limited privacy protection, at the cost of requiring per-flow state. In this paper, we introduce RAVEN (Rapid Address Variation for Enterprise Networks), a network-based privacy solution that is complementary to application-layer defenses. RAVEN protects privacy by frequently changing the client's public IP address. With RAVEN, a client is not limited to using a single IP address at a given time, or even for a given connection. RAVEN goes further, breaking the association between packets that belong to the same connection by frequently changing the client's IP address within a single connection. RAVEN achieves this through a novel division of labor: the client uses a transport protocol, like QUIC, that supports seamless connection migration, and decides when to switch its IP address, while the enterprise network actually changes the client's IP address in a stateless manner at line rate and ensures end-to-end packet delivery. We implement RAVEN using QUIC and off-the-shelf programmable switches. We deploy RAVEN in a test IPv6 network and evaluate its defense against webpage fingerprinting attacks. Even with a strong adversary, the average precision of the best adaptive attacks drops from 0.96 to 0.84, with a 0.5% degradation in client throughput. When RAVEN changes IP addresses at unpredictable frequency, the precision of the best attacks falls to 0.78---the same effectiveness as WTF-PAD.

Fronthaul latency and capacity constrained cost-effective and energy-efficient 5G C-RAN deployment

The third-generation partnership project (3GPP) has identified different new functional split points, defined as options 1–7, between the baseband unit (BBU) and the remote unit (RU) for the 5G centralized radio access networks (C-RANs). The functional splits facilitate lower fronthaul line rate and latency requirements while imposing technical complexity and cost-efficiency trade-offs. Among all the functional split options, the standardization groups such as 3GPP, Open RAN (O-RAN), and small cell forum have selected option-7 as the most suitable choice for the 5G C-RAN deployment that can meet the operator’s requirements. One of the biggest challenges for designing option-7 functional split-based C-RAN is the capacity and latency requirement fulfillment as specified by 3GPP, while minimizing the deployment cost. In this regard, we propose an optimization model for cost-effective and energy-efficient option-7 functional split-based C-RAN architecture using wavelength division multiplexed passive optical network (WDM-PON) in the fronthaul. For the given locations of the next-generation core (NGC) and the set of RUs, the proposed optimization model explores the most suitable locations for the placement of BBU pools and arrayed waveguide gratings (AWGs). It provides complete interconnection details among NGC, BBU pools, AWGs, and RUs. It also provides the optimal number of digital units in each selected BBU pool, the splitting ratio of each AWG, and maximum fronthaul reach, satisfying the fronthaul latency, capacity, and power budget constraints. To the best of our knowledge, for the first time, we estimate the worst-case queuing delay for the upstream traffic flow using the G/G/1 queuing model and investigate its impact on fronthaul latency and deployment cost for different RU configurations. We compare the performance of the proposed option-7 functional split-based C-RAN with the traditionally used option-8 functional split-based C-RAN in terms of the deployment cost and fronthaul latency improvement.

Experimental study on the wear mechanism of the contact line in rigid pantograph-catenary systems

An experimental study was conducted to assess the wear mechanism of the commonly used contact lines in rail services. A high-speed sliding electrical contact wear test machine was applied to pantograph-catenary systems (PCS). The friction coefficient, arc discharge energy, current-passing efficiency, contact resistance, and contact loss rate were recorded or calculated. The impact of the test parameters on the wear of the contact line was analyzed. Our results showed that the wear rate of the contact line was inversely proportional to the normal force and directly proportional to the sliding speed. The wear of the contact line at constant current mainly included mechanical and electrical wear. With declining system stability, electrical wear gradually became the key to determining total contact line wear. When the normal force and sliding speed were maintained constant, the wear rate of the contact line fluctuated with changes in the current. Under non-current conditions, mostly mechanical wear occurred in the contact line, and the total wear was the highest. When the current (I) was maintained at 250 A, the electrical wear of the contact line was the highest, and the total wear was the highest under current-carrying conditions. However, at I = 350 A, the electrical and mechanical wear of the contact line were both at a low level, and the total wear of the contact line was the lowest. When I was increased to 450 A, the total wear of the contact line contributed to material transfer wear based on electrical and mechanical wear. In all tests, the maximum wear rate of the contact line (6.9712 × 10−3 g/km) was 3.138 times the minimum wear rate of the contact line (2.2215 × 10−3 g/km).

Single-wavelength polarization- and mode-division multiplexing free-space optical communication at 689 Gbit/s in strong turbulent channels.

We experimentally demonstrated, for, it is believed, the first time, high-capacity polarization- and mode-division multiplexing free-space optical transmission with adequate strong turbulence resiliency. A compact spatial light modulator-based polarization multiplexing multi-plane light conversion module was employed to emulate strong turbulent links. By employing advanced successive interference cancellation multiple-input multiple-output decoder and redundant receive channels, the strong turbulence resiliency was significantly improved in a mode-division multiplexing system. As a result, we achieved a record-high line rate of 689.2 Gbit/s, channel number of 10, and net spectral efficiency of 13.9 bit/(s Hz) in a single-wavelength mode-division multiplexing system with strong turbulence.

Nitric Oxide and Globin Glb1 Regulate Fusarium oxysporum Infection of Arabidopsis thaliana.

Plants continuously interact with fungi, some of which, such as Fusarium oxysporum, are lethal, leading to reduced crop yields. Recently, nitric oxide (NO) has been found to play a regulatory role in plant responses to F. oxysporum, although the underlying mechanisms involved are poorly understood. In this study, we show that Arabidopsis mutants with altered levels of phytoglobin 1 (Glb1) have a higher survival rate than wild type (WT) after infection with F. oxysporum, although all the genotypes analyzed exhibited a similar fungal burden. None of the defense responses that were analyzed in Glb1 lines, such as phenols, iron metabolism, peroxidase activity, or reactive oxygen species (ROS) production, appear to explain their higher survival rates. However, the early induction of the PR genes may be one of the reasons for the observed survival rate of Glb1 lines infected with F. oxysporum. Furthermore, while PR1 expression was induced in Glb1 lines very early on the response to F. oxysporum, this induction was not observed in WT plants.

Research on Real-time Simulation of Automobile Production Line based on Discrete Event and Multiagent

To improve the production efficiency and quality of the automobile production line, optimize the balance rate of the production line, and realize the digital mapping of the new energy automobile production line. The critical production lines of new energy vehicles are accurately modeled and visualized in the Anylogic environment using multi-agent and discrete event modeling methods. Through the establishment of data connection with actual equipment and the simulation of the operation of the production line, a visual simulation and analysis interface of the production line is built to detect the impact of process time on the balance rate, whether the inventory strategy is reasonable and whether it meets the actual production requirements, reduce the optimization cost, and provide a new idea for the digital twin system of the automobile production line.

Video-rate mid-infrared photothermal imaging by single-pulse photothermal detection per pixel.

By optically sensing absorption-induced photothermal effect, mid-infrared (IR) photothermal (MIP) microscope enables super-resolution IR imaging of biological systems in water. However, the speed of current sample-scanning MIP system is limited to milliseconds per pixel, which is insufficient for capturing living dynamics. By detecting the transient photothermal signal induced by a single IR pulse through fast digitization, we report a laser-scanning MIP microscope that increases the imaging speed by three orders of magnitude. To realize single-pulse photothermal detection, we use synchronized galvo scanning of both mid-IR and probe beams to achieve an imaging line rate of more than 2 kilohertz. With video-rate speed, we observed the dynamics of various biomolecules in living organisms at multiple scales. Furthermore, by using hyperspectral imaging, we chemically dissected the layered ultrastructure of fungal cell wall. Last, with a uniform field of view more than 200 by 200 square micrometer, we mapped fat storage in free-moving Caenorhabditis elegans and live embryos.

Field Trial of SDN-Controlled Probabilistic Constellation Shaping Supporting Multiple Rates Over a Coupled-Core Multi-Core Fiber

Space division multiplexing (SDM) is being investigated in support of traffic growth. SDM networks offer multiplexing over space and spectrum dimensions. Probabilistic constellation shaping (PCS) is a solution to optimize spectral efficiency by adapting the constellation of a M-ary quadrature amplitude modulated (QAM) signal to physical layer impairments. At the control plane, in the recent years NETCONF and YANG have been identified as the protocol and the data modeling language, respectively, for the configuration and management of network devices. Significant effort has also been directed to network disaggregation and vendor neutrality: an example is the work done within the OpenConfig consortium. <p xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">In this paper, we present a SDM field trial based on a deployed coupled-core four-core fiber, where a software-defined network (SDN) controller configures probabilistic constellation shaping through NETCONF, by optimizing spectral efficiency either with respect to the path length, or in response to degradations due to soft failures. The NETCONF protocol relies on the OpenConfig YANG data model to configure and manage transceivers. In the field trial the integrated data and control planes are demonstrated with multiple rates (800-850-900-950-1000 Gb/s) for optical reach values ranging from 910 km to 2730 km. Soft failures are also introduced and a characterization of their impact on transmission performance is provided in order to design the recovery strategy deployed by SDN controller. Indeed, depending on the changes in the electrical signal-to-noise ratio, the SDN controller reconfigures the constellation shaping to restore the optical connection affected by the failure with a reduced line rate.

Flexible transceiver for an access network: a multicarrier entropy loading approach

To cope with the extraordinary bandwidth demand, an optical access network based on point-to-multipoint (P2MP) topology has been widely applied. Recently, flexible transceivers have been investigated to maximize the optical power budget of optical network units for increasing the capacity of passive optical networks. In this work, we experimentally demonstrate a low-cost, high-bandwidth P2MP solution based on multicarrier modulations and probabilistic constellation shaping technology by reusing a 10G class directly modulated laser and avalanche photodetector for the first time to our knowledge. The proposed P2MP solution is capable of achieving fine granularity data rate adjustment from 12.5 Gb/s up to 63 Gb/s. We discuss the hardware implementation aspect of the proposed multicarrier entropy loading flexible transceiver. By means of a real-time transmission experiment, we show that the proposed P2MP solution can achieve a 29 dB power budget at a symmetric 53 Gb/s line rate, which makes it well positioned to support non-residential P2MP applications such as passive optical local area networks and fiber-to-the-office.

Multi-neuronal recording in unrestrained animals with all acousto-optic random-access line-scanning two-photon microscopy.

To understand how neural activity encodes and coordinates behavior, it is desirable to record multi-neuronal activity in freely behaving animals. Imaging in unrestrained animals is challenging, especially for those, like larval Drosophila melanogaster, whose brains are deformed by body motion. A previously demonstrated two-photon tracking microscope recorded from individual neurons in freely crawling Drosophila larvae but faced limits in multi-neuronal recording. Here we demonstrate a new tracking microscope using acousto-optic deflectors (AODs) and an acoustic GRIN lens (TAG lens) to achieve axially resonant 2D random access scanning, sampling along arbitrarily located axial lines at a line rate of 70 kHz. With a tracking latency of 0.1 ms, this microscope recorded activities of various neurons in moving larval Drosophila CNS and VNC including premotor neurons, bilateral visual interneurons, and descending command neurons. This technique can be applied to the existing two-photon microscope to allow for fast 3D tracking and scanning.

Increased demand for FAD synthesis in differentiated and stem pancreatic cancer cells is accomplished by modulating FLAD1 gene expression: the inhibitory effect of Chicago Sky Blue.

FLAD1, along with its FAD synthase (FADS, EC 2.7.7.2) product, is crucial for flavin homeostasis and, due to its role in the mitochondrial respiratory chain and nuclear epigenetics, is closely related to cellular metabolism. Therefore, it is not surprising that it could be correlated with cancer. To our knowledge, no previous study has investigated FLAD1 prognostic significance in pancreatic ductal adenocarcinoma (PDAC). Thus, in the present work, the FAD synthesis process was evaluated in two PDAC cell lines: (a) PANC-1- and PANC-1-derived cancer stem cells (CSCs), presenting the R273H mutation in the oncosuppressor p53, and (b) MiaPaca2 and MiaPaca2-derived CSCs, presenting the R248W mutation in p53. As a control, HPDE cells expressing wt-p53 were used. FADS expression/activity increase was found with malignancy and even more with stemness. An increased FAD synthesis rate in cancer cell lines is presumably demanded by the increase in the FAD-dependent lysine demethylase 1 protein amount as well as by the increased expression levels of the flavoprotein subunit of complex II of the mitochondrial respiratory chain, namely succinate dehydrogenase. With the aim of proposing FADS as a novel target for cancer therapy, the inhibitory effect of Chicago Sky Blue on FADS enzymatic activity was tested on the recombinant 6His-hFADS2 (IC50 = 1.2 μm) and PANC-1-derived CSCs' lysate (IC50 = 2-10 μm). This molecule was found effective in inhibiting the growth of PANC-1 and even more of its derived CSC line, thus assessing its role as a potential chemotherapeutic drug.

Peripherally inserted central venous catheter in Autologous Hematopoietic Stem Cell Transplantation: Feasibility and Outcome

Objectives: This study describes our experience using PICC in patients submitted to autologous stem cell transplant (ASCT) regarding the time of use, withdrawal reasons, and complications.&#x0D; Methods: A retrospective cohort of 143 patients from 2017 and 2019, with a PICC inserted before the ASCT. &#x0D; Results: Regarding baseline disease, 104 (73%) of patients had multiple myeloma. The median days of use was 15 (1 – 37) per catheter. More than 80% of PICC remained in place after D+15, and 112 (78%) patients had the PICC removed at discharge. Only 13 (9%) patients had replacement of the PICC. The rates of central line associate bloodstream infection and thrombosis were 1.36 and 1.36 events per 1,000 PICC days, respectively.&#x0D; Conclusions: PICCs were successfully remained until discharge, with manageable rates of complications. All procedures were executed by nurses at the bedside. We concluded that PICC is a safe and feasible alternative to CVC for ASCT.

P4Tune: Enabling Programmability in Non-Programmable Networks

Data plane programmability has attracted significant attention, permitting network operators to run customized packet processing functions. Unfortunately, networks today are still largely dominated by proprietary fixed-function devices. It is challenging for operators to completely migrate to programmable data planes (PDPs) due to the economical costs of replacing equipment and limited expertise in maintaining and operating programmable networks. This article introduces P4Tune, a cost-efficient architecture that uses passive PDPs coupled with optical taps. P4Tune runs customized packet processing functions operating at line rate and collects network information with nanosecond resolution. This visibility enables intelligent algorithms residing in the control plane to construct configuration rules and apply them on the legacy devices, thus creating a closed control loop. P4Tune brings the benefits of processing traffic at line rate to legacy networks. Additionally, by using PDPs passively, the architecture can be safely deployed without disrupting current network operations, fostering incremental use of PDPs (i.e., no need to deploy complex code at once). The article demonstrates three applications of the proposed architecture related to Quality of Service (QoS) and cybersecurity.

Self-Adaptive Sampling Based Per-Flow Traffic Measurement

Per-flow traffic measurement in the high-speed network plays an important role in many practical applications. Due to the limited on-chip memory and the mismatch between off-chip memory speed and line rate, sampling-based methods select and forward a part of flow traffic to off-chip memory, which complements sketch-based solutions in estimation accuracy and online query support. However, most current work uses the same sampling probability for all flows, leading to the waste in storage and communication resources. In practice, different flows often require different sampling rates to meet the same accuracy constraint. This paper presents self-adaptive sampling, a framework to sample each flow with a probability adapted to flow size/spread. Then we propose three algorithms, SAS-LC, SAS-LOG, and SAS-HYB. SAS-LC and SAS-LOG are geared towards per-flow spread estimation and per-flow size estimation by using different compression functions. SAS-HYB combines the advantages of SAS-LC and SAS-LOG, showing higher efficiency when both small flows and large flows are interested. We implement our estimators in hardware using NetFPGA. Experimental results based on real Internet traces show that, compared to the state-of-the-art in per-flow spread estimation, SAS-LC can save around 10% on-chip space and reduce up to 40% communication cost for large flows. In per-flow size estimation, SAS-LOG can save 40% on-chip space and reduce up to 96% communication costs for large flows. Moreover, SAS-HYB’s on-chip memory usage will not be larger than SAS-LC or SAS-LOG and can save up to 19% on-chip space than SAS-LOG when both small flows and large flows are interested.

High rate of radiolucent lines following the cemented original design of the ATTUNE total knee arthroplasty.

Loosening of components after total knee arthroplasty (TKA) can be associated with the development of radiolucent lines (RLLs). The aim of this study was to assess the rate of formation of RLLs in the cemented original design of the ATTUNE TKA and their relationship to loosening. A systematic search was undertaken using the Cochrane methodology in three online databases: MEDLINE, Embase, and CINAHL. Studies were screened against predetermined criteria, and data were extracted. Available National Joint Registries in the Network of Orthopaedic Registries of Europe were also screened. A random effects model meta-analysis was undertaken. Of 263 studies, 12 were included with a total of 3,861 TKAs. Meta-analysis of ten studies showed high rates of overall tibial or femoral RLLs for the cemented original design of the ATTUNE TKA. The overall rate was 21.4% (95% confidence interval (CI) 12.7% to 33.7%) for all types of design but was higher for certain subgroups: 27.4% (95% CI 13.4% to 47.9%) for the cruciate-retaining type, and 29.9% (95% CI 15.6% to 49.6%) for the fixed-bearing type. Meta-analysis of five studies comparing the ATTUNE TKA with other implants showed a significantly higher risk of overall tibial or femoral RLLs (odds ratio (OR) 2.841 (95% CI 1.219 to 6.623); p = 0.016) for the ATTUNE. The rates of loosening or revision for loosening were lower, at 1.2% and 0.9% respectively, but the rates varied from 0% to 16.3%. The registry data did not report specifically on the original ATTUNE TKA or on revision due to loosening, but 'all-cause' five-year revision rates for the cemented ATTUNE varied from 2.6% to 5.9%. The original cemented ATTUNE TKA has high rates of RLLs, but their clinical significance is uncertain given the overall low associated rates of loosening and revision. However, in view of the high rates of RLLs and the variation in the rates of loosening and revision between studies and registries, close surveillance of patients who have undergone TKA with the original ATTUNE system is recommended.

The evolution of treatment patterns in patients (pts) with locally advanced or metastatic urothelial cancer (la/mUC) and clinical outcomes: Results of a longitudinal observational cohort study in England.

e16559 Background: Treatment (tx) guidelines for pts with la/mUC in England have evolved over the last decade following the approval of successive immune checkpoint inhibitors (ICIs). However, the impact of this evolution on routine clinical practice (RCP) remains unclear. We aimed to describe shifts in tx patterns and associated clinical outcomes in RCP in England. Methods: This retrospective cohort study included pts aged ≥18 years, with primary stage III/IV UC diagnosis (dx) between Jan 1, 2013 and Dec 31, 2020, in the National Cancer Registration Dataset with follow-up to May 31, 2022. Pts’ dx were stratified at Dec 31, 2017, to split the cohort into pre- and post-ICI eras. Lines of systemic therapy were derived via an algorithm using data from the Systemic Anti-Cancer Therapy dataset. Summary statistics and overall survival (OS) were calculated and compared using χ2 and log-rank tests, respectively. The Kaplan-Meier method was used to estimate median OS from dx and from systemic tx initiation. Results: In the pre- and post-ICI groups, the majority of pts were male (65.7% and 65.5%) and mean modified Charlson-Deyo Comorbidity Index was 3.4 and 3.5, respectively. Mean age was 73.2 years in both groups, while a higher percentage of pts in pre-ICI era had stage IV disease at dx (68.3% and 50.0%; p&lt;0.001). The rate of first line (1L) tx increased from 30.4% to 35.3% (p&lt;0.001) and second line (2L) from 31.2% to 37.3% (p&lt;0.001). The proportion of pts who received ICI in any line increased from 13.7% to 31.6% (p&lt;0.001). Median OS from 1L tx improved from 13.8 to 15.5 mo. Conclusions: While pt demographics did not change considerably between the two groups, 1L and 2L tx rates moderately increased over time, although remained below 40%. In both groups, &gt;85% of treated pts received 1L platinum chemotherapy, consistent with guidelines. In the post-ICI era, approximately one-third of treated pts received ICI therapy in any line. Improved OS from 1L tx could be partially attributable to the increased availability and uptake of ICIs. [Table: see text]

Accounting for differential rotation in calculations of the Sun’s angular momentum-loss rate

Context. Sun-like stars shed angular momentum due to the presence of magnetised stellar winds. Magnetohydrodynamic models have been successful in exploring the dependence of this ‘wind-braking torque’ on various stellar properties; however the influence of surface differential rotation is largely unexplored. As the wind-braking torque depends on the rotation rate of the escaping wind, the inclusion of differential rotation should effectively modulate the angular momentum-loss rate based on the latitudinal variation of wind source regions. Aims. Here we aim to quantify the influence of surface differential rotation on the angular momentum-loss rate of the Sun, in comparison to the typical assumption of solid-body rotation. Methods. To do this, we exploited the dependence of the wind-braking torque on the effective rotation rate of the coronal magnetic field, which is known to be vitally important in magnetohydrodynamic models. This quantity has been evaluated by tracing field lines through a potential field source surface (PFSS) model, driven by ADAPT-GONG magnetograms. The surface rotation rates of the open magnetic field lines were then used to construct an open-flux weighted rotation rate, from which the influence on the wind-braking torque could be estimated. Results. During solar minima, the rotation rate of the corona decreases with respect to the typical solid-body rate (the Carrington rotation period is 25.4 days), as the sources of the solar wind are confined towards the slowly rotating poles. With increasing activity, more solar wind emerges from the Sun’s active latitudes which enforces a Carrington-like rotation. Coronal rotation often displays a north-south asymmetry driven by differences in active region emergence rates (and consequently latitudinal connectivity) in each hemisphere. Conclusions. The effect of differential rotation on the Sun’s current wind-braking torque is limited. The solar wind-braking torque is ∼10 − 15% lower during solar minimum, (compared with the typical solid body rate), and a few percent larger during solar maximum (as some field lines connect to more rapidly rotating equatorial latitudes). For more rapidly rotating Sun-like stars, differential rotation may play a more significant role, depending on the configuration of the large-scale magnetic field.

Quercetin can be a more reliable treatment for metastatic prostate cancer than the localized disease: An in vitro study.

Quercetin is a plant flavonoid that has been recognized to have anti-inflammatory, antioxidant and anti-proliferative activities. This study aims to evaluate the inhibitory effects of quercetin against prostate malignancy in vitro and the underlying resistance mechanism. IC50 values of quercetin were determined by MTT assay. Annexin-V/PI staining was used to measure the rate of apoptosis. DNA cell cycle was analysed by PI staining method. Real-time PCR was performed to assess mRNA levels of OPN isoforms, VEGF isoforms, P53 and KLK2. Migration potential, proliferative capability and nucleus morphology of cells were evaluated by the scratch-wound assay, colony-forming assay and Hoechst staining, respectively. Quercetin significantly increased the apoptosis rate of PC-3 and LNCaP cell lines, arrested the cell cycle at the sub-G1/G1 phase, and reduced the migration potential and colony-forming capability. Moreover, upregulation of apoptosis-related genes and downregulation of genes involved in proliferation and angiogenesis was also observed. Although our results elucidated that quercetin has antitumor effects on PC-3 and LNCaP, for the first time, we showed that quercetin treatment causes alterations in the expression of OPN and VEGF isoforms, which are cancer-promoting modulators through various processes such as angiogenesis and drug-resistance. Prostate malignant cells can dodge the anti-carcinogenic properties of quercetin via modulation of OPN and VEGF isoforms in vitro. Therefore, quercetin acts as a double-edged sword in prostate cancer treatment.

Synthesis, and Anticancer Evaluation of 4-[(Indol-3-yl)-arylmethyl]-1-phenyl-3-methyl-5-pyrazolone Derivatives via a Magnetic Aminated Starch Biocatalyst

An eco-friendly biocatalyst was constructed in three steps. In the first step, the tosylated starch (TsST) was synthesized by using a 4-toluenesulfonyl chloride. In the second step, the aminated starch was synthesized via the reaction of TsST with para-phenylenediamine. In the third step, the magnetic biocatalyst was fabricated by an in situ coprecipitation process from ferric and ferrous salts in the existence of aminated starch (AST). The biocatalyst was characterized by 1H NMR, EDX, FESEM, FTIR, VSM, and TGA analyses. The magnetic aminated starch (MAST) was used as a biocatalyst for the synthesis of 4-[(indol-3-yl)-arylmethyl]-1-phenyl-3-methyl-5-pyrazolone derivatives. The various products were prepared in noteworthy yields (85–93%) in fast reaction times (35–80 min) without laborious work-up procedures. The anticancer evaluation of some 4-[(indol-3-yl)-arylmethyl]-1-phenyl-3-methyl-5-pyrazolones derivatives was studied on the survival rate of breast cancer cell lines (MCF-7) and human fibroblast cells by using an MTT assay. Additionally, recovery of the biocatalyst was studied, and results showed that the MAST was easily isolated from the reaction flask and could be recycled for up to six consecutive cycles without meaningfully falling in its efficiency.