On-orbit calibration techniques for optical payloads onboard remote-sensing satellites.

Errors in the attitude of optical payloads onboard remote-sensing satellites have a significant impact on image quality and high-precision quantification. This study presents two on-orbit calibration techniques for optical payloads. Self-calibration of the orientation of the optical axis of an optical payload can be achieved through on-orbit observation and imaging of star points based on the pinhole imaging principle. Separate on-orbit observation and imaging of star points can facilitate the mutual calibration of an optical payload and a star sensor as well as the correction of their installation errors. These two techniques are validated through ground and on-orbit satellite tests. The results show the following: The self-calibration error for a typical remote-sensing satellite is better than 0.2″ and the mutual-calibration error is better than 2″ for its optical payload and star sensor. Self-calibration and mutual calibration are effective for improving the calibration accuracy for the on-orbit orientation of optical payloads.

Ileal perforation caused by a fish bone shortly after drug-eluting stent implantation for acute myocardial infarction.

During the past century, the incidence of myocardial infarction has markedly increased worldwide. Percutaneous coronary intervention with stent implantation is often considered as the first-choice treatment, especially in emergency cases. Current guidelines recommend delayed elective noncardiac surgery for such vulnerable patients. However, few suggestions are available regarding the exact treatment strategy for patients who have already undergone percutaneous coronary intervention but suddenly need emergent noncardiac surgery for an unrelated reason. We herein present a case involving a patient with acute myocardial infarction who had undergone implantation of a drug-eluting stent and developed an ileal perforation due to fish bone ingestion 3 days postoperatively. After carefully balancing the risks of stent thrombosis and uncontrollable bleeding, dual antiplatelet therapy and low-molecular-weight heparin were given with close monitoring. Emergency laparotomy and partial small bowel resection surgery were then performed, after which the patient eventually recovered. This case indicates a possible management strategy for patients with acute myocardial infarction complicated by emergency noncardiac surgery.

Dronedarone and Amiodarone Induce Dyslipidemia and Thyroid Dysfunction in Rats.

BACKGROUND/AIMS: Amiodarone, a thyroid hormone-like molecule, can induce dyslipidemia and thyroid dysfunction. However, the effects of dronedarone on lipid metabolism and of both dronedarone and amiodarone on thyroid function and lipid metabolism remain unknown. METHODS: Fifty male Sprague-Dawley rats were randomly divided into 5 groups (10 in each group): normal control (NC), amiodarone-treated (AMT), dronedarone-treated (DRT), rats treated with amiodarone combined with polyene phosphatidylcholine (AC), and rats treated with dronedarone combined with polyene phosphatidylcholine (DC). Rats were given amiodarone (120 mg/kg/d), dronedarone (120 mg/kg/d), and polyene phosphatidylcholine (200 mg/kg/d) for 13 weeks. At the end of weeks 4, 8, 12, and 13, plasma-free triiodothyronine (FT3), free thyroxine (FT4), triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) were determined. At the end of this protocol, rats were sacrificed and the thyroid glands were isolated, weighed, and examined histopathologically. The protein expression of Bcl-2 was measured by immunochemical staining. The mRNA expression of thyroglobulin (Tg), type-1 deiodinase (D1), and thyroid peroxidase (TPO) were detected by polymerase chain reaction (PCR). RESULTS: Compared with the NC group, FT3 and FT4 levels in the DRT and DC groups significantly increased at week 4 but declined thereafter. The AMT and AC groups had lower FT3 levels but comparable FT4 levels. The levels of TG, LDL-c, and HDL-c in the NC group were lower than those in the other groups whereas the LDL-c/HDL-c ratio was lowest in the AMT group. Bcl-2 expression significantly increased in the DRT group. The mRNA expression of Tg increased whereas the mRNA expression of D1 decreased. Dronedarone induced hyperthyroidism at the early stage and hypothyroidism at the late stage whereas amiodarone only caused hypothyroidism. CONCLUSION: Both dronedarone and amiodarone can induce dyslipidemia and increase the levels of TC, LDL-c, and HDL-c, and these effects may be associated with thyroid dysfunction.