Parasitic Effects Research Articles

Parasites as potential targets for cancer immunotherapy.

Parasites and cancers have some common antigens. Much scientific evidence in the human population, animal models, and in vitro experiments exhibit that parasites have significant anti-cancer effects. The larval stage of the tapeworm Echinococcus granulosus, Toxoplasma gondii, Trypanosoma cruzy, Plasmodium's, and Trichinella spiralis are among the parasites that have been subjects of anti-cancer research in the last decades. Anti-tumor effects of parasites may be due to the direct impact of the parasites per se or indirectly due to the immune response raised against common antigens between malignant cells and parasites. This manuscript reviews the anti-cancer effects of parasites and possible mechanisms of these effects. Options for using parasites or their antigens for cancer treatment in the future have been discussed.

Improved Q-Factor 3D Double-Layered On-Chip Resistor with Shielded Ground Conductor

In this paper, a double-layered structure to form an N-Well meander-line structure by added shielding grounded conductor to improve the quality factor on-chip resistors in high frequency operation is presented. An additionally added shielding ground conductor is applied to the proposed structure to reduce the induced capacitance coupling. and substrate losses for further improvement of the Q factor were also presented. Sonnet EM simulation result validated that double-layered structure via the shielding ground conductor was effective to improve their quality factors by 37.8% from 1.209 to –0.752 and reducing capacitance coupling effect by 57.92% from 55.23fF to 23.24fF during operating frequency at 10 GHz compared with conventional N-Well meander-line resistors. A novel structure in the design of a double-layered on-chip resistor with a shielding grounded conductor showed that capacitance coupling of parasitic effect was reduced; therefore, a low Q factor in high-frequency operations was obtained.

Design and Implementation of a Paralleled Discrete SiC MOSFET Half-Bridge Circuit with an Improved Symmetric Layout and Unique Laminated Busbar

Silicon carbide (SiC) metal oxide semiconductor field effect transistors (MOSFETs) have many advantages compared to silicon (Si) MOSFETs: low drain-source resistance, high thermal conductivity, low leakage current, and high switching frequency. As a result, Si MOSFETs are replaced with SiC MOSFETs in many industrial applications. However, there are still not as many SiC modules to customize for each application. To meet the high-power requirement for custom applications, paralleling discrete SiC MOSFETs is an essential solution. However, it comes with many technical challenges; inequality in current sharing, different switching losses, different transient characteristics, and so forth. In this paper, the detailed MATLAB®/Simulink® Simpscape model of the SiC MOSFET from the datasheet and the simulation of the half-bridge circuit are investigated. Furthermore, this paper proposes the implementation of the four-paralleled SiC MOSFET half-bridge circuit with an improved symmetric gate driver layout. Moreover, a unique laminated busbar connected directly to the printed circuit board (PCB) is proposed to increase current and thermal capacity and decrease parasitic effects. Finally, the experimental and simulation results are presented using a 650 V SiC MOSFET (CREE) double-pulse test (DPT) circuit. The voltage overshoot problems and applied solutions are also presented.

Tachinid parasitoid Exorista japonica affects the utilization of diet by changing gut microbial composition in the silkworm, Bombyx mori

Changes in both intake and digestion of feed have been demonstrated in the host following parasitization. However, its regulatory mechanism has not been clarified. In this study, silkworms and Exorista japonica were used as research objects to analyze the effect of parasitism on the midgut immune system of the silkworm. After being parasitized, the expressions of antimicrobial peptide (AMP) genes of silkworms showed a fluctuating trend of first upregulation and then downregulation, while phenoloxidase and lysozyme activities were inhibited. To study the possible impact of the downregulation of AMP genes on intestinal microorganisms, the characteristics of the intestinal microbial population of silkworms on the third day of parasitism were analyzed. The relative abundance of Firmicutes, Proteobacteria, and Bacteroidota decreased, while that of Actinobacteriota increased. The increased abundance of conditionally pathogenic bacteria Serratia and Staphylococcus might lead to a decrease in the amount of silkworm ingestion. Meanwhile, the abundance of Acinetobacter, Bacillus, Pseudomonas, and Enterobacter promotes an increase in the digestion of nutrients. This study indicated that the imbalance of intestinal microbial homeostasis caused by parasitism may affect the absorption and digestion of nutrients by the host. Collectively, our findings provided a new clue for further exploring the mechanism of nutrient transport among the host, parasitoid, and intestinal microorganisms.

Hybrid small-signal model parameter extraction for GaN HEMT based on QGA

ABSTRACT A novel algorithm is proposed for optimal extraction of GaN HEMT small-signal model parameters. The proposed Quantum Genetic Algorithm (QGA) exploits the superposition, entanglement and interference of quantum states, which solves the problems of high number of iterations and slow convergence when obtaining optimal solutions using Genetic Algorithms (GA). Meanwhile, it is solved that the Particle Swarm Optimisation (PSO) algorithm produces premature convergence and easily falls into the local optimum solution. In order to avoid the influence of distributed parasitic effects in large size devices under high-frequency conditions, a suitable frequency range is determined and combined with direct extraction techniques to determine the range of parameter values. The model parameter values are optimised step by step using QGA. In order to verify the superiority of QGA, QGA and PSO algorithms are both used to optimise GaN HEMT small-signal model parameters. By comparing the modelled S-parameter effects of the QGA and the PSO algorithm, it can be found that the QGA has better consistency with the measured data.

Effects of parasitism by the braconid wasp, Bracon hebetor (Hymenoptera: Braconidae), on the host hemolymph and phenoloxidase activation of the rice moth, Corcyra cephalonica larvae (Lepidoptera: Pyralidae)

BackgroundBiological control of insect pests is an economic, eco-friendly and harmless approach to integrated pest management strategies. Bracon hebetor (Say) (Hymenoptera: Braconidae) considers a polyphagous ectoparasitoid of various pests of the order Lepidoptera. The parasitized host insects' defense mechanisms are triggered as a result of the parasitic wasps' injury and penetration. Thus, induce the host cellular and humoral immune responses through a blend of secretions injected into the host body. The present study was designed to evaluate the efficacy of B. hebetor on the immune response of the parasitized full grown larval instar of the rice moth, Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) under natural envenomation.ResultsOn cellular level, the ultrastructure examination of the hemocytes displayed a considerable structural deformation in hemocyte morphology of the detected types of the hemocytes. Moreover, the effects of parasitism on both differential hemocyte counts (DHCs) and total hemocyte counts (THCs) were investigated. The number of prohemocytes (PR) (40.33 ± 5.61, 43 ± 8.33 and 26 ± 2.31) was statistically differed after (24, 48 and 72 h) of parasitism, respectively, compared to unparasitized (31.33 ± 6.49) larvae. Similar observations were recorded in plasmatocytes (PL) before and after the parasitism. However, Spherulocytes (SP) and Oenocytoids (OE) were recorded in the hemolymph with little abundance. On the other side, the quantitative analysis of total hemolymph proteins (THP) provoked a significant effect of considering parasitized and non-parasitized larvae. As the Phenoloxidase (PO) cascade plays a critical role in immune defenses, so the substantial activation of PO in the host's hemolymph following successive hours of parasitism compared to unparasitized larvae using L-DOPA as a substrate indicated the induction of larval immune system. The parasitized larvae showed a gradual increase in the PO activity (0.442 ± 0.103) after 24 h reached up to (1.482 ± 0.272) at the end of parasitism (72 h) in comparable to unparasitized larvae (0.177 ± 0.0.044).ConclusionThe present investigations clarified the efficacy of B. hebetor parasitism on the host immune mechanism, which will enable the progress of sustainable stored product protection approaches for the control of an important pest rice moth C. cephalonica.

Adverse effects of synergic factors at play during intestinal parasitism in pregnancy

Intestinal parasitism is a widely extended public health problem, causing significant morbidity and disabilities. It is well documented that pregnancy, with its increased nutritional demands and altered immune defenses, is an especially vulnerable time to contract intestinal parasitism. By affecting the health of both mothers and their progeny, those parasite infections are a double burden for pregnant women, who often experience more severe intestinal parasitism than their non-pregnant counterpart. It should be taken into account that in this health problem concur synergistically factors related to parasites, the physiological peculiarities of the pregnant women and the socioeconomic scenario in which they live. Despite the adverse effects of intestinal parasitism on pregnancy, fetuses, and newborns, its worldwide prevalence, and the associated risk factors, among pregnant women are little known. In spite of this, with the information available today, it is possible to sustain that the prevalence of intestinal parasitism among pregnant women is greater in by low and middle income countries. As we argue in the text of this document, intestinal parasite infections constitute an underestimated public health problem among pregnant women and their offspring and, accordingly, we opine that their diagnosis, treatment, and control require more attention.

Factors influencing short-term parasitoid establishment and efficacy for the biological control of Halyomorpha halys with the samurai wasp Trissolcus japonicus.

Classical biological control has been identified as the most promising approach to limit the impact of the invasive pest species Halyomorpha halys (Heteroptera: Pentatomidae). This study investigated the parasitism rate at sites where the biocontrol agent Trissolcus japonicus (Hymenoptera: Scelionidae) was released and where its unintentional introduction took place, in the Trentino-South Tyrol region. The effect of land-use composition was studied to understand which factors favor the establishment of hosts and parasitoids, including native and exotic species. The released T.japonicus were detected a year after the start of the program, with a significant parasitoid impact and discovery, compared to control sites. Trissolcus japonicus was the most abundant H.halys parasitoid, and Trissolcus mitsukurii and Anastatus bifasciatus were recorded also. The efficacy of T.mitsukurii was lower in sites where T.japonicus was successfully established, suggesting a possible competitive interaction. Parasitism level by T. japonicus at the release sites was 12.5% in 2020 and 16.4% in 2021. The combined effect of predation and parasitization increased H.halys mortality up to 50% at the release sites. Landscape composition analysis showed that both H.halys and T.japonicus were more likely to be found at sites with lower altitude and with permanent crops, whereas other hosts and parasitoids preferred different conditions. Trissolcus japonicus showed a promising impact on H.halys, at release and adventive sites, with minor nontarget effects, mediated by landscape heterogeneity. The prevalence of T.japonicus in landscapes with permanent crops could support IPM in the future. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Single VDGA-Based Mixed-Mode Electronically Tunable First-Order Universal Filter.

This article presents a mixed-mode electronically tunable first-order universal filter configuration employing only one voltage differencing gain amplifier (VDGA), one capacitor, and one grounded resistor. With the appropriate selection of the input signals, the proposed circuit can realize all three first-order standard filter functions, namely low pass (LP), high pass (HP), and all pass (AP), in all four possible modes, including voltage mode (VM), trans-admittance mode (TAM), current mode (CM), and trans-impedance mode (TIM), from the same circuit structure. It also provides an electronic tuning of the pole frequency and the passband gain by varying transconductance values. Non-ideal and parasitic effect analyses of the proposed circuit were also carried out. PSPICE simulations and experimental findings have both confirmed the performance of the design. A number of simulations and experimental observations confirm the viability of the suggested configuration in practical applications.

Survey and Prevalence of Lice Infestation the Pigeons (Columba livia domestica) in Kurdistan Region-Iraq

Many parasite species may damage domestic pigeons, which are from the most essential birds for human populations in every corner of the world. Ectoparasites can be found in almost every bird. Birds can be impacted by a number of health problems, but parasitic illnesses play a crucial role influence. They are a significant source of disease infection and transmission. Although domestic pigeon lice are not known to spread any avian infections, they are hazardous to young birds in particular and typically accompany poor poultry health that is due to other factors. where a lot of lice could keep you up at night. They consume their bodily fluids, such as blood, and feathers. Since lice have a chewing mouthpart and feed on dry skin scales, scab tissues, and feather parts in addition to irritating the host's skin and sucking blood, the effects of louse parasitism on birds are frequently severe and include stunted growth and susceptibility to other infections. From October 2017 to July 2018, 200 domestic pigeons were checked for pigeons chewing lice. Three urban locations were chosen at random for each of the three main governorates in the study area—Duhok, Erbil, and Sulaymaniyah. Hands were picked clean of lice; Samples were kept in 96 percent ethanol-filled tubes before being examined and identified under a dissecting microscope. In the current study, 48% (96/200) of domestic pigeons were infected with one or more lice and three species of lice were recorded and identified by morphological characteristics: Companulatus compare, Columbicola columbae, and Hohorostilla lata.

O-011 Quantifying the effects of parasitism on lamb methane emissions

O-011 Quantifying the effects of parasitism on lamb methane emissions

From guest to host: parasite Cistanche deserticola shapes and dominates bacterial and fungal community structure and network complexity

BackgroundRhizosphere and plant microbiota are assumed to play an essential role in deciding the well-being of hosts, but effects of parasites on their host microbiota have been rarely studied. Also, the characteristics of the rhizosphere and root microbiota of parasites and hosts under parasitism is relatively unknown. In this study, we used Cistanche deserticola and Haloxylon ammodendron from cultivated populations as our model parasites and host plants, respectively. We collected samples from BULK soil (BULK), rhizosphere soil of H. ammodendron not parasitized (NCD) and parasitized (RHA) to study how the parasite influenced the rhizosphere microbiota of the host. We also collected samples from the rhizosphere soil and roots of C. deserticola (RCD and ECD) and Haloxylon ammodendron (RHA and EHA) to explore the difference between the microbiota of the parasite and its host under parasitism.ResultsThe parasite reduced the compositional and co-occurrence network complexities of bacterial and fungal microbiota of RHA. Additionally, the parasite increased the proportion of stochastic processes mainly belonging to dispersal limitation in the bacterial microbiota of RHA. Based on the PCoA ordinations and permutational multivariate analysis of variance, the dissimilarity between microbiota of C. deserticola and H. ammodendron were rarely evident (bacteria, R2 = 0.29971; fungi, R2 = 0.15631). Interestingly, four hub nodes of H. ammodendron in endosphere fungal microbiota were identified, while one hub node of C. deserticola in endosphere fungal microbiota was identified. It indicated that H. ammodendron played a predominant role in the co-occurrence network of endosphere fungal microbiota. Source model of plant microbiome suggested the potential source percentage from the parasite to the host (bacteria: 52.1%; fungi: 16.7%) was lower than host-to-parasite (bacteria: 76.5%; fungi: 34.3%), illustrating that microbial communication was bidirectional, mainly from the host to the parasite.ConclusionsCollectively, our results suggested that the parasite C. deserticola shaped the diversity, composition, co-occurrence network, and community assembly mechanisms of the rhizosphere microbiota of H. ammodendron. Additionally, the microbiota of C. deserticola and H. ammodendron were highly similar and shared. Our findings on parasite and host microbiota provided a novel line of evidence supporting the influence of parasites on the microbiota of their hosts.

Three-dimensional modeling and simulation of RF cavity for a transmitter with bandwidth of 40–100 MHz at 100-kilowatt level

A 1.5 MW final power amplifier is to be developed for ion cyclotron resonance heating (ICRH) system for the China fusion engineering testing reactor (CFETR) project. First, the feasibility of driver power amplifier with input matching circuit and output resonator cavity and a newly developed tetrode was cross-verified through three-dimensional (3D) simulations and experiments. A single coaxial cavity in parallel with the tetrode covered the frequency range of 40 to 100 MHz at a 100-kilowatt level. In contrast to the previous method of deducing matching parameters using RF circuit and transmission line theory, the use of 3D transmitter simulations provided more accurate matching parameters of tuning components at different operating frequencies. A new phenomenon of high frequency oscillation between the short strip inductor and the shield cavity was found in the input simulation results, which was subsequently verified by experiments. Specific reasons for dividing the output into two parts of high and low frequency were found through output circuit simulations. One is that the length of short stub decreases with the increase of operating frequency, thus decreasing the frequency resolution if all frequencies were using low frequency port. The other is that the coupling capacitor increases sharply with the increase of frequency due to parasitic effect in the low output. Further, the simulation facilitated the study of parasitic effects on matching parameters caused by strip-inductance, inter electrode capacitances of tetrode, and RF cavity. Thus, facilitating the design of final power amplifier in the future. Finally, the amplifier installed with the new tetrode DB968 achieved the design objectives in the test experiment with 150 and 110 kW power outputs at 48 and 100 MHz, respectively.

Parasitic masking effect in GaN SA-MOVPE using SiO2 masks deposited by the PECVD technique

The paper reports a phenomenon of parasitic substrate masking during selective area metalorganic vapor phase epitaxy (SA-MOVPE) of gallium nitride (GaN) using silicon dioxide (SiO2) masks deposited by plasma enhanced chemical vapor deposition (PECVD) at pressures above 150 hPa. The discussion of the thermal stability and nitridation process of the SiO2 films is followed by the presentation of the experimental work results focused on the investigation of the relationship between the parasitic masking effect and pressure in the MOVPE reactor chamber. Analysis of the surface morphology is conducted using scanning electron microscopy (SEM) and atomic force microscopy (AFM). A hypothesis was proposed explaining the formation of the deposition-free region that indicates silanimine (HNSi) layer formation as a possible factor responsible for the adverse inhibition of GaN nucleation.

PLF Design for DC-DC Converters Based on Accurate IL Estimations

Even though today’s electromagnetic compatibility (EMC) standards and measurement techniques set specific limitations and a clear methodology to measure the conducted emissions (CE) of equipment under tests (EUTs), the design methodology of a suitable power-line filter (PLF) to solve non-compliance is, in general, neither accurate nor efficient. This is due to different reasons, such as unknown actual load and line impedances, unknown dominant mode in the CE, and/or inappropriate instrumentation for the appropriate measurements. The objective of this paper is to investigate if different topologies of switching mode power supplies (SMPSs) lead to different PLF structures. For the sake of exemplification, the analysis is focused on switched-mode DC-DC converters. From an EMC point of view, these devices can be completely modeled by means of Scattering (S)–parameter and CE measurements. Additionally, an analysis of their circuit models has been performed to allow a better comprehension of their characterization. In this paper, the circuit models of three different types of DC-DC converters are presented, and their component values (including nonlinearities and parasitic effects introduced by the actual behavior of the circuit elements) are estimated using the S-parameter characterization. Then, a new methodology for PLF design, based on accurate insertion loss (IL) estimations, is applied to obtain the optimal PLF for one of the converters. This methodology is experimentally tested and validated.

Parental food provisioning and nestling growth under Philornis downsi parasitism in the Galapagos Green Warbler-Finch, classified as ‘vulnerable’ by the IUCN

In the Galapagos Islands, many endemic landbird populations are declining due to habitat degradation, food availability, introduced species and other factors. Given nestlings typically lack efficient defense mechanisms against parasites, hematophagous ectoparasites such as the larvae of the introduced Avian Vampire Fly, Philornis downsi, can impose high brood mortality and cause threatening population declines in Darwin finches and other landbirds. Here, we assess whether the food compensation hypothesis (i.e., the parents’ potential to compensate for deleterious parasite effects via increased food provisioning) applies to the Green Warbler-Finch. We differentiated nests with low or high infestation levels by P. downsi and quantified food provisioning rates of male and female parents, time females spent brooding nestlings, and nestling growth. Male provisioning rates, total provisioning rates and female brooding time did not significantly vary in relation to infestation levels, nor by the number of nestlings. Opposed to the predictions of the food compensation hypothesis, females showed significantly reduced provisioning rates at high infestation levels. Nestling body mass was significantly lower and there was a reduction of skeletal growth, although not significantly, in highly infested nests. The females’ response to high infestation may be due to parasites directly attacking and weakening brooding females, or else that females actively reduce current reproductive effort in favor of future reproduction. This life-history trade-off may be typical for Darwin finches and many tropical birds with long lifespans and therefore high residual reproductive value. Conservation strategies may not build on the potential for parental food compensation by this species.

Life history matters: Differential effects of abomasal parasites on caribou fitness

Parasites can impact wildlife populations through their effects on host fitness and survival. The life history strategies of a parasite species can dictate the mechanisms and timing through which it influences the host. However, unravelling this species-specific effect is difficult as parasites generally occur as part of a broader community of co-infecting parasites. Here, we use a unique study system to explore how life histories of different abomasal nematode species may influence host fitness. We examined abomasal nematodes in two adjacent, but isolated, West Greenland caribou (Rangifer tarandus groenlandicus) populations. One herd of caribou were naturally infected with Ostertagia gruehneri, a common and dominant summer nematode of Rangifer sspp., and the other with Marshallagia marshalli (abundant; winter) and Teladorsagia boreoarcticus (less abundant; summer), allowing us to determine if these nematode species have differing effects on host fitness. Using a Partial Least Squares Path Modelling approach, we found that in the caribou infected with O. gruehneri, higher infection intensity was associated with lower body condition, and that animals with lower body condition were less likely to be pregnant. In caribou infected with M. marshalli and T. boreoarcticus, we found that only M. marshalli infection intensity was negatively related to body condition and pregnancy, but that caribou with a calf at heel were more likely to have higher infection intensities of both nematode species. The differing effects of abomasal nematode species on caribou health outcomes in these herds may be due to parasite species-specific seasonal patterns which influence both transmission dynamics and when the parasites have the greatest impact on host condition. These results highlight the importance of considering parasite life history when testing associations between parasitic infection and host fitness.

Co-deposition of C and Ni[sbnd]P to fabricate high-ohmic resistor for board-level integration with on-line monitoring method

Embedding thin–film resistance (ETFR) in printed circuit boards (PCB) is of great significance for precise circuit designing and is thus widely applied in analogous circuits. This work introduces diethylenetriamine (DETA) into NiP electroless-plating solution to obtain C-doped NiP high-ohmic value resistor with square resistance over 400 Ω/sq. During the deposition, a referred resistor is monitored on-line to indicate the resistance of other embedded resistors, achieving a confined resistive error within ±10 %. This reduced resistive error primely satisfies the developing demand for the effective transmission of signal. The effects of DETA content, temperature and pH values on resistances were studied to optimize the Ni-P-C composition, yielding the highest ohm value of 731 Ω/sq. Rectangular and serpentine resistors with varied sizes were fabricated to confirm the realizability of this proposed method. The results of experiments including lamination processing and temperature coefficient of resistance (TCR) tests suggest the thermal as well as mechanical stability of the fabricated embedded resistor for PCB manufacture. The HFSS simulation for comparison between the parasitic effects of surface mounted technology resistor (SMTR) and ETFR indicates that the prominent performance of the developed resistor is compatible with ETFR components.

Valley Hall effect and kink states in topolectrical circuits

We investigate the emergence of topological valley Hall and kink states in a two-dimensional topolectrical (TE) model as a result of broken chiral and reflection symmetries. The TE system consists of two segments hosting distinct topological states with opposite (similar) signs of the valley Hall index, and separated by a heterojunction to exhibit valley kink (Chern insulating) phases at the interface. In the practical circuit, the valley Hall index can be flipped between the two segments by modulating the on-site potential on the sublattice nodes of the respective segments. The presence of grounding connections in the circuit array subsequently leads to the emergence of gapped and gapless valley and kink states in the admittance spectra. These topological modes can be detected electrically by the impedance readouts of the system, which can be correlated to its admittance spectra. Finally, we confirm the robustness of the valley Hall and kink states via realistic LTspice simulation, taking into account the tolerance windows and parasitic effects inherent in circuit components. Our study demonstrates the applicability of TE circuit networks as a platform to realize and tune valley-dependent and kink topological phenomena.

Analysis and optimization design of control signal line parasitic effects on streaking phenomenon in CMOS image sensor

This paper presents an optimization scheme for charge transfer control signal (TX) line to suppress the streaking phenomenon in CMOS image sensor (CIS) with FD-Shared. The influence of the streaking phenomenon in the image is evaluated by the increment of dark pixels. By building the mathematical model of streaking phenomenon, the relationship between the size of TX line and the increment of dark pixels is revealed. The simulation results show that for a 6.144 cm (H) × 8.192 cm (V) pixel array under 110 nm CMOS process, when the width of the TX line is 0.4 μm, the increment of dark pixels is the smallest. The minimum increment is 0.1709 DN at 0 dB and 2.7080DN at 24 dB. The increment is linearly amplified by the readout circuit gain. In the chip design, the streaking phenomenon can be alleviated according to the model analysis and optimization scheme given in the paper.