806 research outputs found

    Guidance applications of a quasi-optimum control technique Final report

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    Quasi-optimal control technique for orbital injection guidanc

    Additional studies of quasi-optimum feedback control techniques

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    Quasi-optimal control technique for space vehicle attitude, bounded acceleration rendezvous in free space, and aircraft landing proble

    Prostaglandins in breast cancer: relationship to disease stage and hormone status.

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    Tissue prostaglandin (PG) content and production by human breast cancers were measured in 24 human mammary carcinoma specimens. The 5 compounds studied were PGE1, PGE2, PGF2 alpha, 6-keto-PGF1 alpha, and TXB2. The tissue content of all 5 compounds was higher in neoplastic tissue in comparison with the paired noncancerous breast tissue. However, microsomal PG synthetase activity in vitro in noncancerous and neoplastic breast tissue was comparable. Increased thromboxane formation was associated with three clinical variables--tumour size, axillary lymph node metastases and distant metastasis. A lesion negative for either oestrogen or progesterone receptor content tended to produce more TXB2 but lower PGE2 and 6-keto-PGF1 alpha. Results obtained in this pilot study may provide clues as to what direction future larger studies could take in the search for reliable prognostic indicators for breast cancer

    Triage Considerations for Patients Referred for Structural Heart Disease Intervention During the Coronavirus Disease 2019 (COVID-19) Pandemic: An ACC /SCAI Consensus Statement

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    The COVID-19 pandemic has strained health care resources around the world causing many institutions to curtail or stop elective procedures. This has resulted in the inability to care for patients valvular and structural heart disease (SHD) in a timely fashion potentially placing these patients at increased risk for adverse cardiovascular complications including congestive heart failure and death. The effective triage of these patients has become challenging in the current environment as clinicians have had to weigh the risk of bringing susceptible patients into the hospital environment during the COVID-19 pandemic versus the risk of delaying a needed procedure. In this document, we suggest guidelines as to how to triage patients in need of SHD interventions and provide a framework of how to decide when it may be appropriate to proceed with intervention despite the ongoing pandemic. In particular, we address the triage of patients in need of trans-catheter aortic valve replacement and percutaneous mitral valve repair. We also address procedural issues and considerations for the function of structural heart disease teams during the COVID-19 pandemic

    Fertility preservation in female classic galactosemia patients

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    Almost every female classic galactosemia patient develops primary ovarian insufficiency (POI) as a diet-independent complication of the disease. This is a major concern for patients and their parents, and physicians are often asked about possible options to preserve fertility. Unfortunately, there are no recommendations on fertility preservation in this group. The unique pathophysiology of classic galactosemia with a severely reduced follicle pool at an early age requires an adjusted approach. In this article recommendations for physicians based on current knowledge concerning galactosemia and fertility preservation are made. Fertility preservation is only likely to be successful in very young prepubertal patients. In this group, cryopreservation of ovarian tissue is currently the only available technique. However, this technique is not ready for clinical application, it is considered experimental and reduces the ovarian reserve. Fertility preservation at an early age also raises ethical questions that should be taken into account. In addition, spontaneous conception despite POI is well described in classic galactosemia. The uncertainty surrounding fertility preservation and the significant chance of spontaneous pregnancy warrant counseling towards conservative application of these techniques. We propose that fertility preservation should only be offered with appropriate institutional research ethics approval to classic galactosemia girls at a young prepubertal age
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