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Biomedical subjects

B Sandow

Publications and source records attributed to B Sandow.

7 recordsLinked to original sources
PubMed2001

Electronic correlation effects and the Coulomb gap at finite temperature.

We have investigated the effect of the long-range Coulomb interaction on the one-particle excitation spectrum of n-type germanium, using tunneling spectroscopy on mechanically controllable break junctions. At low temperatures, the tunnel conductance shows a minimum at zero bias voltage due to the Coulomb gap. Above 1 K, the gap is filled by thermal excitations. This behavior is reflected in the variable-range hopping resistivity measured on the same samples: up to a few degrees Kelvin the Efros-Shklovskii lnR infinity T(-1/2) law is obeyed, whereas at higher temperatures deviations from this law occur. The type of crossover differs from that considered previously in the literature.

Journal Article↗
PubMed1984

In vitro fertilization in Norfolk, Virginia, 1980-1983.

Three years of progress of the Vital Initiation of Pregnancy (VIP) Program in Norfolk is reported. No conception resulted from 41 oocyte aspirations during spontaneous menstrual cycles in 1980. An average of 3.7 oocytes per cycle, or a 73.5% recovery rate, resulted in 362 human menopausal gonadotropin/human chorionic gonadotropin-induced cycles from January 1981 to March 1983. Forty percent of the oocytes recovered from these cycles were preovulatory, 35% atretic, and 25% immature. Immature oocytes were often matured in vitro, fertilized, and found to produce pregnancies. A total of 62 pregnancies occurred, which represents a 17 or 23% pregnancy rate, based on laparoscopies or embryo transfers, respectively. There were 11 preclinical and 7 clinical miscarriages. Twenty-nine normal babies have been delivered, including a set of twins. The remainder appears to be normally progressing pregnancies. Polyspermia was observed in 8.8% of the fertilizable oocytes.

Adult↗
PubMed1984

Correlation of human menopausal gonadotropin/human chorionic gonadotropin stimulation and oocyte quality in an in vitro fertilization program.

One hundred forty-seven cycles in normal ovulatory patients are reported. All were stimulated with human menopausal/human chorionic gonadotropin. Three estrogen responses were identified: normal, high, and low. Patients who achieved pregnancy formed a fourth category, the pregnancy group. The number of preovulatory and immature oocytes, the preovulatory and immature oocytes that fertilized normally or abnormally, the ones that cleaved in culture, and the ones that were transferred were used as parameters to compare quality of the oocytes in each of the estrogen responders. No significant differences were found in any of them. Abnormal zonae pellucidae are described as possibly due to overmaturation of the follicle. No significant difference in the proportion of abnormal zonae in the different categories was found.

Adult↗
PubMed1983

The importance of the follicular phase to success and failure in in vitro fertilization.

One hundred seventy-five cycles in patients with irreparable tubal disease were stimulated by human menopausal gonadotropin/human chorionic gonadotropin for the purpose of in vitro fertilization. As judged by the height of the peripheral estradiol response, the patients were classified as high, intermediate, or low responders. In addition, the estradiol pattern of the response was found to be separable into six categories. The pregnancy rate was found to be related to the height and to the pattern of peripheral response. The overall pregnancy rate in this consecutive series was 19% but varied according to the height and pattern of response from 40% to 0%.

Estradiol↗
PubMed1982

The program for in vitro fertilization at Norfolk.

Several aspects of the program of in vitro fertilization (IVF), or, as it is called in Norfolk, the program for the Vital Initiation of Pregnancy (VIP), have been or are in the process of publication. However, because there has been no overall account, it seems appropriate to give a brief report of a general nature covering the period from the beginning of the effort in late February 1980 through December 31, 1981. Although minor changes were constantly made in the protocol, there were two major revisions. Therefore, a discussion of the program during three distinct periods, i.e., 1980, 1981-Phase I, and 1981-Phase II, is necessary. During 1980 and 1981 all patients had either no fallopian tubes or irreparable tubes.

Adolescent↗
PubMed1976

Direction-of-turn stereotypes - conflict and concord.

Three principles are described which affect the design of 'workable' control-display relations for vertical linear displays with a rotary control. These principles facilitate each other with some control-display configurations, strengthening the stereotyped expectation for the effect of a particular control movement. In other configurations the principles oppose each other; here 'Warrick's Principle' emerges as strongest but is weakened by the opposing action of an alternative principle.

Journal Article↗