Ghost ileostomy: Real and potential advantages

Loop ileostomy is created to minimize the clinical impact of colorectal anastomotic leak. However, a lot of complications may be associated with ileostomy presence and with its reversal. Moreover, patients hardly accept the quality of life resulting from ileostomy. We describe a simple technique (ghost ileostomy) to combine all the advantages of a disposable ileostomy without entailing its complications in patients submitted to low rectal resection. In case of uneventful postoperative course, the ghost ileostomy prevents all complications related to defunctioning ileostomy. At the same time, in case of anastomotic leakage, the ghost ileostomy is easily and safely converted into a defunctioning ileostomy. © 2010 Elsevier Inc. All rights reserved

Long-term evaluation of bulking agents for the treatment of fecal incontinence: clinical outcomes and ultrasound evidence

BACKGROUND:The injection of bulking agents into the anal canal has been reported to help patients with fecal incontinence. Although it has been advocated as a safe and effective option, substantial data concerning long-term efficacy are still lacking, and the resorption process of the implants has not yet been carefully studied. The aim of our study was to investigate the long-term outcomes of bulking agents for the treatment of fecal incontinence and the behavior of implanted materials in the anorectum. METHODS: At a median follow-up of 7 years, 19 patients with idiopathic fecal incontinence who had received bulking agent implants were evaluated. Clinical, manometric and ultrasound assessments were carried out. RESULTS: The clinical improvements that were achieved in the short term were not maintained over time. For each patient, the number of implants that could no longer be identified on ultrasound was significantly correlated with poorer clinical long-term outcomes. On average, only 14 % of the originally injected volume was still detectable. CONCLUSIONS: In the long term, perianally injected bulking agents seem to lose effectiveness. The ultrasound assessment suggests that the process of resorption is almost complete, and the implants are no longer effective in treating incontinence

Transport mechanisms in Co-doped ZnO (ZCO) and H-irradiated ZCO polycrystalline thin films

In the present study, the electrical resistivity (ρ) as a function of the temperature (T) has been measured in polycrystalline ZnO, Co-doped ZnO (ZCO) and H irradiated ZCO (HZCO) samples, in the 300–20 K range. The achieved results show impressive effects of Co doping and H irradiation on the ZnO transport properties. The Co dopant increases the ZnO resistivity at high T (HT), whereas it has an opposite effect at low T (LT). H balances the Co effects by neutralizing the ρ increase at HT and strengthening its decrease at LT. A careful analysis of the ρ data permits to identify two different thermally activated processes as those governing the charge transport in the three materials at HT and LT, respectively. The occurrence of such processes has been fully explained in terms of a previously proposed model based on an acceptor impurity band, induced by the formation of Co-oxygen vacancy complexes, as well as known effects produced by H on the ZnO properties. The same analysis shows that both Co and H reduce the effects of grain boundaries on the transport processes. The high conductivity of HZCO in the whole T-range and its low noise level resulting from electric noise spectroscopy make this material a very interesting one for technological applications

Selective Effects of the Host Matrix in Hydrogenated InGaAsN Alloys: Toward an Integrated Matrix/Defect Engineering Paradigm

In dilute nitride InyGa1−yAs1−xNx alloys, a spatially controlled tuning of the energy gap can be realized by combining the introduction of N atoms—inducing a significant reduction of this parameter—with that of hydrogen atoms, which neutralize the effect of N. In these alloys, hydrogen forms N–H complexes in both Ga-rich and In-rich N environments. Here, photoluminescence measurements and thermal annealing treatments show that, surprisingly, N neutralization by H is significantly inhibited when the number of In-N bonds increases. Density functional theory calculations account for this result and reveal an original, physical phenomenon: only in the In-rich N environment, the InyGa1−yAs host matrix exerts a selective action on the N–H complexes by hindering the formation of the complexes more effective in the N passivation. This thoroughly overturns the usual perspective of defect-engineering by proposing a novel paradigm where a major role pertains to the defect-surrounding matrix