scholarly journals Determination of cooperative interaction between clusters in Clostridium pasteurianum 2 (4Fe-4S) ferredoxin.

1979 ◽  
Vol 254 (11) ◽  
pp. 4499-4501
Author(s):  
W.V. Sweeney ◽  
B.A. McIntosh
Robotica ◽  
1985 ◽  
Vol 3 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Ernest W. Kent ◽  
Thomas Wheatley ◽  
Marilyn Nashman

SUMMARYWhen applied to rapidly moving objects with complex trajectories, the information-rate limitation imposed by video-camera frame rates impairs the effectiveness of structured-light techniques in real-time robot servoing. To improve the performance of such systems, the use of fast infra-red proximity detectors to augment visual guidance in the final phase of target acquisition was explored. It was found that this approach was limited by the necessity of employing a different range/intensity calibration curve for the proximity detectors for every object and for every angle of approach to complex objects. Consideration of the physics of the detector process suggested that a single log-linear parametric family could describe all such calibration curves, and this was confirmed by experiment. From this result, a technique was devised for cooperative interaction between modalities, in which the vision sense provided on-the-fly determination of calibration parameters for the proximity detectors, for every approach to a target, before passing control of the system to the other modality. This technique provided a three hundred percent increase in useful manipulator velocity, and improved performance during the transition of control from one modality to the other.


1999 ◽  
Vol 32 (6) ◽  
pp. 1180-1182 ◽  
Author(s):  
John W. Peters ◽  
Henry D. Bellamy

The structure of the hydrogenase (CpI) fromClostridium pasteurianumhas been solved by MAD phasing taking advantage of the presence of 20 Fe atoms in the native ~60 kD protein. The Fe atoms in this protein are distributed into five [FeS] clusters that could easily be identified in Patterson maps. Although the individual sites for the Fe atoms within the [FeS] cluster could not be identified directly, phasing to the maximum resolution (2.5 Å) of the MAD data was achieved by an iterative assignment and refinement of the positions of individual Fe atoms based mainly on the known structure of several of the metal clusters. After the majority of the Fe atoms had been successfully assigned and refined in this manner, excellent quality electron-density maps were obtained which allowed the amino acid chain to be traced.


Development ◽  
1983 ◽  
Vol 76 (1) ◽  
pp. 115-137
Author(s):  
Hans Meinhardt

We postulate that positional information for secondary embryonic fields is generated by a cooperative interaction between two pairs of differently determined cell types. Positional information is thus generated at the boundaries between cells of different determination. The latter are assumed to result from the primary pattern formation in the embryo. The application of this model to vertebrate limbs accounts for the pairwise determination of limbs at a particular location, with a particular handedness and alignment to the main body axes of the embryo. It accounts further for the gross difference in the regeneration of double anterior and double posterior amphibian limbs as well as for the formation of supernumerary limbs after certain graft experiments including supernumeraries in which the dorsoventral polarity changes or which consist of two anterior or two posterior halves. Our model provides a feasible molecular basis for the polar coordinate model and successfully handles recently found violations, for instance formation of supernumerary limbs after ipsilateral grafting with 90° rotation. The most frequent types of developmental malformations become explicable. The models allow specific predictions which are fully supported by recent experiments (see the accompanying paper of M. Maden).


2021 ◽  
Vol 11 (5) ◽  
pp. 207-212
Author(s):  
V. Polyovyy ◽  
I. Dzyubanovsky ◽  
A. Kovalchuk ◽  
O. Dzyubanovsky ◽  
V. Dzhyvak

Acute pancreatitis is one of the most pressing problems of modern pancreatology, according to the authors ranks first among surgical pathologies.The aim of this study was to evaluate the dynamics of cytokine profile in patients with abdominal sepsis caused by pancreatic necrosis.Materials and methods.The study was conducted in 12 patients diagnosed with abdominal sepsis caused by pancreatic necrosis, in the period from 2017 to 2020 who were treated in medical hospitals in Chernivtsi and Ternopil. The control group consisted of 17 patients without signs of abdominal sepsis and acute surgical pathology. Both groups were representative by age, sex, comorbidities, risk factors. Determination of experimental parameters in the blood of patients was performed in the postoperative period (the results were evaluated before surgery, on the first and tenth days of the postoperative period).Research results and their discussion.In patients with abdominal sepsis, a violation of the mechanisms of cell adhesion and costimulatory-cooperative interaction of immunocompetent cells was observed in the preoperative period, as indicated by the low level of CD11a + and CD162 + expression on them. The decrease in the content of IL-6 in the blood with a slight progressive increase in the level of IL-4 corresponds to a moderate imbalance of cytokine regulation of the immune response.


1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.


1999 ◽  
Vol 190 ◽  
pp. 549-554
Author(s):  
Nino Panagia

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.


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