Spatially-resolved in-situ structural study of organic electronic devices with nanoscale resolution: the plasmonic photovoltaic case study.

A novel high spatial resolution synchrotron X-ray diffraction stratigraphy technique has been applied in-situ to an integrated plasmonic nanoparticle-based organic photovoltaic device. This original approach allows for the disclosure of structure-property relations linking large scale organic devices to length scales of local nano/hetero structures and interfaces between the different components.

[Surgical results in childhood primary comitant large-angle exotropia]. / Résultats chirurgicaux des exotropies primitives concomitantes à grand angle chez les enfants.

INTRODUCTION: The purpose of this study was to evaluate the surgical results in childhood primary comitant large-angle exotropia (>30Delta) after a single operation and to analyze the factors that could influence these results. PATIENTS AND METHODS: We carried out a retrospective study in all children presenting with comitant primitive exotropia at an angle greater than 30Delta, who were operated on in our department from January 1996 to December 2000 by various surgeons. One hundred thirty-eight (138) cases were reviewed. The children with a substantial A or V phenomenon, retraction syndromes, nystagmus, those presenting with a neurological disease and those who had had previous eye surgery were excluded. The postoperative results were classified in three categories: residual exotropia over 10Delta, good postoperative result (esotropia<10Delta, orthotropia or exotropia<10Delta), and consecutive esotropia over 10Delta. RESULTS: Ninety-seven children fulfilled the study criteria. Forty (41.2%) were boys and 57 (58.8%) girls. The average age at the time of surgery was 6.5 years (SD 3.1). Sixty-eight of 97 (70.1%) had intermittent exotropia. Twenty-six children (26.8%) underwent a bilateral recession of the lateral rectus, 67 (69.1%) a unilateral operation, recession of a lateral rectus/resection of a medial rectus, and four (4.1%) an operation on three horizontal muscles. Sixty-nine percent of the children operated on had a good postoperative result, according to criteria defined in our study, 1 year after surgery. DISCUSSION/CONCLUSION: Childhood primary comitant large-angle exotropia can be corrected with a single surgical procedure, unilateral or bilateral, with a success rate which, in our study, reached 69%.

Cataract surgery in children with uveitis.

PURPOSE: To report the technique and postoperative results of cataract surgery in children with uveitis. METHOD: Between 1988 and 1998, nine children (age range: 2.5-11 years) who developed secondary uveitic cataract and underwent cataract extraction were studied retrospectively. Seven children had juvenile rheumatoid arthritis and two had chronic anterior uveitis of unknown etiology. The surgical technique was lensectomy and wide anterior vitrectomy with limbal approach, lysis of anterior synechiae and in some cases, peripheral iridectomy. Postoperative aphakia was corrected with soft contact lenses in all patients. Follow-up ranged from 6 months to 6 years. RESULTS: Postoperatively, visual acuity in all patients improved and final visual acuity ranged from 20/70 to 20/25. Significant intraoperative complications did not occcur in any patient. One boy with juvenile rheumatoid arthritis developed cystoid macular edema 1 month postoperatively, which was successfully managed. He also developed hypertonia 1 year later, which was also successfully managed. Seven of the nine children had fewer and milder relapses of uveitis after surgery. CONCLUSION: Cataract surgery, using the lensectomy-vitrectomy technique in children with uveitis, is a safe technique with a relatively small percentage of postoperative complications and good functional results.

Effect of acute ventricular pressure changes on QRS duration.

The effect of acute changes in ventricular pressure is examined on the QRS duration to clarify the mechanism of ventricular pressure-related arrhythmogenesis. Ventricular pressure was changed acutely by arterial transfusion-bleeding into an open-air ventricular pressure reservoir that was either off or on a metaraminol intravenous drip. While maintaining ventricular pressure at several levels, the QRS duration was measured at 200 mm/s paper speed. The QRS duration correlated significantly with the left ventricular pressure in all 14 dogs examined. An average change in ventricular by 100 mmHg was associated with a change of about 18% in the QRS duration. An acute ventricular pressure elevation impairs the ventricular conduction, which may contribute to ventricular pressure-related arrhythmogenicity.

Anatomical origin of pressure-related ventricular ectopic rhythms.

In order to determine the origin of pressure-related ectopic rhythms, the main arteries were clamped in 11 anesthetized dogs, or the arteries or veins were transfused, while on or off metaraminol. The epicardial right atrial electrogram, the intracavity electrograms and the pressure of the two ventricles were recorded. Sinus rhythm was associated with 64/64 (100%) of the control periods off metaraminol, but only 19/50 (38%) of the clamping of the main arteries (P << 0.0005). In 14/27 aortic clampings ectopic beats appeared from the left ventricle and in 13/27 from the right one. In 4/23 clampings of the pulmonary artery ectopic beats appeared from the left ventricle and in 15/23 from the right one (P < 0.05). Sinus rhythm was associated with significantly lower left ventricular systolic pressure than any ventricular arrhythmia. The left ventricular systolic pressure associated with ectopic rhythms from the left ventricle was significantly (P < 0.005) higher than that associated with those from the right ventricle. The right ventricular systolic pressure during sinus rhythm was significantly (P < 0.005) lower than that during ectopic rhythm from any ventricle. It is concluded that a rise in the pressure of one ventricle tends to cause ventricular ectopic rhythms originating predominantly, but not exclusively, from this ventricle. The origin of ventricular ectopic rhythms from the right ventricle does not preclude that the arrhythmia may respond favorably to lowering of the systemic pressure.

Effect of adrenergic blockade on pressure-related ventricular arrhythmias.

This paper examines whether adrenergic blockade (B1) may prevent the arrhythmogenic effect of acute arterial pressure (AP) elevation. In 7 anesthetized dogs iv propranolol (0.2 mg/kg) was given and in another 2 dogs stellate ganglion excision was performed. Before and after these B1 manoeuvres the AP was repeatedly increased by either elevating an open-air arterial pressure reservoir or administering iv metaraminol and decreased by abating the pressure reservoir. In a continuous recording of AP and ECG the systolic (S) AP and the presence (or absence) of ventricular arrhythmia (A) was noted. Before B1 A was noted in 652/1715 (38.0%) 5-sec periods at a SAP of 160.3 +/- 69.9 mm Hg which was significantly higher than in the 1063 5-sec periods without A (104.2 +/- 54.3) in all experiments. Following B1 it was impossible to cause A in 3 experiments. In the remaining experiments the A incidence was reduced (significantly in 5/9 experiments) to a total of 253/983 (25.7%) periods (P less than 0.001). In the 5/9 experiments with post-B1 A, the mean SAP was higher with (185.0 +/- 97.9 mm Hg) than without A (113.7 +/- 59.9 mm Hg) (significantly in 2/9 experiments). Following fitting of the SAP distributions before and after B1 to their common distribution (i.e. the same AP), the incidence of A was higher before than after B1 in all experiments (significantly in 7/9). It is concluded that B1 has an antiarrhythmic action on AP-related A. This antiarrhythmic effect seems to be due partly to an antihypertensive effect of B1 and partly to an antiarrhythmic effect of B1 for a given AP.

[The significance of endodontic therapy before an endodontic surgery]. / E semasia tes endodontikes therapeias ste cheirourgike endodontia.

Conventional Endodontic therapy is the treatment of choice for pulp disease and periapical lesions due to pulp necrosis. Although the percentage of success of endodontic therapy is fairly high, in several cases endodontic therapy cannot perform accurately, or it is impossible to undertaken so as to avoid extraction of tooth. Before an endodontic surgery is performed a conventional endodontic therapy must be attempted because this increases prognosis and reduces the possibilities of failure. The possible presence of lateral canals, communication between periodontal ligament and infected canals through dentinal tubules and the potential hermetic reverse filling, are ones of the main factors which support the necessity of endodontic therapy. Apart from these, many cases have been reported where the basic factor of endodontic surgery failure was not the awkward operations, but the absence of the root canal filling. In this paper authors describe the basic steps and techniques which must be followed so as to avoid the failure of endodontic surgery.

Response of tertiary centres to pressure changes. Is there a mechano-electrical association?

STUDY OBJECTIVE: To investigate the mechanism of pressure related ventricular arrhythmias by examining them during atrioventricular (AV) block. DESIGN: Complete AV block, where all ventricular beats are ectopic, was induced by AV node ablation and/or by toxic digitalisation, and rhythm changes were studied while arterial blood pressure was repeatedly raised and lowered. SUBJECTS: 15 anaesthetised mongrel dogs, weight 15-28 kg, were used. AV block was induced in eight by chemical or mechanical ablation of the AV node. In five of these and in seven other dogs, 5.0-7.5 mg digoxin was also given. MEASUREMENTS AND RESULTS: Following AV block due to ablation, a heart rate increase (or no change) was found in 87.5% of 56 arterial pressure increases produced by elevation of an open arterial blood reservoir or by metaraminol infusion, but in only 21.8% of 55 pressure decreases caused by arterial bleeding (p much less than 0.001). Following AV block due to digitalisation, the equivalent figures were 96% of 50 pressure increases and 27.3% of 55 pressure decreases (p much less than 0.001). While arterial pressure was increased there was moderate acceleration of the escape rhythm, then appearance of premature ventricular beats, then non-sustained and finally sustained ventricular tachycardia. The reverse occurred, with some hysteresis, on decreasing the arterial pressure. In five of the digitalised animals, arterial pressure reduction to nearly zero caused reproducible sudden arrest, with resumption of the ordinary escape rhythm on increasing the pressure again. CONCLUSIONS: The findings suggest the possibility of two kinds of ectopic rhythm in AV block: the "normal" escape rhythm which is only moderately affected by arterial pressure changes; and an "abnormal" faster pressure dependent rhythm which is generated by high arterial pressure and abolished by pressure near zero, as if there were a mechano-electrical association. This abnormal rhythm may prevail completely in digitalis toxicity so that if cardiac arrest occurs, no automaticity can be expected to appear unless arterial pressure is raised.

Early detection of silent ischemia after bypass grafting.

Silent ischemia (SI) is one of the predictable factors for crises after coronary artery bypass grafting. During the last six months 31 consecutive patients (range of age fifty-one to seventy-one years) underwent twenty-four-hour electrocardiographic monitoring (Holter) in the second postoperative week under ambulatory hospital conditions (total time 750 hours). The patients were investigated by two-channel ST segment Holter (CM1CM5). The results of the analysis were controlled by two independent observers. Criteria for SI were horizontal or downslope ST depression greater than or equal to 1 mm greater than or equal to 1 minute. Five patients (16%) underwent two to eight SI crises/twenty-four hours (mean 4.3).

[Formation, composition, clinical implications and methods for removing the smeared layer from root canal walls]. / Echematismos, systase, klinike semasia kai methodoi gia ten apomakrynse tou epichrismatos (smeared layer) apo to toichoma ton rizikon solenon.

A layer, which is readily detectable at higher magnifications with scanning electron microscope (sem) is consistently seen on canal walls that have been endodontically instrumented. This layer in the international bibliography reported as smeared layer. The surface of this layer is amorphous, irregular and granular. Although the composition of this layer has not been completely determined, it probably contains fine inorganic particles of dentin produced by mechanical preparation of root canal walls. As well as some organic material from necrotic or vital pulp tissue, bacteria and blood cells. The clinical importance of the smeared layer is still not fully understood. It may be beneficial since it is known to plug the orifices of the dentinal tubules and to reduce the permeability of dentin. In addition, the Smeared layer covering prepared areas of root canal prevents medicaments and filling materials from penetrating the dentinal tubules on even contacting the canal wall. The formation of this layer, the composition, the clinical importance and various methods for removing the smeared layer from the system of root canals, is the object of this paper.

[Perforation during endodontic treatment]. / Iatrogeneis diatreseis kata te diarkeia tes endodontikes therapeias.

Perforations of the pulp chamber wall and area of root may occur during access opening of the pulp chamber and during root canal instrumentation. The authors in this paper describe in details the factors that can lead to perforations of pulp chamber or area of the root, the treatment and factors that affecting the repair and the prognosis of the perforations.