This paper reported a case of acute severe nitrite poisoning with massive pulmonary thromboembolism (PTE), discussed the pathogenesis and summarized the treatment experience. Common symptoms of nitrite poisoning include headache, abdominal pain, shortness of breath, cyanosis, etc., which can be followed by encephalopathy, neurological dysfunction, hemolysis, etc. However, the cases of PTE are rare in clinical practice and are prone to missed diagnosis. Nitrite and methemoglobin may lead to vascular endothelial damage and promote thrombosis. In the diagnosis and treatment of acute severe nitrite poisoning patients, the targeted preventive measures should be taken.
本文报道急性重症亚硝酸盐中毒并发大面积肺血栓栓塞症（PTE）1例，结合文献探讨其发病机制，总结治疗经验。亚硝酸盐中毒常见症状包括头痛、腹痛、气促、紫绀等，可继发脑病、神经功能障碍、溶血等，而并发PTE的病例在临床中较为罕见，容易发生漏诊。亚硝酸盐、高铁血红蛋白可能导致血管内皮受损，促进血栓形成，对于急性重症亚硝酸盐中毒患者的诊治中应采取针对性预防措施。.

Extensive water and chemicals are used in the textile industry processes. Therefore, treatment of textile wastewater is vital to protect the environment, maintain the public health, and recover resources. However, due to poor operation and plant performance the partially treated textile wastewater was directly discharged to a nearby river. Thus, the aim of this study was to characterize the wastewater physicochemical properties and evaluate the performance of the textile factory-activated sludge process wastewater treatment plant (WWTP) in Bahir Dar, Ethiopia. In inlet and outlet of the WWTP, samples were collected for 6 months and analyzed on-site and in a laboratory for parameters including, dissolved oxygen, pH, temperature, total Kjeldhal nitrogen (TKN), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended solids (TSS), total nitrogen (TN), total phosphorous (TP), nitrite, nitrate, and metallic compounds. The TSS, BOD5, COD, TP, nitrite, ammonia, and total chromium result were above the discharge limit with 73.2 mg/L, 48.45 mg/L, 144.08 mg/L, 7.9 mg/L, 1.36 mg/L, 1.96 mg/L, and 0.16 mg/L, respectively. Multiple regression models were developed for each overall, net moving average, and instantaneous effluent quality index (EQI). The predictor parameters BOD5, TN, COD, TSS, and TP (R2 = 0.995 to 1.000) estimated the net pollution loads of all predictors as 492.55 kg/day and 655.44 kg/day. Except TN, TKN, and NO3, the remaining six performance parameters were violating the permissible limit daily. Furthermore, the overall plant efficiency was predicted as 38 % and 42 % for the moving average and instantaneous EQI, respectively. Our study concluded that the integrated regression models and EQI can easily estimate the plant efficiency and daily possible pollution load.

A patient with gunshots within inches of the skin developed intraoperative vasodilatory hypotension and methemoglobinemia, both recognized consequences of nitrite poisoning. A 1- mg/kg dose of methylene blue transiently and partially reversed methemoglobinemia, but the color of the methylene blue faded rapidly, consistent with bleaching of methylene blue by nitrite in vivo. Methylene blue did not raise blood pressure, consistent with inhibition of nitric oxide (NO) synthase. Because NO production from nitrite uses an NO synthase (NOS)-independent pathway, methylene blue is expected to have little effect on reversing hypotension from nitrite poisoning. Consider nitrite toxicity in gunshot patients with refractory vasodilatory hypotension and elevated methemoglobin.

Cyanosis is typically a sign of a potentially life-threatening condition in the emergency department and requires immediate workup and treatment. This case report highlights the diagnostic reasoning and clinical approach to cocaine- and volatile nitrite-induced methemoglobinemia (MHG). MHG is a rare, life-threatening cause of cyanosis. The diagnosis must be suspected in the emergency department in the presence of hypoxia and cyanosis disproportionate to cardiopulmonary repercussions and refractory to oxygen supplementation. Acquired causes are more prevalent than genetics, and recreational drugs should be highly suspected. Despite the rarity of this situation, cyanosis precipitants and the specificities of each hemoglobinopathy are reviewed in this article.

BACKGROUND: Methemoglobinemia is an excess of oxidized hemoglobin in the blood, affecting oxygen transportation. It is characterized by central cyanosis that does not respond to oxygen therapy. Prognosis is excellent when treated adequately and rapidly. We present a case report of a 38-year-old Caucasian man suffering from methemoglobinemia due to the use of poppers.
METHODS: A 38-year-old Caucasian man known as a smoker and addicted to cocaine was admitted to the emergency department with dyspnea, agitation, and central cyanosis that started approximately 3 hours before admission. The persistent hypoxia despite high-flow oxygen therapy and a history of poppers use helped to reveal a condition known as methemoglobinemia.
CONCLUSIONS: Our case highlighted a typical clinical presentation of methemoglobinemia. This possible life-threatening condition can occur after ingestion or inhalation of poppers, commonly sold in sex shops for recreational purposes. This can be easily confirmed by the methemoglobin level of the blood gases, provided the emergency physician considers this diagnosis. Rapid treatment with intravenous methylene blue is effective and leads to a favorable prognosis.

The removal of nitrogen compounds from a pretreated explosives wastewater in vertical flow constructed wetland planted with Vetiveria zizanioides (0.24 m2 × 0.70 m), filled with light expanded clay aggregates (Leca®NR 10/20), was studied. Experiments under constant hydraulic load, 50 ± 4 L m-2 d-1 and 83 ± 5 L m-2 d-1 without and with flooding level (25%), respectively, were made at different ammonium (3-48 mg NH4+-N L-1), nitrate (56-160 mg NO3--N L-1) and nitrite (0.3-1.1 mg NO2--N L-1) concentrations. Results indicate that without flooding level (unsaturated) the removal efficiencies obtained were 30 ± 9, 7 ± 1 and 96 ± 2%, respectively to NH4+-N, NO3--N and NO2--N. When using flooding level and an external carbon source (C/N ratio from 1.3 ± 0.19 to 2.5 ± 0.20), the organic matter (COD) removal efficiencies were above 90%, 75% for NH4+-N and 55% to NO3--N. Increasing the C/N ratio from 2.9 ± 0.21 to 4 ± 0.22 did not contributed to upgrade the efficiencies of COD, NH4+-N and NO3--N removal. The denitrification process was occurred in aerobic conditions and nitrite production have ben occurred, probably due to the presence of aerobic conditions that inhibited partially denitrification.

The recently developed multiple structures from one crystal (MSOX) serial crystallography method can be used to provide multiple snapshots of the progress of enzymatic reactions taking place within a protein crystal. Such MSOX snapshots can be used as a reference for combined quantum mechanical/molecular mechanical (QM/MM) simulations of enzyme reactivity within the crystal. QM/MM calculations are used to identify details of reference states that cannot be directly observed by X-ray diffraction experiments, such as protonation and oxidation states. These reference states are then used as known fixed endpoints for the modeling of reaction paths. We investigate the mechanism of nitrite reduction in an Achromobacter cycloclastes copper nitrite reductase crystal using MSOX-guided QM/MM calculations, identifying the change in nitrite binding orientation with a change in copper oxidation state, and determining the reaction path to the final NO-bound MSOX structure. The results are compared with QM/MM simulations performed in a solvated environment.

OBJECTIVE: The gross error of the assigned value-classical statistical method was developed that all participants in proficiency testing activities could obtain unbiased evaluation in case of a low number of participants(& lt; 17).
METHODS: This developed method was employed to evaluate the testing result of nitrite-N and lead in water from participants along the \"Belt and Road\", which was organized by CNCA in 2019.
RESULTS: Use the specified value gross error-classical statistical method to evaluate the feedback result of 29(15+14) participants with non-normal distribution, 4 out of 15 participants in \"Lead in Water\" get a \"unsatisfied\", 5 out of the 14 participants in \"Nitrite in Water(as Nitrogen)\"get a \"unsatisfactory\".
CONCLUSIONS: When the robust statistics and classical statistical method are unable to make objective evaluations respectively, this method could mildly remove outliers and avoid the extreme evaluation of \"all satisfied\"or \"all dissatisfied\", which truly reflected the real ability of each participant and could be applied to the proficiency testing activity with low number of participants.

Developing photoelectrochemical (PEC) sensors based on photocatalytic materials has recently attracted great interest as an emerging technology for environmental monitoring. TiO2 P25 is a well-known highly active photocatalyst, cheap, and produced commercially on a large scale. In the current work, a practical and durable TiO2-based PEC sensor has been fabricated by immobilizing TiO2 P25 nanoparticles at disposable screen-printed carbon substrates using drop-casting method. The fabricated PEC sensor has been applied for the anodic-detection and determination of nitrite (NO2-) ions under UV(A) light (LED, 365 nm) using chronoamperometry (CA) and differential pulse voltammetry (DPV). Linear calibration curves were obtained between the photocurrent responses and the concentrations of NO2- ions in the ranges of 0.1-5.0 and 0.5-10 mg L-1 for CA and DPV, respectively. Surprisingly, the detection limits (sensitivities) of the fabricated sensor towards NO2- ions under light were enhanced by a factor of 4.75 (4.1) and 8.3 (37.4) for CA and DPV, respectively, in comparsion with those measured in the dark. It is found that the photo-excitation of TiO2 facilitates the photooxidation of NO2- ions via the photo-generated holes whereas the photogenerated electrons contribute to the enhanced photocurrent and consequently the enhanced detection limit and sensitivity. The fabricated TiO2-based PEC sensor exhibits a good stability, durability, and satisfying selectivity for NO2- ions determination. These results indicate that the TiO2-based PEC sensor fabricated by utilizing cheap and commercially available components has great potential for being transferred from lab-to-factory.

Sulphide is one of the inhibitors in the nitrification process in WWTP in regions with sulphate rich soils. As little information is currently available on sulphide nitrification inhibition, the aim of this study was to develop a method based on a modification of the Successive Additions Method to calibrate the effect of sulphide on the activity of ammonia-oxidising bacteria (AOB) and nitrite-oxidising bacteria (NOB). The developed method was then applied to activated sludge samples from two WWTPs with different influent sulphide concentrations. In both cases, sulphide had a greater inhibitory effect on NOB than AOB activity. The sulphide inhibition was found to be lower in the activated sludge fed with sulphide-rich wastewater. The AOB and NOB activity measured at different sulphide concentrations could be accurately modelled with the Hill inhibition equation.