Comparison of blood loss between intra-articular microporous polysaccharide hemospheres powder and tranexamic acid following primary total knee arthroplasty.

Total knee arthroplasty (TKA) is associated with substantial blood loss and tranexamic acid (TXA) effectively reduces postoperative bleeding. Although it is known that there is no difference between intravenous or intra-articular (IA) injection, the general interest is directed towards topical hemostatic agents regarding thromboembolic events in high-risk patients. This study aimed to compare the blood conservation effects of IA MPH powder and TXA in patients undergoing primary TKA. We retrospectively analyzed 103 patients who underwent primary TKA between June 2020 and December 2021. MPH powder was applied to the IA space before capsule closure (MPH group, n = 51). TXA (3 g) was injected via the drain after wound closure (TXA group, n = 52). All patients underwent drain clamping for three postoperative hours. The primary outcome was the drain output, and the secondary outcomes were the postoperative hemoglobin (Hb) levels during the hospitalization period and the perioperative blood transfusion rates. An independent Student's t-test was used to determine differences between the two groups. The drain output in the first 24 h after surgery was significantly higher in the MPH group than in the TXA group. The postoperative Hb levels were significantly lower in the MPH group than in the TXA group. In patients with simultaneous bilateral TKA, there was a significant difference in the blood transfusion volumes and the rates between groups. It is considered that IA MPH powder cannot replace IA TXA because of an inferior efficacy in reducing blood loss and maintaining postoperative Hb levels in the early postoperative period after primary TKA. Moreover, in the case of simultaneous bilateral TKA, we do not recommend the use of IA MPH powder because it was notably less effective in the field of transfusion volume and rate.

Treatment of intractable septic ankle arthritis with a continuous closed irrigation system.

OBJECTIVES: The study aimed to evaluate the efficacy of a continuous closed irrigation system (CCIS) after open debridement for patients with intractable septic ankle arthritis. PATIENTS AND METHODS: The retrospective study analyzed the intractable septic arthritis of 12 (6 males, 6 females; mean age: 64.1±14.7 years; range, 33 to 80 years) patients managed by CCIS between July 2015 and July 2020. All patients had previously undergone operations to treat septic ankle arthritis without resolution of the infection. After open debridement, the CCIS was usually equipped with two outflow tubes and one inflow tube. Saline inflow was about 1 L per day. RESULTS: The mean follow-up period was 30.8±14.9 (range, 15 to 70) months. The CCIS was maintained for a mean of 5.1±2.1 (range, 3 to 7) days. The mean number of operations the patients had previously undergone was 2.83±1.5 (range, 1 to 6). For 11 (91.6%) out of 12 patients, infection did not recur after one-time CCIS, and laboratory test results remained normal. Six patients had previously undergone total ankle replacement arthroplasty. These patients underwent antibiotics-mixed cement arthroplasty after CCIS. For five of six with infected total ankle replacement arthroplasty, infection did not recur after CCIS. However, one patient without the removal of both implants experienced recurrence at the same site after four postoperative months. In the reoperation, after the removal of both implants and the application of antibiotics-mixed cement arthroplasty, the infection was cleared. CONCLUSION: Use of CCIS after open debridement for intractable septic ankle arthritis is a good treatment option since it is relatively simple and safe, with good results.

Epidermis-Inspired Wearable Piezoresistive Pressure Sensors Using Reduced Graphene Oxide Self-Wrapped Copper Nanowire Networks.

Wearable piezoresistive sensors are being developed as electronic skins (E-skin) for broad applications in human physiological monitoring and soft robotics. Tactile sensors with sufficient sensitivities, durability, and large dynamic ranges are required to replicate this critical component of the somatosensory system. Multiple micro/nanostructures, materials, and sensing modalities have been reported to address this need. However, a trade-off arises between device performance and device complexity. Inspired by the microstructure of the spinosum at the dermo epidermal junction in skin, a low-cost, scalable, and high-performance piezoresistive sensor is developed with high sensitivity (0.144 kPa-1 ), extensive sensing range ( 0.1-15 kPa), fast response time (less than 150 ms), and excellent long-term stability (over 1000 cycles). Furthermore, the piezoresistive functionality of the device is realized via a flexible transparent electrode (FTE) using a highly stable reduced graphene oxide self-wrapped copper nanowire network. The developed nanowire-based spinosum microstructured FTEs are amenable to wearable electronics applications.

6 nm super-resolution optical transmission and scattering spectroscopic imaging of carbon nanotubes using a nanometer-scale white light source.

Optical transmission and scattering spectroscopic microscopy at the visible and adjacent wavelengths denote one of the most informative and inclusive characterization methods in material research. Unfortunately, restricted by the diffraction limit of light, it cannot resolve the nanoscale variation in light absorption and scattering, diagnostics of the local inhomogeneity in material structure and properties. Moreover, a large quantity of nanomaterials has anisotropic optical properties that are appealing yet hard to characterize through conventional optical methods. There is an increasing demand to extend the optical hyperspectral imaging into the nanometer length scale. In this work, we report a super-resolution hyperspectral imaging technique that uses a nanoscale white light source generated by superfocusing the light from a tungsten-halogen lamp to simultaneously obtain optical transmission and scattering spectroscopic images. A 6-nm spatial resolution in the visible to near-infrared wavelength regime (415-980 nm) is demonstrated on an individual single-walled carbon nanotube (SW-CNT). Both the longitudinal and transverse optical electronic transitions are measured, and the SW-CNT chiral indices can be identified. The band structure modulation in a SW-CNT through strain engineering is mapped.

Nanoengineering Approaches Toward Artificial Nose.

Significant scientific efforts have been made to mimic and potentially supersede the mammalian nose using artificial noses based on arrays of individual cross-sensitive gas sensors over the past couple decades. To this end, thousands of research articles have been published regarding the design of gas sensor arrays to function as artificial noses. Nanoengineered materials possessing high surface area for enhanced reaction kinetics and uniquely tunable optical, electronic, and optoelectronic properties have been extensively used as gas sensing materials in single gas sensors and sensor arrays. Therefore, nanoengineered materials address some of the shortcomings in sensitivity and selectivity inherent in microscale and macroscale materials for chemical sensors. In this article, the fundamental gas sensing mechanisms are briefly reviewed for each material class and sensing modality (electrical, optical, optoelectronic), followed by a survey and review of the various strategies for engineering or functionalizing these nanomaterials to improve their gas sensing selectivity, sensitivity and other measures of gas sensing performance. Specifically, one major focus of this review is on nanoscale materials and nanoengineering approaches for semiconducting metal oxides, transition metal dichalcogenides, carbonaceous nanomaterials, conducting polymers, and others as used in single gas sensors or sensor arrays for electrical sensing modality. Additionally, this review discusses the various nano-enabled techniques and materials of optical gas detection modality, including photonic crystals, surface plasmonic sensing, and nanoscale waveguides. Strategies for improving or tuning the sensitivity and selectivity of materials toward different gases are given priority due to the importance of having cross-sensitivity and selectivity toward various analytes in designing an effective artificial nose. Furthermore, optoelectrical sensing, which has to date not served as a common sensing modality, is also reviewed to highlight potential research directions. We close with some perspective on the future development of artificial noses which utilize optical and electrical sensing modalities, with additional focus on the less researched optoelectronic sensing modality.

Synthesis of gold nanostructures using glycine as the reducing agent.

Biological synthesis of gold nanostructures could potentially offer an environmentally friendly alternative to traditional chemical synthetic methods. During the last decades, various biomolecules, including amino acids, have been successfully used as reducing and capping agents to synthesize multi-shaped gold nanostructures. A grand challenge in this field is to increase our ability to control the size and shape of gold nanostructures formed precisely by systematic synthetic approaches based on the understanding of the mechanism for structural determination. In this study, using glycine as the model amino acid and chloroaurate (AuCl4 -) ions as the precursor solution, we report the finding that the shape of the gold nanostructures synthesized showed a strong correlation with the speciation of gold complexes determined by the pH, precursor concentration and chloride concentration of the solvent system. The gold chloro-hydroxy speciation [AuClx(OH)4-x]- (with x = 0-4) influenced the shape of the gold nanostructures formed, with gold nanoplatelets, nanotriangles, nanokites and nanoribbons observed at x = 4, 3, 2 and 1, respectively, and spherical nanoparticles observed at x = 0. Glycine was found to play a role as a reducing agent, but no significant effect on the morphology was observed, indicating the dominance of gold chloro-hydroxy speciation in the structural formation. These results collectively provide synthetic considerations to systematically synthesize non-spherical to spherical biosynthesized gold nanostructures by controlling the speciation of [AuClx(OH)4-x]-.

Utilization of a magnetic field-driven microscopic motion for piezoelectric energy harvesting.

In spite of the recent advances in the development of high performing piezoelectric materials, their applications are typically limited to the direct conversion of mechanical impact energy to electrical energy, potentially risking mechanical failures. In this study, we developed piezoelectric poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)) nanofibers integrated with SiO2-shelled Fe3O4 magnetic nanoparticles, to utilize magnetic energy to reliably drive the piezoelectric effect. Specifically, we show that the shape of the magnetic nanoparticles exerts a significant effect on the efficiency of the magneto-mechano-electrical energy conversion as magnetic nanorods exhibit approximately 70% enhancement in electric field generation under cyclic magnetic fields as compared to nanospheres. Under an alternating magnetic field of 200 mT, the magnetic nanorod-piezoelectric nanofiber composite generated a peak-to-peak voltage of approximately 30 mVp-p with a superior durability without any performance degradation after over 1 million cycles. This study demonstrates the potential of magnetic-field responsive, piezoelectric-based materials in energy harvesting applications from non-mechanical energy sources.

Ultra-sharp and surfactant-free silver nanowire for scanning tunneling microscopy and tip-enhanced Raman spectroscopy.

Chemically-synthesized single-crystalline silver nanowire (AgNW) probes can combine the scanning tunneling microscopy (STM) technique with tip-enhanced Raman scattering spectroscopy (TERS) for complementary morphological and chemical information with nanoscale spatial resolution. However, its performance has been limited by the blunt nanowire tip geometry, the insulating surfactant layer coating AgNW surfaces, and the thermal-induced mechanical vibrations. Here, we report a reproducible fabrication method for the preparation of sharp-tip AgNW-based TERS probes. By removing the polyvinylpyrrolidone (PVP) surfactant molecules from the AgNW surfaces for stable electrical conductivity and controlling the protruding length with µm-level accuracy for improved mechanical stability, we demonstrate atomic-resolution STM imaging with the sharp-tip AgNW probe. Furthermore, the sharp-tip AgNW has an excellent TER enhancement (∼1.1 × 106), which is about 66 folds of that achieved by regular AgNWs. Our experiments demonstrate that AgNWs with clean interfaces and the proper tip geometry can provide reliable and reproducible STM and TER characterizations, which remove the hurdles preventing the implementation of AgNW in STM-based near-field optical applications for a broad community.

Toward High-Contrast Atomic Force Microscopy-Tip-Enhanced Raman Spectroscopy Imaging: Nanoantenna-Mediated Remote-Excitation on Sharp-Tip Silver Nanowire Probes.

The tip-enhanced Raman spectroscopy (TERS) imaging technique is designed to provide correlated morphological and chemical information with a nanoscale spatial resolution by utilizing the plasmonic resonance supported by metallic nanostructures at the tip apex of a scanning probe. However, limited by the scattering cross sections of these nanostructures, only a small fraction of the incident light can be coupled to the plasmonic resonance to generate Raman signals. The uncoupled light then directly excites background spectra with a diffraction-limited resolution, which becomes the background noise that often blurs the TERS image. Here, we demonstrate how this problem can be solved by physically separating the light excitation region from the Raman signal generation region on the scanning probe. The remote-excitation TERS (RE-TERS) probe, which can be fabricated with a facile, robust and reproducible method, utilizes silver nanoparticles as nanoantennas to mediate the coupling of free-space excitation light to propagating surface plasmon polaritons (SPPs) in a sharp-tip silver nanowire to excite Raman signals remotely. With this RE-TERS probe, a 10 nm spatial resolution was demonstrated on a single-walled carbon nanotube sample, and the strain distribution in a monolayer molybdenum disulfide (MoS2) was mapped.

Capillary-Force-Assisted Clean-Stamp Transfer of Two-Dimensional Materials.

A simple and clean method of transferring two-dimensional (2D) materials plays a critical role in the fabrication of 2D electronics, particularly the heterostructure devices based on the artificial vertical stacking of various 2D crystals. Currently, clean transfer techniques rely on sacrificial layers or bulky crystal flakes (e.g., hexagonal boron nitride) to pick up the 2D materials. Here, we develop a capillary-force-assisted clean-stamp technique that uses a thin layer of evaporative liquid (e.g., water) as an instant glue to increase the adhesion energy between 2D crystals and polydimethylsiloxane (PDMS) for the pick-up step. After the liquid evaporates, the adhesion energy decreases, and the 2D crystal can be released. The thin liquid layer is condensed to the PDMS surface from its vapor phase, which ensures the low contamination level on the 2D materials and largely remains their chemical and electrical properties. Using this method, we prepared graphene-based transistors with low charge-neutral concentration (3 × 1010 cm-2) and high carrier mobility (up to 48 820 cm2 V-1 s-1 at room temperature) and heterostructure optoelectronics with high operation speed. Finally, a capillary-force model is developed to explain the experiment.

Sharp-Tip Silver Nanowires Mounted on Cantilevers for High-Aspect-Ratio High-Resolution Imaging.

Despite many efforts to fabricate high-aspect-ratio atomic force microscopy (HAR-AFM) probes for high-fidelity, high-resolution topographical imaging of three-dimensional (3D) nanostructured surfaces, current HAR probes still suffer from unsatisfactory performance, low wear-resistivity, and extravagant prices. The primary objective of this work is to demonstrate a novel design of a high-resolution (HR) HAR AFM probe, which is fabricated through a reliable, cost-efficient benchtop process to precisely implant a single ultrasharp metallic nanowire on a standard AFM cantilever probe. The force-displacement curve indicated that the HAR-HR probe is robust against buckling and bending up to 150 nN. The probes were tested on polymer trenches, showing a much better image fidelity when compared with standard silicon tips. The lateral resolution, when scanning a rough metal thin film and single-walled carbon nanotubes (SW-CNTs), was found to be better than 8 nm. Finally, stable imaging quality in tapping mode was demonstrated for at least 15 continuous scans indicating high resistance to wear. These results demonstrate a reliable benchtop fabrication technique toward metallic HAR-HR AFM probes with performance parallel or exceeding that of commercial HAR probes, yet at a fraction of their cost.

Effect of Substrate Temperature on Ti/TiO2 Layers Growth Using a Combined Sputtering/Sol-Gel Combustion Method.

A combined radio frequency sputtering/sol-gel combustion method was investigated in order to obtain optimum process condition for fabrication of a Titanium (Ti)/Titanium oxide (TiO2) films electrode of transparent conductive oxide-less dye-sensitized solar cells (TCO-less DSCs), Experimentally, the substrate temperature was changed from R.T. to 500 °C, and it was found that there existed an optimum value for efficient performance of the cell. The porous Ti layer with low sheet resistance (-2.5 Ω/sq.) can be prepared by substrate temperature 250 °C under RF power 300 W and Ar 8 mTorr. The efficiency (η) of the cell was 6.52% [FF: 0.76, VOC: 0.72 V, JSC: 11.91 mA/cm2].

The importance of gender on coronary artery size: in-vivo assessment by intravascular ultrasound.

BACKGROUND: It remains controversial whether women have smaller coronary arteries than men because of a gender-specific trait, or whether the observed differences are primarily due to a difference in body size. Intravascular ultrasound (IVUS), with its ability to provide unique coronary images that allow precise measurement of arterial size in vivo, is ideally suited to address this issue. HYPOTHESIS: Female gender, independent of body size, is associated with smaller coronary artery size as measured by intracoronary ultrasound. METHODS: Intravascular ultrasound images of normal left main arteries were identified retrospectively from a single center database. Associations between demographic and clinical characteristics (including body size) and left main coronary dimensions were assessed with univariant and multivariate regression analyses. RESULTS: We identified 257 completely normal left main arteries. Mean left main arterial areas were smaller in women than in men (17.2 vs. 20.6 mm2, p < 0.001), as were mean luminal areas (14.0 vs. 16.7 mm2, p < 0.001). By multiple regression analysis, the independent predictors of left main lumen were body surface area (p < 0.001) and gender (p = 0. 003). CONCLUSIONS: Body surface area and gender are both independent predictors of coronary artery size, although body size has a greater influence than gender.