Wavelength Tunability of Ion-bombardment Induced Ripples on Sapphire

A study of ripple formation on sapphire surfaces by 300-2000 eV Ar+ ion bombardment is presented. Surface characterization by in-situ synchrotron grazing incidence small angle x-ray scattering and ex-situ atomic force microscopy is performed in order to study the wavelength of ripples formed on sapphire (0001) surfaces. We find that the wavelength can be varied over a remarkably wide range-nearly two orders of magnitude-by changing the ion incidence angle. Within the linear theory regime, the ion induced viscous flow smoothing mechanism explains the general trends of the ripple wavelength at low temperature and incidence angles larger than 30. In this model, relaxation is confined to a few-nm thick damaged surface layer. The behavior at high temperature suggests relaxation by surface diffusion. However, strong smoothing is inferred from the observed ripple wavelength near normal incidence, which is not consistent with either surface diffusion or viscous flow relaxation.Comment: Revtex4, 19 pages, 10 figures with JPEG forma

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Neuraminidase produces a decrease of adherence of slime-forming Staphylococcus aureus to gelatin-impregnated polyester fiber graft fabric: An experimental study

Because slime-forming microorganisms are the major causative agents of graft infections, we aimed to investigate bacterial adherence in slime-forming and nonslime-forming Staphylococcus aureus and to determine the role of neuraminidase (NANase) on adherence to gelatin-impregnated polyester fiber graft fabric. An in vitro model was developed to quantitatively measure bacterial adherence to the surface of the graft. The grafts were divided into two groups - those colonized with slime-forming S. aureus and those colonized with nonslime-forming S. aureus. The grafts were put into sterile tubes and human plasma was instilled and incubated at 37°C to perform fibrin deposition on the grafts. After 48 h of incubation, grafts were drained and inoculated with slime-forming or nonslime-forming S. aureus in triptic soy broth in the presence or absence of NANase. Following 36 h of incubation at 36°C, grafts were vortexed and cultured to perform a colony count. Bacterial counts were expressed as total colony-forming units per square centimeter of graft. Slime-forming S. aureus had greater affinity with the graft compared with nonslime-forming S. aureus (P 0.05). These results show that slime plays an important role in the pathogenesis of vascular graft infection. Adherence of slime-forming S. aureus can be decreased by NANase treatment. This may have implications for the development of neuraminidase-embedded vascular grafts to diminish biomaterial-related infections. © 2007 The Japanese Society for Artificial Organs

Continuous renal replacement therapy after cardiac surgery in patients with acute renal failure

Aim Acute renal failure is an important adverse effect of cardiopulmonary bypass that can result in high mortality or morbidity rates. It can be treated with continuous renal replacement therapy after cardiac surgery. The purpose of this study was to determine the factors associated with the mortality and incidence of acute renal failure in patients of post cardiac surgery. Methods Patients (1564) who underwent cardiac surgery between January 2007 and January 2012 and treated with continuous renal replacement therapy were included (N=40). Patients with previous renal disorders were excluded. A retrospective analysis was carried out. Results Overall, continuous renal replacement therapy was used in 40 (2.6%) patients. The mean age was 62.7±11 years. Mean duration of cardiopulmonary bypass was 166±80 min, and aorta cross-clamping time was 97±35 min. The patients' mean pretherapy creatinine level and mean creatinine level before hospital discharge were 3.3±1.1 mg/dL and 1.1±0.4 mg/dl, respectively. Thirty-day mortality was 35%. Only 6 patients required long-term renal replacement therapy. Conclusion Acute renal failure requiring hemodialysis after cardiac surgery is associated with higher mortality and morbidity and prolonged hospital stay. Early renal recovery with continuous renal replacement therapy seems to offer an evident survival benefit. Continuous renal replacement therapy may represent an important therapy and reduce mortality rates. We believe that these rates might decrease even more with detailed preoperative evaluation and meticulous postoperative care with collaborative management

Hepatitis A seroprevalence and contributing factors in the sixth year medical faculty students

AIM: Susceptibility to hepatitis A infection is shifting to older ages due to the improvements in the economic and environmental conditions, and increasing in the level of education. However, the severity of the disease increases with age. The aim of this study was to examine hepatitis A seroprevalance and contributing factors in the 6th year medical faculty students in Pamukkale University. METHODS: This cross-sectional study was conducted on the 6th year medical faculty students at Pamukkale University in October 2012. 44 students (91.6%) participated in the study. Data is evaluated by descriptive statistics, and either the Pearson Chi-square or the Fisher's test was used to determine the statistical differences between categorical variables. RESULTS: The mean age of the students was 23.7 ± 1.6, and 59.1% of students (n = 26) were women. 12 serum samples (27.3%) were positive for anti-HAV IgG. Fathers' education and the longest lived area identified as independent factors affecting anti-HAV seropositivity. CONCLUSION: As health care personnel, the 6th year medical students are at risk. Either at the beginning of medical education or before clinical training, students should be screened for hepatitis A and catch up immunization programs should be initiated