Circular Spot Research Articles

Evaluation of fungicides and herbicides against groundnut collar rot pathogen Aspergillus niger under in vitro conditions

Collar rot of groundnut is caused by Aspergillus niger Van Tieghem. It is a soilborne pathogen, usually the occurrence of collar rot disease during the early stages of crop growth and results in high seedling mortality. The collar rot pathogen produces both seed rot (pre-emergence) and seedling blight symptoms (post-emergence). In case of seed rot, black masses of mycelium were seen on the surface of seed. Later, the pathogen causes rotting of seed. Rotten seed do not emerge from the soil. Collar rot affected seedlings show a circular brownish spot on cotyledon region. Later, the discoloured area rapidly disintegrates spreading to the stem and hypocotyl. The affected plants show general wilting, rotting just below the ground level. An experiment was conducted under in vitro conditions to evaluate the fungicides against the collar rot pathogen apart from these fungicides, some herbicides also evaluated to test their non-target effect against collar rot pathogen. A total of six fungicides and eight herbicides were evaluated by using poisoned food technique. Maximum inhibition (100%) of radial growth of A. niger was obtained with tebuconazole at recommended and half recommended dosage and least inhibition was obtained with mancozeb and azoxystrobin. Among herbicides pendimethalin was shown maximum inhibition (100%) against A. niger and least inhibition was observed with herbicide imazythapyr and imazythapyr + imazamox.

Emittance matching of a slow extracted beam for a rotating gantry

The introduction of a heavy-ion rotating gantry is in progress at the Heavy Ion Medical Accelerator in Chiba (HIMAC) for realizing high-precision cancer therapy using heavy ions. A scanning irradiation method will be applied to this gantry course with 48–430MeV/u beam energy. In the rotating gantry, the horizontal and vertical beam parameters are coupled by its rotation. To maintain a circular spot shape at the isocenter irrespective of the gantry angle, achieving symmetric phase space distribution of the horizontal and vertical beam at the entrance of the rotating gantry is necessary. Therefore, compensating the horizontal and vertical emittance is necessary. We consider using a thin scatterer method to compensate the emittance. After considering the optical design for emittance matching, the scatterer device is located in the high-energy beam transport line. In the beam commissioning, we confirm that the symmetrical spot shape is obtained at the isocenter without depending on the gantry angle.

FIRST REPORT OF POWDERY MILDEW ON LAGENARIA SICERARIA CAUSED BY PODOSPHAERA XANTHII IN INDIA

The bottle gourd (Lagenaria siceraria, family Cucurbitaceae) is a medicinal plant (Sirohi and Sivakami, 1991) widely cultivated throughout India. In December 2014, powdery mildew symptoms were observed on L. siceraria in different fields of the Odisha state (India), i.e. circular white mycelial patches 1 to 2 mm in diameter on the upper surface of the leaves, which coalesced and developed into larger circular or irregular spots on both leaf surfaces. Infected leaves dried and eventually dropped. Conidiophores were 110-220×11-13.5 µm in size and produced 3 to 5 immature conidia in chains with a crenate outline. Foot cells were 40-75 µm long, straight, cylindrical, slightly constricted at the basal septum. Conidia were hyaline, ellipsoid-ovoid, 25-40×17-22 µm in size and had distinct fibrosin bodies. These morphological traits suggested this fungus to be a species of the genus Podosphaera, likely corresponding to Podosphaera xanthii (Braun and Cook, 2012). For confirmation, the internal transcribed spacer (ITS) region of rDNA from conidia was amplified with primers ITS 1/ ITS 4 and sequenced according to Babu et al. (2015). The resulting 182 bp sequence (GenBank accession No. KU376473) was analysed by BLAST homology search against GenBank database revealing 100% similarity with P. xanthii (KX061106, KR779870). Pathogenicity was determined by inoculating conidial suspension onto young leaves of five healthy potted L. siceraria in a greenhouse at 25-28oC (>80% humidity). Five non inoculated plants served as control. Symptoms like those shown in the field developed 5-7 days post inoculation only on inoculated plants from which P. xanthii was reisolated. To our knowledge, this is the first report of P. xanthii as the cause of powdery mildew disease on bottle gourd in India.

Control and yield loss modelling of circular leaf spot of persimmon caused by Mycosphaerella nawae

ABSTRACTSymptoms of circular leaf spot of persimmon (CLSP), caused by Mycosphaerella nawae, consisted of necrotic spots on leaves, chlorosis and premature defoliation. Although CLSP is a foliar disease, early fruit maturation and abscission are frequently associated with the presence of lesions on leaves and defoliation, resulting in severe economic losses. Despite their importance for the design of efficient disease management programmes, quantitative relationships between CLSP incidence and yield loss are unknown. Therefore, fungicide efficacy trials were conducted during two consecutive years in Spain to induce different levels of disease severity, defoliation and yield loss. The effects of fungicide treatments on CLSP severity were analysed by ordinal logistic regression models. Relative yield loss values were regressed against the percentage of affected leaves or defoliated obtained at different evaluation dates. The disease had high negative impact and complete yield loss was observed in the absence of effective fungicide treatments. Preventive applications of pyraclostrobin, trifloxy‐strobin and mancozeb provided the best disease control and highest yields, up to 95.77 kg tree−1. An exponential relationship of CLSP incidence and defoliation with yield loss was found. In general, model fit and predictive ability was superior when defoliation, rather than incidence, was used as explanatory variable. The impact of defoliation on yield loss was higher in earliest evaluation dates, suggesting that early leaf abscission may be the main factor contributing to premature fruit drop and subsequent yield loss. Substantial yield losses were observed even with relatively low levels of CLSP incidence and defoliation. Therefore, it was not possible to define a critical action threshold for CLSP management based on foliar symptoms.

Nested PCR–based Assay for Diagnosis of Circular Leaf Spot Disease–causing Mycosphaerella nawae and its Application

Nested PCR–based Assay for Diagnosis of Circular Leaf Spot Disease–causing Mycosphaerella nawae and its Application

MR Imaging of Individual Perfusion Reorganization Using Superselective Pseudocontinuous Arterial Spin-Labeling in Patients with Complex Extracranial Steno-Occlusive Disease.

Patients with multiple stenoses or occlusions of the extracranial arteries require an individualized diagnostic approach. We evaluated the feasibility and clinical utility of a novel MR imaging technique for regional perfusion imaging in this patient group. Superselective pseudocontinuous arterial spin-labeling with a circular labeling spot enabling selective vessel labeling was added to routine imaging in a prospective pilot study in 50 patients (10 women, 70.05 ± 10.55 years of age) with extracranial steno-occlusive disease. Thirty-three had infarct lesions. DSC-MR imaging was performed in 16/50 (32%), and cerebral DSA, in 12/50 patients (24%). Vascular anatomy and the distribution of vessel stenoses and occlusions were defined on sonography and TOF-MRA. Stenoses were classified according to the NASCET criteria. Infarct lesions and perfusion deficits were defined on FLAIR and DSC-MR imaging, respectively. Individual perfusion patterns were defined on the superselective pseudocontinuous arterial spin-labeling maps and were correlated with vascular anatomy and infarct lesion localization. The superselective pseudocontinuous arterial spin-labeling imaging sequence could be readily applied by trained technicians, and the additional scan time of 12.7 minutes was well-tolerated by patients. The detected vessel occlusions/stenoses and perfusion patterns corresponded between cerebral DSA and superselective pseudocontinuous arterial spin-labeling maps in all cases. Perfusion deficits on DSC-CBF maps significantly correlated with those on superselective pseudocontinuous arterial spin-labeling maps (Pearson r = 0.9593, P < .01). Individual collateral recruitment patterns were not predictable from the vascular anatomy in 71% of our patients. Superselective pseudocontinuous arterial spin-labeling is a robust technique for regional brain perfusion imaging, suitable for the noninvasive diagnostics of individual perfusion patterns in patients with complex cerebrovascular disease.

Stepwise dynamics of an anionic micellar film – Formation of crown lenses

We studied the stepwise thinning of a microscopic circular foam film formed from an anionic micellar solution of sodium dodecyl sulfate (SDS). The foam film formed from the SDS micellar solution thins in a stepwise manner by the formation and expansion of a dark spot(s) of one layer less than the film thickness. During the last stages of film thinning (e.g., a film with one micellar layer), the dark spot expansion occurs via two steps. Initially, a small dark circular spot inside a film of several microns in size is formed, which expands at a constant rate. Then, a ridge along the expanding spot is formed. As the ridge grows, it becomes unstable and breaks into regular crown lenses, which are seen as white spots in the reflected light at the border of the dark spot with the surrounding thicker film. The Rayleigh type of instability contributes to the formation of the lenses, which results in the increase of the dark spot expansion rate with time. We applied the two-dimensional micellar-vacancy diffusion model and took into consideration the effects of the micellar layering and film volume on the rate of the dark spot expansion [Lee et al., 2016] to predict the rate of the dark spot expansion for a 0.06M SDS film in the presence of lenses. We briefly discuss the Rayleigh type of instability in the case of a 0.06M SDS foam film. The goals of this study are to reveal why the crown lenses are formed during the foam film stratification and to elucidate their effect on the rate of spot expansion.

Effect of the Hydric Factor and Arbuscular Mycorrhizal Fungi (AMF) on the Severity of &amp;lt;i&amp;gt;Phytophthora colocasiae&amp;lt;/i&amp;gt;

Colocasia esculenta (L.) Schott is an important food for millions of people in countries of Africa, Asia and Central America. The cultivation of taro suffers from an epidemic disease, the taro mildew, caused by P. colocasiae, which is a disease that manifests itself as oily and circular spots on tubers, stems, petioles and on taro leaves causing losses of more than 50% in less than ten days. This study was carried out to evaluate the impact of this pathogen on the leaf area parameter in two varieties of taro (Ibo coco and Atangana) at different water levels, then evaluate the incidence of the disease severity on the leaves at different water levels and study the behavior of this pathogen on plants previously inoculated with arbuscular mycorrhizal fungi (AMF) of the genus Gigaspora magarrita and Acaullospora tuberculata. The plants were separated into three batches (control batch not infected, batch infected with pathogen and batch not only infected but also inoculated with AMF at different water contents (500 ml, 370 ml, 250 ml and 125 ml), the batch infected with the pathogen alone showed a reduction in the growth parameters compared to the control, and the inoculated and infected batch also showed a reduction in growth parameters but closer to the control. In addition, the speed of propagation of the lesion in the inoculated batch is reduced compared to that of the uninoculated batch, and this speed also decreases with the water content, as a result of which the mildew of taro develops easily. Moreover, the addition of AMF makes it possible to minimize its propagation.

Doppler imaging of chemical spots on magnetic Ap/Bp stars

Doppler imaging (DI) is a powerful spectroscopic inversion technique that enables conversion of a line profile time series into a two-dimensional map of the stellar surface inhomogeneities. In this paper we investigate the accuracy of chemical abundance DI of Ap/Bp stars and assess the impact of several different systematic errors on the reconstructed spot maps. We simulate spectroscopic observational data for different spot distributions in the presence of a moderately strong dipolar magnetic field. We then reconstruct chemical maps using different sets of spectral lines and making different assumptions about line formation in the inversion calculations. Our numerical experiments demonstrate that a modern DI code successfully recovers the input chemical spot distributions comprised of multiple circular spots at different latitudes or an element overabundance belt at the magnetic equator. For the optimal reconstruction the average reconstruction errors do not exceed ~0.10 dex. The errors increase to about 0.15 dex when abundance distributions are recovered from a few and/or blended spectral lines. Ignoring a 2.5 kG dipolar magnetic field in chemical abundance DI leads to an average relative error of 0.2 dex and maximum errors of 0.3 dex. Similar errors are encountered if a DI inversion is carried out neglecting a non-uniform continuum brightness distribution and variation of the local atmospheric structure. This series of numerical DI simulations proves that inversions with simplifying assumptions of the non-magnetic radiative transfer and a single model atmosphere are generally reliable. We assess magnetic field strengths of several dozen Ap/Bp stars previously studied with DI methods, concluding that the vast majority of the published chemical spot maps are unaffected by the systematic errors addressed in this paper. (Abridged)

FIRST REPORT OF CLADOSPORIUM OXYSPORUM CAUSING LEAF SPOT OF ROSA INDICA IN PAKISTAN

In December 2014, necrotic leaf spots were observed on more than fifty rose ( Rosa indica ) plants in a private garden at Lahore, Pakistan, all showing the same symptoms The infected plants were 1-2 year old and on an average 90% of the leaves were covered with 2-5 mm circular black spots, with irregu- lar margins without chlorosis around the margins. Initially, infected leaves remained attached to the plants but dropped when the spots coalesced and covered more than 80% leaf area. No symptoms were observed on flowers. For pathogen isolation, one spot per leaf from six symptomatic leaves of dif- ferent plants were cut into pieces, surface sterilized, inoculated on 2% malt extract agar (MEA) and incubated at 25 ± 2oC. Morphological observations were made on 7-day-old pure cul- tures. Colonies were greenish black and attained the diameter of 4 mm. Conidiophores were macronematous, smooth walled, up to 500μm long and 4-5μm wide, with intercalary and termi- nal swellings. Conidia were pale brown arising from terminal swelling of conidiophores, in the form of simple or branched chains. Conidia were spherical, subspherical or limoniform, 3-6 μm in diameter; ramoconidia were 2-4×7-3 μm in size. A representative pure culture of the fungus was deposited to First Fungal Culture Bank of Pakistan under the accession No.FCBP1517. Based on morphology, the fungus was identi- fied as Cladosporium oxysporum (Bensch et al ., 2010). For se- quencing of ITS region, a DNA fragment of ca . 600 bp was amplified using universal primer pair ITS1/ITS4 and total ge- nomic DNA as template. BLASTn results indicated that ITS nucleotide sequence of this strain (KT283681) had 99% simi- larity with many other isolates of C . oxysporum in GenBank, including KT936546, LC040920, KJ475816 and JQ775499. Pathogenicity test was performed three times on young pot- ted rose plants using two different isolates. Since the inoculum of this fungus persists in soil, conidia from pure cultures were suspended in sterilized water (10 7 spores/ml) and sprayed in the soil of three healthy plants; three control plants were treated similarly with sterilized water. All plants, covered with poly- thene bags, were kept in a growth chamber at 23 ± 2oC. Ne- crotic spots similar to those described above started appearing on leaves only on inoculated plants after 21 days of incubation. Re-isolation of same fungus fulfilled Koch’s postulates. To our knowledge, this is the first report of R . indica leaf spot caused by C . oxysporum in Pakistan.

Comparison of Titanium Metal Matrix Composite Surface Layers Produced During Laser Gas Nitriding of Ti6Al4V Alloy by Different Types of Lasers

Abstract The article presents the results of a comparative study of the nitriding process of titanium alloy substrate using two lasers with different characteristics of laser beams. One of the applied lasers was a high power diode laser emitting at a dominant wavelength of 808 nm, with a rectangular laser beam spot, and multimode energy distribution across the spot. The second laser was a solid state Yb:YAG disk laser emitting at a wavelength of 1.03 μm, with a circular beam spot, characterized by near Gaussian energy distribution across the spot. In a case of both lasers single stringer beads with a similar width and at similar energy input were produced. As a result of melting of the substrate with a laser beam in a pure gaseous nitrogen atmosphere composite surface layers with in situ precipitated titanium nitrides embedded in the metallic matrix of titanium alloy were produced, in both cases. However, the surface topography and structure is different for the surface layers produce by different lasers at the same processing parameters and width of laser beams.

Taxonomic revision of Stagmatoptera Burmeister, 1838 (Mantodea: Mantidae, Stagmatopterinae).

Stagmatoptera Burmeister, 1838 includes medium to large-sized (49.8-98.7mm) praying mantises distributed in the Neotropical region. They are characterized for having a central, circular spot on each forewing, and 2-4 carinae in the head's frontal shield. This study is an updated revision of the genus on the basis of type and non-type material deposited in various scientific collections from Europe and the Americas. The following nomenclatural procedures were conducted: Stagmatoptera nova is a new junior synonym of Stagmatoptera pia, Stagmatoptera ignota as the junior synonym of Stagmatoptera femoralis, and Stagmatoptera flavipennis is reinstated as the junior synonym of Stagmatoptera supplicaria. Two new species are described: Stagmatoptera diana Rodrigues sp. n. from Colombia and Venezuela, and Stagmatoptera cerdai Rodrigues sp. n. from Trinidad & Tobago and Venezuela. Stagmatoptera now includes 14 species, two of which (Stagmatoptera abdominalis and Stagmatoptera indicator) are considered as species inquirenda. We provide detailed morphological descriptions of all species, a species-level identification key, in addition to abundant visual material to assist identification. Female genitalia, a structure seldom used for taxonomic purposes, was a useful character system to distinguish among species of the genus. Distribution maps for all species are also provided.

PH-responsive cholesteric liquid crystal double emulsion droplets prepared by microfluidics

Functionalized cholesteric liquid crystal (CLC) double emulsion droplets (DEDs) were prepared from nematic LCs of MLC-2132 doped with (S)-4-cyano-4′-(2-methylbutyl)biphenyl (CB15) by using a microfluidic method, employing glass capillaries with a combined co-flow and flow-focusing geometry. Both planar (P) and homeotropic (H) anchoring on the surfaces of the CLC DEDs could be achieved using poly(vinyl alcohol) (PVA) and a mixture of sodium dodecyl sulfate (SDS)/polysorbate 80 (TWEEN 80), respectively. The H configuration was unstable when used with SDS alone, and hence required the use of a mixture of SDS and TWEEN 80. The P/P, P/H, H/P, and H/H configurations on the inner/outer surfaces exhibited different surface morphologies, which were observed in reflection-mode bright-field image patterns. The P/P configuration displayed a distinct, circular central spot with a reflection color that represented the helical pitch of the CLC, since the planar orientation of the mesogenic groups caused a parallel orientation of helical layers relative to the droplet surface, (which meets the Bragg reflection condition). The P/H, H/P, and P/P images observed from the same mode exhibited small, black circular spots assembled in a pseudo-hexagonal fashion, with reflected colored light coming from the boundary regions between the circular spots. This result indicated that the small, circular spots were due to the perpendicular orientation of the helical layers that resulted from the homeotropic orientation of the mesogenic groups (which does not meet the Bragg reflection condition). The CLC DEDs coated with poly(acrylic acid)-b-poly(4-cyanobiphenyl-4′-oxyundecylacrylate) (PAA-b-LCP) on the outer surface (CLC DEDPAA) were pH-responsive. When the inner surface was controlled to have a P configuration with water, the central, circular reflection color pattern changed to a small, black circular spot pattern with increasing pH. This indicated that protonation and deprotonation of the carboxylic group of PAA occurred, which in turn led to planar (tangential) and perpendicular (homeotropic) orientations, respectively. These pH-sensitive, mono-dispersed CLC DEDs have potential use as biosensors, where immobilization of the ligands causes local changes in pH in response to analytes.

Demonstration of acoustic holographic rendering with two-dimensional metamaterial-based passive phased array

Acoustic holograms in analogy with optical holograms are useful for a variety of applications, such as multi-focal lensing, multiplexed sensing and synthesizing three-dimensional complex sound fields. We previously presented the designs and simulation results of several metamaterial-based acoustic holograms (J. Acoust. Soc. Am. 138, 1751 (2015)). Here, we demonstrate the experimental realization of two of them: one projects a complex pattern on the image plane, while the other focus energy onto multiple circular spots of different sizes. We showcase the holographic reconstruction measurements carried out in an anechoic chamber. The demonstrated passive holograms, without phase-shifting circuitry and transducer arrays, are advantageous for applications where simplicity, robustness, and small footprint are preferred over adaptive control. We also discuss the higher frequency versions of such holograms and their applications in robotic sensing and wireless power transfer. Such metamaterial-based holograms can serve as versatile platforms for various advanced acoustic wave manipulation and signal modulation, leading to new possibilities in acoustic sensing, imaging and energy deposition.

Tuning to a particular acoustic whispering-gallery mode in the GHz range

Surface Acoustic Waves (SAWs) generated with sub-picosecond light pulses are commonly used in non-destructive testing. The absorption of pump light by the medium generates SAWs that are detected by delayed probe light pulses. The spatiotemporal evolution of the SAWs can be imaged by scanning the position and time delay of the focused probe light pulses. Commonly used setups show two main constraints: the pump light is focused to a circular spot that generates SAWs in all directions, which does not allow control of directionality, and the laser repetition rate frep limits accessible frequencies to nfrep (n = 1,2,…). In the case of laser excitation and detection of whispering-gallery modes (WGM) on a disc, only certain frequencies are detectable, and counter-propagating modes cannot be separately excited. Here, we overcome these limitations in experimental GHz SAW imaging of WGMs. To access arbitrary frequencies, we periodically modulate in intensity of the pump and probe beams and make use of both in-phase and in-quadrature lock-in detection [1]-[3]. To generate WGMs propagating in a single direction, we make use of a spatial light modulator and computer-generated holograms. These new results extend the possibilities of SAW imaging by allowing fine control of excited surface acoustic modes. [1] S. Kaneko, M. Tomoda, and O. Matsuda, AIP Adv. 4, 017124 (2014); [2] O. Matsuda et al., IEEE Trans. Ultrason. Ferroelectr. Freq. Control 62, 584-595 (2015); [3] S. Mezil et al., Opt. Lett., 40, 2157-2160 (2015).

Deastigmatism, circularization, and focusing of a laser diode beam using a single biconvex microlens

A single biconvex microlens is proposed to correct the astigmatism and ellipticity of a laser diode (LD) beam and focus it to a smallest circular spot. The microlens has three different profiles in which one cylindrical input surface is to collimate the beam in the fast-axis (y-axis) direction. Output surface, on the other hand, holds two different parabolic profiles in fast- and slow-axis (x-axis) directions to correct the astigmatism and focus the beam into a smallest circular spot. A simulation software is used to design and optimize those lens profiles. Theoretically, the smallest focused spot size is around 4.24 μm in diameter. The three profiles are then transferred to photo-masks to fabricate the microlens on polycarbonate material using an excimer laser dragging method with alignment accuracy of 1 μm. The machined microlens is assembled with the LD using double-sided optically clear adhesive tape. The experimental focused spot is found to be 16.75 μm in diameter. Circularity of the focused spot is demonstrated by a single-shot exposure test on thin photoresist layer that shows a circular-dot diameter of 7.32 μm. The proposed technique has great potential in applications such as beam pen lithography, fiber coupling, and optical read-write head.

First Report of Leaf Spot Caused by Alternaria tenuissima on Black Chokeberry (Aronia melanocarpa) in Korea

In July 2015, diseased leaves of black chokeberry (Aronia melanocarpa) were observed in Danyang and Gochang, Korea. The symptoms appeared as circular or irregular brown leaf spots, from which Alternaria tenuissima was isolated. The isolates were cultured on potato dextrose agar, and their morphological characteristics were observed under a light microscope. The colonies were whitish to ash colored. The pathogenicity test on healthy black chokeberry leaves produced circular brown spots, in line with the original symptoms. Molecular analyses of the ITS, GPD, RPB2, and TEF genes were conducted to confirm the identity of the pathogen. The phylogeny of the multi-gene sequences indicated that the causal agent was A. tenuissima. This study is the first report of A. tenuissima leaf spot on black chokeberry (A. melanocarpa).

Optical Inspection and Morphological Analysis of Diospyros kaki Plant Leaves for the Detection of Circular Leaf Spot Disease.

The feasibility of using the bio-photonic imaging technique to assess symptoms of circular leaf spot (CLS) disease in Diospyros kaki (persimmon) leaf samples was investigated. Leaf samples were selected from persimmon plantations and were categorized into three groups: healthy leaf samples, infected leaf samples, and healthy-looking leaf samples from infected trees. Visually non-identifiable reduction of the palisade parenchyma cell layer thickness is the main initial symptom, which occurs at the initial stage of the disease. Therefore, we established a non-destructive bio-photonic inspection method using a 1310 nm swept source optical coherence tomography (SS-OCT) system. These results confirm that this method is able to identify morphological differences between healthy leaves from infected trees and leaves from healthy and infected trees. In addition, this method has the potential to generate significant cost savings and good control of CLS disease in persimmon fields.

Design of Hartmann type null screens for testing a plano-convex aspheric lens with a CCD sensor inside the caustic.

A new method to design Hartmann type null screens to test either qualitatively or quantitatively fast plano-convex aspherical lenses is presented. We design both radial and square null screens that produce arrays of circular spots uniformly distributed at predefined planes, considering that the CCD sensor is solely placed inside the caustic region. The designs of these null screens are based on knowledge of the caustic by refraction and on exact ray tracing. The null screens also serve to improve the alignment in optical systems.

Biosynthesis and Biomedical Applications of Gold Nanoparticles Using Eclipta prostrata Leaf Extract

This study reports the biological synthesis of gold nanoparticles (AuNPs) by the reduction of HAuCl4 by using of Eclipta prostrata leaf extract as the reducing and stabilizing agent. AuNPs were characterized using Ultraviolet–visible (UV-vis) spectroscopy, X-ray diffraction (XRD), Fourier Transform-Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), High Resolution-Transmission Electron Microscopy (HRTEM), and Energy Dispersive X-ray analysis (EDAX). The UV-visible spectrum of the synthesized AuNPs showed surface plasmon resonance (SPR) around 534 nm. The face-centered cubic (FCC) structure of the AuNPs was confirmed by XRD peaks at 38.10°, 44.13°, 64.43°, and 77.32°, which correspond to (111), (200), (220), and (311) miller indices, respectively, with clear circular spots in the selected area electron diffraction (SAED). FTIR measurements showed the AuNPs having a coating of phenolic compounds, indicating a possible role of biomolecules responsible for capping and efficient stabilization of the AuNPs. The HRTEM images determined the particles are spherical, hexagonal, and triangular in shape, with an average size of 31 ± 1.6 nm. The synthesized AuNPs show good antibacterial, antioxidant, and cytotoxic activity. The outcomes of this study indicate that these nanoparticles could be effectively utilized in pharmaceutical, biotechnological, and biomedical applications.