The snRNP core protein SmB and tissue-specific SmN protein are differentially distributed between snRNP particles

The SmN protein is a tissue specific component of the small nuclear ribonucleoprotein particle which is closely related to the ubiquitously expressed SmB protein but is expressed only in the brain and heart. To investigate the function of SmN, its localisation within different snRNP particles was investigated using a range of anti-snRNP monoclonal antibodies. SmN and SmB were found to exhibit different patterns of association with snRNP particles in two cell lines, ND7 and F9 which express SmN. In both cases, SmN was found to be present in the U-2 snRNP but was excluded from the U-1 snRNPs whereas SmB was present in both U-1 and U-2 snRNPs. Data from transfected 3T3 mouse fibroblasts cell lines artificially expressing a low level of SmN also confirm this observation. In contrast, SmN was found to be an integral component of both the U-1 and U-2 snRNPs in both 3T3 cells artificially expressing high levels of SmN and in adult rat brain which has a naturally high level of SmN expression. Taken together, the results suggest that the pre-U1 snRNP particle has a lower affinity for SmN than for SmB. Thus, SmN expressed at low levels incorporates into U2, but SmN expressed at high levels incorporates into both U1 and U2 snRNPs and replaces SmB. The significance of these effects is discussed in terms of the potential role played by SmN in constitutive and alternative splicing pathways in neuronal cells.     

Information technology enhanced learning in distance andconventional education

The rapid growth of the Internet and the media-rich extensions of the World Wide Web allow new developments in the way instructors transfer knowledge to their students. There is no doubt that nothing will replace synchronous learning through face to face interaction but it is sometimes not feasible for students to attend conventional classes due to distance or time constraints. This paper presents a model for using information technology to enhance the learning experience for conventional on-campus students, as well as for those students whose circumstances require that they be asynchronous in time or space. The approach described emphasizes a solution which allows students to attend the class in real time via the Internet, or to access asynchronously digitally stored video material with hyperlinks to online training resources at any time. The proposed solution permits interaction in real-time and asynchronously among students and between students and instructor, which is a key for effective learning. In addition, the instructor maintains a significant level of spontaneity in using multimedia material prepared in advance or using conventional chalkboard or hand written materials via traditional overhead projection. The paper describes the technical issues involved and the chosen solutions to provide enhanced live and archived classes. This paper provides some comments on the evaluation of the learning experience using this method of delivery for on-campus and distance education students. Finally the authors share their vision on future trends to improve the proposed learning environment and the need for an optimal balance between expositive teaching and active learning for both synchronous and asynchronous activities     

A common pathway mediates retinoic acid and PMA-dependent programmed cell death (apoptosis) of neuronal cells

To assess the maternal and neonatal risk associated with high-order cesarean sections, a case-control study was carried out in two university affiliated maternity wards. The outcome of 154 pregnancies of women undergoing cesarean section for the 4th time or more was compared with 148 women sectioned for the 2nd or 3rd time and 132 women of similar age and parity after spontaneous birth. The main outcome measures were maternal operative and postoperative morbidity and neonatal prematurity and its complications, Apgar scores, and the need for intensive care. Women undergoing multiple (> or = 4) cesarean sections had significantly more intra-abdominal adhesions (P < 0.0001) than women sectioned for the 2nd or 3rd time. However, the time interval from incision to delivery and the total duration of operation were similar. The postoperative course was not adversely affected by multiple cesarean sections. A high incidence (16.2%) of preterm cesarean deliveries was noted in the study group. This was due to non-elective repeat cesarean delivery rather than to poor timing of scheduled cesarean sections. The significantly increased (P < 0.05) need for neonatal intensive care was explained by the higher occurrence of prematurity. Low Apgar scores (< or = 7) at 1 and 5 min were significantly (P < 0.01) related to multiple cesarean sections, even after controlling for the effect of gestational age. We conclude that multiple cesarean sections pose little risk for the mother, but may be associated with increased neonatal risk, attributed mainly to preterm non-elective cesarean sections.     

Elevated soluble fas production in SLE correlates with HLA status not with disease activity

CONTEXT: Medical educators have had a growing sense that proficiency in physical diagnostic skills is waning, but few data have examined the question critically. OBJECTIVE, DESIGN, AND SETTING: To compare the cardiac auscultatory proficiency of medical students and physicians in training. A multicenter cross-sectional assessment of students and house staff. A total of 8 internal medicine and 23 family practice programs of the mid-Atlantic area. PARTICIPANTS: A total of 453 physicians in training and 88 medical students. INTERVENTIONS: All participants listened to 12 cardiac events directly recorded from patients, which they identified by completing a multiple-choice questionnaire. MAIN OUTCOME MEASURES: scores were expressed as the percentage of participants, for year and type of training, who correctly identified each event. Cumulative scores were expressed as the total number of events correctly recognized. An adjusted score was calculated whenever participants selected not only the correct finding but also findings that are acoustically similar and yet absent. RESULTS: Trainees' cumulative scores ranged between 0 and 7 for both internal medicine and family practice residents (median, 2.5 and 2.0, respectively). Internal medicine residents had the highest cumulative adjusted scores for the 6 extra sounds and for all 12 cardiac events tested (P=.01 and .02, respectively). On average, internal medicine and family practice residents recognized 20% of all cardiac events; the number of correct identifications improved little with year of training and was not significantly higher than the number identified by medical students. CONCLUSIONS: Both internal medicine and family practice trainees had a disturbingly low identification rate for 12 important and commonly encountered cardiac events. This study suggests a need to improve the teaching and assessment of cardiac auscultation during generalists' training, particularly with the advent of managed care and its search for more cost-effective uses of technology.     

The expression of constitutively active isotypes of protein kinase C to investigate preconditioning

The role of protein kinase C (PKC) in ischemic preconditioning remains controversial because of difficulties with both its measurement and pharmacological manipulation. We investigated preconditioning in isolated neonatal rat cardiocytes by expressing constitutively active isotypes of PKC. Observations at differing durations of simulated ischemia suggested beta-galactosidase (beta-gal) activity reflected viability within transfected myocytes. Preconditioning with 90 min of ischemia significantly increased beta-gal activity and myocyte survival after 6 h of ischemia; an effect abolished by PKC inhibitors. After co-transfection with plasmids encoding beta-gal and either constitutively active mutants of PKC-delta, PKC-alpha, wild type PKC-delta, or empty vector, cardiocytes were subjected to 6 h of ischemia. Only PKC-delta, rendered constitutively active by a limited deletion within the pseudosubstrate domain, consistently increased resistance to simulated ischemia (beta-gal activity was 85.6 +/- 11.9% versus 53.7 +/- 6.5% (p 相似文献   

Frequency sweeping tests for stability independent of delay

In this paper we study the stability properties of linear time-invariant delay systems given in a state space form. We consider specifically the notion of asymptotic stability independent of delay. Systems with both commensurate and noncommensurate delays are investigated. We present for each class of systems a necessary and sufficient condition in terms of structured singular values, and further we demonstrate how these conditions may be extended to study stability independent of delay for uncertain systems. Our results consist of several frequency sweeping tests that can be systematically implemented and that should complement the previous work     

A comparative performance study of wireless and power line networks

Local area networks based on the IEEE 802.11a/b wireless networking standards and emerging power line communication (PLC) standards are attractive for establishing networks with no new wires for in-home and business applications. This article presents a theoretical performance comparison of the 802.11 a/b and HomePlug 1.0 PLC protocols. The article also presents comprehensive comparative field test results addressing such issues as coverage, channel stability, and reliability as well as the associated implications on the capability of these technologies to provide QoS support for multimedia traffic in typical residential settings.     

Bringing the Classroom to Students Everywhere

In this paper we present a technique for enabling students to benefit from the traditional classroom experience by joining classes live on the Internet or by taking lectures on demand asynchronously. The proposed “lectures on demand” paradigm is shown to be an effective component in the now well established framework of Asynchronous Learning Networks. Video and audio from traditional face‐to‐face lectures are synchronized with class materials such as PowerPoint® slides and provided as streaming multimedia content via the Internet. Some comments are given on the issues involved in using this methodology at the University of Florida to offer online courses towards MS and BS degrees.     

Hands‐On Laboratory Experiments in Flexible and Distance Learning

The advent of the Internet as a major communication channel has triggered a great deal of interest in real‐time services such as broadcast or interactive audio and video services. In this paper, a further step into the realm of real‐time services over the Internet is presented, namely, synchronous access to remote and distributed laboratory facilities. The proposed approach demonstrates the feasibility of using remote laboratory experiments to complement and enhance traditional as well as on‐line courses in control engineering education. The distributed laboratory effectively enables students to reinforce their learning through hands‐on studies carried out in a flexible environment.