Scaled-Down c-Si and c-SiGe Wagon-Wheels for the Visualization of the Anisotropy and Selectivity of Wet-Chemical Etchants.

Wet etching offers an advantage as a soft, damage-less method to remove sacrificial material with close to nanometer precision which has become critical for the fabrication of nanoscale structures. In order to develop such wet etching solutions, screening of etchant properties like selectivity and (an)isotropy has become vital. Since these etchants typically have low etch rates, sensitive test structures are required to evaluate their etching behavior. Therefore, scaled-down single-crystalline Si (c-Si) and SiGe (c-SiGe) wagon-wheels were fabricated. First, the sensitivity of the c-Si wagon-wheels to detect anisotropic behavior of crystalline silicon in the alkaline etchants TMAH and NH4OH was demonstrated. Distinctive wagon-wheel patterns, characteristic for each material/etchant pair, were observed by top-down scanning electron microscopy (SEM) after anisotropic wet etching. Similar trends in crystallographic plane-dependent etch rates were obtained for both Si(100) and Si(110) substrates. Secondly, the etching of both c-Si and c-Si75Ge25 wagon-wheels in a typical selective etchant, peracetic acid (PAA), was evaluated. c-Si75Ge25 etching in PAA resulted in isotropic etching. Selectivity values were calculated based on two methods: the first by measurement of the sidewall loss of the spokes of the wagon-wheel, the second, indirect method, through measurement of the spoke retraction lengths. Both methods give comparable values, but the latter method can only be used after a certain critical etching time, after which the spoke tips have evolved toward a sharp tip.

Visualizing anisotropy in the surface oxidation of germanium by wet etching of patterned nanowedges: proof of concept.

We study the anisotropy in surface oxidation for Ge(100) and (110) in HCl/H2O2 solution complemented by synchrotron X-ray photoemission spectroscopy (SXPS) measurements integrated with an in situ etching chamber. Visual anisotropic demonstration is confirmed by lithographic Ge nanowedges.

Ruptured Mycotic Abdominal Aortic Pseudoaneurysm in a Patient on Hemodialysis Complicated with Oxacillin-Resistant Staphylococcus aureus Bacteremia.

Despite a high incidence of Staphylococcus aureus bacteremia in hemodialysis patients, bacterial invasion with aortic wall infection resulting in a pseudoaneurysm rarely occurs. This report describes a case of mycotic pseudoaneurysm of the abdominal aorta that grew rapidly and ruptured into the distal vena cava causing persistent bacteremia in a patient undergoing hemodialysis complicated with oxacillin-resistant S. aureus bacteremia.

Establishing a complex surgical oncology program with low morbidity and mortality at a community hospital.

BACKGROUND: We report our experience with a large volume of complex oncologic resections and describe the framework necessary to develop a program with low morbidity and mortality in a community hospital. METHODS: From August 2010 to May 2014, 224 consecutive patients underwent abdominal oncological resection, at a community hospital by a single surgeon (R.N.B.). Cases included pancreatic, gastric, hepatobiliary, colorectal, hyperthermic intraperitoneal chemotherapy with cytoreduction, splenic, and sarcoma resections. We retrospectively reviewed our prospectively maintained database and evaluated postoperative complications. RESULTS: There was no 0, 30-, 60-, or 90-day mortality. The complication rate was 44%, including 5% grade I, 28% grade II, 9% grade III, and 1% grade IV complications. The median length of stay was 8 days. Mean follow-up for the entire group was 643 days. CONCLUSION: Our study demonstrates that complex oncologic resections can be safely performed in the community setting if a well-organized, surgeon-led multidisciplinary team is assembled.

Electrochemical photodegradation study of semiconductor pigments: influence of environmental parameters.

Chemical transformations in paintings often induce discolorations, disturbing the appearance of the image. For an appropriate conservation of such valuable and irreplaceable heritage objects, it is important to have a good know-how on the degradation processes of the (historical) materials: which pigments have been discolored, what are the responsible processes, and which (environmental) conditions have the highest impact on the pigment degradation and should be mitigated. Pigment degradation is already widely studied, either by analyzing historical samples or by accelerated weathering experiments on dummies. However, in historic samples several processes may have taken place, increasing the complexity of the current state, while aging experiments are time-consuming due to the often extended aging period. An alternative method is proposed for a fast monitoring of degradation processes of semiconductor pigments, using an electrochemical setup mimicking the real environment and allowing the identification of harmful environmental parameters for each pigment. Examples are given for the pigments cadmium yellow (CdS) and vermilion (α-HgS).

Teratogens inducing congenital abdominal wall defects in animal models.

Congenital abdominal wall defects are common anomalies which include gastroschisis, omphalocele and umbilical cord hernia. Recent reports indicate that gastroschisis is increasing in prevalence, whereas omphalocele has remained steady, suggesting that environmental factors may play a part in their pathogenesis. The aim of this study is to review animal teratogen studies resulting in abdominal wall defects to investigate their possible causes. Each report was examined not only for the teratogens causing the defects, but also to carefully identify the defect occurring and its correlation with the known clinical anomalies. We found many discrepancies between the nomenclature used by animal teratology investigators and that used by clinicians. We were able to confirm the induction of gastroschisis by 22 teratogens, omphalocele by 9 teratogens and umbilical cord hernia by 8. There is no doubt that environmental factors may be responsible, at least in part, for all three of the clinical abdominal wall defects. Future studies should take care to appreciate the differences between these anomalies and describe them in detail, so that accurate and meaningful conclusions can be obtained.