Temperature-dependent Enhancement Research Articles

Temperature-dependent microscopic deformation mechanisms and performance enhancement prospects in high-cycle fatigue of nickel-based single crystal superalloys

Temperature-dependent microscopic deformation mechanisms and performance enhancement prospects in high-cycle fatigue of nickel-based single crystal superalloys

Construction of 2D zinc(II) MOFs with tricarboxylate and N-donor mixed ligands for multiresponsive luminescence sensors and CO2 adsorption.

The solvothermal reactions of ZnCl2·6H2O, benzene-1,3,5-tribenzoic acid (H3btb), and N-heterocyclic ancillary imidazole (Im) or aminopyrimidine (a mp) ligands led to the creation of two-dimensional (2D) zinc(II) based metal-organic frameworks (MOFs), (Me2NH2)2[Zn2(btb)2(Im)2]·2DMF·3MeOH (1) and (Me2NH2)2[Zn2(btb)2(amp)]·H2O·2DMF·MeOH (2). The btb3- ligands in 1 and 2 form an anionic 2D layered structure with a (63) honeycomb (hcb) topology by linking to Zn(II) centres through their carboxylate groups. The incorporation of N-heterocyclic auxiliary ligands Im and amp into the hcb nets resulted in the formation of a 2D hydrogen-bonded and covalently pillared bilayer structure featuring two-fold interpenetrating networks. Each of these networks consists of small channels that are occupied by Me2NH2 cations and solvent molecules. Both 1 and 2 emit blue luminescence emissions in the solid state at room temperature and exhibit a great selectivity and sensitivity for the detection of acetone and multiple heavy metal ions including Hg2+, Cu2+, Fe2+, Pb2+, Cr3+, and Fe3+ ions. At 1 bar, activated 1 and 2 demonstrate moderate capacities for adsorbing CO2 at room temperature, with a preference for CO2 over N2. Notably, at higher pressures (up to 20 bar), their activated samples 1 and 2 show a temperature-dependent enhancement of CO2 uptake while retaining good stability.

Spin-flop phase transitions in vdW antiferromagnet MnPSe3

Two-dimensional (2D) van der Waal (vdW) magnets are gaining significance in exploring fundamental condensed matter physics and developing cutting-edge technologies. Here, we report the structural and magnetic properties of the antiferromagnetic semiconductor MnPSe3 crystal. Intriguing magnetic behaviors and the strong anisotropy of the bulk crystal have been investigated through temperature-dependent magnetization studies along with the observation of Néel temperature at TN=70±2 K. At temperatures below TN, the bulk MnPSe3 exhibits field-induced spin-flop phase transitions with a spin-flop field (HSF) of nearly 8 kOe at 5 K. These transitions are evidenced from isothermal magnetization measurements conducted at low temperatures. Moreover, temperature-dependent enhancement in HSF was also studied. Our findings motivate the exploration of intrinsic magnetic interactions in 2D MnPSe3 and incorporating it into functional vdW heterostructures and devices.

Comprehensive risk assessment of the inhalation of plasticizers from the use of face masks

Disposable masks, formed mainly from polymers, often incorporate various chemical additives to enhance their performance. These additives, which include plasticizers, may be released during mask usage, presenting a novel source of human exposure to these compounds. In this study, the presence of 16 organophosphate esters (OPEs), 11 phthalates, and four alternative plasticizers, in four various types of face masks, were studied, as well as their release during simulated mask use (artificial laboratory conditions). Total plasticizer concentrations exhibited minimal variation across different mask types, with mean values of 7.27 µg/face mask for surgical, 8.61 µg/face mask for reusable, 11.0 µg/face mask for KN-95, and 13.9 µg/face mask for FFP2 masks. To explore plasticizer release behavior, inhalation experiments were conducted under different conditions. The findings revealed a significant temperature-dependent enhancement in plasticizer release from masks, subsequently increasing human inhalation exposure. The inhalation experiments showed variation in the release percentages, ranging from 0.1 to 95 %, depending on the specific compound and mask type. Notably, OPEs exhibited a mean release percentage of 1.0 %, similar to phthalates, which showed a 1.2 % release. Although alternative plasticizers were less frequently released, they still presented a notable percentage of release of 4.1 %. Daily intake estimations via inhalation ranged from 0.01 to 9.04 ng/kg body weight (bw)/day for these additives. Using these estimations, carcinogenic and non-carcinogenic risks associated with this exposure to these compounds were evaluated. All calculated values for the specific compounds studied in this paper remained below the established threshold limits. However, they do represent an additional exposure pathway that, when considered alongside other more predominant routes such as indoor/outdoor inhalation, dermal absorption, and dietary intake, makes the total exposure worthy of consideration.

Tailoring Phase Transition of Mo-S-Te Ternary System using Heat-Driven Process for Target Functionalities

Although structural engineering and phase modulation of transition metal dichalcogenides (TMDs) can be used to implement high-performance optoelectronic devices or energy cells, their expandability combined with individualized optimization for diverse applications using limited TMD materials is still challenging. Herein, we suggest an intriguing strategy to control the target functionalities of the Mo-S-Te ternary system using heat-driven crystallographic selection. The structure and phase alteration of the Mo-S-Te system can be effectively governed by modulating the thermal decomposition temperature, as evidenced by comprehensive spectroscopic and microscopic evaluations. The dual eligibility of the Mo-S-Te ternary system was validated by ascertaining the temperature-dependent selective enhancement of the optoelectronic properties or photoelectrochemical (PEC) performance as compared with those of bare MoS2. The Mo-S-Te synthesized at 300 °C exhibited superior photoresponse dynamics across various wavelengths, indicating its potential for advanced photodetection applications. In field of PEC, Mo-S-Te synthesized at 500 °C was highlighted as a promising photocathode material, offering enhanced PEC reactivity and stability. This study suggests the importance of material characteristics tailored to the synthetic conditions for target applications, which is a promising path to for the expansion of applicability in various areas using a simple approach that utilizes a limited range of TMD materials.

Temperature-dependent augmentation of ciliary motility by the TRP2 channel in Chlamydomonas reinhardtii.

Temperature is a critical factor for living organisms. Many microorganisms migrate toward preferable temperatures, and this behavior is called thermotaxis. In this study, the molecular and physiological bases for thermotaxis are examined in Chlamydomonas reinhardtii. A mutant with knockout of a transient receptor potential (TRP) channel, trp2-3, showed defective thermotaxis. The swimming velocity and ciliary beat frequency of wild-type Chlamydomonas increase with temperature; however, this temperature-dependent enhancement of motility was almost absent in the trp2-3 mutant. Wild-type Chlamydomonas showed negative thermotaxis, but mutants deficient in the outer or inner dynein arm showed positive thermotaxis and a defect in temperature-dependent increase in swimming velocity, suggesting involvement of both dynein arms in thermotaxis.

Impact of temperature on the binding interaction between dsDNA and curcumin: An electrochemical study

In this study, we investigated the binding mode between double-stranded deoxyribonucleic acid (dsDNA) and curcumin (CU) using differential pulse voltammetry (DPV), UV–Vis spectroscopy, and molecular docking. By employing these techniques, we predicted the binding within the minor groove region of dsDNA and CU. Significantly, we employed electrochemistry, specifically cyclic voltammetry (CV), to explore the temperature effect on the dsDNA and CU binding. To the best of our knowledge, this is the first study to utilize electrochemical methods for investigating the temperature-dependent behavior of this binding interaction. Our findings revealed temperature-dependent variations in the binding constants: 2.42 × 103 M−1 at 25 °C, 4.26 × 103 M−1 at 30 °C, 5.44 × 103 M−1 at 35 °C, 6.29 × 103 M−1 at 40 °C, and 7.52 × 103 M−1 at 45 °C. Notably, the binding constant exhibited an increasing trend with elevated temperatures, indicating a temperature-dependent enhancement of the binding interaction.

Temperature-directed fluorescent switchable nanoparticles based on P3OT–PNIPAM nanogel composite

Poly(N-isopropylacrylamide) (PNIPAM) is a unique stimuli-responsive material that exhibits a lower critical solution temperature (LCST). Owing to this characteristic temperature-dependent behavior, PNIPAM has found extensive utilization as an active material in various applications, including sensors, drug delivery, and cellular imaging. Herein, we demonstrate temperature-directed fluorescent switchable nanoparticles based on poly(3-octylthiophene-2,5-diyl) (P3OT) nanoaggregate-embedded PNIPAM nanogel composites (POPNs) featuring different crosslinker contents. The amount of P3OT loading in the nanogel composites can be gradually controlled by varying the crosslinking density of the PNIPAM matrix; this may be attributable to the efficient entrapment of P3OT nanoaggregates in case of a dense polymeric network with the increase in crosslinking density. POPNs exhibit dramatic temperature-dependent fluorescence enhancement (by a factor of 2.11). This is based on the environmental changes affecting fluorescent P3OT chains at temperatures below and above the LCST of the PNIPAM matrix. Based on this temperature-directed fluorescent switching capability, POPN could find potential applications in various fields, including biomedical imaging and sensors.

A photoactive injectable antibacterial hydrogel to support chemo-immunotherapeutic effect of antigenic cell membrane and sorafenib by near-infrared light mediated tumor ablation.

Intravenously administered nanocarriers suffer from off-target distribution, pre-targeting drug leakage, and rapid clearance, limiting their efficiency in tumor eradication. To bypass these challenges, an injectable hydrogel with time- and temperature-dependent viscosity enhancement behavior and self-healing property are reported to assist in the retention of the hydrogel in the tumor site after injection. The cancer cell membrane (CCM) and sorafenib are embedded into the hydrogel to elicit local tumor-specific immune responses and induce cancer cell apoptosis, respectively. In addition, hyaluronic acid (HA) coated Bi2S3 nanorods (BiH) are incorporated within the hydrogel to afford prolonged multi-cycle local photothermal therapy (PTT) due to the reduced diffusion of the nanorods to the surrounding tissues as a result of HA affinity toward cancer cells. The results show the promotion of immunostimulatory responses by both CCM and PTT through the release of inflammatory cytokines from immune cells, which allows localized and complete ablation of the breast tumor in an animal model by a single injection of the hydrogel. Moreover, the BiH renders strong antibacterial activity to the hydrogel, which is crucial for the clinical translation of injectable hydrogels as it minimizes the risk of infection in the post-cancer lesion formed by PTT-mediated cancer therapy.

Anomalous Optical Properties of KTN:Li Ferroelectric Supercrystals.

We report a spectroscopic investigation of potassium-lithium-tantalate-niobate (KTN:Li) across its room-temperature ferroelectric phase transition, when the sample manifests a supercrystal phase. Reflection and transmission results indicate an unexpected temperature-dependent enhancement of average index of refraction from 450 nm to 1100 nm, with no appreciable accompanying increase in absorption. Second-harmonic generation and phase-contrast imaging indicate that the enhancement is correlated to ferroelectric domains and highly localized at the supercrystal lattice sites. Implementing a two-component effective medium model, the response of each lattice site is found to be compatible with giant broadband refraction.

Ultrahigh piezoelectric strain in lead-free BiFeO3-BaTiO3 ceramics at elevated temperature

Lead-free Sm-modified 0.67Bi 1.03 FeO 3 -0.33BaTiO 3 ceramics system was studied systematically and a phase diagram was developed based on crystal structure and electromechanical properties. The Sm 3+ modification on Bi 3+ -site can change the long-range ferroelectric order of the rhombohedral (R) and tetragonal (T) mixed-phase to the short-range relaxor ferroelectric order with a cubic-like phase. For x = 0.01 composition, simultaneously excellent static and dynamic piezoelectric coefficients ( d 33 = 275 pC/N and d 33 * = 350 pm/V) with a high Curie temperature ( T C = 470 °C) were achieved near the morphotropic phase boundary between the R and T phases. Additionally, the room temperature d 33 * (554 pm/V) for x = 0.03 composition significantly improved to 1030 pm/V at 125 °C. The enhanced piezoelectric strain performance at the crossover boundary of the normal and relaxor ferroelectric is probably related to the local structure heterogeneity due to chemical modification and reversibly phase transition after the removal of the applied electric field. However, the temperature-dependent enhancement in piezoelectric strain originates from thermally activated domain switching. The investigated ceramics system shows a good connection between the crystal structure changes with electromechanical properties. This work provides a new paradigm for designing a new lead-free green energy material for high-temperature piezoelectric applications. • Maximum d 33 ∼ 275 pC/N and high T C ∼ 460 °C was obtained at the MPB. • Highest d 33 * = 554 pm/V were achieved at 25 °C and 1030 pm/V at 125 °C. • A phase diagram was developed for the Sm-doped BF-BT ceramics.

The people behind the papers - Phanu Serivichyaswat, Kai Bartusch and Charles Melnyk.

Although botanists and horticulturalists often use warm nurseries to increase graft success, little was known about the role of temperature in promoting wound healing and tissue regeneration. Now, a new paper in Development describes the molecular mechanism behind the temperature-dependent enhancement of grafting. We caught up with first authors Phanu Serivichyaswat and Kai Bartusch and corresponding author Charles Melnyk, Assistant Professor at Swedish University of Agricultural Sciences (SLU) in Uppsala, Sweden, to find out more about their research.

Near band edge and defect emissions in wurtzite Cd0.025Mg0.10Zn0.875O nanocrystals

We report on near band edge and local defects emissions in Cd0·025Mg0·10Zn0·875O (CdMgZnO) nanoparticles (NPs) as a function of temperature, where a strong temperature-dependent near-infrared emission around 1.7 eV (~730 nm) has been observed. The NPs were synthesized by a modified sol-gel method and were annealed at 750 °C after growing. The crystallographic parameters have been determined by 2-dimensional synchrotron x-ray diffraction (XRD) and conventional XRD analysis, confirming their growth within the wurtzite phase with a preferred orientation along the (101) plane and an apparent crystallite size of 52.72 ± 0.18 nm. This apparent crystallite size is consistent with the nearly hexagonal particle shape (50.15 ± 0.38 nm) obtained from high resolution transmission electron microscopy. Valence Electron Energy Loss Spectroscopy (VEELS) has been conducted to gain information on the band structure and interband transitions. From the VEELS spectrum, an onset bandgap of 3.2 ± 0.3 eV was attributed to Cd/Mg co-doped ZnO. The temperature-dependent photoluminescence properties and enhancement of the optically active local defects emission have been analyzed.

Measurement of temperature-dependent linewidth enhancement factor in a 1550 nm VCSEL

In this paper, we have investigated experimentally measured temperature-dependent Linewidth Enhancement Factor (α) of solitary 1550 nm InAlGaAs-InP multi-quantum-well vertical-cavity surface-emitting lasers (VCSELs). The temperature effects on (α) are investigated for a temperature range of −20°C to 60°C. Comparison is made between the experimental observations and theoretical predictions of similar VCSELs and with those different in wavelength or materials or in both.

The Temperature-Dependent Effectiveness of Platinum-Based Drugs Mitomycin-C and 5-FU during Hyperthermic Intraperitoneal Chemotherapy (HIPEC) in Colorectal Cancer Cell Lines.

Cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC) is a treatment with curative intent for peritoneal metastasis of colorectal cancer (CRC). Currently, there is no standardized HIPEC protocol: choice of drug, perfusate temperature, and duration of treatment vary per institute. We investigated the temperature-dependent effectiveness of drugs often used in HIPEC. Methods: The effect of temperature on drug uptake, DNA damage, apoptosis, cell cycle distribution, and cell growth were assessed using the temperature-dependent IC50 and Thermal Enhancement Ratio (TER) values of the chemotherapeutic drugs cisplatin, oxaliplatin, carboplatin, mitomycin-C (MMC), and 5-fluorouracil (5-FU) on 2D and 3D CRC cell cultures at clinically relevant hyperthermic conditions (38–43 °C/60 min). Results: Hyperthermia alone decreased cell viability and clonogenicity of all cell lines. Treatment with platinum-based drugs and MMC resulted in G2-arrest. Platinum-based drugs display a temperature-dependent synergy with heat, with increased drug uptake, DNA damage, and apoptosis at elevated temperatures. Apoptotic levels increased after treatment with MMC or 5-FU, without a synergy with heat. Conclusion: Our in vitro results demonstrate that a 60-min exposure of platinum-based drugs and MMC are effective in treating 2D and 3D CRC cell cultures, where platinum-based drugs require hyperthermia (>41 °C) to augment effectivity, suggesting that they are, in principle, suitable for HIPEC.

An RNA thermoswitch regulates daytime growth in Arabidopsis.

Temperature is a major environmental cue affecting plant growth and development. Plants often experience higher temperatures in the context of a 24 h day-night cycle, with temperatures peaking in the middle of the day. Here, we find that the transcript encoding the bHLH transcription factor PIF7 undergoes a direct increase in translation in response to warmer temperature. Diurnal expression of PIF7 transcript gates this response, allowing PIF7 protein to quickly accumulate in response to warm daytime temperature. Enhanced PIF7 protein levels directly activate the thermomorphogenesis pathway by inducing the transcription of key genes such as the auxin biosynthetic gene YUCCA8, and are necessary for thermomorphogenesis to occur under warm cycling daytime temperatures. The temperature-dependent translational enhancement of PIF7 messenger RNA is mediated by the formation of an RNA hairpin within its 5' untranslated region, which adopts an alternative conformation at higher temperature, leading to increased protein synthesis. We identified similar hairpin sequences that control translation in additional transcripts including WRKY22 and the key heat shock regulator HSFA2, suggesting that this is a conserved mechanism enabling plants to respond and adapt rapidly to high temperatures.

Anomalous enhancement of resurgent Na+ currents at high temperatures by SCN9A mutations underlies the episodic heat-enhanced pain in inherited erythromelalgia

Inherited erythromelalgia (IEM), caused by mutations in Nav1.7 channel is characterized by episodic neuropathic pain triggered especially by warm temperature. However, the mechanism underlying the temperature–dependent episodic attacks of IEM remains elusive. We investigated the electrophysiological effect of temperature changes on Nav1.7 channels with three different mutations, p.I136V, p. I848T, and p.V1316A, both in vitro and in vivo. In vitro biophysical studies of the mutant channels show consistent temperature-dependent enhancement of the relative resurgent currents if normalized to the transient currents, as well as temperature-dependent changes in the time to peak and the kinetics of decay of the resurgent currents, but no congruent temperature–dependent changes in steady–state parameters such as shift of activation/inactivation curves and changes of the absolute size of the window or resurgent currents. In vivo nerve excitability tests (NET) in IEM patients reveal the essentially normal indices of NET at a single stimulus. However, there are evident abnormalities if assessed with preconditioning pulses, such as the decrease of threshold elevation in hyperpolarizing threshold electrotonus (50–100 ms), the increase of inward rectification in current–voltage curve, and the increase of refractoriness at the interpulse interval of 2–6 ms in recovery cycle, probably also implicating derangements in temperature dependence of inactivation and of recovery from inactivation in the mutant channels. The pathogenesis of heat–enhanced pain in IEM could be attributed to deranged temperature dependence of Nav1.7 channels responsible for the genesis of resurgent currents.

Temperature-Dependent Enhancement Effects for TBD (1,5,7-Triazabicyclo[4.4.0]dec-5-ene) with 2-Methylimidazole-Intercalated α-Zirconium Phosphate as a Latent Thermal Initiator in the Reaction of Glycidyl Phenyl Ether

The catalytic effects of 1,1,3,3-Tetramethylguanidine (TMG), 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD), 7-Methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) in the reaction with glycidyl phenyl ether (GPE) at 40 °C were investigated. For the reaction, the %conversion of GPE was only 11%, carried out at 40 °C over 14 days in the presence of TBD.Additionally, there was little catalytic activity for the same reaction performed under typical storage conditions at 25 °C. The effect of TBD with 2-methylimidazole-intercalated α-zirconium phosphate (α-ZrP∙2MIm), as a latent thermal initiating system in the reaction with GPE, was then examined. The reaction did not proceed within 1 h at 80 °C. On increasing the temperature to 120 °C, the %conversion reached 75% for reaction at 1 h. Under typical storage conditions (7 days at 25 °C), the %conversion of GPE was only 7%. With addition of TBD to α-ZrP∙2MIm, reagent stability was maintained, and the polymerization reaction proceeded rapidly with the application of heat.

Resonance Raman Spectroscopy of Mn-Mgk Cation Complexes in GaN

Resonance Raman analysis is performed in order to gain insight into the nature of impurity-induced Raman features in GaN:(Mn,Mg) hosting Mn-Mgk cation complexes and representing a prospective strategic material for the realization of full-nitride photonic devices emitting in the infra-red. It is found that in contrast to the case of GaN:Mn, the resonance enhancement of Mn-induced modes at sub-band excitation in Mg co-doped samples is not observed at an excitation of 2.4 eV, but shifts to lower energies, an effect explained by a resonance process involving photoionization of a hole from the donor level of Mn to the valence band of GaN. Selective excitation within the resonance Raman conditions allows the structure of the main Mn-induced phonon band at ~670 cm−1 to be resolved into two distinct components, whose relative intensity varies with the Mg/Mn ratio and correlates with the concentration of different Mn-Mgk cation complexes. Moreover, from the relative intensity of the 2LO and 1LO Raman resonances at inter-band excitation energy, the Huang-Rhys parameter has been estimated and, consequently, the strength of the electron-phonon interaction, which is found to increase linearly with the Mg/Mn ratio. Selective temperature-dependent enhancement of the high-order multiphonon peaks is due to variation in resonance conditions of exciton-mediated outgoing resonance Raman scattering by detuning the band gap.

Intermittency enhancement in quantum turbulence in superfluidHe4

Intermittency is a hallmark of turbulence, which exists not only in turbulent flows of classical viscous fluids but also in flows of quantum fluids such as superfluid $^4$He. Despite the established similarity between turbulence in classical fluids and quasi-classical turbulence in superfluid $^4$He, it has been predicted that intermittency in superfluid $^4$He is temperature dependent and enhanced for certain temperatures, which strikingly contrasts the nearly flow-independent intermittency in classical turbulence. Experimental verification of this theoretical prediction is challenging since it requires well-controlled generation of quantum turbulence in $^4$He and flow measurement tools with high spatial and temporal resolution. Here, we report an experimental study of quantum turbulence generated by towing a grid through a stationary sample of superfluid $^4$He. The decaying turbulent quantum flow is probed by combining a recently developed He$^*_2$ molecular tracer-line tagging velocimetry technique and a traditional second sound attenuation method. We observe quasi-classical decays of turbulent kinetic energy in the normal fluid and of vortex line density in the superfluid component. For several time instants during the decay, we calculate the transverse velocity structure functions. Their scaling exponents, deduced using the extended self-similarity hypothesis, display non-monotonic temperature-dependent intermittency enhancement, in excellent agreement with recent theoretical/numerical study of Biferale et al. [Phys. Rev. Fluids 3, 024605 (2018)].