Integrated waste management has been widely accepted as a sustainable approach, and is applicable to solid waste management system in any region. Developed and developing countries, however, undertake different approaches to develop the integrated waste management system. Due to limited data availability, unskilled workforce, financial constraints and lack of expertise in developing countries, the decisions are often based on presumptions rather than objective judgments. Selecting and combining different actions according to the precise requirements of the waste management situation in developing countries and understanding how a specific decision choice fits in a local context is key to identifying sustainable solutions. The study undertook a combined Life cycle assessment (LCA) and Life cycle costing (LCC) approach under the same system boundaries; the objective was to establish the most environmentally and economically feasible alternative for the study area, through comparisons of different waste management scenarios. The scenarios were designed and tested in a life cycle perspective, using a computer based model ―EaseTech‖. All relevant technical and non-technical aspects of existing solid waste management system in Bahawalpur City were determined while the informal sector was also given due consideration in the study. Waste characterization study carried out for one year in ―Bahawalpur‖ city showed significant difference between collected waste (0.274 kg/cap/day) and waste generation rates (0.424 kg/cap/day) due to high source separation activities. Waste generation rates were reported to vary considerably with income groups and seasons. The waste composition analysis revealed organic waste as the largest contributor of household solid waste in Bahawalpur including food waste (44.75%), yard waste (8%), animal excreta (3.6%) and diapers (7.2%), followed by recyclables (27%) including paper (5.9%), cardboard (6.4%), hard plastics (5.36%), soft plastics (2%), glass (3.4%) and metals (1.8%), while the share of inerts including soil and ash is also considerable (9%). From the generated 282.2 tons of waste/day, 58 tons have been minimized at household level. 157 tons of the waste are collected and openly dumped by municipality workers, while remaining lies on the streets or road corners. High scavenging of organic waste and recyclable in Bahawalpur retrieves almost 64 tons of waste daily including 22.6 tons of recyclables. The informal sector in the area is robust. Their societal, economic, environmental and health impacts were studied and weighed for related outcomes. Field surveys revealed that waste pickers are socially marginalized with limited access to the necessities of life, including health services. The study showed a high prevalence of Hepatitis B & C infection in waste pickers (4% & 28%) as compared to non-waste pickers (2% & 6%). The higher incidence of Hepatitis among waste pickers is a function of their occupation involving exposure to sharps and needle stick injuries during waste collection with bare hands. The study acknowledged that the informal waste management sector effectively reduces waste, contributes to the conservation of natural resources and mitigates greenhouse gas emissions while it is proficiently involved in waste recovery activities as well; however, their significant role and aptitude in the supply chain has usually been underestimated. To achieve waste management system sustainability in the study area an important implication is to investigate formal-informal waste management sector integration possibilities. The existing situation and proposed solutions for formal-informal waste sector integration was discussed under a recently developed tool known as ―InteRa‖ (integration radar) rapid evaluation metric and visualization tool. Application of ―InteRa‖ framework illustrated the extent to which local situation is favorable and advocated changes that need to be incorporated to achieve integration in the study area. The baseline scenario depicted the current waste management situation; suggested scenarios were based on four main assumptions, including data collection on waste composition and source separation, use of simple sanitary landfills, organic waste separation for treatment and formal participation of scavengers in the waste management sector. First three scenarios referred to short-range solutions (SRS 1,2 & 3) while scenario 4, 5 & 6 depicted long-standing solutions (LSS). SRS 1 assumed composting of organic waste, while SRS 2 and 3 assumed that gathered waste follows the incineration and refuse derived fuel (RDF) incineration‘s route with energy recovery. LSS 4, 5 & 6 considered the possible integration of formal and informal waste management system with increased collection efficiency. LSS 4 considered material recovery facility (MRF) for recyclable recovery and diversion of organic waste to anaerobic digestion, while LSS 5 and 6 considered the addition of mechanical biological treatment for sorting of waste into different waste fractions and subsequent treatment using RDF incineration. EaseTech calculated environmental impacts of different scenarios for seven impact categories including climate change (CC), human toxicity-carcinogenic (HT-C), human toxicity-non carcinogenic (HT-NC), ecotoxicity-total (EcT), depletion of abiotic resourcesreserve (DAR-R), depletion of abiotic resources-fossil (DAR-F) and particulate matter (PM). The results depict a representation of the input data and relied upon modeled inventory for each process used in the scenarios. The evaluation of the net environmental impacts showed that for SRS, scenario 2 performed in the most environmentally friendly way in five of the seven impact categories except for DAR-R and EcT categories. The baseline scenario reacted better than the other three scenarios in DAR-R category, while worst in EcT category. Scenario 1 appeared to be the worst environmental scenario with most loadings in four (HTC, HT-NC, DAR-R, DAR-F) out of seven categories. While scenario 3 showed better environmental results for ECT and worst for CC and PM categories. In comparison to LSS the baseline scenario appeared to be the best in three categories (HT-NC, DAR-R & PM). Scenario four presented the best environmental performance for only on category i-e; climate change. Scenario 5 appeared to be the worst scenario for PM category and best for HT-C impact category. Scenario 6 contributed most loads in only 1 impact category (CC), performed better than scenario 4 in five impact categories (HT-C, HT-NC, EcT, DAR-R and DAR-F), while presented less loadings than scenario 5 in three impact categories (DAR-R and DAR-F & PM). For HT-C and EcT categories the loadings attributed by scenario 5 and 6 are almost same. The cost analyses for different scenarios were based on the financial calculations of different elements used in these scenarios. The economic evaluation of the entire system showed that the baseline scenario with more manual work and less involvement of technology is cost effective. The second scenario (incineration + energy recovery) was found to be the most revenue generating due to electricity generation and its sale to the grid, while scenario one and three were also found to be economically beneficial nevertheless they are more expensive than the baseline scenario. Reasons include involvement of advanced technology for the collection and transportation of waste and different treatment options including composting, RDF incineration and sanitary landfilling. Among LSS, scenario four is an economically sound option while scenario five is the most expensive one; scenario 6 is interestingly found to have almost equal revenue and expense. The costs of the system are found to increase with increased complexity of the system. The comparative analysis suggests scenario 2 as the best waste management choice among short term scenarios while scenario 6 as the most rational alternative for the study area in long term perspective.
Growth factors are the potential operational members which control different phases of liver regeneration. Different growth factors have expression regulation in the whole process relating to different phases of liver regeneration. Objective: To assess the expression regulation of different growth factors and cytokines involved in liver regeneration in a phase-dependent manner. Methods: Blood and liver samples were collected and analyzed on 1st, 3rd, 5th, 7th and 14th postoperative days after 50% Partia hepatectomy (PHx). Results: Steady increase of liver regeneration rate was recorded from 90.8% (1st day) to 97.9% (7th day). Liver function tests further confirmed the steady liver recovery in PHx mice. Several growth factors such as HGF and VEGF exhibited an up-regulation till 5th day and later gradual decrease till 14th day compared to control mice. Albumin, CK18 and CK19 showed sequential expression increase from 1st to 14th day compared to AFP and HNF-4α upregulated until 5th and 1st day, respectively. Quantification of these growth factors further confirm our results. Conclusions: Conclusively, these results highlight a phase-dependent regulation and role of growth factors in liver regeneration and recovery
A study of the photolysis of cyanocobalamin (vitamin B12) (B12), aquocobalamin (B12a) and hydroxocobalamin (vitamin B12b) (B12b) in the presence of ascorbic acid (vitamin C) (AH2) has been carried out in the pH range 2.0-12.0 using a visible radiation source. It involved the development of a multicomponent spectrophotometric method for the simultaneous determination of B12, its photoproduct aquocobalamin (B12a)/hydroxocobalamin (B12b), and AH2 at 550, 525 and 265 nm (pH 4.0). These wavelengths correspond to the absorption maxima of the three compounds and thus provide high specificity and sensitivity to the method. The method has been validated with respect to various analytical parameters. The recovery of the method for the three compounds ranges from 97.1-103.0% with a RSD value of ± 3%. The accuracy of the analytical method has been shown by the linearity of the kinetic plots in the concentration range studied. The method is simple, rapid and convenient for the purpose of assay and can also be used for the determination of B12 and B12b only at 550 and 525 nm in photolysed solutions. B12b only in the presence or absence of AH2 in photolysed solution can be determined at 525 nm. The photolysis of B12 and B12a/B12b in the presence of AH2 at pH 2.0-12.0, under aerobic conditions, follows first-order kinetics and the values of apparent first–order rate constants (kobs) at pH 2.0 to 12.0 range from 0.37–2.63×10–4 s–1 and 0.21–6.35×10–4 s–1, for B12 and B12a/B12b, respectively. The second–order rate constants (k2) for the photochemical interaction of AH2 and B12 and AH2 and B12a/B12b range from 0.20 (pH 2.0)–1.09 ×10–2 M–1s–1 (pH 5.0) and 5.88 (pH 2.0)–91.08 ×10–2 M–1s–1 (pH 5.0), respectively. The values of the k2 for AH2– B12a/B12b interaction are 30–80 times greater than those of AH2–B12 suggesting a greater susceptibility of B12a/B12b to photodegradation compared to that of B12 in this pH range. The k2–pH profiles for both B12 and B12a/B12b are bell–shaped curves indicating the effect of AH2 ionization on the rates of their interaction. The complete discoloration of B12 and B12a/B12b solutions on prolonged photolysis indicates the formation of corrin ring cleavage (oxidation) products in acid and alkaline solutions. These oxidation products do not absorb in the visible region and, therefore, do not interfere with the assay of B12 and B12a/B12b in the visible region. Reaction schemes for the mode of photodegradation of B12 and B12b in the presence of AH2 have been presented. The involvement of a short lived ligand-to-metal charge transfer (LMCT) intermediate state in the photolysis of B12 and the formation of different singlet states, on the photoexcitation of B12a/B12b, leading to the photodissociation of Co-OH bond by different mechanisms have been suggested. The photolysis of B12-cysteine and B12a/B12b-cysteine complexes has also been studied in the pH range 2.0-12.0 using a two-component spectrometric method by absorpbance measurements at 550 and 531 nm, the absorption maxima of B12-CY and B12b-CY complexes, respectively. The kinetics of these systems has been evaluated and the association constants for these complexes have been determined. The photolysis of B12 and B12b in the presence of ferrous ions has also been studied and the second-order rate constants for their photochemical interaction have been determined. The rates of interaction are affected by the pH of the medium as a result of the conversion of Fe2+ ions to Fe (OH)2 above pH 5.0.