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Background: Heart failure (HF) is a global health burden, and its management in the emergency department (ED) is important. This study aimed to evaluate the association between focused cardiac ultrasound (FoCUS) and early administration of diuretics in patients with acute HF admitted to the ED.Methods: This retrospective observational study was conducted at a tertiary academic hospital. Patients with acute HF patients who were admitted to the ED and receiving intravenous medication between January 2018 and December 2019 were enrolled. The main exposure was a FoCUS examination performed within 2 h of ED triage. The primary outcome was the time to furosemide administration.Results: Of 1154 patients with acute HF, 787 were included in the study, with 116 of them having undergone FoCUS. The time to furosemide was significantly shorter in the FoCUS group (median time (q1-q3), 112 min; range, 65-163 min) compared to the non-FoCUS group (median time, 131 min; range, 71-229 min). In the multivariable logistic regression analysis adjusting for age, sex, chief complaint, mode of arrival, triage level, shock status, and desaturation at triage, early administration of furosemide within 2 h from triage was significantly higher in the FoCUS group (adjusted odds ratio, 1.63; 95% confidence intervals, 1.04-2.55) than in the non-FoCUS group.Conclusions: Early administration of intravenous furosemide was associated with FoCUS examination in patients with acute HF admitted to the ED. An early screening protocol could be useful for improving levels in clinical practice at EDs. [ABSTRACT FROM AUTHOR]

Ticks inject serine protease inhibitors (serpins) into their feeding sites to evade serine protease-mediated host defenses against tick-feeding. This study describes two highly identitical (97%) but functionally different Amblyomma americanum tick saliva serpins (AAS41 and 46) that are secreted at the inception of tick-feeding. We show that AAS41, which encodes a leucine at the P1 site inhibits inflammation system proteases: chymase (SI = 3.23, Ka = 5.6 ± 3.7X103M−1 s−1) and α-chymotrypsin (SI = 3.18, Ka = 1.6 ± 4.1X104M−1 s−1), while AAS46, which encodes threonine has no inhibitory activity. Similary, rAAS41 inhibits rMCP-1 purified from rat peritonuem derived mast cells. Consistently, rAAS41 inhibits chymase-mediated inflammation induced by compound 48/80 in rat paw edema and vascular permeability models. Native AAS41/46 proteins are among tick saliva immunogens that provoke anti-tick immunity in repeatedly infested animals as revealed by specific reactivity with tick immune sera. Of significance, native AAS41/46 play critical tick-feeding functions in that RNAi-mediated silencing caused ticks to ingest significantly less blood. Importantly, monospecific antibodies to rAAS41 blocked inhibitory functions of rAAS41, suggesting potential for design of vaccine antigens that provokes immunity to neutralize functions of this protein at the tick-feeding site. We discuss our findings with reference to tick-feeding physiology and discovery of effective tick vaccine antigens. • Amblyomma americanum secretes two highly identical (97% identity) serpins (AAS 41 and 46) that have different functions • Amblyomma americanum utilizes AAS41 to block host inflammation defense by disrupting chymase and chymotrypsin functions • Functions of AAS 41 and 46 are critical to tick feeding success as revealed by RNAi mediated silencing • Both AAS 41 and 46 are among immunogens that provoke anti-tick immunity in repeatedly infested rabbits. [ABSTRACT FROM AUTHOR]

Studies on the transcriptional control of gene expression are crucial to understand changes in organism's physiological or cellular conditions. To obtain reliable data on mRNA amounts and the estimation of gene expression levels, it is crucial to normalize the target gene with one or more internal reference gene(s). However, the use of constitutive genes as reference genes is controversial, as their expression patterns are sometimes more complex than previously thought. In various arthropod vectors, including ticks, several constitutive genes have been identified by studying gene expression in different tissues and life stages. The cattle tick Rhipicephalus microplus is a major vector for several pathogens and is widely distributed in tropical and subtropical regions globally. Tick developmental physiology is an essential aspect of research, particularly embryogenesis, where many important developmental events occur, thus the identification of stable reference genes is essential for the interpretation of reliable gene expression data. This study aimed to identify and select R. microplus housekeeping genes and evaluate their stability during embryogenesis. Reference genes used as internal control in molecular assays were selected based on previous studies. These genes were screened by quantitative PCR (qPCR) and tested for gene expression stability during embryogenesis. Results demonstrated that the relative stability of reference genes varied at different time points during the embryogenesis. The GeNorm tool showed that elongation factor 1α (Elf1a) and ribosomal protein L4 (Rpl4) were the most stable genes, while H3 histone family 3A (Hist3A) and ribosomal protein S18 (RpS18) were the least stable. The NormFinder tool showed that Rpl4 was the most stable gene, while the ranking of Elf1a was intermediate in all tested conditions. The BestKeeper tool showed that Rpl4 and cyclophilin A (CycA) were the more and less stable genes, respectively. These data collectively demonstrate that Rpl4, Elf1a , and GAPDH are suitable internal controls for normalizing qPCR during R. microplus embryogenesis. These genes were consistently identified as the most stable in various analysis methods employed in this study. Thus, findings presented in this study offer valuable information for the study of gene expression during embryogenesis in R. microplus. [ABSTRACT FROM AUTHOR]

The adaptation of hard ticks to feed for long periods is facilitated by the cement cone, which securely anchors the tick mouthparts onto host skin and protects the tick from being groomed off by the host. Thus, preventing tick cement deposition is an attractive target for the development of innovative tick control. We used LC-MS/MS sequencing to identify 160 Amblyomma americanum tick cement proteins that include glycine-rich proteins (GRP, 19%), protease inhibitors (12%), proteins of unknown function (11%), mucin (4%), detoxification, storage, and lipocalin at 1% each, and housekeeping proteins (50%). Spatiotemporal transcription analysis showing mRNA expression in multiple tick organs and transcript abundance increasing with feeding suggest that selected GRPs ( n  = 13) regulate multiple tick feeding functions, being classified as constitutively expressed (CE), feeding induced (FI), and up-regulated with feeding (UR). We show that transcription of CE GRPs is likely under the control of tick appetence associated factors in that mRNA abundance increased several thousand fold in 1 week old adult ticks, the time period that coincides with tick attainment of appetence. Given the high number of targets, we synthesized and injected unfed ticks with combinatorial (co) double stranded (ds)RNA and disrupted GRP mRNA in clusters according to similar transcription patterns: CE ( n  = 3), FI, ( n  = 4), and UR ( n  = 6) to streamline the work. Our data suggest that CE and FI GRPs are important for maintenance of the tick feeding site in that reddening and subsequent bleeding were observed around the mouthparts of CE and FI GRP co-dsRNA injected ticks during feeding. Furthermore, although not significantly different, indices for blood meal size and fecundity were apparently reduced in FI and UR ticks. We discuss our data with reference to A. americanum tick feeding physiology. [ABSTRACT FROM AUTHOR]

Serine p rotease inhibitors (serpins) are thought to mediate the tick’s evasion of the host’s serine protease-mediated defense pathways such as inflammation and blood clotting. This study describes characterization and target validation of 11 blood meal-responsive serpins that are associated with nymph and adult Ixodes scapularis tick feeding as revealed by quantitative (q)RT-PCR and RNAi silencing analyses. Given the high number of targets, we used combinatorial (co) RNAi silencing to disrupt candidate serpins in two groups (G): seven highly identical and four non-identical serpins based on amino acid identities, here after called GI and GII respectively. We show that injection of both GI and GII co-dsRNA into unfed nymph and adult I. scapularis ticks triggered suppression of cognate serpin mRNA. We show that disruption of GII, but not GI serpins significantly reduced feeding efficiency of both nymph and adult I. scapularis ticks. Knockdown of GII serpin transcripts caused significant respective mortalities of ≤40 and 71% of nymphal and adult ticks that occurred within 24–48 h of attachment. This is significant, as the observed lethality preceded the tick feeding period when transmission of tick borne pathogens is predominant. We suspect that some of the GII serpins (S9, S17, S19 and S32) play roles in the tick detachment process in that upon detachment, mouthparts of GII co-dsRNA injected were covered with a whitish gel-like tissue that could be the tick cement cone. Normally, ticks do not retain tissue on their mouthparts upon detachment. Furthermore, disruption of GII serpins reduced tick blood meal sizes and the adult tick’s ability to convert the blood meal to eggs. We discuss our data with reference to tick feeding physiology and conclude that some of the GII serpins are potential targets for anti-tick vaccine development. [ABSTRACT FROM AUTHOR]

Inflammation and hemostasis are part of the host's first line of defense to tick feeding. These systems are in part serine protease mediated and are tightly controlled by their endogenous inhibitors, in the serpin superfamily (serine protease inhibitors). From this perspective ticks are thought to use serpins to evade host defenses during feeding. The cattle tick Rhipicephalus microplus encodes at least 24 serpins, of which RmS-3, RmS-6, and RmS-17 were previously identified in saliva of this tick. In this study, we screened inhibitor functions of these three saliva serpins against a panel of 16 proteases across the mammalian defense pathway. Our data confirm that Pichia pastoris -expressed rRmS-3, rRmS-6, and rRmS-17 are likely inhibitors of pro-inflammatory and pro-coagulant proteases. We show that rRmS-3 inhibited chymotrypsin and cathepsin G with stoichiometry of inhibition (SI) indices of 1.8 and 2.0, and pancreatic elastase with SI higher than 10. Likewise, rRmS-6 inhibited trypsin with SI of 2.6, chymotrypsin, factor Xa, factor XIa, and plasmin with SI higher than 10, while rRmS-17 inhibited trypsin, cathepsin G, chymotrypsin, plasmin, and factor XIa with SI of 1.6, 2.6, 2.7, 3.4, and 9.0, respectively. Additionally, we observed the formation of irreversible complexes between rRmS-3 and chymotrypsin, rRmS-6/rRmS-17 and trypsin, and rRmS-3/rRmS-17 and cathepsin G, which is consistent with typical mechanism of inhibitory serpins. In blood clotting assays, rRmS-17 delayed plasma clotting by 60 s in recalcification time assay, while rRmS-3 and rRmS-6 did not have any effect. Consistent with inhibitor function profiling data, 2.0 μM rRmS-3 and rRmS-17 inhibited cathepsin G-activated platelet aggregation in a dose-responsive manner by up to 96% and 95% respectively. Of significant interest, polyclonal antibodies blocked inhibitory functions of the three serpins. Also notable, antibodies to Amblyomma americanum , Ixodes scapularis , and Rhipicephalus sanguineus tick saliva proteins cross-reacted with the three R. microplus saliva serpins, suggesting the potential of these proteins as candidates for universal anti-tick vaccines. [ABSTRACT FROM AUTHOR]

Tick saliva serine protease inhibitors (serpins) facilitate tick blood meal feeding through inhibition of protease mediators of host defense pathways. We previously identified a highly conserved Amblyomma americanum serpin 19 that is characterised by its reactive center loop being 100% conserved in ixodid ticks. In this study, biochemical characterisation reveals that the ubiquitously transcribed A. americanum serpin 19 is an anti-coagulant protein, inhibiting the activity of five of the eight serine protease blood clotting factors. Pichia pastoris -expressed recombinant (r) A. americanum serpin 19 inhibits the enzyme activity of trypsin, plasmin and blood clotting factors (f) Xa and XIa, with stoichiometry of inhibition estimated at 5.1, 9.4, 23.8 and 28, respectively. Similar to typical inhibitory serpins, recombinant A. americanum serpin 19 forms irreversible complexes with trypsin, fXa and fXIa. At a higher molar excess of recombinant A. americanum serpin 19, fXIIa is inhibited by 82.5%, and thrombin (fIIa), fIXa, chymotrypsin and tryptase are inhibited moderately by 14–29%. In anti-hemostatic functional assays, recombinant A. americanum serpin 19 inhibits thrombin but not ADP and cathepsin G activated platelet aggregation, delays clotting in recalcification and thrombin time assays by up to 250 s, and up to 40 s in the activated partial thromboplastin time assay. Given A. americanum serpin 19 high cross-tick species conservation, and specific reactivity of recombinant A. americanum serpin 19 with antibodies to A. americanum tick saliva proteins, we conclude that recombinant A. americanum serpin 19 is a potential candidate for development of a universal tick vaccine. [ABSTRACT FROM AUTHOR]

In this study we characterized Amblyomma americanum ( Aam ) tick calreticulin (CRT) homolog in tick feeding physiology. In nature, different tick species can be found feeding on the same animal host. This suggests that different tick species found feeding on the same host can modulate the same host anti-tick defense pathways to successfully feed. From this perspective it's plausible that different tick species can utilize universally conserved proteins such as CRT to regulate and facilitate feeding. CRT is a multi-functional protein found in most taxa that is injected into the vertebrate host during tick feeding. Apart from it's current use as a biomarker for human tick bites, role(s) of this protein in tick feeding physiology have not been elucidated. Here we show that annotated functional CRT amino acid motifs are well conserved in tick CRT. However our data show that despite high amino acid identity levels to functionally characterized CRT homologs in other organisms, Aam CRT is apparently functionally different. Pichia pastoris expressed recombinant (r) Aam CRT bound C1q, the first component of the classical complement system, but it did not inhibit activation of this pathway. This contrast with reports of other parasite CRT that inhibited activation of the classical complement pathway through sequestration of C1q. Furthermore r Aam CRT did not bind factor Xa in contrast to reports of parasite CRT binding factor Xa, an important protease in the blood clotting system. Consistent with this observation, r Aam CRT did not affect plasma clotting or platelet aggregation. We discuss our findings in the context of tick feeding physiology. [ABSTRACT FROM AUTHOR]

Abstract: Important role of chemical interaction in flame extinction is numerically investigated in downstream interaction among lean (rich) and lean (rich) premixed as well as partially premixed H2- and CO-air flames. The strain rate varies from 30 to 5917 s−1 until interacting flames cannot be sustained anymore. Flame stability diagrams mapping lower and upper limit fuel concentrations for flame extinction as a function of strain rate are presented. Highly stretched interacting flames are survived only within two islands in the flame stability map where partially premixed mixture consists of rich H2-air flame, extremely lean CO-air flame, and a diffusion flame. Further increase in strain rate finally converges to two points. It is found that hydrogen penetrated from H2-air flame (even at lean flame condition) participates in CO oxidation vigorously due to the high diffusivity such that it modifies the slow main reaction route CO + O2 → CO2 + O into the fast cyclic reaction route involving CO + OH → CO2 + H. These chemical interactions force even rich extinction boundaries with deficient reactant Lewis numbers larger than unity to be slanted at high strain rate. Appreciable amount of hydrogen in the side of lean H2-air flame also oxidizes the CO penetrated from CO-air flame, and this reduces flame speed of the H2-air flame, leading to flame extinction. At extremely high strain rates, interacting flames are survived only by a partially premixed flame such that it consists of a very rich H2-air flame, an extremely lean CO-air flame, and a diffusion flame. In such a situation, both the weaker H2- and CO-air flames are parasite on the stronger diffusion flame such that it can lead to flame extinction in the situation of weakening the stronger diffusion flame. Important role of chemical interaction in flame extinction is discussed in detail. [Copyright &y& Elsevier]

Abstract: We previously identified a cross-tick species conserved tick feeding stimuli responsive Amblyomma americanum (Aam) AV422 gene. This study demonstrates that AamAV422 belongs to a novel group of arthropod proteins that is characterized by 14 cysteine amino acid residues: C23-X7/9-C33–X23/24-C58-X8-C67-X7-C75-X23-C99-X15-C115-X10-C126-X24/25/33-C150C151-X7-C159-X8-C168-X23/24-C192-X9/10-C202 predicted to form seven disulfide bonds. We show that AamAV422 protein is a ubiquitously expressed protein that is injected into the host within the first 24h of the tick attaching onto the host as revealed by Western blotting analyses of recombinant (r)AamAV422, tick saliva and dissected tick organ protein extracts using antibodies to 24 and 48h tick saliva proteins. Native AamAV422 is apparently involved with mediating tick anti-hemostasis and anti-complement functions in that rAamAV422 delayed plasma clotting time in a dose responsive manner by up to ∼160s, prevented platelet aggregation by up to ∼16% and caused ∼24% reduction in production of terminal complement complexes. Target validation analysis revealed that rAamAV422 is a potential candidate for a cocktail or multivalent tick vaccine preparation in that RNA interference (RNAi)-mediated silencing of AamAV422 mRNA caused a statistically significant (∼44%) reduction in tick engorgement weights, which is proxy for amounts of ingested blood. We speculate that AamAV422 is a potential target antigen for development of the highly desired universal tick vaccine in that consistent with high conservation among ticks, antibodies to 24h Ixodes scapularis tick saliva proteins specifically bound rAamAV422. We discuss data in this study in the context of advancing the biology of tick feeding physiology and discovery of potential target antigens for tick vaccine development. [Copyright &y& Elsevier]

A visualization study on the effect of forcing amplitude in tone-excited jet diffusion flames has been conducted. Visualization techniques are employed using optical schemes, which are a light scattering photography. Flame stability curve is attained according to Reynolds number and forcing amplitude at a fuel tube resonant frequency. Flame behavior is globally grouped into two from attached flame to blown-out flame according to forcing amplitude; one sticks the tradition flame behavior which has been observed in general jet diffusion flames and the other shows a variety of flame modes such as the flame of a feeble forcing amplitude where traditionally well-organized vortex motion evolves, a fat flame, an elongated flame, and an in-burning flame. Particular attention is focused on an elongation flame, which is associated with a turnabout phenomenon of vortex motion, and on a reversal of the direction of vortex roll-up. It is found that the flame length with forcing amplitude is the direct outcome of the evolution process of the formed inner flow structure. Especially the negative part of the acoustic cycle under the influence of a strong positive pressure gradient causes the shapes of the fuel stem and fuel branch part and even the direction of vortex roll-up to dramatically change. [Copyright &y& Elsevier]

Cyclodextrin (CD), a doughnut-shaped molecule having a hydrophilic surface and hydrophobic interior, can form inclusion complexes with various hydrophobic guest molecules inducing them into the emulsion state. The CD-induced emulsion reaction system was applied to the esterification between the hydrophobic oleic acid as the carboxylic acid and n-butanol as the alcohol catalyzed by lipase. The rate and yield were substantially increased in the CD-induced emulsion reaction system. The optimal reaction condition and the kinetic constants of the esterification reaction were determined. The enhancing mechanism was investigated through comparing the microscopic observation of the reaction mixtures, the inclusion complex formability, and the distribution of substrates, product and lipase at aqueous phase and CD-induced water immiscible phase in the CD-induced emulsion reaction system. The increase seems to have been caused by three reasons, the increased accessibility of lipase due to the emulsion formation, the shift of the equilibrium to the product formation side through the decrement of the affinity of butyl oleate with lipase, and the activation of lipase adsorbed on interface of oil-droplets in CD-induced water immiscible phase. [Copyright &y& Elsevier]

Abstract: Numerical study on the interaction between methane–air and syngas–air premixed flames is conducted according to equivalence ratio and global strain rate in detailed chemistry. This study targets at understanding of an interacting combustion system as an alternative retrofit concept where one can modify the existing facilities minimally in industrial and power plant burners in order to reduce the emission of carbon dioxide. It is seen that methane premixed flame interacting with syngas premixed flame can be sustained even over the rich flammable limit of single methane premixed flame. The inspection of detailed flame structure such as the distributions of major species and chain carrier radicals, flame separation distance, spatial flow velocity, and spatial distribution of the rate of production and consumption of CH4, H2, and CO is also conducted to depict the flame interactions. The importance of global strain rate and thus the flame separation distance in the enhanced burning of methane premixed flame is also stressed through the inspection of the consumption rates of H2, CO, and CH4. Anomalous phenomena such as the migration of premixed flame cross the stagnation plane and the nearly constant flame separation distance are also discussed. [Copyright &y& Elsevier]

Abstract: Numerical study is conducted to understand the impact of fuel composition and flame radiation in flame structure and their oxidation process in H2/CO synthetic gas diffusion flame with and without CO2 dilution. The models of Sun et al. and David et al., which have been well known to be best-fitted for H2/CO synthetic mixture flames, are evaluated for H2/CO synthetic mixture flames diluted with CO2. Effects of radiative heat loss to flame characteristics are also examined in terms of syngas mixture composition. Importantly contributing reaction steps to heat release rate are compared for the synthetic gas mixture flames of high contents of H2 and CO, individually, with and without CO2 dilution. The modification of the oxidation pathways is also addressed. [Copyright &y& Elsevier]

Abstract: Experiments in low-strain-rate methane–air counterflow diffusion flames diluted with nitrogen have been conducted to study flame extinction behavior and edge flame oscillation in which flame length is less than the burner diameter and thus lateral conductive heat loss, in addition to radiative loss, could be high at low global strain rates. The critical mole fraction at flame extinction is examined in terms of velocity ratio and global strain rate. Onset conditions of the edge flame oscillation and the relevant modes are also provided with global strain rate and nitrogen mole fraction in the fuel stream or in terms of fuel Lewis number. It is observed that flame length is intimately relevant to lateral heat loss, and this affects flame extinction and edge flame oscillation considerably. Lateral heat loss causes flame oscillation even at fuel Lewis number less than unity. Edge flame oscillations, which result from the advancing and retreating edge flame motion of the outer flame edge of low-strain-rate flames, are categorized into three modes: a growing, a decaying, and a harmonic-oscillation mode. A flame stability map based on the flame oscillation modes is also provided for low-strain-rate flames. The important contribution of lateral heat loss even to edge flame oscillation is clarified finally. [Copyright &y& Elsevier]