Incidence and risk factors for recurrence of ampullary adenomas after endoscopic papillectomy: Comparative analysis of familial adenomatous polyposis and sporadic ampullary adenomas in an international multicenter cohort.

OBJECTIVES: Endoscopic papillectomy (EP) is a minimally invasive therapy for the management of ampullary adenomas (AA). We conducted this multicenter study to assess the incidence of and factors related to the recurrence of AA after EP in patients with familial adenomatous polyposis (FAP) compared to sporadic AA. METHODS: We included patients who underwent EP for AA at 10 tertiary hospitals. Adenomatous tissue at the resection site at the time of surveillance endoscopies was considered recurrent disease. RESULTS: In all, 257 patients, 100 (38.9%) with FAP and 157 (61%) patients with sporadic AA, were included. Over a median of 31 (range, 11-61) months, recurrence occurred in 48/100 (48%) of patients with FAP and 58/157 (36.9%) with sporadic AA (P = 0.07). Two (2%) FAP patients and 10 (6.3%) patients with sporadic AA underwent surgery for recurrence. On multivariable regression analysis, the recurrence in FAP was higher than in sporadic patients after the first year of follow-up. AA size (hazard ratio [HR] 1.03, 95% confidence interval [CI] 1.001, 1.056), periampullary extension (HR 2.5, 95% CI 1.5, 4.01), and biliary duct dilation (HR 2.04, 95% CI 1.2, 3.4) increased the risk, while en bloc resection (HR 0.6, 95% CI 0.41, 0.9) decreased the risk of recurrence. CONCLUSION: Recurrence rates are high after EP. Most recurrences in sporadic patients occur within the first year of follow-up, but after the first year of follow-up in patients with FAP. Recurrences are higher with larger adenomas, biliary duct dilation, and periampullary extensions, and may be mitigated by en bloc resection. These factors should be considered in decision-making with the patients.

Esophageal Endoscopic Submucosal Dissection in Older Patients Is Safe and Feasible: A Retrospective Single-Center Cohort Study in the United States.

BACKGROUND: Endoscopic submucosal dissection (ESD) is a well-established method for treating early esophageal carcinomas. However, data on the safety and efficacy of esophageal ESD in older patients in the United States are limited. METHODS: This retrospective study investigated the outcomes of esophageal ESD in patients aged ≥80 years and included those who underwent esophageal ESD between June 2018 and April 2023 at a single center in the United States. Patients were divided into two age groups for comparison: ≥80 and <80 years. Treatment outcomes and complications were evaluated and compared between these groups. RESULTS: A total of 53 cases of esophageal ESD for malignant neoplasms were included, with 12 patients in the ≥80 years age group. No significant differences were observed in the patients' background and characteristics, except for a prior history of interventions (p = 0.04). The en bloc resection rate was 100% in both groups. The R0 resection rate was lower in the ≥80 years age group (75% vs. 88%). There were no complications requiring additional intervention in the ≥80 years age group, such as post-ESD bleeding, perforation, mediastinal emphysema, or pneumonia. CONCLUSIONS: Esophageal ESD may be a safe and feasible procedure for treating esophageal carcinomas in older patients.

Safety of Duodenal Endoscopic Submucosal Dissection for Superficial Non-Ampullary Duodenal Epithelial Tumor: A Single-Center Study in the United States.

Endoscopic submucosal dissection (ESD) of superficial non-ampullary duodenal epithelial tumors (SNADETs) is associated with a high rate of en bloc resection and low rate of recurrence. However, in the United States, SNADETs are predominantly managed using endoscopic mucosal resection (EMR) or surgery because the feasibility and safety of duodenal ESD have not yet been established. In this study, we analyzed the outcomes of duodenal ESD for SNADETs. This single-center retrospective study reviewed the data of patients who underwent ESD for SNADETs between June 2018 and August 2023. Baseline patient characteristics, histopathology of the resected lesions, adverse events, and recurrence rates were evaluated. The primary outcome measures were en bloc resection, complications, and recurrence rate. Thirty ESD procedures were performed on 24 patients. All 30 lesions were adenomas, with no cancerous lesions. The en bloc resection rate and R0 resection rates were both 53%. There were no cases of procedure-associated perforation. Post-ESD bleeding was observed in six cases. No ESD-related mortality was observed. The recurrence rate was 14% in 1 year follow up, and 28% the during all follow-up period. ESD is a safe option for SNADET in the United States; however further comparative studies are necessary to determine the optimal procedure for North American populations.

Artificial fast-adapting mechanoreceptor based on carbon nanotube percolating network.

Most biological sensors preferentially encode changes in a stimulus rather than the steady components. However, intrinsically phasic artificial mechanoreceptors have not yet been described. We constructed a phasic mechanoreceptor by encapsulating carbon nanotube film in a viscoelastic matrix supported by a rigid substrate. When stimulated by a spherical indenter the sensor response resembled the response of fast-adapting mammalian mechanoreceptors. We modelled these sensors from the properties of percolating conductive networks combined with nonlinear contact mechanics and discussed the implications of this finding.

pH driven addressing of silicon nanowires onto Si3N4/SiO2 micro-patterned surfaces.

pH was used as the main driving parameter for specifically immobilizing silicon nanowires onto Si3N4 microsquares at the surface of a SiO2 substrate. Different pH values of the coating aqueous solution enabled to experimentally distribute nanowires between silicon nitride and silicon dioxide: at pH 3 nanowires were mainly anchored on Si3N4; they were evenly distributed between SiO2 and Si3N4 at pH 2.8; and they were mainly anchored on SiO2 at pH 2. A theoretical model based on DLVO theory and surface protonation/deprotonation equilibria was used to study how, in adequate pH conditions, Si nanowires could be anchored onto specific regions of a patterned Si3N4/SiO2 surface. Instead of using capillary forces, or hydrophilic/hydrophobic contrast between the two types of materials, the specificity of immobilization could rely on surface electric charge contrasts between Si3N4 and SiO2. This simple and generic method could be used for addressing a large diversity of nano-objects onto patterned substrates.

Integrated electrically driven surface plasmon resonance device for biosensing applications.

Compact and portable surface plasmon resonance (SPR) biosensors of high sensitivities can be made through integration of discrete components in a single device. We report on a device comprising a vertical cavity light emitting diode (VLED) integrated with gold-based biosensing nanostructures fabricated atop its surface. Coupling of surface plasmon waves was achieved by the introduction of a spacer SiO2 layer located between the light source and the functionalized Au thin film. The SPR signal was extracted in far field with a Au-based nanograting and detected using a custom designed hyperspectral imager. We discuss the performance of a VLED-based SPR device employed for detection of different concentration saltwater solutions.

Framework for the analysis of nanotechnologies' impacts and ethical acceptability: basis of an interdisciplinary approach to assessing novel technologies.

The genetically manipulated organism (GMO) crisis demonstrated that technological development based solely on the law of the marketplace and State protection against serious risks to health and safety is no longer a warrant of ethical acceptability. In the first part of our paper, we critique the implicitly individualist social-acceptance model for State regulation of technology and recommend an interdisciplinary approach for comprehensive analysis of the impacts and ethical acceptability of technologies. In the second part, we present a framework for the analysis of impacts and acceptability, devised-with the goal of supporting the development of specific nanotechnological applications-by a team of researchers from various disciplines. At the conceptual level, this analytic framework is intended to make explicit those various operations required in preparing a judgement about the acceptability of technologies that have been implicit in the classical analysis of toxicological risk. On a practical level, we present a reflective tool that makes it possible to take into account all the dimensions involved and understand the reasons invoked in determining impacts, assessing them, and arriving at a judgement about acceptability.

Transcranial direct current stimulation accelerates allocentric target detection.

BACKGROUND: Previous research on hemispatial neglect has provided evidence for dissociable mechanisms for egocentric and allocentric processing. Although a few studies have examined whether tDCS to posterior parietal cortex can be beneficial for attentional processing in neurologically intact individuals, none have examined the potential effect of tDCS on allocentric and/or egocentric processing. OBJECTIVE/HYPOTHESIS: Our objective was to examine whether transcranial direct current stimulation (tDCS), a noninvasive brain stimulation technique that can increase (anodal) or decrease (cathodal) cortical activity, can affect visuospatial processing in an allocentric and/or egocentric frame of reference. METHODS: We tested healthy individuals on a target detection task in which the target--a circle with a gap--was either to the right or left of the viewer (egocentric), or contained a gap on the right or left side of the circle (allocentric). Individuals performed the task before, during, and after tDCS to the posterior parietal cortex in one of three stimulation conditions--right anodal/left cathodal, right cathodal/left anodal, and sham. RESULTS: We found an allocentric hemispatial effect both during and after tDCS, such that right anodal/left cathodal tDCS resulted in faster reaction times for detecting stimuli with left-sided gaps compared to right-sided gaps. CONCLUSIONS: Our study suggests that right anodal/left cathodal tDCS has a facilitatory effect on allocentric visuospatial processing, and might be useful as a therapeutic technique for individuals suffering from allocentric neglect.

Plasmonic propagations distances for interferometric surface plasmon resonance biosensing.

A surface plasmon resonance (SPR) scheme is proposed in which the local phase modulations of the coupled plasmons can interfere and yield phase-sensitive intensity modulations in the measured signal. The result is an increased traceability of the SPR shifts for biosensing applications. The main system limitation is the propagation distance of the coupled plasmon modes. This aspect is therefore studied for thin film microstructures operating in the visible and near-infrared spectral regions. The surface roughness of the substrate layer is examined for different dielectrics and deposition methods. The Au layer, on which the plasmonic modes are propagating and the biosensing occurs, is also examined. The surface roughness and dielectric values for various deposition rates of very thin Au films are measured. We also investigate an interferometric SPR setup where, due to the power flux transfer between plasmon modes, the specific choice of grating coupler can either decrease or increase the plasmon propagation length.

Carbon nanotubes (CNTs) based strain sensors for a wearable monitoring and biofeedback system for pressure ulcer prevention and rehabilitation.

This paper presents an overview of the functioning principles of CNTs and their electrical and mechanical properties when used as strain sensors and describes a system embodiment for a wearable monitoring and biofeedback platform for use in pressure ulcer prevention and rehabilitation. Two type of CNTs films (multi-layered CNTs film vs purified film) were characterized electrically and mechanically for potential use as source material. The loosely woven CNTs film (multi-layered) showed substantial less sensitivity than the purified CNTs film but had an almost linear response to stress and better mechanical properties. CNTs have the potential to achieve a much higher sensitivity to strain than other piezoresistors based on regular of conductive particles such as commercially available resistive inks and could become an innovative source material for wearable strain sensors. We are currently continuing the characterization of CNTs based strain sensors and exploring their use in a design for 3-axis strain sensors.

Hyperspectral imaging of diffracted surface plasmons.

We present the results of far field measurements of the complete 3D dispersion relation of a surface plasmon resonance (SPR) effect induced by an integrated quantum well nanodevice. The light modulations in the far field, where the surface plasmons are extracted by a grating, has been calculated for a continuum of energies and wavevectors injected by the luminescent substrate. We introduce a novel experimental method for direct mapping of the EM wave dispersion that enables the monitoring of massive amounts of light-scattering related information. The quasi-real time method is applied for tracking, in the E(k) space, the SPR peak surfaces generated by the investigated nanodevice. Those additional dimensions, measured with scalable tracking precision, reveal anisotropic surficial interactions and provide spectroscopic response for SPR.

The impact of charging on low-energy electron beam lithography.

A major issue in low voltage lithography is surface charging, which results in beam deflection presented as uneven exposure between adjacent structures. In this study, charge-induced pattern distortions in low-voltage energy beam lithography (LVEBL) were investigated using a silicide direct-write electron beam lithography process. Two methodologies have been proposed to avert charging effects in LVEBL, namely, pattern randomizing and lithography using the crossover voltage. Experimental results demonstrated that these methods are effective in significantly reducing the problems associated with charging. They indicate that charging on a sample is a function of time interval and proximity between line structures. In addition, the optimum time and distance between exposures for no charge-induced pattern distortion were determined. By using the crossover voltage of the material for lithography, charging effect can be significantly minimized.