Killing Process Research Articles

Artificial Bacteriophages for Treating Oral Infectious Disease via Localized Bacterial Capture and Enhanced Catalytic Sterilization.

With the rapid emergence of antibiotic-resistant pathogens, nanomaterial-assisted catalytic sterilization has been well developed to combat pathogenic bacteria by elevating the level of reactive oxygen species including hydroxyl radical (·OH). Although promising, the ultra-short lifetime and limited diffusion distance of ·OH severely limit their practical antibacterial usage. Herein, the rational design and preparation of novel virus-like copper silicate hollow spheres (CSHSs) are reported, as well as their applications as robust artificial bacteriophages for localized bacterial capture and enhanced catalytic sterilization in the treatment of oral infectious diseases. During the whole process of capture and killing, CSHSs can efficiently capture bacteria via shortening the distance between bacteria and CSHSs, produce massive ·OH around bacteria, and further iinducing the admirable effect of bacterial inhibition. By using mucosal infection and periodontitis as typical oral infectious diseases, it is easily found that the bacterial populations around lesions in animals after antibacterial treatment fall sharply, as well as the well-developed nanosystem can decrease the inflammatory reaction and promote the hard or soft tissue repair. Together, the high Fenton-like catalytic activity, strong bacterial affinity, excellent antibacterial activity, and overall safety of the nanoplatform promise its great therapeutic potential for further catalytic bacterial disinfection.

Killing three birds with one stone: A novel valorization strategy for comprehensive utilization of waste titanium gypsum

This study proposed a novel process of killing three birds with one stone for valorizing titanium gypsum, which benefits the reduction of CO2 emissions in cement industries, the production of vaterite CaCO3 as potential feedstock of construction materials, and the fabrication of adsorbent for wastewater treatment. The indirect carbonation process of titanium gypsum was optimized considering the extractant type, extractant concentration, liquid-solid ratio, and temperature. Under the optimal conditions of CH3COONH4 6 M, liquid-solid ratio 15, and temperature 60 °C, the weight loss of titanium gypsum reached 75.01 %. The carbonation efficiency was 97.28 %, and the vaterite CaCO3 was produced. The co-carbonization of leaching residue and waste peanut shell produced biochar-based adsorbent with good adsorption performance of organic pollutants. The removal rate of rhodamine B at 60 min was close to 100 %, while the adsorption capacity reached 468.26 mg/g. The adsorption mechanism was discussed based on adsorption kinetics, isotherms, and characterizations. The economic evaluation of the proposed process clarifies the feasibility of the valorization strategy of waste titanium gypsum.

Aptamin C enhances anti-cancer activity NK cells through the activation of STAT3: a comparative study with vitamin C.

Vitamin C is a well-known antioxidant with antiviral, anticancer, and anti-inflammatory properties based on its antioxidative function. Aptamin C, a complex of vitamin C with its specific aptamer, has been reported to maintain or even enhance the efficacy of vitamin C while increasing its stability. To investigate in vivo distribution of Aptamin C, Gulo knockout mice, which, like humans, cannot biosynthesize vitamin C, were administered Aptamin C orally for 2 and 4 weeks. The results showed higher vitamin C accumulation in all tissues when administered Aptamin C, especially in the spleen. Next, the activity of natural killer (NK) cells were conducted. CD69, a marker known for activating for NK cells, which had decreased due to vitamin C deficiency, did not recover with vitamin C treatment but showed an increasing with Aptamin C. Furthermore, the expression of CD107a, a cell surface marker that increases during the killing process of target cells, also did not recover with vitamin C but increased with Aptamin C. Based on these results, when cultured with tumor cells to measure the extent of tumor cell death, an increase in tumor cell death was observed. To investigate the signaling mechanisms and related molecules involved in the proliferation and activation of NK cells by Aptamin C showed that Aptamin C treatment led to an increase in intracellular STAT3 activation. In conclusion, Aptamin C has a higher capability to activate NK cells and induce tumor cell death compared to vitamin C and it is mediated through the activation of STAT3.

Penerapan Terapi Rendam Kaki Air Hangat Campur Garam dan Serai Pada Pasien Hipertensi di Panti Werdha Dharma Bhakti Palembang

Hypertension is a chronic disease characterized by increased arterial blood pressure. Hypertension cannot be avoided, including in vulnerable groups such as the elderly because as age increases, the risk of hypertension increases so appropriate treatment is needed. Hypertension treatment can be done pharmacologically or non-pharmacologically. Non-pharmacological therapy in this case is foot soak therapy in warm water mixed with salt and lemongrass. The aim of the research is to implement warm water foot soak therapy with salt mixed with lemongrass for hypertensive patients into nursing care. The method used was descriptive with a killing process approach in 3 patients with a one group pretest posttest research design. The results of the warm water foot soak therapy mixed with salt and lemongrass showed a reduction in blood pressure, namely Mrs. N from 148/72mmHg to 138/64mmHg, Mrs. /85mmHg. In conclusion, there was a decrease in blood pressure after the foot soak therapy in warm water mixed with salt and lemongrass.

The use of a penetrative captive bolt device during the killing of farmed saltwater crocodiles (Crocodylus porosus)

ABSTRACT Killing of farmed saltwater crocodiles involve stunning with a penetrative captive bolt device, followed by a cut across the nape of the neck and physical destruction of the brain to ensure death. This study was a welfare-based assessment of the use of a penetrative captive bolt device in saltwater crocodiles, to determine whether it satisfies the criteria of a humane stunning method and can be regarded as a direct killing method without the need for the application of an adjunct method. Methods used were electroencephalogram (EEG), observation of post-stun behavior, and postmortem examination of gross pathology of the cranium and brain. 30 of 30 animals, demonstrated immediate and irreversible loss of consciousness. There was extensive damage to the brain in all animals, deemed to be inconsistent with cortical function and possible recovery. The CASH Special 0.22 penetrative captive bolt pistol (1.25 grain cartridge), applied to the top of the cranial plate, produced immediate and irreversible unconsciousness in all the animals studied. This method satisfies animal welfare expectations, providing crocodile processors with a technique that contributes to a humane killing process.

Glycosylated stimuli responsive polyacrylamide microspheres with in-situ formed AgNPs for bacterial capture, detection and killing

Infections due to multidrug resistant bacteria are a major concern and cause for human mortality worldwide. Materials that can selectively capture, and eliminate these pathogens have turned into a priority. Development of excellent point-of-care material/system that can help in the visual detection of the captured bacterial cells in addition to their killing capability can be advantageous. In this study, we demonstrate the synthesis of a hitherto unknown glycosylated gel microspheres that can capture, kill and detect pathogenic bacteria. Silver nanoparticles (AgNPs) loaded glucose/mannose/galactose functionalized microspheres namely; PAM-Glc, PAM-Man and PAM-Gal, were synthesized by inverse emulsion polymerization. The sugar functionalities present on the microspheres interacts with the bacterial cell wall leading to capture of the cells while the antibacterial action was brought about by the AgNPs synthesized in-situ within the microspheres. The highlight of the designed system is visual indication of bacterial capture due to aggregation of gel microspheres and an indicative colour change of AgNPs. The capture kinetics of bacterial cells using PAM-Man was faster compared to PAM-Glc and PAM-Gal. Among the AgNPs loaded glyco microspheres, silver loaded mannose microspheres (Ag@PAM-Man) exhibited greater inhibition against E. coli and antibiotic resistant S. aureus cells. Bacterial cells captured by PAM-Man, exhibited pink coloration upon interaction with Resorufin β-glucuronide; suggesting the destruction of bacteria upon adhesion to microspheres. The plausible mechanistic aspects involved in the capture, detection and killing process is also discussed.

Antimicrobial Guanidinylate Polycarbonates Show Oral In Vivo Efficacy Against Clostridioides Difficile.

The emerging antibiotic resistance has been named by the World Health Organization (WHO) as one of the top 10 threats to public health. Notably, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VREF) are designated as serious threats, whereas Clostridioides difficile (C. difficile) is recognized as one of the most urgent threats to human health and unmet medical need. Herein, they report the design and application of novel biodegradable polymers - the lipidated antimicrobial guanidinylate polycarbonates. These polymers showed potent antimicrobial activity against a panel of bacteria with fast-killing kinetics and low resistance development tendency, mainly due to their bacterial membrane disruption mechanism. More importantly, the optimal polymer showed excellent antibacterial activity against C. difficile infection (CDI) in vivo via oral administration. In addition, compared with vancomycin, the polymer demonstrated a much-prolonged therapeutic effect and virtually diminished recurrence rate of CDI. The convenient synthesis, easy scale-up, low cost, as well as biodegradability of this class of polycarbonates, together with their in vitro broad-spectrum antimicrobial activity and orally in vivo efficacy against CDI, suggest the great potential of lipidated guandinylate polycarbonates as a new class of antibacterial biomaterials to treat CDI and combat emerging antibiotic resistance.

Advances in traditional Chinese herbal medicine and their pharmacodynamic mechanisms in cancer immunoregulation: a narrative review.

The cancer-immunity cycle (CIC) is defined as a series of progressive events that cause an anticancer immune response leading to the killing of the cancer cell. The concept of CIC has important guiding significance for the clinical and basic tumor immunotherapy research. As one of the methods of traditional Chinese medicine (TCM), Chinese herbal medicine (CHM) has shown unique advantages in multitarget and multipathway immune regulation. However, the tumor immune circulation targeted by CHM is generally unclear at present. To provide reference for future clinical and basic research, we systematically reviewed the existing literature on CHM (including CHM monomers, CHM compounds, and CHM patent medicines) and the mechanisms related to its efficacy. We searched the PubMed and China National Knowledge Infrastructure (CNKI) databases for relevant Chinese-language and English-language literature published from January 1988 to October 2022. The literature was screened manually at three levels: title, abstract, and full text, to identify articles related to CHM and their mechanism of regulating tumor immunity. By further classifying the CIC, it was confirmed that CHM can regulate the activation of dendritic cells (DCs) and macrophages and promote the presentation of tumor antigens. Meanwhile, CHM can also reverse tumor-immune escape by enhancing T-cell proliferation and infiltration. In addition, CHM can also enhance the antitumor ability of the body by regulating the killing process of tumor cells. The theory of a CIC is of guiding significance to regulating tumor immunity via CHM.

Lotus toot extract: An investigation of its antioxidant and anticancer properties for potential application in functional foods

This study investigates the effects of lotus root extract (LRE) on antioxidants and cancer prevention to understand how lotus can be used as a natural ingredient in health-promoting foods. We tested the extract's ability to neutralize harmful molecules using the DPPH assay and found that its effectiveness increases with the amount of extract used. The concentration of 22.21 g/mL was key for the extract to show its protective effects. Additionally, our research showed that LRE is good at removing harmful substances like nitrite (21.14 µg/mL) and hydrogen peroxide (24.91 µg/mL). Importantly, lotus extracts were especially effective against human breast cancer cells. Through MTT analysis at 15.60 g/mL, we found LRE to be very effective in killing these cancer cells. This killing process involves the increase of certain proteins (p53, caspase 3, and 9) and the breaking up of DNA, which are signs of cancer cells being programmed to die. Our findings indicate that LRE could be a strong candidate for cancer prevention. This research sheds light on how lotus root extract could be used in health-promoting foods and suggests it might be worth exploring more as a treatment against cancer.

Theoretical and experimental study of primary cocoon processing

This study is aimed at studying the influence of basic parameters such as the power of ultrasonic waves, the power of infrared radiation, the drying temperature, the drying time and the drying kinetics of cocoons. We used two special methods to kill and dry the cocoons: infrared and combined (infrared-ultrasound). The results obtained indicate that the cocoon drying process as a whole can be controlled by the period of speed decline. With the infrared method, the drying speed increased with increasing temperature, while the power of infrared radiation did not have a strong effect on the killing process. Ultrasound has shown its positive potential in the primary cocoon processing.

Synergism of Cry1Ca toxicity by gut resident Enterococcus spp. in the rice stem borer, Chilo suppressalis

The bacterium Bacillus thuringiensis (Bt) is the most economically successful biopesticide to date, and Bt insecticidal proteins are produced in transgenic crops for pest control. However, relevant details in the Bt-mediated killing process remain undefined. In our previous research, we observed reduced larval susceptibility to Bt Cry1Ca in Chilo suppressalis, a major rice pest in China, after gut microbiota elimination. Here, we tested the hypothesis that gut microbiota, particularly abundant Enterococcus spp., influences C. suppressalis susceptibility to Cry1Ca. We isolated and identified four Enterococcus spp. from C. suppressalis gut microbiota and evaluated their impact on Cry1Ca toxicity. Among the four Enterococcus spp. identified, three of them (E. casseliflavus, E. faecalis, and E. mundtii) dramatically increased larval mortality when introduced in axenic C. suppressalis challenged with Cry1Ca. Gut epithelial damage by Cry1Ca promoted the translocation of Enterococcus spp. from the gut lumen into the hemocoel, where they proliferated and induced larval melanization and hemocyte apoptosis. Our combined findings demonstrate that the presence of specific gut microbiota can greatly affect susceptibility to Cry1Ca through melanization and apoptosis of hemocytes. Better understanding of the Bt intoxication process guides the development of bio-enhancers for Bt-based microbial biopesticides and potential improvement of transgenic crops.

Study on the Effect of Bee Strain and Pollination Method on the Hygienic Behavior of Honey Bee Colonies Tested by Liquid Nitrogen Freezing Method

Bee queen breeding was conducted for local and Carniolan honey bee strains, as well as hybrids resulting from cross-pollination, using both natural and artificial insemination methods. The hygienic behavior test was conducted using liquid nitrogen freezing method. The results showed that the hybrid bee strain T3 outperformed with detection and removal rates of 92.66% and 87.50% respectively, 48 hours after the study, regardless of the insemination method. The results also demonstrated the superiority of the natural insemination method, regardless of the studied strain, with detection and removal rates of 85.66% and 78.66% respectively, 48 hours after the killing process. The results also showed the interaction between the bee strain and the insemination method, 48 hours after the killing process, with significant superiority for treatment T2A1 in terms of detection and removal rates at 98.00% and 96.66% respectively. It was followed by treatment T3A2, which had no significant difference in detection rate (94.33%) and a removal rate of 89.00%, which was not significantly different from treatment T3A1 with a removal rate of 86.00%.

Regulation and distribution of European sea bass perforins point to their role in the adaptive cytotoxic response against NNV

Cell-mediated cytotoxicity is a complex immune mechanism that involves the release of several killing molecules, being perforin (PRF) one of the most important effector players. Perforin is synthesized by T lymphocytes and natural killer cells in mammals and responsible for the formation of pores on the target cell membrane during the killing process. Although perforin has been extensively studied in higher vertebrates, this knowledge is very limited in fish. Therefore, in this study we have identified four prf genes in European sea bass (Dicentrarchus labrax) and evaluated their mRNA levels. All sea bass prf genes showed the typical and conserved domains of its human orthologue and were closely clustered by the phylogenetic analysis. In addition, all genes showed constitutive and ubiquitous tissular expression, being prf1.9 gene the most highly expressed in immune tissues. Subsequently, in vitro stimulation of head-kidney (HK) cells with phytohemagglutinin, a T-cell activator, showed an increase of all prf gene levels, except for prf1.3 gene. European sea bass HK cells increased the transcription of prf1.2 and prf1.9 during the innate cell-mediated cytotoxic activity against xenogeneic target cells. In addition, sea bass infected with nodavirus (NNV) showed a similar expression pattern of all prf in HK and brain at 15 days post-infection, except for prf1.3 gene and in the gonad. Finally, the use of a polyclonal antibody against PRF1.9 showed an increase of positive cells in HK, brain and gonad from NNV-infected fish. Taken together, the data seem to indicate that all prf genes, except prf1.3, appear to be involved in the European sea bass immunity, and probably in the cell-mediated cytotoxic response, with PRF1.9 playing the most important role against nodavirus. The involvement of the PRFs and the CMC activity in the vertical transmission success of the virus is also discussed.

The Streptococcus virulence protein PepO triggers anti-tumor immune responses by reprograming tumor-associated macrophages in a mouse triple negative breast cancer model

BackgroundThe efficacy of current surgery and chemotherapy for triple negative breast cancer (TNBC) is limited due to heterogenous and immunosuppressive tumor microenvironment (TME). Tumor associated macrophages (TAMs), which are regarded as an M2 tumor-promoting phenotype, are crucial in the development of the immunosuppressive TME. Targeting TAM reprograming is a promising strategy in anti-tumor therapy since reprogramming techniques provide the opportunity to actively enhance the antitumor immunological activity of TAM in addition to eliminating their tumor-supportive roles, which is rarely applied in TNBC clinically. However, how to drive M2 macrophages reprogramming into M1 with high potency remains a challenge and the molecular mechanisms how M2 macrophages polarized into M1 are poorly understood. Here, we identified a new immunoregulatory molecular PepO that was served as an immunoregulatory molecule governed the transformation of tumor-promoting M2 to tumor-inhibitory M1 cells and represented an effective anti-tumor property.ResultsAt the present study, we identified a new immunoregulatory molecular PepO, as a harmless immunoregulatory molecule, governed the transformation of tumor-promoting M2 to tumor-inhibitory M1 cells efficiently. PepO-primed M2 macrophages decreased the expression of tumor-supportive molecules like Arg-1, Tgfb, Vegfa and IL-10, and increased the expression of iNOS, Cxcl9, Cxcl10, TNF-α and IL-6 to inhibit TNBC growth. Moreover, PepO enhanced the functions of macrophages related to cell killing, phagocytosis and nitric oxide biosynthetic process, thereby inhibiting the development of tumors in vivo and in vitro. Mechanistically, PepO reprogramed TAMs toward M1 by activating PI3K-AKT-mTOR pathway via TLR4 and suppressed the function of M2 by inhibiting JAK2-STAT3 pathway via TLR2. The PI3K inhibitor LY294002 abrogated the role of PepO in switching M2 macrophages into M1 and in inhibiting TNBC growth in vivo. And PepO failed to govern the M2 macrophages to reprogram into M1 macrophages and inhibit TNBC when TLR2 or TLR4 was deficient. Moreover, PepO enhanced the antitumor activity of doxorubicin and the combination exerted a synergistic effect on TNBC suppression.ConclusionsOur research identified a possible macrophage-based TNBC immunotherapeutic approach and suggested a novel anticancer immunoregulatory molecular called PepO.

Reduction of Ca2+ Entry by a Specific Block of KCa3.1 Channels Optimizes Cytotoxic Activity of NK Cells against T-ALL Jurkat Cells.

Degranulation mediated killing mechanism by NK cells is dependent on store-operated Ca2+ entry (SOCE) and has optimum at moderate intracellular Ca2+ elevations so that partial block of SOCE optimizes the killing process. In this study, we tested the effect of the selective blocker of KCa3.1 channel NS6180 on SOCE and the killing efficiency of NK cells from healthy donors and NK-92 cells against T-ALL cell line Jurkat. Patch-clamp analysis showed that only one-quarter of resting NK cells functionally express KCa3.1 current, which increases 3-fold after activation by interleukins 15 and 2. Nevertheless, blockage of KCa3.1 significantly reduced SOCE and intracellular Ca2+ rise induced by IL-15 or target cell recognition. NS6180 (1 μM) decreased NK degranulation at zero time of coculture with Jurkat cells but already after 1 h, the degranulation reached the same level as in the control. Monitoring of target cell death by flow cytometry and confocal microscopy demonstrated that NS6180 significantly improved the killing ability of NK cells after 1 h in coculture with Jurkat cells and increased the Jurkat cell fraction with apoptotic and necrotic markers. Our data evidence a strong dependence of SOCE on KCa3.1 activity in NK cells and that KCa3.1 specific block can improve NK cytotoxicity.

Surrealism and the slaughterhouse: art and animals in Lotar’s La Villette and Franju’s Blood of the Beasts

In the sixth issue of Georges Bataille’s surrealist magazine Documents, published in 1929, a series of photographs by Eli Lotar documented an abattoir in the La Villette section of Paris. In text that accompanied the series, Bataille described the slaughterhouse as ‘a disturbing convergence of the mysteries of myth and the ominous grandeur typical of those places in which blood flows.’ The photographs chronicled both the banality and the horror of what took place in institutions that had removed the process of killing animals and processing their corpses from human view. Twenty years later, Georges Franju’s film Blood of the Beasts would provide its own exposure of the slaughterhouse, interspersed with quiet scenes of a Paris suburb, at the other end of the surrealist period. This project uses the two surrealist encounters with the slaughterhouse to evaluate the artistic movement’s interpretation of human society’s dependence on violence toward animals.

Mathematical model of killing an oil horizontal well

The physical picture of the killing fluid and the formation fluid movement in the process of killing a horizontal oil well has been described, a physical and mathematical model of the process has been developed and the limits of the model applicability have been indicated. It is recommended to conduct the killing process in two stages, separated by a technological break. During the first stage, the injected killing fluid fills the tubing, the annulus and the part of the horizontal wellbore. For the duration of the technological break, the denser tubing slowly displaces the formation fluid from the horizontal wellbore into the annulus where the formation fluid floats to the surface in the form of droplets. For the period of the second stage, the remaining amount of tubing is pumped into the well. The model is based on the well-known hydraulic equations for laminar flow of liquids, the solution of the flooded jet problem, as well as the model of one-dimensional vertical inertialess flow of a two-phase medium with incompressible phases. A closed system of equations has been formed taking into account the viscous friction losses on the walls of the horizontal pipe and at the interface between the formation fluid and the killing fluid flows. The solution of this system has been obtained and the values of the main process parameters have been found: velocities and flows of liquid gas and liquid coolant and time of complete replacement of liquid coolant by the killing fluid depending on the inclination angle of the horizontal pipe. It is shown that the character of the movement of the formation fluid drops in the pipe space depends on their volume fraction φ in the mixture with the killing fluid. With the value φ < 1/3 the jelly drops float up with a constant speed, while the jelly droplet radius and the speed of their floating up are unambiguously determined by the jelly stream size, density and viscosity of jelly and liquid hydrocarbon. The graphs of dependence of these parameters on the value of the formation fluid flow have been presented. On the basis of the research the recommendations for the process of killing horizontal oil wells have been formulated.

Effect of the killing style of individual CAR T cells on the clinicopathological behavior of therapeutic products in the clinic.

2548 Background: CAR T cell products that signal through CD28 and 41BB are highly effective against B lineage leukemia, despite exhibiting distinct efficacy and toxicity profiles in patients. Specifically, CD28 has been linked to higher upfront lytic activity and toxicity, while 41BB induces longer CAR T cell persistence and more durable progression free survival. We reasoned that the killing style of individual CAR T cells can explain the clinicopathological behavior of CAR T cell products in the clinic. Methods: We studied the cellular kinetics of CD28 and 41BB signaling CD19 CAR T cell products approved in the clinic, their single cell killing behavior in high throughput, the molecular composition of the lipid rafts inside the CAR immune synapse (CARIS) they form with their target cells, and their CARIS mechanical properties, then corroborated these findings in one kinetic model to explain their distinct clinicopathological behavior in the clinic. Results: We discovered that tumor encounter polarizes CD28 CAR T cell products to a predominance of more differentiated CD8 effectors that rely on short-lived highly lethal synapses with tumor cells. CD28 CAR T cell mediated synapses are characterized by fast mechanical buildup and resolution and brisk shuttling of CAR and other associated molecules into the CARIS and rapid polarization of the killing machinery in a manner that supports a mastery of serial killing mediated by perforin and granzymes. In contrast, 41BB responds to tumor stimulation by a Th2 -polarizing cytokine milieu that robustly expands a balanced CD4/CD8 population of effectors preserving a central memory phenotype. 41BB CAR T cells engage in lengthier synapses characterized by slower accumulation of CAR molecules in a mechanically tonic CARIS and rather collaborative yet lengthy Fas ligand-mediated killing process. Conclusions: We show here that CAR T cell signaling domains mediate distinct killing dynamics that can explain their behavior in patients. By understanding and potentially modulating these dynamics, the CAR T cell functionality and toxicity can be rationally optimized.

Removal of NOx using ozone injection and subsequent absorption in water

In nuclear reprocessing plant reduction of the nitric acid from the high level radioactive liquid waste is accomplished by the addition of formaldehyde. A significant amount NOx is generated during this conventional acid killing process. In this case NO oxidation followed by NO2 absorption is considered as a suitable option for NOx eradication, which also produces reusable nitric acid. Hence, investigations to explore the NO oxidation in the presence of O3 have been carried out for a relatively large system where the total flow rate of gas stream was 800 SLPM (52.4 m3/ h at 25 °C) and the concentration of NO was 480 ppm. It was observed that the concentration of NO decreases with the increase in the concentration of O3 added. A mathematical model has also been developed to predict the concentration of the gaseous components at the exit of the ozonization chamber. Model calculation shows that the reaction between NO and O3 is completed within fraction of a second. Further investigation on the absorption of NO2 in water was carried out by passing the exhaust gas through a scrubber. The absorption of NO2 in water leads to the formation of NO. An attempt has been made to enhance the performance of the water scrubber by injecting ozone into the gas phase during NO2 absorption. The model prediction reveals that N2O5 is the ultimate fate of the NO2 in the presence of O3. The evolution of N2O5 can be considered as two-step process. Reaction between NO2 and O3 is slow and the rate controlling step. On the contrary NO3 reacts quite rapidly with remaining NO2 and produces N2O5.

Differential effects of dexmedetomidine on Gram-positive and Gram-negative bacterial killing and phagocytosis

Dexmedetomidine is a commonly used sedative in perioperative and intensive care settings with purported immunomodulatory properties. Since its effects on immune functions against infections have not been extensively studied, we tested the effects of dexmedetomidine on Gram-positive [Staphylococcus aureus and Enterococcus faecalis] and Gram-negative bacteria [Escherichia coli], and on effector functions of human monocytes THP-1 cells against them. We evaluated phagocytosis, reactive oxygen species (ROS) formation, and CD11b activation, and performed RNA sequencing analyses. Our study revealed that dexmedetomidine improved Gram-positive but mitigated Gram-negative bacterial phagocytosis and killing in THP-1 cells. The attenuation of Toll-like receptor 4 (TLR4) signaling by dexmedetomidine was previously reported. Thus, we tested TLR4 inhibitor TAK242. Similar to dexmedetomidine, TAK242 reduced E. coli phagocytosis but enhanced CD11b activation. The reduced TLR4 response potentially increases CD11b activation and ROS generation and subsequently enhances Gram-positive bacterial killing. Conversely, dexmedetomidine may inhibit the TLR4-signaling pathway and mitigate the alternative phagocytosis pathway induced by TLR4 activation through LPS-mediated Gram-negative bacteria, resulting in worsened bacterial loads. We also examined another α2 adrenergic agonist, xylazine. Because xylazine did not affect bacterial clearance, we proposed that dexmedetomidine may have an off-target effect on bacterial killing process, potentially involving crosstalk between CD11b and TLR4. Despite its potential to attenuate inflammation, we provide a novel insight into potential risks of dexmedetomidine use during Gram-negative infections, highlighting the differential effect of dexmedetomidine on Gram-positive and Gram-negative bacteria.