Introduction: Acute mesenterial ischemia belongs to diagnosis of acute abdomen and if left untreated, leads to death of a patient. The problem is in early diagnosis. Case report: Authors present a case of long-lasting acute mesenterial ischemia which was caused by thrombotic closure of upper mesenteric artery. Diagnosis and therapy is described in the text. Discussion: Diagnosis of acute mesenterial ischemia is often difficult. There are no biochemical markers that would be sufficiently specific for the diagnosis. CT angiography yields best results in imaging methods. The intervention is the next step after the examination. In acute state, usually radiologic intervention is the method of choice. Surgical intervention is indicated in case of intestinal necrosis. The range of resection has to be maximally saving. In the event of uncertainty concerning intestine vitality, second look operation is indicated. Conclusion: Acute mesenterial ischemia is a serious disease and only early diagnosis and interdisciplinary cooperation gives a chance to successfully treat a patient.
It is well-known that the applicability of phthalocyanine chemiresistors suffers from long recovery time after NO2 exposure. This circumstance enforces the necessity to operate the sensors at elevated temperatures (150-200 °C), which shortens the sensor lifetime and increases its power consumption (regardless, a typical measurement period is longer than 15 min). In this paper, we propose a new method for fast and effective recovery by UV-vis illumination at a low temperature (55 °C). The method is based on short illumination following short NO2 exposure. To support and optimize the method, we investigated the effects of light in the wavelength and intensity ranges of 375-850 nm and 0.2-0.8 mW/mm2, respectively, on the rate of NO2 desorption from the phthalocyanine sensitive layer during the recovery period. This investigation was carried out for a set of phthalocyanine materials (ZnPc, CuPc, H2Pc, PbPc, and FePc) operating at slightly elevated temperatures (55-100 °C) and was further supported by the analysis of UV-vis and FTIR spectral changes. We found out that the light with the wavelength shorter than 550 nm significantly accelerates the NO2 desorption from ZnPc, CuPc, and FePc, and allows bringing the measurement period under 2 min and decreasing the sensor power consumption by 75%. Possible mechanisms of the light-stimulated desorption are discussed.
- MeSH
- isoindoly chemie účinky záření MeSH
- oxid dusičitý chemie MeSH
- světlo MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
