Removal Of Residues Research Articles

Preparation of β-cyclodextrin-reduced graphene oxide aerogel and its application for adsorption of herbicides

Herbicides are the primary pesticides that can easily pollute water bodies, attracting significant attention from researchers regarding the effective removal of herbicide residues from the water environment. In this study, a β-cyclodextrin-reduced graphene oxide (β-CD-BTCA-rGO) aerogel was prepared following the self-assembly hydrothermal method using 1,2,3,4-butane tetracarboxylic acid (BTCA) as crosslinkers. The self-assembly process involved the cross-linking of “soft” β-cyclodextrin (β-CD) with “hard” graphene oxide (GO) nanosheets, forming a stable β-CD-BTCA-rGO aerogel. The prepared β-CD-BTCA-rGO aerogel demonstrated excellent adsorption performance. The adsorption capacities were 62.3 and 46.8 mg/g for sulfentrazone and quinclorac, respectively, surpassing the traditional reduced graphene oxide (rGO) aerogel and citric acid cross-linked (β-CD-CA-rGO) aerogel. Correspondingly, its adsorption capacity for quinclorac was 1.8 times and 12 times that of rGO aerogel and β-CD-CA-rGO aerogel, respectively. Quantum chemical calculations at the density functional theory (DFT) level, utilizing the Fukui function to predict chemical reaction sites, indicated that BTCA, as crosslinkers, formed stable chemical bonds (ester bonds) with GO through hydroxyl and carboxyl surface functional groups, leading to the formation of stable porous aerogels. Furthermore, the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energy gap was quantitatively measured for various adsorption mechanisms, revealing that electrostatic adsorption was the main force of the adsorption on the aerogels. The β-CD-BTCA-rGO aerogels prepared in this study demonstrated economic feasibility as adsorbents and exhibited good reproducibility. Consequently, β-CD-BTCA-rGO aerogels hold promising application prospects in the remediation of pesticide pollution in water systems.

Removal of pesticide residues from vegetables by hydrogen peroxide assisted ultrasonic process

This study addresses the concern of pesticide residues in vegetables by exploring the hydrogen peroxide assisted ultrasonic (H2O2/US) process for the removal of six pesticides from pakchoi, a popular green vegetable in China. Remarkably high efficiency was achieved, with removal rates reaching 83.9%, 68.8%, 85.9%, 91.6%, 75.6%, and 73.4% for dimethoate, dichlorvos, methiocarb, propoxur, chlorobenzuron, and etridiazole, respectively, through the H2O2/US process. A notable synergy was observed in the coupled H2O2/US process. The analysis of mass balance and degradation pathways indicates that the synergy stemmed from the efficient oxidation of pesticides by hydroxyl radicals (HO•) formed via sonolysis of H2O2. Surface properties of vegetables showed great impacts on pesticide removal by H2O2/US. Despite these treatments, the H2O2/US process exhibited minimal impact on vegetable quality. Overall, this study underscores the potential of the H2O2/US process as a promising technology for effectively removing pesticides from vegetables.

Synthesis, characterization of FeNi3@SiO2@CuS for enhance solar photocatalytic degradation of atrazine herbicides: Application of RSM

This study was focused on the response surface methodology modeling (RSM) for the removal of Atrazine residue (ATZ) using nanocomposite. The FeNi3@SiO2@CuS nanocomposite was fabricated by co-precipitation and sol-gel methodologies, and their properties were studied by XRD, FTIR, VSM, and SEM techniques. The synthesis core-shell composite was used to degrade atrazine herbicide (ATZ) from synthetic wastewater. The efficiency of FeNi3@SiO2@CuS was calculated as a function of different input parameters (pH, ATZ concentration, catalyst concentration, H2O2 concentration, and reaction time by using a central composite design (CCD) adapted from response surface methodology. The CCD created a matrix of 60 runs of the experiment to look into how the five input elements interacted with one another. A reduced quadratic model was created using the findings and demonstrated good predictability of outcomes consistent with the research findings. Variance analysis (ANOVA) indicated that the chosen model was highly significant (p < 0.0001), and the coefficients of determination R2, adjusted R2, and predicted R2 were 0.9587, 0.9513, and 0.9380, respectively, confirming that the second-order regression model had been satisfactorily adjusted to obtained data. Furthermore, the findings provide validation that the degradation rate of ATZ adheres to a pseudo-first-order kinetic model, exhibiting an impressive R2 value surpassing 0.98. Through the use of a numerical optimization technique, a 95.24 % ATZ elimination was represented by the desirability of 81.12 %. This study suggests that sunlight, catalyst, and H2O2 together have a significant influence on ATZ degradation. Additionally, RSM was an appropriate process for optimizing the factors related to the elimination of ATZ by a solar-induced photocatalytic process.

Cy3-Based Nanoviscosity Determination of Mucus: Effect of Mucus Collection Methods and Antibiotics Treatment.

The integrity of the protective mucus layer as a primary defense against pathogen invasion and microbial leakage into the intestinal epithelium can be compromised by the effects of antibiotics on the commensal microbiome. Changes in mucus integrity directly affect the solvent viscosity in the immediate vicinity of the mucin network, that is, the nanoviscosity, which in turn affects both biochemical reactions and selective transport. To assess mucus nanoviscosity, a reliable readout via the viscosity-dependent fluorescence lifetime of the molecular rotor dye cyanine 3 is established and nanoviscosities from porcine and murine ex vivo mucus are determined. To account for different mucin concentrations due to the removal of digestive residues during mucus collection, the power law dependence of mucin concentration on viscosity is used. The impact of antibiotics combinations (meropenem/vancomycin, gentamycin/ampicillin) on ex vivo intestinal mucus nanoviscosity is presented. The significant increase in viscosity of murine intestinal mucus after treatment suggests an effect of antibiotics on the microbiota that affects mucus integrity. This method will be a useful tool to assess how drugs, directly or indirectly, affect mucus integrity. Additionally, the method can be utilized to analyze the role of mucus nanoviscosity in health and disease, as well as in drug development.

Removal of antibiotic residue from aqueous solution by advanced oxidation process

Advanced oxidation processes are low-cost, highly efficient, and eco-friendly technologies in the removal of organic pollutants in wastewater using hydroxyl radicals for oxidation. Hydroxyl radicals possess high oxidation potential and can react with organic compounds, resulting in the complete mineralization of these compounds into carbon dioxide, water, and inorganic salt or their conversion into other compounds. The present investigation deals with the removal of tetracycline from water using simulated ultraviolet radiation and hydrogen peroxide, assessing the effect of operational parameters like the solution's initial pH, retention time, hydrogen peroxide dosage in terms of chemical oxygen demand (COD) removal from the standard aqueous solution of tetracycline. Results indicate that alkaline conditions and larger hydrogen peroxide dosage negatively affect the degradation. The removal efficiency of 68 % was achieved at 150 min of batch reaction under optimum conditions: pH = 4, and a dose of hydrogen peroxide of 0.3 ml per 100 ml of the solution to be treated. At optimum conditions, LC-MS/MS (liquid chromatography tandem mass spectrometry) analysis results showed a reduction in initial concentration of aqueous solution of tetracycline. Photocatalytic degradation followed pseudo-first-order kinetics with the rate constant (k) of 0.0061 min-1. Photocatalysis based on hydrogen peroxide is effective in the degradation of tetracycline in an aqueous solution and can be applied as a pretreatment of hospital wastewater containing tetracycline residues.

Bifenthrin Residues in Table Grapevine: Method Optimization, Dissipation and Removal of Residues in Grapes and Grape Leaves.

The QuEChERS method was adjusted to determine bifenthrin residues in grapes and grape leaves. Extraction and cleanup procedures were optimized to decrease co-extracted materials and enhance the detection of bifenthrin. The method was validated per the European Union (EU) Guidelines criteria. Accuracy ranged from 98.8% to 93.5% for grapes and grape leaves, respectively. Precision values were 5.5 and 6.4 (RSDr) and 7.4 and 6.7 (RSDR) for grapes and grape leaves, respectively. LOQs (the lowest spiking level) were 2 and 20 µg/kg for grapes and grape leaves, respectively. Linearity as determination coefficient (R2) values were 0.9997 and 0.9964 for grapes and grape leaves, respectively, in a matrix over 1-100 µg/L range of analyte concentration. This was very close to the value in the pure solvent (0.9999), showing the efficiency of the cleanup in removing the co-extracted and co-injected materials; the matrix effect was close to zero in both sample matrices. Dissipation of bifenthrin was studied in a supervised trial conducted in a grapevine field during the summer of 2023 at the recommended dose and double the dose. Dissipation factor k values were 0.1549 and 0.1672 (recommended dose) and 0.235 and 0.208 (double dose) for grapes and grape leaves, respectively. Pre-harvest interval (PHI) was calculated for the Maximum Residue Limit (MRL) values of the EU database. Residues of bifenthrin were removed effectively from grapes using simple washing with tap water in a laboratory study. Residues reached the MRL level of 0.3 mg/kg in both washing treatments, running or soaking in tap water treatments for 5 min. Removal from leaves did not decrease residue levels to the MRL in grape leaves.

Mechanistic study of cefixime degradation with an atmospheric air dielectric barrier discharge – Influence of radical scavengers and metal ion catalyst

The ineffective removal of antibiotic residues and their metabolites by conventional wastewater treatment setups lead to their continuous discharge into the environment, causing risks to both aquatic life and human health. This study explored the use of a non-thermal plasma (NTP) generated by atmospheric air for the degradation of cefixime (CFX), a widely consumed and recalcitrant antibiotic. This study achieved a complete degradation of CFX using an NTP technology in 8 min treatment time at 6 kV and 20 kHz applied AC voltage and frequency, respectively using a high voltage alternating current power supply unit. An energy yield of 0.42 g/kWh was estimated. The degradation of the pollutant was influenced by solution flow rate, applied voltage and the solution characteristics. Five degradation by-products were identified based on quadrupole time-of-flight (Q-TOF) mass spectrum (MS) analysis and a possible degradation pathway for the pollutant was proposed. Also, radical scavenger experiments were set up to understand the specific chemical species facilitating CFX degradation. The effect of Fe2+ catalyst on the degradation of CFX was investigated in the aqueous solution. This low-cost metal ion catalyst has been known to improve the degradation of organic compounds by facilitating the oxidizing power of H2O2. Considering this, a new idea was examined in this study which was the degradation of the antibiotic in the presence of both Fe2+ catalyst and some radical scavengers (iso-propyl alcohol – IPA, tert-butyl alcohol – TBA, and sodium hydrogen carbonate – NaHCO3). When Fe2+ was introduced into CFX solutions containing TBA, IPA and NaHCO3, respectively, the degradation and kinetics increased by at least 33 %. In these mixed additives, the degradation of the pollutant was enhanced by the consumption of H2O2.

Comprehensive toxicological, metabolomic, and transcriptomic analysis of the biodegradation and adaptation mechanism by Achromobacter xylosoxidans SL-6 to diuron.

Biodegradation was considered a promising and environmentally friendly method for treating environmental pollution caused by diuron. However, the mechanisms of biodegradation of diuron required further research. In this study, the degradation process of diuron by Achromobacter xylosoxidans SL-6 was systematically investigated. The results suggested that the antioxidant system of strain SL-6 was activated by adding diuron, thereby alleviating their oxidative stress response. In addition, degradation product analysis showed that diuron in strain SL-6 was mainly degraded by urea bridge cleavage, dehalogenation, deamination, and ring opening, and finally cis, cis-muconic acid was generated. The combined analysis of metabolomics and transcriptomics revealed the biodegradation and adaptation mechanism of strain SL-6 to diuron. Metabolomics analysis showed that after the strain SL-6 was exposed to diuron, metabolic pathways such as tricarboxylic acid cycle (cis, cis-muconic acid), glutathione metabolism (oxidized glutathione), and urea cycle (arginine) were reprogrammed in the cells. Furthermore, diuron could induce the production of membrane transport proteins in strain SL-6 cells and overexpress antioxidant enzyme genes, finally ultimately promoting the up-regulation of genes encoding amide hydrolases and dioxygenases, which was revealed by transcriptomics studies. This work enriched the biodegradation mechanism of phenylurea herbicides and provided guidance for the removal of diuron residues in the environment and promoting agriculture sustainable development.

Performance test and analysis of tetracycline degradation using a Micro-Nano Bubble system

Antibiotics and organic residues from Tetracycline (TC) and other pharmaceuticals administered to aquatic living organism have negative impacts on aquatic environment by killing-off non-target living organisms and developing antibiotic-resistant bacteria. In this study, Micro-Nano Bubble (MNB) system was used to remove TC residues. MNB system demonstrated good level of degradation efficiency, as resulted in experiment where in time of 100 min, the TC degraded at rate of 82.66% from its initial concentration of TC when the initial concentration was 1 mg/L. When the initial concentration was increased to 10 mg/L, MNB system degraded TC at 64.35% of their initial, this means MNB system demonstrated good level of efficiency for TC removal and indicated that it is more efficient in TC degradation under the conditions of low initial TC concentration and high availability of dissolved oxygen (DO). In the system as the temperature increased there was a significant decrease in DO saturation which was related to the TC complex structure that contain multiple function groups such as amino groups, hydroxyl and carboxyl which possess high strong affinity with oxygen that leads to their adsorption onto bubble surface. This study provides significant insights into the application of MNB system for the removal of organic residues within aquatic ecosystem and underscores the need for further exploration of MNB technology for environmental remediation.

64‐1: Protrusion‐free LTPS Using the CMP Process and Its OLED Application

Low Temperature Polysilicon (LTPS) is the most popular channel material used in the thin film transistor and it has the protrusions due to the volume expansion of Si and the presence of its native oxide. The protrusions cause the negative effects such as interface trap, hysteresis and so on. In that sense, the heights need to be lowered or eventually flattened.In this study, we used the chemical mechanical planarization (CMP) technique to reduce the surface roughness of LTPS to the 1nm and even lower. One of the most difficult problmes in the large sized CMP process is the removal of slurry residues after CMP and we successfully overcome the issue by using the hydrophilic angent.Finally, we are succesfully able to prepare AMOLED panel with reduced gate insulator thickness by using the CMP process and it shows less hysteresis results.

An Overview of the Degradation and Removal of Pesticide Residues from Water and Agricultural Runoff using Nanoparticles and Nanocomposites

: A high percentage of the applied chemicals on farmlands find their way into the water bodies and groundwater through agricultural runoff and leaching/percolation. Therefore, multiple remediation techniques need to be employed to deter the menace of pesticide residue contamination. Therefore, this review aimed to compute the most suitable degradation conditions for the removal of pesticide residue from water and agricultural runoff using nanomaterials. The review touches on the aspect of adsorption and photocatalytic degradation methods using nanomaterials and the most prominent factors that affect the degradation process. Information from recently published articles, book chapters, and conference proceedings were carefully studied and analyzed. It was revealed that heterogeneous photocatalysis shows the capability of complete mineralization of organic pollutants under optimum experimental conditions. Moreover, it is crucial to consider experimental conditions that could be applicable in the field to achieve a better result. It has been observed that integrating nanoremediation with other degradation methods to create a hybrid technique may play a crucial role in removing pesticide residues from agricultural runoff. However, the detrimental effects of the nanomaterials if any on the environmental matrices need to be taken under consideration to avoid the menace similar to plastic pollution as a result of extensive production and application of nanomaterials.

Causal inference and mechanism for unraveling the removal of four pesticides from lettuce (Lactuca sativa L.) via ultrasonic processing and various immersion solutions

This study explores the reduction of carbamates (CAs) and pyrethroids (PYs) − commonly used pesticides − in lettuce using various immersion solutions and ultrasonic processing. It also examines the role of machine learning and molecular docking in understanding the mechanisms of pesticide reduction. The results revealed that the highest reduction of both CAs and PYs exceeded 80 % on lettuce leaves. In most samples, the reduction increased with the power of ultrasonic processing and processing time. The results of machine learning models (XGBoost and SHAP) showed that during the immersion cleaning of CAs and PYs, as well as during both immersion cleaning and ultrasonic processing of CAs + PYs, the reduction was most influenced by the initial pesticide levels and immersion time. Gas Chromatography-Mass Spectrometry (GC–MS) analysis of lettuce’s wax layer identified 24 compounds, including fatty alcohols, fatty acids, fatty acid esters, and triterpenoids. Despite the absence of active sites, the lipophilic nature of long-chain aliphatic compounds aids in pesticide binding, while triterpenoids form strong hydrogen bonds with pesticides, indicating a robust adsorption on the lettuce surface. This study aims to offer insights into the efficient removal of chemical pesticide residues from fruits and vegetables, addressing critical concerns for food safety and human health.

Validation and efficacy of various decontamination solutions in eliminating acephate residues from okra

The experiments were carried out to validate an analytical method and to examine the impact of various decontaminating solutions on the removal of acephate residues from okra. Acephate analysis was performed using HPLC-UV, and sample extraction was done using the QuEChERS method. Method validation encompassed assessing specificity, linearity, precision, accuracy, as well as limits of detection (LOD) and quantification (LOQ). The method exhibited excellent linearity with R2 values ≥ 0.99. LOD and LOQ were determined at 0.5 µg mL−1 and 2 µg mL−1, respectively. The results indicated average recoveries ranging from 80.2% to 83.3% with a % RSD below 5%. The decontamination procedures include rinsing with running tap water, soaking in lukewarm water, 2% CH3COOH, 1% NaCl, 5% NaHCO3, 0.01% KMnO4, and in commercially available decontamination products such as nimwash, veggie clean, and arka herbiwash for a duration 10 minutes. Among all the treatments, soaking in nimwash solution showed remarkable effectiveness (96.75% removal), followed by veggie clean (94.97% removal) and arka herbiwash (95.80% removal). Washing okra samples in running tap water was found to be the least effective compared to other treatments.

Biodegradation of nitenpyram (neonicotinoid insecticide) by endophytic bacterium, Bacillus thuringiensis strain NIT-2, isolated from neonicotinoid-treated plant samples.

Nitenpyram (neonicotinoid insecticide) is commonly used for crop protection from pests. Currently, due to its widespread use, the nitenpyram accumulation in the environment is anticipated to be high. Hence, the removal of nitenpyram residue from the environment is essential. However, the biodegradation of nitenpyram by endophytes is still unreported. Therefore, we aimed to isolate and identify a bacterial strain capable of degrading nitenpyram. We isolated approximately 300 endophytic strains from Brassica rapa var. perviridis that had been exposed to different neonicotinoid insecticides. After 14 days of incubation, a bacterial strain, NIT-2, with nitenpyram degradation capability (approximately 65%) was found. Via 16S rRNA gene sequencing, the strain was identified as Bacillus thuringiensis. In addition, metabolites, 2-[N-(6-chloro-3-pyridylmethyl)-N-ethyl]amino-2-methyliminoacetic acid, N-(6-chloro-3-pyridilmethyl)-N-ethyl-N-methylformamidine (CPMF), and N-(6-chloro-3-pyridilmethyl)-N-ethylformamide (CPF), were identified during the degradation. Moreover, CPMF and CPF were further degraded 71% and 18%, respectively by NIT-2. Thus, B. thuringiensis strain NIT-2 is the first reported endophytic bacterium capable of degrading nitenpyram.

The Long-Term Agroecosystem Research cropland common experiment at Northern Plains.

Cropland agriculture in the northern Great Plains is challenged by variable weather, agricultural intensification, and competing use for energy development. Innovative cropland practices that address these challenges are needed to ensure regional agriculture can sustainably meet future food, fuel, and fiber demand. In response to this need, the Northern Plains Long-Term Agroecosystem Research Network site established a cropland experiment in 2019 that contrasts prevailing and alternative practices at plot and field scales over a proposed 30-year time frame. The experimental site is located on the Area IV Soil Conservation Districts Cooperative Research Farm near Mandan, ND. Cropping practices for the first 6 years of the experiment were developed with input from stakeholders and include a 3-year crop rotation of spring wheat (Triticum aestivum L.), corn (Zea mays L.), and soybean (Glycine max L.) with cover crops (alternative practice) and without (prevailing practice). The prevailing practice also involves the removal of crop residue, while a second alternative practice of perennial forages is included in the plot-scale experiment. Biophysical measurements are made at both spatial scales at frequencies aligned with approved methods for each agronomic and environmental metric. Findings from the first 6 years of the experiment will help identify tradeoffs associated with cover crop use and residue removal in dryland cropping systems. In the future, the experiment will adopt a knowledge co-production approach whereby researchers and stakeholders will work collaboratively to identify problems, implement research, and interpret results.

Targeted desialylation and cytolysis of tumour cells by fusing a sialidase to a bispecific T-cell engager.

Bispecific T-cell engagers (BiTEs) bring together tumour cells and cytotoxic T cells by binding to specific cell-surface tumour antigens and T-cell receptors, and have been clinically successful for the treatment of B-cell malignancies. Here we show that a BiTE-sialidase fusion protein enhances the susceptibility of solid tumours to BiTE-mediated cytolysis of tumour cells via targeted desialylation-that is, the removal of terminal sialic acid residues on glycans-at the BiTE-induced T-cell-tumour-cell interface. In xenograft and syngeneic mouse models of leukaemia and of melanoma and breast cancer, and compared with the parental BiTE molecules, targeted desialylation via the BiTE-sialidase fusion proteins enhanced the formation of immunological synapses, T-cell activation and T-cell-mediated tumour-cell cytolysis in the presence of the target antigen. The targeted desialylation of tumour cells may enhance the potency of therapies relying on T-cell engagers.

Dissipation, processing factors and dietary risk assessment of the bioinsecticide abamectin in herbal plants belonging to Lamiaceae family from open field to herbal tea infusion

Abamectin, the mixture of avermectin B1a and B1b, is widely used as a bioinsecticide and is an alternative to chemical pest control from insects. To our knowledge, its behaviour is not fully recognized, especially in herbs. Thus, the objective of this study was to investigate the environmental fate of abamectin in herbal plants belonging to the Lamiaceae family, its dissipation in open field studies laboratory processing treatments and dietary risk assessment. Three medicinally and culinary important species of herbs: Melissa officinalis L., Mentha × piperita L. and Salvia L. were treated with single and double dose than recommended on the label during their cultivation (BBCH 11–29). Residues were monitored using the QuEChERS method followed by the LC-MS/MS. The dissipation pattern of the sum of avermectin B1a and B1b and their persistence were observed 14 d after spraying. Abamectin decline was very rapid in plants and followed the first-order kinetics model. The half-life (t1/2) was in the range of 0.96–1.08 d (single dose) and 0.93–1.02 d (double dose). The pre-harvest intervals (decrease to the level of 0.01 mg kg−1) were 7.29–7.92 d at single and 7.99–8.64 d at double dose application. Herbal infusion preparation in previously washed and dried mint, lemon balm and sage leaves was the key processing step in the removal of abamectin residues. The reduction of initial deposits after single dose treatment was noted up to 65% (PF = 0.35–0.67) and up to 79% after double dose application (PF = 0.21–0.72) in herbal tea. Acute risk assessment of children and adults for the highest residues in EFSA PRIMo model at single and double dose expressed as hazard quotients (HQ) were <1, indicating no risk to humans via consumption of the herbal products. The data provide a better understanding of abamectin behaviour in herbal plants and can help assure herbs' safety for consumers.

Cryomilling-assisted high purity β-chitin extraction from Uroteuthis edulis pens

We report on the extraction of β-chitin from pens (or Gladius) of Uroteuthis edulis, a squid species prevalent in the Pacific coastal regions of East Asia. In particular, we employ cryogenic mechanical grinding (or cryomilling) as a pre-treatment process for the raw squid pens. We show that the cryomilling step enables an effective pulverization of the raw materials, which facilitates the removal of protein residues allowing the extraction of high-purity β-chitin with a high acetylation degree (∼97 %) and crystallinity (∼82 %). We also demonstrate that the Uroteuthis edulis extract β-chitin affords a free-standing film with excellent optical transmittance and mechanical properties.

Inhibition of neuraminidase-1 sialidase activity by interfering peptides impairs insulin receptor activity in vitro and glucose homeostasis in vivo

Neuraminidases also called sialidases are glycosidases which catalyze the removal of terminal sialic acid residues from glycoproteins, glycolipids and oligosaccharides. Mammalian Neuraminidase-1 (NEU-1) participates in regulation of cell surface receptors such as insulin receptor (IR), epithelial growth factor receptor, low density lipoprotein receptor and toll like receptor 4. At the plasma membrane, NEU-1 can be associated with the elastin-binding protein and the carboxypeptidase protective protein/cathepsin A to constitute the elastin receptor complex. In this complex, NEU-1 is essential for elastogenesis, signal transduction through this receptor and for biological effects of the elastin-derived peptides on atherosclerosis, thrombosis, insulin resistance, non-alcoholic steatohepatitis and cancers. This is why research teams are developing inhibitors targeting this sialidase. Previously, we developed interfering peptides to inhibit the dimerization and the activation of NEU-1. In this study, we investigated the effects of these peptides on IR activation in vitro and in vivo. Using cellular overexpression and endogenous expression models of NEU-1 and IR (COS-7 and HepG2 cells respectively), we have shown that interfering peptides inhibit NEU-1 dimerization and sialidase activity which results in a reduction of IR phosphorylation. These results demonstrated that NEU-1 positively regulates IR phosphorylation and activation in our conditions. In vivo, biodistribution study showed that interfering peptides are well distributed in mice. Treatment of C57Bl/6 mice during eight weeks with interfering peptides induces a hyperglycemic effect in our experimental conditions. Altogether, we report here that inhibition of NEU-1 sialidase activity by interfering peptides decreases IR activity in vitro and glucose homeostasis in vivo.

Effect of fabrication process on contact resistance and channel in graphene field effect transistors

Contact resistance, as one of the main parameters that limits the performance of graphene-based transistors, is highly dependent on the metal-graphene contact fabrication processes. These processes are investigated and the corresponding resistances are measured based on the transfer length method (TLM). In fabrication processes, when annealing is done on chemical vapor deposition (CVD)-grown graphene samples that are transferred onto SiO2/Si substrates, the adhesion of graphene to the substrate is improved, and poly methyl methacrylate (PMMA) residues are also reduced. When the metal deposition layer is first applied to the graphene, and then, the photolithography process is performed to define the electrodes and graphene sheet, the graphene-metal contact resistance is better than that in other methods due to the removal of photoresist residues. In fact, by changing the sequence of the fabrication process steps, the direct contact between photoresist and graphene surface can be prevented. Thus, the contact resistance is reduced and conductivity increases, and in this way, the performance of graphene transistor improves. The results show that the fabrication process has a noticeable effect on the transistor properties such as contact resistance, channel sheet resistance, and conductivity.‌ Here, by using the annealing process and changing the order of photolithography processes, a contact resistance of 470 Ω μm is obtained for Ni-graphene contact, which is relatively favorable.