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Notes: Any scheme for developing our water resources must eventually focus on the hydrologic theme for answers to pressing questions about anticipated availability of water. These answers will only be as realistic as the data is reliable, inferring accuracy as well as sufficiency. To that effect, more hydrologic and meteorologic data collection stations must be added to the existing network throughout the country, and the basic instrumentation presently in use should be made more versatile, but without an accompanying near-astronomical increase in cost and in complexity. The ubiquitous so-called current meters are a case in point.Current meters have almost certainly received more man-hours of use in the field of Water Resources than any other instrument ever devised to measure stream velocity. In spite of more esoteric equipment appearing on the specialized market each year, the time-honored method of stream gaging by the velocity-area method is still widely practiced, and the basic instrument remains the current meter. The same persistent use is essentially true for the anemometer, or “wind current meter.” Over the past 30 years, a great many studies have been made to define operational parameters, particularly with respect to the statistics of data reliability. Today's needs are different from those acceptable a few years back, yet in many instances yesterday's instrument can be metamorphosed to satisfy present practice.Besides a discussion of some of the fundamental problems of data collection which must be accounted for in all areas of water resources where water and air currents must be known in space and in time, the authors present a brief critique of several new hybrid types of current meters. Two of these meters were designed especially to fill the gap between sophisticated and specialized equipment of high cost, and relatively inexpensive simpler devices lacking however the advantages of automation and self-recording features.Since the mechanical performance of current meters has been the subject of many past studies fully reported in various professional journals, it appeared advantageous to develop electronic refinements on such a type of widely used instrument. A period of research, first at Washington State University and presently at Clarkson College of Technology, produced two electronic packages applicable to current meters. The rationale of these studies was to increase the usefulness of current meters by providing velocity readout, either instantaneous or time-averaged; to include data recording on tape if and when such would be desired, together with the necessary playback facility; and to keep the electronic system independent of the current meter size.The paper describes in some detail the photo-electronic tachometer which seems to offer more reliability and flexibility of operation than induction-type transducers. One of the features most worthy of consideration is the adaptability of such device to any size of current meter frame and vanes. The rotation of an impeller one-half inch in diameter is recorded by the instrument as faithfully as that of one six inches in diameter. Where velocity transients are to be observed, the advantages of a greatly reduced inertia are evident. The inherent ruggedness of low current drain transistors and integrated circuits should make this light-actuated meter readout device well-suited for remote applications.

Notes: A new family of homologous membrane proteins that transport galactosides–pentoses–hexuronides (GPH) is described. By analysing the aligned amino acid sequences of the GPH family, and by exploiting their different specificities for cations and sugars, we have designed mutations that yield novel insights into the nature of ligand binding sites in membrane proteins. Mutants have been isolated/constructed in the melibiose transport proteins of Escherichia coliKlebsiella pneumoniae and Salmonella typhimurium, and the lactose transport protein of Streptococcus thermophilus which facilitate uncoupled transport or have an altered cation and/or substrate specificity. Most of the mutations map in the amino-terminal region, in or near amphipathic α-helices II and IV, or in interhelix-loop 10–11 of the transport proteins. On the basis of the kinetic properties of these mutants, and the primary and secondary structure analyses presented here, we speculate on the cation binding pocket of this family of transporters. The regulation of the transporters through interaction with, or phosphorylation by, components of the phosphoenolpyruvate:sugar phosphotransferase system is also discussed.

Notes: [Auszug] The observation that a few species in ecological communities are exceptionally abundant, whereas most are rare, prompted the development of species abundance models. Nevertheless, despite the large literature on the commonness and rarity of species inspired by these pioneering studies, some ...

Notes: The effect of a localized SiO2 codoping on the conversion of polycrystalline, MgO-doped Al2O3 tubes to single-crystal sapphire was investigated. Codoping with SiO2 before sintering intentionally triggered abnormal grain growth, which resulted in the full conversion of tube surfaces to single crystal without adversely affecting densification to a almost pore-free, translucent state. The degree of surface conversion was strongly dependent on experimental variables, which included furnace temperature and codoping amount. Surface-converted tubes had excellent physical properties, which included good thermal cycling resistance and optical properties superior to unconverted, polycrystalline Al2O3.

Notes: l-Fucose (6-deoxy-l-galactose) is used as sole carbon source by many microorganisms, and its transport into Escherichia coli is mediated by An l-fucose-H+ symport activity, in order to determine the nature of a putative transporter encoded by the E. coli fucP gene and Identify its protein product it was cloned downstream of the inducible T7 RNA polymerase and lambda Ol Pl promoters, induction of the T7 promoter resulted in the expression of [14C]-l-fucose uptake activity and the concomitant expression of a [35S]-Met-labelled 32 kDa protein at levels too tow for detection by staining with Coomassie briiiiant blue or for protein sequencing, induction of the lambda Ol Pl promoter caused the appearance of l-fucose-H+ symport activity and of a Coomassie brilliant blue-stained 32 kDa membrane protein expressed at high levels sufficient for identification as FucP by N-terminal protein sequencing. The FucP protein is, therefore, a sugar-H+ symporter different in amino acid sequence from any other known transporter. These and other results illustrate the general unpredictability of cloning strategies for attempting the amplified expression of membrane transport proteins.

Notes: The transport of l-fucose into Escherichia coli is mediated by the l-fucose-H+ symport protein (FucP). The fucP gene has been sequenced and encodes a hydrophobic protein that contains 438 amino acid residues, with a predicted Mr of 47773. The hydropathic profile of FucP indicates 10 to 12 hydrophobic regions that could span the membrane as α-helices. A 12-helix model with the N- and C-termini located in the cytoplasm was derived from the hydropathic profile and from application of the ‘positive inside’ rule. This model was tested using β-lactamase fusion technology. Analyses of 62 different FucP-β-lactamase fusions suggested that the FucP protein crosses the cytoplasmic membrane of E. coli 12 times, with the N- and C-termini in the cytoplasm. From measurements of [14C]-l-fucose uptake, it was deduced that the last putative transmembrane region must be complete for transport activity to be retained and that the four C-terminal residues were unnecessary for transport activity. Fourier transform analyses show that all the predicted helices contain a periodicity that enables hydrophobic/hydrophilic faces to be identified; these were particularly evident in putative helices 1, 3, 4, 5, 6, 10 and 11.

Notes: REVIEW ESSAYS

Notes: Abstract Exposure to diatomaceous earth with low crystalline silica content (〈 1%) is rarely reported to cause pneumoconiotic disease, whereas airway obstruction and bronchitis are more frequently reported. We investigated the occurrence of pneumoconiosis and airflow limitation in 172 male workers from 5 potato sorting plants (55 controls, 29 salesmen, 72 currently exposed, and 16 retired exposed) exposed to inorganic dust from former sea terraces (7.7–15.4 mg/m3), high in diatomaceous earth. The presence of fibrosis was evaluated by chest radiographs (exposed only) and serum levels of type III procollagen (P-III-P) were measured as an estimate of fibrogenetic activity. Lung function was assessed by flow volume curves and impedance measurements. A validated questionnaire was used to record respiratory symptoms. No pneumoconiotic abnormalities were demonstrated by chest radiographs. In line with this finding, serum P-III-P levels were not elevated in exposed workers as compared to controls, suggesting no differences in fibrogenetic activity. In fact, serum P-III-P levels decreased significantly (P 〈 0.03) with increasing cumulative exposure. Flow volume parameters indicated airflow obstruction, dose-related to (cumulative) dust exposure; the annual decline in forced expiratory flow volume (FEV1) was estimated at 10.5 m1/year (P 〈 0.05). Airway obstruction was confirmed by impedance analysis: In the retired group impedance changes were compatible with airway obstruction extending into the peripheral airways. We conclude that this exposure to quartz during potato sorting does not result in an increased risk for pneumoconiosis, but that (prolonged) surveillance in this group is desirable in order to detect early indications of airflow obstruction.