Total reflection X-ray fluorescence (TXRF) for direct analysis of aerosol particle samples.

Atmospheric aerosol particles have a great impact on the environment and on human health. Routine analysis of the particles usually involves only the mass determination. However, chemical composition and phases provide fundamental information about the particles' origins and can help to prevent health risks. For example, these particles may contain heavy metals such as Pb, Ni and Cd, which can adversely affect human health. In this work, filter samples were collected in Brescia, an industrial town located in Northern Italy. In order to identify the chemical composition and the phases of the atmospheric aerosols, the samples were analysed by means of total reflection X-ray fluorescence (TXRF) spectrometry with a laboratory instrument and X-ray microdiffraction at Synchrotron Daresbury Laboratories, Warrington (Cheshire, UK). The results are discussed and correlated to identify possible pollution sources. The novelty of this analytical approach is that filter samples for TXRF were analysed directly and did not require chemical pretreatment to leach elements from the aerosol particulates. The results of this study clearly show that TXRF is a powerful technique for the analysis of atmospheric aerosols on 'as-received' filters, thereby leaving samples intact and unaltered for possible subsequent analyses by other methods. In addition, the low detection limits for many elements (low ng/cm2) indicate that this method may hold promise in various application fields, such as nanotechnology.

Polymer-coated quartz crystal microbalance chemical sensor for heavy cations in water.

A flow type quartz crystal microbalance (QCM) (bio)chemical sensor was developed for the real time determination of heavy metal ions that is suitable for environmental monitoring. A new process has been developed which enables to obtain surface-modified gold electrodes with high heavy metal ions complexing ability. The sensing performances of the piezoelectric sensor used in a flow-through setup were investigated by monitoring the frequency variation induced by the presence of heavy metal ions, such as copper and lead, as model ions, in aqueous media. X-Ray Reflectivity (XRR) and Atomic Force Microscopy (AFM) were carried out to characterize the unmodified and modified gold surfaces.

Silencing of membrane-associated sialidase Neu3 diminishes apoptosis resistance and triggers megakaryocytic differentiation of chronic myeloid leukemic cells K562 through the increase of ganglioside GM3.

In chronic myeloid leukemia K562 cells, differentiation is also blocked because of low levels of ganglioside GM3, derived by the high expression of sialidase Neu3 active on GM3. In this article, we studied the effects of Neu3 silencing (40-70% and 63-93% decrease in protein content and activity, respectively) in these cells. The effects were as follows: (a) gangliosides GM3, GM1, and sialosylnorhexaosylceramide increased markedly; (b) cell growth and [(3)H]thymidine incorporation diminished relevantly; (c) as mRNA, cyclin D2, and Myc were much less expressed, whereas cyclin D1 was expressed more like its inhibitor p21; (d) as mRNA, pro-apoptotic proteins Bax and Bad increased with concurrent decrease and increase in the anti-apoptotic proteins Bcl-2 and Bcl-XL, respectively; (e) the apoptosis inducers etoposide and staurosporine were active on Neu3 silencing cells but not on mock cells; (f) as mRNA, the megakaryocytic markers CD10, CD44, CD41, and CD61 increased similar to the case of mock cells stimulated with PMA; (g) the signaling cascades mediated by PLC-beta2, PKC, RAF, ERK1/2, RSK90, and JNK were largely activated. The induction of a GM3-rich ganglioside pattern in K562 cells by treatment with brefeldin A elicited a phenotype similar to that of Neu3 silencing cells. In conclusion, upon Neu3 silencing, K562 cells show a decrease in proliferation, propensity to undergo apoptosis, and megakaryocytic differentiation.

Elastic and magnetic dynamics of nanomagnet-ordered arrays impulsively excited by subpicosecond laser pulses.

This Letter reports on the first observation of elastic and magnetic dynamics of ordered arrays of permalloy nanodots excited by low-intensity 120 fs light pulses. The first order of the diffraction pattern, generated by the probe beam in a pump-probe configuration, is used for time-resolved reflectivity and time-resolved magneto-optical Kerr effect measurements. The nonadiabatical absorption of the pump triggers an acoustic standing wave, detected by the reflected probe signal, with a frequency related to the array wave vector. Instead, the magneto-optical signal exhibits, on the nanosecond time scale, the signature of the heat-exchange diffusion processes. In addition, a clear oscillation of the magnetic signal, at a frequency close to the frequency of the acoustic wave, is unambiguously detected. Finally, the interplay between the elastic and magnetic dynamics is analyzed and interpreted.

Diagnostic and surgical management of patients with aneurysms of the thoracic aorta with various causes. Echocardiography and contrast enhanced computed tomography in prophylactic replacement of the ascending aorta.

Sixty eight patients with aneurysms of the thoracic aorta were studied. Forty one had aortic dissection, 24 had dilatation only, and three had transverse aortic rupture. Sixteen had Marfan's syndrome; 17 had hypertension; and in eight there were other causal factors. In 17 the cause of the aneurysm was unknown. Histological examination did not help to establish the cause of aneurysm. Echocardiography failed to detect dissection of the ascending aorta in four (21%) out of 19 cases studied. The mortality rate in the whole series was 26%. Early (operative and hospital) and late deaths occurred in 20% and 6% of patients respectively. The early mortality rate was 40% in the 24 emergency cases of dissection of the ascending aorta, 9% in patients operated on for dilatation of the ascending and transverse aorta without dissection, and 8% in patients with chronic dissection of the ascending aorta who had elective operation. Early and late mortality rates were no higher in patients with Marfan's disease than in any of the other groups. It is suggested that contrast enhanced computer tomography should be performed in all patients with pronounced aortic root dilatation and in patients with Marfan's disease with symptoms which suggest dissection, even if they have only slight aortic root dilatation. Preventive replacement of the ascending aorta should be considered in more patients to reduce the number of emergency operations, in which the mortality rate is high. There is no definite limit of aortic root dilatation above which preventive replacement of the ascending aorta should be routinely considered.

Pulmonary valve agenesis and supravalvular pulmonary stenosis. Report of a case and review of literature.

Pulmonary valve agenesis is a rare malformation, and is usually associated with a ventricular septal defect. Occasionally it may be associated also with right ventricular outflow obstruction. Children with this syndrome usually die early in infancy either of intractable heart failure or of severe respiratory distress. Rare instances of association with peripheral pulmonary stenoses have also been reported. We report the case of a three-year-old girl, asymptomatic except for failure to thrive, with pulmonary valve agenesis and coarctation of the pulmonary artery trunk.

[Emergencies in valvular surgery]. / Emergenze in chirurgia valvolare.

Ninety patients who underwent emergency cardiac valve surgery from January 1976 to December 1981 are reported. Patients were divided in two groups: those operated on native valves are included in group I; patients with prosthetic valves operated because of leakage or malfunction, in group II. In group I (57 patients) the aetiology was: rheumatic heart disease (34 cases); acute endocarditis (16 cases); sequelae of recent endocarditis (2 cases); luetic infection (1 case); sequelae of myocardial infarction (1 case); rupture of mitral chordae in mixomatous valve (3 cases). The emergency operation was prompted in 22 patients by cardiogenic shock, in 13 patients by intractable pulmonary edema, in 21 patients by low output syndrome, in one case by ventricular arrhythmias. In group II (33 cases) the causes of reoperation were: in 27 cases leakage (in 13 due to active endocarditis); in 6 cases variance of the occluder or thrombosis. The emergency originated in 12 cases from cardiogenic shock, in 11 cases from intractable pulmonary edema, in 9 cases from low output syndrome, in 1 case from ventricular arrhythmias. Twenty-six patients died perioperatively in group I and 17 in group II. Mean follow-up in group I was 26 months. Among 27 patients there were two deaths; 25 patients are alive and well (one has been reoperated again). Mean follow-up in group II was 21 months. Among the 15 patients observed there were 6 deaths (3 after re-reoperation); 9 patients are alive and well (one has been re-reoperated).' The Authors feel that surgery is mandatory in all such patients to ensure satisfying long term results, in spite of high perioperative mortality rate.

Aneurysms involving the aortic arch. Report on thirteen surgically treated patients.

Since the beginning of 1980, 13 patients with aneurysms of the aortic arch have been operated in our department. In 4 cases the aneurysm was limited to the aortic arch, while in 10 patients the ascending aorta was involved. In 7 patients an emergency procedure was required. Eleven patients were operated using deep hypothermia and circulatory arrest, in 2 right axillary and femoral artery cannulation with moderate hypothermia was used. In 5 patients a concomitant aortic insufficiency was corrected with a mechanical valve. Three patients died in the hospital. Transient cerebral dysfunctions occurred in 4 patients. Deep hypothermia and circulatory arrest provided a convenient method especially in older patients. Bleeding due to generalized coagulopathy and bleeding diathesis was one of the major problems. The methods adopted to avoid these complications are reported and discussed in detail.

An unusual case of congenital double coronary arteriovenous fistula.

A double coronary arteriovenous fistula (CAVF) was observed in a ten-year-old girl. A large, tortuous, and elongated right coronary artery, communicating with the right ventricle, was detected by two-dimensional echocardiography and confirmed at angiography. To our knowledge, no echocardiographic recognition of the origin and termination of a CAVF has been reported previously. Moreover, another fistula, connecting the left anterior descending coronary artery with the main pulmonary artery was also detected by selective left coronary arteriography. The anatomy of double CAVF was confirmed on surgery. A right CAVF draining into the right ventricle and a left CAVF draining into the main pulmonary artery seemed to be a very unusual combination.

[Massive pulmonary thromboembolism: medical or surgical treatment?]. / Tromboembolia polmonare massiva: trattamento medico o terapia chirurgica?

Anticoagulant-thrombolytic therapy and surgery, remain the topics of recent advances in the treatment of pulmonary embolism. The Authors have treated 3 patients with anticoagulant-thrombolytic therapy, and 14 patients with pulmonary embolectomy with cardiopulmonary bypass. By this experience, they suggest an indication for medical or surgical treatment for pulmonary embolism.