Long-term storage protocol of reagent red blood cells treated with 0.01M dithiothreitol (DTT) for pre-transfusion testing of patients receiving anti-CD38 therapy, daratumumab

OBJECTIVE

Use red blood cell stabilizer to store the antibody screening and antibody identification reagent red blood cells (RBCs) treated with 0.01 mol/L DTT and investigate its value in the pre-transfusion examinations of patients treated with daratumumab.

METHOD

Determined the optimal incubation time for the 0.01 mol/L DTT-treated RBCs method by evaluating the effect of treatment at different time points. Added ID-CellStab to store DTT-treated RBCs, determined the maximum shelf life of reagent RBCs by monitoring the hemolysis index, and assessed changes in the antigenicity of blood group antigens on the surface of RBCs during storage with antibody reagents.

RESULT

A protocol for long-term storage of reagent red blood cells treated with the 0.01 mol/L DTT method was established. The optimal incubation time was 40-50 min. RBCs could be stored stably for 18 days after adding ID-CellStab. The protocol was able to eliminate pan-agglutination caused by daratumumab, with no significant changes in the antigens of most blood group systems, except for some attenuation of K antigen and Duffy blood group system antigens during the storage period.

CONCLUSION

The storage protocol of reagent RBCs based on the 0.01 mol/L DTT method does not affect the detection of most blood group antibodies and retains a certain degree of detection ability for anti-K antibodies, allowing patients treated with daratumumab to quickly perform pre-transfusion examinations, making up for the shortcomings of currently commercial reagent RBCs.

[Application of Modified DTT Methods to Reduce the Interference of Daratumumab on Serological Detection]

OBJECTIVE

To modified the classic dithiothreitol (DTT) method for treating red blood cells (RBCs) in Technical Manual of American Association of Blood Banks（AABB） and evaluate its application value in pre-transfusion examination of patients treated with daratumumab.

METHODS

The classic 0.2 mol/L DTT method was improved in terms of PBS, DTT concentration, donor RBCs concentration (suspended/packed) and sample processing time. The modified DTT methods and AABB classic DTT method were applied to the blood matching tests of 12 multiple myeloma patients treated with daratumumab. The effect of treating panel RBCs with modified DTT methods on the detection of other irregular antibodies was evaluated by using antiserum and antibody reagents with known antibody properties.

RESULTS

Two modified DTT methods were established (method 1: changed the concentration of DTT to 0.01 mol/L; method 2: changed the concentration of DTT to 0.02 mol/L and replaced the packed RBCs with 3% RBCs suspension). The optimal treatment time was 35 min for the modified DTT methods. At this time, the pan-agglutination caused by daratumumab was eliminated, but the detection of antibodies such as anti-E, anti-JKa, anti-M were not affected, and the titer of anti-K antibodies was only slightly decreased.

CONCLUSION

The modified DTT methods were effective, which can eliminate the interference of daratumumab while retaining the activity of the Kell blood group system, and can replace the current classic DTT method in AABB Technical Manual.

Single hormone or synthetic agonist induces Gs/Gi coupling selectivity of EP receptors via distinct binding modes and propagating paths

To accomplish concerted physiological reactions, nature has diversified functions of a single hormone at at least two primary levels: 1) Different receptors recognize the same hormone, and 2) different cellular effectors couple to the same hormone-receptor pair [R.P. Xiao, Sci STKE 2001, re15 (2001); L. Hein, J. D. Altman, B.K. Kobilka, Nature 402, 181-184 (1999); Y. Daaka, L. M. Luttrell, R. J. Lefkowitz, Nature 390, 88-91 (1997)]. Not only these questions lie in the heart of hormone actions and receptor signaling but also dissecting mechanisms underlying these questions could offer therapeutic routes for refractory diseases, such as kidney injury (KI) or X-linked nephrogenic diabetes insipidus (NDI). Here, we identified that Gs-biased signaling, but not Gi activation downstream of EP4, showed beneficial effects for both KI and NDI treatments. Notably, by solving Cryo-electron microscope (cryo-EM) structures of EP3-Gi, EP4-Gs, and EP4-Gi in complex with endogenous prostaglandin E2 (PGE2)or two synthetic agonists and comparing with PGE2-EP2-Gs structures, we found that unique primary sequences of prostaglandin E2 receptor (EP) receptors and distinct conformational states of the EP4 ligand pocket govern the Gs/Gi transducer coupling selectivity through different structural propagation paths, especially via TM6 and TM7, to generate selective cytoplasmic structural features. In particular, the orientation of the PGE2 ω-chain and two distinct pockets encompassing agonist L902688 of EP4 were differentiated by their Gs/Gi coupling ability. Further, we identified common and distinct features of cytoplasmic side of EP receptors for Gs/Gi coupling and provide a structural basis for selective and biased agonist design of EP4 with therapeutic potential.

Fate of selenium in a Se-enriched region of North China: Translocation, bioaccumulation, source, and health benefits

There are limited studies on the translocation and bioaccumulation of selenium (Se) in weak alkaline cultivated Se-enriched soil, and the sources and speciation of Se in wheat grains remain unclear. In this study, we measured the Se levels in soils, roots, stems, and wheat grains from Se-enriched cultivated land in Ci County, China, which has a high incidence of esophageal cancer. The Se levels in the roots were higher than those in the soils, indicating that wheat plants bioaccumulated high concentrations of Se from the soil (enrichment coefficient [EC] range from the soil to the root: 0.94-3.29). Redundancy analysis indicated that the bioaccumulated factor, translocation coefficient, and EC were mainly controlled by phosphorus, pH, and Fe₂O₃ (contribution rates: 37.5%, 19.5%, and 15.9%, respectively). Linear regression analysis revealed that the sources of Se in grains were mainly from the water-soluble fraction (R² = 0.55, at p < 0.05), the weakly acidic fraction (R² = 0.84, at p < 0.05), the reducible fraction (R² = 0.84, at p < 0.05), and the oxidizable fraction (R² = 0.70, at p < 0.05), as well as from atmospheric deposition (R² = 0.37, at p < 0.01). There is a significant correlation between the Se from atmospheric deposition and the oxidizable fraction (R² = 0.62, at p < 0.01) and the residual fraction (R² = 0.33, at p < 0.01). The contribution of Se input flux from atmospheric deposition was 5.50 g/hm² for one year. Furthermore, the average content of organic Se in wheat grains was 58.93%. The Se concentrations found in wheat grains were considered beneficial for human health based on a comparison with the Chinese Society of Nutrition standard and worldwide levels. The results of this study will increase the overall knowledge on the theme, which could help prevent and control the harmful effects of undesirable concentrations of Se on human health.

[Related factors of negative conversion time of nucleic acid in children with COVID-19]

Objective: To explore the related factors of negative conversion time (NCT) of nucleic acid in children with COVID-19. Methods: A retrospective cohort study was conducted. A total of 225 children who were diagnosed with COVID-19 and admitted to Changxing Branch of Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine from April 3^rd to May 31^st 2022 were enrolled in the study. The infection age, gender, viral load, basic disease, clinical symptoms and information of accompanying caregivers were retrospectively analyzed. According to age, the children were divided into<3 years of age group and 3-<18 years of age group. According to the viral nucleic acid test results, the children were divided into positive accompanying caregiver group and negative accompanying caregiver group. Comparisons between groups were performed using Mann-Whitney U test or Chi-square test. Multivariate Logistic regression analysis was used to analyze the related factors of NCT of nucleic acid in children with COVID-19. Results: Among the 225 patients (120 boys and 105 girls) of age 2.8 (1.3, 6.2) years, 119 children <3 years and 106 children 3-<18 years of age, 19 cases were diagnosed with moderate COVID-19, and the other 206 cases were diagnosed with mild COVID-19. There were 141 patients in the positive accompanying caregiver group and 84 patients in the negative accompanying caregiver group.Patients 3-<18 years of age had a shorter NCT (5 (3, 7) vs.7 (4, 9) d, Z=-4.17, P<0.001) compared with patients <3 years of age. Patients in the negative accompanying caregiver group had a shorter NCT (5 (3, 7) vs.6 (4, 9) d,Z=-2.89,P=0.004) compared with patients in the positive accompanying caregiver group. Multivariate Logistic regression analysis showed that anorexia was associated with NCT of nucleic acid (OR=3.74,95%CI 1.69-8.31, P=0.001). Conclusion: Accompanying caregiver with positive nucleic acid test may prolong NCT of nucleic acid, and decreased appetite may be associated with prolonged NCT of nucleic acid in children with COVID-19.

Dietary Total Antioxidant Capacity and Cognitive Function in Older Adults in the United States: The NHANES 2011-2014

OBJECTIVES

Oxidative stress level takes part in the development of cognitive decline. However, the association between total antioxidant capacity (TAC) from diet and cognitive function is controversial. The aim of this study was to investigate the relationship between TAC and the cognitive function of older adults in the U.S.

DESIGN

A cross-sectional study.

SETTING

National Health and Nutrition Examination Surveys database.

PARTICIPANTS

2712 older adults aged over 60 years.

MEASUREMENTS

TAC was calculated from 8 antioxidative vitamins based on the reference values for vitamin C equivalent antioxidant capacity obtained from individuals' 24 h dietary recall. Four memory-related assessments were employed [Immediate Recall test (IRT), Delayed Recall test (DRT), Animal Fluency test (AFT), and Digit Symbol Substitution test (DSST)].

RESULTS

Among the 2712 participants, the median age was 68 years, and 50.4% were women. Participants in the group with higher TAC levels had relatively higher IRT, AFT and DSST scores (P=0.025, P=0.008, P<0.001, respectively). In adjusted weighted linear regression, log-transformed TAC was positively associated with AFT (β=1.10, 95%CI: 0.51, 1.70) and DSST (β=2.81, 95%CI: 1.16, 4.45). Compared with the first quartile, the participants in the second (Q2 vs. Q1, OR=0.66, 95%CI: 0.43,1.02) and fourth quartile (Q4 vs. Q1, OR=0.47, 95%CI:0.28, 0.78) of log-transformed TAC showed a decreased risk of impaired cognitive function (ICF) after adjusting for confounders. The dose-response analysis indicated a gradual descent in the risk of ICF as TAC increases. Diabetes mellitus (DM) mediated part of the effect of TAC on ICF. The relationship between TAC and ICF was more pronounced in subjects with DM (Q4 vs Q1, OR=0.36, 95%CI:0.17, 0.74).

CONCLUSION

Our findings support that higher dietary antioxidant potential was related to a decreased risk of cognitive dysfunction, particularly in the subjects with DM who may have oxidative injury. DM was one of the factors mediating the effect of TAC on ICF.

Association of metabolic syndrome with cardiovascular outcomes in hypertensive patients: a systematic review and meta-analysis

PURPOSE

The association between metabolic syndrome (MetS) and cardiovascular outcomes in patients with hypertension is still controversial. This meta-analysis sought to evaluate the association of MetS with cardiovascular outcomes in hypertensive patients.

METHODS

Two authors comprehensively searched PubMed and Embase databases from their inception to April 18, 2020 for the longitudinal studies that evaluated the association of MetS with cardiovascular outcomes in patients with hypertension. The main outcomes were major adverse cardiovascular events (myocardial infarction, revascularization, stroke, hospitalization due to heart failure, etc.) and stroke.

RESULTS

Eight studies consisting of 36,614 hypertensive patients were identified and analyzed. Meta-analysis indicated that MetS was associated with an increased risk of major adverse cardiovascular events (risk ratio [RR] 1.55; 95% confidence intervals [CI] 1.28-1.87), cardiovascular mortality (RR 1.44; 95%CI 1.13-1.82), and stroke (RR 1.46; 95%CI 1.22-1.75), respectively. Sensitivity analysis further confirmed the robustness of the prognostic value of MetS.

CONCLUSIONS

MetS is associated with higher risk of major adverse cardiovascular events, cardiovascular mortality, and stroke in patients with hypertension. Determination of MetS may contribute to improving cardiovascular risk stratification in hypertension.

In vitro assays on the susceptibility of four species of nematophagous fungi to anthelmintics and chemical fungicides/antifungal drug

Using nematophagous fungi for the biological control of animal parasitic nematodes will become one of the most promising strategies in the search for alternative chemical drugs. The purpose of this study was to check the in vitro activity of four anthelmintics, four chemical fungicides and two antifungal drugs on the spore germination of nematophagous fungi: Duddingtonia flagrans (SF170), Arthrobotrys oligospora (447), Arthrobotrys superba (435) and Arthrobotrys sp. (PS011). A modified 24-well cell culture plate assay was conducted to evaluate the susceptibility of nematophagous fungi against drugs tested by calculating the effective middle concentrations (EC₅₀ ) of each tested drug to inhibit the germination of fungal spores. EC₅₀ ranged between 0·7 and 47·2 μg ml^-1 for fenbendazole, thiabendazole and ivermectin, except levamisole (546·5-4057·8 μg ml^-1 ). EC₅₀ of tested fungicides was 0·6-2·3 μg ml^-1 for carbendazim, 55·9-247·4 μg ml^-1 for metalaxyl, 24·4-45·2 μg ml^-1 for difenoconazole, and 555·9-1438·3 μg ml^-1 for pentachloronitrobenzene (PCNB). EC₅₀ of two antifungal drugs was 0·03-3·4 μg ml^-1 for amphotericin B and 0·3-10·9 μg ml^-1 for ketoconazole. The results showed that 10 tested drugs, except for levamisole and PCNB, had in vitro inhibitory effects on nematophagous fungi. The chlamydospores of D. flagrans had the highest sensitivity to nine tested drugs, except for ketoconazole.

Anti-JMH alloantibody in inherited JMH-negative patients leads to immunogenic destruction of JMH-positive RBCs

The clinical significance of the specific anti-John Milton Hagen (JMH) alloantibody in inherited JMH-negative patients remains unclear. During clinical blood transfusion, it is often classified as an anti-JMH autoantibody in acquired JMH-negative patients, which might further lead to the occurrence of haemolysis events. In this study, we found that the proportion of inherited JMH-negative people in the Guangzhou population was 0.41%, based on the study of 243 blood samples by flow cytometry. Gene sequencing analysis revealed two novel variants located in exon 11 (c.1348G>A, p.Ala449Thr) and exon 14 (c.1989G>T, p.Leu663Phe). Specific antigen presentation showed that JMH-positive RBCs (red blood cells) could be internalized by SEMA7A^-/- dendritic cells (DCs) and that SEMA7A^-/- DCs activated by the semaphorin 7a (Sema7a) protein or JMH-positive erythrocytes further induced activation of CD4⁺ T cells to secrete interferon (IFN)-γ. Transfusion of JMH-positive RBCs could lead to the production of the specific anti-JMH alloantibody in Sema7a knock-out (KO) C57 mice. After erythrocyte sensitization, complement C3 was specifically fixed, causing the destruction of JMH-positive erythrocytes. The anti-JMH alloantibody caused immunological destruction of JMH-positive erythrocytes and promoted the clearance of JMH-positive RBCs. We should be cautious when making conclusions about the clinical significance of the anti-JMH alloantibody.

Long noncoding RNA DLX6-AS1 functions as a competing endogenous RNA for miR-577 to promote malignant development of colorectal cancer

OBJECTIVE

Recent researches have proved that long noncoding RNAs (lncRNAs) play essential roles in tumorigenesis. The aim of this study was to investigate the exact role of lncRNA DLX6-AS1 in the development of colorectal cancer (CRC), and to explore the possible mechanism.

PATIENTS AND METHODS

DLX6-AS1 expression in CRC tissues was detected by Real Time-quantitative Polymerase Chain Reaction (RT-qPCR). Function assays were conducted to detect the effect of DLX6-AS1 on the proliferation and metastasis of CRC in vitro. Furthermore, luciferase reporter gene assay and RNA immunoprecipitation assay (RIP) were used to explore the underlying mechanism of DLX6-AS1.

RESULTS

DLX6-AS1 expression in CRC samples was significantly higher than that of adjacent tissues. Loss of DLX6-AS1 markedly inhibited the proliferation, migration, and invasion of CRC cells. Furthermore, luciferase reporter gene assay and RIP assay showed that DLX6-AS1 acted as a competing endogenous RNA via sponging miR-577 in CRC.

CONCLUSIONS

DLX6-AS1 could promote the proliferation, migration, and invasion of CRC by sponging miR-577, which might offer a potential therapeutic target for CRC.

Long noncoding RNA DLX6-AS1 functions as a competing endogenous RNA for miR-577 to promote malignant development of colorectal cancer

Since this article has been suspected of research misconduct and the corresponding authors did not respond to our request to prove originality of data and figures, "Long noncoding RNA DLX6-AS1 functions as a competing endogenous RNA for miR-577 to promote malignant development of colorectal cancer, by F.-R. Zhou, Z.-P. Pan, F. Shen, L.-Q. Huang, J.-H. Cui, K. Cai, X.-L. Guo, published in Eur Rev Med Pharmacol Sci 2019; 23 (9): 3742-3748-DOI: 10.26355/eurrev_201905_17800-PMID: 31115000" has been withdrawn. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/17800.

Coronavirus disease 2019: A new severe acute respiratory syndrome from Wuhan in China

An outbreak of new severe acute respiratory syndrome coronavirus disease, coronavirus disease 2019 (COVID-19), has emerged during December 2019. The ongoing outbreak in Wuhan City spread rapidly throughout China, where the fatality rate ranged from 2.1 to 4.9%. Due to its high transmissibility, the World Health Organization (WHO) declared a public health emergency of international concern on 30 January 2020. The current outbreak has the potential to become the first pandemic of the new millennium. Most patients who were first diagnosed with COVID-19 worked at or lived in the vicinity of the local Huanan Seafood Wholesale  Market, where live animals were also on sale. The concerted efforts of Chinese scientists led to the independent isolation from patients and identification of a novel coronavirus, SARS coronavirus 2 (SARS-CoV-2), on 6 January 2020; this has been an important step in the development of treatment. The purpose of this article is to overview the history, epidemiology, clinical characteristics, diagnosis, and treatment of COVID 2019 reported in recently published studies. Based on the results of virus genome sequencing and a model of the interaction between host cells and the virus, we propose several possible targets for antiviral drugs, which may provide new ideas for epidemic control and vaccine development. Keywords: 2019 novel coronavirus; pneumonia; SARS-CoV-2; Coronaviridae; COVID-19.

Multiple-centre clinical evaluation of an ultrafast single-tube assay for SARS-CoV-2 RNA

OBJECTIVE

To evaluate the performance of an ultrafast single-tube nucleic acid isothermal amplification detection assay for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA using clinical samples from multiple centres.

METHODS

A reverse transcription recombinase-aided amplification (RT-RAA) assay for SARS-CoV-2 was conducted within 15 minutes at 39°C with portable instruments after addition of extracted RNA. The clinical performance of RT-RAA assay was evaluated using 947 clinical samples from five institutions in four regions of China; approved commercial fluorescence quantitative real-time PCR (qRT-PCR) kits were used for parallel detection. The sensitivity and specificity of RT-RAA were compared and analysed.

RESULTS

The RT-RAA test results of 926 samples were consistent with those of qRT-PCR (330 were positive, 596 negative); 21 results were inconsistent. The sensitivity and specificity of RT-RAA was 97.63% (330/338, 95% confidence interval (CI) 95.21 to 98.90) and 97.87% (596/609, 95% CI 96.28 to 98.81) respectively. The positive and negative predictive values were 96.21% (330/343, 95% CI 93.45 to 97.88) and 98.68% (596/604, 95% CI 97.30 to 99.38) respectively. The total coincidence rate was 97.78% (926/947, 95% CI 96.80 to 98.70), and the kappa was 0.952 (p < 0.05).

CONCLUSIONS

With comparable sensitivity and specificity to the commercial qRT-PCR kits, RT-RAA assay for SARS-CoV-2 exhibited the distinctive advantages of simplicity and rapidity in terms of operation and turnaround time.

Cycling and total risks of multiple As fractions in the Beijing-Tianjin-Hebei area on the agricultural plain, China

The high toxicity of As can cause serious health risks for humans; therefore, understanding the behavior of As in weakly alkaline soil conditions relevant to agricultural plains is important. To investigate the mobility and total risks of multiple fractions of As, 230 pairs of soil (including soil cores) and, wheat grain, and corresponding groundwater samples and 38 atmospheric deposition samples were collected from agricultural soil in the Beijing-Tianjin-Hebei region, China, which is a typical wheat-growing area. Seven fractions of As, namely, water-soluble (As1), exchangeable (As2), carbonate-bound (As3), humic acid-bound (As4), Fe-Mn oxide-bound (As5), organic matter-bound (As6), and residual (As7) As, were analyzed using a sequential extraction procedure to better understand and confirm the relationship among these different forms. Correlation and principal components analyses showed a significant relationship among As1-As5, and As in atmospheric deposits and As in groundwater and soil samples showed a positive relationship. As found in wheat, therefore, mainly originated from the soil and atmospheric deposits, and indirectly from the groundwater. As in the soil samples was mainly controlled by Mn and Fe₂O₃ based on the vertical distribution of soil cores and correlation analysis. The health risk assessments showed that As in the multiple fractions did not form a potential non-cancer risk for children and adults. However, residents could still face the risk of developing cancer by ingesting wheat and drinking the groundwater. The findings of this study have important implications for understanding the hydrological/geochemical behavior of As and the soil and water quality in a wide range of environmental settings. Additionally, our findings provided arguments for decreasing the concentrations of As in the wheat production system and to remind residents to decrease ingestion of their staple food (wheat) and drink less of the local groundwater.

Analysis of the Spatial Distribution Characteristics of Urban Resilience and Its Influencing Factors: A Case Study of 56 Cities in China

The healthy development of the city has received widespread attention in the world, and urban resilience is an important issue in the study of urban development. In order to better provide a useful reference for urban resilience and urban health development, this paper takes 56 cities in China as the research object, and selects 29 indicators from urban infrastructure, economy, ecology and society. The combination weight method, exploratory spatial data analysis (ESDA) and spatial measurement model are used to explore the spatial distribution of urban resilience and its influencing factors. From 2006 to 2017, the urban resilience of prefecture-level cities in the four provinces showed a wave-like rise. During the study period, the urban resilience values, measured as Moran's Is, were greater than 0.3300, showing a significantly positive correlation in regard to their spatial distribution. Regarding the local spatial correlation, the urban resilience of the study area had spatial agglomeration characteristics within the province, with a significant distribution of "cold hot spots" in the spatial distribution. From the perspective of the factors that affected urban resilience, the proportion of the actual use of foreign capital in GDP and carbon emissions per 10,000 CNY of GDP had a negative impact and GDP per square kilometer, the proportion of urban pension insurance coverage, the proportion of the population with higher education, and expenditure to maintain and build cities had a positive impact. The development strategy of urban resilience must be combined with the actual situation of the region, and the rational resilience performance evaluation system and the top-level design of urban resilience improvement should be formulated to comprehensively improve urban resilience.

Street Dust Heavy Metal Pollution Source Apportionment and Sustainable Management in A Typical City-Shijiazhuang, China

Street dust is repeatedly raised by the wind as a secondary suspension, helping heavy metals therein to enter the human body through the respiratory system, harming human health. A detailed investigation was conducted to determine levels and sources of Cd (cadmium), Cr (chromium), Cu (copper), Pb (lead), Zn (zinc), Ni (nick), and Hg (mercury) contamination in street dust from Shijiazhuang, China. The average concentrations of these metals were: Cd, 1.86 mg·kg⁻¹; Cr, 131.7 mg·kg⁻¹; Ni, 40.99 mg·kg⁻¹; Cu, 91.06 mg·kg⁻¹; Pb, 154.78 mg·kg⁻¹, Hg, 0.29 mg·kg⁻¹; and Zn, 496.17 mg·kg⁻¹—all of which were greater than the local soil reference values. The concentrations of the heavy metals were mapped for the three Shijiazhuang ring roads, with the results showing significant differences between each ring. Application of enrichment factors and geoaccumulation indexes showed that there was significant enrichment and accumulation of Cd, Pb, Zn, and Hg. Multivariate statistical analyses showed that Cd, Pb, Zn, and Hg levels were mainly controlled by human activities, while Cr, Ni, and Cu levels were associated with natural sources. Absolute principal component scores with multiple linear regression (APCS-MLR) were applied to facilitate source apportionment. The results showed that the mixed (traffic and industry) group contributed 53.55%, 59.7%, and 62.25% of the Cd, Pb, and Zn concentration, respectively, while the natural sources group contributed 58.01%, 65.09%, and 66.91% of the Cu, Ni, and Cr concentration, respectively. The burning coal group was found to be responsible for 63.38% of the Hg present in the samples. These results provide a useful theoretical basis for Shijiazhuang authorities to address heavy metal pollution management.