scholarly journals Radiofrequency surgery: Novel techniques in the treatment of ano-rectal disease

2006 ◽  
Vol 53 (2) ◽  
pp. 23-29 ◽  
Author(s):  
Pravin Gupta
Keyword(s):  
Cell Death ◽  
Wave Energy ◽  
High Frequency ◽  
Operative Time ◽  
Frictional Heating ◽  
Postoperative Recovery ◽  
Rectal Disease ◽  
Dual Frequency ◽  
Radiofrequency Surgery ◽  
Anal Papillae

Background: Radiofrequency surgery is a method of utilizing high frequency (3.8 to 4MHz) radio wave energy to incise, excise, or coagulate tissues. Radiofrequency (RF) is a relatively new modality that is being used for ano-rectal surgeries with increasing frequency. As the RF energy is applied, frictional heating of tissues results, with cell death occurring at temperatures between 60 and 1000 C. Objective- This paper discusses author?s clinical experience with radiofrequency for various ano-rectal pathologies namely hemorrhoids, anal fistula, anal polyps, sinuses and anal papillae. A Ellman dual frequency radiofrequency generator was used to carry out the procedures. This study is intended to be somewhat of a "how we do it" manual, explaining the principles of radiofrequency. Conclusion: Radiofrequency proctological procedures are simple to perform with many advantages over the more traditional techniques. The procedures take less operative time, the postoperative recovery is accelerated and the incidences of complications are negligible.

scholarly journals High-frequency radio wave electrocautery in modified Hotz operations for epiblepharon correction

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hyunkyu Lee ◽  
Jimin Youn ◽  
Sehyun Baek
Keyword(s):  
Radio Wave ◽  
Recurrence Rate ◽  
High Frequency ◽  
Operation Time ◽  
Lower Eyelid ◽  
Dual Frequency ◽  
Ocular Symptoms ◽  
Minimal Scarring ◽  
Degree Of Satisfaction

AbstractTo report the experience and advantageous effects of high-frequency radio wave electrocautery in modified Hotz operations for epiblepharon, We reviewed the records of all pediatric patients who underwent a modified Hotz operation with the use of high-frequency radio wave electrocautery (Ellman Surgitron Dual Frequency RF S5; Ellman International, Inc, Hewlett, NY) for epiblepharon between March 2016 and September 2019 at Korea University Guro Hospital. We evaluated the success rate, complications, recurrence rate and degree of satisfaction of our technique. Information from the medical records was collected, including demographics, ocular symptoms, severity of keratopathy, operation time, success/recurrence rate, and complications. 133 patients (98.52%) showed good correction of epiblepharon without complications or unpleasant cosmetic problems during 3 months of median follow-up period. Two patients (1.48%) showed recurrent corneociliary touch, but the degree was very mild and re-operation was not performed. One patient showed mild ectropion on his left lower eyelid, but the patient recovered well without operation. For complications, suture abscess and granulation were the most common, 3 cases in each, but all of those were temporary and resolved with conservative management. The approach with electrocautery for epiblepharon allows precise and fast incision of the lower eyelid, little bleeding, and minimal scarring. Surgical outcomes associated with the modified Hotz operation with electrocautery were consistent with previous studies.

Spatial distribution of high-frequency energy radiation on the fault of the 1995 Hyogo-Ken Nanbu, Japan, earthquake (MW 6.9) on the basis of the seismogram envelope inversion

1999 ◽  
Vol 89 (1) ◽  
pp. 22-35 ◽  
Author(s):  
Hisashi Nakahara ◽  
Haruo Sato ◽  
Masakazu Ohtake ◽  
Takeshi Nishimura
Keyword(s):  
Spatial Distribution ◽  
Wave Energy ◽  
High Frequency ◽  
Fault Plane ◽  
Time Window ◽  
Source Region ◽  
Inversion Method ◽  
S Wave ◽  
Energy Radiation ◽  
Initial Rupture

Abstract We studied the generation and propagation of high-frequency (above 1 Hz) S-wave energy from the 1995 Hyogo-Ken Nanbu (Kobe), Japan, earthquake (MW 6.9) by analyzing seismogram envelopes of the mainshock and aftershocks. We first investigated the propagation characteristics of high-frequency S-wave energy in the heterogeneous lithosphere around the source region. By applying the multiple lapse time window analysis method to aftershock records, we estimated two parameters that quantitatively characterize the heterogeneity of the medium: the total scattering coefficient and the intrinsic absorption of the medium for S waves. Observed envelopes of aftershocks were well reproduced by the envelope Green functions synthesized based on the radiative transfer theory with the obtained parameters. Next, we applied the envelope inversion method to 13 strong-motion records of the mainshock. We divided the mainshock fault plane of 49 × 21 km into 21 subfaults of 7 × 7 km square and estimated the spatial distribution of the high-frequency energy radiation on that plane. The average constant rupture velocity and the duration of energy radiation for each subfault were determined by grid searching to be 3.0 km/sec and 5.0 sec, respectively. Energy radiated from the whole fault plane was estimated as 4.9 × 1014 J for 1 to 2 Hz, 3.3 × 1014 J for 2 to 4 Hz, 1.5 × 1014 J for 4 to 8 Hz, 8.9 × 1012 J for 8 to 16 Hz, and 9.8 × 1014 J in all four frequency bands. We found that strong energy was mainly radiated from three regions on the mainshock fault plane: around the initial rupture point, near the surface at Awaji Island, and a shallow portion beneath Kobe. We interpret that energetic portions were associated with rupture acceleration, a fault surface break, and rupture termination, respectively.

scholarly journals Optimization of HF waves energy source for thermal treatment of building materials

2018 ◽  
Vol 251 ◽  
pp. 04010
Author(s):  
Irina Vorotyntseva
Keyword(s):  
Energy Source ◽  
Wave Energy ◽  
High Frequency ◽  
Energy Exchange ◽  
Building Materials ◽  
Functional Dependencies ◽  
Strength Change ◽  
Wave Heating ◽  
Characteristic Features ◽  
Hf Wave

Building materials processing with the help of HF waves demonstrates a great number of perspective advantages as compared to traditional heating methods. In order to upgrade the technology of HF wave heating there exist a need to optimize the HF waves sources that enable us to consider some characteristic features of the process to a greater extend. To solve the task of optimizing a HF wave energy source we use the methods of the optimal control theory. The optimization has been carried out based on the gradient method. As a result we have found some optimal functional dependencies that describe the laws strength change of an electrostatic and a high-frequency field. Established managements help considerably enhance the efficiency of the energy exchange. The calculations we have carried out show that the chosen method enables an efficient optimization of a HF wave energy source with different restrictions of the governing function.

Enhancement of docetaxel-treated MCF-7 cell death by 900-MHz radiation

2013 ◽  
Vol 8 (4) ◽  
pp. 357-365
Author(s):  
Marianna Trebuňová ◽  
Galina Laputková ◽  
Imrich Géci ◽  
Igor Andrašina ◽  
Ján Sabo
Keyword(s):  
Cell Culture ◽  
Cell Death ◽  
Electromagnetic Field ◽  
High Frequency ◽  
Input Power ◽  
Breast Adenocarcinoma ◽  
Human Breast ◽  
Human Breast Adenocarcinoma ◽  
High Frequency Electromagnetic Field ◽  
Mcf 7

AbstractThe aim of the study was to investigate the effect of high-frequency electromagnetic field of 900 MHz at 8 W input power on metabolic activity of human breast adenocarcinoma MCF-7 cells. With the aid of the colorimetric MTT assay, it was shown that there is significant change in cell culture survival exposed to docetaxel in field-free conditions in comparison with cells treated with docetaxel simultaneously exposed to high-frequency electromagnetic field.

scholarly journals Low to Very-High Frequency Ultrasound Biomicroscopy of Cell Death

2010 ◽  
Vol 16 (S2) ◽  
pp. 1110-1111
Author(s):  
GJ Czarnota
Keyword(s):  
Cell Death ◽  
High Frequency ◽  
Ultrasound Biomicroscopy ◽  
High Frequency Ultrasound ◽  
Very High Frequency ◽  
Very High ◽  
Frequency Ultrasound

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

scholarly journals High-frequency irreversible electroporation is an effective tumor ablation strategy that induces immunologic cell death and promotes systemic anti-tumor immunity

EBioMedicine ◽  
2019 ◽  
Vol 44 ◽  
pp. 112-125 ◽  
Author(s):  
Veronica M. Ringel-Scaia ◽  
Natalie Beitel-White ◽  
Melvin F. Lorenzo ◽  
Rebecca M. Brock ◽  
Kathleen E. Huie ◽  
...  
Keyword(s):  
Cell Death ◽  
Tumor Immunity ◽  
High Frequency ◽  
Irreversible Electroporation ◽  
Tumor Ablation

scholarly journals Wave energy attenuation in fields of colliding ice floes – Part 1: Discrete-element modelling of dissipation due to ice–water drag

2019 ◽  
Vol 13 (11) ◽  
pp. 2887-2900 ◽  
Author(s):  
Agnieszka Herman ◽  
Sukun Cheng ◽  
Hayley H. Shen
Keyword(s):  
Dispersion Relation ◽  
Wave Energy ◽  
High Frequency ◽  
Water Waves ◽  
Discrete Element ◽  
Unit Surface Area ◽  
Energy Propagation ◽  
Quadratic Drag ◽  
Ice Floes ◽  
Ice Water

Abstract. The energy of water waves propagating through sea ice is attenuated due to non-dissipative (scattering) and dissipative processes. The nature of those processes and their contribution to attenuation depends on wave characteristics and ice properties and is usually difficult (or impossible) to determine from limited observations available. Therefore, many aspects of relevant dissipation mechanisms remain poorly understood. In this work, a discrete-element model (DEM) is used to study one of those mechanisms: dissipation due to ice–water drag. The model consists of two coupled parts, a DEM simulating the surge motion and collisions of ice floes driven by waves and a wave module solving the wave energy transport equation with source terms computed based on phase-averaged DEM results. The wave energy attenuation is analysed analytically for a limiting case of a compact, horizontally confined ice cover. It is shown that the usage of a quadratic drag law leads to non-exponential attenuation of wave amplitude a with distance x, of the form a(x)=1/(αx+1/a0), with the attenuation rate α linearly proportional to the drag coefficient. The dependence of α on wave frequency ω varies with the dispersion relation used. For the open-water (OW) dispersion relation, α∼ω4. For the mass loading dispersion relation, suitable for ice covers composed of small floes, the increase in α with ω is much faster than in the OW case, leading to very fast elimination of high-frequency components from the wave energy spectrum. For elastic-plate dispersion relation, suitable for large floes or continuous ice, α∼ωm within the high-frequency tail, with m close to 2.0–2.5; i.e. dissipation is much slower than in the OW case. The coupled DEM–wave model predicts the existence of two zones: a relatively narrow area of very strong attenuation close to the ice edge, with energetic floe collisions and therefore high instantaneous ice–water velocities, and an inner zone where ice floes are in permanent or semi-permanent contact with each other, with attenuation rates close to those analysed theoretically. Dissipation in the collisional zone increases with an increasing restitution coefficient of the ice and with decreasing floe size. In effect, two factors contribute to strong attenuation in fields of small ice floes: lower wave energy propagation speeds and higher relative ice–water velocities due to larger accelerations of floes with smaller mass and more collisions per unit surface area.

High frequency irreversible electroporation (H-FIRE) as a novel method of targeted cell death.

2016 ◽  
Vol 34 (4_suppl) ◽  
pp. 277-277
Author(s):  
Imran A Siddiqui ◽  
Russell C. Kirks ◽  
Erin H Baker ◽  
Eduardo Latouche ◽  
Matt Dewitt ◽  
...  
Keyword(s):  
Cell Death ◽  
High Frequency ◽  
Irreversible Electroporation ◽  
Vital Signs ◽  
Cardiac Monitoring ◽  
Vascular Integrity ◽  
Cancer Cell Death ◽  
Novel Method ◽  
Vascular Structures ◽  
Cardiac Synchronization

277 Background: Irreversible electroporation unlike ablation is excellent in inducing cell death via apoptosis. It, however, has disadvantages of electrical conduction via cardiac and nervous tissue. This results in requiring cardiac monitoring and general anesthesia and paralytics while performing electroporation. We hypothesized a novel high-frequency IRE (H-FIRE) system employing ultra-short bipolar pulses would obviate the need for cardiac synchronization and paralytics while maintaining measurable effect on cell death. Methods: Female swine (55-65Kg) were used. Two H-FIRE electrodes were inserted into the liver (1.5-cm spacing). In the absence of paralytics H-FIRE pulses were delivered (2250V, 2-5-2 pulse configuration) at different on times (100 vs. 200μs) or number of pulses (100 vs. 300). Next electrodes were placed across major hepatic vascular structures and H-FIRE performed. At conclusion tissue was resected and analyzed histologically. Results: 24 H-FIREs were performed (mean ablation time 275 secs). No EKG abnormalities or changes in vital signs were measured during H-FIRE procedures. In 1/24 H-FIREs minor twitching of the rectus abdominis was recorded coinciding with pulse delivery. Histologically, tissues had effective electroporation as evidenced by cell death and caspase activity. Blinded scoring was performed for necrosis and apoptosis. Areas of cell death were predictable. No significant vascular damage or coagulated/thermally-desiccated blood was detected within major vessels following H-FIRE. Conclusions: H-FIRE is a novel way of liver electroporation. It produces predictable cell apoptosis without the requirement of paralytics and alteration of electrocardiographic signals as compared to traditional electroporation, while preserving underlying vascular integrity. Its application in cancer cell death needs to be further studied, but it has a potential for clinical use in targeting tumors with minimal morbidity and associated cardiac and neurologic side effects.

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