Tree-Inspired Aerogel Comprising Nonoxidized Graphene Flakes and Cellulose as Solar Absorber for Efficient Water Generation.

As global freshwater shortages worsen, solar steam generation (SSG) emerges as a promising, eco-friendly, and cost-effective solution for water purification. However, widespread SSG implementation requires efficient photothermal materials and solar evaporators that integrate enhanced light-to-heat conversion, rapid water transportation, and optimal thermal management. This study investigates using nonoxidized graphene flakes (NOGF) with negligible defects as photothermal materials capable of absorbing over 98% of sunlight. By combining NOGF with cellulose nanofibers (CNF) through bidirectional freeze casting, we created a vertically and radially aligned solar evaporator. The hybrid aerogel exhibited exceptional solar absorption, efficient solar-to-thermal conversion, and improved surface wettability. Inspired by tree structures, our design ensures rapid water supply while minimizing heat loss. With low NOGF content (∼10.0%), the NOGF/CNF aerogel achieves a solar steam generation rate of 2.39 kg m-2 h-1 with an energy conversion efficiency of 93.7% under 1-sun illumination, promising applications in seawater desalination and wastewater purification.

Geriatric Nutritional Risk Index and 30-Day Postoperative Mortality in Geriatric Burn Patients.

INTRODUCTION: The geriatric nutritional risk index (GNRI) can easily identify malnutrition-associated morbidity and mortality. We investigated the association between preoperative GNRI and 30-d mortality in geriatric burn patients who underwent surgery. METHODS: The study involved geriatric burn patients (aged ≥ 65 y) who underwent burn surgery between 2012 and 2022. The GNRI was computed using the following formula: 1.489 × serum albumin concentration (mg/L) + 41.7 × patient body weight/ideal body weight. Patients were dichotomized into the high GNRI (≥ 82) and low GNRI (< 82) groups. GNRI was evaluated as an independent predictor of 30-d postoperative mortality. The study also evaluated the association between GNRI and sepsis, the need for continuous renal replacement therapy (CRRT), major adverse cardiac events (MACE), and pneumonia. RESULTS: Out of 270 patients, 128 (47.4%) had low GNRI (< 82). Multivariate Cox regression analysis revealed that low GNRI was significantly associated with 30-d postoperative mortality (hazard ratio: 1.874, 95% confidence interval [CI]: 1.146-3.066, P = 0.001). Kaplan-Meier analysis revealed that the 30-day mortality rate differed significantly between the low and high GNRI groups (log-rank test, P < 0.001). The 30-d postoperative mortality (hazard ratio: 2.677, 95% CI: 1.536-4.667, P < 0.001) and the incidence of sepsis (odds ratio [OR]: 2.137, 95% CI: 1.307-3.494, P = 0.004), need for CRRT (OR: 1.919, 95% CI: 1.101-3.344, P = 0.025), MACE (OR: 1.680, 95% CI: 1.018-2.773, P = 0.043), and pneumonia (OR: 1.678, 95% CI: 1.019-2.764, P = 0.044), were significantly higher in the low GNRI group than in the high GNRI group. CONCLUSIONS: Preoperative low GNRI was associated with increased 30-d postoperative mortality, sepsis, need for CRRT, MACE, and pneumonia in geriatric burn patients.

Boosting Thermal Conductivity by Surface Plasmon Polaritons Propagating along a Thin Ti Film.

We experimentally demonstrate boosted in-plane thermal conduction by surface plasmon polaritons (SPPs) propagating along a thin Ti film on a glass substrate. Due to the lossy nature of metal, SPPs can propagate over centimeter-scale distances even along a supported metal film, and the resulting ballistic heat conduction can be quantitatively validated. Further, for a 100-nm-thick Ti film on a glass substrate, a significant enhancement of in-plane thermal conductivity compared to bulk value (∼25%) is experimentally shown. This Letter will provide a new avenue to employ SPPs for heat dissipation along a supported thin film, which can be readily applied to mitigate hot-spot issues in microelectronics.

Nanomechanical Sensing Using Heater-Integrated Fluidic Resonators.

Micro/nanochannel resonators have been used to measure cells, suspended nanoparticles, or liquids, primarily at or near room temperature while their high temperature operation can offer promising applications such as calorimetric measurements and thermogravimetric analysis. To date, global electrothermal or local photothermal heating mechanisms have been attempted for channel resonators, but both approaches are intrinsically limited by a narrow temperature modulation range, slow heating/cooling, less quantitative heating, or time-consuming optical alignment. Here, we introduce heater-integrated fluidic resonators (HFRs) that enable fast, quantitative, alignment-free, and wide-range temperature modulation and simultaneously offer resistive thermometry and resonant densitometry. HFRs with or without a dispensing nozzle are fabricated, thoroughly characterized, and used for high throughput thermophysical properties measurements, microchannel boiling studies, and atomized spray dispensing. The HFR, without a doubt, opens a new avenue for nanoscale thermal analysis and processing and further encourages the integration of additional functions into channel resonators.

Absorption characteristics of a metal-insulator-metal nanodisk for solar thermal applications.

Due to their ability to confine light in a sub-wavelength scale and achieve coherent absorption, plasmonic nanostructures have been intensively studied for solar energy harvesting. Although nanoparticles generating localized surface plasmon resonance (LSPR) have been thoroughly studied for application in a direct absorption solar collector (DASC), nanoparticles exciting magnetic polaritons (MP) for use in a DASC have not drawn much attention. In this work, we report a metal-insulator-metal (MIM) nanodisk that can excite MP peaks apart from the LSPR in the solar spectrum. It was found that the MIM nanodisk generates a broader and relatively more uniform absorption band compared to a pure metallic nanodisk. The MP peaks were also found to cause less significant scattering compared to those associated with the LSPR. We finally showed that the peaks induced by the MIM nanodisk are highly tunable by varying the particle dimensions, making the proposed MIM nanodisk a potential candidate for solar thermal applications.

Soft and Deformable Sensors Based on Liquid Metals.

Liquid metals are one of the most interesting and promising materials due to their electrical, fluidic, and thermophysical properties. With the aid of their exceptional deformable natures, liquid metals are now considered to be electrically conductive materials for sensors and actuators, major constituent transducers in soft robotics, that can experience and withstand significant levels of mechanical deformation. For the upcoming era of wearable electronics and soft robotics, we would like to offer an up-to-date overview of liquid metal-based soft (thus significantly deformable) sensors mainly but not limited to researchers in relevant fields. This paper will thoroughly highlight and critically review recent literature on design, fabrication, characterization, and application of liquid metal devices and suggest scientific and engineering routes towards liquid metal sensing devices of tomorrow.

Stroke Volume Variation and Stroke Volume Index Can Predict Fluid Responsiveness after Mini-Volume Challenge Test in Patients Undergoing Laparoscopic Cholecystectomy.

Background and Objectives: For using appropriate goal-directed fluid therapy during the surgical conditions of pneumoperitoneum in the reverse Trendelenburg position, we investigated the predictability of various hemodynamic parameters for fluid responsiveness by using a mini-volume challenge test. Materials and Methods: 42 adult patients scheduled for laparoscopic cholecystectomy were enrolled. After general anesthesia was induced, CO2 pneumoperitoneum was applied and the patient was placed in the reverse Trendelenburg position. The mini-volume challenge test was carried out with crystalloid 4 mL/kg over 10 min. Hemodynamic parameters, including stroke volume variation (SVV), cardiac index (CI), stroke volume index (SVI), mean arterial pressure (MAP), and heart rate (HR), were measured before and after the mini-volume challenge test. The positive fluid responsiveness was defined as an increase in stroke volume index ≥10% after the mini-volume challenge. For statistical analysis, a Shapiro-Wilk test was used to test the normality of the data. Continuous variables were compared using an unpaired t-test or the Mann-Whitney rank-sum test. Categorical data were compared using the chi-square test. A receiver operating characteristic curve analysis was used to assess the predictability of fluid responsiveness after the mini-volume challenge. Results: 31 patients were fluid responders. Compared with the MAP and HR, the SVV, CI, and SVI showed good predictability for fluid responsiveness after the mini-volume challenge test (area under the curve was 0.900, 0.833, and 0.909, respectively; all p-values were <0.0001). Conclusions: SVV and SVI effectively predicted fluid responsiveness after the mini-volume challenge test in patients placed under pneumoperitoneum and in the reverse Trendelenburg position.

Face-to-face intubation using a lightwand in a patient with severe thoracolumbar kyphosis: a case report.

BACKGROUND: Severe deformity of the thoracolumbar spine may cause difficulty in airway management during induction of anesthesia. Therefore, special attention must be devoted to patient safety. CASE PRESENTATION: A 65-year-old male with severe thoracolumbar kyphosis was scheduled to undergo posterior spinal fusion under general anesthesia. Due to his inability to lie supine, conventional tracheal intubation under direct laryngoscopy was difficult. Alternatively, face-to-face tracheal intubation using a lightwand in the semi-recumbent position was performed. Intubation was successful on the first attempt without any complications. CONCLUSIONS: The face-to-face intubation technique using a lightwand is one of several alternative techniques for tracheal intubation in patients who cannot lie supine.

Electromagnetic resonance modes on a two-dimensional tandem grating and its application for broadband absorption in the visible spectrum.

In this work, we numerically investigate the electromagnetic resonances on two-dimensional tandem grating structures. The base of a tandem grating consists of an opaque Au substrate, a SiO(2) spacer, and a Au grating (concave type); that is, a well-known fishnet structure forming Au/SiO(2)/Au stack. A convex-type Au grating (i.e., topmost grating) is then attached on top of the base fishnet structure with or without additional SiO(2) spacer, resulting in two types of tandem grating structures. In order to calculate the spectral reflectance and local magnetic field distribution, the finite-difference time-domain method is employed. When the topmost Au grating is directly added onto the base fishnet structure, the surface plasmon and magnetic polariton in the base structure are branched out due to the geometric asymmetry with respect to the SiO(2) spacer. If additional SiO(2) spacer is added between the topmost Au grating and the base fishnet structure, new magnetic resonance modes appear due to coupling between two vertically aligned Au/SiO(2)/Au stacks. With the understanding of multiple electromagnetic resonance modes on the proposed tandem grating structures, we successfully design a broadband absorber made of Au and SiO(2) in the visible spectrum.

Hyperbolic metamaterial-based near-field thermophotovoltaic system for hundreds of nanometer vacuum gap.

Artificially designed hyperbolic metamaterial (HMM) possesses extraordinary electromagnetic features different from those of naturally existing materials. In particular, the dispersion relation of waves existing inside the HMM is hyperbolic rather than elliptical; thus, waves that are evanescent in isotropic media become propagating in the HMM. This characteristic of HMMs opens a novel way to spectrally control the near-field thermal radiation in which evanescent waves in the vacuum gap play a critical role. In this paper, we theoretically investigate the performance of a near-field thermophotovoltaic (TPV) energy conversion system in which a W/SiO2-multilayer-based HMM serves as the emitter at 1000 K and InAs works as the TPV cell at 300 K. By carefully designing the thickness of constituent materials of the HMM emitter, the electric power of the near-field TPV devices can be increased by about 6 times at 100-nm vacuum gap as compared to the case of the plain W emitter. Alternatively, in regards to the electric power generation, HMM emitter at experimentally achievable 100-nm vacuum gap performs equivalently to the plain W emitter at 18-nm vacuum gap. We show that the enhancement mechanism of the HMM emitter is due to the coupled surface plasmon modes at multiple metal-dielectric interfaces inside the HMM emitter. With the minority carrier transport model, the optimal p-n junction depth of the TPV cell has also been determined at various vacuum gaps.

Temperature measurement of Joule heated silicon micro/nanowires using selectively decorated quantum dots.

We developed a novel method to measure local temperature at micro/nano-scale regions using selective deposition of quantum dots (QDs) as a sensitive temperature probe and measured the temperature of Joule heated silicon microwires (SiMWs) and silicon nanowires (SiNWs) by this method. The QDs are selectively coated only on the surface of the SiMWs and SiNWs by a sequential process composed of selective opening of a polymethyl methacrylate layer via Joule heating, covalent bonding of QDs, and lift-off process. The temperatures of the Joule-heated SiMWs and SiNWs can be measured by characterizing the temperature-dependent shift of photoluminescence peak of the selectively deposited QDs even with far-field optics. The validity of the extracted temperature has been also confirmed by comparing with numerical simulation results. The proposed method can potentially provide micro/nanoscale measurement of localized temperatures for a wide range of electrical and optical devices.

Graphene-assisted Si-InSb thermophotovoltaic system for low temperature applications.

The present work theoretically analyzes the performance of the near-field thermophotovoltaic (TPV) energy conversion device for low temperature applications (Tsource ∼ 500 K). In the proposed TPV system, doped Si is employed as the source because its optical property can be readily tuned by changing the doping concentration, and InSb is selected as a TPV cell because of its low bandgap energy (0.17 eV). In order to enhance the near-field thermal radiation between the source and the TPV cell, monolayer of graphene is coated on the cell side so that surface plasmon can play a critical role in heat transfer. It is found that monolayer of graphene can significantly enhance the power throughput by 30 times and the conversion efficiency by 6.1 times compared to the case without graphene layer. The resulting maximum conversion efficiency is 19.4% at 10-nm vacuum gap width.

Single nanowire resistive nano-heater for highly localized thermo-chemical reactions: localized hierarchical heterojunction nanowire growth.

A single nanowire resistive nano-heater (RNH) is fabricated, and it is demonstrated that the RNH can induce highly localized temperature fields, which can trigger highly localized thermo-chemical reactions to grow hierarchical nanowires directly at the desired specific spot such as ZnO nanowire branch growth on a single Ag nanowire.

Optical property of blended plasmonic nanofluid based on gold nanorods.

Present work experimentally characterizes the optical property of blended plasmonic nanofuids based on gold nanorod (AuNR) with different aspect ratios. The existence of localized surface plasmon resonance was verified from measured extinction coefficient of three AuNR solutions, and spectral tunability of AuNR nanofluid was successfully demonstrated in the visible and near-infrared spectral region. The representative aspect ratio and volume fraction of each sample were then calculated from the relation between extinction coefficient and extinction efficiency, which leads to the design of a blended plasmonic nanofluid having broad-band absorption characteristic in the visible and near-infrared spectral region. The results obtained from this study will facilitate the development of a novel volumetric solar thermal collectors using plasmonic nanofluids.

Prognostic impact of beta-2 microglobulin in patients with extranodal natural killer/T cell lymphoma.

Although serum beta-2 microglobulin (B2M) has been suggested as an independent prognostic factor for several lymphoproliferative diseases, it has rarely been investigated in extranodal natural killer/T cell lymphoma (ENKTL). From a prospectively collected database, 145 patients with ENKTL were identified. Among them, a total of 101 patients were included in the analysis, with exclusion of patients without baseline serum B2M level and those did not receive anticancer therapy. Serum B2M (<3.0 vs. ≥3.0 mg/L) was analyzed for association with overall survival (OS). Seventy-nine (78 %) patients had nasal ENKTL, and 22 (22 %) had extranasal ENKTL. In overall patients, median OS was 26.7 months (95 % confidence interval (CI), not assessable), with a median follow-up of 32.4 months (range, 0.9-155.2 months). While median OS was not reached in patients with nasal ENKTL, extranasal ENKTL group had median OS of 5.1 months (95 % CI, 1.2-8.9 months; p < 0.001). Baseline serum B2M was significantly associated with OS in patients with nasal ENKTL (p < 0.001). This was consistent in limited (stages I and II) nasal ENKTL (p = 0.002) and disseminated (stages III and IV) nasal ENKTL (p = 0.02). However, there was no difference of OS in extranasal ENKTL patients (p = 0.69). In multivariate analysis including other prognostic factors, elevated serum B2M was significantly associated with poor OS (hazard ratio (HR) = 3.8, 95 % CI 1.7-8.2, p = 0.001, in a model including Korean Prognostic Index, and HR = 3.6, 95 % CI 1.6-8.2, p = 0.002, in a model including International Prognostic Index). In patients with nasal ENKTL, baseline serum B2M is a powerful prognostic factor. The prognostic value of B2M was independent of previously established prognostic models. Further investigations are necessary to validate the role of B2M in ENKTL.

Age and gender are important considerations in choosing the sniffing position for laryngoscopic view.

AIMS: The sniffing position is considered to be the standard position for direct laryngoscopic viewing. This crossover study evaluated age and gender as variables in comparing the benefits of the sniffing position over simple head extension for laryngeal view during direct laryngoscopy. METHODS: Laryngoscopy with a curved blade was performed on 200 anesthetized adults (100 males, 100 females) presenting for routine elective surgery. Glottic visualization was assessed by using the percentage of glottic opening (POGO) score in both simple extension and sniffing positions without the aid of the assistant or external laryngeal manipulation. Each gender group was divided into a younger group (< 50 years) and an older group (≥ 50 years). POGO scores were compared between both positions within each group. RESULTS: Mean (SD) POGO scores increased significantly only in younger male patients from 43% (39%) in the head extension position to 76% (30%) in the sniffing position. CONCLUSION: The sniffing position seems to be advantageous for getting a better laryngeal view during laryngoscopy for tracheal intubation in adult male patients less than 50 years old.

Reversible Solar Heating and Radiative Cooling Devices via Mechanically Guided Assembly of 3D Macro/Microstructures.

Solar heating and radiative cooling are promising solutions for decreasing global energy consumption because these strategies use the Sun (≈5800 K) as a heating source and outer space (≈3 K) as a cooling source. Although high-performance thermal management can be achieved using these eco-friendly methods, they are limited by daily temperature fluctuations and seasonal changes because of single-mode actuation. Herein, reversible solar heating and radiative cooling devices formed via the mechanically guided assembly of 3D architectures are demonstrated. The fabricated devices exhibit the following properties: i) The devices reversibly change between solar heating and radiative cooling under uniaxial strain, called dual-mode actuation. ii) The 3D platforms in the devices can use rigid/soft materials for functional layers owing to the optimized designs. iii) The devices can be used for dual-mode thermal management on a macro/microscale. The devices use black paint-coated polyimide (PI) films as solar absorbers with multilayered films comprising thin layers of polydimethylsiloxane/silver/PI, achieving heating and cooling temperatures of 59.5 and -11.9 °C, respectively. Moreover, mode changes according to the angle of the 3D structures are demonstrated and the heating/cooling performance with skin, glass, steel, aluminum, copper, and PI substrates is investigated.

High rates of detection of respiratory viruses in the nasal washes and mucosae of patients with chronic rhinosinusitis.

Respiratory viral infections are often implicated as triggers of chronic rhinosinusitis (CRS) flare-ups. However, there is a paucity of respiratory viral surveillance studies in CRS patients, and such studies could elucidate the potential role of viruses in promoting symptoms and aggravating mucosal inflammation. Therefore, a prospective case-control study was conducted to determine the prevalence of respiratory viruses in CRS patients and non-CRS controls. Nasal lavage fluids and turbinate epithelial cells were collected prospectively from 111 CRS patients and 50 controls. Multiplex PCR was used to identify common respiratory viruses in both sample types and the infection rate was compared between groups. Respiratory viruses were detected in 50.5% of lavage samples and in 64.0% of scraping samples from CRS patients. The overall infection rate was significantly different in CRS patients and controls (odds ratio, 2.9 in lavage and 4.1 in scraping samples). Multiple viral infections were detected more frequently in lavage samples from CRS patients than those from controls (P < 0.01; odds ratio, 7.7). Rhinovirus was the most prevalent virus and the only virus with a significantly different infection rate in CRS patients and controls in both samples (odds ratio, 3.2 in lavage and 3.4 in scraping samples). This study detected a higher prevalence of respiratory viruses in CRS patients than controls, suggesting that there may be significant associations between inflammation of CRS and respiratory viruses, particularly rhinovirus. Further studies should investigate the exact role of highly prevalent respiratory viruses in CRS patients during symptomatic aggravation and ongoing mucosal inflammation.

Near-field thermal radiation between graphene-covered doped silicon plates.

The present work describes a theoretical investigation of the near-field thermal radiation between doped Si plates coated with a mono-layer of graphene. It is found that the radiative heat flux between doped Si plates can be either enhanced or suppressed by introducing graphene layer, depending on the Si doping concentration and chemical potential of graphene. Graphene can enhance the heat flux if it matches resonance frequencies of surface plasmon at vacuum-source and vacuum-receiver interfaces. In particular, significant enhancement is achieved when graphene is coated on both surfaces that originally does not support the surface plasmon resonance. The results obtained in this study provide an important guideline into enhancing the near-field thermal radiation between doped Si plates by introducing graphene.