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Objective: Nutritional deficiencies are known side-effects of
bariatric surgeries, specifically in those that bypass the proximal intestine.
Therefore, in clinical practice, vitamin and mineral supplementations are often
necessary after such operations. It was our intention to evaluate, whether
alimentary deficiencies occur with the same frequency in patients following
Sleeve-Gastrectomy (SG) compared to Roux-en-Y Gastric
Bypass (RYGB) surgeries. Methods: We
conducted a retrospective data analysis of 171 patients (121 RYGB, 50 SG).
Vitamin levels were compared between SG and RYGB patients over the first
post-operative year. Furthermore, regression analysis was performed with regard
to vitamin and iron supplementations and their recommended dosages.
Complications occurring within the first post-surgical year were documented as
well. Results: Other
than vitamin B6 deficiency, which was found to be more frequent in SG patients,
there was no other significant difference regarding the type of operation and
the number of patients who had these deficiencies. There was no significant
difference in average vitamin and iron levels between RYGB and SG. A minimum dose
of 1000 IU vitamin D per day was necessary to affect vitamin D levels. The
intramuscular administration of vitamin B12 was the only route found to be effective. Complications within the first
year were rare. Conclusions: Against
common assumptions, vitamin and iron deficiencies in SG patients are not less
frequent in the first post-surgical year in comparison to RYGB patients. Standard supplementations should include iron in premenopausal
women: Vitamin D at least 1000 IU per day and vitamin B12 i.m. administration
in case of a deficiency.
Hydrogenated doped silicon thin films deposited using RF (13.56 MHz) PECVD were studied in detail using micro Raman spectroscopy to investigate the impact of doping gas flow, film thickness, and substrate type on the film characteristics. In particular, by deconvoluting the micro Raman spectra into amorphous and crystalline components, qualitative and quantitative information such as bond angle disorder, bond length, film stress, and film crystallinity can be determined. By selecting the optimum doped silicon thin film deposition conditions, and combining our p-doped and n-doped silicon thin films in different heterojunction structures, we demonstrate both (i) an efficient field effect passivation and (ii) further improvement to c-Si/a-Si:H(i) interface defect density with observed improvement in implied open-circuit voltage VOC and minority carrier lifetimes across all injections levels of interest. In particular, the heterojunction structure (a-Si:H(p)/a-Si:H(i)/c-Si(n)/a-Si:H(i)/a-Si:H(p)) demonstrates a minority carrier lifetime of 2.4 ms at an injection level of 1015 cm-3, and a high implied open-circuit voltage of 725 mV. Simulation studies reveal a strong dependence of the interface defect density Dit on the heterojunction silicon wafer solar cell performance, affected by the deposition conditions of the overlying doped silicon thin film layers. Using our films, and a fitted Dit of 5 × 1010 cm-2·eV-1