Observation of Rayleigh-Lamb waves generated by the 2022 Hunga-Tonga volcanic eruption with the POLA detectors at Ny-Ålesund.

The eruption of the Hunga-Tonga volcano in the South Pacific Ocean on January 15, 2022, at about 4:15 UTC, generated a violent explosion, which created atmospheric pressure disturbances in the form of Rayleigh-Lamb waves detected all over the globe. Here we discuss the observation of the Hunga-Tonga shock-wave performed at the Ny-Ålesund Research Station on the Spitsbergen island, by the detectors of the PolarquEEEst experiment and their ancillary sensors. Online pressure data as well as the results of dedicated offline analysis are presented and discussed in details. Results include wave arrival times, wave amplitude measurements and wave velocity calculation. We observed five passages of the shock wave with a significance larger than 3 [Formula: see text] and an amplitude up to 1 hPa. The average propagation velocity resulted to be (308 ± 0.6) m/s. Possible effects of the atmospheric pressure variation associated with the shock-wave multiple passages on the cosmic-ray rate at ground level are also investigated. We did not find any significant evidence of this effect.

Existence of ipsilateral hemiparesis in ischemic and hemorrhagic stroke: two case reports and review of the literature.

Supratentorial stroke presenting as contralateral hemiparesis is predominantly related to contralateral projection of the corticospinal tract. While most corticospinal fibers decussate at the level of the medulla, some tracts continue descending as ipsilateral ventral corticospinal fibers. In this systematic review of the literature and 2 case reports specifically seen in our institute, we describe the presence of ipsilateral hemiparesis in ischemic and hemorrhagic stroke patients. We compiled available information about the existence of uncrossed corticospinal tracts and/or the presence of bilateral operating motor cortical networks. There was an association in patients with congenital uncrossed corticospinal tracts and posterior fossa malformations. There was also a high correlation of ipsilateral hemiparesis in patients with remote infarction. A previous stroke was seen in 50% of the patients, all except for 1 case were ischemic in nature. Patients with previous infarcts do demonstrate an adaptive compensation for damaged or disconnected regions of an injured area. This emphasizes the need to consider the investigation for previous infarctions or underlying genetic structural defects by using certain imaging modality.

Sarcoma of the aorta: report of a case and review of the literature.

Tumors of the aorta are extremely rare and usually malignant. We report the case of a sarcoma of the infrarenal aorta in a 67-year-old man. Initial symptoms were metastatic cutaneous nodules and lower extremity claudication. Aortography and computerized tomography of the abdomen revealed a fungating mass obstructing the aortic bifurcation. Treatment consisted of resection of the aorta, aortobiiliac bypass, and combined radiation and chemotherapy. Death occurred six months after treatment. Twenty-seven cases of angiosarcoma reported in the literature are reviewed.

Goiter with severe respiratory compromise: evaluation and treatment.

Goiter with major respiratory compromise is uncommon but troublesome. Evaluation and treatment of this condition are controversial. Of a total of 2,908 goiters operated on over a 17-year period, 58 cases with this particular complication were studied retrospectively to define optimal management. Twenty-two patients had severe or acute dyspnea, and four of them required immediate tracheal intubation. Thirty-six patients had chronic dyspnea without cyanosis. Carcinoma was present in these two groups in 50% and 11% of patients, respectively. Results of our retrospective study are as follows: long-standing tolerance of goiter did not preclude the possibility of compressive respiratory distress or carcinoma. Optimal management of goiter with respiratory compression was obtained when surgery was delayed until satisfactory operating room conditions and adequate possibilities of interpretation of pathologic conditions were united. In case of respiratory distress, tracheal intubation allowed to abide without risks. In other patients preoperative investigations were kept to a minimum. Technical artifices facilitated the extraction of the goiter via cervicotomy without sternotomy in 92% of patients with minimal morbidity. Whenever necessary, endotracheal intubation obviated the need for tracheostomy. These data suggest preventive removal of all large or substernal goiters.

Late arterial aneurysm proximal to corrected post-traumatic arteriovenous fistula.

A 60 year-old man presented with an extensive iliofemoral aneurysm discovered 11 years after the closure of a long-standing (28 years) post-traumatic arteriovenous fistula (AVF). Treatment by exclusion and bypass was successful. Fifteen other such cases have been reported in the literature in the last 15 years. While cardiomegaly is reversible once the AVF has been closed, arteriomegaly continues to increase or may begin only after closure. The mechanism for this phenomenon is debated. All arterial dilatations discovered during or after closure of AVF must be treated because of the risk of rupture. Prevention implies early treatment of all AVF. If the AVF is long-standing, the caliber of the artery proximal to the site of repair must be carefully measured and all dilated segments replaced. The patient should be warned of the possibility of late arteriomegaly proximal to the site of closure.

[The risk of aneurysm. Another reason to treat traumatic arteriovenous fistulas surgically]. / Le risque anévrysmal. Autre raison d'opérer les fistules artério-veineuses traumatiques.

A new case of late arterial aneurysm proximal to a corrected post-traumatic arterio-venous fistula is compared to 15 similar observations published in the last 20 years. The meantime between the vascular injury and the disclosure of the fistula was 20 years. The arteriomegaly was discovered only after the fistula was closed in 11 of the 16 cases including our case. These arterial dilatation extended primarily or secondarily from the aorta to the fistula area. Late arteriomegaly is a second reason for operating the arterio-venous fistulas. If the fistula is longstanding, the caliber of the proximal artery must be checked during and after the operation. Risks of embolism and rupture being important, all arterial dilatations must be managed by vascular replacement procedures. If the iliac artery seems uninvolved, the patient must be warned that dilatation may occur in the arterial segment proximal to the upper anastomosis. A long term survey is always mandatory.