Air pollution tolerance index of Mangifera indica plant species growing in the greater Dhaka region, Bangladesh

Air pollution tolerance index (APTI) of the mango (Mangifera indica) leaves growing in the greater Dhaka region, Bangladesh was studied. Leaf samples were collected in winter season from both roadsides and residential locations of different parts of greater Dhaka region. The APTI values of the leaves were calculated from the total chlorophyll content (TCC), ascorbic acid concentration, relative water content (RWC), and pH of the leaf extract. Determined APTI values were compared with Particulate Matter (PM2.5) values in each sampling location. TCC and ascorbic acid concentration were determined with a UV-Visible spectrophotometer. TCC values varied between 0.25 and 1.10 mg/g with an average of 0.66 mg/g. The average concentration of ascorbic acid was 2.21 mg/g (values ranging from 0.33 to 3.24 mg/g) and the RWC varied from 81.5% to 97.4%. Moreover, pH values of the leaf extracts were found acidic (4.48-5.78). The average APTI values varied depending on the locations with a total average of 10.1. However, the average APTI value in the residential area (10.5) was slightly higher compared to roadsides (9.70) indicating the existence of high-level pollutions at the roadsides. The highest APTI value was observed in Dhaka city sampling location (10.6) where the lowest value was found in Narayangonj (9.70). APTI values showed a strong correlation with particulate matter concentrations (PM2.5). These results suggest that Mangifera indica is very sensitive to the air pollutants. J. Biodivers. Conserv. Bioresour. Manag. 2019, 5(1): 1-12

Comparative efficiency of wheat straw and sugarcane bagasse biochar reduces the cadmium bioavailability to spinach and enhances the microbial activity in contaminated soil

Biochar is considered a novel soil amendment for cadmium (Cd) stabilization in contaminated soils. A pot experiment was conducted to examine the efficiency of wheat straw and sugarcane bagasse induced biochar on Cd mobility in soil and its bioavailability to spinach in contaminated soil. Soil pH, Cd contents in plant tissues and microbial biomass were examined. Results showed that Cd was significantly decreased by 30.95% and 20.83% with wheat straw and sugarcane bagasse biochar at 2% application rate respectively, relative to the control. Similarly, Cd contents were decreased in plants shoots by 15.41 and 14.33%, while in roots by 48.3 and 35.54%, when wheat straw and sugarcane biochar were added at 2% application rate respectively. Moreover, soil microbial biomass was significantly increased with the application of all biochar types and their applications rates. Finally, wheat straw biochar at 2% application rate can be considered as an effective approach for Cd stabilization in contaminated soils.

Evaluation of Training Session Applying Gagne’s Events of Instructions

Background: This study explores the effectiveness of educator's training programs regarding the presentation, materials, facilities, relevance and usefulness of the training to the current employment and facilitator’s knowledge using Gagne’s event of instructions. Method: A half day long training was conducted on September 2017 at reach of the two health care teaching institutes. At the end of training, evaluation was done and rated in 5 point Likert scale with 5 as the highest score. Participants agreed that the training was useful and relevant to their work. Result: This study showed a positive perception of the learners which will help their job performance as well as the outcome of their dental teaching school and Gagne’s Events of Instructions can be used when conducting this type of training sessions. Conclusion: Regular training program for staff development need to be carried out following a system approach with right mix of input and contents which process with right sequences of instructions to fill the gap between desired performance and actual staff performance. Bangladesh Journal of Medical Science Vol.18(3) 2019 p.552-556

Rice straw- and rapeseed residue-derived biochars affect the geochemical fractions and phytoavailability of Cu and Pb to maize in a contaminated soil under different moisture content

Management of toxic elements contaminated upland and wetland soils using biochar is of great concern from both agricultural and environmental points of view. The impact of rice straw- and rapeseed residue-derived biochars produced under 300 °C and 550 °C (added to the soil at 2% and 5%; w/w) on the geochemical fractions, phytoavailability, and uptake of Cu and Pb in a contaminated mining soil under different moisture contents (80%, 60%, and 40% of soil field capacity) was investigated in a greenhouse pot experiment using maize. The higher rate of rice straw-derived biochar pyrolyzed at 550 °C caused a significant reduction in the mobile (soluble + exchangeable) fraction of Cu (59.42%) and Pb (75.4%) and increased the residual fractions of Cu (37.8%) and Pb (54.7%) in the treated soil under the highest moisture content (80%) as compared to the untreated soil. Therefore, this biochar significantly decreased the phytoavailability (CaCl₂-extractable form) of Cu by 59.5% and Pb by 67.6% under the highest moisture content. Also, at the same moisture level (80%), the higher rate of rapeseed residue-derived biochar pyrolyzed at 550 °C decreased significantly the phytoavailability of Cu by 46.5% and Pb by 60.52% as compared to the untreated soil. The 5% rate of the higher temperature pyrolyzed rice straw and rapeseed biochars decreased the uptake of Cu and Pb by the roots and shoots of maize up to 51% for Cu and 45% for Pb. Immobilization of Cu and Pb in the biochar-treated soil at 80% moisture content may possibly due to the associated increase of soil pH and poorly-crystalline Fe oxides content, and/or the metals precipitation with sulfides. These results indicated that application of high temperature pyrolyzed rice straw- and rapeseed residue-derived biochars at 5% could immobilize Cu and Pb and decrease their uptake by maize under high levels of moisture content; consequently, they can be used for phyto-management of Cu and Pb contaminated wetland soils.

Assessing risk to human health for heavy metal contamination through street dust in the Southeast Asian Megacity: Dhaka, Bangladesh

Contaminants in road dusts can directly pose significant human health risks through oral ingestion, particle inhalation, and dermal contact. Therefore, this study has been designed to analyze heavy metal contaminations in 88 street dusts collected from the 22 high traffic sites and industrial areas of the Southeast Asian Megacity: Dhaka (capital of Bangladesh) using energy dispersive X-ray fluorescence (EDXRF) spectroscopy. This study revealed that the maximum Pb, Cd, Zn, Cr, Ni, As, Mn and Cu contents in the street dust samples were 18.9, 11.6, 239.2, 144.3, 37.1, 8.1, 261.5 and 49.6 mg/ kg respectively in which Ni and Pb concentration were 2 times, and Cd concentration was 200 times higher than the background level in soil; and As concentration was slightly higher than soil background level. The spatial distribution of heavy metal concentrations in street dust samples in Dhaka City was revealed that the hot spot areas of Pb, Ni, Cd and As were mainly associated with heavy traffic and industrial activities. The risk assessment strategies were used for this study for identifying the routes of exposure through oral ingestion, inhalation, and dermal contact by the fine particles (~75 μm) of street dust, especially for children based on the US EPA health risk models. Both non-carcinogenic and carcinogenic risks of heavy metals were characterized in street dust samples. Results based on the hazard index (HI), in the case of non-cancer effect, the ingestion of dust particles of children and adults in Dhaka City appeared to be the route of exposure to street dust that results in a higher risk for heavy metals, followed by dermal contact. This study revealed that the inhalation of re-suspended particles through mouth and nose were almost negligible. It was also noticed that children were experiencing the potential health risk due to HI for Cr (1.04), which was slightly higher than the safe level 1, and Cd (0.69) was close to the safe level 1. Reversely, cancer risk for Cr (i.e. 4.27 × 10^-6) was fallen within the range of threshold values (10^-4 to 10^-6) and As (i.e. 9.59 × 10^-7) was close to the upper limit of threshold values (10^-4 to 10^-6).

Near-Zone Mediation of RET by One and Two Proximal Particles

The effect of two inert, electric dipole polarizable molecules in relaying electronic excitation energy resonantly between a donor-acceptor pair is studied within the framework of molecular QED theory. Since transfer is efficacious when the coupled particles are close to one another, the matrix element is calculated in the near-zone approximation by employing static dipolar interaction potentials and third-order diagrammatic perturbation theory. For isotropic species, the Fermi golden rule exchange rate exhibits a Förster-like inverse sixth power dependence on each pair separation distance, is proportional to the modulus squares of the transition electric dipole moments of donor and acceptor, and depends on the polarizabilities of the two mediators. Comparison is made with direct (2-body) and third-body mediated near-zone transfer. Matrix elements for these last two processes are used to evaluate contributions to the rate due to 2-body-3-body, 2-body-4-body, and 3-body-4-body interference terms. In each of these cases, an inverse cubic dependence on each of the relative particle displacements is found.

Effective Role of Biochar, Zeolite and Steel Slag on Leaching Behavior of Cd and Its Fractionations in Soil Column Study

Remediation of cadmium (Cd) from contaminated soils is considered a complicated task of environmental safety. A column leaching experiment was planned to estimate the influence of biochar (BC), zeolite (ZE) and steel slag (SL) at 1.5% and 3% application rate on Cd leaching behavior and chemical fractionation in contaminated soil. A sequential extraction procedure, the European Community Bureau of Reference (BCR), Toxicity Characteristic Leaching Procedure (TCLP) and NH₄NO₃ were performed after leaching was completed. The soluble portion of Cd was decreased by 36.3%, 18.4% and 28.7% and Cd contents in leachate were decreased by 44.8%, 30% and 31.3% after BC, ZE and SL addition at 3% rate, respectively over control soil. The greater reduction in TCLP extractable Cd was observed by 29.6% with BC and 22.4% with ZE and 25.7% with SL at 3% application rate. Overall, biochar can be considered an efficient soil amendment to reduce Cd leaching as well as increased its stabilization within soil profile.

Particulate matters and gaseous pollutants in indoor environment and Association of ultra-fine particulate matters (PM1) with lung function

Real-time particulate matters (PM₁, PM_2.5, PM₄, PM₇, PM₁₀, and TSP) with AEROCET 531S (USA), gaseous pollutants (NO₂ and TVOC) with Aeroquel 500 gas sampler (NZ) were measured from the indoor air of houses at four residential locations in Dhaka, Bangladesh. PM₁₀ samples were collected on quartz filters with a dual channel dust sampler (IPM-FDS 2510, India) for selected trace metal determination from five houses of Dhaka. Respiratory function of the occupants was assessed by using a peak expiratory flow meter (Rossmax PF 120). Mean PM₁, PM_2.5, and PM₁₀ concentrations were 46.1 ± 13.4, 76.0 ± 16.2, and 203.9 ± 44.8 μg m^-3, respectively. Higher enrichment factors of Pb, Zn, and Ni were found for traffic, industrial, and constructional activities. The correlation between indoor and outdoor PM_2.5 (R² = 0.42) and ratios (I/O < 1) suggesting indoor air was effected by outdoor air. The concentration of NO₂ (0.076 ± 0.007 ppm) and TVOC (90.0 ± 46.0 ppm) was found above than other studies. The average total hazard ratio (THR) in Dhaka was 9.06 and has the highest exposure to air pollutants (PM_2.5, PM₁₀, NO₂) in Khilkhet (THR 10.1) residents. A negative association between ultra-fine particles (PM₁) and peak flow rate measurements of the residents living in these houses indicates that inhalations of ultra-fine particles has great influence on the reduced lung efficiency.

Technical Varieties of Ross Procedure: A Case Series

Replacement of aortic valve with the pulmonary autograft is carried out through the Ross procedure due to its potential for growth, durability in pediatric population, and absence of anticoagulation. This case series reports the postoperative outcome of two technical variations of Ross procedure in eight patients who underwent surgery from January 2007 to December 2016. The dominant valvular hemodynamic indication was aortic regurgitation. The techniques employed for Ross procedure included free standing root replacement in six patients and modified root replacement with autograft stabilisation using Dacron interposition graft in two patients. Right ventricular outflow tract (RVOT) conduit reconstruction was achieved by utilisation of Contegra bio prosthesis in four patients; and use of manually constructed valved conduit comprising of PTFE (polytetrafluoroethelene) membrane and bovine pericardial tube in remaining four patients. There was no mortality and no re-intervention. The technical varieties of Ross procedure offer freedom from need of anti-coagulation, mortality, and RVOT conduit failure in younger adults.

Photochemical degradation affects the light absorption of water-soluble brown carbon in the South Asian outflow

Light-absorbing organic aerosols, known as brown carbon (BrC), counteract the overall cooling effect of aerosols on Earth's climate. The spatial and temporal dynamics of their light-absorbing properties are poorly constrained and unaccounted for in climate models, because of limited ambient observations. We combine carbon isotope forensics (δ¹³C) with measurements of light absorption in a conceptual aging model to constrain the loss of light absorptivity (i.e., bleaching) of water-soluble BrC (WS-BrC) aerosols in one of the world's largest BrC emission regions-South Asia. On this regional scale, we find that atmospheric photochemical oxidation reduces the light absorption of WS-BrC by ~84% during transport over 6000 km in the Indo-Gangetic Plain, with an ambient first-order bleaching rate of 0.20 ± 0.05 day^-1 during over-ocean transit across Bay of Bengal to an Indian Ocean receptor site. This study facilitates dynamic parameterization of WS-BrC absorption properties, thereby constraining BrC climate impact over South Asia.

Coping Strategies among First and Third Year Medical Students in a Malaysian Public University

Background: Medical students lead a stressful life and therefore the coping strategy is very important for them to alleviate the stress. The objective of this study was to explore the coping strategy among the first year and third year medical students and also to identify any significant difference between genders and study-years. Materials & methods: This cross-sectional study involved first and third year medical students of University Kebangsaan Malaysia of session 2013/2014. Coping strategy was explored using the ‘Coping Inventory for Stressful Situations’ (CISS) which consist of 48-items where 16 under task-oriented, 16 under emotional-oriented and 16 under avoidance-oriented coping. A five-point Likert’ scale ranging from ‘1=not at all’ to ‘5=very much’ was used to rate the items. Results: Task oriented coping was found the most common strategy among all students while emotion oriented was the least. First year students scored significantly higher than third year showing their best effort to adapt a new environment with insignificant difference between genders. Conclusions: Task-oriented coping strategy of the students is a good sign of problem solving skills. Though majority of the students adapt this method of coping, still there are other methods in practice. Medical school should focus for growing awareness about the positive coping methods in response to stress. This is necessary for the long term benefit of the students as well for better service to the nation. J MEDICINE JUL 2019; 20 (1) : 5-11 

Global Sources of Fine Particulate Matter: Interpretation of PM2.5 Chemical Composition Observed by SPARTAN using a Global Chemical Transport Model

Exposure to ambient fine particulate matter (PM_2.5) is a leading risk factor for the global burden of disease. However, uncertainty remains about PM_2.5 sources. We use a global chemical transport model (GEOS-Chem) simulation for 2014, constrained by satellite-based estimates of PM_2.5 to interpret globally dispersed PM_2.5 mass and composition measurements from the ground-based surface particulate matter network (SPARTAN). Measured site mean PM_2.5 composition varies substantially for secondary inorganic aerosols (2.4-19.7 μg/m³), mineral dust (1.9-14.7 μg/m³), residual/organic matter (2.1-40.2 μg/m³), and black carbon (1.0-7.3 μg/m³). Interpretation of these measurements with the GEOS-Chem model yields insight into sources affecting each site. Globally, combustion sectors such as residential energy use (7.9 μg/m³), industry (6.5 μg/m³), and power generation (5.6 μg/m³) are leading sources of outdoor global population-weighted PM_2.5 concentrations. Global population-weighted organic mass is driven by the residential energy sector (64%) whereas population-weighted secondary inorganic concentrations arise primarily from industry (33%) and power generation (32%). Simulation-measurement biases for ammonium nitrate and dust identify uncertainty in agricultural and crustal sources. Interpretation of initial PM_2.5 mass and composition measurements from SPARTAN with the GEOS-Chem model constrained by satellite-based PM_2.5 provides insight into sources and processes that influence the global spatial variation in PM_2.5 composition.

Empathy among undergraduate medical students: A cross-sectional study in one Malaysian public medical school

Background

Empathy is one of the cardinal components for physician-patient relationships, optimal outcomes in patient care, improved patient satisfaction, greater adherence to therapy, and lower malpractice liability. It is also considered an essential quality for health-care professionals to practice medicine. The aim of the present study was to assess the empathy level of medical students of Universiti Pertahanan Nasional Malaysia (UPNM) National Defense University of Malaysia, Kuala Lumpur, Malaysia.

Methods

This was a cross-sectional study conducted in 2017 which recruited medical students of UPNM. The Empathy Quotient, a self-reported questionnaire, was utilized for data collection. The total empathy score of the questionnaire is 80.

Results

Majority of the respondents were male (60.9%), year-V students (26.6%), Malay (70.5%), and cadet officer (69.6%). The overall mean score achieved by the respondents was 36.76 ± 9.18, and 74.4% of the respondents scored more than 30. The empathy scores of the students were significantly affected by the gender (t = 2.371; df = 205; P < 0.05), year of study (F = 2.553; df = 4/202; P < 0.05), and examination grades (F = 3.488; df = 2/204; P < 0.05). The findings showed that female students are more empathetic than their male counterparts. Further, the post hoc Tukey test analysis revealed that Year-V students are more empathetic than their junior counterparts and students who got highest grade are more empathetic.

Conclusions

To improve the empathy level of the UPNM medical students, appropriate educational strategies and interventions should be designed and implemented in the curriculum to inculcate, maintain, and enhance empathy.

Analysis of Problems Posed in Problem Based Learning Cases: Nature, Sequence of Discloser and Connectivity with Learning Issues

Background: Problems posed in problem based learning (PBL) cases used during pre-clinical teaching-framework are typically a set of descriptions of events in need of explanations and resolution. The objectives of this study were to analyze the problems in PBL cases aimed to suggest areas for improvement.Methods: It was a review of cases used in PBL in undergraduate medical curriculum at UKM Medical Centre. Problems in PBL cases were labeled as ‘Triggers’ and ‘Patient Information Sheets’ which were disclosed as prescribed in structured facilitators’ guide. Six of the 10 PBL cases used in semester-1, session 2013-2014 were selected randomly for analysis.Results: Problems in 50% cases were overloaded and in 50% cases sequences of problem-disclosure were disorderly-labeled, though the flow of descriptions were alright. Averagely, 82% faculty-intended learning issues prescribed in facilitators’ guide were connected with problems. Unconnected learning issues were the result of faculty directed teacher-centered approach of guidance, while important learning issues that could have been derived against problems were un-identified.Conclusion: Connectivity of average 82% faculty-intended learning issues with problems reflect as good quality of PBL problems in UKM Medical Centre. However, problem disclosers in disorderly-labeled fashion, unconnected and unidentified issues against some problems in spite of conducting a good numbers of faculty development workshops, raised the issue of needs of further research on standard of training workshops. Educational leaders should give due importance on professionalism and needs of high-quality training for faculty to enhance PBL skills either by utilizing and mobilizing existing properly trained faculty or by hiring appropriate trained faculty.Bangladesh Journal of Medical Science Vol.17(3) 2018 p.417-423

Perspective: Quantum Hamiltonians for optical interactions

The multipolar Hamiltonian of quantum electrodynamics is extensively employed in chemical and optical physics to treat rigorously the interaction of electromagnetic fields with matter. It is also widely used to evaluate intermolecular interactions. The multipolar version of the Hamiltonian is commonly obtained by carrying out a unitary transformation of the Coulomb gauge Hamiltonian that goes by the name of Power-Zienau-Woolley (PZW). Not only does the formulation provide excellent agreement with experiment, and versatility in its predictive ability, but also superior physical insight. Recently, the foundations and validity of the PZW Hamiltonian have been questioned, raising a concern over issues of gauge transformation and invariance, and whether observable quantities obtained from unitarily equivalent Hamiltonians are identical. Here, an in-depth analysis of theoretical foundations clarifies the issues and enables misconceptions to be identified. Claims of non-physicality are refuted: the PZW transformation and ensuing Hamiltonian are shown to rest on solid physical principles and secure theoretical ground.

Molecular characterization and multidisciplinary management of Gerbich hemolytic disease of the newborn

Gerbich (Ge) antigens are high frequency red cell antigens expressed on glycophorin C (GYPC) and glycophorin D. Hemolytic disease of the fetus and newborn (HDFN) due to Gerbich antibody is rare and presents a clinical challenge, as Gerbich negative blood is scarce. We report a case of HDFN due to maternal Ge3 negative phenotype and anti-Ge3 alloimmunization, successfully managed by transfusion of maternal blood. Molecular testing revealed that the mother has homozygous deletion of exon 3 of GYPC, the father is homozygous wildtype for GYPC, and the infant is obligate heterozygote expressing Ge3.

Starch Derivatives that Contribute Significantly to the Bonding and Antibacterial Character of Recycled Fibers

The objective of the current research was to fabricate and explore the ability of a renewable resource-based paper strength agent to enhance fiber-fiber bonding and introduce antibacterial properties to recycled fiber paper sheets. The agent corn starch, was modified with diethylenetriamine pentaacetic acid (DTPA), complexed with chitosan, and added to recycled furnishes to provide a plethora of hydrogen bonding sites predicated by acid groups, hydroxyls, and amines. The goal was two-fold: (1) to not only increase interfiber bonding, but (2) afford antibacterial character. The modified corn starch was characterized in previous work by thermal gravimetric analysis, differential scanning calorimeter, and Fourier transform infrared spectroscopy. The recycled pulp slurry was mixed with a ∼1.5% modified starch/chitosan agent before manufacturing a two-dimensional paper substrate that was subjected to mechanical testing. The burst, STFI compressive strength, tensile, and interfiber bonding strength increased 48.8, 49.5, 49.9, and 176%, respectively, while significantly increased gloss was obtained despite slightly diminished tear and roughness. The antibacterial character of these substrates was confirmed by the substrates displaying a 97% bacteria kill rate.

Cadmium Immobilization Potential of Rice Straw-Derived Biochar, Zeolite and Rock Phosphate: Extraction Techniques and Adsorption Mechanism

Heavy metal contamination in agricultural soils has become a serious environmental concern due to their generally high mobility and toxic effects on plants and food security. An incubation study was conducted to assess the effectiveness of biochar (BC), zeolite (ZE) and rock phosphate (RP) stabilizers on the immobilization of cadmium (Cd) in contaminated soils. Various extraction techniques were carried out: a sequential extraction procedure, the European Community Bureau of Reference (BCR), the toxicity characteristics leaching procedure (TCLP) and extraction with ammonium nitrate. In addition, Cd adsorption by these materials was observed using Langmuir and Freundlich isotherms. The results showed that with an increase in soil pH the exchangeable fraction of Cd in soil was significantly reduced by 28%-29.4%, 9%-13% and 4%-14% for BC, ZE, and RP, respectively. According to the Langmuir adsorption isotherm, BC-amended soil showed a higher adsorption capacity (Q_m) of Cd from 8.38 to 19.85 mg g^-1. Overall, BC offered better results when compared to other amendments.

Chemical characterization of PM2.5 collected from a rural coastal island of the Bay of Bengal (Bhola, Bangladesh)

This work focuses on the chemical characterization of fine aerosol particles (PM_2.5) collected from a rural remote island of the Bay of Bengal (Bhola, Bangladesh) from April to August, 2013. PM_2.5 particle-loaded filters were analyzed for organic carbon (OC), elemental carbon (EC), water-soluble ions, and selected saccharides (levoglucosan, mannosan, galactosan, arabitol, and mannitol). The average PM_2.5 mass was 15.0 ± 6.9 μg m^-3. Organic carbon and elemental carbon comprised roughly half of the analyzed components. Organic carbon was the predominant contributor to total carbon (TC) and accounting for about 28% of PM_2.5 mass. Secondary organic carbon (SOC) was inferred to be ~ 26% of OC. The sum of ions comprised ~ 27% of PM_2.5 mass. The contribution of sea salt aerosol was smaller than expected for a sea-near site (17%), and very high chloride depletion was observed (78%). NssSO₄^2- was a dominant ionic component with an average concentration of 2.0 μg m^-3 followed by Na⁺, NH₄⁺, and nssCa²⁺. The average concentration of arabitol and mannitol was 0.11 and 0.14 μg m^-3, respectively, while levoglucosan and its stereoisomers (mannosan and galactosan) were bellow detection limit. NH₄⁺/SO₄^2- equivalent ratio was 0.30 ± 0.13 indicating that secondary inorganic aerosol is not the main source of SO₄^2-. Enrichment factor (EF) analysis showed that SO₄^2- and NO₃^- were enriched in atmospheric particles compared to sea aerosol and soil indicating their anthropogenic origin. Higher OC/EC ratio (3.70 ± 0.88) was a good indicator of the secondary organic compounds formation. Other ratios (OC/EC, K⁺/EC, nssSO₄^2-/EC) and correlation analysis suggested mixed sources for carbonaceous components. Arabitol and mannitol both showed strong correlation with EC having R ² value 0.89 and 0.95, respectively. Air mass trajectories analysis showed that concentrations of soil and anthropogenic species were lower for air masses originating from the sea (May-August) and were higher when air came from land (April).