Quantitative Studies in Early Ovule and Fruit Development: Developmental Constraints in Balsamorhiza sagittata and B. hookeri

1990 ◽  
Vol 151 (4) ◽  
pp. 415-422 ◽  
Author(s):  
Jack Maze ◽  
K. A. Robson ◽  
S. Banerjee ◽  
L. R. Bohm ◽  
R. K. Scagel
Author(s):  
Chester J. Calbick ◽  
Richard E. Hartman

Quantitative studies of the phenomenon associated with reactions induced by the electron beam between specimens and gases present in the electron microscope require precise knowledge and control of the local environment experienced by the portion of the specimen in the electron beam. Because of outgassing phenomena, the environment at the irradiated portion of the specimen is very different from that in any place where gas pressures and compositions can be measured. We have found that differential pumping of the specimen chamber by a 4" Orb-Ion pump, following roughing by a zeolite sorption pump, can produce a specimen-chamber pressure 100- to 1000-fold less than that in the region below the objective lens.


Author(s):  
D. R. Abrahamson ◽  
P. L. St.John ◽  
E. W. Perry

Antibodies coupled to tracers for electron microscopy have been instrumental in the ultrastructural localization of antigens within cells and tissues. Among the most popular tracers are horseradish peroxidase (HRP), an enzyme that yields an osmiophilic reaction product, and colloidal gold, an electron dense suspension of particles. Some advantages of IgG-HRP conjugates are that they are readily synthesized, relatively small, and the immunolabeling obtained in a given experiment can be evaluated in the light microscope. In contrast, colloidal gold conjugates are available in different size ranges and multiple labeling as well as quantitative studies can therefore be undertaken through particle counting. On the other hand, gold conjugates are generally larger than those of HRP but usually can not be visualized with light microscopy. Concern has been raised, however, that HRP reaction product, which is exquisitely sensitive when generated properly, may in some cases distribute to sites distant from the original binding of the conjugate and therefore result in spurious antigen localization.


Crisis ◽  
2011 ◽  
Vol 32 (4) ◽  
pp. 204-216 ◽  
Author(s):  
M. L. Rurup ◽  
H. R. W. Pasman ◽  
J. Goedhart ◽  
D. J. H. Deeg ◽  
A. J. F. M. Kerkhof ◽  
...  

Background: Quantitative studies in several European countries showed that 10–20% of older people have or have had a wish to die. Aims: To improve our understanding of why some older people develop a wish to die. Methods: In-depth interviews with people with a wish to die (n = 31) were carried out. Through open coding and inductive analysis, we developed a conceptual framework to describe the development of death wishes. Respondents were selected from two cohort studies. Results: The wish to die had either been triggered suddenly after traumatic life events or had developed gradually after a life full of adversity, as a consequence of aging or illness, or after recurring depression. The respondents were in a situation they considered unacceptable, yet they felt they had no control to change their situation and thus progressively “gave up” trying. Recurring themes included being widowed, feeling lonely, being a victim, being dependent, and wanting to be useful. Developing thoughts about death as a positive thing or a release from problems seemed to them like a way to reclaim control. Conclusions: People who wish to die originally develop thoughts about death as a positive solution to life events or to an adverse situation, and eventually reach a balance of the wish to live and to die.


1992 ◽  
Vol 85 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Maria-Jose Sanchez-Beltran ◽  
Juan Carbonell ◽  
Jose L. Garcia-Martinez ◽  
Isabel Lopez-Diaz

Fruits ◽  
2015 ◽  
Vol 70 (4) ◽  
pp. 201-212 ◽  
Author(s):  
Esther Aurora Ruiz Huerta ◽  
Judith Márquez Guzmán ◽  
Clara Pelayo Zaldívar ◽  
Claudia Barbosa Martínez ◽  
Leticia Ponce de León García

1974 ◽  
Vol 76 (1) ◽  
pp. 67-73 ◽  
Author(s):  
H. Agerbæk ◽  
S. E. Jensen

ABSTRACT In 129 patients with non-toxic goitre and 27 normal controls, thyroid dynamic patterns were estimated in an attempt to elucidate pathogenesis. The clinically euthyroid state was confirmed by measurement of PBI, T3-sephadex uptake and BMR. Thyroid clearance (th. cl.), plasma iodide (PII), and absolute iodine uptake (AIU) were determined and a perchlorate discharge test performed. Twenty patients (16%) had a high AIU and were thus suspected of having dyshormonogenesis; nine were thoroughly investigated and in six dyshormonogenesis was found. Both normals and non-toxic goitre patients had a low PII, but in the goitrous patients values were lowest. The thyroid clearance of iodide was significantly higher in the goitre patients, suggesting iodine deficiency to be a major aetiologic factor for goitre formation. AIU was higher in the goitre patients than in normals, suggesting a larger iodine leakage from the thyroid in these patients.


1997 ◽  
Vol 66 (2) ◽  
pp. 253-259 ◽  
Author(s):  
Shiping Wang ◽  
Goro Okamoto ◽  
Ken Hirano

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