SUITABILITY INDEX FOR COLLECTION BIN ALLOCATION USING ANALYTICAL HIERARCHY PROCESS (AHP) CASCADED TO ARTIFICIAL NEURAL NETWORK (ANN)

Municipal solid waste is an inevitable outcome of anthropogenic activities. Proper sustainable solid waste management is the need of the hour. In this study, a Suitability Index (S.I) has been determined which can measure the relative importance of a district with regard to its necessity or requirement of collection bins in comparison to other districts in a municipality. The S.I was computed using Analytical Hierarchy Process cascaded to Artificial Neural Network. Four criteria viz. Demographic, Social, Economic and Technical considerations and seven factors viz. Population Density (P.D), Street Width (S.W), Waste Generation Rate (W.G.R), Income Group Distribution (I.G.D), Average Minimum Distance between the bins (MIN.D), Available Number of Bins (A.N.B) and Cost of Waste Bins (C.W.B) were considered for developing the model. Available Number of Bins was found to have the highest impact on the model followed by C.W.B, W.G.R, MIN D., I.G.D, P.D, and S.W. This index will particularly help developing countries with resource constraint and unskilled labor force in Solid Waste Management. It will help such countries to easily locate districts in urgent need of collection bins with an easily available set of data and will help in increasing collection efficiency.</jats:p

Insights into the iron-ome and manganese-ome of Δmtm1 Saccharomyces cerevisiae mitochondria

Biophysical spectroscopies and LC-ICP-MS were used to evaluate the iron-ome and manganese-ome of mitochondria from Δmtm1 yeast cells. Deleting the mitochondrial carrier gene MTM1 causes Fe to accumulate in mitochondria and Mn superoxide dismutase (SOD2) activity to decline. One explanation for this is that some accumulated Fe misincorporates into apo-Sod2p. Mössbauer spectroscopy revealed that most of the accumulated Fe was Fe(III) nanoparticles which are unlikely to misincorporate into apo-Sod2p. Under anaerobic conditions, Fe did not accumulate yet SOD2 activity remained low, suggesting that the two phenomena are independent. Mn concentrations were two-fold higher in Δmtm1 mitochondria than in WT mitochondria. Soluble extracts from such samples were subjected to size-exclusion LC and fractions were analyzed with an on-line ICP-MS. Two major Mn peaks were observed, one due to MnSod2p and the other to a Mn species with a mass of 2–3 kDa (called Mn(2–3)). Mn(2–3) may deliver Mn into apo-Sod2p. Most Mn in WT mitochondria was associated with MnSod2p, whereas most Mn in Δmtm1 mitochondria was associated with Mn(2–3). The [Mn(2–3)] increased in cells grown on high MnCl(2) while the MnSod2p concentration remained unchanged. Corresponding Fe traces showed numerous peaks, including a complex of ~ 3 kDa which may be the form of Fe that misincorporates, and an Fe peak with the molecular mass of Sod2p that may correspond to FeSod2p. The intensity of this peak suggests that deleting MTM1 probably diminishes SOD2 activity by some means other than Fe misincorporation. A portion of Sod2p in Δmtm1 mitochondria might be unfolded or immature. Mtm1p may import a species required for apo-Sod2p maturation, activity or stability

Density Functional Theory Study of an All Ferrous 4Fe-4S Cluster

The all-ferrous, carbene-capped Fe4S4 cluster, synthesized by Deng and Holm (DH complex), has been studied with density functional theory (DFT). The geometry of the complex was optimized for several electronic configurations. The lowest energy was obtained for the broken-symmetry (BS) configuration derived from the ferromagnetic state by reversing the spin projection of one of the high spin (Si = 2) irons. The optimized geometry of the latter configuration contains one unique and three equivalent iron sites, which are both structurally and electronically clearly distinguishable. For example, a distinctive feature of the unique iron site is the diagonal Fe···S distance, which is 0.3 Å longer than for the equivalent irons. The calculated 57Fe hyperfine parameters show the same 1:3 pattern as observed in the Mössbauer spectra and are in good agreement with experiment. BS analysis of the exchange interactions in the optimized geometry for the 1:3, MS = 4, BS configuration confirms the prediction of an earlier study that the unique site is coupled to the three equivalent ones by strong antiferromagnetic exchange (J > 0 in J ∑j Ŝ4·Ŝj) and that the latter are mutually coupled by ferromagnetic exchange (J′ J′ ∑ij Ŝi·Ŝj). In combination, these exchange couplings stabilize an S = 4 ground state in which the composite spin of the three equivalent sites (S123 = 6) is antiparallel to the spin (S4 = 2) of the unique site. Thus, DFT analysis supports the idea that the unprecedented high value of the spin of the DH complex and, by analogy, of the all-ferrous cluster of the Fe-protein of nitrogenase, results from a remarkably strong dependence of the exchange interactions on cluster core geometry. The structure dependence of the exchange-coupling constants in the FeII-(μ3-S)2-FeII moieties of the all-ferrous clusters is compared with the magneto-structural correlations observed in the data for dinuclear copper complexes. Finally, we discuss two all-ferric clusters in the light of the results for the all-ferrous cluster

The Modular Nature of All-Ferrous Edge-Bridged Double Cubanes

Two all-ferrous, edge-bridged 8Fe−8S clusters, one capped with carbenes (2) the other with phosphenes (3), have been characterized by (57)Fe Mössbauer spectroscopy. The clusters have diamagnetic ground states that yield spectra consisting of one quadrupole doublet with a large splitting (25% of absorption) and one (3) or two (2) doublets with much smaller splittings (75% of absorption). These patterns closely resemble those observed for all-ferrous 4Fe−4S clusters. Structurally, the 4Fe−4S fragments of 2 and 3 are remarkably similar to all-ferrous 4Fe−4S clusters, sharing with them the characteristic 3:1 pattern of the iron sites, a differentiation that has been shown previously to reflect spontaneous distortions of the cluster core. These spectroscopic and geometric similarities suggest that the diamagnetic ground state of the 8Fe−8S cluster results from antiferromagnetic exchange coupling of two identical 4Fe−4S modules, each carrying spin S(4Fe) = 4. The iron atoms with the largest quadrupole splittings are located at the opposite ends of the body diagonal containing the bridging sulfides

The Lack of Synchronization between Iron Uptake and Cell Growth Leads to Iron Overload in <i>Saccharomyces cerevisiae</i> during Post-exponential Growth Modes

Fermenting cells growing exponentially on rich (YPAD) medium underwent a transition to a slow-growing state as glucose levels declined and their metabolism shifted to respiration. During exponential growth, Fe import and cell-growth rates were matched, affording an approximately invariant cellular Fe concentration. During the transition period, the high-affinity Fe import rate declined slower than the cell-growth rate declined, causing Fe to accumulate, initially as FeIII oxyhydroxide nanoparticles but eventually as mitochondrial and vacuolar Fe. Once the cells had reached slow-growth mode, Fe import and cell-growth rates were again matched, and the cellular Fe concentration was again approximately invariant. Fermenting cells grown on minimal medium (MM) grew more slowly during the exponential phase and underwent a transition to a true stationary state as glucose levels declined. The Fe concentration of MM cells that just entered the stationary state was similar to that of YPAD cells, but MM cells continued to accumulate Fe in the stationary state. Fe initially accumulated as nanoparticles and high-spin FeII species, but vacuolar FeIII also eventually accumulated. Surprisingly, Fe-packed 5-day-old MM cells suffered no more reactive oxygen species (ROS) damage than younger cells, suggesting that the Fe concentration alone does not accurately predict the extent of ROS damage. The mode and rate of growth at the time of harvesting dramatically affected cellular Fe content. A mathematical model of Fe metabolism in a growing cell was developed. The model included the import of Fe via a regulated high-affinity pathway and an unregulated low-affinity pathway. The import of Fe from the cytosol to vacuoles and mitochondria and nanoparticle formation were also included. The model captured essential trafficking behavior, demonstrating that cells regulate Fe import in accordance with their overall growth rate and that they misregulate Fe import when nanoparticles accumulate. The lack of regulation of Fe in yeast is perhaps unique compared to the tight regulation of other cellular metabolites. This phenomenon likely derives from the unique chemistry associated with Fe nanoparticle formation

Post-compilation optimization for multiple gains with pattern matching

Many existing retargetable compilers for ASIPs and domain-specific processors generate low quality code since the compiler is not able to fully utilize the intricacies of ISA of these processors. Hence, there is a need to further optimize the code produced by these compilers. In this paper, we introduce a new post-compilation optimization technique which is based on finding repeating instruction patterns in generated code and replacing them with their optimized equivalents. The instruction patterns to be found are represented by finite state machines which allow encapsulation of multiple patterns in just one representation, and instructions in a pattern to be not necessarily lexically adjacent. We also present a conflict resolution algorithm to select an optimization whenever a set of instructions fall under two or more different patterns of which only one can be applied on the basis of code size, cycle count or switching activity improvement. We tested this technique on the compiled binaries of ARM and Intel processors for code size improvement. We discuss the possible applications of this strategy in design space exploration (DSE) of embedded processors

The catalytic mechanism for aerobic formation of methane by bacteria. Nature 497, 132–136. doi: 10.1038/nature12061

Methane is a potent greenhouse gas that is produced in significant quantities by aerobic marine organisms 1 . These bacteria apparently catalyse the formation of methane through the cleavage of the highly unreactive carbon-phosphorus bond in methyl phosphonate (MPn), but the biological or terrestrial source of this compound is unclear 2 . However, the ocean-dwelling bacterium Nitrosopumilus maritimus catalyses the biosynthesis of MPn from 2-hydroxyethyl phosphonate 3 and the bacterial C-P lyase complex is known to convert MPn to methane Here we show that PhnJ is a novel radical S-adenosyl-L-methionine enzyme that catalyses C-P bond cleavage through the initial formation of a 59-deoxyadenosyl radical and two protein-based radicals localized at Gly 32 and Cys 272. During this transformation, the pro-R hydrogen from Gly 32 is transferred to the 59-deoxyadenosyl radical to form 59-deoxyadenosine and the pro-S hydrogen is transferred to the radical intermediate that ultimately generates methane. A comprehensive reaction mechanism is proposed for cleavage of the C-P bond by the C-P lyase complex that uses a covalent thiophosphate intermediate for methane and phosphate formation. The glutathione S-transferase (GST) fusion protein of PhnJ from Escherichia coli was purified under anaerobic conditions 8 . The isolated protein was dark brown in colour, had an absorbance maximum at a wavelength of 410 nm and was EPR silent (produced no electron paramagnetic resonance signal) It was shown previously that 59-deoxyadenosine (Ado-CH 3 ) and L-methionine are formed from the utilization of SAM during the reaction catalysed by PhnJ and that approximately one enzyme equivalent of SAM is consumed under single or multiple turnover