RESUMEN
Cold atmospheric plasma devices have shown high potential to be useful for different medical applications. In this study, it has been tried to develop and characterize a cold atmospheric spark plasma device that can be used safely as a tool for medical and aesthetic applications. The schematic of the device is presented in the paper, and the signals of each block are also tested. A special handpiece for this device is designed to make the device as safe as possible. The device's properties that can impose a risk to users' health have been under consideration. The device's electrical properties have been tested, and results show that the electrical current of the device is below the safety thresholds and can be used safely. The radiation power of the device also has been tested. It is shown that the time needed for the radiation power to reach the danger threshold is much longer than the treatment time. The device will not impose any risk regarding radiation from the UV spectrum. Optical emission spectroscopy is also used to investigate the neutral and charged species that are the by-products of electrical discharge. The presence of NOx and OH locally in the discharge can be helpful for various medical applications. This paper presents one of the first studies conducted to investigate the engineering aspect and the immunometry of the spark plasma that can be used in medicine and other purposes.
RESUMEN
Spent caustic is a used industrial caustic whose chemical content puts it in the special waste category. The disposal of this waste and the production of value-added products from it has attracted the attention of researchers not only to solve environmental problems but also to take advantage of its byproducts. This research has experimentally proved the transferred thermal plasma technology as a practical method feasible for the disposal of spent caustic. In this study, the applied voltage, electrical current, and feed rate are variable parameters, and others are kept constant. GC analysis showed H2 as the main product, which is environmentally beneficial. The percentage of hydrogen production of approximately 74% is a promising result, considering the difficulty of achieving such a high percentage of hydrogen.
RESUMEN
During the past decade, ever-increasing electromagnetic pollution has excited a global concern. A sustainable resource, facile experimental scenario, fascinating reflection loss (RL), and broad efficient bandwidth are the substantial factors that intrigue researchers. This research led to the achievement of a brilliant microwave-absorbing material by treating pampas as biomass. The carbon-based microfibers attained by biowaste were treated by plasma under diverse environments to amplify their microwave-absorbing features. Moreover, a pyrolysis scenario was performed to compare the results. The reductive processes were performed by H2 plasma and carbonization. However, the CO2 plasma was performed to regulate the heteroatoms and defects. Interestingly, polystyrene (PS) was applied as a microwave-absorbing matrix. The aromatic rings existing in the absorbing medium establish electrostatic interactions, elevating interfacial polarization, and physical characteristics of PS augment the practical applications of the final product. The manipulated biomasses were characterized by Raman, X-ray diffraction, energy-dispersive spectroscopy, field emission scanning electron microscopy, and diffuse reflection spectroscopy analyses. Eventually, the microwave-absorbing features were estimated by a vector network analyzer. The plasma-treated pampas under H2/Ar blended with PS gained a maximum RL of -90.65 dB at 8.79 GHz and an efficient bandwidth (RL ≤ -10 dB) of 4.24 GHz with a thickness of 3.20 mm; meanwhile, plasma treatment under CO2 led to a maximum RL of 97.99 dB at 14.92 GHz and an efficient bandwidth of 7.74 GHz with a 2.05 mm thickness. Particularly, the biomass plasmolyzed under Ar covered the entire X and Ku bands with a thickness of 2.10 mm. Notably, total shielding efficiencies of the treated bioinspired materials were up to ≈99%, desirable for practical applications.
RESUMEN
Slide electrification is the spontaneous separation of electric charges at the rear of water drops sliding over solid surfaces. This study delves into how surfaces treated with a low-pressure plasma impact water slide electrification. Ar, O2, and N2 plasma treatment reduced the drop charge and contact angles on glass, quartz, and SU-8 coated with 1H,1H,2H,2H-perfluoroctyltrichlorosilane (PFOTS), and polystyrene. Conversely, 64% higher drop charge was achieved using electrode-facing treatment in plasma chamber. Based on the zeta potential, Kelvin potential, and XPS measurements, the plasma effects were attributed to alterations of the topmost layer's chemistry, such as oxidation and etching, and superficially charge deposition. The surface top layer charges were less negative after electrode-facing and more negative after bulk plasma treatment. As a result, the zeta potential was less negative after electrode-facing and more negative after bulk plasma treatment. Although the fluorinated layer was applied after plasma activation, we observed a discernible impact of plasma-glass treatment on drop charging. Plasma surface modification offers a means to adjust drop charges: electrode-facing treatment of the fluorinated layer leads to an enhanced drop charge, while plasma treatment on the substrate prior to fluorination diminishes drop charges, all without affecting contact angles or surface roughness.
RESUMEN
Hydrogen sulfide (H2S) is known as a harmful pollutant for the environment and human health, and its emission control is a high priority. Non-thermal plasma is an effective technology in this field. In this study, for the first time, the performance of direct and indirect H2S plasma conversion methods was compared, optimized, and modeled with the CCD method. H2S was diluted in zero air, and the study investigated the effect of discharge power, relative humidity, total flow rate, initial H2S concentration, and their interactions. ANOVA results showed that the models for H2S conversion efficiency and energy yield were significant and efficient. The direct method achieved a maximum conversion efficiency of 56 % and energy yield of 3.43 g/kWh, while the indirect method produced 68 % conversion efficiency and 1.59 g/kWh energy yield. According to the process optimization results, the direct conversion method is more optimal than the indirect conversion method due to the presence of active species and high-energy electrons in the plasma treatment, and it is a better choice if there are suitable working conditions.
RESUMEN
Metal-organic frameworks (MOFs) as carbon dioxide adsorption in combination with metal oxides have shown catalyst application in CO2 conversion. Herein, the MgO/HKUST-1 catalyst is synthesized to direct conversion of CO2 upon dilution by argon in a cylindrical dielectric barrier discharge (DBD) reactor. A water-cooling circulation adjusts the reactor temperature, and aluminum powder is used as a high-voltage electrode. The effect of the discharge power, feed flow rate, CO2 fraction, and their interaction in plasma and plasma catalyst method on CO2 conversion (R1), effective CO2 conversion (R2), and energy efficiency (R3) is evaluated by central composite design (CCD) based on response surface methodology. The Analysis of Variance (ANOVA) results demonstrate that the quadratic regression model describes CO2 conversion and effective CO2 conversion, and the reduced cubic model describes energy efficiency. The results indicate that the method (plasma, plasma catalyst) and discharge power on R1 and R2 have a considerable effect. Also, the method and CO2 fraction on R3 have the greatest impact, respectively. In the plasma and plasma catalyst method maximum CO2 conversion is 12.3% and 20.5% at a feed flow rate of 80 ml/min, CO2 fraction of 50%, and discharge power of 74 W.
RESUMEN
This study used the FEDBD plasma device for skin rejuvenation in animal samples. There were two groups of six male Wistar rats. Before starting the treatment, immediately after the treatment, the fourth week, and the tenth week of follow-up, biometric tests were performed, including moisture level, evaporation from the skin surface, erythema and melanin, skin elasticity and firmness with an MPA9 device and cutometer. The thickness and density of the epidermis and dermis, an essential indicator in rejuvenation, were evaluated with a skin ultrasound device. Also, the level of oxygen, perfusion, and interstitial water (edema) was checked using a Tivita tissue hyperspectral camera at a depth of 6 mm of the skin.
RESUMEN
Butter is a perishable food, and its microbial deterioration occurs in refrigeration conditions, leading to a reduction in shelf life and a loss of sensory properties. This study aimed to investigate the effect of chia seed extract (CSE) on the microbial and sensory properties of pasteurized sweet cream butter at 2°C. Ethanolic extract of chia seeds was prepared and added to the butter samples in concentrations of 0.05%, 0.1%, 0.25%, and 0.5% (v/w), and its effects on microbiological and sensory quality were evaluated at 15-day intervals during 60-day refrigerated storage. The results indicated that the addition of 0.25% and 0.5% CSE to butter treatments decreased total viable counts by 0.25-0.6 log CFU/g, total psychrotrophic counts by 1-1.5 log CFU/g, and coliform counts by 3-4 log CFU/g compared to the control sample on days 45 and 60 of storage. Moreover, concentrations of 0.1%-0.5% CSE reduced mold and yeast counts by 1.5-2.6 log CFU/g on days 30-60 of storage compared to the control sample. Escherichia coli and Staphylococcus aureus were not detected in any samples during storage. CSE had a significant effect on the sensory properties (except for aroma) of the butter samples during the 60-day storage. The best color, flavor, and overall acceptance scores were assigned to the treatments containing 0.1%-0.5% CSE compared to the control sample. It could be concluded that adding 0.1% and 0.25% CSE to refrigerated and pasteurized butter can retard microbial spoilage and improve its sensory properties at the same time.
RESUMEN
BACKGROUND: Seborrheic keratoses (SK) is a benign epithelial skin tumor and plasma exeresis is a new technique. AIMS: To compare the efficacy and safety of plasma exeresis and cryotherapy for treating SK. METHODS: This study is a randomized controlled trial (RCT). One side of each patient was randomly treated with plasma exeresis (peak-to-peak voltage of 3.44 kV and a frequency of 62.5 kHz) and the other side with cryotherapy. RESULTS: Thirty-five males were enrolled. At week 3, 37.1 % (N = 13) of lesions treated by plasma exeresis were clear, which was higher than those treated by cryotherapy 17.1% (N = 6). However, this difference was not significant (p-value: 0.06). At week 6, 16 (57.1 %) out of 28 remaining lesions, treated by plasma exeresis were clear, which was significantly higher (p-value: 0.005) than those completely cleared by cryotherapy in 6 out of 29 remaining lesions (20.7%). The mean physician assessment scale score was significantly reduced in both groups in the second follow-up (plasma group first follow-up 0.91 ± 0.89 vs. second follow-up 0.5 ± 0.64 and p-value: 0.0031; cryo group first follow-up 1.4 ± 0.84 vs. second follow-up 1.1 ± 0.72 and p-value: 0.0002). Regarding side effects, no significant difference was seen (p = 0.438). The most common complications in the plasma and cryotherapy groups were erythema (10/19, 52.63%) and hypo pigmentation (5/13, 38.46%). CONCLUSIONS: Both cryotherapy and plasma exeresis are effective. We observed a significantly higher cleared lesions treated with plasma exeresis in 6 weeks and after two sessions.
Asunto(s)
Queratosis Seborreica , Neoplasias Cutáneas , Masculino , Humanos , Queratosis Seborreica/terapia , Crioterapia/efectos adversos , PigmentaciónRESUMEN
Cold atmospheric plasma has been developed and utilized as a novel technique for skin rejuvenation because of its various effects on cells and living things. This study investigated the accuracy of this claim and any possible side effects of using spark plasma to rejuvenate skin. The present work is the first quantitative investigation using animal models. 12 Wistar rats were divided into two groups for this investigation. To compare the skin's natural process with the treated skin, the first group underwent a single session of plasma therapy, while the second group served as the control group. The back of the necks of the samples was shaved for 20 cm. Before beginning treatment, the MPA9 multifunctional skin tester was used to determine the melanin index, erythema index, and transepidermal water loss (TEWL). The skin's thickness and density were assessed using sonography, and its elasticity index was calculated using a Cutometer. The samples were exposed to plasma radiation in the designated area (in a triangular pattern). The abovementioned signs were examined immediately after the following therapy and at the weekly appointment 2-4 weeks later. Optical spectroscopy was also used to demonstrate the presence of active species. In this study, we found that a plasma spark therapy session significantly boosts skin elasticity, and the ultrasound results revealed a significantly increased skin thickness and density. The plasma increased the amount of skin surface evaporation, erythema, and melanin immediately following the treatment. However, 4 weeks later, it recovered to its former state and did not differ significantly from before the therapy.
Asunto(s)
Melaninas , Piel , Animales , Ratas , Ratas Wistar , Eritema/etiología , Elasticidad , BiometríaRESUMEN
BACKGROUND: Intrathecal drug delivery has a significant role in pain management and central nervous system (CNS) disease therapeutics. A fluid-physics based tool to assist clinicians in choosing specific drug doses to the spine or brain may help improve treatment schedules. METHODS: This study applied computational fluid dynamics (CFD) and in vitro model verification to assess intrathecal drug delivery in an anatomically idealized model of the human CSF system with key anatomic features of the CNS. Key parameters analyzed included the role of (a) injection location including lumbar puncture (LP), cisterna magna (CM) and intracerebroventricular (ICV), (b) LP injection rate, injection volume, and flush volume, (c) physiologic factors including cardiac-induced and deep respiration-induced CSF stroke volume increase. Simulations were conducted for 3-h post-injection and used to quantify spatial-temporal tracer concentration, regional area under the curve (AUC), time to maximum concentration (Tmax), and maximum concentration (Cmax), for each case. RESULTS: CM and ICV increased AUC to brain regions by ~ 2 logs compared to all other simulations. A 3X increase in bolus volume and addition of a 5 mL flush both increased intracranial AUC to the brain up to 2X compared to a baseline 5 mL LP injection. In contrast, a 5X increase in bolus rate (25 mL/min) did not improve tracer exposure to the brain. An increase in cardiac and respiratory CSF movement improved tracer spread to the brain, basal cistern, and cerebellum up to ~ 2 logs compared to the baseline LP injection. CONCLUSION: The computational modeling approach provides ability to conduct in silico trials representative of CSF injection protocols. Taken together, the findings indicate a strong potential for delivery protocols to be optimized to reach a target region(s) of the spine and/or brain with a needed therapeutic dose. Parametric modification of bolus rate/volume and flush volume was found to have impact on tracer distribution; albeit to a smaller degree than injection location, with CM and ICV injections resulting in greater therapeutic dose to brain regions compared to LP. CSF stroke volume and frequency both played an important role and may potentially have a greater impact than the modest changes in LP injection protocols analyzed such as bolus rate, volume, and flush.
Asunto(s)
Líquido Cefalorraquídeo , Cisterna Magna , Sistemas de Liberación de Medicamentos , Inyecciones Intraventriculares , Inyecciones Espinales , Modelos Teóricos , Simulación por Computador , Humanos , HidrodinámicaRESUMEN
A detailed understanding of the CSF dynamics is needed for design and optimization of intrathecal drug delivery devices, drugs, and protocols. Preclinical research using large-animal models is important to help define drug pharmacokinetics-pharmacodynamics and safety. In this study, we investigated the impact of catheter implantation in the sub-dural space on CSF flow dynamics in Cynomolgus monkeys. Magnetic resonance imaging (MRI) was performed before and after catheter implantation to quantify the differences based on catheter placement location in the cervical compared to the lumbar spine. Several geometric and hydrodynamic parameters were calculated based on the 3D segmentation and flow analysis. Hagen-Poiseuille equation was used to investigate the impact of catheter implantation on flow reduction and hydraulic resistance. A linear mixed-effects model was used in this study to investigate if there was a statistically significant difference between cervical and lumbar implantation, or between two MRI time points. Results showed that geometric parameters did not change statistically across MRI measurement time points and did not depend on catheter location. However, catheter insertion did have a significant impact on the hydrodynamic parameters and the effect was greater with cervical implantation compared to lumbar implantation. CSF flow rate decreased up to 55% with the catheter located in the cervical region. The maximum flow rate reduction in the lumbar implantation group was 21%. Overall, lumbar catheter implantation disrupted CSF dynamics to a lesser degree than cervical catheter implantation and this effect remained up to two weeks post-catheter implantation in Cynomolgus monkeys.
Asunto(s)
Cateterismo , Líquido Cefalorraquídeo/metabolismo , Hidrodinámica , Animales , Macaca fascicularis , Imagen por Resonancia Magnética , MasculinoRESUMEN
BACKGROUND: Blood removal from cerebrospinal fluid (CSF) in post-subarachnoid hemorrhage patients may reduce the risk of related secondary brain injury. We formulated a computational fluid dynamics (CFD) model to investigate the impact of a dual-lumen catheter-based CSF filtration system, called Neurapheresis™ therapy, on blood removal from CSF compared to lumbar drain. METHODS: A subject-specific multiphase CFD model of CSF system-wide solute transport was constructed based on MRI measurements. The Neurapheresis catheter geometry was added to the model within the spinal subarachnoid space (SAS). Neurapheresis flow aspiration and return rate was 2.0 and 1.8 mL/min, versus 0.2 mL/min drainage for lumbar drain. Blood was modeled as a bulk fluid phase within CSF with a 10% initial tracer concentration and identical viscosity and density as CSF. Subject-specific oscillatory CSF flow was applied at the model inlet. The dura and spinal cord geometry were considered to be stationary. Spatial-temporal tracer concentration was quantified based on time-average steady-streaming velocities throughout the domain under Neurapheresis therapy and lumbar drain. To help verify CFD results, an optically clear in vitro CSF model was constructed with fluorescein used as a blood surrogate. Quantitative comparison of numerical and in vitro results was performed by linear regression of spatial-temporal tracer concentration over 24-h. RESULTS: After 24-h, tracer concentration was reduced to 4.9% under Neurapheresis therapy compared to 6.5% under lumbar drain. Tracer clearance was most rapid between the catheter aspiration and return ports. Neurapheresis therapy was found to have a greater impact on steady-streaming compared to lumbar drain. Steady-streaming in the cranial SAS was ~ 50× smaller than in the spinal SAS for both cases. CFD results were strongly correlated with the in vitro spatial-temporal tracer concentration under Neurapheresis therapy (R2 = 0.89 with + 2.13% and - 1.93% tracer concentration confidence interval). CONCLUSION: A subject-specific CFD model of CSF system-wide solute transport was used to investigate the impact of Neurapheresis therapy on tracer removal from CSF compared to lumbar drain over a 24-h period. Neurapheresis therapy was found to substantially increase tracer clearance compared to lumbar drain. The multiphase CFD results were verified by in vitro fluorescein tracer experiments.
Asunto(s)
Eliminación de Componentes Sanguíneos/métodos , Sangre , Catéteres , Líquido Cefalorraquídeo , Drenaje , Diseño de Equipo , Modelos Biológicos , Punción Espinal , Hemorragia Subaracnoidea/terapia , Adulto , Eliminación de Componentes Sanguíneos/instrumentación , Femenino , Humanos , Hidrodinámica , Imagen por Resonancia Magnética , Adulto JovenRESUMEN
BACKGROUND: Developing novel therapeutic agents to treat amyotrophic lateral sclerosis (ALS) has been difficult due to multifactorial pathophysiologic processes at work. Intrathecal drug administration shows promise due to close proximity of cerebrospinal fluid (CSF) to affected tissues. Development of effective intrathecal pharmaceuticals will rely on accurate models of how drugs are dispersed in the CSF. Therefore, a method to quantify these dynamics and a characterization of differences across disease states is needed. METHODS: Complete intrathecal 3D CSF geometry and CSF flow velocities at six axial locations in the spinal canal were collected by T2-weighted and phase-contrast MRI, respectively. Scans were completed for eight people with ALS and ten healthy controls. Manual segmentation of the spinal subarachnoid space was performed and coupled with an interpolated model of CSF flow within the spinal canal. Geometric and hydrodynamic parameters were then generated at 1 mm slice intervals along the entire spine. Temporal analysis of the waveform spectral content and feature points was also completed. RESULTS: Comparison of ALS and control groups revealed a reduction in CSF flow magnitude and increased flow propagation velocities in the ALS cohort. Other differences in spectral harmonic content and geometric comparisons may support an overall decrease in intrathecal compliance in the ALS group. Notably, there was a high degree of variability between cases, with one ALS patient displaying nearly zero CSF flow along the entire spinal canal. CONCLUSION: While our sample size limits statistical confidence about the differences observed in this study, it was possible to measure and quantify inter-individual and cohort variability in a non-invasive manner. Our study also shows the potential for MRI based measurements of CSF geometry and flow to provide information about the hydrodynamic environment of the spinal subarachnoid space. These dynamics may be studied further to understand the behavior of CSF solute transport in healthy and diseased states.
Asunto(s)
Esclerosis Amiotrófica Lateral/líquido cefalorraquídeo , Esclerosis Amiotrófica Lateral/diagnóstico por imagen , Líquido Cefalorraquídeo/diagnóstico por imagen , Imagen por Resonancia Magnética , Espacio Subaracnoideo/diagnóstico por imagen , Adulto , Líquido Cefalorraquídeo/fisiología , Simulación por Computador , Humanos , Hidrodinámica , Imagen por Resonancia Magnética/métodos , Masculino , Modelos Biológicos , Canal Medular/fisiologíaRESUMEN
It has been hypothesized that early and rapid filtration of blood from cerebrospinal fluid (CSF) in postsubarachnoid hemorrhage patients may reduce hospital stay and related adverse events. In this study, we formulated a subject-specific computational fluid dynamics (CFD) model to parametrically investigate the impact of a novel dual-lumen catheter-based CSF filtration system, the Neurapheresis™ system (Minnetronix Neuro, Inc., St. Paul, MN), on intrathecal CSF dynamics. The operating principle of this system is to remove CSF from one location along the spine (aspiration port), externally filter the CSF routing the retentate to a waste bag, and return permeate (uncontaminated CSF) to another location along the spine (return port). The CFD model allowed parametric simulation of how the Neurapheresis system impacts intrathecal CSF velocities and steady-steady streaming under various Neurapheresis flow settings ranging from 0.5 to 2.0 ml/min and with a constant retentate removal rate of 0.2 ml/min simulation of the Neurapheresis system were compared to a lumbar drain simulation with a typical CSF removal rate setting of 0.2 ml/min. Results showed that the Neurapheresis system at a maximum flow of 2.0 ml/min increased average steady streaming CSF velocity 2× in comparison to lumbar drain (0.190 ± 0.133 versus 0.093 ± 0.107 mm/s, respectively). This affect was localized to the region within the Neurapheresis flow loop. The mean velocities introduced by the flow loop were relatively small in comparison to normal cardiac-induced CSF velocities.
Asunto(s)
Simulación por Computador , Hidrodinámica , Modelos Biológicos , Columna VertebralRESUMEN
INTRODUCTION: This study evaluated and compared the antibacterial effect of plasma and photodynamic therapy (PDT) in root canals infected with Enterococcus faecalis. METHODS: One hundred single-rooted extracted human teeth (no treatment) were selected and sterilized. Root canals of teeth were prepared with the crown-down technique and contaminated with Enterococcus faecalis after sterilization, and incubated for one week. To investigate the effect of disinfection, 60 specimens were randomly selected for three disinfection groups: He and He/O2 plasma (n = 20) in 5-s groups (control, 2, 4, 6 and 8 min treatments) and PDT (n = 20) in 2-s groups (control and PDT treatment). Next, for comparison, 40 remaining teeth were divided into four groups: control, 8 min He plasma, 8 min He/O2, and PDT. Results of antibacterial action were reported by CFU/mL analysis and the structural changes of biofilm were evaluated by SEM. RESULTS: All groups showed a significant reduction of bacteria after treatment, and He/O2 plasma was more effective against E. faecalis, followed by PDT and He plasma respectively, further confirmed by SEM. CONCLUSION: He/O2 plasma is a strong sterilization method against E. faecalis biofilm and can, therefore, be an effective therapy in endodontics.
Asunto(s)
Cavidad Pulpar/microbiología , Desinfección/métodos , Enterococcus faecalis/efectos de los fármacos , Fotoquimioterapia/métodos , Gases em Plasma , Helio , Humanos , Técnicas In Vitro , OxígenoRESUMEN
Recent advancements have been made toward understanding the diagnostic and therapeutic potential of cerebrospinal fluid (CSF) and related hydrodynamics. Increased understanding of CSF dynamics may lead to improved detection of central nervous system (CNS) diseases and optimized delivery of CSF based CNS therapeutics, with many proposed therapeutics hoping to successfully treat or cure debilitating neurological conditions. Before significant strides can be made toward the research and development of interventions designed for human use, additional research must be carried out with representative subjects such as non-human primates (NHP). This study presents a geometric and hydrodynamic characterization of CSF in eight cynomolgus monkeys (Macaca fascicularis) at baseline and two-week follow-up. Results showed that CSF flow along the entire spine was laminar with a Reynolds number ranging up to 80 and average Womersley number ranging from 4.1-7.7. Maximum CSF flow rate occurred ~25 mm caudal to the foramen magnum. Peak CSF flow rate ranged from 0.3-0.6 ml/s at the C3-C4 level. Geometric analysis indicated that average intrathecal CSF volume below the foramen magnum was 7.4 ml. The average surface area of the spinal cord and dura was 44.7 and 66.7 cm2 respectively. Subarachnoid space cross-sectional area and hydraulic diameter ranged from 7-75 mm2 and 2-3.7 mm, respectively. Stroke volume had the greatest value of 0.14 ml at an axial location corresponding to C3-C4.
Asunto(s)
Enfermedades del Sistema Nervioso Central/diagnóstico por imagen , Líquido Cefalorraquídeo/diagnóstico por imagen , Imagen por Resonancia Magnética , Columna Vertebral/diagnóstico por imagen , Animales , Femenino , Hidrodinámica , Macaca fascicularis , MasculinoRESUMEN
A dielectric barrier discharge system with a discharging zone where degradation processes happen is designed to remove 4-chlorophenol from water. The removal of 4-chlorophenol was influenced by the processing parameters such as gas flow rate, flow ratio of oxygen and argon, applied voltage and total applied power. Increasing the power or gas flow rates within a certain range enhanced the removal efficiency. 99% of 4-chlorophenol was removed in 6.5 min at reactor's efficient point which is set by adjusting the flow ratio of introduced gases and voltage. The removal percent was about 95% at 5 min of non-thermal plasma treatment with peak voltage of 10 kV and oxygen and argon flow rate of 20 SCCM and 200 SCCM respectively. Then by adjusting the flow ratios in order to find the optimum point. At this point the efficiency reached its peak due to excessive introduction oxygen gas which results in production of more oxidative agents. HPLC and GC-MS analysis have been carried out in order to investigate the by-products of degradation process. After 6.5 min of treatment at efficient point of degradation reactor, a 64% decrease in COD index has been indicated.
RESUMEN
Cerebrospinal fluid (CSF) dynamics are thought to play a vital role in central nervous system (CNS) physiology. The objective of this study was to investigate the impact of spinal cord (SC) nerve roots (NR) on CSF dynamics. A subject-specific computational fluid dynamics (CFD) model of the complete spinal subarachnoid space (SSS) with and without anatomically realistic NR and nonuniform moving dura wall deformation was constructed. This CFD model allowed detailed investigation of the impact of NR on CSF velocities that is not possible in vivo using magnetic resonance imaging (MRI) or other noninvasive imaging methods. Results showed that NR altered CSF dynamics in terms of velocity field, steady-streaming, and vortical structures. Vortices occurred in the cervical spine around NR during CSF flow reversal. The magnitude of steady-streaming CSF flow increased with NR, in particular within the cervical spine. This increase was located axially upstream and downstream of NR due to the interface of adjacent vortices that formed around NR.
Asunto(s)
Líquido Cefalorraquídeo/metabolismo , Hidrodinámica , Modelos Anatómicos , Raíces Nerviosas Espinales/anatomía & histología , Raíces Nerviosas Espinales/fisiología , Femenino , Humanos , Imagen por Resonancia Magnética , Modelación Específica para el Paciente , Raíces Nerviosas Espinales/diagnóstico por imagen , Espacio Subaracnoideo/anatomía & histología , Espacio Subaracnoideo/diagnóstico por imagen , Espacio Subaracnoideo/fisiología , Adulto JovenRESUMEN
According to high incidence and prevalence of pressure ulcers worldwide, the purpose of this study is using of non-thermal atmospheric plasma as a novel therapy for pressure ulcers. Cold plasma was produced by applying a high-voltage (5 kV) and high-frequency (25 kHz), to helium gas. Under general anesthesia and sterile conditions, two circular magnets were used to create pressure ulcers on the dorsal skin of adult rats. The wounds were divided randomly into control and plasma-treated groups. Animals in the plasma-treated group received plasma radiation for 5 days, each day 3 times and every time 60 s. Mechanical assays were performed to determine plasma effects on the mechanical strength of the repaired tissue. The results showed that mechanical strength of repaired wound in the plasma-treated group was significantly higher than that in the control group (p < 0.05). In addition, evidence from histological studies indicates a significantly accelerated wound re-epithelialization in comparison with the control group; angiogenesis and fibrosis (collagen synthesis) were also significantly increased and the inflammation phase of wound healing was shorter in the plasma-treated group. The plasma treatment also resulted in significant wound contraction and acceleration of wound healing. The findings of present study indicate the effects of cold plasma on pressure ulcer treatment.