Understanding vermicompost and organic manure interactions: impact on toxic elements, nitrification activity, comammox Nitrospira inopinata, and archaea/bacteria

Vermicompost is a substantial source of nutrients, promotes soil fertility, and maintains or increases soil organic matter levels. Potentially toxic elements (PTEs) in vermicompost impact on nitrification activity. However, it is yet unknown how vermicompost affects nitrifying bacteria and archaea, comammox Nitrospira inopinata (complete ammonia oxidizers), net nitrification rates (NNRs), and PTEs. The effects of vermicompost application on NNRs, potential nitrification rates (NPs), PTEs, and the abundances of comammox N. inopinata bacteria, nitrite-oxidizing bacteria (NOB), and ammonia-oxidizing bacteria (AOB)/archaea (AOA) were studied. NNRs and NPs were significantly higher (p < 0.05) in fresh cow-dung vermicompost (stored for 40 days) as compared with other organic manure. The level of PTEs (Cu2+, Fe2+, Pb2+, Cd2+, and Zn2+) was significantly lower (p < 0.05) in vermicompost as compared with compost of waste material with Trichoderma and cow dung. Comammox N. inopinata, NOB, AOB, and AOA were significantly higher (p < 0.05) in stored cow-dung vermicompost (more than 1 year) as compared with other organic manure. The results of the scatterplot matrix analysis suggested that Fe2+, total nitrogen (TN), soil organic carbon (SOC), and total carbon (TC) were linearly correlated (p < 0.001) with NNRs and NPs in vermicompost and organic manure. Similarly, comammox N. inopinata bacteria, NOB, AOB, and AOA were linearly correlated (p < 0.001) with NNR and NP. These results indicated that vermicompost promoted nitrification activity by increasing microbial diversity and abundance, supplying nutrients and organic matter for microbial growth, and facilitating complex microbial interactions. It may be concluded that the influence of vermicompost, which played a great role in PTE concentration reduction, increased chemical, and biological properties, increased the growth rate of nitrifying bacteria/archaea and the nitrogen cycle.

Near-miss accidents data analysis and knowledge dissemination in water construction projects in Oman

The strategic role of near-miss data in safety management is undeniably vital. This data provides early warnings of potential accidents, thus serving as a proactive tool for recognizing weak points in safety management and preventing disasters. Reinforcing this premise, an investigation was launched to delve into the classification and analysis of near-miss accident data, aiming to augment safety prevention knowledge in the Nama Water Services (NWS) Company. The study engaged in comprehensive activities, including gathering near-miss reports, engaging with HSE personnel, formulating a standardized near-miss data form, and analyzing the collected data. Additionally, it proposed a structured guideline for identifying, analyzing, and classifying near-miss incidents, hinging on various parameters like types of hazards, operations, time of occurrence, and project segments. The findings highlighted that the construction projects involving pipelines and reservoirs experienced the most incidents, predominantly occurring during weekday mornings and afternoons. Major hazards included falls from scaffolds, falls within trenches, and lax housekeeping. Most notably, the operations most frequently associated with near-miss incidents were excavation, lifting, and loading. A deep dive into the root causes revealed that poor supervision, inadequacies in the safe work system, insufficient control measures, and inadequate training were the primary culprits. Furthermore, the study indicated that workers and equipment bore the brunt of these incidents.

A new treatment step of bioelectrochemically treated leachate using natural clay adsorption towards sustainable leachate treatment

Standalone and combined leachate treatment mechanisms suffer from low treatment efficiencies due to leachate's complex, toxic, and recalcitrant nature. Bioelectrochemical system (BES) was used for the first time to investigate the treatment of leachate mixed wastewater (WW) (i.e., diluted leachate, DL) (DL ≈ L:WW = 1:4) to minimize these complexities. A natural clay (palygorskite) was used as adsorbent material for further treatment on the BES effluent (EBES) while using two different masses and sizes (i.e., 3 g and 6 g of raw crushed clay (RCC) and 75 μ of sieved clay (75 μSC)). According to bioelectrochemical performance, BES, when operated with low external resistance (Rext = 1 Ω) (BES 1), showed a high removal of COD and NH3-N with 28% and 36%, respectively. On the other hand, a high Rext (100 Ω, BES 100) resulted in low removal of NH3-N with 10% but revealed high COD removal by 78.26%. Moreover, the 6 g doses of 75 μSC and RCC showed the maximum COD removals of 62% and 38% and showed the maximum removal of NH3-N with an average range of 40% for both sizes. After efficient desorption, both clay sizes resulted in regeneration performance which was observed with high COD (75%) and NH3-N (34%) on EBES. Therefore, when BES and clay adsorption technique sequentially treated and achieved with combined removal of ~ 98% for COD and ~ 80% of NH3-N, it demonstrated an efficient treatment method for DL treatment.

Energy consumption, CO2 emissions, foreign direct investment, and economic growth in Malaysia: an NARDL technique

This study seeks to ascertain whether there is an unbalanced link  between CO₂ emissions, foreign direct investment, and economic growth in Malaysia over a 40-year timeframe between 1980 and 2019. We investigated the asymmetric relationship , using  non-linear autoregressive distributed lag (NARDL) technique. The findings showed a noteworthy asymmetry between FDI, CO₂ emissions, and GDP in Malaysia. The long-term and short-term effects of negative FDI on GDP are both equivalent to 0.028 and 0.021, respectively. This suggests that, compared to short-term fluctuations, long-term negative FDI adjustments have a considerably more negative impact on economic growth. The coefficient of positive (CO₂⁺) and negative (CO₂^-) changes in economic growth is equal to 0.086 and - 0.152, respectively. It indicates that positive changes in CO₂ emissions have stronger effects in the long run than negative shocks. Considering an asymmetric association between these two variables in the short and long term, Malaysian policymakers must comprehend the dynamic relationship between FDI, CO2 emissions, and GDP to plan appropriate economic and environmental policies that will support sustainable economic development and ensure a safer environment.

Pharmacoinformatics and molecular dynamics simulation approach to identify anti-diarrheal potentials of Centella asiatica (L.) Urb. against Vibrio cholerae

Vibrio cholerae, the etiological agent of cholera, causes dehydration and severe diarrhea with the production of cholera toxin. Due to the acquired antibiotic resistance, V. cholerae has drawn attention to the establishment of novel medications to counteract the virulence and viability of the pathogen. Centella asiatica is a medicinal herb native to Bangladesh that has a wide range of medicinal and ethnobotanical applications including anti-bacterial properties. In the present investigation, a total of 25 bioactive phytochemicals of C. asiatica have been screened virtually through molecular docking, ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) analyses, and molecular dynamics simulation. Our results revealed four lead compounds as Viridiflorol (-8.7 Kcal/mol), Luteolin (-8.1 Kcal/mol), Quercetin (-8.0 Kcal/mol) and, Geranyl acetate (-7.1 Kcal/mol) against V. cholerae Toxin co-regulated pilus virulence regulatory protein (ToxT). All the lead compounds have been found to possess favorable pharmacokinetic, pharmacodynamics, and molecular dynamics properties. Toxicity analysis revealed satisfactory results with no major side effects. Molecular dynamics simulation was performed for 100 ns that revealed noteworthy conformational stability and structural compactness for all the lead compounds, especially for Quercetin. Target class prediction unveiled enzymes in most of the cases and some experimental and investigational drugs were found as structurally similar analogs of the lead compounds. These findings could aid in the development of novel therapeutics targeting Cholera disease and we strongly recommend in vitro trials of our experimental findings.Communicated by Ramaswamy H. Sarma.

Telemedicine Use and the Perceived Risk of COVID-19: Patient Experience

INTRODUCTION

The COVID-19 outbreak resulted in an increased demand for telemedicine worldwide. Telemedicine is a technology-based virtual platform that allows the exchange of clinical data and images over remote distances. This study aims to examine the impact of the perceived risk of COVID-19 on telemedicine use in Bangladesh.

METHODS

This explanatory study was conducted in hospital settings across Dhaka city in Bangladesh. Patients were eligible to participate if they were aged 18 years or over and had used telemedicine in a hospital at least once since the COVID-19 outbreak. Outcome variables included sociodemographic, the perceived risk of COVID-19, and telehealth use. Study data were collected using an online and paper-based survey.

RESULTS

A total of 550 patients participated in this study, mostly male (66.4%), single (58.2%), and highly educated (74.2%). The means of the different domains of telemedicine use reflected a high degree of perceived benefit, accessibility, and satisfaction but a lower degree of privacy and discomfort, care personnel expertise, and usability. COVID 19 perceived risk predicted between 13.0% and 26.6% of variance in telemedicine domains, while the effects of demographic variables were controlled or removed. The perceived risk of COVID-19 was negatively correlated with privacy and discomfort, as well as care personnel concerns. Low and high levels of perceived COVID-19 risk were less likely to encourage the use of telemedicine as a risk reduction tool.

DISCUSSION

The participants were mainly satisfied with telemedicine, finding it beneficial and accessible; however, many were concerned about privacy, care personnel expertise, and its usability. The perceived risk of COVID-19 was a strong predictor (contributor) of telemedicine use, suggesting that risk perception can be used to encourage telemedicine use as a risk reduction strategy during pandemics; however, a medium level of risk was more promising.

Enhancing methane production of co-digested food waste with granular activated carbon coated with nano zero-valent iron in an anaerobic digester

Anaerobic digestion (AD) possesses dual benefits of waste treatment and energy generation. The use of conductive additives in AD matrix has potential to improve process yield. Hence, the study aimed to investigate a thermophilic AD (TAD) inserted by granular activated carbon coated with nano zero-valent iron (GAC/nZVI) in the matrix and was operated for mono-digestion and co-digestion of cow manure with food wastes (rice and bread) to check the bioprocess improvement. The results were compared with the control TAD without conductive additives. Biogas production increased by 11 folds upon using GAC/nZVI addition compared to the control TAD. Moreover, the addition of GAC/nZVI increased the methane in biogas by 20.7 folds compared to control one. With GAC/nZVI, the maximum COD removal of 78.29% and 85.21% were noticed for co-digestion and mono digestion, respectively. Such improvement of TAD performance was due to easy bacterial communication and electron exchange through the conductive particles.

Optimizing Fenton-like process, homogeneous at neutral pH for ciprofloxacin degradation: Comparing RSM-CCD and ANN-GA

Antibiotics are considered among the most non-biodegradable environmental contaminants due to their genetic resistance. Considering the importance of antibiotics removal, this study was aimed at multi-objective modeling and optimization of the Fenton-like process, homogeneous at initial circumneutral pH. Two main issues, including maximizing Ciprofloxacin (CIP) removal and minimizing sludge to iron ratio (SIR), were modeled by comparing central composite design (CCD) based on Response Surface Methodology (RSM) and hybrid Artificial Neural Network-Genetic Algorithm (ANN-GA). Results of simultaneous optimization using ethylene diamine tetraacetic acid (EDTA) revealed that at pH ≅ 7, optimal conditions for initial CIP concentration, Fe²⁺ concentration, [H₂O₂]/[Fe²⁺] molar ratio, initial EDTA concentration, and reaction time were 14.9 mg/L, 9.2 mM, 3.2, 0.6 mM, and 25 min, respectively. Under these optimal conditions, CIP removal and SIR were predicted at 85.2% and 2.24 (gr/M). In the next step, multilayer perceptron (MLP) and radial basis function (RBF) artificial neural networks (ANN) were developed to model CIP and SIR. It was concluded that ANN, especially multilayer perceptron (MLP-ANN) has a decent performance in predicting response values. Additionally, multi-objective optimization of the process was performed using Genetic Algorithm (GA) and Non-dominated Sorting Genetic Algorithm-II (NSGA-II) to maximize CIP removal efficiencies while minimizing SIR. NSGA-II optimization algorithm showed a reliable performance in the interaction between conflicting goals and yielded a better result than the GA algorithm. Finally, TOPSIS method with equal weights of the criteria was applied to choose the best alternative on the Pareto optimal solutions of the NSGA-II. Comparing the optimal values obtained by the multi-objective response surface optimization models (RSM-CCD) with the NSGA-II algorithm showed that the optimal variables in both models were close and, according to the absolute relative error criterion, possessed almost the same performance in the prediction of variables.

Virtual screening reveals liquiritigenin as a broad-spectrum inhibitor of SARS-CoV-2 variants of concern: an in silico study

The SARS-CoV-2 has severely impacted the lives of people worldwide. Global concern is on the rise due to a large number of unexpected mutations in the viral genome, resulting in new variants. Nature-based bioactive phytochemicals hold great promise as inhibitors against pathogenic viruses. The current study was aimed at evaluating some bioactive antiviral phytochemicals against SARS-CoV-2 variants of concern. A total of 46 phytochemicals were screened against the pathogenic spike protein of Alpha, Beta, Delta, Gamma, and Omicron variants. In addition to molecular docking, screening for favorable pharmacokinetic and pharmacodynamic properties such as absorption, distribution, metabolism, excretion, and toxicity was undertaken. For each of the aforementioned five SARS-CoV-2 variants of concern, a 100 ns molecular dynamics simulation was run to assess the stability of the complexes between their respective spike protein receptor-binding domain and the best-selected compound. From our current investigation, the natural compound liquiritigenin turned out to be the most promising potential lead compound against almost all the variants. These findings could pave the way for the development of effective medications against SARS-CoV-2 variants. However, in vivo trials in future studies are necessary for further validation of our results.Communicated by Ramaswamy H. Sarma.

Impact of COVID-19 pandemic on aircraft noise levels, annoyance, and health effects in an urban area in Oman

This study aimed at investigating aircraft noise exposure levels, their annoyance, and potential health effects among communities living within airport catchment areas during the COVID-19 pandemic. Both field measurements and an online survey approach were used to investigate aircraft noise exposure levels, annoyance, and general health effects among residents living near Muscat International Airport (MCT) in Muscat, Oman, amid the COVID-19 period. The study found a drastic decline in aircraft noise levels due to the introduction of COVID-19 intervention measures such as lockdowns, social distancing, and closure of airports. In June 2020, during the COVID-19 pandemic, average daily aircraft noise levels of LAeq (39.9 dB(A)) and Lmax (49.7 dB(A)) was observed compared to the previous year (April-May 2019) of 58.5 and 76.8 dB(A), indicating aircraft noise reductions level of 32% and 35%, respectively. The results of the online social survey among 187 participants showed that most (58.8%) of the respondents did not feel that the level of noise produced by aircraft causes annoyance. During the day, the vast majority of the interviewees did not complain of any annoyance during the morning (45.5%), afternoon (39.6%), and evening (31%) with only < 4% of residents have reported a very high degree of annoyance of during COVID-19 pandemic period. Very few people (17%) did complain of experiencing general health problems while 29% did not know of any potential health effects that could be attributed to aircraft noise exposures. Aircraft noise annoyance complaints among the As-Seeb residents during the pre-COVID-19 pandemic periods were reported to be extremely high reaching about 84% compared to 41% during this current COVID-19 pandemic period. These findings support the need to develop future sustainable noise mitigation policies in order to help reduce noise exposures and improve human health during post-COVID-19 pandemic periods.

Effect of ambient noise on indoor environments in a health care facility in Oman

Hospital-noise levels can induce physiological responses and affect sleep quality, which could contribute to cardiovascular-related health problems. Till date, high-resolution hospital noise exposure assessment studies have not received much attention in Oman. This study aims at assessing sound pressure levels across hospital wards and intensive care unit (ICU) rooms to determine annoyance and potential health effects based on perception and risk estimates. An indoor exposure assessment using high precision noise sensors was conducted in a female medical ward (FMW), isolated ward (SLW), emergency ward (EMW), and intensive care unit (ICU) in a public hospital in Muscat city, Oman. Self-administered questionnaire was randomly distributed among respondents using both online and field survey approach to ascertain annoyance, health effects, and potential risks associated with exposure. The study found that 24-h noise levels (L_Aeq) ranged from 55.2 to 61.7 dB(A) in the hospital wards and ICU rooms, which exceeded WHO's hospital indoor rooms critical limit of 35 dB(A) by 58-76%. A total of 150 participants took part in the survey. Among the respondents, 53% reported moderate annoyance at the hospital wards, while 56% felt sensitivity to the noise levels. Noise annoyance was reported by the majority of the patients across the various wards and emergency rooms as causing slight annoyance (50%) and intermittent sleep disturbances (49%). The majority (73%) of the medical staff have complained that the current noise levels affect overall work performance (p = 0.004), while 70% of them have further complained of it as a cause of workplace distraction (p = 0.011). Logistic binary regression analysis has revealed that the complaint of noise sensitivity has a positive association with noise levels in VCW (OR: 1.54; 95% CI: 0.92-2.58), and reported loss of concentration by the medical staff also associated with noise levels at the EMW (OR: 1.61; 95% CI: 0.65-4.01). Quantitative risk estimates showed that both the percentages of highly annoyed (HA) persons (16%), and highly sleep-disturbed (HSD) persons (9%) were very high in FMW, while ICU was found to have the lowest risk. However, the greater number of the respondents (87%) believed that there are possibilities of mitigating (p < 0.001) the current noise levels.

Assessment of noise levels and induced annoyance in nearby residential areas of an airport region in Oman

There is adequate evidence from epidemiological studies showing an association between noise exposures and incidence of cardiovascular diseases and cognitive impairment among exposed populations. This study aimed to investigate noise exposure levels in an airport region and their effects on the nearby two neighborhood communities (i.e., Al Seeb and Bawshar). To achieve this, noise levels were measured across 15 different points within the communities for more than 3 weeks at a median distance of 3.5 km from the airport runways using a sound level analyzer. In addition, we conducted an online social survey in a random sampling of a total of 913 residents who were living closer to the airport. A combination of a 5-point scale and 3-point Likert scale was used to assess the resident population's noise annoyance and the potential health impacts. The results revealed that the majority of the measured points have noise levels (55.71-65.24 L_Aeq dBA) exceeding both Oman and WHO critical limits. There was a general decrease in noise levels at points further away from the runways; thus, at points 2.5, 4.8, and 8.8 km, sound pressure levels were found to be 63.08, 57.41, and 52.31 dBA, respectively. However, steady noise levels were observed throughout most of the daily (24 h) measurements indicating continual exposures. Overall, 44.6% of residents reported noise annoyance level as very high, with Al Seeb inhabitants (46%) eliciting a greater percentage of annoyance levels compared to Bawshar (5%) due to their closer proximity to the airport. Also, the noise was significantly (p ˂ 0.001) associated with sleep disturbance, insomnia, irritation, and frightening. The majority of the residents complained of an increase in insomnia (41.5%), stress (34.3%), headache (47.3%), and cardiovascular diseases (16.2%). With the question of reducing noise exposures, about 41% of the respondents have plans of relocating to distant areas with low noise levels.

Characterization and exposure assessment to urban air toxics across Middle Eastern and North African countries: a review

Middle East and North African (MENA) countries over the decades are experiencing rapid industrial and infrastructural growth combined with being the global hub of oil and gas industries. These economic transformations are associated with release of air pollutants including urban air toxics (UAT) through industrial, traffic, and constructional activities into ambient urban environments. UAT concentrations levels may exacerbate in most MENA countries considering high number of vehicular traffic populations and petrochemical industries which are one of the main sources of this pollutant. Therefore, the main objective of the study is to review major findings of UAT levels in urban areas across thirteen (13) MENA countries. The study characterizes various measured UAT, assesses their concentrations in ambient environment, and identifies their major sources of emissions by reviewing more than 100 relevant UAT papers across the selected MENA countries. It was found that benzene, heavy metals, formaldehyde, and dioxin-like compounds are the most reported UAT. The study concluded that road traffic, fuel stations, and petrochemical industries were identified as the main sources of ambient UAT levels. It was further reported that most of the studies were based on short-term ambient environment with limited studies in indoor environments. Therefore, it is highly recommended that future research should focus on innovative health impact assessment and epidemiological studies from exposure to UAT levels. Also embarking on sustainable mitigation approaches through urban greenery, eco-industrial estates infrastructural developments, and renewable energy shares will reduce UAT levels and improve human health.

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

BACKGROUND

Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality.

METHODS

We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis.

FINDINGS

We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36-39) and median bodyweight at presentation was 2·8 kg (2·3-3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88-4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59-2·79], p<0·0001), sepsis at presentation (1·20 [1·04-1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4-5 vs ASA 1-2, 1·82 [1·40-2·35], p<0·0001; ASA 3 vs ASA 1-2, 1·58, [1·30-1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02-1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41-2·71], p=0·0001; parenteral nutrition 1·35, [1·05-1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47-0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50-0·86], p=0·0024) or percutaneous central line (0·69 [0·48-1·00], p=0·049) were associated with lower mortality.

INTERPRETATION

Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030.

FUNDING

Wellcome Trust.

A review of mechanisms underlying the impacts of (nano)microplastics on anaerobic digestion

The presence of (nano)microplastics in domestic wastewater and their subsequent release to the aquatic environment via the discharge of treated sewage has raised significant concerns. Previous studies have also identified their excessive accumulation in sewage sludge. Anaerobic digestion is one of the most used sludge stabilization methods in wastewater treatment plants. Therefore, understanding the potential effects of (nano)microplastics on anaerobic digestion has been receiving increasing attention from researchers. This article provides a comprehensive review of mechanisms underlying the impacts of (nano)microplastics on anaerobic digestion. Notably, this review covers mechanisms of inhibition/enhancement of anaerobic digestion by (nano)microplastics and their potential impacts on biochemical pathways, key enzymes, functional genes, and microbial communities investigated to date. Moreover, potential environmental risks of biosolids contaminated with (nano)microplastics were highlighted. Finally, knowledge gaps and future research needs were outlined. This review will guide more standardized studies in the future, covering both fundamental and engineering aspects.

Groundwater contamination in the Gulf Cooperation Council (GCC) countries: a review

Groundwater quality levels are currently deteriorating in Gulf Cooperation Council (GCC) countries due to excessive surface and subsurface human activities. Agricultural and industrial activities, landfill seepage and seawater intrusion have been attributed to the deterioration of groundwater quality in GCC states. Such a deterioration of groundwater quality could affect water security in the region, including human health and the ecosystem. Therefore, this review aims to identify the key causes of groundwater contamination across the GCC countries from the published literature. In addition, the review summarizes the major components of the groundwater contaminants across the GCC countries. The results have shown that heavy metals, several cations and anions are the leading cause of groundwater pollution. In most cases, the level of metals and ion contaminants exceeds both the local and international water quality standards. The results have observed the presence of high levels of coliform and radioactive elements in groundwater, especially Uranium and Radium, thereby posing additional risk to human health through consumption. Considering the scarcity of freshwater resources in GCC, urgent actions are required from the decision-makers and relevant regulatory bodies to set up and implement long-term mitigation strategies and stringent policies that will protect the groundwater resources from the adverse effects of anthropogenic activities.

Effect of internal and external resistances on desalination in microbial desalination cell

The green and cost-effective nature of the microbial desalination cell (MDC) make it a promising alternative for future sustainable desalination. However, MDC suffers from a low desalination rate that inhibits it being commercialized. External resistance (R_ext) is one of the factors that significantly affect the desalination rate in MDCs, which is still under debate. This research, for the first time, investigated the impact of R_ext on MDCs with different internal resistance (R_int) of the system to discover the optimal range of R_ext for efficient MDC performance. The results showed that the effect of R_ext on desalination rate (2.52 mg/h) was quite low when the R_int of MDC was high (200 Ω). However, operating the MDC with a low R_int (67 Ω) significantly improved the desalination rate (9.85 mg/h) and current generation. When MDC was operated with a low R_int the effect of variable R_ext on desalination and current generation was noticeable. Therefore, low R_int (67 Ω) MDC was used to select the optimum R_ext when the optimal range was found to be R_ext ≪ R_int, R_ext < R_int, R_ext ≈ R_int (ranging from 1-69 Ω) to achieve the highest desalination rates (10.41-8.59 mg/h). The results showed the superior effect of R_int on desalination rate before selecting the optimal range of R_ext in the outer circuit.

Exposure assessment to road traffic noise levels and health effects in an arid urban area

Road traffic noise exposures have been recognized as serious environmental health concerns, especially in most developing countries with arid climate conditions, rapid increase in vehicle population, and limited traffic management systems. The excessive noise exposure level is associated with increase in the incidence of cardiovascular diseases and anxiety, including annoyance. This study aimed at determining traffic noise levels in residential areas, including the assessment of its annoyance and health effects based on the people's perception and reportage. To do so, field measurement and traffic noise modeling were carried out in six road points to estimate the current noise levels along various roads close to human inhabitants in Muscat Governorate, Sultanate of Oman. The detailed measured noise levels in urban residential areas across the selected roads showed that noise levels have exceeded the local and international threshold limits at all locations during the entire day. The high sound levels (48.0-56.3 dBA) were observed using the US Federal Highway Administration's Traffic Noise Model (TNM, version 2.5) results, which were in agreement with the observed (56.3-60.4 dBA) data. To assess health implication to residents through interviews (n = 208), annoyance at home was found to be little (32%), moderate (28%), and high (9%) in comparison with workplace settings of 42%, 43%, and 15%, respectively. Nineteen percent of the interviewees had difficulties in sleeping, while 19.8% experienced stress due to road traffic noise exposures. Moreover, a strong association (p < 0.05) was established between the use and objection of noise barriers. The study revealed high noise levels and the prevalence of annoyance and health effects among the exposed population. Therefore, immediate action is required to tackle the current noise levels.

Microbial electrochemical systems for hydrogen peroxide synthesis: Critical review of process optimization, prospective environmental applications, and challenges

Hydrogen peroxide (H₂O₂) is an industrial chemical that has been widely adopted for various industrial applications, including water and wastewater treatment. Currently, the majority of H₂O₂ is being produced through the anthraquinone oxidation process, which is disadvantageous due to the requirement of toxic raw materials and high energy input. Recently, microbial electrochemical cells (MXCs), such as microbial fuel cells and microbial electrolysis cells, have demonstrated great potential for effective H₂O₂ production via cathodic oxygen-reduction reaction (ORR). Previous studies have specified key operational parameters for scaling-up of H₂O₂-producing MXCs, where improvements in production rate, conversion efficiency, product concentration and stability are attainable. Moreover, various systems have demonstrated their value proposition in the contaminant removal aspects through direct removal of various environmental pollutants, water disinfection, and many more. This review is intended to highlight promising ways of H₂O₂ production with MXCs and on-site environmental applications of bioelectrochemically-produced H₂O₂.

Impact of building ventilation systems and habitual indoor incense burning on SARS-CoV-2 virus transmissions in Middle Eastern countries

Majority of countries across the globe have employed improving building ventilation, quarantine, social distancing, and disinfections as a general measure of preventing SARS-CoV-2 virus transmissions. However, arid Middle Eastern countries with hot climate (elevated outdoor temperature and humidity levels) are experiencing a different situation. Unfortunately, these harsh ambient climatic conditions in Middle Eastern countries make it impossible for most buildings to utilize natural/mechanical ventilation systems. Besides, indoor air temperatures of most buildings are very low due to overconsumption of air conditioning, thereby, it can be a potential factor of virus spread in most residential homes and public buildings. Most importantly, habitual indoor burning of incense which is the major source of coarse (PM10; aerodynamic diameter <10 μm) and fine (PM2.5; aerodynamic diameter <2.5 μm) particulate matters (PM) could facilitate the transmission of SARS-CoV-2 virus droplets and particles in indoor environments. In fact, it increases the spread of the virus via inhalation in these countries, especially where the wearing of masks is not regulated in public, commercial and residential buildings. It is therefore highly recommended for the relevant public health agencies to critically assess the role of poor indoor environmental conditions including the burning of incense on virus transmissions, which may help to develop control measures for the future viral outbreak effectively.

Evaluation of vehicular pollution levels using line source model for hot spots in Muscat, Oman

A detailed investigation was carried out to assess the concentration of near-road traffic-related air pollution (TRAP) using a dispersion model in Muscat. Two ambient air quality monitoring (AQM) stations were utilized separately at six locations near major roadways (each location for 2 months) to monitor carbon monoxide (CO) and nitrogen oxides (NOx). The study aimed to measure the concentration of near-road TRAP in a city hot spots and develop a validated dispersion model via performance measures. The US Environmental Protection Agency (US EPA) Line Source Model was implemented in which the pollutant emission factors were obtained through Comprehensive Modal Emission Model (CMEM) and COmputer Programme to calculate Emissions from Road Transport (COPERT) model. Traffic data of all vehicle categories under normal driving conditions including average vehicle speed limits and local meteorological conditions were included in the modeling study. The analysis of monitoring data showed that hourly (00:00 to 23:00) concentrations of CO were within the US EPA limits, while NOx concentration was exceeded in most locations. Also, the measured pollutant levels were consistent with hourly peak and off-peak traffic volumes. The overall primary statistical performance measures showed that COPERT model was better than CMEM due to the high sensitivity of CMEM to the local meteorological factors. The best fractional bias (0.47 and 0.39), normalized mean square error (0.44 and 0.50), correlation coefficient (0.64 and 0.70), geometric mean bias (1.07 and 1.57), and geometric variance (2.00 and 2.32) were obtained for CO and NOx, respectively. However, the bootstrap 95% CI estimates over normalized mean square error, fractional bias, and correlation coefficient for COPERT and CMEM were found to be statistically significant from 0 in the case of combined model comparison across all the traffic locations for both CO and NOx. In overall, certain roads showed weak performance mainly due to the terrain features and the lack of reliable background concentrations, which need to be considered in the future study.

Nutritional and sensory quality assessment of plain cake enriched with beetroot powder

The study was aimed to develop cake supplemented by beetroot powder and to evaluate its quality parameter. Four samples were prepared to contain different proportions of beetroot powder (5, 10, 15, and 20% w/w) in combination with wheat flour. The nutritional and sensory properties of plain cakes were also evaluated. The cake supplemented with 15% (w/w) beetroot powder had significantly (p<0.05) improved the nutritional quality compared to control one (without beetroot powder). The mean sensory scores of highly acceptable beetroot powder cake S3 (85:15) had better color (8.57±0.53), flavor (8.43±0.53), texture (8.29±0.49), taste (8.57±0.53) and overall acceptability (8.47±0.13) than other samples. The nutritional and sensory analysis suggested that the cake formulated by 15% (w/w) beetroot powder was comparatively more acceptable than other formulations (0, 5, 10 and 20% w/w).

Association between human health and indoor air pollution in the Gulf Cooperation Council (GCC) countries: a review

Studies on the assessment of indoor air pollutants in terms of concentration and characterization in the Gulf Cooperation Council (GCC) countries have been recently carried out. This review assesses the health effects associated with indoor air pollution exposures in GCC, including other air pollutants (siloxanes, flame retardants, synthetic phenolic antioxidants) which were not explored in a previous study. In addition, the influence of ventilation conditions due to different indoor environments was also investigated. It was revealed that there is a lack of human health assessment studies on most indoor air pollutants in almost all GCC countries, except the United Arab Emirates, Kingdom of Saudi Arabia and Kuwait, where few attempts were made for some specific pollutants. Commonly reported plausible health effects potentially associated with indoor air pollution were related to respiratory symptoms and sick building syndrome (SBS). Many of the current health assessment studies in GCC countries were based on predictions and/or estimates of exposures rather than clinically based observational studies. Measured ventilation levels and indoor air velocities in most buildings failed to meet the American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) threshold limits of 8 L/s/p and 0.18-0.25 m/s, respectively. Additionally, limited studies have investigated respiratory symptoms and SBS potentially attributable to poor ventilation in the region. It is highly recommended that future indoor air quality (IAQ) studies in GCC should focus more on epidemiologic and intervention studies.

Energy recovery and carbon/nitrogen removal from sewage and contaminated groundwater in a coupled hydrolytic-acidogenic sequencing batch reactor and denitrifying biocathode microbial fuel cell

Developing cost-effective technology for treatment of sewage and nitrogen-containing groundwater is one of the crucial challenges of global water industries. Microbial fuel cells (MFCs) oxidize organics from sewage by exoelectrogens on anode to produce electricity while denitrifiers on cathode utilize the generated electricity to reduce nitrogen from contaminated groundwater. As the exoelectrogens are incapable of oxidizing insoluble, polymeric, and complex organics, a novel integration of an anaerobic sequencing batch reactor (ASBR) prior to the MFC simultaneously achieve hydrolytic-acidogenic conversion of complex organics, boost power recovery, and remove Carbon/Nitrogen (C/N) from the sewage and groundwater. The results obtained revealed increases in the fractions of soluble organics and volatile fatty acids in pretreated sewage by 52 ± 19% and 120 ± 40%, respectively. The optimum power and current generation with the pretreated sewage were 7.1 W m^-3 and 45.88 A m^-3, respectively, corresponding to 8% and 10% improvements compared to untreated sewage. Moreover, the integration of the ASBR with the biocathode MFC led to 217% higher carbon and 136% higher nitrogen removal efficiencies compared to the similar system without ASBR. The outcomes of the present study represent the promising prospects of using ASBR pretreatment and successive utilization of solubilized organics in denitrifying biocathode MFCs for simultaneous energy recovery and C/N removal from both sewage and nitrate nitrogen-contaminated groundwater.

Indoor air pollution and exposure assessment of the gulf cooperation council countries: A critical review

Indoor air pollution is one of the human health threat problems in the Gulf Cooperation Council (GCC) countries. In these countries, due to unfavorable meteorological conditions, such as elevated ambient temperature, high relative humidity, and natural events such as dust storms, people spend a substantial amount of their time in indoor environments. In addition, production of physical and biological aerosols from air conditioners, cooking activities, burning of Arabian incense, and overcrowding due to pilgrimage programs are common causes of low quality indoor air in this region. Thus, due to infiltration of outdoor sources as well as various indoor sources, people living in the GCC countries are highly exposed to indoor air pollutants. Inhalation of indoor air pollutants causes mortalities and morbidities attributed to cardiorespiratory, pulmonary, and lung cancer diseases. Hence, the aim of this review study is to provide a summary of the major findings of indoor air pollution studies in different microenvironments in six GCC countries. These include characterization of detected indoor air pollutants, exposure concentration levels, source identifications, sustainable building designs and ventilation systems, and the mitigation strategies. To do so, >130 relevant indoor air pollution studies across the GCC countries were critically reviewed. Particulate matters (PM₁₀ and PM_2.5), total volatile organic compounds (TVOCs), carbon dioxide (CO₂), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and heavy metals were identified as the reported indoor air pollutants. Apart from them, indoor Radon and bioaerosols were studied only in specific GCC countries. Thus, future studies should also focus on the investigation of emerging indoor air pollutants, such as ultrafine and nanoparticles and their associated health effects. Furthermore, studies on the mitigation of indoor air pollution through the development of advanced air purification and ventilation systems could improve the indoor air quality (IAQ) in the GCC region.

Dispersion and deposition estimation of fugitive iron particles from an iron industry on nearby communities via AERMOD

Emission of fugitive iron particles from anthropogenic sources can have significant effects on the human health and the environment. In this study, a regulatory air pollutant dispersion model (AERMOD) was implemented to predict the dispersion and deposition of fugitive iron particles towards a mid-sized residential area in Sultanate of Oman. The performance of the model was validated using air, soil, and dust fall samples. PM₁₀ was found as the most abundant iron particles in the soil samples. The results showed that the maximum daily concentration level of fugitive iron particles simulated through AERMOD was 7.19 μg/m³. Statistical analysis, including fractional bias (FB), normalized mean square error (NMSE), and predicted/observed ratio (Pred./Obs.), showed a reliable agreement in accuracy and precision between the datasets (for air samples FB = 0.024, NMSE = 0.001, Pred./Obs. = 0.976; for dust fall samples FB = -0.004, NMSE = 0.000, Pred./Obs. = 1.004). However, uncertainties and differences were from the external sources, such as other industries in the region. The results presented that the concentration levels were below the national and international guidelines proposed by the US Environmental Protection Agency (USEPA) and Omani Ambient Air Quality Standards (OAAQS). The methodology followed and the developed dispersion model can be generalized to other industries from which the dispersion of fugitive metal particles need to be evaluated as a potential route for human exposure. Graphical abstract ᅟ.

Ambient air quality and exposure assessment study of the Gulf Cooperation Council countries: A critical review

With rapid urbanization and economic growth, many developing countries have faced a greater share of air pollutants in recent years. An increasing number of exposure studies on air pollutants have been reported lately. However, due to lack of strict regulations and monitoring stations among developing countries, such as Gulf Cooperation Council (GCC) countries, limited air pollution and exposure assessment studies have been conducted in this region. Thus, the objective of this critical review was to identify the major sources of air pollutants in the region with hot and arid/semiarid climate for the main categories contributing to specific pollutants. Finally, a summary of the limitations and knowledge gaps were discussed. Additionally, the current available regulations, emission inventories and source apportionment studies in this region were discussed. In this study, the concentration levels of carbon dioxide (CO₂), carbon monoxide (CO), particulate matter (PM), metal elements, nitrogen oxides (NO_x), ozone (O₃), sulfur dioxide (SO₂), volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and persistent organic pollutants (POPs) were reviewed. Due to lack of scientific studies, various databases and indexed journals from early 2000 (sometimes prior that time) were considered. The review findings clearly indicated that the sand, dust (natural and anthropogenic, such as cement, metal, stone cutting industries), chemical industries (refinery, petrochemical, etc.) and transportation activities were the major contributors to the overall air pollution in the GCC countries. Besides, the study recommended that the difference between anthropogenic pollution and natural events in dust formation should be explored extensively. Furthermore, possible suggestions for future researches in the region were proposed.

Characterization of Red Seaweed Extracts Treated by Water, Acid and Alkaline Solutions

Seaweed contained health functional polysaccharides and polyphenols. Five extracts were prepared from red seaweed Melanothamnus somalensis; two of these were aqueous at 20°C (F1) and 70°C (F2), followed by acid (F3), alkali (F4) and acid-washed (F5) treatments. Molecular characteristics of extracts were measured by high-performance liquid chromatography and Fourier transform infrared (FTIR) analyses. Health functionality was determined by sulfate and polyphenol contents, and thermal characteristics were determined by modulated differential scanning calorimetry. Extract F3 contained the highest levels of sulfate followed by F2, F1, F4 and F5, respectively. Similarly, F3 contained the highest polyphenol followed by F4, F2, F1 and F5, respectively. Molecular weight distribution of F1 showed wider distribution of sizes (MW: 1.0 × 103 – 3.0 × 107), and F5 showed a sharp peak (MW: 3.1 × 103); whereas F2, F3 and F4 indicated bimodal distribution. FTIR indicated that all fractions contained agar except F5 and sulfate ester group was attached to carbon 6 of the saccharide.

Analyzing the Status of the Autism Spectrum Disorder Amid Children with Intellectual Disabilities in Bangladesh

Autism spectrum disorders (ASDs) are a collection of conditions characterized by stereo typed behaviors and narrow interests and pervasive problems with communication and social interactions. Globally, researchers are working on identifying the root cause and management of ASD. Although research on autism is at nascent stage in Bangladesh but in terms of social epidemicity, it is currently an utmost important issue. The aim of the study is to analyze the effect of age, sex, birth weight, mother’s pregnancy duration, pregnancy time complicacy and genetic linkage on autism. The study also related, the socio-economic status of the autistic children and satisfaction of parent on government response in this issue. The study was conducted on 50 patients in 2 Autistic Schools (Bangladesh Protibondhi Foundation and Autistic Children Welfare Foundation, Bangladesh) of the Dhaka City from June 2010 to December 2010. Study related data were collected through a predesigned questionnaire In our study out of 50 children with autism 86% were male and 24% were in the age range between 73to 84 months. About 84% children with autism were lived in urban area and about 52% were belonging at the upper middle class. The main signs and symptoms observed, was prefer to play alone (i.e. 74%). Moreover 60% children with autism talks later than age 2 and 58% had poor eye contact. During our study we have observed that 14% children were linked by heredity and 10% have siblings with same problem. Rett syndrome (i.e. 40%) and autistic disorder (i.e., 32%) were more commonly observed. From the prescription, the study revealed, physicians diagnosed speech delay in 32% patient and 8% were diagnosed with attention deficit hyperactivity disorder. For treatment physicians mainly prescribes vitamins (i.e. 50%), antiepileptic drugs (i.e. 12%), and antipsychotic drugs (i.e. 4%). Besides most of the children were treated with physical and occupational therapy but no objection was found with vaccine. During our study we had observed that, 82% parents were not satisfied by the steps taken by the government yet. This study observed that, apart from alarming increase rate of autism in Dhaka City, modern diagnosis and medication facilities as well as therapies are deficit. Therefore, the new born babies and upcoming parents are at great risk due to insufficiency of awareness. So proper awareness programs and more facilities for autistic children should be introduced by both government and non-government sectors.

Contamination and ecological risk assessment of trace elements in sediments of the rivers of Sundarban mangrove forest, Bangladesh

In this study, total concentrations of 16 trace elements (Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, Sb, Hg, Pb, Th and U) in sediments of the rivers of the Sundarban mangrove forest, after the catastrophic oil spill accident in the Sela river of Sundarban, were determined. The overall mean concentrations of V, Cr, Fe and Cd in surface sediments of the Sundarban are remarkably higher than available literature data of those elements. Trace element contamination assessment, using different environmental contamination indices, reveals that As, Sb, Th and U are low to moderately contaminated while Cd is moderately to severely contaminated in the sediments of this area. The multivariate statistical analyses were applied to reveal the origin and behavior of the elements during their transport in the mangrove ecosystem. High Cr, Ni, Cu and As concentrations suggest the risk of potentially adverse biological effects in the ecosystem.

Characteristics of Pores as Measured by Porosimetry and Microscopy Considering Spaghetti as a Model System

Open pore porosity of spaghetti was measured by helium (He) gas pycnometer and mercury (Hg) porosimetry and it was observed as 0.025 and 0.023, respectively. Pore size distribution curve from mercury porosimetry indicated two sharp crests, at alternate position of 59±8 μm and 6.4±0.9 μm diameter pore; while Scanning Electron Microscopy (SEM) showed two types of pores, first class was cracks and second one was holes. The average width of the cracks (channel) and diameters of holes were determined as 3.6±1.5 µm and 1.0±0.3, respectively. The moisture sorption isotherm of spaghetti was measured by dynamic sorption method and modeled by Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAM) models. The values of BET monomolecular layer were observed as 3.24 and 5.91 kg water/kg dry solids, respectively for adsorption and desorption cycles.

Assessment of hydrogen sulfide emission from a sewage treatment plant using AERMOD

Air quality modeling plays an important role in prediction of air pollutants in urban areas. Moreover, it is also an essential component to make crucial decisions in environmental management. In this study, environmental protection agency (EPA) regulatory model (AERMOD) was implemented in order to assess the urban air quality in the city of Muscat, Sultanate of Oman. Dispersion modeling was employed for the prediction of hydrogen sulfide (H₂S) emissions, a neighborhood claimed issue, from Al-Ansab sewage treatment plant (STP). Meteorological, elevation data, and H₂S survey results were implemented into the model. From the site survey study, four different H₂S emission sources were identified as sewage tanker connection points, biofilter, old odor control unit (OCU), and open channels of raw sewage. It was observed that based on maximum 24-h analysis, the ground level concentration outside the STP exceeded the concentration limit, 40 μg/m³, recommended by the local regulating agency in Oman. By applying a sensitivity analysis study, the locations with the highest predicted H₂S levels were identified. The most affected area in the worst-case scenario was the nearby expressway with 450.9 μg/m³ of H₂S. The highest ground level concentration of H₂S was detected in March, while the lowest was measured in December. The model also predicted that the impact of odor nuisance is greater at the summer season than that of other seasons due to the elevated temperatures. The study revealed an adverse environmental impact from the STPs on urban air quality, which may pose a threat to the public health.

Defining the Concept of Innovation and Firm Innovativeness: A Critical Analysis from Resorce-Based View Perspective

<p>The primary objective of this paper is to contribute to the existing literatures by comprehensively reviewing the definitions, concept, as well as the importance of innovative and innovativeness in the business world. This review covers various definitions of innovation and innovativeness, multi dimensions of innovation and how this innovation acts to generate a good firm performance and competitive advantage, relying strongly on the famous Resource-Based View theory. Since the term ‘innovation’ itself is quite difficult to interpret, observe or evaluate, as argued by many scholars, this review attempts to provide discussion and enhance understanding on these concepts especially in the firm’s context. This review could shed some dynamic ideas for future researchers to further identify, conceptualize and understand the underlying theories and perspectives which strongly influence the previous, current and future concept of innovation.</p>

Malignancy in Solitary Thyroid Nodule

This prospective study was done to find out the relative frequency of the malignancy in cold solitary thyroid nodules with other solitary thyroid nodules (hot and warm). This study was carried out in the Department of General Surgery and Otolaryngology-Head & Neck Surgery, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from January 2011 to February 2012. One hundred (100) patients with clinically and ultrasonographically diagnosed as solitary thyroid nodules were included. Out of them, 52% of patients were in the third and fourth decades of life and 26% were in the second decade of life. In sex distribution, females were more affected than males and female: male ratio was 2.1:1. All patients presented with neck swelling, which moved with deglutition and 18% presented with palpitation. Solitary nodule was present in about 60% in the right lobe and 32% in the left lobe. In 72% patients, radioiodine uptake was low; in 25% patient's radioiodine uptake was normal. The thyroid scan revealed 72% cold nodule, in 25% patients radioiodine uptake was normal. On Ultrasonographic study, 60% were solid, 28% cystic and others mixed. Each and every patient of this series was treated surgically. Mostly (73%) lobectomy was done. Total thyroidectomy was done in 16% cases. On histopathology, 56% were colloid nodule, 28% were adenoma and 16% were carcinoma. Among the 16% malignant patients, majority of the patients had their age between 21-48 years. Histopathological types were mostly papillary (50%). Complications of surgery were mostly hoarseness of voice (5%), hematoma (4%), infection (2%) and hypoparathyroidism (3%). In this study, more malignant cases (20.83%) were found in cold solitary nodules.

Accumulation of intermediate denitrifying compounds inhibiting biological denitrification on cathode in Microbial Fuel Cell

BACKGROUND

Bio-cathode denitrifying microbial fuel cell (MFC) is a promising bio-electrochemical system (BES) where both the reactions of anodic oxidation and cathodic reduction are catalyzed by microorganisms. In this nitrogen removal process, a complete biological denitrification from nitrate (NO3 (-)) to molecular nitrogen (N2) was achieved by four reduction steps, forming nitrite (NO2 (-)), nitric oxide (NO) and nitrous oxide (N2O) as intermediate compounds. These enzymatic catalysis reductions are often slowed down on cathode electrode at the higher cathodic nitrate loading. This study investigated the cause for inhibition of the biological denitrification in a three-chambered MFC where the middle chamber acted as denitrifying bio-cathode and the two chambers at the side acted as bio-anode. Carbon fiber brushes were used as electrodes and nafion membranes were used as separator between the chambers.

RESULTS

The maximum power obtained was 14.63 W m(-3) net cathodic compartment (NCC) (Rext =11.5Ω) at an optimum nitrate loading of 0.15 kg NO3 (-)-N m(-3) NCC d(-1). The accumulation of one of the intermediate denitrifying compound, e.g., NO2 (-) adversely affected biological denitrification rate on cathode. According to chemical kinetics, the accumulated NO2 (-) will form free nitrous acid (FNA, HNO2) in aqueous chemical system spontaneously. The study showed that approximately 45 % of the current production and 20 % of the total denitrification was decreased at a FNA concentration of 0.0014 ± 0.0001 mg HNO2 - N L(-1) with an equivalent nitrite concentration of 6.2 ± 0.9 mg NO2 (-) - N L(-1).

CONCLUSIONS

The novel biological process indicates the potential of using denitrifying bio-cathode MFC for green energy production.

Low serum vitamin B-12 and folate concentrations and low thiamin and riboflavin intakes are inversely associated with greater adiposity in Mexican American children

BACKGROUND

Micronutrient status may be a contributing factor to the development of childhood obesity in many industrializing countries passing the nutritional transition. The few studies investigating associations between serum concentrations of vitamin B and intake of B vitamins with adiposity, however, have reported inconsistent findings.

OBJECTIVE

The aim of the study was to examine associations between serum vitamin B-12 and folate concentrations and intakes of B vitamins with body fat by using data on 1131 Mexican American children 8-15 y of age included in NHANES 2001-2004.

METHODS

Children's body mass index (BMI), trunk fat mass (TrFM), and total body fat mass (TBFM) were used as body adiposity (BA) measures. Serum concentrations of folate and vitamin B-12 were measured in blood samples collected from children. Intake of B vitamins was collected according to 24-h dietary recall. Associations of BA with serum concentrations of vitamin B-12 and folate and intake of B vitamins were determined by using linear and multinomial regression models.

RESULTS

Serum concentrations of vitamin B-12 and folate were inversely associated with BMI (β: -2.68, P < 0.01; β = -1.33, P < 0.01), TrFM (β:-3.32, P < 0.01; β: -0.14, P < 0.05), and TBFM (β:-1.93, P < 0.01; β: -3.19; P < 0.01). Higher serum concentrations of vitamin B-12 were associated with a reduced risk of obesity (OR: 0.48; 95% CI: 0.31, 0.77; P < 0.001). Thiamin and riboflavin intakes were inversely associated with BMI (β:-1.35, P < 0.05; β: -1.11, P < 0.05) and TrFM (β:-1.26, P < 0.05; β: -1.37, P < 0.05).

CONCLUSION

Similar inverse associations between BA and status of both vitamin B-12 and folate and intake of thiamin and riboflavin suggest that these micronutrients may play a role in adipogenesis and risk of childhood obesity.

Low serum concentrations of carotenoids and vitamin E are associated with high adiposity in Mexican-American children

Mexican-American children have a high prevalence of overweight/obesity. Micronutrient deficiencies may be contributing to the development of greater adiposity in these children. This study investigated the relations between adiposity and serum concentrations of carotenoids, retinol, and vitamin E among Mexican-American children 8-15 y of age included in the 2001-2004 U.S. NHANES. Associations of the outcomes of children's body mass index (BMI), truncal fat mass (TrFM), and total body fat mass (TBFM) with serum concentrations of α-carotene, cis-β-carotene, trans-β-carotene, retinol, and α-tocopherol were determined by using linear, quantile, and multinomial regression models. BMI was inversely associated with serum concentrations of α-carotene (β = -0.88, P < 0.05), trans-β-carotene (β = -2.21, P < 0.01), cis-β-carotene (β = -2.10, P < 0.01), and α-tocopherol adjusted for total cholesterol ratio (β = -3.66, P < 0.01), respectively. Similar inverse associations were found with TrFM and TBFM. Higher cis-β-carotene and α-tocopherol serum concentrations were associated with reduced probability of overweight (OR: 0.57; 95% CI: 0.37, 0.89; P < 0.05; and OR: 0.56; 95% CI: 0.37, 0.86; P < 0.05; respectively) and obesity (OR: 0.39; 95% CI: 0.26, 0.58; P < 0.01; and OR: 0.38; 95% CI: 0.24, 0.60; P < 0.01; respectively). Higher retinol serum concentrations were associated with increased probability of overweight and obesity (OR: 2.01; 95% CI: 1.26, 3.22; P < 0.01; and OR: 2.90; 95% CI: 1.65, 5.09; P < 0.01; respectively). Significant inverse associations were found between serum concentrations of carotenoids and vitamin E and adiposity among Mexican-American children, but serum retinol concentrations were positively associated with adiposity. Future research is needed to understand the causes and consequences of micronutrient status on adiposity and comorbidities.

Screening for gestational diabetes mellitus and its prevalence in Bangladesh

BACKGROUND

The prevalence of gestational diabetes mellitus (GDM) has important health complications for both mother and child and is increasing all over the world. Although prevalence estimates for GDM are not new in developed and many developing countries, data are lacking for many low-income countries like Bangladesh.

OBJECTIVE

To evaluate the prevalence of GDM in Bangladesh.

RESEARCH DESIGN AND METHODS

This cross-sectional study included 3447 women who consecutively visited the antenatal clinics with an average gestation age of 26 weeks. GDM was defined according to WHO criteria (fasting plasma glucose [FPG] ≥7.0 mmol/L or 2-h ≥7.8 mmol/L) and the new ADA criteria (FPG ≥5.3 mmol/L or 2-h ≥8.6 mmol/L OGTT). We also calculated overt diabetes as FPG ≥7.0 mmol/L.

RESULTS

Prevalence of GDM was 9.7% according to the WHO criteria and 12.9% according to the ADA criteria in this study population. Prevalence of overt diabetes was 1.8%. Women with GDM were older, higher educated, had higher household income, higher parity, parental history of diabetes, and more hypertensive, compared with non-GDM women.

CONCLUSION

This study demonstrates a high prevalence of GDM in Bangladesh. These estimates for GDM may help to formulate new policies to prevent and manage diabetes.