Transition layer thickness in microlaminar deposits

A theoretical analysis was carried out on the change of composition of a deposit obtained by the dual pulse method of forming laminar metal foils, with transition from a low current to a high current pulse, both in the galvanostatic and the potentiostatic mode of deposition. It was shown that the existence of a transition layer of varying composition between a layer of pure metal 1 and a layer consisting predominantly of the metal 2 is an inherent consequence of the electrochemical process, primarily because of an induction period in the concentration polarization with respect to ions of metal 1. The importance of this transition layer increases as the thickness of the layers of the two metals decreases. Eventually this limits the possibility of obtaining a sharp boundary between the layers, when the nanometre region of layer thickness is reached. Equations are given for calculating the deposition current density and rate of stirring of the electrolyte which provide a deposit of a required level of metal 1 in the layer of metal 2, as well as a required sharpness of the boundary between two layers. Experimental proof of the correctness of the analysis was sought. It was found that significant changes in the properties of the deposit occur in the same range of layer thickness in which the transition of the composition takes places.Nomenclature _c,1, a_c,2 transfer coefficient of the cathodic processes - C interfacial capacitance - C₁, C₂ concentration of the ions of metals 1 and 2 at the interface r - C ₀ ¹ , C ₀ ² concentration of ions of the metals 1 and 2 in solution - D ₁ diffusion coefficient for the diffusion of ions of the metal 1 - E _r,1,E _r,2 reversible potentials of metals 1 and 2, respectively - F the Faraday constant - J ₀ ¹ ,J ₀ ² exchange current density of the metals 1 and 2, respectively - M ₁,M ₂ atomic weights of the metals 1 and 2, respectively - kinematic viscosity of solution - ₁, ₂ densities of the metals 1 and 2 respectively - rotation speed (r.p.s.) - z number of electrons exchanged in the deposition process This paper is dedicated to Professor Brian E. Conway on the occasion of his 65th birthday, and in recognition of his outstanding contribution to electrochemistry.     

Behavioral training for parents of retarded children: alternative formats based on instructional manuals

A series of instructional manuals in behavior modification with retarded children was tested as a self-contained resource and as part of three larger training programs involving different amounts of professional assistance to parents: telephone consultations, training groups, training groups plus home visits. One hundred and sixty families were randomly assigned to the four training conditions or to a delayed-treatment control group. The 20-week treatment period emphasized the programming of self-help skills, but also provided an introduction to programming language skills and managing behavior problems. The manuals-alone format was as effective as the more expensive training formats in producing gains in children's self-help skills and fostering knowledge of behavioral principles in mothers. The two group-training formats produced more efforts at behavior-problem management, greater gains in knowledge of principles by fathers, and higher self-confidence as teachers. Telephone consultation was generally the least effective training format; the manuals-alone condition was surprisingly effective. Some implications of the results for future strategies of family intervention were discussed.     

Role of estradiol-17 beta and progesterone in regulating constriction of ovine uterine arteries

Fistulas between the abdominal aorta and renal vein are exceedingly rare. Diagnostic delays are not unusual. Correction can be extremely difficult because of anatomical distortion and size of the arterialized veins. A young woman with such a fistula following a gunshot wound is presented. Four years following injury, the fistula was repaired successfully during intentional arrest of the circulation for 7 minutes. This was accomplished with deep hypothermia and cardiopulmonary bypass. No serious problems occurred during the operation. The patient tolerated the procedure well and has been relieved of her symptoms completely. Most patients with traumatic or spontaneous arteriovenous fistulas can be managed safely and effectively by conventional operative techniques. In selected situations, the risk of total circulatory arrest and deep hypothermia may be less than the risk of uncontrollable bleeding inherent in conventional techniques. Suggested indications for use of total circulatory arrest in vascular surgery are (1) inability to achieve vascular control by more conventional means, (2) massive distention of regional veins as occurrs in well established fistulas of the trunk, (3) one or more prior corrective attempts with use of conventional techniques, and (4) anticipated anatomical distortion and/or multiple abnormal vascular communications. This technique is a valuable approach to the correction of otherwise inoperable cardiovascular lesions.     

Family planning knowledge, attitudes and practices in women with schizophrenic spectrum disorders

This study set out to test three hypotheses about family planning in women with schizophrenic spectrum disorders, as compared to demographically comparable non-mentally ill control women: that they (1) report at least as much unprotected intercourse while not desiring pregnancy; (2) have less knowledge about contraception; and (3) perceive more, and different, obstacles to obtaining or using birth control. A semistructured Family Planning Interview was administered to subjects (n = 44) with Research Diagnostic Criteria diagnoses of schizophrenia and schizoaffective disorder, and to non-mentally ill control subjects (n = 50). The participants had high rates of unprotected intercourse, as did non-mentally ill controls. They had significantly less reproductive and contraceptive knowledge than the control subjects, and were more likely to perceive birth control as difficult to obtain. The most common reason women with schizophrenic spectrum disorders gave for failing to use birth control was that they did not expect to have sex, while that given by non-mentally ill subjects related to side-effects of birth control. Important obstacles to family planning in women with schizophrenic spectrum disorders include relative lack of knowledge and difficulty planning ahead. Although many women with schizophrenia could benefit from long-acting, reversible contraception, many may be unaware of those options and/or may find them difficult to obtain. Integrating family planning with mental health care might better address the unique needs of this population.     

Fluoride stimulation of the rat parathyroid gland: an ultrastructural study

The parathyroid glands of rats given 150 ppm fluoride in the drinking water for 10 weeks are evaluated ultrastructurally and compared to the parathyroid glands of untreated rats. As a result of fluoride ingestion, the majority of the parathyroid cells are dark chief cells, indicating that these cells are in the active stages of the secretory cycle. More significantly, in the fluoride-treated rats, the cytoplasmic organelles of the dark chief cells are even more developed that those seen in the dark chief cells of untreated rats. The dark cells contain an electron-dense cytoplasm with abundant lamellar arrays of rough endoplasmic reticulum, spiral aggregations of free ribosomes, multiple dilated Golgi complexes, and increased numbers of secretory granules. The cells are at a minimum dimension with maximum tortuosity of the plasma membranes; and, as a result, large intercellular spaces are often seen between contiguous cells. Based on these observations, it is suggested that, in the fluoride-treated rat, a type of secondary hyperparathyroidism develops resulting in an increase in the organelles involved in protein synthesis and secretion.     

Cardiovascular effects of microinjections of opioid agonists into the ''Depressor Region'' of the ventrolateral periaqueductal gray region

Differentiating the binding properties of applied lectins should facilitate the selection of lectins for characterization of glycoreceptors on the cell surface. Based on the binding specificities studied by inhibition assays of lectin-glycan interactions, over twenty Gal and/or GalNAc specific lectins have been divided into eight groups according to their specificity for structural units (lectin determinants), which are the disaccharide as all or part of the determinants and of GalNAc alpha 1-->Ser (Thr) of the peptide chain. A scheme of codes for lectin determinants is illustrated as follows: (1) F (GalNAc alpha 1-->3GalNAc), Forssman specific disaccharide--Dolichos biflorus (DBL), Helix pomatia (HPL) and Wistaria floribunda (WFL) lectins. (2) A (GalNAc alpha 1-->3 Gal), blood group A specific disaccharide--Codium fragile subspecies tomentosoides (CFT), Soy bean (SBL), Vicia villosa-A4 (VVL-A4), and Wistaria floribunda (WFL) lectins. (3) Tn (GalNAc alpha 1-->Ser (Thr) of the protein core)--Vicia villosa B4 (VVL-B4), Salvia sclarea (SSL), Maclura pomifera (MPL), Bauhinia purpurea alba (BPL) and Artocarpus integrifolia (Jacalin, AIL). (4) T (Gal beta 1-->3GalNAc), the mucin type sugar sequences on the human erythrocyte membrane(T alpha), T antigen or the disaccharides at the terminal nonreducing end of gangliosides (T beta)--Peanut (PNA), Bauhinia purpurea alba (BPL), Maclura pomifera (MPL), Sophora japonica (SJL), Artocarpus lakoocha (Artocarpin) lectins and Abrus precatorius agglutinin (APA).(5) I and II (Gal beta 1-->3(4)GlcNAc)--the disaccharide residue at the nonreducing end of the carbohydrate chains derived from either N- or O-glycosidic linkage--Ricinus communis agglutinin (RCA1), Datura stramonium (TAL, Thorn apple), Erythrina cristagalli (ECL, Coral tree), and Geodia cydonium (GCL). (6) B (Gal alpha 1-->3Gal), human blood group B specific disaccharide--Griffonia(Banderiaea) simplicifolia B4 (GSI-B4). (7) E (Gal alpha 1-->4Gal), receptors for pathogenic E. coli agglutinin, Shiga toxin and Mistletoe toxic lectin-I (ML-I) and abrin-a.     

The family history component of cancer genetic risk counseling

This study evaluated effective resistances on the ventricular surfaces of arterially-perfused rabbit hearts. Effective resistances were determined with a four-electrode array that was parallel or perpendicular to epicardial fibers. Resistance along or across epicardial fibers was determined by applying current to the epicardium with two parallel line electrodes and measuring potentials in the region between the electrodes. Computer simulations were performed to gain insight into the distribution of current in the ventricular wall. The effective resistances were not different along versus across fibers. Simulations showed that transmural rotation of fibers causes current to be distributed differently when the electrode is oriented perpendicular versus parallel to epicardial fibers. When the array is oriented so that epicardial current is across fibers, the fraction of current that flows transmurally and along the deeper fibers increases while the fraction of current that flows epicardially decreases. This introduces isotropy of the effective resistance. Thus, in contrast to isolated cardiac fibers, the ventricular epicardium exhibits isotropic effective resistance due to transmural rotation of fibers. The rotation and isotropic resistance may be important for cardiac electrical behavior and effects of electrical current in the ventricles.