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This paper presents and discusses the measurement of permeability of Neapolitan Yellow Tuff (NYT) samples obtained in the framework of a study concerning the phenomenon of bradyseism, i.e. the slow vertical movement of soil, in the Campi Flegrei caldera (Campania—Italy). Measurements have been performed under isothermal, non-isothermal and transient non-isothermal conditions using a specifically designed apparatus. Results of measurements of porosity of different samples are also reported. Experimental results in isothermal conditions show that the volume flux through the samples changes linearly with applied pressure. The values of permeability obtained turn out to be independent of the temperature and pressure gradients applied to the samples. This result is consistent with the fact that the permeability is a characteristic of the porous medium, and as such is not affected by temperature and pressure variation, at least in the range examined. The permeability values measured in our laboratories agree quite well with the ones measured in situ by the Agenzia Generale Italiana Petroli (AGIP) during a geothermal exploration of the Campi Flegrei area in 1980. An interesting, still unexplained phenomenon has been detected during transient phases when both pressure and temperature gradients were applied to the samples. The phenomenon consists in an enhancement of volume flux due to heat flux in the transient phase. The extra volume-flux disappears once the steady temperature gradient is reached.

In this paper, the tuning mechanism for a two-dimensional (2-D) guided-wave photonic-crystal (PhC) filter obtained by varying the angle-of-incidence in the waveguide plane is demonstrated. Modeling and design of the filter have been carried out by using the Bloch-Floquet formalism. The device shows a resonance wavelength at 1550 nm for the p=30 order at normal incidence. The free spectral range (FSR) is about 38 nm and can be spanned with an in-plane angle of incidence /spl theta/ ranging from 0/spl deg/ to 14/spl deg/. The full width at half maximum (FWHM) is in the range 0.14-0.18 nm. The filter performance is suitable for 50-GHz dense-wavelength-division-multiplexing (DWDM) systems and shows that variable oblique incidence can be exploited as a tuning mechanism.

We have employed a simple Galerkin-approximation scheme to calculate nonequilibrium temperature and concentration fluctuations in a binary fluid subjected to a temperature gradient with realistic boundary conditions. When a fluid mixture is driven outside thermal equilibrium, there are two instability mechanisms, namely a Rayleigh (stationary) and a Hopf (oscillatory) instability, causing long-ranged fluctuations. The competition of these two mechanisms causes the structure factor associated with the temperature fluctuations to exhibit two maxima as a function of the wave number q of the fluctuations, in particular, close to the convective instability. In the presence of thermally conducting but impermeable walls the intensity of the temperature fluctuations vanishes as q goes to zero, while the intensity of the concentration fluctuations remains finite in the limit of vanishing q. Finally, we propose a simpler small-Lewis-number approximation scheme, which is useful to represent nonequilibrium concentration fluctuations for mixtures with positive separation ratio, even close to (but below) the convective instability.

A finite difference method has been developed to simulate water flow in a 2D porous medium with boundary conditions specified in terms of pressure and temperature. The method computes steady-state solutions for temperature, pressure and fluid velocities. With an appropriate choice for boundary conditions it is possible to simulate the behaviour of a geothermal system with an incremental pressure and/or temperature applied to a finite part of the base. Pressure and temperature changes produce a change in the fluid flow regime leading to different final temperatures, pressures and fluid velocities (steady state). The method is particularly suitable for simulating the coupled mechanical and thermalfluid-dynamical effects at calderas, when increases in pressure and heat flow from a magma chamber perturb the conditions of the uppermost aquifer system. Several tests performed with realistic values for the parameters of the porous medium show that increases of pressure at the base are efficiently propagated in the upper medium by water flow, so that the effective centre of overpressure is shifted to considerably shallower levels. This effect can strongly modify the shape of ground deformations at calderas, and strongly amplify the peak values. The proposed method has been applied to the explanation of the very peculiar ground deformation observed at Campi Flegrei during 1982–1984, which showed very high uplifts (1.8 m) and a strong concentration in a small area (3×3 km 2 ). An integrated mechanical–thermalfluid-dynamical model for this caldera is proposed, which could be generalised to other areas.

Mechanical and thermal-fluid-dynamical contributions to unrest phenomena at active calderas are quantitatively evaluated, and a mixed mechanical-thermal-fluid-dynamical model is developed, to explain the unrest phenomena at Campi Flegrei caldera. Mechanical modelling involves the use of analytical and finite element formulations. Thermal-fluid-dynamical effects are considered in the framework of a one-dimensional approximation, solved by an analytical method. The results shed new light about the coupled effect of mechanically and thermally induced perturbations and variations in the geothermal fluid circulation regime. Unrest episodes at Campi Flegrei are interpreted in terms of the joint effect of a first, essentially mechanical, phase due to overpressure in a magma chamber and to a progressive amplification and final decay due to the circulating water. The elastic response of the rocks to the migrating front of overpressure is shown to be strongly conditioned by the caldera structure, which produces a concentration of strain in the inner part, and a stress concentration, causing the local seismicity, around the caldera borders. Thermal-fluid-dynamical effects are also shown to have important implications on the evolution of the volcanic system towards critical phenomena, which must be considered for a meaningful evaluation of volcanic hazard.

A study on the coverage of influenza vaccination among elderly people was carried out. Fity-six per cent of those interviewed had been vaccinated (weighted coverage 50%), compared with the target of 75%, but higher rates were reported in those older than 74 years and those with chronic diseases.

We develop a model for describing water flow in a porous medium under the effect of thermal and pressure gradients. The model simulates geothermal systems in calderas. Given the boundary conditions and the fluid-dynamical properties of the medium, the model allows computation, in fluid-dynamical stationary states, of parameters characterizing the flow, such as flow velocity and temperature and pressure distributions at depth. The model is applied to investigate the effects of the local geothermal system on the unrest episodes at Campi Flegrei caldera. Using experimentally determined fluid-dynamical parameters for the caldera rocks, we show that changes of water flow in shallow aquifers under the effect of pressure and/or temperature variations within the geothermal system can be very important in the genesis and evolution of unrest crises. In particular, they can strongly amplify the effect of pressure increase in the magma chamber on ground uplift. They can also explain the timescales of evolution of ground movements in terms of transit times of the water front and of the connected temperature fronts due to advective transport. On such grounds an integrated mechanic-thermal fluid-dynamical model was built, allowing us to give a semiquantitative, global explanation to the genesis and evolution of unrest phenomena. Results obtained here can be generalized to other similar calderas.

Summary This study evaluated the immunogenic and protective effects of plasma-derived and DNA recombinant anti-hepatitis B virus vaccines administered to infants at various ages and with different vaccination schedules: 3 monthly doses in the first 3 months of life, 3 doses (at 3, 5 and 11 months) or 2 doses (at 1 and 3 months) or 2 doses (at 3 and 5 months). Anti-HBs (hepatitis B surface) and anti-HBc (hepatitis B core) markers were investigated twice: one month and ten years after vaccination in 261 children immunized with plasma-derived vaccine, and one month and five years after vaccination in 449 children immunized with DNA recombinant vaccine. In all groups, the appearance of anti-HBs protective levels one month after vaccination and their persistence in the following years were found in a larger number of subjects when the vaccine doses had been administered after the third month of life rather than in the first three months. Moreover, our results show that the reappearance of surface antibodies a week after the booster, in vaccinated children who became anti-HBs − in the years following vaccination, occurred in a larger number of subjects when the primary vaccination with 3 doses had been performed in the first quarter or with 2 or 3 doses in the second quarter. In contrast, protective levels of anti-HBs were found in a small number of children belonging to the group vaccinated with 2 doses in the first three months, and among them the majority seroconverted only one month after the booster. Anti-HBc was found 10 years after vaccination in only one child immunized with 2 doses of plasma-derived vaccine, and 5 years after vaccination in two children immunized with 2 doses of DNA recombinant vaccine. All these children were found to lose anti-HBs, and none of them had signs of disease or became a carrier. Based on these results, the disappearance, in some children, of protective levels of anti-HBs in the years following vaccination does not mean the loss of anti-HBV protection. In fact, the trial showed that they reacted immediately to booster stimulation, demonstrating a solid immunologic memory. Therefore, there may be no reason for giving booster injections when the vaccination of infants is carried out correctly.

Isothermal matter transport due to gradients of chemical potential was studied with different electrolytic solutions and an hydrophobic porous membrane. Countercurrent fluxes of solute and solution in bulk were observed in each case. Impeding volume flux, transmembrane pressures are developed proportional to concentration gradients and much smaller than Van't Hoff osmotic pressures, indicating a poor membrane reflectivity. Starting from our experimental observations we propose a simple model of an idealized membrane, whose pores interact only hydrodynamically with bulk flow, while countercurrent diffusion of solvent and solute occurs in each channel along the respective gradients of chemical potential. This model is shown to work in every respect just as real-life membranes.

Our research aimed to evaluate the risk of haemorrhage following oral surgical operations, in patients who were undergoing an anticoagulant therapy, and to test the usefulness of the autologous platelet gel in order to control haemostasis.A total of 208 patients (84 males/124 females) undergoing an anticoagulant therapy and submitted to oral surgery, were divided at random into 4 groups (A, B, C, D) consisting of 52 patients each, using as criterion of differentiation the kind of treatment we adopted in order to get haemostasis. The patients belonging to the first 3 groups (A, B, C), underwent a surgical operation without discontinuing the dicumarol therapy. In order to get haemostasis, we used: platelet-rich plasma (PRP) and suture, in group A; PRP, haemostatic sponges and suture, in group B; haemostatic sponges, suture and compression by means of gauzes soaked in tranexamic acid in group C. Group D, instead, consisted of patients who underwent a surgical operation, before which the dicumarol therapy had been suspended and replaced by heparincalcium.Patients belonging to the groups A and B showed a very good haemostasis like the patients of group D (control group). As the coumarin therapy didn't need to be discontinued some days before the surgical operation, so the days of hospital stay were reduced and there wasn't the risk of thromboembolism. As to group C (19 males), 6 patients (i.e. 11.5%) showed a good haemostasis, both at once and in the long term, so that they could be discharged on day 2 after surgery.The results obtained during our research, highly encourage using PRP regularly when carrying out surgical treatments on patients who are undergoing a coumarin therapy.

The kinship between liquids and solids, advocated by the similarity of the respective densities, did not lead, until now, to a theory of transport processes in liquids in analogy to the phonon theory of solids. The ubiquitous presence of scattering centers due to the disordered structure of fluids makes a quantitative appraisal of energy and momentum exchange in the course of phonon-particle interactions pivotal for such an approach. The new physical concepts of radiant vector and of thermal radiation force provide the appropriate fundamentals for a quantitative treatment. The experimental foundations of the proposed theory reside in a clear-cut assessment and in the appropriate measurement of thermal radiation forces in the appropriate material system. For reasons discussed here such an unambiguous result may be only obtained in conditions of reduced gravity.

Burning mouth syndrome (BMS) is a chronic painful syndrome in clinically normal oral mucosa. There are many local, systemic and/or psychogenic pathological conditions that may clinically appear as burning and painful sensation of the oral mucosa. There are essential or idiopathic BMS and organic or secondary BMS. A diagnostic and therapeutic protocol is proposed by the authors evaluating, the effectiveness of the estroprogestinic replacement therapy in post-menopausal women suffering from idiopathic BMS.A total of 28 patients suffering from persistent burning and painful oral sensation underwent to careful clinical and laboratory examination in order to distinguish primary forms from secondary ones. Patients suffering from primary BMS underwent to incisional biopsy for the research of estrogens receptors.Only 8 out of the 28 studied patients (28.5%) were negative to the clinical oral and laboratory examinations listed in our protocol and they were diagnosed for primary BMS. All of them were females.The use of a valid diagnostic and therapeutic protocol allows a better management of patients suffering from oral pain and a reduction if not a disappearance of the burning symptomatology in most of them. In post-menopausal patients suffering from idiopathic BMS good results may be obtained by an estroprogestinic replacement therapy.

Production of high- performance and low-cost new devices to be used in space applications is strongly required due to the remarkable development of innovative technologies in the last few years. Guided-wave optoelectronics technologies, including integrated optics, acousto-optics and electro-optics can provide some significant benefits to the space applications. In particular, they can overcome the intrinsic limits of the conventional technologies improving also the cost/performance figures, and enabling new services. Earth observation, telecommunications, radar surveillance and navigation control are the main space areas where guided-wave devices can contribute significantly. In this paper, after some general considerations on the potential of optoelectronics for space, on the use of acousto-optic guided-wave devices, a brief description of the acousto-optic interaction is given. Some functional devices reported in literature having significant potential impact in space applications are described with the aim of highlighting the main features of the acousto-optic technology. The performance limits of guided-wave devices for space applications are also shortly discussed.

The design of two dimensional guided wave photonic band gap filters based on Fabry-Perot microcavities is presented. Both single and multiple cavities structures have been simulated by applying the Bloch-Floquet modelling approach. Performances of the filters are suitable for DWDM telecommunication systems.

Very compact and low-cost rotation sensors are strongly required for any moving systems in several applications. Integrated optical angular velocity sensors seem to be very promising in terms of low cost, compactness, light weight and high-performance. In the paper a new integrated optical angular velocity sensor having a passive resonant configuration is proposed. Preliminary results are really encouraging and demonstrate the possibility of using the sensor in gyro systems for satellite applications.

A very compact narrow‐band 2D photonic band gap filter has been designed under oblique incidence condition. Q‐factors of the order of 103, FSR of 53 nm and FWHM equal to 1.3 nm have been calculated.

The space experiment TRAMP (Thermal Radiation Aspects of Migrating Particles) flown in 1999 onboard the mission Foton 12 sponsored by the European Space Agency (ESA), was conceived to reveal and measure a new kind of forces, named Thermal Radiation Forces (TRF). The experiment was dramatically disturbed by the occurrence of undesired convective motions due to the rotation of the spacecraft. Apart from that, corrosion occurred in some parts of the flight apparatus, resulting in the presence of gas bubbles inside the experimental liquid, completely compromising the results. Consequently, the experiment did not allow to reveal and/or to measure TRF, but it turned out to be useful in another way, as a very sensitive accelerometer, since the accelerations deduced from velocity measurements concurred with those measured by the Quasi-Steady Acceleration Measurement (QSAM) system.

[1] The Campi Flegrei caldera is characterized by well known episodes of fast uplift, called “bradyseism,” the last of which produced ∼1.8 m of maximum vertical displacement in the period 1982–1984. Less known is a particular aspect of Campi Flegrei unrests, detected only in the last 20 years, namely, the occurrence of “miniuplift” episodes, characterized by relatively small positive vertical displacements (in the range 0.03–0.11 m). Miniuplift episodes occurred in 1989, 1994, and 2000 and, probably, one or two times in the period 1972–1982. These small ground uplifts were also accompanied by moderate seismicity. Each of them was followed by a short phase of relatively quick subsidence, after which the previous rate of subsidence of the period was resumed. An order-of-magnitude analysis of the forces, energy, and power that can cause the onset and determine the evolution of these events is derived on the basis of a thermal-fluid-dynamical approach. It allows the quantitative correlation of the power input from the energy source with the rate of energy dissipation in the geologic system during the miniuplifts. In order to assess the likelihood of our fluid-dynamical model for these episodes, theoretical ground displacements have been computed. These displacements result from the changes in pressure as a function of depth predicted by the fluid-dynamical model for reasonable perturbations of the geothermal system, described as changes of the Peclet number. Theoretical results agree extremely well with the observed amounts of the miniuplifts.

The aim of the study was to assess the role of non-operative treatment in haemodynamically stable patients with liver trauma. Over the period from 1996 to July 2000, out of a total of 2,048 patients with abdominal trauma, 124 open and 1,924 closed, we observed 77 hepatic lesions, consisting of 55 closed traumas and 22 penetrating traumas. Non-operative treatment was implemented in 18 patients (32.7%) with closed liver traumas. In addition to serial clinical examinations of the abdomen, the patients receiving non-operative treatment were submitted to thorough haemodynamic monitoring and complete blood counts in the intensive care unit. After an abdominal CT scan at entry, patients were submitted to abdominal ultrasonography 6, 12 and 24 hours after admission. Only two patients required transfusions, one presenting a pelvic fracture and the other a triple fracture of the femur, tibia and fibula. There was no mortality. A biloma was present in one case, successfully treated by means of a US-guided drainage puncture. It is patients with major cranial traumas that pose most problems for conservative treatment. Fifty percent of non-therapeutic laparotomies in our series were performed in patients with severe cranial traumas. It is precisely in these patients that an improvement in diagnostic capability is most desirable.

A significant percentage of dialysed patients have inadequate protein intake. One strategy for treating the protein malnutrition in peritoneal dialysis patients is to replace glucose in the dialysis solution by amino acids. A new peritoneal dialysis solution containing 1.1% amino acids in a formulation optimized for renal patients and with a lactate concentration of 40 mmol/l has been evaluated. Fifteen CAPD patients completed a non-randomized prospective 3-month study. Each patient received 2 litres of the optimised 1.1% amino acid solution for the second exchange of the day with a dwell time of 5-6 h. Indicators of efficacy were serum albumin and transferrin. After 3 months of intraperitoneal amino acids, serum albumin levels significantly increased from 32.7 +/- 2.3 to 35.1 +/- 2.2 g/l (mean +/- SD; P0.01). This occurred in parallel with a significant increase in transferrin levels from 2.21 +/- 0.26 to 2.39 +/- 0.27 g/l (P0.05). As expected, urea rose from 23.7 +/- 6.8 to 29.9 +/- 9.4 mmol/l. Interestingly bicarbonate did not change (25.5 +/- 4.2 versus 25.2 +/- 3.3 mmol/l). These results suggest that the optimized formulation is effective in improving nutritional parameters in CAPD patients while avoiding unwanted side-effects such as acidosis.

We continue the study of liquids considered as composed by two interacting subsystems: a population of particles, weakly bound to the sites of a disordered lattice, and a ``gas'' of phonons. The interactions among the material particles and the wave packets are mediated by ``thermal radiation forces,'' a special class of inertial effects. When the liquid system is a solution, the application of a temperature or a concentration gradient breaks the symmetry of one of the two subsystems, producing an excess of phonon-solute collisions and performing work on the particles, at the expense of the thermal energy of the wave packets. The heats of transport of thermal diffusion, isothermal diffusion, and Soret equilibrium may be statistically calculated from the energy balance of these collisions. The expressions arrived at by this approach are coincident with the ones obtained by nonequilibrium thermodynamics, although for our derivation Onsager reciprocal relations are not required. It is also argued that, within the frame of the phonon theory, transport processes in liquids may be treated in general by means of the classical Boltzmann transport equation, applied to phonon-particle interactions rather than to particle-particle collisions.

The purpose of this investigation was to evaluate lipopolysaccharide (LPS)-stimulated monocyte secretory responses longitudinally in patients with generalized severe chronic adult periodontitis (periodontitis-susceptible) and controls with gingivitis (periodontitis-resistant). In addition, the expression of constitutive (Leu-M3) and LPS-inducible (Mo3e) antigens on monocytes isolated from these two groups was examined. Monocyte secretory function was assessed longitudinally; the effect of periodontal therapy in the susceptible patients was examined by comparing monocyte function before and after their treatment. Peripheral blood monocytes were isolated by counterflow centrifugal elutriation and treated with control medium or media containing 1 μg/ml of Salmonella typhimurium LPS or Prevotella intermedia LPS with or without human recombinant interferon (IFN)-γ pretreatment. Prostaglandin E 2 , F 2α and thromboxane B 2 were quantified in culture samples by gas chromatography-mass spectrometry (GC-MS) and interleukin-1β was quantified by enzyme-linked immunosorbent assay. Leu-M3 and Mo3e antigen expression was assessed by FACScan. Three major findings were made. First, LPS-stimulated IL-1 β release by monocytes from susceptible patients was depressed relative to that in resistant patients at the initial donation. After periodontal therapy, there was virtually identical IL-1β release in LPS-stimulated cultures from both groups. However, in susceptible patients IL-β release was diminished after periodontal therapy in cultures pretreated with IFN-γ. Second, there was a significant drift in monocyte secretion of prostaglandin E 2 in samples from the resistant patients between the first two donations and the third donation. PGE 2 release did not differ between groups at the initial donation, although there was a depression in PGE 2 release in the susceptible group at the final donation when IFN-γ was followed by S. typhimurium LPS. Finally, P. intermedia LPS relative to S. typhimurium LPS selectively potentiated PGE 2 release in the samples from the susceptible group after IFN-γ pretreatment. This effect was observed for all donations. These data suggest that IFN-γ priming results in monocyte differentiation processes that are not the same in both groups. Therefore, the local determinants of macrophage activation require further evaluation. These differences between resistant and susceptible patients may be most evident in inflamed gingival tissue where macrophages have been exposed to the inflammatory milieu.

CD14 has been reported to be the lipopolysaccharide (LPS)-LPS binding protein receptor. The effects of interferon-gamma (IFN-gamma) on CD14 expression have not been clearly established. The purpose of this investigation was to examine the effects of IFN-gamma alone and IFN-gamma followed by bacterial LPS on CD14 expression. Human peripheral blood monocytes were isolated by counterflow centrifugal elutriation (CCE). Monocytes were cultured for 48 h with IFN-gamma alone or for 24 h with IFN-gamma followed by LPS for a second 24 h. IFN-gamma alone caused a down-regulation of CD14 expression, as assessed by flow cytometry, relative to CD14 expression in untreated monocytes. In addition, CD14 expression was even more significantly down-regulated after IFN-gamma pretreatment followed by either Prevotella intermedia or Salmonella typhimurium LPS. Likewise, the percentage of CD14+ monocytes decreased after IFN-gamma alone and even more dramatically after IFN-gamma treatment followed by either LPS. This study clearly demonstrated that IFN-gamma down-regulates CD14 expression and that LPS following IFN-gamma pretreatment potentiates this effect.

Reports in the literature have linked a low phosphatidylcholine content in continuous ambulatory peritoneal dialysis (CAPD) effluent to ultrafiltration loss. Clinical evidence suggests that adding phosphatidylcholine to the dialysis solution enhances ultrafiltration. A clinical study has been designed to clarify the effect of phosphatidylcholine on ultrafiltration in CAPD patients with normal ultrafiltration. A weekly measurement of the peritoneal equilibration test was conducted per patient in the hospital. A comparison between the control dialysis solution (three-week period) and the phosphatidylcholine premixed solution (three-week period) was performed on a total of 12 patients. This study shows that a phosphatidylcholine premixed dialysis solution significantly enhances ultrafiltration. Since ultrafiltration per osmotic driving force (mL/g glucose) is enhanced, the patient's glucose load per day is reduced to achieve equal ultrafiltration. In the presence of phosphatidylcholine, peritoneal permeability remained unchanged, as indicated by membrane transport characteristics. No side effects were observed.

In order to prevent exit-site infection, we studied a new Tenckhoff-derived catheter, named the "Malpighi catheter," capable of avoiding sinus tract formation. The outer cuff of this new device is 3.5 cm long and is deliberately positioned half-extruded; in fact, half of the cuff remains outside the skin exit-site. The implantation technique is identical to that of the standard two-cuff Tenckhoff catheter. We implanted eight Malpighi catheters in 5 CAPD and 3 IPD patients. The observation period was 146 patient-months (range 14-23, M +/- SD 18.2 +/- 3.3). We observed excellent adhesion between the outer cuff and surrounding tissue. Actually, by pulling the catheter the skin around the half-extruded cuff becomes cone-shaped, with the cone's apex tightly stuck to cuff and the sinus tract disappearing completely. Only one case of exit-site infection by Staphylococcus aureus and two cases of ulcer of the skin beneath the external part of the half-extruded cuff were observed. These complications were resolved completely. No catheter needed to be removed and there were no leakages. The histological study of the cuff showed a good infiltration of the dacron cuff by fibrous tissue. On the grounds of our preliminary experience, we believe that the absence of the sinus tract, the formation of an efficient mechanical and bacterial barrier and the reduction of exit-site infection incidence are all factors that encourage further research.

Laceration of the esophagus related to ingestion of tortilla corn chips has been described in the past. However, no cases of perforation of the esophagus are known to be associated with tortilla corn chip ingestion. We describe a case of previously undiagnosed achalasia in a patient who presented with an esophageal perforation after ingestion of tortilla corn chips.

In this study a simple rat model for evaluating the ultrafiltration by peritoneal dialysis solutions is described. Anaesthetised male Sprague-Dawley rats were injected intraperitoneally with dialysis solutions. Zero, 1, 3, or 6 h later, the dialysate volume was determined directly: the abdomen was carefully opened, the intraperitoneal liquid was withdrawn with a syringe and its volume was measured. Good recovery of dialysate, highly reproducible results, and the similarity between the ultrafiltration profiles in rats and published profiles in CAPD patients for control solutions, indicate that the model is valid. The model was then used to evaluate peritoneal dialysis solutions containing a mixture of glycerol and amino acids. Both osmotic agents are chemically compatible and these mixtures provide amino acids and carbohydrates in a single solution. For three mixtures, intraperitoneal dialysate volume were determined as a function of dwell time and the formulation with the desired ultrafiltration could be selected.

A total of 127 patients from 8 hospitals were randomized into 1 of 2 exit-site care regimes to evaluate their effect on rate of exit-site infection (ESI). Group 1 used povidone iodine and nonocclusive dressings changed 2 to 3 times weekly; Group 2 simply cleansed the exit site with nondisinfectant soap and water. Incidence, cause, duration, and treatment of ESI and peritonitis (P) were noted. Groups were analysed for age, sex, end-stage renal disease (ESRD), catheter, and systems. Total cumulative follow up time was 95.6 years. There was a significantly higher rate (p = 0.0183) of ESI in Group 2 (soap and water). The mean rate of ESI was 0.27 episodes/patient year for Group 1 versus 0.71 episodes/patient year for Group 2. Rates of P for the two groups were not significantly different (p greater than 0.50): 0.446 episodes/year for Group 1 versus 0.574 episodes/year for Group 2. S. aureus was responsible for 83% of ESI in Group 1 and 67% of ESI in Group 2. Protective dressing with a disinfectant is associated with significantly less ESI than minimum care. However, further research in exit-site care aimed specifically at reducing S. aureus infection is still required.

The parametric analysis of the electromagnetic properties of 2D guided wave photonic band gap structures is reported with the aim of providing a valid tool for the optimal design. The modelling approach is based on the Bloch-Floquet method. Different lattice configurations and geometrical parameters are considered. An optimum value for the ratio between the hole (or rod) radius and the lattice constant does exist and the calculation demonstrated that it is almost independent from the etching depth, only depending on the lattice type. The results are suitable for the design optimisation of photonic crystal reflectors to be used in integrated optical devices.

In choosing the surgical method of correction of radial clubhand, one must take into consideration the age of the patient, the anatomical, radiographic and pathological alterations, and lastly the function of the homolateral elbow. Angiographic studies of the malformation have proved of value in revealing the possible coexistence of a normal vascular bed with hypogenesis of the radius. The esthetic and functional results obtained with two different surgical techniques, and followed up over the years, are reported in a fifteen year old boy and an eight year old girl.