Min Washing Research Articles

Optimisation of Operational Parameters of a Spiral Classifier Using Design of Experiment (DOE)

Abstract
 Classifying Mn Ore to improve upon the grade and the properties has become a crucial activity for the Mn industry since it increases the market value of the ore. Ghana Manganese Company (GMC) has renovated their oxide washing plant by integrating it with a spiral classifier to make a batch system operating process. Particle size of <3.35mm (Mn grade of 43-47%) obtained from the primary section of the plant served as feed to the classifier and with the plant condition (i.e. at 60 min washing time, 30 rev/min speed of spirals and feed tonnage of 6 t), Mn grade of 49% was achieved. This paper focused on the optimisation of some selected operational parameters of the classifier to obtain a Mn grade >50% using Design of Experiment (DOE). Series of test works were designed using the DOE for the classifier using the constraints of washing time (30-90 min), speed of spirals (20-40 rev/min) and feed tonnage (6-9 t). The outcome of the test work after simulation showed that all the selected parameters had a great influence on Mn grade. The spiral speed and feed tonnage correlated negatively to the Mn grade with washing time correlating positively. Operating the spiral classifier at a feed rate, spiral speed and washing time of 6 t, 25 rev/min, and 30 min, respectively, yielded Mn grade of 53%. A Confirmatory test using the established conditions gave a Mn grade of 53%, which is a 4% increment in the previous Mn grade which was 47%. The outcome of the studies is the new established operational conditions which is adhered to by the plant, producing a manganese concentrate grade ranging between 52-54%.
 
 Keywords: Design of Experiment (DOE), Spiral Classifier, Grade, Manganese

Improvement of washing properties of liquid laundry detergents by modification with N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate sulfobetaine

Detergency of commercial liquid detergents before and after modification with SB3C16 (5%, m/m) sulfobetaine (N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate) was examined using colorimetric analysis based on a CIELab system. The EMPA 101 standard cotton fabric soiled with carbon black and olive oil was used in washing tests under the following experimental conditions: the concentration of liquid laundry detergents 1.25–50 g/L, 30 min washing cycle, water hardness 5.35 mval/L, 40℃, 200 rpm. Results of physicochemical analysis of color, form, odor, pH, viscosity, density and content of anionic surfactants in detergents, as well as construction parameters of tested cotton fabrics, showed compliance with the requirements of standards and manufacturers’ declarations. The studies revealed that increasing the concentration of laundry detergent solutions caused a gradual increase in foaming power and detergency. Modification with SB3C16 positively improved washing ability and the maximum values were achieved at 23.7% (m-L1, 50 g/L) and 37% (m-L2, 40–45 g/L), respectively. Detergency efficiency was improved by 6.86% (m-L1) and 10.72% (m-L2) on average. EMPA 101 fabrics before and after washing were subjected to microscopic observations, which showed no serious damage to the fibers, but only slight loosening of individual fibers. In summary, the results clearly indicate that SB3C16 sulfobetaine favorably improves washing performance and can be successfully used in liquid laundry detergents due to its good surface properties.

Wax-printed well pads and colorimetric LAMP detection of ApxIA toxin gene

Actinobacillus pleuropneumoniae (A. pleuropneumoniae) produces hemolytic cytotoxins, ApxI, ApxII, ApxIII, and ApxIV, causing a huge loss to the swine industry. We developed the PadLysis protocol for extracting genomic DNA (gDNA) for the LAMP—LeucoCrystal Violet (LCV) colorimetric detection. A paper-based well pad for gDNA extraction was fabricated using a wax printing method. Furthermore, the LAMP amplicons were detected in situ with colorimetric dye, LCV. Wax-printed well pads (WPWPs) have hydrophobic wax barriers by printing a well pattern that allows the establishment of simple and equipment-free PadLysis protocol consisting of the three steps: (1) 2 min lysis, (2) 2 min washing, and (3) 1 min drying. This proposed platform allowed direct LAMP amplification for A. pleuropneumoniae field isolates. We optimized LCV chemical components to enable the accurate LAMP signal readouts. The overall assay takes up to 45 min including 5 min PadLysis, 40 min LAMP amplification, and LCV signal observation with the naked eye. Our WPWPs–LAMP–LCV approach can be used as a rapid screening tool for A. pleuropneumoniae pleuropneumonia (APP) caused by ApxIA toxin in future outbreak areas.

EFFECT OF ELECTROLYZED REDUCING WATER WITH VARIOUS CONCENTRATION ON CARBENDAZIM FUNGICIDE REMOVAL IN CHERRY TOMATO

The effect of electrolyzed reducing water (ER) on a degradation of carbendazim residues degradation of cherry tomato (Solanum lycopersicum L. var. cerasiforme) was investigated. Electrolyzed water was generated by electrolysis from 5% NaCl solution. The cherry tomato samples were washed in ER water at different concentrations (100, 250, 500 and 1000 mg/L) and in distilled water (control). The standard carbendazim solution (5 mg/L) was treated with the previous concentrations of ER. Reduction of residual carbendazim was determined by high performance liquid chromatography (HPLC) while liquid chromatography-quadrupole-timeof-flight mass spectrometer (Agilent, LC-6545 Q-TOF/MS) was used to determine the concentration of anions as major degradation products. It was found that all concentration of ER water significantly reduced carbendazim solution, compared to control. The ER water at 250 mg/L could effectively remove carbendazim residues from cherry tomato, most of the degradation occurred within 30 min. Residue of carbendazim on cherry tomato were reduced by 60.36%, 80.49%, 67.32%, and 64.68% after 30 min washing in ER 100 mg/L, 250 mg/L, 500 mg/L, and 1000 mg/L, respectively.

Solvent-based washing as a treatment alternative for onshore petroleum drill cuttings in Thailand

In Thailand, onshore drill cuttings (DC) contaminated with total petroleum hydrocarbon (TPH) are currently transported off-site for incineration, causing high transportation cost and potential leakage to the environment. To address the issues, we develop solvent-based washing as a greener alternative for onshore DC remediation, focusing on solvent selection, washing process optimization, and solvent recovery. The results showed that ethyl lactate (EL) was the best green solvent for DC washing, compared to water, ethylene glycol, and ethyl acetate. Based on response surface methodology assisted with central composite design, the maximum TPH removal of 87.1% was achieved from 4 mL g−1 liquid-to-solid ratio, 14 min washing time, and 80 rpm stirring speed, and the TPH removal rate by EL fitted well with the second-order reaction (R2 = 0.9774). Furthermore, the spent EL was successfully recycled by simple and low-energy adsorption using granular activated carbon (GAC). With the sufficient GAC dosage, TPH could be completely removed from the spent EL without impairing the original EL properties. Moreover, the recycled EL exhibited its successful reuse in the subsequent DC washing process. These findings suggest that solvent washing accompanied with solvent recovery by adsorption could be a novel and greener remedial scheme for onshore DC management.

Effects of shiitakes household processing on the residues of six pesticides

The consumption of pesticide residues contaminated shiitakes resulted in important health issues in humans. This study evaluated the effects of classic household processing on six different pesticides used in shiitake culture, detailed in pesticide residue behavior and processing factors (PFs). Our results demonstrated that stir-frying or frying reduced the residue levels of all six pesticides. Washing and boiling significantly decreased the concentrations of carbendazim, thiabendazole, and procymidone. After each household processing step, the calculated PFs of all pesticides were less than one except for the 1–10 min boiling of bifenthrin, λ-cyhalothrin, and β-cyfluthrin. The most effective combination of processing to reduce the residue levels of carbendazim, thiabendazole, and procymidone in fresh shiitakes was washing for 10 min and then boiling for another 10 min. The best combination of processing to reduce the residue levels of bifenthrin, λ-cyhalothrin, and β-cyfluthrin was washing for 10 min and then frying for 60 s. Practical applications This study suggests that the residue concentrations of all six pesticides were decreased in shiitakes during household processing. Considering the results of pesticides’ residuals and processing factors, the typical household processing, including washing, boiling, frying, and rehydrating, were recommended to reduce the pesticide residuals. The combination to reduce carbendazim, thiabendazole, and procymidone residues in fresh shiitakes was 10 min washing and then another 10 min boiling. The suggested combination for bifenthrin, λ-cyhalothrin, and β-cyfluthrin was 10 min washing and then a 60 s frying.

Soil washing in combination with electrochemical advanced oxidation for the remediation of synthetic soil heavily contaminated with diesel

Sequential soil washing and electrochemical advanced oxidation processes (EAOPs) were applied for the remediation of synthetic soil contaminated with diesel. The surfactant Tween 80 was used to enhance the extraction of diesel from synthetic soil, and diesel extraction efficiency was improved with the increase of Tween 80 concentration. Under conditions of 180 min washing time, 10 g synthetic soil with 100 mL surfactant solution and two times of soil washing, about 75.2%, 80.0% and 87.9% of diesel was extracted from synthetic soil with 5.0, 7.5 and 10.0 g L−1 Tween 80. The degradation of diesel in soil washing effluent was carried out by two EAOPs, electro-oxidation (EO) and electro-Fenton (EF) using boron-doped diamond (BDD) anode and carbon felt cathode cell. After 360 min EO treatment, 72.7–83.0% of diesel was removed from the effluent after soil washing with 5.0–10.0 g L−1 Tween 80 while higher removal efficiencies (77.7–87.2%) were attained with EF process. Parallel factor analysis (PARAFAC) of excitation emission matrix (EEM) fluorescence spectroscopy was conducted to analysis the transformation of fluorescent components in diesel during the treatment by two EAOPs.

Improved garment longevity and reduced microfibre release are important sustainability benefits of laundering in colder and quicker washing machine cycles

The global impact of laundering clothing is significant, with high levels of water, energy use, and pollution associated with this consumer care process. In this research, the impacts of washing temperature and washing time on garment colour loss (dye fading), colour transfer (dye staining), and microfibre release were evaluated using retail consumer clothing. Significantly greater colour loss and greater colour transfer were observed for a 40 °C, 85 min wash cycle compared to a cold-quick (25 °C; 30 min) cycle. Desorbing dyes were found to mainly be reactive dyes. From fundamental kinetic studies, it was observed that significant increases in both rate of dye desorption and total dye desorption occurred when increasing from 20 °C to 40 °C, but the difference in dye release between 40 °C and 60 °C was not as significant; the same kinetic trends were observed for dye transfer. Microfibre release was significantly greater for the 40 °C, 85 min cycle in comparison with the cold-quick cycle, and this effect continued with further washes. These results mean that reducing time and temperature in laundry could have a significant impact in terms of extended garment longevity and reduced dye and microfibre liberation into the environment, in addition to energy savings.

Inactivation of Salmonella in cherry tomato stem scars and quality preservation by pulsed light treatment and antimicrobial wash

The objective of this study was to evaluate the effectiveness of pulsed light (PL) treatment, a novel antimicrobial (LAPEN) wash and combinations thereof in inactivating Salmonella on stem scars of cherry tomato. The treatment effects on background microbiota and sensory quality was also investigated while in storage for 21 days at 10 °C. Three serotypes of Salmonella enterica were chosen to prepare inoculum for the current investigation for their link with tomato and produce outbreaks. Stem scars of tomato were spot inoculated before being treated with PL (1–63 J/cm2), LAPEN sanitizer (2 min) or combinations of PL with LAPEN Sanitizer. Significant inactivation was observed at low doses of PL. A 30 s treatment equivalent to a dose of 31.5 J/cm2, was found optimal. The optimal dose provided 2.3 log reduction of Salmonella while a 2 min wash in LAPEN sanitizer provided 2.1 log CFU/g reduction on stem scars. Two possible sequences of PL and LAPEN combinations were explored. For PL-LAPEN combination, inoculated tomatoes were initially exposed to optimum PL dose (31.5 J/cm2) and then washed 2 min in LAPEN sanitizer whereas for LAPEN-PL combination, tomatoes were initially immersed 2 min in LAPEN prior to PL treatment. Treatment of PL-LAPEN demonstrated a strong synergistic inactivation as no Salmonella survivor were detectable after treatment indicating greater than 5 log reduction, whereas LAPEN-PL combination revealed a compound inactivation providing 4.5 logs reduction of the pathogen. The PL-LAPEN treatment not only reduced native microbiota of tomato but also hindered their growth while in storage for three weeks. The firmness and visual appearance quality of tomato were not significantly influenced due to PL-LAPEN combination treatment until day 21, when the texture of treated tomato was significantly influenced. Overall, the results reveal that PL-LAPEN combination treatment can be implemented as a novel approach to enhance microbial safety and quality of cherry tomato.

Thermal Behavior During Exercise Alleviates Thermal Discomfort Despite Exacerbating Increases in Core Temperature

PurposeIncreases in metabolic heat production during exercise stimulate perceptions of thermal discomfort as core and skin temperatures, and skin wettedness increase. Thermal discomfort is the precursor to thermal behavior. Employing thermal behavior during exercise may reduce thermal discomfort by attenuating the rise in core temperature. However, this remains unknown. We tested the hypothesis that thermal behavior attenuates the rise in core temperature and alleviates thermal discomfort during exercise.MethodsTwelve healthy subjects (24 ± 3 y, 6 females) performed two trials in which they completed 60 min of recumbent cycling exercise at a fixed rate of metabolic heat production (217 ± 28 W/m2) in a 27 ± 0°C, 48 ± 6% relative humidity environment. In both trials subjects wore a water perfused suit top. In the control trial, 34 ± 0°C water circulated through the top during the trial (CON). The experimental trial allowed for thermal behavior (BEH) where subjects were instructed to maintain their upper body thermally comfortable throughout. In BEH, subjects thermally behaved by pressing a button to receive cool water (2 ± 1°C) through the water perfused suit top for 2 min, which was followed by a 1 min wash out period. Mean skin (10 site) and core (telemetry pill) temperatures, mean skin wettedness (8 site), skin blood flow (forearm, laser Doppler), and local sweat rate (ventilated capsule) were measured continually. Local sweat rate was measured under (on mid‐axillary line) and outside (on anterior thigh, n=7) of the water perfused suit top. Whole body thermal comfort was recorded every 10 min. Water perfused suit top temperature provided an index of thermal behavior. Data are presented as mean ± SD as the absolute change from the values acquired pre‐exercise.ResultsMetabolic heat production was not different between trials (P=0.44). The increase in core temperature was greater in BEH vs. CON at 50 and 60 min (both by +0.1 ± 0.3°C, P<0.01). Mean skin temperature was reduced in BEH vs. CON from 20 min (by −0.5 ± 0.7°C, P<0.01) onwards (P<0.01). Mean skin wettedness was greater in BEH vs. CON from 30 min (by +0.01 ± 0.03 a.u., P<0.01) onwards (P<0.01). Water perfused suit top temperature was reduced in BEH vs. CON from 10 min (by −5.6 ± 7.0°C, P<0.01) onwards (P<0.01). Mid‐axillary sweat rate was attenuated in BEH vs. CON from 10 min (by −0.1 ± 0.12 g/cm2/min) onwards (P<0.01), and thigh sweat rate was attenuated at min 20 (by: −0.1 ± 0.2 g/cm2/min) and 60 (by −0.2 ± 0.2 g/cm2/min). Forearm skin blood flow was not different between BEH and CON at any time (P=0.20). Increases in whole body thermal discomfort were attenuated in BEH vs. CON within the first 10 min (by −0.4 ± 0.4 a.u., P=0.04) onwards (P<0.01).ConclusionsEmploying thermal behavior that reduces mean skin temperature during exercise alleviates thermal discomfort despite exacerbating the rise in core temperature and skin wettedness. Reductions in sweat rate may contribute to the greater rise in core temperature when employing thermal behavior. These findings may question the role of skin wettedness in stimulating thermal behavior during exercise.Support or Funding InformationSupported by lululemon athletica inc.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effects of pulsed light and sanitizer wash combination on inactivation of Escherichia coli O157:H7, microbial loads and apparent quality of spinach leaves

The purpose of this study was to investigate the efficacy of pulsed light (PL), a new formula of sanitizer (HEN) consisting of hydrogen peroxide, EDTA and Nisin, as well as synergy of PL and HEN sanitizer (PL-HEN) wash in inactivating E. coli O157:H7 on spinach. The treatment effect on microbial loads and apparent quality during 13 days storage at 4 °C was also determined. A bacterial cocktail containing three strains of E. coli O157:H7 was used as inoculum based on their association with produce-related outbreaks. Spinach leaves were spot inoculated on surface before treating with PL (1–63J/cm2), HEN sanitizer wash (2 min) or their combinations. PL inactivation was influenced significantly at low doses. Treatment dose of 15.75 J/cm2, equivalent to 15 s intense PL treatment, was found optimal above which adverse quality effect was evident. The optimal PL dose resulted 2.7 log CFU/g reduction of E. coli O157:H7 while a rapid 2 min wash in sanitizer formulation HEN, provided comparatively low, 1.8 log CFU/g, reduction of the pathogen. Two different sequences of PL and HEN treatment combinations were tested. In PL-HEN treatment, inoculated leaves were first treated at optimal PL dose (15.75 J/cm2) followed by 2 min immersion in HEN whereas in HEN-PL treatment, leaves were first washed in HEN before PL exposure. HEN-PL treatment indicated a compound inactivation activity (4.6 logs reduction) while PL-HEN treatment indicated a strong synergistic inactivation as E. coli cells were not detectable after treatment indicating >5 log reduction. The PL-HEN treatment not only significantly reduced spoilage microbial populations on spinach but also slowed their growth during storage. Furthermore, the visual and firmness quality of spinach were not significantly affected by the PL-HEN treatment. Overall, our results demonstrate that integrated PL-HEN technology can be used to enhance microbial safety of spinach.

A Facile Approach for Preparing Ag Functionalized Nonwoven Polypropylene Membrane to Improve Its Electrical Conductivity and Electromagnetic Shielding Performance.

The commonly used preparation methods of polypropylene functionalization require special equipment to be put into use or take a long time, which limits its application. Therefore, a simple and economical method for preparing silver functionalized nonwoven polypropylene membrane was studied herein. Triethanolamine was first coated on the surface of the polypropylene, and then Ag was deposited on the surface of polypropylene using a continuous reduction reaction of triethanolamine and silver ions. Surface morphology, crystal structure, and surface chemistry during the preparation of Ag functionalized nonwoven polypropylene were investigated. The electrical conductivity, electromagnetic shielding properties, and washing durability of the treated nonwoven polypropylene were also studied. It was found that Ag was uniformly deposited on the surface of the nonwoven polypropylene, and the coating reaction did not change the chemical structure of the polypropylene. The crystallinity and thermal stability of polypropylene were improved after silver coated polypropylene. The washing experiment results showed that the weight gain rate of the treated nonwoven relative to the untreated sample after the 90 min washing ranged from 6.72% to 9.64%. The resistance test results showed that the maximum surface resistivity of Ag coated nonwoven polypropylene was about 1.95 × 105 Ω, which was 64,615 times lower than the original. In addition, the results showed that the maximum electromagnetic shielding effectiveness of the Ag coated nonwoven polypropylene was about 71.6 dB, showing a very good electromagnetic shielding effect.

Flow Injection-Traveling-Wave Ion Mobility-Mass Spectrometry for Prostate-Cancer Metabolomics.

Flow injection-traveling-wave ion mobility-mass spectrometry (FI-TWIM-MS) was applied to the nontargeted metabolic profiling of serum extracts from 61 prostate-cancer (PCa) patients and 42 controls with an analysis speed of 6 min per sample, including a 3 min wash run. Comprehensive data mining of the mobility-mass domain was used to discriminate species with various charge states and filter matrix salt-cluster ions. Specific criteria were developed to ensure correct grouping of adducts, in-source fragments, and impurities in the data set. Endogenous metabolites were identified with high confidence using FI-TWIM-MS/MS and collision-cross-section (CCS) matching with chemical standards or CCS databases. PCa patient samples were distinguished from control samples with good accuracies (88.3-89.3%), sensitivities (88.5-90.2%), and specificity (88.1%) using supervised multivariate classification methods. Although largely underutilized in metabolomics studies, FI-TWIM-MS proved advantageous in terms of analysis speed, separation of ions in complex mixtures, improved signal-to-noise ratio, and reduction of spectral congestion. Results from this study showcase the potential of FI-TWIM-MS as a high-throughput metabolic-profiling tool for large-scale metabolomics studies.

Uticaj litijum sulfata na Šenonovu entropiju hromatina kod limfocita

Introduction: Lithium affects numerous signal pathways in cells, which may ultimately lead to either increased or decreased gene expression in cell nuclei. However, effects of lithium on higher level of gene organization in the nuclei, like chromatin, is still poorly understood. Aim: To investigate the effects of lithium on chromatin organization in the nuclei of lymphocytes by investigating changes in Shannon entropy of chromatin in these cells. Material and Methods: Peripheral blood was treated with lithium sulphate until lithium concentrations of 1mmol/l, 2 mmol/l i 3 mmol/l was not reached. The smears were fixed with methanol and stained by Felgen method for DNK visualization. Cells in the smear were treated with hydrochloric acid for 120 min. Schiff reagent was used for staining for 120 min and smear washing was done with 6 ml of 10% of water solution of natrium metabisulfite. After staining, digital micrographs for each of the most representative sample of 30 lymphocytic chromatin structures were made. Shannon entropy was calculated by converting micrograph in the format of textual numerical string. Lymphocyte chromatin was also analyzed by textural method analysis. Results: Treatment with 1 mmol/l of lithium sulphate did not lead to a statistically significant increase in entropy values (p > 0.05). However, in samples where the concentration of lithium was 2 i 3 mmol/l, respectively, there was a statistically significant increase in entropy (p < 0.05). Also, a statistically significant and dose-dependent linear trend of an increase of chromatin entropy was detected in samples (p < 0.05). After lithium sulphate treatment, neither the mean value of angular second moment lymphocyte chromatin in control sample nor the inverse moment of the difference of treated lymphocytes changed (p > 0.05). Conclusion: Lithium sulphate in peripheral blood lymphocytes causes dose-dependent increase in Shannon chromatin entropy, which is not followed with similar changes in a textural chromatin parameters.

Efficient Degradation of Malathion in the Presence of Detergents Using an Engineered Organophosphorus Hydrolase Highly Expressed by Pichia pastoris without Methanol Induction.

The biodegradation of pesticides by organophosphorus hydrolases (OPHs) requires an efficient enzyme production technology in industry. Herein, a Pichia pastoris strain was constructed for the extracellular expression of PoOPHM9, an engineered malathion-degrading enzyme. After optimization, the maximum titer and yield of fermentation reached 50.8 kU/L and 4.1 gprotein/L after 3 days, with the highest space-time yield (STY) reported so far, 640 U L-1 h-1. PoOPHM9 displayed its high activity and stability in the presence of 0.1% (w/w) plant-derived detergent. Only 0.04 mg/mL enzyme could completely remove 0.15 mM malathion in aqueous solution within 20 min. Furthermore, 12 μmol malathion on apples and cucumbers surfaces was completely removed by 0.05 mg/mL PoOPHM9 in tap water after 35 min washing. The efficient production of the highly active PoOPHM9 has cleared a major barrier to biodegradation of pesticide residues in food industry.

Effects of submicron ammonium sulfate particles on the growth and yield of komatsuna (Brassica rapa L. var. perviridis)

The aim of this study was to determine the effects of submicron ammonium sulfate (AS) particles on komatsuna (Brassica rapa L. cv. Hakkei) plants. First, we optimized a leaf-washing method to measure the amount of AS particles deposited on the leaf surface of the plants. Then, we used this method to determine the retention time of particles deposited on the leaf surface of the plants. We also investigated the effects of AS particles on the growth and yield of the plants. Almost all the AS particles deposited on the leaf surface were removed within 1 min washing time with ultrapure water, and ion leaching from the leaf was relatively slow but continuous during the leaf-washing procedure. On the basis of these results, we determined that 1 min was a suitable washing time to remove most of the AS particles while minimizing the influence of ion leaching from the leaf. The amount of particulate SO42− deposited on the leaf surface decreased over time, probably because AS particles deposited on the leaf surface deliquesced, allowing ions such as SO42− in the deliquescence solution to be absorbed into the leaf. The plants were grown and exposed to AS particles for 16 days in naturally lit phytotrons. The daily mean increase in the concentration of SO42− in PM2.5 by the exposure to AS particles was 22.5 μg m−3 in the phytotrons. The growth and yield of the plants were significantly reduced by the exposure to AS particles. The exposure to AS particles did not affect the leaf concentrations of nitrogen and chlorophyll, but significantly reduced stomatal conductance. Therefore, stomatal closure is one of the reasons for the AS particle-induced reductions in the growth and yield of komatsuna plants.

Intermittent Hypoxia during Gestation Disrupts Respiratory Rhythm and Neuroplasticity in Newborn Rat Brainstem‐spinal cord Preparations In Vitro

Pregnant women with sleep‐disordered breathing experience intermittent hypoxia, especially during late pregnancy. To test whether intermittent hypoxia exposures during pregnancy (G‐IH; gestational intermittent hypoxia) alter breathing in newborn rats, pregnant rats were exposed to intermittent hypoxia (2 min 10.5% oxygen / 2 min normoxia for 8 h) from gestational day 10 to 21 (exposures completed prior to birth). Newborn rats (P0–P3) were anesthetized and their brainstem‐spinal cords isolated under in vitro conditions. Spontaneous respiratory motor bursts were recorded on cervical spinal roots (C4–C5). G‐IH preparations from P0–P1 rats had a lower baseline burst frequency (8.2 +/− 0.6 bursts/min; n=10) compared to normoxic controls (11.0 +/− 0.3 bursts/min; n=21). After 90 min, burst frequency decreased with time nearly 2× times greater in G‐IH preparations compared to controls. In most G‐IH preparations, there were frequent “pauses” in the rhythm, which resembled spontaneous apneas. With respect to respiratory neuroplasticity, dihydroxyflavone (DHF) application (5 micromolar, 9 min; TrkB receptor agonist) induced long‐lasting 19% increase in respiratory motor burst amplitude in control preparations (n=5) after 90 min. However, only 2/4 G‐IH preparations expressed a DHF‐dependent increase in motor burst amplitude. Also, episodic substance‐P application (100 nanomolar, 3 min on / 7 min wash ×3) induced a long‐lasting (60‐min) increase in respiratory burst frequency in control preparations. However, there was no substance‐P induced frequency plasticity in any G‐IH preparations (n=4). These data suggest that gestational intermittent hypoxia disrupts respiratory rhythm generation and reduces the capacity for expressing respiratory neuroplasticity in newborn rats.Support or Funding InformationNIH Grant: NS085226

Neurosteroids reverse tonic inhibitory deficits in Fragile X syndrome mouse model

Fragile X syndrome (FXS) is the most common form of inherited intellectual disability. In addition, there is increased incidence of anxiety, sleep irregularities, and seizure activity. The underlying cause of FXS is a loss of the fragile X mental retardation protein (FMRP) which has been shown to participate in the biosynthesis of δ subunits. Studies from both FXS patients and animal models have revealed reduced expression levels of GABAAR α4 and δ subunits with a reduced efficacy of tonic inhibition. Neurosteroids (NS) are known allosteric modulators of GABAAR channel function but recent studies from our laboratory have revealed that NS also exert persistent effects on the efficacy of tonic inhibition by increasing the PKC‐mediated phosphorylation of the α4 subunit which increases the membrane expression and boosts tonic inhibition. We have used a combination of biochemical and electrophysiological methods to assess alterations in GABAergic signaling in the hippocampus of FMRP knock‐out mouse (Fmr1 KO), a widely validated model of the human syndrome.Our preliminary studies demonstrate that Fmr1 KO mice at p21 have a decrease in phosphorylation of S443 in the α4 subunit compared to WT and an increase in the phosphorylation of β3 subunits at the S408/409 site compared to WT. We have previously showed that phosphorylation of these residues changes the trafficking of the subunits so the changes observed in Fmr1 KO mice would predictably have consequences for trafficking of these essential inhibitory subunits. However, at p48–72 Fmr1 KO mice did not exhibit any deficits in GABAAR expression levels or phosphorylation demonstrating a critical developmental deficit in GABAAR expression. We noted that there was a significant decrease in tonic inhibition in dentate gyrus granule cells in p21 Fmr1 KO mice compared to WT. A 10 min exposure to 1μM THDOC followed by 330 min wash induced a &gt;3 fold increase in tonic current in Fmr1 KO animals which was prevented with PKC inhibition. Using a perforated multi‐electrode array we have observed in horizontal cortical‐hippocampal slices seizure like events (SLE) propagating through the dentate gyrus and into the CA3 and CA1 regions of the hippocampus of Fmr1 KO mice but in WT mice SLEs did not propagate through the dentate gyrus. We predict the increase neuronal excitability seen in Fmr1 KO mice is due to the deficits in tonic inhibition.We have observed that THDOC treatment effectively reversed tonic current deficits in Fmr1 KO mice. Future studies will focus on ameliorating behavioral deficits in Fmr1 KO mice with synthetic neuroactive steroids that display improved pharmacokinetic properties.Support or Funding InformationThis work was supported by grants from the National Institutes of Health (NIH)‐National Institute of Alcoholism and Alcohol Abuse grant AA017938 (P.A.D), NIH‐National Institute of Mental Health grant, MH097446, and DOD, AR140209 (PAD &amp; SJM), NIH‐National Institute of Neurological Disorders and Stroke grant NS051195, NS056359, NS081735, NS080064, NS087662 (SJM), the Simons Foundation #206026 (S.J.M.).

Effects of natural antimicrobials on prevention and reduction of bacterial cross-contamination during the washing of ready-to-eat fresh-cut lettuce.

Microbiological safety of the fresh-cut produce may not be guaranteed if the quality of wash water is not maintained. The use of natural antimicrobials as alternative to chlorine may offer interesting possibilities for disinfecting wash water. Antimicrobial properties of allyl- and benzyl-isothiocyanates, respectively, and chitosan against Salmonella spp. were evaluated by standard plate count. Minimal inhibitory concentration values were observed for benzyl-isothiocyanate and chitosan, corresponding to 50 and 1000 mgl-1, respectively. A 5 min washing of 25 g fresh-cut lettuce was performed. Transfer of Salmonella from the water to the produce was observed. Benzyl-isothiocyanate addition of 75 mgl-1 before starting the washing process gave rise to a complete removal of total bacteria and Salmonella in the wash water after 24 h before starting the second cycle. Antimicrobial benzyl-isothiocyanate effects have been demonstrated to persist after 48 h.

Endogenous and synthetic neuroactive steroids evoke sustained increases in the efficacy of GABAergic inhibition via a protein kinase C-dependent mechanism

The neuroactive steroid (NAS) tetrahydrodeoxycorticosterone (THDOC) increases protein kinase C (PKC) mediated phosphorylation of extrasynaptic GABAA receptor (GABAAR) subunits leading to increased surface expression of α4/β3 subunit-containing extrasynaptic GABAARs, leading to a sustained increase in GABAAR tonic current density. Whether other naturally occurring and synthetic NASs share both an allosteric and metabotropic action on GABAARs is unknown. Here, we examine the allosteric and metabotropic properties of allopregnanolone (ALLO), and synthetic NASs SGE-516 and ganaxolone. ALLO, SGE-516, and ganaxolone all allosterically enhanced prototypical synaptic and extrasynaptic recombinant GABAARs. In dentate gyrus granule cells (DGGCs) all three NASs, when applied acutely, allosterically enhanced tonic and phasic GABAergic currents. In separate experiments, slices were exposed to NASs for 15 min, and then transferred to a steroid naïve recording chamber followed by ≥ 30 min wash before tonic currents were measured. A sustained increase in tonic current was observed following exposure to ALLO, or SGE-516 and was prevented by inhibiting PKC with GF 109203X. No increase in tonic current was observed with exposure to ganaxolone. In agreement with the observations of an increased tonic current, the NASs ALLO and SGE-516 increased the phosphorylation and surface expression of the β3 subunit-containing GABAARs. Our studies demonstrate that neuroactive steroids have differential abilities to induce sustained increases in the efficacy of tonic inhibition by promoting GABAAR phosphorylation and membrane trafficking dependent on PKC activity.