A review of methods to trace material flows into final products in dynamic material flow analysis: From industry shipments in physical units to monetary input–output tables,Part 1

Dynamic material flow analysis (dMFA) is widely used to model stock-flow dynamics. To appropriately represent material lifetimes, recycling potentials, and service provision, dMFA requires data about the allocation of economy-wide material consumption to different end-use products or sectors, that is, the different product stocks, in which material consumption accumulates. Previous estimates of this allocation only cover few years, countries, and product groups. Recently, several new methods for estimating end-use product allocation in dMFA were proposed, which so far lack systematic comparison. We review and systematize five methods for tracing material consumption into end-use products in inflow-driven dMFA and discuss their strengths and limitations. Widely used data on industry shipments in physical units have low spatio-temporal coverage, which limits their applicability across countries and years. Monetary input–output tables (MIOTs) are widely available and their economy-wide coverage makes them a valuable source to approximate material end-uses. We find four distinct MIOT-based methods: consumption-based, waste input–output MFA (WIO-MFA), Ghosh absorbing Markov chain, and partial Ghosh. We show that when applied to a given MIOT, the methods’ underlying input–output models yield the same results, with the exception of the partial Ghosh method, which involves simplifications. For practical applications, the MIOT system boundary must be aligned to those of dMFA, which involves the removal of service flows, sector (dis)aggregation, and re-defining specific intermediate outputs as final demand. Theoretically, WIO-MFA, applied to a modified MIOT, produces the most accurate results as it excludes massless and waste transactions. In part 2 of this work, we compare methods empirically and suggest improvements for aligning MIOT-dMFA system boundaries.     

Chloroplast DNA variation and phylogeny of theRanunculaceae

Restriction site mapping of chloroplast DNA from 31 species representing 26 genera of theRanunculaceae was performed using eleven restriction endonucleases. The chloroplast genome varies in length from approximately 152 to 160 kb. Length variants are frequent in theRanunculaceae and range from usually less than 300 bp to rarely 1.5 kb. The inverted repeat is extended into the large single copy (LSC) region by 4–4.5 kb inAnemone, Clematis, Clematopsis, Hepatica, Knowltonia, andPulsatilla. Several inversions are present in the LSC-region of the cpDNA in all these genera and inAdonis. The frequency of restriction site mutations varies within the chloroplast genome in theRanunculaceae between 4 and 32 mutations per kilobase, and is lowest in the inverted repeat and the regions containing the ATPase-genes and the genespsaA, psaB, psbA, rpoB, andrbcL. A total of 547 phylogenetically informative restriction sites was utilized in cladistic analyses of the family using Wagner, Dollo, and weighted parsimony. These three parsimony analyses result in different tree topologies. Four, six, and one equally most parsimonious trees were obtained with Wagner, Dollo, and weighted parsimony, respectively. The amount of support for the monophyletic groups was evaluated using bootstrapping and decay analysis. All three parsimony methods suggest thatHydrastis is the sister group to the remainder of theRanunculaceae, and that theAnemone-Clematis group, which shares several derived cpDNA rearrangements, is monophyletic. Only a few of the traditional groups in theRanunculaceae are supported by cpDNA restriction side data. Only Dollo parsimony provides support for the hypothesis thatThalictroideae andRanunculoideae are monophyletic.     

Environmentally friendly protocol for the determination of sitagliptin phosphate in pharmaceutical preparations and biological fluids using l-tyrosine as a fluorescence probe

A responsive spectrofluorometric method was developed for the determination of sitagliptin phosphate using l -tyrosine as a fluorescence probe. The fluorescence intensity of l -tyrosine was quenched with sitagliptin phosphate. The fluorescence intensity was recorded at 307 nm using a 272 nm excitation wavelength. The calibration plot between fluorescence intensity and the concentration of drug was linear in the range of 0.1 to 2.0 mM with a good correlation value of 0.997. The limit of detection and quantification were established to be 3.7 × 10⁻⁴ and 1.23 × 10⁻³ mM, respectively. Commonly used excipients did not interfere with sitagliptin phosphate measurement. The proposed method was used to measure the sitagliptin phosphate in its standard type, dosage form, and biological samples. The percent recovery ranged from 97.41–103.36%. The static quenching was shown to be responsible for quenching as indicated by the Stern–Volmer plot. The method was validated using ICH guidelines and profitably applied for the content uniformity test, resulting in a high percent recovery and small relative standard deviation. The proposed approach is effortless, susceptible, selective, economic, and provides a high precision and accuracy, and can be used to determine sitagliptin phosphate in the pharmaceutical industry.     

Xcp-mediated protein secretion in Pseudomonas aeruginosa: identification of two additional genes and evidence for regulation of xcp gene expression

In Pseudomonas aeruginosa, several exoproteins synthesized with a signal sequence (elastase, lipase, phospholipases, alkaline phosphatase and exotoxin A) are secreted by a two-step mechanism. They first cross the inner membrane in a signal sequence-dependent way, and are further translocated across the outer membrane in a second step requiring secretion functions encoded by several xcp genes. Ten xcp genes have already been characterized (Bally et al., 1992a). In this study, two additional xcp genes, xcpP and xcpQ, are described. They are located in the 40 min region of the chromosome where they probably define an operon, divergent from the xcpR–Z operon previously characterized in this region. These two genes encode two proteins, XcpP and XcpQ, similar to PulC and PulD of the pul system of Klebsiella oxytoca. Moreover, the two divergent operons share a common regulation which is growth-phase dependent.     

Composite origin of major histocompatibility complex genes

Major histocompatibility complex WHO genes have now been cloned from representatives of all vertebrate classes except Agnatha. The recent accumulation of sequence data has given great insight into the course of evolution of these genes. Although the primary structure of the MHC genes varies greatly from class to class and also within the individual classes, the general features of the tertiary and quaternary structure have been conserved remarkably well during more than 400 million years.of evolution. The ancestral MHC genes may have been assembled from at least three structural elements derived from different gene families. Class II MHC genes appear to have been assembled first, and then to have given rise to class I genes.