Small Diameter Research Articles

Top-Down Phenomenon Observed in the Outer Rainbands of Typhoon Maysak (2020): Insights from the Comparative Analysis of Cloud and Precipitation Microphysics with a Typical Precipitation Event in Northeast China

Abstract Cloud and precipitation microphysics in tropical cyclones (TCs) moving toward Northeast China may exhibit significant distinctions compared with the typical precipitation of this region. In this study, observations from ground-based particle size velocity (Parsivel) disdrometers in Liaoning Province, China, and cloud property data from the Himawari geostationary satellite were utilized to analyze the raindrop size distribution (DSD) characteristics and cloud vertical evolution associated with the outer rainbands of Typhoon Maysak (2020). A comparative analysis was conducted with a typical precipitation event in Northeast China induced by a cold vortex (cold-core low). Our findings reveal distinctive DSD characteristics related to the TC, where medium-sized raindrops dominate, with a smaller diameter but higher concentration in the TC case compared to the typical cold-vortex-induced precipitation case in Northeast China. Convective precipitation falls between maritime-like and continental-like patterns, leaning more toward continental convection. This varies significantly with TCs in Southeast China but is similar to that observed in coastal-front-like rainbands, suggesting extratropical influence. A detailed analysis of the vertical profile of cloud droplets shows a unique “top-down” phenomenon during the extratropical transition process of the TC, where the development of lower-level clouds follows that of upper-level clouds, inconsistent with previous studies and the case for comparison. Further investigation indicates the significant role of the intrusion of dry and cold air from upper levels and the presence of high humidity in low levels in driving this phenomenon. Our results will provide novel insights into cloud and precipitation microphysics associated with TCs in midlatitude regions.

Peripheral intravascular lithotripsy to facilitate transfemoral transcatheter aortic valve replacement – Defining optimal treatable peripheral arterial disease burden

BackgroundTransfemoral transcatheter aortic valve replacement (TF-TAVR) has proven superior to alternative access. However, some patients evaluated for TF-TAVR are unfit secondary to peripheral arterial disease (PAD). Peripheral intravascular lithotripsy (IVL) can facilitate femoral access. This study aimed to characterize optimal lesions that can be treated with IVL. MethodsSingle-center, retrospective analysis of an institutional database, queried from 1/2018 through 7/2023 for all patients who underwent TAVR. Patients who received IVL-facilitated transfemoral access were analyzed. ResultsOf 2862 TAVR cases identified, 92 (3.2 %) underwent lithotripsy. The IVL-facilitated cohort had a mean age of 78 ± 9.2 years and 45 % were female. The right common iliac artery was most treated (47). Most IVL was performed with 7-mm balloons (73.9 %). All cases were successful. 30-day mortality was 1.1 % (1/92). ConclusionsIn our cohort, complications after IVL-facilitated TF-TAVR were more common with small vessel diameter (≤4.7 mm), significant luminal loss (>50 % stenosis), and heavy calcium burden (arc calcification >180°). The findings support the use of IVL to expand the population of patients who can undergo TF-TAVR without the increased risks associated with the various forms of alternative access. Summary for annotated table of contentsIVL-facilitated TF-TAVR is safe and feasible. Despite its introduction to TAVR clinical practice in 2018, IVL-facilitated TF-TAVR is not regularly performed and could increase the population of patients eligible for TF-TAVR.

Microwave ablation on ex vivo porcine pancreas: The influence of ablation parameters on ablation results and fat liquefaction.

The pancreas is adjacent to critical organs; excessive microwave ablation (MWA) can result in serious complications. The purpose of this paper is to provide the reference data of pancreas MWA for clinicians, analyze the ablation outcomes under different ablation parameters, and determine the critical temperature of pancreatic surface fat liquefaction outflow. Combinations of two power levels (30 W and 55 W), three antenna diameters (1.3 mm, 1.6 mm, and 1.9 mm), and three ablation times (1 min, 1.5 min, and 2 min) were applied to an ex vivo pig pancreas. Temperature measurements were taken at four thermocouple points. The center point is located 5 mm horizontally from the antenna slot, with a temperature measurement point located 5 mm above, below, and to the right of the center point. Main effect analysis and variance analysis were used to quantify the influences of each factor on the ablation outcomes. At 30 W, the antenna diameter contributing the most at 48.5%. At 30 W-1.3 mm-1 min, the spherical index (1.41) is closest to 1. At 55 W, the coagulation zone size was almost only affected by the ablation time, with a contribution rate of 28.7%, the temperature at point C exceeds point B. On the surface of the ex vivo porcine pancreas, the fat outflow temperature was 54ã. Ablation combinations with low power, short duration, and small antenna diameter results in a more nearly spherical coagulation zone. When performing MWA on the pancreas, it is advisable to avoid areas with higher fat content, while keeping the pancreatic surface temperature below 54°C.

Single bundle hamstrings autograft preparation techniques for anterior cruciate ligament reconstruction: current concepts.

Anterior cruciate ligament reconstruction (ACLR) is one of the most common orthopedic procedures, and huge variation exists in the surgical technique. Single bundle hamstrings autograft reconstruction is a common method and has good clinical outcomes. A criticism of the hamstrings autograft is a small graft diameter, often less than 8-mm, which has been associated with increased re-rupture rates. Several graft preparation techniques for single bundle hamstrings autograft exist. Perioperative decisions include the number of tendons utilized, number of graft strands, graft configuration, and femoral and tibial fixation methods. Awareness of the minimum tendon and graft length required to produce each graft variation is necessary to avoid common pitfalls. However, intraoperative graft modification is possible to maximize graft diameter, and obtain proper fixation. The objective of this current concepts review is to describe the indications, surgical anatomy, technique, intraoperative tips, clinical outcomes, and complications for single bundle hamstrings autograft preparation techniques in ACLR.

Improved energy method and agglomeration influence of carbon nanotubes on polymer composites

In this paper, the geometric analysis of carbon nanotubes (CNTs) without external loading is carried out by energy method. Based on the theory of molecular mechanics, an improved mechanical model is proposed to predict the energy of armchair carbon nanotubes under stress-free conditions, and the diameter of CNTs is estimated according to the principle of minimum energy. The results show that the diameter obtained by the improved model is larger, but basically consistent with that obtained by conformal mapping. The inversion energy term is added to the modified model, and the inversion energy term related to atomic curvature is characterized by the conization angle. It can be seen from the error that the inversion energy of carbon nanotubes can not be neglected in the stress-free state, especially in the case of small diameter. The agglomeration of nanotubes is one of the important factors, which affects the effective elastic modulus of nanocomposites. Here, a new micro-mechanics model consisting of both agglomeration of CNTs and pure matrix is also presented to analyze its effect on the effective elastic modulus. It is noted from the results that the stiffness of nanocomposites is very sensitive to the CNTs agglomeration.

Pore-scale investigation of forced imbibition in porous rocks through interface curvature and pore topology analysis

Forced imbibition, the invasion of a wetting fluid into porous rocks, plays an important role in the effective exploitation of hydrocarbon resources and the geological sequestration of carbon dioxide. However, the interface dynamics influenced by complex topology commonly leads to non-wetting fluid trapping. Particularly, the underlying mechanisms under viscously unfavorable conditions remain unclear. This study employs a direct numerical simulation method to simulate forced imbibition through the reconstructed digital rocks of sandstone. The interface dynamics and fluid–fluid interactions are investigated through transient simulations, while the pore topology metrics are introduced to analyze the impact on steady-state residual fluid distribution obtained by a pseudo-transient scheme. The results show that the cooperative pore-filling process promoted by corner flow is dominant at low capillary numbers. This leads to unstable inlet pressure, mass flow, and interface curvature, which correspond to complicated interface dynamics and higher residual fluid saturation. During forced imbibition, the interface curvature gradually increases, with the pore-filling mechanisms involving the cooperation of main terminal meniscus movement and arc menisci filling. Complex topology with small diameter pores may result in the destabilization of interface curvature. The residual fluid saturation is negatively correlated with porosity and pore throat size, and positively correlated with tortuosity and aspect ratio. A large mean coordination number characterizing global connectivity promotes imbibition. However, high connectivity characterized by the standardized Euler number corresponding to small pores is associated with a high probability of non-wetting fluid trapping.

Clipless internal mammary artery harvesting for minimally invasive coronary artery bypass grafting using the shear-tip harmonic scalpel.

The internal mammary artery (IMA) is the most commonly used graft in coronary artery bypass grafting (CABG) because of its superior long-term patency rate. However, its small diameter poses challenges in handling, and any vascular damage that may occur during harvesting can significantly affect surgical outcomes. The primary focus during IMA harvesting is to ensure safe and effective hemostasis without direct vascular injury, while ensuring secure and reliable ligation of the vascular branches. Various methods using multiple surgical instruments have been used for this purpose. Unlike traditional instruments, the shear-tip Harmonic scalpel offers more precise vessel branching control, while minimizing damage to surrounding tissues. In this study, we assessed the utility of the shear-tip Harmonic scalpel in patients undergoing minimally invasive coronary artery bypass grafting (MICABG). From April 2019 to May 2023, a total of 40 patients underwent MICABG. The IMA was harvested using the shear-tip Harmonic scalpel with a clipless skeletonized technique. In this cohort, 5 patients underwent complete endoscopic harvesting, while 34 patients underwent direct visualization harvesting through minimal thoracotomy. Graft patency was assessed by measuring a Doppler flowmeter in the bypass conduit. Successful graft patency was achieved in all patients. The mean duration of IMA harvesting was 87 min. In total, 38 of the 40 patients underwent MICABG without the need for cardiopulmonary bypass, ensuring a stable procedure. There were no graft-related events or complications observed in any of the patients, and all were discharged without any issues. During a median follow-up period of 15.2 months, only one patient experienced graft occlusion necessitating intervention. The utilization of shear-tip Harmonic scalpel for IMA harvesting in MICABG is feasible and yields stable early results.

A real-world study evaluating the safety and utility of a two-row stapler reload on pulmonary vasculature.

Endoscopic staplers are common surgical devices used for the ligation and division of vasculature in thoracic procedures. When a stapler ligates and divides pulmonary vasculature, potentially catastrophic intraoperative bleeding at the staple-line may occur. The aim of this study was to confirm the safety and discuss the utility of a two-row stapler reload, by assessing the incidence of clinically necessary intraoperative hemostatic intervention when applied to pulmonary vasculature in real-world applications. This study was designed as a prospective non-comparative registry study conducted in seven centers across the United States, to confirm the safety and performance of Signia™ Small Diameter Reloads (SDR) when used for indicated thoracic surgical procedures. The primary endpoint was the incidence of hemostatic intervention related to the ligation and division of pulmonary arteries and veins. A five-point Likert scale scored hemostasis of each SDR staple-line. Secondary endpoints included the incidence of device-related only adverse events (AEs), device deficiencies, and procedure-related hospital readmission up to and including 30 days post operation. SDR was fired 302 times across pulmonary vasculature in 120 subjects. Three firings required clinically necessary hemostatic intervention for an intervention rate of 0.99% (3 of 302 firings). Moreover, 97.5% (117 of 120 subjects) had intact SDR staple-lines regardless of surgical access or stapler handle preference. Only 4 (3.3%) thoracoscopic and robotic procedures converted to open, but none were due to SDR staple-lines. There was no statistically significant difference between the Likert score of transected arteries compared to veins (P=0.61). There were no device deficiencies or device-only related AEs reported. In this study, the two-row stapler reloads demonstrated favorable safety and efficacy profiles when fired across hilar vessels in the thoracic space with a 99% hemostatic rate, independent of surgical access and stapler handle preference.

Uncoupled analysis of piles stabilized transmission tower slopes

It is a common engineering practice to adopt piles to improve the stability of potentially unstable slopes. In this paper, parametric analysis of a homogeneous transmission tower slope stabilized with a row of small diameter steel piles is conducted using an uncoupled numerical method in which the pile response and slope stability are considered separately. The transmission tower slope stability is analyzed using the limit equilibrium solutions, and the stabilizing pile-soil system is modeled as a simple beam on subgrade reaction foundation. Attempts have been made to study the effect of soil property, slope geometry, pile property, pile spacing and pile position on the safety factor of the transmission tower slope stabilized with small diameter steel piles. The study shows that they have a combined effect on the performance of small diameter steel piles to stabilize transmission tower slopes.

In Ukrainian

The CMs were obtained in argon in three stages: 1) heating (4 grad/min) to the specified temperature t in the range of 350–825 °С; 2) isothermal exposure 1 h; 3) cooling, washing from alkali and drying. Samples are denoted as CM(t). The CM yield (Y, %) and CMs elemental composition are determined. Based on low-temperature (77 K) nitrogen adsorption-desorption isotherms, integral and differential dependences of the specific surface area SDFT (m2/g) and pore volume V (cm3/g) on the average pore diameter (D, nm) were calculated by 2D-NLDFT-НS method (SAIEUS program). They were used to define volumes of ultramicropores (Vumi), supermicropores (Vsmi) and micropores (Vmi). The total pore volume V was calculated from the nitrogen amount adsorbed at a relative pressure p/p0 ~ 1.0. The S values of ultramicropores (Sumi), supermicropores (Ssmi) and micropores (Smi) were similarly determined. The CM yield was established to decrease linearly (R2 = 0.979) from 70.2 to 45.3 % with an increase in temperature from 350 to 825 °С. The carbon content decreases to a minimum value at 500 °С (72.6 %), and then increases to a maximum value (87.5 %) at 825 °С; the oxygen content changes antibatically. Two temperature regions were identified: region I (≤ 500 °С) of increasing the oxygen content due to reactions in which KOH acts as a donor of O atoms; region II (≥ 500 °C) of dominating the thermal destruction of functional groups (carboxyl, lactone, ester) with the release of CO and CO2, and condensation increasing the size of polyarenes of the CM secondary framework and formsng single Сar-Саr bonds between them. The CM(350) sample was found to contain only mesopores (D ≥ 10 nm) and macropores. An activation temperature increase to 400 °C initiates the additional formation of small-diameter micropores and mesopores. In samples CM(400) - CM(825), the main portion of newly formed pores falls on pores with D ≤ 5 nm. With increasing temperature, the micropores volume increases almost linearly (R2 = 0.992). The Vumi and Vsmi volumes increase up to 600 °C. At higher temperatures the ultramicropores volume decreases due to transforming ultramicropores (D ≤ 0.7 nm) into supermicropores (D = 0.7–2.0 nm). Portion of the ultramicropores volume changes with a maximum (23.9 %) in the CM(600) sample. The SBET specific surface area linearly (R2 = 0.992) increases with temperature up to 1729 m2/g. The SDFT values are close to SBET, but noticeably lower (1514–1530 m2/g) for CM(785)-CM(825). The micropores specific surface area increases to 1415 m2/g, and ultramicropore surface Sumi changes extremely with a maximum (526 m2/g) for the CM(600) sample, which should be expected based on the temperature dependence of the Vumi parameter. The decrease in Sumi values after the maximum is compensated by an increase in the supermicropore surface. Such an effect - the redistribution of pores by size in the microporous range (D ≤ 2 nm) with an increase in the alkaline activation temperature is not described in the literature. The portion of the micropores surface is dominant (92.6–97.0 %) in samples prepared at t ≥ 450 °C. The portion of the ultramicropore surface is maximum (56.3 %) in CM(500). Pores are revealed that do not form at all at 450–750 °C. These are supermicropores (D = 0.96–2.00 nm) and mesopores of small diameters (D = 2.0–2.82 nm). This effect was assumed to be due to the properties of the CM supramolecular framework, which is formed from polyarene fragments of the initial and activated coals having polyarenes with diameters of the same order (1.68–2.54 nm).

Boundary effect on the soil strength estimation from T-bar penetration tests

The T-bar penetration tests have gained widespread use in assessing the undrained shear strength of marine clays. However, when dealing with model tests or sampled soil with a small diameter of the tube, the reliability of T-bar test results is influenced by both the boundary effect and the soil flow mechanism around the T-bar. In this paper, a comprehensive investigation into the boundary effect on T-bar penetration resistance was conducted by using the large deformation finite element (LDFE) method in conjunction with laboratory tests. The study reveals that the boundary conditions significantly impact the T-bar resistance when the lateral boundary dimension is smaller than 12D. Specifically, the T-bar penetration resistance is underestimated for smooth boundaries and overestimated for rough boundaries. For soils with higher strength, a larger boundary size is required. The bottom boundary also affects the T-bar resistance until the full-flow mechanism is established. However, once the full-flow mechanism is achieved, the boundary effect on T-bar penetration resistance diminishes, even for small lateral boundary sizes (2D). Considering the fact that it is challenging to attain the full-flow mechanism, especially for higher strength soils, a simple algorithm is proposed to estimate soil strength based on a shallow penetration depth (2D). This algorithm is validated through laboratory tests. To address the difficulty in achieving the full-flow mechanism, by applying the overburden pressure during the T-bar test, a novel T-bar test method is suggested. This innovative approach promises to resolve the issue effectively.

Effect of endoscopic sphincterotomy and endoscopic papillary balloon dilation endoscopic retrograde cholangiopancreatographies on the sphincter of Oddi.

Endoscopic retrograde cholangiopancreatography (ERCP), with its clinical ad-vantages of less trauma and faster recovery, has become the primary treatment for choledocholithiasis. To investigate the effects of different ERCP procedures on the sphincter of Oddi. The clinical data of 91 patients who underwent ERCP at Yixing Hospital of Traditional Chinese Medicine between February 2018 and February 2021 were analyzed retrospectively. The patients were divided into endoscopic sphincterotomy (EST, n = 24) and endoscopic papillary balloon dilation (EPBD, n = 67) groups. The duration of operation, pancreatic development, pancreatic sphincterotomy, intubation difficulties, stone recurrence, and incidence of reflux cholangitis and cholecystitis were statistically analyzed in patients with a history of choledocholithiasis, pancreatitis, and Oddi sphincter dysfunction in the EST and EPBD groups. Differences in hypertension, diabetes, increased bilirubin, small diameter of the common bile duct, or ampullary diverticulum between the two groups were not significant. Statistically significant differences were observed between the two groups concerning sex and age (< 60 years). Patients with a history of choledocholithiasis, pancreatitis, and Oddi sphincter dysfunction were higher in the EST group than in the EPBD group. The number of cases of pancreatic development, pancreatic duct sphincterotomy, and difficult intubation were higher in the EST group than in the EPBD group. The number of Oddi's sphincter manometries, ERCP surgical outcomes, and guidewires entering the pancreatic duct several times in EST group were lower than those in the EPBD group. The numbers of stone recurrences, reflux cholangitis, and cholecystitis were higher in the EST group than in the EPBD group. In summary, common bile duct stones, pancreatitis history, and multiple guided wire introductions into the pancreatic duct are independent risk factors for EST and EPBD. Based on this evidence, this study can provide actionable insights for clinicians and researchers.

Anticancer, antioxidant, and antimicrobial activities of nanoemulsions based on water-in-olive oil and loaded on biogenic silver nanoparticles

Abstract Nanoemulsions (NEMs) are more stable and permeable than regular emulsions because of their increased surface area and smaller particle sizes, which are stabilized by emulsifiers and consist of nanometer-sized droplets. Utilization of an olive oil nanoemulsion (NEM-olive oil) loaded with silver nanoparticles (Ag-NPs) derived from marine alga Turbinaria turbinata may be effective against microorganisms and cancer cell lines. NEM-olive oil was made by mixing olive oil, surfactant (Span:Tween (28:72)), and D water (1:4:5). The marine alga Turbinaria turbinata was used for the synthesis of Ag-NPs (Tu-Ag-NPs), and combined with NEM-olive oil (1:1) to synthesize Ag-NPs loaded in olive oil–water nanoemulsion (Ag/NEM-olive oil). Transmission electron microscopy, energy-dispersive X-ray analysis, zeta potential, Fourier transform infrared, and X-ray powder diffraction spectroscopy were used to characterize the nanoparticles. Both NEM-olive oil and Ag/NEM-olive oil nanoparticles showed a negative surface charge and small diameter. The major components of NEM-olive oil are dodecanoic acid, 2-penten-1-yl ester, 9-octadecenoic acid, and oleic acid. All tested nanoparticles exhibited anticancer activity against the CACO-2 cell line and Hep G2, and antimicrobial activities against E. faecalis, S. aureus, E. coli, and C. albicans. The present research suggested that olive oil NEM loaded with marine algae Ag-NPs can be a safe and economical anticancer, antimicrobial, and drug delivery.

Experimental and numerical research on the debris bed formation in severe accidents of nuclear reactors

The formation and coolability of the debris bed play a crucial role in the core meltdown process in nuclear reactors. Previous studies mainly focused on experiments involving interactions between small masses of molten material and water, with emphasis on the steam explosion process, lacking analytical data on debris beds and fragments. Therefore, the formation of the debris bed is studied by visual experiments, along with the relevant models are established and applied in this study. In the experiments, a large mass of zirconium dioxide is heated to a molten state in the crucible and then released into a water tank through the release device. The water tank is equipped with four glass windows and high-speed cameras to capture snapshots.Firstly, experiments on the formation of hundred-kilogram-scale debris beds were conducted using the prototype material, zirconium dioxide. The molten material temperature was 3000 K, the molten material mass ranged from 50 to 100 kg, the jet diameter varied from 10 to 20 mm, the water pool depth ranged from 0.55 to 1 m, and the water subcooling varied from 10 to 80 K. Visualized images of the debris bed formation were obtained, and an experimental database of debris bed formation was established, primarily including key parameters such as debris morphology, debris size, debris bed accumulation form, and debris bed porosity. The results indicate that the rise in the mass of molten material and the decrease in water subcooling increase the proportion of large-sized fragments. The experiments did not form a “cake” debris bed but instead achieved loose debris beds due to the small jet diameter. With an increase in the jet diameter and a decrease in water subcooling, the porosity of the debris bed will also increase. Subsequently, computational analysis codes were developed for the processes of jet break-up, debris bed accumulation, and formation, and finally, the deviation of the predicted accumulation morphology was less than 20 %. The results reveal that the influence of the jet diameter and mass of the molten debris on the deposition characteristics of the debris bed is very pronounced. Experimental research and code development hold significant reference value for the formulation of preventive and mitigative measures for severe accidents in nuclear power plants.

Downed woody debris varies with climate and harvesting treatment in Douglas-fir forests of British Columbia, Canada

Downed woody debris is important for biodiversity, forest regeneration, and carbon, nutrient, and water cycling, and past studies have examined how the coarse fraction is affected by climate or harvesting. In a field study in Douglas-fir dominated forests, we expand existing knowledge by investigating the interacting effects of climate and harvesting on downed woody debris of all sizes. Across a 900-km long latitudinal gradient in British Columbia, we found that coarse woody debris (CWD, &amp;gt;7.5 cm diameter) in humid climates contained 700% greater carbon stocks, had 500% greater volume, and was more diverse than in arid climates. Pre- and post-harvest, small and fine woody debris comprised a higher proportion of total woody debris carbon stocks in arid than moist climates, especially after clearcutting and seed tree treatments. Harvesting generally decreased total CWD volume, but it was not depleted on any site. Harvesting substantially reduced the volume of large, highly decomposed CWD except at the two most arid sites, and losses of large CWD increased with increasing tree removal. These losses were accompanied by a pulse of fresh, small diameter CWD and SWD which are short-term organic nutrient sources but have less habitat value than larger pieces and contribute to fuel loads. Because CWD was less abundant in arid than humid mature forests, care must be taken on arid sites to avoid its depletion during harvesting, especially clearcutting, where future woody debris inputs will not occur for decades.

Preparation of SiO2 nanotubes and nanoparticles in the presence of L-tartaric acid by sol-gel method and their electrochemical performance for Li-ion batteries

Recently, SiO2 has attracted increasing attention as an anode material for lithium-ion batteries (LIBs) owing to its low cost and high theoretical specific capacity. However, its inherent poor conductivity limits its practical application. To address this issue, nanostructured material design is considered an effective solution. Herein, based on the traditional ammonium tartrate template-directed sol-gel method, we use low-cost and easily available L-tartaric acid in place of D, L-tartaric acid to prepare high-yield silica nanotubes (SNTs) with a thin wall (ca. 50 nm), small diameter (ca. 150 nm), rough surface and open ends, as well as tiny spongy-like silica nanoparticles (SNPs) by adjusting the feeding amount and feeding mode of NH4OH solution. The electrochemical characterization results suggest that the SNTs show better cyclability and rate performance than the SNPs, which maintain a reversible capacity of 741.3 mAh g−1 after 500 cycles at a current density of 0.4 A g−1 and deliver a high rate capacity of 819.4 mAh g−1 at a high current rate of 2 A g−1. The excellent electrochemical performance suggests that hollow one-dimensional hollow nanotubes are more efficient in improving the electrochemical performance of SiO2 than zero-dimensional nanoparticles, and SNTs with thin tube walls and rough surfaces are demonstrated to be fascinating and promising anode materials for LIBs.

Density Functional Investigation of [001] and [111] SiNWs and the Effect of Doping with Boron and Phosphorus

In the present study, we investigate the influence of boron (B) and phosphorus (P) (p- and n-type, respectively) doping on the electronic properties of ultra-thin silicon nanowires (SiNWs) by gradient-corrected density functional calculations with the Perdew–Burke–Ernzerhof (PBE) approximation. In the limit of very small diameters (5–8 Å), both pristine and highly active unsaturated SiNWs with orientations along the [001] and [111] directions exhibit electronic states around the Fermi level, indicative of conductive properties. Conduction is further enhanced by the introduction of doping atoms, as demonstrated by the relative change in the band structures of SiNWs with and without B and P doping. This investigation provides an important insight into the electronic states of SiNWs, which are candidates for future electronics or sensing applications.

СОКОПРОДУКТИВНОСТЬ КЛЕНА ВЫСОКОГОРНОГО

In the North Caucasus are presented data on the intensity of sap production and sap productivity of the Trautvetter maple. Experimental tapping was carried out in an old-growth maple forest in the forest fund of North Ossetia-Alania, the Koban tract. Maple tapping was carried out by laying drill channels with a diameter of 10 mm and a depth of no more than 30 mm. From 1 to 4 channels were laid on one trunk. A polyvinyl chloride tube with an outer diameter of 10 mm was used as a sap line. Plastic containers with a volume of 5 and 10 liters served as juice collectors. The volume of secreted juice was determined with an accuracy of 10 ml. It has been established that the intensity and duration of juice secretion depends on the weather conditions at the beginning of the growing season. The sap productivity of the Trautfetter maple also depends on the size of the tree and its condition. A direct and strong dependence of the intensity of juice secretion on the diameter of the trunk has been proven - the larger the diameter, the more juice. At the same time, there are cases when the intensity of sap production by trees with a small trunk diameter is higher than that of trees with a trunk diameter of about 1 m. It is noted that the presence of heart rot and hollowness of the trunk affects both the intensity of sap production and sap productivity. An interesting feature was revealed in individual Trautfetter maple trees: when 2-4 sapling canals are laid on one trunk, sap flow from one, or less often from two canals at once, quickly stops. The period of rapid decrease in juice secretion takes from 30 minutes to several hours. A characteristic phenomenon for alpine maple is the growth of trees in nests, when from 2 to 10-12 trunks develop from a single root system. It is indicated that the intensity of sap production does not depend on the number of trees in the “nest”, and the overall sap productivity of the “nest” is higher than that of individual trees.

0, 1, 2, and 3-Dimensional zinc oxides enabling high-efficiency OLEDs

In the pursuit of high-efficiency organic light-emitting diodes (OLEDs), this paper unveils the potential of zinc oxide (ZnO) nanostructures of various dimensions (0,1,2, and 3D), doped in hole injection layer (PEDOT:PSS). Unique enhancements were demonstrated in forms from nanoparticles (0D) to nanowires (1D), nanosheets (2D), and nanoflowers (3D), revolutionizing OLED performance. Specifically, the incorporation of 0D-ZnO doped in PEDOT:PSS resulted in remarkable efficiency improvements of 19 % in maximum power efficacy (PEmax), 19 % in maximum current efficacy (CEmax) and 24 % in maximum external quantum efficiency (EQEmax), compared with the undoped counterpart. Elevating the dimensions to 1D-ZnO (20 nm), when doped in PEDOT:PSS, enabled an increment of 46, 54 and 64 % in PEmax, CEmax and EQEmax, respectively. Furthermore, 2D-ZnO (annealed at 400 °C) doped in PEDOT:PSS achieved notable performance improvements, with enhancements of 24 % in PEmax, 23 % in CEmax, and 28 % in EQEmax. Despite size limitations, 3D-ZnO doped in PEDOT:PSS exhibited enhancements of 11 % in PEmax, 15 % in CEmax, and 20 % in EQEmax. We achieved the best results by integrating 1D-ZnO into PEDOT:PSS, which may be attributed to the small diameter of the 1D-ZnO structure when compared to 0D, 2D, and 3D ZnO, resulting in superior OLED performance. These findings demonstrate the significant potential of ZnO nanostructures doped in PEDOT:PSS in enhancing the performance of green OLEDs, and paving the way for more sustainable, cost-effective, and efficient OLEDs for display and lighting applications. Continued research on ZnO and other inorganic materials holds promise for further advancements in OLED technology and a brighter, more energy-efficient future.

Long-term results of endovascular treatment of patients with coronary heart disease using various PCI technologies

Objective: the effectiveness and safety of endovascular treatment of coronary artery disease in coronary artery disease using various technologies of percutaneous coronary intervention (PCI) was evaluated — implantation of drug-coated metal stents, implantation of bioresorbable stenting scaffolds, the use of drug-coated coronary balloon catheters in the long- term period, 10 years after PCI.Materials and methods: data obtained from 324 patients with coronary heart disease after PCI using the previously mentioned treatment methods. The endpoint was the loss of the target vessel lumen (TLF), a combination of cardiac death, myocardial infarction, and revascularization associated with the target vessel.Results: the treatment of patients with coronary heart disease using implantation of drug-coated metal stents, bioresorbable stenting scaffolds or drug-coated coronary balloon catheters is safe and has low rates of cardiac mortality, myocardial infarction and revascularization of the target vessel in the long term. In cases where implantation of stents or scaffolds was contraindicated or impossible due to the small diameter of the artery, diffuse extended lesion and high risk of restenosis, angioplasty with a coronary balloon catheter with an antiproliferative drug coating takes place, showing positive long-term results.