Influence of surfactant molecular features on tetracycline transport in saturated porous media of varied surface heterogeneities

This study aims to understand how surfactants affect the mobility of tetracycline (TC), an antibiotic, through different aquifer media. Two anionic and cationic surfactants, sodium dodecylbenzene sulfonate (SDBS) and cetyltrimethyl ammonium bromide (CTAB), were used to study their influence on TC mobility through clean sand and humic acid (HA)-coated sand. HA coating inhibits TC mobility due to its strong interaction with TC. Both surfactants promoted TC mobility at pH 7.0 due to competitive deposition, steric effect, and increased hydrophilicity of TC. CTAB had a more substantial effect than SDBS, related to the surfactants' molecular properties. Each surfactant's promotion effects were greater in HA-coated sand than in quartz sand due to differences in surfactant retention. CTAB inhibited TC transport at pH 9.0 due to its significant hydrophobicity effect. Furthermore, in the presence of Ca2+, SDBS enhanced TC transport by forming deposited SDBS-Ca2+-TC complexes. On the other hand, CTAB increased TC mobility due to its inhibition of cation bridging between TC and porous media. The findings highlight surfactants' crucial role in influencing the environmental behaviors of tetracycline antibiotics in varied aquifers.

Transport of sulfanilamide in saturated porous media under different solution chemistry conditions: role of physicochemical characteristics of soils

Identification of the transport of sulfonamide antibiotics in soils facilitates a better understanding of the environmental fate and behaviors of these ubiquitous contaminants. In this study, the mobility properties of sulfanilamide (SNM, a typical sulfonamide antibiotic) through saturated soils with different physicochemical characteristics were investigated. The results showed that the physicochemical characteristics controlled SNM mobility. Generally, the mobility of SNM was positively correlated with CEC values and soil organic matter content, which was mainly related to the interactions between the organic matter in soils and SNM molecules via π-π stacking, H-bonding, ligand exchange, and hydrophobic interaction. Furthermore, higher clay mineral content and lower sand content were beneficial for restraining SNM transport in the soils. Unlike Na+, Cu2+ ions could act as bridging agents between the soil grains and SNM molecules, contributing to the relatively weak transport of SNM. Furthermore, the trend of SNM mobility in different soil columns was unaffected by solution pH (5.0-9.0). Meanwhile, for a given soil, the SNM mobility was promoted as the solution pH values increased, which was caused by the enhanced electrostatic repulsion between SNM- species and soil particles as well as the declined hydrophobic interaction between SNM and soil organic matter. The obtained results provide helpful information for the contribution of soil physicochemical characteristics to the transport behaviors of sulfonamide antibiotics in soil-water systems.

Low-molecular-weight organic acids-mediated transport of neonicotinoid pesticides through saturated soil porous media: Combined effects of the molecular structures of organic acids and the chemical properties of contaminants

Empirical information about the transport properties of neonicotinoid pesticides through the soil as affected by the ubiquitous low molecular weight organic acids (LMWOAs) is lacking. Herein, the impacts of three LMWOAs with different molecular structures, including citric acid, acetic acid, and malic acid, on the mobility characteristics of two typical neonicotinoid pesticides (Dinotefuran (DTF) and Nitenpyram (NTP)) were explored. Interestingly, under acidic conditions, different mechanisms were involved in transporting DTF and NTP by adding exogenous LMWOAs. Concretely, acetic acid and malic acid inhibited DTF transport, ascribed to the enhanced electrostatic attraction between DTF and porous media and the additional binding sites provided by the deposited LMWOAs. However, citric acid slightly enhanced DTF mobility due to the fact that the inhibitory effect was weakened by the steric hindrance effect induced by the deposited citric acid with a large molecular size. In comparison, all three LMWOAs promoted NTP transport at pH 5.0. Because the interaction between NTP with soil organic matter (e.g., via π-π stacking interaction) was masked by the LMWOAs coating on soil surfaces. Nevertheless, LMWOAs could promote the mobility of both neonicotinoid pesticides at pH 7.0 due to the steric hindrance effect caused by the deposited organic acids and the competitive retention between LMWOAs and pesticides for effective surface deposition sites of soil particles. Furthermore, the extent of the promotion effects of LMWOAs generally followed the order of citric acid > malic acid > acetic acid. This pattern was highly related to their molecular structures (e.g., number and type of functional groups and molecular size). Additionally, when the background solutions contained Ca2+, the bridging effect of cations also contributed to the transport-enhancement effects of LMWOAs. The findings provide valuable information about the mobility behaviors of neonicotinoid pesticides co-existing with LMWOAs in soil-water systems.

Low-molecular-weight aromatic acids mediated the adsorption of Cd2+ onto biochars: effects and mechanisms

Low-molecular-weight aromatic acids (LWMAAs), a ubiquitous organic substance in natural systems, are important in controlling the environmental fate of potentially toxic metals. However, little is known about the effects of LWMAAs on the interactions between biochars and potentially toxic metals. Herein, the influences of three aromatic acids, including benzoic acid (BA), p-hydroxy benzoic acid (PHBA), and syringic acid (SA), on the adsorption of Cd2+ onto biochars generated at three different pyrolysis temperatures under acidic and neutral conditions were examined. Generally, the adsorption ability of biochars for Cd2+ improved with the increase of pyrolysis temperature, which was ascribed to the increased inorganic element contents (e.g., P, S, and Si) and aromaticity, increasing the complexation between mineral anions and metal ions, and the enhanced cation-π interaction. Interestingly, aromatic acids considerably inhibited the adsorption of Cd2+ onto biochars, which was mainly ascribed to multi-mechanisms, including competition of LWMAA molecules and metal ions for adsorption sites, the pore blocking effect, the weakened interaction between mineral anions and Cd2+ induced by the adsorbed aromatic acids, and the formation of water-soluble metal-aromatic acid complexes. Furthermore, the inhibitory effects of LWMAAs on Cd2+ adsorption intensively depended on the aromatic acid type and followed the order of SA > PHBA > BA. This trend was related to the differences in the physicochemical features (e.g., the octanol/water partition coefficient (log Kow) and molecular size) of diverse LMWAAs. The results of this study demonstrate that the effects of coexisting LMWAAs should not be ignored when biochars are applied in soil remediation and wastewater treatment.

Mobility of antipyretic drugs with different molecular structures in saturated soil porous media

In the post-COVID-19 era, extensive quantities of antipyretic drugs are being haphazardly released from households into the environment, which may pose potential risks to ecological systems and human health. Identification of the mobility behaviors of these compounds in the subsurface environment is crucial to understand the environmental fate of these common contaminants. The mobility properties of three broad-spectrum antipyretic drugs, including ibuprofen (IBF), indometacin (IMC), and acetaminophen (APAP), in porous soil media, were investigated in this study. The results showed that the mobility of the three drugs (the background electrolyte was Na+) through the soil column followed the order of APAP > IBF > IMC. The difference in the physicochemical characteristics of various antipyretic drugs (e.g., the molecular structure and hydrophobicity) could explain this trend. Unlike Na+, Ca2+ ions tended to serve as bridging agents by linking the soil grains and antipyretic molecules, leading to the relatively weak mobility behaviors of antipyretic drugs. Furthermore, for a given antipyretic drug, the antipyretic mobility was promoted when the background solution pH values were raised from 5.0 to 9.0. The phenomenon stemmed from the improved electrostatic repulsion between the dissociated species of antipyretic molecules and soil grains, as well as the weakened hydrophobic interactions between antipyretic drugs and soil organic matter. Furthermore, a two-site non-equilibrium transport model was used to estimate the mobility of antipyretic drugs. The results obtained from this work provide vital information illustrating the transport and retention of various antipyretic drugs in aquifers.

Geometric experience sculpts the development and dynamics of hippocampal sequential cell assemblies

Euclidean space is the fabric of the world we live in. Whether and how geometric experience shapes our spatial-temporal representations of the world remained unknown. We deprived rats of experience with crucial features of Euclidean geometry by rearing them inside translucent spheres, and compared activity of large hippocampal neuronal ensembles during navigation and sleep with that of cuboid cage-reared controls. Sphere-rearing from birth permitted emergence of accurate neuronal ensemble spatial codes and preconfigured and plastic time-compressed neuronal sequences. However, sphere-rearing led to diminished individual place cell tuning, similar neuronal mapping of different track ends/corners, and impaired neuronal pattern separation and plasticity of multiple linear track experiences, partly driven by reduced preconfigured network repertoires. Subsequent experience with multiple linear environments over four days largely reversed these effects, substantiating the role of geometric experience on hippocampal neural development. Thus, early-life experience with Euclidean geometry enriches the hippocampal repertoire of preconfigured neuronal patterns selected toward unique representation and discrimination of multiple linear environments.

Biosurfactant-affected mobility of oxytetracycline and its variations with surface chemical heterogeneity in saturated porous media

Herein, the influences of rhamnolipid (a typical biosurfactant) on oxytetracycline (OTC) transport in the porous media and their variations with the surface heterogeneities of the media (uncoated sand, goethite (Goe)-, and humic acid (HA)-coated sands) were explored. Compared to uncoated sand, goethite and HA coatings suppressed OTC mobility by increasing deposition sites. Interestingly, rhamnolipid-affected OTC transport strongly depended on the chemical heterogeneities of aquifers and biosurfactant concentrations. Concretely, adding rhamnolipid (1-3 mg/L) inhibited OTC mobility through sand columns because of the bridging effect of biosurfactant between sand and OTC. Unexpectedly, rhamnolipid of 10 mg/L did not further improve the inhibition of OTC transport owing to the fact that the deposition capacity of rhamnolipid reached its maximum. OTC mobility in Goe-coated sand columns was inhibited by 1 mg/L rhamnolipid. However, the inhibitory effect decreased with the increasing rhamnolipid concentration (3 mg/L) and exhibited a promoted effect at 10 mg/L rhamnolipid. This surprising observation was that the increased rhamnolipid molecules gradually occupied the favorable deposition sites (i.e., the positively charged sites). In comparison, rhamnolipid facilitated OTC transport in the HA-coated sand column. The promotion effects positively correlated with rhamnolipid concentrations because of the high electrostatic repulsion and deposition site competition induced by the deposited rhamnolipid. Another interesting phenomenon was that rhamnolipid's enhanced or inhibitory effects on OTC transport declined with the increasing solution pH because of the decreased rhamnolipid deposition on porous media surfaces. These findings benefit our understanding of the environmental behaviors of antibiotics in complex soil-water systems containing biosurfactants.

Transport of dissolved organic matters derived from biomass-pyrogenic smoke (SDOMs) and their effects on mobility of heavy metal ions in saturated porous media

Biomass-pyrogenic smoke-derived dissolved organic matter (SDOMs) percolating into the underground environment profoundly impacts the transport and fate of environmental pollutants in groundwater systems. Herein, SDOMs were produced by pyrolyzing wheat straw at 300-900 °C to explore their transport properties and effects on Cu²⁺ mobility in quartz sand porous media. The results indicated that SDOMs exhibited high mobility in saturated sand. Meanwhile, the mobility of SDOMs was enhanced at a higher pyrolysis temperature due to the decrease in their molecular sizes and the declined H-bonding interactions between SDOM molecules and sand grains. Furthermore, the transport of SDOMs was elevated as pH values were raised from 5.0 to 9.0, which resulted from the strengthened electrostatic repulsion between SDOMs and quartz sand particles. More importantly, SDOMs could facilitate Cu²⁺ transport in the quartz sand, which stemmed from forming soluble Cu-SDOM complexes. Intriguingly, the promotional function of SDOMs for the mobility of Cu²⁺ was strongly dependent on the pyrolysis temperature. Generally, SDOMs generated at higher temperatures exhibited superior effects. The phenomenon was mainly due to the differences in the Cu-binding capacities of various SDOMs (e.g., cation-π attractive interactions). Our findings highlight that the high-mobility SDOM can considerably affect heavy metal ions' environmental fate and transport.

Adsorption of fluoroquinolone antibiotics onto ferrihydrite under different anionic surfactants and solution pH

To date, little information is available regarding the impacts of the widespread anionic surfactants on the adsorption behaviors of antibiotics onto typical iron oxides. Herein, we have investigated the effects of two typical surfactants (sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS)) on the adsorption of two widely used antibiotics (i.e., levofloxacin (LEV) and ciprofloxacin (CIP)) onto ferrihydrite. Results of kinetic experiments showed that the adsorption of antibiotics was well fitted by the pseudo-second-order kinetic models, indicating that the adsorption process might be controlled by chemisorption. The affinity of ferrihydrite toward CIP was greater than that toward LEV, which was ascribed to the higher hydrophobicity of CIP than LEV. Both surfactants enhanced antibiotic adsorption owing to SDS or SDBS molecules as bridge agents between ferrihydrite particles and antibiotics. Interestingly, the extent of the enhanced effects of surfactants on antibiotic adsorption declined as the background solution pH increased from 5.0 to 9.0, which was mainly due to the weaker hydrophobic interactions between antibiotics and the adsorbed surfactants on the iron oxide surfaces as well as the greater electrostatic repulsion between the anionic species of antibiotics and the negatively charged ferrihydrite particles at higher pH. Together, these findings emphasize the importance of widespread surfactants for illustrating the interactions between fluoroquinolone antibiotics and iron oxide minerals in the natural environment.

Transport of oxytetracycline through saturated porous media: role of surface chemical heterogeneity

The current state of knowledge on the transport behaviors of oxytetracycline (OTC, a typical tetracycline antibiotic) in porous media with heterogeneous chemical surfaces is inadequate. In this work, the mobility properties of OTC through saturated porous media with different chemical heterogeneities (i.e., quartz sand, montmorillonite (MMT)-, humic acid (HA)-, and goethite (Goe)-coated sands) were investigated. In comparison with the mobility of OTC in the quartz sand, HA and goethite coatings inhibited the mobility of OTC, whereas montmorillonite coating enhanced OTC mobility. HA coating inhibited the transport of OTC that stemmed from the strong interactions between HA and OTC via complexation, π-π stacking, hydrogen bonding, and hydrophobic interaction. The positively charged iron oxide coating on Goe-coated sand provided favorable sites for OTC deposition through complexation and electrostatic attraction. The enhanced transport of OTC through MMT-coated sand was mainly due to the strong electrostatic repulsion between the anionic OTC species (i.e., OTC^-) and negatively charged porous media. Solution pH (5.0-9.0) posed a negligible effect on the trend of OTC mobility in different porous media. Furthermore, Ca²⁺ inhibited the transport of OTC mobility through various porous media via cation-bridging. The findings of this work contribute significantly to our understanding of the influence of aquifer surface chemical heterogeneities on OTC mobility behaviors in the subsurface environment.

Hematochemical profile of Cholistani cattle being reared in the Cholistan desert of Pakistan under pastoralism

ABSTRACT The objective of the present study was to assess and create normal reference intervals for hematochemical profile of Cholistani cattle (n=360) being reared under pastoralism. The comparisons have been made with earlier published data on Bos indicus and taurus cattle breeds. The general health status of animals was ascertained through a thorough anamnesis from the livestock owners and clinical signs. However, theileriosis, in specific, was ruled out through blood smear examination. The animals were assigned in groups according to age: young (n=190; ≤12 months) and adult (n=170; >12 months up till 7 years); and gender: male (n=182) and female (n=178) cattle. The mean (±SE), median, range and reference intervals (25th to 95th percentile) for hematochemical profile were determined through descriptive statistics and differences between various groups were analyzed through Mann Whitney U test. The findings of this study may serve as reference hematochemical values for Cholistani cattle in specific and humped zebu cattle in general for assessing any physiological, pathological, or metabolic alterations.

Effect of a Self-directed and Supervised Pulmonary Rehabilitation Approach on Cough and Sputum Expectoration in Chronic Obstructive Pulmonary Disease

Background. Chronic obstructive pulmonary disease (COPD) is a multifactorial, progressive chronic lung disease. COPD was rated as the third largest cause of death by the World Health Organization (WHO) in 2016. Cough and sputum are present in about 60% of COPD patients. For persons with COPD who are unable to attend the standard centre-based program, home-based pulmonary rehabilitation offers a cost-effective option. The aim. To compare the effects of supervised and self-directed pulmonary rehabilitation on cough and sputum expectoration in patients with chronic obstructive pulmonary disease. Methods. Forty COPD-diagnosed subjects with ages between 40 to 60 years were recruited for this randomized clinical trial. The participants were randomly distributed into self-managed (n=18) and supervised (n=19) groups. Data was collected using a 6-minute walk test, the Leicester Cough Questionnaire and a cough and sputum assessment questionnaire at baseline after 6 weeks post treatment. Results. There was a significant difference found between self-managed and supervised groups for six-minute walk test with P value to be P > 0.005. While analysing LCQ, overall no significant difference was observed demonstrating between two groups with P > 0.05; besides, physical factors showed a significant difference during the pre-session which showed P = 0.004. No significant difference was found while analysing values from Cough and sputum assessment questionnaire with P > 0.05 Conclusion. Supervised exercise program and self-managed group show equal improvement in COPD patients. Self-management exercise should be encouraged for active involvement of patient during the treatment and to promote self-preventive behavior. Keywords: sputum, cough, self-management, pulmonary rehabilitation.

Insight into the effect of phosphate on ferrihydrite colloid-mediated transport of tetracycline in saturated porous media

Colloid-mediated contaminant mobility is absolutely critical for the environmental behavior of contaminants such as antibiotics in water resources. In this study, the influences of phosphate (a commonly inorganic ligand in the environment) on the ferrihydrite colloid-mediated transport of tetracycline (TC, a typical antibiotic) in porous media were investigated. In the absence of colloids, phosphate promoted TC mobility due to the competitive deposition of phosphate and TC on the sand surface as well as the electrostatic repulsion. Interestingly, ferrihydrite colloids could inhibit TC transport; however, the inhibitory effect of the colloids was weakened by the addition of phosphate. This phenomenon stemmed from colloid-associated TC mobility, the increased electrostatic repulsion induced by adsorbed phosphate, and deposition site competition effect. Another interesting finding was that the impacts of phosphate on the colloid-mediated mobility of TC were pH-dependent. That is, phosphate exhibited a weaker effect on the inhibitory role of ferrihydrite colloids in TC mobility at pH 5.0 than that at pH 7.0; specially, ferrihydrite colloids acted as possible carriers of TC and facilitated antibiotic transport at pH 9.0. The observations were ascribed to different influences of phosphate on the binding affinity of ferrihydrite toward TC and the mobility of free TC under different pH conditions. Therefore, the findings of this study provide useful information about the fate and co-transport of antibiotics and natural mineral colloids in the presence of inorganic ligands in the aquatic environment.

Mobility of water-soluble aerosol organic matters (WSAOMs) and their effects on soil colloid-mediated transport of heavy metal ions in saturated porous media

Water-soluble aerosol organic matters (WSAOMs) produced by biomass pyrolysis/burning can penetrate subsurface environment, and are anticipated to have a profound effect on the fate of contaminants in aquatic ecosystems. Herein, WSAOMs derived from corn straw (CS-WSAOMs) and pinewood sawdust (PW-WSAOMs) pyrolysis at 300-900 °C were utilized to investigate their mobility characteristics and impacts on the transport of heavy metal ions (i.e., Cd²⁺) in saturated quartz sand with or without soil colloids. This study clearly demonstrated that WSAOMs in subsurface systems exhibited high mobility, which increased as WSAOMs molecular sizes decreased and hydrogen-bond interactions between WSAOMs and sand grains declined. WSAOMs significantly improved heavy metal (i.e., Cd²⁺) and soil colloid-mediated Cd²⁺ mobility in the porous media, which stemmed from the increased binding affinities of colloids toward metal ions and the high mobility of WSAOMs. Interestingly, in terms of the mobility and colloid-facilitated transport of Cd²⁺, WSAOMs from higher pyrolysis temperatures exhibited enhanced effects; meanwhile, the PW-WSAOMs demonstrated stronger effects than the CS-WSAOMs. The trends were mainly attributed to the differences in the metal-binding affinities (e.g., cation-π interactions) and transport abilities of WSAOMs, as well as diverse Cd²⁺ adsorption capacities of colloids induced by various WSAOMs.

Surfactants-mediated the enhanced mobility of tetracycline in saturated porous media and its variation with aqueous chemistry

Knowledge of the mobility of tetracycline (TC) antibiotics in porous media is critical to understand their potential environmental influences. The transport characteristics of TC in sand columns with three different surfactants, including Tween 80, sodium dodecylbenzene sulfonate (SDBS), and didodecyldimethylammonium bromide (DDAB) under various conditions were investigated in this study. Results demonstrated that all surfactants enhanced TC transport under neutral conditions (10 mM NaCl at pH 7.0). The observation was attributed mostly to deposition site competition, higher electrostatic repulsion between TC molecules and sand grains, steric hindrance, and the increase of TC hydrophilicity. Furthermore, the order of the transport-enhancement effects was generally observed as follows: DDAB > SDBS > Tween 80. The trend was controlled by the variation in the physicochemical properties of surfactants. It was noticed that the presence of Cu²⁺ (a model divalent cation) in the background solution, the cation-bridging contributed to the promotion effects of DDAB or Tween 80 on TC mobility. Interestingly, SDBS considerably suppressed TC transport due to the precipitation of SDBS-Cu²⁺ complexes onto sand surfaces. Moreover, the enhancement order of surfactants at pH 5.0 was similar to that pH 7.0. However, DDAB could inhibit TC transport in sand columns at pH 9.0, which were mainly caused by the decrease of electrostatic repulsion and the hydrophobicity induced by the binding cationic surfactant. Findings from this work provide novel insight into involvement of surfactants in antibiotic transport behaviors in the subsurface environment.

Transport of tetracycline in saturated porous media: combined functions of inorganic ligands and solution pH

To date, there is still very little knowledge about the combined effects of typical inorganic ligands and solution pH values on mobility characteristics of tetracycline (TC) through saturated aquifer media. In this work, three typical inorganic ligands (i.e., phosphate, silicate, and iodate) were employed in the transport experiments. Generally, all the ligands promoted TC mobility over the pH range of 5.0-9.0 owing to the enhanced electrostatic repulsion between sand grains and TC anionic forms (i.e., TC^- and TC^2-) as well as the competitive deposition between ligands and antibiotic molecules for attachment sites. Furthermore, the transport-enhancement effects of ligands on TC intensively depended on ligand type and followed the sequence of phosphate > silicate > iodate. This phenomenon was ascribed to their different molecular sizes and binding abilities to sand grains. Interestingly, the differences in extents of enhanced effects of various inorganic ligands on TC transport varied with background solution pH due to pH-induced different extents of deposition site competition effects. Moreover, the two-site nonequilibrium model (which accounts for an equilibrium site and a kinetic site) as well as adsorption and kinetic studies were performed to help interpret the controlling mechanisms for the synergistic effects of inorganic ligands and solution pH on TC transport in saturated quartz sand. The findings of our study clearly demonstrate that inorganic ligands may be critical factors in assessing the fate and transport of antibiotics in groundwater systems.

Colchicine anti-inflammatory therapy for non-intensive care unit hospitalized COVID-19 patients: results from a pilot open-label, randomized controlled clinical trial

Systemic inflammation is a hallmark of severe coronavirus disease-19 (COVID-19). Anti-inflammatory therapy is considered crucial to modulate the hyperinflammatory response (cytokine storm) in hospitalized COVID-19 patients. There is currently no specific, conclusively proven, cost-efficient, and worldwide available anti-inflammatory therapy available to treat COVID-19 patients with cytokine storm. The present study aimed to investigate the treatment benefit of oral colchicine for hospitalized COVID-19 patients with suspected cytokine storm. Colchicine is an approved drug and possesses multiple anti-inflammatory mechanisms. This was a pilot, open-label randomized controlled clinical trial comparing standard of care (SOC) plus oral colchicine (colchicine arm) vs. SOC alone (control arm) in non-ICU hospitalized COVID-19 patients with suspected cytokine storm. Colchicine treatment was initiated within first 48 hours of admission delivered at 1.5 mg loading dose, followed by 0.5 mg b.i.d. for next 6 days and 0.5 mg q.d. for the second week. A total of 96 patients were randomly allocated to the colchicine (n=48) and control groups (n=48). Both colchicine and control group patients experienced similar clinical outcomes by day 14 of hospitalization. Treatment outcome by day 14 in colchicine vs control arm: recovered and discharged alive: 36 (75.0%) vs. 37 (77.1%), remain admitted after 14-days: 4 (8.3%) vs. 5 (10.4%), ICU transferred: 4 (8.3%) vs. 3 (6.3%), and mortality: 4 (8.3%) vs. 3 (6.3%). The speed of improvement of COVID-19 acute symptoms including shortness of breath, fever, cough, the need of supplementary oxygen, and oxygen saturation level, was almost identical in the two groups. Length of hospitalization was on average 1.5 day shorter in the colchicine group. There was no evidence for a difference between the two groups in the follow-up serum levels of inflammatory biomarkers including C-reactive protein (CRP), D-dimer, lactate dehydrogenase (LDH), ferritin, interleukin-6 (IL-6), high-sensitivity troponin T (hs-TnT) and N-terminal pro b-type natriuretic peptide (NT pro-BNP). According to the results of our study, oral colchicine does not appear to show clinical benefits in non-ICU hospitalized COVID-19 patients with suspected cytokine storm. It is possible that the anti-inflammatory pathways of colchicine are not crucially involved in the pathogenesis of COVID-19.

Effect of season and housing systems on various physio-behavioral attributes of local breed of rabbits (Oryctolagus cuniculus) in Southern Punjab, Pakistan

The present study was conducted to investigate the effect of season and various housing systems on behavioral i.e. sitting, standing, walking and physiological i.e. respiratory rate (RR), rectal temperature (RT), time of sexual libido (TSL) attributes of local breed of rabbits reared in Southern Punjab, Pakistan. Adult rabbits (n = 40) of 6 month to 1 year old were divided into two groups (n = 20 / group). Group I was placed under traditional colony system in the soil while group II was kept under modern cage system. Sitting and standing was significantly (p ≤ 0.05) higher during summer and winter respectively. The RR and RT were significantly (p ≤ 0.05) higher in summer as compared to other study seasons. Standing behavior was significantly (p ≤ 0.05) higher in caged rabbits as compared to colony-reared ones. Statistically higher (p ≤ 0.05) TSL value was observed in summer as compared to other three study seasons. From this study it is concluded that rabbit's behavioral and physiological traits are significantly affected by season and housing systems. We concluded that rabbits show better physio-behavioral performance in autumn and winter season while summer stress negatively affects physiology and behavior under caged-system. This study could contribute new aspects of behavioral and physiological processes in local breed of rabbits due to different seasons and housing systems.

Effect of Zinc Dialkyl Dithiophosphate Replenishment on Tribological Performance of Heavy-Duty Diesel Engine Oil

Soot is the main contamination that affects oil performance and increases the frequency of oil changes in heavy-duty engine oil. Several studies discussed that additive concentration in engine oil can be influenced due to additive depletion over time and additive adsorption on soot particles. To extend oil drain intervals and improve oil performance, filter manufactures explore removing the soot to a certain level and replenishing the consumed additives. Zinc dialkyl dithiophosphate (ZDDP) is one of the most favored antiwear additives that react very rapidly with rubbing surfaces to form tribofilm that reduces wear. In this study, the experimental work aims to investigate the effect of ZDDP replenishment on tribological performance in the existence of soot and after removing soot from heavy-duty used oil. The study reveals that reclaiming the used oil can be achieved by removing the soot to a certain level. The results demonstrate that the reclaimed oil after removing soot is still not as good as the fresh oil. This study proves that additive depletion, additive adsorption on soot, and the decomposition of antiwear additive adversely influence the reclaimed oil performance. However, replenishing the consumed additive by adding a small amount of ZDDP helps to improve the reclaimed oil performance compared to a large amount of ZDDP which is required to re-gain the oil performance in the existence of soot.

A preliminary study on devising a hematological formula for estimation of hemoglobin from packed cell volume in beetal goats

ABSTRACT The study was devised with the aim to evaluate the relationship between hemoglobin (Hb) concentration and Packed Cell Volume (PCV) in beetal goats being reared under pastoralism. It also aims to devise a hematological formula for estimation of Hb from PCV. Female (n=59) and male goats (n=41) were bled for PCV determination through microhematocrit method, and Hb estimation through Sahli’s hemoglobinometer (HbD) as well as through calculation being 1/3rd of PCV (HbC). The HbD and HbC were statistically non-significant (P≥0.05) for male and female beetal goats. Overall, significantly (P≤0.01) positive correlation coefficient was noticed between HbD and PCV, and between HbD and HbC (r=0.75; adjusted r-square=0.57). As the overall model predicted that 57% variability in HbD could be deduced from PCV, hence, in order to enhance the prediction probability, the regression equation i.e. Hb concentration= 0.24(PCV) +1.5 was utilized to deduce corrected hemoglobin (CHb). The comparison of this CHb with HbD gave a non-significant (P≤0.05) difference. Similarly, linear regression of CHb with PCV gave a 99% prediction. We accordingly recommend a simplified pen-side hematological formula for deducing Hb concentration from PCV viz. Hb concentration= 0.24(PCV) +1.5 for beetal goats instead of its calculation as one-third of PCV.

Insights into the molecular mechanism of tetracycline transport in saturated porous media affected by low-molecular-weight organic acids: Role of the functional groups and molecular size

The transport of tetracycline possessed a great challenge in its environmental applications. This study looked at how various low-molecular-weight organic acids (LMWOAs) affect the transport of tetracycline in environments. To that end, four LMWOAs were employed in experiments; acetic acid, malonic acid, malic acid, and citric acid. It was observed that LMWOAs promoted the tetracycline passage in presence of various experimental environments. The LMWOAs steric hindrance and deposition competition facilitated tetracycline transport at pH 5.0. The other deposition mechanism for tetracycline was the electrostatic repulsion between tetracycline and sand enhanced by deprotonated LMWOAs at pH 7.0. Moreover, the enhanced effects of LMWOAs on tetracycline mobility were intensively dependent on LMWOA type with more functional groups (e.g. carboxyl and hydroxyl groups) and larger molecular size supported stronger deposition competition, steric hindrance as well as electrostatic repulsion. Additionally, cation-bridging played a vital role for the enhanced effects of LMWOAs on tetracycline transport with divalent cations (e.g., Ca²⁺ and Pb²⁺). Interestingly, tetracycline exhibited a higher mobility in the presence of Ca²⁺ relative to Pb²⁺ regardless of LMWOAs-free or LMWOAs-addition. This phenomenon was attributed to the fact that Pb²⁺ has a greater affinity with tetracycline and LMWOAs than Ca²⁺. Furthermore, under the shadow of numerous LMWOAs, the non-equilibrium two site transportation model was employed to investigate the movement of tetracycline in porous saturated media. The present study suggests that LMWOAs may be important considerations in assessing the antibiotic passage in soil as well as groundwater.

Enhancement in reactivity via sulfidation of FeNi@BC for efficient removal of trichloroethylene: Insight mechanism and the role of reactive oxygen species

A novel catalyst of sulfidated iron-nickel supported on biochar (S-FeNi@BC) was synthesized to activate persulfate (PS) for the removal of trichloroethylene (TCE). A number of techniques including XRD, SEM, TEM, FTIR, BET and EDS were employed to characterize S-FeNi@BC. The influence of sulfur to iron ratio (S/F) on TCE removal was investigated by batch experiments and a higher TCE removal (98.4%) was achieved at 0.22/1 ratio of S/F in the PS/S-FeNi@BC oxidation system. A dominant role in iron species conversion was noticed by the addition of sulfur in FeNi@BC system. Significant enhancement in recycling of the dissolved and surface Fe(II) was confirmed which contributed to the generation of free and surface-bound active radical species (OH, O₂^-, ¹O₂, SO₄^-). Further, the presence and contribution of these radicals were validated by the electron paramagnetic resonance (EPR) and quenching study. In addition, XPS results demonstrated the dominant role of S(-II) with the increase of Fe(II) from 36.3% to 58.6% and decrease of Fe(III) from 52.1% to 39.8% in the PS/S-FeNi@BC system. In crux, the influence of initial pH, catalyst dosage, oxidant dosage, and inorganic ions (HCO₃^-, Cl^-, NO₃^- and SO₄^2-) on TCE removal was also investigated. The findings obtained from this study suggest that S-FeNi@BC is an appropriate catalyst to activate PS for TCE contaminated groundwater remediation.

Investigation on optical temperature sensing behaviour via Ag island-enhanced luminescence doped β-NaGdF4:Yb3+/Tm3+ films/microfibers

In this study, silver (Ag) island modified up-conversion nano-particle (NaGdF₄:Yb³⁺/Tm³⁺) thin films were prepared via electrostatic layer by layer (LBL) and spin coating techniques. The spectroscopic results indicated that adding Ag nanoparticles could significantly enhance the up-conversion emission of NaGdF₄:Yb³⁺/Tm³⁺ thin films at 452 nm and 476 nm. The maximum enhancement factor of ∼15.6 was reached at 476 nm. Furthermore, we prepared microfibers from upconverting nanoparticles solution, the application of microfibers as active and passive waveguides was analyzed by observing the performance of microfibers with and without Ag under 980 nm excitation of the laser source. The fluorescence intensity ratio (FIR) method was adopted to evaluate microfiber sensitivity. The intensity-based temperature sensitivity of blue emission from a single microfiber containing up-conversion nanomaterials (NaGdF₄:Yb³⁺/Tm³⁺) and Ag nanoparticles reached up to 0.018 K⁻¹ at 310 K compared to 0.0029 K⁻¹ in Ag-free microfiber. Our results suggest that the novel material can be used to construct new nano-thermometers, useful both in biological experiments as well as industrial research.

In this study, silver (Ag) island modified up-conversion nano-particle thin films were prepared via electrostatic layer by layer (LBL) and spin coating techniques.

First Report of Aspergillus niger causing Black rot of Grapes in Pakistan

In June 2015 & 2016, a postharvest survey of table grapes (Vitis vinifera) cv. King's Ruby, was carried out in five different commercial fruit markets of Rawalpindi (33°38'19.2″N, 73°01'45.0″E) district, Punjab Province. Symptoms appeared as brownish lesions with black sporulation on grapes berries. The incidence of these symptoms on bunches ranged from 12 to 17% at all sites. Symptomatic tissue pieces were surface-sterilized with 0.1% sodium hypochlorite (NaOCl) for 30 seconds, rinsed three times with sterile distilled water, dried on filter paper for 45 seconds, and incubated on potato dextrose agar (PDA) at 25°C. After 3 days, dark brown to black mycelium were formed on PDA media. A total of 24 isolates were examined morphologically. The apex of the conidiophore was observed to be radiate. Vesicles were found to be spherical and covered with irregular metulae and phialides. Conidia were globose or subglobose measured (3.14 μm ± 2.24 in averaged diameter: n=50), dark brown to black, with roughened cell walls. The conidiophores were also smooth-walled, hyaline, and became melanized toward the vesicle. These characteristics of the fungus were similar to those described for Aspergillus niger van Tiegh (de Hoog et al. 2000). For molecular identification, the internal transcribed spacer (ITS) region, beta-tubulin (Bt) gene and partial RNA polymerase II largest subunit (RPB2) gene of representative isolate (Asp.n02) was amplified using primers ITS1/ITS4, BT2a/BT2b and RPB2-6F/RPB2-7R respectively (White et al., 1990; Glass & Donaldson, 1995; Liu et al. 1999). Sequences were deposited in GenBank (ITS, MN658871; Bt2, MT117924; and RPB2, MT318289). Based on BLAST analysis, sequences of the ITS region, Bt2 genes, and RPB2 gene showed 99 to 100% similarity of isolate Asp.n02 to Aspergillus niger (Accession Nos. MK307680.1, MN195121.1, MF078661.1 for ITS gene, MN567299.1, MK451029.1, MK451020.1 for Bt2 gene, and MK450788.1, MK450790.1 for RPB2 gene). To complete Koch's postulates, 10-µl aliquots of spore suspensions (106 spores/ml) of isolate: Asp.n 02 was pipetted onto three non-wounded and four wounded (5 mm diam) asymptomatic grape berries cv. King's Ruby (seven berries per isolate), Sterile distilled water was applied to asymptomatic berries similaries to serve as a negative control (Ghuffar et al. 2018; Jayawardena et al. 2018). Berries were incubated at 25 ± 2°C in sterile moisture chambers, and the experiment was conducted twice. Brownish lesions leading to black sporulation similar to the original symptoms were observed on both wounded and non-wounded inoculated berries after 3 days, whereas no symptoms were recorded on the negative control. The morphology of the fungus that was re-isolated from each of the inoculated berries was identical to that of the original cultures. Aspergillus niger was reported previously in Europe and Israel causing mycotoxin (Ochratoxin A) OTA production on Table grapes (Bau et al. 2006). To our knowledge, this is the first report of Aspergillus niger causing black rot of grapes in Pakistan. This finding will help to plan effective disease management strategies against the black rot of grapes in Pakistan.

First Report of Aspergillus niger causing Black rot of Grapes in Pakistan

In June 2015 & 2016, a postharvest survey of table grapes (Vitis vinifera) cv. King's Ruby, was carried out in five different commercial fruit markets of Rawalpindi (33°38'19.2″N, 73°01'45.0″E) district, Punjab Province. Symptoms appeared as brownish lesions with black sporulation on grapes berries. The incidence of these symptoms on bunches ranged from 12 to 17% at all sites. Symptomatic tissue pieces were surface-sterilized with 0.1% sodium hypochlorite (NaOCl) for 30 seconds, rinsed three times with sterile distilled water, dried on filter paper for 45 seconds, and incubated on potato dextrose agar (PDA) at 25°C. After 3 days, dark brown to black mycelium were formed on PDA media. A total of 24 isolates were examined morphologically. The apex of the conidiophore was observed to be radiate. Vesicles were found to be spherical and covered with irregular metulae and phialides. Conidia were globose or subglobose measured (3.14 μm ± 2.24 in averaged diameter: n=50), dark brown to black, with roughened cell walls. The conidiophores were also smooth-walled, hyaline, and became melanized toward the vesicle. These characteristics of the fungus were similar to those described for Aspergillus niger van Tiegh (de Hoog et al. 2000). For molecular identification, the internal transcribed spacer (ITS) region, beta-tubulin (Bt) gene and partial RNA polymerase II largest subunit (RPB2) gene of representative isolate (Asp.n02) was amplified using primers ITS1/ITS4, BT2a/BT2b and RPB2-6F/RPB2-7R respectively (White et al., 1990; Glass & Donaldson, 1995; Liu et al. 1999). Sequences were deposited in GenBank (ITS, MN658871; Bt2, MT117924; and RPB2, MT318289). Based on BLAST analysis, sequences of the ITS region, Bt2 genes, and RPB2 gene showed 99 to 100% similarity of isolate Asp.n02 to Aspergillus niger (Accession Nos. MK307680.1, MN195121.1, MF078661.1 for ITS gene, MN567299.1, MK451029.1, MK451020.1 for Bt2 gene, and MK450788.1, MK450790.1 for RPB2 gene). To complete Koch's postulates, 10-µl aliquots of spore suspensions (106 spores/ml) of isolate: Asp.n 02 was pipetted onto three non-wounded and four wounded (5 mm diam) asymptomatic grape berries cv. King's Ruby (seven berries per isolate), Sterile distilled water was applied to asymptomatic berries similaries to serve as a negative control (Ghuffar et al. 2018; Jayawardena et al. 2018). Berries were incubated at 25 ± 2°C in sterile moisture chambers, and the experiment was conducted twice. Brownish lesions leading to black sporulation similar to the original symptoms were observed on both wounded and non-wounded inoculated berries after 3 days, whereas no symptoms were recorded on the negative control. The morphology of the fungus that was re-isolated from each of the inoculated berries was identical to that of the original cultures. Aspergillus niger was reported previously in Europe and Israel causing mycotoxin (Ochratoxin A) OTA production on Table grapes (Bau et al. 2006). To our knowledge, this is the first report of Aspergillus niger causing black rot of grapes in Pakistan. This finding will help to plan effective disease management strategies against the black rot of grapes in Pakistan.

Numerical simulations of a falling film on the inner surface of a rotating cylinder

A flow in which a thin film falls due to gravity on the inner surface of a vertical, rotating cylinder is investigated. This is performed using two-dimensional (2D) and 3D direct numerical simulations, with a volume-of-fluid approach to treat the interface. The problem is parameterized by the Reynolds, Froude, Weber, and Ekman numbers. The variation of the Ekman number (Ek), defined to be proportional to the rotational speed of the cylinder, has a strong effect on the flow characteristics. Simulations are conducted over a wide range of Ek values (0≤Ek≤484) in order to provide detailed insight into how this parameter influences the flow. Our results indicate that increasing Ek, which leads to a rise in the magnitude of centrifugal forces, produces a stabilizing effect, suppressing wave formation. Key flow features, such as the transition from a 2D to a more complex 3D wave regime, are influenced significantly by this stabilization and are investigated in detail. Furthermore, the imposed rotation results in distinct flow characteristics such as the development of angled waves, which arise due to the combination of gravitationally and centrifugally driven motion in the axial and azimuthal directions, respectively. We also use a weighted residuals integral boundary layer method to determine a boundary in the space of Reynolds and Ekman numbers that represents a threshold beyond which waves have recirculation regions.

Seroprevalence of Toxoplasma gondii and associated hematological alterations in small ruminants of D.G. Khan district of Southern Punjab, Pakistan

ABSTRACT The present study was carried out to evaluate the prevalence and hematological effects of Toxoplasma gondii in sheep and goat in district Dera Ghazi Khan. Blood samples (n=204) were collected comprise goats (n=101) and sheep (n=103) alongwith age, gender and breeds of animals. Samples were collected randomly from 25 flocks of 7 different union council Viz. Vehova, Tibbi Qaisrani, Lakhani, Kohar, Tuman Qaisrani, Nutkani and Kot Qaisrani of Tehsil Taunsa Sharif at least 4 animals from each flock. All ruminants divide into three groups based on age, breed and gender. The prevalence was detected through two different kits Viz. LAT and ELISA kit. The overall prevalence suspected in goats through LAT and ELISA kit was (35.64%), (32.67%) and in sheep was (25.24%), (23.30%) respectively. The Toxoplasma gondii had a significant effect on goats in age groups and non-significant all other groups of goats and sheep. Toxoplasma gondii had a significant effect on all hematological parameters like Hemoglobin, total leukocyte cells, granulocytes, lymphocytes, platelets, and red blood cells, except monocytes. In conclusion of the current study, toxoplasmosis is prevalent among ruminants, reveals the possibility of transmission to humans on the use of host animals as protein source.

Emergence of preconfigured and plastic time-compressed sequences in early postnatal development

When and how hippocampal neuronal ensembles first organize to support encoding and consolidation of memory episodes, a critical cognitive function of the brain, are unknown. We recorded electrophysiological activity from large ensembles of hippocampal neurons starting on the first day after eye opening as naïve rats navigated linear environments and slept. We found a gradual age-dependent, navigational experience-independent assembly of preconfigured trajectory-like sequences from persistent, location-depicting ensembles during postnatal week 3. Adult-like compressed binding of adjacent locations into trajectories during navigation and their navigational experience-dependent replay during sleep emerged in concert from spontaneous preconfigured sequences only during early postnatal week 4. Our findings reveal ethologically relevant distinct phases in the development of hippocampal preconfigured and experience-dependent sequential patterns thought to be important for episodic memory formation.

Strengthened Temporal Coordination within Pre-existing Sequential Cell Assemblies Supports Trajectory Replay

A central goal in learning and memory research is to reveal the neural substrates underlying episodic memory formation. The hallmark of sequential spatial trajectory learning, a model of episodic memory, has remained equivocal, with proposals ranging from de novo creation of compressed sequential replay from blank slate networks to selection of pre-existing compressed preplay sequences. Here, we show that increased millisecond-timescale activation of cell assemblies expressed during de novo sequential experience and increased neuronal firing rate correlations can explain the difference between post-experience trajectory replay and robust preplay. This increased activation results from an improved neuronal tuning to specific cell assemblies, higher recruitment of experience-tuned neurons into pre-existing cell assemblies, and increased recruitment of cell assemblies in replay. In contrast, changes in overall neuronal and cell assembly temporal order within extended sequences do not account for sequential trajectory learning. We propose the coordinated strengthening of cell assemblies played sequentially on robust pre-existing temporal frameworks could support rapid formation of episodic-like memory.

Accreditation and evaluation of veterinary medical institutes - a Pakistani perspective

The Higher Education Commission of Pakistan (HEC) is an independent, autonomous and constitutionally established institution that provides primary funding for higher education in Pakistan, which it also oversees, regulates and accredits. According to the HEC Charter: 'the HEC of Pakistan may set up national or regional evaluation councils or authorise any existing council/or similar body to carry out accreditation of institutions including their departments, facilities and disciplines by giving them appropriate ratings'. At present, 14 accreditation bodies operate under the umbrella of the HEC. Five were established under the HEC's Quality Assurance Agency, while nine councils associated with the accreditation and evaluation of medical institutes are independent bodies that were extant before the HEC was created, and are recognised by the HEC. The authors will discuss the role of the Pakistan Veterinary Medical Council (PVMC), the accreditation of veterinary institutes and associated issues of concern. They suggest that the PVMC should adopt an unbiased approach to new and established veterinary institutes to attain uniform accreditation of all veterinary institutes throughout the country. In addition, the government should consult the accreditation councils and professional bodies before setting up new institutes. The authors also suggest that, instead of placing new veterinary institutes under the aegis of non-veterinary universities, they should be made sub-campuses of established veterinary universities. In time, they will emerge as established institutes in their own right.

Synergistic potential of propolis and vitamin e against sub-acute toxicity of AlCl(3) in albino mice: in vivo study

Current study evaluated the synergistic potential of propolis and vitamin E against sub-acute toxicity of aluminum chloride on different biochemical parameters and liver histology. Swiss albino mice (n=42) were randomly divided into seven groups. Group I received 0.2 ml of 0.9 % saline solution, Group II received Propolis (50 mg/kg b.w.), Group III received vitamin E (150 mg/kg b.w.), Group IV received AlCl(3) 50 mg/kg b.w., Group V received AlCl(3) + Propolis, Group VI received AlCl(3) + vitamin E and Group VII received AlCl(3) + propolis + vitamin E. Blood and tissue samples were collected after 7 and 21 days. The body weight of the animals significantly increased in all groups except Group IV. The concentration of serum high density lipoprotein significantly decreased in Group IV and increased in Group V, VI and VII. The level of aspartate aminotransferase, alanine transferase, alkaline phosphatase, triglycerides, total cholesterol, and low density lipoprotein significantly increased in AlCl(3) treated group and increased in Group V, VI and VII. Tissue sections were processed and stained by hematoxylin and eosin. Group II showed cellular necrosis. Group V, VI showed decreased number of vacuolization, sinusoidal spacing and macrophage cell infiltration. Group VI showed less degenerative changes in the third week. Vitamin E and propolis in combination with Al provides more protection against AlCl(3) induced toxicity.

The impact of surface properties and dominant ions on the effectiveness of G-nZVI heterogeneous catalyst for environmental remediation

The surface properties of nanocomposites are influenced by the existence of inorganic species that may affect its performance for specific catalytic applications. The impact of different ionic species on particular catalytic activity had not been investigated to date. In this study, the surface charge (zeta potential) of graphene-oxide-supported nano zero valent iron (G-nZVI) was tested in definitive cationic (Na⁺, K⁺, Ca²⁺ and Mg²⁺) and anionic (Br^-, Cl^-, NO₃^-, SO₄^2-, and HCO₃^-) environments. The efficiency of G-nZVI catalyst was inspected by measuring the generation of reactive oxygen species (ROS) for the degradation of 1,1,1-trichloroethane (TCA) in sodium percarbonate (SPC) system. Tests conducted using probe compounds confirmed the generation of OH and O₂^- radicals in the system. In addition, the experiments performed using scavenging agents certified that O₂^- were primary radicals responsible for TCA removal, along with prominent contribution from OH radicals. The study confirmed that G-nZVI catalytic capability for TCA degradation is notably affected by various cationic species. The presence of Ni²⁺ and Cu²⁺ significantly enhanced (94%), whereas Na⁺ and K⁺ had minor effects on TCA removal. Overall, the results indicated that groundwater ionic composition may have low impact on the effectiveness of G-nZVI-catalyzed peroxide TCA treatment.

Enhanced degradation of trichloroethylene in oxidative environment by nZVI/PDA functionalized rGO catalyst

Nano zero-valent iron (nZVI) particles with higher reactivity have been recognized as more efficient catalysts than Fe(II) for the groundwater remediation. The rapid emergence of novel catalyst supports efficiently prevent the rapid aggregation of nZVI and further improve catalytic reactivity. However, the lack of ability to avoid the potential oxidation of bare nZVI-support structure in air environment hinders its wider application in the actual contaminated sites. In this study, nZVI on reduced graphene oxide (rGO) functionalized by polydopamine (PDA) (nZVI-PDA@rGO) was synthesized successfully and applied into sodium persulfate (SPS), potassium monopersulfate (PMS) and H₂O₂ oxidative environments to remove trichloroethylene (TCE). For comparison, nZVI supported on solely rGO was prepared. The XRD test displayed the stronger stability of α-Fe(0) in nZVI-PDA@rGO catalyst against oxidation exposed to air. Compared with nZVI-rGO, a core shell structure of nZVI-PDA@rGO was observed in TEM image obviously. The dosage tests showed nZVI-PDA@rGO had a better catalytic reactivity than nZVI-rGO for TCE removal at lower catalyst and oxidant dosages, i.e. PMS dosage: 0.3 mM, catalyst dosage: 50 mg L^-1, TCE removal: 45.0% (nZVI-rGO) up to 99.6% (nZVI-PDA@rGO). TCE removal mechanisms were revealed through radical scavenger tests, demonstrating sulfate radicals played more important role in nZVI-PDA@rGO catalyzed-oxidant systems.