4-day Test Research Articles

Interlaboratory Comparison of Three Sediment Bioaccumulation Tests

Standard bioaccumulation tests are commonly conducted using Macoma nasuta (clam), and Alitta virens (polychaete) for marine tests, and Lumbriculus variegatus (an oligochaete) for freshwater tests. Because the interlaboratory variability associated with these tests is unknown, four experienced laboratories conducted standard 28‐day bioaccumulation tests with the above species using sediments contaminated with polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). Chemical analysis of tissue samples was performed by a single laboratory. The intralaboratory variance among replicates was relatively low for PCB tissue concentrations, with coefficients of variation (CVs) ranging from 9% to 28% for all laboratories and species, with the exception of one laboratory reporting higher variability for L. variegatus (CV = 51%). Intralaboratory variance for PCB tissue concentrations was higher than interlaboratory variance for A. virens and L. variegatus, and the magnitude of difference (MOD) for laboratory means ranged from 1.4 to 2.0 across species. Intralaboratory variability was also low for lipid content, and lipid normalization of PCB and PAH body residues generally had little impact on variability. In addition to variability across bioassay laboratories, analytical variability was evaluated by different laboratories measuring the concentration of PCBs and total lipids in a subsample of tissue homogenate of sediment‐exposed test organisms. Variability associated with tissue analysis was higher than bioassay laboratory variability only in tests with L. variegatus. Statistical differences between samples may be observed due to the low intralaboratory variability; however, the biological significance of these differences may be limited because the MOD is low. Considering the MOD when comparing bioaccumulation across treatments accounts for uncertainty related to inherent variability of the test in the interpretation of statistically significant results. Environ Toxicol Chem 2022;41:1260–1275. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Chronic toxicity effects of sediment-associated polystyrene nanoplastics alone and in combination with cadmium on a keystone benthic species Bellamya aeruginosa

Nanoplastics (NPs) are emerging pollutants that may adversely affect aquatic fauna. However, the adverse effects of NPs and heavy metals, both alone and combined on freshwater benthic fauna remain largely unclear. Here, we performed a 28-day sediment toxicity test with Bellamya aeruginosa to examine the effects of exposure to polystyrene nanoplastics (PSNPs) and co-exposure to PSNPs and Cd. Cd bioavailability, the bioaccumulation of PSNPs and Cd, and changes in multiple biomarkers were determined. The results revealed that PSNPs significantly increased Cd bioavailability and thereby facilitated Cd bioaccumulation; however, PSNPs displayed a negligible vector role in Cd uptake by B. aeruginosa. The results demonstrated that PSNPs can accumulate in B. aeruginosa and induce oxidative damage and DNA damage. Co-exposure to PSNPs and Cd significantly enhanced oxidative damage and DNA damage and reduced metallothionein levels. The integrated biomarker response index analysis showed that co-exposure to PSNPs and Cd considerably increased toxic stress in B. aeruginosa compared to single PSNPs or Cd exposure, suggesting that PSNPs may have a synergistic effect with Cd. Collectively, our findings highlight that PSNPs not only cause toxicity to B. aeruginosa but also significantly enhance the toxicity of Cd by increasing Cd bioavailability in the sediment.

EFFECT OF COMPACTION TIME WITH VIBRATING HAMMER ON STRENGTH PROPERTIES IN ROLLER COMPACTED CONCRETE

Roller compacted concrete (RCC) production in the laboratory using a vibrating hammer is one of the methods used in research studies. In this method, it is thought that the compaction time will change the strength properties of the RCC samples. For this reason, it is aimed to determine the ideal compaction time in terms of strength by producing RCC samples with different compaction times. In the experimental study, RCC samples with the same mixture design were compacted with a vibrating hammer for 5, 10, 15 and 20 seconds at different times. Compactibility percentage, unit weight, water absorption, ultrasonic pulse velocity and 28-day concrete compressive strength tests were carried out on the produced roller compacted concrete samples. In the study, it was determined that the void ratio in the roller compacted concrete samples decreased with the increase of the compaction time. The highest strength value was obtained from the RCC sample, which was compressed for 15 seconds. It has been emphasized that the design of the roller compacted concrete mix and especially its consistency will affect the ideal compaction time in terms of strength.

Exercise Effects on Motor Skill Consolidation and Intermuscular Coherence Depend on Practice Schedule.

Cardiorespiratory or aerobic exercise immediately after practice of an upper-extremity motor skill task can facilitate skill consolidation, as demonstrated by enhanced performances at 24 h and 7-day retention tests. The purpose of this study was to examine the effect of acute cardiorespiratory exercise on motor skill consolidation when skill practice involved low and high levels of contextual interference introduced through repetitive and interleaved practice schedules, respectively. Forty-eight young healthy adults were allocated to one of four groups who performed either repetitive or interleaved practice of a pinch grip motor sequence task, followed by either a period of seated rest or a bout of high-intensity interval cycling. At pre- and post-practice and 24 h and 7-day retention tests, we assessed motor skill performance and β-band (15–35 Hz) intermuscular coherence using surface electromyography (EMG) collected from the abductor pollicis brevis and first dorsal interosseous. At the 7-day retention test, off-line consolidation was enhanced in the cardiorespiratory exercise relative to the rest group, but only among individuals who performed interleaved motor skill practice (p = 0.02). Similarly, at the 7-day retention test, β-band intermuscular coherence increased to a greater extent in the exercise group than in the rest group for those who performed interleaved practice (p = 0.02). Under the present experimental conditions, cardiorespiratory exercise preferentially supported motor skill consolidation and change in intermuscular coherence when motor skill practice involved higher rather than lower levels of contextual interference.

Combined toxic effects of thiamethoxam on intestinal flora, transcriptome and physiology of Pacific white shrimp Litopenaeus vannamei

The environmental accumulation of thiamethoxam has increasingly become a risk for the health of aquatic animals, especially crustacean species in the same phylum as the target pests. The lack of knowledge on the toxicity of thiamethoxam to crustaceans motivates our research to study the acute and chronic toxicity of decapod crustaceans Litopenaeus vannamei, exposed to thiamethoxam. A 28-day chronic toxicity test followed a 96 h acute toxicity test. Thiamethoxam induced oxidative stress and decreased growth performance in shrimp. In addition, thiamethoxam has led to a substantial imbalance of the micro-ecosystem in the intestine. The composition of the intestinal flora changed significantly, and the balance of the interaction network in genera was broken. The competitive interaction of many bacteria becomes an unstable cooperative interaction. Transcriptomic analysis showed that the numbers of up- and down-regulated differentially expressed genes (DEGs) increased in a dose-dependent manner. These DEGs were significantly enriched in pathways related to detoxification, and the expression of most detoxification genes was upregulated. DEGs related to detoxification were positively correlated with Shimia and negatively correlated with Pseudoalteromonas. This study provides evidence for the first time on the toxic effects of thiamethoxam on the growth, biochemistry, intestinal flora, and transcriptome in crustaceans.

Feasibility study of a prototype extended-wear insulin infusion set in adults with type 1 diabetes.

To assess the feasibility of a prototype insulin infusion set (IIS) for extended wear in adults with type 1 diabetes. The prototype Capillary Biomedical investigational extended-wear IIS (CBX IIS) incorporates a soft, flexible, reinforced kink-resistant angled nylon-derivative cannula with one distal and three proximal ports to optimize insulin delivery. Twenty adult participants with type 1 diabetes established on insulin pump therapy used the CBX IIS for two 7-day test periods while wearing a Dexcom G5 continuous glucose monitor. Participants were able to wear the CBX IIS for an average of 6.6 ± 1.4 days. Eighty-eight percent (36 of 41) of sets were worn for 7 days. No serious adverse events were reported. Five infusion sets failed prematurely because of: unresolvable hyperglycaemia (three); hyperglycaemia with elevated ketones (one); or infection (one). Median time in range (3.9-10.0 mmol/L) was 62% (54-76). Average glucose levels per day of infusion set wear showed a statistically significant increase over time (p < .001). Our preliminary observations confirm the tolerability of the prototype CBX IIS for extended wear, albeit with a deterioration in glucose control after the third day.

Layer-by-layer aided β-cyclodextrin nanofilm for precise organic solvent nanofiltration

Synthetic interlayers with multiple functions and structural stability have a high potential to construct novel thin film composite (TFC) membranes with demanding permselective property for precise separations. Herein, a functional interlayer derived from the polyelectrolyte-based layer-by-layer (LBL) self-assembly is reported to prepare interlayer engineered organic solvent nanofiltration (OSN) membranes using β-cyclodextrin (β-CD) as a monomer via interfacial polymerization (IP) process. Compared to the interlayer-free OSN membrane, a smoother selective layer with higher crosslinking degree is obtained for our developed membranes, enabling an improved organic dye rejection (e.g., 91.9% for methyl orange and 98.8% for brilliant blue R). Importantly, the LBL-aided β-CD nanofilm exhibits competitive permeances towards both polar (e.g., methanol, 5.8 LMH/bar) and nonpolar solvents (e.g., hexane, 7.0 LMH/bar). These performances can be attributed to the multiple roles of LBL-based interlayer as preventing the intrusion of selective layer and creating dual linkages (i.e., amide and ester), along with tailoring the physicochemical properties of caped β-CD nanofilm. Besides, the newly developed OSN membrane can discriminate between dye molecules with similar molecular weights and same charge but different molecular configurations. Meanwhile, its good structural integrity and long-term stability are also demonstrated by the 7-day filtration test using tetracycline in methanol and β-carotene in hexane, respectively, as evidence of constant solute rejections (≥90%) during the entire filtration process. This work unravels the functions of LBL-based interlayer in enhancing the OSN performance, offering new insights into shaping the development of interlayer engineered OSN membranes for real-life applications.

Onsite measurement and performance analysis of capillary heat pump system used in subway tunnels

This study proposed a ground source heat pump system using capillary networks as the front-end heat exchanger, to alleviate thermal pollution and utilize waste heat generated in subway tunnels and the surrounding rock. We conducted onsite measurement of the capillary ground source heat pump system based on a real engineering project involving a subway tunnel. Subsequently, the heat transfer performance of the capillary heat exchanger and energy efficiency of the system were analyzed. The heat transfer capacity of the capillary heat exchanger was approximately 45–80 and 100–110 W/m2 in a test with a duration of 7 h in winter and a test with a duration of 14 h in summer, respectively. The average coefficient of performance of the heat pump unit and coefficient of performance of the system were 3.72 and 3.18, respectively, in winters, and 3.19 and 2.64, respectively, in summers. Under a 4-day test with an intermittent operation of 8 h per day in summer, the performance of the system was improved and remained stable for four days during the test. The average coefficient of performance of the heat pump unit and of the system for intermittent operation were 3.67 and 2.96, respectively, which were larger than those for 14 h continuous operation in summer. In practical applications, intermittent operation or additional auxiliary cooling sources are recommended in summer conditions.

Evaluation of the inhalation toxicity of arecoline benzoate aerosol in rats.

Arecoline is a pharmacologically active alkaloid isolated from Areca catechu. There are no published data available regarding the inhalation toxicity of arecoline in animals. This study aimed to evaluate the inhalation toxicity of arecoline in vitro and in vivo. For this purpose, arecoline benzoate (ABA) salt was prepared to stabilize arecoline in an aerosol. The MTT assay determined the half-maximal inhibitory concentration values of ABA and arecoline in A549 cell proliferation to be 832 and 412 μg/ml, respectively. The toxicity of acute and subacute inhalation in Sprague-Dawley rats was evaluated using the guidelines of the Organization for Economic Cooperation and Development. For acute inhalation, the median lethal concentration value of ABA solvent was >5175 mg/m3 . After the exposure and during the recovery period, no treatment-related clinical signs were observed. In the 28-Day inhalation toxicity test, daily nose-only exposure to 2510 mg/m3 aerosol of the ABA solvent contained 75 mg/m3 ABA for male rats and 375 mg/m3 ABA for female rats, which caused no observed adverse effects, except for the decreased body weight gain in male rats exposed to 375 mg/m3 ABA. In this study, the no observed adverse effect level (NOAEL) for the 28-day repeated dose inhalation of ABA aerosol was calculated to be around 13 mg/kg/day for male rats and 68.8 mg/kg/day for female rats, respectively.

A Digital Health Application Allowing a Personalized Low-Glycemic Nutrition for the Prophylaxis of Migraine: Proof-of-Concept Data from a Retrospective Cohort Study.

Background: Migraine is a headache disorder with the highest socioeconomic burden. The aim of this study was to deliver the first proof-of-concept data of the potential role of an individual low-glycemic diet provided by a novel digital health application in the prophylaxis of migraine. Methods: We analyzed data from a retrospective survey of individuals who participated in a digital nutrition program that provides dietary recommendations based on the individual analysis of continuous glucose measurement from an up to 14-day test phase. A total of 84 individuals completed the retrospective digital survey. The endpoints were changes in the number of migraine days, average duration of attacks, average pain severity, frequency of intake of pain medication, absenteeism, and presenteeism before and after program participation. Results: The intraindividual comparisons of the endpoints before and after program participation revealed decreases in migraine frequency and other patient-relevant migraine parameters. Moreover, patients with a baseline migraine frequency of two and more migraine days per month and adherence to the dietary recommendations (n = 40) showed a mean reduction in migraine days by 33% with a 50%-responder rate of 38%. Conclusions: The data provides emerging evidence that an individualized low-glycemic diet based on continuous glucose measurement could be a promising approach for a diet-based, non-pharmacological migraine prophylaxis. However, future research is required to confirm the implied effectiveness.

Selection of formulated sediment and feeding condition for 10-day spiked-sediment toxicity test with estuarine amphipod Grandidierella japonica

This study was performed to select formulated sediment with appropriate feeding conditions for the evaluation of estuarine sediment toxicity. Grandidierella japonica, which inhabits seawater worldwide, was examined for 10-day survival, and the repeatability was evaluated under nine test conditions. The formulated sediment feeding condition combined with the highest survival rate was applied to evaluate fluoranthene toxicity in the sediment. The KB-T10 feeding condition showed the highest survival rate of 93.5%, with sufficient repeatability (4.6%). In the fluoranthene spiked-sediment toxicity test, the estimated LC50 (95% significance level) was successfully achieved under the KB-T10 condition but not under the OE-T10 condition. Therefore, we propose the use of TetraMin® (1 mg/org./day) and Kemble sediment in 10-day static spiked-sediment toxicity tests with G. japonica. Further improvements are needed for OECD sediment in seawater to increase the survival rate and prevent chemical loss due to overlying water renewal.

The Effects of Roux-en-Y Gastric Bypass on Glucose- vs. Fructose-Associated Conditioned Flavor Preference

In rodents, repeated single-bottle exposures to distinctly flavored isocaloric glucose and fructose solutions, two sugars with different metabolic pathways, eventually lead to a preference for the former. Because Roux-en-Y gastric bypass (RYGB) surgery decreases preference for and intake of sugar solutions in rats, we tested whether RYGB would curtail the conditioning of a preference for a glucose-paired vs. fructose-paired flavor. RYGB (♂ n=11; ♀ n=10) and sham-operated (SHAM; ♂ n=9; ♀ n=10) rats were trained with a single bottle (30 min/day) containing 8% glucose solution flavored with either 0.05% grape or cherry Kool-Aid (Glu/CSG) or 8% fructose solution with the alternative Kool-Aid flavor (Fru/CSF) in an alternating fashion for 8 days. To determine baseline preferences, a 4-day 30-min two-bottle test was used to assess preference for Glu/CSG vs. Fru/CSF before training. After training, 2-day 30-min two-bottle tests assessed preference for the a) Glu/CSG (CSG-flavored 8% glucose solution) vs Fru/CSF (CSF-flavored 8% fructose solution), b) CSG- vs. CSF-flavored mixture of 4% glucose & 4% fructose (isocaloric), c) CSG- vs. CSF-flavored 0.2% saccharin (“sweet”, no calories), and d) CSG- vs. CSF-flavored water. During training, only male SHAM rats demonstrated progressively increased intake of Glu/CSG over Fru/CSF, and female SHAM rats displayed a trend. RYGB eliminated any difference in single-bottle intake of these solutions during training, regardless of sex. Like their male and female SHAM counterparts, male RYGB rats displayed a conditioned preference for the CSG-associated stimulus in Tests 1-3. Although female RYGB rats displayed acquisition of the conditioned flavor preference in Test 1, unlike the other groups, when the differential sugar cue between the two solutions was removed in Tests 2 and 3, female rats did not display a CSG preference. When the sugar and sweetener cues were both removed on Test 4, all groups displayed some generalization decrement. Thus, RYGB does not compromise the ability of rats to learn and express a glucose- vs. fructose-associated conditioned flavor preference when the exact CS used in training is presented in testing. The mechanistic basis for the sex difference in the effect of RYGB on the generalization decrement observed in this type of flavor preference learning warrants further study.

Genome analysis of Bacillus subtilis JCL16 and the synergistic relationship among its metabolites reveal its potential for biocontrol of Nocardia seriolae

Nocardia seriolae is one of the major causative agents of fish nocardiosis, responsible for large-scale fish die-offs and economic losses in the aquaculture industry worldwide. Therefore, research efforts towards developing efficacious alternatives to aquatic antibiotics, such as vaccines, immunomodulatory additives including aquatic probiotics, to control this disease are of high importance. Recently, we isolated a soil-derived strain of Bacillus subtilis JCL16, and the 21-day challenge tests results showed that the addition of B. subtilis JCL16 culture to the basal control diet significantly increased the survival rate of largemouth bass with nocardiosis from 21.67% to 68.3%. To reveal the putative functional factors, we determined the genome sequence of B. subtilis JCL16 using PacBio RS II and Illumina HiSeq 4000 platform, and predicted its secondary metabolites using antiSMASH, which showed that it contains 11 functional gene clusters, three of which, srf, bac and sbo, have previously been verified to have antagonistic bacterial functions. Subsequently, mutants Δsrf, Δbac, Δsbo were constructed using homologous recombination techniques, and HPLC results further elucidated that the three gene clusters are responsible for the synthesis of surfactin, bacilysin and subtilosin A, respectively. To our surprise, a significant reduction in the inhibition of N. seriolae occurred in all three mutants compared to the wild type, so we speculated that surfactin, bacilysin and subtilosin A might have adopted a synergistic strategy. Next, we prepared their pure products and further confirmed our inference by Oxford Cup and MIC assays.In summary, the good biocontrol effect of B. subtilis JCL16 against fish Nocardia is likely due to the synergistic strategy among surfactin, bacilysin and subtilosin A. Here we propose a synergistic mechanism among them, which provides some insight into the powerful biocontrol mechanisms of Bacillus.

Assessment of the activities of Chasmanthera dependens Hochst. combined with other plants on chloroquine-sensitive and chloroquine-resistant Plasmodium berghei

The prevalence of Plasmodium strains resistant to conventional monotherapy drugs has necessitated the need for more effective and affordable antimalarial agents. This study aimed at evaluating the antimalarial activities of some indigenous plants alone and in combination with chloroquine with a view to proffering herbal combination therapy as an alternative to the currently used antimalarial combination therapy. Extracts obtained separately from the decoctions of the roots of Chasmanthera dependens Hochst. (Menispermaceae), Vernonia amygdalina Delile (Asteraceae) and methanol extract of Sphenocentrum jollyanum Pierre (Menispermaceae) leaf were analysed by high resolution liquid chromatography-mass spectrometry and evaluated for repeated-dose oral toxicity in mice using standard protocols. Assessments of C. dependens and V. amygdalina with their combination were carried out on chloroquine-sensitive Plasmodium-infected mice with the 4-day chemosuppressive antimalarial test. Sphenocentrum jollyanum, C. dependens and their combinations with chloroquine (10 mg/kg) were assessed on chloroquine-resistant Plasmodium using the curative test model. The combination of C. dependens and V. amygdalina exhibited chemosuppression (71.1±3.7%) that was not significantly (p>0.05) different from chloroquine (80.1±1.9%). In the curative model, a significant parasite clearance (98.2%) was observed with the combination of C. dependens and chloroquine. The study concluded that the aqueous root extracts possessed potent antimalarial activity in chloroquine-sensitive malaria infection. It also revealed an additive interaction between C. dependens and chloroquine that could be further investigated as a herbal combination for chloroquine-resistant malaria.

Validation and test\u2013retest repeatability performance of parametric methods for [11C]UCB-J PET

[11C]UCB-J is a PET radioligand that binds to the presynaptic vesicle glycoprotein 2A. Therefore, [11C]UCB-J PET may serve as an in vivo marker of synaptic integrity. The main objective of this study was to evaluate the quantitative accuracy and the 28-day test–retest repeatability (TRT) of various parametric quantitative methods for dynamic [11C]UCB-J studies in Alzheimer’s disease (AD) patients and healthy controls (HC). Eight HCs and seven AD patients underwent two 60-min dynamic [11C]UCB-J PET scans with arterial sampling over a 28-day interval. Several plasma-input based and reference-region based parametric methods were used to generate parametric images using metabolite corrected plasma activity as input function or white matter semi-ovale as reference region. Different parametric outcomes were compared regionally with corresponding non-linear regression (NLR) estimates. Furthermore, the 28-day TRT was assessed for all parametric methods. Spectral analysis (SA) and Logan graphical analysis showed high correlations with NLR estimates. Receptor parametric mapping (RPM) and simplified reference tissue model 2 (SRTM2) BPND, and reference Logan (RLogan) distribution volume ratio (DVR) regional estimates correlated well with plasma-input derived DVR and SRTM BPND. Among the multilinear reference tissue model (MRTM) methods, MRTM1 had the best correspondence with DVR and SRTM BPND. Among the parametric methods evaluated, spectral analysis (SA) and SRTM2 were the best plasma-input and reference tissue methods, respectively, to obtain quantitatively accurate and repeatable parametric images for dynamic [11C]UCB-J PET.

Evaluation of the toxic effects of the aqueous extract of Niprineem tea in mice and rats

Azadirachta indica is an important plant in traditional complementary and alternative medicine with decoctions (tea) being a common mode of administration. Herbal teas are frequently self-administered thus the need to prepare a standardized dosage form for the administration of such decoctions. The leaf of Azadirachta indica was formulated for administration as tea; thus, this study was designed to determine the safety profile of Niprineem tea. Oral acute and sub-chronic toxicity studies of the aqueous extract of Niprineem tea (NTE) were evaluated. The OECD (No 423) limit test was followed to determine the LD50 in Swiss albino mice, while OECD 407 guideline was used for the sub-chronic toxicity studies in Wistar rats. Acute administration of NTE did not cause detectable signs of toxicity in treated animals and no mortality was recorded. In the 28-day toxicity tests, there were no significant (p&lt;0.05) changes in food and water intake, or urine and faecal output. Haematological analysis did not show deleterious effects in treated rats. Biochemical evaluation of indicators for renal and hepatic functions did not show significant changes after treatment with NTE. Likewise, histological tests did not result in structural changes in cells of the tissues of major organs. The results obtained suggest that Niprineem tea is relatively non-toxic and safe at the tested dose.

Quarantine and testing strategies to ameliorate transmission due to travel during the COVID-19 pandemic: a modelling study.

SummaryBackgroundNumerous countries have imposed strict travel restrictions during the COVID-19 pandemic, contributing to a large socioeconomic burden. The long quarantines that have been applied to contacts of cases may be excessive for travel policy.MethodsWe developed an approach to evaluate imminent countrywide COVID-19 infections after 0–14-day quarantine and testing. We identified the minimum travel quarantine duration such that the infection rate within the destination country did not increase compared to a travel ban, defining this minimum quarantine as “sufficient.”FindingsWe present a generalised analytical framework and a specific case study of the epidemic situation on November 21, 2021, for application to 26 European countries. For most origin-destination country pairs, a three-day or shorter quarantine with RT-PCR or antigen testing on exit suffices. Adaptation to the European Union traffic-light risk stratification provided a simplified policy tool. Our analytical approach provides guidance for travel policy during all phases of pandemic diseases.InterpretationFor nearly half of origin-destination country pairs analysed, travel can be permitted in the absence of quarantine and testing. For the majority of pairs requiring controls, a short quarantine with testing could be as effective as a complete travel ban. The estimated travel quarantine durations are substantially shorter than those specified for traced contacts.FundingEasyJet (JPT and APG), the Elihu endowment (JPT), the Burnett and Stender families’ endowment (APG), the Notsew Orm Sands Foundation (JPT and APG), the National Institutes of Health (MCF), Canadian Institutes of Health Research (SMM) and Natural Sciences and Engineering Research Council of Canada EIDM-MfPH (SMM).

Multiple Regression Models for Compressive and Flexural Strength of Recycled Printed Circuit Board Concrete

Printed circuit board (PCB) waste is becoming a major environmental and human health concern. PCB trash disposal is becoming a significant issue. In the building industry, there is the possibility to use new technology to recycle huge quantities of printed circuit board waste material. The civil engineer is compelled to look for a cheaper aggregate source since the extra expense has increased. Minimize electronic trash on the planet and the material used in building by implementing printed circuit boards. PCB waste concrete’s compressive and flexural strengths will be examined in this study. The concrete’s compressive and flexural properties were conducted using a printed circuit board as a coarse aggregate substitute. When using a water-cement ratio of 0.50 for M30 concrete, certain common cubes lose between 5 and 25 percent of aggregate. Seven and 28-day tests are used to see how PCB waste material impacts concrete cubes and beams’ compressive and flexural strengths. The association between the PCB waste concrete and the regression analysis is determined. The most precise regression model is obtained utilizing several regression equations, such as multiple regression equations.

Acute toxicity and 28-day repeated dose studies of multi-walled carbon nanotubes

In the light of the increased production and use of multi-walled carbon nanotube (MWCNT) in consumer products, there is a need for screening the potential toxicity of this nanomaterial. In the present study, the researchers have investigated the acute dermal and acute eye irritation in rabbits and acute oral irritation and 28-day repeated administration of MWCNT in rats. A single dose of 5000 mg/kg was used to test Albino Rabbits for acute dermal and eye irritation test. Similar dose was given to Sprague Dawley Rats for the acute oral and 28-day repeated dose test. Clinical signs/manifestations were closely observed for the first four (4) hours post sample administration and was continued for 1,2,3,7 and 14-day observation period. In acute toxicity study, no treatment-related death or toxic signs were observed with MWCNT. In the 28-day repeated dose study, no significant differences in hematology and clinical biochemistry were detected between control and MWCNT. However, histopathology results revealed mild periarteriolar lymphoid cell depletion in the spleen and mild tubular cell degeneration on the cortex and medulla of both kidneys of the rats while no remarkable lesions were seen on the other organs of both female and male rats.

Safety Assessment of Canola Oil Extracted by Aid of Pulsed Electric Field: Genetic, Acute and Subacute Toxicity

Pulsed electric field (PEF) is a nonthermal technology resulting in the rupture of cell membranes and increasing the electrical conductivity and the permeability of intracellular material. There was little work about the safety of food treated by PEF. The acute, subacute oral, and genetic toxicities were investigated to explore the safety of canola oil extracted by aid of PEF treatment (PTCO). The results showed that no negative consequences were caused by PEF. PTCO was regarded as practically non-toxic with a LD50 higher than 40 g/kg bw. No oil intake-related mortality, clinical, weight gain and organ coefficient abnormalities were observed. The histopathological symptoms indicated a mild load but not obvious toxicities on liver and kidney. The 28-day subacute toxicity test confirmed that less than 10 g/kg·d bw of oil intake did not exhibit any intake-related changes in physical, physiological, biochemical, hematological, and histopathological signs. The less than 4 of atherosclerosis index suggested that no risk of cardiovascular disease caused by PTCO intake. It was speculated that the PEF treatment would not cause any safety issues to food products.