Alcohol Gel Research Articles

Transvenous Radiofrequency Ablation of Adrenal Gland: Experimental Study.

The aim was to evaluate a flexible device for transvenous adrenal gland radiofrequency ablation in vitro and in an in vivo animal model. A flexible radiofrequency-tip catheter with an inner-cooling mechanism and a guidewire lumen was made. Then, using a polyvinyl alcohol gel model, the ablation diameter was evaluated and how much energy to deliver in vivo was determined. Finally, transvenous radiofrequency ablation of the left adrenal glands of two pigs was performed, delivering 5000 or 7000J in a single dose to each. The ablation effects were also assessed by histological examination of hematoxylin-eosin-stained sections. The mean ablation diameters in the gel model were 20.2 and 21.9mm in the short axis and 15 and 20mm in the long axis for 5000 or 7000J, respectively. The device was inserted into porcine left adrenal vein with no complications. The mean ablation diameters were 10mm in the shorter axis (whole thickness of porcine left adrenal gland) in the porcine model for 7000J. Transient increases in blood pressure and heart rate occurred during ablation. Histologically, the adrenal gland showed severe necrosis at ablated area. There was venous congestion upstream in a non-ablated area, and thermal damage to surrounding organs was not observed. A flexible radiofrequency-tip catheter could be inserted successfully into the left adrenal vein. The left adrenal gland was entirely ablated without any thermal damage to surrounding organs. We suggest transvenous adrenal ablation has potential as a therapeutic option for primary aldosteronism.

Performance evaluation of hybrid upflow anaerobic sludge blanket reactors with different inert media for sewage treatment

In this study, three HUASB reactors with different inert media viz. sea shells (R1), polyvinyl alcohol (PVA) gel beads (R2) and coconut fiber (R3), were simultaneously investigated in continuous mode at an ambient temperature ranging from 33 °C to 41 °C for six months. The reactors were employed with varying hydraulic retention times (starting from 6 h and reduced to 2 h) and organic loading rates (0.5–6.0 kg.COD.m−3.day−1) for sewage treatment. Sludge bed samples from each reactor were collected at the end of the process, and particle size distribution was determined using ocular micrometry, as well as the number of microorganisms present per ml using the neubauer chamber. According to the chemical and microbiological analysis, along with an overall assessment, it was found that the HUASB reactor with coconut fiber inert media has proved superior in its performance compared to the HUASB reactor with PVA gel beads and sea shells.

Robust and durable aberrative and absorptive phantom for therapeutic ultrasound applications.

Phase aberration induced by soft tissue inhomogeneities often complicates high-intensity focused ultrasound (HIFU) therapies by distorting the field and, previously, we designed and fabricated a bilayer gel phantom to reproducibly mimic that effect. A surface pattern containing size scales relevant to inhomogeneities of a porcine body wall was introduced between gel materials with fat- and muscle-like acoustic properties-ballistic and polyvinyl alcohol gels. Here, the phantom design was refined to achieve relevant values of ultrasound absorption and scattering and make it more robust, facilitating frequent handling and use in various experimental arrangements. The fidelity of the interfacial surface of the fabricated phantom to the design was confirmed by three-dimensional ultrasound imaging. The HIFU field distortions-displacement of the focus, enlargement of the focal region, and reduction of focal pressure-produced by the phantom were characterized using hydrophone measurements with a 1.5 MHz 256-element HIFU array and found to be similar to those induced by an ex vivo porcine body wall. A phase correction approach was used to mitigate the aberration effect on nonlinear focal waveforms and enable boiling histotripsy treatments through the phantom or body wall. The refined phantom represents a practical tool to explore HIFU therapy systems capabilities.

Study of electrochromic behavior of the supporting electrolyte free electrochromic devices based on the graphene quantum dots functionalized viologens for energy-saving smart window application

Here in this work, two electrochromic systems have been prepared by functionalizing di-pentyl viologen (DPV) and di-heptyl viologen (DHV) with graphene quantum dots (GQDs). Strong molecular forces like cation-πinteractions, π–π stacking interactions, electrostatic interactions, etc., ensure an adequate interaction between GQDs and viologens, hence, responsible for stabilizing the electrochromic system. All solid electrolyte-free electrochromic devices have been fabricated by dispersing DPV-GQD and DHV-GQD in poly(vinyl)alcohol (PVA) gel. Electrochemical behavior and electrochromic responses of the fabricated devices were investigated using chronoamperometry, cyclic voltammetry and in situ UV–vis spectroscopy. Both devices were found to work efficiently without the help of supporting electrolytes. Both DPV-GQD and DHV-GQD devices exhibit high optical contrast of 53.4% and 60%, with superior coloration efficiency of 143.9 cm2/C and 66 cm2/C, respectively. Swift electrochromic responses of 4.4 s/3.5 s and 6.2 s/2.5 s have been recorded for coloration/bleaching for DPV-GQD and DHV-GQD devices, respectively. Fabricated DPV-GQD device was found to retain 73% of its initial optical contrast while DHV-GQD depicts retention of only 63% after 3000 cycles. The superior coloration efficiency and balanced response time of DPV-GQD make it a potential material for the device application.

Flexible Pseudocapacitive Iontronic Tactile Sensor Based on Microsphere‐Decorated Electrode and Microporous Polymer Electrolyte for Ultrasensitive Pressure Detection

AbstractWearable sensor as the initial terminal is in great requirement for people pursuing healthy life. High‐performance tactile sensors are the guarantee of accurate pressure information acquisition. Herein, a flexible iontronic tactile sensor is developed by utilizing a highly conductive poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) thin film decorated with polymethyl methacrylate microspheres as pseudocapacitive electrode and a porous polyurethane foam composited with Na+/Cl−ion‐enriched polyvinyl alcohol gel as polymer electrolyte through a facile method of solution‐casting followed by freeze‐drying. By taking advantages of both high pseudocapacitance and rationally designed microstructures, the developed tactile sensor shows an ultrahigh sensitivity (≈162.90 kPa−1), a broad detection range (≈160 kPa), a low detection limit (≈30 Pa), a fast response time (≈25 ms), and excellent repeatability and durability. Thanks to the ultrahigh sensitivity, the sensor is capable of detecting subtle pressures caused by dynamic micromotions such as touching a sandpaper surface, dropping water droplets, and adding water into a beaker. Application of a smart glove mounted with such sensor unit and array for a fast and accurate Braille recognition is also demonstrated. The proposed facile and efficient strategy of fabricating flexible ultrasensitive tactile sensors will be favorable to various wearable subtle pressure sensing applications.

CoFe2O4 Hollow Spheres-Decorated Three-Dimensional rGO Sponge for Highly Efficient Electrochemical Charge Storage Devices.

The energy demand, the crisis of fossil fuels, and the increasing popularity of portable and wearable electronics in the global market have triggered the demand to develop high-performance flexible all-solid-state supercapacitors that are capable of delivering high energy at high power density as well as being safely entrenched in those electronics. Herein, we have designed a nanocomposite, 80CFhs-20rGOsp, which exhibits a high specific capacitance (CS) value of 1032 F g–1 at 3 A g–1. Utilizing this nanocomposite as the cathode and reduced graphene oxide sponge (rGOsp) as the anode, a flexible all-solid-state asymmetric device has been fabricated. In this device, poly(vinyl alcohol) (PVA) gel embedded with a mixture of 3 M KOH and 0.1 M K4[Fe(CN)6] was used as an electrolyte cum separator. The fabricated device showed the capability to deliver an energy density of 65.8 W h kg–1 at a power density of 1500 W kg–1 and retained its capability even after various physical deformations. The device also exhibited a long cycle life and retained ∼96% of its CS value after 5000 cycles. Moreover, the fabricated flexible all-solid-state device successfully illuminated light-emitting diodes, which proved its potential use in real-life supercapacitor applications. The obtained results revealed the excellent electrochemical performances of the fabricated device and rendered it a promising candidate in the energy sector.

Bioethanol and Gel Production using Organic Fruit Waste

Half of the waste that we produce comes from food and organic waste that could be reused. Meanwhile, the use of alcohol gel has been promoted during the pandemic. In this context, this project has been formulated to develop a homemade cleaning product, and to promote fruit recycling at home and in places where large amounts of this food type are discarded.
 The hypothesis of this article is that organic fruit waste contains sugars that produce bioethanol when oxidized, and that certain fruits (apples and quinces) are a rich source of pectin, which allows the alcohol obtained to be transformed into gel.
 The objective of the research was to obtain bioethanol and pectin from fruit in order to reduce organic waste from food markets and in the home, promoting maximum natural resource use by replacing the option of daily-use synthetic products.
 As a result, bioethanol and pectin were obtained from the organic waste of fruits such as apples and quinces, allowing homemade alcohol gel to be produced.
 In conclusion, the research hypothesis was proved correct, as bioethanol and pectin were produced from organic fruit waste via the fermentation and gelling processes.

Effects of membrane relaxation rate on performance of pilot-scale membrane aerated biofilm reactors treating domestic wastewater

The membranes of a Membrane Aerated Biofilm Reactor (MABR) function as bubble-less air diffusers and bio-carriers. Recent bench-scale experiments reported that the shape of membranes influenced the oxygen transfer and utilization rates, which in turn affected the pollutant removal performance of the MABR. In this study, two pilot-scale MABRs using multi-layer hollow fiber membranes with the relaxation rates of 0.1–1.8% (MABR 1) and 1.0–2.8% (MABR 2) were used for the treatment of organics and nitrogen in real medium-strength domestic wastewater. Higher-relaxation-rate membranes have loose and more curved fiber bunch that may allow biofilm to grow more easily and let air diffuse more efficiently. MABR 2 had achieved better performance than MABR 1 at 12- and 6-h Hydraulic Retention Time (HRT), with respectively 0.7–4.3%, 17.7–18.1%, and 5.5–9.0% higher removal efficiencies for Chemical Oxygen Demand (COD), Ammonia Nitrogen (NH4+), and Total Nitrogen (TN). The highest COD, NH4+, and TN removal efficiencies were 94.7%, 81.1%, and 57.1%, respectively, at 12 h HRT in MABR 2. The addition of Polyvinyl Alcohol (PVA) gel beads carrying denitrifying bacteria had enhanced the denitrification in both the reactors. Increments of 5.0–9.0% and 6.6–12.3% were reported for TN removal efficiencies of MABR 1 and 2 combined with PVA gel, sequentially.

A Novel Chemosensor for Selective Detection of L‐Arginine and L–Cysteine via Macroscopic Sol‐Gel Transition

AbstractTo develop chemosensors for biomolecule recognition, a multi stimuli responsive supramolecular gelator, [(E)‐4‐((4‐(benzyloxy)phenyl)diazenyl)benzaldehyde], comprised of azo and formyl units, was designed and synthesized from readily available starting materials. The gelator was found to be capable of forming gels in light alcohols and alcohol/water mixtures at low concentrations (0.7–1.5 g/100 mL). The gel rheological analyses showed the dominance of storage modulus (G′) values (ca 5000 Pa) within the range of analysis, confirming the gel stiffness. The xerogel scanning electron microscopy (SEM) studies showed a flake‐like pattern of thin sheets. Our investigations on the gelator sensing abilities revealed that, in addition to the photo‐responsive function due to the presence of azo moiety, its ethanol/water gel exhibited excellent ability to detect l‐arginine among 19 various amino acids, via gel to sol transition and colour change. Furthermore, the gelator could successfully recognize l‐cysteine among 19 amino acids, through macroscopic sol to gel transition and colour change of its alkaline methanolic solution. Moreover, the photo‐ and chemo‐responsive functions of the gelator were demonstrated as two combinational logic gates.

Near-neutral flexible zinc-air batteries with high power densities and long cycle life using chloride-based gel polymer electrolytes

In this work, to get improved battery performance via changing electrolyte formulations, a bifunctional catalyst, Ru0.6Sn0.4O2, and a polyvinyl alcohol gel polymer electrolyte (GPE) with a high water content (70%) are employed to fabricate flexible zinc-air batteries (FZABs). The optimal FZAB with a GPE containing 0.6 M ZnCl2 and 2.8 M NH4Cl reveals excellent power density of 12 mW cm−2 and prolonged cycle life over 100 h. Additionally, it can be charged and discharged under a bending angle of 90° at a large current density of 10 mA cm−2, 10 times higher than the best one reported, for more than 30 h, indicating excellent stability and flexibility. With a further increase or decrease in the ZnCl2 concentration in GPEs, the power performance or long-term cycling stability of FZABs declined, attributable to the low water content of GPEs and the degradation of zinc, respectively. We also, for the first time, report the origin of the decayed charge/discharge behavior of near-neutral FZABs, which can be ascribed to the precipitates of Zn(NH3)2Cl2 and Zn5(OH)8Cl2H2O on the zinc electrode to form a passivation layer. This study paves an avenue to further improve near-neutral FZABs.

Physical properties of polyvinyl alcohol (PVAL) gel materials as phantoms for mammography

This study evaluates the possibility of using polyvinyl alcohol (PVAL) composites as phantom material to simulate different densities of breast tissue for mammography based on their elastic properties. Three categories of PVAL gels were prepared by freezing and thawing 10 % water based PVAL (PVAL), ethanol and water based PVAL (PVAL/E) and a blend of PVAL with graphite powder (PVAL/G) solutions to mimic various breast densities. Young’s modulus (YM) of all samples was evaluated by puncture test using the texture analyser. The results recorded ranged from 0.93 to 4.79 kPa for all samples. The results indicate that the PVAL based phantoms examined could be used to simulate fatty and dense breast tissues based on the values of their densities and YM.

A Novel Method to Choose the Experimental Parameters in Large Amplitude Oscillatory Shear Rheology

Large Amplitude Oscillatory Shear (LAOS) rheology is a technique to analyze materials that are viscoelastic in nature. The raw values of stress and strain that were taken out from rheometer during the large amplitude oscillatory shear test are used in the constitutive models. The model parameters from the constitutive model are then analyzed on the materials being tested. Various test protocols and geometries will be used to analyze the materials of interest during LAOS rheological examination. The selection of test protocols and usage of geometry are less studied in testing various kinds of materials using LAOS. Cone and plate and parallel plate geometries are generally used for LAOS. The test protocols would be varying amplitude and varying frequencies. In the present work, quantification of relative performance of test protocols and geometry that have been used during the analysis of cross-linked poly vinyl alcohol hyaluronic acid (PVAHA) gels as material systems are studied using data envelopment analysis (DEA). The methodological approach using output oriented constant return to scale (CRS) and output oriented variable return to scale (VRS) are tested with the decision making units (DMU) as the geometry and test protocols used. These results are then combined with the Shannon's entropy to rank the efficient DMUs. Using Shannon's entropy combined with CRS and VRS, it is suggested that the use of parallel plate geometry with the test protocol of 0.5 rad/s and 50 frequency is best suitable for the cross-linked hyaluronic acid and poly vinyl alcohol gels examined.

Three-Dimensional hybrid structure loader type flexible supercapacitor based on Polyvinyl alcohol gel and Acetylene black

In order to overcome the structural drawbacks of layered electrodes in flexible supercapacitors, the construction of an electrode frame with high adaptability for the loading of different active materials makes the production of flexible supercapacitors simpler and more accurate. Herein, a novel loader type flexible supercapacitor with three-dimensional hybrid structure is built. In our design, the acetylene black and active material are enriched in the polyvinyl alcohol matrix, and the three-dimensional conductive network that can load different active material is formed. The active material can be selected on demand. The basic electrode (also a loader) formed by polyvinyl alcohol and acetylene black is an electronic conductor (∼1 Scm−1) with good electrochemical and mechanical performance. By loading active materials in this basic electrode, more powerful flexible electrodes can be built easily and accurately with the same steps according to the designed proportion. Electrodes constructed according to this method deliver nonnegligible surface capacity (e.g. 1.1 Fcm−2 in surface capacitance, polyaniline/carbon nanotube composite as active materials) with good response, rate performance, excellent durability (10000 times of charge-discharge), and good foldability (1000 times of folding). This pattern of carrier type electrodes provides a simple and universal strategy for manufacturing flexible supercapacitors.

EDUCATIONAL SCENARIOS OF PUBLIC HIGHER EDUCATION IN BRAZIL DESIGNED BY THE COVID-19 PANDEMIC

Brazilian Federal universities were directly affected by the COVID-19 pandemic, requiring educational changes and new teaching policies. The role of universities in society go far beyond the classroom, and with the changes caused by the COVID-19 pandemic, this role has intensified with social policies and actions developed thinking about the welfare of the community in which it is inserted. The objective of this study was to carry out a survey using a systematic literature review to identify the educational scenarios of public higher education in Brazil designed by the COVID-19 pandemic. The Methodi Ordinatio was used which ranked the main studies. The search was conducted in four bibliographic databases: Science Direct, Web of Science, Scopus, and Emerald. With the application of the systematic literature review, it was possible to find out that Brazilian federal universities played a key role, with actions in the community to which they belong, namely: activities carried out to clarify the community about the SARS-CoV-2 virus, information about prophylactic care, community care services, food distribution, diagnostics, development of applications and portals, research activities carried out by teachers for the development of vaccines, production, and manufacture of materials and equipment such as alcohol gel, personal protective equipment, cleaning materials and maintenance of hospital equipment, reinforcing the important role played by universities.

The impacts of the reopening of gyms in Porto Alegre from the manager's perspective

The article brought up reflections on some managerial aspects about the process of reopening the academies after the interruption of activities due to the sanitary measures of social distance due to the Covid-19 pandemic. The production aimed to understand the impact of reopening, after the need to close to meet the demands of health bodies due to the pandemic, on the management of gyms in Porto Alegre/RS. The data analysis method was based on a descriptive qualitative approach, through content analysis and relied on a collection of empirical data through interviews, news and official documents. The interviews were carried out with four managers, in person format and on online platforms and were transcribed to organize the analysis categories. The analysis explored three categories: operational, financial and relational. The empirical data surveys pointed to the difficulties related to the process of reopening the academies, in which at first arose from the need to maintain commercial activity and, for that, emergency actions such as teacher dismissals, reduction of collective classes and accumulation of functions of the manager were mentioned and a series of changes in the processes such as the availability of alcohol gel hygiene materials, newsletters, campaigns on social networks and compliance with health standards such as the use of masks, distancing, restriction on the number of students per schedule, in addition to the importance of establishing clear communication with those involved.

Behaviors of Water Molecules in Polyvinyl Alcohol Gel Amid Stretch and Temperature Changes: A Molecular Dynamics Study

Behaviors of Water Molecules in Polyvinyl Alcohol Gel Amid Stretch and Temperature Changes: A Molecular Dynamics Study

Rubber glove wastewater treatment by integrated fixed-film activated sludge using polyvinyl alcohol gel beads: effect of hydraulic retention time and percent of biomass carriers

Rubber glove wastewater treatment by integrated fixed-film activated sludge using polyvinyl alcohol gel beads: effect of hydraulic retention time and percent of biomass carriers

Synthesis of organic boron crosslinker for polyvinyl alcohol gel

In this article, borax was used as the prime agent, and the organic boron that cross-linked agent was synthesized using adding sodium tartrate. The synthesis response shapes were optimized using unmarried factor way. The temperature opposition and crosslinking time of the fracturing fluid were used as the appraisal standards to decide the organic boron. The cross-linking agent's optimal synthesis statuses were measured, and the chemical and forcible holdings of the fracturing fluid after cross-linking with the polyvinyl alcohol-based liquid were measured.

Flexible asymmetric supercapacitor with crosslinked polyacrylate containing double ions as solid electrolyte

In this study, flexible asymmetric supercapacitors are assembled with positive LiMn2O4/carbon cloth (CC) electrode and negative NaTi2(PO4)3/CC electrode. With the development of light-weight and flexible electronic devices, nowadays, solid-state supercapacitive devices have attracted great attention, in which the classic polymeric electrolytes such as polyvinyl alcohol and polyethylene oxide copolymers are widely used. To replace the non-ionic polyvinyl alcohol (PVA) gel and decrease internal resistance, a high conductive crosslinked polyacrylate (cPA) gel containing double ions is prepared. The structure of as-obtained LiMn2O4/CC, NaTi2(PO4)3/CC and cPA is thoroughly investigated. At current density of 0.2 mA/cm2, the flexible supercapacitor of LiMn2O4/CC = |cPA||NaTi2(PO4)3/CC shows a maximum capacitance of 84.80 mF per cm2, with a remarkable stability of 93.07% retention after 5000 charging and discharging cycles. Under the synergistic effects from the low-resistance cPA and the grouped NaTi2(PO4)3/LiMn2O4 in double-ion electrolyte, the fabricated solid supercapacitor displays a power density high as 249.96 Wh/kg (0.122 mW/cm2) at 0.4 A/g (0.2 mA/cm2) with the energy output of 36.80 Wh/kg (0.018 mWh/cm2).

Bifunctional Microwave-Assisted Molybdenum-Complex Carbon Sponge Production for Supercapacitor and Water-Splitting Applications.

The synthesis of dual-function molybdenum (Mo)-complex carbonous sponges is reported for elucidating their utilization as positive and negative electrodes in electrochemical devices and their applicability to the active oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in electrocatalytic devices. Molybdenum (Mo)-coordinated polyvinyl alcohol gel is converted into a porous Mo-complex nitrogen-rich carbonous sponge (MNCS) via microwave and low-temperature-annealing processes as a positive electrode. This MNCS was further thermally treated at a higher temperature to prepare a more carbonized Mo-complex N-doped carbon sponge (cMNCS) as a negative electrode. Both sponges were lightweight and porous and exhibited excellent specific capacitances of 562 F g-1 as a positive MNCS electrode and 937 F g-1 as a negative cMNCS electrode. The asymmetric supercapacitor assembled using them reveals a power density of 887.5 W kg-1 at an energy density of 36 Wh kg-1, in addition to a retention rate of >95% after 5000 cycles. We furthermore demonstrate the electrocatalytic capabilities of these materials with overpotentials of -170 and -220 mV for the HER and 1.70 and 1.53 V for the OER at a current density of 10 mA cm-2 using a water-splitting electrocatalyzer.