Detachment Time Research Articles

Study of an Equatorward Detachment of Auroral Arc From the Oval Using Ground‐Space Observations and the BATS‐R‐US–CIMI Model

AbstractWe present observations of an equatorward detachment of the auroral arc from the main oval and magnetically conjugate measurements made by the Arase satellite in the inner magnetosphere. The all‐sky imager at Gakona (magnetic latitude = 63.6°N), Alaska, shows the detachment of the auroral arc in both red and green lines at local midnight (∼0130–0230 MLT) on 30 March 2017. The electron density derived from the Arase in‐situ observations shows that this arc occurred outside the plasmapause. At the arc crossing, the electron flux of energies ∼0.1–2 keV is found to be locally enhanced at L∼4.3–4.5. We estimated auroral intensities for both red and green lines by using the Arase low‐energy (0.1–19 keV) electron flux data. The peak latitude of the estimated intensity shows reasonably good correspondence with the observed intensity mapped at the ionospheric footprints of the Arase satellite. These findings indicate that the observed arc detachment at Gakona was associated with the localized enhancement of low‐energy electrons (∼0.1–2 keV) at the inner edge of the electron plasma sheet. Further, we employ the simulation results of the Community Coordinated Modeling Center (CCMC), the BATS‐R‐US–CIMI 3‐D MHD code to understand the conditions in the inner magnetosphere around the time of detachment. Although the simulation could not reproduce the lower‐energy component responsible for the arc detachment, it successfully reproduced two earthward convection events at the lower radial distance (R) (R ≤ ∼4) around the time of arc detachment and the features of enhanced convection in similarity with the observations.

Microsecond dynamics of molecular negative ions formed by low-energy electron attachment to fluorinated tetracyanoquinodimethane.

Low-energy (0-15eV) electron interactions with gas-phase 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) molecules are studied under single collision conditions using dissociative electron attachment spectroscopy. The experimental findings are supported by density functional theory calculations of the virtual orbital energies and energetics of the dissociative decays. Long-lived molecular negative ions F4-TCNQ- are detected in a wide electron energy range (0-3eV) with electron detachment times in the range of milliseconds. Although plenty of decay channels are observed, their intensities are found to be very small (two to four orders of magnitude relative to the F4-TCNQ- signal). These findings prove that the structure of this strong electron-accepting molecule bearing an excess electron is robust in its electronic ground state, even when highly (up to 6eV) vibrationally excited. As many as nine metastable fragment anions formed slowly (in the 16-23 µs range) are found in the negative ion mass spectrum of F4-TCNQ, as never observed before in compounds possessing high electron-accepting ability. The present results shed some light on microsecond dynamics of isolated F4-TCNQ molecules under conditions of excess negative charge, which are important for understanding the functionality of nanoscale devices containing this molecule as a structural element.

Evaluation of Factors for Promoting Bubble Detachment from Anodes for Alkaline Water Electrolysis

Introduction Toward the realization of a hydrogen society without any carbon dioxide emission, water electrolysis to produce hydrogen using renewable electricity is attracting attention. Alkaline water electrolysis (AWE) is one of the water electrolysis technology, which uses low-cost materials. To reduce energy consumption of the AWE, the electrolysis bubble around the electrodes, which inhibits mass transfer of reactant and limits the effective electrochemical surface area [1], should be removed effectively. In this study, as a basic evaluation of the effect of bubbles on the polarization of porous electrodes, we have investigated the effect of operation pressure and pore size on apparent activity of oxygen evolution reaction (OER) for Ni porous electrodes. Experimental Working electrodes were the Ni Celmet® (Sumitomo Electric Industries, Ltd., pore size of 1.95, 0.85, and 0.51mm, thickness of 3 mm). A counter and a reference were a Ni coil and a reversible hydrogen electrode (RHE), respectively. All measurements were performed with a three-electrode electrochemical cell at 303±1K with 7.0 M of KOH in a pressurized vessel.After pretreatment, the effect of pressure on the activity was evaluated with chronopotentiometry for pore size of 0.51 mm electrode in the current range from 50 to 1000 mA cm-2-geo under pressure range from ambient to 0.3 MPa. Also, the effect of pore size on the activity was evaluated with chronoamperometry for mean pore diameter of 1.95, 0.85, 0.51 mm electrodes in the potential range from 1.5 to 2.0 V vs. RHE under ambient pressure. In addition, we observed bubble behavior during electrolysis with the high-speed camera (Photron, FASTCAM Nova S12) in visualized three-electrode electrolyzer under ambient pressure. Results and discussion Figure 1 shows the chronopotentiogram as a function of logarithm of time under various pressure at 400 mA cm-2-geo. The visualization of bubble behavior under 0.1 MPa pressure showed that the bubble formed for 15 ms of electrolysis, because of charging of the electric double layer and dissolving of generated oxygen. After 500 ms of electrolysis, initial bubble detachment began, and the bubble detachment became steady after 1000 ms of electrolysis with increase of potential vibration. Under higher pressure, the trend of the chronopotentiograms was same, but the slopes decreased with the increase of pressure after 15 ms, and the potential increase was also smaller than that of 0.1 MPa.Figure 2 shows the steady state polarization curves and the potential increase from 15 ms to 20000 ms as a function of current of the CPs. The potential decreased with the increase of pressure, simultaneously the potential increase decreased with the increase of pressure. This suggests that pressurization reduced the flow resistance of the bubbles, accelerated their detachment, reduced the bubble volume fraction in the porous medium, and increased the effective surface area of an electrode.Figure 3 shows the decrease of current density during the chronoamperometry at 1.8 V vs. RHE as a function of charge passed. The visualization of bubble behavior showed that the timing of bubble generation was about 1, 3, and 7 mC cm-2-geo on the mean pore diameter of 1.95, 0.85, and 0.51 mm electrodes, respectively. Also, the timing of bubble detachment was 50, 90, and 110 mC cm-2-geo. The smaller the pore size electrodes were larger current decrease with later bubble formation. Bubble formation occurs after gas dissolution into the electrolyte on an electrode surface reaches local supersaturation [2]. Supersaturation of a smaller pore size electrode was higher than that of larger pore size one because of larger charge passed before bubble generation. If steady state supersaturation is irrelevant to the pore size, bubble occupancy of smaller pore electrode must become larger than that of larger pore electrode during relaxation period. Figure 4 shows the polarization curves and the current decrease during bubble generation to detachment as a function of potential. The current decrease increased with the decrease of the pore diameter. This suggests that the flow resistance of the bubbles is larger with smaller pore size electrodes, because the pore occupancy of bubble increases with decrease of the pore diameter. Acknowledgements A part of this study was based on results obtained from the Development of Fundamental Technology for Advancement of Water Electrolysis Hydrogen Production in Advancement of Hydrogen Technologies and Utilization Project (JPNP14021) commissioned by the New Energy and Industrial Technology Development Organization (NEDO). Reference [1] S. Marini, P. Salvi, P. Nelli, R. Pesenti, M. Villa, Electrochim. Acta, 82, 384-391 (2012)[2] M. E. Tawfik, F. j. Diez, Electrochim. Acta, 146, 792-797 (2014) Figure 1

Vitrectomy versus Combined Vitrectomy and Scleral Buckle for Repair of Primary Rhegmatogenous Retinal Detachment with Vitreous Hemorrhage

To compare pars plana vitrectomy (PPV) with combined PPV and scleral buckle (PPV/SB) for repair of primary rhegmatogenous retinal detachment (RRD) with associated vitreous hemorrhage (VH). Retrospective, observational study. Patients with RRD and associated VH who underwent PPV or PPV/SB from January 1, 2010, through August 31, 2020, were analyzed. We performed a single-institution, retrospective, observational study of 224 eyes with RRD and VH at the time of detachment. We excluded eyes with <6 months of follow-up, a prior history of retinal detachment (RD) repair with vitrectomy or SB, VH that resolved before surgical intervention, and tractional or combined tractional and rhegmatogenous detachments. Single-surgery anatomic success (SSAS) at 6 months, defined as no recurrent RD requiring surgical intervention. Pars plana vitrectomy and PPV/SB were performed on 138 eyes (62%) and 85 eyes (38%), respectively. The mean age of the PPV and PPV/SB patients was 61.9 and 60.2 years, respectively. Single-surgery anatomic success was achieved in 107 of 138 eyes (77.5%) that underwent PPV and 78 of 85 eyes (91.7%) that underwent PPV/SB. The difference in SSAS between types of treatment was significant (P= 0.006). Mean visual acuity improvement in the PPV/SB group was 0.54 logMAR units greater than that in the PPV group (P= 0.126). The incidence of postoperative proliferative vitreoretinopathy in the PPV/SB group (11.7%) was lower than that in the PPV group (19.5%; P= 0.128). The rate of repeat PPV for non-RD reasons was similar for both the groups (P= 0.437). Final reattachment status was achieved in 137 of the 138 and 84 of the 85 eyes in the PPV and PPV/SB groups, respectively. Final visual acuity improvement was significantly better in eyes with PPV/SB than in eyes with PPV alone (logMAR 2.12 vs. 1.26, respectively; P= 0.011). In patients with RRD and VH, SSAS was superior in patients treated with PPV/SB compared with those treated with PPV alone. Although not significantly different, the PPV/SB group had better visual outcomes and a lower postoperative proliferative vitreoretinopathy rate.

On the foundation of thermal “Switching”: The culture substrate governs the phase transition mechanism of thermoresponsive brushes and their performance in cell sheet fabrication

Thermally “switchable” poly(glycidyl ether) (PGE) brushes constitute effective coatings for the temperature-triggered harvest of confluent cell sheets. Based on a simple “grafting-to” approach, such coatings can be tethered to various applied plastic culture substrate materials. Herein, we elucidate the self-assembly of PGE brushes with tunable grafting densities up to 0.12 and 0.22 chains nm−2 on polystyrene (PS) and tissue culture PS (TCPS), respectively. In terms of temperature-dependent wettability and protein adsorption, we found that brushes exhibit distinct grafting density-dependent properties which correlate with their cell sheet fabrication performance. In addition, temperature-ramped quartz-crystal microbalance with dissipation (QCM-D) measurements revealed marked substrate-specific PGE phase transitions which allowed us to deduce comprehensive switching mechanisms. Thus, we demonstrate that brushes tethered to hydrophilic TCPS (contact angle (CA) ∼ 60°) undergo a “cushioned” transition comprising a non-switchable, hydrated basal layer as well as a switchable top layer which regulates cell sheet detachment. In contrast, PGE brushes tethered to PS undergo a “grounded” transition which is substantially influenced by the dehydrating effect of the less hydrophilic PS substrate (CA ∼ 90°). These divergent phase transition mechanisms give rise to a broad scope in cell sheet fabrication performance, yielding staggered detachment times within a 30 min to 3 h range. Hence, we emphasize the importance of a detailed knowledge on the effect of applied culture substrates on the thermal switchability and phase transition characteristics of thermoresponsive brush coatings to accomplish an optimized design for functional cell culture dishes. Statement of significanceAs the first comparative study of its kind, we elucidate the substrate-dependent thermal switchability of thermoresponsive brush coatings and evaluate their grafting density-dependent phase transition mechanism and its effect on cell sheet fabrication performance.

Effects of capillary number and flow rates on the hydrodynamics of droplet generation in two-phase cross-flow microfluidic systems

Background: The control and manipulation of the hydrodynamics of droplets primarily relate to flow governing and geometrical parameters. This study has explored the influences of capillary number (10−4≤Cac≤1) and flow rate ratio (0.1≤Qr≤10) on the hydrodynamics of droplet generation in two-phase flow through T-junction cross-flow microfluidic device.Methods: The finite element method is used to solve the Eulerian framework of a mathematical model based on mass continuity, Navier-Stokes, and conservative level set equations at fixed flow (Rec=0.1).Significant findings: Results are presented in terms of the instantaneous phase flow field, droplet size, droplet detachment time, and generation frequency as a function of governing parameters (Cac and Qr). The flow regimes namely squeezing, first transition, dripping, second transition, parallel, and jet flow are marked. In contrast to reported value of threshold Cac≈10−2, squeezing regime exists for all Cac and 2≤Qr≤10. The flow regimes are also mapped into droplets and non-droplet zones by using threshold Car which scales quadratically with Qr. The droplet length varies linearly with Qr in the squeezing regime. Both droplet size and frequency show the power-law relations with Cac and Qr in the droplet zone. Finally, predictive correlations are presented to guide the engineering and design of droplet microfluidics devices.

Respiratory droplet resuspension near surfaces: Modeling and analysis

Knowing the environmental spreading pathway of COVID-19 is crucial for improving safety practices, particularly for health care workers who are more susceptible to exposure. This paper focuses on the possible secondary transmission due to resuspension of virus-laden droplets from common surfaces, which several studies have shown to be possible under external disturbances. Such disturbances could be body motion during walking, running, clothes removal, or airflow in the environment. In this paper, a three-dimensional two-phase model is utilized to study respiratory droplet resuspension dynamics on various surfaces due to sudden agitation. The velocity range and variation during walking, surgical glove removal, and dropping an object are studied experimentally. A parametric study is performed to characterize the effects of droplet size and surface wettability on the minimum initial droplet velocity required for detachment from surfaces. The results are reported as average droplet velocity during the detachment process, total detachment time, and detached droplet volume. The obtained results indicate that respiratory droplets larger than 200 μm can detach from typical surfaces due to normal daily activities. Droplets are partially separated from hydrophilic surfaces with contact angle ≤90°, while the entire droplet is detached from hydrophobic surfaces with contact angle &amp;gt;90°. Furthermore, the minimum initial droplet velocity to induce the resuspension depends on the droplet size. Droplet velocity immediately after detachment is a function of droplet size, initial droplet velocity, and surface wettability. Bigger droplets have larger detached volume percentage as well as higher velocity after detachment compared to smaller droplets. Finally, a higher initial velocity is needed to separate droplets from hydrophilic surfaces as compared to hydrophobic surfaces. In accordance with the results, the droplet minimum initial velocity to cause detachment is 2 m s−1, while our experiments show that surface velocity can reach up to 3 m s−1 during normal human activities. We also develop an analytical model to predict the required kinetic energy to detach droplets from different surfaces, which is in good agreement with numerical results. The mechanism of droplet detachment is dictated by a competition between droplet kinetic energy induced by surface motion and surface energy due to droplet–surface interaction as well as droplet–vapor and surface–vapor interactions. We believe that the results of this fundamental study can potentially be used to suggest proper surface wettability and safe motion that reduce respiratory droplet resuspension from various surfaces.

Health Information Integration Based on Network Platform in Postpartum Maternal and Infant Health Care

Objective: The self-care ability of puerpera is poor, and their health knowledge of maternal and infant and care skills is relatively poor. The aim of our study was to investigate the effect of health information integration based on network platform in the postpartum maternal and infant health care. Methods: A total of 80 maternal women admitted to our hospital from September 2018 to March 2019 were randomly divided into a control group and a study group, with 40 patients in each group. The puerpera in control group received regular telephone visits after discharge. The puerpera in study group received health information integration based on network platform. The uterus recovery of puerpera in two groups at 42 days postpartum, as well as the lochia, bloating, nipple splitting and breastfeeding behaviors were compared. The time of jaundice regression and umbilical cord detachment of neonates in t two groups, as well as the incidence of facial eczema and umbilical inflammation were compared. Results: The uterus recovery rate and exclusive breastfeeding rate of puerpera in study group were higher than those in the control group at 42 days postpartum, and the incidences of abnormal lochia, swollen breasts, and nipple splitting were lower than those in the control group. The difference between the two groups was statistically significant (P &lt; 0.05). The neonates in study group were lower than the observation group in terms of the days of jaundice regression, facial eczema, and umbilical inflammation. The difference between the two groups was statistically significant (P &lt; 0.05). However, there was no significant difference in the days of umbilical cord shedding (P &gt; 0.05). Conclusions: The health information integration based on network platform in postpartum maternal and infant health care can effectively improve maternal breastfeeding compliance and reduce the adverse symptoms of maternal and neonatal discharge.

Droplet dynamic characteristics on PEM fuel cell cathode gas diffusion layer with gradient pore size distribution

Understanding of droplet dynamic characteristics on gas diffusion layer (GDL) of polymer electrolyte membrane (PEM) fuel cell is of great importance for cell performance improvement. This study comprehensively investigated droplet dynamic characteristics on fuel cell cathode GDL with gradient pore size distribution (GPSD). The influence of different pore sizes, GPSD and wettabilities of GDL on droplet dynamic characteristics is numerically evaluated by using the volume of fluid (VOF) method through the analysis of the interaction among the forces over droplet. Results indicate that droplet has a relatively short detachment time and a smaller detachment radius on superhydrophobic and superhydrophilic GDLs compared with on a moderately hydrophobic GDL regardless of pore size. Moreover, large pores can facilitate droplet detachment, but increase droplet detachment radius and pressure drop. Compared with uniform (U)PSD, for transverse (T)-GPSDs with a small pore distance at a relatively low airflow velocity or a large pore distance at a high airflow velocity, or for the longitudinal (L)-GPSD with a large pore in the upstream and a small pore in the downstream at a large pore distance, the droplet detachment time decreases by 34.3% and 25.2% with a reduction of pressure drop, respectively.

Non-Newtonian Droplet Generation in a Cross-Junction Microfluidic Channel.

A two-dimensional CFD model based on volume-of-fluid (VOF) is introduced to examine droplet generation in a cross-junction microfluidic using an open-source software, OpenFOAM together with an interFoam solver. Non-Newtonian power-law droplets in Newtonian liquid is numerically studied and its effect on droplet size and detachment time in three different regimes, i.e., squeezing, dripping and jetting, are investigated. To understand the droplet formation mechanism, the shear-thinning behaviour was enhanced by increasing the polymer concentrations in the dispersed phase. It is observed that by choosing a shear-dependent fluid, droplet size decreases compared to Newtonian fluids while detachment time increases due to higher apparent viscosity. Moreover, the rheological parameters—n and K in the power-law model—impose a considerable effect on the droplet size and detachment time, especially in the dripping and jetting regimes. Those parameters also have the potential to change the formation regime if the capillary number () is high enough. This work extends the understanding of non-Newtonian droplet formation in microfluidics to control the droplet characteristics in applications involving shear-thinning polymeric solutions.

Process control of pulsed laser enhanced metal transfer behavior in CO2 gas shielded welding

Spot pressure, as an arc repelling force, hinders the metal transfer process and has a negative effect on welding process stability in CO2 gas shielded welding. In addition, the direction of the spot pressure changes uncontrollably with the deflection of the droplet. Therefore, it is particularly critical to provide an additional force to improve droplet transfer characteristics without disturbing the arc stability. To this end, a new approach of the pulsed laser enhanced metal transfer (PLE-MT) process in CO2 gas shielded welding was proposed to control metal transfer behavior. The results demonstrate that: different from the uncontrollable deflection of droplets caused by laser incident on the solid–liquid interface (S-L-I) of the droplet, the irradiation of solid-state welding wire (S-W) can fundamentally solve the droplet deflection problem. The cut droplet can enter into the molten pool smoothly along the axis, and the change of the incident height does not significantly change the droplet's detachment velocity. The droplet’s detachment time at three different laser incident heights (0.5, 1, and 1.5 mm) remained almost unchanged, all of which were about 6–8 ms. When the wire feeding speed is 4 m/min and the voltage is 25 V, after laser irradiation is added, the metal transfer frequency increases from 5 to 25 Hz. The droplet transfer mode changes from SC transfer to spray transfer, and it avoids the short-circuit spatter. However, the metal evaporation mass produced by laser heating liquid droplet or welding wires is about 3.5% of the droplet mass. Under the condition of direct current electrode negative (DCEN), although the melting efficiency of the wire can be effectively improved, the droplet will be repelled until the arc is extinguished, and the stability of the arc will also deteriorate due to the rise of the arc. The irradiation of the pulsed laser can impede the climb of the droplet (cut off the droplet when its size is small before the arc climbs up), promote metal transfer, and improve the stability of the welding process in DCEN. While expanding the process interval of CO2 welding, an efficient spatter-free, low-pollution metal transfer process was obtained under a relatively small current through the PLE-CO2 welding process.

Different nanofluids effect on bubble characteristics at the isothermal bubble column

AbstractIn this study, the effect of different nanofluids such as SiO2, Fe3O4, and Al2O3 on bubble characteristics is studied experimentally. The nanoparticles concentration for the SiO2 nanofluid is 0.05 wt% and for other nanofluids is 0.005 wt%. Bubbles are formed by injection of air at a constant gas flow rate (between 600‐1200 mL/h) into a stagnant isothermal liquid column. Experimental data of formation, growth, and detachment of the air bubbles were recorded by a high‐speed digital camera (1200 fps), and the image processing method was used to analyze the bubble characteristics. In the present study, bubble characteristics such as diameter, size, aspect ratio, and detachment frequency were studied in four different liquids. The results show that a bubble has the biggest size in the pure water and adding nanoparticles to the pure water decreases bubble size. Also, the variation of detachment frequency has an inverse relation with the bubble size behaviour. Between different nanoparticles, Fe3O4 has maximum and SiO2 has minimum effect on bubble features. By adding Fe3O4 to pure water, bubble diameter decreases nearly 7%‐8% and bubble detachment frequency increases nearly 15%‐20%. In order to analyze the variation of the bubble characteristics, a force modelling on bubbles during the growth was proposed. Moreover, a correlation has been proposed for the prediction of bubble diameter at detachment time in three different nanofluids and in the pure water. The mean absolute error of this correlation is 2.65% and has a good agreement with experimental results.

Application of a parametric survival model to understand capture-related mortality and predation of yellowfin tuna (Thunnus albacares) released in a recreational fishery

Distinguishing the cause and magnitude of capture-related mortality (CRM) in fishes is important for effective management. To better understand CRM in yellowfin tuna (Thunnus albacares) released in the recreational troll fishery off the United States east coast, 48 fish (76–127 cm curved fork length, CFL) were monitored for up to 86 days postrelease with survivorship pop-up satellite archival tags. Recovered data indicated 40 fish were alive at the time of tag detachment and eight died, including six from predation, from 0 to 30 days postrelease. Survival model variants were constructed to independently estimate the rates of immediate capture and handling (CH), postrelease (PR), total CRM (CH + PR), and natural mortality (M) for small (≤103 cm CFL) and large (&gt;103 cm CFL) fish under different hypotheses and causes of mortality. CH was low (0%–8%) for both size classes but predation was an important component of PR, particularly in the small size class. Total CRM was 51% (95% CI: 26%, 81%) for small and 8% (95% CI: 2%, 30%) for large fish.

Surgical management and outcomes of pediatric open globe injuries requiring vitrectomy

To describe surgical management and establish visual outcomes of open globe injury (OGI) in pediatric patients requiring vitrectomy. Forty-eight eyes of 48 pediatric patients underwent vitrectomy for OGI with secondary vitreoretinal complications in the eye center of Jilin University were included. Characteristics of patients, details of ocular examination and operation, presenting and final visual acuity were recorded. Presenting visual acuity less than 20/400 was found in 44 eyes (91.7%), which included no light perception (NLP) in four eyes. At last visit, there was no eyes with visual acuity of NLP, and 19 eyes (39.6%) had a vision recovery to 20/400 or better. Mechanisms of injury, intraocular contents prolapse, presence of hyphema, intraocular foreign body, vitreous hemorrhage, retinal detachment, and total time from injury to PPV > 2 weeks were significant predictors of visual prognosis. Logistic regression analysis showed that hyphema was a significant predictive factor for poor visual outcome. Visual acuity was improved in most of the patients with OGI in this study. Hyphema is an important presenting ocular sign in estimating the post-vitrectomy visual outcome for OGI in children. Proper timing of vitrectomy is suggested, and in this study patients may benefit more with early vitrectomy as less proliferative vitreoretinopathy (PVR) was found together with a better visual acuity.

Cancer cells targeted visible light and alkaline Phosphatase-Responsive TiO2/Cu2+ carbon Dots-Coated wireless electrochemical biosensor

The utilization of visible light and pyrophosphates (PPi) accompanied by alkaline phosphatase (ALP) activity-responsive cancer cells-targeting carbon dots using carbonized hyaluronic acid (CD(HA)) by means of electrochemical signals generated from CD(HA)/TiO2/Cu2+-coated surfaces was investigated. The stimuli-responsive surface provided an effective method for wireless sensors under intracellular conditions with an antifouling effect to visualize the cell adhesion interaction with the surface as well as the detection of cancer cells. The highly distinctive intracellular PPi and ALP levels of cancer cells compared to normal cells and CD44 receptor-mediated endocytosis by the CD(HA) chain into cancer cells induced an electrochemical signal change in cell-cultured biosensors detected by electrochemical methods including EIS and a wireless sensing system. The antifouling properties of CD(HA)/TiO2/Cu2+ verified by the time-dependent cell detachment occurring on the modified surfaces in the presence of visible light were employed for the detection of cancer. The resistance of cancer cell-cultured CD(HA)/TiO2/Cu2+ biosensors considerably increased (248 kΩ) as detachment time triggered by visible light irradiation increased compared to normal cells (152 kΩ), which was ascribed to the dissociation of Cu2+ in the system by PPi and ALP in cancer cells and the cellular internalization of CD(HA). With high sensitivity and accuracy for cancer detection by the visible light and enzyme-responsiveness with low LOD value (2.31 cells/mL) on basis of electrochemical approach and 70.05 cells/mL for optical approach, the CD(HA)/TiO2/Cu2+ wireless biosensor offers a promising approach that facilitates cancer diagnosis with antifouling effects to investigate the interaction between cells and modified surfaces.

A novel Ti cored wire developed for wire-feed arc deposition of TiB/Ti composite coating

A novel Ti cored wire containing TiB2, Al60V40 and Ti6Al4V mixed powders was developed for wire-feed arc deposition of TiB/Ti composite coating, to enhance the hardness and wear resistance of Ti alloy. Results showed that after experiencing several chemical reactions, the wire was melted in the arc zone and turned into nonuniform droplets composed of Ti-Al-V-B melt and undecomposed TiB2 particles. With the increase of welding current, the detachment time of droplet shortened while the transfer frequency accelerated, accompanied by the improvement in coating surface quality. The spatial distribution of TiB whiskers in coating was governed by welding current. A uniform distribution could be achieved as welding current was sufficient at the expense of elevated dilution ratio, while increasing wire feeding speed could compensate the dilution loss of TiB whisker to some extent. The decomposition process of TiB2 particles and the microstructure evolution mechanism of coating was discussed in detail. The optimum coating possessed uniform microstructure, relatively low dilution ratio, and high hardness (639.1 HV0.5) as compared with Ti6Al4V substrate (326 HV0.5). Indentation morphology analysis verified the excellent performance was ascribed to the load-sharing strengthening of TiB whiskers. This study provides a high-efficiency fabrication method for the ever-developing titanium matrix composites (TMCs) coating.

Effects of tilt angle on droplets condensation on hydrophobic surface

Condensation surface modification was an important research direction to realize droprise condensation and erhance heat transfer. In order to explore the condensation process and mechanism of droplets on the hydrophobic surface, the condensation process of droplets on the natural Donghu lotus leaves with tilt angle of 30°,60° and 90° were studied. The results show that the tilt angle had a significant effect on the droplets condensation behavior on Donghu lotus leaves hydrophobic surface. Increasing the tilt angle would short the detachment time of condensate droplets. The growth rate of droplets increased with the increase of hydrophobic surface tilt angle. And the condensation droplets diameter also decreased with the increase of incl ination angle.

In vivo, ex vivo and in vitro Mucoadhesive Strength Assessment of Potential Pharmaceutical Bio-resource Polymer from Diospyros melonoxylon Roxb seeds

In this study, an oral bio-based mucoadhesive polymer was developed from Diospyros melonoxylon Roxb (Ebenaceae) seed mucilage and evaluated for mucoadhesive strength. The mucilage showed shear stress results (0.140 ± 0.0007N), with comparable adhesiveness to HPMC E5 (0.098 ± 0.0008N). Force of adhesion required to detach the seed mucilage and HPMC E5 tablets from the mucin of intestinal tissue were 0.0509 ± 0.0007 (N) and 0.0049 ± 0.0006 (N). Seed mucilage revealed significant higher detachment time, erosion time, in vitro wash off time and ex vivo residence compared to HPMC E5 and lactose tablets (p&lt;0.01). In vivo test indicated that seed mucilage tablets possessed good mucoadhesive strength compared to HPMC E5 and resisted disintegration for ≤ 8 h. The swelling index and wetting time showed comparable results between the mucilage and synthetic polymer tablets. Mucilage demonstrated high moisture absorption, percentage hydration, and matrix erosion of 20.0 ± 0.037, 53.66 ± 0.127, and 20.00 ± 0.077 compared to HPMC E5 10.0 ± 0.079, 36.00 ± 0.089, and 1.26 ± 0.085. The mucoadhesive properties of seeds mucilage were comparable to guar gum and HPMC E5. Thus, seed mucilage of D. melonoxylon can be exploited for usage as pharmaceutical excipient in oral bioadhesive drug delivery systems.

Umbilical cord medication in healthy full-term newborns: a before-after uncontrolled quality improvement study

Umbilical cord care can be a stressful practice for parents. Complications of cord care can increase neonatal morbidity and mortality. The extracts of Arnica montana (AM) have been reported to possess antibacterial, anti-inflammatory, antifungal, and immunomodulatory activities. We aim to demonstrate the efficacy of AM on cord detachment and parents’ stress level induced by cord medication in healthy full-term newborns. We enrolled full-term infants with a birth weight ≥ 2500 g in healthy conditions. Cord stumps of infants in the PRE-group were cleaned and dried, while cord stumps of infants in the POST-group were cleaned, dried, and medicated with a natural topic dermo-protective powder containing AM. After discharge, we interviewed parents on the stump status during follow-up visits in a pediatric office at 7 and 14 days of life, or by phone calls after follow-up visits. Long-rank test showed that time of cord separation of newborns in the PRE-group was significantly higher compared to that in the POST-group (p < 0.001). Parents of newborns in the PRE-group were significantly more stressed during cord medication compared to parents in the POST-group (2.0 (1.2 to 2.1) vs 1.0 (0.8 to 1.3), p = 0.011). Multivariate analysis showed a significantly linear relation with group assignment for cord separation (p < 0.001) and parents’ stress during the medication (p = 0.033).Conclusion: The use of a natural topic dermo-protective powder containing AM reduces the time of cord separation, improves parents’ stress level, and reduces the risk of complications.What is Known:• Cord stump care can be a stressful practice for parents.• Antiseptic treatment recommended for cord care could be associated with side effects such as burning and sensitization.What is New:• The medication of cord stump with a natural topic dermo-protective powder containing Arnica montana reduces time of cord detachment and of complication such as redness’, bleeding, or secretions.• The use of Arnica montana for cord medication may have a positive impact on the family, reducing parents’ stress, and the use of other medications.

Water Distribution in Fuel Cell Gas Channels Using a Mechanistic Discrete Particle Model

Water removal and accumulation in fuel cell gas channels is a complex phenomenon which is a consequence of the strength of the capillary forces and inertial forces (1 < Re < 1000). The presence of water in the channel restricts the access of oxygen to diffuse through the gas diffusion layers to the catalyst layer. The air supplied exchanges momentum to the droplets and water clusters, causing detachment when the adhesion force is overcome.Water emerging from discrete locations as droplets interact with both the channel walls and each discrete water cluster, depending on the configuration and operating conditions. Complexity increases as multiple detachment and coalescence events occur over large channel lengths and time scales. Modelling these systems with traditional method computational fluid dynamic (CFD) methods is computationally expensive so we have developed a new mechanistic discrete particle model to handle the liquid water two-phase flow.Taking inspiration from interface resolving volume of fluid (VoF) simulations of water flow in gas channels, we use analytically equations determined by the equilibrium contact angle in different configurations on the channel wall to predict detachment times and coalescence events. We compare the prediction of water area coverage ratio and channel saturation to the VoF simulations and can also estimate dynamic pressure drop.Using this model, we are able to investigate the dynamic effects of liquid water accumulation and distribution in the channel, with often periodic detachment events arising from the formation of liquid plugs. Consequently, the model is able to investigate the effect of the channel wall wettability, from hydrophilic to hydrophobic and the impact that has on the distribution and accumulation of water in the system.We compare the speed of this model against the VoF simulations to show that this type of modelling of two-phase flow in the channel can enable higher resolution accuracy when coupled with continuum scale approaches. Furthermore, with this approach it is possible to investigate the effect of: channel dimensions, liquid water flow rate and spatial location of liquid water emergence. This should allow for designed fuel cell structures to be evaluated. Figure 1