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The growing interest in hybrid devices that combine two-dimensional materials with a superconductor presents new challenges in material deposition. In this study, we demonstrate that achieving excellent superconducting properties by RF (radio frequency) sputtering does not require access to a high-end system but rather depends on the precise control of sputtering parameters and the selection of an appropriate lithographic process. We highlight the challenges and present practical solutions to deposit high-quality niobium thin films for the lithographic production of superconducting hybrid nanostructures. The influence of various deposition parameters, such as power, argon pressure, and film thickness, on the resultant superconducting characteristics can already be deduced at liquid nitrogen temperatures. Furthermore, niobium films tend to degrade when a PMMA [poly(methylmethacrylate)] resist is employed in the fabrication of superconducting nanostructures. We propose alternative and simple strategies to address this issue, which ultimately result in the restoration of the thin-film quality. [ABSTRACT FROM AUTHOR]

The theory-led prediction of LaBeH8, which has a high superconducting critical temperature (Tc) above liquid nitrogen under a pressure level below 1 Mbar, has been experimentally confirmed. YBeH8, which has a structural configuration similar to that of LaBeH8, has also been predicted to be a high-temperature superconductor at high pressure. In this study, we focus on the structural phase transition and superconductivity of YBeH8 under pressure by using first-principles calculations. Except for the known face-centered cubic phase of Fm 3 ̄ m, we found a monoclinic phase with P 1 ̄ symmetry. Moreover, the P 1 ̄ phase transforms to the Fm 3 ̄ m phase at ∼200 GPa with zero-point energy corrections. Interestingly, the P 1 ̄ phase undergoes a complex electronic phase transition from semiconductor to metal and then to superconducting states with a low Tc of 40 K at 200 GPa. The Fm 3 ̄ m phase exhibits a high Tc of 201 K at 200 GPa, and its Tc does not change significantly with pressure. When we combine the method using two coupling constants, λopt and λac, with first-principles calculations, λopt is mainly supplied by the Be–H alloy backbone, which accounts for about 85% of total λ and makes the greatest contribution to the high Tc. These insights not only contribute to a deeper understanding of the superconducting behavior of this ternary hydride but may also guide the experimental synthesis of hydrogen-rich compounds. [ABSTRACT FROM AUTHOR]

The theory-led prediction of LaBeH8, which has a high superconducting critical temperature (Tc) above liquid nitrogen under a pressure level below 1 Mbar, has been experimentally confirmed. YBeH8, which has a structural configuration similar to that of LaBeH8, has also been predicted to be a high-temperature superconductor at high pressure. In this study, we focus on the structural phase transition and superconductivity of YBeH8 under pressure by using first-principles calculations. Except for the known face-centered cubic phase of Fm 3 ̄ m, we found a monoclinic phase with P 1 ̄ symmetry. Moreover, the P 1 ̄ phase transforms to the Fm 3 ̄ m phase at ∼200 GPa with zero-point energy corrections. Interestingly, the P 1 ̄ phase undergoes a complex electronic phase transition from semiconductor to metal and then to superconducting states with a low Tc of 40 K at 200 GPa. The Fm 3 ̄ m phase exhibits a high Tc of 201 K at 200 GPa, and its Tc does not change significantly with pressure. When we combine the method using two coupling constants, λopt and λac, with first-principles calculations, λopt is mainly supplied by the Be–H alloy backbone, which accounts for about 85% of total λ and makes the greatest contribution to the high Tc. These insights not only contribute to a deeper understanding of the superconducting behavior of this ternary hydride but may also guide the experimental synthesis of hydrogen-rich compounds. [ABSTRACT FROM AUTHOR]

Egg (oocyte) vitrification is the dominant method for preserving fertility for women of reproductive age. However, the method is typically performed by hand, requiring precise (∼0.1 to 10 μL) and time-sensitive (∼1 s) liquid exchange of cryoprotectants (CPA) around eggs as well as fine handling of eggs (∼100 μm) for immersion into liquid nitrogen (LN2). Here, we developed a microfluidic platform for programmable vitrification. Our platform is based on a millimeter-sized hanging droplet inside which a given egg is suspended and subjected to liquid exchanges within seconds. After programmable exposures to CPA, the egg is extracted from the liquid–air interface of the droplet using a motorized fine-tip instrument and immersed into LN2 for vitrification. To benchmark our platform with the manual method, we vitrified over a hundred mouse eggs and found comparable percentages (∼95%) for post-vitrification survivability. In addition, our platform performs real-time microscopy of the egg thereby enabling future studies where its morphology may be linked to functional outcomes. Our study contributes to the ongoing efforts to enhance the automation of embryology techniques towards broader applications in reproductive medicine both for clinical and research purposes. [ABSTRACT FROM AUTHOR]

Heterostructured ferritic steels with bimodal-grained lamellar (BG-L) and ultrafine-grained lamellar (UFG-L) microstructure were prepared through a warm deformation process. The BG-L steel exhibits enhanced mechanical properties compared to conventional quenched and tempered (QT) steel. While the UFG-L steel demonstrates an outstanding combination of strength, ductility, and toughness. Furthermore, the UFG-L steels exhibit no ductile-to-brittle transition (DBT) from room temperature (RT) to liquid nitrogen temperature (LNT) and the Charpy impact energy remains as high as 314 J at LNT. The enhanced toughness at LNT can be attributed to the crack-arrester mechanism caused by grain-boundary delamination. [ABSTRACT FROM AUTHOR]

Liquid nitrogen is a widely utilized effective low-temperature cooling medium, also employed in the ATR-GG (Gas Generator cycle Air Turbo rocket) engine to cool high-temperature components. Due to the high-temperature work environment and the ease with which liquid nitrogen evaporates and boils, liquid nitrogen would experience a flash boiling process. In order to study the influence of flash boiling on spray characteristics, experiments and simulations were conducted with two types of hollow-cone nozzles and two types of solid-cone nozzles under subcooled water at normal temperature which is not affect by flash boiling and superheat liquid nitrogen inflow conditions. The research found that flashing already begins inside the nozzle, significantly reducing the discharge coefficient of the solid-cone nozzle. The nitrogen gas-liquid mixture fills the air core of the hollow-cone spray, resulting in a comparatively smaller impact on the discharge coefficient. The liquid nitrogen spray exhibit spray collapse, unable to achieve the spray cone angels as the water spray. The major reason is that during the flashing process, nitrogen vapor expansion enhances the axial velocity, reducing the spray cone angle. The study recommends using hollow-cone nozzles to mitigate the impact of flash boiling on the spray characteristics. [ABSTRACT FROM AUTHOR]

This work focuses on the synthesis of a liquid fertiliser deriving from sheep wool waste.. Nitrogen-rich sheep’s wool underwent alkaline hydrolysis with potassium hydroxide. The product obtained by an alkaline hydrolysis process contains nitrogen, phosphorus and potassium, which are the main nutrients necessary for plant growth The hydrolysis parameters, temperature, reaction time, and alkaline agent concentration were optimized using response surface methodology and Box-Behnken design. The amino acids and oligo-elements content of the resulting product also appear to have a positive effect combined with the nutrients when applied to the agricultural field. An adding phosphoric acid to incorporate phosphorus and reduce pH was made, addressing potential stress from alkaline conditions, especially in Moroccan soils. A stability study at pH levels (5, 6, 7, 8) over 120 hours and at temperatures (17°C and 25°C) indicated that neutralization at acidic pH leads to phosphorus potassium salts formation. This new fertilizer is designed for agronomic application. [ABSTRACT FROM AUTHOR]

The use of VIV and CuII spins to design weakly coupled and dissymmetric spin systems has been examined. Such systems were synthesized using porphyrin‐based complexes, with external coordination sites allowing for the formation of dimers via a PdII linker ion. Continuous‐wave (CW) Electron Paramagnetic Resonance (EPR) spectroscopy allowed the unequivocal magnetic characterization of the mononuclear precursors VO and Cu. The porphyrin dimer (VO)PdCu presented a broad and overlapped spectrum that was more pronounced than for the previously reported (VO)Pd(VO), hinting at the effect of weak interspin interactions between dissimilar spins. Pulsed EPR experiments on VO, (VO)Pd(VO) and (VO)PdCu samples diluted in a diamagnetic matrix confirmed that this complication is also present in the Field‐Swept Echo‐Detected (FSED) spectra of the heterometallic (VO)PdCu system. Despite the strongly overlapped field‐swept spectra, spin nutation experiments revealed two distinct oscillations in the case of (VO)PdCu, which are assigned to transitions with different spin characters. Remarkably, coherence is retained above liquid nitrogen temperatures for all complexes, in particular up to 295 K for VO and (VO)Pd(VO) and 150 K for (VO)PdCu. [ABSTRACT FROM AUTHOR]

Large TiN inclusions in nickel-based superalloys promote micropore formation, compromising the mechanical properties of the alloys. However, current research lacks a comprehensive coupled model that considers both solute element microsegregation and TiN precipitation specifically in nickel-based superalloys. This study investigated TiN precipitation during the solidification of IN718 alloys through a combined thermodynamic and kinetic approach. A modified Clyne–Kurz model was applied to account for multi-element microsegregation, enabling an integrated analysis of both microsegregation and precipitation processes. The results indicated that solute elements in the molten alloy segregated to varying degrees during solidification. At an initial nitrogen concentration of 25 ppm, TiN inclusions precipitated when the solid fraction reached 0.256, eventually resulting in a total TiN precipitation of 64 ppm by the end of solidification, while residual nitrogen in the liquid phase decreased to 1.3 ppm. Increasing the initial nitrogen concentration from 10 ppm to 40 ppm advanced the onset of TiN precipitation and raised the total amount from 16 ppm to 126 ppm. Further analysis indicated that cooling rates of 0.03 °C/s, 0.06 °C/s, and 0.18 °C/s did not significantly affect the final TiN accumulation. [ABSTRACT FROM AUTHOR]

Sperm cryopreservation is a rather complex process that needs to be adapted to wild and domestic bird species to ensure adequate efficiency. This study aimed to determine the usability of different cryoprotectants in the cryopreservation of Gloster canary sperm. For this purpose, sperm samples were collected from 12 2‐year‐old male Gloster canaries three times a week using cloacal massage for 4 weeks. After individual evaluation, sperm samples from the canaries were combined. Mixed sperm were divided into two groups in the study. Overall, 8% dimethyl sulfoxide (DMSO) and ethylene glycol (EG) were used as cryoprotectants. Sperm samples were drawn into straws after adding Dulbecco's Modified Eagle Medium (DMEM) extender with high glucose ratio and two different cryoprotectants in a 1:1 ratio and frozen to −80°C with liquid nitrogen vapour and then stored in liquid nitrogen at −196°C. Frozen‐thawed semen samples were evaluated regarding motility, vitality, plasma membrane integrity (hypoosmotic swelling test [HOST]), density and abnormal spermatozoa rate. The highest motility value after freezing and thawing was determined in the EG group with 31.667% ± 4.773%. In addition, vitality, plasma membrane integrity and normal sperm morphology were statistically significantly higher in the EG‐frozen group, whereas head and tail abnormality was low (p < 0.05). This study determined that a DMEM extender containing 8% EG was more advantageous than a DMEM containing DMSO regarding spermatological parameters and could be used for long‐term storage of canary sperm. [ABSTRACT FROM AUTHOR]

Cryopreservation allows for the long-term storage of biological materials, ensuring their viability for future use and preserving biodiversity. This study aimed to develop an efficient protocol for the long-term in vitro conservation of fegra fig. In vitro precultured shoot tips of fegra fig with 0.3 M sucrose showed the highest regrowth percentage (100%) before plunging into liquid nitrogen. After plunging into liquid nitrogen, the regrowth percentage was 43.33%. Following cryopreservation, the recovered shoots were rooted and acclimatized to ex vitro conditions. The genetic fidelity of the acclimatized 8-week-old fegra fig plantlets after cryopreservation with their mother plant was tested using randomly amplified polymorphic DNA (RAPD), inter simple sequence repeats (ISSR), and start codon targeted (SCoT) molecular markers. Genetic similarity between the stored plantlets with their mother plant was 100% ensuring uniformity and true-to-type regenerated plants following cryopreservation. This study presents, for the first time, an efficient protocol for the genetic conservation of fegra fig. [ABSTRACT FROM AUTHOR]

A clean and effective unconventional fossil fuel is coalbed methane (CBM). The development of CBM is essential to reducing the lack of oil and gas resources, preventing coal mine gas mishaps, and safeguarding the atmosphere. After the coal samples prepared in this study were frozen and thawed by liquid nitrogen, the change rules of coal surface and internal pores were investigated by metallurgical microscopy and carbon dioxide adsorption. The results showed that: 1) The values of specific surface area, characteristic adsorption energy, and total SF microvolume of coal samples increased after freeze-thawing of liquid nitrogen, but the CO2 adsorption experiments showed that the pore width decreased, which indicated that the mechanism of freeze-thawing fracture effect coal by liquid nitrogen mainly increased the number of micropores in coal. 2) The water saturation of coal samples rose with the degree of surface cracking, but when the water content reached a specific level, the rise in surface porosity of coal reduced with the water saturation. 3) The increase in the number of cycles has a greater effect on the extent of expansion of pores on the coal surface than on the expansion of pores in the coal. [ABSTRACT FROM AUTHOR]

The article discusses the use of cryoinflation with liquid nitrogen as an alternative treatment for fistulas in hidradenitis suppurativa (HS). The study evaluated the efficacy and tolerability of cryoinflation in HS tunnels, showing promising results in terms of clinical improvement and ultrasound parameters. The procedure was well-tolerated by patients and demonstrated potential as a non-invasive therapy for HS tunnels, warranting further research to confirm its effectiveness. [Extracted from the article]

Objective: This study aimed to assess the complication rate during and 24 hours after cryoablation in lung, bone, and soft tissue tumors. Methods: We reviewed complications in a total of 85 consecutive patients who underwent cryoablation using a liquid nitrogen-based system in various lesions between April 2017 and October 2022. There were no liver and renal lesions. Complications were categorized using the Society of Interventional Radiology classification. Results: Eighty-five patients were treated for 96 lesions in the bone (36.4%; 35 of 96), lung (18.8%; 18 of 96), and soft tissue (44.8%; 43 of 96). The primary technical success rate was 97.7% (83 of 85). The total grade 2 and 1 complication rates were 5.2% (5/96) and 20.8% (20/96), respectively. Two patients had asymptomatic pulmonary embolisms incidentally noted at the 24-hour follow-up computed tomography (grade 2). The most frequent complications were simple and hemorrhagic pleural effusions (18.7%; 18 of 96). Lung procedures had the highest complication rate, where 13 patients (72.2%; 13 of 18) reported complications, including 2 cases of symptomatic hydropneumothorax requiring drainage (grade 2) and an additional 2 days of hospital stay. Eight patients (24.2%; 8 of 33) with bone lesions and 4 (9.3%; 4 of 43) with soft tissue lesions experienced complications. Conclusion: Cryoablation using a liquid nitrogen-based system is safe, with only minor complications observed. Advances in knowledge: This study provides data on the safety of liquid nitrogen-based percutaneous cryoablation in tumors located in lung, in bones and in soft tissues. Despite using larger diameter cryoprobes than those typically reported with argon-based system, our experience shows that complications are mostly low and comparable in frequency and severity. [ABSTRACT FROM AUTHOR]

Existing empirical relations used to predict the porosity of gravel beds are mainly derived from laboratory-generated sediment beds with random grain packing. However, such relations could not adequately describe beds with non-random grain arrangements that occur widely in fluvial deposits. In this work, the effect of grain imbrication on gravel-bed porosity has been quantified using beds with variable strengths of imbrication generated by flume experiments. Mono-sized ellipsoids with specific shapes were used in experiments to remove particle size and sorting effects on porosity. Random bed packings were generated by settling of ellipsoids in still water whilst imbricated beds generated under flowing water. Beds were frozen using liquid nitrogen before extraction. A new relatively simple and time-saving workflow was developed to measure the orientation of particles and quantify the degree of grain imbrication in frozen beds from X-ray Computed Tomography images. Beds with the strongest grain fabric display a ca. 0.03 absolute reduction of porosity value on average (8–10% relative reduction) compared to that of random packing for undisturbed beds. Further, results were obtained for beds deposited under still-water conditions subject to disturbance by shaking, to mimic the potential effect of vibrations from currents, waves or other sources in the environment. A reduction in bed porosity of ca. 0.014–0.018 (ca. 5% relative reduction) is observed between beds with the strongest grain fabric and those with random packing that had undergone shaking after deposition. Hence, a significant proportion (> 50%) of the porosity loss observed for imbricated beds may be attributable to tighter packing due to turbulence-related vibrations from the flow. The small decrease in porosity value despite the formation of strong imbrication is considered to be due to the limited improvement in grain organization, as the results show that the flat shape of the ellipsoids and the uniformity of their size promote the formation of a stacking structure under gravity, leading to a similarly highly ordered grain organization in random packings compared to the imbricated packings. [ABSTRACT FROM AUTHOR]

We report the synthesis of the polycrystalline Cu 3 N phase via a diffusion reaction between copper and nitrogen under extreme conditions. Herein, the solid-state diffusion mechanism for the synthesis of the Cu 3 N phase was analyzed. Structural indexing of the new phase was confirmed using the X-ray diffraction technique. Synthesis of the above Cu 3 N phase applying this novel technique is an inexpensive method for the industrial production of the material. The microstructure of the above solid was investigated under a high-resolution scanning electron microscope. [ABSTRACT FROM AUTHOR]

A novel double-impurity doping process for silicon (Si) surfaces was developed, utilizing nanosecond-laser melting of an 11 nm thick gold (Au) top film and a Si wafer substrate in a laser plasma-activated liquid nitrogen (LN) environment. Scanning electron microscopy revealed a fluence- and exposure-independent surface micro-spike topography, while energy-dispersive X-ray spectroscopy identified minor Au (~0.05 at. %) and major N (~1–2 at. %) dopants localized within a 0.5 μm thick surface layer and the slight surface post-oxidation of the micro-relief (oxygen (O), ~1.5–2.5 at. %). X-ray photoelectron spectroscopy was used to identify the bound surface (SiNx) and bulk doping chemical states of the introduced nitrogen (~10 at. %) and the metallic (<0.01 at. %) and cluster (<0.1 at. %) forms of the gold dopant, and it was used to evaluate their depth distributions, which were strongly affected by the competition between gold dopants due to their marginal local concentrations and the other more abundant dopants (N, O). In this study, 532 nm Raman microspectroscopy indicated a slight reduction in the crystalline order revealed in the second-order Si phonon band; the tensile stresses or nanoscale dimensions of the resolidified Si nano-crystallites envisioned by the main Si optical–phonon peak; a negligible a-Si abundance; and a low-wavenumber peak of the Si3N4 structure. In contrast, Fourier transform infrared (FT-IR) reflectance and transmittance studies exhibited only broad structureless absorption bands in the range of 600–5500 cm−1 related to dopant absorption and light trapping in the surface micro-relief. The room-temperature electrical characteristics of the laser double-doped Si layer—a high carrier mobility of 1050 cm2/Vs and background carrier sheet concentration of ~2 × 1010 cm−2 (bulk concentration ~1014–1015 cm−3)—are superior to previously reported parameters of similar nitrogen-implanted/annealed Si samples. This novel facile double-element laser-doping procedure paves the way to local maskless on-demand introductions of multiple intra-gap intermediate donor and acceptor bands in Si, providing related multi-wavelength IR photoconductivity for optoelectronic applications. [ABSTRACT FROM AUTHOR]

This study presents research on the stress distribution characteristics of rock in the bottomhole and the influence laws of various parameters under the impact of liquid nitrogen jet. A multi-field coupled numerical model considering transient flow field, conjugate heat transfer, and nonlinear solid deformation was established to investigate the damage-induced fracturing mechanism of rock under liquid nitrogen jet. The study compares the impact effects of liquid nitrogen jet and water jet on rock and analyzes the variations in the stress field under different parameters. Due to its extremely low temperature, the liquid nitrogen jet creates a strong thermal stress gradient in a short time, significantly increasing the maximum principal stress and Mises stress in the rock compared to a water jet. Solid parameters, particularly the confining pressure and elastic modulus of the rock, have a more significant impact on stress distribution, while fluid parameters such as outlet pressure and fluid temperature have a smaller and more volatile effect. An increase in confining pressure inhibits tensile failure in the rock, while a higher elastic modulus enhances both tensile and shear failure. The initial rock temperature significantly affects the stress distribution, with optimal tensile failure observed at intermediate temperatures. The liquid nitrogen jet achieves a higher maximum velocity and overflow velocity than the water jet, contributing to more effective rock fracturing. The results provide a theoretical basis for the optimization of liquid nitrogen jet drilling parameters, which can help improve drilling efficiency. [ABSTRACT FROM AUTHOR]

Cryogenic liquids such as liquid oxygen and liquid hydrogen are extensively used in many processes and manufacturing industries. In these industries, transferring cryogens via pipelines is a routine phenomenon. As the boiling points and latent heat of cryogens are low, excessive vaporization of these cryogens is innate. Therefore, ensuring that the cryogen reaches the utility in its liquid form is challenging. In the case of liquid hydrogen and liquid helium, the pipelines are jacketed with a high boiling cryogen like nitrogen. The idea is to dump most of the heat into cheap nitrogen to limit the loss of precious hydrogen or helium. From a heat inleak point, maximizing the amount of nitrogen in the jacket is advantageous by choosing large cross‐sectional areas. Also, larger flow cross sections would lower pressure drops and, therefore, lower pumping costs. However, such a choice would add to the mass of the pipeline. An increase in the mass of the pipeline increases the need for better structural support of the pipeline assembly. Therefore, the design of cryogen jackets for limiting heat inleak is a multi‐objective optimization problem. In this work, we model the heat leak into the hydrogen via the nitrogen jacket and the pressure drop of liquid nitrogen, and we find the mass of the pipeline assembly. Then, we optimize the design of nitrogen jackets fitted over hydrogen pipelines. We employ the evolutionary optimization technique, genetic algorithm (GA), to perform this optimization.cryogen; genetic algorithm; heat inleak; liquid hydrogen; optimization. [ABSTRACT FROM AUTHOR]

The cryopreservation of Anthurium andraeanum germplasm resources is extremely important for the production and selection of new varieties. At present, the cryopreservation procedure for the callus of A. andraeanum has not been established. In this study, the leaves of A. andraeanum were used as explants to culture the callus. The cryopreservation procedure of the callus by vitrification was initially established by using the orthogonal experimental method of four factors and three levels in the preculture, loading, and dehydration steps. Furthermore, the vitrification-based cryopreservation was optimized by changing the preculture temperature and loading solution and adding exogenous substances to the plant vitrification solution (PVS2). In this procedure, the callus was precultured at 25 °C for 2 d, and loaded in 50% PVS2 at 25 °C for 60 min. The callus was dehydrated with PVS2 containing 0.08 mM reduced glutathione (GSH) at 0 °C for 60 min. After rapid-cooling in liquid nitrogen for 1 h, it was rapid-warming in a water bath at 40 °C for 90 s and unloaded for 30 min. After 1 d of recovery, the cell relative survival rate of the cryopreserved callus was 64.60%. The results provide a valuable basic and effective method for the long-term conservation of A. andraeanum germplasm resources. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ammonia removal from wastewater by electrooxidation (EO) is an interesting approach because of its efficiency and easy maintenance and operation. In this process, ammonia is oxidized to nitrate or nitrogen gas. Ammonia conversion to the latter is desirable to remove nitrogen from the liquid; however, the influence of several operating parameters on nitrate generation has not been systematically evaluated. Therefore, this work aimed to investigate the effect of current density (200–800 A m−2), chloride concentration (0–10 000 mg L) and initial pH (5–9) on the electrooxidation of an ammonia‐containing solution and the associated generation of nitrate. For this purpose, a laboratory‐scale electrochemical reactor containing two Ti/RuO2 electrodes was used. RESULTS: The results indicated high ammonia removal efficiency – 98% within 150 min at 800 A m−2 and 97% within 240 min at 500 A m−2 – generating around 70 and 102 mg NO3−‐N L−1 under these conditions, respectively. Increasing the chloride concentration from 5000 to 7500 mg L−1 reduces the electrolysis time needed to remove all ammonia from 180 to 150 min. However, with increasing initial chloride concentration, the amount of nitrate generated rose from 69.5 to 135.9 mg N L−1. On the other hand, in the test without chloride, nitrate generation was considerably lower (0–0.61 mg L−1). CONCLUSION: The higher the current density applied, the greater the ammonia removal by EO. Although current density influenced the ammonia oxidation rates, it did not directly affect nitrate formation. The lower the concentration of ammonia in the solution, the more significant was the fraction of nitrate generated. Most of the inlet ammonia was oxidized to nitrogen gas, nitrite was rapidly oxidized to nitrate and higher chloride concentrations enhanced ammonia oxidation. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSCs) are a type of cell capable of regulating the immune system, as well as exhibiting self-renewal and multi-lineage differentiation potential. Mesenchymal stem cells have emerged as an essential source of seed cells for therapeutic cell therapy. It is crucial to cryopreserve MSCs in liquid nitrogen prior to clinical application while preserving their functionality. Furthermore, efficient cryopreservation greatly enhances MSCs' potential in a range of biological domains. Nevertheless, there are several limits on the MSC cryopreservation methods now in use, necessitating thorough biosafety assessments before utilizing cryopreserved MSCs. Therefore, in order to improve the effectiveness of cryopreserved MSCs in clinical stem cell treatment procedures, new technological techniques must be developed immediately. The study offers an exhaustive analysis of the state-of-the-art MSC cryopreservation techniques, their effects on MSCs, and the difficulties encountered when using cryopreserved MSCs in clinical applications. [ABSTRACT FROM AUTHOR]

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Combining cholesterol‐loaded methyl‐β‐cyclodextrin (CD‐CHL) with vitamin E‐loaded methyl‐β‐cyclodextrin (CD‐Vit E) to combat cold shock and oxidative stress during sperm cryopreservation in soybean lecithin extenders remains unexplored. Thus, the current study aimed to investigate the effect of treating bull sperm with CD‐CHL and CD‐Vit E prior to cryopreservation in a soybean lecithin extender. Sperm collected from eight fertile bulls were pooled and split into six aliquots. Five aliquots were treated, in a Tris‐based extender, with CD‐CHL (2 mg/120 × 106 cells/mL) and either 0, 0.5, 1.0, 1.5 or 2 mg CD‐Vit E/120 × 106 cells/mL. The control aliquot was diluted in a Tris‐based extender without further supplementation. After incubation at 22°C for 15 min and addition of a soybean lecithin extender, all aliquots were equilibrated for 2 h at 4°C and then cryopreserved in liquid nitrogen. Computer‐assisted sperm analysis (CASA) was used to explore the different sperm motility parameters, hypo‐osmotic swelling test to determine membrane functionality and fluorescein isothiocyanate‐conjugated Aeachis hypogaea (peanut) agglutinin (FITC‐PNA) to quantify acrosome integrity. The effect of oxidative stress on the sperm membrane was assessed through lipid peroxidation measurement. Compared to control, CD‐CHL alone improved significantly (p < 0.05) all CASA motility parameters, membrane functionality and acrosome integrity of thawed sperm. The membrane functionality was more significantly (p < 0.05) improved when 0.5 mg CD‐Vit E was combined with CD‐CHL. Concerning lipid peroxidation, no significant differences (p > 0.05) in malondialdehyde (MDA) levels were registered between groups. In conclusion, the combination of CD‐CHL and CD‐Vit E demonstrated a significant positive effect on the cryopreservation of bull sperm in a soybean lecithin extender. [ABSTRACT FROM AUTHOR]

Liquid nitrogen is the most common refrigerant adopted in the artificial ground freezing (AGF) method for the rapid freezing of soil. However, the relatively high price of liquid nitrogen demands the reuse of liquid nitrogen in AGF, which utilizes partially gasified liquid nitrogen after an initial injection. This study investigated the reusability of liquid nitrogen in AGF by performing a field experiment. Temperatures of the ground were monitored near the sub-freezing pipes installed 1 m away from the main freezing pipes, where liquid nitrogen was initially injected. A frozen wall having a thickness of 1 m was formed between two sub-freezing pipes after 5 days of injecting liquid nitrogen into the main freezing pipes. Furthermore, the lowest temperature of − 12 °C measured in the sub-freezing pipe implied that the temperature of nitrogen after circulating through the main freezing pipe was sufficiently low to freeze the surrounding soil formation. The freezing rate, elapsed time for freezing, and freezing duration evaluated from the monitored temperature data also demonstrated the promising potential of reusing liquid nitrogen in AGF for saturated silty deposits. [ABSTRACT FROM AUTHOR]

Persistent luminescence (PersL) phosphors have garnered significant attention for their extensive applications in various fields. It is regrettable that these PersL phosphors typically possess deep traps. At low temperatures (LT), energy stored in the trap cannot be released to the luminescent centers through thermal de‐trapping, thereby causing these PersL phosphors to lose their PersL characteristics in LT. Currently, there is little research on LT PersL phosphors, and multicolor LT PersL in a single host material has not been reported. In this work, multicolor LT PersL is achieved in a single host material by modifying the emission center. Remarkably, an ultra‐shallow trap with a depth of 0.23 eV is discovered in the Cs2NaLuCl6:5%Ln3+ phosphors, which is essential for achieving PersL at 77 K. First‐principles calculations indicate that the ultra‐shallow trap in Cs2NaLuCl6:5%Ln3+ is caused by the distortion of [NaCl6] octahedron in the phosphors. These findings provide new perspectives into X‐ray‐induced trap generation and offer valuable insights for designing multicolor PersL phosphors for LT applications. [ABSTRACT FROM AUTHOR]

In this manuscript, we report on the synthesis of a polynitrogen material from a potassium azide precursor using nanosecond-pulsed spark discharge plasma in liquid nitrogen. The polynitrogen material was characterized using Raman and Fourier transform infrared (FTIR) spectroscopy and identified as K2N6, with planar N6 rings and K- ions that have P6/mmm symmetry. An analysis of the mechanism behind such a transformation shows the importance of direct plasma–chemical effects in polymerization, while the crystal structure changes are believed to be due to plasma-emitted radiation in the ultraviolet range. [ABSTRACT FROM AUTHOR]

Surface quality, machining efficiency, and tool life are all significantly impacted by tool wear in metal cutting machining. Research priorities and areas of focus in tool wear are shifting as intelligent machining becomes the norm. Unfortunately, there are currently no acknowledged most effective ways for analyzing tool based on the energy signals specially in the machining of titanium and its alloys. In the present work, the titanium machining was performed under different lubrication conditions such as dry, minimum quantity lubrication (MQL), liquid nitrogen and hybrid, etc. Then, the spectrograms are used to transform the acquired energy data into time–frequency features. Starting with a set of randomly generated hyper parameters (HPs), the long short-term memory (LSTM) model is fine-tuned using sine cosine algorithm (SCA) with loss serving as the fitness function. The confusion matrix provides additional validation of the 98.08% classification accuracy. Additional evaluations of the suggested method's superiority include its specificity, sensitivity, F1-score, and area under the curve (AUC). [ABSTRACT FROM AUTHOR]

Tetrataenite is a promising candidate for rare earth-free permanent magnets due to its low cost and intrinsic magnetic properties. This work investigates the effect of combined milling at liquid nitrogen temperatures (cryomilling) and the addition of carbon as an interstitial element for promoting the formation of tetrataenite. Crystal structure, microstructure, and magnetic properties are investigated to understand the influence of mechanical processing and compositional modifications. No unambiguous evidence of the ordered phase of tetrataenite is found in the structural characterization. However, using Scanning Transmission Electron Microscopy (STEM) and powder X-ray diffraction (PXD) analyses, the occurrence of both twinning and stacking faults resulting from the high-energy milling process is observed, which is a relevant factor for identifying tetrataenite in FeNi alloys. The probability of a stacking fault and twinning occurring for a carbon-free FeNi sample before annealing is found to be 2% and 1.4%, respectively. After annealing, the stacking fault probability decreased to 1.2%, while that of twinning was 1.4%. By increasing the carbon concentration to 5 at.%, the stacking faults and twinning probabilities decrease slightly to 1.2% and 1.3%, respectively. The occurrence of stacking faults combined with small crystallite sizes was a hindering factor in identifying the presence of tetrataenite. [ABSTRACT FROM AUTHOR]

Autophagosome biogenesis is a complex process orchestrated by dynamic interactions between Atg (autophagy-related) proteins and characterized by the turnover of specific cargoes, which can differ over time and depending on how autophagy is stimulated. Proteomic analyses are central to uncover protein-protein interaction networks and when combined with proximity-dependent biotinylation or proximity labeling (PL) approaches, they also permit to detect transient and weak interactions. However, current PL procedures for yeast Saccharomyces cerevisiae, one of the leading models for the study of autophagy, do not allow to keep temporal specificity and thus identify interactions and cargoes at a precise time point upon autophagy induction. Here, we present a new ascorbate peroxidase 2 (APEX2)-based PL protocol adapted to yeast that preserves temporal specificity and allows uncovering neighbor proteins by either western blot or proteomics. As a proof of concept, we applied this new method to identify Atg8 and Atg9 interactors and detected known binding partners as well as potential uncharacterized ones in rich and nitrogen starvation conditions. Also, as a proof of concept, we confirmed the spatial proximity interaction between Atg8 and Faa1. We believe that this protocol will be a new important experimental tool for all those researchers studying the mechanism and roles of autophagy in yeast, but also other cellular pathways in this model organism. Abbreviations: APEX2, ascorbate peroxidase 2, Atg, autophagy-related; BP, biotin phenol; Cvt, cytoplasm-to-vacuole targeting; ER, endoplasmic reticulum; LN2, liquid nitrogen; MS, mass spectrometry; PAS, phagophore assembly site; PL, proximity labeling; PE, phosphatidylethanolamine; PPINs, protein-protein interaction networks; PPIs, protein-protein interactions; RT, room temperature; SARs, selective autophagy receptors; WT, wild-type. [ABSTRACT FROM AUTHOR]

To improve the efficiency of coalbed methane and recoverability of reservoirs, enhanced fracturing technology is usually required to improve the low porosity and permeability status of coal reservoirs. As a feasible method for strengthening permeability, microwave–LN2 freeze–thaw (MLFT) cycles modify the microscopic pore structure of coal through the coupled effect of temperature stress changes, phase change expansion, and fatigue damage. 1H nuclear magnetic resonance combined with fractal dimension theory was used to characterize quantitatively the pore system and geometric features of coal. The geometric fractal model constructed using the T2 spectrum indicates that the fractal dimensions Dp and De have high fitting accuracy, demonstrating that percolation and effective pores exhibit good fractal characteristics. Dp and De are correlated negatively and positively, respectively, with the cyclic parameters. The relevance analysis shows that the NMR fractal method can reflect the pore–fracture heterogeneity of coal, which has a significant effect on the percentage of fluid migration space. This study reveals that MLFT cycles have significant enhancement effects on promoting the extension of multi-type pores structures within the coal matrix, as well as the connectivity and permeability of cracks. [ABSTRACT FROM AUTHOR]

Liquid nitrogen (LN2) fracturing has various advantages, such as low reservoir damage, minimal environmental impact, and excellent permeability. In this study, the cracking pattern and damage evolution characteristics of bedded coal subjected to LN2 fracturing were investigated. The deterioration features of the mechanical parameters and failure mechanisms were examined in a comparable manner using Brazilian splitting tests. Additionally, the damage characteristics of bedded coal during LN2 fracturing were explored. The results indicated that LN2 cooling promoted the development of thermal cracks, consequently reducing the effective bearing capacity of the coal. Randomly distributed thermal cracks actively contributed to macroscopic crack propagation, increasing the proportion of shear cracks and the complexity of the fracture surface. Different bedding angles led to distinct failure modes, significantly impacting the proportion of shear cracks and the fracture surface complexity. Moreover, the bedding planes constantly influenced the propagation direction of the fracturing cracks, resulting in a macroscopic damage zone that expanded preferentially at the weak bedding planes with the borehole at the center. With increasing bedding angles, both the degree and rate of damage of coal decreased sequentially. Consequently, it was feasible to employ LN2 fracturing in low-permeability reservoirs along the bedding planes, facilitating swift and efficient reservoir fracturing. [ABSTRACT FROM AUTHOR]

Evolution of nitrogen under shock compression up to 100 GPa is revisited via molecular dynamics simulations using a machine-learned interatomic potential. The model is shown to be capable of recovering the structure, dynamics, speciation, and kinetics in hot compressed liquid nitrogen predicted by first-principles molecular dynamics, as well as the measured principal shock Hugoniot and double shock experimental data, albeit without shock cooling. Our results indicate that a purely molecular dissociation description of nitrogen chemistry under shock compression provides an incomplete picture and that short oligomers form in non-negligible quantities. This suggests that classical models representing the shock dissociation of nitrogen as a transition to an atomic fluid need to be revised to include reversible polymerization effects. [ABSTRACT FROM AUTHOR]

Water jet impact technology has more advantages in environmental protection, safety and quality. This paper innovatively puts forward the new technology of temperature–hydrodynamic coupling effect rock breaking, which can fully utilize the water jet energy and effectively improve the mining and excavation capacity of granite, especially suitable for high-temperature rocks. Taking the common granite in the actual project as an example, the mechanical test and water jet impact test are carried out to study and analyze the temperature–water jet coupling effect. Rock-breaking technology, acoustic emission technology, image recognition technology and nuclear magnetic resonance technology are used to analyze the mechanism of the temperature–water jet coupling effect, supplemented with numerical simulation to verify and analyze. The test results show that: under the action of temperature–hydrodynamic coupling, the granite crushing is more obvious, the degree of influence of liquid nitrogen impact time 120 s > 180 s > 240 s > 300 s > 60 s, and the crushing efficiency is improved by 117%; through numerical simulation to analyze the comprehensive damage factors, the temperature–hydrodynamic coupling effect produces a large number of minor damages in the internal granite; analyzing the stress characteristics of granite. Under the effect of temperature–hydrodynamic coupling, granite is mainly subjected to tensile damage, thus generating cracks to promote granite crushing. The results of the study provide theoretical guidance for practical engineering. [ABSTRACT FROM AUTHOR]

We study properties of nitrogen at high pressure and temperature (100–120 GPa, 2000–3000 K) where molecular and polymeric phases compete both in solid and liquid phase. We employ ab initio MD simulations with the SCAN functional and study the pressure-induced polymerization in liquid nitrogen for system sizes up to 288 atoms in order to reduce finite-size effects. The transition is studied upon both compression and decompression, and at 3000 K, it is found to take place between 110 and 115 GPa, coming close to experimental data. We also simulate the molecular crystalline phase close to the melting line and analyze its structure. We show that the molecular crystal in this regime is highly disordered, in particular, due to pronounced orientational and also translational disorder of the molecules. Its short-range order and vibrational density of states are very close to those of the molecular liquid revealing that the system likely represents a plastic crystal with high entropy. [ABSTRACT FROM AUTHOR]

Aspergillus species are known to be very important in human and domestic animal health. Aspergillus species commonly cause severe systemic and skin infections, as well as allergic lung diseases. With the development of PCR techniques, these methods are used to identify and diagnose fungi. DNA extraction from Aspergillus species is difficult because the fungal cell wall structure is very durable and complex. Fungal DNA extraction methods containing proteinase K and liquid nitrogen are widely used to break down the cell wall. However, these methods cause DNA loss during the extraction in Aspergillus species. In this study, on the contrary, the commonly used DNA extraction by means of ammonium hydroxide, which is generally used to break down chitin in DNA extraction of ticks and plants, is used. The efficiency of the cell wall lysis method from A. flavus with ammonium hydroxide was compared with methods containing proteinase K and liquid nitrogen. For this purpose, DNA extraction of A. flavus was tried using three different methods. As a result, the cell wall of A. flavus was lysed using ammonium hydroxide in this study. The obtained DNA’s quality, concentration, and PCR performance were sufficient. This method has been evaluated as a faster, more straightforward, and more economical alternative.

Phyllostachys praecox shoots were frozen using liquid nitrogen at –60, –90 or –120 ℃ to an internal temperature of –18 ℃, or frozen at –90 ℃ to an internal temperature of –6, –12 or –18 ℃, vacuum-packed and stored in a freezer at –18 ℃ for 24 weeks. In order to analyze the effect of liquid nitrogen freezing on physiological and biochemical characteristics of P. praecox shoots during frozen storage, L-phenylalanine ammonialyase (PAL) and peroxidase (POD) activities, total phenolic content, relative electrical conductivity, and water state were measured and ice crystal structure and cell morphology were observed. The results showed that with increasing freezing time, the PAL and POD activities, total phenolic content, and peak area of free water in all six groups decreased significantly (P 0.05). The PAL and POD activities and relative conductivity of P. praecox shoots frozen at –6 ℃ were higher than those frozen at –12 and –18 ℃, and the size of ice crystals was smaller and the degree of cell damage was greater in P. praecox shoots frozen at –6 ℃ than at –12 and –18 ℃. The difference between P. praecox shoots frozen at –12 and –18 ℃ was not significant (P > 0.05). Collectively, these findings indicated that the most suitable liquid nitrogen freezing conditions of P. praecox shoots are –90 and –12 ℃ for freezing and internal temperature, respectively.

Glass formation and the nature of the chemical interaction in the As2Se3–Tl2Te3 system were studied by differential-thermal (DTA), X-ray phase (XRD), microstructural (MSA) analysis. Based on the performed experiments T-x phase diagram is constructed. It is established that the phase diagram of the system is a partially quasi-binary section of the quaternary system Tl,As//Se,Te. Eutectic equilibrium and peritectic transformation process occur in the system. When the ratio of As2Se3 and Tl2Te3 components is 1:1, a new quaternary compound Tl2As2Se3Te3 is formed. It has been established that the Tl2As2Se3Te3 compound melts with an open maximum at 568 K and crystallizes in a hexagonal symmetry. In the system, under normal cooling, the glass formation area reaches −80 mol.% Tl2Te3, and in the mode of quenching in liquid nitrogen up to −100 mol.% T12Te3. The photoelectric properties of glassy alloys (As2Se 3 ) 1 − x (Tl2Te 3 ) x (x = 0. 0 1 ; 0.3; 0.05) have been studied. Depending on the Tl2Te3 concentration of the system, the observed changes in the photoelectric properties and calculated parameters are presented. [ABSTRACT FROM AUTHOR]

Nuclear energy, as an important component of the power system, has become a key focus of future energy development research. Various equipment and pipelines in nuclear power plants require regular inspection, maintenance, and repair. The pipelines in nuclear power plants are typically large, necessitating a device that can locally isolate sections of the pipeline during maintenance operations. Ice plug freezing technology, an economical and efficient method for maintaining and replacing equipment without shutdown, has been widely applied in nuclear power plants. The structure of the ice plug jacket, a type of low-temperature jacket heat exchanger, affects the flow path of the working fluid within the jacket and consequently impacts heat transfer. This study utilizes Computational Fluid Dynamics (CFD) to establish five types of jacket structures: standard, center-offset (center-in, side-out), helical, helical fin, and labyrinth. The effects of different structures on the freezing characteristics of ice plugs are analyzed and compared. The research indicates that the labyrinth jacket enhances the heat transfer performance between liquid nitrogen and the liquid inside the pipe, forming a larger ice layer at the same liquid nitrogen flow rate. Additionally, the standard jacket has the shortest sealing time at high liquid nitrogen flow rates. [ABSTRACT FROM AUTHOR]

This study examines the impact of high-pressure torsion (HPT) processing at various temperatures on the precipitation behavior of Cu-Cr alloys. The introduction of defects through HPT is observed to promote the precipitation of Cr atoms. Unlike the traditional large-scale precipitation that typically occurs around 400 °C, HPT can induce the precipitation of solute atoms even at room temperature. Furthermore, the temperature at which HPT is performed significantly influences the behavior of the precipitated phase during subsequent aging, ultimately affecting the alloy's overall properties. At elevated temperatures (ETs) and room temperature (RT), Cr atoms tend to aggregate, forming Guinier–Preston (GP) zones or precipitates, which coarsen into incoherent precipitates after annealing. In contrast, when HPT is conducted at liquid nitrogen temperature (LNT), Cr atoms are retained in their original positions, leading to the formation of uniformly distributed, high-density small precipitates post-annealing. This phenomenon results in superior properties for HPT-LNT-treated samples, evidenced by a microhardness of 191.8 ± 3.2 HV and an electrical conductivity of 84.6 ± 1.8% IACS. [ABSTRACT FROM AUTHOR]

Fungi occupy important environmental, cultural, and socioeconomic roles. However, biological research of this diverse kingdom has lagged behind that of other phylogenetic groups. This is partially the result of the notorious difficulty in culturing a diverse array of filamentous fungal species due to their (i) often unpredictable growth, (ii) unknown preferences for culturing conditions, and (iii) long incubation times compared with other microorganisms such as bacteria and yeasts. Given the complexity associated with concurrently culturing diverse fungal species, developing practical methods for preserving as many species as possible for future research is vital. The widely accepted best practice for preserving fungal tissue is the use of cryogenic biobanking at −165 C, allowing for the preservation and documentation of stable genetic lineages, thus enabling long-term diversity-centered research. Despite the extensive literature on fungal cryopreservation, substantial barriers remain for implementation of cryogenic biobanks in smaller mycological laboratories. In this work, we present practical considerations for the establishment of a fungal culture biobank, as well as provide evidence for the viability of 61 fungal genera in cryogenic storage. By providing a pragmatic methodology for cryogenically preserving and managing many filamentous fungi, we show that creating a biobank can be economical for independently owned and operated mycology laboratories, which can serve as a long-term resource for biodiversity, conservation, and strain maintenance. [ABSTRACT FROM AUTHOR]

• LNF exhibited a high freezing rate and contributed to small ice crystal forming. • LNF maintained WHC and shear force of Monopterus albus. • LNF alleviated myofibrillar protein denaturation of Monopterus albus. • LNF at −110 °C is more suitable for Monopterus albus than LNF at −50 °C and −80 °C. Monopterus albus is highly susceptible to spoilage due to high protein and moisture contents while frozen storage can effectively prolong the shelf-life. To study the effect of liquid nitrogen freezing (LNF) on quality, microstructure of ice crystal and muscle fiber, and physicochemical properties of proteins, Monopterus albus was frozen at -20 °C by refrigerator (RF, control), -50 °C, -80 °C, and -110 °C by LNF, respectively. The -110 °C LNF exhibited the highest freezing rate among four groups, contributing to the formation of small ice crystals with more uniform distribution and alleviating the damage to muscle fiber. In -110 °C LNF group, protein secondary structure changed relatively subtle, resulting in high protein solubility, Ca2+-ATPase activity, and total sulfhydryl content, as well as low surface hydrophobicity and disulfide bond content. LNF retarded the rise of TVB-N value, prevented the loss of immobilized and free water, and maintained water holding capacity and shear force. In conclusion, -110 °C LNF was recommended a promising freezing process for frozen Monopterus albus due to less alteration of quality and alleviation of protein denaturation. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: In contrast to traditional impact-based testing, the Dynamic Tensile Tear Test (DT3) has shown great potential to characterise high-grade pipeline steels as it mimics the in-field pipeline conditions. However, material characterisation using the DT3 method has only been performed at room temperature and lower-shelf characterisation has not yet been investigated. Objective: This study investigates a solution to perform low-temperature characterisation and analyse dynamic brittle fracture behaviour using the DT3 setup. Methods: A large-surface spray cooling system using liquid nitrogen was constructed and implemented onto the DT3 system. Cooling performance and temperature uniformity were assessed using thermocouples across a large surface area up to 412 cm2 (2 × 206 cm2). Numerical validation was performed through Finite Element (FE) analysis using the Modified Bai-Wierzbicki (MBW) material model. A combined stress–strain criterion was used to take into account cleavage failure. Results: Temperatures down to -125 °C were reached using the spray cooling system and a fracture tests was performed at -80 °C. The obtained data and resulting fracture surface indicated clear brittle fracture behaviour. An average crack velocity of 152 m/s was measured, which is in the same order of magnitude associated with crack velocities observed in large-scale testing. Conclusions: The constructed spray cooling system proved to be capable of cooling a large volume down to cryogenic temperatures while achieving acceptable temperature uniformity. Lower-shelf characterisation of X70 grade pipeline steel was achieved using the DT3 method and a good correlation was obtained between numerical data and experimental observations. [ABSTRACT FROM AUTHOR]

Fish swim bladder (FSB) is a type of traditional nutraceutical, but the lack of high-quality drying methods limits its premium market development. In order to obtain optimal-quality dried FSBs from Chinese longsnout catfish, the effects of liquid nitrogen pre-freezing (LNF) and drying on the physical properties and flavor of FSB were evaluated. Four methods were used for FSB drying, including natural air-drying (ND), hot-air-drying (HD), LNF combined with freeze-drying (LN-FD), and LNF combined with HD (LN-HD). Color, collagen content, rehydration ratio, textural properties, and flavor characteristics (by GC-IMS, E-nose, and E-tongue) were measured to clarify the differences among four dried FSBs. The results showed that ND cannot effectively remove moisture from FSB as the final product showed a stronger sourness in taste. HD led to a decrease in the collagen content and the collapse of the fiber structure in FSB. Compared to HD, LN-HD showed a higher collagen content (0.56 g/g) and a different flavor fingerprint. FSB treated by LN-FD had better physical qualities in terms of an attractive color, a high collagen content (0.79 g/g), low shrinkage, a higher rehydration ratio (2.85), and a soft texture, while also possessing richer characteristic flavors. The application of LN-FD may help the optimization of the nutrition level, rehydration ability, mouthfeel, and flavor of dried FSB. [ABSTRACT FROM AUTHOR]

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This study examines a rare case of frostbite on the hands caused by liquid nitrogen, focusing on the scar maturation process. Frostbite is typically less prone to abnormal scarring compared to burns, and this report contrasts the differences in scar maturation between the two. A 31-year-old male hospital employee sustained first- to second-degree frostbite on his gloved hands from a 20-s exposure to liquid nitrogen while changing a cylinder. Conservative treatment was applied, and the patient was monitored for 9 months. The deeply affected area took 50 days to epithelialize but healed without hypertrophic scarring. A mild extension contracture was noted in the distal interphalangeal joint of the right index finger, but the skin remained supple and soft. Incidents of liquid nitrogen-induced frostbite are uncommon, with only 14 cases reported in PubMed previously. In frostbite, the wound healing involves a slow replacement of damaged connective tissue, which acts as an internal splint, reducing wound contraction. This contrasts with burns, where rapid connective tissue replacement occurs, often leading to significant wound contraction due to the presence of myofibroblasts in granulation tissue. In the presented case, the slow healing process and minimal wound contraction led to mature scarring without abnormalities, underlining a distinctive healing trajectory in frostbite injuries compared to burns. [ABSTRACT FROM AUTHOR]

The butt joints of AA2099-T86 alloy were prepared by friction stir welding process under four different environments, i.e. conventional (C-FSW), liquid nitrogen (LN-FSW), ultrasonic vibration welding (U-FSW), and ultrasonic vibration with liquid nitrogen (ULN-FSW). The welding tool rotational speed of 650 rpm and tool traverse speed of 80 mm/min were fixed for all experiments. The microstructural characterization of the welded samples is examined with optical microscopy, SEM, and XRD. Higher tensile strength and microhardness were obtained in the ULW-FSW welded samples. The ultrasonic vibrations promote plastic deformation and material mixing, increasing the dislocation density and improving the weld strength. In addition, liquid nitrogen restricts the grain size and dissolution of strengthening precipitates due to the rapid welding cooling rate, resulting in higher hardness. Comparative analysis of weld joint efficiencies revealed that the ULN-FSW welded sample achieved an impressive efficiency of 87.12%. In contrast, U-FSW, LN-FSW, and C-FSW displayed efficiencies of about 86.17%, 83.01%, and 74%, respectively. [ABSTRACT FROM AUTHOR]