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More than a century after Mark Twain argued that the Mississippi River could never be tamed by engineers, dams and dikes constrain the great waterway. Its once muddy waters run [...]

Cryopreservation is the long-term, indefinite storage of living biological resources at ultralow temperatures. It is almost universally assumed that cryogenic storage supports genetic and phenotypic stability of organisms. However, certain components of the cryopreservation process, particularly some cryoprotective additives (CPAs) and free radical mediated cryoinjury, may potentially cause genetic alterations. Genetic integrity in cryopreserved microalgae was assessed using a very sensitive molecular fingerprinting technique, AFLP, on 28 terrestrial microalgal strains. In about half of all investigated strains the AFLP fingerprints revealed, with high levels of reproducibility, clearly detectable genomic differences after cryopreservation employing a widely used standard two-step cooling protocol. Differences ranged from a single fragment position to multiple fragment changes and were compared to differences found between wild-type and UV-light- or radioisotope-induced mutants of Parachlorella kessleri. The basis of the changes are discussed in terms of their reversibility, as may be the case if they are attributed to DNA methylation and/or whether they are true mutations that may potentially manifest in the phenotype. The possibility that cryopreservation selects for genotypically different subpopulations of microalgae is also considered. Key words: AFLP; algae; cryopreservation; culture collections; DNA methylation; genetic stability.

Abstract This article argues that popular culture such as music, movies, and television should be used as additional 'text' in the language arts classroom to build stronger connections with traditional [...]

A study is conducted to determine the effect on tuberculosis incidence of a clinic providing isoniazid preventive therapy to human immunodeficiency virus (HIV)-infected adults under routine conditions. The findings indicate that tuberculosis incidence remained high despite isoniazid preventive therapy and additional interventions are suggested in order to effectively reduce morbidity and mortality in HIV-infected patients.

Insect repellents that contain DEET are more effective than other repellents. In a study of 16 different repellents, DEET repellents protected people for up to five hours whereas the non-DEET repellents protected people for 20 minutes or less.

This article offers a quantitative method to help small- to medium-sized enterprises more effectively manage their operations. Topics addressed include the business life cycle, marketing management, and interpreting performance data.

The small firm is likely to dominate as a business form in the economy. In 1998 it provided most new jobs, a third of high tech occupations and 55% in innovative jobs. Hence, marketing management, innovation and creativity should be encouraged in small firms.

The structure of the subtilisin protease from Penicillium cyclopium was described through crystallization with p-phenylmethanesulfonyl fluoride (PMSF). X-ray diffraction analysis revealed that the structural profile of P. cyclopium was almost similar to that of proteinase K of Tritirachium album except for the absence of disulfide bond in P. cylopsium and the orientation of the histidine in the catalytic site. Furthermore, it was indicated that the presence of cysteine in the active site and the presence of calcium in the binding site has no effect on the catalytic activity.

Natural wetlands are a cheap alternative to traditional wastewater treatment and can be maintained at higher quality levels and are more economically viable than traditional technologies or the creation of new wetlands. The natural wetland system can be improved by discharging nutrients and sediment rich wastewater. The saving is around $785-1500 per acre over existing technology.

Molecular replacement using real space Patterson search and filtering by Patterson correlation-coefficient treatment provided the crystal structures of the complex between anti-idiotypic Fab 409.5.3 and idiotypic Fab fragment of virus-neutralize antibody. Nine probable hydrogen bonds and elaborate, specific interactions involving 118 van der Waals contacts are evident for the three-dimensional structure.

Synthetic aperture radar (SAR) data were acquired over Bonanza Creek Experimental Forest (Alaska) in March 1988 under thawed and frozen conditions. For five stands analyzed, L-band backscatter at 42 degrees-45 degrees incidence angle was 2.7-6.9 dB smaller under frozen than under thawed conditions for white spruce and balsam poplar, with the largest difference at HV and the smallest at HH polarization. The differences were smaller for a stand of small black spruce. The VV-HH phase differences observed by SAR were approximately equal to 0 degree for all the stands. Ground data were used to parameterize the Santa Barbara canopy backscatter model. For the white spruce and balsam poplar stands under thawed conditions, simulations agreed with the SAR data within the calibration uncertainty. The model underestimated the HH, HV, and VV backscatter for all five stands under frozen conditions, and for the black spruce stand under thawed conditions. The modeled VV-HH phase differences were close to 0 degree for all the stands except the black spruce stand. The discrepancies in model predictions of backscatter and phase difference were attributed to inadequate surface backscatter modeling. Model results supported the hypothesis that the weaker backscatter from frozen, as compared with thawed stands, was because of the smaller dielectric constant of the frozen trees.

X-ray crystallographic analysis has determined the form of the satellite tobacco mosaic virus (STMV) at 3.5 angstroms. STMV's amino-acids 37-159 are arrayed as an eight-stranded anti-parallel beta-barrel with a Swiss roll shape resembling what has been observed in the coat proteins of other viruses. Moreover, most of STMV's quaternary interactions are caused by a 60-angstrom-long amino-terminal strand. STMV's double-stranded RNA makes up 44% of the genome, the highest percentage found in any virus so far.

The organization of IgG2a, an antitumor monoclonal antibody that attacks canine lymphoma, has been determined at the 3.5 angstrom level. Canine lymphoma is similar to human non-Hodgkin's lymphoma. The antibody's internal arrangement includes an asymmetric conformation, two separately functioning dyads and a two-fold axis pertaining to the Fc part of the molecule. The intricate and adaptable structuring of this antibody has demonstrated anew the immune system's capacity to respond to tumors.

The noun leadership is traditionally defined as 'to cause to follow.' If a high school teacher had asked the class to write a short paper on 'The Leadership of George [...]

X-ray crystallographic analyses of pig pancreatic [alpha]-amylase which contain a limit dextrin of six glucose residues, oligosaccharide, and [alpha]-cyclodextrin is reported. A comprehensive integration of the complexes provides a pathway to construct a model for the binding of polysaccharides which have the helical character found in natural substrates such as starch and glycogen.

A study is conducted on classifications of enterpreneurship theories and enterpreneurial capacity of small to medium-sized enterprises.

The authors have investigated xylanase from the bacterial plant pathogen Erwinia chrysanthemi expressed in Escherichia coli. They report that the room-temperature structure of this xylanase has been determined via multiple isomorphous replacement.