Multi-center bonds as resonance hybrids: A real space perspective

The concept of distinct bonds within molecules has proven to be successful in rationalizing chemical reactivity. However, bonds are not a well-defined physical concept, but rather vague entities, described by different and often contradicting models. With probability density analysis, which can-in principle-be applied to any wave function, bonds are recovered as spin-coupled positions within most likely electron arrangements in coordinate space. While the wave functions of many systems are dominated by a single electron arrangement that is built from two-center two-electron bonds, some systems require several different arrangements to be well described. In this work, a range of these multi-center bonded molecules are classified and investigated with probability density analysis. The results are compared with valence bond theory calculations and data from collision-induced dissociation experiments.

Human is what is born of a human: personhood, rationality, and an European convention

In the course of its preparation, the 1997 convention on human rights and biomedicine adopted by the Council of Europe instigated a widespread debate. This article examines one of the core issues: the notion of the human being as depicted in the convention. It is argued that according to the convention, this being may exist in three different legal categories, namely 'human life', 'embryo', and 'personhood', each furnished with an inherent set of somewhat different rights, yet none of them clearly defined, thus leaving it to domestic law to regulate at what point a human being belongs to which category. While this approach is understandable from a political point of view, it creates a vicious circle, since law thereby has to define its own foundation and, in the case of the convention, to protect a being that it cannot define. It appears that this form of life is seen rather as a given entity, taking precedence over the interests of society and science, and its dignity and identity forming criteria for the subsequent systems of culture, simply because this life is human and nothing else. Thus, the convention approaches a natural law position.

[Standardization of the Kent Infant Development Scale: implications for primary care pediatricians]

OBJECTIVE

The purpose of this study was the standardization of an infant assessment protocol based on behavioral observations of Spanish parents. The Kent Infant Development (KIDS) scale was translated into Spanish and named "Escala de Desarrollo Infantil de Kent" (EDIK).

PATIENTS AND METHODS

The EDIK normative data were collected from the parents of 662 healthy infants (ages 1 to 15 months) in pediatric clinics. Infants born more than 2 weeks premature or who had serious physical or neurological illness were not included.

RESULTS

EDIK raw scores of Spanish infants were converted to developmental ages by comparing them with the number of behaviors for each age group in the normative sample. We obtained the mean score and standard deviation for the full scale and different domains (cognitive, motor, social, language, and self-help).

CONCLUSIONS

This study shows that EDIK is sensitive to differences in ages and a good instrument that allows one to make a classification between normal infants or those at risk. It should prove useful in developmental pediatric practice.

Success rates following intracytoplasmic sperm injection are improved by using ZIFT vs IVF for embryo transfer

PURPOSE

The purpose of this study was to analyze whether the mode of embryo transfer (ZIFT vs IVF) affected the outcome in intracytoplasmic sperm injection (ICSI) cycles.

METHODS AND RESULTS

Eighty-two ICSI cycles (42 ZIFT and 40 IVF) were analyzed. Several variables, including patient age and weight, numbers of mature eggs collected, injected, and fertilized, fertilization rate, number of fertilized eggs obtained per cycle, numbers of zygotes/embryos transferred, clinical pregnancy rate, and implantation rate, were compared. Mean patient age and weight were identical. The mean number of mature eggs collected and injected and fertilization rate were significantly higher in the ZIFT group, however, the mean numbers of zygotes/embryos transferred were identical. The clinical pregnancy and implantation rates in ZIFT cycles (52.3 and 23.2% respectively) were significantly higher than in IVF cycles (17.5 and 9.7%).

CONCLUSIONS

These data suggest that ZIFT is the more appropriate method for transfer of ICSI-derived embryos.

[A new method for evaluating psychomotor development based on information from parents. The Spanish version of the Kent Infant Development Scale]

OBJECTIVE

The purpose of this dissertation research was to design, standardize and validate the Spanish version of the Kent Infant Development Scale (KIDS).

PATIENTS AND METHODS

This questionnaire is based on information obtained from the parents. It was translated into Spanish and named "Escala de Desarrollo Infantil de Kent" (EDIK). The EDIK normative data were collected from the parents of 662 healthy infants (ages 1 to 15 months) in pediatric clinics in Catalonia (Spain).

RESULTS

Test-retest reliability (r = 0.99; p < 0.001), interjudge reliability (r = 0.98; p < 0.001) and internal consistency (Cronbach alpha = 0.9947) were determined. An "r' of 0.96 was obtained when EDIK scores were compared to their estimated developmental ages obtained from the Denver Developmental Scale. The correlation of the infants' chronological age and their EDIK was 0.96 (p < 0.001).

CONCLUSIONS

The high reliability and validity correlation coefficients demonstrate the sound psychometric properties of the EDIK. It appears to be a useful and acceptable instrument in measuring the developmental status of infants by using the reports of their parents.