Method for estimating critical exponents in percolation processes with low sampling.

In phase-transition phenomena, the estimation of the critical point is crucial for the calculation of the various critical exponents and the determination of the universality class they belong to. However, this is not an easy task, since a large amount of realizations is needed to eliminate the noise in the data. In this paper, we introduce a novel method for the simultaneous estimation of the critical point p(c) and the critical exponent ß/ν, applied for the case of "explosive" bond percolation on two-dimensional square lattices and Erdös-Rényi networks. The results show that with only a few hundred realizations, it is possible to acquire accurate values for these quantities. Guidelines are given at the end for the applicability of the method to other cases as well.

Percolation of randomly distributed growing clusters: finite-size scaling and critical exponents for the square lattice.

We study the percolation properties of the growing clusters model on a 2D square lattice. In this model, a number of seeds placed on random locations on the lattice are allowed to grow with a constant velocity to form clusters. When two or more clusters eventually touch each other they immediately stop their growth. The model exhibits a discontinuous transition for very low values of the seed concentration p and a second, nontrivial continuous phase transition for intermediate p values. Here we study in detail this continuous transition that separates a phase of finite clusters from a phase characterized by the presence of a giant component. Using finite size scaling and large scale Monte Carlo simulations we determine the value of the percolation threshold where the giant component first appears, and the critical exponents that characterize the transition. We find that the transition belongs to a different universality class from the standard percolation transition.

Crown dilaceration of permanent incisors following trauma to their primary predecessors.

Crown dilaceration of a permanent tooth constitutes 3% of traumatic injuries to developing teeth. It usually involves the maxillary incisors and less frequently their mandibular counterparts. This report concerns a patient, whose primary mandibular central incisors, following a fall at the age of 14 months, sustained partial avulsion with displacement. The teeth were repositioned by the father, with the aid of a pediatrician, and without the assistance of a dentist. The patient presented at the age of 8 years, and, following clinical and radiographic examination, a diagnosis was made of crown dilaceration with lingual displacement of the incisal third of the permanent mandibular central incisors, and hypoplastic enamel on all but the gingival third of their crowns. In addition to this, a supernumerary tooth was discovered labial to and between the mandibular right permanent central incisor and the mandibular right primary lateral incisor. After a brief review of the literature, the treatment of this patient is described and the restoration of the dilacerated teeth, followed by a discussion on crown dilaceration and issues concerning the restoration of such teeth.

Possibilities of scar treatment after thoracic surgery.

During a ten year observation period it was found that scar formation after thoracic surgery is influenced by various factors: metabolism, operative technique and factors of a general nature. On the basis of these findings, a study was carried out to investigate the effect of the scar-specific Contractubex gel (Merz+Co., D-Frankfurt/Main), containing 10% onion extract, 50 U sodium heparin per g of gel and 1% allantoin, in the treatment of children who underwent thoracic surgery and to evaluate its effect on scar development. Before and during the six-month treatment period, both macromorphology and scar colour were assessed; furthermore, a global evaluation of the therapeutic result was made. Additionally, the scars were characterized after a six-month treatment-free follow-up period. The results of 38 Contractubex-treated and 27 untreated patients were compared. In the treated scars, the global evaluation of the therapeutic result was better than in the untreated scars. In the Contractubex group, the rating was "good" and "very good" in 84% of cases, as compared to 59% of the untreated cases. In the treated group, the increase in scar size was markedly lower than in the untreated patients. The treated scars showed a tendency towards quicker paling than the untreated scars. In the treated group, the conversion of primary physiological scars to unphysiological scars (hypertrophic or keloidal scars) was less frequent than in the untreated group. The tolerability of the product was very good in 37 of the 38 treated patients, and good in one patient. All scar-specific effects of Contractubex continued to persist after the end of treatment.

[Intraoperative anaphylactic shock due to a latex allergy]. / Intraoperativer anaphylaktischer Schock aufgrund einer Latexallergie.

Delayed hypersensitivity to rubber chemicals is well known, but there has been an increasing number of reports of immediate-type hypersensitivity due to latex causing contact urticaria, angioedema, bronchial asthma, and anaphylactic shock in adults. We report a 10-year-old boy who developed anaphylactic shock during surgery due to surgical gloves containing latex. The patient was atopic and had a history of neurodermatitis and localized angioedema on exposure to rubber. There had been two previous uneventful surgical procedures. Thirty-five minutes after induction of anesthesia and 5 min after laparotomy for appendectomy there was an acute onset of increased airway pressure, oxygen desaturation, and profound hypotension. The circulation and gas exchange stabilized after treatment with oxygen, intravenous fluids, epinephrine, H1 and H2 blockers, aminophylline, and methylprednisolone. A positive skin test and RAST revealed a latex allergy. Latex can cause life-threatening allergic reactions in patients with a history of rubber allergy or frequent exposure to latex products.