Small Diameter Research Articles

Adoption of self-exothermic reaction for synthesis of multifunctional carbon quantum dots: Applications to vincristine sensing and cell imaging

This work introduces an extremely easy method for preparing luminescent carbon dots (CDs) at ambient temperature using 1,2-naphthoquinone sulphonate and ethylenediamine as precursors via self-exothermic reaction without energy input. The as-obtained CDs have a high quantum yield (34.1 %), a production yield of 21.2 %, and a small size diameter (3.44 nm). Various techniques (NMR, TEM, EDX-mapping, XPS, XRD, FT-IR, fluorescence, and UV–visible spectroscopy) were used to characterize the prepared CDs. The CDs exhibited an excitation-independent emission with λex of 275 nm, demonstrating their homogeneity and high purity. The anticancer drug vincristine (VCR) quantitively quenched the fluorescent signal of the synthesized CDs, allowing their application as the first fluorescent nano-sensor to determine VCR. The quenching effect was linear within the range of 0.2–5.0 μg mL−1, enabling the determination of VCR in vials, plasma, and for content uniformity testing with a detection limit of 0.06 μg mL−1. Moreover, the synthesized CDs were employed as a bio-sensing platform to detect VCR in cancer cells owing to their good selectivity, excellent biocompatibility, minimal cytotoxicity, and high stability. The fabrication of CDs with excellent properties at room temperature under mild conditions paves the way for new advancements in the room temperature synthesis of CDs and offers a highly efficient alternative to traditional synthesis approaches.

Understanding the Size‐Dependent Photostability and Photoluminescence Intermittency of Blue‐Emitting Core/Graded Alloy/Shell “giant”‐Quantum Dots

AbstractRecently, giant quantum dots (g‐QDs) with a core/interface graded alloy shell/shell structure have shown promise in reducing photoluminescence (PL) intermittency and improving photostability. However, this approach has been mainly demonstrated with red and green emitting g‐QDs but the blue‐emitting graded alloy QDs has remained less explored. To tackle this challenge, a composition gradient method is employed to create three blue‐emitting CdZnS/CdxZn1–xS/ZnS core/interface graded alloy shell/shell (C/A/S) quantum dots (QDs) with different diameters. The sample with the largest diameter (gQD‐3) exhibits superior optical characteristics, with a photoluminescence quantum yield (PLQY) of approximately 62% and around 80% ON/radiative events at the single‐particle level. Conversely, the smallest diameter (gQD‐1) sample shows lower PLQY and only 30% radiative events with longer OFF/nonradiative events. Probability distribution analysis of PL trajectories, fitted with a truncated power law, reveals a significantly higher carrier de‐trapping rate in gQD‐3 compared to gQD‐1, attributed to its proximity to band edge trap states. Additionally, the largest diameter sample retains remarkable optical performance during 48 h of continuous UV irradiation in colloidal suspension and single‐particle levels. These findings show optimized core/shell structures, gradual alloy interfaces, and outer shell coatings can stabilize blue‐emitting quantum dots, advancing next‐gen optoelectronics.

Optimization of mechanical properties of small diameter artificial blood vessels based on alginate/chitosan/gelatin

Due to the rise in cardiovascular disease and the problem of autologous transplant limitation, the emergence of 3D bioprinted blood vessels using natural polymer materials as ink is becoming increasingly important in the field of small-diameter artificial blood vessels (φ ≤ 6 mm). In this paper, gelatin was firstly adopted to explore alginate/chitosan composite hydrogel properties and solve the current issues of poor mechanical performance and suboptimal printability of small-diameter blood vessels, which indicated that the modification caused a 17.7 % increase in compressive strength and a 63.2 % enhancement in tensile properties. The material microstructure evaluation showed that the samples with gelatin(4 %) presented the excellent water absorption rate(>90 %) significantly increasing their porosities. A self-developed 3D bioprinter was utilized to clarify the controllable mechanism of small-diameter artificial blood vessel, which has superior performance and excellent printability. This study provides a new reference solution to the current challenges in the bio-ink performance and printability of small-diameter artificial blood vessels.

Fabrication of 3D Bioactive Melt Electrowriting Composite Scaffold with High Osteogenic Potential

A key challenge in using melt electrowriting (MEW) technology is incorporating large amounts of bioactive inorganic materials, such as hydroxyapatite (HA). In the present study, following optimization of the fabrication parameters, 40%-HA (HA40) nanoparticles were pre-mixed into medical-grade polycaprolactone (PCL) and processed using the MEW (MEW) technique to mimic the structure and function of the natural extracellular matrix (ECM) for bone regeneration. The HA40 fibrous composite scaffolds showed continuous writing and obtained a well-connected and orderly stacked fibre with a small diameter size (67 ± 8.5µm). A major result of the present study was the successful enrichment and accumulation of the HA particles, which mostly occurred on the MEW fibre external surfaces. This design allows for direct interfacial interaction with human periodontal ligament cells (hPDLCs). We systematically investigated the behaviour and function of hPDLCs on the HA40 composite scaffold, alongside parameters related to mineralization. The HA40 scaffold demonstrated significantly higher metabolic activity and enhanced expression of osteonectin and RUNX2 compared to PCL-only scaffolds, as well as increased levels of ALP and COL1. The study’s findings demonstrate that bioactive composite scaffolds, incorporating 40% HA into m-PCL via MEW, effectively enhance the biological response of the ECM and are promising for potential applications in bone regeneration.

Structure-Mechanical Property Relationships in Carbon Nanotube Yarns

Carbon nanotube (CNT) is an innovative material with significant potential for a wide range of applications, including but not limited to the development of lightweight composite materials or superconductors. A single CNT demonstrates an exceptional degree of tensile strength. CNTs are commonly employed in a structure of yarn, wherein several CNT strands are arranged and aligned together. CNT yarns, on the other hand, have a lower tensile strength than individual CNTs due to the different parameters of the yarn. This study aimed to investigate the effect of different structural parameters on the mechanical properties of CNT yarn. Sixty CNT yarn models with different structures were simulated with the molecular dynamic (MD) simulation. The varied parameters are the chirality of the CNTs, CNTs’ inner diameter, number of walls, crosslink density, and yarn twist angle. Tensile strength results from the simulations were compared concerning the varied parameters, and their influence on the nominal tensile strength of the CNT yarn was studied. It was found that the parameters for the CNT yarn that yields a higher tensile strength are the armchair type CNT with a small diameter, a large number of walls, crosslink density higher than approximately 1%, and a low twist angle.

Experimental study on the influence factors of falling film heat transfer characteristics outside different types of horizontal tubes

An experimental setup was established to analyze the performance of a spiral wound heat exchanger applied to natural gas liquefaction. The boiling behavior of subcooled flow over a small diameter, non-round, horizontal tube was investigated using n-pentane as the working fluid. The effects of flow rate, heat flux, fluid inlet temperature and tube spacing on heat transfer performance were investigated. Based on the experimental conditions of this study, the results indicate that: (1) raising the Reynolds number can effectively enhance the heat transfer coefficient; (2) the increasing in heat flux also has a positive impact on heat transfer performance, but the extent of which is related to the Reynolds number; (3) increasing the tube spacing resulted in higher heat transfer coefficients; (4) under the same working conditions, the heat transfer performance of non-round tubes is higher than that of round tubes; (5) correlation equations were developed to calculate the Nu for smooth, round, elliptical, and egg-shaped tubes. The predictions made by these correlation equations deviated by less than 10 % from the experimental results for the entirety of the experimental conditions.

Comparative experimental and numerical study of mixing efficiency in 3D-printed microfluidic droplet generators: T junction, cross junction, and asymmetric junctions with varying angles

In droplet-based microfluidics, rapid mixing during droplet formation enhances reaction uniformity, eliminating the need for micromixers. In this research, we conducted a comprehensive study by first employing a series of two-dimensional (2D) numerical simulations, followed by experimental investigations using 3D-printed microfluidic chips. We compared the mixing efficiency, droplet diameter, and droplet eccentricity of three different types of droplet generators: T junction, cross junction, and asymmetric droplet generators with various angles. Regarding mixing efficiency, we observed that the asymmetric droplet generators outperformed the cross junction by 30 % but fell slightly short of the mixing efficiency achieved by the T junction (1 %). Additionally, while the mixing index in the asymmetric generators closely matched that of the T junction, these asymmetric generators produced smaller droplets by 72 %. Increasing the angle in asymmetric droplet generators resulted in enhanced mixing efficiencies and an increase in droplet diameters. The asymmetric junction with a 30° angle could achieve a mixing efficiency of up to 80 %. Additionally, an analysis of the dispersed phase flow rate revealed that higher flow rates lead to larger droplet sizes and reduced mixing efficiencies. The asymmetric droplet generators improve mixing efficiency facilitating rapid reagent mixing, all while maintaining a small droplet diameter.

A multi-objective method for large multi-lane roundabout design through microscopic traffic simulation and SSAM analysis

Urban traffic congestion poses a significant challenge, impacting both economic efficiency and environmental sustainability. Roundabouts, recognized for their ability to improve traffic flow and reduce collisions, have become a focal point in traffic management strategies in urban areas. Different types and sizes of single and multi-lane roundabouts can be used, including conventional and innovative roundabouts with small, medium or large size diameters. Many optimization models are available for designing conventional roundabouts but not large roundabouts. To partially cover this gap, the present paper introduces a novel approach integrating simulation-based analysis with a goal programming method to optimize large roundabout design. By leveraging advanced traffic simulation tools like AIMSUN Next and Surrogate Safety Assessment Models (SSAMs), this methodology evaluates multiple design scenarios to enhance traffic flow, safety, and environmental performance. A case study of a complex large roundabout in the Italian greenest and sustainable city demonstrates the efficacy of this methodological approach. The findings provide valuable insights for traffic and highway engineers, emphasizing a data-driven, holistic approach to sustainable traffic management and roundabout optimization.

Latest Findings on the Effects of Gold Nanoparticles on the Storage Quality of Blood Products (2011-2022) - A Narrative Review

Abstract: A wide range of challenges are faced during the storage of blood products, including storage lesions, contamination that must be removed, and cell and protein damage due to chemicals and UV exposure. The enhancement of stability exhibited by gold nanoparticles (GNPs) is a notable advantage of these nanoparticles for the storage of blood products. The results of our review of articles from 2011 to 2022 discussing the effect of GNPs on blood products revealed that in RBCs, the dose, concentration, amount, and surface charge of GNPs significantly affect their compatibility. Purified GNPs were compatible with RBCs. Negatively charged GNPs with smaller diameters at lower concentrations were more compatible. However, in the plasma product, the nanoparticle surface modification with different agents showed greater compatibility. PEGylated nanospheres and GNPs exhibited higher albumin conformational stability than those coated with cetyltrimethylammonium bromide and rods. In the platelet product, smaller GNPs and high GNP concentrations induce platelet aggregation. PEGylation increased the platelet compatibility of GNP. The combination of GNPs with human fibrinogen and clopidogrel prevented clot formation. Finally, the findings of this investigation demonstrate that GNPs are contingent on their surface charge, dosage, and concentration.

Slow depolarizing electrical stimuli reveal differential time courses of nociceptor recovery after prolonged topical capsaicin in human skin

AbstractBackgroundWe examined de‐functionalization and temporal functional recovery of C‐nociceptor evoked pain after topical 8% capsaicin applied for 4 consecutive days.MethodsCapsaicin and placebo patches were applied to human forearm skin (n = 14). Cold, warmth and heat pain thresholds, pain NRS to electrical and thermal (48°C, 5 s) stimuli and axon reflex flare were recorded weekly for 49 days. Mechanical and heat sensitive (‘polymodal’) nociceptors were activated by single electrical half‐period sinusoidal pulses (0.5 s, 1 Hz). Mechanical and heat insensitive (‘silent’) nociceptors were activated by 4 Hz sinusoidal stimuli.ResultsCapsaicin abolished heat pain. Sensation to electrical sinusoidal stimulation was reduced but never abolished during the treatment. Pain to electrical 1 Hz ‘polymodal’ nociceptor stimulation took longer to recover than pain ratings to 4 Hz 2.5 s sinusoidal stimulation activating ‘polymodal’ and ‘silent’ nociceptors (35 vs. 21 days). Heat pain was indifferent to placebo from day 21–49. Axon reflex flare was abolished during capsaicin and only recovered to ~50% even after 49 days.ConclusionsCapsaicin abolishes heat transduction at terminal nociceptive endings, whereas small‐diameter axons sensitive to sinusoidal electrical stimulation can still be activated. 1 Hz depolarizing stimuli evoke burst discharges, as demonstrated before, and recover slower after capsaicin than single pulses induced by 4 Hz. The difference in recovery suggests differential time course of functional regeneration for C‐nociceptor sub‐types after capsaicin. All sensations recovered completely within 7 weeks in healthy subjects. Our findings contrast analgesia lasting for months in spontaneous neuropathic pain patients treated with 8% capsaicin.SignificanceSinusoidal electrical stimulation can still activate small diameter axons desensitized to heat after 4 consecutive days of topical 8% capsaicin application and reveals differential temporal functional regeneration of C‐nociceptor sub‐types. Electrical sinusoidal stimulation may detect such axons that no longer respond to heat stimuli in neuropathic skin.

Design and Experimentation of Small Potato Harvester for Heavy Soil in Hilly and Mountainous Areas

At present, the potato’s mechanized harvesting rate in hilly and mountainous areas is very low. The reasons for this are that in heavy soil, the separation of potato rhizomes from soil or vines is not sufficient, harvesting machinery is seriously damaged by the potato epidermis, and the harvested potato is easily buried in soil, resulting in a missed harvest. In this paper, a two-stage cleaning potato harvester with wave-type and roller-group-type separating mechanisms was designed, and its overall structure and working principle are introduced in detail. The new cleaning mechanism can increase the effective separating length and effective contact area of the potato–soil mixture so as to achieve the purpose of removing clay and heavy soil. The main separator uses a structure that combines offset waves with opposite waves and a staggered arrangement of large–small diameter straight bars. The secondary separator adopts a device combining left-hand and right-hand separating rollers. The discrete element model of the whole machine was established, and the results of the theoretical analysis were verified by simulation. The key factors affecting the harvest quality were analyzed by variance analysis and response surface analysis, and the field experiment was carried out with the rate of clean potatoes, damaged potatoes, and peeled potatoes harvested as the indexes. The field experiments showed that the machine achieved a rate of photos on or out of the earth of 98.87%, a damaged potato rate of 0.91%, and a peeled potato rate of 1.13%. The research results provide theoretical support and a technical reference for the design and optimization of potato harvesters, as well as the improvement of the potato–soil separating efficiency and harvest quality.

Annular two-phase flow in a small diameter tube: OpenFOAM simulations with turbulence damping vs optical measurements

In this work, numerical simulations are performed to predict two-phase annular flow of refrigerant R245fa inside a 3.4 mm diameter vertical channel. The VOF (Volume of Fluid) method implemented in an OpenFOAM solver is used to accurately track the vapor-liquid interface. A 2D axisymmetric domain is considered and the Adaptive Mesh Refinement (AMR) method is applied to the cells near the liquid/vapor interface. The Reynolds-Averaged Navier Stokes (RANS) equations are solved and the k-ω SST model is adopted for turbulence modelling in both the liquid and vapor phase. Simulations are used to calculate instantaneous and mean values of the liquid film thickness at mass flux G = 100 kg m-2 s-1 and vapor quality ranging between 0.2 and 0.85. Numerical results are compared against measurements of the liquid film thickness taken during vertical annular downflow. Previous works from the literature and the deviations observed between present numerical and experimental results suggest the need for turbulence damping at the vapor-liquid interface by adding a source term in the ω equation. The simulations show that a low value of the turbulence damping parameter (e.g. 1) causes the average liquid film thickness to increase by 25 %–52 % compared to the non-damped scenario. The interface presents large amplitude disturbance waves in the non-damped case, whereas small ripple waves are predicted when turbulence damping is introduced. Furthermore, the difference between the application of a symmetric and asymmetric treatment for the source term is analysed. From the comparison between experimental data and numerical simulations, it emerges that the value of the correct damping source term to be applied is strictly dependent on the vapor quality.

Comparison of ultrasound assisted and intraoperative diameter measurement in acute appendicitis.

Detailed anamnesis and systematic physical examination are often relevant in the diagnostic routine of acute appendicitis. However, physicians are increasingly motivated to obtain radiological approval. Inherent limitations due to radiologists' experience and the presenting anatomy may result in contradictory outcomes between the described and intraoperative findings. In this study, a comparison of anthropometric measurements of the appendix vermiformis obtained by radiologists and surgeons in children with acute appendicitis is discussed. The external appendiceal diameter in 53 patients who underwent surgery between April 2022 and January 2024 was measured at three different anatomical locations during preoperative ultrasound and intraoperatively with the help of Vernier calipers. Appendectomy materials were classified into negative, acute, and complicated appendicitis subgroups on the basis of histopathological results. The widest median diameter, expressed in millimeters, was analyzed statistically in terms of diagnostic accuracy. Histopathological analysis revealed negative appendectomy in 15.1%, acute appendicitis in 66%, and complicated appendicitis in 18.8% of the patients. The median age at presentation was 11.4 years (4-17.3 years), and 45.3% of the patients were females. The average median appendiceal diameter was 7.8 ± 2.4 mm according to the caliper and 7.9 ± 2.7 mm according to ultrasound (p > 0.05). The evaluation by the caliper revealed a much smaller diameter in 19 patients than did ultrasound. The appendiceal diameter of eight documented negative appendectomy samples was 7 mm or greater. US failed to identify the presence of an appendicolith in 11 cases (20.8%), all of which were disclosed during histopathological evaluation. It is possible to conclude that ultrasound and intraoperative anthropometric measurements correlate according to our study. Diagnostic accuracy, however, which is individually based on ultrasound appendix diameter values greater than 6 mm, is controversial. It is clear that comparison and further reinterpretation of such anthropometric measurements in light of histopathological consequences may help diminish the frequency of negative and perforated appendectomies.

Facile synthesis of spherical-shaped CeC2–TiO2 nanocomposite electrocatalyst with boosted alkaline OER

Developing noble metal-free multifunctional electrocatalysts to catalyze water oxidation is vital for future renewable energy systems. Herein, through several defect modifications, the CeC2–TiO2 nanocomposite on the strength of enriched oxygen vacancies was successfully fabricated by facile hydrothermal method on SS (stainless steel) substrate, attributed to the conductive ability for fast electron transportation. A well-defined phase growth, vibrational bonding of metal atoms, morphological determination, and elemental composition for synthesized heterostructured electrocatalysts were revealed by XRD, FTIR, TEM, and EDX, respectively. XPS has complied to understand the moderate binding energies of CeC2–TiO2 for OER intermediates, which signifies the strong interactions between electronic states of Ce, C, Ti, and O atoms. With the plentiful catalytic active sites, the resultant CeC2–TiO2 entails low overpotentials of only 169 mV and 108.8 mV/dec Tafel slope to afford 10 mA cm−2 for OER in 1.0 M KOH are tested through cyclic and linear sweep voltammogram measurements, thereby exhibit promising activity in alkaline water electrolysis. EIS measurements revealed a decreased polarization resistance for the composite dominated by the small semicircle diameter, corresponding to the adsorption of intermediates. Finally, observed results strongly recommended that the CeC2–TiO2 catalyst exhibited superior OER performance due to excellent electrical chemical coupling between CeC2 and TiO2.

Utilizing an aspheric lens and compound ellipsoidal cavity for a laser uniform illumination system

To achieve uniform laser illumination of an active imaging system with a small aperture diameter and large field angle, we have developed what we believe to be a novel structure for achieving uniform beam shaping that integrates a laser source, an aspheric lens, and a composite ellipsoidal cavity to enable active laser illumination. Through an aspheric lens, the fundamental mode Gaussian beam is transformed into double Gaussian and flat-top radiation at the target plane. The double Gaussian radiation is further reflected by a complex ellipsoidal cavity, where it is evenly distributed into equal radiation flux. This flux combines with the flat-top radiation, resulting in a uniform distribution at the target plane. The parameters of the complex ellipsoidal cavity are determined using an equalization algorithm. After combining the transmission for flat-top shaping by the aspheric lens and secondary reflection shaping by the composite ellipsoidal cavity, we achieved an aperture measuring 29.7 mm with an aperture angle of 84.0°, at a distance of 2 m from the target plane, with a diameter of 3.6 m, resulting in uniformity reaching 92.7%. RMS and MT/R determine the effectiveness of the compound ellipsoidal cavity design, depending on the maximum reflection angle and transmission angle. MT/R is inversely proportional to the maximum reflection angle, while RMS is directly proportional to the transmission angle. By setting the maximum reflection angle to 32.0° and the transmission angle to 8.0°, we were able to achieve a minimum root-mean-square focusing radius of 108.6 µm along with a minimum effective MT/R ratio of 1.07. The overlap degree between transmission and reflection directly impacts the target plane’s uniformity, adjusted through a defined adjustment factor. Optimizing this factor to 0.9 maximizes the uniformity of the target plane.

Axillary artery access considerations in Impella 5.5insertion: Insights from exclusive axillary approach forsuccessful support.

The Impella 5.5® is commonly inserted via the axillary artery (AX) in patients with cardiogenic shock. The right AX has traditionally been preferred to avoid crossing the aortic arch, and a minimum diameter of 7 mm has been recommended to accommodate the device (21 Fr). There is limited data on choice of laterality of access and AX size required, both in terms of technicality of the procedure as well as outcomes. We performed a single-center retrospective cohort analysis of patients who underwent Impella 5.5® implantation between December 2020 and February 2024 (N = 75). Data including demographics and outcomes were stratified both by diameter (small, <7 mm vs. normal, ≥7 mm) and laterality of access (right vs. left). Adverse events included stroke, limb ischemia, procedural bleeding or infection, and unplanned explant due to complications. Delivery time was defined as time from advancing the first wire to activation of the device. AX approach was attempted in all (N = 74) but one requiring innominate access, with a technical success rate of 95.9% (N = 71/74). The mean age was 58.8 ± 13.3 years, with 81.1% males. The median delivery time was 7.0 (25th, 75th percentiles: 4.0, 11.5) min with a median support duration of 13 (7.7, 24) days. Ten patients (13.5%) had a small AX, with a mean diameter of 6.3 ± 0.5 mm and were more likely to be younger compared to the normal AX group. Fifty-nine patients (79.7%) had insertion via the right AX. Median delivery time was comparable across all groups (small, 5.4 [3.5, 10.9] vs. normal, 7 [4.0, 12.1] min, p = 0.59) and (right, 10.4 [5.3, 15.2] vs. left, 6 [3.7, 10.4] min, p = 0.35). There was no difference between the rates of stroke, ischemia, bleeding, or infection when comparing by size or laterality. Survival to discharge was 59.5%, with 21.1% mortality on support, all in patients with a normal AX diameter, but with no difference between right versus left. In our study, laterality and a small diameter of AX access did not affect outcomes of Impella 5.5®, with a similar safety profile.

How is tree growth rate linked to root functional traits in phylogenetically related poplar hybrids?

Fine roots play a crucial role in soil nutrient and water acquisition, significantly contributing to tree growth. Fine roots with a high specific root length (SRL) and small diameter are often considered to help trees grow fast. However, inconsistencies in the literature do not provide a clear basis on the effect of root functional traits, such as SRL or root mass density (RMD), on tree growth rate in phylogenetically related trees. Our aim was to examine relationships between tree growth rate and root functional traits, using clones displaying different growth rates in a hybrid poplar plantation located in New Liskeard, ON, Canada. Fine roots (diameter<2mm) samples were collected using soil cores at depths of 0-20, 20-40 and 40-60cm, and analyzed for morphological, chemical and architectural traits. High SRL and thin fine roots were associated with the least productive clones, which is not consistent with the root economics spectrum (RES) theory. However, the most productive clone had larger fine root diameter and higher root lignin concentrations, probably reducing root construction and maintenance costs and carbon losses. Therefore, at the 0-20 and 20-40cm depths, tree growth rates showed positive correlations with root diameter and root lignin concentrations, but negative correlations with SRL and root soluble compounds concentration. Increasing RMD at the 0-20cm depth promoted tree growth rates, showing the importance of soil exploration in the topsoil for tree growth. We conclude that fine root variation does not always follow the RES hypothesis and argue that the rapid growth rate of trees may also be driven by fine root growth in diameter and mass in phylogenetically related trees.

Controlling the thiourea for optimized growth of CdS nanorod arrays for improved photoelectrochemical water splitting

Energy and the environment are very important issues to secure, preserve and improve our modern lifestyle. The conversion of sunlight into hydrogen and oxygen via photoelectrochemical (PEC) water splitting is one of the most potential routes for clean energy. Cadmium sulfide (CdS) is a promising semiconductor for utilization as a photoanode. In this work, CdS has been grown via the hydrothermal method by optimizing the thiourea concentration. The growth of CdS with equal concentration of Cd2+ and S2-demonstrates the crowded hexagonal-shaped nanorod arrays with small diameter and relatively longer length, and it exhibits the highest photocurrent density due to some factors, such as high length-to-diameter ratio, large reaction area, suitable flat band potential, slow charge recombination rate, fast charge transfer, suitable conduction and valence band edges, and surface reaction kinetics. This work will be of potential to further develop improved nanocomposites of CdS nanorods for hydrogen production and research in related fields.

Super-Microsurgery for Vessels with Diameters Smaller Than 0.5 mm.

Introduction: Among super-microsurgical techniques, the anastomosis of vessels smaller than 0.5 mm is very difficult to perform due to the small diameter and thinness of the blood and lymphatic vessel walls. In this article, we report on the main points of super microsurgery, particularly on the anastomosis of veins and lymphatic vessels with diameters smaller than 0.5 mm. Methods and Results: Details of anastomosis of vessels smaller than 0.5 mm. (1) The outer wall of the first blood vessel near the abrupt end hook with the tip of the needle in the needle holder. The entire abrupt end of the first blood vessel was supported by forceps in the surgeon's left-hand. (2) The surgeon decided the entry point and angle of the needle while moving the tip. After the needle was fixed, a force was applied so that the needle could pass through to the vascular wall. (3) After the needle passed through, the tip was confirmed to be located in the lumen of the first blood vessel. (4) The tip of the needle was inserted into the lumen of the second blood vessel, and the bite was adjusted while touching the second blood vessel through the endometrium. (5) Once the tip was properly positioned, counter-traction was applied by holding the entire outer wall with a left-hand forceps. (6) The needle was held near the tip and pulled out along its curvature. The anastomosis time was 11.35 minutes on average (9 to 14 minutes). The patency rate for all 20 anastomosis procedures was also 100%. Conclusion: The important points of LVA for lymphatic vessels and veins smaller than 0.5 mm were reported. Once the surgeons are familiarized with this anastomosis procedure, they can typically perform one anastomosis in about 10 minutes.

Ultrahigh Extinction Ratio Leaky-Guided Hollow Core Fiber Mach-Zehnder Interferometer Assisted by a Large Core Hollow Fiber Beam Splitter.

We proposed a novel fiber Mach-Zehnder interferometer (FMZI) that can perform an ultrahigh extinction ratio (ER), ultracompact, and ultra-broadband interference characteristics. The FMZI structure is based on an extremely tiny hollow core fiber (HCF) with a small diameter of 10 μm (named HCF10) connected with a beam splitter of a large core of 50 μm HCF (named HCF50). The refractive index (RI) of the air core is lower than that of the HCF cladding; a leaky-guided fiber waveguide (LGFW) occurs in such a short-section HCF10 waveguide to simultaneously have the core and cladding modes. To achieve better fringe visibility of the interference, the section of HCF50 assists in splitting the optical light into core and cladding beams launched into the HCF10 with appropriate intensities. Experimental and simulation results show that the optical characteristics of the proposed LGFW-FMZI are very similar. Based on the results of the study, the length of the HCF10 primarily influences the free spectral range (FSR) of the interference spectra, and the HCF50 splitter significantly controls the optimal extinction ratio (ER) of the interference fringes. By exactly adjusting the lengths of HCF10 and HCF50, the proposed fiber interferometers can perform the capability of an ultrahigh ER over 50 dB with the arbitrary FSR in the transmitted interference spectra over an ultra-broad wavelength range of 1250 nm to 1650 nm.