Soil amended with Algal Biochar Reduces Mobility of deicing salt contaminants in the environment: An atomistic insight.

Soil-based filter media in green infrastructure buffers only a minor portion of deicing salt in surface water, allowing most of that to infiltrate into groundwater, thus negatively impacting drinking water and the aquatic ecosystem. The capacity of the filter medium to adsorb and fixate sodium (Na+) and chloride (Cl-) ions has been shown to improve by biochar amendment. The extent of improvement, however, depends on the type and density of functional groups on the biochar surface. Here, we use density functional theory (DFT) and molecular dynamics (MD) simulations to show the merits of biochar grafted by nitrogenous functional groups to adsorb Cl-. Our group has shown that such functional groups are abundant in biochar made from protein-rich algae feedstock. DFT is used to model algal biochar surface and its possible interactions with Cl- through two possible mechanisms: direct adsorption and cation (Na+)-bridging. Our DFT calculations reveal strong adsorption of Cl- to the biochar surface through hydrogen bonding and electrostatic attractions between the ions and active sites on biochar. MD results indicate the efficacy of algal biochar in delaying chloride diffusion. This study demonstrates the potential of amending soils with algal biochar as a dual-targeting strategy to sequestrate carbon and prevent deicing salt contaminants from leaching into water bodies.

Biocementation of soils of different surface chemistries via enzyme induced carbonate precipitation (EICP): An integrated laboratory and molecular dynamics study.

Biocementation is a ground improvement technique that involves precipitating a mineral (commonly calcium carbonate, CaCO3) in the soil pore space to bind soil particles, in turn increasing the strength and reducing the permeability of the soil. Ureolysis (i.e. hydrolysis of urea) is the most researched calcium carbonate precipitation mechanism, which can be induced through either a microbial (MICP) or enzymatic (EICP) process. While laboratory tests and field trials have provided strong evidence of the efficacy of biocementation in strengthening granular materials, the role of the precipitate-grain interface and the surface chemistry of soil grains in biocementation are largely unknown. This study aims to address this gap. To this end, two geotechnically similar sand samples differing considerably in the amount of iron oxide and iron sulfate on grain surface are biocemented via EICP and tested for unconfined compressive strength (UCS). The biocemented sample containing a high concentration of iron oxide and iron sulfate exhibits almost 50% lower UCS than the other sample. To investigate whether surface chemistry can explain this considerable difference, interactions of CaCO3 with quartz (SiO2), hematite (Fe2O3), and marcasite (FeS2) as polymorphs of silicon dioxide, iron oxide, and iron sulfide, respectively, are simulated using molecular dynamics. The influence of water content at the precipitate-grain interface is also considered. Simulation results indicate that in dry conditions, CaCO3 has almost two times stronger affinity for SiO2 than Fe2O3 and FeS2, suggesting that biocementation is most effective for clean sands. It is also shown that water reduces the precipitate-grain adhesion.

Interactions of SARS-CoV-2 with inanimate surfaces in built and transportation environments.

Understanding the interactions and transmission of pathogens with/via inanimate surfaces common in the built environment and public transport vehicles is critical to promoting sustainable and resilient urban development. Here, molecular dynamics (MD) simulations are used to study the adhesion of SARS-CoV-2 (the causative agent of COVID-19) to some of these surfaces at different temperatures (same for surfaces and ambiance) ranging from -23 to 60 °C. Surfaces simulated are aluminum, copper, copper oxide, polyethylene (PE), and silicon dioxide (SiO2). Steered MD (SMD) simulations are also used to investigate the transfer of the virus from PE and SiO2 when a contaminated surface is touched. The virus shows the lowest and highest adhesions to PE and SiO2, respectively (20 vs 534 eV). Influence of temperature is not found to be noticeable. Using simulated water molecules to represent moisture on the skin, SMD simulations show that water molecules can lift the virus from the PE surface but damage the virus when lifting it from the the SiO2 surface. The results suggest that the PE surface is a more favorable surface to transmit the virus than the other surfaces simulated in this study. The results are compared with those reported in a few experimental studies.

Role of thalamic ventral posterolateral nucleus histamine H2 and opiate receptors in modulation of formalin-induced muscle pain in rats.

BACKGROUND: Histamine and opiate systems contribute to supraspinal processing of pain. In the present study, we investigated the effects of microinjection of histamine and agonists and antagonists of histamine H2 and opiate receptors into the thalamic ventral posterolateral nucleus on muscle pain in rats. METHODS: The thalamic ventral posterolateral nuclei were bilaterally implanted with two guide cannulas. Muscle pain was induced by intramuscular injection of a diluted formalin solution (2.5%, 50µl) into the belly of gastrocnemius muscle, and pain-related behaviors including paw licking duration and paw flinching number were recorded at five-min blocks for 60min. RESULTS: Formalin produced a biphasic pattern of pain-related behaviors. Ranitidine (a histamine H2 receptor antagonist) alone did not affect pain intensity, whereas it prevented the antinociceptive activities of histamine, dimaprit (a histamine H2 receptor agonist) and morphine (an opiate receptor agonist). Naloxone (an opiate receptor antagonist) alone increased pain, and inhibited histamine-, dimaprit-, and morphine-induced antinociception. Locomotor activity was not changed with these chemicals. CONCLUSIONS: Our results showed an interaction between histamine H2 and opiate receptors at the thalamic ventral posterolateral nucleus in modulation of muscle pain.

The role of histamine H1, H2 and H3 receptors of ventral posteromedial nucleus of thalamus in modulation of trigeminal pain.

Histamine receptors are involved in supraspinal modulation of pain. In the present study, we investigated the effects of microinjection of histamine H1, H2 and H3 receptor antagonists and agonists into the ventral posteromedial (VPM) nucleus of the thalamus on two models of trigeminal pain. Right and left sides of VPM were implanted with two guide cannulas. Corneal pain was induced by local corneal surface application of hypertonic saline and the number of eye wipes was recorded. The duration of face rubbing, as an orofacial pain measure, was recorded after subcutaneous (s.c.) injection of capsaicin into the vibrissa pad. 2-pyridylethylamine (2-PEA, a histamine H1 receptor agonist, 4µg/site) and dimaprit (a histamine H2 receptor agonist, 1 and 4µg/site) suppressed corneal and orofacial pains. Mepyramine (a histamine H1 receptor antagonist) and ranitidine (a histamine H2 receptor antagonist) at the similar doses of 0.5, 2 and 8µg/site alone had no effects on trigeminal pain. Prior microinjection of mepyramine and ranitidine at a similar dose of 8µg/site inhibited the antinociceptive effects of 2-PEA (4µg/site) and dimaprit (4µg/site), respectively. Immepip (a histamine H3 receptor agonist, 1 and 4µg/site) increased, and thioperamide (a histamine H3 receptor antagonist, 2 and 8µg/site) attenuated nociceptive responses. Prior microinjection of thioperamide (8µg/site) prevented immepip (4µg/site)-induced nociception. These chemicals did not change locomotor behavior. It is concluded that post-synaptic histamine H2, and to a lesser extent H1, receptors and pre-synaptic histamine H3 receptor may be involved in VPM modulation of trigeminal pain.

The effects of crocin and safranal on the yawning induced by intracerebroventricular injection of histamine in rats.

OBJECTIVE: Crocin and safranal, as the major constituents of saffron, have many biological activities. This study investigated the effects of crocin and safranal on yawning response induced by intracerebroventricular (i.c.v.) injection of histamine in rats. MATERIALS AND METHODS: In ketamine/xylazine-anesthetized rats, a guide cannula was implanted in the right ventricle of the brain and yawning induced by i.c.v. injection of histamine. Crocin and safranal were intraperitoneally (i.p.) injected alone and before i.c.v. injection of histamine. RESULTS: Histamine at the doses of 10 and 20 µg/rat produced yawning. Mepyramine (a histamine H1 receptor antagonist) 40 µg/rat significantly (p<0.05) prevented histamine (20 µg/rat)-induced yawning. Crocin (30 mg/kg) and safranal (1 mg/kg) significantly (p<0.05) increased histamine (10 µg/rat)-induced yawning. Crocin and safranal also induced yawning when injected before mepyramine plus histamine administration. CONCLUSION: The results of the present study showed a yawning-inducing effect for central histamine, which was inhibited by mepyramine. Crocin and safranal increased histamine-induced yawning, and also produced yawning when the histamine action is blocked.

Tiotropium effects on airway inflammatory events in the cat as an animal model for acute cigarette smoke-induced lung inflammation.

BACKGROUND: Chronic obstructive pulmonary disease is an inflammatory lung disease mainly caused by tobacco smoke inhalation. METHODS: Fifteen healthy adult male cats were categorized into 3 groups: (1) control group, (2) exposed to cigarette smoke (CS), and (3) exposed to CS treated with tiotropium. RESULTS: Increases in clinical signs and airway responsiveness in CS cats were found compared to control animals. The airway hyperresponsiveness and clinical signs were significantly attenuated by treatment with tiotropium. The CS-induced pulmonary release of interleukin-6, interleukin-8, monocyte chemotactic protein-1, and tumor necrosis factor alpha was reduced in the tiotropium group. Exposure to CS significantly increased total inflammatory cells number in bronchoalveolar lavage fluid, which was significantly attenuated by treatment with tiotropium. The number of macrophages, eosinophils and neutrophils and lymphocytes was increased after exposure to CS. Tiotropium significantly reduced the number of all these cells. Perivascular, peribronchiolar infiltration of inflammatory cells and Reid index increased in the CS group. Treatment with tiotropium significantly reduced these parameters to control level. Enhanced lipid peroxidation with concomitant reduction of antioxidants status was observed in the CS group. Tiotropium significantly reduced the serum, lung lavage, lung, and tracheal tissue lipid peroxides to near control levels. Tiotropium also decreased lung and tracheal protein leakage, and prevented the reduction of total antioxidant status in serum, lung lavage, lung and tracheal tissue of the CS group. CONCLUSION: Cigarette smoke increases airway responsiveness and inflammation in a cat model of CS induced lung inflammation. It can effectively be reduced by treatment with tiotropium.

Investigating the anxiety level in Iranian medical residents in 2010-2011.

BACKGROUND: University entrance is accompanied by major changes in social relationship, rules, and expectations that lead to psychological disorders in susceptible students. The goal of this research is to study the anxiety rate in Iranian medical residents in 2010-2011. METHODS: This study is a cross-sectional, descriptive study. It contains 370 medical residents from the 1(st) year to the 4(th) year of medical universities in Isfahan, Gilan, Zahedan, Sanandaj, and Kashan. The stratified sampling method proportionate to volume of participants is used in this study. The information is collected based on researchers' questioners and Zung self-rating anxiety scale and analyzed with the use of spss software version 16, addition to descriptive and analytic tests (Pearson, one-way analysis of variance, t-test). Meaningful level is regarded as P ≤ 0.05. RESULTS: The study showed that more than 92% of residents participated in the study did not demonstrate anxiety. Among 370 subjects 5.5% presented with mild symptoms of anxiety and no one had symptom of severe anxiety. A meaningful statistical relationship was observed between anxiety and sex, major of study and the city of study (P < 0.05). The results showed a positive meaningful relationship between the number of visits and the score of anxiety. On average the number of night floats were two in 1 week and the number of patient visit was 19 in the past 24 h. A meaningful statistical relationship between anxiety score and number of patient visits was observed. CONCLUSIONS: The anxiety rate in medical students in this study compared to the findings of previous studies reveled very low anxiety in medical residents. The low rate of anxiety could be attributed to the sense of job security and the hope for a better future among residents. The high percentage of anxiolytics abuse and absence of anxiety producing factors among residents in addition to inaccurate response to the questionnaire may all contribute to the low rate of anxiety in this study.