1,721,021 research outputs found
A scoring system for early prognostic assessment after neonatal seizures
No full textOBJECTIVE: The aim of this study was to devise a scoring system that
could aid in predicting neurologic outcome at the onset of neonatal
seizures.
METHODS: A total of 106 newborns who had neonatal seizures and
were consecutively admitted to the NICU of the University of Parma
from January 1999 through December 2004 were prospectively
followed-up, and neurologic outcome was assessed at 24 months’
postconceptional age. We conducted a retrospective analysis on this
cohort to identify variables that were significantly related to adverse
outcome and to develop a scoring system that could provide early
prognostic indications.
RESULTS: A total of 70 (66%) of 106 infants had an adverse neurologic
outcome. Six variables were identified as the most important independent
risk factors for adverse outcome and were used to construct a
scoring system: birth weight, Apgar score at 1 minute, neurologic examination
at seizure onset, cerebral ultrasound, efficacy of anticonvulsant
therapy, and presence of neonatal status epilepticus. Each variable
was scored from 0 to 3 to represent the range from “normal” to
“severely abnormal.” A total composite score was computed by addition
of the raw scores of the 6 variables. This score ranged from 0 to 12.
A cutoff score of 4 provided the greatest sensitivity and specificity.
CONCLUSIONS: This scoring system may offer an easy, rapid, and reliable
prognostic indicator of neurologic outcome after the onset of
neonatal seizures. A final assessment of the validity of this score in
routine clinical practice will require independent validation in other
centers. Pediatrics 2009;124:e580–e58
Memory effect in melting behaviour, crystallization kinetics and morphology of poly(propylene terephthalate)
Full text linkCrystallization kinetics and melting behaviour of poly(propylene terephthalate) (PPT) were investigated by means of differential scanning calorimetry and hot-stage optical microscopy. Isothermal crystallization kinetics was analysed according to the Avrami treatment. The effects of temperature and duration of melting on the overall rate of isothermal crystallization were studied: the rate was found to decrease with increasing melting temperature and melting time. This result was discussed on the basis of the gradual destruction of predetermined athermal nuclei. Values of the Avrami exponent close to 3 were obtained, regardless of the adopted thermal treatment and the crystallization temperature, Tc, in agreement with a crystallization process originating from predetermined nuclei and characterized by three-dimensional spherulitic growth. As a matter of fact, spacefilling spherulites were observed by optical microscopy at all Tc's, independent of the applied thermal treatments. For each of them, the rate of crystallization became lower as Tc increased, as usual at low undercooling where the crystallization process is controlled by nucleation. The observed multiple endotherms, which are commonly displayed by polyesters, were influenced by Tc and ascribed to melting and recrystallization processes. Linear and non-linear treatments were applied in order to estimate the equilibrium melting temperature for PPT, by using the corrected melting temperatures. The non-linear estimation yielded an about 33°C higher value with respect to the one obtained by means of the linear approach. Through the analysis of secondary nucleation theory, the classical II→III transition was found to occur at a temperature of 194°C. The average work of chain folding for nucleation was determined to be c. 5.2 kcal/mol. The heat of fusion was correlated to the specific heat increment for samples with different degree of crystallinity and the results were interpreted on the basis of the existence of an interphase, whose amount was found to depend on the thermal treatment the polymer was subjected to
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Retting Process as a Pretreatment of Natural Fibers for the Development of Polymer Composites
No full textThe development of high-performance materials made from natural resources is increasing worldwide. Within this framework, natural fiber reinforced polymeric composites now experience great expansion and applications in many fields, ranging from the automotive to the construction sector. The great challenge in producing composites containing natural fibers and with controlled features is connected to the great variation in properties and characteristics of fibers. The quality of the natural fibers is largely determined by the efficiency of the treatment process and can dramatically influence the properties of the final composites. The overall fiber extraction processes, applied to vegetable fibers, is called retting and consists in the separation of fiber bundles from the cuticularized epidermis and the woody core cells. Today, many efforts are being made to optimize the retting methods in terms of fiber quality production, reduction of environmental issues and production costs. This chapter aims to provide a classification and an overview of the retting procedures that have been developed during years and are applied to extract mainly bast fibers
Neonatal status epilepticus vs recurrent neonatal seizures: clinical findings and outcome.
No full textBackground: Although most children with status epilepticus have a good prognosis, its effects on
newborns are unclear.
Objective: We compare the neurodevelopmental consequences of recurrent seizures and status
epilepticus in newborns.
Methods: One hundred six newborns with video-EEG–confirmed seizures, consecutively admitted
to the neonatal intensive care unit of the University of Parma between January 1999 and
December 2004, were enrolled in the study. Fifty-one were preterm and 55 were full-term newborns.
Neonatal status epilepticus was defined as continuous seizure activity for at least 30
minutes or recurrent seizures lasting a total of 30 minutes without definite return to the baseline
neurologic condition of the newborn between seizures. Neurologic outcome was assessed at
24 months of corrected age.
Results: Thirty-six newborns had a normal outcome, 20 died, and 50 presented an adverse outcome.
All but 1 of the 26 subjects with neonatal status epilepticus had an adverse outcome. Birth
weight, severely abnormal cerebral ultrasound scans, and status epilepticus were independent
predictors of abnormal outcome. Depending on gestational age (GA), neonatal status epilepticus
seems to be a risk factor of adverse outcome in full-term newborns (GA 37 weeks: odds ratio
[OR] 20.312, 95% CI 2.417 to 170.679, p 0.006), and a risk factor of epilepsy in early
preterm and full-term newborns (GA 29 weeks: OR 10.500, 95% CI 1.211 to 91.026, p
0.033; GA 37 weeks: OR 6.517, 95% CI 1.321 to 32.148, p 0.021).
Conclusion: Newborns with status epilepticus are at high risk of severe neurologic disability and
postneonatal epilepsy. This is particularly evident in early preterm and full-term infants
Chemical Modification of Bisphenol A Polycarbonate by Reactive Blending with Cyclic Anhydrides Part 1: Reaction with Succinic Anhydride
No full textReactive blending with cyclic anhydrides in the melt is a promising process to modify the chemical structure of bisphenol A polycarbonate (PC) by insertion of ester moieties leading to consistent changes in the chemical and physical properties of PC. In particular, by the reaction with succinic anhydride it is possible to insert aliphatic moieties in the polymer backbone, decreasing the melt viscosity and the glass transition temperature of PC (and thus increase its processability). The reaction, that is catalysed by Lewis acids (e.g. titanium butoxide), proceeds through the formation of carbonyl carbonate groups that undergo decarboxylation leading to ester moieties. No side reactions have been detected by NMR analysis. The addition of phosphorous acid as catalyst quencher at the end of the process gives rise to polymers with good colour and thermal stability
Sclerosi multipla con esordio in età giovanile: uno studio retrospettivo clinico e terapeutico.
No full textNew route to poly(alkylene terephthalate)s by reaction of dimethyl terephthalate with cyclic carbonates
No full textA new route to poly(alkylene terephthalate)s by melt reaction of dimethyl terephtalate (DMT) with cyclic aliphatic carbonates such as ethylene carbonate and propylene carbonate is described. Poly(butylene carbonate) was used instead of the cyclic monomer for the synthesis of poly(butylene terepthalate). The polymers prepared by this alternative way presented a reduced amount of carboxyl end groups. These end groups are responsible for the poor thermal and hydrolytic stability of poly(alkylene terephthalate)s industrially prepared from DMT or phthalic acids and the corresponding diols. The thermal studies conducted on poly(propylene terephthalate) samples, obtained by this innovative procedure, confirmed the expected higher thermal stability. A detailed study of the mechanism, using a model compound, of this new route for polyesters synthesis together with a complete characterisation of the polymers prepared, is described
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