Initial Slow Phase Research Articles

Detection of spontaneous breathing during an apnea test in a patient with suspected brain death using electrical impedance tomography: a case report

IntroductionThe apnea test (AT) is a crucial procedure in determining brain death (BD), with detection of spontaneous breathing efforts serving as a key criterion. Numerous national statutes mandate complete disconnection of the patient from the ventilator during the procedure to open the airway directly to the atmosphere. These regulations mandate visual observation as an exclusive option for detecting breathing efforts. However, reliance on visual observation alone can pose challenges in identifying subtle respiratory movements.Case PresentationThis case report presents a 55-year-old morbidly obese male patient with suspected BD due to cerebral hemorrhage undergoing an AT. The AT was performed with continuous electrical impedance tomography (EIT) monitoring. Upon detection of spontaneous breathing movements by both visual observation and EIT, the AT was aborted, and the patient was reconnected to the ventilator. EIT indicated a shift in ventilation distribution from the ventral to the dorsal regions, indicating the presence of spontaneous breathing efforts. EIT results also suggested the patient experienced a slow but transient initial recovery phase, likely due to atelectasis induced by morbid obesity, before returning to a steady state of ventilatory support.ConclusionThe findings suggest EIT could enhance the sensitivity and accuracy of detecting spontaneous breathing efforts, providing additional insights into the respiratory status of patients during the AT.

Deciphering the Novel Picolinate-Mn(II)/peroxymonosulfate System for Sustainable Fenton-like Oxidation: Dominance of the Picolinate-Mn(IV)-peroxymonosulfate Complex.

A highly efficient and sustainable water treatment system was developed herein by combining Mn(II), peroxymonosulfate (PMS), and biodegradable picolinic acid (PICA). The micropollutant elimination process underwent two phases: an initial slow degradation phase (0-10 min) followed by a rapid phase (10-20 min). Multiple evidence demonstrated that a PICA-Mn(IV) complex (PICA-Mn(IV)*) was generated, acting as a conductive bridge facilitating the electron transfer between PMS and micropollutants. Quantum chemical calculations revealed that PMS readily oxidized the PICA-Mn(II)* to PICA-Mn(IV)*. This intermediate then complexed with PMS to produce PICA-Mn(IV)-PMS*, elongating the O-O bond of PMS and increasing its oxidation capacity. The primary transformation mechanisms of typical micropollutants mediated by PICA-Mn(IV)-PMS* include oxidation, ring-opening, bond cleavage, and epoxidation reactions. The toxicity assessment results showed that most products were less toxic than the parent compounds. Moreover, the Mn(II)/PICA/PMS system showed resilience to water matrices and high efficiency in real water environments. Notably, PICA-Mn(IV)* exhibited greater stability and a longer lifespan than traditional reactive oxygen species, enabling repeated utilization. Overall, this study developed an innovative, sustainable, and selective oxidation system, i.e., Mn(II)/PICA/PMS, for rapid water decontamination, highlighting the critical role of in situ generated Mn(IV).

Novel Peripheral Perfusion Dynamics Indices for Detecting and Grading Arterial Stenosis.

Peripheral artery disease causes severe morbidity, especially in diabetics and the elderly. There is a need for accurate noninvasive detection of peripheral arterial stenosis. The study has tested the hypothesis that arterial stenosis and the associated adaptation of the downstream circulation yield characteristic changes in the leg perfusion dynamics that enable early diagnosis, utilizing impedance plethysmography. The arterial perfusion dynamic was derived from impedance plethysmography (IPG). Two degrees of arterial stenosis were emulated by inflating a blood-pressure cuff around the thigh to 45 and 90mmHg, in healthy volunteers (n = 30). IPG signals were acquired continuously throughout the experiment. Ankle and brachial blood pressures were measured at the beginning of each experiment and at the end of each emulated stenosis phase. Thigh compressions did not affect the pulse-transit time, but prolonged the time to the peak perfusion wave. Segmentation of the perfusion upstroke into two phases, at the time point of maximum acceleration (MAT), revealed that arterial compression prolonged only the initial slow phase duration (SPd). The MAT and SPd were proportional to the emulated stenosis severity and detected the arterial stenosis with high sensitivity (>93%) and specificity (100%). The SPd increased from 46.4 ± 21.2ms at baseline to 75.4 ± 38.5ms and 145 ± 39ms under 45mmHg and 90mmHg compressions (p < 0.001), without affecting the pulse-transit time. The novel method and indices can identify and grade the emulated arterial stenosis with high accuracy and may assist in differentiating between focal arterial stenosis and widespread arterial hardening.

Autocatalytic Mechanism in the Anaerobic Reduction of Metmyoglobin by Sulfide Species.

The mechanism of the metal centered reduction of metmyoglobin (MbFeIII) by sulfide species (H2S/HS-) under an argon atmosphere has been studied by a combination of spectroscopic, kinetic, and computational methods. Asymmetric S-shaped time-traces for the formation of MbFeII at varying ratios of excess sulfide were observed at pH 5.3 < pH < 8.0 and 25 °C, suggesting an autocatalytic reaction mechanism. An increased rate at more alkaline pHs points to HS- as relevant reactive species for the reduction. The formation of the sulfanyl radical (HS•) in the slow initial phase was assessed using the spin-trap phenyl N-tert-butyl nitrone. This radical initiates the formation of S-S reactive species as disulfanuidyl/ disulfanudi-idyl radical anions and disulfide (HSSH•-/HSS•2- and HSS-, respectively). The autocatalysis has been ascribed to HSS-, formed after HSSH•-/HSS•2- disproportionation, which behaves as a fast reductant toward the intermediate complex MbFeIII(HS-). We propose a reaction mechanism for the sulfide-mediated reduction of metmyoglobin where only ferric heme iron initiates the oxidation of sulfide species. Beside the chemical interest, this insight into the MbFeIII/sulfide reaction under an argon atmosphere is relevant for the interpretation of biochemical aspects of ectopic myoglobins found on hypoxic tissues toward reactive sulfur species.

The β-myosin G256E mutation impairs relaxation by altering transducer stiffness.

Associations between mutations in sarcomeric proteins and familial cardiomyopathies are myriad. However, detailed structural and functional studies are required to describe the mechanistic relationship between a mutation and its pathology. To accelerate such studies, we utilize a combined computational and experimental platform to probe how mutations to b-myosin lead to familial cardiomyopathies. Here, we report results on the HCN-associated MYH7 mutation G256E, which is located in the myosin transducer. Experimentally, the specific force generation of mutant G256E myofibrils was ∼2x greater than isogenic control myofibrils. The activation rate was similarly increased. The initial slow phase relaxation kinetics of G256E myosin were significantly reduced relative to isogenic controls, indicating a slower cross-bridge detachment rate. Using stopped flow kinetics, the ATP binding rate was reduced in G256E relative to WT. Molecular dynamics simulations of the rigor and myosin.ATP states showed that G256E led to reorganization of hydrogen bonding networks within the transducer region. Enhanced sampling MD simulations modeled the rigor (nucleotide free) to post-rigor (ATP-bound) structural transition along multiple reaction coordinates. The transition required that G256E myosins surmount a greater energetic barrier that describes the binding of switch 1 to ATP, rotation of the transducer backbone, and opening of the actin binding cleft. This increased barrier is attributed to salt bridges formed by the mutant Glu residue. Based on our combined computational and experimental results, we hypothesize that G256E leads to a hypercontractile and delayed relaxation phenotype via modulation of the transducer structure. This alters communication between the nucleotide binding pocket and the actin binding surface during steps in the chemo-mechanical cycle that involve transducer motion during nucleotide release-induced strong actin binding and ATP binding-induced release from actin. Other effects on myosin structure and its activation during contraction are being investigated.

Modelling the effects of the pyrethroid insecticide cypermethrin on the life cycle of the soil dwelling annelid Enchytraeus crypticus, an original experimental design to calibrate a DEB-TKTD model

The Dynamic Energy Budget theory (DEB) enables ecotoxicologists to model the effects of chemical stressors on organism life cycles through the coupling of toxicokinetic-toxicodynamic (TK-TD) models. While good progress has been made in the application of DEB-TKTD models for aquatic organisms, applications for soil fauna are scarce, due to the lack of dedicated experimental designs suitable for collecting the required time series effect data. Enchytraeids (Annelida: Clitellata) are model organisms in soil ecology and ecotoxicology. They are recognised as indicators of biological activity in soil, and chemical stress in terrestrial ecosystems. Despite this, the application of DEB-TKTD models to investigate the impact of chemicals has not yet been tested on this family. Here we assessed the impact of the pyrethroid insecticide cypermethrin on the life cycle of Enchytraeus crypticus. We developed an original experimental design to collect the data required for the calibration of a DEB-TKTD model for this species. E. crypticus presented a slow initial growth phase that has been successfully simulated with the addition of a size-dependent food limitation for juveniles in the DEB model. The DEB-TKTD model simulations successfully agreed with the data for all endpoints and treatments over time. The highlighted physiological mode of action (pMoA) for cypermethrin was an increase of the growth energy cost. The threshold for effects on survival was estimated at 73.14 mg kg− 1, and the threshold for effects on energy budget (i.e., sublethal effects) at 19.21 mg kg− 1. This study demonstrates that DEB-TKTD models can be successfully applied to E. crypticus as a representative soil species, and may improve the ecological risk assessment for terrestrial ecosystems, and our mechanistic understanding of chemical effects on non-target species.

Regulable Mixed-Solvent-Induced Phase Separation in Hydrogels for Information Encryption.

The rapid progress of information technology is accompanied by plenty of information embezzlement and forgery, but developing advanced encryption technologies to ensure information security remains challenging. Phase separation commonly leads to a dramatic change in the transmittance of hydrophilic polymer networks, which is a potential method for information security but is often neglected. Here, taking the polyacrylamide (PAAm) hydrogel system as a typical example, facilely adjustable information encryption and decryption via its regulable phase separation process in ethanol/water mixed solvent, are reported. By controlling the osmotic pressure of the external and internal environment, it is demonstrated that the diffusion coefficient during deswelling and reswelling, as well as the corresponding change of transmittance of the gel, can be well controlled. Relatively high osmotic pressure leads to rapid phase separation of the initial gel but slow phase remixing of the phase-separated gel, opening the opportunity of applying the gel as a reversible information encryption device. As proof-of-concept demonstrations, several stable and reversible information encryption and decryption systems by making use of the phase separation process of the gels are designed, which are expected to inspire the development of next-generation soft devices for information technology.

Novel noninvasive indices of perfusion dynamics wave analysis detect above knee arterial stenosis in the presence of widespread arteriosclerosis

Abstract Introduction Peripheral arterial disease (PAD) is a leading cause of vascular morbidity and mortality. The Ankle Brachial Index (ABI) is a common index for screening and monitoring PAD. The AHA and ECS guidelines recommend measuring the ABI for assessing atherosclerotic cardiovascular risk. However, the ABI sensitivity is low, especially in the elderly and diabetics with arteriosclerosis. The restenosis rate after revascularization is high and there is an unmet need for continuous monitoring for detection of restenoses in these patients. ABI requires Doppler Ultrasound measurements. Purpose We hypothesized that monitoring the arterial perfusion dynamics instead of the peak systolic pressure, could improve PAD surveillance and management. Methods A novel method for quantifying the arterial perfusion dynamic from impedance plethysmography measurements was developed. A novel segmentation of the arterial perfusion upstroke has revealed that it consists of two characteristic phases, an initial slow phase that is followed by a fast vigorous rise. The phase transition point was defined by the maximum acceleration time point (MAT). The slow phase duration was denoted as the `Perfusion Deficit Index` (PDI). The arterial perfusion signals were derived from calves of PAD patients that were admitted for revascularization. We compared the novel PDI and MAT indices with measured ABI before and after the revascularizations. Results Sixteen patients with isolated above-knee stenoses were recruited and treated in eighteen legs. The perfusion signals before the revascularization were characterized by prolonged PDI, and overt shortening of the PDI was observed after successful revascularization, as depicted in Figure 1. The PDI was significantly negatively correlated with the ABI. In patients with satisfactory postoperative increase in ABI (&amp;gt;0.15) the PDI dropped from 105±33 ms to 26±16 ms (n=13, p&amp;lt;0.001). The “pulse transit time” (PTT) that relates to arteriosclerosis did not change between measurements in all the patients. Thus, the measurement of the PTT and PDI can differentiate between the two elements of atherosclerosis: generalized arteriosclerosis and development of localized arterial narrowing. Interestingly, in the contralateral untreated leg the ABI and PDI had a similar significantly negative correlation, without significant difference before and after the procedures. Assessment of the ABI and PDI abilities to detect focal stenosis revealed that the PDI detected stenosis with 91% sensitivity and 85% specificity, while the ABI only had 74% sensitivity and 85% specificity (Figure 2). Conclusions The PD can be used for assessing revascularization outcome and monitoring atherosclerosis severity. The MAT and PDI are novel sensitive and specific indices for detecting arterial stenoses, even in the presence of arteriosclerosis, unlike the ABI. The applicability of this simple to use method for screening and telemedicine should be further validated. Funding Acknowledgement Type of funding sources: None.

Analysis of cellular water content in T cells reveals a switch from slow metabolic water gain to rapid water influx prior to cell division

Cell growth is driven by the acquisition and synthesis of both dry biomass and water mass. In this study, we examine the increase of water mass in T cell during cell growth. We found that T-cell growth is characterized by an initial phase of slow increase in cellular water, followed by a second phase of rapid increase in water content. To study the origin of the water gain, we developed a novel methodology we call cold aqua trap-isotope ratio mass spectrometry, which allows analysis of the isotope composition of intracellular water. Applying cold aqua trap-isotope ratio mass spectrometry, we discovered that glycolysis-coupled metabolism of water accounts on average for 11 fl out of the 20 fl of water gained per cell during the initial slow phase. In addition, we show that at the end of the rapid phase before initiation of cell division, a water influx occurs, increasing the cellular water mass by threefold. Thus, we conclude that activated T cells switch from metabolizing water to rapidly taking up water from the extracellular medium prior to cell division. Our work provides a method to analyze cell water content as well as insights into the ways cells regulate their water mass.

Prominence instability and CMEs triggered by massive coronal rain in the solar atmosphere

Context. The triggering process for prominence instability and consequent coronal mass ejections (CMEs) is not fully understood. Prominences are maintained by the Lorentz force against the gravity; therefore, reduction of the prominence mass due to the coronal rain may cause the change of the force balance and hence destabilisation of the structures. Aims. We aim to study the observational evidence of the influence of coronal rain on the stability of prominence and subsequent eruption of CMEs. Methods. We used the simultaneous observations from the Atmospheric Imaging Assembly (AIA) of Solar Dynamics Observatory (SDO) and Sun Earth Connection Coronal and Heliospheric Investigation (SECHHI) of Solar Terrestrial Relations Observatory (STEREO) spacecrafts from different angles to follow the dynamics of prominence and to study the role of coronal rain in their destabilisation. Results. Three different prominences observed during the years 2011–2012 were analysed using observations acquired by SDO and STEREO. In all three cases, massive coronal rain from the prominence body led to the destabilisation of prominence and subsequently to the eruption of CMEs. The upward rising of prominences consisted of the slow and fast rise phases. The coronal rain triggered the initial slow rise of prominences, which led to the final instability (the fast rise phase) after 18–28 h in all cases. The estimated mass flux carried by coronal rain blobs showed that the prominences became unstable after 40% of mass loss. Conclusions. We suggest that the initial slow rise phase was triggered by the mass loss of prominence due to massive coronal rain, while the fast rise phase (the consequent instability of prominences) was caused by the torus instability and/or magnetic reconnection with the overlying coronal field. Therefore, the coronal rain triggered the instability of prominences and consequent CMEs. If this is the case, then the coronal rain can be used to predict the CMEs and hence to improve the space weather predictions.

Abstract 12155: Detecting Peripheral Arterial Stenosis and Monitoring Atherosclerosis Severity

Background: The AHA guidelines recommend measuring the Ankle-Brachial Index (ABI) for assessing the severity of atherosclerosis. There is also an unmet need for early detection of peripheral artery stenosis to reduce morbidity and tissue loss. However, the sensitivity of ABI in detecting arterial stenosis is limited in the presence of arterial stiffening (arteriosclerosis), especially in diabetic and elderly patients, since arteriosclerosis yields fictitious higher ABI. We hypothesize that non-invasive quantification of the peripheral perfusion dynamics, instead of a single pressure point, can improve the diagnosis and differentiate between focal stenosis and general arteriosclerosis. Methods: Impedance plethysmography (IPG) were measured from the calf of patients that underwent peripheral revascularization, before and shortly after the interventions. The characteristic perfusion dynamics curves were derived from the cardiac complexes of the IPG that were recorded over at least 3 minutes. Successful interventions were defined according to the guidelines as a post-operational ABI increase of at least 0.15. Results: Twenty-four patients (60.9±9.3 years old, 16 (66.6 %) diabetics) that underwent above-knee revascularization were analyzed. The perfusion upstroke consisted of two characteristic phases: an initial slow phase followed by a fast vigorous rise. Improvement in the perfusion after the revascularization appeared only in the initial slow duration, denoted as the ‘Perfusion Deficit Index` (PDI). Of those, 15 (62%) had a successful intervention and the PDI decreased from 115±48 ms to 22±10 ms (p&lt;0.0001) while the ABI increased from 0.53±0.26 to 0.94±0.22. In 9 limbs (37%) with unsuccessful interventions, there were no significant changes in PDI and ABI (from 143±31 ms to 117±40 ms and from 0.38±0.11 to 0.48±0.11, respectively). There was no significant change in the pulse transit time (p=0.19), a well-known index of arteriosclerosis, before and after the interventions. Conclusions: The PDI is a novel sensitive index for detection of focal arterial stenosis and it is independent of the severity of arteriosclerosis. This simple to use method can be used for monitoring atherosclerosis severity.

Estimation of Populuseuphratica Forest Leaf Litterfall and Time Variation of Nutrient in Leaf Litter during Decomposition along the Main Channel of the Tarim River, China

Accurate determination of annual leaf litter amount constitutes the basis of scientific leaf litter nutrient release assessment. In this study, we tried to establish an equation between leaf litter amount and relevant tree characteristics of Populus euphratica (P. euphratica) tree on an individual scale, and to find the leaf litter nutrient content variation within 760 d incubation experiment in the main channel of the Tarim River, China. Results showed that there was no proper equation between leaf litter amount and tree height or diameter at breast height. There was great difference in leaf litter amount on an individual scale. The mean annual leaf litter amount per tree was 10.2, 14.83 kg/y obtained by field survey and the equation between annual leaf litter amount and canopy area on an individual scale, respectively. Leaf litter mass changed over incubation time and exhibited three main phases: an initial slow decomposition phase (0–173 d) with mass loss; a rapid mass loss phase (173–290 d); and a second rapid mass loss phase (470–560 d). Overall, carbon (C) and potassium (K) content decreased, and nitrogen (N) and phosphorus (P) content increased in a fluctuating manner over time in the P. euphratica leaf litter.

Abstract 17377: Quantification of Arterial Stenosis Severity Based on the Changes in the Perfusion Wave Dynamics; a Novel Technology for Monitoring Peripheral Artery Disease

Introduction: Current screening modalities for peripheral artery disease (PAD) lack sensitivity especially in the elderly and diabetics, and there is an unmet need for early detection of restenosis after revascularization. Hypothesis: We have hypothesized that arterial stenosis is associated with adaptive arteriolar vasodilatation, which alters the downstream perfusion dynamics and prolongs the initial phase of the perfusion upstroke. These changes can be utilized for quantification of the arterial stenosis severity. Methods: We measured the lower leg perfusion with impedance plethysmography and compared it with other modalities used in the clinic and the gold-standard angiography. The various phases of the perfusion wave were identified by analyzing the first and second derivatives of the plethysmography. The signals were acquired from PAD patients before and after they underwent revascularization, to validate the ability to detect stenosis and successful revascularization. Results: Eighteen consenting patients were recruited (61±10 years old) and nineteen legs were treated. The perfusion upstroke encompasses 2 or 3 distinctive phases. An initial slow phase that is followed by a brisk upstroke and a final sallower augmentation in some patients. The slow phase duration (SPd) was 113±45 ms in extremities with above-knee (AK) arterial stenosis (n=17) while significantly shorter SPd of 26±0 ms was observed in limbs without AK stenoses (P = 0.011). In the AK extremities, the SPd significantly decreased to 52±40 ms after successful revascularization (P&lt;0.01). Moreover, in AK cases with a satisfactory post-operative result (Duplex assessment), the SPd dramatically decreased from 103±35 ms before revascularization to 35±18 ms afterward (P&lt;0.01, n=12). Conclusions: Analysis of the perfusion dynamic provides a gamut of precious indices. The SPd is a novel index that can detect and quantify the severity of arterial stenosis. The technology can significantly improve the surveillance of PAD patients and may be used for early detection of restenosis.

MULTIWAVELENGTH OBSERVATIONS OF MASTER OT 075353.88+174907.6: A LIKELY SUPEROUTBURST OF A LONG PERIOD DWARF NOVA SYSTEM

MASTER OT 075353.88+174907.6 was a blue optical transient reported by the MASTER-Net project on 2017 Oct 31. We carried out multiwavelength followup observations of this source during its 2017 outburst using Swift and RATIR. The source was found to be ∼&gt;4.4 mag above its quiescent level during the peak of the outburst and the outburst lasted ∼&gt;19 days. Our observations suggest that it was a superoutburst of a long period U Geminorum type dwarf nova system. The spectral energy distribution during the initial slow decay phase of the outburst was consistent with a disk-dominated spectrum (with spectral indices Γ≈1.5–2.3). Afterwards, the UV flux decreased slowlier than the optical and the spectral energy distribution was very steep with indices Γ≈3.7±0.7. This slow UV decay may be the emission from a cooling white dwarf heated during the outburst. No X-ray emission was detected from the source since it is likely located at a large distance &gt;2.3 kpc.

Breakup Without Borders: How Continents Speed Up and Slow Down During Rifting

AbstractRelative plate motions during continental rifting result from the interplay of local with far‐field forces. Here we study the dynamics of rifting and breakup using large‐scale numerical simulations of mantle convection with self‐consistent evolution of plate boundaries. We show that continental separation follows a characteristic evolution with four distinctive phases: (1) an initial slow rifting phase with low divergence velocities and maximum tensional stresses, (2) a synrift speed‐up phase featuring an abrupt increase of extension rate with a simultaneous drop of tensional stress, (3) the breakup phase with inception of fast sea‐floor spreading, and (4) a deceleration phase occurring in most but not all models where extensional velocities decrease. We find that the speed‐up during rifting is compensated by subduction acceleration or subduction initiation even in distant localities. Our study illustrates new links between local rift dynamics, plate motions, and subduction kinematics during times of continental separation.

Study on the Reoxidation Characteristics of Soaked and Air-Dried Coal

After coal seam mining, the residual coal is soaked with the accumulated water in goaf, and its spontaneous combustion characteristics were changed after air-dried. To study the reoxidation characteristics of soaked and air-dried coal, temperature-programmed experiments were carried out, and the cross point temperatures and index gases were investigated. Results showed that the cross point temperature of raw coal (146.3 °C) was reduced to 137.1 °C after it was pre-oxidized at 90 °C. The cross point temperature of water-soaked, and air-dried coal (96 h) was 122.5 °C, while the cross point temperature of water-soaked, air-dried (96 h) and pre-oxidized (90 °C) coal was 111.5 °C. Although CO was produced in the initial slow oxidation phase, it was found that C2H4 and C3H8 were not generated. In the rapid oxidation stage, different pretreatments affected the gas generation and the overall oxidative degree was consistent with the cross point temperature. The generation temperature and the concentration of C2H4 and C3H8 were decreased after the coal was water-soaked, air-dried, and pre-oxidized. Furthermore, the high-energy chemicals and functional groups were studied, which could be used to explain the physical experiment oxidation characteristics of different coals.

Phomopsidione nanoparticles coated contact lenses reduce microbial keratitis causing pathogens

Microbial keratitis is the infection caused by pathogenic microorganisms that commonly occurs among the contact lens users. Various antimicrobial compounds were coated on contact lenses to kill keratitis causing microorganisms, however these compounds caused several adverse side effects. Hence, the aim of this study is to develop a silicone hydrogel contact lens coated with phomopsidione nanoparticle that inhibit keratitis causing clinical isolates. Phomopsidione nanoparticles were synthesized using polyvinyl alcohol as encapsulant. The nanoparticles showed an average size of 77.45 nm, with neutral surface charge. Two drug release patterns were observed in the drug release profile, which are the initial slow release phase with extended drug release (release rate 46.65 μg/h), and the burst release phase observed on Day 2 (release rate 2224.49 μg/h). This well-regulated drug delivery system enables the control of drug release to meet the therapeutic requirements. On agar diffusion assay, 3 out of 5 test microorganisms were inhibited by phomopsidione nanoparticle coated contact lenses, including two Gram negative bacteria. Besides, all test microorganisms showed at least 99% of growth reduction, with the treatment of the contact lens model. The drug loaded onto the nanoparticles is sufficient to prevent the bacterial growth. In conclusion, this study provides an effective alternative to combat keratitis-causing microorganisms among contact wearers.

Kinetics and mechanism of oxidation of pyruvate by permanganate ion in aqueous perchlorate solution

The kinetics and mechanism of permanganate oxidation of pyruvic acid in aqueous perchlorate at a constant ionic strength of 2.0 mol dm−3 have been investigated spectrophotometrically. The pseudo-first-order plots showed two distinct phases for the reaction, characterized as induction and auto-acceleration periods. The induction phase is relatively slow at the early stages of reaction and is followed by a faster process. The rate law for the oxidation was described by the sum of two exponential terms. The oxidation showed overall second-order kinetics with respect to the reactants in the initial slow phase. However, second-order kinetics was not maintained throughout the faster second stage. The effects of added salts lead to the conclusion that Mn(III) and/or Mn(IV) play the main role in the reaction kinetics of the second stage. A reaction mechanism consistent with the kinetic results is suggested and discussed.

Double pincer movement: Encircling rupture splitting during the 2015 Mw 8.3 Illapel earthquake

The 2015 moment magnitude (Mw) 8.3 Illapel earthquake, that ruptured the central section of the Chilean subduction zone, is among the largest megathrust events in recent years. The coseismic rupture processes of the Illapel earthquake are imaged by the back-projection (BP) method in previous studies. But these models differ significantly in the extent of high-frequency radiations in the along-dip direction. Here, we conduct a refined High-resolution MUSIC BP imaging analysis of the Illapel earthquake based on teleseismic recordings in continental US. In contrast to conventional BP imaging, we add a slowness (ray parameter) error term calculated based on aftershock locations to effectively mitigate the spatial biases of BP. This correction accounts for the P-wave travel time errors at each receiver as a result of approximating the 3D Earth structure with 1D models. The calibrated BP images of aftershocks indicate that the root-mean-square location error was reduced from 24.17 km to 8.11 km. Our refined BP of the mainshock reveals geometrical rupture complexity with unprecedented details, involving stages of diverse rupture speeds and simultaneous up-dip and down-dip high-frequency bursts. The earthquake starts with a slow initiation phase propagating northward at a speed of 1 km/s in the first 13 s. Between 14 s to 34 s, the rupture diverges into two simultaneous fronts seemingly unzipping the rim of a circular patch of large slip at a speed of 3.5 km/s. The two fronts reemerge as a single front between 35 s and 45 s. The rupture splitting repeats in a second episode from 46 s to 60 s. The two episodes of encircling rupture involve intermittent high-frequency radiations both up-dip and down-dip, which reconcile the discrepancy of the extent of along-dip ruptures reported in previous BP studies. Key features of the rupture process correlate with the prominent pulses recorded by local strong-motion network. In one possible scenario, the rupture initially encounters and splits around a barrier of higher strength or an asperity of higher prestress but eventually breaks into the asperity/barrier and produces large slip in the center. Another scenario is the cascade-up growth model in which the nucleation process initiates inside a small weak patch and tends to grow into large-scale rupture surrounding the rim of a larger and stronger patch. Such degree of complexity is previously only reproduced in dynamic simulations but is directly observed with sufficient level of details for the first time. This case study demonstrates the capability of the BP method, enhanced by aftershock calibrations, to observe and probe the geometrical complexity of dynamic ruptures.

Pharmacokinetics of Snake Venom.

Understanding snake venom pharmacokinetics is essential for developing risk assessment strategies and determining the optimal dose and timing of antivenom required to bind all venom in snakebite patients. This review aims to explore the current knowledge of snake venom pharmacokinetics in animals and humans. Literature searches were conducted using EMBASE (1974–present) and Medline (1946–present). For animals, 12 out of 520 initially identified studies met the inclusion criteria. In general, the disposition of snake venom was described by a two-compartment model consisting of a rapid distribution phase and a slow elimination phase, with half-lives of 5 to 48 min and 0.8 to 28 h, respectively, following rapid intravenous injection of the venoms or toxins. When the venoms or toxins were administered intramuscularly or subcutaneously, an initial absorption phase and slow elimination phase were observed. The bioavailability of venoms or toxins ranged from 4 to 81.5% following intramuscular administration and 60% following subcutaneous administration. The volume of distribution and the clearance varied between snake species. For humans, 24 out of 666 initially identified publications contained sufficient information and timed venom concentrations in the absence of antivenom therapy for data extraction. The data were extracted and modelled in NONMEM. A one-compartment model provided the best fit, with an elimination half-life of 9.71 ± 1.29 h. It is intended that the quantitative information provided in this review will provide a useful basis for future studies that address the pharmacokinetics of snakebite in humans.