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We propose a nonlinear-optics-based nanosensor to detect malachite green (MG) contaminants on semiconductor interfaces such as silicon (Si). Applying the simplified bond hyperpolarizability model (SBHM), we simplified the second-harmonic generation (SHG) analysis of an MG-Si(111) surface and were able to validate our model by reproducing experimental rotational anisotropy (RA) SHG experiments. For the first time, density functional theory (DFT) calculations using ultrasoft pseudopotentials were implemented to obtain the molecular configuration and bond vector orientation required by the SBHM to investigate and predict the second-harmonic generation contribution for an MG-Si 001 surface. We show that the SBHM model significantly reduces the number of independent components in the nonlinear tensor of the MG-Si(111) interface, opening up the possibility for real-time and non-destructive contaminant detection at the nanoscale. In addition, we derive an explicit formula for the SHG far field, demonstrating its applicability for various input polarization angles. Finally, an RASHG signal can be enhanced through a simulated photonic crystal cavity up to 4000 times for more sensitivity of detection. Our work can stimulate more exploration using nonlinear optical methods to detect and analyze surface-bound contaminants, which is beneficial for environmental monitoring, especially for mitigating pollution from textile dyes, and underscores the role of nonlinear optics in real-time ambient-condition applications.

Teleoperation allows workers to safely control powerful construction machines; however, its primary reliance on visual feedback limits the operator's efficiency in situations with stiff contact or poor visibility, hindering its use for assembly of pre-fabricated building components. Reliable, economical, and easy-to-implement haptic feedback could fill this perception gap and facilitate the broader use of robots in construction and other application areas. Thus, we adapted widely available commercial audio equipment to create AiroTouch, a naturalistic haptic feedback system that measures the vibration experienced by each robot tool and enables the operator to feel a scaled version of this vibration in real time. Accurate haptic transmission was achieved by optimizing the positions of the system's off-the-shelf accelerometers and voice-coil actuators. A study was conducted to evaluate how adding this naturalistic type of vibrotactile feedback affects the operator during telerobotic assembly. Thirty participants used a bimanual dexterous teleoperation system (Intuitive da Vinci Si) to build a small rigid structure under three randomly ordered haptic feedback conditions: no vibrations, one-axis vibrations, and summed three-axis vibrations. The results show that users took advantage of both tested versions of the naturalistic haptic feedback after gaining some experience with the task, causing significantly lower vibrations and forces in the second trial. Subjective responses indicate that haptic feedback increased the realism of the interaction and reduced the perceived task duration, task difficulty, and fatigue. As hypothesized, higher haptic feedback gains were chosen by users with larger hands and for the smaller sensed vibrations in the one-axis condition. These results elucidate important details for effective implementation of naturalistic vibrotactile feedback and demonstrate that our accessible audio-based approach could enhance user performance and experience during telerobotic assembly in construction and other application domains., Competing Interests: KK is a co-inventor of a patented older version of the described technology for haptic feedback. The patent is titled “Systems and methods for providing vibration feedback in robotic systems” and was filed in the United States, Europe, and South Korea in 2011 and 2012. These patents have not been licensed to any company. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationship that could be construed as a potential conflict of interest., (Copyright © 2024 Gong, Mat Husin, Erol, Ortenzi and Kuchenbecker.)

Hepatic hydrothorax is a pleural effusion (typically ≥500 mL) that develops in patients with cirrhosis and/or portal hypertension in the absence of other causes. In most cases, hepatic hydrothorax is seen in patients with ascites. However, ascites is not always found at diagnosis and is not clinically detected in 20% of patients with hepatic hydrothorax. Some patients have no symptoms and incidental findings on radiologic examination lead to the diagnosis of the condition. In the majority of cases, the patients present with symptoms such as dyspnea at rest, cough, nausea, and pleuritic chest pain. The diagnosis of hepatic hydrothorax is based on clinical manifestations, radiological features, and thoracocentesis to exclude other etiologies such as infection (parapneumonic effusion, tuberculosis), malignancy (lymphoma, adenocarcinoma) and chylothorax. The management strategy involves a stepwise approach of one or more of the following: Reducing ascitic fluid production, preventing fluid transfer to the pleural space, fluid drainage from the pleural cavity, pleurodesis (obliteration of the pleural cavity), and liver transplantation. The complications of hepatic hydrothorax are associated with significant morbidity and mortality. The complication that causes the highest morbidity and mortality is spontaneous bacterial empyema (also called spontaneous bacterial pleuritis).