Micro-textured films for reducing microbial colonization in a clinical setting.

BACKGROUND: Transmission of microbes in the hospital environment occurs frequently through human interactions with high-touch surfaces such as patient beds and over-bed tables. Although stringent cleaning routines are implemented as a preventive measure to minimize transmission of microbes, it is desirable to have high-touch surfaces made of antimicrobial materials. Physical texturing of solid surfaces offers a non-bactericidal approach to control the colonization of such surfaces by microbes. AIM: To investigate the efficacy of micro-textured polycarbonate films in reducing bacterial load on over-bed tables in a hospital ward. METHODS: Two different micro-patterns were fabricated on polycarbonate film via a thermal imprinting method. Micro-textured films were then mounted on patient over-bed tables in a general hospital ward and the bacterial load monitored over 24 h. Total colony counts, which represented on-specific bacterial loading, and meticillin-resistant Staphylococcus aureus counts were monitored at each time-point. FINDINGS: Over a period of 24 h, both micro-textured surfaces showed consistently lower bacterial load as compared to the unpatterned polycarbonate and the bare over-bed table laminate. This study supports the findings of earlier laboratory-scale studies that microscale physical texturing can reduce bacterial colonization on a solid surface. CONCLUSION: Results of the current study suggest that micro-textured surfaces could provide a viable method for reducing microbial contamination of high-touch surfaces in hospitals.

Barrett's esophagus: Ten years of experience at a tertiary care hospital center in Mexico. / Esófago de Barrett: experiencia de 10 años en un centro de tercer nivel en México.

INTRODUCTION: The prevalence of Barrett's esophagus has been calculated at between 1.3 and 1.6%. There is little information with respect to this in Mexico. AIM: To determine the frequency and characteristics of Barrett's esophagus in patients that underwent endoscopy at a national referral center, within a 10-year time frame. MATERIAL AND METHODS: The databases of the pathology and gastrointestinal endoscopy departments of the Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán" were analyzed, covering the period of January 2002 to December 2012. Patients with a histologic diagnosis of Barrett's esophagus were included. The variables of age, sex, the presence of dysplasia/esophageal adenocarcinoma, Barrett's esophagus length, and follow-up were analyzed. RESULTS: Of 43,639 upper gastrointestinal endoscopies performed, 420 revealed Barrett's esophagus, corresponding to a frequency of 9.6 patients for every 1,000 endoscopies. Of those patients, 66.9% (n=281) were men, mean patient age±SD was 57.2±15.3 years, 223 patients (53%) presented with long-segment Barrett's esophagus, and 197 (47%) with short-segment Barrett's esophagus. Dysplasia was not present in 339 patients (80.7%). Eighty-one (19.3%) patients had some grade of dysplasia or cancer: 48/420 (11.42%) presented with low-grade dysplasia, 20/420 (4.76%) with high-grade dysplasia, and 13/420 (3.1%) were diagnosed with esophageal cancer arising from Barrett's esophagus. Mean follow-up time was 5.6 years. CONCLUSIONS: The frequency of Barrett's esophagus was 9.6 cases for every 1,000 upper gastrointestinal endoscopies performed. Dysplasia was not documented in the majority of the patients with Barrett's esophagus and they had no histopathologic changes during follow-up. A total of 19.3% of the patients presented with dysplasia or cancer.

One-dimensional extended lines of divacancy defects in graphene.

Since the outstanding transport properties of graphene originate from its specific structure, modification at the atomic level of the graphene lattice is needed in order to change its electronic properties. Thus, topological defects play an important role in graphene and related structures. In this work, one-dimensional (1D) arrangement of topological defects in graphene are investigated within a density functional theory framework. These 1D extended lines of pentagons, heptagons and octagons are found to arise either from the reconstruction of divacancies, or from the epitaxial growth of graphene. The energetic stability and the electronic structure of different ideal extended lines of defects are calculated using a first-principles approach. Ab initio scanning tunneling microscopy (STM) images are predicted and compared to recent experiments on epitaxial graphene. Finally, local density of states and quantum transport calculations reveal that these extended lines of defects behave as quasi-1D metallic wires, suggesting their possible role as reactive tracks to anchor molecules or atoms for chemical or sensing applications.

Controlling edge morphology in graphene layers using electron irradiation: from sharp atomic edges to coalesced layers forming loops.

Recent experimental reports indicate that Joule heating can atomically sharpen the edges of chemical vapor deposition grown graphitic nanoribbons. The absence or presence of loops between adjacent layers in the annealed materials is the topic of a growing debate that this Letter aims to put to rest. We offer a rationale explaining why loops do form if Joule heating is used alone, and why adjacent nanoribbon layers do not coalesce when Joule heating is applied after high-energy electrons first irradiate the sample. Our work, based on large-scale quantum molecular dynamics and electronic-transport calculations, shows that vacancies on adjacent graphene sheets, created by electron irradiation, inhibit the formation of edge loops.

Metallic and ferromagnetic edges in molybdenum disulfide nanoribbons.

The magnetic and electronic properties of MoS(2) nanoribbons with zigzag and armchair edges are investigated using LSDA-DFT. We found that the properties of the nanoribbons are very different from bulk MoS(2) due to edge states. Armchair nanoribbons could be metallic and exhibit a magnetic moment; however, when passivating with hydrogen, they become semiconducting. Zigzag nanoribbons are metallic and exhibit unusual magnetic properties regardless of passivation. Our results could explain the recent evidence of ferromagnetism in flat MoS(2) clusters, and motivate the synthesis of novel MoS(2) nanosystems.