Plastic Petri Dishes Research Articles

Сравнительное исследование in vitro противовирусной активности эфирных масел и дезинфицирующих средств разных групп в отношении штаммов SARS-CoV-2 с различной вирулентностью

Introduction. To study the antiviral activity of essential oils against the SARS-CoV-2 virus, essential oils of conifers and other plants with known antimicrobial and antiseptic properties were studied. Comparative studies were conducted to study the antiviral activity of disinfectants of different groups widely used in practical healthcare, such as chloramine, formalin and ethyl alcohol, with the virucidal activity of selected essential oils against two strains of the SARS-CoV-2 virus with different virulence. Objectiv. To compare the antiviral activity of essential oils against selected strains of the SARS-CoV-2 coronavirus using the suspension method and the author’s method of contactless exposure, and to compare it with the antiviral activity of vapors of known disinfectants used to disinfect virological boxed rooms. Materials and methods. A comparative study of the antiviral activity of essential oils and disinfectants was carried out using the suspension method and the author’s non-contact exposure method specially developed for this study. Non-contact exposure method: the coronavirus viral suspension was applied to the surface of the lid of sterile plastic Petri dishes. Essential oils and disinfectants were applied to the inner surface of the bottom of the Petri dishes. After exposure to vapors of essential oils or disinfectants (without direct contact) on the SARS-CoV-2 viral suspension, swabs were taken from the surface of the Petri dish lid. The residual infectious activity of the SARS-CoV-2 virus was determined by TCD50/ml using the standard titration method in Vero E6 cell culture. Results. The results obtained during the studies using these methods showed that essential oils are capable of suppressing the infectious activity of the SARS-CoV-2 coronavirus. Essential oils of coniferous plants had the greatest antiviral ability. Essential oils of juniper, pine and tea tree had a fairly high antiviral effect, while essential oils of thyme, orange and clove had a moderate effect. Conclusion. Essential oils are effective disinfectants that can suppress the infectious activity of the studied strains of the SARS-CoV-2 coronavirus. Keywords: essential oils, antiviral activity, disinfectants, formalin, SARS-CoV-2 coronavirus.

Intake of imidacloprid in lethal and sublethal doses alters gene expression in Apis mellifera bees

Bees are important pollinators for ecosystems and agriculture; however, populations have suffered a decline that may be associated with several factors, including habitat loss, climate change, increased vulnerability to diseases and parasites and use of pesticides. The extensive use of neonicotinoids, including imidacloprid, as agricultural pesticides, leads to their persistence in the environment and accumulation in bees, pollen, nectar, and honey, thereby inducing deleterious effects. Forager honey bees face significant exposure to pesticide residues while searching for resources outside the hive, particularly systemic pesticides like imidacloprid. In this study, 360 Apis mellifera bees, twenty-one days old (supposed to be in the forager phase) previously marked were fed syrup (honey and water, 1:1 m/v) containing a lethal dose (0.081 μg/bee) or sublethal dose (0.00081 μg/bee) of imidacloprid. The syrup was provided in plastic troughs, with 250 μL added per trough onto each plastic Petri dish containing 5 bees (50 μL per bee). The bees were kept in the plastic Petri dishes inside an incubator, and after 1 and 4 h of ingestion, the bees were euthanised and stored in an ultra-freezer (−80 °C) for transcriptome analysis. Following the 1-h ingestion of imidacloprid, 1516 genes (73 from lethal dose; 1509 from sublethal dose) showed differential expression compared to the control, while after 4 h, 758 genes (733 from lethal dose; 25 from sublethal) exhibited differential expression compared to the control. All differentially expressed genes found in the brain tissue transcripts of forager bees were categorised based on gene ontology into functional groups encompassing biological processes, molecular functions, and cellular components. These analyses revealed that sublethal doses might be capable of altering more genes than lethal doses, potentially associated with a phenomenon known as insecticide-induced hormesis. Alterations in genes related to areas such as the immune system, nutritional metabolism, detoxification system, circadian rhythm, odour detection, foraging activity, and memory in bees were present after exposure to the pesticide. These findings underscore the detrimental effects of both lethal and sublethal doses of imidacloprid, thereby providing valuable insights for establishing public policies regarding the use of neonicotinoids, which are directly implicated in the compromised health of Apis mellifera bees.

Lethality of Simulated UV and Solar Diffuse Radiations to Detached Urediniopores of Phakopsora pachyrhizi

Asian soybean rust (ASR), caused by the fungus Phakopsora pachyrhizi, is the most destructive disease on the crop. This work aimed to generate data to understand the detached uredospores survival during the winter fallow in Mato Grosso state, Brazil. Experiment ‘A’—the detached urediniospores maintained and multiplied on Ativa soybean cultivar, were deposited on soybean estract-agar and kept at 25 oC temperature in closed plastic petri dishes and exposed to UV-C (100-280 nm) radiation, distant 30 cm from the plates surface for ‘ 0’; 60; 120; 180; 240; 300; 360, 420, 480 and 560 minutes. Experiment ‘B’—was similar to previous experiment but spores were exposed to UV-B (280-320 nm) radiation. In Experiment ‘C’—the urediniospores were deposited into empty plastic petri dishes without lids and exposed to direct diffuse sunlight for 0; 60; 120; 180; 240; 300; 360; 420; and 300 minutes. Solar radiation was measured with a pyranometer (Spectrum Technologies, Inc.). After the exposition time, urediniospores were plated on soybean-extract agar, incubated at 25 oC under dark for 8 h and germination assessed under an optical microscope (400‍×). Data were submitted to analyses of variance and regression. All experiments were repeated twice. The detached spores exposed to UV-C were killed with 496 minutes, and under UV-B radiation killed with 962.7 minutes and those submitted to direct diffusion solar radiation killed by 15.6 MJ m-2 dose, or 240 minutes exposition to 1,250 w/m2. It can be inferred that the incident solar diffused radiation in Mato Grosso, during the winter fallow, has the daily potential to kill the detached P. pachyrhizi urediniospores.

Electromagnetic Nature of Distant Interaction of the Atmospheric Pressure Helium Plasma Discharge Tube with Glioblastoma Cancer Cells.

Atmospheric pressure coaxial gaseous discharge tubes (DTs) with helium have demonstrated potential for in vitro inactivation or sensitization of glioblastoma cancer cells. Here, we study the effect of two configurations of the DT electrode system on its electromagnetic emissivity as well as other physical factors (heating and UV emission) that form in the vicinity of this device. We demonstrate that the configuration of the DT electrodes that concentrates the discharge streamers near the top of the device has a distant (cm scale) deactivation effect on U87-MG glioblastoma cancer cells when irradiated, without measurable UV components in the DT optical emission spectra. This effect persists even through different barriers such as glass, plastic, or quartz Petri dishes but is eliminated when glass or plastic dishes are filled with water. These findings demonstrate the potential for development of noninvasive, physical-based treatment methods of deep-tissue tumors.

Efficacy of Beauveria bassiana (Bals.) Vuill. Isolates on Dried Fruit Moth (Plodia interpunctella [Lepidoptera: pyralidae

The dried fruit moth, Plodia interpunctella (Hübner, 1813) (Lepidoptera: Pyralidae) is one of the most important pests of both dried fruits and stored grains and products. One of the alternative control methods to chemicals in the control against this pest is the use of biological control methods. Entomopathogenic fungi (EPF) stand out because they do not have any negative effects on the environment, living organism and human health, other than the target pests. In this study, ET 10 and Bb 18 isolates of Beauveria bassiana (Bals.) Vuill. were applied to the 4th instar larvae of P. interpunctella under laboratory conditions and their effectiveness was determined. EPF isolates were sprayed to the larvae in plastic petri dishes at a concentration of 1x108 conidia/ml. The experiments were carried out in a randomized plots experimental design with five replicates, with five 4th instar larvae in each petri dish. After the applications, the number of live larvae was recorded by counting the 1st, 3rd, 5th and 7th days and the % mortality rate was calculated. On the fifth day of the experiment, mortality rates of 92% were recorded for the ET 10 isolate of B. bassiana and 84% for the Bb 18 isolate. In the seventh day counts, 100% mortality rates were determined for both isolates of B. bassiana. As a result, it is concluded that B. bassiana may have a potential effect in the biological control of stored product pests.

Microarchitectured strontium doped silver niobate embedded ecoflex composite films for highly efficient box-type mechanical energy harvesters

Understanding the increasing energy demands and probable utilization of mechanical energy harvesters, current research is highly focused on enhancing their performance/applicability in everyday life. Herein, we proposed a box-type hybrid nanogenerator (BT-HNG) consisting of acetone-dissolved microarchitectured strontium (Sr) doped silver niobate (ASNb)/ecoflex composite film as a highly efficient mechanical energy harvester. The simple and unique microarchitectured (MA) master mold was fabricated by immersing a plastic petri dish inside the acetone which was further utilized to obtain MA-composite films. The ASNb microparticles (MPs) with varying the Sr doping concentration were synthesized and further loaded inside the ecoflex film to enhance its dielectric properties. The MA-ASNb/ecoflex composite films were utilized as a negative triboelectric material and copper as a positive triboelectric material for the fabrication of HNG operating in a contact-separation mode. The ASNb filler concentration inside the ecoflex film was optimized in the aspect of Sr doping and filler concentrations to obtain the highest electricity from respective HNG. The highly efficient and stable electrical output produced by the HNG was further utilized to power various small-scale electronics. The BT-HNG producing unique direct current electrical output was developed by integrating five similar HNGs in it. The enhancement in the electrical output with successive addition of each HNG was thoroughly investigated. The proposed BT-HNG was successfully demonstrated as a real-time sensor that can be utilized to turn on the lamps situated at stairs, corridors, etc. in human presence. The enclosed BT-HNG along with a heavy weighing block was demonstrated to harvest vibrational/linear movements into electricity.

Human anterior cruciate ligament-derived mesenchymal stem cells for regenerative medicine applications

Background: The anterior cruciate ligament (ACL) has poor healing capabilities and is the most commonly injured knee ligament. Although ACL repair is being highly studied, the current treatment involves reconstructive surgery utilizing autografts or allografts, which have limitations. The use of Mesenchymal Stem Cells (MSCs) as a possible therapeutic option has grown. ACL-derived MSCs are likely to be the best source because studies have shown that target tissue derived stem cells will better differentiate into the target tissue than the stem cells derived from non-target ones. However, the existing literature discusses only the isolation of a mixed population of MSCs. Here we present the isolation, differentiation and characterization of human ACL-derived MSCs according to the International Society for Cellular Therapy (ISCT) criteria.The ACL tissue was enzymatically digested. Separation of MSCs from the crude mixture of cells was then performed by fluorescence activated cell sorting (FACS) analysis. The isolated population were passaged in specific induction medium to differentiate them into adipocyte, osteocytes and chondrocytes. The cells were then further characterized with respect to their growth curve, population doubling time, colony forming ability, anchorage independent growth, and cell surface markers. The cells were finally examined for their tumorigenic potential by cell cycle analysis.Immunoprofiling via FACSs showed an average isolation rate for cells carrying MSCs markers of 5.5%. Cells exhibited spindle-shaped morphology, and immunocytochemistry confirmed the expression of appropriate cell surface markers. The growth curve showed distinct lag and log phase. Over agar assay demonstrated no anchorage independent growth, but clonogenic potential was observed post-culture on plastic Petri dishes. The cells showed a population doubling time of about 1.5 days. Oil Red O, Alizarin Red S, and Alcian Blue staining confirmed adipogenic, osteogenic and chondrogenic differentiation, respectively. Cell cycle analysis displayed more ACL-derived MSCs in G/G phase compared to BMSCs, showing that the isolates were non-tumorigenic. The presence of MSCs within the human ACL was confirmed via ISCT criteria, paving the way for their potential use for future ACL reconstructions. Although BMSCs have been the choice for regenerative purposes, making use of MSCs derived from ACL ligament will cut down the burden of trauma one has to undergo to obtain the Bone Marrow. Moreover, it is more convenient to harvest MSCs from otherwise discarded ACL. Finally, MSCs derived from the target tissue are believed to better differentiate to the ligament tissue than the bone derived MSCs.

Disinfection of Surfaces Contaminated with SARS-CoV-2 Coronavirus by UV Radiation of Low-Pressure Mercury-Vapour Lamp

The aim of the work was to determine the effective ultraviolet (UV) doses required for the disinfection of surfaces contaminated with the SARS-CoV-2 coronavirus using a low-pressure mercury lamp. Materials and methods. To carry out prompt disinfection of surfaces, a specially designed source of UV radiation with a power of 7.5 W at a wavelength of 254 nm in the form of a portable flashlight was employed, which has a high efficiency of UV radiation output and the possibility of long-term autonomous operation from a compact battery. In the studies, a suspension culture of the SARS-CoV-2 coronavirus with biological activity of 5.3∙106 PFU/ml was used. The objects of testing were plastic Petri dishes (disposable) and office paper (grade C, density 80 g/m2 ). Results and discussion. Doses of UV radiation that provide disinfection of surfaces contaminated with the COVID-19 pathogen with an efficiency of 99.0 % (paper) to 99.95 % (plastic) have been determined. The results obtained make it possible to recommend a portable UV irradiator for use in the practice of preventive measures to combat the spread of the disease caused by the SARS-CoV-2 coronavirus.

Evaluation of microbiological efficiency of use of pulsed ultraviolet devices in medical organization

Objective. To study bactericidal effect of continuous spectrum ultraviolet radiation on hospital flora and evaluate microbiological efficiency of using portable pulsed ultraviolet unit for disinfection of air and open surfaces in a medical organization. During the study, it was found that the selected research methods probably did not allow to achieve higher values of disinfection efficiency in shorter processing times.Materials and methods. The strains of microorganisms that were used for the study were taken from various loci from patients of the department of anesthesiology and intensive care for children with cardiac pathology on the first day of their transfer from various medical organizations, as well as museum strains from the collection of microorganisms of the laboratory. Single-use plastic Petri dishes with nutrient media in the laboratory were artificially contaminated with test strains. Air samples were taken during the work shift by aspiration using a Krotov’s apparatus. Wipes were taken with a sterile cotton swab dipped in nutrient medium.Results. No colonies of multiresistant K. pneumoniae, S. aureus, E. coli were detected in the samples as a result of exposure to a pulsed ultraviolet radiation source in a mode № 1; the efficiency of the action was 99.9–100%. With the regimen № 2 the efficacy was 83.33–99.9%. Assessment of microbiological efficiency of the disinfected open surfaces and air in a small operating room and a dressing room showed that the level of air contamination did not exceed the permissible level.Conclusions. It has been experimentally proved that pulsed UV radiation of broadband spectrum has high bactericidal activity against microorganisms of hospital environments.

Designing a Bioreactor to Improve Data Acquisition and Model Throughput of Engineered Cardiac Tissues.

Heart failure remains the leading cause of death worldwide, creating a pressing need for better preclinical models of the human heart. Tissue engineering is crucial for basic science cardiac research; in vitro human cell culture eliminates the interspecies differences of animal models, while a more tissue-like 3D environment (e.g., with extracellular matrix and heterocellular coupling) simulates in vivo conditions to a greater extent than traditional two-dimensional culture on plastic Petri dishes. However, each model system requires specialized equipment, for example, custom-designed bioreactors and functional assessment devices. Additionally, these protocols are often complicated, labor-intensive, and plagued by the failure of the small, delicate tissues. This paper describes a process for generating a robust human engineered cardiac tissue (hECT) model system using induced pluripotent stem-cell-derived cardiomyocytes for the longitudinal measurement of tissue function. Six hECTs with linear strip geometry are cultured in parallel, with each hECTsuspended from a pair of force-sensing polydimethylsiloxane (PDMS) posts attached to PDMS racks. Each post is capped with a black PDMS stable post tracker (SPoT), a new feature that improves the ease of use, throughput, tissue retention, and data quality. The shape allows for the reliable optical tracking of post deflections, yielding improved twitch force tracings with absolute active and passive tension. The cap geometry eliminates tissue failure due to hECTs slipping off the posts, and as they involve a second step after PDMS rack fabrication, the SPoTs can be added to existing PDMS post-based designs without major changes to the bioreactor fabrication process. The system is used to demonstrate the importance of measuring hECT function at physiological temperatures and shows stable tissue function during data acquisition. In summary, we describe a state-of-the-art model system that reproduces key physiological conditions to advance the biofidelity, efficiency, and rigor of engineered cardiac tissues for in vitro applications.

Efficacy of Nets Coated with Different Concentrations of Alpha-Cypermethrin against Two Major Pests of Stored Tobacco

In the present study, we examined the insecticidal effect of Carifend® (BASF AG, Ludwigshafen, Germany; 163.2 mg m−2), an alpha-cypermethrin-coated polyester net, as well as Carifend-like nets containing different rates of alpha-cypermethrin, specifically 10, 30, 80, and 325 mg m−2, against two major stored tobacco insect pests, i.e., Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae) and Ephestia elutella (Hübner) (Lepidoptera: Pyralidae). The nets were glued at the bottom of plastic Petri dishes, and adults of L. serricorne and E. elutella were exposed to the nets for different exposure times (e.g., 1, 5, 15, 30, 60, 90, and 120 min, as well as 12 and 24 h). After each exposure interval, insect mortality was recorded, whereas after the final evaluation, alive individuals were transferred to untreated dishes, and delayed mortality was recorded after an additional period of 1, 3, 5, and 7 d. Based on our results, efficient control of both insect species was achieved with all nets, even the one containing a lower concentration of alpha-cypermethrin (10 mg m−2). High mortality rates were recorded for all treatments, indicating that even short exposure of adults of both tested species to the alpha-cypermethrin-coated nets tested can lead to mortality. For instance, at 30 mg m−2, mortality of E. elutella reached 40% 1 d after exposure for 30 min. Moreover, at the highest concentration (325 mg m−2), mortality reached 70% and 99% 7 d post exposure for 24 h of L. serricorne and E. elutella, respectively. Based on these data, Carifend®, as well as the rest of the Carifend-like nets tested, can be used as an alternative insecticide method for the control of two major stored tobacco insect species, i.e., L. serricorne and E. elutella. Insecticide treated nets can be used in areas in which fumigants and contact insecticides are not accessible.

Bacterial filtration efficiency of medical face masks – Evaluation of the use of disposable plastic petri dishes in Andersen impactor

Bacterial filtration efficiency is the main characteristic of medical face masks effectivity and quality. The testing method is given by European and US, respectively, standard. The method is based on the analysis of biological aerosol with the bacterium Staphylococcus aureus in Andersen cascade impactor. The Andersen impactor contains six stages simulating the different parts of the respiratory tract, from the upper part with the larger droplets to the lungs with the small aerosol particles of the submicron size. The particles are separated depending on the size and sediment on agar medium in Petri dishes filled in the impactor. The use of the glass Petri dishes is recommended for the Andersen impactor, but the most of laboratories prefer the disposable plastic dishes, actually. The evaluation of the use of plastic dishes in Andersen impactor for the determination of the bacterial filtration efficiency of the medical face masks is the aim of this study.

The effect of different gelling agents as part of culture medium on the rate of cucumber (<i>Cucumis sativus</i> L.) unpollinated ovules gynogenic development

Relevance. The induction of gynogenic development of the culture of unpollinated ovules of Cucumis sativus L., as a part of solid nutrient media agar-agar or Phytagel™ are used as a gelling agent. The gelling agent determines the mobilization of substances in the composition of the nutrient medium and has various effects on the explants, which affects the quality of the resulting regenerates. However, there are no scientific works that explaines the effect of these gelling agents on the development of ovules and compare them with each other for C. sativus L. The aim: investigate the effect of various gelling agent in the nutrient medium on the induction of gynogenesis and the development of cucumber unpollinated ovules.Materials and methods. There are two promising collection specimens of cucumber №58 and №831 of the laboratory of cucurbits crop breeding and seed production of FSBSI FSVC were included into research. IMC nutrient medium (Induction Medium for Cucurbitaceae) with 30 g/l sucrose, 200 mg/l ampicillin, 0.2 mg/l thidiazuron (TDZ) was used for the induction of gynogenesis; agar-agar at a concentration of 7 g/l or Phytagel™ at a concentration of 3.5 g/l was used as a gel-forming agents. Ovules were isolated from ovaries in the phase of half-opened flower (FL-1) and fully opened flower (FL). Cultivation was carried out in plastic Petri dishes with a diameter of 60 mm with an air gap of 28.8 cm3 – "KS No. 1", and glass culture jars with an air gap of 140 cm3 – "KS No. 2".Results. On containing Phytagel™ or agar-agar nutrient medium, the area of ovules during 30 days of cultivation increases irregularly. Coefficients of ovule enlargement between gelling agents differed from 1.7 to 2.6 times depending on the cultivation time. The average growth rate of ovules on media with Phytagel™ was 0.08 mm2/day, while on media with agar-agar it was 0.02 mm2/day. Gelling agents type and cucumber phenotype are significant factors affecting the increase in area of entered into unpollinated cucumber ovules culture. Herewith the share of the gelling agent effect was 55.01%, and the share of genotype effect was 14.53%. The effect of flower development stage or culture vessel type has not found for both of genotypes. In the study, it was possible to achieve the induction of gynogenesis in 67% of the unpollinated ovules genotype №831 on nutrient medium with agar-agar.Conclusion. Ovules development were faster on a nutrient medium using Phytagel™ as a gelling agent than on agaragar. At the same time, the percentage of induced ovules was significally higher on nutrient medium with agar-agar for both phenotypes. Gelling agents type and cucumber phenotype were found as significant factors of the induction and the development of unpollinated ovules.

Investigation of Sterilization Effect for Overlapping Pieces in Non-Thermal Sterilization Method of Packaged Fresh Foods Using Pulsed Barrier Discharge

It is important to secure food safety. If a packaged food can be sterilized, food poisoning can be reduced considerably because the packaged food in a plastic container is useful to prevent attaching microorganisms. However, a fresh food, e.g., a salad or sashimi, cannot be sterilized by thermal sterilization. Therefore, we are studying sterilization methods for packaged fresh foods, such as packed salads. In this study, we have investigated the applicable probability of the sterilization method using cold plasma applied to the packaged fresh food. Especially, we have investigated the probability of the sterilization of microorganisms living in a small hollow between the overlapped fresh foods. A plastic petri dish with a lid was used for simulating the plastic container. The cold plasma was applied into the petri dish by a barrier discharge generated by a pulsed voltage. E. coli was used for a target of sterilization. The E. coli was set on a culture agar medium instead of the salad. The experimental results showed that the sterilization method combining the plastic film and cold plasma of the barrier discharge generated by the pulsed voltage is applicable to sterilize microorganisms living in the hollow between the overlapped fresh foods for the packaged fresh food.

VIRULENCE OF ENTOMOPATHOGENIC NEMATODES TO THREE SOFT SCALE INSECT SPECIES

Virulence of commercial strains of entomopathogenic nematode (EPN) Steinernema carpocapsae (Weiser), Steinernema feltiae Filipjev and Heterorhabditis bacteriophora Poinar (Rhabditida: Steinernematidae, Heterorhabditidae), were tested on young females of Pulvinaria hydrangeae Steinweden, Partenolecanium corni (Bouché) and Coccus pseudomagnoliarum (Kuwana) (Hemiptera, Coccidae) and a native strain of H. bacteriophora was tested on citricola scale, C. pseudomagnoliarum. The laboratory tests were carried out in small plastic Petri dishes with infective juveniles (IJ) applied on filter paper covering the bottom. Results showed that all EPN tested were virulent to all three soft scale insect species. Recorded mortality of insects at the highest concentration of approximately 50 IJ per cm2 exceeded 64% in all combinations of nematode and scale species tested. Within the same nematode concentration, scales’ mortality of 90% and above was recorded for P. corni with all nematode species, P. hydrangeae with S. carpocapsae (Nemastar) and C. pseudomagnoliarum with native H. bacteriophora strain. All scale species were good hosts for all nematode species. This is the first report of EPNs to parasitize soft scale insects and one of the few among Coccoidea. The level of parasitism recorded is promising for potential use in management of scale insects.

Additive manufacturing-based recycling of laboratory waste into energy harvesting device for self-powered applications

The laboratory waste produced in several parts of the world has scaled up the pollution and adverse effect on human health in the present era. The “3 R” (reduce, reuse, and recycle) scheme is adopted by many communities for efficiently recovering waste products and utilizing them for the production of energy. In the present work, the laboratory waste is collected and directly utilized for fabricating a laboratory waste-based triboelectric nanogenerator (LW-TENG) operating in vertical contact-separation mode. The substrate, electrode, and triboelectric layer are randomly selected from lab waste. The waste plastic petri dishes were extruded into thin filament wires for 3D printing of the substrate for the LW-TENG. The effective electrical output is generated by LW-TENG having a triboelectric layer plastic-glass delivering voltage of 185 V, current of 1.25 μA, and power density of 8.1 μW/cm2 across the load resistance of 500 MΩ. The positive and negative triboelectric layers are altered and the electrical output is systematically investigated. Additionally, the LW-TENG device is attached to various locations of the laboratory to demonstrate the energy harvesting from the mechanical motions. It is also utilized for demonstrating real-time applications that could be beneficial as a self-powered human tracking device (HSD) that tracks the location of the human during an emergency and self-powered exercise counter.

Residual efficacy of an insecticide-coated net for the control of stored product beetles

In the present study, the residual efficacy of an alpha-cypermethrin-coated net (Carifend®, BASF AG, Ludwigshafen, Germany) was evaluated in laboratory studies against four species of stored product insects. The insecticide-treated net was fitted into the bottom of plastic petri dishes, whereas two other sets of dishes (without net, with net without insecticide) served as controls. The insects used in the bioassays were Sitophilus oryzae, Tribolium confusum, Oryzaephilus surinamensis and Prostephanus truncatus. Adults of these species were exposed every 30 d for a total of 90 consecutive days in total. Based on the results, the insecticidal effect of the net remained at high levels during the entire experimental period, indicating its high residual effect. Among the species tested, T. confusum was the least susceptible. Carifend® can be a valuable tool for the protection of stored products against storage insects, and its use can be further examined towards this direction.

Obstructs-equipped apparatus reduces cannibalism and improves larval survival of the Coccinellid, Harmonia axyridis (Coleoptera: Coccinellidae)

BackgroundHarmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is an important biocontrol agent in native region of Asia, while its high propensity for cannibalism causes great obstacles in mass production. Provisioning obstructs in rearing containers could decrease the cannibalism of ladybird beetles. In this study, three different patterns of obstructs (Con-A, Con-B, and Con-C) were designed and equipped in plastic Petri dishes (95.38 cm3) as rearing units, and their efficiency for H. axyridis larval survival was tested. The potential of the high-density rearing was then evaluated using the optimal units with 16, 24, or 32 larvae per unit (named 16-L, 24-L, or 32-L, respectively).ResultsLarval survivals in obstructs-equipped units were generally higher than those in control, and significantly increased with the Con-C units (39.8% versus 74.2% at adult stage). With the Con-C units, the survivals were significantly higher at 16-L density (82.5%) than those at 24-L density (62.5%), but both were non-significantly different from those at 32-L density (70.0%). The weights of newly emerged adults (fit with the expected sex ratio of 1:1) at the higher densities were lower than those at 16-L density.ConclusionsThe results demonstrate that H. axyridis can be reared at a higher density (≈ 0.336 larvae/cm3) in a constrained unit and highlight the effects of obstructs in reducing cannibalism and improving insect survivals.

Bisphenol–based cyanide sensing: Selectivity, reversibility, facile synthesis, bilateral “OFF-ON” fluorescence, C2ν structural and conformational analysis

A structurally characterized novel dual–pocketed tetra–conjugated bisphenol–based chromophore (fluorescence = 652 nm) was synthesized in gram scale in ~90% yield from its tetraaldehyde. Highly selective, naked-eye detection of CN− (DMSO/H2O) was confirmed by interferent testing. A detection limit of 0.38 µM, within the permissible limit of CN− concentration in drinking water was achieved as mandated by WHO. The “reversibility” study shows potential applicability and reusability of Sen. Moreover, cost-effective and on-site interfaces, application tools such as fabricated cotton swabs, plastic Petri dishes, and filter papers further demonstrated the specific selectivity of Sen for the toxic CN−. In addition, an easily available and handy smartphone-assisted “Color Picker” app was utilized to help estimate the concentration of CN− ion present. A dual phenol deprotonation mechanism is active and supported by 1H NMR spectroscopic data and DFT calculation results.

Electrostatic Method to Remove Particulate Organic Matter from Soil.

Estimations of soil organic carbon are dependent on soil processing methods including removal of undecomposed plant material. Inadequate separation of roots and plant material from soil can result in highly variable carbon measurements. Methods to remove the plant material are often limited to the largest, most visible plant materials. In this manuscript we describe how electrostatic attraction can be used to remove plant material from a soil sample. An electrostatically charged surface passed close to dry soil naturally attracts both undecomposed and partially decomposed plant particles, along with a small quantity of mineral and aggregated soil. The soil sample is spread in a thin layer on a flat surface or a soil sieve. A plastic or glass Petri dish is electrostatically charged by rubbing with polystyrene foam or nylon or cotton cloth. The charged dish is passed repeatedly over the soil. The dish is then brushed clean and recharged. Re-spreading the soil and repeating the procedure eventually results in a diminishing yield of particulates. The process removes about 1 to 5% of the soil sample, and about 2 to 3 times that proportion in organic carbon. Like other particulate removal methods, the endpoint is arbitrary and not all free particulates are removed. The process takes approximately 5 min and does not require a chemical process as do density flotation methods. Electrostatic attraction consistently removes material with higher than average C concentration and C:N ratio, and much of the material can be visually identified as plant or faunal material under a microscope.