Rapid Immersion Research Articles

A rapid immersion measurement for the diffusion constant of chloride ions in the geopolymer concrete

Accurate measurement of chloride ion diffusion coefficient, without external interference, is essential for obtaining data that closely reflects practical conditions. The diffusion constants of chloride ions within fly ash-based geopolymer concrete (FGPC) with a one-dimension immersion method employed to record the time taken for diffusion to occur over a specific distance were investigated in this work. The results showed a clear relationship between the diffusion constant and the strength of FGPC. Within the same strength of FGPC, the diffusion distance (thickness) is proportional to the square root of diffusion time. The minimum diffusion constant is approximately 8.90 × 10−11 m2/s which is close to the result in an immersion test. The method employed in this study is demonstrated to be both feasible and applicable for assessing the diffusion constant of chloride ions in FGPC quickly. It promotes a rapid evaluation method to predict the diffusion process under practical conditions.

Advancing drinking water safety: Facile fabrication of nanofiltration membrane for enhanced antibiotics removal and efficient water softening

Long-term water consumption with contaminated antibiotics and high levels of hardness threatens the health of humans and animals. In this study, a novel positively charged nanofiltration membrane was designed for the dual purpose of efficiently removing antibiotics and softening hard water. The membrane was fabricated by casting P84 polymer solution onto non-woven fabrics, followed by immersion in the polyethyleneimine (PEI) solution for phase inversion and cross-linking, and finalized interfacial polymerization with trimesoyl chloride. Notably, the rapid immersion of the P84 substrate into PEI drastically reduces preparation time by 95 % compared to the regular method while maximizing PEI storage, resulting in uniform pore sizes and a positively charged surface. The optimal membrane showed a high water permeance of 11.3 L m−2 h−1 bar−1 and exceptional antibiotic rejection, i.e., 99.6 % for enrofloxacin, 99.2 % for ciprofloxacin, and 96.3 % for sulfamethoxazole, as well as a highly effective removal in water hardness (over 96 % of Ca2+ and Mg2+) at 4 bar. Simulated water separation tests showed that the optimal membrane effectively controls hard water salinity within optimum drinking water ranges (Ca2+ ≤ 80 mg/L; Mg2+ ≤ 30 mg/L), providing efficient water softening and antibiotic capture ability. Additionally, the optimal membrane demonstrated a superior anti-bacterial and long-term stability performance. This study has significant potential for improving drinking water supply safety and addressing pressing public health and environmental concerns.

A simple, rapid and entertaining method to measure specific heat of metals using liquid nitrogen and Leidenfrost effect

Taking advantage of the fascination of ‘playing’ with liquid nitrogen, this article proposes a didactical experiment involving the use of this liquid to measure the heat capacity of cylindrical metallic blocks (copper, aluminum, brass, and stainless steel; volume ≈ 20 cm3). It also permits to demonstrate qualitatively and quantitatively the Leidenfrost effect. The experimental setup consists of a low-cost recipient adequate for liquid N2 storage, a multimeter and a weighing scale. The experience starts by a rapid immersion of metallic block in liquid N2 and by measuring simultaneously the block’s temperature and the mass of the evaporated liquid along the cooling process. Knowing the latent heat of the liquid L , the evaporated mass Δm during a temperature variation ΔT , the heat capacity is obtained by Cp=L Δm/ΔT . This method allowed to measure the specific heat in the 100–270 K temperature range in less than 3 min and the results are in quite good agreement with the literature data. On the other hand, the cooling rate, measured by temperature and liquid N2 change, clearly shows two regimes as expected by the Leidenfrost effect and the critical heat flux calculated is in good agreement with previous experiments. Such an experiment can be adapted to various student levels and present a didactical approach to important thermodynamical concepts in parallel with appealing phenomena.

The effect of staged versus rapid immersion on the cardio-respiratory components of the cold-shock response

Drowning is one of the leading causes of accidental death. Sudden cold-water immersion (CWI) leads to the stimulation of cutaneous cold receptors causing the cold-shock response (CSR) which includes a gasp, hyperventilation, and tachycardia for several minutes. Only one study has investigated staged CWI (Hayward and French, 1989, Av Space Env Med, 60, 1163-1165) and found a reduction in minute ventilation (V̇E) and respiratory frequency (fB) occurred when immersed to the waist for 30 s followed by to the shoulders. However, it is unclear whether a staged entry with a longer or shorter period at the waist would elicit a greater or lesser CSR. Thus, the aim of this study is to establish whether a staged immersion with a longer period immersed to the waist would attenuate the initial cardio-respiratory responses associated with CWI, when compared with rapid immersion. Ethical approval was gained from the University of Portsmouth Science Faculty Research Ethics Committee (SHFEC 2020-070). Seven male participants completed two, 5 min immersions that occurred at the same time of day (± 2 h) to avoid circadian variation in internal body temperature: a staged immersion (immersion to the iliac crest for 2 min prior to immersion to the acromion process); a rapid immersion (immersion to the acromion process for 5 min). Participants were lowered into stirred water (15°C) at a rate of 4 s to the waist, 4 s to the shoulder. Inspiratory and expiratory data were collected using a ventilatory turbine module and Douglas bags, respectively, whilst heart rate data was collected using a three-lead ECG. Variables were analysed over the first 30 s of immersion by a one-way ANOVA and a Tukey post hoc test. Effect sizes were calculated using Cohen’s d. Staged immersion to the waist resulted in a significantly lower fB (P < 0.05; d = 1.54) and V ̇E (P < 0.01; d = 1.96) over the first 30 s epoch, when compared to rapid immersion. Staged immersion to the shoulders resulted in a lower ventilatory equivalent of oxygen (P < 0.005; d = 1.95). There was no difference in heart rate between immersions. A staged immersion to the waist resulted in a 36.2% lower V̇E and 29.4% lower fB, potentially due to fewer cutaneous cold receptors being stimulated. This reduces the potential to aspirate water due to a lower ventilatory drive, therefore, could reduce drowning incidence attributed to the CSR.

SCREENING FOR A SUITABLE CRYOPRESERVATION PROTOCOL FOR Polypodium vulgare

Cryopreservation (storage at -196°C) is one of the techniques used for ex situ conservation to guarantee the long-term storage of different biological materials. Polypodium vulgare (Common polypody) is an evergreen fern used as food and medicine. To our knowledge, no cryopreservation protocol for gametophytes from this species is available. In this context, our paper aimed to screen a suitable cryopreservation protocol for P. vulgare - an important source of secondary metabolites. Different protocols were tested to identify a suitable cryopreservation protocol. Techniques like light microscopy and biochemical assays were used to certify an appropriate protocol for this fern. Gametophyte desiccation for 3 hours in the sterilized airflow before rapid immersion in liquid nitrogen provides sufficient dehydration to assure a good rate of survival.

로맨스 웹소설 속 가상 역사의 구현 방식 연구

This paper discussed the realization of virtual history in romance web novels, focusing on <Midnight Mirage>. <Midnight Mirage> depicted the love story with King Munjong and Queen Hyeondeok as motifs. <Midnight Mirage> used the story of Tumun-dong 72 Loyalists and the achievements of various national institutions in King Sejong to create various central event. The fictional elements of the story were used to form a inter-class romance, emphasize the personal feelings of the opposing forces and highlight the power of the crown prince. The characteristics of a virtual history are as follows. First, it was actively borrowing modern cultural customs. Second, it takes the form of a short episode when a historical figure appears. These characteristics have epic effects such as inducing rapid immersion of readers and relaxing the tension of the narrative.

The importance of the teacher’s role in the formation of a multicultural humanitarian and technical elite of the globalized worl

The article is aimed at studying the role of the teacher at the initial stage of teaching international students as a subject of the educational process and analysis of modern requirements for teachers, which forms a new generation of ethical technicians.
 In today’s world, education is a necessary factor in human progress, socio-economic development and global competitiveness. Higher education institutions teach students who will soon be able to operate independently in today’s economy. The development of the Ukrainian economy depends on the quality of training. The quality education and upbringing of a responsible, ethically literate personality of a specialist depends on the teacher, who is the central figure in the educational process.
 A multicultural audience deals with students’ diverse backgrounds in terms of mother tongue, ethnicity and culture. In the process of teaching and learning, diversity is taken into account when deciding on appropriate educational strategies. The National Technical University "Kharkiv Polytechnic Institute" conducted a set of applied research in the field of training of foreign citizens.
 Observational data are analyzed descriptively using innovative teaching methods of international students, and it can be concluded that the study will contribute to the formation of spiritually rich, highly educated professionals in various technical fields. Moreover, the results of this study show that teachers still play a significant role in the multicultural classroom.
 Therefore, teachers of foreign language training faculties should have knowledge of the peculiarities of students’ national culture, mentality and etiquette, religious traditions. It will help mitigate the rapid immersion of foreigners in the socio-cultural and linguistic environment of Ukraine. At the same time, among the professional qualities of a modern teacher, the innovative type of thinking, the ability to see and predict probable prospects for the development of applied technologies, as well as active independent research activities are of particular importance.

Illusions of online readiness: the counter-intuitive impact of rapid immersion in digital learning due to COVID-19

ABSTRACT Framed from a socio-cognitive perspective, and the contemporary increased salience of digital learning readiness and competence, the purpose of this study was two-fold: to validate Online Learner Readiness Scale in a new context and to explore potential variances in online readiness within a student-teacher population between less (pre-COVID) and more experienced (during COVID) groups. A CFA was used to examine the suitability of the OLRS in an Irish context, and variances between groups based on gender and professional experience were explored. Two cross-sectional datasets were gathered from student teachers from a university teacher education programme in the Republic of Ireland (n 1 = 281, n 2 = 154). The analysis demonstrated significantly lower perceived online readiness in the more experienced ‘during COVID’ cohort compared to ‘pre-COVID’ cohort. This counter-intuitive finding is in direct contrast to prior research, and potential influencing factors include the sudden immersion in an entirely digital learning environment. The more experienced cohort reported significantly lower online readiness across all five components of the OLRS. The findings are discussed in the context of a major shift in the student-teacher learning experience due to COVID-19. Implications for future research are explored in the context of increasingly digitised teaching and learning environments during and after the COVID-19 pandemic.

Podocarpo, a plant of ornamental interest: asexual propagation

The objective of this study was to evaluate the potential of rooting of podocarpos cuttings in function of the number of leaves, concentrations of IBA and phytorregulators, application methods and cutting season. Two experiments were carried out under weaning conditions, in a factorial scheme containing 3 replicates of 15 cuttings, the first with 4 concentrations of IBA, 3 leaves at the cuttings and 2 seasons. These were removed in August/2016 and January/2017, prepared with 10 cm in length and immersed in solutions for 10 s. In the second experiment three types of phytoregulators and 2 application forms were tested (slow and quick immersion). Cuttings were prepared in the same manner as in the first experiment, maintaining 4 leaves. The bases of the cuttings were immersed for 10 s and 24 h in the solutions, then taken to root. After 100 days of experimentation, it was concluded that cuttings collected in the summer had a higher percentage of rooting, 4 leaves and IBA concentration should be maintained between 750 and 800 mg L-1. The best form of application of phytoregulator is by rapid immersion.

Addition of disaccharides and dimethyl sulfoxide to sodium alginate gel improves viability of immobilized Saccharomyces boulardii after cryopreservation

Gel-immobilized microorganisms are increasingly used in microbiological industries. Currently, the problem of developing technologies for long-term storage of microorganisms immobilized in gel carriers remains urgent. Low-temperature storage is the most effective method of preserving microorganisms. The viability of immobilized cells is affected by cryoprotective properties of gel matrix as well as cooling regimes. Therefore, the effects of incorporation of cryoprotective agents in alginate gel and cooling regimes on the viability of immobilized Saccharomyces boulardii cells after cryopreservation were studied. Incorporation of non-permeable cryoprotectants (sucrose, lactose, and trehalose) and permeable one dimethyl sulfoxide (DMSO) in alginate gel beads promoted an increase in the viability of immobilized cells after freeze-thawing. The highest viability rates of the gel-immobilized cells were observed in the alginate gel beads incorporating combinations of DMSO (5 – 10 % v/v) and one of the disaccharides (10 – 20 % w/v). In all experiments, slow cooling provided significantly higher viability if compared to the rapid immersion of the samples into liquid nitrogen.

Short-term Storage of Seeds and Cryopreservation of Embryonic Axes of Lepisanthes fruticosa

Aims: This work highlights short-term storage of recalcitrant Lepisanthes fruticosa seeds and long-term conservation attempts of its embryonic axes (EAs) through cryopreservation.
 Study design: This study adopted the Completely Randomized Design (CRD). Ten samples were used for each experiment and replicated for 3 – 5 times.
 Place and Duration of Study: Cryopreservation Laboratory, Agrobiodiversity and Environment Research Centre, MARDI Headquarters, Malaysia, in 2017 and 2018.
 Methodology: Short-term storage was carried out using fresh seeds at 54% moisture content and stored at 8±1 °C and 25±2 °C for 7 weeks. Three variations to sterilization were attempted to optimize survival while keeping contamination low. Cryopreservation using two different methods were tested, namely vitrification and the encapsulation vitrification method. Vitrification technique involved the pre-culturing of EAs overnight in different sucrose pre-culture concentrations (0, 0.2, 0.4 and 0.6 M) prior to, loading, dehydration with vitrification solution (PVS2), rapid immersion into liquid nitrogen (-196°C), rapid warming, unloading and recovery. While, encapsulation vitrification involved encapsulation of the EAs using 3% sodium alginate followed by exposure to different duration (0, 10, 20, 30, 40 and 50 minutes) of vitrification solution (PVS2) prior to cryopreservation.
 Results: L. fruticosa seeds can be safely stored for short-term up to 7 weeks of storage either at 8±1 °C or 25±2 °C with no loss in germination. This study also showed that EA was amenable to cryopreservation and 13.33 – 66.67% of viability was obtained when the EAs were cryopreserved using the vitrification technique. The best result was obtained with 66.67% viability, when the EAs were pre-cultured with 0.4M sucrose prior to exposure to PVS2 and liquid nitrogen. Cryopreservation of EAs using the encapsulation-vitrification method was unsuccessful.
 Conclusion: Seeds of L. fruticosa can be stored for short-term (up to 7 weeks) using hydrated/non-dried seeds where they can be successfully stored at 8±1 °C and 25±2 °C for up to 7 weeks. For long-term (cryopreservation), EAs can be cryopreserved upon pre-culture with 0.4M sucrose prior to exposure to PVS2 and liquid nitrogen through vitrification technique.

Experimental Study on the Effect of Expansive Agent on the Durability of Concrete in Civil Air Defense Engineering

In this study, the effect of 8% UEA the reason why the UEA content is 8% is as follows: the expansion agent content in the actual mix proportion of the project is 8%, which is selected in this test to fit the reality better. expansion agent on the compressive strength, chloride ion penetration resistance, and carbonation resistance of civil air defense concrete were studied by simulating the rapid carbonation and chloride solution immersion of concrete structure in coastal civil air defense engineering environment. The results of this study show that the early compressive strength of concrete decreased by adding the UEA expansion agent and was also affected by the curing time. Moreover, the addition of UEA expansion agent decreased the content of free chloride ions and calcium carbonate in concrete and reduced the early compressive strength of concrete.

Investigation of the ignition phase in electrolytic plasma polishing under different starting conditions

Electrolytic plasma polishing is a hybrid process in which the electrolytic process is an assisting process for a plasma region, which subsequently cleans and polishes the surface of a workpiece. The basic process takes place in an electrolyte bath, where very different starting conditions can be met. The extreme cases are the ignition in the bath, the ignition during a rapid immersion phase and the ignition in a slow immersion phase. Characteristic of these individual cases are the extreme changes of the tool impedance in connection with the electrolyte. The paper shows how the current-voltage characteristic can be measured, without adjustment problems between the process energy source (PES) and the connection impedance. The individual phases of the ignition phase are explained on the basis of a phenomenological model and the changes in the model (equivalent circuit diagram) of the process are taken into account. From these findings, the conditions can be derived to the PES and energy consumption in the ignition phase can be minimized. The basic objective is also to convert the ignition phase into a stable polishing phase and to have as few re-ignition phases as possible during the polishing period. In particular, the boundary conditions for the Bath-PeP are defined, which allow for a fast polishing of the surface, without deteriorating the mechanical properties of the surface or changing the geometry of the functional surface. In contrast to electrolytic polishing, no edge rounding occurs if a correspondingly short processing time is maintained.

A review of virtual reality videogames for job-training applications

Information and Communication Technologies (ICT) are considered as crucial elements in educational processes, as they constitute relevant and necessary tools in the search for higher levels of socioeconomic development. In this context, ICTs have raised the challenge of finding pedagogical models that maximize their impact on teachers and students. The Business Services and Management Center of the SENA Regional Antioquia has a wide range of technical training programs, for a rapid immersion into the labor market, which implies the use of training technologies to ease the understanding of theoretical concepts and the practice of technical procedures. In addition, these programs require the development of skills allowing their students to perform correctly in the workplace. Considering the above, videogames arise as an alternative tool for training operations. This article presents a review of training tools based on virtual reality, focusing mainly on the design of the game elements and their dynamics, which can contribute to magnify user experiences. Moreover, we present some projects showing success stories in the learning process and discussing the impact of the elements and game mechanics.

Correction of inertance of temperature sensing devices in high-speed flow

The influence of the thermocouple calibration method on the reconstruction of the real temperature in impulse wind tunnel with operation duration of up to 100 ms is presented. It is shown that in an impulse set-up allow obtaining a stepwise thermal load with long temperature plateau which enough to determination of instrumental function, necessary for temperature reconstruction. To this aim, the developed technique, based on the application of the solution of the convolution integral equation, was used. It was included the information on the instrumental function, which was obtained from the calibration measurements. In the deconvolution procedure, the signal was first smoothed by splines, the convolution kernel was extracted by the differentiation of smoothed function, and regularization was performed by Kaczmarz algorithm with relaxation parameter. A comparison is made of the temperature reconstruction in the regular mode of hot shot wind tunnel with two different methods for measuring the response of thermocouples to the temperature step: measurement behind the shock wave front and rapid immersion in aluminum melt. It is found that the use of the instrumental function obtained in a wind tunnel allows one to more reliably determine the position of the temperature maximum in real experiment, which corresponds to the physical structure of the flow.

Role of vasopressin V1 antagonist in the action of vasopressin on the cooling-evoked hemodynamic perturbations of rats

We aimed to investigate the role of arginine vasopressin (AVP) acting via the AVPV1 receptor in the autonomic cardiovascular responses to cold stress (CS). The study was conducted on adult male Sprague-Dawley rats with telemetry transmitters implanted to monitor heart rate (HR) and systolic blood pressure (SBP) throughout the experiment course. Rats were divided into four groups and were given, respectively, saline (control group), AVPV1 antagonist (V1880) alone, and V1880 following the removal of sympathetic outflows using hexamethonium (HEX+V1880) or guanethidine (GUA + V1880). Rats were subjected to the CS stimuli (rapid immersion of the rat's limbs into 4 °C water). Hemodynamic responses were recorded at baseline (PreCS), during CS, and after CS. Data analysis was performed using descriptive methods and spectral and cross-spectral analysis of blood pressure variability (BPV) and heart rate variability (HRV). Key results showed that at PreCS, inhibition of AVPV1 increases SBP and HR as well as very-low-frequency BPV and low-frequency BPV, which is attenuated by hexamethonium (effect on SBP only) and guanethidine (effect on both SBP and HR). HEX+V1880 results in increased high-frequency BPV and attenuated very-low-frequency HRV, while GUA + V1880 results in increased high-frequency HRV and attenuated very-low-frequency HRV. During CS, we observed that SBP and HR, as well as very-low-frequency BPV and low-frequency BPV, were similar in the control group and the group with AVPV1 inhibition, while AVPV1 inhibition results in attenuated high-frequency BPV. Furthermore, we observed that changes produced by AVPV1 inhibition alone were affected differently by HEX+V1880 and GUA + V1880, particularly in low-frequency HRV and very-low-frequency HRV. The results support that AVPV1 mediates autonomic cardiovascular responses at both baseline and CS stimuli conditions are associated with central mechanism engagement.

Pore size tailoring from ultrafiltration to nanofiltration with PVC-g-PDMA via rapid immersion thermal annealing

Different from the typical interfacial polymerization for nanofiltration membrane fabrication, we proposed a novel method to prepare charged nanofiltration membrane via rapid immersion thermal annealing process with the ultrafiltration membrane, which was prepared from the amphiphilic copolymer, poly(vinyl chloride)-g-poly(2-(dimethylamino)ethyl methacrylate) (PVC-g-PDMA) via non-solvent induced phase separation. The pore structures and chemical properties of the membranes, and annealing conditions including the media where the membrane was annealed, annealing temperature and time, were investigated in detail. It is found that the porous separation layer was collapsed to be a stable, defect-free, and smooth film as the dense separation layer of nanofiltration membrane when it was annealed in n-heptane above its glass transition temperature (Tg) for only 1 min while the pore size cutoff was tailored from 20 nm to 2 nm. Salt rejections were in the order of MgCl2 > NaCl > MgSO4 > Na2SO4 at neutral condition due to Donnan repulsion, indicating a typical positively charged nanofiltration membrane. Overall, this rapid immersion thermal annealing process provides a facile and effective strategy to tailor ultrafiltration membrane toward nanofiltration applications for amphiphilic copolymer based membranes.

Characterization of the role of endogenous nitric oxide in myogenic vascular oscillations during cooling-evoked hemodynamic perturbations of rats.

Rapid immersion of a rat's limbs into 4 °C water, a model of cold stress, can elicit hemodynamic perturbations (CEHP). We previously reported that CEHP is highly relevant to sympathetic activation and nitric oxide production. This study identifies the role of nitric oxide in CEHP. Conscious rats were pretreated with the nitric oxide synthase inhibitor L-NAME (NG-nitro-l-arginine methyl ester) alone or following the removal of sympathetic influences using hexamethonium or guanethidine. Rats were then subjected to a 10 min cold-stress trial. Hemodynamic indices were telemetrically monitored throughout the experiment. The analyses included measurements of systolic blood pressure; heart rate; dicrotic notch; short-term cardiovascular oscillations and coherence between blood pressure variability and heart rate variability in regions of very low frequency (0.02-0.2 Hz), low frequency (0.2-0.6 Hz), and high frequency (0.6-3.0 Hz). We observed different profiles of hemodynamic reaction between hexamethonium and guanethidine superimposed on L-NAME, suggesting an essential role for a functional adrenal medulla release of epinephrine under cold stress. These results indicate that endogenous nitric oxide plays an important role in the inhibition of sympathetic activation and cardiovascular oscillations in CEHP.

Envenomation by the invasive Pterois volitans species (lionfish) in the French West Indies – a two-year prospective study in Martinique

Context: The invasion of the lionfish (Pterois volitans) in the French West Indies represents one of the most important marine invasions by alien species in history. Since its first recognition in Martinique in February 2011, the lionfish presence has strongly progressed, resulting in increasing envenomation cases. Our objective was to report features of lionfish envenomation and outcome. Methods: A prospective study conducted at the Martinique University Hospital by the emergency departments, general practitioners, and the pre-hospital emergency ambulance service included all the patients referred from November 2011 to February 2014 for one or several stings by lionfish, as strongly suggested by the fish description and the association with marked local pain and edema. Recommended management included immersion of the affected body part in hot water at 35–40 °C for 60 min, analgesics, tetanus toxoid, and antibiotics. Results: 117 patients [98M/19F; age: 42 ± 14 years [mean ± SD]; with significant past morbidities (16%)] were included. Envenomation resulted in marked pain and local edema (100%), paresthesia (90%), abdominal cramps (62%), extensive edema (53%), tachycardia (34%), skin rash (32%), gastrointestinal disorders (28%), fainting (27%), transient weakness (24%), hypertension (21%), hypotension (18%), hyperthermia (9%), bradycardia (3%), hypophosphatemia (12%), elevated aspartate aminotransferase (AST) (10%), and thrombocytopenia (3%). The sting was complicated by local infection (18%) including skin abscess (5%), cellulitis (3%), skin necrosis (3%), and septic arthritis (2%). 26 patients (22%) were hospitalized requiring surgery (8%). Lionfish stings were single (81%) or multiple (19%). Localization was preferentially at one upper (67%) or lower limb (32%). All patients actually improved. Based on multivariate analyses, pain duration > 24 h was significantly associated with skin eruption (p = 0.001) and muscle cramps (p = 0.0002). Local infectious complications occurred more frequently in patients presenting multiple stings (p = 0.008). Immersion in hot water (44%, performed less than 3 h after the sting in 36% of the cases) significantly reduced pain duration (p = 0.02) and local infection (p = 0.02). Conclusion: Lionfish represents a major health threat in Martinique with increasing envenomation and significant morbidities. Outcome is favorable if promptly managed, with possible reduction in pain duration and local infections with the rapid immersion of the stung body part in hot water. Our data encourage the authorities to develop investigations on the exact extent of the lionfish invasion and set up a regional taskforce to inform the ecosystem users and register all lionfish-attributed incidents.

Spectral analysis of cooling induced hemodynamic perturbations indicates involvement of sympathetic activation and nitric oxide production in rats.

Oscillations in arterial pressure and heart period in response to cold stress are poorly understood. We used a telemetric device with spectral and cross-spectral analyses to assess variabilities in the heart rate (HRV) and blood pressure (BPV) of conscious rats receiving a cooling stimulus (CS) (rapid immersion of palms and soles into 4°C water) at ambient thermoneutral conditions (TC), in a cold room (CC), and when under pentobarbital anesthesia (UA). Power spectra of very low, low, and high frequencies (VLF: 0.02 to 0.2Hz, LF: 0.2 to 0.6Hz, and HF: 0.6 to 3.0Hz), dicrotic notch (Dn) and plasma nitric oxide (NO) levels were measured for statistical comparisons. When compared to resting rats (PreCS), CS evoked in rats the following hemodynamic perturbations: 1) pressor and tachycardia; 2) increases in VLFBPV, LFBPV, HFBPV, and TPBPV but decreases in VLFHRV, LFHRV, and TPHRV; 3) a positive correlation between LFBPV and VLFBPV but an inverse correlation between VLFHRV and VLFBPV and LFHRV and LFBPV; 4) high coherence value at frequency region of LF between BPV and HRV; and 5) increase of NO production and disappearance of Dn. Additionally, CS of CC and UA rats compared with TC rats evoked different patterns of hemodynamic perturbations; CC rats were activated but UA rats were inactivated. Our findings indicate that changes in VLFBPV are related to the myogenic vascular responsiveness to CS. Power spectra changes to CS are highly relevant to sympathetic activation and NO production.