Useful representations of series solutions for transport problems

Simple techniques are presented for rearrangement of an infinite series in a systematic way such that the convergence of the resulting expression is accelerated. These procedures also allow calculation of required boundary derivatives. Several examples of conduction and diffusion-reaction problems illustrate the methods.

Free volume and water uptake in a copolymer hydrogel series

A copolymer of X-hydroxyethyl methacrylate (HEMA) with 2-ethoxy ethyl methacrylate (EEMA) was synthesized and the molecular mobility, free volume, and density properties examined as a function of composition. These properties were correlated with the equilibrium water uptake in order to determine which of the properties were most influential in causing high water sorption, as these materials are suitable candidates for hydrogel systems. It was found that the polar HEMA repeat unit results in a rigid, glassy sample at room temperature due to the high degree of hydrogen bonding between chains whereas high EEMA content leads to rubbery samples with subambient glass transition temperatures. The free volume properties on the molecular scale measured by positron annihilation Lifetime spectroscopy (PALS) showed that higher HEMA content led to smaller, fewer holes and a lower free volume fraction than EEMA. Therefore the high water uptake of HEEMA-containing copolymers is largely related to the high polarity of the HEMA unit compared to EEMA, despite the low content of free volume into which the water can initially diffuse. Trends in density with copolymer composition, as measured on a macroscopic level, differs to that seen by PALS and indicates that the two techniques are measuring different scales of packing. (C) 1998 John Wiley & Sons, Inc.

The structure of quantum Lie algebras for the classical series, B-l, C-l and D-l

The structure constants of quantum Lie algebras depend on a quantum deformation parameter q and they reduce to the classical structure constants of a Lie algebra at q = 1. We explain the relationship between the structure constants of quantum Lie algebras and quantum Clebsch-Gordan coefficients for adjoint x adjoint --> adjoint We present a practical method for the determination of these quantum Clebsch-Gordan coefficients and are thus able to give explicit expressions for the structure constants of the quantum Lie algebras associated to the classical Lie algebras B-l, C-l and D-l. In the quantum case the structure constants of the Cartan subalgebra are non-zero and we observe that they are determined in terms of the simple quantum roots. We introduce an invariant Killing form on the quantum Lie algebras and find that it takes values which are simple q-deformations of the classical ones.

On the use of trace additions of Sn to enhance sintered 2xxx series Al powder alloys

The mechanical properties of a typical sintered aluminium alloy (Al-4.4Cu-0.8Si-0.5Mg) have been improved by the simultaneous use of trace additions of Sn, high sintering temperatures and modified heat treatments. Tin increases densification, but the Sn concentration is limited to less than or equal to 0.1wt% because incipient melting occurs during solution treatment at higher Sn levels. A sintering temperature of 620 degrees C increases the liquid volume over that formed at the conventional 590 degrees C sintering temperature. However, the higher sintering temperature results in the formation of an embrittling phase which can be eliminated if solution treatment is incorporated into the sintering cycle (a modified TS heat treatment). These conditions produce a tensile strength of 375 MPa, an increase of nearly 20% over the unmodified alloy. (C) 1999 Elsevier Science S.A. All rights reserved.

Structure of a putative ancestral protein encoded by a single sequence repeat from a multidomain proteinase inhibitor gene from Nicotiana alata

Background: The ornamental tobacco Nicotiana alata produces a series of proteinase inhibitors (Pls) that are derived from a 43 kDa precursor protein, NaProPl. NaProPl contains six highly homologous repeats that fold to generate six separate structural domains, each corresponding to one of the native Pls. An unusual feature of NaProPl is that the structural domains lie across adjacent repeats and that the sixth Pl domain is generated from fragments of the first and sixth repeats. Although the homology of the repeats suggests that they may have arisen from gene duplication, the observed folding does not appear to support this. This study of the solution structure of a single NaProPl repeat (aPl1) forms a basis for unravelling the mechanism by which this protein may have evolved, Results: The three-dimensional structure of aPl1 closely resembles the triple-stranded antiparallel beta sheet observed in each of the native Pls. The five-residue sequence Glu-Glu-Lys-Lys-Asn, which forms the linker between the six structural domains in NaProPl, exists as a disordered loop in aPl1. The presence of this loop in aPl1 results in a loss of the characteristically flat and disc-like topography of the native inhibitors. Conclusions: A single repeat from NaProPl is capable of folding into a compact globular domain that displays native-like Pl activity. Consequently, it is possible that a similar single-domain inhibitor represents the ancestral protein from which NaProPl evolved.

John Waldridge, The Leaven of the Ancients: Suhrawardi and the Heritage of the Greeks, SUNY Series in Islam (Albany: State University of New York Press, 1999). Pp. 323

In the Leaven of the Ancients, John Walbridge studies the appropriation of non–Peripatetic philosophical ideas by an anti–Aristotelian Islamic philosopher, Shihab al-Din al-Suhrawardi (d. 1191). He proposes a comprehensive explanation of the origin of Suhrawardi's philosophical system, a revival of the “wisdom of the Ancients” and its philosophical affiliations “grounded” in Greek philosophy (p. xiii). Walbridge attempts to uncover the reasons for Suhrawardi's rejection of the prevailing neo–Aristotelian synthesis in Islamic philosophy, Suhrawardi's knowledge and understanding of non–Aristotelian Greek philosophy, the ancient philosophers Suhrawardi was attempting to follow, the relationship between Suhrawardi's specific philosophical teachings (logic, ontology, physics, and metaphysics), and his understanding of non–Aristotelian ancient philosophy and the relationship between Suhrawardi's system and the major Greek philosophers, schools, and traditions—in particular the Presocratics, Plato, and the Stoics (p. 8). Copyright © 2003 Cambridge University Press

Syntheses, electrochemistry and photophysical properties of a series of meso-pyridylpentafluorophenylporphyrins

This work presents the synthesis and characterization of a series of substituted pyridylpentafluroporphyrins, including the separation of the cis- and trans-isomers, the latter being characterized by X-ray crystallography. The spectroscopic and electrochemical properties of the series are dependent on the number of electron withdrawing pentafluorophenyl substituent, but they do not depend on the symmetry of the molecule. Ongoing from the monosubstituted to the more substituted pentafluorophenyl porphyrin H(2)(MPyTFPP) derivative, the Soret bands are slightly red-shifted and their quantum fluorescence yields range from 0.035 to 0.046, consistent with the value of 0.045 for the fully substituted 5,10,15,20-tetrapentafluorophenylporphyrin (dichloromethane solutions). The redox potentials of the reductive processes of monoanion and dianion formation are also sensitive to the number of pentafluoro substituents, shifting 180 mV to more positive values for the P(0)/P(-1) process ongoing from the monopentafluoro to the tris-pentafluorophenyl substituted derivative.

Management of brachial plexus region tumours and tumour-like conditions: relevant diagnostic and surgical features in a consecutive series of eighteen patients

Tumours of the brachial plexus region are rare and most publications are case reports or studies with a small series of patients. The aim of this study is to present our experience in managing these lesions. We review 18 patients with tumours in the brachial plexus region submitted to surgical treatment in a 6 year period, including their clinical presentation, neuro-imaging data, surgical findings and outcome. The tumours comprised a heterogeneous group of lesions, including schwannomas, neurofibromas, malignant peripheral nerve sheath tumour (MPNST), sarcomas, metastases, desmoids and an aneurysmal bone cyst. The most common presentation was an expanding lump (83.33%). Eleven tumours were benign and 7 were malignant. Neurofibromatosis was present in only 2 patients (11.11%). Gross total resection was achieved in 14 patients and sub-total resection in the others. Only 3 patients presented with new post-operative motor deficits. The incidence of complications was low (16.5 %). The majority of tumours were benign and most of them could be excised with a low incidence of additional deficits. Some of the malignant tumours could be controlled by surgery plus adjuvant therapy, but this category is still associated with high morbidity and mortality rates.

Tessier No. 4 Facial Cleft: Evolution of Surgical Treatment in a Large Series of Patients

Background: Tessier no. 4 facial cleft is a rare, complex, and challenging craniofacial malformation. The present article aims to describe different clinical features evidenced in 21 cases of this malformation, discussing a 20-year experience with and evolution of its surgical treatment. Methods: Some demographic data, clinical features, and reconstructive results were evaluated retrospectively. These patients have been evaluated and treated in three specialized Brazilian craniofacial centers. Nineteen were already operated on, with a mean follow-up of 3.5 years (range, 1 to 20 years). Results: Sex distribution showed a male prevalence (2: 1). The average age of initial treatment was 5.4 years. Four cases were affected on the right side of the face, seven on the left, and 10 bilaterally. Six patients had other rare associated facial clefts, including nos. 5 (three patients), 7, 9, and 10. Cleft upper lip was evidenced in all patients, and maxillary hypoplasia was present in five and maxilla cleft in eight. Lower eyelid coloboma was seen in almost every case (19 patients); 10 of these had medial canthus dystopia. Four patients had amniotic bands in the limbs. Surgical repair was individualized to each patient. Surgical experience gained with these patients allowed the authors to develop some technical modifications, which have improved aesthetic results, camouflaging scars into natural folds and anatomical units, without compromising functional outcomes. Conclusions: The great majority of Tessier no. 4 facial clefts can be appropriately treated using local flaps. Classic techniques are extremely useful, but long-term results could be improved if the technical modifications described were adopted. (Plast. Reconstr. Surg. 122: 1505, 2008.)

FIBRIN GLUE APPLICATION IN MICROVASCULAR ANASTOMOSIS: COMPARATIVE STUDY OF TWO FREE FLAPS SERIES

Background: Since the first experiments with fibrin glue application in microvascular anastomoses in 1977, several studies have reported its benefits on suture reduction and anastomosis decreased time. In spite of that, clinical experience has been limited to two neurosurgical and two replantation case series, all of them with good results. This study was conducted to evaluate the feasibility and the potential benefits of fibrin glue application in free flaps. Methods: We performed 24 free flaps in 24 patients, from March 2005 to June 2006. Twenty were included in this study. They were divided into two groups according to the anastomosis technique: conventional group (n = 7 patients) and fibrin glue group (n = 13 patients). In the conventional group, the anastomosis was performed with interrupted sutures, whereas in the fibrin glue group, they were performed using less sutures and fibrin glue application. Results: The application of fibrin glue cut by half the number of sutures required to complete the anastomoses. The mean arterial and venous anastomotic times in the conventional group were 27.2 and 24.0 minutes, respectively. In the fibrin glue group, they were 13.6 and 12.6 minutes, respectively. All these differences were statistically significant. There was no significant difference of ischemic time between two groups (P = 0.26). The survival rate of the flaps was similar in both groups: 84.6% (11 of 13) in the fibrin glue group and 85.7% (6 of 7) in the conventional group (P = 1.0). Conclusions: Fibrin glue application in free flaps was feasible and allowed us to complete the anastomoses with fewer sutures and less time. The survival rate of the flaps was not adversely affected by the fibrin glue. (C) 2008 Wiley-Liss, Inc. Microsurgery 29:24-28, 2009.

Case Series: Sensory Intolerance as a Primary Symptom of Pediatric OCD

Introduction. Marked intolerance or intrusive re-experiencing of ordinary sensory stimuli that in turn drive functionally impairing compulsive behaviors are occasionally seen in voting children with OCD. Methods. We describe a number of children with DSM-IV OCD ascertained from of family genetic study of pediatric OCD, whose intolerance: of ordinary sensory stimuli created significant subjective distress and time-consuming ritualistic behavior that was clinically impairing. Results. In each case these sensory symptoms were the primary presenting symptoms and were experienced in the absence of intrusive thoughts, images, or ideas associated with ""conventional"" OCD symptoms. Conclusions. These symptoms suggest abnormalities in sensory processing and integration in at least a subset of OCD patients. Recognition of these sensory symptoms and sensory-driven behaviors as part of the broad phenotypic Variation in children with OCD could help clinicians more easily identify OCD patients and,facilitate treatment.

Obstetric Outcome in Pregnant Women on Long-term Dialysis: A Case Series

Background: Although still uncommon, pregnancy frequency in women on maintenance hemodialysis therapy has increased in the past 20 years. Most published reports suggest that intensified hemodialysis regimens result in better pregnancy outcomes. The small number of patients investigated in all reported series is the main limitation of the available studies. Study Design: Retrospective case series. Setting & Participants: Data for all pregnancies that occurred in 1988-2008 in women undergoing maintenance hemodialysis (52 pregnancies) at the Sao Paulo University Medical School (Sao Paulo, Brazil). Outcomes & Measurements: We analyzed maternal and fetal outcomes of 52 pregnancies, as well as their relationship with various clinical, laboratory, and hemodialysis parameters, such as pre-eclampsia, pregnancy before or after dialysis therapy, hemodialysis dose, polyhydramnios, anemia, and predialysis serum urea level. In addition, logistic regression models for a composite adverse fetal outcome (perinatal death or extremely premature delivery) and linear regression models for birth weight were built. Results: 87% overall rate of successful delivery, with a mean gestational age of 32.7 +/- 3.1 weeks. Pre-eclampsia was associated with a poor prognosis compared with pregnancies without pre-eclampsia: a successful delivery rate of 60% versus 92.9% (P = 0.02), extremely premature delivery rate of 77.8% versus 3.3% (P = 0.001), lower gestational age (P = 0.001), and birth weight (P = 0.001). Patients with an adverse composite fetal outcome had a higher frequency of pre-eclampsia (P = 0.001), lower frequency of polyhydramnios (P = 0.03), lower third-trimester hematocrit (P = 0.03), and higher predialysis serum urea level (P = 0.03). The same results were seen for birth weight. Limitations: Retrospective data analysis. The absence of creatinine clearance measurements did not allow evaluation of the impact of residual renal function on fetal outcome. Conclusions: Outcomes of pregnancy in women undergoing hemodialysis often are good. Preeclampsia, third-trimester hematocrit, polyhydramnios, and predialysis serum urea level are important variables associated with fetal outcome and birth weight. Am J Kidney Dis 56:77-85. (C) 2010 by the National Kidney Foundation, Inc.Inc