Vegetable Samples Research Articles

Deep-learning assisted detection and quantification of (oo)cysts of Giardia and Cryptosporidium on smartphone microscopy images

The consumption of microbial-contaminated food and water is responsible for the deaths of millions of people annually. Smartphone-based microscopy systems are portable, low-cost, and more accessible alternatives for the detection of Giardia and Cryptosporidium than traditional brightfield microscopes. However, the images from smartphone microscopes are noisier and require manual cyst identification by trained technicians, usually unavailable in resource-limited settings. Automatic detection of (oo)cysts using deep-learning-based object detection could offer a solution for this limitation. We evaluate the performance of four state-of-the-art object detectors to detect (oo)cysts of Giardia and Cryptosporidium on a custom dataset that includes both smartphone and brightfield microscopic images from vegetable samples. Faster RCNN, RetinaNet, You Only Look Once (YOLOv8s), and Deformable Detection Transformer (Deformable DETR) deep-learning models were employed to explore their efficacy and limitations. Our results show that while the deep-learning models perform better with the brightfield microscopy image dataset than the smartphone microscopy image dataset, the smartphone microscopy predictions are still comparable to the prediction performance of non-experts. Also, we publicly release brightfield and smartphone microscopy datasets with the benchmark results for the detection of Giardia and Cryptosporidium, independently captured on reference (or standard lab setting) and vegetable samples. Our code and dataset are available at <a href='https://github.com/naamiinepal/smartphone_microscopy'>https://github.com/naamiinepal/smartphone_microscopy</a> and <a href='https://doi.org/10.5281/zenodo.7813183'>https://doi.org/10.5281/zenodo.7813183</a>, respectively

Antibiotic Resistance Profiles of Escherichia coli and Salmonella spp. Isolated From Dairy Farms and Surroundings in a Rural Area of Western Anatolia, Turkey.

Background Antibiotic resistance is a significant public health issue worldwide. Antibiotic-resistant zoonotic bacteria such as Escherichia coli (E. coli), Campylobacter, Salmonella, Listeria, Coxiella, and Mycobacterium can be particularly isolated from biofertilizers. Epidemiological studies have shown that cases of foodborne infections and intoxications are significantly related to animal-derived foods. The presence of these species in aquatic environments indicates areas or organisms contaminated with animal or human feces. Especially, the presence of E. coli in aquatic environments has become a serious problem worldwide. Pathogenic strains of E. coli cause waterborne and foodborne diseases. Materials and methods This study included a total of 290 samples collected from five different dairy farms between April and September 2023 which comprised 20 samples of cow manure, 20 samples of milk, three samples of dairy workers' hand washing water, five samples ofsoil, five samples of water, and five samples of vegetables. The samples taken from the farms were homogenized with 0.1% peptone water at a ratio of 1/10. They were then cultured on xylose lysine deoxycholate (XLD), eosin methylene blue agar (EMB), and blood agar media, and gram-negative colonies were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and the VITEK2 automated system (BioMerieux Inc., Durham, NC). Amplification of the isolated DNA extracts was performed with A.B.T.™ 2X HS-PCR MasterMix (A.B.T Laboratory Industry, Arnavutköy, Turkey) in the SimpliAmp™ thermal cycler (Thermo Fischer Scientific Inc., Waltham, MA) and visualized by agarose gel electrophoresis. Results Among the 52E. coli strains isolated in our study, the highest antibiotic sensitivity rate was observed in meropenem, while the lowest sensitivity rates were determined in cefazolin and cefuroxime. While two of the Salmonella spp. (n = 2) isolates were found to be resistant to tetracycline, and one was found to be resistant to penicillin and ampicillin. No resistance to trimethoprim/sulfamethoxazole was detected in either isolate. Extended-spectrum beta-lactamases (ESBLs) were detected in only four (7.7%) E. coli strains. While tetA, tetB, and TEM genes were seen in almost all E. coli strains, they were not found in Salmonella spp. Conclusion In conclusion, our study revealed the presence of antimicrobial resistance genes in E. coli and Salmonella spp. isolates collected from various farms and environmental samples, which render the antimicrobials used for disease treatment ineffective. Consequently, research should be undertaken to prevent the development of new resistance genes in our country, as creating new medications and treatment strategies for these diseases is costly and time-intensive.

Monoclonal antibody based colloidal gold immunochromatographic assay for the visual and rapid screening of profenofos

Profenofos (PFF) is a commonly used organophosphorus insecticide that requires strict monitoring due to its potential environmental, ecological, and human health risks originating from residues in soil and water systems, as well as accumulation in crops. In this study, a novel monoclonal antibody (mAb) specific to PFF was prepared for the first time and the recognition mechanism was investigated through molecular simulation. Subsequently, a mAb-based colloidal gold immunochromatographic assay (GICA) was developed for the rapid screening of PFF in fruit and vegetable samples. The mAb exhibited an IC50 value of 12.9 ng/mL, and limit of detection (LOD) of 4.6 ng/mL, respectively in indirect competitive immunosorbent enzyme-linked immunosorbent assay (ic-ELISA). After optimization, the developed GICA exhibited a visual limit of detection (vLOD) of 20 ng/mL and a quantitative of detection (qLOD) of 5.2 ng/mL, with a linear range from 10.0 to 83.8 ng/mL. Good correlation was observed between the results of GICA and standard Gas Chromatography-Tandem Mass Spectrometry (GC-MS/MS) in matrix and recovery test. The developed GICA can be used for rapid sample detection within 15 min, which is an excellent tool for screening PFF in foods and environmental samples.

Nitrogen-Doped Carbon Dots Enhanced Hydrogen Carbonate-Hydrogen Peroxide Chemiluminescent Reaction and its Application in Ascorbic Acid Sensing.

Nitrogen-doped carbon dots (N-CDs) were prepared by self-exothermic procedure using grasshopper powder as a single precursor. The prepared N-CDs not only have excellent fluorescence properties, but also can catalyze and enhance the ultra-weak chemiluminescence of NaHCO3-H2O2. The reaction conditions of NaHCO3-H2O2-N-CDs CL were optimized. Under the optimal experimental conditions, when AA was added to the NaHCO3-H2O2-N-CDs CL system, AA had a significant inhibitory effect on the CL intensity of NaHCO3-H2O2-N-CDs. There was a good linear relationship between the calculated lg(I0/I) and the concentration of AA (C), and the calibration curve equation was lg(I0/I) = 0.03667C-0.00708 (µM). The established CL analysis method has a detection limit of 0.12 µM for AA and a linear range of 0-50 µM. The selectivity of CL method was evaluated, and the method was successfully applied to the determination of AA in vegetable and fruit samples. The spiked recoveries were between 88.9% and 118.9%, which indicated that the method was simple, rapid, and sensitive, and had great potential in the determination of AA in foods.

Grassland degradation affected vegetation carbon density but not soil carbon density

BackgroundWith the profound changes in the global climate, the issue of grassland degradation is becoming increasingly prominent. Grassland degradation poses a severe threat to the carbon cycle and carbon storage within grassland ecosystems. Additionally, it will adversely affect the sustainability of food production. The grassland ecosystem in the northwest region of Liaoning Province, China, is particularly vulnerable due to factors such as erosion from the northern Horqin Sandy Land, persistent arid climate, and issues related to overgrazing and mismanagement of grassland. The degradation issue is especially pronounced in this ecological environment. However, previous research on the carbon density of degraded grasslands in Northeast China has predominantly focused on Inner Mongolia, neglecting the impact on the grasslands in the northwest of Liaoning Province. Therefore, this experiment aims to assess the influence of grassland degradation intensity on the vegetation and soil carbon density in the northwest of Liaoning Province. The objective is to investigate the changes in grassland vegetation and soil carbon density resulting from different degrees of grassland degradation.MethodologyThis study focuses on the carbon density of grasslands at different degrees of degradation in the northwest of Liaoning Province, exploring the variations in vegetation and soil carbon density under different levels of degradation. This experiment employed field sampling techniques to establish 100 × 100 m plots in grasslands exhibiting varying degrees of degradation. Six replications of 100 × 100 m plots per degradation intensity were sampled. Vegetation and soil samples were collected for analysis of carbon density.ResultsThe results indicate that in the context of grassland degradation, there is a significant reduction in vegetation carbon density. Furthermore, it was found that root carbon density is the primary contributor to vegetation carbon density. In comparison to mildly degraded grasslands, moderately and severely degraded grasslands experience a reduction in vegetation carbon density by 25.6% and 52.6%, respectively. However, with regard to the impact of grassland degradation on soil carbon density, it was observed that while grassland degradation leads to a slight decrease in soil carbon density, there is no significant change in soil carbon density in the short term under the influence of grassland degradation.ConclusionsTherefore, grassland degradation has exerted a negative impact on aboveground vegetation carbon density, reducing the carbon storage of above-ground vegetation in grasslands. However, there was no significant effect on grassland soil carbon density.

Profiles of volatile sulfur compounds in various vegetables consumed in Korea using HS-SPME-GC/MS technique.

Volatile sulfur compounds (VSCs) are not only important for their therapeutic potential but also significantly influence the flavor profiles of agricultural products. VSCs exhibit various chemical structures due to their stability and volatility, and they may form or be altered as a result of enzymatic and chemical reactions during storage and cooking. This study has focused on profiles of VSCs in 58 different vegetable samples by using HS-SPME-GC/MS technique and chemometric analyses. The validation was carried out using cabbage juice as a vegetable matrix for VSCs analysis, showing satisfactory repeatability (RSD 8.07% ~ 9.45%), reproducibility (RSD 4.22% ~ 7.71%), accuracy and specificity. The established method was utilized on various vegetables, revealing that 21 VSCs such as sulfides, disulfides, trisulfides, isothiocyanates, sulfhydryls, and thiophenes were successfully identified and quantified. These compounds were found in a range of vegetables including Allium species, Cruciferae, Capsicum species, green leafy vegetables, and mushrooms. In particular, isocyanate and allyl groups were abundant in Cruciferae and Allium vegetables, respectively. Cooking conditions were shown to reduce the levels of certain sulfur compounds such as dimethyl sulfide and dimethyl trisulfide in vegetables like broccoli and cabbage, suggesting that heat treatment can lead to the volatilization and reduction of these compounds. The present study provides reliable insights into the compositions of VSCs in various vegetables and examines the changes induced by different cooking methods.

Occurrence of bisphenol analogues and their conjugated metabolites in foodstuff

Bisphenol analogues (BPs) are prevalent in diverse foodstuff samples worldwide. However, the occurrence of conjugated bisphenol A (BPA) and bisphenol S (BPS) metabolites in foodstuff remains poorly understood. This study analyzed eight BPs, and four conjugated BPA and BPS metabolites, in three animal-derived foodstuff and five plant-derived foodstuff samples from China. Results showed that fish foodstuff (9.7 ng/g ww) contained the highest mean concentration of BPA, followed by rice (5.1 ng/g ww) and beans foodstuff (3.6 ng/g ww). BPA-sulfate had higher mean concentrations than BPA-glucuronide in different foodstuff categories, except that in eggs foodstuff (p < 0.05). Compared with other foodstuff items, fish (3.4 ng/g ww) and vegetable (1.6 ng/g ww) foodstuff samples exhibited comparatively higher mean concentrations of BPS. Mean concentrations of BPS-sulfate were consistently higher than BPS-glucuronide in vegetables, meats, and fish foodstuff (p < 0.05). BPA contributed the major total dietary intake (DI) of BPs, with the mean DI of 435 ng/kg bw/day for women and 374 ng/kg bw/day for men, respectively. To our knowledge, this study is the first to investigate the occurrence of conjugated BPA and BPS metabolites in foodstuff, which enhances our comprehension of the origins of these conjugated metabolites in the human body.

Near-infrared fluorescent probe for ultrasensitive detection of organophosphorus pesticides and visualization of their interaction with butyrylcholinesterase in living cells

The toxicity of organophosphorus pesticides (OPs) can catastrophically cause liver cell damage and inhibit the catalytic activity of cholinesterase. We designed and synthesized a near-infrared fluorescent probe HP-LZB with large Stokes shift which can specifically identify and detect butyrylcholinesterase (BChE) and visually explore the interaction between OPs and endogenous BChE in living cells. Fluorescence was turned on when HP-LZB was hydrolyzed into HP-LZ in the presence of BChE, and OPs could inhibit BChE's activity resulting in a decrease of fluorescence. Six OPs including three oxon pesticides (paraoxon, chlorpyrifos oxon and diazoxon) and their corresponding thion pesticides (parathion, chlorpyrifos and diazinon) were investigated. Both in vitro and cell experiments indicated that only oxon pesticides could inhibit BChE's activity. The limits of detection (LODs) of paraoxon, chlorpyrifos oxon and diazoxon were as low as 0.295, 0.007 and 0.011 ng mL−1 respectively and the recovery of OPs residue in vegetable samples was satisfactory. Thion pesticides themselves could hardly inhibit the activity of BChE and are only toxic when they are converted to their corresponding oxon form in the metabolic process. However, in this work, thion pesticides were found not be oxidized into their oxon forms in living HepG2 cells due to the lack of cytochrome P450 in hepatoma HepG2 cell lines. Therefore, this probe has great application potential in effectively monitoring OPs in real plant samples and visually exploring the interaction between OPs and BChE in living cells.

Accumulation of heavy metals and arsenic in plants in the vicinity of the Chadan coal deposit (Republic of Tuva)

The content of copper, zinc, lead, cadmium and cobalt in plant samples from the vicinity of the Severny dump of the Chadansky coal mine in the Republic of Tuva was studied. Heavy metals in plant samples were determined by the Quantum-2mt atomic absorption spectrophotometer. Due to the extra-arid conditions, the studied area belongs to the zone of risky agriculture and there is developed cattle breeding. It was revealed that vegetation typical for steppe communities is developed on the territory of the Chadan coal deposit, represented by wormwood-cereal, grass-grass-wormwood, grass-wormwood-kovyl, wormwood-grass-grass steppes. In the dumps, deposits of different ages with small-scale, wormwood-cereal communities with typically steppe species are developed. For lead, cadmium and cobalt, the concentrations in vegetation samples from the CER and SWZ sites adjacent to the dump turned out to be close to their background values. The Cu content in the vegetation of the dump sites exceeds the natural content by 2–2,2 times, Zn – 2–2,7 times, Pb – 1,5 times. However, a comparison of the content of Cu, Cd, Zn, Pb, Co in vegetation from 2 sites of the Severny dump and the background territory with MDU for plant feeds showed that their concentrations in the studied samples are much lower than the maximum permissible level.

A Vértesalja homoki cseres-tölgyesei (Fraxino orno-Quercetum cerridis Kevey 2008)

Here we evaluate the phytosociological characteristics of the turkey oak forests on sand (Fraxino orno-Quercetum cerridis) found at the northern foothills of the Vértes Hills, Hungary. Using the traditional Braun-Blanquet method, 20 vegetation samples were collected and compared with turkey oak forests growing in similar ecological situations in other parts of the country. The traditional and multivariate analyses showed that our samples were quite different from the compared forests, and only the forests in the Bakonyalja and the Pilis Mts showed some similarity with the compared forests. Our samples had the lowest proportion of Quercetea pubescentis-petraeae species among the compared forests, and the highest proportion of specialists (Corydalis pumila, Daphne laureola, Doronicum hungaricum, Lychnis coronaria, Physocaulis nodosus, Primula veris, Scutellaria columnae, Sorbus domestica and Veratrum nigrum). The samples were well separated from the compared forests and formed a distinct group.

Parasitic Contamination of Raw Vegetables Consumed in Benghazi City-Libya

Twelve different types of fresh vegetables were randomly selected from the wholesale and retail markets in Benghazi city and examined for the presence of parasites using standard parasitological techniques. Out of 5712 vegetable samples examined 1416 (24.8%) were found contaminated with one or more parasitic stages (trophozoite-cyst-oocystegg-larva). The parasites detected include Entamoeba histolytica/E. dispar (67.6%), Entamoeba coli (4.9%), coccidia oocysts (9.9%), Toxocara (50%), Ascaris lumbricoides (9.4%), Taenia/Echinococcus (18.6%) and Hymenolepis nana (13%). The incidence of the parasites was found to be 37.2% on rockets, 35.5% on coriander, 30.7% on parsley, 29% on Swiss chard, 28.8% on the green onion, 28% on carrots, 22.9% on radish and dill, 19.5% on lettuce, 18.3% on cucumber, 14.1% on tomato and 12.4% on cabbage. The result of this study stressed the importance of raw vegetables consumed in Benghazi in the transmission of intestinal parasites and it is important to implement hygienic principles from production to consumption of these vegetables.

Highly sensitive analysis of fatty aldehydes in vegetable oils using a novel coumarin-based fluorescent probe by HPLC for quality control

A novel fluorescent probe, 3-(4-((hydroxylamino)methyl)-1H-pyrazol-1-yl)-7-methoxyl coumarin (HAPMC), has been designed and synthesized. The compound exhibits exceptional fluorescence properties due to a coumarin-pyrazolyl fluorophore. Moreover, it incorporates an N-hydroxylamine functional group capable of reacting with aldehydes to yield nitrone derivatives under mild conditions. This unique combination renders it an ideal derivatization reagent for aldehyde analysis. A standard method was established for the quantitative analysis of eight fatty aldehydes by utilizing high-performance liquid chromatography with fluorescence detection (HPLC-FLD) and a pre-column derivatization process, which has low detection limits (0.3–1.2 nM), satisfactory reproducibility (intraday and interday relative standard deviations in the range of 1.29 %-2.92 % and 1.73 %-3.45 %), and an extensive linear range (25–5000 nM) with excellent linearity (R2 ≥ 0.9989). The spiked recoveries of the fatty aldehydes range from 89.6 % to 106.0 %. The greenness and sustainability of our approach are reinforced by evaluations conducted with the AGREE and RGB 12 algorithms. The established method was successfully applied to the qualitative and quantitative detection of fatty aldehydes in nine real vegetable oil samples, including peanut, canola, rice, soybean, olive, rapeseed, corn, sunflower, and blended oils. The fatty aldehydes are known to have adverse effects on human health due to their carcinogenic and mutagenic properties. The findings revealed that hexanal and nonanal were the most prevalent saturated fatty aldehydes, with a notable increase in the total aldehyde concentration observed as the temperature and duration of heating increased. Compared to alternative analytical techniques, this pre-column derivatization method utilizing HAPMC displayed simplicity, reliability, and sensitivity. The results demonstrate the potential for broad application of this approach in various important research domains, including food quality control, environmental monitoring, and medical research.

ZIF-8-wrapped AgNPs modified with β-cyclodextrin for sensitive detection of thiacloprid and imidacloprid by SERS technology

The high efficient surface-enhanced Raman scatterring (SERS) methods to detect thiacloprid and imidacloprid were established using ZIF-8-wrapped Ag nanoparticles (AgNPs) modified with β-cyclodextrin (β-CD). The substrate of ZIF-8/β-CD@AgNPs was characterized by ultraviolet visible spectra (UV–vis), thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The interaction between the substrate and thiacloprid/imidacloprid was also explored. The optimum measurement conditions were obtained by response surface model based on single-factor experiments. Enhancement factors (EFs) of thiacloprid and imidacloprid were respectively 2.29 × 106 and 2.60 × 106. A good linearity between the scattering intensity and the concentration of thiacloprid/imidacloprid within 3–1000 nmol L−1/6–400 nmol L−1 was established. The interference experiments indicated that the methods had good selectivity. The SERS methods were successfully applied to detect thiacloprid and imidacloprid in several vegetables samples. The recoveries ranged from 95.5 % to 105 % (n = 5). The detection limits (LODs) (S/N = 3) for thiacloprid and imidacloprid were 1.50 and 0.83 nmol L−1, respectively.

Preparation of W-N-C single atom catalyst and Cu3(HHTP)2 metal-organic framework dual-decorated graphene nanoplatelet flexible electrode arrays for the rapid detection of carbendazim in vegetables

It is highly desirable to develop a low-cost and rapid detection method for trace levels of carbendazim fungicide residues, which would be beneficial for improving human health and mitigating environmental issues. Herein, isolated single tungsten atoms were implanted onto well-organized metal–organic framework (MOF)-derived N-doped carbons to form W-N-C single-site heterojunctions with ultrahigh electrocatalytic activity. The coupling of W-N-C with Cu3(HHTP)2, an electronically conductive MOF with a large surface area and porous structure, exhibited enhanced electrocatalytic performance for the oxidation of carbendazim (CBZ) when they were used for decorating graphene nanoplatelet flexible electrode arrays fabricated via template-assisted scalable filtration. A wide linear range (3.0 nM–50 μM) with an ultra-low detection limit of 0.97 nM and fast response was achieved for CBZ analysis. Moreover, the sensing platform has been utilised to monitor CBZ levels in vegetable samples with satisfactory recovery rates of 97.2–102% and a low relative standard deviation of 1.9%.

Results of modern radiation-hygienic surveys of settlements of Bryansk Oblast of the Russian Federation bordering the Republic of Belarus. Part 3: Radionuclide content in agricultural food products

The third article in a series of publications devoted to the results of studying the current radiation situation in the territories of the Bryansk region bordering the Republic of Belarus presents results of studies of the content of radionuclides (137Cs and 90Sr) in samples of agricultural food products produced in the personal subsidiary plots of the population. The regularities of changing 137Cs and 90Sr content in samples of cow’s milk and potatoes depending on the level of radioactive contamination of the territory were studied; the present values of the quantities characterizing the distribution of the ratio of the activity concentration of radionuclides in agricultural food products to the density of radioactive contamination of the soil of the territory were deter -mined. The ratios of average values of 137Cs activity concentration in milk from stalled and grazing periods for cattle were analyzed. The results of the study show that some dairy product samples (less than 1%) do not meet the radiological safety criterion. Exceedances of the hygienic standards were not found in the studied samples of potatoes, vegetables, and meat of farm animals.

Pesticides in vegetables and fruits from Brazil and risk assessment

ABSTRACT Levels of 237 pesticides were assessed in 1063 fruit and vegetable samples from 12 São Paulo markets spanning the period May 2015 to December 2022. The QuEChERS method was employed for extraction, followed by GC-MS/MS and LC-MS/MS analysis. Findings indicated that 30% of the samples contained residues below the Maximum Residue Limits (MRLs), while 6% exceeded these. Additionally, 23% exhibited excessive residues for their respective crops and 40% had no detectable residues. Health risk evaluation focused on tomatoes, cabbage and oranges, revealing exposure within 0.002–0.9% of the Acceptable Daily Intake (ADI), indicating no chronic risks. However, pyraclostrobin in orange presented a potential acute risk for adults (112%). These results underscore the necessity for continuous monitoring of pesticide residues in fruits and vegetables to safeguard consumer health, especially considering the significant levels of consumption.

Designed fluorescence "on-off-on" probe based on cobalt, zinc, and nitrogen co-doped graphene quantum dots: A case of quinalphos sensing.

In this study, we developed a new fluorescence "on-off-on" sensor utilizing water-soluble cobalt/zinc-nitrogen co-doped graphene quantum dots (Co/Zn-N-GQDs) to recognize quinalphos pesticide in vegetable and fruit samples. Primarily, the synthesis method employed a one-pot hydrothermal approach, using betel leaves as a natural precursor and cobalt ("Co"), zinc ("Zn"), and urea ("N") as dopant sources. The Co/Zn-N-GQDs probes underwent comprehensive analytical characterization. The Co/Zn-N-GQDs were synthesized with a remarkable luminescence yield of 31.49%, exhibiting excitation at 320 nm and emission peak at 393 nm. Interestingly, the luminescence of Co/Zn-N-GQDs was selectively "Turned Off" by Cu2+ via a static quenching setup. Remarkably, quenched fluorescence was surprisingly reactivated upon adding quinalphos to the quench setup, indicating a direct correlation between luminescence reactivation and quinalphos concentration. Briefly, this phenomenon is ascribed to the functional groups in quinalphos, such as quinoxalinyl and phosphorothioate, which chelate with Cu2+ ions, disrupting the nonfluorescent Cu2+-Co/Zn-N-GQDs complex. The design sensor demonstrated a limit of detection (LOD) of 0.11 μM and a broad linear span of 0.5 to 200 μM. In conclusion, Cu2+-Co/Zn-N-GQDs sensor showed immediate applicability, stability, and reproducibility, making it highly effective for quinalphos sensing in various samples.

A spatiotemporal comparison of interobserver error in vegetation sampling

AbstractQuestionsWe asked how interobserver error in sampling vegetation (excluding trees) varied over time, space and habitat type; determined whether there were any obvious correlates of observer error; and evaluated evidence of bias among observers.LocationNine national park units in the Midwestern USA.MethodsWe quantified observer error in the context of a long‐term monitoring program employing three observers, evaluating interobserver error across 11 locations in the Midwestern USA over five years. The vegetation (excluding trees) was sampled independently by two teams of observers at prairie and woodland locations (n = 94 plots total).ResultsTotal pseudoturnover ranged between 20.2% and 22.1% at prairie locations, and between 16.8% and 28.6% at woodland locations. The overlooking component of pseudoturnover accounted for 75% or more of total pseudoturnover, with misidentification and cautious components each contributing 19% or less of the total, depending on location. The percentage of comparisons in which both observers recorded the same cover class ranged from 71.3% to 78.5% at the prairie locations and 56.9% to 85.6% at woodland locations. When observers did not agree on cover class, they were off by more than one class less than 6% of the time. Overlooking error was more likely to occur for species with less cover, while estimation error was more likely to occur for species with greater cover. A bias existed among observers, as the least experienced observer recorded 6.2%–11.8% more species than the other two observers. Interobserver bias also existed for rates of estimation error, as one observer consistently recorded higher cover classes.ConclusionsObserver error is a pervasive aspect of vegetation sampling. Continued training and experience yielded limited increases in precision. Elements of the sampling design probably reduced observer error to a certain degree, although some level of interobserver error in vegetation surveys is unavoidable.

Re-using an oleic by-product in the manufacturing of fired clay bricks

BackgroundThe high demand for building bricks underscores their essential role in the construction industry, which pushes researchers to continuously improve the characteristics of these products. This study aimed to investigate the impact of incorporating oleic components (Margins) in fired bricks manufacturing of by substituting water with different percentages of margins. MethodsFired bricks were produced at the laboratory using clays taking from the Tangier region in northern Morocco. During this process, water used in the bricks production was substituted with margins in increasing percentages ranging from 10 % up to 30 %. To validate the results obtained from the physicochemical analyses performed on the manufactured bricks, three types of vegetable samples from three different regions of Morocco were utilized. ResultThe study results are very remarkable, demonstrating a significant enhancement in compressive strength. The strength increased from 15.16 MPa for conventional bricks to 33.77 MPa for bricks manufactured with a 30 % substitution. Furthermore, porosity decreased from 33 % to 19 %. ConclusionBy integrating oleic components into the manufacturing process, we were able to achieve three main objectives.1. We have improved the characteristics of the bricks, which tend towards the load-bearing wall standards.2. We reduced the water quantity used in the bricks manufacturing by 30 %.3. We minimized the processing cost of the waste resulting from olive oil production, as well as its harmful effects on the environment.

Assessment of bacteriological quality of fruits and vegetables sold in Gombe metropolitan market

Fruits and vegetables are important components of human diet that could be contaminated by different kinds of microorganisms. Microbial contamination may occur during any steps of transportation or processing from farm-to-table due to many environmental, animal, and human sources as well as technological applications. This study aimed at assessing the bacteriological contaminants of fruits and vegetables sold in Gombe metropolitan. A total of 30 fruits and vegetables samples were purchased from different vendors and transported to the Microbiology Laboratory for processing. Ten-fold serial dilution was performed on each sample and aliquots of 10-1-10-3 dilutions were inoculated on Nutrient Agar and MacConkey Agar plates using pour-plate technique. The plates were incubated for 24 hours at 37oC and then observed for aerobic mesophilic and faecal coliform counts. The bacterial loads of the samples ranged from 3.7x104 to 2.7x105 and 2.9x104 to 8.7x104 for total mesophilic and faecal coliform counts, respectively. Subsequently, a total of eight bacteria were isolated and identified as Escherichia coli, Salmonella spp., Klebsiella spp., Enterobacter spp., Pseudomonas spp., Staphylococcus aureus, Bacillus cereus, and Shigella spp. In conclusion, the fruits and vegetables were found to be contaminated with different bacterial species of public health concern.