175 research outputs found
MONITORAGGIO DELLA CORROSIONE MICROBIOLOGICA INDOTTA SU ACCIAI INOSSIDABILI IN AMBIENTI CONTAMINATI DA BATTERI MANGANESE OSSIDANTI
Il manganese è un elemento necessario per la vita dei microrganismi. Molti enzimi hanno una specifica necessità di tale elemento sfruttandone, per esempio, la capacità redox. Da osservazioni effettuate su componenti di impianti industriali che operano in ambienti contaminati da batteri manganese ossidanti, è emersa la presenza in superficie di un biofilm di caratteristiche viscose e di colore scuro. Le analisi eseguite sui biofilm hanno evidenziato che tali depositi sono costituiti da ossidi e idrossidi di Mn. Una parte significante delle colonie batteriche identificate hanno mostrato la capacità di produrre MnO2 (1-2). La presenza di batteri manganese-ossidanti produce negli acciai inossidabili un tipico innalzamento del potenziale di corrosione. Questo spostamento verso valori più nobili, rende più aggressive le condizioni di corrosione a causa dell’avvicinamento del potenziale al potenziale di pitting dell’acciaio. Nel presente lavoro è stata monitorata la corrosione microbiologica di alcuni acciai inossidabili. I test sono stati condotti su acciai austenitici e austenoferritici, in campo e in acqua di fiume sintetica contaminata da batteri manganese ossidanti, utilizzando tecniche microbiologiche ed elettrochimich
Transplantation of Specific Human Astrocytes Promotes Functional Recovery after Spinal Cord Injury
Repairing trauma to the central nervous system by replacement of glial support
cells is an increasingly attractive therapeutic strategy. We have focused on the
less-studied replacement of astrocytes, the major support cell in the central
nervous system, by generating astrocytes from embryonic human glial precursor
cells using two different astrocyte differentiation inducing factors. The
resulting astrocytes differed in expression of multiple proteins thought to
either promote or inhibit central nervous system homeostasis and regeneration.
When transplanted into acute transection injuries of the adult rat spinal cord,
astrocytes generated by exposing human glial precursor cells to bone
morphogenetic protein promoted significant recovery of volitional foot
placement, axonal growth and notably robust increases in neuronal survival in
multiple spinal cord laminae. In marked contrast, human glial precursor cells
and astrocytes generated from these cells by exposure to ciliary neurotrophic
factor both failed to promote significant behavioral recovery or similarly
robust neuronal survival and support of axon growth at sites of injury. Our
studies thus demonstrate functional differences between human astrocyte
populations and suggest that pre-differentiation of precursor cells into a
specific astrocyte subtype is required to optimize astrocyte replacement
therapies. To our knowledge, this study is the first to show functional
differences in ability to promote repair of the injured adult central nervous
system between two distinct subtypes of human astrocytes derived from a common
fetal glial precursor population. These findings are consistent with our
previous studies of transplanting specific subtypes of rodent glial precursor
derived astrocytes into sites of spinal cord injury, and indicate a remarkable
conservation from rat to human of functional differences between astrocyte
subtypes. In addition, our studies provide a specific population of human
astrocytes that appears to be particularly suitable for further development
towards clinical application in treating the traumatically injured or diseased
human central nervous system
An expansion of the peer-tutoring paradigm: cross-age peer tutoring of social skills among socially rejected boys.
We examined the effects of a cross-age peer-tutoring program on the social skills of 2 sixth-grade and 2 kindergarten socially rejected and isolated boys. Peer tutoring consisted of the older boys conducting social skills training with their younger tutees. The frequency of positive social interactions increased for all 4 boys, with maintenance of treatment gains following a 5-week interval
Sexual Aggression and Victimization
MixIRT study of sexual aggression and victimization in adolescence based on AAUW questionnair
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