Layered double hydroxide and zirconium phosphate as ion exchangers for the removal of 'black crusts' from the surface of ancient monuments.

The chloride form of MgAl layered double hydroxide (hereafter MgAlCl) as an anion exchanger and the semisodic form of α-zirconium phosphate (hereafter ZrPNaH) as a cation exchanger are proposed as new cleaning agents for the removal of gypsum from ancient monuments. The ability of these exchangers to capture the calcium and sulphate ions of the gypsum powder was first investigated separately and then as a coupled system. MgAlCl/gypsum, ZrPNaH/gypsum and MgAlCl/ZrPNaH/gypsum mixtures were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and dispersive X-ray spectroscopy (EDX). ZrPNaH in the form of a wet paste exhibited a rapid uptake of calcium from gypsum powder via Na+ and H+/Ca2+ cation exchange. Gypsum powder was also successfully dissolved by a wet paste of MgAlCl by exploiting the Cl-/SO42- anion exchange reaction. However, the dehydration of the paste favoured the reprecipitation of a secondary gypsum that was characterized by lower crystallinity and smaller particle size than the pristine gypsum. The combination of wet MgAlCl and ZrPNaH showed a synergic effect on the dissolution of gypsum and partially prevented the reprecipitation of gypsum in the dry paste. Finally, a preliminary test of the removal of gypsum crust grown on a sandstone sample was performed.

Temperature-dependent dynamics of water confined in nafion membranes.

We performed a neutron scattering study to investigate the dynamical behavior of water absorbed in Nafion at low hydration level as a function of temperature in the range 200-300 K. To single out the spectral contribution of the confined water, the measurements were done on samples hydrated with both H(2)O and D(2)O. Due to the strong incoherent scattering cross section of hydrogen atoms with respect to deuterium, in the difference spectra, the contribution from the Nafion membrane is subtracted out and the signal originates essentially from protons in the liquid phase. The main quantities we extracted as a function of the momentum transfer are the elastic incoherent structure factor (EISF) and the line width of the quasielastic component. Their trend suggests that the motion of hydrogen atoms can be schematized as a random jumping inside a confining region, which can be related to the boundaries of the space where water molecules move in the cluster they form around the sulfonic acid site. Through the calculated EISF, we obtained information on the size of such a region, which increases up to 260 K and then attains a constant value. Above this temperature, the number of water protons that are dynamically activated in the accessible time window increases with a faster rate. The jump diffusion dynamics is characterized by a typical jumping time which is stable at 5.3 ps up to approximately 260 K and then gradually decreases. The ensemble of the findings indicates that, within the limits of the energy resolution of the present experiment, water absorbed in the Nafion membrane undergoes a dynamical transition at around 260 K. We discuss the possible relationship of this dynamical onset with the behavior of the electrical conductivity of the membrane as a function of the temperature.

[Evaluation of the peak bone mass by quantitative heel ultrasound in young women of the centre of Italy]. / Valutazione ultrasonometrica calcaneare del picco di massa ossea in giovani donne dell'Italia centrale.

OBJECTIVE: To measure the reference young adult mean values in healthy women of the centre of Italy by Quantitative heel UltraSound (QUS). METHODS: The study group was composed by 70 caucasian women: mean age was 25.4 years (Standard Deviation 4.7), mean weight was 58 Kg (SD 8.2), mean height was 166 cm (SD 5.8), mean BMI was 20.9 kg/m 2 (SD 2.5). Every subject was evaluated firstly with an original questionnaire to discover risk factors (like for example steroids consumption, recent fractures of the lower limb), then was measured by quantitative heel ultrasonometry Hologic Sahara. RESULTS: Mean extimated Bone Mineral Density (BMD) 0.588 g/cm 2 (SD 0.124) mean Quantitative Ultrasound Index (QUI) 105.0 (SD 19.6), mean Speed of Sound (SOS) 1564.2 m/s (SD 31.4), mean Broadband Ultrasound Attenuation (BUA) 84.8 dB/MHz (SD 17.4). No significant correlation was found between QUS parameters and anthropometric data. A correlation was found between every QUS parameters. No significant differences were found about QUI and extimated BMD, between our results and Hologic normative data for European women. CONCLUSIONS: It is very important to develop specific reference values for any measurement device and site of skeleton especially in the age of reaching the peak bone mass because the T score is then measured referring to these data. Usually the normative data are supplied by manufacturer and are based on large multicentric study. In our opinion it could be helpful to verify if these data are compatible with the population examined in every region.

[Laparoscopic cholecystectomy: analysis of first 203 cases]. / Colecistectomia per via laparoscopica: analisi dei primi 203 casi.

Laparoscopic cholecystectomy is a valid alternative to open cholecystectomy. The Authors present their experience in the management of 208 consecutive patients. The low incidence of complications, the short hospital stay as well as earlier return to work, and lower medical expenses are the advantages of laparoscopic surgery. The latter is, therefore, more suitable for the treatment of benign gallbladder diseases.

The responses of dissociative patients on the thematic apperception test.

This study compared the responses of dissociative inpatients and general inpatient psychiatric controls on the Thematic Apperception Test (TAT; Murray, 1943). We found the stories of dissociative participants to be characterized by a greater interpersonal distance and more trauma and dissociation responses than those of the controls. No significant differences were found regarding total number of emotional references, although references to positive emotions were almost nonexistent for the dissociative group. A post hoc analysis of the data found the testing behaviors of dissociative participants to be characterized by switching, trance states, intrainterview amnesias, and affectively loaded card rejections. Questions were raised regarding the relevancy of the findings to clinical practice and how they might explain some of the controversies surrounding the diagnosis of dissociative identity disorder (DID).

Multiple complex coronary plaques in patients with acute myocardial infarction.

BACKGROUND: Acute myocardial infarction is believed to be caused by rupture of an unstable coronary-artery plaque that appears as a single lesion on angiography. However, plaque instability might be caused by pathophysiologic processes, such as inflammation, that exert adverse effects throughout the coronary vasculature and that therefore result in multiple unstable lesions. METHODS: To document the presence of multiple unstable plaques in patients with acute myocardial infarction and determine their influence on outcome, we analyzed angiograms from 253 patients for complex coronary plaques characterized by thrombus, ulceration, plaque irregularity, and impaired flow. RESULTS: Single complex coronary plaques were identified in 153 patients (60.5 percent) and multiple complex plaques in the other 100 patients (39.5 percent). As compared with patients with single complex plaques, those with multiple complex plaques were less likely to undergo primary angioplasty (86.0 percent vs. 94.8 percent, P = 0.03) and more commonly required urgent bypass surgery (27.0 percent vs. 5.2 percent, P < or = 0.001). During the year after myocardial infarction, the presence of multiple complex plaques was associated with an increased incidence of recurrent acute coronary syndromes (19.0 percent vs. 2.6 percent, P < or = 0.001); repeated angioplasty (32.0 percent vs. 12.4 percent, P < or = 0.001), particularly of non-infarct-related lesions (17.0 percent vs. 4.6 percent, P < or = 0.001); and coronary-artery bypass graft surgery (35.0 percent vs. 11.1 percent, P < or = 0.001). CONCLUSIONS: Patients with acute myocardial infarction may harbor multiple complex coronary plaques that are associated with adverse clinical outcomes. Plaque instability may be due to a widespread process throughout the coronary vessels, which may have implications for the management of acute ischemic heart disease.

Increased expression of glomerular AT1 receptors in rats with myocardial infarction.

Rats with congestive heart failure demonstrate striking intrarenal vasoconstriction that contributes to reduced renal excretory function. We previously demonstrated that inhibition of angiotensin action reverses intrarenal vasoconstriction in rats 4-6 wk after coronary artery ligation. In the present study we tested the hypothesis that abnormalities in the expression and regulation of glomerular angiotensin receptors contribute to the intrarenal vasoconstriction. Because glomerular angiotensin type 1 (AT1) receptors normally downregulate in response to high local ANG II concentrations, we anticipated that glomerular AT1-receptor expression would be reduced in rats after myocardial infarction (MI). To our surprise, the density of glomerular AT1 receptors was nearly double (97% increase, P < 0.002) that of controls, indicating an acquired abnormality in angiotensin receptor regulation. This was specific for renal glomeruli, because the density of angiotensin receptors on renal vasculature was decreased in rats after MI compared with normal controls. Glomerular AT1-receptor expression was downregulated by an acute pharmacological infusion of ANG II and upregulated by acute angiotensin-converting enzyme inhibition to a similar extent in MI and control rats. Renal cortical mRNA expression showed an increase in the renin mRNA-to-actin ratio and angiotensinogen-to-actin ratio, indicating stimulation of the intrarenal angiotensin system in rats after MI. The data indicate a specific dysregulation of AT1 receptors in glomeruli but not blood vessels after MI.

Effect of reperfusion on biventricular function and survival after right ventricular infarction.

BACKGROUND: Although the salutary effects of reperfusion in patients with left ventricular infarction are well documented, the benefits in patients with acute right ventricular infarction are less clear. METHODS: To determine whether primary angioplasty improves right ventricular function and the clinical outcome in patients with right ventricular infarction, we performed echocardiographic studies before and after angioplasty in 53 patients with acute right ventricular infarction. RESULTS: Complete reperfusion, defined as normal flow in the right main coronary artery and its major right ventricular branches, was achieved in 41 patients (77 percent), leading to prompt and striking recovery of right ventricular function (mean [+/-SE] score for free-wall motion, 3.0+/-0.1 at base line and 1.4+/-0.1 at three days; P<0.001). Twelve patients (23 percent) had unsuccessful reperfusion, defined as the failure to restore right ventricular branch flow, with or without patency of the right main coronary artery. Unsuccessful reperfusion was associated with lack of recovery of right ventricular function (score for free-wall motion, 3.2+/-0.2 at base line and 3.0+/-0.9 at three days; P= 0.55), as well as persistent hypotension and low cardiac output (in 83 percent of the patients, vs. 12 percent of those with successful reperfusion; P=0.002) and a high mortality rate (58 percent, vs. 2 percent for those with successful reperfusion; P=0.001). CONCLUSIONS: In patients with right ventricular infarction, complete reperfusion of the right coronary artery by angioplasty results in the dramatic recovery of right ventricular performance and an excellent clinical outcome. In contrast, unsuccessful reperfusion is associated with impaired recovery of right ventricular function, persistent hemodynamic compromise, and a high mortality rate.

Improvement in sensitivity of enzyme-linked immunosorbent assay for tumour necrosis factor.

Various protocols were used in the development of enzyme-linked immunosorbent assays (ELISA) to improve the sensitivity and range of detection of human tumour necrosis factor-alpha (TNF-alpha). ELISA can provide a specific, sensitive and rapid method for detection of TNF-alpha in patient's sera, and it is important that the assay used should be sufficiently sensitive to detect low levels of TNF-alpha. The double sandwich ELISA proved to be the most sensitive, detecting less than 0.080 ng/mL TNF. Of eight different protocols, one assay using a purified monoclonal antibody to human TNF-alpha and rabbit polyclonal anti-TNF-alpha antibody had the greatest sensitivity and range of detection. The study illustrates methods for the development of sensitive immunoassays which may have applications in many assay systems.

Rapid bedside coronary angiography with a portable fluoroscopic imaging system.

The ability to perform coronary angiography rapidly at the bedside has multiple potential applications. This study was designed to determine whether a novel portable angiographic system (OEC Medical Systems, series 9600, Salt Lake City, Utah) is capable of producing high-quality angiograms. In 29 patients (70 vessels) undergoing elective catheterization in a conventional fixed laboratory (Siemens HICOR, Erlangen, Germany), we compared images obtained with the portable system to those from conventional fixed system. The portable system was 100% accurate in detecting both insignificant narrowing as well as significant stenoses (> 50% narrowing). There was complete concordance between systems for lesion location, TIMI flow, and collaterals. Thirty-two stenoses were analyzed in detail. Both quantitative and qualitative percent stenosis demonstrated similar value for lesion severity with both systems (R = 0.95, Kappa = 0.77, P < 0.001, respectively). Accuracy of lesion morphology by the portable system was similar to the fixed system (calcification 80%, eccentricity 92%). These findings demonstrate that a portable imaging system can produce high-quality coronary angiograms.