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2.
BMC Nurs ; 23(1): 145, 2024 Mar 01.
Article in English | MEDLINE | ID: mdl-38429747

ABSTRACT

BACKGROUND: It is pertinent to understand the perceptions of healthcare workers (HCWs) with their associated personal protective equipment (PPE) usage and heat strain symptoms experienced to effectively combat the negative effects of heat stress during treatment and care activities. METHODS: We evaluated the associated heat stress perceived by HCWs across Asia and validated a questionnaire on perceptions of heat stress, associated PPE usage, and heat strain symptoms experienced. The questionnaire was administered to 3,082 HCWs in six Asian regions. Factor analyses, including Cronbach's alpha, assessed the questionnaire's validity and reliability. Structural equation modelling analysed the effects of knowledge, attitudes and practices, and heat strain symptoms. RESULTS: The questionnaire was found to be reliable in assessing HCWs' knowledge, and attitudes and practices towards heat stress and PPE usage (both Cronbach's alpha = 0.9), but not heat strain symptoms (Cronbach's alpha = 0.6). Despite knowledge of heat stress, HCWs had negative attitudes and practices regarding PPE usage (ß1 = 0.6, p < 0.001). Knowledge (path coefficient = 0.2, p < 0.001), and negative attitudes and practices (path coefficient = 0.2, p < 0.001) of HCWs towards heat stress and PPE usage adversely affected symptoms experienced. CONCLUSIONS: The questionnaire was not reliable in assessing symptoms. HCWs should, nevertheless, still self-assess their symptoms for early detection of heat strain. To effectively attenuate heat strain, understanding HCWs' attitudes and practices towards PPE usage should guide policymakers in implementing targeted heat management strategies.

3.
Healthcare (Basel) ; 12(4)2024 Feb 08.
Article in English | MEDLINE | ID: mdl-38391808

ABSTRACT

Background: The grassroots healthcare system is the closest and most community-oriented force, working as an extended arm of the primary healthcare network to implement healthcare programs at the household level. Its comprehensive development is a crucial task set by the Vietnamese government. Job satisfaction significantly influences the performance of healthcare staff within this system. Objective: to assess job satisfaction among healthcare staff using the short-form of the Minnesota Satisfaction Questionnaire while also evaluating the Vietnamese translation of this scale. Methods: A descriptive cross-sectional study with analysis based on the responses of 587 healthcare staff using the Vietnamese-translated version of the MSQ short-form scale. The response data from the participants were subjected to CFA, and if the proposed CFA model did not fit the data, EFA was conducted. Results: The results indicate that the new model, which evaluates job-related factors in three distinct groups, is more suitable than the original model. The 14 questions of the MSQ scale were analyzed and categorized into Autonomy, Obligation, and Specificity based on the participants' responses. The confirmatory factor analysis (CFA) conducted on the new model demonstrated favorable fit indices: CFI = 0.934, TLI = 0.917, GFI = 0.919, and RMSEA = 0.093 (90% CI: 0.085-0.102). Conclusions: The Vietnamese version of the MSQ short form demonstrates reliability and validity. It also provides additional data on the effectiveness of the MSQ short form in measuring job satisfaction.

4.
Per Med ; 20(6): 467-475, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37937420

ABSTRACT

Background: Noninvasive prenatal tests for monogenic diseases (NIPT-SGG) have recently been reported as helpful in early-stage antenatal screening. Our study describes the clinical and genetic features of cases identified by NIPT-SGG. Materials & methods: In a cohort pregnancy with abnormal sonograms, affected cases were confirmed by invasive diagnostic tests concurrently, with NIPT-SGG targeting 25 common dominant single-gene diseases. Results: A total of 13 single-gene fetuses were confirmed, including Noonan and Costello syndromes, thanatophoric dysplasia, achondroplasia, osteogenesis imperfecta and Apert syndrome. Two novel variants seen were tuberous sclerosis complex (TSC2 c.4154G>A) and Alagille syndrome (JAG1 c.3452del). Conclusion: NIPT-SGG and standard tests agree on the results for 13 fetuses with monogenic disorders. This panel method of screening can benefit high-risk Vietnamese pregnancies, but further research is encouraged to expand on the causative gene panel.


Subject(s)
Prenatal Diagnosis , Thanatophoric Dysplasia , Pregnancy , Female , Humans , Vietnam , Thanatophoric Dysplasia/diagnosis , Thanatophoric Dysplasia/genetics , Receptor, Fibroblast Growth Factor, Type 3
5.
J Am Chem Soc ; 145(41): 22442-22455, 2023 Oct 18.
Article in English | MEDLINE | ID: mdl-37791901

ABSTRACT

In 2015, we reported a photochemical method for directed C-C bond cleavage/radical fluorination of relatively unstrained cyclic acetals using Selectfluor and catalytic 9-fluorenone. Herein, we provide a detailed mechanistic study of this reaction, during which it was discovered that the key electron transfer step proceeds through substrate oxidation from a Selectfluor-derived N-centered radical intermediate (rather than through initially suspected photoinduced electron transfer). This finding led to proof of concept for two new methodologies, demonstrating that unstrained C-C bond fluorination can also be achieved under chemical and electrochemical conditions. Moreover, as C-C and C-H bond fluorination reactions are both theoretically possible on 2-aryl-cycloalkanone acetals and would involve the same reactive intermediate, we studied the competition between single-electron transfer (SET) and apparent hydrogen-atom transfer (HAT) pathways in acetal fluorination reactions using density functional theory. Finally, these analyses were applied more broadly to other classes of C-H and C-C bond fluorination reactions developed over the past decade, addressing the feasibility of SET processes masquerading as HAT in C-H fluorination literature.

6.
Org Lett ; 25(23): 4318-4322, 2023 Jun 16.
Article in English | MEDLINE | ID: mdl-37279142

ABSTRACT

We have found that face-to-face π-stacked aromatic rings show the propensity to activate one another toward electrophilic aromatic substitution through direct influence of the probe aromatic ring by the adjacent stacked ring, rather than through the formation of relay or "sandwich complexes." This activation remains in force even when one of the rings is deactivated through nitration. The resulting dinitrated products are shown to crystallize in an extended parallel offset stacked form, in stark contrast to the substrate.

7.
J Pediatr Pharmacol Ther ; 28(3): 212-221, 2023.
Article in English | MEDLINE | ID: mdl-37303771

ABSTRACT

OBJECTIVE: To evaluate a pharmacist-led intervention's effectiveness in reducing drug-related problems (DRPs ( related to prescriptions for pediatric outpatients. METHODS: We conducted a randomized controlled trial. We recruited and randomly assigned 31 physicians to control or intervention groups. We collected 775 prescriptions (375 from the control group and 400 from the intervention group) at the start. For 3 weeks, intervention physicians received additional information and meetings with pharmacists in addition to the usual practices of the hospital. We then collected prescriptions at the end of the study. We classified DRPs, based on reliable references (Supplemental Table S1) at baseline and endpoint (a week after the intervention). The primary outcome was the proportion of prescriptions with DRPs, and secondary outcomes were the proportions of prescriptions with specific DRP types. RESULTS: The influence of the intervention on general DRPs and specific DRPs was the study's main finding. The pharmacist-led intervention helped reduce the prescriptions with DRPs proportion in the intervention group to 41.0%, compared with 49.3% in the control group (p < 0.05). The DRPs proportion related to the timing of administration relative to meals, unlike the other DRP types, increased in the control group (from 31.7% to 34.9%) and decreased in the intervention group (from 31.3% to 25.3%), with a significant difference between the 2 groups at endpoint (p < 0.01). Patients aged >2 to ≤6 years (OR, 1.871; 95% CI, 1.340-2.613) and receiving ≥5 drugs (OR, 5.037; 95% CI, 2.472-10.261) were at greater risk of experiencing DRPs related to prescribing. CONCLUSIONS: A pharmacist-led intervention improved DRP occurrence related to physicians' prescribing. Pharmacists could be involved in in-depth research with physicians in the prescribing process to provide tailored interventions.

8.
Heliyon ; 9(2): e13487, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36816254

ABSTRACT

Content marketing is becoming an important trend in the tourism industry and is attracting the attention of many stakeholders. Previous studies have sporadically highlighted only some content marketing aspects, but none comprehensively described the topic. To fill this gap, this study adopts a comprehensive approach by combining two bibliometric co-citation and co-keyword analysis methods of 659 articles on content marketing in travel sectors. The co-citation results indicate that tourism content marketing research has been concentrated on the themes of (1) the impact of electronic word of mouth (eWOM) and word of mouth (WOM) on business performance; (2) the role of social media, user-generated content (UGC) and destination image formulation; (3) the impact of eWOM and UGC on the decision-making process; as well as (4) opportunities and challenges. Additionally, based on the co-keyword analysis, hot research topics are explored, including online review implementation; UGC implementation; communication and information search; customer behavior prediction model; the decision-making process; and issues related to user experience, quality, and management. Among these, UGC implementation is the most likely trend that researchers can develop in the future. In addition, the influence of other types of UGC (e.g., user-generated travel videos) is a promising avenue for future research. This study will help researchers understand the role and influence of tourism content marketing. Furthermore, tourism marketers can use content marketing to restore destination image and address last-minute booking issues after the COVID-19 pandemic.

9.
Chemosphere ; 309(Pt 1): 136605, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36179921

ABSTRACT

Constructed wetlands (CWs) are a cost-effective technology for wastewater treatment in which plant-microorganism relationships play a key role in transforming pollutants. However, there is little knowledge about the spatial organization of microbial metabolic processes in CWs. Here we show the structuring of microbial transformation of inorganic sulfur compounds (ISCs) in two horizontal subsurface-flow CW models fed with sulfate-rich artificial wastewater. One model was fully planted with Juncus effusus, while the other was planted only in the middle to investigate further the influence of the plant on ISC transformations. Chemical analyses revealed that sulfate reduction and re-oxidation of sulfide/sulfur occurred simultaneously along the flow paths, with net reduction at the beginning of the CWs, where organic carbon from the influent was still present, and predominant re-oxidation in the downstream sections. Porewater ISC concentrations hardly differed between the two CWs. However, analysis of the bacterial communities showed that sulfur cycling in the fully planted CW was much higher. Total bacterial abundances were about 50 times and 3-4 orders of magnitude higher in the rhizoplane than in porewater and on gravel, respectively, as quantified by qPCR determination of the 16S rRNA gene. Sequencing of 16S rRNA gene amplicons revealed that bacterial communities on the roots and in the porewater differed substantially, apparently a consequence of the fluxes of oxygen and exudates from the roots. Furthermore, we observed partitioning of ISC transforming bacteria into different niches of the CWs. The results of the chemical and microbial analyses collectively support that extensive sulfur cycling occurred in the rhizospheres of the CW models. The study is relevant to the treatment of sulfur-containing wastewater and the elucidation of microbial communities involved in biogeochemical activities to improve water quality.


Subject(s)
Environmental Pollutants , Wetlands , Wastewater/chemistry , RNA, Ribosomal, 16S/genetics , Sulfur/metabolism , Sulfates , Carbon/metabolism , Plants/metabolism , Bacteria/genetics , Bacteria/metabolism , Oxygen , Sulfides , Waste Disposal, Fluid/methods
10.
Sci Total Environ ; 852: 158203, 2022 Dec 15.
Article in English | MEDLINE | ID: mdl-36044953

ABSTRACT

Sulfur (S) is a crucial component in the environment and living organisms. This work is the first attempt to provide an overview and critical discussion on the roles, mechanisms, and environmental applications of sulfur-oxidizing bacteria (SOB). The findings reveal that key enzymes of SOB embarked on oxidation of sulfide, sulfite, thiosulfate, and elemental S. Conversion of reduced S compounds was oxidatively catalyzed by various enzymes (e.g. sulfide: quinone oxidoreductase, flavocytochrome c-sulfide dehydrogenase, dissimilatory sulfite reductase, heterodisulfide reductase-like proteins). Environmental applications of SOB discussed include detoxifying hydrogen sulfide, soil bioremediation, and wastewater treatment. SOB producing S0 engaged in biological S soil amendments (e.g. saline-alkali soil remediation, the oxidation of sulfide-bearing minerals). Biotreatment of H2S using SOB occurred under both aerobic and anaerobic conditions. Sulfide, nitrate, and sulfamethoxazole were removed through SOB suspension cultures and S0-based carriers. Finally, this work presented future perspectives on SOB development, including S0 recovery, SOB enrichment, field measurement and identification of sulfur compounds, and the development of mathematical simulation.


Subject(s)
Hydrogen Sulfide , Biodegradation, Environmental , Hydrogensulfite Reductase/metabolism , Thiosulfates , Nitrates/metabolism , Sulfur/metabolism , Bacteria/metabolism , Oxidation-Reduction , Oxidoreductases/metabolism , Sulfides/metabolism , Soil , Sulfamethoxazole/metabolism , Sulfites/metabolism , Alkalies , Quinones
11.
Case Rep Neurol ; 14(2): 237-244, 2022.
Article in English | MEDLINE | ID: mdl-35815107

ABSTRACT

Stiff Person Syndrome (SPS) is an extremely rare neurological condition characterized by muscle stiffness and painful muscle spasms. The symptoms often progress slowly and can cause disability. Antibodies to glutamic acid decarboxylase (anti-GAD) have been reported in up to 80% of the classic type of SPS. Paraneoplastic syndrome comprises 5% of SPS cases. These patients present with different malignancies including lung, thymus, breast, colon, and lymph nodes. In this paper, we report a case of a 25-year-old Vietnamese female patient with SPS presenting with unusual clinical manifestations of sudden onset, rapidly progressive spinal, abdominal, and lower limb rigidity accompanied by painful spasms, autonomic disorders, and severe, multiple bone fractures. Serologic tests detected high-titer anti-GAD, combined with anti-SOX1 antibodies, suggesting paraneoplastic SPS. Intravenous immunoglobulin has been employed as the main treatment therapy, and the patient has had a complete remission.

12.
Angew Chem Int Ed Engl ; 61(34): e202207966, 2022 08 22.
Article in English | MEDLINE | ID: mdl-35716396

ABSTRACT

The putative interaction of a C-F bond with an amide carbonyl has been an intriguing topic of interest in this century for reasons spanning basic physical organic chemistry to biochemistry. However, to date, there exist no examples of a close, well-defined interaction in which its unique aspects can be identified and exploited. Herein, we finally present an engineered system possessing an exceptionally tight C-F-amide interaction, allowing us to obtain spectroscopic, crystallographic, and kinetic details of a distinctive, biochemically relevant chemical system for the first time. In turn, we also explore Lewis acid coordination, C-F bond promotion of amide isomerization, enantiomerization, and ion protonation processes.


Subject(s)
Amides , Amides/chemistry , Crystallography , Kinetics , Spectrum Analysis
13.
Healthcare (Basel) ; 10(4)2022 Apr 18.
Article in English | MEDLINE | ID: mdl-35455928

ABSTRACT

Background: Children are at high risk of drug-related problems, increased risk of treatment failures, and high treatment costs. We aimed to evaluate the effect of pharmacist-led interventions on physicians' prescribing for pediatric outpatients. Methods: A prospective study with pre- and post-intervention measurement assessment was conducted to collect pediatric outpatients' prescriptions during the pre-intervention period (January 2020) and post-intervention (August 2020) at a children's hospital in Vietnam. Drug-related problems were identified and categorized according to Pharmaceutical Care Network Europe (PCNE), version 9.1. The intervention program was developed based on the results of pre-intervention observations. After the intervention, prescriptions were evaluated. Statistical tests were used to compare the proportions of drug-related problems before and after the intervention and to identify factors related to drug-related problems. Results: There were 2788 out of 4218 (66.1%) prescriptions with at least one drug-related problem before the intervention. Of these drug-related problems, the most common was inappropriate timing of administration and incorrect dosage (36.1% and 35.6%, respectively). After the intervention, the percentage of prescriptions with at least one drug-related problem was 45.5% (p < 0.001). Most of the drug-related problem types decreased significantly (p < 0.05). The binary logistic regression analysis results showed that in addition to pharmacists' intervention, patients' gender, primary disease, comorbidity status, and the total number of drugs prescribed were also factors related to drug-related problems. Conclusions: Drug-related problems in pediatric outpatients were quite common. Pharmacists' intervention helped to improve the prevalence and types of drug-related problems.

14.
J Clin Lab Anal ; 36(5): e24355, 2022 May.
Article in English | MEDLINE | ID: mdl-35312118

ABSTRACT

BACKGROUND: The COVID-19 pandemic caused by SARS-CoV-2 remains public health burdens and many unresolved issues worldwide. Molecular assays based on real-time RT-PCR are critical for the detection of SARS-CoV-2 in clinical specimens from patients suspected of COVID-19. OBJECTIVE: We aimed to establish and validate an in-house real-time RT-PCR for the detection of SARS-CoV-2. METHODOLOGY: Primers and probes sets in our in-house real-time RT-PCR assay were designed in conserved regions of the N and E target genes. Optimized multiplex real-time RT-PCR assay was validated using the first WHO International Standard (NIBSC code: 20/146) and evaluated clinical performance. RESULTS: The limit of detection validated using the first WHO International Standard was 159 IU/ml for both E and N target genes. The evaluation of clinical performance on 170 clinical samples showed a positive percent agreement of 100% and the negative percent agreement of 99.08% for both target genes. The Kappa value of 0.99 was an excellent agreement, the strong correlation of Ct values observed between two tests with r2  = 0.84 for the E gene and 0.87 for the N gene. Notably, we assessed on 60 paired saliva and nasopharyngeal samples. The overall agreement was 91.66%, and Kappa value of 0.74 showed a high agreement between two types of samples. When using nasopharyngeal swabs as the reference standard, positive percent agreement, and negative percent agreement were 91.83% and 90.90%, respectively. CONCLUSION: In the present study, we established and validated an in-house real-time RT-PCR for molecular detection of SARS-CoV-2 in a resource-limited country.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , Humans , Nasopharynx , Pandemics , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/genetics , Sensitivity and Specificity , World Health Organization
15.
J Environ Manage ; 301: 113868, 2022 Jan 01.
Article in English | MEDLINE | ID: mdl-34628282

ABSTRACT

Knowing the effluent quality of treatment systems in advance to enable the design of treatment systems that comply with environmental standards is a realistic strategy. This study aims to develop machine learning - based predictive models for designing the subsurface constructed wetlands (SCW). Data from the SCW literature during the period of 2009-2020 included 618 sets and 10 features. Five algorithms namely, Random forest, Classification and Regression trees, Support vector machines, K-nearest neighbors, and Cubist were compared to determine an optimal algorithm. All nine input features including the influent concentrations, C:N ratio, hydraulic loading rate, height, aeration, flow type, feeding, and filter type were confirmed as relevant features for the predictive algorithms. The comparative result revealed that Cubist is the best algorithm with the lowest RMSE (7.77 and 21.77 mg.L-1 for NH4-N and COD, respectively) corresponding to 84% of the variance in the effluents explained. The coefficient of determination of the Cubist algorithm obtained for NH4-N and COD prediction from the test data were 0.92 and 0.93, respectively. Five case studies of the application of SCW design were also exercised and verified by the prediction model. Finally, a fully developed Cubist algorithm-based design tool for SCW was proposed.


Subject(s)
Machine Learning , Wetlands , Algorithms , Nitrogen
16.
Geriatrics (Basel) ; 6(4)2021 Dec 12.
Article in English | MEDLINE | ID: mdl-34940341

ABSTRACT

The proportion of geriatric depression recorded in Vietnam was 66.9%. Depression in older people is a risk factor for problems related to dementia, poor quality of life, and suicide. To have a good Vietnamese questionnaire for assessing geriatric depression, we conducted the study to translate and cross-culturally adapt the Geriatric Depression Scale-long-form with 30 items (GDS-30). The study has two steps. Step 1 is a translation of the GDS-30 scale. We followed the guideline by Beaton et al., (2000 & 2007). Firstly, two translators (informed and uninformed) translated the questionnaires. Secondly, the translations were synthesized. Thirdly, back translation was performed by two translators fluent in both Vietnamese and English but completely unknown of the original version of the scale and did not have medical expertise. Finally, seven experts reached a consensus on the pre-final Vietnamese version (GDS-30). Step 2 is a field test of the questionnaires on people 60 years or older. Then, we determined the internal consistency and test-retest reliability of the questionnaire in 55 Vietnamese inpatients in a geriatric department. Construct validity was determined by examining the relationship between depressive scores and patient characteristics. The Vietnamese version of GDS-30 was built with the agreement of all experts on the semantic, idiomatic, experiential, and conceptual equivalences between the original and pre-final Vietnamese versions of the GDS-30. The Cronbach's alpha coefficient value was 0.928, indicating the items' adequate internal consistency. Spearman's correlation coefficient value of total scores between the first and second interviews showed medium correlation (0.479, p < 0.001), and the stability is acceptable. The GDS-30 scale reached the construct validity because the proportion of geriatric depression according to GDS-30 was significantly different between characteristics groups, such as gender, employment, level of education, economic status, and sleep disturbance. The Vietnamese version of the GDS-30 scale had high consistency, satisfactory reliability, and understanding and can be used as a screening tool for depression in elderly patients in primary healthcare centers. This is the first depression rating scale for the elderly in Vietnam to be translated and validated. Non-psychiatric health professionals or patients can quickly self-assess and screen for the illness.

17.
Nanomaterials (Basel) ; 11(6)2021 Jun 17.
Article in English | MEDLINE | ID: mdl-34204514

ABSTRACT

Nanodiamond (ND) has recently emerged as a potential nanomaterial for nanovaccine development. Here, a plant-based haemagglutinin protein (H5.c2) of A/H5N1 virus was conjugated with detonation NDs (DND) of 3.7 nm in diameter (ND4), and high-pressure and high-temperature (HPHT) oxidative NDs of ~40-70 nm (ND40) and ~100-250 nm (ND100) in diameter. Our results revealed that the surface charge, but not the size of NDs, is crucial to the protein conjugation, as well as the in vitro and in vivo behaviors of H5.c2:ND conjugates. Positively charged ND4 does not effectively form stable conjugates with H5.c2, and has no impact on the immunogenicity of the protein both in vitro and in vivo. In contrast, the negatively oxidized NDs (ND40 and ND100) are excellent protein antigen carriers. When compared to free H5.c2, H5.c2:ND40, and H5.c2:ND100 conjugates are highly immunogenic with hemagglutination titers that are both 16 times higher than that of the free H5.c2 protein. Notably, H5.c2:ND40 and H5.c2:ND100 conjugates induce over 3-folds stronger production of both H5.c2-specific-IgG and neutralizing antibodies against A/H5N1 than free H5.c2 in mice. These findings support the innovative strategy of using negatively oxidized ND particles as novel antigen carriers for vaccine development, while also highlighting the importance of particle characterization before use.

19.
Environ Sci Pollut Res Int ; 26(21): 21109-21126, 2019 Jul.
Article in English | MEDLINE | ID: mdl-31134537

ABSTRACT

Post-industrial era has witnessed significant advancements at unprecedented rates in the field of medicine and cosmetics, which has led to affluent use of pharmaceuticals and personal care products (PPCPs). However, this has exacerbated the influx of various pollutants in the environment affecting living organisms through multiple routes. Thousands of PPCPs of various classes-prescription and non-prescription drugs-are discharged directly into the environment. In this review, we have surveyed literature investigating plant-based remediation practices to remove PPCPs from the environment. Our specific aim is to highlight the importance of plant-bacteria interplay for sustainable remediation of PPCPs. The green technologies not only are successfully curbing organic pollutants but also have displayed certain limitations. For example, the presence of biologically active compounds within plant rhizosphere may affect plant growth and hence compromise the phytoremediation potential of constructed wetlands. To overcome these hindrances, combined use of plants and beneficial bacteria has been employed. The microbes (both rhizo- and endophytes) in this type of system not only degrade PPCPs directly but also accelerate plant growth by producing growth-promoting enzymes and hence remediation potential of constructed wetlands.


Subject(s)
Biodegradation, Environmental , Pharmaceutical Preparations/analysis , Waste Disposal, Fluid/methods , Water Pollutants, Chemical/analysis , Wetlands , Bacteria/metabolism , Cosmetics/analysis , Endophytes/metabolism , Plant Development , Water Microbiology
20.
Chemosphere ; 184: 375-383, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28605708

ABSTRACT

The sulfur cycle in the rhizosphere of constructed wetlands is frequently interlaced with transformations of carbon and nitrogen. Knowledge about the manifold sulfur transformations may thus aid in improving treatment performance of constructed wetlands. In this study, two laboratory-scale constructed wetland models (planted fixed bed reactors; PFR1 and PFR2) were used to investigate inorganic sulfur transformations at various total loads of sulfate and organic carbon. Sulfate, sulfide and elemental sulfur were the most abundant sulfur compounds detected, thus providing evidence for the simultaneous occurrence of dissimilatory sulfate reduction and sulfide oxidation. This co-occurrence was likely enabled by oxygen micro-gradients in the root-near environment, i.e. aerobic sulfide and elemental sulfur oxidation took place mostly at the roots while sulfate and elemental sulfur reduction occurred in the pore water under reduced redox conditions. The rhizosphere was found to be first sink, then source for sulfur during the course of the experiment. Immobilization of reduced sulfur was triggered by catabolism of organic matter coupled to dissimilatory sulfate reduction and the subsequent partial oxidation of generated sulfide. Good plant status was critical for sulfur deposition in the systems. Without externally provided sulfate the sulfur depot of the rhizosphere was a prolonged source for sulfur, which was remobilized into the pore water. Oscillations between sulfide and sulfur (PFR1) or sulfide and sulfate (PFR2) suggested a dynamic interplay between plants and various microbial guilds, i.e. dissimilatory sulfate and sulfur reducers on one side and sulfide and sulfur oxidizers on the other.


Subject(s)
Oxidation-Reduction , Plants/metabolism , Rhizosphere , Sulfur/chemistry , Wetlands , Bioreactors , Carbon/metabolism , Nitrogen/metabolism , Sulfur/metabolism
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