Addition Of Sulfate Research Articles

Maximizing strength and durability in wood concrete (arbolite) via innovative additive control and consumption

AbstractA new approach for assessing the effectiveness and determining the consumption of additives to regulate the structural and mechanical characteristics of wood concrete is proposed, which allows rapid assessment in a short time and reduces the consumption of materials. The period is reduced from 28 to 1 day, and the sample sizes are reduced from 150 × 150 × 150 to 20 × 20 × 20 mm compared to those of the standard method. The results obtained are comparable using both methods within an error of up to 7%. The thermal conductivity of wood concrete with the addition of potassium sulfate was 20.8% less than that with the addition of calcium chloride. This reduction will reduce wall thickness, material consumption, and cost by 20.8%. In this regard, potassium sulfate, which does not form crystalline hydrates and makes it possible to obtain a material with lower thermal conductivity than other additives, all other things being equal, has a new advantage for wood concrete. In addition, potassium sulfate reduces the risk of corrosion of cement stone because one of the main causes of corrosion is crystalline hydrates. Reducing the risk of corrosion will increase the durability of the material.

Mechanical properties of sisal fiber-reinforced fly ash cement mortar activated by sodium sulfate

The substantial use of fly ash as cement replacement to reduce carbon emissions is identified as the primary goal, 50 % of the cement was substituted with fly ash and in order to avoid the low early stage mechanical properties of the composite, varying doses of sodium sulfate were used as an activator of fly ash. Additionally, sisal fibers were chosen to enhance the flexural strength. The results indicate that sodium sulfate significantly enhances the early stage mechanical performance of the cementitious composites and the matrix exhibits the optimal mechanical performance at 4 wt% sodium sulfate dosage (4SS). The addition of sisal fibers resulted in an enhancement of the flexural performance of the material. The collaboration between sodium sulfate and sisal fibers results in an improvement in the initial flexural performance of the material while preserving its compressive strength. The single-fiber pullout test further confirmed that adding sodium sulfate enhances the fiber-matrix interface and bonding. Microstructural investigations by XRD, TGA, MIP, and SEM-EDS revealed accelerated hydration and early formation of a large amount of ettringite due to the addition of sodium sulfate. Ettringite acts as a gel nucleation seed, promoting the formation of a dense gel structure and effectively improving the early mechanical properties of the composite. Furthermore, with curing age, sodium sulfate also effectively improves the pore structure of the matrix in the late hydration stage.

Free radical mechanisms of ammonium sulfate as intensively used industrial materials on suppressing organic pollutants

Organic free radicals are critical intermediates for the generation and inhibition of organic pollutants during industrial processes. Clarifying the free radical mechanism of pollutant inhibition is significant for their efficient control. Ammonium sulfate is intensively used in industrial materials to suppress organic pollutants. In this study, organic free radical intermediate species in metal-catalyzed reactions inhibited by ammonium sulfate were identified using continuous-wave electron paramagnetic resonance (EPR) spectroscopy, providing direct evidence for the free radical mechanisms of organic pollutants inhibition. The transverse (T2) and longitudinal (T1) relaxation time variations catalyzed by different metal catalysts in the presence of ammonium sulfate were compared using pulsed-wave EPR. Consequently, after the addition of ammonium sulfate, the observed increase in T2 suggests that ammonium sulfate leads to radical concentration reduction. A decrease in the T1 relaxation time suggests the enhanced interaction between organic radicals and metals, which is an obstacle to subsequent radical reactions. Therefore, ammonium sulfate dominantly changed the free radical intermediates species, concentrations, and their reactivity, and then inhibited the organic pollutants formations. The inhibition mechanisms of ammonium sulfate on metal-catalyzed pollutants were then proposed combining EPR analysis, X-ray characterization, and high-resolution mass spectrometry screening. As a result, (1) occupying the active sites of metal catalysis and (2) inhibiting free radical intermediates are the two main intrinsic inhibition mechanisms of ammonium sulfate. The findings provide new perspectives on the efficient inhibition of organic pollutants in industrial processes involving various metal catalysts.

Hollow-like three-dimensional structure of methyl orange-delaminated Ti3C2 MXene nanocomposite for high-performance electrochemical sensing of tryptophan.

Tryptophan(Trp) is being explored as a potential biomarker for various diseases associated with decreased tryptophan levels; however, metabolomic methods are expensive and time-consuming and require extensive sample analysis, making them urgently needed for trace detection. Toexploit the properties of Ti3C2 MXenes a rational porous methyl orange (MO)-delaminated Ti3C2 MXene was preparedvia a facile mixing process for the electrocatalytic oxidation of Trp. The hollow-like 3D structure with a more open structure and the synergistic effect of MO and conductive Ti3C2 MXene enhanced its electrochemical catalytic capability toward Trp biosensing. More importantly, MO can stabilize Ti3C2 MXene nanosheets through noncovalent π-π interactions and hydrogen bonding. Compared with covalent attachment, these non-covalent interactions preserve the electronic conductivity of the Ti3C2 MXene nanosheets. Finally, the addition of MO-derived nitrogen (N) and sulfur (S) atoms to Ti3C2 MXene enhanced the electronegativity and improved its affinity for specific molecules, resulting in high-performance electrocatalytic activity. The proposed biosensor exhibited a wide linear response in concentration ranges of 0.01-0.3 µM and 0.5-120 µM, with a low detection limit of 15 nM for tryptophan detection, and high anti-interference ability in complex media of human urine and egg white matrices. The exceptional abilities of the MO/Ti3C2 nanocatalyst make it a promising electrode material for the detection of important biomolecules.

Appropriate sulfur fertilization in contaminated soil enhanced the cadmium uptake by hyperaccumulator Sedum alfredii Hance

The biogeochemical processes of sulfur and heavy metals in the environment are closely related to each other. We investigated the influence of sulfur addition on hyperaccumulator Sedum alfredii Hance growth, cadmium (Cd) accumulation, soil Cd bioavailability, soil bacterial communities and plant transcriptome responses. The results showed that an appropriate rate of sulfur addition (1.0 or 2.5 g/kg) enhanced the growth of Sedum alfredii Hance plants as well as their accumulation of Cd. A high rate of sulfur addition (5.0 or 10.0 g/kg) causes toxicity to Sedum alfredii Hance plants. The application of an appropriate amount of sulfur to the soil increased the abundance of sulfur-oxidizing bacteria such as Sulfuriferula and Thiobacillus; acid-fast bacillus such as Alicyclobacillus; and cadmium-tolerant bacteria such as Bacillus and Rhodanobacter. This led to a decrease in pH and an increase in bioavailable Cd in the soil. RNA sequencing revealed that the addition of sulfur to soils led to the up regulation of most of the differentially expressed genes (DEGs) involved in “photosynthesis” and “photosynthesis, light reaction” in Sedum alfredii Hance leaves. Moreover, the “plant hormone signal transduction” pathway was significantly enriched with sulfur addition. Sulfur assimilation in Sedum alfredii Hance plants may promote photosynthesis and hormone synthesis, leading to Cd tolerance in these plants. Our study revealed that sulfur fertilization enhanced the efficiency of Cd phytoremediation in Sedum alfredii Hance plants.

A method for synthesis of waterborne polyurethane using an eco-friendly surfactant

In general, waterborne polyurethane molecular chains containing hydrophilic groups usually require extended drying times to achieve sufficient film formation, thereby increasing energy consumption. The preparation of high-solid content waterborne polyurethane has attracted significant attention in both scientific research and industrial applications. The primary challenges associated with increasing the solid content of waterborne polyurethane are poor fluidity and inadequate storage stability. In this study, two surfactants, sodium lauryl sulfate and polyethylene glycol, were incorporated into the emulsification process of waterborne polyurethane to achieve a solid content of more than 50 %. The effect of different addition levels ranging from 1 to 5 wt% on viscosity, storage stability, physical and mechanical properties, thermal properties, and surface morphology of dried WPU films was further investigated. Waterborne polyurethane dispersion without surfactants solidified within a month, whereas those with surfactants remained stable for up to four months. Furthermore, the addition of sodium lauryl sulfate and polyethylene glycol significantly reduced the viscosity of waterborne polyurethane to 6–80 P and 3–17 P, respectively. Compared to SDS, PEG offers several advantages, including non-toxicity, biocompatibility, and solubility in various solvents. The addition of 1 wt% polyethylene glycol resulted in a stable waterborne polyurethane dispersion, achieving a solids content above 50 % with a viscosity of 17 P. This fundamental study establishes a pathway for preparing high solid content WPU using environmentally friendly surfactants.

(Invited) Sulfur Addition Reaction Onto Carbon Nanotubes

The surface chemistry of carbon nanotubes is of interest for material’s processing and modification of their electronic and optical properties. Here, we present a new sulfur addition reaction to single-wall and multi-wall carbon nanotubes. Depending on the reaction conditions, we find strong evidence of addition reaction, which produces covalent bonding between sulfur atoms and the nanotube surfaces. Raman, TEM, and photoemission results are consistent with the formation of covalent S-C bonds on the sidewalls. DFT calculations also support a formation of sulfur-carbon bonding and predict electronic and vibrational states that are in good agreement with the experimental results. Based on a comparison between theory and experiments, we propose a stable episulfide (GS) grafting, which consists of of a sulfur atom bridging two carbon atoms repeated over the nanotube surface.

Enhancement of nitrogen removal in constructed wetlands through boron mud and elemental sulfur addition: Regulation of sulfur and oxygen cycling

Constructed wetlands (CWs) utilizing elemental sulfur (S0) as an electron donor are effective for nitrate (NO3–-N) removal from low C/N wastewater. However, the limited bioavailability of chemical S0 (chem-S0) due to low water solubility and inadequate mass transfer impedes complete denitrification. In this study, boron mud waste and S0 (S0&BM) were processed and combined to convert chem-S0 to biological S0 (bio-S0) in CWs. The employment of S0&BM improved NO3–-N and total nitrogen (TN) removal rates by 15.36 % and 10.55 % compared to S0 alone. The 15N isotope tracing experiment unveiled the pathways of N2O production and demonstrated that S0&BM facilitated full denitrification, resulting in a higher percentage of nitrogen being degraded in a non-polluting form (54.70 %). Releasing trace amounts of boron and magnesium in S0&BM mitigated the excessive acidification caused by the sulfur autotrophic process and promoted biofilm formation, thereby pronouncing vertical oxygen fluctuations. Meanwhile, oxygen vacancies generated in the S0&BM promoted the closed-loop sulfur cycle, starting from the oxidation of chem-S0 to sulfate (SO42-), the important process of SO42--reducing bacteria using partial organic compounds as electron donors to reduce SO42- to sulfide (S2-) was realized, and finally the S2- was oxidized to bio-S0 with better properties. S0&BM enriched functional microbial communities in the biofilm related to nitrogen and sulfur transformation. Functional gene analysis showed an increase in the narG, nirS, norB, and nosZ genes supporting denitrification. The dsrA and sqr genes responsible for the sulfur cycle exhibited the highest abundance. This realization allowed for the utilization of waste materials for treatment, enhancing the energy efficiency of carbon reduction and pollution reduction in CWs.

Aluminum-induced oxidative stress promotes changes in the structure of the gut microbiota and liver deficiency

As a low-toxicity metal, aluminum has garnered increasing attention in relation to its impact on the human body; however, the specific mechanism of action remains unclear. To bridge this knowledge gap and facilitate practical applications, this study took 8-week-old ICR mice as the research object to study the effects of dietary addition of aluminum potassium sulfate on intestinal flora structure and liver. As the concentration of aluminum increased, it inhibited mice weight growth rate and significantly altered the composition of white blood cells in their bloodstream. Histological examination revealed liver inflammation through HE staining sections. The oxidative stress markers MDA increased, GSH-PX and CAT decreased significantly. And liver function index MAO increased, TC and ALP decreased first and then increased. Moreover, there was a significant increase in pro-inflammatory factor TNF-α content. Further 16S rRNA sequencing analysis demonstrated substantial changes in both composition and structure of mouse intestinal microbiota induced by aluminum exposure; microbial phenotype prediction indicated that aluminum-induced oxidative stress promoted an increase in abundance of oxidation-resistant microbial types. Alterations in gut flora structure also influenced the liver via the gut-liver axis. These findings lay a foundation for further research on the regulation and interaction of aluminum on intestinal flora.

Synergistic enhancement of bifunctional activity and stability of seawater electrolysis by in situ etching and concentration strategies

An effective way to lessen the scarcity of freshwater resources is recognized as seawater electrolysis. Significant importance is attached to developing bifunctional catalysts appropriate for seawater electrolysis in industrial settings. In situ, etching and electrodeposition on nickel foam substrates were used in this study to create SNiFe@NF catalysts. Experiments demonstrated a positive link between catalytic activity and the KOH concentration in the electrolyte. The addition of sulfur not only increases catalytic activity but also increases resistance to Cl-. This is because sulfur has a low electronegativity, which helps to produce hydroxyl oxides by modulating the electronic structure between Ni and Fe. As predicted, at a current density of 100 mA cm−2, the SNiFe@NF catalyst demonstrated extraordinarily low overpotentials of 90 mV (HER) and 261 mV (OER). Moreover, after undergoing stability tests, the catalyst surface developed a SO42- layer that created a Cl- barrier, providing the basis for excellent stability. Interestingly, the electrolyzer used using SNiFe@NF catalysts also showed an outstanding 1.48 V at 100 mA cm−2 overall water splitting capacity. Furthermore, after 20 hours of continuous operation, no attenuation was seen in the catalysts' performance under high-temperature and high-alkalinity industrial settings. The results of this work provide a simple and efficient method for producing highly active bifunctional corrosion-resistant catalysts, which have significant ramifications for the development of the hydrogen economy.

Lignocellulose-based gel polymer electrolyte composited by a special additive of elemental sulfur with outstanding performances in lithium–sulfur batteries

Gel polymer electrolyte (GPE) based on polymer matrix of lignocellulose and gelatinized potato starch is prepared, and elemental sulfur is introduced as an additive for the first time. The polymer matrix has shown excellent performances including liquid electrolyte uptake, tensile strength and thermal stability. The ionic conductivity and electrochemical stability window of the corresponding GPE are improved with the introduction of the elemental sulfur. Furthermore, the addition of elemental sulfur can be reduced into short-chain Li2S and Li2S2 on the surface of lithium anode to further elevate the capacity of battery. Meanwhile, the short-chain Li2S and Li2S2 in the solid electrolyte interphase (SEI) film on the surface of lithium metal can improve SEI’s mechanical properties and the interface compatibility between GPE and lithium metal. The multi-component synergistic effect of GPE provides the battery with superior cycle stability and excellent electrochemical performances. Bio-based GPE will exhibit a promising and alternative way for the practical application of lithium–sulfur batteries.

In-situ inhibition mechanism of SO3 formation over MoS2 modified V2O5/TiO2 catalyst within selective catalytic reduction process

The utilization of commercial vanadium-titanium based catalysts (V2O5/TiO2) within the selective catalytic reduction (SCR) process is a prominent contributor to the emergence of sulfur trioxide (SO3) in coal-fired boiler environments. The direct modification of vanadium-titanium based catalysts has big potential to be an efficacious strategy for in-situ inhibiting SO3 formation. This research evaluates the effectiveness of MoS2 modified V2O5/TiO2 catalyst on SO2 oxidation under diverse conditions, using controlled condensation for SO3 collection. The results showed that V2O5-MoS2/TiO2 catalysts outperformed conventional V2O5/TiO2 catalysts in inhibiting the oxidation from SO2 to SO3 between 200 and 400 °C, with optimal performance at 350 °C. No significant effect was observed on the catalytic oxidation of SO2 when the O2 concentration was lower than that of SO2, whereas the introduction of appropriate quantities of NO promoted the generation of SO3. The excessive inclusion of NH3 nearly doubled the SO3 generation rate, increasing it from 0.284 % to 0.434 %. The NO and NH3 mixture markedly reduced SO3 generation to 0.085 % at a 62 mL/min mixture concentration, just 30 % of the rate without the mixture. Following the reaction of SO2 and O2, the reacted catalyst exhibited reduced pore volume, enhanced thermochemical stability, and lower susceptibility to SO2 catalytic oxidation. The addition of low-valence sulfur improves catalyst reducibility, reduces V5+–OH reactions in various atmospheres, and decreases the formation of sulphate and gaseous SO3. The Mo-S-Mo group also effectively prevents the formation of HSO4− intermediates. Additionally, MoS2 reacts with SO3 via a reduction reaction, significantly lowering the SO3 levels. Finally, in diverse atmospheric conditions, the catalysts maintained their V5+ content and catalytic efficiency, thus improving SCR performance stability.

Low-carbon emitting Fe-cycle recovery of battery-grade FePO4 from biogas slurry for Li-battery application

Under the background of carbon peaking and carbon neutrality in China, anaerobic digestion of sludge to produce methane was an important way to recover biomass energy. But plenty of as-generated biogas slurry (BS) with high P concentration was valuable and difficult to dispose. Here, this work proposed a low-carbon emitting Fe-cycle strategy to recover battery-grade FePO4 from BS. At pH=1.0, the P-leaching rate of Fe-sludge (42.93 ± 1.49 mg g−1) generated by polymerized ferrous sulfate (an inorganic polymer coagulant) addition into BS was 93.46 ± 3.56% and high-purity FePO4 (99.0%) could further be obtained by Fe3+ supplement and pH adjustment (pH=2.0). The contents of all elements in recovered FePO4 product fully complied with the battery grade of national industry standard of China (HG/T 4701-2021). After battery-grade FePO4 precipitate separation, recovery solution (RS) with remaining Fe3+ was reutilized to remove 88.05 ± 1.77% of P when mixed with BS wit RS/BS ratio of 2:1, thus achieving a Fe cycle utilization. Meanwhile, the recovery cost of 5.42 $/kg P and CO2 emissions of 80.83 kg/kg P were lower than those of current FePO4 industrial production (14.60 $/kg P and 110.60 kg/kg P). Finally, the LiFePO4/C cathode material based on recovered FePO4 from BS exhibited stable discharge specific capacity of 84.6–100.2 mAh/g during 100 charge–discharge cycles. In general, this study successfully manifested the feasibility of novel Fe-cycle battery-grade FePO4 recovery strategy from wastewater, paving a viable low-carbon emitting pathway for future Li-battery manufacture industry.

Substantially enhanced reaction of steel slag binder stimulated by the addition of sodium sulfate and thermal treatment

An industrial by-product of steel slag has a huge potential as an alternative binder and new supplementary cementitious material (SCM). In both pure steel slag and composite systems, the amount of sulfate can be a critical factor to control early-age performance. This study aims to improve the hydration of steel slag stimulated by using a small amount of Na2SO4. The results showed that 1 % Na2SO4 enhanced both C2(A,F) and C2S hydration, leading to improved strength and denser microstructures with the formation of ettringite, AFm, and siliceous hydrogarnet. Initial thermal treatment at 40 °C with 3 % Na2SO4 provided a fast development of compressive strength at 3 days over 15 MPa. Meanwhile, an excessive amount of alkali supplied by Na2SO4 affects the relative stability between SO4-rich AFm and ettringite and has a detrimental effect on mechanical performance. The result implies that Na2SO4 content should be precisely controlled when used as a stimulator in a composite system with steel slag.

Magnesium Sulfate Versus Lidocaine as an Adjunct for Renal Colic in the Emergency Department: A Randomized, Double-Blind Controlled Trial

ObjectiveWe wished to determine whether the addition of magnesium sulfate (MgSO4) or lidocaine to diclofenac could improve the analgesic efficacy in emergency department (ED) patients with acute renal colic. MethodsIn this prospective, double-blinded, randomized controlled trial of patients aged 18-65 years with suspected acute renal colic, we randomized them to receive 75 mg intramuscular (IM) diclofenac and then either intravenous (IV) MgSO4, lidocaine, or saline control. Subjects reported their pain using a Numerical Rating Scale (NRS) before drug administration and then 5, 10, 20, 30, 60, and 90 minutes afterwards. Our primary outcome was the proportion of participants achieving at least a 50% reduction in NRS 30 min after drug administration. ResultsWe enrolled 280 patients in each group. A 50% or greater reduction in NRS at 30 minutes occurred in 227 (81.7%) patients in MgSO4 group, 204 (72.9%) in lidocaine group, and 201 (71.8%) in control group, with significant differences between MgSO4 and lidocaine (8.8%; 95% CI [1.89-15.7]; p=0.013) and between MgSO4 and control (9.9%; 95% CI [2.95-16.84]; p=0.004). Despite this, differences between all groups at every time point were below the accepted 1.3 threshold for clinical importance. There were no observed differences between groups in the frequency of rescue analgesics and return visits to the ED for renal colic. There were more adverse events, although minor, in the MgSO4 group. ConclusionAdding intravenous MgSO4, but not lidocaine, to IM diclofenac offered superior pain relief, but at levels below accepted thresholds for clinical importance.

A study of tiamulin removal by nanosecond pulsed gas–liquid discharge underwater

AbstractIn this study, gas–liquid discharge plasma excited by nanosecond pulsed voltage is used to efficiently remove tiamulin (TIA) from water. The discharge produces a large number of reactive species (H2O2, OH radicals, NO3−, etc.) that can attack the TIA molecules. The effects of peak pulse voltage, initial TIA concentration, gas composition, and the addition of ferrous sulfate and persulfate on TIA removal were mainly investigated. The results showed that the oxygen plasma could approach 100% removal within 30 min of treatment time. The addition of the catalyst increased the TIA removal efficiency by approximately 15% during the 10‐min discharge treatment time. The toxicity of 12 intermediates was analyzed and the degradation mechanism of TIA was investigated.

Can Hyaluronic Acid Combined with Chondroitin Sulfate in Viscosupplementation of Knee Osteoarthritis Improve Pain Symptoms and Mobility?

The objective of the present study was to assess the effect of intra-articular Hyaluronic acid (HA) and Chondroitin sulfate (CS) supplementation (Hialurom® Hondro (HH)) on pain symptoms and joint mobility. In total, 60 mg/mL sodium hyaluronate and 90 mg/mL CS were administered to 21 patients (17 females and 4 males) respecting the in-force requirements, excluding patients with some specific comorbidities. In addition to the clinical study (where the pain intensity (severity) and joint mobility were assessed), rheological characterization was conducted evaluating the following parameters: elastic modulus (G'), loss modulus (G″) oscillatory frequency (fc) at 0.5 Hz and 2.5 Hz, crossover frequency (fc), relaxation time (λ) where it was noticed that the addition of chondroitin sulfate (CS) to sodium hyaluronate (SH) significantly enhances and improves the viscoelastic properties, particularly at higher shear frequencies. A significant decrease in pain intensity felt by the subjects was found, from 7.48 (according to Wong-Baker scale)-pain close to 8 (the patient is unable to perform most activities), to more reduced values of 5.86-at 6 weeks after injection, 4.81-at 3 months after injection, and 5.24-at 6 months after injection, improvements in symptoms was fast and durable. Data related to the evolution of joint mobility show that at 6 weeks after injection, the mobility of joints increased by 17.8% and at 6 months by 35.61%. No serious adverse events were reported with undesired effects so that they would impose additional measures. Better resistance to enzymatic degradation and free radicals could be expected from the synergic combination of sodium hyaluronate and chondroitin sodium sulfate, this having a special importance for the patients, granting them the ability to perform more ample movements and reducing dependency on attendants, thus increasing quality of life.

Clinical effects of perineural dexmedetomidine or magnesium sulphate as adjuvants to ropivacaine in dogs undergoing tibial plateau leveling osteotomy

The study aimed to compare the quality of perioperative analgesia, the motor block duration, and the effects on main cardiovascular parameters of dexmedetomidine (1 μg/kg/nerve block) or magnesium sulphate (2 mg/kg/nerve block) as adjuvants to 0.3% ropivacaine for sciatic and saphenous nerves block in dogs undergoing tibial plateau leveling osteotomy (TPLO). Dogs randomly received perineural dexmedetomidine-ropivacaine (D group), magnesium sulphate-ropivacaine (M group), or ropivacaine (C group). Fentanyl was administered in case of intraoperative nociception. Postoperative pain was assessed using the Short Form-Glasgow Composite Measure Pain Scale (SF-GCMPS) and VAS scale. The duration of motor blockade and intra- and postoperative cardiovascular parameters were also recorded. Group M required significantly more fentanyl than D group (p = 0.04). Group M had a significantly higher SF-GCMPS score than group C at 4 (p = 0.002) and 5 h after extubation (p = 0.01), and a significantly higher VAS score than group D at 3 h after extubation (p = 0.03), and at 4 h if compared to group C (p = 0.009). No significant differences regarding the duration of motor blockade were detected between groups (p = 0.07). The heart rate was significantly lower in group D than in M and C groups intraoperatively and during the first 1.5 h post extubation. The addition of dexmedetomidine or magnesium sulphate as adjuvants to perineural ropivacaine did not improve the quality of perioperative analgesia and did not prolong the motor blockade in dogs undergoing sciatic and saphenous nerves block for TPLO surgery.

Comparative Study between Rocuronium And Magnesium Sulfate as Adjutants to Regional Anesthesia for Ophthalmic Surgeries using Peribulbar Block

Abstract Background Peribulbar anesthesia is frequently used in cataract surgeries. Compared to retrobulbar anesthesia, this approach is associated with less significant consequences. However, it has the disadvantages of a slower onset of orbital akinesia and the frequent requirement for block supplementation. Aim of the Work To evaluate the effect of addition of magnesium sulfate and rocuronium to standard local anesthetics mixture on the time of onset of globe and lid akinesia and corneal anesthesia for peribulbar block in ophthalmic surgeries. Patients and Methods This Prospective Double-blinded Randomized Study was carried out in the ophthalmic surgery unit, Ain Shams university hospital from January 2019 to April 2020. After institutional Ethical Board approval and obtaining written informed patients’ consents, 75 patients from both sexes, ASA physical status I-III, aged 40-80 years and having an Axial globe length less than or equals 26 mm scheduled for cataract surgery under peribulbar block were included in the study. Results Our study found statistically significant more rapid onset of action (mean time to start surgery) in rocuronium group (7.00±1.22) than control group and magnesium sulfate group (9.00±1.47 and 9.00±1.15) respectively, (p < 0.001); Moreover, no statistically significant difference was reported between control group and magnesium sulfate group. In addition, no significant difference was reported regarding duration of surgery between groups Conclusion Adding Rocuronium to local anesthetic mixture in peribulbar block during cataract surgery enhances ocular akinesia and corneal anesthesia and reduces the need for supplementary injections with no side effects and that was significantly better than Magnesium sulfate in term of rapid onset and time needed to achieve adequate condition to begin surgery. However, adding Magnesium sulfate showing good results regarding akinesia, corneal anesthesia and need for supplementary injections but it did not significantly fasten the onset of block and hence the time to start surgery.

Engineering Escherichia coli for efficient glutathione production

Glutathione is a tripeptide of excellent value in the pharmaceutical, food, and cosmetic industries that is currently produced during yeast fermentation. In this case, glutathione accumulates intracellularly, which hinders high production. Here, we engineered Escherichia coli for the efficient production of glutathione. A total of 4.3 g/L glutathione was produced by overexpressing gshA and gshB, which encode cysteine glutamate ligase and glutathione synthetase, respectively, and most of the glutathione was excreted into the culture medium. Further improvements were achieved by inhibiting degradation (Δggt and ΔpepT); deleting gor (Δgor), which encodes glutathione oxide reductase; attenuating glutathione uptake (ΔyliABCD); and enhancing cysteine production (PompF-cysE). The engineered strain KG06 produced 19.6 g/L glutathione after 48 h of fed-batch fermentation with continuous addition of ammonium sulfate as the sulfur source. We also found that continuous feeding of glycine had a crucial role for effective glutathione production. The results of metabolic flux and metabolomic analyses suggested that the conversion of O-acetylserine to cysteine is the rate-limiting step in glutathione production by KG06. The use of sodium thiosulfate largely overcame this limitation, increasing the glutathione titer to 22.0 g/L, which is, to our knowledge, the highest titer reported to date in the literature. This study is the first report of glutathione fermentation without adding cysteine in E. coli. Our findings provide a great potential of E. coli fermentation process for the industrial production of glutathione.