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1.
Int J Mol Sci ; 25(5)2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38474303

RESUMO

Underwater activities are characterized by an imbalance between reactive oxygen/nitrogen species (RONS) and antioxidant mechanisms, which can be associated with an inflammatory response, depending on O2 availability. This review explores the oxidative stress mechanisms and related inflammation status (Oxy-Inflammation) in underwater activities such as breath-hold (BH) diving, Self-Contained Underwater Breathing Apparatus (SCUBA) and Closed-Circuit Rebreather (CCR) diving, and saturation diving. Divers are exposed to hypoxic and hyperoxic conditions, amplified by environmental conditions, hyperbaric pressure, cold water, different types of breathing gases, and air/non-air mixtures. The "diving response", including physiological adaptation, cardiovascular stress, increased arterial blood pressure, peripheral vasoconstriction, altered blood gas values, and risk of bubble formation during decompression, are reported.


Assuntos
Mergulho , Oxigênio , Humanos , Mergulho/fisiologia , Nitrogênio , Hipóxia , Inflamação
2.
Eur J Appl Physiol ; 124(6): 1693-1702, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38189825

RESUMO

PURPOSE: Dive-induced cardiac and hemodynamic changes are caused by various mechanisms, and they are aggravated by cold water. Therefore, aging divers with pre-existing cardiovascular conditions may be at risk of acute myocardial infarction, heart failure, or arrhythmias while diving. The aim of this study was to assess the effect of a single decompression CCR dive in arctic cold water on cardiac function in Finnish technical divers. METHODS: Thirty-nine divers performed one identical 45 mfw CCR dive in 2-4 °C water. Hydration and cardiac functions were assessed before and after the dive. Detection of venous gas embolization was performed within 120 min after the dive. RESULTS: The divers were affected by both cold-water-induced hemodynamic changes and immersion-related fluid loss. Both systolic and diastolic functions were impaired after the dive although the changes in cardiac functions were subtle. Venous inert gas bubbles were detected in all divers except for one. Venous gas embolism did not affect systolic or diastolic function. CONCLUSION: A single trimix CCR dive in arctic cold water seemed to debilitate both systolic and diastolic function. Although the changes were subtle, they appeared parallel over several parameters. This indicates a real post-dive deterioration in cardiac function instead of only volume-dependent changes. These changes are without a clinical significance in healthy divers. However, in a population with pre-existing or underlying heart problems, such changes may provoke symptomatic problems during or after the dive.


Assuntos
Temperatura Baixa , Descompressão , Mergulho , Humanos , Mergulho/fisiologia , Masculino , Adulto , Pessoa de Meia-Idade , Descompressão/métodos , Feminino , Coração/fisiologia , Coração/fisiopatologia , Hemodinâmica/fisiologia
3.
Bioresour Technol ; 394: 130266, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38159815

RESUMO

A recycled-gas closed-circuit culture system was developed for safe autotrophic cultivation of a hydrogen-oxidizing, polyhydroxyalkanoate (PHA)-producing Ralstonia eutropha, using a non-combustible gas mixture with low-concentration of H2 supplied by water electrolysis. Automated feedback regulation of gas flow enabled input of H2, CO2, and O2 well balanced with the cellular demands, leading to constant gas composition throughout the cultivation. The engineered strain of R. eutropha produced 1.71 g/L of poly(3-hydroxybutyrate-co-12.5 mol% 3-hydroxyhexanoate) on a gas mixture of H2/CO2/O2/N2 = 4:12:7:77 vol% with a 69.2 wt% cellular content. Overexpression of can encoding cytosolic carbonic anhydrase increased the 3HHx fraction up to 19.6 mol%. The yields of biomass and PHA on input H2 were determined to be 72.9 % and 63.1 %, corresponding to 51.0 % and 44.2 % yield on electricity, respectively. The equivalent solar-to-biomass/PHA efficiencies were estimated to be 2.1-3.8 %, highlighting the high energy conversion capability of R. eutropha.


Assuntos
Caproatos , Cupriavidus necator , Poli-Hidroxialcanoatos , Fermentação , Cupriavidus necator/genética , Dióxido de Carbono , Gases , Eletrólise
4.
Undersea Hyperb Med ; 50(4): 391-393, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38055879

RESUMO

Closed-circuit rebreather diving is becoming more common. Rebreathers are complicated, adding to the stress of diving. Also adding to this complexity in the presented case is diving at a high-altitude, cold-water reservoir in Colorado. One diver experienced an oxygen-induced seizure at depth. The other diver had a rapid ascent with loss of consciousness. In this case, two experienced divers recovered from a possible devastating dive. Fortunately, they both returned to their pre-dive baseline health. Dive plan- ning is important, but as in this case, dive execution is paramount. This is a clinical case for an uncommon event presenting to an emergency department.


Assuntos
Mergulho , Oxigênio , Mergulho/efeitos adversos , Altitude
5.
Onco Targets Ther ; 16: 143-155, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36911533

RESUMO

Cancer cells strongly upregulate glucose uptake and glycolysis to produce vital biomolecules for cancer cell survival, proliferation, and metastasis as ATP, lipids, proteins, nucleotides, and lactate. The Warburg effect is tumours' unique glucose oxidation to give lactate (not pyruvate) even in the presence of oxygen. Nicotinamide adenine dinucleotide (NAD/NADH.H) is used in glycolysis via glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and lactate dehydrogenase (LDH). Both catalyse reversible biochemical reactions to produce 1,3-diphosphoglycerate and lactate, respectively. In this expert opinion and based on published evidence, the author suggests that: "In transformed cells and hyperglycolytic cancer cells, the Warburg effect (permanent conversion of pyruvate to lactate) occurs secondary to a vicious cycle and a closed circuit between GAPDH and LDH (reaction of carcinogenesis) causing increased endogenous oxidative stress and subsequent carcinogenesis. Mitochondrial defects in cancer cells cause hyperglycolysis resulting in NADH.H accumulation (produced during GAPDH step) that obligatorily drives LDH to become an irreversible reaction in the direction of lactate formation (Warburg effect) but not pyruvate formation. Likewise, LDH oxidizes NADH.H producing excessive NAD+ that secondarily drives GAPDH reaction to be irreversible to produce NADH.H and so on. Pyruvate is an antioxidant while lactate is pro-oxidant, causing increased endogenous oxidative stress in cancer cells, tumour's hypoxia and obligatory hyperglycolysis with NADH.H overproduction (GAPDH step) to be consumed in the LDH step for lactate production and NAD+ generation (utilized by GAPDH) and so on". This confirms Warburg's origin of cancer cells. Best anticancer applications based on this hypothesis are: breaking this closed vicious circle using siRNA to target GAPDH and LDH, avoiding strong oxidants (as many cancer chemotherapeutics), and using strong antioxidants for causing antioxidant-oxidant antagonism or antioxidant-lactate antagonism to inhibit the Warburg effect. Strong natural antioxidants of prophetic medicine (related to Prophet Muhammad peace be upon him) such as Zamzam water, Nigella sativa, costus, Ajwa date fruit, olive oil, Al-hijamah and natural honey are strongly recommended to prevent and antagonize the Warburg effect.

6.
Korean J Anesthesiol ; 76(1): 17-33, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-35859301

RESUMO

BACKGROUND: The application of a heated-humidified breathing circuit (HHBC) may reduce respiratory heat loss during mechanical ventilation, but its effect in preventing intraoperative hypothermia is controversial. This study aimed to investigate the effectiveness of HHBC in maintaining the core temperature of patients receiving mechanical ventilation under general anesthesia. METHODS: We searched MEDLINE, Embase, Cochrane library (CENTRAL), and Google Scholar to identify all randomized controlled trials (RCTs) up to February 2022 that compared the intraoperative core temperature in patients with heated humidifier (HH) and other circuit devices. The primary outcome was the intraoperative core temperature at the end of surgery. The weighted mean differences (WMDs) between the groups and their 95% CIs were calculated for each outcome. We performed a trial sequential analysis of the primary outcomes to assess whether our results were conclusive. RESULTS: Eighteen RCTs with 993 patients were included in the analysis. A significantly higher core temperature was observed at the end of surgery in patients with HH than those with no device (WMD = 0.734, 95% CI [0.443, 1.025]) or heat and moisture exchanger (WMD = 0.368, 95% CI [0.118, 0.618]), but with substantial heterogeneity. CONCLUSIONS: Although HHBC did not absolutely prevent hypothermia, this meta-analysis suggests that it can be used as an effective supplemental device to maintain the intraoperative core temperature under general anesthesia. However, considering the substantial heterogeneity and limitations of this study, further well-designed studies are needed to clarify the effectiveness of HHBC.


Assuntos
Hipotermia , Humanos , Hipotermia/prevenção & controle , Temperatura Corporal , Temperatura Alta , Respiração Artificial , Anestesia Geral
7.
CNS Neurosci Ther ; 29(1): 8-23, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36229994

RESUMO

Treatment for brain diseases has been disappointing because available medications have failed to produce clinical response across all the patients. Many patients either do not respond or show partial and inconsistent effect, and even in patients who respond to the medications have high relapse rates. Brain stimulation has been seen as an alternative and effective remedy. As a result, brain stimulation has become one of the most valuable therapeutic tools for combating against brain diseases. In last decade, studies with the application of brain stimulation techniques not only have grown exponentially but also have expanded to wide range of brain disorders. Brain stimulation involves passing electric currents into the cortical and subcortical area brain cells with the use of noninvasive as well as invasive methods to amend brain functions. Over time, technological advancements have evolved into the development of precise devices; however, at present, most used noninvasive techniques are repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), whereas the most common invasive technique is deep brain stimulation (DBS). In the current review, we will provide an overview of the potential of noninvasive (rTMS and tDCS) and invasive (DBS) brain stimulation techniques focusing on the treatment of mental, psychiatric, and cognitive disorders.


Assuntos
Encefalopatias , Disfunção Cognitiva , Estimulação Transcraniana por Corrente Contínua , Humanos , Estimulação Transcraniana por Corrente Contínua/métodos , Estimulação Magnética Transcraniana/métodos , Encéfalo/fisiologia , Disfunção Cognitiva/etiologia
8.
Heliyon ; 8(9): e10645, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36164534

RESUMO

Purpose: While schools worldwide have employed closed-circuit television (CCTV) to discourage school violence, the literature shows that stakeholder attitudes toward adopting this technology are inconsistent across cultures. Generally, they are concerned with effectiveness, necessity, privacy, and operational transparency. Based on the Technology Acceptance Model for Video Surveillance (TAM-VS) theory, this study examined the attitudes of educational stakeholders, namely educators and students, toward adopting CCTV in Vietnam. This study aims to investigate which criteria Vietnamese stakeholders use to evaluate the necessity of CCTV and whether the concerns of Vietnam, a developing country, are similar to those of developed countries. Methods: This study addressed these research questions by purposely sampling and interviewing 49 Vietnamese high school students, recent high school graduate students, teachers, and administrators. It employed semi-structured and in-depth interviews to gather content-rich data and applied thematic analysis to discover new insights from stakeholders under the modified TAM-VS framework. The study also followed the COREQ guidelines to improve the transparency and rigor of the data collection and analysis. Findings: On an exploratory basis, most Vietnamese stakeholders believed that while CCTV cannot comprehensively prevent school violence, its effectiveness overshadows privacy concerns. Regarding operational transparency concerns, participants suggested that better communication, consent collection, and the right to amend school policies related to CCTV are important. From the participants' perspective, the three criteria for evaluating the necessity of CCTV were (1) its effectiveness in controlling school violence, (2) serving other purposes to enhance overall schooling performance, and (3) insufficient existing methods. Conclusions: This study provides context-rich insights into the perceptions of the necessity, effectiveness, privacy, and operational transparency concerns of CCTV across different stakeholders in the education and developing country context. On the practical contribution, the research identifies strategies that school administrators can employ to promote CCTV acceptance in Vietnamese high schools.

9.
J Environ Manage ; 318: 115503, 2022 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-35752004

RESUMO

Spent carbon cathode (SCC) as a hazardous solid waste produced in aluminum electrolysis industry, contains plenty valuable components but generate a seriously threat to the environment. This paper focus on a closed-circuit cycle process for direct treatment of SCC based on the hydrothermal acid-leaching method. Thermodynamic calculation, single factor experiment, orthogonal experiment and kinetic study are utilized to obtain the leaching properties of impurities, optimize the leaching conditions, study the influence of conditions on leaching, and capture the restriction factors of leaching. The results indicate that the carbon content of the treated SCC can reach 97.3% when the leaching condition attach the optimal (liquid-solid ratio of 25 mL/g, temperature of 413 K, time of 270 min and acid concentration of 4 mol/L), and liquid-solid ratio is regarded as the crucial factor influencing on that. In addition, the activation energy of impurities reaches 6.25 kJ/mol and the whole leaching process is controlled by the diffusion extent. Finally, the filtrate after the hydrothermal acid leaching is treated, and calcium fluoride, cryolite and sodium chloride are successfully separated. The proposed process eliminates the harm of SCC to the environment, and completes a closed-circuit cycle for the treatment of SCC and recovery of valuable components. It enriches the hydrometallurgical processes of SCC, and provides an attractive scheme for the treatment of SCC.


Assuntos
Fontes de Energia Elétrica , Lítio , Carbono , Eletrodos , Resíduos Perigosos , Reciclagem/métodos
10.
Arch Public Health ; 80(1): 141, 2022 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-35585634

RESUMO

BACKGROUND: Hand hygiene compliance by health care workers (HCWs) is pivotal in controlling and preventing health care associated infections. The aim of this interventional study is to assess the long-term impact of personal verbal feedback on hand hygiene compliance of HCWs in an intensive care unit (ICU) immediately after overt observation by an infection control nurse. METHODS: An infection control nurse overtly observed HCWs' hand hygiene compliance and immediately gave personal verbal feedback with emphasis on aseptic technique. Overt non-interventional sessions were also performed. We measured compliance rates using covert continuous closed-circuit television (CCTV) monitoring. We compared these rates to previously-published hand hygiene compliance data. RESULTS: Overall compliance rates in the first (41.5%) and third phases (42%) of the study, before and after the intervention were similar. The two moments that were lowest in the first phase, "before aseptic contact" and "after exposure to body fluids", showed significant improvement, but two moments showed a significant decline in compliance: "before patient contact" and "after contact with patient surrounding". The compliance rates during the intervention phase were 64.8% and 63.8% during the sessions with and without immediate verbal personal feedback, respectively. CONCLUSION: The overall hand hygiene compliance rate of HCWs did not show an improvement after immediate verbal personal feedback. Covert CCTV observational sessions yielded much lower hand hygiene compliance rates then overt interventional and non-interventional observations. We suggest that a single intervention of personal feedback immediately after an observational session is an ineffective strategy to change habitual practices.

11.
J Clin Monit Comput ; 36(6): 1647-1655, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35103886

RESUMO

Memsorb™ (DMF Medical, Halifax, Canada) is a novel device based upon membrane oxygenator technology designed to eliminate CO2 from exhaled gas when using a circle anesthesia circuit. Exhaled gases pass through semipermeable hollow fibers and sweep gas flowing through these fibers creates a diffusion gradient for CO2 removal. In vivo Memsorb™ performance was tested during target-controlled closed-circuit anesthesia (TCCCA) with desflurane in O2/air using a Zeus IE® anesthesia workstation (Dräger, Lübeck, Germany). Clinical care protocols for using this novel device were guided by in vitro performance results from a prior study (submitted simultaneously). After IRB approval, written informed consent was obtained from 10 ASA PS I-III patients undergoing robot-assisted radical prostatectomy. TCCCA targets were 39% inspired O2 concentration (FIO2) and 5.0% end-expired desflurane concentration (FETdes). Minute ventilation (MV) was adjusted to maintain 4.5-6.0% FETCO2. The O2/air (40% O2) sweep flow into the Memsorb™ was manually adjusted in an attempt to keep inspired CO2 concentration (FICO2) ≤ 0.8%. The following data were collected: FIO2, FETdes, FICO2, FETCO2, MV, fresh gas flow (FGF, O2 and air), sweep flow, and cumulative desflurane usage (Vdes). Vdes of the Zeus IE®-Memsorb™ combination was compared with historical Vdes observed in a previous study when soda lime (DrägerSorb 800 +) was used. Results are reported as median and inter-quartiles. A combination of manually adjusting sweep flow (26 [21,27] L/min) and MV sufficed to maintain FICO2 ≤ 0.8% and FETCO2 ≤ 6.0%, except in one patient in whom the target Zeus IE® FGF had to be increased to 0.7 L/min for 6 min. FIO2 and FETdes were maintained close to their targets. Zeus IE® FGF after 5 min was 0 [0,0] mL/min. Average Vdes after 50 min was higher with Memsorb™ (20.3 mL) compared to historical soda lime canister data (12.3 mL). During target-controlled closed-circuit anesthesia in patients undergoing robot-assisted radical prostatectomy, the Memsorb™ maintained FICO2 ≤ 0.8% and FETCO2 ≤ 6.0%, and FIO2 remained close to target. Modest amounts of desflurane were lost with the use of the Memsorb™. The need for adjustments of sweep flow, minute ventilation, and occasionally Zeus IE® FGF indicates that the Memsorb™ system should preferentially be integrated into an automated closed-loop system.


Assuntos
Anestesia com Circuito Fechado , Anestésicos Inalatórios , Masculino , Humanos , Desflurano , Dióxido de Carbono , Hidróxido de Sódio
12.
J Clin Monit Comput ; 36(6): 1591-1600, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35089526

RESUMO

Soda lime-based CO2 absorbents are safe, but not ideal for reasons of ecology, economy, and dust formation. The Memsorb™ is a novel CO2 removal device that uses cardiopulmonary bypass oxygenator technology instead: a sweep gas passes through semipermeable hollow fibers, adding or removing gas from the circle breathing system. We studied the in vitro performance of a prototype Memsorb™ used with a Zeus IE® anesthesia machine when administering sevoflurane and desflurane in O2/air mixtures. The Zeus IE® equipped with Memsorb™ ventilated a 2L breathing bag with a CO2 inflow port in its tip. CO2 kinetics were studied by using different combinations of CO2 inflow (VCO2), Memsorb™ sweep gas flow, and Zeus IE® fresh gas flow (FGF) and ventilator settings. More specifically, it was determined under what circumstances the inspired CO2 concentration (FICO2) could be kept < 0.5%. O2 kinetics were studied by measuring the inspired O2 concentration (FIO2) resulting from different combinations of Memsorb™ sweep gas flow and O2 concentrations, and Zeus IE® FGFs and O2 concentrations. Memsorb™'s sevoflurane and desflurane waste was determined by measuring their injection rates during target-controlled closed-circuit anesthesia (TCCCA), and were compared to historical controls when using a soda lime absorbent (Draegersorb 800+) under identical conditions. With 160 mL/min VCO2 and 5 L/min minute ventilation (MV), lowering the sweep gas flow at any fixed Zeus IE® FGF increased FICO2 in a non-linear manner. Sweep gas flow adjustments kept FICO2 < 0.5% over the entire Zeus IE® FGF range tested with VCO2 up to 280 mL/min; tidal volume and respiratory rate affected the required sweep gas flow. At 10 L/min MV and low FGF (< 1.5 L/min), even a maximum sweep flow of 43 L/min was unable to keep FICO2 ≤ 0.5%. When the O2 concentration in the Zeus IE® FGF and the Memsorb™ sweep gas flow differed, FIO2 drifted towards the sweep gas O2 concentration, and more so as FGF was lowered; this effect was absent once FGF > minute ventilation. During sevoflurane and desflurane TCCCA, the Zeus IE® FGF remained zero while agent usage per % end-expired agent increased with increasing end-expired target agent concentrations and with a higher target FIO2. Agent waste during target-controlled delivery was higher with Memsorb™ than with the soda lime product, with the difference remaining almost constant over the FGF range studied. With a 5 L/min MV, Memsorb™ successfully removes CO2 with inflow rates up to 240 mL/min if an FICO2 of 0.5% is accepted, but at 10 L/min MV and low FGF (< 1.5 L/min), even a maximum sweep flow of 43 L/min was unable to keep FICO2 ≤ 0.5%. To avoid FIO2 deviating substantially from the O2 concentration in the fresh gas, the O2 concentration in the fresh gas and sweep gas should match. Compared to the use of Ca(OH)2 based CO2 absorbent, inhaled agent waste is increased. The device is most likely to find its use integrated in closed loop systems.


Assuntos
Anestesia com Circuito Fechado , Anestésicos Inalatórios , Humanos , Sevoflurano , Dióxido de Carbono , Desflurano
13.
J Clin Med ; 10(23)2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34884358

RESUMO

Mechanically ventilated patients periodically require endotracheal suctioning. There are conflicting data regarding the loss of lung gas volume caused by the application of a negative pressure by closed-circuit suctioning. The aim of this study was to evaluate the effects of suctioning performed by a closed-circuit system in ARDS patients during volume- or pressure-controlled ventilation. In this prospective crossover-design study, 18 ARDS patients were ventilated under volume and pressure control applied in random order. Gas exchange, respiratory mechanics and EIT-derived end-expiratory lung volume (EELV) before the suctioning manoeuvre and after 5, 15 and 30 min were recorded. The tidal volume and respiratory rate were similar in both ventilation modes; in volume control, the EELV decreased by 31 ± 23 mL, 5 min after the suctioning, but it remained similar after 15 and 30 min; the oxygenation, PaCO2 and respiratory system elastance did not change. In the pressure control, 5 min after suctioning, EELV decreased by 35 (26-46) mL, the PaO2/FiO2 did not change, while PaCO2 increased by 5 and 30 min after suctioning (45 (40-51) vs. 48 (43-52) and 47 (42-54) mmHg, respectively). Our results suggest minimal clinical advantages when a closed system is used in volume-controlled compared to pressure-controlled ventilation.

14.
Eur J Appl Physiol ; 121(12): 3323-3331, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34435274

RESUMO

PURPOSE: Deep diving using mixed gas with closed-circuit rebreathers (CCRs) is increasingly common. However, data regarding the effects of these dives are still scarce. This preliminary field study aimed at evaluating the acute effects of deep (90-120 msw) mixed-gas CCR bounce dives on lung function in relation with other physiological parameters. METHODS: Seven divers performed a total of sixteen open-sea CCR dives breathing gas mixture of helium, nitrogen and oxygen (trimix) within four days at 2 depths (90 and 120 msw). Spirometric parameters, SpO2, body mass, hematocrit, short term heart rate variability (HRV) and critical flicker fusion frequency (CFFF) were measured at rest 60 min before the dive and 120 min after surfacing. RESULTS: The median [1st-3rd quartile] of the forced vital capacity was lower (84% [76-93] vs 91% [74-107] of predicted values; p = 0.029), whereas FEV1/FVC was higher (98% [95-99] vs 95% [89-99]; p = 0.019) after than before the dives. The other spirometry values and SpO2 were unchanged. Body mass decreased from 73.5 kg (72.0-89.6) before the dives to 70.0 kg (69.2-85.8) after surfacing (p = 0.001), with no change of hematocrit or CFFT. HRV was increased as indicated by the higher SDNN, RMSSD and pNN50 after than before dives. CONCLUSION: The present observation represents the first original data regarding the effects of deep repeated CCR dives. The body mass loss and decrease of FVC after bounce dives at depth of about 100 msw may possibly impose an important physiological stress for the divers.


Assuntos
Mergulho/fisiologia , Hélio , Nitrogênio , Oxigênio , Adulto , Desenho de Equipamento , Frequência Cardíaca/fisiologia , Humanos , Masculino , Projetos Piloto , Dispositivos de Proteção Respiratória , Espirometria , Volume de Ventilação Pulmonar
15.
Materials (Basel) ; 14(7)2021 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33918410

RESUMO

Al-Zn-In alloys having 4.2% zinc content and various indium content in the range of 0.02-0.2% were tested with respect to the most important electrochemical properties of sacrificial anodes in a cathodic protection, i.e., the current capacity and potential of the operating anode. The distribution of In and Zn in the tested alloys was mapped by means of the EDX technique, which demonstrated that these elements dissolve well in the alloy matrix and are evenly distributed within it. The current capacity of such alloys was determined by means of the method of determining the mass loss during the dissolution by a current of known charge. The results obtained demonstrate that the current capacity of Al-Zn-In alloy decreases with the increase in the In content, which results in an increased consumption of anode material and shorter lifetime of anodes. With 0.02% In content, the capacity amounted to approx. 2500 Ah/kg, whereas the alloy with 0.2% In had as much as 30% lower capacity amounting to approx. 1750 Ah/kg. Microscopic examination for the morphology and surface profile of the samples after their exposure demonstrated that a higher indium content in the alloy results in a more uneven general corrosion pattern during the dissolution of such alloy, and the cavities (pits) appearing on the alloy surface are larger and deeper. As the indium content is increased from 0.02% to 0.05%, the Al-Zn-In alloy potential decreases by about 50 mV to -1100 mV vs. Ag/AgCl electrode, which is advantageous in terms of using this alloy as a sacrificial anode. When the indium content is further increased from 0.05% to 0.2%, the potential of the alloy is no longer changed to a more negative one. The results obtained from all these tests demonstrate that alloys containing up to 0.05% of In additive are practically applicable for cathodic protection.

16.
AANA J ; 89(1): 27-33, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33501906

RESUMO

Volatile anesthetic agents act as greenhouse gases. Low-flow anesthesia techniques (≤1 L/min) are associated with lower costs. Decreasing volatile anesthetic delivery provides safe and effective strategies for anesthesia providers to decrease costs and reduce environmental pollution. This evidence-based project aimed to estimate cost savings and reduction in the environmental release of anesthetic gases, under simulated lower fresh gas flow (FGF) practices. For each surgical case, the exhaled anesthetic gas percent and FGF data were used to calculate the volume of fluid volatile anesthetic. The fluid volatile anesthetic for each case was then estimated using simulated FGFs. Changes in volatile agent cost and environmental release of anesthetic gases were predicted. Sevoflurane was the most commonly used volatile agent. The mean FGF for cases using sevoflurane was 2.5 L/min. The simulated FGF of 1 L/min FGF across all agents predicted a 48% ($50,892) reduction in costs of volatile anesthetics and a 42% (33 metric tons of carbon dioxide equivalent) decrease in carbon emissions. Simulated low-flow anesthesia demonstrated cost savings and environmental conservation. Project findings align with current literature showing that lowering FGFs represents an area of cost containment and an opportunity to lessen the environmental impact of anesthesia.


Assuntos
Anestesia por Inalação , Anestésicos Inalatórios , Dióxido de Carbono , Redução de Custos , Humanos , Sevoflurano
17.
Undersea Hyperb Med ; 47(3): 467-470, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32931674

RESUMO

Middle ear barotrauma due to dilatory Eustachian tube dysfunction (ETD) is probably the most common medical disorder related to diving. Moreover, ETD makes divers prone to other diving-related accidents, including inner ear barotrauma and alternobaric vertigo. Until the development of Eustachian tube balloon dilation no diving-compatible surgical options existed to effectively and safely prevent recurrence. We present a case of an Israeli Navy SEAL diver who dives in extreme strenuous combat-related closed-circuit rebreather (CCR) dives. Due to repeated middle ear barotrauma, the patient underwent Eustachian tube balloon dilation of the affected side. Following surgery, the patient returned to both CCR and scuba dives but still suffered from middle ear symptoms and repeated barotrauma hence was eventually disqualified from further combat diving.


Assuntos
Barotrauma/cirurgia , Dilatação/métodos , Mergulho/lesões , Tuba Auditiva/lesões , Tuba Auditiva/cirurgia , Militares , Barotrauma/etiologia , Mergulho/efeitos adversos , Desenho de Equipamento , Tuba Auditiva/fisiologia , Humanos , Masculino , Recidiva , Retorno ao Trabalho , Manobra de Valsalva/fisiologia , Adulto Jovem
18.
J Fish Biol ; 97(4): 1143-1153, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32743800

RESUMO

Saint Peter and Saint Paul's Archipelago (SPSPA), one of the smallest and most isolated island groups in the world, is situated on the Mid-Atlantic Ridge, between Brazil and the African continent. SPSPA has low species richness and high endemism; nonetheless, the diversity of fishes from deep habitats (>30 m depth) had not been previously studied in detail. Several expeditions conducted between 2009 and 2018 explored the shallow and deep reefs of SPSPA using scuba, closed-circuit rebreathers, manned submersibles, baited remote underwater stereo-videos (stereo-BRUV) and fishing between 0 and 1050 m depth. These expeditions yielded 41 new records of fishes for SPSPA: 9 in open waters, 9 in shallow waters (0-30 m), 8 in mesophotic ecosystems (30-150 m) and 15 in deeper reefs (>150 m). Combined with literature records of adult pelagic, shallow and deep-reef species, as well as larvae, the database of the fish biodiversity for SPSPA currently comprises 225 species (169 recorded as adult fishes and 79 as larvae, with 23 species found in both stages). Most of them (112) are pelagic, 86 are reef-associated species and 27 are deep-water specialists. Species accumulation curves show that the number of fish species has not yet reached an asymptote. Whereas the number of species recorded in SPSPA is similar to that in other oceanic islands in the Atlantic Ocean, the proportion of shorefishes is relatively lower, and the endemism level is the third highest in the Atlantic. Twenty-nine species are listed as threatened with extinction. Observations confirm the paucity of top predators on shallow rocky reefs of the island, despite the presence of several pelagic shark species around SPSPA. Because all of the endemic species are reef associated, it is argued that the new marine-protected areas created by the Brazilian government do not ensure the protection and recovery of SPSPA's biodiversity because they allow exploitation of the most vulnerable species around the archipelago itself. This study suggests a ban on reef fish exploitation inside an area delimited by the 1000 m isobath around the islands (where all known endemics are concentrated) as the main conservation strategy to be included in the SPSPA management plan being prepared by the Brazilian government.


Assuntos
Biodiversidade , Bases de Dados Factuais , Peixes/classificação , Animais , Oceano Atlântico , Brasil , Recifes de Corais , Ecossistema , Ilhas , Tubarões
19.
Zookeys ; 941: 145-161, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32595413

RESUMO

Two new species of Plectranthias perchlets are described, collected from mesophotic coral ecosystems in French Polynesia and the Republic of the Marshall Islands, in the tropical Central Pacific. Plectranthias polygonius sp. nov. was collected at a depth of 105 m in Tahiti, French Polynesia, and 120 m in Maloelap Atoll, Republic of the Marshall Islands. It was also observed in Moorea and Rangiroa (French Polynesia), and at Majuro and Erikub Atolls, Republic of the Marshall Islands. Plectranthias hinano sp. nov. was collected at a depth of 90-98 m in Tahiti, French Polynesia, and observed in Moorea. The barcode fragment of the cytochrome oxidase I gene of Plectranthias polygonius sp. nov. does not closely match any published sequence of Plectranthias, with approximately 15% uncorrected divergence from several species. Plectranthias polygonius sp. nov. can be distinguished from all of its congeners by coloration and morphology. The barcode fragment of the COI gene of Plectranthias hinano sp. nov. is closest to Plectranthias bennetti, with 5.4% uncorrected divergence. Plectranthias hinano sp. nov. is also distinguished from all of its congeners by morphology, and a coloration that includes two indistinct black spots along the base of the dorsal-fin, and transparent yellow dorsal and anal fin membranes. With this publication, the genus Plectranthias now comprises 58 valid species, with representatives from tropical to temperate waters of the Atlantic, Pacific, and Indian oceans. These two new discoveries add to the growing body of research highlighting the rich biodiversity of mesophotic ecosystems.

20.
J Forensic Sci ; 65(4): 1155-1168, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32134510

RESUMO

As the closed-circuit television (CCTV) security industry transitioned from analog media to digital video recorders (DVRs) with digital storage, the law enforcement community struggled with the means with which to collect the recordings. New guidelines needed to be established to determine the collection method which would be efficient as well as provide the best quality evidence from live DVRs. A test design was developed to measure, quantify, and rank the quality of acquisition methods used on live systems from DVRs typically used in digital CCTV systems. The purpose was to determine guidelines for acquiring the best quality video for investigative purposes. A test pattern which provided multiple quantifiable metrics for comparison between the methods of acquisition was used. The methods of acquisition included direct data download of the proprietary file and open file format as well as recording the video playback from the DVR via the available display monitor connections including the composite video, Video Graphics Array (VGA), and high-definition multimedia interface (HDMI). While some acquisition methods may provide the best quality evidence, other methods of acquisition are not to be discounted depending on the situation and need for efficiency. As an investigator that needs to retrieve video evidence from live digital CCTV systems, the proprietary file format, overall, provides the best quality evidence. However, depending on the circumstance and as recording technology continues to evolve, options other than the proprietary file format may provide quality that is equal to or greater than the proprietary file format.

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