Radiation, optical, power flow, and electrical diagnostics at the Z facility: Layout and techniques utilized to operate in the harsh environment.

The Z machine is a current driver producing up to 30 MA in 100 ns that utilizes a wide range of diagnostics to assess accelerator performance and target behavior conduct experiments that use the Z target as a source of radiation or high pressures. We review the existing suite of diagnostic systems, including their locations and primary configurations. The diagnostics are grouped in the following categories: pulsed power diagnostics, x-ray power and energy, x-ray spectroscopy, x-ray imaging (including backlighting, power flow, and velocimetry), and nuclear detectors (including neutron activation). We will also briefly summarize the primary imaging detectors we use at Z: image plates, x-ray and visible film, microchannel plates, and the ultrafast x-ray imager. The Z shot produces a harsh environment that interferes with diagnostic operation and data retrieval. We term these detrimental processes "threats" of which only partial quantifications and precise sources are known. We summarize the threats and describe techniques utilized in many of the systems to reduce noise and backgrounds.

Technique for fabrication of ultrathin foils in cylindrical geometry for liner-plasma implosion experiments with sub-megaampere currents.

In this work, we describe a technique for fabricating ultrathin foils in cylindrical geometry for liner-plasma implosion experiments using sub-MA currents. Liners are formed by wrapping a 400 nm, rectangular strip of aluminum foil around a dumbbell-shaped support structure with a non-conducting center rod, so that the liner dimensions are 1 cm in height, 6.55 mm in diameter, and 400 nm in thickness. The liner-plasmas are imploded by discharging ∼600 kA with ∼200 ns rise time using a 1 MA linear transformer driver, and the resulting implosions are imaged four times per shot using laser-shadowgraphy at 532 nm. This technique enables the study of plasma implosion physics, including the magneto Rayleigh-Taylor, sausage, and kink instabilities on initially solid, imploding metallic liners with university-scale pulsed power machines.

Scanning mutagenesis of Mcm1: residues required for DNA binding, DNA bending, and transcriptional activation by a MADS-box protein.

MCM1 is an essential gene in the yeast Saccharomyces cerevisiae and is a member of the MADS-box family of transcriptional regulatory factors. To understand the nature of the protein-DNA interactions of this class of proteins, we have made a series of alanine substitutions in the DNA-binding domain of Mcm1 and examined the effects of these mutations in vivo and in vitro. Our results indicate which residues of Mcm1 are important for viability, transcriptional activation, and DNA binding and bending. Substitution of residues in Mcm1 which are highly conserved among the MADS-box proteins are lethal to the cell and abolish DNA binding in vitro. These positions have almost identical interactions with DNA in both the serum response factor-DNA and alpha2-Mcm1-DNA crystal structures, suggesting that these residues make up a conserved core of protein-DNA interactions responsible for docking MADS-box proteins to DNA. Substitution of residues which are not as well conserved among members of the MADS-box family play important roles in contributing to the specificity of DNA binding. These results suggest a general model of how MADS-box proteins recognize and bind DNA. We also provide evidence that the N-terminal extension of Mcm1 may have considerable conformational freedom, possibly to allow binding to different DNA sites. Finally, we have identified two mutants at positions which are critical for Mcm1-mediated DNA bending that have a slow-growth phenotype. This finding is consistent with our earlier results, indicating that DNA bending may have a role in Mcm1 function in the cell.

Microheterogeneity of type II cAMP-dependent protein kinase in various mammalian species and tissues.

Excluding autophosphorylated species, at least six forms of the regulatory subunit of type II cAMP-dependent protein kinase (RII) from various mammalian tissues were identified by sodium dodecyl sulfate (SDS) gel electrophoresis of purified samples and of crude preparations photoaffinity labeled with 8-azido[32P] cAMP and by gel filtration. After autophosphorylation some heart RII forms termed type IIA (bovine, porcine, equine, and dog) shifted to a more slowly migrating band on SDS gels while others termed type IIB (rat, guinea pig, rabbit, and monkey) did not detectably shift. Both subclasses of RII exhibited variation in apparent Mr on SDS gels. Bovine and porcine heart nonautophosphorylated RII had Mr 56,000 and the autophosphorylated RII had Mr 58,000, while dog and equine heart RII had Mr 54,000 and 56,000 while rabbit and guinea pig heart RII had Mr 52,000. More than one RII was found in different tissues of the same species. Rabbit skeletal muscle contained a Mr 56,000 IIB form. Bovine lung contained almost equal amounts of a IIA form apparently identical to that of bovine heart and a Mr 52,000 IIB form similar to that which predominated in bovine brain. Rat adipose tissue, brain, and monkey heart contained predominantly a Mr 51,000 IIB form. The rat liver Mr 56,000 IIB form chromatographed differently from all other RII tested by gel filtration. Several lines of evidence indicated that the various forms of RII were not derived from one another through proteolysis or other processes. Each of the type II forms rapidly incorporated 0.3-1.0 mol of 32P per mol of subunit when incubated with [gamma-32P]ATP and C subunit. Four of the forms tested were similar in the cAMP concentration dependence for activation of their corresponding holoenzymes and inhibited C subunit about equally. Each exhibited two components of [3H]cAMP dissociation, indicating two intrachain cAMP-binding sites, and the dissociation rates for the respective sites were similar.

Effect of cyclic nucleotide analogs on intrachain site I of protein kinase isozymes.

The effects of numerous cAMP analogs present in the [3H]cAMP binding reaction on subsequent dissociation of [3H]cAMP from the regulatory subunit of cAMP-dependent protein kinase I and II were analyzed. Certain analogs with modification at either C-8 or C-2 showed relative selectivity for one (site 1) of two intrachain cAMP binding sites of both isozymes. Modification at C-6 caused selectivity for the second site (site 2). The combination of a site-1-directed and site-2-directed analog inhibited [3H]cAMP binding much more than did either analog alone. In general, there was a correlation between the site 1 selectivity and the ability of the analog to stimulate the binding of [3H]cIMP, which selects site 2. The site-1-directed analogs stimulated the initial rate of [3H]cIMP binding. The stimulatory effect was enhanced in the presence of a polycationic protein such as histone and was inhibited by high ionic strength. The type I and II isozymes exhibited large differences in analog specificity for this effect. For type I, of the analogs tested the most efficacious for stimulating [3H]cIMP binding were those containing a nitrogen atom attached to C-8, 8-aminobutylamino-cAMP being the most effective. Type II responded best to analogs containing a sulfur atom attached to C-8, 8-SH-cAMP being the most effective of those tested. The stimulatory effect was accentuated in the presence of MgATP when using type I, but this nucleotide had no effect when using type II. It is proposed that in intact tissues cAMP binding to site 1 of either isozyme stimulates the binding to site 2.

[Accuracy of clinical findings in patients with disturbed myocardial function in acute myocardial infarction]. / Treffsicherheit der klinischen Beurteilung von Patienten mit eingeschränkter myokardialer Funktion bei akutem Myokardinfarkt.

The relationship between clinical findings and invasively measured hemodynamic data was investigated in a prospective trial of 70 patients with acute myocardial infarction. In 26 out of 27 consecutive patients without clinical signs of disturbed myocardial function, normal hemodynamic values were also found invasively. In 43 patients, depressed myocardial function was diagnosed on the basis of the clinical findings. These findings were verified in 38 patients (88%) by means of cardiac catheterization; 5 patients (12%) had normal hemodynamic values. In 26 patients with clinical signs of congestive heart failure, an attempt was made to identify non-invasively those with a low output (cardiac index less than 2/min/m2). Only 3 of the 6 patients with a low output could be identified by clinical examination alone. In one patient a low output was clinically diagnosed despite normal cardiac function measured invasively. In 16 patients, 48 subsequent clinical examinations were performed during treatment of congestive heart failure to identify either persistent elevated left ventricular filling pressure or low output; 15 (31%) were found to be incorrect when compared with the cardiac catheterization data. Patients with acute myocardial infarction and normal ventricular function can be identified with high accuracy by means of clinical examination alone. The clinical diagnosis of congestive heart failure was incorrect in 12% of the patients. A low output state in acute myocardial infarction is often overlooked in clinical examination alone. Of the clinical examinations on patients during therapy, 30% were incorrect. Invasive hemodynamic monitoring in acute myocardial infarction therefore appears to be unnecessary in patients with normal clinical findings, but in those with clinically diagnosed congestive heart failure it is mandatory for precise indication and evaluation of therapy.

[Cell-wall composition during inhibition of hypocotyl elongation in the mustard seedling (sinapis alba L.) by inhibitors or phytochrome]. / Die Zellwandzusammensetzung von Hypokotylen des Senfkeimlings (Sinapis alba L.) bei Wachstumshemmung durch Inhibitoren oder Phytochrom.

During inhibition of hypocotyl elongation in the mustard seedling by actinomycin D, hydroxyproline, and continuous far-red via phytochrome 730 the synthesis of cell-wall carbohydrates is impaired in the same manner. Independent of the treatment 12 hrs after its beginning at a relative inhibition of hypocotyl elongation of 80-90% the relative inhibition of the cell-wall carbohydrate content is uniformly about 30-35%. No significant quantitative nor apparent qualitative differences in the sugar and uronic acid content of the pectic, hemicellulosic, and α-cellulosic cell-wall fraction could be detected.

Dose response behaviour for polarotropism of the germ tube of the liverwort Sphaerocarpos Donnellii aust.

The dose response behaviour for polarotropism of the unicellular germ tube of Sphaerocarpos was studied in blue and near UV. At constant intensities the response is proportional to the logarithm of the exposure duration, and at constant exposure durations the response is proportional to the logarithm of intensity. Neither a polarotropic response to wavelengths > 550 nm, nor a significant influence on response to blue of a pre-, post-, or simultaneous-irradiation with red or far-red could be observed. Also a dark period was without any effect on the polarotropic response to blue. Growth responses under linearly polarized light are described.

Action spectrum for polarotropism of the germ tube of the liverwort Sphaerocarpos Donnellii aust.

A series of dose response curves was worked out in the polarotropically active blue and UV spectral region. These dose response curves show changes in slope as a function of wavelength. In blue the slope values are higher than in UV. As a consequence, both the relative height of the peaks in blue and UV and the fine characteristics in blue of the action spectrum calculated on the basis of these dose response curves change decisively with different response levels taken for calculation. Therefore no decision can be made as to what photoreceptor(s) might be involved. Though at medium response levels the action spectra show similarity with action spectra of other blue-UV-mediated photoresponses, which generally are believed as being indicative of some flavin.

[Short term changes in soluble sugar and cell-wall carbohydrate content during phytochrome mediated photomorphogenesis in the mustard seedling (Sinapis alba L.)]. / Rasch ablaufende Änderungen im Gehalt an löslichen Zuckern und Zellwandkohlenhydraten bei der phytochrominduzierten Photomorphogenese des Senfkeimlings (Sinapis alba L.).

Short term changes in the soluble sugar, starch, and cell-wall carbohydrate content of the mustard seedling have been studied in the different organs during phytochrome induced photomorphogenesis in continuous far-red. The program was: imbibition of seeds →36 hrs dark → far-red irradiation. Kinetics have been followed up to 12 hrs after the onset of irradiation.There are no substantial changes in carbohydrate content in the cotyledons and the radicle. In the cotyledons in far-red after a lag-phase of 3 hrs, there is a decrease in oligosaccharide content, and after a lag-phase of 6 hrs, an increase in cell-wall synthesis. The reducing sugar and starch content is not altered upon irradiation. In the radicle immediately after the onset of far-red, there is a temporary rise in the reducing sugar and cell-wall carbohydrate content. However, 6 hrs later the values in far-red again parallel those of the dark control.The important phytochrome dependent changes take place in the hypocotyl. In far-red after a lag-phase of 3 hrs the glucose accumulation is markedly retarded, the sucrose and starch content no longer increased, and the fructose content even decreases below the 3 hrs value. The glucose: fructose ratio, which is constant in dark, is shifted in favour of glucose. The lag-phase of phytochrome controlled hypocotyl elongation is about 1 hr, the lag-phase of the inhibition of cell-wall carbohydrate synthesis is in about the same order of magnitude.There seems to be neither any immediate connection between sugar content and cell-wall carbohydrate synthesis, as shown by the difference in lag-phases, nor does there seem to be any direct relationship between hypocotyl inhibition and overall synthesis of cell-wall material. The relative inhibition of cell-wall synthesis is less than one third of that of hypocotyl elongation (Figs. 5,6). Apparently phytochrome controls hypocotyl elongation by influencing the cell-wall structure.In spite of the fact that fat degradation is higher in far-red than in dark and respiration higher in dark than in far-red (FRIEDERICH, 1968), 6 hrs after the onset of far-red the increase of total carbohydrate content declines compared with that in dark. This finding leads to the conclusion that the efficiency of the fat-carbohydrate-transformation is higher in dark than in far-red.