NOx Levels Research Articles

Benfloreks: Dost mu, Düşman mı? Deneysel Diyabette, Benfloreksin Beyindeki Oksidatif Olaylara Etkileri

Benfluorex is a pharmacological agent with antidiabetic and antihyperlipidemic properties. In this study, the brain's oxidative and non-enzymatic antioxidant status in diabetic and benfluorex administrated diabetic rats have been investigated. For the experimental procedures, three groups of 18 Wistar albino rats were used as the control, diabetes (induced by streptozotocin), and benfluorex treated diabetic rats (benfluorex administration intragastric 50 mg/kg daily for 21 days). Brain NOx, TBARS, GSH, AA levels, and MPO activity were determined spectrophotometrically. Benfluorex administration was caused that decreased lipid peroxidation and MPO activity while increased non-enzymatic antioxidant and NOx levels. These results showed that benfluorex treatment positively affects lipid peroxidation and non-enzymatic antioxidant status of the brain during diabetes.

Evaluation of the relationship between intravascular hemolysis and clinical manifestations in sickle cell disease: decreased hemopexin during vaso-occlusive crises and increased inflammation in acute chest syndrome.

The aims of this study were to determine the possible relationships between the levels of hemin, hemopexin, acid sphingomyelinase, nitrite/nitrate (NOx), and other parameters in patients with SCD and to assess whether they were associated with vaso-occlusive crises (VOCs) or acute chest syndrome (ACS). Patients with SCD (homozygous or sickle beta-thalassemia) who were confirmed to have VOC or ACS were included. Blood samples were obtained at admission, on the third day of hospitalization, and at steady state. Demographic characteristics, pain (visual analog scale), complication history, complete blood count, lactate dehydrogenase, and C-reactive protein levels were recorded. Hemin, hemopexin, acid sphingomyelinase, and NOx were measured via ELISA. A total of 31 patients (22 VOC, 9 ACS) were included. Mean age was 16.4 ± 4.7years. Admission white blood cell count and C-reactive protein levels were significantly higher in the ACS group. Patients with ACS also demonstrated a significant decreasing trend of LDH and an increasing trend of NOx values from admission to steady state. Notably, hemopexin levels were significantly lower on the third day of hospitalization compared to steady-state levels. Despite limited patient count in the ACS group, these patients appear to have strikingly greater inflammatory activation at admission, and the progression of ACS may be associated with LDH and NOx levels. Lower hemopexin levels during hospitalization versus steady state appear to support a role for the administration of hemopexin therapy during crises.

A potential diagnostic serum immunological marker panel to differentiate between primary and secondary knee osteoarthritis.

Inflammation contributes to knee osteoarthritis (KOA) where many immunological mediators participate in its initiation and progression. Most clinicians manage primary (pKOA) and secondary osteoarthritis (sKOA) alike. Whether immunological profiles of pKOA and sKOA differ remains obscure. Hence, we aimed to differentially identify potential serum immunologic diagnostic markers of pKOA and of sKOA. This case control study used 46 KOA patients (pKOA, n = 30; sKOA, n = 16), and 60 age, gender matched controls (normal healthy, n = 30; systemic lupus erythematosus [SLE] disease controls, n = 30) where serum was assayed for cytokines (TNF-α, IL-1β, IL-6, IL-10) and nitric oxide derivatives (NOx). Sandwich ELISA assessed cytokine levels, while the 'Griess assay' quantified NOx levels. The diagnostic accuracy of optimal marker combinations was evaluated by the CombiROC web tool. Compared with pKOA, sKOA serum displayed significantly elevated levels of pro inflammatory cytokines (TNF-α, IL-1β, IL-6) with a concurrent decrease in the anti-inflammatory cytokine, IL-10 (P<0.05). This was reiterated by significantly higher Th1:Th2 (TNF-α: IL-10) serum cytokine ratio observed in sKOA compared to that of pKOA. The CombiROC curves identified TNF-α, IL-1β, IL-6 and NOx as the best performing panel of potential diagnostic markers to discriminate pKOA from control groups (~97% accuracy, 90% Sensitivity [SE] and 98% specificity [SP]), while TNF-α, IL-1β and IL-6 discriminated sKOA from control groups (~100% accuracy, 100% SE, and 98% SP). The study identified discrete serum immune biomarker panels to differentiate between pKOA (TNF-α, IL-1β, IL-6 and NOx) and sKOA (TNF-α, IL-1β and IL-6). These findings may assist in developing distinct therapeutic agents for the two types of KOA.

Influence of biodiesel blends produced in Colombia on a Diesel engine

Diesel engines have dominated the heavy duty and passenger vehicle market in the past 30 years. Consequently, the oil-derived fuels demand and the amount of pollutant emissions have witnessed exponential growth during the last three decades. Although Diesel engines present the advantage of higher efficiency and, therefore, lower levels of CO2 emissions, they produce high levels of NOX and particulate matter. In order to face these difficulties, the use of alternative fuels started booming in the early 2000s and continue to gain influence today. Biodiesel stands out from the alternative fuels’ selection for its ease of use, production, storage and potential to reduce levels of particles, CO, HC and CO2. The main goal of this research is to experimentally determine the influence of palm oil biodiesel produced in Colombia on a Diesel engine’s behavior in terms of engine performance and pollutant emissions. As different mixtures of commercial Diesel and biodiesel at different operating conditions were tested, the results showed that it is possible to maintain the engine’s performance at acceptable levels and to, in some cases, reduce smoke density and NOX levels.

Evolution of Atmospheric Total Organic Carbon from Petrochemical Mixtures.

Reactive organic compounds play a central role in the formation of ozone and secondary organic aerosols. The ability to accurately predict their fate, in part, relies upon quantitative knowledge of the chemical and physical parameters associated with the total organic carbon (TOC), which includes both precursors and oxidation products that evolve in the atmosphere over short to long time scales. However, such knowledge, obtained via limited carbon closure experiments, has not been attained for complex anthropogenic emissions. Here we present the first comprehensive characterization of TOC in the atmospheric oxidation of organic vapors from light and heavy oil mixtures associated with oil sand operations. Despite the complexity of the investigated oil mixtures, we are able to achieve carbon closure (83-116%) within the uncertainties (±20%), with the degree of the closure being dependent upon the vapor composition and NOx levels. In contrast to biogenic precursors (e.g., α-pinene), the photochemical time scale required for a largely complete oxidation and evolution of chemical parameters is very long for the petrochemical vapors (i.e., ∼7-10 days vs ∼1 day), likely due to the lower initial precursor reactivity. This suggests that petrochemical emissions and their impacts are likely to extend further spatially than biogenic emissions, and retain more of their complex composition and reactivity for many days. The results of this work provide key parameters to regional models for further improving the representation of the chemical evolution of petrochemical emissions.

Heterogeneity and chemical reactivity of the remote troposphere defined by aircraft measurements

Abstract. The NASA Atmospheric Tomography (ATom) mission built a photochemical climatology of air parcels based on in situ measurements with the NASA DC-8 aircraft along objectively planned profiling transects through the middle of the Pacific and Atlantic oceans. In this paper we present and analyze a data set of 10 s (2 km) merged and gap-filled observations of the key reactive species driving the chemical budgets of O3 and CH4 (O3, CH4, CO, H2O, HCHO, H2O2, CH3OOH, C2H6, higher alkanes, alkenes, aromatics, NOx, HNO3, HNO4, peroxyacetyl nitrate, other organic nitrates), consisting of 146 494 distinct air parcels from ATom deployments 1 through 4. Six models calculated the O3 and CH4 photochemical tendencies from this modeling data stream for ATom 1. We find that 80 %–90 % of the total reactivity lies in the top 50 % of the parcels and 25 %–35 % in the top 10 %, supporting previous model-only studies that tropospheric chemistry is driven by a fraction of all the air. In other words, accurate simulation of the least reactive 50 % of the troposphere is unimportant for global budgets. Surprisingly, the probability densities of species and reactivities averaged on a model scale (100 km) differ only slightly from the 2 km ATom data, indicating that much of the heterogeneity in tropospheric chemistry can be captured with current global chemistry models. Comparing the ATom reactivities over the tropical oceans with climatological statistics from six global chemistry models, we find excellent agreement with the loss of O3 and CH4 but sharp disagreement with production of O3. The models sharply underestimate O3 production below 4 km in both Pacific and Atlantic basins, and this can be traced to lower NOx levels than observed. Attaching photochemical reactivities to measurements of chemical species allows for a richer, yet more constrained-to-what-matters, set of metrics for model evaluation.

Стан судинного ендотелію у пацієнтів з хронічними запальними захворюваннями кишечника i різним нутритивним статусом

Актуальність. Визначення ендотеліальної функції за допомогою неінвазивних методів відіграє основну роль у прогнозуваннi перебігу різних захворювань, ризику розвитку ускладнень та оцінцi лікування. Мета: оцінка ендотеліальної функції в пацієнтів iз хронічними запальними захворюваннями кишечника (ХЗЗК) залежно від їхнього нутритивного статусу шляхом визначення стану судинного ендотелію в пробі з реактивною гіперемією та вмісту метаболітів оксиду азоту (МОА) в сироватці крові. Матеріали та методи. Сто двадцять пацієнтів iз ХЗЗК (81 — iз неспецифічним виразковим колітом (НВК) та 39 пацієнтів із хворобою Крона (ХК)) були розподілені на групи залежно від антропометричних характеристик: І — зі зниженим нутритивним статусом (n = 70); ІІ — iз нормальним (n = 20); ІІІ — iз підвищеним нутритивним статусом (n = 30). У сироватці крові пацієнтів вимірювали рівень МОА за В.А. Метельською. Для оцінки ендотеліальної функції визначали ендотелійзалежну вазодилатацію плечової артерії в пробі з реактивною гіперемією. Результати. На основі проведених досліджень встановлено вірогідне зниження вмісту МОА в сироватці крові: у пацієнтів iз НВК — у 1,7 раза (р &lt; 0,01) та з ХК — в 1,9 раза (р &lt; 0,001). Зниження вмісту МОА в сироватці крові не залежало від нутритивного статусу пацієнтів iз ХЗЗК. Порушення функції судинного ендотелію виявлено в 76,7 % випадків: зниження функції ендотелію — у 49,2 %, дисфункція — у 27,5 %. Зміни функції судинного ендотелію зареєстровано в 75,7 % пацієнтів І групи, 75 % — ІІ та у 83,4 % пацієнтів ІІІ групи, переважно внаслiдок зниження функції ендотелію. Висновки. Показано, що в 71 % пацієнтів iз ХЗЗК відбувається вірогідне зниження вмісту МОА в сироватці крові, що не залежить від їхнього нутритивного статусу. У хворих iз НВК спостерігалися більш виражені зміни у частотi виявлених порушень та більш значне зростання діаметра плечової артерії порівняно iз пацієнтами з ХК. Зниження нутритивного статусу супроводжувалося змінами функції судинного ендотелію в 75,4 % випадків.

Early detection of lean blowout in a combustor using symbolic analysis of colour images

Recently, lean combustion has been accepted as one of the preferable modes to run both small and large scale energy sectors as it reduces the level of NOx (oxides of nitrogen) emissions. However, ultra-lean combustion is more susceptible to lean blowout (LBO) which significantly reduces engine life and operating reliability. Therefore, early detection of LBO is important so that operator can get sufficient lead time to initiate precautionary actions. The current investigation proposes a novel technique based on the conversion of flame colour matrix into symbolic strings. The generation of symbolic strings is done based on the partitioning of the hue space obtained from transformation of RGB (Red-Green-Blue) to HSV (Hue-Saturation-Value) using uniform partitioning method. The partitions are determined at the reference state and kept fixed for other equivalence ratios (anomalous or non-reference states). Thus, the hue value at each pixel of the image is assigned a symbol depending on its belonging to a particular partition. Thereafter, an array of symbolic state probability vector at reference combustion state is determined based on the probability of pixel hue value being in a particular symbolic state or symbol (number of symbolic states is considered as 8). Also, for other anomalous or non-reference combustion states, symbolic state probability vectors are estimated using the partition formed at the reference state. The difference in symbolic state probability vectors between reference and anomalous combustion states gives the anomaly measure, which is used here to detect the flame blowout. The early increasing trend of anomaly towards the blowout for both premixed and partially premixed flames indicate that the measure can be helpful to detect the approach towards LBO. The estimation of anomaly is shown for using the flame images of different quantities. The random selection of five images from a flame video shows to be very effective in capturing the trend of anomaly which also ensures low computational effort. Thus, the tool based on symbolic colour image analysis (SCIA) may also be helpful in the mitigation of LBO.

Impact of public transport strikes on traffic and pollution in the city of Barcelona

• Metro and RENFE strikes increase air pollution. • Air pollution is slightly affected by bus strikes. • Effects on pollution are larger for public transports with no direct substitutes. • Metro and RENFE commuters switch to private cars when there is a strike. • FGC users switch to non-pollutant transports during strikes. Many Spanish cities’ air contains excessive levels of pollutants caused by traffic. These pollutants are associated with high concentrations of vehicles in urban and surrounding areas, such as Madrid and Barcelona. According to the World Health Organization (WHO), 96.8% of Spain's population breathe polluted air. This paper provides empirical evidence on the effect of public transport strikes on Barcelona’s air quality through an econometric analysis. The period analyzed included 147 days of some kind of public transport strike: bus (57), metro (21), trains (71), and tram (4); and also four general strikes. The estimates show that public transport strikes increases the concentration level of SO2, CO, PM 10 , and NOX throughout the city, especially in the case of metro and RENFE trains. These results also allow us to understand how commuters substitute transport modes and to propose specific policies to increase public transport use.

Nitrogen oxides (NO and NO2) pollution in the Accra metropolis: Spatiotemporal patterns and the role of meteorology

Economic and urban development in sub-Saharan Africa (SSA) may be shifting the dominant air pollution sources in cities from biomass to road traffic. Considered as a marker for traffic-related air pollution in cities, we conducted a city-wide measurement of NOx levels in the Accra Metropolis and examined their spatiotemporal patterns in relation to land use and meteorological factors. Between April 2019 to June 2020, we collected weekly integrated NOx (n = 428) and NO2 (n = 472) samples at 10 fixed (year-long) and 124 rotating (week-long) sites. Data from the same time of year were compared to a previous study (2006) to assess changes in NO2 concentrations. NO and NO2 concentrations were highest in commercial/business/industrial (66 and 76 μg/m3, respectively) and high-density residential areas (47 and 59 μg/m3, respectively), compared with peri-urban locations. We observed annual means of 68 and 70 μg/m3 for NO and NO2, and a clear seasonal variation, with the mean NO2 of 63 μg/m3 (non-Harmattan) increased by 25–56% to 87 μg/m3 (Harmattan) across different site types. The NO2/NOx ratio was also elevated by 19–28%. Both NO and NO2 levels were associated with indicators of road traffic emissions (e.g. distance to major roads), but not with community biomass use (e.g. wood and charcoal). We found strong correlations between both NO2 and NO2/NOx and mixing layer depth, incident solar radiation and water vapor mixing ratio. These findings represent an increase of 25–180% when compared to a small study conducted in two high-density residential neighborhoods in Accra in 2006. Road traffic may be replacing community biomass use (major source of fine particulate matter) as the prominent source of air pollution in Accra, with policy implication for growing cities in SSA.

Ultra-low PCDD/F emissions and their particle size and mass distribution in a hazardous waste treatment system

An integrated gasification-flameless combustion-melting process was approached by a twin-cyclonic flow in a hazardous waste thermal treatment plant. A series of advanced scrubber, cyclonic demister, activated carbon adsorption, and baghouse processes were equipped for the end-of-pipe treatment. The untreated filterable particulate matter, CO, and NOx levels were only 283, 47.1, and 15.9 mg/Nm3, indicating the flameless combustion inhibited their formation by narrowing the post-combustion zone. The filterable particle mass-size distribution was equally contributed by nucleation, accumulation, and coarse formations, while their number concentration was predominated by nucleation (99.6%). That could enhance the adsorption of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) on ultrafine particles. Both total mass and toxic equivalent concentrations of PCDD/Fs were reduced 99.9% by the new air pollution control system when a slight reformation occurred during scrubbing. However, the escaped PCDD/Fs were mainly distributed on the ultrafine particles, which should be further inhibited by either increasing their sizes or equipping backup filtrations. Finally, the new process concentrates the PCDD/Fs into the scrubbing sludge, which could be recirculated back into the thermal process. This study not only reveals the emission risk of the ultrafine particle-bound PCDD/Fs, but also provides an effective process to remove them for industrial application.

Experimental and Kinetic Modeling Study of 3-Methyl-2-butenol (Prenol) Oxidation

Longer chain alcohols with 4–5 carbon atoms are attractive alternative fuels as they can be derived from biological sources and since their combustion leads to lower exhaust gas levels of NOx and soot compared to commercial fossil fuels. The auto-ignition behavior of fuels that contain both a hydroxyl group and a C═C double bond in their molecular structure is not well established in the literature. Understanding the influence of these functional groups on the ignition behavior of fuels is critical in the development of tailor-made fuels for advanced combustion engines. In this study, ignition delay times of an unsaturated alcohol, 3-methyl-2-butenol (prenol), are measured using a high-pressure shock tube and a rapid compression machine at pressures of 15 and 30 bar at equivalence ratios of 0.5, 1.0, and 2.0 in “air” in the temperature range 600–1400 K. A detailed kinetic model is developed and validated using the new experimental data in this study. In addition, speciation data in a jet-stirred reactor, ignition delay times, and laminar burning velocities available in the literature were also used to validate the new kinetic model. Fuel flux and sensitivity analyses are performed using this new model to determine the important fuel consumption pathways and critical reactions that affect the reactivity of prenol.

PM emissions - assessment of combustion energy transfer with Schizochytrium sp. algal biodiesel and blends in IC engine

The continuous growing demand for fossil fuel puts an enormous pressure on finding a better replacement. This research paper explores the detailed information on the improved production, emission and performance characteristics of the distinct bio-oil derived from the micro algae of Schizochytrium. The algae were grown in the artificial seawater with enough nitrogen supply at the required standard conditions. The lipid growth and production of the bio-oil were monitored closely and measured. Different fuel blends were used at different concentrations as B0 (100% Diesel), B10 (10% schizochytrium biofuel +90% diesel), B20 (20% schizochytrium biofuel +80% diesel) and B30 (30% schizochytrium biofuel +70% diesel). A small single cylinder, four stroke diesel engine was used to conduct the tests. All tests were conducted at different speed conditions of 1200 rpm to 2100 rpm in six intervals. The performance qualities of bio-oil such as CO, NOX, and smoke and CO2 emission along with the performance qualities of brake thermal efficiency and brake specific fuel consumption. Form the results, the Schizochytrium microalgae bio-oil as the bio fuel for diesel engines in the moderate level showed the improved performance by increasing the BTE and reducing the harmful gas emissions except NOX. However, the emission level of NOX was slightly higher than the diesel emitted value. The difference between them was negligible.

Prophylactic effect of myricetin and apigenin against lipopolysaccharide-induced acute liver injury.

Liver has an important role in the initiation and progression of multiple organ failure that occurs in sepsis. Many natural active substances can be used to reduce the liver injury caused by sepsis. For this aim, the effects of myricetin and apigenin on mice model of acute liver injury was evaluated in this study. Thirty-six mice were randomly divided into six groups as; control, lipopolysaccharide (LPS) (5mg/kg), LPS + myricetin (100mg/kg), LPS + myricetin (200mg/kg), LPS + apigenin (100mg/kg), and LPS + apigenin (200mg/kg) groups. Myricetin and apigenin were administered orally for 7days, and LPS was administered intraperitoneally only on the 7th day of the study. 24h after LPS application, all animals were sacrificed and serum biochemical parameters, histopathology and oxidative stress and inflammation markers of liver tissue were examined. Myricetin and apigenin pre-treatments increased serum albumin and total protein levels, liver GSH level and catalase and SOD activities and decreased serum ALT, AST, ALP, γ-GT, CRP, total and direct bilirubin levels, liver MPO activity, MDA, NOx, PGE2, TNF-α, IL-1β, and IL-6 levels, iNOS and COX-2 mRNA levels, phosphorylation of NF-κB p65, IκB, and IKK proteins but not p38, ERK, and JNK proteins in LPS-treated mice. Myricetin and apigenin administration also regained the hepatic architecture disrupted during LPS application. Myricetin and apigenin pre-treatments led to reduction of liver injury indices and oxidative stress and inflammatory events and these flavonoids has probably hepatoprotective effects in acute liver injury.

N-Methyl-D-aspartate Glutamate Receptor Modulates Cardiovascular and Neuroendocrine Responses Evoked by Hemorrhagic Shock in Rats.

Here, we report the participation of N-methyl-D-aspartate (NMDA) glutamate receptor in the mediation of cardiovascular and circulating vasopressin responses evoked by a hemorrhagic stimulus. In addition, once NMDA receptor activation is a prominent mechanism involved in nitric oxide (NO) synthesis in the brain, we investigated whether control of hemorrhagic shock by NMDA glutamate receptor was followed by changes in NO synthesis in brain supramedullary structures involved in cardiovascular and neuroendocrine control. Thus, we observed that intraperitoneal administration of the selective NMDA glutamate receptor antagonist dizocilpine maleate (MK801, 0.3 mg/kg) delayed and reduced the magnitude of hemorrhage-induced hypotension. Besides, hemorrhage induced a tachycardia response in the posthemorrhage period (i.e., recovery period) in control animals, and systemic treatment with MK801 caused a bradycardia response during hemorrhagic shock. Hemorrhagic stimulus increased plasma vasopressin levels during the recovery period and NMDA receptor antagonism increased concentration of this hormone during both the hemorrhage and postbleeding periods in relation to control animals. Moreover, hemorrhagic shock caused a decrease in NOx levels in the paraventricular nucleus of the hypothalamus (PVN), amygdala, bed nucleus of the stria terminalis (BNST), and ventral periaqueductal gray matter (vPAG). Nevertheless, treatment with MK801 did not affect these effects. Taken together, these results indicate that the NMDA glutamate receptor is involved in the hemorrhagic shock by inhibiting circulating vasopressin release. Our data also suggest a role of the NMDA receptor in tachycardia, but not in the decreased NO synthesis in the brain evoked by hemorrhage.

Highly oxygenated organic molecules produced by the oxidation of benzene and toluene in a wide range of OH exposure and NO&amp;lt;sub&amp;gt;&amp;lt;i&amp;gt;x&amp;lt;/i&amp;gt;&amp;lt;/sub&amp;gt; conditions

Abstract. Oxidation of aromatic volatile organic compounds (VOCs) leads to the formation of tropospheric ozone and secondary organic aerosol, for which gaseous oxygenated products are important intermediates. We show, herein, the experimental results of highly oxygenated organic molecules (HOMs) produced by the oxidation of benzene and toluene in a wide range of OH exposure and NOx conditions. The results suggest that multigeneration OH oxidation plays an important role in the product distribution, which likely proceeds more preferably via H subtraction than OH addition for early generation products from light aromatics. More oxygenated products present in our study than in previous flow tube studies, highlighting the impact of experimental conditions on product distributions. The formation of dimeric products, however, was suppressed and might be unfavorable under conditions of high OH exposure and low NOx in toluene oxidation. Under high-NOx conditions, nitrogen-containing multifunctional products are formed, while the formation of other HOMs is suppressed. Products containing two nitrogen atoms become more important as the NOx level increases, and the concentrations of these compounds depend significantly on NO2. The highly oxygenated nitrogen-containing products might be peroxyacyl nitrates, implying a prolonged effective lifetime of RO2 that facilitates regional pollution. Our results call for further investigation on the roles of high-NO2 conditions in the oxidation of aromatic VOCs.

Changes in the concentration and composition of urban aerosols during the COVID-19 lockdown

This work investigates the impact of COVID-19 restrictive measures on the mass concentrations of PM1 and PM10, and their chemical components (water-soluble ions, organic and elemental carbon, and major and trace metals) at an urban site in the western Mediterranean. The evolution of gaseous pollutants (NOx, O3 and some volatile organic compounds) was also analyzed. The concentrations measured during the lockdown in 2020 were compared to those obtained during the same period over the preceding five years. The average decrease in the levels of NOx and traffic-related volatile organic compounds was higher than 50 %, while O3 concentrations did not exhibit significant variations during the study period. Our results show that temporal variations in PM1 and PM10 concentrations were strongly affected by the frequency of Saharan dust events. When these episodes were excluded from the analysis period, a 35 % decrease in PM1 and PM10 levels was observed. Traffic restrictions during the lockdown led to important reductions in the concentrations of elemental carbon and metals derived from road dust (e.g. Ca and Fe) and break wear (e.g. Cu). Regarding secondary inorganic aerosols, nitrate showed the largest reductions as a consequence of the drop in local emissions of NOx.

A Study on Serum Nitric Oxide and Hydrogen Sulfide in Essential Hypertension Cases in a Tertiary Care Hospital in West Bengal

Background-Essential hypertension is a multifactorial disease of unknown etiology characterized by a chronic elevation of blood pressure without any secondary causes. Nitric oxide and hydrogen sulfide are vasodilatory gasotransmitters whose deficiency results in endothelial dysfunction and vasoconstriction and hence is one of the etiological factors in the development of hypertension. Aims and Objectives – The study aimed to estimate the serum levels of NO and H₂S and to find out their correlation in essential hypertension cases and normotensive controls. Materials and Methods- Serum levels of NO and H₂S were measured using chemical methods, in fifty patients with essential hypertension and compared with fifty age-matched controls. Results- The mean serum NOx level in essential hypertension cases is 45.45 ± 11.09 µmol/L which is significantly lower (p-value &lt;0.001) than that of controls where it is 166.40 ± 16.63 µmol / L. The mean serum H₂S level in essential hypertension cases is 45.61 ± 11.01 µmol/ L which is again significantly lower ( p-value &lt;0.001) than controls in which it is 111.54 ± 9.60 µmol/ L. A statistically significant positive correlation exists between serum NOx and H₂S levels in overall study subjects. Conclusion- This study demonstrates that both the serum levels of NO and H₂S decrease with an increase in BP in essential hypertension cases. There exists a positive correlation between NO and H₂S in overall study subjects. Thus, the simultaneous decline in bioavailability of both NO and H₂S is a significant underlying cause in the development of essential hypertension.

Removing NOx Pollution by Photocatalytic Building Materials in Real- Life: Evaluation of Existing Field Studies

The NOx gasses (NO and NO2) are among the most important air pollutants due to the toxicity of NO2, as well as the role of NOx in the tropospheric oxidation of Volatile Organic Carbons (VOCs), contributing to the formation of other hazardous air pollutants. Air pollution is one of the biggest health threats worldwide; hence reducing NOx levels is an important objective of the UN sustainable development goals, e.g., #3, “Good health and well-being” and #11 “Sustainable cities and communities.”Photocatalysis using TiO2 and light is a promising technique for removing NOx along with other pollutants, as demonstrated on a laboratory scale. Furthermore, a long-range of real-life test studies of varying scales have been conducted during the past two decades. The results of these studies have been conflicting, with some studies reporting no effect on the ambient air quality and others reporting significant reductions of NOx levels. However, the studies are very difficult to compare and assess due to the different approaches used, which consequently vary in quality. In this review, we aim to develop a set of objective evaluation criteria to assess the quality of the individual studies in order to simplify the interpretation and comparison of the existing studies. Moreover, we propose some guidelines for future test studies. Furthermore, the approaches and main conclusion from 23 studies are independently assessed and discussed herein.

Atmospheric Impacts of COVID-19 on NOx and VOC Levels over China Based on TROPOMI and IASI Satellite Data and Modeling

China was the first country to undergo large-scale lockdowns in response to the pandemic in early 2020 and a progressive return to normalization after April 2020. Spaceborne observations of atmospheric nitrogen dioxide (NO2) and oxygenated volatile organic compounds (OVOCs), including formaldehyde (HCHO), glyoxal (CHOCHO), and peroxyacetyl nitrate (PAN), reveal important changes over China in 2020, relative to 2019, in response to the pandemic-induced shutdown and the subsequent drop in pollutant emissions. In February, at the peak of the shutdown, the observed declines in OVOC levels were generally weaker (less than 20%) compared to the observed NO2 reductions (−40%). In May 2020, the observations reveal moderate decreases in NO2 (−15%) and PAN (−21%), small changes in CHOCHO (−3%) and HCHO (6%). Model simulations using the regional model MAGRITTEv1.1 with anthropogenic emissions accounting for the reductions due to the pandemic explain to a large extent the observed changes in lockdown-affected regions. The model results suggest that meteorological variability accounts for a minor but non-negligible part (~−5%) of the observed changes for NO2, whereas it is negligible for CHOCHO but plays a more substantial role for HCHO and PAN, especially in May. The interannual variability of biogenic and biomass burning emissions also contribute to the observed variations, explaining e.g., the important column increases of NO2 and OVOCs in February 2020, relative to 2019. These changes are well captured by the model simulations.