Green synthesis of silver nanoparticles by microorganism using organic pollutant: its antimicrobial and catalytic application

A novel approach for the green synthesis of silver nanoparticles (AgNPs) from aqueous solution of AgNO₃ using culture supernatant of phenol degraded broth is reported in this work. The synthesis was observed within 10 h, and AgNPs showed characteristic surface plasmon resonance around 410 nm. Spherical nanoparticles of size less than 30 nm were observed in transmission electron microscopy. X-ray diffraction pattern corresponding to 111, 200, 220, and 311 revealed the crystalline nature of the as-formed nanoparticles. It was found that the colloidal solution of AgNP suspensions exhibited excellent stability over a wide range of ionic strength, pH, and temperature. The effect of pH and ionic strength indicated that stabilization is due to electrostatic repulsion arising from the negative charge of the conjugate proteins. The AgNPs showed highly potent antimicrobial activity against Gram-positive, Gram-negative, and fungal microorganisms. The as-prepared AgNPs showed excellent catalytic activity in reduction of 4-nitrophenol to 4-aminophenol by NaBH₄. By manufacturing magnetic alginate beads, the reusability of the AgNPs for the catalytic reaction has been demonstrated.     

Emission-based static traffic assignment models

Tailpipe emissions in the road transportation system are a major source of air pollution and greenhouse gases. One of the possible approaches is to influence drivers’ routing decisions such that the emissions and fuel consumption is minimized. In order to evaluate such condition, we develop environmental traffic assignment (E-TA) models based on user equilibrium (UE) and system optimal (SO) behavioral principles. Extending the traditional travel time-based UE and SO principles to E-TA is not straightforward because, unlike travel time, the rate of emissions increases with the increase in vehicle speed beyond a certain point. The results of various TA models show a network-wide traffic control strategy in which vehicles are routed according to SO-based E-TA, can reduce system-wide emissions. However, a system in which drivers make routing decisions to minimize their own emissions (E-UE system) results in a paradoxical situation of increased individual as well as system-wide emissions.     

Infrastructure development through PPPs in India: criteria for sustainability assessment

Public private partnerships (PPPs) allow the Indian Government to leverage private capital for meeting the widening demand-supply gap in the provision of infrastructure services. The private sector, however, prefers to limit the participation to financially attractive projects only, thereby resulting in patterns of infrastructure creation impeding the progress towards sustainable development. In order to promote sustainable development, the PPP procurement process should focus on incentivising the private sector for sustainable infrastructure development rather than concentrating on ensuring financial sustainability only. This paper discusses the principles-based PPP-specific framework that has been developed to facilitate assessment of PPP projects' progress towards sustainable development. The framework development was based on a holistic approach to sustainability assessment and subsequently validated through questionnaire survey with key stakeholders in the Indian PPP programme. This framework will provide the decision makers with appropriate decision aid for integration of sustainable development principles in the PPP procurement process.     

Reorienting Systematic Conservation Assessment for Effective Conservation Planning

Abstract: Systematic conservation assessment (an information‐gathering and prioritization process used to select the spatial foci of conservation initiatives) is often considered vital to conservation‐planning efforts, yet published assessments have rarely resulted in conservation action. Conservation assessments may lead more directly to effective conservation action if they are reoriented to inform conservation decisions. Toward this goal, we evaluated the relative priority for conservation of 7 sites proposed for the first forest reserves in the Union of the Comoros, an area with high levels of endemism and rapidly changing land uses in the western Indian Ocean. Through the analysis of 30 indicator variables measured at forest sites and nearby villages, we assessed 3 prioritization criteria at each site: conservation value, threat to loss of biological diversity from human activity, and feasibility of reserve establishment. Our results indicated 2 sites, Yiméré and Hassera‐Ndrengé, were priorities for conservation action. Our approach also informed the development of an implementation strategy and enabled an evaluation of previously unexplored relations among prioritization criteria. Our experience suggests that steps taken to ensure the closer involvement of practitioners, include a broader range of social data, encourage stakeholder participation, and consider the feasibility of conservation action can improve the relevance of assessments for conservation planning, strengthen the scientific basis for conservation decisions, and result in a more realistic evaluation of conservation alternatives.     

AHP-SWOT法在城市圈建设中耕地保护策略分析中的应用——以湖北赤壁为例

在实地调研湖北赤壁的基础上,探讨AHP-SWOT法在城市圈建设过程中的耕地保护策略分析中的应用.结果表明,耕地异地占补平衡是主要优势,耕地数量持续减少是主要劣势,新一轮土地利用总体规划是主要机遇,城市圈建设占用耕地是主要威胁,建议赤壁市在城市圈建设过程中应发挥耕地异地占补平衡优势,回避城市圈建设占用耕地的威胁.     

PULSE,progressive upper level set scan statistic for geospatial hotspot detection

This paper presents a scan statistic, progressive upper level set (PULSE) scan statistic, for geospatial hotspot detection and its software implementation. Like ULS, the PULSE scan statistic is based on the arbitrarily shaped scan window and can be adapted for a network setting. PULSE is a refinement of the upper level set (ULS) scan statistic. Like some other likelihood based scanning devices, the ULS scan statistic identifies maximum likelihood estimate (MLE) zones that tend to be ‘stringy’ and sprawling. Its search path increases possibility of inclusion of extraneous cells in its MLE zones and, to a smaller extent, of exclusion of cells that belong to a true hotspot from its MLE zone. The PULSE scan statistic achieves improvement over the ULS scan statistic in two ways. First, it begins its search for a most likely zone with a large population of candidate zones obtained by modifying the ULS tree structure and continues its search using a genetic algorithm. Secondly, to reduce chances of generating an MLE that is excessively stringy and that includes extraneous cells in the MLE zone, PULSE uses cardinality and compactness of zones along with their likelihoods as the fitness function in the genetic algorithm and uses several pertinent criteria including evenness of intra-zone cellular response ratios to determine the MLE zone. To reduce computation, Gumbel distribution of extreme values is used to determine the p-value of the MLE zone. Better results come at the cost of increased processing time. An evaluative performance study is presented.     

Green synthesis of symmetrical N, N′-disubstituted thiourea derivatives in water using solar energy

Thioureas are of importance in medicinal chemistry due to their biological activities such as antituberculosis, anti-HIV, analgesic, anti-inflammatory, antimicrobial, antiarrhythmic, fungicide, herbicides, rodenticides and as phenoloxidase enzymatic inhibitors. Treatment of primary and secondary amines with thiophosgene is the common method of making symmetrical disubstituted thioureas. However, this method is hazardous due to the toxic properties of thiophosgene. Here, we report a green, operationally simple approach for the synthesis of 1, 3-disubstituted thiourea derivatives in moderate to excellent yields of 57–99 %. We use primary amines and CS₂ in water without any catalyst and solar thermal energy. This method is more environmentally benign and energy-saving compared with previously reported methods.     

Assessment of drinking water quality using ICP-MS and microbiological methods in the Bholakpur area,Hyderabad, India

A total of 16 people died and over 500 people were hospitalized due to diarrhoeal illness in the Bholakpur area of Hyderabad, India on 6th May 2009. A study was conducted with immediate effect to evaluate the quality of municipal tap water of the Bholakpur locality. The study consists of the determination of physico-chemical properties, trace metals, heavy metals, rare earth elements and microbiological quality of drinking water. The data showed the variation of the investigated parameters in samples as follows: pH 7.14 to 8.72, EC 455 to 769 μS/cm, TDS 303.51 to 515.23 ppm and DO 1.01 to 6.83 mg/L which are within WHO guidelines for drinking water quality. The water samples were analyzed for 27 elements (Li, Be, B, Na, Mg, Al, Si, K, Ca, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Ba and Pb) using inductively coupled plasma-mass spectrometry (ICP-MS). The concentrations of Fe (0.12 to 1.13 mg/L), Pb (0.01 to 0.07 mg/L), Cu (0.01 to 0.19 mg/L), Ni (0.01 to 0.15 mg/L), Al (0.16 to 0.49 mg/L), and Na (38.36 to 68.69 mg/L) were obtained, which exceed the permissible limits of the World Health Organization (WHO) for drinking water quality guidelines. The remaining elements were within the permissible limits. The microbiological quality of water was tested using standard plate count, membrane filtration technique, thermotolerant coliform (TTC), and most probable number (MPN) methods. The total heterotrophic bacteria ranged from 1.0 × 10⁵ to 18 × 10⁷ cfu/ml. Total viable bacteria in all the water samples were found to be too numerable to count and total number of coliform bacteria in all water samples were found to be of order of 1,100 to >2,400 MPN index/100 ml. TTC tested positive for coliform bacteria at 44.2°C. All the water samples of the study area exceeded the permissible counts of WHO and that (zero and minimal counts) of the control site (National Geophysical Research Institute) water samples. Excessively high colony numbers indicate that the water is highly contaminated with microorganisms and is hazardous for drinking purposes. Bacteriological pollution of drinking water supplies caused diarrhoeal illness in Bholakpur, which is due to the infiltration of contaminated water (sewage) through cross connection, leakage points, and back siphoning.     

Identifying the largest individual sample value from a two-way composite sampling design

Composite sampling techniques for identifying the largest individual sample value seem to be cost effective when the composite samples are internally homogeneous. However, since it is not always possible to form homogeneous composite samples, these methods can lead to higher costs than expected. In this paper we propose a two-way composite sampling design as a way to improve on the cost effectiveness of the methods available to identify the largest individual sample value.     

Estimation of air pollutant emission loads from construction and operational activities of a port and harbour in Mumbai, India

Port causes environmental and health concerns in coastal cities if its operation and development are not made environmentally compatible and sustainable. An emission inventory is necessary to assess the impact of port projects or growth in marine activity as well as to plan mitigation strategies. In this study, a detailed emission inventory of total suspended particulate (TSP) matter, respirable particulate matter (PM₁₀), sulphur dioxide (SO₂) and oxides of nitrogen (NO_x) for a port having operation and construction activities in parallel is compiled. The study has been done for 1 year. Results show that the maximum contribution of emission of air pollutants in the port area was from TSP (68.5%) and the minimum was from SO₂ (5.3%) to the total pollutants considered in this study. Total TSP emission from all activities of the port was 4,452 tyr^???1 and PM₁₀ emission was 903 tyr^???1 in the year 2006. Re-suspension of dust from paved roads was the major contributor of TSP and PM₁₀ in the road transport sector. Construction activities of the port had contributed 3.9% of TSP and 7.4% of PM₁₀ to total emission of particulate matter. Of the total particulate emissions from various port activities approximately 20% of TSP could be attributed to PM₁₀. The sectoral composition indicates that major contribution of SO₂ emission in the port was from maritime sector and major contribution of NO_x was from road transport sector.