External Cold Research Articles

External cold and vibration with BUZZY versus topical anesthetic gel for pain and anxiety associated with infiltrative anesthesia in pediatric dentistry: a double-blinded, split-mouth, randomized, controlled trial

External cold and vibration with BUZZY versus topical anesthetic gel for pain and anxiety associated with infiltrative anesthesia in pediatric dentistry: a double-blinded, split-mouth, randomized, controlled trial

Investigating the synergy of blockage ratio and external cold heat exchanger in standing-wave thermoacoustic engines: An experimental study

Thermoacoustic engines (TAE) offer a promising avenue for converting low-grade heat into useable energy. Despite its simplicity in fabrication, designing thermoacoustic engines face efficiency challenges hindering their widespread adoption. One key obstacle faced by current thermoacoustic devices is their lack of efficiency. The core components of TAE are the stack, Cold Heat Exchanger (CHX), Hot Heat Exchanger (CHX) and the resonator. These components are crucial in advancing the performance of thermoacoustic engines. The CHX keeps the working gas cool, which is essential for the engine to function efficiently and create the desired acoustic wave. However, many existing efforts in this field have not taken into consideration the effect of the CHX design which may have effect on the operating temperature and the engines performance. This study examines the influence of different CHX blockage ratios (28 %, 36 %, 42 %, 47 %, and 59 %), along with the addition of an external CHX, on performance metrics. Measurements were conducted using air at room temperature and atmospheric pressure to assess temperature difference, startup time, volumetric velocity, and sound pressure levels. Key findings indicate that Efficiency directly correlates with volumetric velocity and inversely with onset temperature. Even though decreasing the blockage ratio increases operating temperature, it lengthens startup and reduces volumetric velocity, suggesting increased axial conduction. In addition, External CHX lowers operating temperature, reducing volumetric velocity and sound pressure. Interestingly, resonance frequency remains unaffected by CHX blockage ratio changes. An optimal configuration with a 42–47 % blockage ratio achieves 5.92 m/s velocity, 136 s startup time, and 77 °C onset temperature. These findings offer valuable insights for optimizing thermoacoustic engine efficiency and advancing their potential as sustainable energy solutions.

Novel liquid air energy storage coupled with liquefied ethylene cold energy: Thermodynamic, exergy and economic analysis

Liquid air energy storage (LAES) technology, unrestricted by geographical conditions and capable of flexible integration with external energy sources, holds considerable potential. However, the efficiency of the LAES system is hindered by the shortage of cold energy, requiring the introduction of external cold energy. Currently, research on external cold energy coupling predominantly concentrates on the regasification cold energy of Liquefied Natural Gas (LNG), with scant attention to other cold energy sources, such as ethylene. The conventional regasification process of Liquefied Ethylene (LE) is accompanied by the wasting of abundant regasification cold energy, making it crucial to explore a method to effectively recover and utilize it. This study firstly presents two system cases that couple LAES with the regasification cold energy of LE, filling the research gap. Two cases are simulated: Case 1 utilizes the LE cold energy to cool the air after compression, similar to the common method of coupling LNG cold energy, and Case 2 innovatively applies LE cold energy in low-temperature compression and cooling after compression, along with the introduction of 350 ℃ solar thermal energy. Key parameters in Case 2 are optimized through sensitivity analysis. Additionally, exergy destruction and economic analysis of the two cases are conducted. The main results indicate that: the round-trip efficiency (RTE) and exergy efficiency (EXE) of Case 1 are 63.3% and 59.5%, respectively; for Case 2, although the EXE of 57.06% is slightly lower than Case 1, the RTE can be markedly improved to 211.4%, and it has a lower initial investment cost, quicker return, and lower investment risk. This study systematically presents a novel technical solution for the integration of external cold energy with LAES systems, marking the first investigation into the coupling of LAES systems with liquefied ethylene regasification processes.

The future of artificial hibernation medicine: protection of nerves and organs after spinal cord injury.

Spinal cord injury is a serious disease of the central nervous system involving irreversible nerve injury and various organ system injuries. At present, no effective clinical treatment exists. As one of the artificial hibernation techniques, mild hypothermia has preliminarily confirmed its clinical effect on spinal cord injury. However, its technical defects and barriers, along with serious clinical side effects, restrict its clinical application for spinal cord injury. Artificial hibernation is a future-oriented disruptive technology for human life support. It involves endogenous hibernation inducers and hibernation-related central neuromodulation that activate particular neurons, reduce the central constant temperature setting point, disrupt the normal constant body temperature, make the body "adapt" to the external cold environment, and reduce the physiological resistance to cold stimulation. Thus, studying the artificial hibernation mechanism may help develop new treatment strategies more suitable for clinical use than the cooling method of mild hypothermia technology. This review introduces artificial hibernation technologies, including mild hypothermia technology, hibernation inducers, and hibernation-related central neuromodulation technology. It summarizes the relevant research on hypothermia and hibernation for organ and nerve protection. These studies show that artificial hibernation technologies have therapeutic significance on nerve injury after spinal cord injury through inflammatory inhibition, immunosuppression, oxidative defense, and possible central protection. It also promotes the repair and protection of respiratory and digestive, cardiovascular, locomotor, urinary, and endocrine systems. This review provides new insights for the clinical treatment of nerve and multiple organ protection after spinal cord injury thanks to artificial hibernation. At present, artificial hibernation technology is not mature, and research faces various challenges. Nevertheless, the effort is worthwhile for the future development of medicine.

Effectiveness of External Cold and Vibration Stimulation Via Buzzy on Pain During Venipuncture Among Children In A Selected Hospital, Bangalore

Effectiveness of External Cold and Vibration Stimulation Via Buzzy on Pain During Venipuncture Among Children In A Selected Hospital, Bangalore

Exploring the synergistic pharmacological mechanism of Huoxiang Drink against irritable bowel syndrome by integrated data mining and network pharmacology.

Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder, characterized by abdominal pain, bloating, and changes in bowel habits. Huoxiang Drink (HD), derived from traditional Chinese medicine, has been reported to effectively treat digestive disorders caused by external cold and internal dampness. However, the pharmaceutical targets and mechanisms for HD against IBS remain unclear. Data mining, bioinformatics analysis, and network pharmacology were employed to explore the potential pharmacological mechanisms of HD against IBS. In this study, we screened 50 core targets to investigate the pharmacological mechanisms of HD against IBS. Enrichment analysis revealed that HD may participate in various signaling pathways, especially the inflammation-related tumor necrosis factor, signaling pathway and hypoxia-inducible factor signaling pathway. Molecular docking results confirmed that MOL000098 (Quercetin), MOL000006 (Luteolin), MOL005828 (Nobiletin), MOL005916 (Irisolidone), and MOL004328 (Naringenin), as key active ingredients in HD, bound to core targets (tumor protein P53, tumor necrosis factor, matrix metalloproteinases 9, and vascular endothelial growth factor-A) for topical treatment of IBS. This study suggested that HD offered a potential therapeutic strategy against IBS. Our findings may facilitate the efficient screening of active ingredients in HD and provide a theoretical basis for further validating the clinical therapeutic effects of HD on treating IBS.

External cold atmospheric plasma-responsive on-site hydrogel for remodeling tumor immune microenvironment

Although immunotherapy has recently emerged as a promising anti-tumor approach, it remains limited by the immunosuppressive tumor microenvironment. Cold atmospheric plasma irradiation can generate reactive oxygen species and trigger the presentation of tumor-associated antigens. Here, we exploited cold atmospheric plasma for on-site hydrogel application in the tumor environment, aiming to facilitate the sustainable uptake of tumor-associated antigens and nanoadjuvants by dendritic cells. Hyaluronic acid-tyramine conjugate was intratumorally injected as a liquid and formed an on-site hydrogel under irradiation with cold atmospheric plasma. Intratumoral delivery of hyaluronic acid-tyramine conjugate with transforming growth factor β-blocking nanoadjuvant (TLN) followed by cold atmospheric plasma irradiation yielded a micro-network of TLN-loaded hydrogel (TLN@CHG). In vivo intratumoral injection of TLN@CHG promoted the activation of dendritic cells and more effectively increased the proportion of CD4 T cells and CD8 T cells in the tumor microenvironment, compared to the groups receiving TLN or hydrogel alone. Moreover, in CT26 tumor model mice, cold atmospheric plasma-induced TLN@CHG therapy ablated the primary tumor and provided 100% survival among mice rechallenged with CT26 cells. Taken together, our findings suggest that an on-site hydrogel-based micro-network of TLN has the potential to remodel the tumor immune microenvironment. Although we used TLN in this study, the concept could be extended to support the sustained action of other nanoadjuvants in a hydrogel micro-network.

Experimental investigations of flow and thermal behavior of wall confluent jets as a heating device for large-space enclosures

The study aimed to explore the effects of inlet air temperature, outdoor air temperature, inlet bulk velocity, and the number of nozzles on wall confluent jets (WCJ) propagating along an external cold wall in a large space enclosure such as a greenhouse. A combination of experimental study and Response surface methodology has been used to predict the flow and thermal behavior of the WCJ for the studied cases. Box-Behnken design was used to determine the case matrix for four of the above-mentioned vital variables for non-isothermal cases. The experimental study employed constant current anemometers to measure the velocity and temperature of the WCJ. Results showed that the WCJ attached to the wall under both isothermal and non-isothermal conditions. This flow behavior suggests that the WCJ can be used to heat the external facades of large-space enclosures. All the stated variables were critical to the decay factor and decay rate of maximum velocity, albeit at varying levels. The velocity decayed faster with an increase in the inlet bulk velocity and outdoor air temperature. It also decayed faster as the number of nozzles and inlet air temperature decreased. The external wall surface temperature and the wall-heating effect increased as the momentum of the jet increased. The surface temperature on the external wall was most influenced by the inlet air temperature and least by the number of nozzles. Correlations of the second-order polynomial for the Response surface models that estimate the rate of velocity decay and temperature on the external wall were obtained.

Lightweight shear stiffening gel with enhanced mechanical and thermal-insulating performance for advanced fire suit

A lightweight and thermal-insulating shear stiffening gel (LT-SSG) with anti-impact was developed via introducing hollow glass microspheres BR20 into shear stiffening gel (SSG). It was lightweight enough to be placed on a leaf. LT-SSG showed the ability to resist impact. Finally, a multifunctional Kevlar safeguarding suit (MKSS) with flame retardant property was fabricated. It exhibited good adiabatic effect which could isolate heat at high temperatures and prevent heat loss at low temperatures. • LT-SSG with lightweight, heat-insulation and anti-impact properties was prepared. • LT-SSG showed enhanced protective effect due to the existence of BR20 particles. • A multifunctional Kevlar safeguarding suit (MKSS) was assembled. • MKSS was capable to resist fire combustion and displayed good adiabatic effect. • MKSS effectively prevented the heat loss from humans in cold environment. Herein, a lightweight and thermal-insulating shear stiffening gel (LT-SSG) with anti-impact was prepared by introducing insulating glass microspheres BR20 into SSG. The density of LT-SSG was 48.97% lower than that of SSG. Meantime, LT-SSG showed excellent energy absorption effect. The remained impact force of LT-SSG was only 0.23 kN compared with 0.41 kN of SSG when impacted from 20 cm. Moreover, LT-SSG with good thermal insulation performance could effectively isolate surrounding temperature to 42.6 ℃ at 80 ℃ and block external cold temperature to protect the heat loss from human body. While SSG as well as the breakage of BR20 particles absorbed and dissipated much impact energy, proving its excellent protective properties. Finally, a multifunctional Kevlar safeguarding suit (MKSS) was developed. It showed the ability to resist low-speed drop hammer and high-speed ballistic impact. To this end, the reported LT-SSG showed promising application in fire suit and body armors.

Cold Stress Response Mechanisms in Anther Development.

Unlike animals that can escape threats, plants must endure and adapt to biotic and abiotic stresses in their surroundings. One such condition, cold stress, impairs the normal growth and development of plants, in which most phases of reproductive development are particularly susceptible to external low temperature. Exposed to uncomfortably low temperature at the reproductive stage, meiosis, tapetal programmed cell death (PCD), pollen viability, and fertilization are disrupted, resulting in plant sterility. Of them, cold-induced tapetal dysfunction is the main cause of pollen sterility by blocking nutrition supplements for microspore development and altering their timely PCD. Further evidence has indicated that the homeostatic imbalances of hormones, including abscisic acid (ABA) and gibberellic acid (GA), and sugars have occurred in the cold-treated anthers. Among them, cold stress gives rise to the accumulation of ABA and the decrease of active GA in anthers to affect tapetal development and represses the transport of sugar to microspores. Therefore, plants have evolved lots of mechanisms to alleviate the damage of external cold stress to reproductive development by mainly regulating phytohormone levels and sugar metabolism. Herein, we discuss the physiological and metabolic effects of low temperature on male reproductive development and the underlying mechanisms from the perspective of molecular biology. A deep understanding of cold stress response mechanisms in anther development will provide noteworthy references for cold-tolerant crop breeding and crop production under cold stress.

The effects of virtual reality glasses and external cold and vibration on procedural pain and anxiety in children during venous phlebotomy: randomized controlled trial

The effects of virtual reality glasses and external cold and vibration on procedural pain and anxiety in children during venous phlebotomy: randomized controlled trial

Sini Decoction inhibits TLR4/NF-κB signaling pathway to improve airway remodeling of allergic asthmatic mice

This study aims to explore the effect of Sini Decoction on Toll-like receptor 4(TLR4)/nuclear factor-κB(NF-κB) signaling pathway in the mice with allergic asthma(AA). Forty-eight SPF-grade BALB/c mice were randomly assigned into a blank control group, a model group, a dexamethasone group, and high-, medium-, and low-dose Sini Decoction groups, with 8 mice in each group. The sensitization solution made of ovalbumin and aluminum hydroxide powder was injected intraperitoneally in other groups except the blank control group which was injected with an equal volume of normal saline. The solution(or normal saline) was injected three times in total with an interval of 7 days. At the same time of sensitization, external cold stimulation and ice water were administered in a 4 ℃ climate box for 20 min every day. After modeling, the mice in each group were administrated with corresponding drugs by gavage for 3 weeks. At the end of administration, pentobarbital sodium(30 mg·kg~(-1)) was used for anesthesia, and then the samples were collected for the determination of various indexes. The phenol red test was conducted to evaluate tracheal excretion function. The histopathological changes of lung tissue were observed via hematoxylin-eosin(HE) staining. Masson staining was employed to reveal the deposition of blue collagen fibers around bronchi in lung tissue and the area occupied by blue collagen fibers was calculated. Immunofluorescence method was used to measure the expression of bronchial type Ⅰ collagen(Col-Ⅰ) and α-smooth muscle actin(α-SMA). The protein and mRNA levels of TLR4, NF-κB, cysteinyl aspartate specific proteinase-1(caspase-1), and interleukin-13(IL-13) were determined by Western blot and real-time fluorescence quantitative polymerase chain reaction(real-time PCR), respectively. Compared with the model group, Sini Decoction significantly increased the phenol red excretion from trachea, lowered the lung inflammation score, reduced subepithelial collagen deposition, and decreased Col-Ⅰ and α-SMA levels. Furthermore, the decoction down-regulated the protein and mRNA levels of TLR4, NF-κB, caspase-1, and IL-13 in mouse lung tissue. In conclusion, Sini Decoction can improve air remodeling by inhibiting the TLR4/NF-κB signaling pathway.

Microstructural evolution of external cold extrusion spinning 304 stainless steel with cumulative large deformation in multiple passes

Microstructural evolution of external cold extrusion spinning 304 stainless steel with cumulative large deformation in multiple passes

Multiple gas acquisition events in galaxies with dual misaligned gas disks

Frequent accretion of external cold gas is thought to play an important role in galaxy assembly. However, almost all known kinematically misaligned galaxies identify only one gas disk that is misaligned with the stellar disk, implying a single gas acquisition event. Here we report a new configuration in two galaxies where both contain two gas disks misaligned with each other and also with the stellar disk. Such systems are not expected to be stable or long-lasting, challenging the traditional picture of gas accretion of galaxies and their angular momentum build-up. The differences in kinematic position angles are larger than 120{\deg} between the two gas disks, and 40{\deg} between each gas disk and the stellar component. The star formation activity is enhanced at the interface of the two gas disks compared with the other regions within the same galaxy. Such systems illustrate that low-redshift galaxies can still experience multiple gas acquisition events, and provide a new view into the origins of galactic gas.

The Effect of External Cold and Vibration on Infiltration-Induced Pain in Children: A Randomized Clinical Trial.

Introduction Children's fear of and anxiety about dental treatments are important problems in maintaining health. The anesthetic injection is the main cause of dental fear. One of the methods to reduce the infiltration-induced pain is to use external cold or vibration using the gate control system. Various devices have been used to apply cold and vibration, including the BUZZY device (BUZZY Company, Arizona). Studies have shown contradictory results for the effectiveness of cold and vibration. This study aimed to investigate the effect of cold and vibration versus cold alone on maxillary infiltration-induced pain and stress. Methods Thirty children aged 6–12 years who required profound restoration of deciduous or permanent first molars were recruited in this randomized double-blind clinical trial. The anesthetic gel and BUZZY device were used in half of the children's jaws, and the anesthetic gel and the cold alone were used in the other half of the jaws. To measure stress from the heart rate, the Wong–Baker scale was used as the subjective scale, and the face, legs, activity, cry, consolability (FLACC) scale was used as the objective scale. Results The FLACC score was significantly lower in the BUZZY group than in the cold-alone group, but the Wong–Baker scale and heart rate did not show a significant difference between the two groups. Conclusions The BUZZY device can be effective in reducing infiltration-induced dental pain.

Topical Analgesic Containing Methyl Salicylate and L-Menthol Accelerates Heat Loss During Skin Cooling for Exercise-Induced Hyperthermia

Hyperthermia impairs physical performance and, when prolonged, results in heat stroke or other illnesses. While extensive research has investigated the effectiveness of various cooling strategies, including cold water immersion and ice-suit, there has been little work focused on overcoming the cutaneous vasoconstriction response to external cold stimulation, which can reduce the effectiveness of these treatments. Over-the-counter (OTC) topical analgesics have been utilized for the treatment of muscle pain for decades; however, to date no research has examined the possibility of taking advantage of their vasodilatory functions in the context of skin cooling. We tested whether an OTC analgesic cream containing 20% methyl salicylate and 6% L-menthol, known cutaneous vasodilators, applied to the skin during skin cooling accelerates heat loss in exercise-induced hyperthermia. Firstly, we found that cutaneous application of OTC topical analgesic cream can attenuate cold-induced vasoconstriction and enhance heat loss during local skin cooling. We also revealed that core body heat loss, as measured by an ingestible telemetry sensor, could be accelerated by cutaneous application of analgesic cream during ice-suit cooling in exercise-induced hyperthermia. A blunted blood pressure response was observed during cooling with the analgesic cream application. Given the safety profile and affordability of topical cutaneous analgesics containing vasodilatory agents, our results suggest that they can be an effective and practical tool for enhancing the cooling effects of skin cooling for hyperthermia.

Optimal thermal management of server cooling system based cooling tower under different ambient temperatures

• A new model is introduced to analyze year-round cooling system power consumption. • Optimal water operation conditions under different ambient temperatures are given. • Year-round energy consumption analysis is done by taking Tianjin as a study case. • Significant year-round cooling power can be saved by optimizing thermal parameters. To develop a highly efficient and energy-saving cooling system in a data center, this study investigates the optimal thermal management both on the internal server cooling cycle and external cold source water cycle under different ambient temperatures based on the principle of minimal power consumption. Taking a server cabinet of 4.8 kW as the case, an internal indirect water-cooled heat sink cycle and an external cooling tower cold source cycle are constructed. A hybrid thermal management model combined with a heat dissipation model and a power consumption model was developed with the aid of MATLAB and TRNSYS. Using this model, the relationship between the chip dissipation performance attached to the fin-type heat sink and the energy consumption performance of the cooling system under different water working conditions and ambient temperatures was analyzed. Finally, to achieve minimal system energy consumption, the optimized inlet temperature and water flow rates corresponding to different ambient temperatures were obtained by fitting expressions that can better serve the optimal design of data center cooling systems. Furthermore, when the optimal value was applied using the year-round temperature of Tianjin, China in the case study, a 21.3% reduction in power consumption and a 4.43% decrease in the power usage effectiveness can be achieved compared to the case without optimization. Therefore, significant power can be saved in a data center cooling system through thermal management optimization.

Temperature Load Mode of Bridge in Permafrost Region of Qinghai–Tibet Railway

The Qinghai–Tibet railway is the plateau permafrost railway with the highest altitude and the longest line in the world. The natural conditions along the line are harsh, with many unfavorable factors such as low temperature, strong ultraviolet radiation, and large changes in daily temperature, resulting in frequent bridge damage. In order to study the bridge temperature field and its effect in the permafrost region of the Qinghai–Tibet railway, a long-term field test was carried out, and a calculation model of sunshine temperature field of concrete two-piece T-beam was established based on the principle of meteorology and heat transfer. On this basis, the beam temperature difference load mode, beam section temperature distribution law, and temperature effect were obtained. As revealed, the daily temperature difference of the Qinghai–Tibet railway bridge is large in winter, which is related to the ground’s effective radiation and surface reflectivity, and the maximum value has exceeded the current codes. The beam section temperature field shows “internal heat and external cold” in the morning and “internal cold and external heat” from noon to evening. Under the action of strong radiation and large temperature difference, bridge displacement occurs frequently, by which it is easy to cause damage to rail fasteners and bridge bearings. Based on the field test and finite element analysis, the bridge temperature difference load mode was proposed, which makes up for the deficiency that the relevant codes do not consider the plateau’s special climatic conditions and can provide a reference for the construction of plateau railways such as the Sichuan–Tibet railway.

Heat distribution and the condition of hypothermia in the multi-layered human head: A mathematical model

The conduction, perfusion and metabolic heat generation based partial differential equation has been used to study the heat transfer in human head. The main objective of this study is to predict the temperature distribution at the multi-layered human head that results in hypothermic condition. The temperature profiles have been estimated at the interface points of brain, skull and scalp with respect to various parameters including atmospheric temperature, arterial temperature and metabolic heat generation. The variational finite element method and analytical method based on Laplace transform has been employed to establish the solution of the formulated model, and the resulting outcomes are illustrated graphically. Under cold exposure, the blood capillaries around scalp exchange core heat with the external cold environment and experience lowering in the tissue temperature of the blood in the scalp. It is reflected in the graphical view of the model that the prolonged exposure to cold transmits its effect into the deep brain capillaries, wherein the temperature gradually lowers down below the normal body temperature that results hypothermia and hence abnormal body homoeostasis.

Effectiveness of using external cold and vibration on level of pain among children

Introduction: Pain is one of the most misunderstood, under-diagnosed, and under-treated/untreated medical problems, particularly in children. One of the most challenging roles of medical providers serving children is to appropriately assess and treat pain. Objective: To assess the effectiveness of external cold and vibration on level of pain during intravenous cannulation among hospitalized children.Study Design: A quasi-experimental research design was used. Participants: Total 60 children in the age group of 4-12 years. Intervention: External cold and vibration via “buzzy” one minute before, during and till one minute after the procedure.Outcome: Level of pain measured with standardized FLACC behavioral assessment scale Results: both the groups were homogenous in terms of socio demographic variables such as age, gender, religion, birth order, informer and socioeconomic status of parents with p>0.05. The mean pain score during IV cannulation in experimental group was lower (1.37±1.829) than control group (1.50±1.480) and this difference was statistically non-significant (p >0.05). One minutes after IV cannulation procedure, the mean pain score in experimental group was 0.00±0.00 while in control group was 0.07±0.254 (p>0.05).Conclusion: The study findings revealed that external cold and vibration does not reduces the level of intravenous cannulation procedural pain significantly in children.