Submersion Time Research Articles

Epidemiology of alcohol-related unintentional drowning: is post-mortem ethanol production a real challenge?

BackgroundPost-mortem (PM) ethanol production may hamper the interpretation of blood alcohol concentration (BAC) in victims of drowning. Different exclusion criteria (e.g. cases with low BAC or with protracted interval between death and toxicological analysis) have been proposed with no factual figures to reduce the potential bias due to PM ethanol production when examining the prevalence rates for alcohol-related drowning. The aim of this study is to verify the extent to which PM alcohol production may affect the accuracy of studies on drowning and alcohol.FindingsUnintentional fatal drowning cases (n = 967) for which a full medico-legal autopsy and toxicological analysis was performed, in Finland, from 2000 to 2013, and relevant variables (demographic data of the victims, month of incident, PM submersion time, blood alcohol concentration, urine alcohol concentration (UAC), vitreous humour alcohol concentration (VAC) were available. Overall, out of 967 unintentional drownings, 623 (64.4%) were positive for alcohol (BAC > 0 mg/dL), 595 (61.5%) had a BAC ≥ 50 mg/dL, and 567 (58.6%) a BAC ≥ 100 mg/dL. Simultaneous measurements, in each victim, of BAC, UAC, and VAC revealed PM ethanol production in only 4 victims (BAC: 25 mg/dL – 48 mg/dL). These false positive cases represented 0.4% of drownings with BAC > 0 mg/dL and 14.3% of drownings with BAC > 0 mg/dL and < 50 mg/dL.ConclusionsThe present study suggests that PM ethanol production has a limited impact on research addressing the prevalence rate for alcohol-related drowning and that the use of too rigorous exclusion criteria, such as those previously recommended, may led to a significant underestimation of actual alcohol-positive drowning cases.

The potential use of gentamicin sulfate-loaded poly(l-lactic acid)-sericin hybrid scaffolds for bone tissue engineering

Poly(l-lactic acid) (PLLA) scaffolds were prepared by a particulate leaching method using sodium chloride (NaCl) with the size of 300–425 µm as a particulate leaching. The PLLA/NaCl weight ratios were varied to be 1:8, 1:10, 1:12, and 1:15. The gentamicin sulfate (GS)-loaded PLLA-sericin hybrid scaffolds were prepared by immersion of the PLLA scaffolds in sericin solution containing GS at a concentration of 5 mg mL−1 and subsequently freeze-drying. From the results, the pore sizes of the neat and the GS-loaded PLLA-sericin hybrid scaffolds ranged between 290 and 346 µm. The pore interconnectivity of these scaffolds increased with an increase in the amount of NaCl. Both the neat and the GS-loaded PLLA-sericin hybrid scaffolds that had been fabricated at PLLA/NaCl weight ratio of 1:15 showed high interconnected porous structure. Both the water retention and the weight loss increased with increasing NaCl content and submersion time. The increase in the porous structure of the scaffolds with the increasing NaCl content resulted in an observed decrease in the compressive modulus. Moreover, the cumulative released amounts of GS increased with increasing the porous structure of the scaffolds. All the GS-loaded PLLA-sericin hybrid scaffolds showed high activity against the growth of both E. coli TISTR 780 and S. aureus TISTR 1466. Lastly, all the GS-loaded PLLA-sericin hybrid scaffolds were proven non-toxic to MC3T3-E1 cells, indicating their potential uses for bone tissue engineering.

Evaluation of Asphalt Effect on Water Quality Using Leaching Test and Molecular Simulation

Abstract The contact of water and asphalt in roadway pavement can lead to the leaching of components from asphalt and cause water contamination. In order to study influencing factors affecting water contamination caused by asphalt materials, leaching tests were performed on asphalt mixture specimens with different mix designs. Chemical oxygen demand (COD), pH value, and total hardness are used to evaluate the leachability of asphalt mixture. The thin film leaching tests were carried out using a self-developed pressurized device. The effects of asphalt type, pH value of water, and submersion time on the concentration of ten metal ions leached from asphalt film were investigated. Finally, molecular dynamics simulations were performed to investigate the molecular diffusion between asphalt components and water. Results indicate that the concentration of metallic elements was affected by the pH value of water and submersion time. Compared with aged and SBS (Styrene-Butadiene-Styrene)–modified asphalt, virgin asphalt has the higher leaching potential for water contamination. The light fractions of aromatic and saturate molecules are more likely to diffuse at high temperature and high pressure. The study results can help better understand the environmental impact of asphalt in the framework of life-cycle assessment.

Effects of reverse seasonal submersion on the germination and persistence of soil seed banks in hydro‐fluctuation belts

AbstractThe construction of the Three Gorges Dam has resulted in the occurrence of reverse seasonal water‐level fluctuations. The species composition and quantity of riparian soil seed banks collected from four hydro‐fluctuation belts were assessed by simulating different submersion cycles to determine the effects of reverse seasonal water‐level fluctuations on the germination and persistence of soil seed banks in the Three Gorges Reservoir Region. Results showed the number of species that germinated from the soil seed bank decreased with submersion. The number of germinated seeds in soil seed banks after submersion for 7 months in Xingshan, Zigui, Wanzhou, and Zhongxian decreased by 60%, 53%, 57%, and 57%, respectively, relative to the control. The species diversity index and seed density of germinated seeds in soil seed banks also significantly decreased with prolongation of submersion time. Seed density decreased by 93%, 83%, 76%, and 72%, respectively, after 7 months of submersion. Species composition and dominance within the soil seed bank changed over time due to submersion. In general, reverse seasonal submersion negatively impacts the germination and persistence of soil seed banks. The response of soil seed bank germination and persistence to reverse seasonal submersion became the key factor determining the heterogeneity in the spatial distribution of the soil seed bank in hydro‐fluctuation belts due to the large differences in submersion time between areas at various elevations.

RESPON PERKECAMBAHAN BENIH KEMIRI SUNAN (Reutealis trisperma) TERHADAP SKARIFIKASI KIMIA DENGAN ASAM SULFAT (H2SO4) PADA BERBAGAI LAMA WAKTU PERENDAMAN

The duration of submersion and the level of acid concentration which are the decisive factors to succed the chemical scarification. The duration of submersion should be adjusted to the level of seed skin thickness, the level of acid concentration and the type of acid used. This study aimed to analyze the inmersion effect of kemiri sunan seeds in sulfuric acid solution to break the seed dormancy and to get the most effective time of submersion in order to break the dormancy of kemiri sunan seed. The experiment was conducted in the greenhouse for 2 months (62 days). The randomized complete design was employed as experimental method. There were 4 treament tested, i.e : (1) control (without immersion in H2SO4 solution); (2) immersion in H2SO4 solution for 10 minutes; (3) immersion in H2SO4 solution for 20 minutes and (4) immersion in H2SO4 solution for 30 minutes. The results of research showed that control gave the best results in term of the percentage of germination (G), mean daily gremination (MDG), and germination rate (GR)

Temperature and Dissolved Oxygen Determine Submersion Time in Aquatic Beetle Peltodytes callosus (Coleoptera: Haliplidae)

Global climate change affects aquatic habitats in a number of ways that pose challenges for aquatic insect populations. Increasing water temperature and corresponding decreases in dissolved oxygen can impact respiratory behaviors, even in air-breathing aquatic taxa. Crawling water beetles (Coleoptera: Haliplidae) exhibit a combined respiratory strategy that employs an air store that is periodically replenished at the water surface. The frequency at which beetles surface to replenish the bubble is determined both by oxygen demand and by the capacity of the air store to uptake oxygen from the surrounding water via diffusion. However, little is known of how changes in water temperature and dissolved oxygen will affect submersion time. We investigated this question in Peltodytes callosus, a species of crawling water beetle that is widely distributed across the American West. We manipulated temperature and dissolved oxygen to mimic changes associated with global climate change and recorded the time between surfacing events. We found that beetles stayed submerged for shorter durations in response to both increasing water temperature and decreasing dissolved oxygen. Our results suggest that beetles may be able to modify their surfacing behavior to respond to climate-induced changes in water quality.

Responses Of Kemiri Sunan (Reutealis trisperma) Seeds Germination To Chemical Scarification Atvarious Submersion Time In Sulfuric Acid (H2so4)

The duration of submersion and the level of acid concentration which are the decisive factors to succed the chemical scarification. The duration of submersion should be adjusted to the level of seed skin thickness, the level of acid concentration and the type of acid used. This study aimed to analyze the inmersion effect of kemiri sunan seeds in sulfuric acid solution to break the seed dormancy and to get the most effective time of submersion in order to break the dormancy of kemiri sunan seed. The experiment was conducted in the greenhouse for 2 months (62 days). The randomized complete design was employed as experimental method. There were 4 treament tested, i.e : (1) control (without immersion in H2SO4 solution); (2) immersion in H2SO4 solution for 10 minutes; (3) immersion in H2SO4 solution for 20 minutes and (4) immersion in H2SO4 solution for 30 minutes. The results of research showed that control gave the best results in term of the percentage of germination (G), mean daily gremination (MDG), and germination rate (GR).

Unmanned aerial vehicles (drones) to prevent drowning

BackgroundDrowning literature have highlighted the submersion time as the most powerful predictor in assessing the prognosis. Reducing the time taken to provide a flotation device and prevent submersion appears of paramount importance. Unmanned aerial vehicles (UAVs) can provide the location of the swimmer and a flotation device. ObjectiveThe objective of this simulation study was to evaluate the efficiency of a UAV in providing a flotation device in different sea conditions, and to compare the times taken by rescue operations with and without a UAV (standard vs UAV intervention). Several comparisons were made using professional lifeguards acting as simulated victims. A specifically-shaped UAV was used to allow us to drop an inflatable life buoy into the water. ResultsDuring the summer of 2017, 28 tests were performed. UAV use was associated with a reduction of time it took to provide a flotation device to the simulated victim compared with standard rescue operations (p < 0.001 for all measurements) and the time was reduced even further in moderate (81 ± 39 vs 179 ± 78 s; p < 0.001) and rough sea conditions (99 ± 34 vs 198 ± 130 s; p < 0.001). The times taken for UAV to locate the simulated victim, identify them and drop the life buoy were not altered by the weather conditions. ConclusionUAV can deliver a flotation device to a swimmer safely and quickly. The addition of a UAV in rescue operations could improve the quality and speed of first aid while keeping lifeguards away from dangerous sea conditions.

The catching efficiency of light traps and morphology of the native species from Barito river, Indonesia

Various fishing gears are being used for harvesting fish and shrimp in Barito River, Indonesia. However, the use of lighted traps is still poorly studied. A set of fishing gears associated with light emitting diode (LED) and incandescent lamps was used as sampling tools. The trials consisted of 113-trap hauls/lamp type using 1-night submersion time of 15 h. The light traps were standardized to a catch per unit effort (CPUE). The light traps sampling accounted for 397 specimens assigned to 11 species of 7 families. There was highly significant difference in the number of catches between shrimp and fish (P<0.001). Shrimp sizes ranged of 24–85 mm total length and 0.3–10 g weight, while for fish 27–310 mm and 0.4–101 g. Yellow and red LED light traps seemed to be effective in catching Macrobrachium rosenbergii as well as white LED ones for Oxyeleotris marmorata. Both species solely showed positive allometric growth type (b = 3.42 and 3.28), while other species displayed negative allometric growth pattern (b = 0.82–2.71) with the condition factor (K) values ranged of 0.36–1.56. A new native species Macrobrachium sp. were found and considered as multichromatic species. The size and shape of the light traps did not affect number of catch. The mean CPUEs for incandescent and LED light traps were 0.07±0.06 and 0.13±0.20 fish net-1 night-1. No significant difference in the relative catching efficiency between both light trap types was observed.

Full neurological recovery following a hypothermic, near-drowning cardiac arrest with a 34 minute submersion time: A case repor

Hypothermia increases the ischemic tolerance of the brain and can lead to a remarkable recovery in prolonged cardiac arrest. Neurological outcomes can be very favorable, particularly if cardiac arrest precedes hypothermia or if the onset of hypothermia following cardiac arrest is rapid. Case reports of good neurological recovery following up to 7 h submersion and core temperatures as low as 13.7°C can be found. Our case involved a 43-year-old male who presented following a collapse and out of hospital cardiac arrest. A 34 min period of face-down submersion in a canal on a cold February evening was followed by a brief period of cardiopulmonary resuscitation on extrication. He was transferred to our emergency department with a core temperature of 26°C. He went onto make a full neurological recovery. The UK’s temperate climate means that case reports of prolonged hypothermic cardiac arrest are rare. While this gentleman had many favorable circumstances to his predicament, including age, cardiovascular fitness and rapid cooling, prompt and effective resuscitation, and a controlled warming regime would also have contributed. Keywords: Hypothermia cardiac arrest, neurological recovery.

PENENTUAN EFISIENSI DYE SENSITIZED SOLAR CELL (DSSC) MENGGUNAKAN EKSTRAK BUAH KAKTUS (Opuntia elatior Mill.)

Dye-Sensitized Solar Cells (DSSC) research by using cactus fruit extract (Opuntia elatior Mill.) has been done. The objectives of the research are to determine the highest efficiency of submersion time and Dye pH treatments of cactus fruit extract (Opuntia elatior Mill.). This research was used a Complete Random Design (CRD) method whereas the submersion time of the worked electrode on five extents of treatments are 6,12,18, 24, 30 hours and Dye pH on four extents of treatments are 1, 3, 5, and 7. The result showed that the optimum time at 12 hours with the Dye pH at 3 has resulted in the highest efficiency of 0.105. Keywords: Cactus fruit extract, Opuntia elatior Mill, efficiency, DSSC.

Catching efficiency of multifilament trammel nets with different twisted twine for shrimp fishing in Kotabaru, Indonesia

Fishing experiments were carried out in Kotabaru of Indonesia to determine catching efficiency of double-twisted and triple-twisted multifilament trammel nets. A total of 10 nets were constructed with the same dimension and inner-outer mesh sizes (40-mm and 80-mm). Trials covered 160-net hauls/type with 1-hour submersion time. The shrimps were composed of Penaeus monodon , Penaeus merguensis , Metapenalis monoserus, Penaeus semiculatus and Parapenaeopsis sculptilis . A total of 142.8 kg shrimp comprises 84.46 kg (59.15%) for double-twisted and 58.34 kg (40.85%) for triple-twisted were collected over 16-daytrip sampling period, indicating double-twisted multifilament trammel net was 45% more efficient. The average weight of double-twisted (5.25±1.64 kg) was considerably higher than that of triple-twisted (3.65±1.41 kg) as well as total YPUE of double-twisted (1.056±0.02 kg) was considerably higher than that of triple-twisted (0.729±0.02 kg) ( P <0.05). Some recommendations for improving performances and efficiency of trammel nets are made, for example, by inserting the additional bag collector along the lower part of the nets, placing selvedge between the lead line and the net or using underwater lamps associated with the net.

Effectiveness of Diesel as a Mammal Repellent for Direct Seeding of Acorns

The assisted regeneration of oaks can be achieved through seeding or planting. Whereas direct seeding of acorns has several advantages over planting nursery-grown seedlings, the problem of seed predation by mammals precludes its widespread application. We investigated the potential of diesel as a mammal repellent to prevent the consumption of Holm oak acorns. We tested the effect of submerging acorns in diesel for 0, 6, 12, and 24 h on acorn predation in a field experiment in the Sierra Nevada Natural Park (Granada province, Spain), and the potential effect of the same treatments on seedling emergence and growth in a nursery experiment. The field experiment showed no reduction in acorn predation through diesel. On the other hand, submersion in diesel hindered the germination of one in every four sown acorns regardless of submersion time. Our results are in line with many failed attempts to protect acorns with chemical repellents and suggest that an effective, universally-abundant, inexpensive, and easy-to-apply acorn protector to enhance the success of seeding operations is yet to be found.

Management System for Dam-Break Hazard Mapping in a Complex Basin Environment

Flood disasters from dam breaks cause serious loss of human life and immense damage to infrastructure and economic stability. The application of Geographic Information System technology integrated with hydrological modeling for mapping flood-inundated areas and depth can play a momentous role in further minimizing the risk and possible damage. In the present study, base terrain data, hydrological data, and dam engineering data were integrated using the MIKE-21 dam-break model to analyze flood routing under the most serious scenarios. A deterministic approach was used to calculate the hydraulic elements of dam breakage during a flood. Additionally, the hydraulic elements generated by the MIKE-21 dam-break model (a modelling system for estuaries, coastal waters, and seas)—including flood depth, submersion time, and flow direction—were integrated with a digital elevation model of the site downstream of the dam in order to map the possible affected areas. Using an empirical model in addition to using the superimposition of dam flood calculation results and the social and economic survey data, dam damage assessment was implemented. In accordance with a relevant standard, the flood risk mapping guidelines and a set of client/server structures were developed for a management system for dam-break hazard mapping of the Foziling reservoir. The simulation data and the study results can provide a scientific basis for emergency management of the reservoir and provide a socio-economic framework for downstream areas.

Exceptional flooding tolerance in the totipotent recalcitrant seeds ofEugenia stipitata

AbstractEugenia stipitataoccurs along rivers in Western Amazonia and produces berry-type fruits with economic potential. Its large recalcitrant (i.e. desiccation-intolerant) seeds have been proposed as a model to study seed stress response, as no apparent differentiation between the embryonic axis and the fused cotyledons are visible. Here, the longevity of submerged seeds was analysed with a view to understanding adaptive mechanisms to seasonal flooding. Submerged seeds began germinating after 2 months. After 1 year, 87 and 96% total germination was reached when seeds were submerged under a water column of 6 cm (where seedlings could emerge from under the water) and 26 cm (where seedlings could not reach the water surface), respectively. Seedling morphology was altered underwater, with short internodes and rudimentary leaf blades, and when submersion was terminated, seedlings transplanted to nursery conditions recovered a normal phenotype. Furthermore, when seedlings were detached from the seeds, the ‘resown’ seeds produced a second, normal seedling within 9 months. Concentrations of the antioxidant glutathione, which was measured as a stress marker, increased with submersion time in water. Seeds that had developed roots and shoots underwater had higher concentrations of glutathione disulphide than non-germinated seeds, suggesting that the flooding stress was more intense for seedlings than seeds, although more oxidizing cellular redox environments are also consistent with the conditions required for differentiation. Submergence underwater is recommended for storage of the recalcitrant seeds ofE. stipitatafor up to 1 year.

Submersion of the system «anchor-tightrope» of longline

A hydrodynamic problem for the longline system «anchor-tightrope» in resting fluid is formulated and solved on base of the theory of dynamics for systems with variable mass. The system of initial differential equations is solved by means of numerical methods using the software designed in MathCad-14 environment; parameters of the «anchor-tightrope» system in the process of submersion are calculated. Dependence of the time and velocity of submersion on type of anchor is analyzed taking into account the hydrodynamic forces dependence on Reynolds number. Influence of inertia force is determined. Cited results for dependence of the submersion time for fishing gear elements on depth are overviewed.

Blood pooling in extrathoracic veins after glossopharyngeal insufflation

Trained breath-hold divers hyperinflate their lungs by glossopharyngeal insufflation (GPI) to prolong submersion time and withstand lung collapse at depths. Pulmonary hyperinflation leads to profound hemodynamic changes. Thirteen divers performed preparatory breath-holds followed by apnea with GPI. Filling of extrathoracic veins was determined by ultrasound and magnetic resonance imaging and peripheral extravasation of fluid was assessed by electrical impedance. Femoral vein diameter was measured by ultrasound throughout the easy-going and struggle phase of apnea with GPI in eight divers in a sub-study. After GPI, pulmonary volume increased by 0.8 ± 0.6L above total lung capacity. The diameter of the superior caval (by 36 ± 17%) and intrathoracic part of the inferior caval vein decreased (by 21 ± 16%), while the diameters of the internal jugular (by 53 ± 34%), hepatic (by 28 ± 40%), abdominal part of the inferior caval (by 28 ± 28%), and femoral veins (by 65 ± 50%) all increased (P < 0.05). Blood volume of the internal jugular, the hepatic, the abdominal part of the inferior caval vein, and the combined common iliac and femoral veins increased by 145 ± 115, 80 ± 88, 61 ± 60, and 183 ± 197%, respectively. In the sub-study, femoral vein diameter increased by 44 ± 33% in the easy-going phase of apnea with GPI, subsequently decreasing by 20 ± 16% during the struggle phase. Electrical impedance remained unchanged over the thigh and forearm, thus excluding peripheral fluid extravasation. GPI leads to heart and pulmonary vessel compression, resulting in redistribution of blood to extrathoracic capacitance veins proximal to venous valves. This is partially reversed by the onset of involuntary breathing movements.

Further investigations into the single metal deposition (SMD II) technique for the detection of latent fingermarks

Single metal deposition (SMD II), a recently proposed method for the development of latent fingermarks, was investigated by systematically altering aspects of the procedure to assess their effect on the level of development and contrast achieved. Gold nanoparticle size, temperature of the deposition solution bath, and orbital shaking during detection were shown to affect the levels of development and contrast obtained. Gold nanoparticles of diameter 15–21nm were found to be most effective for satisfactory visualisation of latent fingermarks, while solutions that were applied at room temperature were found to adequately balance the ratio between the contrast of the fingermark ridge detail and the level of background staining achieved. Finally, optimum levels of development and contrast were obtained through constant agitation of both solution baths at approximately 50RPM throughout the submersion time. SMD II was also tested on a large variety of substrate types and shown to be effective on a range of porous, non-porous, and semi-porous surfaces; however, the detection quality can be significantly influenced by the substrate nature. This resulted in the production of dark grey, white, or gold coloured fingermarks on different surfaces, as well as reversed detection on certain types of plastic, similarly seen through the use of vacuum metal deposition.

A new remote sensing method for high-resolution quantification of submersion regimes in wave exposed shores

The importance of the submersion regime for the physiology, behavior and ecology of intertidal organisms, as well as limitations of available measurement methods, motivated us to develop a new remote sensing method. This new method is based on video monitoring of visual references installed at interest positions in the intertidal zone. Video imagery processing algorithms discriminate between states of submersion and emersion. The signal is based on the fluctuation in the color contrast between the visual reference and the adjacent rock. Our remote sensing method was validated favorably by comparing with direct field observations of submersion time series and comparison of different submersion metrics, including submersion percentage and maximum emersion duration. Since the remote sensing method captures and stores imagery remotely, obtaining long records of high temporal resolution is facilitated and the risk of discontinuity of time series is reduced in comparison to the use of sensors at the zone of wave impact. The high temporal resolution is critical for environments with high exposure to waves and allows for reliable estimates of a wide variety of relevant submersion metrics. This low cost remote sensing method should encourage quantification of submersion regimes of organisms inhabiting rocky intertidal zones, as well as the exploration of physiological, behavioral and ecological consequences of these regimes. Identifying the character of the forces underlying submersion regimes, together with critical environmental variables, such as temperature and solar radiation, will allow better hind-casts and forecasts of the ecological consequences of past and future climate change on these communities.

Influence of Temperature Differential between Tomatoes and Postharvest Water on Salmonella Internalization

Salmonella bacteria may internalize into tomato pulp when warm tomatoes from the field are submerged into colder water. Several washing steps may follow the initial washing and packing of tomatoes at the packinghouses; the potential for internalization into tomatoes in subsequent washing steps when tomatoes have a cooler pulp temperature is unknown. Our objective was to evaluate Salmonella internalization into mature green and red tomatoes with ambient (21°C) and refrigeration (4°C) pulp temperatures when they were submerged into water at various temperature differentials, simulating repacking and fresh-cut operations. Red (4°C and 21°C) and mature green (21°C) tomatoes were submerged (6 cm) into a six-strain Salmonella cocktail (6 log CFU/ml) and maintained at ±5 and 0°C temperature differentials for varying time intervals, ranging from 30 s to 5 min. Following submersion, tomatoes were surface sterilized using 70% ethanol, the stem abscission zone and blossom end epidermis were removed, and cores were recovered, separated into three segments, and analyzed. Salmonella populations in the segments were enumerated by most probable number (MPN). The effects of temperature differential and maturity on Salmonella populations were analyzed; results were considered significant at a P value of ≥0.5. Internalized populations were not significantly different (P ≥0.5) across temperature differentials. Salmonella internalization was seen in tomatoes under all treatment conditions and was highest in the segment immediately below the stem abscission zone. However, populations were low (typically >1 log MPN per segment) and varied greatly across temperature differentials. This suggests that the temperature differential between tomatoes and water beyond the initial packinghouse may be less important than submersion time in Salmonella internalization.