21 CFR 886.4100 - Radiofrequency electrosurgical cautery apparatus.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiofrequency electrosurgical cautery apparatus... SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4100 Radiofrequency electrosurgical cautery apparatus. (a) Identification. A radiofrequency electrosurgical cautery apparatus is an AC...

Temperature-controlled irrigated tip radiofrequency catheter ablation

DEFF Research Database (Denmark)

Petersen, H H; Chen, X; Pietersen, Adrian

1998-01-01

INTRODUCTION: In patients with ventricular tachycardias due to structural heart disease, catheter ablation cures radiofrequency ablation. Irrigated tip radiofrequency ablation using power control and high infusion rates enlarges lesion......: We conclude that temperature-controlled radiofrequency ablation with irrigated tip catheters using low target temperature and low infusion rate enlarges lesion size without increasing the incidence of cratering and reduces coagulum formation of the tip....

Radiofrequency Ablation of Hepatic Cysts : Case Report

International Nuclear Information System (INIS)

Lee, Ye Ri; Kim, Pyo Nyun

2005-01-01

Radiofrequency ablation has been frequently performed on intra-hepatic solid tumor, namely, hepatocellular carcinoma, metastatic tumor and cholangio carcinoma, for take the cure. But, the reports of radiofrequency ablation for intrahepatic simple cysts are few. In vitro experiment of animal and in vivo treatment for intrahepatic cysts of human had been reported in rare cases. We report 4 cases of radiofrequency ablation for symptomatic intrahepatic cysts

Ablation of liver metastases by radiofrequency

International Nuclear Information System (INIS)

Baere, T. de

2012-01-01

Radiofrequency is a thermal ablative technique that is most often used percuteanously under image guidance. Thermal damage is obtained through frictional heating of a high frequency current. The maximal volume of destruction obtained in one radiofrequency delivery is around 4 cm and consequently, best indication for treatment are tumours below 3 cm. When compared, radiofrequency and surgical removal for tumours below 25 mm in diameter demonstrated a rate of incomplete resection/ablation of 6% and 7.3% respectively. Median survival after the first radiofrequency of a liver metastasis of CRC is reported to be 24 to 52 months with a 5 years overall survival of 18 to 44%. The median overall survival increases from 22 to 48 months depending on the use of radiofrequency ablation as rescue treatment after failure of others, or as a first line treatment. For patients with a single tumour, less than 4 cm, the survival rates at 1, 3, and 5 years are respectively 97%, 84% and 40%, with a median survival of 50 months. Follow-up imaging requires to use contrast-enhanced CT or MRI, looking for local recurrences evidenced by local foci of enhancement at the periphery of the ablation zone. (author)

47 CFR 1.1310 - Radiofrequency radiation exposure limits.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Radiofrequency radiation exposure limits. 1... Procedures Implementing the National Environmental Policy Act of 1969 § 1.1310 Radiofrequency radiation... exposure to radiofrequency (RF) radiation as specified in § 1.1307(b), except in the case of portable...

Saline-enhanced radiofrequency electrocoagulation in bovine liver

Energy Technology Data Exchange (ETDEWEB)

Shin, Hong Seop; Oh, Joo Hyeong; Yoon, Yup; Kim, Hyun Cheol; Ko, Young Tae; Choi, Woo Suk; Lim, Joo Won; Kim, Eui Jong [Kyunghee Univ. Hospital, Seoul (Korea, Republic of)

1997-08-01

To determine the effectiveness of saline-enhanced radiofrequency electrocoagulation in bovine liver tissue Saline-enhanced radiofrequency electrocoagulation (group I), hot saline injection induced by radiofrequency electrocoagulation (group II), and radiofrequency electrocoagulation (group III) were performed in ex vivo bovine liver. Radiofrequency power was 100 and 200 watts, and current was applied for 10, 20, and 30 seconds. Tissue was histopathologically examined for thermal injury. The largest diameter of thermal injury was about 41.0 mm in group I, 12.3 mm in group II and 9.3 mm in group III. The mean diameter of the injury increased with higher wattage in group I and II and with longer procedure time in group I (p<0.05). At corresponding wattage and times, group I showed a larger diameter of thermal injury and more increase in than group II or III (p<0.05). The degree of carbonization was more severe in group III than in groups I and II. Grossly, thermal injury showed a well-defined, relatively spherical configuration without extension along parenchymal interstitium. In an animal model, saline-enhanced radiofrequency electrocoagulation may effectively induce thermal injury, and may thus be another effective tool for use in the treatment of hepatic tumors. Further clinical experience is needed.

Saline-enhanced radiofrequency electrocoagulation in bovine liver

International Nuclear Information System (INIS)

Shin, Hong Seop; Oh, Joo Hyeong; Yoon, Yup; Kim, Hyun Cheol; Ko, Young Tae; Choi, Woo Suk; Lim, Joo Won; Kim, Eui Jong

1997-01-01

To determine the effectiveness of saline-enhanced radiofrequency electrocoagulation in bovine liver tissue Saline-enhanced radiofrequency electrocoagulation (group I), hot saline injection induced by radiofrequency electrocoagulation (group II), and radiofrequency electrocoagulation (group III) were performed in ex vivo bovine liver. Radiofrequency power was 100 and 200 watts, and current was applied for 10, 20, and 30 seconds. Tissue was histopathologically examined for thermal injury. The largest diameter of thermal injury was about 41.0 mm in group I, 12.3 mm in group II and 9.3 mm in group III. The mean diameter of the injury increased with higher wattage in group I and II and with longer procedure time in group I (p<0.05). At corresponding wattage and times, group I showed a larger diameter of thermal injury and more increase in than group II or III (p<0.05). The degree of carbonization was more severe in group III than in groups I and II. Grossly, thermal injury showed a well-defined, relatively spherical configuration without extension along parenchymal interstitium. In an animal model, saline-enhanced radiofrequency electrocoagulation may effectively induce thermal injury, and may thus be another effective tool for use in the treatment of hepatic tumors. Further clinical experience is needed

Image-guided radiofrequency ablation of renal cell carcinoma

International Nuclear Information System (INIS)

Boss, Andreas; Clasen, Stephan; Pereira, Philippe L.; Kuczyk, Markus; Schick, Fritz

2007-01-01

The incidence of renal cell carcinoma is rising with the increased number of incidental detection of small tumours. During the past few years, percutaneous imaging-guided radiofrequency ablation has evolved as a minimally invasive treatment of small unresectable renal tumours offering reduced patient morbidity and overall health care costs. In radiofrequency ablation, thermal energy is deposited into a targeted tumour by means of a radiofrequency applicator. In recent studies, radiofrequency ablation was shown to be an effective and safe modality for local destruction of renal cell carcinoma. Radiofrequency applicator navigation can be performed via ultrasound, computed tomography or magnetic resonance guidance; however, ultrasound seems less favourable because of the absence of monitoring capabilities during ablation. On-line monitoring of treatment outcome can only be performed with magnetic resonance imaging giving the possibility of eventual applicator repositioning to ablate visible residual tumour tissue. Long-term follow-up is crucial to assess completeness of tumour ablation. New developments in ablation technology and radiological equipment will further increase the indication field for radiofrequency ablation of renal cell carcinoma. Altogether, radiofrequency ablation seems to be a promising new modality for the minimally invasive treatment of renal cell carcinoma, which was demonstrated to exhibit high short-term effectiveness. (orig.)

New-generation radiofrequency technology.

Science.gov (United States)

Krueger, Nils; Sadick, Neil S

2013-01-01

Radiofrequency (RF) technology has become a standard treatment in aesthetic medicine with many indications due to its versatility, efficacy, and safety. It is used worldwide for cellulite reduction; acne scar revision; and treatment of hypertrophic scars and keloids, rosacea, and inflammatory acne in all skin types. However, the most common indication for RF technology is the nonablative tightening of tissue to improve skin laxity and reduce wrinkles. Radiofrequency devices are classified as unipolar, bipolar, or multipolar depending on the number of electrodes used. Additional modalities include fractional RF; sublative RF; phase-controlled RF; and combination RF therapies that apply light, massage, or pulsed electromagnetic fields (PEMFs). This article reviews studies and case series on these devices. Radiofrequency technology for aesthetic medicine has seen rapid advancements since it was used for skin tightening in 2003. Future developments will continue to keep RF technology at the forefront of the dermatologist's armamentarium for skin tightening and rejuvenation.

78 FR 25916 - Authorization of Radiofrequency Equipment

Science.gov (United States)

2013-05-03

...] Authorization of Radiofrequency Equipment AGENCY: Federal Communications Commission. ACTION: Proposed rule... bodies, and measurement procedures used to determine RF equipment compliance. The Commission believes... Commission is responsible for an equipment authorization program for radiofrequency (RF) devices under part 2...

Radiofrequency initiation and radiofrequency sustainment of laser initiated seeded high pressure plasma

International Nuclear Information System (INIS)

Paller, Eric S.; Scharer, John E.; Akhtar, Kamran; Kelly, Kurt; Ding, Guowen

2001-01-01

We examine radiofrequency initiation of high pressure(1-70 Torr) inductive plasma discharges in argon, nitrogen, air and organic seed gas mixtures. Millimeter wave interferometry, optical emission and antenna wave impedance measurements for double half-turn helix and helical inductive antennas are used to interpret the rf/plasma coupling, measure the densities in the range of 10 12 cm -3 and analyze the ionization and excited states of the gas mixtures. We have also carried out 193 nm excimer laser initiation of an organic gas seed plasma which is sustained at higher pressures(150 Torr) by radiofrequency coupling at 2.8 kW power levels

Hyperkalaemia after radiofrequency ablation of hepatocellular carcinoma

NARCIS (Netherlands)

Verhoevena, BH; Haagsma, EB; Appeltans, BMG; Slooff, MJH; de Jong, KP

Radiofrequency ablation of liver tumours is a useful therapy for otherwise unresectable tumours. The complication rate is said to be low. In this case report we describe hyperkalaemia after radiofrequency ablation of a hepatocellular carcinoma in a patient with end-stage renal insufficiency. (C)

Radio-frequency integrated-circuit engineering

CERN Document Server

Nguyen, Cam

2015-01-01

Radio-Frequency Integrated-Circuit Engineering addresses the theory, analysis and design of passive and active RFIC's using Si-based CMOS and Bi-CMOS technologies, and other non-silicon based technologies. The materials covered are self-contained and presented in such detail that allows readers with only undergraduate electrical engineering knowledge in EM, RF, and circuits to understand and design RFICs. Organized into sixteen chapters, blending analog and microwave engineering, Radio-Frequency Integrated-Circuit Engineering emphasizes the microwave engineering approach for RFICs. Provide

Radiofrequency catheter oblation in atrial flutter

International Nuclear Information System (INIS)

Yan Ji; Wang Heping; Xu Jian; Liu Fuyuan; Fan Xizhen; An Chunsheng; Han Xiaoping; Ding Xiaomei; Wang Jiasheng; Gu Tongyuan

2002-01-01

Objective: To evaluate the radiofrequency catheter ablation for type I atrial flutter through application of Holo catheter labelling with anatomic imaging localization to ablate the isthmus of IVCTA during complete double-way block. Methods: Eleven cases with type I atrial flutter undergone Holo catheter labelling technique and consecution with conduction time change of coronary venous sinus orifice with-right atrial lower lateral wall pace excitation, were performed with radiofrequency catheter ablation for the isthmus outcoming with complete double-way conduction block. Results: All together 11 cases with 4 of atrial flutter and 7 of sinus rhythm were undergone radiofrequency catheter ablation resulting with double-way conduction block of the isthmus accompanied by prolongation of right atrial conduction time 56.0 ± 2.3 ms and 53.0 ± 4.6 ms respectively. The right atrial excitation appeared to be in clockwise and counter-clockwise of single direction. No recurrence occurred during 3-34 months follow up with only one showing atrial fibrillation. Conclusions: The application of Holo catheter labelling technique with anatomic imaging localization to achieve the double-way conduction block by radiofrequency catheter ablation of TVC-TA isthmus, is a reliable method for treating atrial flutter

Non-surgical radiofrequency facelift.

Science.gov (United States)

Narins, David J; Narins, Rhoda S

2003-10-01

There has been considerable interest in using non-ablative methods to rejuvenate the skin. The ThermaCool TC (Thermage Inc.) is a radiofrequency (RF) device that has been introduced to induce tightening of the address the problem of skin via a uniform volumetric heating into the deep dermis tightening, resulting in a 'non-surgical facelift'. Radiofrequency produces a uniform volumetric heating into the deep dermis. Twenty treatment areas in 17 patients were treated to evaluate the efficacy and safety of RF treatment to the brow and jowls. The technique was found to produce gradual tightening in most patients, and there were no adverse effects.

21 CFR 870.2910 - Radiofrequency physiological signal transmitter and receiver.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiofrequency physiological signal transmitter... Devices § 870.2910 Radiofrequency physiological signal transmitter and receiver. (a) Identification. A radiofrequency physiological signal transmitter and receiver is a device used to condition a physiological signal...

Radiofrequency-thermoablation in malignant liver disease

International Nuclear Information System (INIS)

Pichler, L.; Anzboeck, W.; Paertan, G.; Hruby, W.

2002-01-01

The clinical application of radiofrequency tumor ablation in primary liver tumors and metastatic liver disease is rapidly growing because this technique has proven to be simple, safe, and effective in first clinical studies. Most of the patients with malignant liver disease are not candidates for surgical resection due localisation or comorbidity, so radiofrequency therapy offers a good alternative for inoperable patients. With this method, high frequency alternating current is delivered to tissue via a needle electrode, the produced heat leads to coagulation necrosis. The largest focus of necrosis that can be induced with the currently available systems is approximately 4-5 cm with a single application. The radiofrequency needle is usually placed with US or CT guidance. For follow up examinations CT and MRI can be used, they proved to be equally accurate in the assessment of treatment response. (orig.) [de

Fractionated bipolar radiofrequency and bipolar radiofrequency potentiated by infrared light for treating striae: A prospective randomized, comparative trial with objective evaluation.

Science.gov (United States)

Harmelin, Yona; Boineau, Dominique; Cardot-Leccia, Nathalie; Fontas, Eric; Bahadoran, Philippe; Becker, Anne-Lise; Montaudié, Henri; Castela, Emeline; Perrin, Christophe; Lacour, Jean-Philippe; Passeron, Thierry

2016-03-01

Very few treatments for striae are based on prospective randomized trials. The objective of this study was to assess the efficacy of bipolar fractional radiofrequency and bipolar radiofrequency potentiated with infrared light, alone or combined, for treating abdominal stretch marks. Bicentric prospective interventional randomized controlled trial in the department of Dermatology of University Hospital of Nice and Aesthetics Laser Center of Bordeaux, France. Men and women of age 18 years or above, who presented for the treatment of mature or immature abdominal striae were included. The patients' abdomens were divided into four equal quadrants. Bipolar radiofrequency potentiated with infrared light and fractional bipolar radiofrequency were applied, alone or combined, and compared to the remaining untreated quadrant. The main criterion of evaluation was the measurement of depth of striae, using 3D photography at 6 months follow-up. A global assessment was also rated by the physician performing the treatment and by the patients. Histological analysis and confocal laser microscopy were additionally performed. A total of 22 patients were enrolled, and 384 striae were measured. In per protocol analysis mean striae depth was decreased by 21.64%, observed at 6 months follow-up with the combined approach, compared to an increase of 1.73% in the control group (P radiofrequency, combined with bipolar radiofrequency potentiated by infrared light, is an effective treatment of both immature and mature striae of the abdomen. © 2016 Wiley Periodicals, Inc.

Temperature-controlled radiofrequency ablation of cardiac tissue

DEFF Research Database (Denmark)

Petersen, H H; Chen, X; Pietersen, Adrian

1999-01-01

BACKGROUND: A variety of basic factors such as electrode tip pressure, flow around the electrode and electrode orientation influence lesion size during radiofrequency ablation, but importantly is dependent on the chosen mode of ablation. However, only little information is available for the frequ......BACKGROUND: A variety of basic factors such as electrode tip pressure, flow around the electrode and electrode orientation influence lesion size during radiofrequency ablation, but importantly is dependent on the chosen mode of ablation. However, only little information is available...... for the frequently used temperature-controlled mode. The purpose of the present experimental study was to evaluate the impact during temperature-controlled radiofrequency ablation of three basic factors regarding electrode-tissue contact and convective cooling on lesion size. METHODS AND RESULTS: In vitro strips......-controlled radiofrequency ablation increased external cooling of the electrode tip due to either flow of the surrounding liquid or poor electrode tissue contact, as exemplified by perpendicular versus parallel electrode orientation, increases lesion size significantly. This is in contrast to the impact of these factors...

Pulsed Radiofrequency Ablation for Treating Sural Neuralgia.

Science.gov (United States)

Abd-Elsayed, Alaa; Jackson, Markus; Plovanich, Elizabeth

2018-01-01

Sural neuralgia is persistent pain in the distribution of the sural nerve that provides sensation to the lateral posterior corner of the leg, lateral foot, and fifth toe. Sural neuralgia is a rare condition but can be challenging to treat and can cause significant limitation. We present 2 cases of sural neuralgia resistant to conservative management that were effectively treated by pulsed radiofrequency ablation. A 65-year-old female developed sural neuralgia after a foot surgery and failed conservative management. She had successful sural nerve blocks, and pulsed radiofrequency ablation led to an 80% improvement in her pain. A 33-year-old female presented with sural neuralgia secondary to two falls. The patient had tried several conservative modalities with no success. We performed diagnostic blocks and pulsed radiofrequency ablation, and the patient reported 80% improvement in her pain. Pulsed radiofrequency ablation may be a safe and effective treatment for patients with sural neuralgia that does not respond to conservative therapy. However, studies are needed to elucidate its effectiveness and safety profile.

Directed and persistent movement arises from mechanochemistry of the ParA/ParB system.

Science.gov (United States)

Hu, Longhua; Vecchiarelli, Anthony G; Mizuuchi, Kiyoshi; Neuman, Keir C; Liu, Jian

2015-12-22

The segregation of DNA before cell division is essential for faithful genetic inheritance. In many bacteria, segregation of low-copy number plasmids involves an active partition system composed of a nonspecific DNA-binding ATPase, ParA, and its stimulator protein ParB. The ParA/ParB system drives directed and persistent movement of DNA cargo both in vivo and in vitro. Filament-based models akin to actin/microtubule-driven motility were proposed for plasmid segregation mediated by ParA. Recent experiments challenge this view and suggest that ParA/ParB system motility is driven by a diffusion ratchet mechanism in which ParB-coated plasmid both creates and follows a ParA gradient on the nucleoid surface. However, the detailed mechanism of ParA/ParB-mediated directed and persistent movement remains unknown. Here, we develop a theoretical model describing ParA/ParB-mediated motility. We show that the ParA/ParB system can work as a Brownian ratchet, which effectively couples the ATPase-dependent cycling of ParA-nucleoid affinity to the motion of the ParB-bound cargo. Paradoxically, this resulting processive motion relies on quenching diffusive plasmid motion through a large number of transient ParA/ParB-mediated tethers to the nucleoid surface. Our work thus sheds light on an emergent phenomenon in which nonmotor proteins work collectively via mechanochemical coupling to propel cargos-an ingenious solution shaped by evolution to cope with the lack of processive motor proteins in bacteria.

The radiofrequency frontier: a review of radiofrequency and combined radiofrequency pulsed-light technology in aesthetic medicine.

Science.gov (United States)

Sadick, Neil; Sorhaindo, Lian

2005-05-01

Radiofrequency (RF) and combined RF light source technologies have established themselves as safe and effective treatment modalities for several dermatologic procedures, including skin tightening, hair and leg vein removal, acne scarring, skin rejuvenation, and wrinkle reduction. This article reviews the technology, clinical applications, and recent advances of RF and combined RF light/laser source technologies in aesthetic medicine.

Treatment of acne vulgaris with fractional radiofrequency microneedling.

Science.gov (United States)

Kim, Sang Tae; Lee, Kang Hoon; Sim, Hyung Jun; Suh, Kee Suck; Jang, Min Soo

2014-07-01

Fractional radiofrequency microneedling is a novel radiofrequency technique that uses insulated microneedles to deliver energy to the deep dermis at the point of penetration without destruction of the epidermis. It has been used for the treatment of various dermatological conditions including wrinkles, atrophic scars and hypertrophic scars. There have been few studies evaluating the efficacy of fractional radiofrequency microneedling in the treatment of acne, and none measuring objective parameters like the number of inflammatory and non-inflammatory acne lesions or sebum excretion levels. The safety and efficacy of fractional radiofrequency microneedling in the treatment of acne vulgaris was investigated. In a prospective clinical trial, 25 patients with moderate to severe acne were treated with fractional radiofrequency microneedling. The procedure was carried out three times at 1-month intervals. Acne lesion count, subjective satisfaction score, sebum excretion level and adverse effects were assessed at baseline and at 4, 8 and 12 weeks after the first treatment as well as 4, 8 and 12 weeks after the last treatment. Number of acne lesions (inflammatory and non-inflammatory) decreased. Sebum excretion and subjective satisfaction were more favorable at every time point compared with the baseline values (P acne vulgaris. © 2014 Japanese Dermatological Association.

Aerosols produced by evaporation of a uranium wire; Aerosols produits par evaporation d'un fil d'uranium

Energy Technology Data Exchange (ETDEWEB)

Morel, C [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1968-03-01

This work is devoted to the study of the aerosols formed when an uranium wire is evaporated in a normal or rarefied atmosphere, either with or without a drying agent. The heating of the wire can be either fast or slow. The first part is a study of aerosol production apparatus and of methods of measuring the aerosol. The second part presents the results obtained with various aerosols: the particles produced by the wire are less than one micron; during rapid heating, the granulometric distribution of the aerosol obeys a log-normal law; during slow heating, the distribution has two modes: one near 0.05 micron, the other close to 0.01 micron. (author) [French] Ce travail est consacre a l'etude des aerosols formes lors de l'evaporation d un fil d'uranium en atmosphere normale ou rarefiee en presence ou non de dessechant. Le chauffage du fil peut etre rapide ou lent. La premiere partie est une etude des appareils de production et des methodes de mesures de l'aerosol. La seconde partie consigne les resultats obtenus sur les differents aerosols: les particules emises par le fil sont inferieures au micron; lors d'un chauffage rapide, la repartition granulometrique de l'aerosol suit une loi log-normale; lors d un chauffage lent, la repartition presente deux modes: l'un voisin de 0.05 micron, l'autre voisin de 0.01 micron. (auteur)

Radiofrequency amplifier based on a DC superconducting quantum interference device

International Nuclear Information System (INIS)

Martinis, J.M.; Hilbert, C.; Clarke, J.

1986-01-01

A method is described of amplifying a radiofrequency signal consisting of: disposing a single symmetrically biased dc SQUID and an input coil within a superconducting shield, the dc SQUID having a superconducting ring interrupted by two shunted Josephson junctions, and the input coil being inductively coupled solely to the ring of the single SQUID, establishing a constant magnetic flux threading the SQUID ring, applying the radiofrequency signal to the input coil from outside of the superconducting shield, obtaining an amplified radiofrequency signal solely from across the ring of the single SQUID, transmitting the amplified radiofrequency signal from across the SQUID ring to the outside of the superconducting shield

New resonant circuits for the ISOLTRAP radiofrequency quadrupole trap

CERN Document Server

SENECAL, Pierre

2015-01-01

This report describes my work during my Summer Student Program. My main project was building and testing a resonance-circuit box for a radio-frequency power supply used with the radio-frequency cooler and buncher.

Radiofrequency for the Treatment of Lumbar Radicular Pain: Impact on Surgical Indications.

Science.gov (United States)

Trinidad, José Manuel; Carnota, Ana Isabel; Failde, Inmaculada; Torres, Luis Miguel

2015-01-01

Study Design. Quasiexperimental study. Objective. To investigate whether radiofrequency treatment can preclude the need for spinal surgery in both the short term and long term. Background. Radiofrequency is commonly used to treat lumbosacral radicular pain. Only few studies have evaluated its effects on surgical indications. Methods. We conducted a quasiexperimental study of 43 patients who had been scheduled for spinal surgery. Radiofrequency was indicated for 25 patients. The primary endpoint was the decision of the patient to reject spinal surgery 1 month and 1 year after treatment (pulsed radiofrequency of dorsal root ganglion, 76%; conventional radiofrequency of the medial branch, 12%; combined technique, 12%). The primary endpoint was the decision of the patient to reject spinal surgery 1 month and 1 year after treatment. In addition, we also evaluated adverse effects, ODI, NRS. Results. We observed after treatment with radiofrequency 80% of patients rejected spinal surgery in the short term and 76% in the long term. We conclude that radiofrequency is a useful treatment strategy that can achieve very similar outcomes to spinal surgery. Patients also reported a very high level of satisfaction (84% satisfied/very satisfied). We also found that optimization of the electrical parameters of the radiofrequency improved the outcome of this technique.

Radiofrequency for the Treatment of Lumbar Radicular Pain: Impact on Surgical Indications

Directory of Open Access Journals (Sweden)

José Manuel Trinidad

2015-01-01

Full Text Available Study Design. Quasiexperimental study. Objective. To investigate whether radiofrequency treatment can preclude the need for spinal surgery in both the short term and long term. Background. Radiofrequency is commonly used to treat lumbosacral radicular pain. Only few studies have evaluated its effects on surgical indications. Methods. We conducted a quasiexperimental study of 43 patients who had been scheduled for spinal surgery. Radiofrequency was indicated for 25 patients. The primary endpoint was the decision of the patient to reject spinal surgery 1 month and 1 year after treatment (pulsed radiofrequency of dorsal root ganglion, 76%; conventional radiofrequency of the medial branch, 12%; combined technique, 12%. The primary endpoint was the decision of the patient to reject spinal surgery 1 month and 1 year after treatment. In addition, we also evaluated adverse effects, ODI, NRS. Results. We observed after treatment with radiofrequency 80% of patients rejected spinal surgery in the short term and 76% in the long term. We conclude that radiofrequency is a useful treatment strategy that can achieve very similar outcomes to spinal surgery. Patients also reported a very high level of satisfaction (84% satisfied/very satisfied. We also found that optimization of the electrical parameters of the radiofrequency improved the outcome of this technique.

Symplicity multi-electrode radiofrequency renal denervation system feasibility study.

Science.gov (United States)

Whitbourn, Robert; Harding, Scott A; Walton, Antony

2015-05-01

The aim of this study was to test the safety and performance of the Symplicity™ multi-electrode radio-frequency renal denervation system which was designed to reduce procedure time during renal denervation. The multi-electrode radiofrequency renal denervation system feasibility study is a prospective, non-randomised, open label, feasibility study that enrolled 50 subjects with hypertension. The study utilises a new renal denervation catheter which contains an array of four electrodes mounted in a helical configuration at 90 degrees from each other to deliver radiofrequency energy simultaneously to all four renal artery quadrants for 60 seconds. The protocol specified one renal denervation treatment towards the distal end of each main renal artery with radiofrequency energy delivered for 60 seconds per treatment. Total treatment time for both renal arteries was two minutes. The 12-month change in office systolic blood pressure (SBP) and 24-hour SBP was -19.2±25.2 mmHg, prenal artery stenosis or hypertensive emergencies occurred. The Symplicity multi-electrode radiofrequency renal denervation system was associated with a significant reduction in SBP at 12 months and minimal complications whilst it also reduced procedure time. NCT01699529.

Treatment of Benign Thyroid Nodules: Comparison of Surgery with Radiofrequency Ablation.

Science.gov (United States)

Che, Y; Jin, S; Shi, C; Wang, L; Zhang, X; Li, Y; Baek, J H

2015-07-01

Nodular goiter is one of the most common benign lesions in thyroid nodule. The main treatment of the disease is still the traditional surgical resection, however there are many problems such as general anesthesia, surgical scar, postoperative thyroid or parathyroid function abnormalities, and high nodules recurrence rate in residual gland. The purpose of this study was to compare the efficacy, safety, and cost-effectiveness of 2 treatment methods, surgery and radiofrequency ablation, for the treatment of benign thyroid nodules. From May 2012 to September 2013, 200 patients with nodular goiters who underwent surgery (group A) and 200 patients treated by radiofrequency ablation (group B) were enrolled in this study. Inclusion criteria were the following: 1) cosmetic problem, 2) nodule-related symptoms, 3) hyperfunctioning nodules related to thyrotoxicosis, and 4) refusal of surgery (for group B). An internally cooled radiofrequency ablation system and an 18-ga internally cooled electrode were used. We compared the 2 groups in terms of efficacy, safety, and cost-effectiveness during a 1-year follow-up. After radiofrequency ablation, the nodule volume decreased significantly from 5.4 to 0.4 mL (P = .002) at the 12-month follow-up. The incidence of complications was significantly higher from surgery than from radiofrequency ablation (6.0% versus 1.0%, P = .002). Hypothyroidism was detected in 71.5% of patients after surgery but in none following radiofrequency ablation. The rate of residual nodules (11.9% versus 2.9%, P = .004) and hospitalization days was significantly greater after surgery (6.6 versus 2.1 days, P radiofrequency ablation are both effective treatments of nodular goiter. Compared with surgery, the advantages of radiofrequency ablation include fewer complications, preservation of thyroid function, and fewer hospitalization days. Therefore, radiofrequency ablation should be considered a first-line treatment for benign thyroid nodules. © 2015 by American

FooPar

DEFF Research Database (Denmark)

Hargreaves, F. P.; Merkle, D.

2013-01-01

We present FooPar, an extension for highly efficient Parallel Computing in the multi-paradigm programming language Scala. Scala offers concise and clean syntax and integrates functional programming features. Our framework FooPar combines these features with parallel computing techniques. Foo......, results based on a empirical analysis on two supercomputers are given. We achieve close-to-optimal performance wrt. theoretical peak performance. Based on this result we conclude that FooPar allows programmers to fully access Scalas design features without suffering from performance drops when compared...

Heat Sink Effect on Tumor Ablation Characteristics as Observed in Monopolar Radiofrequency, Bipolar Radiofrequency, and Microwave, Using Ex Vivo Calf Liver Model

Science.gov (United States)

Pillai, Krishna; Akhter, Javid; Chua, Terence C.; Shehata, Mena; Alzahrani, Nayef; Al-Alem, Issan; Morris, David L.

2015-01-01

Abstract Thermal ablation of liver tumors near large blood vessels is affected by the cooling effect of blood flow, leading to incomplete ablation. Hence, we conducted a comparative investigation of heat sink effect in monopolar (MP) and bipolar (BP) radiofrequency ablation (RFA), and microwave (MW) ablation devices. With a perfused calf liver, the ablative performances (volume, mass, density, dimensions), with and without heat sink, were measured. Heat sink was present when the ablative tip of the probes were 8.0 mm close to a major hepatic vein and absent when >30 mm away. Temperatures (T1 and T2) on either side of the hepatic vein near the tip of the probes, heating probe temperature (T3), outlet perfusate temperature (T4), and ablation time were monitored. With or without heat sink, BP radiofrequency ablated a larger volume and mass, compared with MP RFA or MW ablation, with latter device producing the highest density of tissue ablated. MW ablation produced an ellipsoidal shape while radiofrequency devices produced spheres. Percentage heat sink effect in Bipolar radiofrequency : Mono-polar radiofrequency : Microwave was (Volume) 33:41:22; (mass) 23:56:34; (density) 9.0:26:18; and (relative elipscity) 5.8:12.9:1.3, indicating that BP and MW devices were less affected. Percentage heat sink effect on time (minutes) to reach maximum temperature (W) = 13.28:9.2:29.8; time at maximum temperature (X) is 87:66:16.66; temperature difference (Y) between the thermal probes (T3) and the temperature (T1 + T2)/2 on either side of the hepatic vessel was 100:87:20; and temperature difference between the (T1 + T2)/2 and temperature of outlet circulating solution (T4), Z was 20.33:30.23:37.5. MW and BP radiofrequencies were less affected by heat sink while MP RFA was the most affected. With a single ablation, BP radiofrequency ablated a larger volume and mass regardless of heat sink. PMID:25738477

Occupational exposure to radiofrequency fields in antenna towers

International Nuclear Information System (INIS)

Alanko, T.; Hietanen, M.

2007-01-01

Exposure of workers to radiofrequency fields was assessed in two medium-sized antenna towers. Towers had transmitting antennas from different networks, e.g. mobile phone networks, radio and digital TV sub-stations and amateur radio. The levels of radiofrequency fields were measured close to the ladders of the towers. All measured values were below ICNIRP occupational reference levels. (authors)

Phosphorylation of Mycobacterium tuberculosis ParB participates in regulating the ParABS chromosome segregation system.

Science.gov (United States)

Baronian, Grégory; Ginda, Katarzyna; Berry, Laurence; Cohen-Gonsaud, Martin; Zakrzewska-Czerwińska, Jolanta; Jakimowicz, Dagmara; Molle, Virginie

2015-01-01

Here, we present for the first time that Mycobacterium tuberculosis ParB is phosphorylated by several mycobacterial Ser/Thr protein kinases in vitro. ParB and ParA are the key components of bacterial chromosome segregation apparatus. ParB is a cytosolic conserved protein that binds specifically to centromere-like DNA parS sequences and interacts with ParA, a weak ATPase required for its proper localization. Mass spectrometry identified the presence of ten phosphate groups, thus indicating that ParB is phosphorylated on eight threonines, Thr32, Thr41, Thr53, Thr110, Thr195, and Thr254, Thr300, Thr303 as well as on two serines, Ser5 and Ser239. The phosphorylation sites were further substituted either by alanine to prevent phosphorylation or aspartate to mimic constitutive phosphorylation. Electrophoretic mobility shift assays revealed a drastic inhibition of DNA-binding by ParB phosphomimetic mutant compared to wild type. In addition, bacterial two-hybrid experiments showed a loss of ParA-ParB interaction with the phosphomimetic mutant, indicating that phosphorylation is regulating the recruitment of the partitioning complex. Moreover, fluorescence microscopy experiments performed in the surrogate Mycobacterium smegmatis ΔparB strain revealed that in contrast to wild type Mtb ParB, which formed subpolar foci similar to M. smegmatis ParB, phoshomimetic Mtb ParB was delocalized. Thus, our findings highlight a novel regulatory role of the different isoforms of ParB representing a molecular switch in localization and functioning of partitioning protein in Mycobacterium tuberculosis.

Phosphorylation of Mycobacterium tuberculosis ParB participates in regulating the ParABS chromosome segregation system.

Directory of Open Access Journals (Sweden)

Grégory Baronian

Full Text Available Here, we present for the first time that Mycobacterium tuberculosis ParB is phosphorylated by several mycobacterial Ser/Thr protein kinases in vitro. ParB and ParA are the key components of bacterial chromosome segregation apparatus. ParB is a cytosolic conserved protein that binds specifically to centromere-like DNA parS sequences and interacts with ParA, a weak ATPase required for its proper localization. Mass spectrometry identified the presence of ten phosphate groups, thus indicating that ParB is phosphorylated on eight threonines, Thr32, Thr41, Thr53, Thr110, Thr195, and Thr254, Thr300, Thr303 as well as on two serines, Ser5 and Ser239. The phosphorylation sites were further substituted either by alanine to prevent phosphorylation or aspartate to mimic constitutive phosphorylation. Electrophoretic mobility shift assays revealed a drastic inhibition of DNA-binding by ParB phosphomimetic mutant compared to wild type. In addition, bacterial two-hybrid experiments showed a loss of ParA-ParB interaction with the phosphomimetic mutant, indicating that phosphorylation is regulating the recruitment of the partitioning complex. Moreover, fluorescence microscopy experiments performed in the surrogate Mycobacterium smegmatis ΔparB strain revealed that in contrast to wild type Mtb ParB, which formed subpolar foci similar to M. smegmatis ParB, phoshomimetic Mtb ParB was delocalized. Thus, our findings highlight a novel regulatory role of the different isoforms of ParB representing a molecular switch in localization and functioning of partitioning protein in Mycobacterium tuberculosis.

Radiofrequency ablation of liver tumors (II): clinical application and outcomes.

Science.gov (United States)

Vanagas, Tomas; Gulbinas, Antanas; Pundzius, Juozas; Barauskas, Giedrius

2010-01-01

Radiofrequency ablation is one of the alternatives in the management of liver tumors, especially in patients who are not candidates for surgery. The aim of this article is to review applicability of radiofrequency ablation achieving complete tumor destruction, utility of imaging techniques for patients' follow-up, indications for local ablative procedures, procedure-associated morbidity and mortality, and long-term results in patients with different tumors. The success of local thermal ablation consists in creating adequate volumes of tissue destruction with adequate "clear margin," depending on improved delivery of radiofrequency energy and modulated tissue biophysiology. Different volumes of coagulation necrosis are achieved applying different types of electrodes, pulsing energy sources, utilizing sophisticated ablation schemes. Some additional methods are used to increase the overall deposition of energy through alterations in tissue electrical conductivity, to improve heat retention within the tissue, and to modulate tolerance of tumor tissue to hyperthermia. Contrast-enhanced computed tomography, magnetic resonance imaging, ultrasound or positron emission tomography are applied to control the effectiveness of radiofrequency ablation. The long-term results of radiofrequency ablation are controversial.

77 FR 43535 - Grantee Codes for Certified Radiofrequency Equipment

Science.gov (United States)

2012-07-25

... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 2 [FCC 12-60] Grantee Codes for Certified Radiofrequency Equipment AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY: This document... authorization program for radiofrequency (RF) devices under part 2 of its rules. This program is one of the...

Clinical application and developmental trend of radiofrequency ablation technology

International Nuclear Information System (INIS)

Chen Dongfeng

2009-01-01

For recent two decades, radiofrequency ablation technology has made great progress in the field of the treatment for neoplasm. At the very beginning, radiofrequency ablation was adopted in treating the hepatic carcinoma, and since then it has been gradually practiced in treating malignancies of lung, bone, kidney, breast, prostate and other solid tumors. Statistical report of the year 2008 has indicated that in the aspect of similar therapeutic measures radiofrequency ablation therapy for tumors holds a 9% market share. Moreover, in the coming years the clinical use of this kind of therapy for tumors will be steadily increasing by 13% every year. (authors)

Direct measurement of the lethal isotherm for radiofrequency ablation of myocardial tissue.

Science.gov (United States)

Wood, Mark; Goldberg, Scott; Lau, Melissa; Goel, Aneesh; Alexander, Daniel; Han, Frederick; Feinstein, Shawn

2011-06-01

The lethal isotherm for radiofrequency catheter ablation of cardiac myocardium is widely accepted to be 50°C, but this has not been directly measured. The purpose of this study was to directly measure the tissue temperature at the edge of radiofrequency lesions in real time using infrared thermal imaging. Fifteen radiofrequency lesions of 6 to 240 seconds in duration were applied to the left ventricular surface of isolated perfused pig hearts. At the end of radiofrequency delivery, a thermal image of the tissue surface was acquired with an infrared camera. The lesion was then stained and an optical image of the lesion was obtained. The thermal and optical images were electronically merged to allow determination of the tissue temperature at the edge of the lesion at the end of radiofrequency delivery. By adjusting the temperature overlay display to conform with the edge of the radiofrequency lesion, the lethal isotherm was measured to be 60.6°C (interquartile ranges, 59.7° to 62.4°C; range, 58.1° to 64.2°C). The areas encompassed by the lesion border in the optical image and the lethal isotherm in the thermal image were statistically similar and highly correlated (Spearman ρ=0.99, Pradiofrequency delivery or to lesion size (both P>0.64). The areas circumscribed by 50°C isotherms were significantly larger than the areas of the lesions on optical imaging (P=0.002). By direct measurement, the lethal isotherm for cardiac myocardium is near 61°C for radiofrequency energy deliveries radiofrequency ablation is important to clinical practice as well as mathematical modeling of radiofrequency lesions.

Level of Radiofrequency (RF) Radiations from GSM Base Stations ...

African Journals Online (AJOL)

Levels of radiofrequency radiations around two global systems for mobile communication (GSM) base stations located in the vicinity of a residential quarter and workplace complex were measured. The effects of the radiofrequency radiations on albino mice placed in exposure cages and located around the base stations ...

Radiofrequency ablation of osteoid osteomas: five years experience.

Science.gov (United States)

Papathanassiou, Zafiria G; Petsas, Theodore; Papachristou, Dionysios; Megas, Panagiotis

2011-12-01

The purpose of this study is to retrospectively evaluate the efficacy of radiofrequency ablation as a curative treatment method for benign bone tumours. Twenty-nine osteoid osteomas were treated with radiofrequency ablation. Primary success rate was 89.6% and total secondary success rate was 93.1%. Mean clinical follow-up period was 26.7 months (range: 6-63 months). Statistical analysis of 25 cases of osteoid osteomas with CT follow-up revealed that post-treatment re-ossification does not correlate with clinical outcome (p = 0.14) but is strongly correlated with long-term (> or = 12 months) CT follow-up (p = 0.014). Percutaneous radiofrequency ablation was found to be an effective and safe treatment for osteoid osteomas. CT findings cannot solely differentiate between treatment successes and failures.

Interactions between radiofrequency signals and living organisms

International Nuclear Information System (INIS)

Boudin, F.; Hours, M.; Lacronique, J.F.; Conil, E.; Hadjem, A.; El Habachi, A.; Wiart, K.; Mann, S.; Kundi, M.; Marc-Vergnes, J.P.; Roosli, M.; Mohler, E.; Frei, P.; Davis, Ch.C.; Balzano, Q.; Ait-Aissa, S.; Billaudel, B.; Poulletier De Gannes, F.; Hurtier, A.; Haro, E.; Taxile, M.; Veyret, B.; Lagroye, I.; Ait-Aissa, S.; Poulletier De Gannes, F.; Athane, A.; Veyret, B.; Lagroye, I.; Yardin, C.; Perrin, A.; Freire, M.; Bachelet, Ch.; Collin, A.; Pla, S.; Debouzy, J.C.; Leveque, Ph.; Van Nierop, L.E.; Huss, A.; Roosli, M.; Egger, M.; Calvez, M.; Salomon, D.

2010-01-01

This dossier is composed of 13 articles dealing with the interactions between radio-frequencies and living organisms. It is an overview of various scientific approaches to the field and is of interest for all citizens as the use of mobile phones is widely spread. In the first article it is shown how a model has been built to assess the distribution of the whole body exposure of the population. The second article reviews the state of the art in personal exposure measurements at radio-frequencies. The third article shows that the knowledge of the mechanism of action by which exposure increases the risk of health hazards is necessary. The fourth article shows that individual neuro-psychic factors take a prominent but maybe not unique, part in electromagnetic hypersensitivity. The fifth article shows that no evidence was found to link health disturbances of electromagnetic hypersensitive individuals with radiofrequency exposure. The sixth article shows that the wireless phone is not an athermal hazard to the brain. The seventh article shows that the in utero and post-natal exposure to Wi-Fi does not damage the brains of young rats. The eighth article concludes that recent studies provide no convincing proof of deleterious effects of radiofrequency exposure on the integrity of the blood-brain barrier for specific absorption rates up to 6 W/kg. The ninth article shows that no co-genotoxic effect of radiofrequency was found at levels of exposure that did not induce heating. The tenth article confirms that industry-sponsored studies were least likely to report results suggesting effects. The last article shows that general practitioners are increasingly questioned by their patients about the issue of electromagnetic waves. (A.C.)

Radiofrequency catheter ablation in the treatment of cardiac arrhythmias (first of two parts)

International Nuclear Information System (INIS)

Kou, W.H; Morady, F.

1997-01-01

The intravenous radiofrequency catheter inside cardiac s chambers, for inspect signals intracardiac s and to encourage, has been developed as diagnostic tool with the purpose to search arrhythmias physiology and physiopathology.Many energy sources has been used: direct energy, radiofrequency 11-15, laser 6,17, and microwave 18,19. A comparison between radiofrequency and electric energy shock has been described in cardiac arrhythmias treatment, in the present article. It has been tested the radiation biological effects and risk in Wolff Parkinson White patients as well as doctors who handling the fluoroscopy for image during the radiofrequency ablation. Has been described the following techniques: Catheter ablation radiofrequency slow way and fast way

Reconfigurable radio-frequency arbitrary waveforms synthesized in a silicon photonic chip.

Science.gov (United States)

Wang, Jian; Shen, Hao; Fan, Li; Wu, Rui; Niu, Ben; Varghese, Leo T; Xuan, Yi; Leaird, Daniel E; Wang, Xi; Gan, Fuwan; Weiner, Andrew M; Qi, Minghao

2015-01-12

Photonic methods of radio-frequency waveform generation and processing can provide performance advantages and flexibility over electronic methods due to the ultrawide bandwidth offered by the optical carriers. However, bulk optics implementations suffer from the lack of integration and slow reconfiguration speed. Here we propose an architecture of integrated photonic radio-frequency generation and processing and implement it on a silicon chip fabricated in a semiconductor manufacturing foundry. Our device can generate programmable radio-frequency bursts or continuous waveforms with only the light source, electrical drives/controls and detectors being off-chip. It modulates an individual pulse in a radio-frequency burst within 4 ns, achieving a reconfiguration speed three orders of magnitude faster than thermal tuning. The on-chip optical delay elements offer an integrated approach to accurately manipulating individual radio-frequency waveform features without constraints set by the speed and timing jitter of electronics, and should find applications ranging from high-speed wireless to defence electronics.

Fast beam radiofrequency spectroscopy

International Nuclear Information System (INIS)

Pipkin, F.M.

1983-01-01

The combination of a fast atom or ion beam derived from a small accelerator with radiofrequency spectroscopy methods provides a powerful method for measuring the fine structure of atomic and molecular systems. The fast beam makes possible measurements in which two separated oscillatory fields are used to obtain resonance lines whose widths are less than the natural line width due to the lifetimes of the states. The separated oscillatory field lines have, in addition, a number of features which make possible measurements with greater precision and less sensitivity to systematic errors. The fast beam also makes accessible multiple photon radiofrequency transitions whose line width is intrinsically narrower than that of the single photon transitions and which offer great potential for high precision measurements. This report focuses on the techniques and their promise. Recent measurements of the fine structure of H and He + are used as illustrations

ParA and ParB coordinate chromosome segregation with cell elongation and division during Streptomyces sporulation

Science.gov (United States)

Donczew, Magdalena; Mackiewicz, Paweł; Wróbel, Agnieszka; Flärdh, Klas; Zakrzewska-Czerwińska, Jolanta

2016-01-01

In unicellular bacteria, the ParA and ParB proteins segregate chromosomes and coordinate this process with cell division and chromosome replication. During sporulation of mycelial Streptomyces, ParA and ParB uniformly distribute multiple chromosomes along the filamentous sporogenic hyphal compartment, which then differentiates into a chain of unigenomic spores. However, chromosome segregation must be coordinated with cell elongation and multiple divisions. Here, we addressed the question of whether ParA and ParB are involved in the synchronization of cell-cycle processes during sporulation in Streptomyces. To answer this question, we used time-lapse microscopy, which allows the monitoring of growth and division of single sporogenic hyphae. We showed that sporogenic hyphae stop extending at the time of ParA accumulation and Z-ring formation. We demonstrated that both ParA and ParB affect the rate of hyphal extension. Additionally, we showed that ParA promotes the formation of massive nucleoprotein complexes by ParB. We also showed that FtsZ ring assembly is affected by the ParB protein and/or unsegregated DNA. Our results indicate the existence of a checkpoint between the extension and septation of sporogenic hyphae that involves the ParA and ParB proteins. PMID:27248800

Enhanced Radiofrequency Ablation With Magnetically Directed Metallic Nanoparticles.

Science.gov (United States)

Nguyen, Duy T; Tzou, Wendy S; Zheng, Lijun; Barham, Waseem; Schuller, Joseph L; Shillinglaw, Benjamin; Quaife, Robert A; Sauer, William H

2016-05-01

Remote heating of metal located near a radiofrequency ablation source has been previously demonstrated. Therefore, ablation of cardiac tissue treated with metallic nanoparticles may improve local radiofrequency heating and lead to larger ablation lesions. We sought to evaluate the effect of magnetic nanoparticles on tissue sensitivity to radiofrequency energy. Ablation was performed using an ablation catheter positioned with 10 g of force over prepared ex vivo specimens. Tissue temperatures were measured and lesion volumes were acquired. An in vivo porcine thigh model was used to study systemically delivered magnetically guided iron oxide (FeO) nanoparticles during radiofrequency application. Magnetic resonance imaging and histological staining of ablated tissue were subsequently performed as a part of ablation lesion analysis. Ablation of ex vivo myocardial tissue treated with metallic nanoparticles resulted in significantly larger lesions with greater impedance changes and evidence of increased thermal conductivity within the tissue. Magnet-guided localization of FeO nanoparticles within porcine thigh preps was demonstrated by magnetic resonance imaging and iron staining. Irrigated ablation in the regions with greater FeO, after FeO infusion and magnetic guidance, created larger lesions without a greater incidence of steam pops. Metal nanoparticle infiltration resulted in significantly larger ablation lesions with altered electric and thermal conductivity. In vivo magnetic guidance of FeO nanoparticles allowed for facilitated radiofrequency ablation without direct infiltration into the targeted tissue. Further research is needed to assess the clinical applicability of this ablation strategy using metallic nanoparticles for the treatment of cardiac arrhythmias. © 2016 American Heart Association, Inc.

Percutaneous radiofrequency treatment for refractory anteromedial pain of osteoarthritic knees.

Science.gov (United States)

Ikeuchi, Masahiko; Ushida, Takahiro; Izumi, Masashi; Tani, Toshikazu

2011-04-01

Although severe knee osteoarthritis with refractory pain is commonly treated surgically, this is often not an option for patients with poor health status or unwillingness to undergo major surgery. We examined the efficacy of radiofrequency application to sensory nerves as a novel alternative treatment for refractory knee pain. This study was an open-label, nonrandomized, and controlled study. Patients complaining of refractory anteromedial knee pain associated with radiological osteoarthritis (moderate or severe) were included. They were assigned to one of two groups: those receiving radiofrequency thermocoagulation (N = 18) or those receiving nerve block (N = 17), depending on the time period that they were referred to the clinic. Radiofrequency current or local anesthetics was applied to the medial retinacular nerve and the infrapatellar branch of the saphenous nerve. Western Ontario McMaster Universities osteoarthritis index score, pain visual analog scale (VAS), and patient's global assessment were assessed with a minimum follow-up of 6 months.   Radiofrequency treatment significantly decreased knee pain as measured by VAS for 12 weeks compared with the control group. In terms of responders, more patients in the RF group responded to the treatment than in the control group. The differences were statistically significant at 4 weeks, 8 weeks, and 12 weeks in pain VAS. Eight patients (44%) treated with radiofrequency rated excellent or good but only three (18%) in the control group rated good, although the difference was not statistically significant. Some patients were able to benefit substantially from radiofrequency treatment. Even if its effective period is limited, radiofrequency application is a promising treatment to alleviate refractory anteromedial knee pain with osteoarthritis. Further experience and technical improvements are needed to establish its role in the management of knee osteoarthritis. Wiley Periodicals, Inc.

Treatment of Refractory Idiopathic Supraorbital Neuralgia Using Percutaneous Pulsed Radiofrequency.

Science.gov (United States)

Luo, Fang; Lu, Jingjing; Ji, Nan

2018-02-26

No ideal therapeutic method currently exists for refractory idiopathic supraorbital neuralgia patients who do not respond to conservative therapy, including medications and nerve blocks. Pulsed radiofrequency is a neuromodulation technique that does not produce sequelae of nerve damage after treatment. However, the efficacy of percutaneous pulsed radiofrequency for the treatment of refractory idiopathic supraorbital neuralgia is still not clear. The purpose of our study was to evaluate the efficacy and safety of pulsed radiofrequency treatment of the supraorbital nerve for refractory supraorbital neuralgia patients. We prospectively investigated the long-term effects of ultrasound-guided percutaneous pulsed radiofrequency in the treatment of 22 refractory idiopathic supraorbital neuralgia patients. A reduction in the verbal pain numeric rating scale score of more than 50% was used as the standard of effectiveness. The effectiveness rates at different time points within 2 years were calculated. After a single pulsed radiofrequency treatment, the effectiveness rate at 1 and 3 months was 77%, and the rates at 6 months, 1 year, and 2 years were 73%, 64%, and 50%, respectively. Except for a small portion of patients (23%) who experienced mild upper eyelid ecchymosis that gradually disappeared after approximately 2 weeks, no obvious complications were observed. In conclusion, the results of our study demonstrate that for patients with refractory idiopathic supraorbital neuralgia, percutaneous pulsed radiofrequency may be an effective and safe treatment choice. © 2018 World Institute of Pain.

Percutaneous radiofrequency treatment of osteoid osteoma using cool-tip electrodes

Energy Technology Data Exchange (ETDEWEB)

Martel, Jose [Departamento de Diagnostico por Imagen, Fundacion Hospital Alcorcon, Avda. de Budapest s/n, 28922 Alcorcon, Madrid (Spain)]. E-mail: jmartel@fhalcorcon.es; Bueno, Angel [Departamento de Diagnostico por Imagen, Fundacion Hospital Alcorcon, Avda. de Budapest s/n, 28922 Alcorcon, Madrid (Spain); Ortiz, Eduardo [Departamento de Cirugia ortopedica, Fundacion Hospital Alcorcon, Madrid (Spain)

2005-12-15

Objectives: To report our experience with percutaneous cool-tip radiofrequency ablation of osteoid osteomas and to evaluate clinical outcome. Methods and material: Forty-one patients with clinically and radiologically suspected osteoid osteoma were seen over a 48-month period (27 males and 14 females with a mean age of 18.7 years; range 5-43 years). Thirty-eight patients were treated by computed tomography (CT)-guided percutaneous radiofrequency ablation. The procedure was performed under regional or general anaesthesia. After location of the nidus, a 14G-bone biopsy needle is introduced into the nidus. Sampling is performed with a 17G-bone biopsy needle using a coaxial technique. The radiofrequency needle with a 10 mm active tip (cool-tip) is inserted through the biopsy needle and is connected to the radiofrequency generator for 6-8 min. Results: Primary success was obtained in 37 patients (97%) with a 100% secondary success rate. All patients are currently pain-free. No major complications occurred. Patients could resume unrestricted normal activity within 24 h. Conclusions: Percutaneous radiofrequency ablation of osteoid osteomas is an efficient and safe method that can be considered the procedure of choice for most cases.

Par Pond water balance

International Nuclear Information System (INIS)

Hiergesell, R.A.; Dixon, K.L.

1996-06-01

A water budget for the Par Pond hydrologic system was established in order to estimate the rate of groundwater influx to Par Pond. This estimate will be used in modeling exercises to predict Par Pond reservoir elevation and spillway discharge in the scenario where Savannah River water is no longer pumped and discharged into Par Pond. The principal of conservation of mass was used to develop the water budget, where water inflow was set equal to water outflow. Components of the water budget were identified, and the flux associated with each was determined. The water budget was considered balanced when inflow and outflow summed to zero. The results of this study suggest that Par Pond gains water from the groundwater system in the upper reaches of the reservoir, but looses water to the groundwater system near the dam. The rate of flux of groundwater from the water table aquifer into Par Pond was determined to be 13 cfs. The rate of flux from Par Pond to the water table aquifer near the dam was determined to be 7 cfs

Visualizing radiofrequency-skin interaction using multiphoton microscopy in vivo.

Science.gov (United States)

Tsai, Tsung-Hua; Lin, Sung-Jan; Lee, Woan-Ruoh; Wang, Chun-Chin; Hsu, Chih-Ting; Chu, Thomas; Dong, Chen-Yuan

2012-02-01

Redundant skin laxity is a major feature of aging. Recently, radiofrequency has been introduced for nonablative tissue tightening by volumetric heating of the deep dermis. Despite the wide range of application based on this therapy, the effect of this technique on tissue and the subsequent tissue remodeling have not been investigated in detail. Our objective is to evaluate the potential of non-linear optics, including multiphoton autofluorescence and second harmonic generation (SHG) microscopy, as a non-invasive imaging modality for the real-time study of radiofrequency-tissue interaction. Electro-optical synergy device (ELOS) was used as the radiofrequency source in this study. The back skin of nude mouse was irradiated with radiofrequency at different passes. We evaluated the effect on skin immediately and 1 month after treatment with multiphoton microscopy. Corresponding histology was performed for comparison. We found that SHG is negatively correlated to radiofrequency passes, which means that collagen structural disruption happens immediately after thermal damage. After 1 month of collagen remodeling, SHG signals increased above baseline, indicating that collagen regeneration has occurred. Our findings may explain mechanism of nonablative skin tightening and were supported by histological examinations. Our work showed that monitoring the dermal heating status of RF and following up the detailed process of tissue reaction can be imaged and quantified with multiphoton microscopy non-invasively in vivo. Copyright © 2011. Published by Elsevier Ireland Ltd.

Estudio Te\\'orico del espectro de emisi\\'on para un sistema microcavidad-punto cu\\'antico en una aproximaci\\'on de campo medio (Theoretical study of emission spectrum for a quantum dot-microcavity system in a mean field approximation)

OpenAIRE

Rojas-Arias, Juan S.; Rodriguez, B.; Vinck-Posada, Herbert

2015-01-01

En este trabajo, se obtiene una expresi\\'on num\\'erica para calcular el espectro de emisi\\'on de un sistema microcavidad-punto cu\\'antico usando una teor\\'ia de campo medio en el formalismo de la matriz densidad. El sistema modelado es un micropilar semiconductor que contiene un \\'unico punto cu\\'antico en el interior de la microcavidad, este sistema presenta p\\'erdida de fotones a trav\\'es de los espejos de la cavidad y bombeo de excitones al punto cu\\'antico. Obtenemos una ecuaci\\'on maestr...

Effect of radiofrequency on capacitance of low density plasma sheath

International Nuclear Information System (INIS)

Carneiro, L.T.; Cunha Rapozo, C. da

1988-01-01

It is shown that the influence of induced radiofrequency potential (V RF ) modifies the Bohm theory on ion saturation current, measured with Langmuir probes. The effect of radiofrequency potential on diode type plasma sheath resonance is also investigated. (M.C.K.)

Eye examinations of laser and radiofrequency radiation workers

International Nuclear Information System (INIS)

Hocking, B.

1988-01-01

There are a growing number of uses of lasers and radiofrequency radiation in industry. Because these radiations may lead to various ocular effects, examinations of the eye are required for laser and radiofrequency workers as part of safe working practices. Various issues concerning these examinations are raised for discussion including: handling personal data, placement criteria, data collection, quality control, control data, the load on service providers, and costs

suPAR

DEFF Research Database (Denmark)

Hodges, Gethin W; Bang, Casper N; Wachtell, Kristian

2015-01-01

The fundamental role of inflammation in cardiovascular disease (CVD) has prompted interest in numerous biomarkers that detect subclinical levels of inflammation. Soluble urokinase plasminogen activator receptor (suPAR) is a novel biomarker that correlates significantly with cardiovascular events ...... comprehensive review of suPAR in CVD and explore its function and usefulness in predicting cardiovascular events....

Bray–Liebhafsky oscillatory reaction in the radiofrequency electromagnetic field

Energy Technology Data Exchange (ETDEWEB)

Stanisavljev, Dragomir R., E-mail: dragisa@ffh.bg.ac.rs [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, P.O. Box 473, 11001 Belgrade (Serbia); Velikić, Zoran [Institute of Physics, University of Belgrade, Pregrevica 118, Zemun (Serbia); Veselinović, Dragan S.; Jacić, Nevena V.; Milenković, Maja C. [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, P.O. Box 473, 11001 Belgrade (Serbia)

2014-09-30

Highlights: • Oscillatory Bray–Liebhafsky reaction is coupled with the radiofrequency radiation. • The effects of radiofrequency field on oscillatory parameters are investigated. • Radiofrequency power of up to the 0.2 W did not produced observable changes. • The explanation related with dissipative and capacitive effects is given. • Open the possibility of investigations of reactive effects on biological systems. - Abstract: Oscillatory Bray–Liebhafsky (BL) reaction is capacitively coupled with the electromagnetic radiation in the frequency range 60–110 MHz. Because of the specific reaction dynamics characterized by several characteristic parameters (induction period, period between chemical oscillations and their amplitude) it served as a good model system for the investigation of the effects of radiofrequent (RF) radiation. RF power of up to 0.2 W did not produce observable changes of the BL reaction parameters in the limit of the experiment reproductivity. Results indicate that, under the given experimental conditions, both dissipative and reactive properties of the solution are not considerably coupled with the RF electrical field.

C9.A/14 steelwork joints de poutres par plaque frontale : assemblages par gousset

CERN Document Server

2015-01-01

Les Tables de résistances ultimes des assemblages boulonnés par plaque frontale et par gousset, complétées par une description des modèles de calcul et des exemples d’application, ont pour but de faciliter la tâche de l'ingénieur et du constructeur. Cette première partie C9.A/14 contient les chapitres suivants: - Joints de poutres par plaque frontale en acier S235 et S355 - Assemblages par gousset en acier S235 et S355 Les Tables contiennent des données relatives à la géométrie ainsi que les valeurs de calcul correspondantes des résistances ultimes des assemblages ; elles remplacent le chapitre « Assemblages par plaques frontales et boulons HR » des anciennes Tables C9.1 de 1983 / 2002. Le calcul de ces assemblages par plaque frontale est basé sur les hypothèses du modèle de la méthode des composants décrite dans la norme SN EN 1993-1-8. Les vérifications sont effectuées selon la norme SIA 263:2013. Les assemblages par gousset remplacent les assemblages par double cornière, (telle...

Percutaneous radiofrequency ablation for benign nodules of the thyroid gland

International Nuclear Information System (INIS)

Baek, Jung Hwan; Jeong, Hyun Jo; Kim, Yoon Suk; Kwak, Min Sook; Chang, Sun Hee; Rhim, Hyun Chul

2005-01-01

We wanted to evaluate the efficacy and safety of using ultrasound guided percutaneous radiofrequency ablation for the benign nodules of the thyroid gland. We studied 148 patients with benign thyroid nodules (200 total nodules) that were confirmed histopathologically, and we performed ultrasound guided radiofrequency ablation. The radiofrequency ablation was done 1 to 5 times per one nodule, and follow-up ultrasonography was performed one to nineteen months after the ablation procedures. The physical changes and the decrease of volume of the nodules were evaluated, and the complications related to radiofrequency ablation were observed. The mean initial nodule volume was 0.01-95.61 ml (mean; 6.83 ± SD of 10.63 ml) and the nodule volume after radiofrequency ablation was decreased to 0.00-46.56 ml (mean; 1.83 ± SD of 4.69 ml). The mean volume reduction rate was 73.2%. Reduction of more than 50% was noted in 90% of all cases. For 180 nodules (90%), the decrease was 50% or more, in 20 nodules (10%), the decrease was 49% or less. On gray-scale ultrasonogram obtained after ablation, the echogenicity of the nodules changed to darker, and on the doppler-sonogram, the vascular flow within the nodules disappeared in all cases. Most patients complained pain during or right after the procedure, but the pain was transient and subsided after medication. Two patients developed hoarseness that was improved in 1 week and 2 months, respectively. Sonoguided percutaneous radiofrequency ablation can be one of the treatments for benign nodules of the thyroid gland

Knee cooled radiofrequency vs continuous radiofrequency for genicular neurotomy: preliminary experience - Crio-radiofrequenza vs radiofrequenza continua per neurotomia dei nervi genicolati: esperienza preliminare

Directory of Open Access Journals (Sweden)

Alfonso Papa

2016-09-01

Full Text Available Radiofrequency neurotomy of genicular nerves has been often used as an efficacious treatment option in all patients suffering from chronic osteoarthritis pain to provide long-term pain relief. After providing informed written consent, 80 patients with severe knee chronic osteoarthritis pain had been enrolled; patients had been divided into two groups (Group C, crioneurolysis, vs Group R, traditional radiofrequency, 40 patients for each group. Pain relief in C group was poorer and with shorter time in duration (median NRS reducing from 8 to 5. Radiofrequency can be considered as an effective, minimally invasive treat­ment for these kinds of conditions, and offers the benefit of being a fast procedure with long-term pain relief.

Mechanisms for enlarging lesion size during irrigated tip radiofrequency ablation

DEFF Research Database (Denmark)

Petersen, Helen Høgh; Roman-Gonzalez, Javier; Johnson, Susan B

2004-01-01

INTRODUCTION: Irrigated tip radiofrequency ablation of cardiac arrhythmias was developed to increase the size of the radiofrequency-induced lesion, since cooling of the electrode tip allows use of higher power settings. The purpose of this study was to determine if the increased lesion size during...

Paying attention to radiofrequency ablation therapy for neoplasms

International Nuclear Information System (INIS)

Wang Zhongming; Li Linsun

2010-01-01

Radiofrequency ablation is an effective treatment for malignant tumors. With the development of imaging technique, it has been widely used in treating different kinds of malignant tumors, such as liver cancer, lung cancer, kidney carcinoma, etc. Radiofrequency ablation has a lot of advantages. As a minimally-invasive, safe and effective treatment with less sufferings and fewer complications, this technique has attracted more and more attention of the experts both at home and abroad. (authors)

Radiofrequency for the treatment of skin laxity: mith or truth*

Science.gov (United States)

de Araújo, Angélica Rodrigues; Soares, Viviane Pinheiro Campos; da Silva, Fernanda Souza; Moreira, Tatiane da Silva

2015-01-01

The nonablative radiofrequency is a procedure commonly used for the treatment of skin laxity from an increase in tissue temperature. The goal is to induce thermal damage to thus stimulate neocollagenesis in deep layers of the skin and subcutaneous tissue. However, many of these devices haven't been tested and their parameters are still not accepted by the scientific community. Because of this, it is necessary to review the literature regarding the physiological effects and parameters for application of radiofrequency and methodological quality and level of evidence of studies. A literature search was performed in MEDLINE, PEDro, SciELO, PubMed, LILACS and CAPES and experimental studies in humans, which used radiofrequency devices as treatment for facial or body laxity, were selected. The results showed that the main physiological effect is to stimulate collagen synthesis. There was no homogeneity between studies in relation to most of the parameters used and the methodological quality of studies and level of evidence for using radiofrequency are low. This fact complicates the determination of effective parameters for clinical use of this device in the treatment of skin laxity. The analyzed studies suggest that radiofrequency is effective, however the physiological mechanisms and the required parameters are not clear in the literature. PMID:26560216

The biological effects of quadripolar radiofrequency sequential application: a human experimental study.

Science.gov (United States)

Nicoletti, Giovanni; Cornaglia, Antonia Icaro; Faga, Angela; Scevola, Silvia

2014-10-01

An experimental study was conducted to assess the effectiveness and safety of an innovative quadripolar variable electrode configuration radiofrequency device with objective measurements in an ex vivo and in vivo human experimental model. Nonablative radiofrequency applications are well-established anti-ageing procedures for cosmetic skin tightening. The study was performed in two steps: ex vivo and in vivo assessments. In the ex vivo assessments the radiofrequency applications were performed on human full-thickness skin and subcutaneous tissue specimens harvested during surgery for body contouring. In the in vivo assessments the applications were performed on two volunteer patients scheduled for body contouring surgery at the end of the study. The assessment methods were: clinical examination and medical photography, temperature measurement with thermal imaging scan, and light microscopy histological examination. The ex vivo assessments allowed for identification of the effective safety range for human application. The in vivo assessments allowed for demonstration of the biological effects of sequential radiofrequency applications. After a course of radiofrequency applications, the collagen fibers underwent an immediate heat-induced rearrangement and were partially denaturated and progressively metabolized by the macrophages. An overall thickening and spatial rearrangement was appreciated both in the collagen and elastic fibers, the latter displaying a juvenile reticular pattern. A late onset in the macrophage activation after sequential radiofrequency applications was appreciated. Our data confirm the effectiveness of sequential radiofrequency applications in obtaining attenuation of the skin wrinkles by an overall skin tightening.

One-year results of the use of endovenous radiofrequency ablation utilising an optimised radiofrequency-induced thermotherapy protocol for the treatment of truncal superficial venous reflux.

Science.gov (United States)

Badham, George E; Dos Santos, Scott J; Lloyd, Lucinda Ba; Holdstock, Judy M; Whiteley, Mark S

2018-06-01

Background In previous in vitro and ex vivo studies, we have shown increased thermal spread can be achieved with radiofrequency-induced thermotherapy when using a low power and slower, discontinuous pullback. We aimed to determine the clinical success rate of radiofrequency-induced thermotherapy using this optimised protocol for the treatment of superficial venous reflux in truncal veins. Methods Sixty-three patients were treated with radiofrequency-induced thermotherapy using the optimised protocol and were followed up after one year (mean 16.3 months). Thirty-five patients returned for audit, giving a response rate of 56%. Duplex ultrasonography was employed to check for truncal reflux and compared to initial scans. Results In the 35 patients studied, there were 48 legs, with 64 truncal veins treated by radiofrequency-induced thermotherapy (34 great saphenous, 15 small saphenous and 15 anterior accessory saphenous veins). One year post-treatment, complete closure of all previously refluxing truncal veins was demonstrated on ultrasound, giving a success rate of 100%. Conclusions Using a previously reported optimised, low power/slow pullback radiofrequency-induced thermotherapy protocol, we have shown it is possible to achieve a 100% ablation at one year. This compares favourably with results reported at one year post-procedure using the high power/fast pullback protocols that are currently recommended for this device.

Comparison of renal artery, soft tissue, and nerve damage after irrigated versus nonirrigated radiofrequency ablation.

Science.gov (United States)

Sakakura, Kenichi; Ladich, Elena; Fuimaono, Kristine; Grunewald, Debby; O'Fallon, Patrick; Spognardi, Anna-Maria; Markham, Peter; Otsuka, Fumiyuki; Yahagi, Kazuyuki; Shen, Kai; Kolodgie, Frank D; Joner, Michael; Virmani, Renu

2015-01-01

The long-term efficacy of radiofrequency ablation of renal autonomic nerves has been proven in nonrandomized studies. However, long-term safety of the renal artery (RA) is of concern. The aim of our study was to determine if cooling during radiofrequency ablation preserved the RA while allowing equivalent nerve damage. A total of 9 swine (18 RAs) were included, and allocated to irrigated radiofrequency (n=6 RAs, temperature setting: 50°C), conventional radiofrequency (n=6 RAs, nonirrigated, temperature setting: 65°C), and high-temperature radiofrequency (n=6 RAs, nonirrigated, temperature setting: 90°C) groups. RAs were harvested at 10 days, serially sectioned from proximal to distal including perirenal tissues and examined after paraffin embedding, and staining with hematoxylin-eosin and Movat pentachrome. RAs and periarterial tissue including nerves were semiquantitatively assessed and scored. A total of 660 histological sections from 18 RAs were histologically examined by light microscopy. Arterial medial injury was significantly less in the irrigated radiofrequency group (depth of medial injury, circumferential involvement, and thinning) than that in the conventional radiofrequency group (Pradiofrequency group (Pradiofrequency group and conventional radiofrequency group (P=0.36), there was a trend toward less nerve damage in the irrigated compared with conventional. Compared to conventional radiofrequency, circumferential medial damage in highest-temperature nonirrigated radiofrequency group was significantly greater (Pradiofrequency ablation, and there is a trend toward less nerve damage. © 2014 American Heart Association, Inc.

Electromagnetic field sources in radiofrequency

International Nuclear Information System (INIS)

Oliveira, C.; Sebastiao, D.; Ladeira, D.; Antunes, M.; Correia, L.M.

2010-01-01

In the scope of the monIT Project, several measurements were made of electromagnetic fields in Portugal. This paper presents an analysis of the sources operating in the radiofrequency range, resulting from 2429 measurements in 466 locations.

Parálisis cerebral :

OpenAIRE

Cabrero Izquierdo, María del Carmen

2012-01-01

Se aborda el tema de la parálisis cerebral definiendo qué es, clasificando los tipos de parálisis dependiendo de la afectación y las características principales. Se explican algunos de sus tratamientos, se dan sistemas alternativos y/o aumentativos de comunicación para un alumno con PC (parálisis cerebral).

[Catheter ablation in patients with refractory cardiac arrhythmias with radiofrequency techniques].

Science.gov (United States)

de Paola, A A; Balbão, C E; Silva Netto, O; Mendonça, A; Villacorta, H; Vattimo, A C; Souza, I A; Guiguer Júnior, N; Portugal, O P; Martinez Filho, E E

1993-02-01

evaluate the efficacy of radiofrequency catheter ablation in patients with refractory cardiac arrhythmias. twenty patients with refractory cardiac arrhythmias were undertaken to electrophysiologic studies for diagnosis and radiofrequency catheter ablation of their reentrant arrhythmias. Ten patients were men and 10 women with ages varying from 13 to 76 years (mean = 42.4 years). Nineteen patients had supraventricular tachyarrhythmias: One patient had atrial tachycardia and 1 atrial fibrillation with rapid ventricular rate, 5 patients had reentrant nodal tachycardia, 12 patients had reentrant atrioventricular tachycardia and 1 patient had right ventricular outflow tract tachycardia. the mean time of the procedure was 4.1 hours. The radiofrequency current energy applied was 40-50 V for 30-40 seconds. Ablation was successful in 18/20 (90%) patients; in 15/18 (83%) of successfully treated patients the same study was done for diagnosis and radiofrequency ablation. One patient had femoral arterial occlusion and was treated with no significant sequelae. During a mean follow-up of 4 months no preexcitation or reentrant tachycardia occurred. the results of our experience with radiofrequency catheter ablation of cardiac arrhythmias suggest that this technique can benefit an important number of patients with cardiac arrhythmias.

Radiofrequency ablation of hepatic metastasis: Results of treatment in forty patients

Directory of Open Access Journals (Sweden)

Rath G

2008-01-01

Full Text Available Aim: To evaluate the local control of hepatic metastasis with radiofrequency ablation treatment. Materials and Methods: We did a retrospective analysis in 40 patients treated with radiofrequency ablation for hepatic metastasis. The tumors ablated included up to two metastatic liver lesions, with primaries in breast, gastrointestinal tract, cervix, etc. Radiofrequency ablation was performed under general anesthesia in all cases, using ultrasound guidance. Radionics Cool-Tip RF System was used to deliver the treatment. Results: The median age of patients treated was 49 years. There were 13 female and 27 male patients. The median tumor size ablated was 1.5 cm (0.75-4.0 cm. A total of 52 radiofrequency ablation cycles were delivered. Successful ablation was achieved in all patients with hepatic metastasis less than 3 cm in size. Pain was the most common complication seen (75%. One patients developed skin burns. At 2-year follow-up 7.5% of patients had locally recurrent disease. Conclusions: Radiofrequency ablation is a minimally invasive treatment modality. It can be useful in a select group of patients with solitary liver metastasis of less than 3 cm size.

21 CFR 179.30 - Radiofrequency radiation for the heating of food, including microwave frequencies.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Radiofrequency radiation for the heating of food... PRODUCTION, PROCESSING AND HANDLING OF FOOD Radiation and Radiation Sources § 179.30 Radiofrequency radiation for the heating of food, including microwave frequencies. Radiofrequency radiation, including...

The safety and efficacy of a combined diode laser and bipolar radiofrequency compared with combined infrared light and bipolar radiofrequency for skin rejuvenation

Directory of Open Access Journals (Sweden)

Yeon Jin Choi

2012-01-01

Full Text Available Background: As the demand for noninvasive procedures for skin rejuvenation is increasing, combined diode laser and radiofrequency and combined infrared and radiofrequency devices have recently emerged. Aim: To compare Polaris WRA TM , a combination device of diode light and RF, and ReFirme ST TM , a combination device of infrared and bipolar RF, in terms of safety and efficacy on skin rejuvenation. Methods: Fourteen Korean volunteers of skin type II-IV, with facial laxity and periorbital rhytids, received three treatments at 3-week intervals with combined diode laser and bipolar radiofrequency (laser fluence 30 J/cm 2 , RF fluence 90 J/cm 3 on the right half of their faces and combined infrared light and bipolar radiofrequency (RF fluence 120 J/cm 3 on the left half of their faces. Clinical photos of front and bilateral sides of the subjects′ faces were taken at baseline and at 6, 9, 12 weeks after the treatment initiation. The investigators′ and the subjects′ global assessments were performed. Results: There is no statistically significant difference in the overall outcome between Polaris WRA TM and Refirme ST TM based on pre- and post-treatment objective measurements. Polaris WRA TM was more effective than Refirme ST TM at reducing wrinkles when therapeutic results of the two appliances were compared based on the patient satisfaction measurements. After the treatment with both instruments, histological increase in the production and rearrangement of collagen fibers at the dermal layer was observed. The density of the collagen fibers was more increased with the Polaris WRA TM -treated facial area than that of Refirme ST TM . Treatment was generally well tolerated, and there was no serious complication. Conclusion: In this study, both the lasers appeared to be safe, and effective methods for treating skin laxity and facial wrinkles. Combined diode laser and radiofrequency was more effective than combined infrared and radiofrequency at

The safety and efficacy of a combined diode laser and bipolar radiofrequency compared with combined infrared light and bipolar radiofrequency for skin rejuvenation.

Science.gov (United States)

Choi, Yeon Jin; Lee, Jung Yeon; Ahn, Ji Young; Kim, Myeung Nam; Park, Mi Youn

2012-01-01

As the demand for noninvasive procedures for skin rejuvenation is increasing, combined diode laser and radiofrequency and combined infrared and radiofrequency devices have recently emerged. To compare Polaris WRA(TM), a combination device of diode light and RF, and ReFirme ST(TM), a combination device of infrared and bipolar RF, in terms of safety and efficacy on skin rejuvenation. Fourteen Korean volunteers of skin type II-IV, with facial laxity and periorbital rhytids, received three treatments at 3-week intervals with combined diode laser and bipolar radiofrequency (laser fluence 30 J/cm2, RF fluence 90 J/cm3) on the right half of their faces and combined infrared light and bipolar radiofrequency (RF fluence 120 J/cm3) on the left half of their faces. Clinical photos of front and bilateral sides of the subjects' faces were taken at baseline and at 6, 9, 12 weeks after the treatment initiation. The investigators' and the subjects' global assessments were performed. There is no statistically significant difference in the overall outcome between Polaris WRA(TM) and Refirme ST(TM) based on pre- and post-treatment objective measurements. Polaris WRA(TM) was more effective than Refirme ST(TM) at reducing wrinkles when therapeutic results of the two appliances were compared based on the patient satisfaction measurements. After the treatment with both instruments, histological increase in the production and rearrangement of collagen fibers at the dermal layer was observed. The density of the collagen fibers was more increased with the Polaris WRA(TM)-treated facial area than that of Refirme ST(TM). Treatment was generally well tolerated, and there was no serious complication. In this study, both the lasers appeared to be safe, and effective methods for treating skin laxity and facial wrinkles. Combined diode laser and radiofrequency was more effective than combined infrared and radiofrequency at reducing wrinkles and pores when the therapeutic results of both the

12-month efficacy of a single radiofrequency ablation on autonomously functioning thyroid nodules.

Science.gov (United States)

Bernardi, Stella; Stacul, Fulvio; Michelli, Andrea; Giudici, Fabiola; Zuolo, Giulia; de Manzini, Nicolò; Dobrinja, Chiara; Zanconati, Fabrizio; Fabris, Bruno

2017-09-01

Radiofrequency ablation has been advocated as an alternative to radioiodine and/or surgery for the treatment of autonomously functioning benign thyroid nodules. However, only a few studies have measured radiofrequency ablation efficacy on autonomously functioning benign thyroid nodules. The aim of this work was to evaluate the 12-month efficacy of a single session of radiofrequency ablation (performed with the moving shot technique) on solitary autonomously functioning benign thyroid nodules. Thirty patients with a single, benign autonomously functioning benign thyroid nodules, who were either unwilling or ineligible to undergo surgery and radioiodine, were treated with radiofrequency ablation between April 2012 and May 2015. All the patients underwent a single radiofrequency ablation, performed with the 18-gauge needle and the moving shot technique. Clinical, laboratory, and ultrasound evaluations were scheduled at baseline, and after 1, 3, 6, and 12 months from the procedure. A single radiofrequency ablation reduced thyroid nodule volume by 51, 63, 69, and 75 % after 1, 3, 6, and 12 months, respectively. This was associated with a significant improvement of local cervical discomfort and cosmetic score. As for thyroid function, 33 % of the patients went into remission after 3 months, 43 % after 6 months, and 50 % after 12 months from the procedure. This study demonstrates that a single radiofrequency ablation allowed us to withdraw anti-thyroid medication in 50 % of the patients, who remained euthyroid afterwards. This study shows that a single radiofrequency ablation was effective in 50 % of patients with autonomously functioning benign thyroid nodules. Patients responded gradually to the treatment. It is possible that longer follow-up studies might show greater response rates.

WORKSHOP: Radiofrequency superconductivity

Energy Technology Data Exchange (ETDEWEB)

Anon.

1984-10-15

The Second Workshop on Radiofrequency Superconductivity was held at CERN from 23-27 July, four years after the first, organized at Karlsruhe. 35 invited talks were presented to the about 80 participants from Australia, Brazil, Europe, Japan and the United States. For the first time, ten Laboratories operating or planning superconducting accelerators for heavy ions participated and shared their experience with the community proposing the use of superconducting accelerating sections for electron accelerators.

WORKSHOP: Radiofrequency superconductivity

International Nuclear Information System (INIS)

Anon.

1984-01-01

The Second Workshop on Radiofrequency Superconductivity was held at CERN from 23-27 July, four years after the first, organized at Karlsruhe. 35 invited talks were presented to the about 80 participants from Australia, Brazil, Europe, Japan and the United States. For the first time, ten Laboratories operating or planning superconducting accelerators for heavy ions participated and shared their experience with the community proposing the use of superconducting accelerating sections for electron accelerators

Novel role for proteinase-activated receptor 2 (PAR2) in membrane trafficking of proteinase-activated receptor 4 (PAR4).

Science.gov (United States)

Cunningham, Margaret R; McIntosh, Kathryn A; Pediani, John D; Robben, Joris; Cooke, Alexandra E; Nilsson, Mary; Gould, Gwyn W; Mundell, Stuart; Milligan, Graeme; Plevin, Robin

2012-05-11

Proteinase-activated receptors 4 (PAR(4)) is a class A G protein-coupled receptor (GPCR) recognized through the ability of serine proteases such as thrombin and trypsin to mediate receptor activation. Due to the irreversible nature of activation, a fresh supply of receptor is required to be mobilized to the cell surface for responsiveness to agonist to be sustained. Unlike other PAR subtypes, the mechanisms regulating receptor trafficking of PAR(4) remain unknown. Here, we report novel features of the intracellular trafficking of PAR(4) to the plasma membrane. PAR(4) was poorly expressed at the plasma membrane and largely retained in the endoplasmic reticulum (ER) in a complex with the COPI protein subunit β-COP1. Analysis of the PAR(4) protein sequence identified an arginine-based (RXR) ER retention sequence located within intracellular loop-2 (R(183)AR → A(183)AA), mutation of which allowed efficient membrane delivery of PAR(4). Interestingly, co-expression with PAR(2) facilitated plasma membrane delivery of PAR(4), an effect produced through disruption of β-COP1 binding and facilitation of interaction with the chaperone protein 14-3-3ζ. Intermolecular FRET studies confirmed heterodimerization between PAR(2) and PAR(4). PAR(2) also enhanced glycosylation of PAR(4) and activation of PAR(4) signaling. Our results identify a novel regulatory role for PAR(2) in the anterograde traffic of PAR(4). PAR(2) was shown to both facilitate and abrogate protein interactions with PAR(4), impacting upon receptor localization and cell signal transduction. This work is likely to impact markedly upon the understanding of the receptor pharmacology of PAR(4) in normal physiology and disease.

Bipolar Radiofrequency Facet Ablation of the Lumbar Facet Capsule: An Adjunct to Conventional Radiofrequency Ablation for Pain Management.

Science.gov (United States)

Jacobson, Robert E; Palea, Ovidiu; Granville, Michelle

2017-09-01

Radiofrequency facet ablation (RFA) has been performed using the same technique for over 50 years. Except for variations in electrode size, tip shape, and change in radiofrequency (RF) stimulation parameters, using standard, pulsed, and cooled RF wavelengths, the target points have remained absolutely unchanged from the original work describing RFA for lumbar pain control. Degenerative changes in the facet joint and capsule are the primary location for the majority of lumbar segmental pathology and pain. Multiple studies show that the degenerated facet joint is richly innervated as a result of the inflammatory overgrowth of the synovium. The primary provocative clinical test to justify an RFA is to perform an injection with local anesthetic into the facet joint and the posterior capsule and confirm pain relief. However, after a positive response, the radiofrequency lesion is made not to the facet joint but to the more proximal fine nerve branches that innervate the joint. The accepted target points for the recurrent sensory branch ignore the characteristic rich innervation of the pathologic lumbar facet capsule and assume that lesioning of these recurrent branches is sufficient to denervate the painful pathologic facet joint. This report describes the additional targets and technical steps for further coagulation points along the posterior capsule of the lumbar facet joint and the physiologic studies of the advantage of the bipolar radiofrequency current in this location. Bipolar RF to the facet capsule is a simple, extra step that easily creates a large thermo-coagulated lesion in this capsule region of the pathologic facet joint. Early studies demonstrate bipolar RF to the facet capsule can provide long-term pain relief when used alone for specific localized facet joint pain, to coagulate lumbar facet cysts to prevent recurrence, and to get more extensive pain control by combining it with traditional lumbar RFA, especially when RFA is repeated.

A New Radiofrequency Ablation Procedure to Treat Sacroiliac Joint Pain.

Science.gov (United States)

Cheng, Jianguo; Chen, See Loong; Zimmerman, Nicole; Dalton, Jarrod E; LaSalle, Garret; Rosenquist, Richard

2016-01-01

Low back pain may arise from disorders of the sacroiliac joint in up to 30% of patients. Radiofrequency ablation (RFA) of the nerves innervating the sacroiliac joint has been shown to be a safe and efficacious strategy. We aimed to develop a new RFA technique to relieve low back pain secondary to sacroiliac joint disorders. Methodology development with validation through prospective observational non-randomized trial (PONRT). Academic multidisciplinary health care system, Ohio, USA. We devised a guide-block to facilitate accurate placement of multiple electrodes to simultaneously ablate the L5 dorsal ramus and lateral branches of the S1, S2, and S3 dorsal rami. This was achieved by bipolar radiofrequency ablation (b-RFA) to create a strip lesion from the lateral border of the base of the sacral superior articular process (L5-S1 facet joint) to the lateral border of the S3 sacral foramen. We applied this technique in 31 consecutive patients and compared the operating time, x-ray exposure time and dose, and clinical outcomes with patients (n = 62) who have been treated with the cooled radiofrequency technique. Patients' level of pain relief was reported as 80% pain relief at one, 3, 6, and 12 months after the procedure. The relationship between RFA technique and duration of pain relief was evaluated using interval-censored multivariable Cox regression. The new technique allowed reduction of operating time by more than 50%, x-ray exposure time and dose by more than 80%, and cost by more than $1,000 per case. The percent of patients who achieved > 50% pain reduction was significantly higher in the b-RFA group at 3, 6, and 12 months follow-up, compared to the cooled radiofrequency group. No complications were observed in either group. Although the major confounding factors were taken into account in the analysis, use of historical controls does not balance observed and unobserved potential confounding variables between groups so that the reported results are potentially

Cooling system for the IFMIF-EVEDA radiofrequency system

International Nuclear Information System (INIS)

Perez Pichel, G. D.

2012-01-01

The IFMIF-EVEDA project consists on an accelerator prototype that will be installed at Rokkasho (Japan). Through CIEMAT, that is responsible of the development of many systems and components. Empresarios Agrupados get the responsibility of the detailed design of the cooling system for the radiofrequency system (RF system) that must feed the accelerator. the RF water cooling systems is the water primary circuit that provides the required water flow (with a certain temperature, pressure and water quality) and also dissipates the necessary thermal power of all the radiofrequency system equipment. (Author) 4 refs.

Fraxelated radiofrequency device for acne scars

Science.gov (United States)

Rao, Babar K.; Khokher, Sairah

2012-09-01

Acne scars can be improved with various treatments such as topical creams, chemical peels, dermal fillers, microdermabrasion, laser, and radiofrequency devices. Some of these treatments especially lasers and deep chemical peels can have significant side effects such as post inflammatory hyperpigmentation in darker skin types. Fraxelated RF Laser devices have been reported to have lower incidence of side effects in all skin phototypes. Nine patients between ages 18 and 35 of various skin phototypes were selected from a private practice and treated with a RF fraxelated device (E-matrix) for acne scars. Outcomes were measured by physician observation, subjective feedback received by patients, and comparison of before and after photographs. In this small group of patients with various skin phototypes, fraxelated radiofrequency device improved acne scars with minimal side effects and downtime.

Arthroscopic surgery using radio-frequency electrocautery

International Nuclear Information System (INIS)

Takatsuka, Shigeyuki; Yoshida, Kan; Nakagawa, Kiyomasa; Yamamoto, Etsuhide; Kubota, Yoshiyuki; Narinobou, Masayoshi; Terai, Koichi; Hasegawa, Hiroshi

2008-01-01

Arthroscopic surgery using radio-frequency electrocautery was carried out on 23 temporomandibular joints (TMJs) in 13 patients. Because these patients did not respond to conservative therapy, surgery was indicated. Preoperative MRI showed anterior disc displacement without reduction in all patients. Disturbed translation was also recognized in all of the discs and mandibular condyles. Intraoperative arthroscopic examination showed severe fibrous adhesion in the upper joint compartment and disc displacement. Four joints showed perforation between the disc and retrodiscal tissue. Postoperative findings included an increased range of vertical maximal mouth opening and decreased pain on mandibular movement. Analyses of postoperative MRI indicated recovery of disc and condylar translation. These results suggested that the introduction of arthroscopic surgery using radiofrequency electrocautery would significantly reduce the number of patients with osteoarthritic TMJ disorders. (author)

Transurethral radiofrequency collagen denaturation for the treatment of women with urinary incontinence.

Science.gov (United States)

Kang, Diana; Han, Julia; Neuberger, Molly M; Moy, M Louis; Wallace, Sheila A; Alonso-Coello, Pablo; Dahm, Philipp

2015-03-18

Transurethral radiofrequency collagen denaturation is a relatively novel, minimally invasive device-based intervention used to treat individuals with urinary incontinence (UI). No systematic review of the evidence supporting its use has been published to date. To evaluate the efficacy of transurethral radiofrequency collagen denaturation, compared with other interventions, in the treatment of women with UI.Review authors sought to compare the following.• Transurethral radiofrequency collagen denaturation versus no treatment/sham treatment.• Transurethral radiofrequency collagen denaturation versus conservative physical treatment.• Transurethral radiofrequency collagen denaturation versus mechanical devices (pessaries for UI).• Transurethral radiofrequency collagen denaturation versus drug treatment.• Transurethral radiofrequency collagen denaturation versus injectable treatment for UI.• Transurethral radiofrequency collagen denaturation versus other surgery for UI. We conducted a systematic search of the Cochrane Incontinence Group Specialised Register (searched 19 December 2014), EMBASE and EMBASE Classic (January 1947 to 2014 Week 50), Google Scholar and three trials registries in December 2014, along with reference checking. We sought to identify unpublished studies by handsearching abstracts of major gynaecology and urology meetings, and by contacting experts in the field and the device manufacturer. Randomised and quasi-randomised trials of transurethral radiofrequency collagen denaturation versus no treatment/sham treatment, conservative physical treatment, mechanical devices, drug treatment, injectable treatment for UI or other surgery for UI in women were eligible. We screened search results and selected eligible studies for inclusion. We assessed risk of bias and analysed dichotomous variables as risk ratios (RRs) with 95% confidence intervals (CIs) and continuous variables as mean differences (MDs) with 95% CIs. We rated the quality of

Ion collection from laser-induced plasma by applying radio-frequency voltage

International Nuclear Information System (INIS)

Shibata, Takemasa; Ogura, Koichi

1995-01-01

Ions were collected on the electrodes from a laser resonance photoionized plasma by applying 1.8MHz radio-frequency voltage to the electrode. It was demonstrated that the ions are collected in a shorter time at the same kinetic energy of the collected ions compared with ion collection by applying DC voltage to the electrode. A simple one-dimensional model was extended for prediction of ion collection times in the cases of applications of not only the DC voltage but also the radio-frequency voltage. The ion collection times estimated using the simple one-dimensional model agreed with experimental values in both cases of DC and radio-frequency voltages. (author)

Effect of Radiofrequency Endometrial Ablation on Dysmenorrhea.

Science.gov (United States)

Wyatt, Sabrina N; Banahan, Taylor; Tang, Ying; Nadendla, Kavita; Szychowski, Jeff M; Jenkins, Todd R

To examine rates of dysmenorrhea after radiofrequency endometrial ablation in patients with and without known dysmenorrhea symptoms prior to the procedure in a diverse population. Retrospective cohort study (Canadian Task Force classification II-2). Academic gynecology practice. A total of 307 women underwent endometrial ablation between 2007 and 2013 at our institution. Patients who had preoperative and postoperative pain symptom assessments as well as a description of pain timing recorded were included in our analysis. Exclusion criteria were age dysmenorrhea was evaluated. Demographic information and other outcome variables were used to evaluate factors associated with resolution of dysmenorrhea. A total of 307 patients who underwent radiofrequency endometrial ablation were identified. After exclusions, 296 charts were examined, and 144 patients met our enrollment criteria. The mean age of the study cohort was 45.4 ± 6.2 years; 57 patients (40%) were African American, 16 (11%) had a body mass index (BMI) > 40, and 41 (29%) were of normal weight. Preoperative dysmenorrhea was reported by 100 patients (69%); 48 of these patients (48%) experienced resolution of symptoms postoperatively. Only 3 of the 44 patients (7%) without preoperative dysmenorrhea reported new-onset dysmenorrhea postoperatively. Significantly fewer patients had dysmenorrhea after compared to before radiofrequency ablation (55 of 144 [38%] vs 100 of 144 [69%]; p dysmenorrhea after ablation was associated with reduction in bleeding volume (p = .048) but not with a reduction in frequency of bleeding (p = .12). Approximately one-half of women who undergo radiofrequency endometrial ablation to treat heavy menstrual bleeding who also have preoperative dysmenorrhea exhibit documented pain resolution after the procedure. Resolution of dysmenorrhea is more likely if menstrual flow volume is decreased postprocedure. Copyright © 2016 AAGL. Published by Elsevier Inc. All rights reserved.

Radiofrequency Ablation Effectively Treated Focal Recurrence of Mesothelioma.

Science.gov (United States)

Nakamura, Akifumi; Takuwa, Teruhisa; Hashimoto, Masaki; Kondo, Nobuyuki; Takaki, Haruyuki; Fujiwara, Masayuki; Yamakado, Koichiro; Hasegawa, Seiki

2018-02-01

A 55-year-old man with malignant pleural mesothelioma underwent multimodality treatment comprising induction chemotherapy followed by extrapleural pneumonectomy and radiation therapy. After 2.5 years, focal recurrence occurred, with computed tomography revealing a tumor in the left cardiophrenic angle. Surgery was considered a problem for the patient because of the previous extrapleural pneumonectomy and difficult tumor location. Radiofrequency ablation was thus performed; the course was uneventful, and there was no recurrence. Radiofrequency ablation should be considered an option to treat recurrence of malignant pleural mesothelioma. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Endoscopic ultrasound-guided radiofrequency ablation of the pancreas

DEFF Research Database (Denmark)

Silviu, Ungureanu Bogdan; Daniel, Pirici; Claudiu, Mărgăritescu

2015-01-01

ultrasound (EUS)-guided radiofrequency ablation (RFA) probe through a 19G needle in order to achieve a desirable necrosis area in the pancreas. Radiofrequency ablation of the head of the pancreas was performed on 10 Yorkshire pigs with a weight between 25 kg and 35 kg and a length of 40-70 cm. Using an EUS...... analysis revealed increased values of amylase, alkaline phosphatase, and gamma-glutamyl transpeptidase on the 3rd day but a decrease on the 5th day. After necropsy and isolation of the pancreas, the ablated area was easily found, describing a solid necrosis. The pathological examination revealed...

Neuronavigator-guided percutaneous radiofrequency thermocoagulation in the treatment of trigeminal neuralgia.

Science.gov (United States)

Zhang, W C; Zhong, W X; Li, S T; Zheng, X S; Yang, M; Shi, J

2012-03-01

Although radiofrequency thermocoagulation is considered as a primary treatment for most patients with trigeminal neuralgia, neuronavigator-guided percutaneous radiofrequency thermocoagulation has been rarely reported. The object of this study was to assess the clinical value of neuronavigator-guided percutaneous radiofrequency thermocoagulation in the treatment of trigeminal neuralgia. The radiofrequency thermocoagulation was performed in 100 cases of trigeminal neuralgia. The patients were positioned supine or sitting, under Hartel's technique (reported by Sweet and Wepsic J Neurosurg 40:143-156, 1974), by anterior lateral facial approaches. The Gasserian ganglions were acupunctured, assisted by intraoperative CT scanning (3-digital reconstruction) and electrophysiology in order to accurately locate target. The needles located in oval foramen at the first puncture, the direction and position could be defined according to the electrophysiology examination. The pain alleviated immediately after operation. There occurred no serious complication and other nerve injury in all patients despite face numbness only. 3D-CT and electrophysiology Gasser's ganglion locations can raise the success rate of puncture, enhance the safety and reduce the incidence of complication, showing high academic value and its promising future.

Par Pond vegetation status 1996

International Nuclear Information System (INIS)

Mackey, H.E. Jr.; Riley, R.S.

1996-12-01

The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the newly emergent, shoreline aquatic plant communities of Par Pond began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level. These surveys continued in July, September, and late October, 1995, and into the early spring and late summer of 1996. Communities similar to the pre-drawdown, Par Pond aquatic plant communities continue to become re-established. Emergent beds of maidencane, lotus, waterlily, watershield, and Pontederia are extensive and well developed. Measures of percent cover, width of beds, and estimates of area of coverage with satellite data indicate regrowth within two years of from 40 to 60% of levels prior to the draw down. Cattail occurrence continued to increase during the summer of 1996, especially in the former warm arm of Par Pond, but large beds common to Par Pond prior to the draw down still have not formed. Lotus has invaded and occupies many of the areas formerly dominated by cattail beds. To track the continued development of macrophytes in Par Pond, future surveys through the summer and early fall of 1997, along with the evaluation of satellite data to map the extent of the macrophyte beds of Par Pond, are planned

Feasibility of Noninvasive Temperature Assessment During Radiofrequency Liver Ablation on Computed Tomography

NARCIS (Netherlands)

Pandeya, Ganga D.; Greuter, Marcel J. W.; de Jong, Koert P.; Schmidt, Bernhard; Flohr, Thomas; Oudkerk, Matthijs

2011-01-01

Purpose: The purpose of this study was to assess the feasibility of noninvasive thermometry using high-resolution computer tomography (CT) for the monitoring of bovine liver during radiofrequency (RF) ablation. Methods: Radiofrequency probes were used to ablate bovine livers from 20 degrees C to 98

Ophthalmic branch radiofrequency thermocoagulation for atypical trigeminal neuralgia:a case report.

Science.gov (United States)

Du, Shibin; Ma, Xiaoliang; Li, Xiaoqin; Yuan, Hongjie

2015-01-01

Trigeminal neuralgia is an intense neuralgia involving facial areas supplied by trigeminal nerve. The pain is characterized by sudden onset, short persistence, sharp or lancinating. Trigeminal neuralgia commonly affects frontal areas, infraorbital or paranasal areas, mandibular areas and teeth. While Trigeminal neuralgia affecting merely the upper eyelid is rare. Here we report a case of atypical Trigeminal neuralgia confined to the upper eyelid. The patient was pain free during the follow-up period of 6 months after unusual ophthalmic branch radiofrequency thermocoagulation. A 55-year-old female patient was diagnosed as primary trigeminal neuralgia involving the right upper eyelid. As the pain could not be controlled by drug therapy, peripheral nerve branch radiofrequency thermocoagulation was recommended. A combination of infratrochlear, supratrochlear and lacrimal radiofrequency thermocoagulation was implemented in this case. The point where the bridge of the nose abuts the supraorbital ridge and the point slightly above the lateral canthus along outer border of the orbit were selected respectively as the puncture sites. After positive diagnostic test, radiofrequency thermocoagulation of the above-mentioned nerve branches was performed respectively. The patient was pain free immediately after the treatment and during the follow-up period of 6 months. Trigeminal neuralgia is a common severe and chronic facial neuralgia which requires accurate diagnosis and effective therapy. With typical clinical symptoms, normal neurological signs, normal CT and MRI findings, the patient was diagnosed as classic trigeminal neuralgia. As the patient was drug resistant, some invasive treatments were considered. Peripheral branch neurolysis was chosen for its minimal invasiveness, convenience, low risk and not affecting further invasive treatments. According to the anatomic data and the diagnostic test results, infratrochlear, supratrochlear and lacrimal nerve were responsible

Sphenopalatine ganglion: block, radiofrequency ablation and neurostimulation - a systematic review.

Science.gov (United States)

Ho, Kwo Wei David; Przkora, Rene; Kumar, Sanjeev

2017-12-28

Sphenopalatine ganglion is the largest collection of neurons in the calvarium outside of the brain. Over the past century, it has been a target for interventional treatment of head and facial pain due to its ease of access. Block, radiofrequency ablation, and neurostimulation have all been applied to treat a myriad of painful syndromes. Despite the routine use of these interventions, the literature supporting their use has not been systematically summarized. This systematic review aims to collect and summarize the level of evidence supporting the use of sphenopalatine ganglion block, radiofrequency ablation and neurostimulation. Medline, Google Scholar, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases were reviewed for studies on sphenopalatine ganglion block, radiofrequency ablation and neurostimulation. Studies included in this review were compiled and analyzed for their treated medical conditions, study design, outcomes and procedural details. Studies were graded using Oxford Center for Evidence-Based Medicine for level of evidence. Based on the level of evidence, grades of recommendations are provided for each intervention and its associated medical conditions. Eighty-three publications were included in this review, of which 60 were studies on sphenopalatine ganglion block, 15 were on radiofrequency ablation, and 8 were on neurostimulation. Of all the studies, 23 have evidence level above case series. Of the 23 studies, 19 were on sphenopalatine ganglion block, 1 study on radiofrequency ablation, and 3 studies on neurostimulation. The rest of the available literature was case reports and case series. The strongest evidence lies in using sphenopalatine ganglion block, radiofrequency ablation and neurostimulation for cluster headache. Sphenopalatine ganglion block also has evidence in treating trigeminal neuralgia, migraines, reducing the needs of analgesics after endoscopic sinus surgery and reducing pain associated with nasal packing

Cooled radiofrequency denervation for treatment of sacroiliac joint pain: two-year results from 20 cases

Science.gov (United States)

Ho, Kok-Yuen; Hadi, Mohamed Abdul; Pasutharnchat, Koravee; Tan, Kian-Hian

2013-01-01

Background Sacroiliac joint pain is a common cause of chronic low back pain. Different techniques for radiofrequency denervation of the sacroiliac joint have been used to treat this condition. However, results have been inconsistent because the variable sensory supply to the sacroiliac joint is difficult to disrupt completely using conventional radiofrequency. Cooled radiofrequency is a novel technique that uses internally cooled radiofrequency probes to enlarge lesion size, thereby increasing the chance of completely denervating the sacroiliac joint. The objective of this study was to evaluate the efficacy of cooled radiofrequency denervation using the SInergy™ cooled radiofrequency system for sacroiliac joint pain. Methods The charts of 20 patients with chronic sacroiliac joint pain who had undergone denervation using the SInergy™ cooled radiofrequency system were reviewed at two years following the procedure. Outcome measures included the Numeric Rating Scale for pain intensity, Patient Global Impression of Change, and Global Perceived Effect for patient satisfaction. Results Fifteen of 20 patients showed a significant reduction in pain (a decrease of at least three points on the Numeric Rating Scale). Mean Numeric Rating Scale for pain decreased from 7.4 ± 1.4 to 3.1 ± 2.5, mean Patient Global Impression of Change was “improved” (1.4 ± 1.5), and Global Perceived Effect was reported to be positive in 16 patients at two years following the procedure. Conclusion Cooled radiofrequency denervation showed long-term efficacy for up to two years in the treatment of sacroiliac joint pain. PMID:23869175

Combination acetabular radiofrequency ablation and cementoplasty using a navigational radiofrequency ablation device and ultrahigh viscosity cement: technical note.

Science.gov (United States)

Wallace, Adam N; Huang, Ambrose J; Vaswani, Devin; Chang, Randy O; Jennings, Jack W

2016-03-01

Percutaneous radiofrequency ablation and cementoplasty is an alternative palliative therapy for painful metastases involving axial load-bearing bones. This technical report describes the use of a navigational radiofrequency probe to ablate acetabular metastases from an anterior approach followed by instillation of ultrahigh viscosity cement under CT-fluoroscopic guidance. The tumor ablation databases of two institutions were retrospectively reviewed to identify patients who underwent combination acetabular radiofrequency ablation and cementoplasty using the STAR Tumor Ablation and StabiliT Vertebral Augmentation Systems (DFINE; San Jose, CA). Pre-procedure acetabular tumor volume was measured on cross-sectional imaging. Pre- and post-procedure pain scores were measured using the Numeric Rating Scale (10-point scale) and compared. Partial pain improvement was categorically defined as ≥ 2-point pain score reduction. Patients were evaluated for evidence of immediate complications. Electronic medical records were reviewed for evidence of delayed complications. During the study period, 12 patients with acetabular metastases were treated. The median tumor volume was 54.3 mL (range, 28.3-109.8 mL). Pre- and post-procedure pain scores were obtained from 92% (11/12) of the cohort. The median pre-procedure pain score was 8 (range, 3-10). Post-procedure pain scores were obtained 7 days (82%; 9/11), 11 days (9.1%; 1/11) or 21 days (9.1%; 1/11) after treatment. The median post-treatment pain score was 3 (range, 1-8), a statistically significant difference compared with pre-treatment (P = 0.002). Categorically, 73% (8/11) of patients reported partial pain relief after treatment. No immediate symptomatic complications occurred. Three patients (25%; 3/12) were discharged to hospice within 1 week of treatment. No delayed complications occurred in the remaining 75% (9/12) of patients during median clinical follow-up of 62 days (range, 14-178 days). Palliative percutaneous

Osteoid osteoma of the spine: CT-guided monopolar radiofrequency ablation

Energy Technology Data Exchange (ETDEWEB)

Martel, Jose [Departamento de Diagnostico por Imagen, Fundacion Hospital Alcorcon, Alcorcon, Madrid (Spain)], E-mail: jmartel@fhalcorcon.es; Bueno, Angel [Departamento de Diagnostico por Imagen, Fundacion Hospital Alcorcon, Alcorcon, Madrid (Spain); Nieto-Morales, M Luisa [Servicio de Radiologia, Hospital Universitario de Tenerife (Spain); Ortiz, Eduardo J. [Departamento de Cirugia Ortopedica, Fundacion Hospital Alcorcon, Alcorcon, Madrid (Spain)

2009-09-15

CT-guided percutaneous radiofrequency ablation and laser photocoagulation have become the methods of choice for the treatment of all osteoid osteomas except those in contact with neural structures. We report 10 patients with spinal osteoid osteoma adjacent to the neural elements treated with 12 sessions of CT-guided monopolar radiofrequency ablation. The size range of the lesion was 3-14 mm (mean, 7.5 mm) and the distance between the nidus and the adjacent spinal cord or nerve root was 2-12 mm (mean, 5 mm). No intact cortex between the tumor and the spinal cord or nerve roots constituted an exclusion criterion because of a higher risk of undesirable neurotoxic effects. Patients were under general anesthesia. After location of the lesion, a 11G-bone biopsy was introduced into the nidus. The radiofrequency electrode was inserted through the biopsy needle and heated at 90 deg. C for 4 min. Primary success was obtained in eight patients. At follow-up (mean, 19.5 months; range, 6-24 months), pain persisted in two patients after 2 months. Both of them were re-treated. All patients are currently pain-free and complications were not detected. In our opinion, radiofrequency ablation can also be considered the treatment of choice for spinal osteoid osteoma.

Long-wave plasma radiofrequency ablation for treatment of xanthelasma palpebrarum.

Science.gov (United States)

Baroni, Adone

2018-03-01

Xanthelasma palpebrarum is the most common type of xanthoma affecting the eyelids. It is characterized by asymptomatic soft yellowish macules, papules, or plaques over the upper and lower eyelids. Many treatments are available for management of xanthelasma palpebrarum, the most commonly used include surgical excision, ablative CO 2 or erbium lasers, nonablative Q-switched Nd:YAG laser, trichloroacetic acid peeling, and radiofrequency ablation. This study aims to evaluate the effectiveness of RF ablation in the treatment of xanthelasma palpebrarum, with D.A.S. Medical portable device (Technolux, Italia), a radiofrequency tool working with long-wave plasma energy and without anesthesia. Twenty patients, 15 female and 5 male, affected by xanthelasma palpebrarum, were enrolled for long-wave plasma radiofrequency ablation treatment. The treatment consisted of 3/4 sessions that were carried out at intervals of 30 days. Treatments were well tolerated by all patients with no adverse effects and optimal aesthetic results. The procedure is very fast and can be performed without anesthesia because of the low and tolerable pain stimulation. Long-wave plasma radiofrequency ablation is an effective option for treatment of xanthelasma palpebrarum and adds an additional tool to the increasing list of medical devices for aesthetic treatments. © 2018 Wiley Periodicals, Inc.

Osteoid osteoma of the spine: CT-guided monopolar radiofrequency ablation

International Nuclear Information System (INIS)

Martel, Jose; Bueno, Angel; Nieto-Morales, M Luisa; Ortiz, Eduardo J.

2009-01-01

CT-guided percutaneous radiofrequency ablation and laser photocoagulation have become the methods of choice for the treatment of all osteoid osteomas except those in contact with neural structures. We report 10 patients with spinal osteoid osteoma adjacent to the neural elements treated with 12 sessions of CT-guided monopolar radiofrequency ablation. The size range of the lesion was 3-14 mm (mean, 7.5 mm) and the distance between the nidus and the adjacent spinal cord or nerve root was 2-12 mm (mean, 5 mm). No intact cortex between the tumor and the spinal cord or nerve roots constituted an exclusion criterion because of a higher risk of undesirable neurotoxic effects. Patients were under general anesthesia. After location of the lesion, a 11G-bone biopsy was introduced into the nidus. The radiofrequency electrode was inserted through the biopsy needle and heated at 90 deg. C for 4 min. Primary success was obtained in eight patients. At follow-up (mean, 19.5 months; range, 6-24 months), pain persisted in two patients after 2 months. Both of them were re-treated. All patients are currently pain-free and complications were not detected. In our opinion, radiofrequency ablation can also be considered the treatment of choice for spinal osteoid osteoma.

Radiofrequency energy in the arthroscopic treatment of knee chondral lesions: a systematic review.

Science.gov (United States)

Rocco, Papalia; Lorenzo, Diaz Balzani; Guglielmo, Torre; Michele, Paciotti; Nicola, Maffulli; Vincenzo, Denaro

2016-03-01

Cartilage debridement is one of the recommended procedures for the management of chondral defects. Radiofrequency probes allow to debride the cartilage, but may induce subchondral bone necrosis. Medline, Cochrane and Google Scholar were searched to identify studies on arthroscopic debridement of the articular cartilage of the knee using radiofrequency chondroplasty. The methodological quality of the studies was assessed using the Coleman methodology score (CMS). Monopolar and bipolar radiofrequency devices provide significantly better clinical outcomes, especially for patients with high-grade chondral lesions, compared with mechanical shaver only. Despite the original concerns regarding subchondral bone necrosis, low complication rates are reported. Heterogeneity in terms of type of device does not allow sound comparison of the published results. There is lack of evidence on the long-term effects of radiofrequency chondroplasty. Study methodology should be improved: the average Coleman methodology score was 56.2 out of 100. More comparative, well-designed and larger cohort trials are needed to ascertain whether radiofrequency chondroplasty offers long-term benefits over other simpler and more economical alternatives. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Ultrasound-guided radiofrequency ablation of thyroid gland: a preliminary study in dogs

International Nuclear Information System (INIS)

Choi, Ji Won; Yoo, Seung Min; Kwak, Seo Hyun

2005-01-01

The purpose of this study was to evaluate the possibility of using radiofrequency ablation as the treatment modality for the benign or malignant thyroid nodules in humans. Therefore, we examined the results of using radiofrequency ablation on the thyroid glands in dogs, in respect of the extent of the ablated tissue and the complications. Five dogs (10 lobes of the thyroid glands) were included in this study. US-guided radiofrequency ablation was undertaken with a 10 mm, uncovered 17 gauge cool-tip needle. The power and duration was 20 wattage and 1 minute in five thyroid lobes (group 1) and 20 wattage and 2 minutes in another 5 thyroid lobes (group 2). The ultrasound scans and the pre-and post-enhancement CT scans were undertaken before and immediately after the procedures, and at 24 hours, 72 hours and 1 week later. The US and CT findings of the ablated tissue and complications were evaluated. Blood sampling was done at the pre-procedure time and 1 week later for evaluating the functional status of the thyroid gland. Laryngoscopy was done at the pre-procedure and post-procedure times, and at 24 hours, 72 hours and 1 week later for the evaluation of any recurrent laryngeal nerve palsy. The echo pattern of the ablated thyroid gland at immediately after the radiofrequency ablation appeared as poorly marginated and hyperechoic. On the US obtained 24 hours after radiofrequency ablation, the echo pattern of the ablated thyroid gland was hypoechoic. The maximum diameters after RFA were 9.4 ρ 0.5 mm in group I and 11.4 ρ 0.5 mm in group II. The pre-enhanced CT scan taken at immediately after the radiofrequency ablation showed ill defined hypodense areas in the ablated thyroid gland. Differentiation between the normal and abnormal portions of the thyroid gland was difficult on the contrast enhanced CT scan. Complications induced by radiofrequency ablation were one recurrent laryngeal nerve palsy, two perforations of esophagus and five thickenings of the esophageal wall

Ultrasound-guided radiofrequency ablation of thyroid gland: a preliminary study in dogs

Energy Technology Data Exchange (ETDEWEB)

Choi, Ji Won; Yoo, Seung Min [College of Medicine, Chungang University, Seoul, (Korea, Republic of); Kwak, Seo Hyun [Seoul Veterans Hospital, Seoul (Korea, Republic of)

2005-07-15

The purpose of this study was to evaluate the possibility of using radiofrequency ablation as the treatment modality for the benign or malignant thyroid nodules in humans. Therefore, we examined the results of using radiofrequency ablation on the thyroid glands in dogs, in respect of the extent of the ablated tissue and the complications. Five dogs (10 lobes of the thyroid glands) were included in this study. US-guided radiofrequency ablation was undertaken with a 10 mm, uncovered 17 gauge cool-tip needle. The power and duration was 20 wattage and 1 minute in five thyroid lobes (group 1) and 20 wattage and 2 minutes in another 5 thyroid lobes (group 2). The ultrasound scans and the pre-and post-enhancement CT scans were undertaken before and immediately after the procedures, and at 24 hours, 72 hours and 1 week later. The US and CT findings of the ablated tissue and complications were evaluated. Blood sampling was done at the pre-procedure time and 1 week later for evaluating the functional status of the thyroid gland. Laryngoscopy was done at the pre-procedure and post-procedure times, and at 24 hours, 72 hours and 1 week later for the evaluation of any recurrent laryngeal nerve palsy. The echo pattern of the ablated thyroid gland at immediately after the radiofrequency ablation appeared as poorly marginated and hyperechoic. On the US obtained 24 hours after radiofrequency ablation, the echo pattern of the ablated thyroid gland was hypoechoic. The maximum diameters after RFA were 9.4 {rho} 0.5 mm in group I and 11.4 {rho} 0.5 mm in group II. The pre-enhanced CT scan taken at immediately after the radiofrequency ablation showed ill defined hypodense areas in the ablated thyroid gland. Differentiation between the normal and abnormal portions of the thyroid gland was difficult on the contrast enhanced CT scan. Complications induced by radiofrequency ablation were one recurrent laryngeal nerve palsy, two perforations of esophagus and five thickenings of the esophageal

Stepwise radiofrequency ablation of Barrett's esophagus preserves esophageal inner diameter, compliance, and motility

NARCIS (Netherlands)

Beaumont, H.; Gondrie, J. J.; McMahon, B. P.; Pouw, R. E.; Gregersen, H.; Bergman, J. J.; Boeckxstaens, G. E.

2009-01-01

Background and aim: Stepwise endoscopic circumferential and focal radiofrequency ablation is safe and effective for the eradication of Barrett's esophagus. In contrast to other techniques, radiofrequency ablation appears to avoid significant esophageal scarring or stenosis. Our aim was to evaluate

Superconducting Radio-Frequency Cavities

Science.gov (United States)

Padamsee, Hasan S.

2014-10-01

Superconducting cavities have been operating routinely in a variety of accelerators with a range of demanding applications. With the success of completed projects, niobium cavities have become an enabling technology, offering upgrade paths for existing facilities and pushing frontier accelerators for nuclear physics, high-energy physics, materials science, and the life sciences. With continued progress in basic understanding of radio-frequency superconductivity, the performance of cavities has steadily improved to approach theoretical capabilities.

Influence of radiofrequency surgery on architecture of the palatine tonsils.

Science.gov (United States)

Plzak, Jan; Macokova, Pavla; Zabrodsky, Michal; Kastner, Jan; Lastuvka, Petr; Astl, Jaromir

2014-01-01

Radiofrequency surgery is a widely used modern technique for submucosal volume reduction of the tonsils. So far there is very limited information on morphologic changes in the human tonsils after radiofrequency surgery. We performed histopathological study of tonsillectomy specimens after previous bipolar radiofrequency induced thermotherapy (RFITT). A total of 83 patients underwent bipolar RFITT for hypertrophy of palatine tonsils. Tonsil volume reduction was measured by 3D ultrasonography. Five patients subsequently underwent tonsillectomy. Profound histopathological examination was performed to determine the effect of RFITT on tonsillar architecture. All tonsillectomy specimens showed the intact epithelium, intact germinal centers, normal vascularization, and no evidence of increased fibrosis. No microscopic morphological changes in tonsillectomy specimens after bipolar RFITT were observed. RFITT is an effective submucosal volume reduction procedure for treatment of hypertrophic palatine tonsils with no destructive effect on microscopic tonsillar architecture and hence most probably no functional adverse effect.

Systematic Review of Radiofrequency Ablation and Pulsed Radiofrequency for Management of Cervicogenic Headaches.

Science.gov (United States)

Grandhi, Ravi K; Kaye, Alan David; Abd-Elsayed, Alaa

2018-02-23

Cervicogenic headache (CHA) is a secondary headache which has a source in the upper cervical spine. Many traditional analgesic choices lack good efficacy in managing the associated pain. As a result, in management of CHA, radiofrequency ablation (RFA) or pulse radiofrequency (PRF) has been tried with success. Our study investigated the use of RFA and PRF for the management of CHA. In the present investigation, a review of the literature was conducted using PubMed (1966 to February 2017). The quality assessment was determined using The Cochrane Risk of Bias. After initial search and consultation with experts, 34 articles were identified for initial review and 10 articles met inclusion for review. Criteria for inclusion were primarily based on identification of articles discussing cervicogenic headaches which were previously treatment resistant and occurred without any other pathology of the craniofacial region or inciting event such as trauma. This systematic review demonstrated that RFA and PRFA provide very limited benefit in the management of CHA. At present, there is no high-quality RCT and/or strong non-RCTs to support the use of these techniques, despite numerous case reports which have demonstrated benefit. This review is one of the first to provide a comprehensive overview of the use of RFA and PRF in the management of CHA.

Efficacy and safety of catheter-based radiofrequency renal denervation in stented renal arteries.

Science.gov (United States)

Mahfoud, Felix; Tunev, Stefan; Ruwart, Jennifer; Schulz-Jander, Daniel; Cremers, Bodo; Linz, Dominik; Zeller, Thomas; Bhatt, Deepak L; Rocha-Singh, Krishna; Böhm, Michael; Melder, Robert J

2014-12-01

In selected patients with hypertension, renal artery (RA) stenting is used to treat significant atherosclerotic stenoses. However, blood pressure often remains uncontrolled after the procedure. Although catheter-based renal denervation (RDN) can reduce blood pressure in certain patients with resistant hypertension, there are no data on the feasibility and safety of RDN in stented RA. We report marked blood pressure reduction after RDN in a patient with resistant hypertension who underwent previous stenting. Subsequently, radiofrequency ablation was investigated within the stented segment of porcine RA, distal to the stented segment, and in nonstented RA and compared with stent only and untreated controls. There were neither observations of thrombus nor gross or histological changes in the kidneys. After radiofrequency ablation of the nonstented RA, sympathetic nerves innervating the kidney were significantly reduced, as indicated by significant decreases in sympathetic terminal axons and reduction of norepinephrine in renal tissue. Similar denervation efficacy was found when RDN was performed distal to a renal stent. In contrast, when radiofrequency ablation was performed within the stented segment of the RA, significant sympathetic nerve ablation was not seen. Histological observation showed favorable healing in all arteries. Radiofrequency ablation of previously stented RA demonstrated that RDN provides equally safe experimental procedural outcomes in a porcine model whether the radiofrequency treatment is delivered within, adjacent, or without the stent struts being present in the RA. However, efficacious RDN is only achieved when radiofrequency ablation is delivered to the nonstented RA segment distal to the stent. © 2014 American Heart Association, Inc.

Pulse-Dose Radiofrequency in Athletic Pubalgia: Preliminary Results.

Science.gov (United States)

Masala, Salvatore; Fiori, Roberto; Raguso, Mario; Ojango, Christine; Morini, Marco; Cuzzolino, Alessandro; Calabria, Eros; Simonetti, Giovanni

2017-05-01

Chronic pubalgia affects around 10% of athletes. To determine the role of pulse-dose radiofrequency (PDRF) in athletes with chronic pubalgia and investigate the causes with imaging. Prospective nonrandomized single-group study. PDRF was performed on 32 patients with a chronic pain that had been refractory to conservative therapies during the last 3 mo. The genital branches of the genitofemoral, ilioinguinal, and iliohypogastric nerves and the obturator nerve were the goals of treatment. A 10-cm, 20-gauge cannula was inserted with a percutaneous access on the upper and lower edges of the iliopubic branch. After the spindle was removed, a radiofrequency needle with a 10-mm "active tip" was inserted. The radiofrequency technique was performed with 1200 pulses at 45 V and 20-ms duration, followed by a 480-ms silent phase. The follow-up with a clinical examination was performed at 1, 3, 6, and 9 mo after the procedure. During the follow-up visits, the patients were asked to rate their pain on a 0-10 VAS scale. All of the enrolled patients completed the study. Mean VAS score before the treatment was 8.4 ± 0.6. Twenty-four patients had a reduction of pain VAS scores more than 50% during all follow-up visits and started training and physiotherapy in the days after the radiofrequency procedure. Six patients, each treated 2 times, had a reduction more than 50% of VAS scores and could start training and physiotherapy only after the 2nd procedure. One patient had no pain relief with 2 treatments. Pain intensity decreased up to 9 mo in 31 patients (mean VAS scores 3.4 ± 0.5 at 6 mo and 3.8 ± 0.9 at 9 mo). No complications were observed. PDRF is an effective and safe technique in management of chronic pubalgia in athletes.

Gated blood-pool SPECT assessment of Wolff-Parkinson-White syndromes before and after radiofrequency ablation of accessory pathways; Evaluation fonctionnelle par tomographie cavitaire du syndrome de Wolff-Parkinson-White, avant et apres traitement par radiofrequence

Energy Technology Data Exchange (ETDEWEB)

Bontemps, L.; Ben Brahim, H.; Kraiem, T.; Chevalier, P.; Kirkorian, G.; Touboul, P.; Itti, R. [Hopital Cardiologique de Lyon, 69 (France)

1997-08-01

Radiofrequency (RF) ablation of accessory pathways in Wolff-Parkinson-White (WPW) syndrome is supposed to be less aggressive than fulguration while providing excellent results. The aims of our study were therefore the evaluation of the functional results of this therapy in terms of left or right ejection fractions and its effects on the contraction synchronism between both ventricular chambers, derived from bi-ventricular Fourier phase histograms. A consecutive series of 44 patients has been investigated within 48 hours before and after RF therapy: 14 patients had right sided WPW and 30 patients left sided WPW. Only patients for whom RF treatment was considered as a success have been included in the study. Gated blood pool tomography has been performed in order to localize the site of pre-excitation and to build-up the phase histograms for both ventricles, and planar gated imaging has been used for right and left ejection fraction determination. Functional results demonstrate the absence of deleterious effect of RF on ventricular contraction and rather a slight increase of ejection fractions, with a more statistically significant difference for left WPW (LVEF = 62.2 % before RF vs 64.4 % after RF; p = 0.02) than for right WPW (RVEF = 36.3 % before RF vs 39.7 after RF; p = 0.16). Phase analysis, on the contrary, show only significant differences for right WPW, with a noticeable decrease of the pre-excitation (left-to-right phase difference 14.4 deg before RF vs 7.5 deg after RF; p = 0.03) and a significant reduction of the right ventricular phase dispersion (right phase standard deviation 26.5 deg before RF vs 19.0 deg after RF; p = 0.03). For left WPW no measurable differences can be demonstrated in the basal state and it is suggested to use stimulation techniques in order to enhance the competition between the normal and accessory conduction pathways. (authors). 17 refs.

Perivascular radiofrequency renal denervation lowers blood pressure and ameliorates cardiorenal fibrosis in spontaneously hypertensive rats

Science.gov (United States)

Zhang, Yan; Su, Linan; Zhang, Yunrong; Wang, Qiang; Yang, Dachun; Li, De; Yang, Yongjian; Ma, Shuangtao

2017-01-01

Background Catheter-based renal denervation (RDN) is a promising approach to treat hypertension, but innervation patterns limit the response to endovascular RDN and the post-procedural renal artery narrowing or stenosis questions the endovascular ablation strategy. This study was performed to investigate the anti-hypertensive and target organ protective effects of perivascular RDN in spontaneously hypertensive rats (SHR). Methods SHR and normotensive Wistar-Kyoto (WKY) rats were divided into sham group (n = 10), radiofrequency ablation group (n = 20) in which rats received bilateral perivascular ablation with radiofrequency energy (2 watts), and chemical (10% phenol in 95% ethanol) ablation group (n = 12). The tail-cuff blood pressure was measured before the ablation and on day 14 and day 28 after the procedure. The plasma levels of creatinine, urea nitrogen, and catecholamines, urinary excretion of electrolytes and protein, and myocardial and glomerular fibrosis were analyzed and compared among the groups on day 28 after the procedure. Results We identified that 2-watt is the optimal radiofrequency power for perivascular RDN in rats. Perivascular radiofrequency and chemical ablation achieved roughly comparable blood pressure reduction in SHR but not in WKY on day 14 and day 28 following the procedure. Radiofrequency-mediated ablation substantially destroyed the renal nerves surrounding the renal arteries of both SHR and WKY without damaging the renal arteries and diminished the expression of tyrosine hydroxylase, the enzyme marker for postganglionic sympathetic nerves. Additionally, perivascular radiofrequency ablation also decreased the plasma catecholamines of SHR. Interestingly, both radiofrequency and chemical ablation decreased the myocardial and glomerular fibrosis of SHR, while neither increased the plasma creatinine and blood urea nitrogen nor affected the urinary excretion of electrolytes and protein when compared to sham group. Conclusions Radiofrequency

Radiofrequency glow discharge time of flight mass spectrometry: pulsed vs. continuous mode

International Nuclear Information System (INIS)

Lobo, L.; Pereiro, R.; Sanz-Medel, A.; Bordel, N.; Tempez, A.; Chapon, P.; Hohl, M.; Michler, J.

2009-01-01

Full text: Glow discharge (GD) is a well established tool for the direct analysis of solids. The application field of the original direct current GD, restricted to conductive samples, has been extended by radiofrequency powered GDs that can be applied for conductive and non-conductive samples. Moreover, the introduction of pulsed GD has opened the possibility of applying higher instantaneous powers that can improve the atomization-ionization processes and therefore the sensitivity. Furthermore, pulsed-GD may enable temporal separation of discharge gas species from the sample ions. In this work the analytical performances of radiofrequency and pulsed radiofrequency glow discharges are evaluated by using a time of flight mass analyzer (TOFMS). (author)

Radiofrequency fields in our surroundings

International Nuclear Information System (INIS)

2011-01-01

In 2010, the National Radiation Protection Authority (NRPA) with the Post and Telecommunications Authority carried out a project where it is measured radiofrequency fields from various telecom systems in homes, kindergartens, schools, offices, and urban environments. Close to 99 percent of the measurement points were found values of less than one thousandth of the maximum. No values were near the limits. (AG)

Atorvastatin can ameliorate left atrial stunning induced by radiofrequency ablation for atrial fibrillation.

Science.gov (United States)

Xie, Ruiqin; Yang, Yingtao; Cui, Wei; Yin, Hongning; Zheng, Hongmei; Zhang, Jidong; You, Ling

2017-09-01

The objective of this study was to study the functional changes of the left atrium after radiofrequency ablation treatment for atrial fibrillation and the therapeutic effect of atorvastatin. Fifty-eight patients undergoing radiofrequency ablation for atrial fibrillation were randomly divided into non-atorvastatin group and atorvastatin group. Patients in the atorvastatin group were treated with atorvastatin 20 mg p.o. per night in addition to the conventional treatment of atrial fibrillation; patients in the non-atorvastatin group received conventional treatment of atrial fibrillation only. Echocardiography was performed before radiofrequency ablation operation and 1 week, 2 weeks, 3 weeks, and 4 weeks after operation. Two-dimensional ultrasound speckle tracking imaging system was used to measure the structural indexes of the left atrium. Results indicated that there was no significant change for indexes representing the structural status of the left atrium within a month after radiofrequency ablation (P > 0.05); however, there were significant changes for indexes representing the functional status of the left atrium. There were also significant changes in indexes reflecting left atrial strain status: the S and SRs of atorvastatin group were higher than those of non-atorvastatin group (P atorvastatin could improve left atrial function and shorten the duration of atrial stunning after radiofrequency ablation of atrial fibrillation.

Effects of radiation from a radiofrequency identification (RFID) microchip on human cancer cells.

Science.gov (United States)

Lai, Henry C; Chan, Ho Wing; Singh, Narendra P

2016-01-01

Radiofrequency identification (RFID) microchips are used to remotely identify objects, e.g. an animal in which a chip is implanted. A passive RFID microchip absorbs energy from an external source and emits a radiofrequency identification signal which is then decoded by a detector. In the present study, we investigated the effect of the radiofrequency energy emitted by a RFID microchip on human cancer cells. Molt-4 leukemia, BT474 breast cancer, and HepG2 hepatic cancer cells were exposed in vitro to RFID microchip-emitted radiofrequency field for 1 h. Cells were counted before and after exposure. Effects of pretreatment with the spin-trap compound N-tert-butyl-alpha-phenylnitrone or the iron-chelator deferoxamine were also investigated. Results We found that the energy effectively killed/retarded the growth of the three different types of cancer cells, and the effect was blocked by the spin-trap compound or the iron-chelator, whereas an inactive microchip and energy from the external source had no significant effect on the cells. Conclusions Data of the present study suggest that radiofrequency field from the microchip affects cancer cells via the Fenton Reaction. Implantation of RFID microchips in tumors may provide a new method for cancer treatment.

Radio-frequency wave enhanced runaway production rate

International Nuclear Information System (INIS)

Chan, V.S.; McClain, F.W.

1983-01-01

Enhancement of runaway electron production (over that of an Ohmic discharge) can be achieved by the addition of radio-frequency waves. This effect is studied analytically and numerically using a two-dimensional Fokker--Planck quasilinear equation

First muon acceleration using a radio-frequency accelerator

Directory of Open Access Journals (Sweden)

S. Bae

2018-05-01

Full Text Available Muons have been accelerated by using a radio-frequency accelerator for the first time. Negative muonium atoms (Mu^{-}, which are bound states of positive muons (μ^{+} and two electrons, are generated from μ^{+}’s through the electron capture process in an aluminum degrader. The generated Mu^{-}’s are initially electrostatically accelerated and injected into a radio-frequency quadrupole linac (RFQ. In the RFQ, the Mu^{-}’s are accelerated to 89 keV. The accelerated Mu^{-}’s are identified by momentum measurement and time of flight. This compact muon linac opens the door to various muon accelerator applications including particle physics measurements and the construction of a transmission muon microscope.

Protease-activated receptor (PAR)-2 is required for PAR-1 signalling in pulmonary fibrosis

NARCIS (Netherlands)

Lin, Cong; von der Thüsen, Jan; Daalhuisen, Joost; ten Brink, Marieke; Crestani, Bruno; van der Poll, Tom; Borensztajn, Keren; Spek, C. Arnold

2015-01-01

Idiopathic pulmonary fibrosis is the most devastating diffuse fibrosing lung disease of unknown aetiology. Compelling evidence suggests that both protease-activated receptor (PAR)-1 and PAR-2 participate in the development of pulmonary fibrosis. Previous studies have shown that bleomycin-induced

Non-invasive ultrasound-based temperature imaging for monitoring radiofrequency heating-phantom results

International Nuclear Information System (INIS)

Daniels, M J; Varghese, T; Madsen, E L; Zagzebski, J A

2007-01-01

Minimally invasive therapies (such as radiofrequency ablation) are becoming more commonly used in the United States for the treatment of hepatocellular carcinomas and liver metastases. Unfortunately, these procedures suffer from high recurrence rates of hepatocellular carcinoma (∼34-55%) or metastases following ablation therapy. The ability to perform real-time temperature imaging while a patient is undergoing radiofrequency ablation could provide a significant reduction in these recurrence rates. In this paper, we demonstrate the feasibility of ultrasound-based temperature imaging on a tissue-mimicking phantom undergoing radiofrequency heating. Ultrasound echo signals undergo time shifts with increasing temperature, which are tracked using 2D correlation-based speckle tracking methods. Time shifts or displacements in the echo signal are accumulated, and the gradient of these time shifts are related to changes in the temperature of the tissue-mimicking phantom material using a calibration curve generated from experimental data. A tissue-mimicking phantom was developed that can undergo repeated radiofrequency heating procedures. Both sound speed and thermal expansion changes of the tissue-mimicking material were measured experimentally and utilized to generate the calibration curve relating temperature to the displacement gradient. Temperature maps were obtained, and specific regions-of-interest on the temperature maps were compared to invasive temperatures obtained using fiber-optic temperature probes at the same location. Temperature elevation during a radiofrequency ablation procedure on the phantom was successfully tracked to within ±0.5 0 C

International radiofrequency standards

International Nuclear Information System (INIS)

Lincoln, J.

2001-01-01

Of the various radiofrequency standards in use around the world, many are based on or similar to the Guidelines published by ICNIRP (The International Commission on Non-ionising Radiation Protection). This organisation is a working group operating in co-operation with the Environmental Health division of the World Health Organisation (WHO). This paper presents a very brief overview of current international standards, beginning with a summary of the salient points of the ICNIRP Guidelines. It should be remembered that these are guidelines only and do not exist as a separate standard. Copyright (2001) Australasian Radiation Protection Society Inc

Management of trigeminal neuralgia by radiofrequency ...

African Journals Online (AJOL)

The outcome depends on the type of TN with best results with classical idiopathic type. Also better results occurred with isolated V3 affection. The radiofrequency thermocoagulation of trigeminal nerve is a low risk, highly effective and minimally invasive procedure that should be started with in all cases of TN.

INTRAOPERATIVE RADIOFREQUENCY AND CRYOABLATION FOR ATRIAL FIBRILLATION IN PATIENTS WITH VALVULAR HEART DISEASE

Directory of Open Access Journals (Sweden)

N. Maghamipour N. Safaie

2007-05-01

Full Text Available Patients with valvular heart disease and suffering atrial fibrillation of more than 12 months duration have a low probability of remaining in sinus rhythm after valve surgery alone. We performed intra-operative radiofrequency ablation or cryoablation as an alternative to surgical maze ІІІ procedure to create linear lesion lines for conversion of this arrhythmia to sinus rhythm. A total of 30 patients with valvular heart disease and chronic persistent atrial fibrillation underwent different combinations of valve surgery and concomitant maze procedure with radiofrequency or cryo probes. These patients aged 48.10 ± 9.84 years in radiofrequency ablation group and 51.10 ± 13.93 years in cryoablation group. Both atrial ablation with radiofrequency probes, needed 26.15 ± 3.67 min extra ischemic time and ablation by mean of cryo-probes needed an extra ischemic time of 29.62 ± 4.27 min. There was one in hospital death postoperatively because of respiratory failure but no other complication. 6 months after the operation, among 30 patients with both atrial ablations, 25 patients were in sinus rhythm, no patient had junctional rhythm and 5 patients had persistent atrial fibrillation. At 12 months follow up, freedom from atrial fibrillation was 85% in radiofrequency group and 80% in cryo group. Doppler echocardiography in these patients demonstrated atrial contractility in 70% of the patients. Intraoperative radiofrequency or cryo-ablation of both atriums are effective and less invasive alternatives for the original maze procedure to eliminate the atrial fibrillation, and can be done in patients with valvular heart disease without increasing the risk of operation.

Intraarticular Pulsed Radiofrequency to Treat Refractory Lumbar Facet Joint Pain in Patients with Low Back Pain.

Science.gov (United States)

Chang, Min Cheol; Cho, Yun-Woo; Ahn, Da Hyun; Do, Kyung Hee

2018-04-01

Many treatment techniques have been used for refractory lumbar facet joint pain; however, their efficacy has been controversial. In this study, we investigated the clinical efficacy and safety of intra-articular pulsed radiofrequency for the treatment of refractory lumbar facet joint pain in patients with low back pain. Twenty patients with refractory lumbar facet joint pain were recruited, and each patient was treated via intra-articular pulsed radiofrequency. The treatment effects were measured with a numerical rating scale, and the technical accuracy of intra-articular pulsed radiofrequency treatment was evaluated independently by 2 radiologists. Any adverse events or complications also were checked. We performed intra-articular pulsed radiofrequency treatment at 48 levels of the lumbar facet joints in 20 patients (5 men and 15 women; mean age, 64.50 ± 10.65 years) with refractory lumbar facet joint pain. Pain scores were significantly reduced at 1 month, 3 months, and 6 months after treatment (P radiofrequency results in all 20 patients, without any serious adverse effects. Treatment using intra-articular pulsed radiofrequency is an alternative to other techniques in patients with refractory lumbar facet joint pain. Copyright © 2018 Elsevier Inc. All rights reserved.

Ion-storage in radiofrequency electric quadrupole field

International Nuclear Information System (INIS)

Gheorghe, V.

1976-01-01

The confinement of charged particles in a quadrupole radiofrequency electric field are presented. The stability diagrams and phase space trajectories for the quadrupole mass spectrometer and for the ion trap are represented and their main characteristics are discussed. (author)

Massive hematemesis after radiofrequency ablation of metastatic liver tumor with successful hemostasis achieved through transarterial embolization.

Science.gov (United States)

Liu, Chien-An; Chiu, Nai-Chi; Chiou, Yi-You

2018-03-03

Hemorrhagic complications are the most common major complications that occur after radiofrequency ablation, but hematemesis as a complication after radiofrequency ablation for hepatic tumor has not been mentioned before. A hepatogastric fistula as a delayed complication is also rare. We present the case of a 77-year-old man with severe hematemesis that occurred 2 months after radiofrequency ablation of a liver metastasis of gastric cancer. A ruptured hepatic artery pseudoaneurysm and a hepatogastric fistula were confirmed through serial imaging examinations. The current case is reported in combination with 2 rare major complications after radiofrequency ablation of a liver tumor. Copyright © 2018. Published by Elsevier Inc.

21 CFR 880.6300 - Implantable radiofrequency transponder system for patient identification and health information.

Science.gov (United States)

2010-04-01

... patient identification and health information. 880.6300 Section 880.6300 Food and Drugs FOOD AND DRUG... radiofrequency transponder system for patient identification and health information. (a) Identification. An implantable radiofrequency transponder system for patient identification and health information is a device...

Radio-frequency energy in fusion power generation

International Nuclear Information System (INIS)

Lawson, J.Q.; Becraft, W.R.; Hoffman, D.J.

1983-01-01

The history of radio-frequency (rf) energy in fusion experiments is reviewed, and the status of current efforts is described. Potential applications to tasks other than plasma heating are described, as are the research and development needs of rf energy technology

Modes of oscillation in radiofrequency Paul traps

DEFF Research Database (Denmark)

Landa, H.; Reznik, B.; Drewsen, M.

2012-01-01

We examine the time-dependent dynamics of ion crystals in radiofrequency traps. The problem of stable trapping of general threedimensional crystals is considered and the validity of the pseudopotential approximation is discussed. We analytically derive the micromotion amplitude of the ions...

Pulsed Dose Radiofrequency Before Ablation of Medial Branch of the Lumbar Dorsal Ramus for Zygapophyseal Joint Pain Reduces Post-procedural Pain.

Science.gov (United States)

Arsanious, David; Gage, Emmanuel; Koning, Jonathon; Sarhan, Mazin; Chaiban, Gassan; Almualim, Mohammed; Atallah, Joseph

2016-01-01

One of the potential side effects with radiofrequency ablation (RFA) includes painful cutaneous dysesthesias and increased pain due to neuritis or neurogenic inflammation. This pain may require the prescription of opioids or non-opioid analgesics to control post-procedural pain and discomfort. The goal of this study is to compare post-procedural pain scores and post-procedural oral analgesic use in patients receiving continuous thermal radiofrequency ablation versus patients receiving pulsed dose radiofrequency immediately followed by continuous thermal radiofrequency ablation for zygopophaseal joint disease. This is a prospective, double-blinded, randomized, controlled trial. Patients who met all the inclusion criteria and were not subject to any of the exclusion criteria were required to have two positive diagnostic medial branch blocks prior to undergoing randomization, intervention, and analysis. University hospital. Eligible patients were randomized in a 1:1 ratio to either receive thermal radiofrequency ablation alone (standard group) or pulsed dose radiofrequency (PDRF) immediately followed by thermal radiofrequency ablation (investigational group), all of which were performed by a single Board Certified Pain Medicine physician. Post-procedural pain levels between the two groups were assessed using the numerical pain Scale (NPS), and patients were contacted by phone on post-procedural days 1 and 2 in the morning and afternoon regarding the amount of oral analgesic medications used in the first 48 hours following the procedure. Patients who received pulsed dose radiofrequency followed by continuous radiofrequency neurotomy reported statistically significantly lower post-procedural pain scores in the first 24 hours compared to patients who received thermal radiofrequency neurotomy alone. These patients also used less oral analgesic medication in the post-procedural period. These interventions were carried out by one board accredited pain physician at one

Thermal Protection with 5% Dextrose Solution Blanket During Radiofrequency Ablation

International Nuclear Information System (INIS)

Chen, Enn Alexandria; Neeman, Ziv; Lee, Fred T.; Kam, Anthony; Wood, Brad

2006-01-01

A serious complication for any thermal radiofrequency ablation is thermal injury to adjacent structures, particularly the bowel, which can result in additional major surgery or death. Several methods using air, gas, fluid, or thermometry to protect adjacent structures from thermal injury have been reported. In the cases presented in this report, 5% dextrose water (D5W) was instilled to prevent injury to the bowel and diaphragm during radiofrequency ablation. Creating an Insulating envelope or moving organs with D5W might reduce risk for complications such as bowel perforation

Exposure of Ontario workers to radiofrequency fields from dielectric heaters

International Nuclear Information System (INIS)

Bitran, M.E.; Nishio, J.M.; Charron, D.E.

1992-01-01

As part of a program to assess and reduce the exposure of Ontario workers to non-ionizing radiations, stray electric and magnetic fields from 383 dielectric heaters were measured in 71 industrial establishments from 1988 to 1990. This represents a population of over 800 workers potentially exposed to radiofrequency (RE) electromagnetic fields. Electric and magnetic field strengths at the head, waist, and thigh levels of the operators, corrected by duty cycle, are presented for the different heater types surveyed. Worker exposure data and compliance with Ontario radiofrequency exposure guidelines are discussed. (author)

Radiofrequency Denervation Improves Health-Related Quality of Life in Patients with Thoracic Zygapophyseal Joint Pain.

Science.gov (United States)

Hambraeus, Johan; Hambraeus, Kjerstin S; Persson, Jan

2018-05-01

To describe a practical approach for the diagnosis and treatment of thoracic zygapophyseal joint pain and to present preliminary clinical data on the effects of this treatment approach on health-related quality of life. An observational study. Specialist outpatient pain clinic in northern Sweden. Patients with long-term thoracic pain. We describe a method of radiofrequency denervation of thoracic zygapophyseal joints. We compared health-related quality of life between patients who underwent radiofrequency denervation of thoracic zygapophyseal joints and patients who underwent radiofrequency denervation for lumbar and cervical zygapophyseal joint pain. Treatment according to the Spine Intervention Society Guidelines was performed on the lumbar region in 178 patients and in the cervical region in 55 patients. Another 82 patients were treated in the thoracic region with our proposed technique. A survival plot of improvements in health-related quality of life revealed that all three treatments were effective in 65% or more of patients. The improvement in health-related quality of life was maintained for 12 or more months after treatment in 47% to 51% of patients. Our results suggest that radiofrequency denervation of thoracic zygapophyseal joint pain is as effective as radiofrequency denervation, the standard treatment, for lumbar and cervical zygapophyseal joint pain. If these results can be confirmed by other centers, radiofrequency denervation is likely to become more widely available for the treatment of thoracic zygapophyseal joint pain.

Radiofrequency/infrared double resonance spectroscopy of the HD+ ion

International Nuclear Information System (INIS)

Carrington, Alan; McNab, I.R.; Montgomerie, C.A.

1989-01-01

We describe a double resonance technique for obtaining radiofrequency spectra of the HD + ion in vibration-rotation levels close to the dissociation limit. Infrared transitions are driven by Doppler tuning an HD + ion beam into resonance with a carbon dioxide infrared laser, and are detected by measuring H + fragment ions produced by electric field dissociation of the upper vibration-rotation level. Radiofrequency transitions between nuclear hyperfine components of the lower vibration-rotation level are then detected through resonant increases in the H + fragment ion current. The high spectroscopic resolution obtained, and the ability to measure magnetic dipole hyperfine transitions, will enable the hyperfine constants to be determined accurately. (author)

Effect of Mobile Phone Radiofrequency Electromagnetic Fields on ...

African Journals Online (AJOL)

olayemitoyin

Summary: Since cell phones emit radiofrequency electromagnetic fields (EMFs), this study tested the hypothesis that cell phones placed ... mobile phones on autonomic modulation of the heart. ..... Electrocardiogram and Its Technology. J. Am.

[Percutaneous radiofrequency ablation of hepatic metastases. Preliminary experience].

Science.gov (United States)

De Baere, T; Elias, D; Ducreux, M; Dromain, C; Kuach, V; Gamal El Din, M; Sobotka, A; Lasser, P; Roche, A

1999-11-01

To evaluate the efficiency of percutaneous radiofrequency ablation in the treatment of liver metastases. Eighteen patients with 31 liver metastases, mainly from colorectal cancer, 10 - 35 mm in diameter (m = 23), underwent 26 courses of percutaneous radiofrequency ablation. Fifteen patients had previously undergone hepatectomy, and 3 patients had contra-indications to surgery. Imaging guidance was ultrasound in 21 patients, CT in 4 (tumors not seen with ultrasound), and both in 1. A generator working at 450 KHz with a maximum output power of 150 W was used to treat each lesion for 18 - 20 min. Treatment was monitored with real time ultrasound. Among the 12 patients followed more than 3 months, only one of the 24 treated lesions recurred after a mean follow up of 259 ¿ 109 days. Liver disease was controlled in 8 of the 12 patients after 90 - 509 days (m = 306). Among these 8 patients, 3 were tumor free after 559, 378 and 90 days, respectively; 2 died tumor free of non-tumoral disease (pulmonary embolism, digestive bleeding); 3 developed lung metastases treated with chemotherapy (n = 2) or surgery (n = 1). Three of the 12 patients had widespread hepatic tumor occurrence, and one patient died of these metastases. Six patients experienced mild skin burns, but no major complication was observed. Radiofrequency ablation of hepatic metastases appears safe and promising in this preliminary experience. Further investigation is needed.

Radiofrequency Coblation Versus Intramural Bipolar Cautery for the Treatment of Inferior Turbinate Hypertrophy.

Science.gov (United States)

Shah, Anil N; Brewster, Douglas; Mitzen, Kelly; Mullin, David

2015-09-01

Compare intramural bipolar electrocautery and radiofrequency coblation in the treatment of inferior turbinate hypertrophy with regards to objective and subjective improvement in nasal obstruction, rate and type of complications, experience during the procedure, and rate of recovery. Prospective, single-blinded study. Single tertiary medical center from 2008 to 2010. Forty-one adult patients with inferior turbinate hypertrophy refractory to medical management were treated with radiofrequency coblation in one nostril and intramural bipolar cautery in the other. Subjective and objective data, including use of a Visual Analog Scale (VAS) for subjective outcomes, acoustic rhinometry, and nasal endoscopy, were then obtained from each patient comparing the 2 techniques. Radiofrequency coblation was significantly less painful than intramural bipolar cautery during the procedure (P = .03) and during the early postoperative period (P measured by acoustic rhinometry and subjective VAS outcomes. Radiofrequency coblation seems to offer an equivalent alternative to bipolar electrocautery for the treatment of inferior turbinate hypertrophy with less discomfort during the procedure and early post-operative period. © The Author(s) 2015.

Single strip lesions radiofrequency denervation for treatment of sacroiliac joint pain: two years' results.

Science.gov (United States)

Bellini, Martina; Barbieri, Massimo

2016-01-01

Sacroiliac joint pain can be managed by intra-articular injections or radiofrequency of its innervation. Single strip lesions radiofrequency denervation is a new system. The objective of this study was to present one of the first utilizations of this innovative technique. 60 patients who met the diagnostic criteria for sacroiliac joint syndrome were enrolled in the study. In total, 102 single strip lesions radiofrequency denervations were performed. Pain intensity was measured with the Oswestry low back pain disability questionnaire and the Oswestry Disability Index whose scores were assessed at 1, 3, 6 and 12 months after the procedure. 91.8 % of the 102 radiofrequency treatments resulted in a reduction of more than 50% pain intensity relief at 1 month, 81.6% at 3 months and 59.16% at 6 months. In 35.7% of cases, the relief was continuative up to 1 year. No relief was observed in 12.24% of cases. The ODI scores improved significantly 1 month after the procedure, compared with the baseline scores. The ODI scores after 6 months improved very clearly compared with the baseline scores and with the 3-month scores. Single strip lesions radiofrequency denervation using the Simplicity III probe is a potential modality for intermediate term relief for patients with sacroiliac pain.

Pulmonary venous thrombosis secondary to radiofrequency ablation of the pulmonary veins

Directory of Open Access Journals (Sweden)

Raquel López-Reyes

Full Text Available Background: Pulmonary Vein Thrombosis (PVT is a rare and underdiagnosed entity produced by local mechanical nature mechanisms, vascular torsion or direct injury to the vein. PVT has been described in clinical cases or small multicenter series mainly in relation to pulmonary vein stenosis, metastatic carcinoma, fibrosing mediastinitis, as an early surgical complication of lung transplantation lobectomy and radiofrequency ablation performed in patients with atrial fibrillation, although in some cases the cause is not known. Case: We report the case of a 57 years old male with history of atrial fibrillation treated by radiofrequency ablation who was admitted in our center because of a two-week history of consistent pleuritic pain in the left hemithorax and low-grade hemoptysis and a lung consolidation treated as a pneumonia with antibiotic but not responding to medical therapy. In view of the poor evolution of the patient, computed tomography angiography was performed with findings of PVT and secondary venous infarction and anticoagulation therapy was optimized. At the end, pulmonary resection was performed due to hemorrhagic recurrence. Conclusion: PVT remains a rare complication of radiofrequency ablation and other procedures involving pulmonary veins. Clinical suspicion and early diagnosis is crucial because is a potentially life-threatening entity. Keywords: Venous thrombosis, Atrial fibrilation, Radiofrequency ablation, Hemoptysis, Lung consolidation, Lung infarction, Lung resection surgery

Lesion size in relation to ablation site during radiofrequency ablation

DEFF Research Database (Denmark)

Petersen, H H; Chen, X; Pietersen, A

1998-01-01

This study was designed to investigate the effect of the convective cooling of the tip of the ablation electrode during temperature controlled radiofrequency ablation. In vivo two different application sites in the left ventricle of anaesthetised pigs were ablated and in vitro ablation was perfor......This study was designed to investigate the effect of the convective cooling of the tip of the ablation electrode during temperature controlled radiofrequency ablation. In vivo two different application sites in the left ventricle of anaesthetised pigs were ablated and in vitro ablation...... was performed during two different flow-velocities in a tissue bath, while electrode contact pressure and position were unchanged. Target temperature was 80 degrees C. Obtained tip temperature, power consumption and lesion dimensions were measured. In vivo lesion volume, depth and width were found significantly.......61 in vitro). We conclude that during temperature controlled radiofrequency ablation lesion size differs for septal and apical left ventricular applications. Differences in convective cooling might play an important role in this respect. This is supported by our in vitro experiments, where increased...

Radiofrequency and microwave interactions between biomolecular systems

Czech Academy of Sciences Publication Activity Database

Kučera, Ondřej; Cifra, Michal

2016-01-01

Roč. 42, č. 1 (2016), s. 1-8 ISSN 0092-0606 R&D Projects: GA ČR(CZ) GA15-17102S Institutional support: RVO:67985882 Keywords : Cell signaling * Radiofrequency * Bioelectrodynamics Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.241, year: 2016

Par Pond vegetation status Summer 1995 -- Summary

International Nuclear Information System (INIS)

Mackey, H.E. Jr.; Riley, R.S.

1996-01-01

The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the newly emergent, shoreline aquatic plant communities of Par Pond began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level. These surveys continued in July, September, and late October, 1995. Communities similar to the pre-drawdown, Par Pond aquatic plant communities are becoming re-established. Emergent beds of maidencane, lotus, waterlily, and watershield are extensive and well developed. Cattail occurrence continued to increase during the summer, but large beds common to Par Pond prior to the drawdown have not formed. Estimates from SPOT HRV, remote sensing satellite data indicated that as much as 120 hectares of emergent wetlands vegetation may have been present along the Par Pond shoreline by early October, 1995. To track the continued development of macrophytes in Par Pond, future surveys throughout 1996 and 1997, along with the continued evaluation of satellite data to map the areal extent of the macrophyte beds of Par Pond, are planned

The Biological Effects of Quadripolar Radiofrequency Sequential Application: A Human Experimental Study

OpenAIRE

Nicoletti, Giovanni; Cornaglia, Antonia Icaro; Faga, Angela; Scevola, Silvia

2014-01-01

Objective: An experimental study was conducted to assess the effectiveness and safety of an innovative quadripolar variable electrode configuration radiofrequency device with objective measurements in an ex vivo and in vivo human experimental model. Background data: Nonablative radiofrequency applications are well-established anti-ageing procedures for cosmetic skin tightening. Methods: The study was performed in two steps: ex vivo and in vivo assessments. In the ex vivo assessments the radio...

Temperature-Controlled Delivery of Radiofrequency Energy in Fecal Incontinence: A Randomized Sham-Controlled Clinical Trial.

Science.gov (United States)

Visscher, Arjan P; Lam, Tze J; Meurs-Szojda, Maria M; Felt-Bersma, Richelle J F

2017-08-01

Controlled delivery of radiofrequency energy has been suggested as treatment for fecal incontinence. The aim of this study was to determine whether the clinical response to the radiofrequency energy procedure is superior to sham in patients with fecal incontinence. This was a randomized sham-controlled clinical trial from 2008 to 2015. This study was conducted in an outpatient clinic. Forty patients with fecal incontinence in whom maximal conservative management had failed were randomly assigned to receiving either radiofrequency energy or sham procedure. Fecal incontinence was measured using the Vaizey incontinence score (range, 0-24). The impact of fecal incontinence on quality of life was measured by using the fecal incontinence quality-of-life score (range, 1-4). Measurements were performed at baseline and at 6 months. Anorectal function was evaluated using anal manometry and anorectal endosonography at baseline and at 3 months. At baseline, Vaizey incontinence score was 16.8 (SD 2.9). At t = 6 months, the radiofrequency energy group improved by 2.5 points on the Vaizey incontinence score compared with the sham group (13.2 (SD 3.1), 15.6 (SD 3.3), p = 0.02). The fecal incontinence quality-of-life score at t = 6 months was not statistically different. Anorectal function did not show any alteration. Patients with severe fecal incontinence were included in the study, thus making it difficult to generalize the results. Both radiofrequency energy and sham procedure improved the fecal incontinence score, the radiofrequency energy procedure more than sham. Although statistically significant, the clinical impact for most of the patients was negligible. Therefore, the radiofrequency energy procedure should not be recommended for patients with fecal incontinence until patient-related factors associated with treatment success are known. See Video Abstract at http://links.lww.com/DCR/A373.

Longitudinal outcomes of radiofrequency ablation versus surveillance endoscopy for Barrett's esophagus with low-grade dysplasia.

Science.gov (United States)

Kahn, A; Al-Qaisi, M; Kommineni, V T; Callaway, J K; Boroff, E S; Burdick, G E; Lam-Himlin, D M; Temkit, M; Vela, M F; Ramirez, F C

2018-04-01

Radiofrequency ablation of Barrett's esophagus with low-grade dysplasia is recommended in recent American College of Gastroenterology guidelines, with endoscopic surveillance considered a reasonable alternative. Few studies have directly compared outcomes of radiofrequency ablation to surveillance and those that have are limited by short duration of follow-up. This study aims to compare the long-term effectiveness of radiofrequency ablation versus endoscopic surveillance in a large, longitudinal cohort of patients with Barrett's esophagus, and low-grade dysplasia.We conducted a retrospective analysis of patients with confirmed low-grade dysplasia at a single academic medical center from 1991 to 2014. Patients progressing to high-grade dysplasia or esophageal adenocarcinoma within one year of index LGD endoscopy were defined as missed dysplasia and excluded. Risk factors for progression were assessed via Cox proportional hazards model. Comparison of progression risk was conducted using a Kaplan-Meier analysis. Subset analyses were conducted to examine the effect of reintroducing early progressors and excluding patients diagnosed prior to the advent of ablative therapy. Of 173 total patients, 79 (45.7%) underwent radiofrequency ablation while 94 (54.3%) were untreated, with median follow up of 90 months. Seven (8.9%) patients progressed to high-grade dysplasia or adenocarcinoma despite ablation, compared with 14 (14.9%) undergoing surveillance (P = 0.44). This effect was preserved when patients diagnosed prior to the introduction of radiofrequency ablation were excluded (8.9% vs 13%, P = 0.68). Reintroduction of patients progressing within the first year of follow-up resulted in a trend toward significance for ablation versus surveillance (11.1% vs 23.8%, P = 0.053).In conclusion, progression to high-grade dysplasia or adenocarcinoma was not significantly reduced in the radiofrequency ablation cohort when compared to surveillance. Despite recent studies

ParABS system in chromosome partitioning in the bacterium Myxococcus xanthus.

Directory of Open Access Journals (Sweden)

Antonio A Iniesta

Full Text Available Chromosome segregation is an essential cellular function in eukaryotic and prokaryotic cells. The ParABS system is a fundamental player for a mitosis-like process in chromosome partitioning in many bacterial species. This work shows that the social bacterium Myxococcus xanthus also uses the ParABS system for chromosome segregation. Its large prokaryotic genome of 9.1 Mb contains 22 parS sequences near the origin of replication, and it is shown here that M. xanthus ParB binds preferentially to a consensus parS sequence in vitro. ParB and ParA are essential for cell viability in M. xanthus as in Caulobacter crescentus, but unlike in many other bacteria. Absence of ParB results in anucleate cells, chromosome segregation defects and loss of viability. Analysis of ParA subcellular localization shows that it clusters at the poles in all cells, and in some, in the DNA-free cell division plane between two chromosomal DNA masses. This ParA localization pattern depends on ParB but not on FtsZ. ParB inhibits the nonspecific interaction of ParA with DNA, and ParA colocalizes with chromosomal DNA only when ParB is depleted. The subcellular localization of ParB suggests a single ParB-parS complex localized at the edge of the nucleoid, next to a polar ParA cluster, with a second ParB-parS complex migrating after the replication of parS takes place to the opposite nucleoid edge, next to the other polar ParA cluster.

Radiofrequency Ablation in Coccydynia: A Case Series and Comprehensive, Evidence-Based Review.

Science.gov (United States)

Chen, Yian; Huang-Lionnet, Julie H Y; Cohen, Steven P

2017-06-01

Coccydynia is a condition with a multitude of different causes, characterized by ill-defined management. There are multiple prospective studies, including several controlled trials, that have evaluated conservative therapies. Additionally, a plethora of observational studies have assessed coccygectomy, but few studies have reported results for nonsurgical interventional procedures. In this report, we describe the treatment results of 12 patients who received conventional or pulsed radiofrequency for coccydynia and systematically review the literature on management. We performed a retrospective data analysis evaluating patients who underwent pulsed or conventional radiofrequency treatment at Johns Hopkins Hospital and Walter Reed National Military Medical Center. A comprehensive literature review was also performed to contextualize these results. The mean age of patients treated was 50.25 years (SD = 11.20 years, range = 32-72 years), with the mean duration of symptoms being 3.6 years (SD = 3.36 years, range 1-10 years). There were 10 males and two females in this cohort. Among patients who received radiofrequency treatment, the average benefit was 55.5% pain relief (SD = 30.33%, range = 0-100%). Those who underwent conventional (vs pulsed radiofrequency) and who received prognostic blocks were more likely to experience a positive outcome. There were two cases of neuritis, which resolved spontaneously after several weeks. Radiofrequency ablation of the sacrococcygeal nerves may serve as a useful treatment option for patients with coccydynia who have failed more conservative measures. Further research into this therapeutic approach and its benefit for coccydynia should incorporate a control group for comparison. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Pulsed radiofrequency on radial nerve under ultrasound guidance for treatment of intractable lateral epicondylitis.

Science.gov (United States)

Oh, Dae Seok; Kang, Tae Hyung; Kim, Hyae Jin

2016-06-01

Lateral epicondylitis is a painful and functionally limiting disorder. Although lateral elbow pain is generally self-limiting, in a minority of people symptoms persist for a long time. When various conservative treatments fail, surgical approach is recommended. Surgical denervation of several nerves that innervate the lateral humeral epicondyle could be considered in patients with refractory pain because it denervates the region of pain. Pulsed radiofrequency is a minimally invasive procedure that improves chronic pain when applied to various neural tissues without causing any significant destruction and painful complication. This procedure is safe, minimally invasive, and has less risk of complications relatively compared to the surgical approach. The radial nerve can be identified as a target for pulsed radiofrequency lesioning in lateral epicondylitis. This innovative method of pulsed radiofrequency applied to the radial nerve has not been reported before. We reported on two patients with intractable lateral epicondylitis suffering from elbow pain who did not respond to nonoperative treatments, but in whom the ultrasound-guided pulsed radiofrequency neuromodulation of the radial nerve induced symptom improvement. After a successful diagnostic nerve block, radiofrequency probe adjustment around the radial nerve was performed on the lateral aspect of the distal upper arm under ultrasound guidance and multiple pulsed treatments were applied. A significant reduction in pain was reported over the follow-up period of 12 weeks.

TU-H-BRA-01: The Physics of High Power Radiofrequency Isolation in a Novel Compact Linear Accelerator Based MRI Guided Radiation Therapy System

Energy Technology Data Exchange (ETDEWEB)

Lamb, J; Low, D [University of California, Los Angeles, Los Angeles, CA (United States); Mutic, S [Washington University School of Medicine, Saint Louis, MO (United States); Shvartsman, S; Chmielewski, T; Fought, G; Sharma, A; Dempsey, J [ViewRay, Inc., Oakwood Village, OH (United States)

2016-06-15

Purpose: To develop a method for isolating the radiofrequency waves emanating from linear accelerator components from the magnetic resonance imaging (MRI) system of an integrated MRI-linac. Methods: An MRI-guided radiation therapy system has been designed that integrates a linear accelerator with simultaneous MR imaging. The radiofrequency waves created by the accelerating process would degrade MR image quality, so a method for containing the radiofrequency waves and isolating the MR imager from them was developed. The linear accelerator radiofrequency modulator was placed outside the room, so a filter was designed to eliminate the radiofrequency corresponding to the proton Larmour frequency of 14.7 MHz. Placing the radiofrequency emitting components in a typical Faraday cage would have reduced the radiofrequency emissions, but the design would be susceptible to small gaps in the shield due to the efficiency of the Faraday cage reflecting internal radiofrequency emissions. To reduce internal radiofrequency reflections, the Faraday cage was lined with carbon fiber sheets. Carbon fiber has the property of attenuating the radiofrequency energy so that the overall radiofrequency field inside the Faraday cage is reduced, decreasing any radiofrequency energy emitted from small gaps in the cage walls. Results: Within a 1.2 MHz band centered on the Larmor frequency, the radiofrequency (RF) leakage from the Faraday cage was measured to be −90 dB with no RF on, −40 dB with the RF on and no shield, returning to −90 dB with the RF on and shields in place. The radiofrequency filter attenuated the linear accelerator modulator emissions in the 14.7 MHz band by 70 dB. Conclusions: One of the major challenges in designing a compact linear accelerator based MRI-guided radiation therapy system, that of isolating the high power RF system from the MRI, has been solved. The measured radiofrequency emissions are sufficiently small to enable system integration. This research was

TU-H-BRA-01: The Physics of High Power Radiofrequency Isolation in a Novel Compact Linear Accelerator Based MRI Guided Radiation Therapy System

International Nuclear Information System (INIS)

Lamb, J; Low, D; Mutic, S; Shvartsman, S; Chmielewski, T; Fought, G; Sharma, A; Dempsey, J

2016-01-01

Purpose: To develop a method for isolating the radiofrequency waves emanating from linear accelerator components from the magnetic resonance imaging (MRI) system of an integrated MRI-linac. Methods: An MRI-guided radiation therapy system has been designed that integrates a linear accelerator with simultaneous MR imaging. The radiofrequency waves created by the accelerating process would degrade MR image quality, so a method for containing the radiofrequency waves and isolating the MR imager from them was developed. The linear accelerator radiofrequency modulator was placed outside the room, so a filter was designed to eliminate the radiofrequency corresponding to the proton Larmour frequency of 14.7 MHz. Placing the radiofrequency emitting components in a typical Faraday cage would have reduced the radiofrequency emissions, but the design would be susceptible to small gaps in the shield due to the efficiency of the Faraday cage reflecting internal radiofrequency emissions. To reduce internal radiofrequency reflections, the Faraday cage was lined with carbon fiber sheets. Carbon fiber has the property of attenuating the radiofrequency energy so that the overall radiofrequency field inside the Faraday cage is reduced, decreasing any radiofrequency energy emitted from small gaps in the cage walls. Results: Within a 1.2 MHz band centered on the Larmor frequency, the radiofrequency (RF) leakage from the Faraday cage was measured to be −90 dB with no RF on, −40 dB with the RF on and no shield, returning to −90 dB with the RF on and shields in place. The radiofrequency filter attenuated the linear accelerator modulator emissions in the 14.7 MHz band by 70 dB. Conclusions: One of the major challenges in designing a compact linear accelerator based MRI-guided radiation therapy system, that of isolating the high power RF system from the MRI, has been solved. The measured radiofrequency emissions are sufficiently small to enable system integration. This research was

Evaluation of microneedling fractional radiofrequency device for treatment of acne scars

Directory of Open Access Journals (Sweden)

Byalekere Shivanna Chandrashekar

2014-01-01

Full Text Available Background: Various treatment modalities including non-invasive methods such as chemical peels, topical retinoids, microdermabrasion, minimally invasive techniques such as microneedling, fractional lasers, microneedling radiofrequency devices and invasive procedures such as acne scar surgeries and ablative lasers are used for acne scars, each with its own unique advantages and disadvantages. This study is a retrospective assessment of efficacy and safety of microneedling fractional radiofrequency in the treatment of acne scars. Methods: Thirty one patients of skin types III-V with moderate and severe facial acne scarring received four sequential fractional radiofrequency treatments over a period of 6 months with an interval of 6 weeks between each session. Goodman & Baron′s acne scar grading system was used for assessment by a side by side comparison of preoperative and post- operative photographs taken at their first visit and at the end of 3 months after the last session. Results: Estimation of improvement with Goodman and Baron′s Global Acne Scarring System showed that by qualitative assessment of 31 patients with grade 3 and grade 4 acne scars, 80.64% showed improvement by 2 grades and 19.35% showed improvement by 1 grade. Quantitative assessment showed that 58% of the patients had moderate, 29% had minimal, 9% had good and 3% showed very good improvement. Adverse effects were limited to transient pain, erythema, edema and hyperpigmentation. Conclusion: Microneedling fractional radiofrequency is efficacious for the treatment of moderate and severe acne scars.

Vacuum pumping system for the JT-60 radio-frequency heating system

International Nuclear Information System (INIS)

Yokokura, Kenji; Ikeda, Yoshitaka; Imai, Tuyoshi; Suganuma, Kazuaki; Nagashima, Takashi

1988-01-01

The basic design requirements set up for the JT-60 radio-frequency heating system included: (1) rapid pumping of gas released upon application of a radio-frequency power to maintain the pressure in the launchers at 10 -2 - 10 -3 Pa or less, (2) incorporation of a gas analysis system that can operate under a strong field and high pressure (>10 -2 Pa) to permit remote controlled data collection and processing, and (3) low cost, multiple functions and high reliability. The vacuum pumping system, consisting of three units for low hybrid radio-frequency (LHRF) and one unit for ion cyclotron radio-frequency (ICRF), is connected to each launcher provided at the four ports of JT-60. The LHRF unit is composed of a main pump, an alumina joint for electrical insulation from the launcher, a metallic gate valve for isolation from the JT-60 vacuum region, and various vacuum gauges. Only a turbo-molecular pump is used for the ICRF system because a large-scale differential pumping is not required. A gas measuring system is incorporated which consists of a mass filter, personal computer, turbo-molecular pump, and variable flow valve equipped with an APG control. This system is designed to identify and make use of gas impurities released during the launcher aging process. The control system employed consists of a personal computer, interlock control board, data logger and other devices such as vacuum gages. (Nogami, K.)

Novel high-resolution temperature probe for radiofrequency dosimetry

Energy Technology Data Exchange (ETDEWEB)

Schuderer, Juergen [Foundation for Research on Information Technologies in Society (IT' IS), Integrated Systems Laboratory IIS, Swiss Federal Institute of Technology (ETH), CH-8092 Zurich (Switzerland); Schmid, Thomas [Schmid and Partner Engineering AG, 8004 Zurich (Switzerland); Urban, Gerald [IMTEK, Albert-Ludwigs University Freiburg, 79110 Freiburg (Germany); Samaras, Theodoros [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Kuster, Niels [Foundation for Research on Information Technologies in Society (IT' IS), Integrated Systems Laboratory IIS, Swiss Federal Institute of Technology (ETH), CH-8092 Zurich (Switzerland)

2004-03-21

A novel integrated thermistor probe for temperature evaluations in radiofrequency-heated environments was realized. The probe's sensitive area is based on a highly resistive 50 {mu}m x 100 {mu}m layer of amorphous germanium processed on a glass tip. The small dimensions allow measurements with a distance as close as 150 {mu}m from solid boundaries. Due to its high temperature resolution of 4 mK and its short response time of the order of 10 ms, the sensor is very well suited for dosimetric measurements in strong absorption gradients. The influence of radiofrequency (RF) electric fields on the signal is minimized due to the high resistance of the sensor and the leads. The probe was successfully used to determine the highly nonuniform absorption distribution resulting from the RF exposure of cell cultures placed in Petri dishes. (note)

Novel high-resolution temperature probe for radiofrequency dosimetry

International Nuclear Information System (INIS)

Schuderer, Juergen; Schmid, Thomas; Urban, Gerald; Samaras, Theodoros; Kuster, Niels

2004-01-01

A novel integrated thermistor probe for temperature evaluations in radiofrequency-heated environments was realized. The probe's sensitive area is based on a highly resistive 50 μm x 100 μm layer of amorphous germanium processed on a glass tip. The small dimensions allow measurements with a distance as close as 150 μm from solid boundaries. Due to its high temperature resolution of 4 mK and its short response time of the order of 10 ms, the sensor is very well suited for dosimetric measurements in strong absorption gradients. The influence of radiofrequency (RF) electric fields on the signal is minimized due to the high resistance of the sensor and the leads. The probe was successfully used to determine the highly nonuniform absorption distribution resulting from the RF exposure of cell cultures placed in Petri dishes. (note)

Analysis of ParB-centromere interactions by multiplex SPR imaging reveals specific patterns for binding ParB in six centromeres of Burkholderiales chromosomes and plasmids.

Science.gov (United States)

Pillet, Flavien; Passot, Fanny Marie; Pasta, Franck; Anton Leberre, Véronique; Bouet, Jean-Yves

2017-01-01

Bacterial centromeres-also called parS, are cis-acting DNA sequences which, together with the proteins ParA and ParB, are involved in the segregation of chromosomes and plasmids. The specific binding of ParB to parS nucleates the assembly of a large ParB/DNA complex from which ParA-the motor protein, segregates the sister replicons. Closely related families of partition systems, called Bsr, were identified on the chromosomes and large plasmids of the multi-chromosomal bacterium Burkholderia cenocepacia and other species from the order Burkholeriales. The centromeres of the Bsr partition families are 16 bp palindromes, displaying similar base compositions, notably a central CG dinucleotide. Despite centromeres bind the cognate ParB with a narrow specificity, weak ParB-parS non cognate interactions were nevertheless detected between few Bsr partition systems of replicons not belonging to the same genome. These observations suggested that Bsr partition systems could have a common ancestry but that evolution mostly erased the possibilities of cross-reactions between them, in particular to prevent replicon incompatibility. To detect novel similarities between Bsr partition systems, we have analyzed the binding of six Bsr parS sequences and a wide collection of modified derivatives, to their cognate ParB. The study was carried out by Surface Plasmon Resonance imaging (SPRi) mulitplex analysis enabling a systematic survey of each nucleotide position within the centromere. We found that in each parS some positions could be changed while maintaining binding to ParB. Each centromere displays its own pattern of changes, but some positions are shared more or less widely. In addition from these changes we could speculate evolutionary links between these centromeres.

La pelade par plaques

Science.gov (United States)

Spano, Frank; Donovan, Jeff C.

2015-01-01

Résumé Objectif Présenter aux médecins de famille des renseignements de base pour faire comprendre l’épidémiologie, la pathogenèse, l’histologie et l’approche clinique au diagnostic de la pelade par plaques. Sources des données Une recension a été effectuée dans PubMed pour trouver des articles pertinents concernant la pathogenèse, le diagnostic et le pronostic de la pelade par plaques. Message principal La pelade par plaques est une forme de perte pileuse auto-immune dont la prévalence durant une vie est d’environ 2 %. Des antécédents personnels ou familiaux de troubles auto-immuns concomitants, comme le vitiligo ou une maladie de la thyroïde, peuvent être observés dans un petit sous-groupe de patients. Le diagnostic peut souvent être posé de manière clinique en se fondant sur la perte de cheveux non cicatricielle et circulaire caractéristique, accompagnée de cheveux en « point d’exclamation » en périphérie chez ceux dont le problème en est aux premiers stades. Le diagnostic des cas plus complexes ou des présentations inhabituelles peut être facilité par une biopsie et un examen histologique. Le pronostic varie largement et de mauvais résultats sont associés à une apparition à un âge précoce, une perte importante, la variante ophiasis, des changements aux ongles, des antécédents familiaux ou des troubles auto-immuns concomitants. Conclusion La pelade par plaques est une forme auto-immune de perte de cheveux périodiquement observée en soins primaires. Les médecins de famille sont bien placés pour identifier la pelade par plaques, déterminer la gravité de la maladie et poser le diagnostic différentiel approprié. De plus, ils sont en mesure de renseigner leurs patients à propos de l’évolution clinique de la maladie ainsi que du pronostic général selon le sous-type de patients.

Keratometric alterations following the 25-gauge transconjunctival sutureless pars plana vitrectomy versus the conventional pars plana vitrectomy.

Science.gov (United States)

Citirik, Mehmet; Batman, Cosar; Bicer, Tolga; Zilelioglu, Orhan

2009-09-01

To assess the alterations in keratometric astigmatism following the 25-gauge transconjunctival sutureless pars plana vitrectomy versus the conventional pars plana vitrectomy. Sixteen consecutive patients were enrolled into the study. Conventional vitrectomy was applied to eight of the cases and 25-gauge transconjunctival sutureless vitrectomy was performed in eight patients. Keratometry was performed before and after the surgery. In the 25-gauge transconjunctival sutureless pars plana vitrectomy group, statistically significant changes were not observed in the corneal curvature in any post-operative follow-up measurement (p > 0.05); whereas in the conventional pars plana vitrectomy group, statistically significant changes were observed in the first postoperative day (p = 0.01) and first postoperative month (p = 0.03). We noted that these changes returned to baseline in three months (p = 0.26). Both 25-gauge transconjunctival sutureless and conventional pars plana vitrectomy are effective surgical modalities for selected diseases of the posterior segment. Surgical procedures are critical for the visual rehabilitation of the patients. The post-operative corneal astigmatism of the vitrectomised eyes can be accurately determined at least two months post-operatively.

Centromere pairing by a plasmid-encoded type I ParB protein

DEFF Research Database (Denmark)

Ringgaard, Simon; Löwe, Jan; Gerdes, Kenn

2007-01-01

The par2 locus of Escherichia coli plasmid pB171 encodes two trans-acting proteins, ParA and ParB, and two cis-acting sites, parC1 and parC2, to which ParB binds cooperatively. ParA is related to MinD and oscillates in helical structures and thereby positions ParB/parC-carrying plasmids regularly......, hence identifying the N terminus of ParB as a requirement for ParB-mediated centromere pairing. These observations suggest that centromere pairing is an important intermediate step in plasmid partitioning mediated by the common type I loci....

Potential health risks due to telecommunications radiofrequency ...

African Journals Online (AJOL)

Background: The global system mobile telecommunications system (GSM) which was recently introduced in Nigeria is now being used by over 40 million people in Nigeria. The use of GSM is accompanied with exposure of the users to radiofrequency radiation (RFR), which if significant, may produce health hazards. This is ...

Analysis of ParB-centromere interactions by multiplex SPR imaging reveals specific patterns for binding ParB in six centromeres of Burkholderiales chromosomes and plasmids.

Directory of Open Access Journals (Sweden)

Flavien Pillet

Full Text Available Bacterial centromeres-also called parS, are cis-acting DNA sequences which, together with the proteins ParA and ParB, are involved in the segregation of chromosomes and plasmids. The specific binding of ParB to parS nucleates the assembly of a large ParB/DNA complex from which ParA-the motor protein, segregates the sister replicons. Closely related families of partition systems, called Bsr, were identified on the chromosomes and large plasmids of the multi-chromosomal bacterium Burkholderia cenocepacia and other species from the order Burkholeriales. The centromeres of the Bsr partition families are 16 bp palindromes, displaying similar base compositions, notably a central CG dinucleotide. Despite centromeres bind the cognate ParB with a narrow specificity, weak ParB-parS non cognate interactions were nevertheless detected between few Bsr partition systems of replicons not belonging to the same genome. These observations suggested that Bsr partition systems could have a common ancestry but that evolution mostly erased the possibilities of cross-reactions between them, in particular to prevent replicon incompatibility. To detect novel similarities between Bsr partition systems, we have analyzed the binding of six Bsr parS sequences and a wide collection of modified derivatives, to their cognate ParB. The study was carried out by Surface Plasmon Resonance imaging (SPRi mulitplex analysis enabling a systematic survey of each nucleotide position within the centromere. We found that in each parS some positions could be changed while maintaining binding to ParB. Each centromere displays its own pattern of changes, but some positions are shared more or less widely. In addition from these changes we could speculate evolutionary links between these centromeres.

Non-exponential decoherence of radio-frequency resonance rotation of spin in storage rings

Science.gov (United States)

Saleev, A.; Nikolaev, N. N.; Rathmann, F.; Hinder, F.; Pretz, J.; Rosenthal, M.

2017-08-01

Precision experiments, such as the search for electric dipole moments of charged particles using radio-frequency spin rotators in storage rings, demand for maintaining the exact spin resonance condition for several thousand seconds. Synchrotron oscillations in the stored beam modulate the spin tune of off-central particles, moving it off the perfect resonance condition set for central particles on the reference orbit. Here, we report an analytic description of how synchrotron oscillations lead to non-exponential decoherence of the radio-frequency resonance driven up-down spin rotations. This non-exponential decoherence is shown to be accompanied by a nontrivial walk of the spin phase. We also comment on sensitivity of the decoherence rate to the harmonics of the radio-frequency spin rotator and a possibility to check predictions of decoherence-free magic energies.

CFD analysis of PAR performance as function of inlet design

International Nuclear Information System (INIS)

Park, Kweonha; Khor, Chong Lee

2016-01-01

Highlights: • The new concept of PAR (passive autocatalytic recombiner) was proposed and analyzed. • Guidance wall was added at the bottom of PAR to enhance the flow rate through the catalyst. • The new concept of PAR was proved to have a better hydrogen removal performance. - Abstract: Passive autocatalytic recombiner (PAR) is very useful hydrogen mitigation measurement. It is widely implemented in the current and advanced light water reactors (ALWRs). The design of the PARs should be optimized for the specific use under severe accident scenarios. Several techniques and innovations have been fused into the PAR, as an effort to increase its efficiency of hydrogen mitigation. This study proposes different concepts of PAR, which applied some changes to the honeycomb catalyst PAR made by the Korea Nuclear Technology (KNT) Inc. Two slices of plate are added to the bottom of PAR model, which intended to act as a reflection wall and promote the gas flow into PAR. Hydrogen volume fraction was given 4 vol. % which tested by KNT to investigate the performance of PAR in different direction gas flow conditions to see maximum hydrogen recombination rate. The new concept of PAR was proved to have a better hydrogen removal performance compared to the original honeycomb catalyst PAR.

CFD analysis of PAR performance as function of inlet design

Energy Technology Data Exchange (ETDEWEB)

Park, Kweonha, E-mail: khpark@kmou.ac.kr [Division of Mechanical and Energy systems Engineering, Korea Maritime University, Dongsam-dong, Yeongdo-gu, Busan 606-791 (Korea, Republic of); Khor, Chong Lee, E-mail: itachi_829@hotmail.com [Department of Mechanical Engineering, Korea Maritime University (Korea, Republic of)

2016-01-15

Highlights: • The new concept of PAR (passive autocatalytic recombiner) was proposed and analyzed. • Guidance wall was added at the bottom of PAR to enhance the flow rate through the catalyst. • The new concept of PAR was proved to have a better hydrogen removal performance. - Abstract: Passive autocatalytic recombiner (PAR) is very useful hydrogen mitigation measurement. It is widely implemented in the current and advanced light water reactors (ALWRs). The design of the PARs should be optimized for the specific use under severe accident scenarios. Several techniques and innovations have been fused into the PAR, as an effort to increase its efficiency of hydrogen mitigation. This study proposes different concepts of PAR, which applied some changes to the honeycomb catalyst PAR made by the Korea Nuclear Technology (KNT) Inc. Two slices of plate are added to the bottom of PAR model, which intended to act as a reflection wall and promote the gas flow into PAR. Hydrogen volume fraction was given 4 vol. % which tested by KNT to investigate the performance of PAR in different direction gas flow conditions to see maximum hydrogen recombination rate. The new concept of PAR was proved to have a better hydrogen removal performance compared to the original honeycomb catalyst PAR.

Comparison of microbubble presence in the right heart during mechanochemical and radiofrequency ablation for varicose veins.

Science.gov (United States)

Moon, K H; Dharmarajah, B; Bootun, R; Lim, C S; Lane, Tra; Moore, H M; Sritharan, K; Davies, A H

2017-07-01

Objective Mechanochemical ablation is a novel technique for ablation of varicose veins utilising a rotating catheter and liquid sclerosant. Mechanochemical ablation and radiofrequency ablation have no reported neurological side-effect but the rotating mechanism of mechanochemical ablation may produce microbubbles. Air emboli have been implicated as a cause of cerebrovascular events during ultrasound-guided foam sclerotherapy and microbubbles in the heart during ultrasound-guided foam sclerotherapy have been demonstrated. This study investigated the presence of microbubbles in the right heart during varicose vein ablation by mechanochemical abaltion and radiofrequency abaltion. Methods Patients undergoing great saphenous vein ablation by mechanochemical abaltion or radiofrequency ablation were recruited. During the ablative procedure, the presence of microbubbles was assessed using transthoracic echocardiogram. Offline blinded image quantification was performed using International Consensus Criteria grading guidelines. Results From 32 recruited patients, 28 data sets were analysed. Eleven underwent mechanochemical abaltion and 17 underwent radiofrequency abaltion. There were no neurological complications. In total, 39% (11/28) of patients had grade 1 or 2 microbubbles detected. Thirty-six percent (4/11) of mechanochemical abaltion patients and 29% (5/17) of radiofrequency ablation patients had microbubbles with no significant difference between the groups ( p=0.8065). Conclusion A comparable prevalence of microbubbles between mechanochemical abaltion and radiofrequency ablation both of which are lower than that previously reported for ultrasound-guided foam sclerotherapy suggests that mechanochemical abaltion may not confer the same risk of neurological events as ultrasound-guided foam sclerotherapy for treatment of varicose veins.

Par Pond Fish, Water, and Sediment Chemistry

International Nuclear Information System (INIS)

Paller, M.H.; Wike, L.D.

1996-06-01

The objectives of this report are to describe the Par Pond fish community and the impact of the drawdown and refill on the community, describe contaminant levels in Par Pond fish, sediments, and water and indicate how contaminant concentrations and distributions were affected by the drawdown and refill, and predict possible effects of future water level fluctuations in Par Pond

Par Pond Fish, Water, and Sediment Chemistry

Energy Technology Data Exchange (ETDEWEB)

Paller, M.H. [Westinghouse Savannah River Company, AIKEN, SC (United States); Wike, L.D.

1996-06-01

The objectives of this report are to describe the Par Pond fish community and the impact of the drawdown and refill on the community, describe contaminant levels in Par Pond fish, sediments, and water and indicate how contaminant concentrations and distributions were affected by the drawdown and refill, and predict possible effects of future water level fluctuations in Par Pond.

Efficacy of inferior turbinoplasty with the use of CO(2) laser, radiofrequency, and electrocautery.

Science.gov (United States)

Prokopakis, Emmanuel P; Koudounarakis, Eleftherios I; Velegrakis, George A

2014-01-01

Inferior turbinate surgery is one of the most commonly performed methods for the treatment of rhinitis symptoms, especially nasal obstruction. This is a comparative study of CO2 laser, electrocautery, and radiofrequency turbinoplasty in the treatment of rhinitis symptoms. From 1994 to 2011, 3219 patients were enrolled in the study. Two hundred eighty-three patients were lost during follow-.up. Of the remaining 2936 patients, 1066 were managed using the CO2 laser, whereas 664 and 1206 were managed with the use of radiofrequency and electrocautery, respectively. All procedures were performed under local anesthesia. Patients were asked to evaluate their symptoms with the visual analog scale (VAS) preoperatively, as well as 1 month and 1 year postoperatively. Rhinomanometry was used to objectively evaluate the effect on nasal obstruction. Mean VAS values preoperatively, regarding nasal obstruction, were 7.43 ± 0.96, 7.33 ± 0.87, and 7.64 ± 0.95 in the CO2 laser, radiofrequency, and electrocautery group, respectively. One month postoperatively, the score was significantly improved in all groups (CO2 laser, 3.44 ± 0.99; radiofrequency, 3.26 ± 0.76; electrocautery, 3.19 ± 0.79), which was almost stable in the 1st year of follow-up. Similar results were also observed in the evaluation of sneezing and rhinorrhea. Outcome did not statistically differ between the three methods. The CO2 laser, radiofrequency and electrocautery offer excellent postoperative results in turbinoplasty cases under local anesthesia.

Concerning the dynamic instability of actin homolog ParM

International Nuclear Information System (INIS)

Popp, David; Yamamoto, Akihiro; Iwasa, Mitsusada; Narita, Akihiro; Maeda, Kayo; Maeda, Yuichiro

2007-01-01

Using in vitro TIRF- and electron-microscopy, we reinvestigated the dynamics of native ParM, a prokaryotic DNA segregation protein and actin homolog. In contrast to a previous study, which used a cysteine ParM mutant, we find that the polymerization process of wild type ATP-ParM filaments consists of a polymerization phase and a subsequent steady state phase, which is dynamically unstable, like that of microtubules. We find that the apparent bidirectional polymerization of ParM, is not due to the intrinsic nature of this filament, but results from ParM forming randomly oriented bundles in the presence of crowding agents. Our results imply, that in the bacterium, ParM filaments spontaneously form bipolar bundles. Due to their intrinsic dynamic instability, ParM bundles can efficiently 'search' the cytoplasmic lumen for DNA, bind it equally well at the bipolar ends and segregate it approximately symmetrically, by the insertion of ParM subunits at either end

First-in-human uPAR PET

DEFF Research Database (Denmark)

Persson, Morten; Skovgaard, Dorthe; Brandt-Larsen, Malene

2015-01-01

A first-in-human clinical trial with Positron Emission Tomography (PET) imaging of the urokinase-type plasminogen activator receptor (uPAR) in patients with breast, prostate and bladder cancer, is described. uPAR is expressed in many types of human cancers and the expression is predictive...... for targeted molecular imaging with PET. The safety, pharmacokinetic, biodistribution profile and radiation dosimetry after a single intravenous dose of (64)Cu-DOTA-AE105 were assessed by serial PET and computed tomography (CT) in 4 prostate, 3 breast and 3 bladder cancer patients. Safety assessment...... of invasion, metastasis and indicates poor prognosis. uPAR PET imaging therefore holds promise to be a new and innovative method for improved cancer diagnosis, staging and individual risk stratification. The uPAR specific peptide AE105 was conjugated to the macrocyclic chelator DOTA and labeled with (64)Cu...

Use of Radiofrequency Ablation in Benign Thyroid Nodules: A Literature Review and Updates

OpenAIRE

Wong, KP; Lang, HHB

2013-01-01

Successful thermal ablation using radiofrequency has been reported in various tumors including liver or kidney tumors. Nonsurgical minimally invasive ablative therapy such as radiofrequency ablation (RFA) has been reported to be a safe and efficient treatment option in managing symptomatic cold thyroid nodules or hyperfunctioning thyroid nodules. Pressure and cosmetic symptoms have been shown to be significantly improved both in the short and long terms after RFA. For hyperfunctioning thyroid...

Length of Barrett's segment predicts failure of eradication in radiofrequency ablation for Barrett's esophagus: a retrospective cohort study.

Science.gov (United States)

Luckett, Tyler; Allamneni, Chaitanya; Cowley, Kevin; Eick, John; Gullick, Allison; Peter, Shajan

2018-05-21

We aim to investigate factors that may contribute to failure of eradication of dysplastic Barrett's Esophagus among patients undergoing radiofrequency ablation treatment. A retrospective review of patients undergoing radiofrequency ablation for treatment of Barrett's Esophagus was performed. Data analyzed included patient demographics, medical history, length of Barrett's Esophagus, number of radiofrequency ablation sessions, and histopathology. Subsets of patients achieving complete eradication were compared with those not achieving complete eradication. A total of 107 patients underwent radiofrequency ablation for Barrett's Esophagus, the majority white, overweight, and male. Before treatment, 63 patients had low-grade dysplasia, and 44 patients had high-grade dysplasia or carcinoma. Complete eradication was achieved in a majority of patients (57% for metaplasia, and 76.6% for dysplasia). Failure of eradication occurred in 15.7% of patients. The median number of radiofrequency ablation treatments in patients achieving complete eradication was 3 sessions, compared to 4 sessions for failure of eradication (p = 0.06). Barrett's esophagus length of more than 5 cm was predictive of failure of eradication (p Radiofrequency ablation for dysplastic Barrett's Esophagus is a proven and effective treatment modality, associated with a high rate of complete eradication. Our rates of eradication from a center starting an ablation program are comparable to previously published studies. Length of Barrett's segment > 5 cm was found to be predictive of failure of eradication in patients undergoing radiofrequency ablation.

Localization of alpha emitters by damage production in a thin film. Application to the study of alpha emitter diffusion in irradiated samples; Localisation des emetteurs alpha par creation de dommages dans un film mince. Application a l'etude de la diffusion des emetteurs alpha dans des echantillons irradies

Energy Technology Data Exchange (ETDEWEB)

Houdaille, B; Perrot, M [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

1968-07-01

comprise entre 0.5 et 4 MeV, il a tout d'abord fallu determiner le rendement de l'enregistreur pour les particules alpha emises par une source epaisse, c'est-a-dire dont l'energie varie entre O et E{sub 0}, E{sub 0} etant l'energie de l'emetteur alpha. - La concentration C de l'emetteur alpha, en fonction de la densite optique D de l' alphagraphie, et du temps de pose t, est donnee par une formule simple: C = D/at ou a est une constante experimentale, determinee par etalonnage. Elle depend de la nature du nitrate de cellulose, de l'element emetteur alpha et de l'alliage etudie. (auteurs)

uPAR as anti-cancer target

DEFF Research Database (Denmark)

Lund, Ida K; Illemann, Martin; Thurison, Tine

2011-01-01

, and a potential diagnostic and predictive impact of the different uPAR forms has been reported. Hence, pericellular proteolysis seems to be a suitable target for anti-cancer therapy and numerous approaches have been pursued. Targeting of this process may be achieved by preventing the binding of uPA to u...... using mouse monoclonal antibodies (mAbs) against mouse uPA or uPAR. These reagents will target uPA and uPAR in both stromal cells and cancer cells, and their therapeutic potential can now be assessed in syngenic mouse cancer models....

Treatment of Décolletage Photoaging With Fractional Microneedling Radiofrequency.

Science.gov (United States)

Lyons, Alexis; Roy, Jillian; Herrmann, Jennifer; Chipps, Lisa

2018-01-01

The objective of this study was to examine the efficacy and safety of a novel fractional microneedling radiofrequency device to improve the appearance of rhytides and skin laxity of the décolletage. Twelve subjects received a total of three fractional microneedling radiofrequency treatments with Endymed Intensif (EndyMed Ltd., Cesarea, Israel) at least three weeks apart. Primary outcome measure was clinical efficacy quantified by a patient survey to assess treatment satisfaction as well as a physician Global Aesthetic Improvement Scale (GAIS). Photos were taken before every treatment and at a follow-up appointment. Assessments by two board-certified dermatologists revealed an overall improvement in 67% of patients. Seventy percent of subjects rated their post-treatment skin laxity and rhytides as improved, while 60% of patients rated their skin texture as improved. Eighty percent of subjects were at least slightly satisfied with their treatment. Forty percent of subjects would recommend this treatment to others. Subjects in this study demonstrated an overall improvement in décolletage appearance in regard to skin tightening, wrinkles, and skin texture suggested by overall patient satisfaction (80%) and physician-rated GAIS improvement (67%). This study suggests that fractional microneedling radiofrequency devices are a safe and efficacious way to improve overall décolletage appearance with little down time. J Drugs Dermatol. 2018;17(1):74-76..

Radiofrequency radiation

International Nuclear Information System (INIS)

Elder, J.A.; Czerski, P.A.; Stuchly, M.A.; Mild, K.H.; Sheppard, A.R.

1989-01-01

High-level radiofrequency radiation is a source of thermal energy that carries all of the known implications of heating for biological systems, including burns, temporary and permanent changes in reproduction, cataracts, and death. In general, no changes in chromosomes, DNA or the reproductive potential of animals exposed to RF radiation have been reported in the absence of significant rises in temperature, though there are limited data on DNA and chromosomal changes at non-thermal levels. Human data are currently limited and do not provide adequate information about the relationship between prolonged low-level RF radiation exposure and increased mortality or morbidity, including cancer incidence. In epidemiological studies and clinical reports of RF effects in man, the problems of quantification are numerous and include uncertainties about ''dose'', health effects, latent periods, dose-response relationships, and interactions with other physical or chemical agents. 228 refs, 6 figs, 2 tabs

Mitral valve perforation appearing years after radiofrequency ablation

DEFF Research Database (Denmark)

Fisch-Thomsen, Marie; Jensen, Jesper K; Egeblad, Henrik

2011-01-01

The case is reported of a young adult with Wolff-Parkinson-White (WPW) syndrome who, three years after a complicated radiofrequency (RF) catheter ablation procedure, developed dyspnea on exertion. Echocardiography revealed severe mitral valve regurgitation caused by a perforation of the posterior...

Radiofrequency solutions in clinical high field magnetic resonance

NARCIS (Netherlands)

Andreychenko, A.

2013-01-01

Magnetic resonance imaging (MRI) and spectroscopy (MRS) benefit from the sensitivity gain at high field (≥7T). However, high field brings also certain challenges associated with growing frequency and spectral dispersion. Frequency growth results in degraded performance of large volume radiofrequency

Endovascular ultrasound for renal sympathetic denervation in patients with therapy-resistant hypertension not responding to radiofrequency renal sympathetic denervation.

Science.gov (United States)

Stiermaier, Thomas; Okon, Thomas; Fengler, Karl; Mueller, Ulrike; Hoellriegel, Robert; Schuler, Gerhard; Desch, Steffen; Lurz, Philipp

2016-06-12

Recent studies have reported a considerable number of non-responders after renal sympathetic de-nervation (RSD) with radiofrequency technology. Here we report our results of repeat RSD using ultrasound in these patients. A cohort study was performed in patients who underwent ultrasound RSD after non-response to RSD with radiofrequency. Non-response was defined as mean daytime systolic blood pressure ≥140 mmHg and/or a reduction of ≤10 mmHg in ambulatory blood pressure measurement (ABPM) ≥6 months after radiofrequency denervation. ABPM was recorded at baseline, post radiofrequency RSD as well as at three and six months post ultrasound RSD. A total of 24 non-responders underwent retreatment with the ultrasound device at a mean 15.3±8.2 months after radiofrequency RSD. Ultrasound RSD was performed successfully in all patients without severe adverse events. Mean daytime systolic blood pressure changed from 161.7±14.6 mmHg at baseline to 158.5±9.5 mmHg post radiofrequency RSD and to 150.5±10.4 mmHg and 151.6±11.0 mmHg at three and six months, respectively, post ultrasound RSD (pmeasures analysis of variance). The main results of post hoc testing were as follows: baseline versus post radiofrequency RSD, p=0.83; baseline versus three months post ultrasound RSD, p=0.01; and baseline versus six months post ultrasound RSD, p=0.04. Ultrasound RSD appears to be safe and an effective therapeutic approach in patients not responding to previous RSD with radiofrequency technology.

Comparison of QuadrapolarTM radiofrequency lesions produced by standard versus modified technique: an experimental model

Directory of Open Access Journals (Sweden)

Safakish R

2017-06-01

Full Text Available Ramin Safakish Allevio Pain Management Clinic, Toronto, ON, Canada Abstract: Lower back pain (LBP is a global public health issue and is associated with substantial financial costs and loss of quality of life. Over the years, different literature has provided different statistics regarding the causes of the back pain. The following statistic is the closest estimation regarding our patient population. The sacroiliac (SI joint pain is responsible for LBP in 18%–30% of individuals with LBP. Quadrapolar™ radiofrequency ablation, which involves ablation of the nerves of the SI joint using heat, is a commonly used treatment for SI joint pain. However, the standard Quadrapolar radiofrequency procedure is not always effective at ablating all the sensory nerves that cause the pain in the SI joint. One of the major limitations of the standard Quadrapolar radiofrequency procedure is that it produces small lesions of ~4 mm in diameter. Smaller lesions increase the likelihood of failure to ablate all nociceptive input. In this study, we compare the standard Quadrapolar radiofrequency ablation technique to a modified Quadrapolar ablation technique that has produced improved patient outcomes in our clinic. The methodology of the two techniques are compared. In addition, we compare results from an experimental model comparing the lesion sizes produced by the two techniques. Taken together, the findings from this study suggest that the modified Quadrapolar technique provides longer lasting relief for the back pain that is caused by SI joint dysfunction. A randomized controlled clinical trial is the next step required to quantify the difference in symptom relief and quality of life produced by the two techniques. Keywords: lower back pain, radiofrequency ablation, sacroiliac joint, Quadrapolar radiofrequency ablation

Protease-activated receptor (PAR2, but not PAR1, is involved in collateral formation and anti-inflammatory monocyte polarization in a mouse hind limb ischemia model.

Directory of Open Access Journals (Sweden)

Lisa G van den Hengel

Full Text Available AIMS: In collateral development (i.e. arteriogenesis, mononuclear cells are important and exist as a heterogeneous population consisting of pro-inflammatory and anti-inflammatory/repair-associated cells. Protease-activated receptor (PAR1 and PAR2 are G-protein-coupled receptors that are both expressed by mononuclear cells and are involved in pro-inflammatory reactions, while PAR2 also plays a role in repair-associated responses. Here, we investigated the physiological role of PAR1 and PAR2 in arteriogenesis in a murine hind limb ischemia model. METHODS AND RESULTS: PAR1-deficient (PAR1-/-, PAR2-deficient (PAR2-/- and wild-type (WT mice underwent femoral artery ligation. Laser Doppler measurements revealed reduced post-ischemic blood flow recovery in PAR2-/- hind limbs when compared to WT, while PAR1-/- mice were not affected. Upon ischemia, reduced numbers of smooth muscle actin (SMA-positive collaterals and CD31-positive capillaries were found in PAR2-/- mice when compared to WT mice, whereas these parameters in PAR1-/- mice did not differ from WT mice. The pool of circulating repair-associated (Ly6C-low monocytes and the number of repair-associated (CD206-positive macrophages surrounding collaterals in the hind limbs were increased in WT and PAR1-/- mice, but unaffected in PAR2-/- mice. The number of repair-associated macrophages in PAR2-/- hind limbs correlated with CD11b- and CD115-expression on the circulating monocytes in these animals, suggesting that monocyte extravasation and M-CSF-dependent differentiation into repair-associated cells are hampered. CONCLUSION: PAR2, but not PAR1, is involved in arteriogenesis and promotes the repair-associated response in ischemic tissues. Therefore, PAR2 potentially forms a new pro-arteriogenic target in coronary artery disease (CAD patients.

Complications associated with radiofrequency ablation of pulmonary veins.

Science.gov (United States)

Madrid Pérez, J M; García Barquín, P M; Villanueva Marcos, A J; García Bolao, J I; Bastarrika Alemañ, G

Radiofrequency ablation is an efficacious alternative in patients with symptomatic atrial fibrillation who do not respond to or are intolerant to at least one class I or class III antiarrhythmic drug. Although radiofrequency ablation is a safe procedure, complications can occur. Depending on the location, these complications can be classified into those that affect the pulmonary veins themselves, cardiac complications, extracardiac intrathoracic complications, remote complications, and those that result from vascular access. The most common complications are hematomas, arteriovenous fistulas, and pseudoaneurysms at the puncture site. Some complications are benign and transient, such as gastroparesis or diaphragmatic elevation, whereas others are potentially fatal, such as cardiac tamponade. Radiologists must be familiar with the complications that can occur secondary to pulmonary vein ablation to ensure early diagnosis and treatment. Copyright © 2016 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Apoplejía pituitaria con parálisis del III par craneal: Reporte de caso

Directory of Open Access Journals (Sweden)

Miguel Pinto Valdivia

2011-10-01

Full Text Available Se describe el caso de un varón de 65 años de edad, sin antecedentes patológicos de importancia, que acudió a emergencia del Hospital Nacional Cayetano Heredia por presentar cefalea intensa y ptosis palpebral izquierda. El examen físico mostró parálisis aislada del III par craneal izquierdo. Los análisis de laboratorio mostraron hiponatremia e hipopituitarismo y la resonancia magnética nuclear un adenoma pituitario con áreas de hemorragia e invasión de los senos cavernosos. El tratamiento incluyó glucocorticoides y descompresión quirúrgica transesfenoidal. La anatomía patológica confirmó el diagnóstico de infarto hemorrágico de un adenoma pituitario. El paciente fue dado de alta con terapia sustitutiva de levotiroxina y prednisona. La ptosis palpebral izquierda se recuperó en forma parcial. La apoplejía pituitaria es un síndrome clínico producido por un proceso expansivo dentro de la silla turca, secundario a hemorragia o infarto de un adenoma pituitario, que se caracteriza por cefalea, déficit visual, oftalmoplejía y alteración del nivel de conciencia. Este proceso expansivo puede comprimir los pares craneales en los senos cavernosos, produciendo diferentes grados de parálisis de los músculos oculomotores. La parálisis aislada del III par craneal es rara.(Rev Med Hered 2011;22:186-189.

Copenhagen uPAR prostate cancer (CuPCa) database

DEFF Research Database (Denmark)

Lippert, Solvej; Berg, Kasper D; Høyer-Hansen, Gunilla

2016-01-01

AIM: Urokinase plasminogen activator receptor (uPAR) plays a central role during cancer invasion by facilitating pericellular proteolysis. We initiated the prospective 'Copenhagen uPAR Prostate Cancer' study to investigate the significance of uPAR levels in prostate cancer (PCa) patients. METHODS...

Recombination in the human Pseudoautosomal region PAR1.

Directory of Open Access Journals (Sweden)

Anjali G Hinch

2014-07-01

Full Text Available The pseudoautosomal region (PAR is a short region of homology between the mammalian X and Y chromosomes, which has undergone rapid evolution. A crossover in the PAR is essential for the proper disjunction of X and Y chromosomes in male meiosis, and PAR deletion results in male sterility. This leads the human PAR with the obligatory crossover, PAR1, to having an exceptionally high male crossover rate, which is 17-fold higher than the genome-wide average. However, the mechanism by which this obligatory crossover occurs remains unknown, as does the fine-scale positioning of crossovers across this region. Recent research in mice has suggested that crossovers in PAR may be mediated independently of the protein PRDM9, which localises virtually all crossovers in the autosomes. To investigate recombination in this region, we construct the most fine-scale genetic map containing directly observed crossovers to date using African-American pedigrees. We leverage recombination rates inferred from the breakdown of linkage disequilibrium in human populations and investigate the signatures of DNA evolution due to recombination. Further, we identify direct PRDM9 binding sites using ChIP-seq in human cells. Using these independent lines of evidence, we show that, in contrast with mouse, PRDM9 does localise peaks of recombination in the human PAR1. We find that recombination is a far more rapid and intense driver of sequence evolution in PAR1 than it is on the autosomes. We also show that PAR1 hotspot activities differ significantly among human populations. Finally, we find evidence that PAR1 hotspot positions have changed between human and chimpanzee, with no evidence of sharing among the hottest hotspots. We anticipate that the genetic maps built and validated in this work will aid research on this vital and fascinating region of the genome.

A hybrid polarization-selective atomic sensor for radio-frequency field detection with a passive resonant-cavity field amplifier

OpenAIRE

Anderson, David A.; Paradis, Eric G.; Raithel, Georg

2018-01-01

We present a hybrid atomic sensor that realizes radio-frequency electric field detection with intrinsic field amplification and polarization selectivity for robust high-sensitivity field measurement. The hybrid sensor incorporates a passive resonator element integrated with an atomic vapor cell that provides amplification and polarization selectivity for detection of incident radio-frequency fields. The amplified intra-cavity radio-frequency field is measured by atoms using a quantum-optical ...

Endoscopic release of congenital muscular torticollis with radiofrequency in teenagers.

Science.gov (United States)

Wang, Jun-Liang; Qi, Wei; Liu, Yu-Jie

2018-05-03

Congenital muscular torticollis (CMT) is due to contracture of the sternocleidomastoid muscle which may cause activity limitations of the neck, tilt of the head, craniofacial asymmetry, and deformity of the skull. The authors present their experience of arthroscopic tight fibrous band release with radiofrequency in teenagers under local anesthesia and evaluate the clinical results. A total of 69 patients who underwent arthroscopic release of CMT with radiofrequency under local anesthesia by a single surgeon could participate in this study. Before operation, surface landmarks of sternocleidomastoid muscle, bone, and neurovascular structures were marked. Local infiltrating anesthesia of the surgical region was then performed. Through a working space created by blunt dissection, the arthroscopy and radiofrequency devices were introduced. Then, the clavicular and sternal heads of the sternocleidomastoid muscle were identified and gradually transected. The patients were followed up postoperatively with Cheng's scoring system. There were 31 male patients and 38 female patients. The mean age of the patients was 16.1 years. The mean length of follow-up in this series was 36.7 months (range, 28 to 67 months). During the operation, 62 patients (89.9%) had no pain, 6 patients (8.7%) felt mild pain, and only 1 patient (1.4%) regarded the procedure as very painful. At all follow-up periods, there were no repeat arthroscopies for any of these patients. At the final follow-up, the average rotation deficit improved from 22.5° to 4.1° postoperatively, and the average lateral bending deficit improved from 14.6° to 3.3° (p radiofrequency under local anesthesia provides surgeons with an alternative to traditional open techniques for the management of congenital muscular torticollis (CMT). Our date shows that this method is minimally invasive and provides good functional recovery with a lower risk of complications.

Measurement of intrahepatic pressure during radiofrequency ablation in porcine liver.

Science.gov (United States)

Kawamoto, Chiaki; Yamauchi, Atsushi; Baba, Yoko; Kaneko, Keiko; Yakabi, Koji

2010-04-01

To identify the most effective procedures to avoid increased intrahepatic pressure during radiofrequency ablation, we evaluated different ablation methods. Laparotomy was performed in 19 pigs. Intrahepatic pressure was monitored using an invasive blood pressure monitor. Radiofrequency ablation was performed as follows: single-step standard ablation; single-step at 30 W; single-step at 70 W; 4-step at 30 W; 8-step at 30 W; 8-step at 70 W; and cooled-tip. The array was fully deployed in single-step methods. In the multi-step methods, the array was gradually deployed in four or eight steps. With the cooled-tip, ablation was performed by increasing output by 10 W/min, starting at 40 W. Intrahepatic pressure was as follows: single-step standard ablation, 154.5 +/- 30.9 mmHg; single-step at 30 W, 34.2 +/- 20.0 mmHg; single-step at 70 W, 46.7 +/- 24.3 mmHg; 4-step at 30 W, 42.3 +/- 17.9 mmHg; 8-step at 30 W, 24.1 +/- 18.2 mmHg; 8-step at 70 W, 47.5 +/- 31.5 mmHg; and cooled-tip, 114.5 +/- 16.6 mmHg. The radiofrequency ablation-induced area was spherical with single-step standard ablation, 4-step at 30 W, and 8-step at 30 W. Conversely, the ablated area was irregular with single-step at 30 W, single-step at 70 W, and 8-step at 70 W. The ablation time was significantly shorter for the multi-step method than for the single-step method. Increased intrahepatic pressure could be controlled using multi-step methods. From the shapes of the ablation area, 30-W 8-step expansions appear to be most suitable for radiofrequency ablation.

Simplified method for esophagus protection during radiofrequency catheter ablation of atrial fibrillation - prospective study of 704 cases

Science.gov (United States)

Mateos, José Carlos Pachón; Mateos, Enrique I Pachón; Peña, Tomas G Santillana; Lobo, Tasso Julio; Mateos, Juán Carlos Pachón; Vargas, Remy Nelson A; Pachón, Carlos Thiene C; Acosta, Juán Carlos Zerpa

2015-01-01

Introduction Although rare, the atrioesophageal fistula is one of the most feared complications in radiofrequency catheter ablation of atrial fibrillation due to the high risk of mortality. Objective This is a prospective controlled study, performed during regular radiofrequency catheter ablation of atrial fibrillation, to test whether esophageal displacement by handling the transesophageal echocardiography transducer could be used for esophageal protection. Methods Seven hundred and four patients (158 F/546M [22.4%/77.6%]; 52.8±14 [17-84] years old), with mean EF of 0.66±0.8 and drug-refractory atrial fibrillation were submitted to hybrid radiofrequency catheter ablation (conventional pulmonary vein isolation plus AF-Nests and background tachycardia ablation) with displacement of the esophagus as far as possible from the radiofrequency target by transesophageal echocardiography transducer handling. The esophageal luminal temperature was monitored without and with displacement in 25 patients. Results The mean esophageal displacement was 4 to 9.1cm (5.9±0.8 cm). In 680 of the 704 patients (96.6%), it was enough to allow complete and safe radiofrequency delivery (30W/40ºC/irrigated catheter or 50W/60ºC/8 mm catheter) without esophagus overlapping. The mean esophageal luminal temperature changes with versus without esophageal displacement were 0.11±0.13ºC versus 1.1±0.4ºC respectively, P<0.01. The radiofrequency had to be halted in 68% of the patients without esophageal displacement because of esophageal luminal temperature increase. There was no incidence of atrioesophageal fistula suspected or confirmed. Only two superficial bleeding caused by transesophageal echocardiography transducer insertion were observed. Conclusion Mechanical esophageal displacement by transesophageal echocardiography transducer during radiofrequency catheter ablation was able to prevent a rise in esophageal luminal temperature, helping to avoid esophageal thermal lesion. In most

Administrative norms on radiofrequency radiation for occupationally exposed persons

International Nuclear Information System (INIS)

Saxeboel, G.

1982-01-01

The report presents a proposal for administrative norms on radiofrequency (RF) radiation for occupationally exposed persons. The norms establish maximum allowable field exposure in a frequency range from 1 MHz too 300 GHz. (RF)

Bilateral occipital lobe infarction with altitudinal field loss following radiofrequency cardiac catheter ablation

Directory of Open Access Journals (Sweden)

Chen Celia S

2010-03-01

Full Text Available Abstract Background Bilateral stroke following radiofrequency catheter ablation is an unusual complication and may result in bilateral altitudinal visual field defects. Bilateral altitudinal visual field defects usually result from prechiasmal pathology causing damage to both retinas or optic nerves and rarely from bilateral symmetric damage to the post chiasmal visual pathways. Case presentation A 48-year-old man complained of visual disturbance on wakening following radiofrequency catheter ablation. The patient had a CHADS score of 1 pre-operatively and no complications were noted intra-operatively. Examination revealed a bilateral superior altitudinal defect and MRI of the brain showed multifocal areas of infarction predominantly involving the occipital lobes which correlated to with the visual deficits. Conclusion While the risk of thromboembolism and perioperative stroke during radiofrequency catheter ablation is small, it is not insignificant.

Neurohumoral indicators of efficacy radiofrequency cardiac denervation

Energy Technology Data Exchange (ETDEWEB)

Evtushenko, A. V., E-mail: ave@cardio-tomsk.ru; Evtushenko, V. V. [National Research Tomsk State University, Tomsk (Russian Federation); Federal State Budgetary Scientific Institution “Research Institute for Cardiology”, Tomsk (Russian Federation); Saushkina, Yu. V.; Gusakova, A. M.; Suslova, T. E.; Dymbrylova, O. N.; Smyshlyaev, K. A.; Kurlov, I. O. [Federal State Budgetary Scientific Institution “Research Institute for Cardiology”, Tomsk (Russian Federation); Lishmanov, Yu. B.; Anfinogenova, Ya. D. [National Research Tomsk Polytechnic University, Tomsk (Russian Federation); Federal State Budgetary Scientific Institution “Research Institute for Cardiology”, Tomsk (Russian Federation); Sergeevichev, D. S. [Academician E.N. Meshalkin State Research Institute of Circulation Pathology, Novosibirsk (Russian Federation); Bykov, A. N.; Syryamkin, V. I.; Kistenev, Yu. V. [National Research Tomsk State University, Tomsk (Russian Federation); Lotkov, A. I. [Institute of Strength Physics and Materials Science of the Siberian Branch of the RAS, Tomsk (Russian Federation); Pokushalov, E. A.

2015-11-17

In this study, we compared pre- and postoperative parameters of the cardiac sympathetic innervation. The aim of the study was to examine the approaches to evaluating the quality of radiofrequency (RF)-induced cardiac denervation by using non-invasive and laboratory methods. The study included 32 people with long-lasting persistent atrial fibrillation (AF). The patients were divided into 2 groups according to the objectives of the study: group 1 (main) - 21 patients with mitral valve diseases, which simultaneously with radiofrequency ablation (RFA) AF carried out on the effects of the paraganglionic nervous plexuses by C. Pappone (2004) and N. Doll (2008) schemes. The second group (control) contained 11 patients with heart diseases in sinus rhythm (the RF denervation not been performed). All patients, who underwent surgical treatment, were received examination of cardiac sympathetic tone by using {sup 123}I-MIBG. All of them made blood analysis from ascending aorta and coronary sinus to determine the level of norepinephrine and its metabolites before and after cardiac denervation. Data of radionuclide examination are correlating with laboratory data.

Plasma suPAR is lowered by smoking cessation

DEFF Research Database (Denmark)

Eugen-Olsen, Jesper; Ladelund, Steen; Sørensen, Lars Tue

2016-01-01

BACKGROUND: Soluble urokinase plasminogen activator receptor (suPAR) is a stable inflammatory biomarker. In patients, suPAR is a marker of disease presence, severity and prognosis. In the general population, suPAR is predictive of disease development, such as diabetes and cardiovascular disease a...

Isotope analysis by emission spectroscopy; Analyse isotopique par spectroscopie d'emission

Energy Technology Data Exchange (ETDEWEB)

Artaud, J; Gerstenkorn, S [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Blaise, J [Centre National de la Recherche Scientifique (CNRS), Lab. Aime Cotton, 92 - Meudon-Bellevue (France)

1959-07-01

Quantitative analysis of isotope mixtures by emission spectroscopy is resulting from the phenomenon called 'isotope shift', say from the fact that spectral lines produced by a mixture of isotopes of a same element are complex. Every spectral line is, indeed, resulting from several lines respectively corresponding to each isotope. Then isotopic components are near one to others, and their separation is effected by means of Fabry-Perot calibration standard: the apparatus allowing to measure abundances is the Fabry-Perot photo-electric spectrometer, designed in 1948 by MM. JACQUINOT and DUFOUR. This method has been used to make abundance determination in the case of helium, lithium, lead and uranium. In the case of lithium, the utilised analysis line depends on the composition of examined isotopic mixture. For mixtures containing 7 to 93 pour cent of one of isotopes of lithium, this line is the lithium blue line: {lambda} = 4603 angstrom. In other cases the red line {lambda} = 6707 angstrom is preferable, though it allows to do easily nothing but relative determinations. Helium shows no particular difficulty and the analysis line selected was {lambda} = 6678 angstrom. For lead the line {lambda} = 5201 angstrom gives the possibility to determine the isotope abundance for the four isotopes of lead notwithstanding the presence of hyperfine structure of {sup 207}Pb. For uranium, line {lambda} 5027 angstrom is used, and this method allows to determine the composition of isotope mixtures, the content of which in {sup 235}U may shorten to 0,1 per cent. Relative precision is about 2 per cent for contents in {sup 235}U over 1 per cent. For lower contents, this line {lambda} = 5027 angstrom will allow relative measures when using previously dosed mixtures. (author) [French] L'analyse quantitative des melanges isotopiques par spectroscopie d'emission doit son existence au phenomene appele 'deplacement isotopique', c'est-a-dire au fait que les raies spectrales emises par un

Health Impacts Of Radiofrequency Exposure From Mobile Phone ...

African Journals Online (AJOL)

Background: The widespread use of mobile phones and indiscriminate siting of transmitter base stations near residential buildings in our environment may have serious health impacts. Objective: To investigate the possible health risks associated with radiofrequency (RF) exposure from mobile phones and other transmitter ...

Poloidally asymmetric potential increases in tokamak scrape-off layer plasmas by radiofrequency power

International Nuclear Information System (INIS)

Diebold, D.A.; Majeski, R.; Tanaka, T.

1992-01-01

Langmuir probe data are presented which show poloidally asymmetric increases in floating potential, electron temperature and, hence, plasma potential on magnetic field lines which map to the Faraday shield of an ICRF antenna in a medium size tokamak, Phaedrus-T, during radiofrequency power injection. These data are consistent with and suggestive of the existence of radiofrequency generated sheath voltages on those field lines. (author). Letter-to-the-editor. 20 refs, 3 figs

Non-destructive radio-frequency and microwave measurement of moisture content in agricultural commodities

International Nuclear Information System (INIS)

Nelson, S.O.

1994-01-01

The importance of moisture content in agricultural commodities, the usefulness of the dielectric properties of such products for sensing moisture content by radiofrequency and microwave measurements, and factors affecting these properties are briefly discussed. Recent developments in the understanding of principles for online moisture sensing and the sensing of individual kernel, seed, nut and fruit moisture contents by radiofrequency and microwave techniques are reviewed. A brief discussion is included on aspects of practical application

Isotope Analysis of Uranium by Interferometry; Analyse isotopique de l'uranium par interferometrie

Energy Technology Data Exchange (ETDEWEB)

Leicknam, J P [Commissariat a l' Energie Atomique. Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

1962-07-01

Among the optical methods which may be used to make isotopic measurements of {sup 235}U interferometry gives promising results. An apparatus is described which has a photomultiplier as receiver; the source must therefore have characteristics (intensity, stability, fineness of emitted rays) which have led to the use of electrode-less discharge tubes whose methods of production and excitation are given. An example of calibration is given. (author) [French] Parmi les methodes optiques permettant le dosage isotopique de l'uranium 235, l'interferometrie est une technique qui donne des resultats prometteurs. On decrit ici un appareil ayant un photo-multiplicateur comme recepteur; la source doit donc avoir des caracteristiques (intensite, stabilite, finesse des raies emises) qui ont conduit a utiliser des tubes a decharge sans electrode dont on indique la fabrication et le mode d'excitation. Un exemple d'etalonnage est enfin donne. (auteur)

Arrhythmia-free survival and pulmonary vein reconnection patterns after second-generation cryoballoon and contact-force radiofrequency pulmonary vein isolation.

Science.gov (United States)

Buist, Thomas J; Adiyaman, Ahmet; Smit, Jaap Jan J; Ramdat Misier, Anand R; Elvan, Arif

2018-06-01

The aim of this study was to compare second-generation cryoballoon and contact-force radiofrequency point-by-point pulmonary vein isolation (PVI) in atrial fibrillation (AF) patients with regard to pulmonary vein reconnection and arrhythmia-free survival. Altogether, 269 consecutive patients with drug-refractory AF undergoing PVI were included and randomly allocated to second-generation cryoballoon or contact-force point-by-point radiofrequency ablation. Median follow-up duration was 389 days (interquartile range 219-599). Mean age was 59 years (71% male); 136 patients underwent cryoballoon and 133 patients underwent radiofrequency ablation. Acute electrical PVI was 100% for both techniques. Procedure duration was significantly shorter in cryoballoon vs radiofrequency (166.5 vs 184.13 min P = 0.016). Complication rates were similar (6.0 vs 6.7%, P = 1.00). Single procedure freedom of atrial arrhythmias was significantly higher in cryoballoon as compared to radiofrequency (75.2 vs 57.4%, P = 0.013). In multivariate analysis, persistent AF, AF duration, and cryoballoon ablation were associated with freedom of atrial tachyarrhythmias. The number of repeat ablation procedures was significantly lower in the cryoballoon compared to radiofrequency (15.0 vs 24.3%, P = 0.045). At repeat ablation, pulmonary vein reconnection rate was significantly lower after cryoballoon as compared to radiofrequency ablation (36.8 vs 58.1%, P = 0.003). Improved arrhythmia-free survival and more durable pulmonary vein isolation is seen after PVI using second-generation cryoballoon as compared to contact-force radiofrequency, in patients with drug-refractory paroxysmal AF. Complication rates for both ablation techniques are low.

A prospective clinical study to evaluate the safety and performance of wireless localization of nonpalpable breast lesions using radiofrequency identification technology.

Science.gov (United States)

Dauphine, Christine; Reicher, Joshua J; Reicher, Murray A; Gondusky, Christina; Khalkhali, Iraj; Kim, Michelle

2015-06-01

The purpose of this study was to evaluate the safety and performance of localizing nonpalpable breast lesions using radiofrequency identification technology. Twenty consecutive women requiring preoperative localization of a breast lesion were recruited. Subjects underwent placement of both a hook wire and a radiofrequency identification tag immediately before surgery. The radiofrequency identification tag was the primary method used by the operating surgeon to localize each lesion during excision, with the hook wire serving as backup in case of tag migration or failed localization. Successful localization with removal of the intended lesion was the primary outcome measured. Tag migration and postoperative infection were also noted to assess safety. Twenty patients underwent placement of a radiofrequency identification tag, 12 under ultrasound guidance and eight with stereotactic guidance. In all cases, the radiofrequency identification tag was successfully localized by the reader at the level of the skin before incision, and the intended lesion was removed along with the radiofrequency identification tag. There were no localization failures and no postoperative infections. Tag migration did not occur before incision, but in three cases, occurred as the lesion was being retracted with fingers to make the final cut along the deep surface of the specimen. In this initial clinical study, radiofrequency tags were safe and able to successfully localize nonpalpable breast lesions. Radiofrequency identification technology may represent an alternative method to hook wire localization.

Effect of Mobile Phone Radiofrequency Electromagnetic Fields on ...

African Journals Online (AJOL)

Summary: Since cell phones emit radiofrequency electromagnetic fields (EMFs), this study tested the hypothesis that cell phones placed near the heart may interfere with the electrical rhythm of the heart or affect the blood pressure. Following informed consent, eighteen randomly selected apparently healthy male volunteers ...

Radiofrequency power deposition during magnetic resonance diagnostic examinations

International Nuclear Information System (INIS)

Grandolfo, M.; Vecchia, P.

1988-01-01

Magnetic Resonance Imaging and Spectroscopy (MRI, MRS) require that subjects be exposed to radiofrequency field, and the corresponding energy absorption leads to tissue heating. The main question, thus, to be considered in connection to safety and health aspects is related to the specific absorption rate (SAR) in the imaged subject and the exposure durations which might put a practical limit on the pulse sequence which can be used. In this paper some models and experimental results for radiofrequency power deposition in MRI and MRS machines are reviewed. Models show that energy dissipation is a function of the frequency, RF incident power density, exposure duration, coupling between the RF coil and the subject, and several properties of the exposed tissue, including conductivity, dielectric constant, specific gravity, size, and orientation relative to the field polarization. The ability of the body's normal thermoregulatory responses to cope with high levels of RF energy deposition must be also taken into account

Process for selected gas oxide removal by radiofrequency catalysts

Science.gov (United States)

Cha, Chang Y.

1993-01-01

This process to remove gas oxides from flue gas utilizes adsorption on a char bed subsequently followed by radiofrequency catalysis enhancing such removal through selected reactions. Common gas oxides include SO.sub.2 and NO.sub.x.

Radiofrequency in cosmetic dermatology.

Science.gov (United States)

Beasley, Karen L; Weiss, Robert A

2014-01-01

The demand for noninvasive methods of facial and body rejuvenation has experienced exponential growth over the last decade. There is a particular interest in safe and effective ways to decrease skin laxity and smooth irregular body contours and texture without downtime. These noninvasive treatments are being sought after because less time for recovery means less time lost from work and social endeavors. Radiofrequency (RF) treatments are traditionally titrated to be nonablative and are optimal for those wishing to avoid recovery time. Not only is there minimal recovery but also a high level of safety with aesthetic RF treatments. Copyright © 2014 Elsevier Inc. All rights reserved.

Prospective, pilot evaluation of the performance of nanofractional radiofrequency for improvement of skin texture via skin resurfacing.

Science.gov (United States)

Bohnert, Krista; Dorizas, Andrew; Sadick, Neil

2018-02-01

The latest generation of radiofrequency, nanofractional radiofrequency, allows the heat energy to be delivered through the use of pins or needles as electrodes, facilitating increased efficacy and reduced pain, downtime, and side effects. The objective of this prospective pilot clinical study was to evaluate the efficacy of nanofractional radiofrequency in skin resurfacing. Seventeen subjects were enrolled in the study, and each received three nanofractional radiofrequency (160-pin tip) treatments in the facial area at 3-week intervals. Follow-up visits were scheduled at 1 and 2 months after the final treatment. Clinical photography, patient, and investigator assessments were conducted during the treatment visits and follow-up. All subjects completed the study. At the 1- and 2-month follow-up, there was a moderate to significant improvement (2.6 and 3.5, respectively, P = .01) according to the investigator global esthetic improvement scale rating. Most subjects reported that they were satisfied or very satisfied with the outcome and level of comfort. Nanofractional radiofrequency is a safe and effective strategy for improving texture, tone, and skin laxity with high patient satisfaction and tolerable safety profile. © 2017 Wiley Periodicals, Inc.

Adaptive Response in Animals Exposed to Non-Ionizing Radiofrequency Fields: Some Underlying Mechanisms

Directory of Open Access Journals (Sweden)

Yi Cao

2014-04-01

Full Text Available During the last few years, our research group has been investigating the phenomenon of adaptive response in animals exposed to non-ionizing radiofrequency fields. The results from several separate studies indicated a significant increase in survival, decreases in genetic damage as well as oxidative damage and, alterations in several cellular processes in mice pre-exposed to radiofrequency fields and subsequently subjected to sub-lethal or lethal doses of γ-radiation or injected with bleomycin, a radiomimetic chemical mutagen. These observations indicated the induction of adaptive response providing the animals the ability to resist subsequent damage. Similar studies conducted by independent researchers in mice and rats have supported our observation on increased survival. In this paper, we have presented a brief review of all of our own and other independent investigations on radiofrequency fields-induced adaptive response and some underlying mechanisms discussed.

Percutaneous treatment of hepatocellular carcinoma in patients with cirrhosis: A comparison of the safety of cryoablation and radiofrequency ablation

International Nuclear Information System (INIS)

Dunne, Ruth M.; Shyn, Paul B.; Sung, Jeffrey C.; Tatli, Servet; Morrison, Paul R.; Catalano, Paul J.; Silverman, Stuart G.

2014-01-01

Purpose: To compare the safety of image-guided percutaneous cryoablation and radiofrequency ablation in the treatment of hepatocellular carcinoma in patients with cirrhosis. Materials and methods: This retrospective HIPAA-compliant study received institutional review board approval. Forty-two adult patients with cirrhosis underwent image-guided percutaneous ablation of hepatocellular carcinoma from 2003 to 2011. Twenty-five patients underwent 33 cryoablation procedures to treat 39 tumors, and 22 underwent 30 radiofrequency ablation procedures to treat 39 tumors. Five patients underwent both cryoablation and radiofrequency ablation procedures. Complication rates and severity per procedure were compared between the ablation groups. Potential confounding patient, procedure, and tumor-related variables were also compared. Statistical analyses included Kruskal–Wallis, Wilcoxon rank sum, and Fisher's exact tests. Two-sided P-values <0.05 were considered significant. Results: The overall complication rates, 13 (39.4%) of 33 cryoablation procedures versus eight (26.7%) of 30 radiofrequency ablation procedures and severe/fatal complication rates, two (6.1%) of 33 cryoablation procedures versus one (3.3%) of 30 radiofrequency ablation procedures, were not significantly different between the ablation groups (both P = 0.26). Severe complications included pneumothoraces requiring chest tube insertion during two cryoablation procedures. One death occurred within 90 days of a radiofrequency ablation procedure; all other complications were managed successfully. Conclusion: No significant difference was seen in the overall safety of image-guided percutaneous cryoablation and radiofrequency ablation in the treatment of hepatocellular carcinoma in patients with cirrhosis

The inflammatory marker suPAR after cardiac arrest

DEFF Research Database (Denmark)

Rundgren, Malin; Lyngbaek, Stig; Fisker, Helle

2015-01-01

. This pilot study aimed at investigating suPAR levels in relation to outcome after CA and mild induced hypothermia. METHODS: suPAR levels were measured at 6, 36, and 72 hours in patients treated with hypothermia after CA. suPAR levels were analyzed in relation to survival after 6 months. Receiver operating...

Treatment of Osteoid Osteomas Using a Navigational Bipolar Radiofrequency Ablation System

Energy Technology Data Exchange (ETDEWEB)

Wallace, Adam N., E-mail: wallacea@mir.wustl.edu; Tomasian, Anderanik, E-mail: tomasiana@mir.wustl.edu [Washington University School of Medicine, Mallinckrodt Institute of Radiology (United States); Chang, Randy O., E-mail: changr@wusm.wustl.edu [Washington University School of Medicine (United States); Jennings, Jack W., E-mail: jenningsj@mir.wustl.edu [Washington University School of Medicine, Mallinckrodt Institute of Radiology (United States)

2016-05-15

BackgroundPercutaneous CT-guided radiofrequency ablation is a safe and effective minimally invasive treatment for osteoid osteomas. This technical case series describes the use of a recently introduced ablation system with a probe that can be curved in multiple directions, embedded thermocouples for real-time monitoring of the ablation volume, and a bipolar design that obviates the need for a grounding pad.MethodsMedical records of all patients who underwent radiofrequency ablation of an osteoid osteoma with the STAR Tumor Ablation System (DFINE; San Jose, CA) were reviewed. The location of each osteoid osteoma, nidus volume, and procedural details were recorded. Treatment efficacy and long-term complications were assessed at clinical follow-up.ResultsDuring the study period, 18 osteoid osteomas were radiofrequency ablated with the multidirectional bipolar system. Lesion locations included the femur (50 %; 9/18), tibia (22 %; 4/18), cervical spine (11 %; 2/18), calcaneus (5.5 %; 1/18), iliac bone (5.5 %; 1/18), and fibula (5.5 %; 1/18). The median nidus volume of these cases was 0.33 mL (range 0.12–2.0 mL). All tumors were accessed via a single osseous channel. Median cumulative ablation time was 5 min and 0 s (range 1 min and 32 s–8 min and 50 s). All patients with clinical follow-up reported complete symptom resolution. No complications occurred.ConclusionSafe and effective CT-guided radiofrequency ablation of osteoid osteomas can be performed in a variety of locations using a multidirectional bipolar system.

Treatment of Osteoid Osteomas Using a Navigational Bipolar Radiofrequency Ablation System

International Nuclear Information System (INIS)

Wallace, Adam N.; Tomasian, Anderanik; Chang, Randy O.; Jennings, Jack W.

2016-01-01

BackgroundPercutaneous CT-guided radiofrequency ablation is a safe and effective minimally invasive treatment for osteoid osteomas. This technical case series describes the use of a recently introduced ablation system with a probe that can be curved in multiple directions, embedded thermocouples for real-time monitoring of the ablation volume, and a bipolar design that obviates the need for a grounding pad.MethodsMedical records of all patients who underwent radiofrequency ablation of an osteoid osteoma with the STAR Tumor Ablation System (DFINE; San Jose, CA) were reviewed. The location of each osteoid osteoma, nidus volume, and procedural details were recorded. Treatment efficacy and long-term complications were assessed at clinical follow-up.ResultsDuring the study period, 18 osteoid osteomas were radiofrequency ablated with the multidirectional bipolar system. Lesion locations included the femur (50 %; 9/18), tibia (22 %; 4/18), cervical spine (11 %; 2/18), calcaneus (5.5 %; 1/18), iliac bone (5.5 %; 1/18), and fibula (5.5 %; 1/18). The median nidus volume of these cases was 0.33 mL (range 0.12–2.0 mL). All tumors were accessed via a single osseous channel. Median cumulative ablation time was 5 min and 0 s (range 1 min and 32 s–8 min and 50 s). All patients with clinical follow-up reported complete symptom resolution. No complications occurred.ConclusionSafe and effective CT-guided radiofrequency ablation of osteoid osteomas can be performed in a variety of locations using a multidirectional bipolar system.

Pulmonary venous thrombosis secondary to radiofrequency ablation of the pulmonary veins.

Science.gov (United States)

López-Reyes, Raquel; García-Ortega, Alberto; Torrents, Ana; Feced, Laura; Calvillo, Pilar; Libreros-Niño, Eugenia Alejandra; Escrivá-Peiró, Juan; Nauffal, Dolores

2018-01-01

Pulmonary Vein Thrombosis (PVT) is a rare and underdiagnosed entity produced by local mechanical nature mechanisms, vascular torsion or direct injury to the vein. PVT has been described in clinical cases or small multicenter series mainly in relation to pulmonary vein stenosis, metastatic carcinoma, fibrosing mediastinitis, as an early surgical complication of lung transplantation lobectomy and radiofrequency ablation performed in patients with atrial fibrillation, although in some cases the cause is not known. We report the case of a 57 years old male with history of atrial fibrillation treated by radiofrequency ablation who was admitted in our center because of a two-week history of consistent pleuritic pain in the left hemithorax and low-grade hemoptysis and a lung consolidation treated as a pneumonia with antibiotic but not responding to medical therapy. In view of the poor evolution of the patient, computed tomography angiography was performed with findings of PVT and secondary venous infarction and anticoagulation therapy was optimized. At the end, pulmonary resection was performed due to hemorrhagic recurrence. PVT remains a rare complication of radiofrequency ablation and other procedures involving pulmonary veins. Clinical suspicion and early diagnosis is crucial because is a potentially life-threatening entity.

Indication of the radiofrequency induced lesion size by pre-ablation measurements

DEFF Research Database (Denmark)

Stagegaard, Niels; Petersen, Helen Høgh; Chen, Xu

2005-01-01

BACKGROUND: During radiofrequency ablation of arrhythmias tissue heating and hence lesion size depend on electrode-tissue contact and cooling of the electrode tip caused by cavitary blood flow. These factors are unique and unknown for each catheter placement in the beating heart. A tool for asses......BACKGROUND: During radiofrequency ablation of arrhythmias tissue heating and hence lesion size depend on electrode-tissue contact and cooling of the electrode tip caused by cavitary blood flow. These factors are unique and unknown for each catheter placement in the beating heart. A tool...... for assessing these factors prior to ablation may indicate the lesion size which will be obtained for any given catheter position. METHODS AND RESULTS: Radiofrequency ablation was performed in vitro on strips of left ventricular porcine myocardium during two different levels of convective cooling (0 or 0.1 m....../s), two different contact pressures (10 or 30 g) and parallel or perpendicular electrode-tissue orientation using 7F 4 mm tip catheters. Prior to ablation the impedance rise (DeltaIMP) caused by the obtained contact and the temperature rise with a 0.6 W 5 s test pulse (DeltaT) were measured. Subsequently...

Combined kinetic and transport modeling of radiofrequency current drive

International Nuclear Information System (INIS)

Dumont, R.; Giruzzi, G.; Barbato, E.

2000-07-01

A numerical model for predictive simulations of radiofrequency current drive in magnetically confined plasmas is developed. It includes the minimum requirements for a self consistent description of such regimes, i.e., a 3-D ,kinetic equation for the electron distribution function, 1-D heat and current transport equations, and resonant coupling between velocity space and configuration space dynamics, through suitable wave propagation equations. The model finds its full application in predictive studies of complex current profile control scenarios in tokamaks, aiming at the establishment of internal transport barriers by the simultaneous use of various radiofrequency current drive methods. The basic properties of this non-linear numerical system are investigated and illustrated by simulations applied to reversed magnetic shear regimes obtained by Lower Hybrid and Electron Cyclotron current drive for parameters typical of the Tore Supra tokamak. (authors)

The Precautionary Principle in the Context of Mobile Phone and Base Station Radiofrequency Exposures

OpenAIRE

Dolan, Mike; Rowley, Jack

2009-01-01

Background No health hazard has been established from exposure to radiofrequency fields up to the levels recommended by the International Commission on Non-Ionizing Radiation Protection. However, in response to public concern and the perceived level of scientific uncertainty, there are continuing calls for the application of the precautionary principle to radiofrequency exposures from mobile phones and base stations. Objective We examined the international evolution of calls for precautionary...

It's quicker "Par Avignon"!

CERN Multimedia

2005-01-01

For a few years, the CERN Library has been receiving books from the University of Hanover sent via Avignon, at least that's what it says on the envelope. Such a detour would mean that parcels were travelling 720 km more than the distance separating Geneva and Hanover, which would be a very strange state of affairs. The explanation lies in a spelling mistake. The sender has been stamping parcels with a stamp that says "Par Avignon prioritaire" (first-class via Avignon) instead of "Par Avion prioritaire" (First Class Air Mail), a source of much amusement to the librarians!

Serum suPAR in patients with FSGS: trash or treasure?

Science.gov (United States)

Maas, Rutger J H; Deegens, Jeroen K J; Wetzels, Jack F M

2013-07-01

The urokinase-type plasminogen activator receptor (uPAR) has important functions in cell migration. uPAR can be shed from the cell membrane resulting in soluble uPAR (suPAR). Further cleavage gives rise to shorter fragments with largely unknown functions. Recent studies have demonstrated that both overexpression of uPAR on podocytes and the administration of suPAR cause proteinuria in mice. The common pathogenic mechanism involves the activation of podocyte β3-integrin. Increased activation of β3-integrin is also observed in patients with focal and segmental glomerulosclerosis (FSGS). These observations form the basis for the hypothesis that suPAR may be the circulating factor causing FSGS. A recent study fosters this idea by demonstrating increased suPAR levels in the serum of patients with FSGS and reporting an association with recurrence after transplantation and response to plasmapheresis. However, this study was heavily biased, and subsequent studies have given conflicting results. Although the experimental work is very suggestive, at present there is no proof that any known human suPAR fragment causes FSGS in humans. We therefore suggest that the measurement of suPAR using currently available assays has absolutely no value at the present time in decision-making in routine clinical practice.

Proteinase-Activated Receptor 1 (PAR1 regulates leukemic stem cell functions.

Directory of Open Access Journals (Sweden)

Nicole Bäumer

Full Text Available External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1-/- hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1-/- leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance.

Proteinase-Activated Receptor 1 (PAR1) regulates leukemic stem cell functions.

Science.gov (United States)

Bäumer, Nicole; Krause, Annika; Köhler, Gabriele; Lettermann, Stephanie; Evers, Georg; Hascher, Antje; Bäumer, Sebastian; Berdel, Wolfgang E; Müller-Tidow, Carsten; Tickenbrock, Lara

2014-01-01

External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1-/- hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1-/- leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance.

Noninvasive in vivo oximetric imaging by radiofrequency FT EPR

NARCIS (Netherlands)

Subramanian, S; Yamada, K; Irie, A; Murugesan, R; Cook, JA; Devasahayam, N; Van Dam, GM; Mitchell, JB; Krishna, MC

A novel method, called relaxo-oximetry, for rapid spatially resolved in vivo measurements of oxygen concentration using time-domain radiofrequency (RF) electron paramagnetic resonance (EPR) is described. Time-domain data from triaryl methyl (TAM)-based single-electron contrast agents were processed

Serum suPAR in patients with FSGS: trash or treasure?

NARCIS (Netherlands)

Maas, R.J.H.; Deegens, J.K.J.; Wetzels, J.F.M.

2013-01-01

The urokinase-type plasminogen activator receptor (uPAR) has important functions in cell migration. uPAR can be shed from the cell membrane resulting in soluble uPAR (suPAR). Further cleavage gives rise to shorter fragments with largely unknown functions. Recent studies have demonstrated that both

Benign thyroid nodule unresponsive to radiofrequency ablation treated with laser ablation: a case report.

Science.gov (United States)

Oddo, Silvia; Balestra, Margherita; Vera, Lara; Giusti, Massimo

2018-05-11

Radiofrequency ablation and laser ablation are safe and effective techniques for reducing thyroid nodule volume, neck symptoms, and cosmetic complaints. Therapeutic success is defined as a nodule reduction > 50% between 6 and 12 months after the procedure, but a percentage of nodules inexplicably do not respond to thermal ablation. We describe the case of a young Caucasian woman with a solid benign thyroid nodule who refused surgery and who had undergone radiofrequency ablation in 2013. The nodule did not respond in terms of either volume reduction or improvement in neck symptoms. After 2 years, given the patient's continued refusal of thyroidectomy, we proposed laser ablation. The nodule displayed a significant volume reduction (- 50% from radiofrequency ablation baseline volume, - 57% from laser ablation baseline), and the patient reported a significant improvement in neck symptoms (from 6/10 to 1/10 on a visual analogue scale). We conjecture that some benign thyroid nodules may be intrinsically resistant to necrosis when one specific ablation technique is used, but may respond to another technique. To the best of our knowledge, this is the first description of the effect of performing a different percutaneous ablation technique in a nodule that does not respond to radiofrequency ablation.

Radiofrequency assisted pancreaticoduodenectomy for palliative surgical resection of locally advanced pancreatic adenocarcinoma.

Science.gov (United States)

Kumar, Jayant; Reccia, Isabella; Sodergren, Mikael H; Kusano, Tomokazu; Zanellato, Artur; Pai, Madhava; Spalding, Duncan; Zacharoulis, Dimitris; Habib, Nagy

2018-03-20

Despite careful patient selection and preoperative investigations curative resection rate (R0) in pancreaticoduodenectomy ranges from 15% to 87%. Here we describe a new palliative approach for pancreaticoduodenectomy using a radiofrequency energy device to ablate tumor in situ in patients undergoing R1/R2 resections for locally advanced pancreatic ductal adenocarcinoma where vascular reconstruction was not feasible. There was neither postoperative mortality nor significant morbidity. Each time the ablation lasted less than 15 minutes. Following radiofrequency ablation it was observed that the tumor remnant attached to the vessel had shrunk significantly. In four patients this allowed easier separation and dissection of the ablated tumor from the adherent vessel leading to R1 resection. In the other two patients, the ablated tumor did not separate from vessel due to true tumor invasion and patients had an R2 resection. The ablated remnant part of the tumor was left in situ. Whenever pancreaticoduodenectomy with R0 resection cannot be achieved, this new palliative procedure could be considered in order to facilitate resection and enable maximum destruction in remnant tumors. Six patients with suspected tumor infiltration and where vascular reconstruction was not warranted underwent radiofrequency-assisted pancreaticoduodenectomy for locally advanced pancreatic ductal adenocarcinoma. Radiofrequency was applied across the tumor vertically 5-10 mm from the edge of the mesenteric and portal veins. Following ablation, the duodenum and the head of pancreas were removed after knife excision along the ablated line. The remaining ablated tissue was left in situ attached to the vessel.

Radiofrequency and health. Expertise update. Opinion of the ANSES. Collective expertise report

International Nuclear Information System (INIS)

Cardis, Elisabeth; Dore, Jean-Francois; Marc-Vergnes, Jean-Pierre; Agnani, Jean-Benoit; Bruguiere, Pierre; Crouzier, David; Debaz, Josquin; Debuire, Brigitte; Deltour, Isabelle; LE Drean, Yves; Ledoigt, Gerard; Letertre, Thierry; Marchand, Dorothee; Massardier-Pilonchery, Amelie; Nadi, Mustapha; Pereira De Vasconcelos, Anne; Hours, Martine; Fite, Johanna; Merckel, Olivier; Roth, Olivia; Vergriette, Benoit; Saddoki, Sophia

2013-10-01

In a context of development of new technologies of wireless communications, and therefore of radio-electric signals used to transmit information, this voluminous document reports a detailed study on the effects of radiofrequency on health. It is notably based on a large literature survey and on an assessment of the level of proof of these effects by experts (proved, possible, probable, insufficiently proved, or no effect on mankind). These effects can be either biological or on health. The report presents the context, scope and modalities of the expertise study, presents the main artificial and natural sources of radiofrequency radiation, gives a detailed presentation of new exposure sources (new signals, new radio-electric networks and their applications like mobile phones, pads, mobile television, local wireless networks, RFID, so on). It describes metrology and dose measurement techniques for electromagnetic fields (exposure characterization in laboratory, characterization of the electromagnetic environment, individual exposure measurement devices, digital dosimetry). It addresses the efficiency of anti-wave devices. The next part presents the literature survey (method, analysis, results). The authors then report an assessment of the risk level related to radio-frequencies for the central nervous system (neurotoxicity mechanisms, cognitive functions, memory and behaviour, sleep and circadian rhythms, hearing functions, neurological and neuro-degenerative diseases), and an assessment of the risk level of radio-frequencies for other non-carcinogenic effects (possible mechanisms, reproduction, immunology, endocrine system, and so on). They discuss the researches on potential carcinogenic mechanisms. They give an overview of the evolutions of regulations and management measures in France, and propose a set of recommendations

Accouchement par forceps: indications et pronostic materno-foetal ...

African Journals Online (AJOL)

L'accouchement par voie basse, peut être parfois compromis par des facteurs maternels, foetaux ou materno-foetaux nécessitant des moyens thérapeutiques comme le forceps pour achever l'accouchement par voie naturelle. Le forceps, une méthode qui n'est pas sans risque pour la mère et le nouveau-né. Nous avons ...

A sheath model for arbitrary radiofrequency waveforms

Science.gov (United States)

Turner, M. M.; Chabert, Pascal

2012-10-01

The sheath is often the most important region of a rf plasma, because discharge impedance, power absorption and ion acceleration are critically affected by the behaviour of the sheath. Consequently, models of the sheath are central to any understanding of the physics of rf plasmas. Lieberman has supplied an analytical model for a radio-frequency sheath driven by a single frequency, but in recent years interest has been increasing in radio-frequency discharges excited by increasingly complex wave forms. There has been limited success in generalizing the Lieberman model in this direction, because of mathematical complexities. So there is essentially no sheath model available to describe many modern experiments. In this paper we present a new analytical sheath model, based on a simpler mathematical framework than that of Lieberman. For the single frequency case, this model yields scaling laws that are identical in form to those of Lieberman, differing only by numerical coefficients close to one. However, the new model may be straightforwardly solved for arbitrary current waveforms, and may be used to derive scaling laws for such complex waveforms. In this paper, we will describe the model and present some illustrative examples.

Explanation for Cancer in Rats, Mice and Humans due to Cell Phone Radiofrequency Radiation

OpenAIRE

Feldman, Bernard J.

2016-01-01

Very recently, the National Toxicology Program reported a correlation between exposure to whole body 900 MHz radiofrequency radiation and cancer in the brains and hearts of Sprague Dawley male rats. This paper proposes the following explanation for these results. The neurons around the rat's brain and heart form closed electrical circuits and, following Faraday's Law, 900 MHz radiofrequency radiation induces 900 MHz electrical currents in these neural circuits. In turn, these 900 MHz currents...

Percutaneous osteoid osteoma treatment with combination of radiofrequency and alcohol ablation

Energy Technology Data Exchange (ETDEWEB)

Akhlaghpoor, S. [Noor Medical Imaging Center, Tehran (Iran, Islamic Republic of)]. E-mail: akhlaghpoor@nmri-ir.com; Tomasian, A. [Noor Medical Imaging Center, Tehran (Iran, Islamic Republic of); Arjmand Shabestari, A. [Noor Medical Imaging Center, Tehran (Iran, Islamic Republic of); Ebrahimi, M. [Noor Medical Imaging Center, Tehran (Iran, Islamic Republic of); Alinaghizadeh, M.R. [Noor Medical Imaging Center, Tehran (Iran, Islamic Republic of)

2007-03-15

Aim: To assess the efficacy of percutaneous osteoid osteoma treatment using a combination of radiofrequency ablation (RFA) and alcohol ablation with regard to technical and long-term clinical success. Materials and methods: From December 2001 to November 2004, RFA and subsequent alcohol ablation was performed on 54 patients with osteoid osteoma, diagnosed clinically using radiography, computed tomography (CT) and symptoms. Under general anaesthesia, treatment was performed via percutaneous access under thin section (2 mm) spiral CT guidance in all cases with an 11 G radiofrequency-compatible coaxial needle and 2 mm coaxial drill system and 1.0 cm active tip 17 G non-cooled radiofrequency needle. RFA was performed at 90 {sup o}C for a period of 6 min. After needle removal, 0.5-1.0 ml absolute alcohol (99.8% concentration) was injected directly into the nidus using a 20 G needle. Patients were discharged within 24 h and followed up clinically (at 1 week, 1 month and every 3 months thereafter). Results: The technical success rate was 100%. Complications occurred in two patients consisting of local mild cellulitis in entry site and peripheral small zone paresthesia on the anterior part of leg. The follow-up period range was 13-48 months (mean {+-} SD, 28.2 {+-} 7.4 months). Prompt pain relief and return to normal activities were observed in 52 of 54 patients. Recurrent pain occurred in two patients after a 1 and 3 months period of being pain free, respectively; a second RFA and alcohol ablation was performed achieving successful results. Primary and secondary clinical success rates were 96.3% (52/54 patients) and 100% (2/2 patients), respectively. Conclusion: Percutaneous osteoid osteoma treatment with combination of radiofrequency and alcohol ablation is safe, effective and minimally invasive with high primary and secondary success rates. Persistent or recurrent lesions can be effectively re-treated.

Percutaneous osteoid osteoma treatment with combination of radiofrequency and alcohol ablation

International Nuclear Information System (INIS)

Akhlaghpoor, S.; Tomasian, A.; Arjmand Shabestari, A.; Ebrahimi, M.; Alinaghizadeh, M.R.

2007-01-01

Aim: To assess the efficacy of percutaneous osteoid osteoma treatment using a combination of radiofrequency ablation (RFA) and alcohol ablation with regard to technical and long-term clinical success. Materials and methods: From December 2001 to November 2004, RFA and subsequent alcohol ablation was performed on 54 patients with osteoid osteoma, diagnosed clinically using radiography, computed tomography (CT) and symptoms. Under general anaesthesia, treatment was performed via percutaneous access under thin section (2 mm) spiral CT guidance in all cases with an 11 G radiofrequency-compatible coaxial needle and 2 mm coaxial drill system and 1.0 cm active tip 17 G non-cooled radiofrequency needle. RFA was performed at 90 o C for a period of 6 min. After needle removal, 0.5-1.0 ml absolute alcohol (99.8% concentration) was injected directly into the nidus using a 20 G needle. Patients were discharged within 24 h and followed up clinically (at 1 week, 1 month and every 3 months thereafter). Results: The technical success rate was 100%. Complications occurred in two patients consisting of local mild cellulitis in entry site and peripheral small zone paresthesia on the anterior part of leg. The follow-up period range was 13-48 months (mean ± SD, 28.2 ± 7.4 months). Prompt pain relief and return to normal activities were observed in 52 of 54 patients. Recurrent pain occurred in two patients after a 1 and 3 months period of being pain free, respectively; a second RFA and alcohol ablation was performed achieving successful results. Primary and secondary clinical success rates were 96.3% (52/54 patients) and 100% (2/2 patients), respectively. Conclusion: Percutaneous osteoid osteoma treatment with combination of radiofrequency and alcohol ablation is safe, effective and minimally invasive with high primary and secondary success rates. Persistent or recurrent lesions can be effectively re-treated

A study of the fluorescence of the rare gases excited by nuclear particles. Use of the principle for the detection of nuclear radiation by scintillation; Etude de la fluorescence des gaz rares excites par des particules nucleaires. Utilisation pour la detection des rayonnements nucleaires par scintillation

Energy Technology Data Exchange (ETDEWEB)

Koch, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1959-12-15

In the first part is studied the properties of atoms excited by the passage of {alpha} particles through the various rare gases at atmospheric pressure. A spectral analysis of the emitted light showed that certain impurities play an important part in producing the fluorescence, and it has led to the conclusion that the light emission contains at least two components - one very short - lived due to the direct deexcitation of the rare gas, the other relatively slower due to the energy transfers to the impurity. The measurement of the life-time of the excited states has confirmed this foregoing hypothesis, the rapid part of the impulse is extremely short: less than 2,25.10{sup -9} s in the case of xenon; the slower part has a life-time depending directly on the nitrogen concentration, nitrogen being the impurity giving the largest effect in all cases. The study of rare gases under the influence of an electric field has made it possible to show that the amount of light produced by an {alpha} particle can be multiplied (by 60, for example, in a field of 600 V:cm) so that the luminescent efficiency is greater than in the case of INaTI. In the second part the characteristics of the rare gases acting as scintillators is examined, the most important property being the absence of fluorescence saturation when the intensity of the excitation incident on the gas is very large. This, together with the very short time of scintillation has made it possible to study a certain number of nuclear physical applications (heavy particle energy-measurements, kinetic studies on nuclear reactors, neutron spectroscopy). (author) [French] On etudie dans la premiere partie les proprietes des atomes excites par le passage de particules {alpha} dans les differents gaz rares a la pression atmospherique. L'etude spectrale de la lumiere emise a montre que certaines impuretes jouent un role considerable dans la fluorescence et on a ete amene a penser que l'emission de lumiere comporte au moins deux

Issues in epidemiological studies of radiofrequency workers

International Nuclear Information System (INIS)

Hocking, B.

1985-01-01

The paper reviews some of the issues in a proposed epidemiological study of radiofrequency workers. First a few other epidemiological studies are discussed to illustrate some of the common problems such as inadequate definition of effects and/or exposure. Then technical problems in determining dosage and responses as well as study design are reviewed, and finally the administrative aspects of ethics, industrial relations and costs are considered

ROLE OF RADIOFREQUENCY ABLATION IN ADENOMA SEBACEUM

Directory of Open Access Journals (Sweden)

Ch. Madh

2016-03-01

Full Text Available Adenoma sebaceum, pathognomonic of tuberous sclerosis, are tiny angiofibromas which commonly occur over central part of face. Recurrence after treatment is common and hence a need for inexpensive, safe and efficient treatment is required. Radiofrequency ablation is a safe and an economical procedure and has been known to cause less scarring with good aesthetic results compared to other ablative methods such as electrocautery.

Radiofrequency sensory ablation as a treatment for symptomatic unilateral lumbosacral junction pseudarticulation (Bertolotti's syndrome): a case report.

Science.gov (United States)

Burnham, Robert

2010-06-01

Describe the clinical presentation, diagnostic evaluation, and successful treatment of a case of symptomatic unilateral lumbosacral junction pseudarticulation using a novel radiofrequency nerve ablation technique. A 56-year-old female patient who had suffered with low back and right upper buttock pain for 16 years experienced incomplete relief with L4/5 facet joint radiofrequency ablation. She was found to have an elongated right L5 transverse process that articulated with the sacral ala (Bertolotti's syndrome). Fluoroscopically guided local anesthetic/corticosteroid injection into the pseudarthrosis eliminated her residual right buttock pain for the duration of the local anesthetic only. Complete pain relief was achieved by injecting local anesthetic circumferentially around the posterior pseudarthrosis articular margin. Accordingly, bipolar radiofrequency strip thermal lesions were created at the same locations. Complete pain relief and full restoration of function was achieved for 16 months postprocedure. This case report describes a novel radiofrequency technique for treating symptomatic lumbosacral junction pseudarticulation that warrants further evaluation.

Comparison of Voice Quality Between Patients Who Underwent Inferior Turbinoplasty or Radiofrequency Cauterization.

Science.gov (United States)

Göker, Ayşe Enise; Aydoğdu, İmran; Saltürk, Ziya; Berkiten, Güler; Atar, Yavuz; Kumral, Tolgar Lütfi; Uyar, Yavuz

2017-01-01

The aim of this study was to analyze and compare the vocal quality in patients who underwent either submucosal turbinectomy or radiofrequency cauterization. In this study, we enrolled 60 patients diagnosed with inferior concha hypertrophy. These patients were divided into two groups by using computer program "Research Randomizer." Of the 60 patients, 30 underwent submucosal inferior turbinoplasty and 30 underwent radiofrequency cauterization. The control group was composed of 30 healthy adults with no nasal or upper aerodigestive system pathology. The patients were checked at weeks 1, 2, and 4. Voice records were taken before the procedure and at week 4 postprocedure. The mean age of patients in the inferior turbinoplasty group was 29.4 years (range: 19-42 years); in the radiofrequency group, it was 30.30 years (range: 18-50 years). There was no statistical difference in age between groups. In the inferior turbinoplasty group, there were 16 male and 14 female patients, and in the radiofrequency group, there were 13 male and 17 female patients. There was no significant difference in the number of males and females between groups. Voice professionals, especially singers, actors, and actresses, should be informed about possible voice changes before undergoing endonasal surgery because these individuals are more sensitive to changes in resonance organs. We believe that voice quality should be regarded as a highly important parameter when measuring the success of endonasal surgery. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Investigation of beech wood modified by radio-frequency discharge plasma

Czech Academy of Sciences Publication Activity Database

Novák, I.; Popelka, A.; Špitalský, Z.; Mičušík, M.; Omastová, M.; Valentin, M.; Sedliačik, J.; Janigová, I.; Kleinová, A.; Šlouf, Miroslav

2015-01-01

Roč. 119, September (2015), s. 88-94 ISSN 0042-207X Institutional support: RVO:61389013 Keywords : radio-frequency plasma * beech wood * adhesive properties Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.558, year: 2015

Radiofrequency neurolysis in a clinical model. Neuropathological correlation

International Nuclear Information System (INIS)

Smith, H.P.; McWhorter, J.M.; Challa, V.R.

1981-01-01

Reports differ on which nerve fibers are affected by radiofrequency lesions made in peripheral nerves, some stating that primarily the myelinated delta and unmyelinated C fibers are destroyed, others stating that the destruction affects all sizes of nerve fibers and both myelinated and unmyelinated fibers. This study was designed to confirm one of those two findings, and to study the role that different temperatures might play in determining which fibers are affected. Radiofrequency lesions (85 degrees C for 2 minutes) were made in dogs by placing a temperature-monitored electrode into the lumber intervertebral foramina. The dogs were killed at intervals up to 6 weeks after rhizotomy, and the lesions were studied by light and electron microscopy. In all lesions, there was a total loss of unmyelinated fibers and a nearly total loss of myelinated fibers. In other dogs, 2-minute lesions were made at 45 degrees, 55 degrees, 65 degrees, and 75 degrees C, and the lesions examined 1 week later. Again, all sizes and all types of fibers were destroyed

Pulsed radiofrequency microwave fields around a quadrupole particle accelerator: measurement and safety evaluation

International Nuclear Information System (INIS)

Sachdev, R.N.; Swarup, G.; Rajan, K.K.; Joseph, L.

1996-01-01

Pulsed radiofrequency microwave radiation (RFMR) fields occur during the use of high power microwaves in plasma heating in fusion research, plasma and solid state diagnostics, particle accelerators and colliders, pump sources in lasers, material processing as well as in high power radars. This paper describes the experimental work done at Trombay for measurement of pulsed RFMR fields in the working area of a radiofrequency quadrupole (RFQ) accelerator with the use of a meter calibrated in continuous field and interprets the observed fields in the light of existing protection criteria for pulsed RFMR fields. (author)

Protease-Activated Receptor 4 (PAR4): A Promising Target for Antiplatelet Therapy.

Science.gov (United States)

Rwibasira Rudinga, Gamariel; Khan, Ghulam Jilany; Kong, Yi

2018-02-14

Cardiovascular diseases (CVDs) are currently among the leading causes of death worldwide. Platelet aggregation is a key cellular component of arterial thrombi and major cause of CVDs. Protease-activated receptors (PARs), including PAR1, PAR2, PAR3 and PAR4, fall within a subfamily of seven-transmembrane G-protein-coupled receptors (GPCR). Human platelets express PAR1 and PAR4, which contribute to the signaling transduction processes. In association with CVDs, PAR4 not only contributes to platelet activation but also is a modulator of cellular responses that serve as hallmarks of inflammation. Although several antiplatelet drugs are available on the market, they have many side effects that limit their use. Emerging evidence shows that PAR4 targeting is a safer strategy for preventing thrombosis and consequently may improve the overall cardiac safety profile. Our present review summarizes the PAR4 structural characteristics, activation mechanism, role in the pathophysiology of diseases and understanding the association of PAR4 targeting for improved cardiac protection. Conclusively, this review highlights the importance of PAR4 antagonists and its potential utility in different CVDs.

Painless, safe, and efficacious noninvasive skin tightening, body contouring, and cellulite reduction using multisource 3DEEP radiofrequency.

Science.gov (United States)

Harth, Yoram

2015-03-01

In the last decade, Radiofrequency (RF) energy has proven to be safe and highly efficacious for face and neck skin tightening, body contouring, and cellulite reduction. In contrast to first-generation Monopolar/Bipolar and "X -Polar" RF systems which use one RF generator connected to one or more skin electrodes, multisource radiofrequency devices use six independent RF generators allowing efficient dermal heating to 52-55°C, with no pain or risk of other side effects. In this review, the basic science and clinical results of body contouring and cellulite treatment using multisource radiofrequency system (Endymed PRO, Endymed, Cesarea, Israel) will be discussed and analyzed. © 2015 Wiley Periodicals, Inc.

Theoretical resolving power of a radiofrequency mass spectrometer

International Nuclear Information System (INIS)

Coc, A.; Le Gac, R.; Saint Simon, M. de; Thibault, C.; Touchard, F.

1988-01-01

Radiofrequency mass spectrometers of L.G. Smith's type can reach a resolving power of 10 6 -10 7 and a precision of 10 -9 -10 -10 . The resolving power, shape of peaks and limitations are described. As an example, the spectrometer to be used in an experiment aimed at measuring the anti p/p mass ratio is considered. (orig.)

Radio-frequency transparent demodulation for broadband hybrid wireless-optical links

DEFF Research Database (Denmark)

Zibar, Darko; Sambaraju, Rakesh; Alemany, Ruben

2010-01-01

A novel demodulation technique which is transparent to radio-frequency (RF) carrier frequency is presented and experimentally demonstrated for multigigabit wireless signals. The presented demodulation technique employs optical single-sideband filtering, coherent detection, and baseband digital si...

Radiofrequency electromagnetic fields in the Cookridge area of Leeds

CERN Document Server

Fuller, K; Judd, P M; Lowe, A J; Shaw, J

2002-01-01

On the 8 and 9 May 2002 representatives of the National Radiological Protection Board (NRPB) performed a radiofrequency electromagnetic field survey in the Cookridge area of Leeds in order to assess exposure to radio signals from transmitters mounted on a water tower/a lattice tower and a radio station tower. Guidelines on limiting exposure to radio signals have been published by NRPB and the International Commission on Non-Ionizing Radiation Protection (ICNIRP). These guidelines are designed to prevent established adverse effects on human health. During this survey, the total exposures due to all radio signals from 30 MHz to 18000 MHz (18 GHz) were measured. This frequency range was chosen as it includes mobile phone base station transmissions, which are at around 900 and 1800 MHz and super high frequency (SHF) transmissions from most of the large microwave dish antennas mounted on the towers. In addition, other major sources of radiofrequency electromagnetic fields in the environment such as broadcast radio...

PAR1 activation affects the neurotrophic properties of Schwann cells.

Science.gov (United States)

Pompili, Elena; Fabrizi, Cinzia; Somma, Francesca; Correani, Virginia; Maras, Bruno; Schininà, Maria Eugenia; Ciraci, Viviana; Artico, Marco; Fornai, Francesco; Fumagalli, Lorenzo

2017-03-01

Protease-activated receptor-1 (PAR1) is the prototypic member of a family of four G-protein-coupled receptors that signal in response to extracellular proteases. In the peripheral nervous system, the expression and/or the role of PARs are still poorly investigated. High PAR1 mRNA expression was found in the rat dorsal root ganglia and the signal intensity of PAR1 mRNA increased in response to sciatic nerve transection. In the sciatic nerve, functional PAR1 receptor was reported at the level of non-compacted Schwann cell myelin microvilli of the nodes of Ranvier. Schwann cells are the principal population of glial cells of the peripheral nervous system which myelinate axons playing an important role during axonal regeneration and remyelination. The present study was undertaken in order to determine if the activation of PAR1 affects the neurotrophic properties of Schwann cells. Our results suggest that the stimulation of PAR1 could potentiate the Schwann cell ability to favour nerve regeneration. In fact, the conditioned medium obtained from Schwann cell cultures challenged with a specific PAR1 activating peptide (PAR1 AP) displays increased neuroprotective and neurotrophic properties with respect to the culture medium from untreated Schwann cells. The proteomic analysis of secreted proteins in untreated and PAR1 AP-treated Schwann cells allowed the identification of factors differentially expressed in the two samples. Some of them (such as macrophage migration inhibitory factor, matrix metalloproteinase-2, decorin, syndecan 4, complement C1r subcomponent, angiogenic factor with G patch and FHA domains 1) appear to be transcriptionally regulated after PAR1 AP treatment as shown by RT-PCR. Copyright © 2017 Elsevier Inc. All rights reserved.

The Inactivation of Escherichia Coli Bacteria Labelled with Tritiated Thymidine; Inactivation de Bacteries Escherichia Coli Marquees par la Thymidine Tritiee; 0418 043d 0414 ; Inactivacion de Escherichia Coli Marcada con Timidina Tritiada

Energy Technology Data Exchange (ETDEWEB)

Apelgot, Sonia [Institut du Radium, Laboratoire Curie, Paris (France)

1962-02-15

'efficacite de chaque atome desintegre pour tuer une bacterie est tres faible. Le calcul du nombre de paires d'ions crees, a l'inactivation, dans la bacterie par les particules {beta} emises au cours de la transmutation des atomes de {sup 3}H montre que ce nombre est comparable a celui laisse dans le cas des rayons X. Il semble que le suicide provoque par les desintegrations de {sup 3}H soit lie directement, a - 196 Degree-Sign C, a l'ionisation produite, dans l'ADN bacterien, par des particules {beta} emises, et a 0 Degree-Sign C, a la transmutation des atomes de {sup 3}H elle-meme. (author) [Spanish] tritiada. Se ha marcado con timidina tritiada el acido desoxirribonucleico de bacterias de la cepa B; thy {sup -}/Sr, que requieren timidina y son resistentes a la estreptomicina. Las mediciones de radiactividad se efectuaron con un contador de centelleador liquido, provisto de dos fotomultiplicadores montados en coincidencia. En las condiciones experimentales utilizadas, el rendimiento de recuento fue del 4,5% y la actividad de fondo, de 130 impulsos por minuto. Las bacterias radiactivas se guardaron a 0 Degree-Sign C y a - 196 Degree-Sign C en ampollas soldadas y se estudio su supervivencia. Los experimentos demuestran que las bacterias radiactivas son inactivadas exponencialmente, en funcion del numero de atomos de tritio que se desintegran. La inactivacion depende tambien de la temperatura. En ambos casos, se determino el efecto letal por transmutacion nuclear comprobandose que es muy debil. Se calculo el numero de pares ionicos generados por las particulas beta emitidas a consecuencia de la transmutacion del {sup 3}H y se observo que es comparable al obtenido en el caso de los rayos X. La muerte, causada por las desintegraciones del {sup 3}H, parece estar directamente relacionada con a ionizacion producida por las particulas beta en el acido desoxirribonucleico de las bacterias. (author) [Russian] Bakterii shtamma B{sup 3}{sub 1} thy{sup -}/Sr, nuzhdajushhiesja v timine i

Protease-Activated Receptor 4 (PAR4: A Promising Target for Antiplatelet Therapy

Directory of Open Access Journals (Sweden)

Gamariel Rwibasira Rudinga

2018-02-01

Full Text Available Cardiovascular diseases (CVDs are currently among the leading causes of death worldwide. Platelet aggregation is a key cellular component of arterial thrombi and major cause of CVDs. Protease-activated receptors (PARs, including PAR1, PAR2, PAR3 and PAR4, fall within a subfamily of seven-transmembrane G-protein-coupled receptors (GPCR. Human platelets express PAR1 and PAR4, which contribute to the signaling transduction processes. In association with CVDs, PAR4 not only contributes to platelet activation but also is a modulator of cellular responses that serve as hallmarks of inflammation. Although several antiplatelet drugs are available on the market, they have many side effects that limit their use. Emerging evidence shows that PAR4 targeting is a safer strategy for preventing thrombosis and consequently may improve the overall cardiac safety profile. Our present review summarizes the PAR4 structural characteristics, activation mechanism, role in the pathophysiology of diseases and understanding the association of PAR4 targeting for improved cardiac protection. Conclusively, this review highlights the importance of PAR4 antagonists and its potential utility in different CVDs.

Sphenopalatine ganglion treatment with radiofrequency in a Sluder syndrome young patient

Directory of Open Access Journals (Sweden)

Carmelo Costa

2014-12-01

Full Text Available Sluder's neuralgia or sphenopalatine ganglion neuralgia is a pain syndrome first described by Sluder in 1908. The clinical picture is characterised by pain starting around the eye and the route of nose. Typically the pain is accompanied by parasympathetic disautonomic signs such as lacrimation and/or rhinorrhea. However, many official headache classifications do not mention the Sluder's neuralgia at all, which is instead classified as a cluster headache (CH. In case of resistance to pharmacological management pain the physician could recur to sphenopalatine ganglion (GSP neurolytic block with continuous radiofrequency (CRF or its no ablative alternative with pulsed radiofrequency (PRF. We are presenting a case of a 16-year-old woman who suffered from a typical Sluder's neuralgia successfully treated with GSP PRF.

Vote par sondage uniforme incorruptible

OpenAIRE

Blanchard , Nicolas

2016-01-01

International audience; Introduit en 2012 par David Chaum, le vote par sondage uniforme (random-sample voting) est un protocole de vote basé sur un choix d'une sous-population représentative , permettant de limiter les coûts tout en ayant de nombreux avantages, principalement lorsqu'il est couplé a d'autres techniques comme ThreeBallot. Nous analysons un problème de corruptibilité potentielle où les votants peuvent vendre leur vote au plus offrant et proposons une variation du protocole reméd...

Influence of transcatheter hepatic artery embolization using iodized oil on radiofrequency ablation of hepatic neoplasms

International Nuclear Information System (INIS)

Du Xilin; Ma Qingjiu; Wang Yiqing; Wang Zhimin; Zhang Hongxin

2004-01-01

Objective: To observe the effect of iodized oil on radiofrequency thermal ablation (RFA) of hepatic neoplasms by using a cluster array of ten separate electrodes. Methods: The patients were divided into 2 groups, group A with transcatheter hepatic artery embolization, group B without transcatheter hepatic artery embolization. All patients were undergone radiofrequency ablation of hepatic neoplasms. Results: The time of RFA for group A was (9 ± 2.1) minutes, showing the diameter of necrosis of (5.3 ± 1.4) cm. The time of RFA for group B was (16 ± 4. 6) minutes demonstrating the diameter of necrosis of (3.5 ± 1.8) cm (P<0.01). Conclusions: These findings suggest that radiofrequency thermal ablation of hepatic neoplasms with transcatheter hepatic artery embolization using iodized oil might improve the safety and synergic effect

Radiofrequency attenuator and method

Science.gov (United States)

Warner, Benjamin P [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM; Burrell, Anthony K [Los Alamos, NM; Agrawal, Anoop [Tucson, AZ; Hall, Simon B [Palmerston North, NZ

2009-01-20

Radiofrequency attenuator and method. The attenuator includes a pair of transparent windows. A chamber between the windows is filled with molten salt. Preferred molten salts include quarternary ammonium cations and fluorine-containing anions such as tetrafluoroborate (BF.sub.4.sup.-), hexafluorophosphate (PF.sub.6.sup.-), hexafluoroarsenate (AsF.sub.6.sup.-), trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Radicals or radical cations may be added to or electrochemically generated in the molten salt to enhance the RF attenuation.

Radiofrequency spark chambers and delay line resonators

International Nuclear Information System (INIS)

Sayag, Jacques

1971-01-01

According to a suggestion of A. Kastler, a spark chamber was excited by an undamped radiofrequency pulse and tracks about 1 mm wide obtained; the result was interpreted by computation of the coefficients of electronic amplification and partial ambipolar diffusion. This work led us to the construction of a new fast triggering undamped wave-train generator of very high tension (patent taken out by the C.E.A. under the no.: EN 7 134 650 the 27.9.1971). Since this apparatus uses a resonant storage line, its design implied a precise knowledge of high impedance delay lines. The experimental radiofrequency spectra of the input impedance of opened or short-circuited lines were plotted completely and analysed by the circuits theory, new measuring methods were established, dispersion relations accurately checked and the equivalence of the formulas, within the third order, with theses of Debye's Dipolar Absorption demonstrated. General properties of Hilbert's transform were also investigated. From the experimental point of view, the electromagnetic energy storage process was extended to the case of a liquid nitrogen-immersed resonant delay line. The good behavior of the cryogenic experiment, where the main difficulty of icing was overcame by the construction of special electrodes, offers great promise for extrapolation to superconductivity. (author) [fr

Capacitively coupled radio-frequency discharges in nitrogen at low pressures

KAUST Repository

Alves, Luí s Lemos; Marques, Luí s S A; Pintassilgo, Carlos D.; Wattieaux, Gaë tan; Es-sebbar, Et-touhami; Berndt, Johannes; Kovačević, Eva; Carrasco, Nathalie; Boufendi, Laï fa; Cernogora, Guy

2012-01-01

This paper uses experiments and modelling to study capacitively coupled radio-frequency (rf) discharges in pure nitrogen, at 13.56MHz frequency, 0.11 mbar pressures and 230W coupled powers. Experiments performed on two similar (not twin) setups

The double par locus of virulence factor pB171: DNA segregation is correlated with oscillation of ParA

DEFF Research Database (Denmark)

Ebersbach, G; Gerdes, K; Charbon, Gitte Ebersbach

2001-01-01

Prokaryotic plasmids and chromosomes encode partitioning (par) loci that segregate DNA to daughter cells before cell division. Recent database analyses showed that almost all known par loci encode an ATPase and a DNA-binding protein, and one or more cis-acting regions where the proteins act. All...

The role of pars flaccida in human middle ear sound transmission.

Science.gov (United States)

Aritomo, H; Goode, R L; Gonzalez, J

1988-04-01

The role of the pars flaccida in middle ear sound transmission was studied with the use of twelve otoscopically normal, fresh, human temporal bones. Peak-to-peak umbo displacement in response to a constant sound pressure level at the tympanic membrane was measured with a noncontacting video measuring system capable of repeatable measurements down to 0.2 micron. Measurements were made before and after pars flaccida modifications at 18 frequencies between 100 and 4000 Hz. Four pars flaccida modifications were studied: (1) acoustic insulation of the pars flaccida to the ear canal with a silicone rubber baffle, (2) stiffening the pars flaccida with cyanoacrylate cement, (3) decreasing the tension of the pars flaccida with a nonperforating incision, and (4) perforation of the pars flaccida. All of the modifications (except the perforation) had a minimal effect on umbo displacement; this seems to imply that the pars flaccida has a minor acoustic role in human beings.

First experience using navigation-guided radiofrequency kyphoplasty for sacroplasty in sacral insufficiency fractures

Energy Technology Data Exchange (ETDEWEB)

Klingler, J.H.; Kluge, P.; Sircar, R.; Kogias, E.; Scholz, C.; Krueger, M.T.; Scheiwe, C.; Hubbe, U. [Freiburg Univ. Medical Center, Freiburg (Germany). Dept. of Neurosurgery

2013-08-15

Purpose: To evaluate the efficacy and safety of navigation-guided radiofrequency kyphoplasty for sacroplasty in patients with sacral insufficiency fractures. Methods: In this single-center retrospective observational study, four consecutive patients with sacral insufficiency fractures were treated with navigation-guided radiofrequency kyphoplasty for sacroplasty between April 2010 and May 2012. Symptom characteristics, pain duration and pain intensity were recorded for each patient. Cement extravasation was evaluated in thin-sliced and triplanar reconstructed CT scans of the sacrum. Results: Four female patients with painful sacral insufficiency fractures and extensive osteopenic areas significantly improved from an average pre-treatment VAS score of 8.3 {+-} 0.5 to 2.3 {+-} 1.0 (p < 0.001) on the first postoperative day and to 1.3 {+-} 1.9 (p < 0.004) at follow-up (mean, 20.1 weeks). Slight cement extravasations were observed without evidence of being symptomatic. No major complications or procedure-related morbidity were noted. Conclusion: From the limited experience in four patients, navigation-guided radiofrequency kyphoplasty appears to be a safe and effective treatment option for sacral insufficiency fractures even though asymptomatic cement extravasation was noted. The use of navigation based on intraoperative 3 D images simplifies the positioning of the navigated bone needles via the long axis approach. The radiofrequency kyphoplasty system provides the possibility to administer a sufficient amount of bone cement with a well-defined viscosity over the entire period of the procedure leading to high security and low cement extravasation. Sacroplasty provides rapid and enduring pain relief and facilitates prompt mobilization. (orig.)

A new catheter design for combined radiofrequency ablation and optoacoustic treatment monitoring using copper-coated light-guides

Science.gov (United States)

Rebling, Johannes; Oyaga Landa, Francisco Javier; Deán-Ben, Xosé Luis; Razansky, Daniel

2018-02-01

Electrosurgery, i.e. the application of radiofrequency current for tissue ablation, is a frequently used treatment for many cardiac arrhythmias. Electrophysiological and anatomic mapping, as well as careful radiofrequency power control typically guide the radiofrequency ablation procedure. Despite its widespread application, accurate monitoring of the lesion formation with sufficient spatio-temporal resolution remains challenging with the existing imaging techniques. We present a novel integrated catheter for simultaneous radiofrequency ablation and optoacoustic monitoring of the lesion formation in real time and 3D. The design combines the delivery of both electric current and optoacoustic excitation beam in a single catheter consisting of copper-coated multimode light-guides and its manufacturing is described in detail. The electrical current causes coagulation and desiccation while the excitation light is locally absorbed, generating OA responses from the entire treated volume. The combined ablation-monitoring capabilities were verified using ex-vivo bovine tissue. The formed ablation lesions showed a homogenous coagulation while the ablation was monitored in realtime with a volumetric frame rate of 10 Hz over 150 seconds.

Effect of cell-phone radiofrequency on angiogenesis and cell invasion in human head and neck cancer cells.

Science.gov (United States)

Alahmad, Yaman M; Aljaber, Mohammed; Saleh, Alaaeldin I; Yalcin, Huseyin C; Aboulkassim, Tahar; Yasmeen, Amber; Batist, Gerald; Moustafa, Ala-Eddin Al

2018-05-13

Today, the cell phone is the most widespread technology globally. However, the outcome of cell-phone radiofrequency on head and neck cancer progression has not yet been explored. The chorioallantoic membrane (CAM) and human head and neck cancer cell lines, FaDu and SCC25, were used to explore the outcome of cell-phone radiofrequency on angiogenesis, cell invasion, and colony formation of head and neck cancer cells, respectively. Western blot analysis was used to investigate the impact of the cell phone on the regulation of E-cadherin and Erk1/Erk2 genes. Our data revealed that cell-phone radiofrequency promotes angiogenesis of the CAM. In addition, the cell phone enhances cell invasion and colony formation of human head and neck cancer cells; this is accompanied by a downregulation of E-cadherin expression. More significantly, we found that the cell phone can activate Erk1/Erk2 in our experimental models. Our investigation reveals that cell-phone radiofrequency could enhance head and neck cancer by stimulating angiogenesis and cell invasion via Erk1/Erk2 activation. © 2018 Wiley Periodicals, Inc.

Radiofrequency Wire Recanalization of Chronically Thrombosed TIPS

Energy Technology Data Exchange (ETDEWEB)

Majdalany, Bill S., E-mail: bmajdala@med.umich.edu [University of Michigan Health System, Division of Interventional Radiology, Department of Radiology (United States); Elliott, Eric D., E-mail: eric.elliott@osumc.edu [The Ohio State University Wexner Medical Center, Division of Interventional Radiology, Department of Radiology (United States); Michaels, Anthony J., E-mail: Anthony.michaels@osumc.edu; Hanje, A. James, E-mail: James.Hanje@osumc.edu [The Ohio State University Wexner Medical Center, Division of Gastroenterology and Hepatology, Department of Medicine (United States); Saad, Wael E. A., E-mail: wsaad@med.umich.edu [University of Michigan Health System, Division of Interventional Radiology, Department of Radiology (United States)

2016-07-15

Radiofrequency (RF) guide wires have been applied to cardiac interventions, recanalization of central venous thromboses, and to cross biliary occlusions. Herein, the use of a RF wire technique to revise chronically occluded transjugular intrahepatic portosystemic shunts (TIPS) is described. In both cases, conventional TIPS revision techniques failed to revise the chronically thrombosed TIPS. RF wire recanalization was successfully performed through each of the chronically thrombosed TIPS, demonstrating initial safety and feasibility in this application.

Papillary thyroid carcinoma treated with radiofrequency ablation in a patient with hypertrophic cardiomyopathy: A case report

Energy Technology Data Exchange (ETDEWEB)

Sun, Jian Yi; Liu, Xiao Sun; Zhang, Qing; Hong, Yan Yun; Song, Bin; Teng, Xiao Dong; Yu, Ji Ren [The First Affiliated Hospital, Medical College, Zhejiang University, Hangzhou (China)

2016-07-15

Standard therapy has not been established for thyroid cancer when a thyroidectomy is contraindicated due to systemic disease. Herein, we reported a patient who had hypertrophic cardiomyopathy and papillary thyroid carcinoma treated by radiofrequency ablation because of inability to tolerate a thyroidectomy. Radiofrequency ablation can be used to treat thyroid cancer when surgery is not feasible, although the long-term outcome needs further observation.

Papillary Thyroid Carcinoma Treated with Radiofrequency Ablation in a Patient with Hypertrophic Cardiomyopathy: A Case Report

Energy Technology Data Exchange (ETDEWEB)

Sun, Jianyi; Liu, Xiaosun; Zhang, Qing; Hong, Yanyun; Song, Bin [Department of Gastrointestinal and Thyroid Surgery, The First Affiliated Hospital, Medical College, Zhejiang University, Hangzhou 310003 (China); Teng, Xiaodong [Department of Pathology, The First Affiliated Hospital, Medical College, Zhejiang University, Hangzhou 310003 (China); Yu, Jiren [Department of Gastrointestinal and Thyroid Surgery, The First Affiliated Hospital, Medical College, Zhejiang University, Hangzhou 310003 (China)

2016-11-01

Standard therapy has not been established for thyroid cancer when a thyroidectomy is contraindicated due to systemic disease. Herein, we reported a patient who had hypertrophic cardiomyopathy and papillary thyroid carcinoma treated by radiofrequency ablation because of inability to tolerate a thyroidectomy. Radiofrequency ablation can be used to treat thyroid cancer when surgery is not feasible, although the long-term outcome needs further observation.

Experimental and clinical studies with radiofrequency-induced thermal endometrial ablation for functional menorrhagia

Energy Technology Data Exchange (ETDEWEB)

Phipps, J.H.; Lewis, B.V.; Prior, M.V.; Roberts, T. (Watford General Hospital, Herts (England))

1990-11-01

A method of ablating the endometrium has been introduced into clinical practice that uses radiofrequency electromagnetic energy to heat the endometrium, using a probe inserted through the cervix. Preliminary studies suggest that over 80% of patients treated will develop either amenorrhea or a significant reduction in flow. The advantages of radiofrequency endometrial ablation over laser ablation or resection are the avoidance of intravascular fluid absorption, simplicity (no special operative hysteroscopic skills are required), speed of operation, and reduced cost compared with the Nd:YAG laser. In this paper, we describe the experimental studies performed during development of this new technique.

Tunable radio-frequency photonic filter based on an actively mode-locked fiber laser.

Science.gov (United States)

Ortigosa-Blanch, A; Mora, J; Capmany, J; Ortega, B; Pastor, D

2006-03-15

We propose the use of an actively mode-locked fiber laser as a multitap optical source for a microwave photonic filter. The fiber laser provides multiple optical taps with an optical frequency separation equal to the external driving radio-frequency signal of the laser that governs its repetition rate. All the optical taps show equal polarization and an overall Gaussian apodization, which reduces the sidelobes. We demonstrate continuous tunability of the filter by changing the external driving radio-frequency signal of the laser, which shows good fine tunability in the operating range of the laser from 5 to 10 GHz.

Thermistor guided radiofrequency ablation of atrial insertion sites in patients with accessory pathways.

Science.gov (United States)

Tracy, C M; Moore, H J; Solomon, A J; Rodak, D J; Fletcher, R D

1995-11-01

Radiofrequency ablation has gained acceptance in the treatment of patients with symptomatic Wolff-Parkinson-White syndrome. The purpose of this study was to characterize the relation between temperature and other electroconductive parameters in patients undergoing atrial insertion accessory pathway ablation utilizing a thermistor equipped catheter. The mean temperature and power at sites of atrial insertion ablation are lower than has been previously associated with creation of radiofrequency lesions in the ventricle. While high cavitary blood flow in the atrium may result in cooling, the thinner atrial tissue may require less energy to achieve adequate heating than ventricular myocardium.

Outcomes of Radiofrequency Ablation for Dysplastic Barrett's Esophagus: A Comprehensive Review

Science.gov (United States)

Iabichino, Giuseppe; Arena, Monica; Consolo, Pierluigi; Morace, Carmela; Opocher, Enrico; Mangiavillano, Benedetto

2016-01-01

Barrett's esophagus is a condition in which the normal squamous lining of the esophagus has been replaced by columnar epithelium containing intestinal metaplasia induced by recurrent mucosal injury related to gastroesophageal reflux disease. Barrett's esophagus is a premalignant condition that can progress through a dysplasia-carcinoma sequence to esophageal adenocarcinoma. Multiple endoscopic ablative techniques have been developed with the goal of eradicating Barrett's esophagus and preventing neoplastic progression to esophageal adenocarcinoma. For patients with high-grade dysplasia or intramucosal neoplasia, radiofrequency ablation with or without endoscopic resection for visible lesions is currently the most effective and safe treatment available. Recent data demonstrate that, in patients with Barrett's esophagus and low-grade dysplasia confirmed by a second pathologist, ablative therapy results in a statistically significant reduction in progression to high-grade dysplasia and esophageal adenocarcinoma. Treatment of dysplastic Barrett's esophagus with radiofrequency ablation results in complete eradication of both dysplasia and of intestinal metaplasia in a high proportion of patients with a low incidence of adverse events. A high proportion of treated patients maintain the neosquamous epithelium after successful treatment without recurrence of intestinal metaplasia. Following successful endoscopic treatment, endoscopic surveillance should be continued to detect any recurrent intestinal metaplasia and/or dysplasia. This paper reviews all relevant publications on the endoscopic management of Barrett's esophagus using radiofrequency ablation. PMID:28070182

Automated Estimation of Melanocytic Skin Tumor Thickness by Ultrasonic Radiofrequency Data.

Science.gov (United States)

Andrekute, Kristina; Valiukeviciene, Skaidra; Raisutis, Renaldas; Linkeviciute, Gintare; Makstiene, Jurgita; Kliunkiene, Renata

2016-05-01

High-frequency (>20-MHz) ultrasound (US) is a noninvasive preoperative tool for assessment of melanocytic skin tumor thickness. Ultrasonic melanocytic skin tumor thickness estimation is not always easy and is related to the experience of the clinician. In this article, we present an automated thickness measurement method based on time-frequency analysis of US radiofrequency signals. The study was performed on 52 thin (≤1-mm) melanocytic skin tumors (46 melanocytic nevi and 6 melanomas). Radiofrequency signals were obtained with a single-element focused transducer (fundamental frequency, 22 MHz; bandwidth, 12-28 MHz). The radiofrequency data were analyzed in the time-frequency domain to make the tumor boundaries more noticeable. The thicknesses of the tumors were evaluated by 3 different metrics: histologically measured Breslow thickness, manually measured US thickness, and automatically measured US thickness. The results showed a higher correlation coefficient between the automatically measured US thickness and Breslow thickness (r= 0.83; Pmeasured US thickness (r = 0.68; P measurement algorithm was 96.55%, and the specificity was 78.26% compared with histologic measurement. The sensitivity of the manually measured US thickness was 75.86%, and the specificity was 73.91%. The efficient automated tumor thickness measurement method developed could be used as a tool for preoperative assessment of melanocytic skin tumor thickness. © 2016 by the American Institute of Ultrasound in Medicine.

Movement and equipositioning of plasmids by ParA filament disassembly

DEFF Research Database (Denmark)

Ringgaard, Simon; van Zon, Jeroen; Howard, Martin

2009-01-01

, plasmids consistently migrate behind disassembling ParA cytoskeletal structures, suggesting that ParA filaments pull plasmids by depolymerization. The perpetual cycles of ParA assembly and disassembly result in continuous relocation of plasmids, which, on time averaging, results in equidistribution...

PAR-1 contributes to the innate immune response during viral infection

Science.gov (United States)

Antoniak, Silvio; Owens, A. Phillip; Baunacke, Martin; Williams, Julie C.; Lee, Rebecca D.; Weithäuser, Alice; Sheridan, Patricia A.; Malz, Ronny; Luyendyk, James P.; Esserman, Denise A.; Trejo, JoAnn; Kirchhofer, Daniel; Blaxall, Burns C.; Pawlinski, Rafal; Beck, Melinda A.; Rauch, Ursula; Mackman, Nigel

2013-01-01

Coagulation is a host defense system that limits the spread of pathogens. Coagulation proteases, such as thrombin, also activate cells by cleaving PARs. In this study, we analyzed the role of PAR-1 in coxsackievirus B3–induced (CVB3-induced) myocarditis and influenza A infection. CVB3-infected Par1–/– mice expressed reduced levels of IFN-β and CXCL10 during the early phase of infection compared with Par1+/+ mice that resulted in higher viral loads and cardiac injury at day 8 after infection. Inhibition of either tissue factor or thrombin in WT mice also significantly increased CVB3 levels in the heart and cardiac injury compared with controls. BM transplantation experiments demonstrated that PAR-1 in nonhematopoietic cells protected mice from CVB3 infection. Transgenic mice overexpressing PAR-1 in cardiomyocytes had reduced CVB3-induced myocarditis. We found that cooperative signaling between PAR-1 and TLR3 in mouse cardiac fibroblasts enhanced activation of p38 and induction of IFN-β and CXCL10 expression. Par1–/– mice also had decreased CXCL10 expression and increased viral levels in the lung after influenza A infection compared with Par1+/+ mice. Our results indicate that the tissue factor/thrombin/PAR-1 pathway enhances IFN-β expression and contributes to the innate immune response during single-stranded RNA viral infection. PMID:23391721

Effect of percutaneous renal sympathetic nerve radiofrequency ablation in patients with severe heart failure.

Science.gov (United States)

Dai, Qiming; Lu, Jing; Wang, Benwen; Ma, Genshan

2015-01-01

This study aimed to investigate the clinical feasibility and effects of percutaneous renal sympathetic nerve radiofrequency ablation in patients with heart failure. A total of 20 patients with heart failure were enrolled, aged from 47 to 75 years (63±10 years). They were divided into the standard therapy (n = 10), and renal nerve radiofrequency ablation groups (n = 10). There were 15 males and 5 female patients, including 8 ischemic cardiomyopathy, 8 dilated cardiomyopathy, and 8 hypertensive cardiopathy. All of the patients met the criteria of New York Heart Association classes III-IV cardiac function. Patients with diabetes and renal failure were excluded. Percutaneous renal sympathetic nerve radiofrequency ablation was performed on the renal artery wall under X-ray guidance. Serum electrolytes, neurohormones, and 24 h urine volume were recorded 24 h before and after the operation. Echocardiograms were performed to obtain left ventricular ejection fraction at baseline and 6 months. Heart rate, blood pressure, symptoms of dyspnea and edema were also monitored. After renal nerve ablation, 24 h urine volume was increased, while neurohormone levels were decreased compared with those of pre-operation and standard therapy. No obvious change in heart rate or blood pressure was recorded. Symptoms of heart failure were improved in patients after the operation. No complications were recorded in the study. Percutaneous renal sympathetic nerve radiofrequency ablation may be a feasible, safe, and effective treatment for the patients with severe congestive heart failure.

Radiofrequency denervation of the hip joint for pain management: case report and literature review.

Science.gov (United States)

Gupta, Gaurav; Radhakrishna, Mohan; Etheridge, Paul; Besemann, Markus; Finlayson, Robert J

2014-01-01

A 55-year-old male presented with severe pain and functional limitations as a result of left hip osteoarthritis. He had failed multiple treatments while waiting for a hip arthroplasty, including physical therapy, medications, and various intra-articular injections. Thermal radiofrequency lesioning of the obturator and femoral articular branches to the hip joint was offered in the interim. To our knowledge, this is the first report to describe an inferior-lateral approach for lesioning the obturator branch, the clinical application of successive lesions to increase denervation area, and outcomes in a patient receiving a second treatment with previously good results. To discuss relevant and technical factors for this specific case, we reviewed previous literature on hip joint radiofrequency and critically evaluated previous anatomic studies in the context of radiofrequency. The first treatment provided significant benefit for a period of 6 months. A second treatment was employed providing only mild to moderate benefit until his joint replacement surgery 4 months later. Literature review revealed studies of low quality secondary to small sample sizes, patient selection methodology, inclusion of patients with heterogenous etiologies for pain, variable needle placement techniques, and lack of measurement of functional outcomes. Case report and low quality studies in existing literature. Hip joint radiofrequency denervation is a promising avenue for adjunctive treatment of hip pain. Further cadaveric studies are required to clarify a multitude of technical parameters. Once these are well defined, future clinical studies should consider pain, functional, and economic outcomes in their design.

Radiofrequency Ablation versus Cryoablation in the Treatment of Paroxysmal Atrial Fibrillation: A Meta-Analysis

Directory of Open Access Journals (Sweden)

Ali H. Hachem

2018-01-01

Full Text Available Background. Pulmonary vein isolation is commonly performed using radiofrequency energy with cryoablation gaining acceptance. We performed a meta-analysis of randomized controlled trials which compared radiofrequency versus cryoablation for patients with atrial fibrillation. Methods. A systematic search strategy identified both published and unpublished articles from inception to November 10, 2016, in multiple databases. The primary outcomes for this meta-analysis were long-term freedom from atrial fibrillation at 12-month follow-up and overall postoperative complication rates. For all included studies, the methodological quality was assessed through the Cochrane Collaboration’s tool for risk of bias. Results. A total of 247 articles were identified with eight being included in this review as they satisfied the prespecified inclusion criteria. Overall, there was no significant difference in freedom from atrial fibrillation at ≥12-month follow-up between those receiving cryoballoon and radiofrequency ablation, respectively (OR = 0.98, CI = 0.67–1.43, I2 = 56%, p=0.90. Additionally, the secondary outcomes of duration of ablation, fluoroscopy time, and ablation time failed to reach significance. Cryoballoon ablation had significantly greater odds of postoperative phrenic nerve injury at 12-month follow-up. Conclusions. Our meta-analysis suggests that cryoballoon ablation provides comparable benefits with regard to freedom from atrial fibrillation at medium-term follow-up, fluoroscopy time, ablation time, operative duration, and overall complication rate in comparison to radiofrequency ablation.

Radiofrequency catheter ablation for electrical storm in a patient with dilated cardiomyopathy.

Science.gov (United States)

Kolettis, Theofilos M; Naka, Katerina K; Katsouras, Christos S

2005-01-01

We report a case of successful radiofrequency catheter ablation in a patient with dilated cardiomyopathy, who presented with multiple, haemodynamically poorly tolerated episodes of monomorphic ventricular tachycardia, resistant to antiarrhythmic drug treatment. The ablation procedure consisted of focal ablation of three mapped left ventricular sites, using pace and activation mapping. Additional linear ablation lesions were created across these sites. After the procedure, the patient remained free of tachycardia episodes and seven days post-ablation he underwent implantation of a cardioverter-defibrillator. During a twelve-month follow-up period, the patient has remained free of monomorphic ventricular tachycardia episodes. Radiofrequency catheter ablation is feasible in electrical storm, using conventional mapping techniques, even in haemodynamically unstable tachycardias.

Effect of power modulation on properties of pulsed capacitively coupled radiofrequency discharges

International Nuclear Information System (INIS)

Samara, V; Bowden, M D; Braithwaite, N St J

2010-01-01

We describe measurements of plasma properties of pulsed, low pressure, capacitively coupled discharges operated in argon. The study aims to determine the effect of modulating the radiofrequency power during the discharge part of the pulse cycle. Measurements of local electron density and optical emission were made in capacitively coupled rf discharges generated in a Gaseous Electronics Conference (GEC) reference reactor. Gas pressure was in the range 7-70 Pa, rf power in the range 1-100 W and pulse durations in the range 10 μs-100 ms. The results indicate that the ignition and afterglow decay processes in pulsed discharges can be controlled by modulating the shape of applied radiofrequency pulse.

Spectroscopic photoacoustic imaging of radiofrequency ablation in the left atrium

NARCIS (Netherlands)

S. Iskander-Rizk (Sophinese); P. Kruizinga (Pieter); A.F.W. van der Steen (Ton); G. van Soest (Gijs)

2018-01-01

textabstractCatheter-based radiofrequency ablation for atrial fibrillation has long-term success in 60-70% of cases. A better assessment of lesion quality, depth, and continuity could improve the procedure’s outcome. We investigate here photoacoustic contrast between ablated and healthy atrial-wall

Clinical application of radiofrequency ablation combined with bronchial artery infusion of docetaxel in treating non-small cell lung cancer

International Nuclear Information System (INIS)

Lu Xiong; Chen Fang; Lin Yun; Tan Taikang; Wei Wei

2010-01-01

Objective: To discuss the clinical application of radiofrequency ablation combined with bronchial artery infusion of docetaxel in treating non-small cell lung cancer and to summarize the experience of using this therapy in clinical practice. Methods: Radiofrequency ablation was performed in twenty-one patients with lung cancer. The diagnosis was confirmed by CT-guided percutaneous needle biopsy or bronchoscopic biopsy in all patients. One week after radiofrequency ablation treatment, bronchial artery infusion of docetaxel was conducted. The therapeutic results were observed and evaluated. Results: After the treatment, the lesion's size was markedly reduced and the clinical symptoms were dramatically improved in all patients. Conclusion: Radiofrequency ablation combined with bronchial artery infusion of docetaxel is a safe, effective and simple technique with excellent therapeutic results for the treatment of non-small cell lung cancer. It is really worth popularizing this technique in clinical practice. (authors)

Occupational exposure of NRM spectrometrists to static and radiofrequency fields

International Nuclear Information System (INIS)

Berlana, Tania; Ubeda, Alejandro

2017-01-01

Occupational exposure to static and radiofrequency fields emitted by nuclear magnetic resonance spectrometers was assessed through systematic field metering during operation of 19 devices in nine research centers. Whereas no measurable levels of radiofrequency radiation were registered outside the spectrometers, significant exposure to static field was detected, with maximum values recorded at the user s hand (B = 683.00 mT) and head thorax (B = 135.70 mT) during spectrometer manipulation. All values were well below the exposure limits set by the European standard for workers protection against the effects of acute field exposure only. As for potential effects of chronic exposure, waiting for more complete knowledge, adoption of technical and operational strategies for exposure minimizing is advisable. In this respect, the data revealed that compared with standard magnetic shielding, ultra-shield technology allows a 20-65-fold reduction of the field strength received by the operator. (authors)

Physics of phenomena in the zone close to an underground nuclear explosion; Physique des phenomenes en zone proche des explosions nucleaires souterraines

Energy Technology Data Exchange (ETDEWEB)

Maury, J; Levret, C [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

1969-07-01

After a description of the phenomenology of underground explosions, the basic laws governing the propagation in the ground of the energy produced by the explosion are given. The reports considers hydrodynamics, the mechanics of solids, the equations of state for solids and gases in the case of very high and medium pressures, and the dynamical strength of solids. These various elements make it possible to draw up a system of equations which define completely the changes with time of the shock-wave produced in the ground by the explosion. (authors) [French] Apres une description de la phenomenologie des explosions souterraines, on expose les lois fondamentales regissant la propagation dans le sol de l'energie degagee par l'explosion. L'expose comprend des developpements sur l'hydrodynamique, la mecanique des solides, les equations d'etat des solides et des gaz, aux tres fortes et moyennes pressions, et sur la resistance dynamique des solides. Ces differents elements permettent d'ecrire un systeme d'equations qui definissent completement l'evolution dans le temps de l'onde de choc emise dans le sol par l'explosion. (auteurs)

Ion source with radiofrequency mass filter for sputtering purposes

International Nuclear Information System (INIS)

Sielanko, J.; Sowa, M.

1990-01-01

The Kaufman ion source with radiofrequency mass filter is described. The construction as well as operating characteristics of ion source are presented. The arrangement is suitable for range distribution measurements of implanted layers, where the sputtering rate has to be constant over the wide range of sputtering time. 4 figs., 17 refs. (author)

Radiofrequency identification: exploiting an old technology for measuring nurse time and motion.

Science.gov (United States)

Jones, Terry L

2012-09-01

A national campaign is underway to increase the amount of time staff nurses spend at the bedside of hospitalized patients through redesign of the work environment. This kind of work redesign requires robust data depicting what nurses do and how they spend their time. Historically, these kinds of data have been difficult, costly, and time consuming to collect. Wireless capture of data on the movement of humans within the work environment (ie, time and motion) is now possible through radiofrequency identification technology. When small tracking devices the size of a quarter are affixed to their clothing, the movement of nurses throughout a patient care unit can be monitored. The duration and frequency of patient interaction are captured along with the duration of time spent in other locations of interest to include nurses' station, supply room, medication room, doctors' station, electronic documentation stations, family waiting rooms, and the hallway. Patterns of nurse movement and time allocation can be efficiently identified, and the effects of staffing practices, workflows, and unit layout evaluated. Integration of radiofrequency identification time and motion data with other databases enables nurse leaders to link nursing time to important cost and quality outcomes. Nurse leaders should explore the usefulness of radiofrequency identification technology in addressing data needs for nurse time and motion.

[Clinical study of liver resection with bipolar radiofrequency device: Habib 4X].

Science.gov (United States)

Chen, Jian; Dong, Xin; Tang, Zhe; Gao, Shun-liang; Wu, Yu-lian; Fang, He-qing

2013-08-27

To assess the application value of a new radiofrequency device Habib 4X in liver resection. A retrospective study was performed during March 2010 to July 2011.Forty-four patients underwent liver resection with radiofrequency device Habib 4X and another 54 patients traditional liver resection.Intraoperative blood loss, blood transfusion, Pringle's maneuver requirement, liver parenchyma transaction time, liver function recovery, complications, mortality and recurrence were recorded. The mean resection time was (67 ± 22) min for Habib 4X group versus (93 ± 23) min for traditional group (P = 0.000). Pringle's maneuver was required in 10 patients (22.7%) for Habib 4X group and 31 (57.4%) for traditional group (P = 0.001). The mean blocking time was (7 ± 2) vs (18 ± 6) min (P = 0.001), mean blood loss volume (243 ± 132) vs (500 ± 421) ml (P = 0.002). Postoperative recovery of liver function was better in Habib 4X group than traditional group. None developed mortality in Habib 4X group. And no resection margin recurred during a 18-month follow-up. Bipolar radiofrequency device Habib 4X is recommended for pre-coagulation in hepatectomy. And the advantages of minimized blood loss and reduced resection time result in its lower rates of morbidity and mortality.

Peptide-Based Optical uPAR Imaging for Surgery

DEFF Research Database (Denmark)

Juhl, Karina; Christensen, Anders; Persson, Morten

2016-01-01

Near infrared intra-operative optical imaging is an emerging technique with clear implications for improved cancer surgery by enabling a more distinct delineation of the tumor margins during resection. This modality has the potential to increase the number of patients having a curative radical...... tumor resection. In the present study, a new uPAR-targeted fluorescent probe was developed and the in vivo applicability was evaluated in a human xenograft mouse model. Most human carcinomas express high level of uPAR in the tumor-stromal interface of invasive lesions and uPAR is therefore considered...... an ideal target for intra-operative imaging. Conjugation of the flourophor indocyanine green (ICG) to the uPAR agonist (AE105) provides an optical imaging ligand with sufficiently high receptor affinity to allow for a specific receptor targeting in vivo. For in vivo testing, human glioblastoma xenograft...

Safety of lumbar spine radiofrequency procedures in the presence of posterior pedicle screws: technical report of a cadaver study.

Science.gov (United States)

Gazelka, Halena M; Welch, Tasha L; Nassr, Ahmad; Lamer, Tim J

2015-05-01

To determine whether the thermal energy associated with lumbar spine radiofrequency neurotomy (RFN) performed near titanium and stainless steel pedicle screws is conducted to the pedicle screws or adjacent tissues, or both, thus introducing potential for thermal damage to those tissues. Cadaver study. Cadaver laboratory equipped with fluoroscopy, surgical spine implements, and radiofrequency generator. No live human subject; a fresh frozen (and thawed) cadaver torso was used for the study. Titanium and stainless steel pedicle screws were placed in the lumbar spine of a fresh frozen cadaver torso with real-time fluoroscopic guidance. Conventional RFN cannula placement was performed at the level of pedicle screws and a control (nonsurgically altered) lumbar level. Neurotomy was performed with conventional radiofrequency lesioning parameters. Temperatures were recorded at multiple sites through thermistor probes. Direct contact of the radiofrequency cannula with the pedicle screws during conventional RFN produced a substantial increase in temperature in the surrounding soft tissues. A small increase in temperature occurred at the same sites at the control level. Titanium and stainless steel pedicle screws are capable of sustaining large increases in temperature when the radiofrequency probe comes in contact with the screw. These results are suggestive that pedicle screws could serve as a possible source of tissue heating and thermal injury during RFN. Wiley Periodicals, Inc.

Graphene screen-printed radio-frequency identification devices on flexible substrates

NARCIS (Netherlands)

Arapov, K.; Jaakkola, K.; Ermolov, V.; Bex, G.; Rubingh, E.; Haque, S.; Sandberg, H.; Abbel, R.; de With, G.; Friedrich, H.

2016-01-01

Despite the great promise of printed flexible electronics from 2D crystals, and especially graphene, few scalable applications have been reported so far that can be termed roll-to-roll compatible. Here we combine screen printed graphene with photonic annealing to realize radio-frequency

Management of pain on hallux valgus with percutaneous intra-articular Pulse-Dose Radiofrequency.

Science.gov (United States)

Masala, Salvatore; Fiori, Roberto; Calabria, Eros; Raguso, Mario; de Vivo, Dominique; Cuzzolino, Alessandro; Simonetti, Giovanni

2017-01-01

The purpose of our study was to investigate the role of intra-articular pulse-dose radiofrequency in management of painful hallux valgus refractory to conservative therapies. Between November 2010 and April 2012, 51 patients (15 male, 36 female) with a median age of 71.4 years were included in our clinical trial. Under fluoroscopic guidance we introduced a 22 gauge 10 cm length cannula by a percutaneous access in the first metatarsophalangeal joint and its tip was placed intra-articularly. After removing the spindle, a radiofrequency needle with a 5 mm active tip was introduced. The following parameters were used: 1200 pulses at high voltage (45 V) with 20 msec duration followed by 480 msec silent phases. A great reduction in pain intensity was documented at 1 week, 1 month and 3 months after procedures. Pain intensity increased between 5 and 8 months after treatments, so we performed a second procedure in all patients between 7 months and 9 months since the first treatment. Also in this case we obtained a great reduction of pain intensity in the first 3 months after the procedure. Pain intensity returned at preprocedural values after 9 months after second procedure. No complications were observed. Our experience shows pulse-dose radiofrequency is a safe, repeatable and effective technique for managing patients with symptomatic hallux valgus in the short and medium term. Pulse-dose radiofrequency may improve pain control and quality of life in patients with hallux valgus refractory to conservative therapies. © 2014 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

Radiofrequency ablation of atrial tachyarrhythmias in adults with tetralogy of Fallot - predictors of success and outcome.

Science.gov (United States)

Ezzat, Vivienne A; Ryan, Matthew J; O'Leary, Justin; Ariti, Cono; Deanfield, John; Pandya, Bejal; Cullen, Shay; Walker, Fiona; Khan, Fakhar; Abrams, Dominic J; Lambiase, Pier D; Lowe, Martin D

2017-03-01

Adults with tetralogy of Fallot experience atrial tachyarrhythmias; however, there are a few data on the outcomes of radiofrequency ablation. We examined the characteristics, outcome, and predictors of recurrence of atrial tachyarrhythmias after radiofrequency ablation in tetralogy of Fallot patients. Methods/results Retrospective data were collected from 2004 to 2013. In total, 56 ablations were performed on 37 patients. We identified two matched controls per case: patients with tetralogy of Fallot but no radiofrequency ablation and not known to have atrial tachyarrhythmias. Acute success was 98%. Left atrial arrhythmias increased in frequency over time. The mean follow-up was 41 months; 78% were arrhythmia-free. Number of cardiac surgeries, age, and presence of atrial fibrillation were predictors of recurrence. Lone cavo-tricuspid isthmus-dependent flutter reduced the likelihood of atrial fibrillation. Right and left atria in patients with tetralogy of Fallot were larger in ablated cases than controls. NYHA class was worse in cases and improved after ablation; baseline status predicted death. Of matched non-ablated controls, a number of them had atrial fibrillation. These patients were excluded from the case-control study but analysed separately. Most of them had died during follow-up, whereas of the matched ablated cases all were alive and the majority in sinus rhythm. Patients with tetralogy of Fallot and atrial tachyarrhythmias have more dilated atria than those without atrial tachyarrhythmias. Radiofrequency ablation improves functional status. Left atrial ablation is more commonly required with repeat procedures. There is a high prevalence of atrial tachyarrhythmias, particularly atrial fibrillation, in patients with tetralogy of Fallot; early radiofrequency ablation may have a protective effect against this.

Dynamic Filament Formation by a Divergent Bacterial Actin-Like ParM Protein.

Directory of Open Access Journals (Sweden)

Anthony J Brzoska

Full Text Available Actin-like proteins (Alps are a diverse family of proteins whose genes are abundant in the chromosomes and mobile genetic elements of many bacteria. The low-copy-number staphylococcal multiresistance plasmid pSK41 encodes ParM, an Alp involved in efficient plasmid partitioning. pSK41 ParM has previously been shown to form filaments in vitro that are structurally dissimilar to those formed by other bacterial Alps. The mechanistic implications of these differences are not known. In order to gain insights into the properties and behavior of the pSK41 ParM Alp in vivo, we reconstituted the parMRC system in the ectopic rod-shaped host, E. coli, which is larger and more genetically amenable than the native host, Staphylococcus aureus. Fluorescence microscopy showed a functional fusion protein, ParM-YFP, formed straight filaments in vivo when expressed in isolation. Strikingly, however, in the presence of ParR and parC, ParM-YFP adopted a dramatically different structure, instead forming axial curved filaments. Time-lapse imaging and selective photobleaching experiments revealed that, in the presence of all components of the parMRC system, ParM-YFP filaments were dynamic in nature. Finally, molecular dissection of the parMRC operon revealed that all components of the system are essential for the generation of dynamic filaments.

Osteoid Osteoma: Experience with Laser- and Radiofrequency-Induced Ablation

International Nuclear Information System (INIS)

Gebauer, Bernhard; Tunn, Per-Ulf; Gaffke, Gunnar; Melcher, Ingo; Felix, Roland; Stroszczynski, Christian

2006-01-01

The purpose of this study was to analyze the clinical outcome of osteoid osteoma treated by thermal ablation after drill opening. A total of 17 patients and 20 procedures were included. All patients had typical clinical features (age, pain) and a typical radiograph showing a nidus. In 5 cases, additional histological specimens were acquired. After drill opening of the osteoid osteoma nidus, 12 thermal ablations were induced by laser interstitial thermal therapy (LITT) (9F Power-Laser-Set; Somatex, Germany) and 8 ablations by radiofrequency ablation (RFA) (RITA; StarBurst, USA). Initial clinical success with pain relief has been achieved in all patients after the first ablation. Three patients had an osteoid osteoma recurrence after 3, 9, and 10 months and were successfully re-treated by thermal ablation. No major complication and one minor complication (sensible defect) were recorded. Thermal ablation is a safe and minimally invasive therapy option for osteoid osteoma. Although the groups are too small for a comparative analysis, we determined no difference between laser- and radiofrequency-induced ablation in clinical outcome after ablation

Anatomical characteristics of pulmonary veins for the prediction of postoperative recurrence after radiofrequency catheter ablation of atrial fibrillation.

Directory of Open Access Journals (Sweden)

Wei Wei

Full Text Available BACKGROUND: The relationship between focal pulmonary vein potential and atrial fibrillation (AF has been confirmed. Pulmonary vein (PV isolation and circumferential pulmonary vein ablation have been the most commonly used procedures of radiofrequency ablation. However, few studies have investigated the relationship between anatomical characteristics of PV and AF recurrences after radiofrequency ablation. METHODOLOGY: For 267 AF patients treated by radiofrequency catheter ablation, the anatomic structure characteristics of pulmonary veins were assessed by multi-slice spiral computed tomography while the values of left atrial diameter (LAD were measured with transesophageal ultrasonic cardiogram. After radiofrequency catheter ablation, postoperative recurrence was evaluated during a 10-month term follow-up. PRINCIPAL FINDINGS: During follow-up, postoperative recurrence occurred in 44 patients. The mean diameters of LAD, left superior PV, right superior PV, all left PV, and all superior PV were significantly larger in patients with postoperative recurrence (Recurrence vs. Non-recurrence group; 43.9 ± 6.4 mm vs. 40.7 ± 5.6 mm; 18.4 ± 2.1 mm vs. 17.1 ± 3.1 mm; 18.2 ± 2.8 mm vs. 17.2 mm ± 3.9 mm; 16.4 ± 1.5 mm vs. 15.6 ± 2.5 mm; 18.3 ± 2.1 mm vs. 17.1 ± 3.0 mm; respectively; all P < 0.05. Multivariable survival analysis showed that the type and the course of AF, LAD, and the diameters of all superior PV were the independent risk factors for the postoperative recurrence after radiofrequency catheter ablation. CONCLUSIONS: The enlargements of all superior PV and LAD, long course of diseases, and persistent AF were the independent risk factors for the postoperative recurrence after radiofrequency catheter ablation.

Six years of evidence-based adult dissection tonsillectomy with ultrasonic scalpel, bipolar electrocautery, bipolar radiofrequency or 'cold steel' dissection.

Science.gov (United States)

Ragab, S M

2012-10-01

To conduct an adequately powered, prospective, randomised, controlled trial comparing adult dissection tonsillectomy using either ultrasonic scalpel, bipolar electrocautery, bipolar radiofrequency or 'cold steel' dissection. Three hundred patients were randomised into four tonsillectomy technique groups. The operative time, intra-operative bleeding, post-operative pain, tonsillar fossa healing, return to full diet, return to work and post-operative complications were recorded. The bipolar radiofrequency group had a shorter mean operative time. The mean intra-operative blood loss during bipolar radiofrequency tonsillectomy was significantly less compared with cold dissection and ultrasonic scalpel tonsillectomy. Pain scores were significantly higher after bipolar electrocautery tonsillectomy. Patients undergoing bipolar electrocautery tonsillectomy required significantly more days to return to full diet and work. The bipolar electrocautery group showed significantly reduced tonsillar fossa healing during the first and second post-operative weeks. In this adult series, bipolar radiofrequency tonsillectomy was superior to ultrasonic, bipolar electrocautery and cold dissection tonsillectomies. This method combines the advantages of 'hot' and 'cold' tonsillectomy.

A Retrospective Evaluation of Subsurface Monopolar Radiofrequency for Lifting of the Face, Neck, and Jawline.

Science.gov (United States)

Dendle, Julia; Wu, Douglas C; Fabi, Sabrina G; Melo, Diana; Goldman, Mitchel P

2016-11-01

Subsurface monopolar radiofrequency (SMRF) has emerged as a new method for reducing skin laxity via the controlled delivery of thermal energy below the skin using a radiofrequency probe. To evaluate the overall efficacy of the treatment and satisfaction ratings of subjects who underwent a single SMRF treatment to the face, neck, or jawline (or some combination). A retrospective, single-center study was conducted in which data were obtained via subject follow-ups at 90 and 180 days posttreatment. A total of 35 subjects, 6 men and 29 women, underwent a single SMRF treatment. Overall, 77% of subjects reported improvement, and 64% reported satisfaction with the treatment site at Day 180 posttreatment. Subsurface monopolar radiofrequency represents an effective modality to achieve skin tightening of the face, neck, and jawline. The data suggest that there is an energy delivery threshold, above which a higher percentage of subjects report satisfaction. Analysis of treatments parameters suggests an optimal treatment time and tissue temperature that should be achieved to maximize results.

Influence of the radio-frequency power on the physical and optical properties of plasma polymerized cyclohexane thin films

Energy Technology Data Exchange (ETDEWEB)

Manaa, C., E-mail: chadlia.el.manaa@gmail.com [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); Lejeune, M. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Kouki, F. [Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); Durand-Drouhin, O. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Bouchriha, H. [Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); and others

2014-06-02

We investigate in the present study the effects of the radio-frequency plasma power on the opto-electronical properties of the polymeric amorphous hydrogenated carbon thin films deposited at room temperature and different radio-frequency powers by plasma-enhanced chemical vapor deposition method using cyclohexane as precursor. A combination of U.V.–Visible and infrared transmission measurements is applied to characterize the bonding and electronic properties of these films. Some film properties namely surface roughness, contact angle, surface energy, and optical properties are found to be significantly influenced by the radio-frequency power. The changes in these properties are analyzed within the microstructural modifications occurring during growth. - Highlights: • Effects of the radio-frequency power on the optoelectronic properties of thin films • Elaboration of plasma polymerized thin films using cyclohexane as precursor gas • The use of U.V.–Visible-infrared transmission, and optical gap • Study of the surface topography of the films by using Atomic Force microscopy • The use of a capacitively coupled plasma enhanced chemical vapor deposition method.

Influence of the radio-frequency power on the physical and optical properties of plasma polymerized cyclohexane thin films

International Nuclear Information System (INIS)

Manaa, C.; Lejeune, M.; Kouki, F.; Durand-Drouhin, O.; Bouchriha, H.

2014-01-01

We investigate in the present study the effects of the radio-frequency plasma power on the opto-electronical properties of the polymeric amorphous hydrogenated carbon thin films deposited at room temperature and different radio-frequency powers by plasma-enhanced chemical vapor deposition method using cyclohexane as precursor. A combination of U.V.–Visible and infrared transmission measurements is applied to characterize the bonding and electronic properties of these films. Some film properties namely surface roughness, contact angle, surface energy, and optical properties are found to be significantly influenced by the radio-frequency power. The changes in these properties are analyzed within the microstructural modifications occurring during growth. - Highlights: • Effects of the radio-frequency power on the optoelectronic properties of thin films • Elaboration of plasma polymerized thin films using cyclohexane as precursor gas • The use of U.V.–Visible-infrared transmission, and optical gap • Study of the surface topography of the films by using Atomic Force microscopy • The use of a capacitively coupled plasma enhanced chemical vapor deposition method

First (18)F-labeled ligand for PET imaging of uPAR

DEFF Research Database (Denmark)

Persson, Morten; Liu, Hongguang; Madsen, Jacob

2013-01-01

Urokinase-type plasminogen activator receptor (uPAR) is overexpressed in human prostate cancer and uPAR has been found to be associated with metastatic disease and poor prognosis. AE105 is a small linear peptide with high binding affinity to uPAR. We synthesized an N-terminal NOTA......-conjugated version (NOTA-AE105) for development of the first (18)F-labeled uPAR positron-emission-tomography PET ligand using the Al(18)F radiolabeling method. In this study, the potential of (18)F-AlF-NOTA-AE105 to specifically target uPAR-positive prostate tumors was investigated....

Radiofrequency therapy in back pain and complex regional pain syndrome (CRPS

Directory of Open Access Journals (Sweden)

Norina Bergamin

2011-01-01

Full Text Available Percutaneous radiofrequency procedures are frequently used in the management of chronic pain. Continuous radiofrequency (CRF has been established as a safe and effective treatment for pain originating from facet and sacroiliac joints by way of co-agulation of their nerve supply. Different methods have been proposed to account for the complex nerve supply of the sacroiliac joint. Due to its neurodestructive property, CRF was limited to the treatment of neuropathic pain. When applied to the dorsal root ganglion (DRG for spinal pain or to the sympathetic ganglia in treatment of CRPS, heat related side effects have been reported. With the development of pulsed radiofrequency (PRF, a less destructive alternative to CRF became available, that is more suitable to treat neuropathic pain. PRF was adopted in the treatment of several pain conditions with different success. The results with PRF adjacent to the DRG are promising, whereas for facet and sacroiliac joint pain PRF could not yet be proven equally effective as CRF. As for PRF in CRPS there is almost no evidence available. The potential of PRF seems to lie in those areas where CRF is of limited value. Con-versely, it is questionable if PRF will ever be equally effective in indications, where CRF is already well established. Despite its active use in clinical practice, PRF is not validated yet nor is its mode of action. The literature in both cases is accumulating but further studies are urgently needed.

Plasma heating by radiofrequency in the electron cyclotron resonance (ECR)

International Nuclear Information System (INIS)

Cunha Raposo, C. da; Aihara, S.; Universidade Estadual de Campinas

1982-01-01

The characteristics of the experimental set-up mounted in the Physical Institute of UFF (Brazil) to produce the gas ionization by radio-frequency are shown and its behaviour when confined by a mirror-geometry magnetic field is studied. The diagnostic is made by a langmuir probe and a prisme spectrogaph is used in order to verify the nature of the ionized helium gas and the degree of purity through its spectral lines. The argon ionization by R.f. is produced in the 'LISA' machine obtain a plasma column of approximatelly 60 cm length and with the Langmuir probe the study of the profile distribution of the plasma parameters such as: electron temperature and density and floating potencial in function of the magnetic field variation is made. The main focus is given to the fundamental electron cyclotron resonance (ECR). A new expression on the ion saturation current (I sub(is)) produced by radiofrequency is developed. (L.C.) [pt

Radio-frequency quadrupole linear accelerator

International Nuclear Information System (INIS)

Wangler, T.P.; Stokes, R.H.

1980-01-01

The radio-frequency quadrupole (RFQ) is a new linear accelerator concept in which rf electric fields are used to focus, bunch, and accelerate the beam. Because the RFQ can provide strong focusing at low velocities, it can capture a high-current dc ion beam from a low-voltage source and accelerate it to an energy of 1 MeV/nucleon within a distance of a few meters. A recent experimental test at the Los Alamos Scientific Laboratory (LASL) has confirmed the expected performance of this structure and has stimulated interest in a wide variety of applications. The general properties of the RFQ are reviewed and examples of applications of this new accelerator are presented

Narrative Identities and the Plebiscite in Pará: An Analysis of the Front Pages for O Liberal and Diário do Pará

Directory of Open Access Journals (Sweden)

Alda Cristina Silva da Costa

2017-05-01

Full Text Available On December 11, 2011, a plebiscite was held in Pará proposing to create two separatist states, Carajás and Tapajós, out of the state of Pará. The public voted against both projects. This article analyzes the narrative identities found on the front pages of O Liberal and Diário do Pará newspapers about the plebiscite in Pará. Depth Hermeneutics (DH, as proposed by Thompson (2011, was used as the methodological reference. DH emphasizes the object of analysis as a meaningful symbolic construction requiring interpretation. Narrative analysis, as proposed by Motta (2007, was the main research technique used to highlight the movement of construction of journalistic (discursive characters. The narrative identities built by the two newspapers showed that both were against the creation of the new states, but for very different reasons. The flag of Pará was the main object used to induce the idea of unity. Em 11 de dezembro de 2011, o plebiscito no Pará propôs a criação dos estados de Carajás e de Tapajós a partir da divisão do estado do Pará. O resultado da consulta pública foi negativo aos dois projetos. O artigo analisa as identidades narrativas constituídas pelas primeiras páginas dos jornais O Liberal e Diário do Pará sobre o plebiscito no Pará. Utilizou-se como referencial metodológico a Hermenêutica em Profundidade (HP, proposta por Thompson (2011. A HP evidencia o fato de que o objeto de análise é uma construção simbólica significativa, que exige uma interpretação. Como principal técnica de pesquisa, a análise narrativa, proposta por Motta (2007, com ênfase no movimento de construção de personagens jornalísticas (discursivas. As identidades narrativas construídas pelos dois jornais indicaram que ambos eram contrários à criação dos novos estados, porém por motivos divergentes. A bandeira do Pará foi o principal elemento utilizado para evocar a ideia de unidade. En 11 de diciembre de 2011, el plebiscito en

Effects of 1.84 GHz radio-frequency electromagnetic field on sperm ...

African Journals Online (AJOL)

sunny t

Key words: 1.84 GHz, radio-frequency electromagnetic field (RF-EMF), epididymis, ... Author(s) agree that this article remains permanently open access under the terms of the ..... mouse testis after the long-term administration of nickel in feed.

Therapeutic effect of radiofrequency ablation on children with supraventricular tachycardia and the risk factors for postoperative recurrence.

Science.gov (United States)

Li, Chunli; Jia, Libo; Wang, Zhenzhou; Niu, Ling; An, Xinjiang

2018-05-01

The present study investigated the therapeutic effect of radiofrequency ablation on children with supraventricular tachycardia (SVT), and explored the risk factors for postoperative recurrence. A total of 312 patients with pediatric SVT were selected in the Affiliated Children's Hospital of Xuzhou Medical University from April, 2011 to March, 2017. All the patients were subjected to radiofrequency ablation, and clinical data were retrospectively analyzed. Tilt table test was performed before and after treatment, and heart rate, systolic and diastolic blood pressure before and after treatment were compared. Plasma levels of D-dimer (D-D), platelet α-granule membrane protein (GMP-140) and thrombin-antithrombin III complex (TAT) were detected by enzyme-linked immunosorbent assay before treatment, immediately after radiofrequency oblation, and at 1, 3 and 7 days after treatment. Treatment outcomes were compared between the atrioventricular reentrant tachycardia (AVRT) and atrioventricular nodal reentrant tachycardia (AVNRT) groups. Risk factors for postoperative recurrence were analyzed. Supine position heart rate after treatment was not significantly different from that before treatment (P>0.05), while the upright position heart rate was significantly increased after treatment (P0.05). No significant difference in radiofrequency ablation rate, recurrence rate and incidence of complications were found between the AVRT and AVNRT groups (P>0.05). After radiofrequency, the levels of D-D, GMP-140 and TAT ablation showed an upward trend, but decreased at day 7 to reach preoperative levels. Logistic regression analysis revealed that residual slow pathway (OR=6.718, P=0.005) and inaccurate targeting (OR=2.815, P=0.007) were independent risk factors for postoperative recurrence (Pradiofrequency ablation can damage the cardiac vagal nerve, resulting in an increase in the heart rate after ablation during the course of the tilt table test and changed hemagglutination state

Limnological database for Par Pond: 1959 to 1980

International Nuclear Information System (INIS)

Tilly, L.J.

1981-03-01

A limnological database for Par Pond, a cooling reservoir for hot reactor effluent water at the Savannah River Plant, is described. The data are derived from a combination of research and monitoring efforts on Par Pond since 1959. The approximately 24,000-byte database provides water quality, primary productivity, and flow data from a number of different stations, depths, and times during the 22-year history of the Par Pond impoundment. The data have been organized to permit an interpretation of the effects of twenty years of cooling system operations on the structure and function of an aquatic ecosystem

Radiofrequency catheter ablation: A study concerning electrode configuration, lesion size and potential complications

International Nuclear Information System (INIS)

Anfinsen, Ole-Gunnar

1999-01-01

The study was performed to evaluate different methods of increasing the lesion size in radiofrequency catheter ablation, which is an important issue as the clinical indications for RF ablation are extended. The safety aspects of RF ablation are also studied, both with standard catheters and with experimental ones. The studies have been performed in vitro, in an animal model and in patients. The results are presented in 5 papers with titles of: 1) 'Radiofrequency catheter ablation of procine right atrium: Increased lesion size with bipolar two-catheter technique compared to unipolar application in vitro and in vivo. 2) Bipolar radiofrequency catheter ablation creates confluent lesions at a larger interelectrode spacing than does unipolar ablation from two electrodes in porcine heart. 3) Temperature-controlled radiofrequency catheter ablation with a 10 mm tip electrode creates larger lesions without charring in the porcine heart. 4) Radiofrequency catheter ablation in vitro: The difference between tissue and catheter tip temperature depends on location of the temperature sensor. 5) The activation of platelet function, coagulation and fibrinolysis during radiofrequency catheter ablation in heparin zed patients. The main conclusions are: 1) Large RF lesions may be created either by using larger electrodes and more power in the unipolar mode, or by changing the electrode configuration and thereby the geometry of the electrical field during RF current delivery. Both the 10 mm unipolar, the dielectrode and the bipolar mode showed feasible in porcine IVC-TV isthmus and right atrial free wall ablations, but the gain in lesion length was most pronounced in the bipolar mode. 2) Crater formation and intramural haemorrhages may complicate RF ablation using high current density in the right atrial free wall. In our study this was observed with 10 mm unipolar and bipolar two-catheter ablation. Phrenic nerve injury and lesions of the adjacent pulmonary tissue are risks related to

Radiofrequency catheter ablation: A study concerning electrode configuration, lesion size and potential complications

Energy Technology Data Exchange (ETDEWEB)

Anfinsen, Ole-Gunnar

1999-07-01

The study was performed to evaluate different methods of increasing the lesion size in radiofrequency catheter ablation, which is an important issue as the clinical indications for RF ablation are extended. The safety aspects of RF ablation are also studied, both with standard catheters and with experimental ones. The studies have been performed in vitro, in an animal model and in patients. The results are presented in 5 papers with titles of: 1) 'Radiofrequency catheter ablation of procine right atrium: Increased lesion size with bipolar two-catheter technique compared to unipolar application in vitro and in vivo. 2) Bipolar radiofrequency catheter ablation creates confluent lesions at a larger interelectrode spacing than does unipolar ablation from two electrodes in porcine heart. 3) Temperature-controlled radiofrequency catheter ablation with a 10 mm tip electrode creates larger lesions without charring in the porcine heart. 4) Radiofrequency catheter ablation in vitro: The difference between tissue and catheter tip temperature depends on location of the temperature sensor. 5) The activation of platelet function, coagulation and fibrinolysis during radiofrequency catheter ablation in heparin zed patients. The main conclusions are: 1) Large RF lesions may be created either by using larger electrodes and more power in the unipolar mode, or by changing the electrode configuration and thereby the geometry of the electrical field during RF current delivery. Both the 10 mm unipolar, the dielectrode and the bipolar mode showed feasible in porcine IVC-TV isthmus and right atrial free wall ablations, but the gain in lesion length was most pronounced in the bipolar mode. 2) Crater formation and intramural haemorrhages may complicate RF ablation using high current density in the right atrial free wall. In our study this was observed with 10 mm unipolar and bipolar two-catheter ablation. Phrenic nerve injury and lesions of the adjacent pulmonary tissue are risks

Pregnancy outcomes after paternal radiofrequency field exposure aboard fast patrol boats.

Science.gov (United States)

Baste, Valborg; Moen, Bente E; Oftedal, Gunnhild; Strand, Leif Age; Bjørge, Line; Mild, Kjell Hansson

2012-04-01

To investigate adverse reproductive outcomes among male employees in the Royal Norwegian Navy exposed to radiofrequency electromagnetic fields aboard fast patrol boats. Cohort study of Royal Norwegian Navy servicemen linked to the Medical Birth Registry of Norway, including singleton offspring born between 1967 and 2008 (n = 37,920). Exposure during the last 3 months before conception (acute) and exposure more than 3 months before conception (nonacute) were analyzed. Perinatal mortality and preeclampsia increased after service aboard fast patrol boats during an acute period and also after increased estimated radiofrequency exposure during an acute period, compared with service aboard other vessels. No associations were found between nonacute exposure and any of the reproductive outcomes. Paternal work aboard fast patrol boats during an acute period was associated with perinatal mortality and preeclampsia, but the cause is not clear.

Soluble urokinase plasminogen activator receptor (suPAR) in acute care

DEFF Research Database (Denmark)

Rasmussen, Line Jee Hartmann; Ladelund, Steen; Haupt, Thomas Huneck

2016-01-01

for age, sex, Charlson score and C reactive protein. Area under the curve for receiver operating characteristics curve analysis of suPAR for 30-day mortality was 0.84 (95% CI 0.81 to 0.86). Furthermore, in the entire cohort, women had slightly higher suPAR compared with men, and suPAR was associated...

Radiofrequency thermal ablation of a metastatic lung nodule

Energy Technology Data Exchange (ETDEWEB)

Highland, Adrian M. [Department of Clinical Radiology, Hull Royal Infirmary, Anlaby Road, Hull, HU3 2JZ (United Kingdom); Mack, Paul [Diana Princess of Wales Hospital, Scartho Road, Grimsby, DN33 2BA (United Kingdom); Breen, David J. [Department of Radiology, Southampton University Hospitals, Tremona Road, Southampton, SO16 6YD (United Kingdom)

2002-07-01

Pulmonary metastases are a common finding in patients with colonic adenocarcinoma. We report the treatment of a metastatic lung nodule with radiofrequency (RF) ablation under CT guidance. This case illustrates the use of RF ablation in a patient in whom surgical resection was no longer possible and where chemotherapy was unlikely to produce benefit. This technique may offer a viable method of cytoreduction when other treatments have not succeeded. (orig.)

Radiofrequency thermal ablation of a metastatic lung nodule

International Nuclear Information System (INIS)

Highland, Adrian M.; Mack, Paul; Breen, David J.

2002-01-01

Pulmonary metastases are a common finding in patients with colonic adenocarcinoma. We report the treatment of a metastatic lung nodule with radiofrequency (RF) ablation under CT guidance. This case illustrates the use of RF ablation in a patient in whom surgical resection was no longer possible and where chemotherapy was unlikely to produce benefit. This technique may offer a viable method of cytoreduction when other treatments have not succeeded. (orig.)

Diaphragmatic Hernia After Radiofrequency Ablation for Hepatocellular Carcinoma

International Nuclear Information System (INIS)

Yamagami, Takuji; Yoshimatsu, Rika; Matsushima, Shigenori; Tanaka, Osamu; Miura, Hiroshi; Nishimura, Tsunehiko

2011-01-01

We describe a 71-year-old woman with a hepatocellular carcinoma who underwent percutaneous radiofrequency ablation (RF) with a single internally cooled electrode under computed tomography (CT) fluoroscopic guidance. Nine months after the procedure, CT images showed herniation of the large intestine into the right pleural cavity. To our knowledge this complication of RF performed with a single internally cooled electrode under CT guidance has not been previously reported.

Diverse radiofrequency sensitivity and radiofrequency effects of mobile or cordless phone near fields exposure in Drosophila melanogaster.

Science.gov (United States)

Geronikolou, Styliani; Zimeras, Stelios; Davos, Constantinos H; Michalopoulos, Ioannis; Tsitomeneas, Stephanos

2014-01-01

The impact of electromagnetic fields on health is of increasing scientific interest. The aim of this study was to examine how the Drosophila melanogaster animal model is affected when exposed to portable or mobile phone fields. Two experiments have been designed and performed in the same laboratory conditions. Insect cultures were exposed to the near field of a 2G mobile phone (the GSM 2G networks support and complement in parallel the 3G wide band or in other words the transmission of information via voice signals is served by the 2G technology in both mobile phones generations) and a 1880 MHz cordless phone both digitally modulated by human voice. Comparison with advanced statistics of the egg laying of the second generation exposed and non-exposed cultures showed limited statistical significance for the cordless phone exposed culture and statistical significance for the 900 MHz exposed insects. We calculated by physics, simulated and illustrated in three dimensional figures the calculated near fields of radiation inside the experimenting vials and their difference. Comparison of the power of the two fields showed that the difference between them becomes null when the experimental cylinder radius and the height of the antenna increase. Our results suggest a possible radiofrequency sensitivity difference in insects which may be due to the distance from the antenna or to unexplored intimate factors. Comparing the near fields of the two frequencies bands, we see similar not identical geometry in length and height from the antenna and that lower frequencies tend to drive to increased radiofrequency effects.

Radiofrequency-assisted Liposuction for Arm Contouring: Technique under Local Anesthesia

Directory of Open Access Journals (Sweden)

Spero Theodorou, MD

2013-08-01

Conclusions: In appropriately selected patients, RFAL arm contouring under local anesthesia represents an alternative procedure with acceptably low morbidity and high patient satisfaction. To achieve consistent results while minimizing complications, consideration to anatomic details, infiltration of the local anesthetic, and application of the radiofrequency energy must be given.

Radiofrequency ablation of liver tumors by using monopolar perfusion electrode:an analysis of therapeutic results

International Nuclear Information System (INIS)

Luo Rongguang; Gu Yangkui; Gao Fei; Zhang Liang; Zhao Ming; Fan Weijun; Wu Peihong; Huang Jinhua

2010-01-01

Objective: To investigate the clinical value of CT-guided radiofrequency ablation by using monopolar perfusion electrode in treating liver tumors. Methods: From January 2008 to December 2008, 24 patients with 37 lesions of liver tumors were treated with radiofrequency ablation by using monopolar perfusion electrode (RITA UniBlate). Of the 24 patients,solitary lesion was seen in 14, two lesions in 7 and three lesions in 3. Among 37 lesions,the maximum diameter of the lesion ≤ 3 cm, 3.1∼5 cm and > 5 cm was determined in 24, 8 and 5, respectively. The changes of the tumor size and the AFP level were observed. A follow-up lasting for 12 months was conducted. Results: After radiofrequency ablation twenty-two lesions (22/37, 59.5%) were completely ablated, of which nineteen tumors (19/24, 79.2%) were smaller than 3 cm in diameter, two tumors (2 / 8, 25%) had a diameter between 3.1 cm and 5 cm, one tumor (1 / 5, 20%) was larger than 5 cm. Fifteen tumors (15 / 37, 40.5%) were not completely ablated. During the follow-up period of 12 months, fifteen patients (15 / 24, 62.5%) remained alive and nine patients died, of whom the survival time was less than 6 months in six and was 6 -12 months in 4. After radiofrequency ablation, the AFP level decreased to normal level in 5 patients (5 / 10, 50%), and mild decrease of AFP, but still higher than normal,was seen in 3 patients (3 / 10, 30%). Of 10 patients who had a positive AFP test, 2 (2 / 10, 10%) showed a continuous rise in the AFP level. After radiofrequency ablation, one patient developed a minor hepatic subcapsular bleeding,and all patients complained of different degrees of fever and upper abdominal pain. Conclusion: CT-guided radiofrequency ablation by using monopolar perfusion electrode is a minimally-invasive technique with reliable short-term results and fewer complications. Therefore, it is a safe and effective local treatment for liver cancer. For tumors smaller than 3 cm in diameter complete ablation can be

Cervical radiofrequency neurotomy reduces central hyperexcitability and improves neck movement in individuals with chronic whiplash.

Science.gov (United States)

Smith, Ashley Dean; Jull, Gwendolen; Schneider, Geoff; Frizzell, Bevan; Hooper, Robert Allen; Sterling, Michele

2014-01-01

This study aims to determine if cervical medial branch radiofrequency neurotomy reduces psychophysical indicators of augmented central pain processing and improves motor function in individuals with chronic whiplash symptoms. Prospective observational study of consecutive patients with healthy control comparison. Tertiary spinal intervention centre in Calgary, Alberta, Canada. Fifty-three individuals with chronic whiplash associated disorder symptoms (Grade 2); 30 healthy controls. Measures were made at four time points: two prior to radiofrequency neurotomy, and 1- and 3-months post-radiofrequency neurotomy. Measures included: comprehensive quantitative sensory testing (including brachial plexus provocation test), nociceptive flexion reflex, and motor function (cervical range of movement, superficial neck flexor activity during the craniocervical flexion test). Self-report pain and disability measures were also collected. One-way repeated measures analysis of variance and Friedman's tests were performed to investigate the effect of time on the earlier measures. Differences between the whiplash and healthy control groups were investigated with two-tailed independent samples t-test or Mann-Whitney tests. Following cervical radiofrequency neurotomy, there were significant early (within 1 month) and sustained (3 months) improvements in pain, disability, local and widespread hyperalgesia to pressure and thermal stimuli, nociceptive flexor reflex threshold, and brachial plexus provocation test responses as well as increased neck range of motion (all P  0.13) was measured. Attenuation of psychophysical measures of augmented central pain processing and improved cervical movement imply that these processes are maintained by peripheral nociceptive input. Wiley Periodicals, Inc.

Three Cycles of Radiofrequency Ablation Are More Efficacious Than Two in the Management of Morton's Neuroma.

Science.gov (United States)

Brooks, David; Parr, Adam; Bryceson, William

2018-04-01

Morton's neuroma is a common cause of forefoot pain. Outcomes of conservative therapy are mixed and many patients undergo operative intervention. Radiofrequency ablation has recently gained favor as a treatment option, although the optimal regime is unknown. This study investigates the effectiveness of 2 versus 3 cycles of radiofrequency ablation for the treatment of Morton's neuroma. We surveyed a cohort of patients with Morton's neuroma who had progressed to radiofrequency ablation after failed conservative treatment. Patients received either 2 or 3 cycles of radiofrequency ablation by a single surgeon. We assessed patients based on their change in numerical pain rating scale, symptom improvement, complications, and progression to surgical excision through a series of telephone interviews. Outcomes between the 2 treatment arms were compared by parametric tests. Twenty-eight patients were included in the study. Eighteen patients with 21 neuromas received 2 cycles and 10 patients with 11 neuromas received 3 cycles. Mean time of follow-up was 12.9 months. Overall, 88% of patients were either very or moderately satisfied with their outcome. In patients who received 2 cycles mean numerical pain scores decreased from 7.9 ± 1.1 to 3.4 ± 2.4 postprocedure. Three patients progressed to operative excision. In patients who received 3 cycles, numerical pain scores decreased from 8.0 ± 1.0 to 1.5 ± 2.0 postprocedure. One patient progressed to operative excision. Patients who received 3 cycles had reduced medium-term pain postoperatively compared with 2 cycles (3.4 ± 2.4 vs 1.5 ± 2.0, P = .011). Radiofrequency ablation provides a high rate of patient satisfaction in the treatment of Morton's neuroma with few side effects. It appears that 3 cycles may be superior to 2 cycles but a randomized controlled trial will be required to confirm these results. Intervention, Level III: Comparative study without concurrent controls.

Temperature responsive porous silicon nanoparticles for cancer therapy - spatiotemporal triggering through infrared and radiofrequency electromagnetic heating.

Science.gov (United States)

Tamarov, Konstantin; Xu, Wujun; Osminkina, Liubov; Zinovyev, Sergey; Soininen, Pasi; Kudryavtsev, Andrey; Gongalsky, Maxim; Gaydarova, Azha; Närvänen, Ale; Timoshenko, Victor; Lehto, Vesa-Pekka

2016-11-10

One critical functionality of the carrier system utilized in targeted drug delivery is its ability to trigger the release of the therapeutic cargo once the carrier has reached its target. External triggering is an alluring approach as it can be applied in a precise spatiotemporal manner. In the present study, we achieved external triggering through the porous silicon (PSi) nanoparticles (NPs) by providing a pulse of infrared or radiofrequency radiation. The NPs were grafted with a temperature responsive polymer whose critical temperature was tailored to be slightly above 37°C. The polymer coating improved the biocompatibility of the NPs significantly in comparison with their uncoated counterparts. Radiation induced a rapid temperature rise, which resulted in the collapse of the polymer chains facilitating the cargo release. Both infrared and radiofrequency radiation were able to efficiently trigger the release of the encapsulated drug in vitro and induce significant cell death in comparison to the control groups. Radiofrequency radiation was found to be more efficient in vitro, and the treatment efficacy was verified in vivo in a lung carcinoma (3LL) mice model. After a single intratumoral administration of the carrier system combined with radiofrequency radiation, there was clear suppression of the growth of the carcinoma and a prolongation of the survival time of the animals. The temperature responsive (TR) polymer grafted on the surface of porous silicon nanoparticles (PSi NPs) changes its conformation in response to the heating induced by infrared or radiofrequency radiation. The conformation change allows the loaded doxorubicin to escape from the pores, achieving controlled drug release from TR PSi NPs, which displayed efficacy against malignant cells both in vitro and in vivo. Copyright © 2016 Elsevier B.V. All rights reserved.

Accurate Depth of Radiofrequency-Induced Lesions in Renal Sympathetic Denervation Based on a Fine Histological Sectioning Approach in a Porcine Model.

Science.gov (United States)

Sakaoka, Atsushi; Terao, Hisako; Nakamura, Shintaro; Hagiwara, Hitomi; Furukawa, Toshihito; Matsumura, Kiyoshi; Sakakura, Kenichi

2018-02-01

Ablation lesion depth caused by radiofrequency-based renal denervation (RDN) was limited to radiofrequency-RDN cannot ablate a substantial percentage of renal sympathetic nerves. We aimed to define the true lesion depth achieved with radiofrequency-RDN using a fine sectioning method and to investigate biophysical parameters that could predict lesion depth. Radiofrequency was delivered to 87 sites in 14 renal arteries from 9 farm pigs at various ablation settings: 2, 4, 6, and 9 W for 60 seconds and 6 W for 120 seconds. Electric impedance and electrode temperature were recorded during ablation. At 7 days, 2470 histological sections were obtained from the treated arteries. Maximum lesion depth increased at 2 to 6 W, peaking at 6.53 (95% confidence interval, 4.27-8.78) mm under the 6 W/60 s condition. It was not augmented by greater power (9 W) or longer duration (120 seconds). There were statistically significant tendencies at 6 and 9 W, with higher injury scores in the media, nerves, arterioles, and fat. Maximum lesion depth was positively correlated with impedance reduction and peak electrode temperature (Pearson correlation coefficients were 0.59 and 0.53, respectively). Lesion depth was 6.5 mm for radiofrequency-RDN at 6 W/60 s. The impedance reduction and peak electrode temperature during ablation were closely associated with lesion depth. Hence, these biophysical parameters could provide prompt feedback during radiofrequency-RDN procedures in the clinical setting. © 2018 The Authors.

Results of Cryoenergy and Radiofrequency-Based Catheter Ablation for Treating Ventricular Arrhythmias Arising From the Papillary Muscles of the Left Ventricle, Guided by Intracardiac Echocardiography and Image Integration.

Science.gov (United States)

Rivera, Santiago; Ricapito, Maria de la Paz; Tomas, Leandro; Parodi, Josefina; Bardera Molina, Guillermo; Banega, Rodrigo; Bueti, Pablo; Orosco, Agustin; Reinoso, Marcelo; Caro, Milagros; Belardi, Diego; Albina, Gaston; Giniger, Alberto; Scazzuso, Fernando

2016-04-01

Catheter radiofrequency ablation of ventricular arrhythmias (VAs) arising from the left ventricle's papillary muscles has been associated with inconsistent results. The use of cryoenergy versus radiofrequency has not been compared yet. This study compares outcomes and complications of catheter ablation of VA from the papillary muscles of the left ventricle with either cryoenergy or radiofrequency. Twenty-one patients (40±12 years old; 47% males; median ejection fraction 59±7.3%) with drug refractory premature ventricular contractions or ventricular tachycardia underwent catheter cryoablation or radiofrequency ablation. VAs were localized using 3-dimensional mapping, multidetector computed tomography, and intracardiac echocardiography, with arrhythmia foci being mapped at either the anterolateral papillary muscle or posteromedial papillary muscles of the left ventricle. Focal ablation was performed using an 8-mm cryoablation catheter or a 4-mm open-irrigated radiofrequency catheter, via transmitral approach. Acute success rate was 100% for cryoenergy (n=12) and 78% for radiofrequency (n=9; P=0.08). Catheter stability was achieved in all patients (100%) treated with cryoenergy, and only in 2 (25%) patients treated with radiofrequency (P=0.001). Incidence of multiple VA morphologies was observed in 7 patients treated with radiofrequency (77.7%), whereas none was observed in those treated with cryoenergy (P=0.001). VA recurrence at 6 months follow-up was 0% for cryoablation and 44% for radiofrequency (P=0.03). Cryoablation was associated with higher success rates and lower recurrence rates than radiofrequency catheter ablation, better catheter stability, and lesser incidence of polymorphic arrhythmias. © 2016 American Heart Association, Inc.

Intact and cleaved uPAR forms: diagnostic and prognostic value in cancer

DEFF Research Database (Denmark)

Rasch, M.G.; Lund, I.K.; Hoyer-Hansen, G.

2008-01-01

identified in tissue and body fluids. It is well-established, that the total amount of all uPAR forms is a strong prognostic marker in different types of cancer. Using immunoassays, measuring the individual uPAR forms, has revealed that the cleaved uPAR forms are even stronger prognostic markers and have...... diagnostic utility. This review will focus on the mechanism of uPAR cleavage and the functional consequences, as well as the clinical applicability of cleaved uPAR forms Udgivelsesdato: 2008...

Development of the method of aggregation to determine the current storage area using computer vision and radiofrequency identification

Science.gov (United States)

Astafiev, A.; Orlov, A.; Privezencev, D.

2018-01-01

The article is devoted to the development of technology and software for the construction of positioning and control systems in industrial plants based on aggregation to determine the current storage area using computer vision and radiofrequency identification. It describes the developed of the project of hardware for industrial products positioning system in the territory of a plant on the basis of radio-frequency grid. It describes the development of the project of hardware for industrial products positioning system in the plant on the basis of computer vision methods. It describes the development of the method of aggregation to determine the current storage area using computer vision and radiofrequency identification. Experimental studies in laboratory and production conditions have been conducted and described in the article.

Ion transmission in a linear radiofrequency spectrometer

International Nuclear Information System (INIS)

Gomet, J.-C.

1975-01-01

A linear radiofrequency spectrometer is used for the purpose of experimental determination of the absolute ionization cross sections of various ions obtained by electron impact on polyatomic molecules. The transmission of the apparatus is studied: it does not only depend on the mass resolution of the spectrometer, but also on the nature of ions. It is affected by charge transfers, especially for the parent ions. An empiric way of correction of the apparatus function is given which allows the use at 10 -6 Torr [fr

A Bipolar Spindle of Antiparallel ParM Filaments Drives Bacterial Plasmid Segregation

DEFF Research Database (Denmark)

Gayathri, P; Fujii, T; Møller-Jensen, Jakob

2012-01-01

the spindle between ParRC complexes on sister plasmids. Using a combination of structural work and total internal reflection fluorescence microscopy, we show that ParRC bound and could accelerate growth at only one end of polar ParM filaments, mechanistically resembling eukaryotic formins. The architecture...... of ParM filaments enabled two ParRC-bound filaments to associate in an antiparallel orientation, forming a bipolar spindle. The spindle elongated as a bundle of at least two antiparallel filaments, thereby pushing two plasmid clusters toward the poles....

Adverse effects of radiofrequency ablation of liver tumours in the Netherlands

NARCIS (Netherlands)

Jansen, M. C.; van Duijnhoven, F. H.; van Hillegersberg, R.; Rijken, A.; van Coevorden, F.; van der Sijp, J.; Prevoo, W.; van Gulik, T. M.

2005-01-01

Background: Radiofrequency ablation (RFA) is a new treatment for liver tumours. Complications encountered after RFA in the Netherlands were evaluated in the present study. Methods: Between June 1999 and November 2003 patients undergoing RFA of irresectable liver tumours in eight medical centres were

Radiofrequency ablation of fast ventricular tachycardia causing an ICD storm in an infant with hypertrophic cardiomyopathy.

Science.gov (United States)

Ergul, Yakup; Ozyilmaz, Isa; Bilici, Meki; Ozturk, Erkut; Haydin, Sertaç; Guzeltas, Alper

2018-04-01

An implantable cardioverter defibrillator (ICD) storm involves very frequent arrhythmia episodes and ICD shocks, and it is associated with poor short-term and long-term prognosis. Radiofrequency catheter ablation can be used as an effective rescue treatment for patients with an ICD storm. To our knowledge, this is the first report of an infant with hypertrophic cardiomyopathy presenting with an ICD storm and undergoing successful radiofrequency catheter ablation salvage treatment for the fast left posterior fascicular ventricular tachycardia. © 2017 Wiley Periodicals, Inc.

PAR-2 expression in the gingival crevicular fluid reflects chronic periodontitis severity

Directory of Open Access Journals (Sweden)

Henrique FUKUSHIMA

Full Text Available Abstract Recent studies investigating protease-activated receptor type 2 (PAR-2 suggest an association between the receptor and periodontal inflammation. It is known that gingipain, a bacterial protease secreted by the important periodontopathogen Porphyromonas gingivalis can activate PAR-2. Previous studies by our group found that PAR-2 is overexpressed in the gingival crevicular fluid (GCF of patients with moderate chronic periodontitis (MP. The present study aimed at evaluating whether PAR-2 expression is associated with chronic periodontitis severity. GCF samples and clinical parameters, including plaque and bleeding on probing indices, probing pocket depth and clinical attachment level, were collected from the control group (n = 19 at baseline, and from MP patients (n = 19 and severe chronic periodontitis (SP (n = 19 patients before and 6 weeks after periodontal non-surgical treatment. PAR-2 and gingipain messenger RNA (mRNA in the GCF of 4 periodontal sites per patient were evaluated by Reverse Transcription Polymerase Chain Reaction (RT-qPCR. PAR-2 and gingipain expressions were greater in periodontitis patients than in control group patients. In addition, the SP group presented increased PAR-2 and gingipain mRNA levels, compared with the MP group. Furthermore, periodontal treatment significantly reduced (p <0.05 PAR-2 expression in patients with periodontitis. In conclusion, PAR-2 is associated with chronic periodontitis severity and with gingipain levels in the periodontal pocket, thus suggesting that PAR-2 expression in the GCF reflects the severity of destruction during periodontal infection.

Structures of actin-like ParM filaments show architecture of plasmid-segregating spindles.

Science.gov (United States)

Bharat, Tanmay A M; Murshudov, Garib N; Sachse, Carsten; Löwe, Jan

2015-07-02

Active segregation of Escherichia coli low-copy-number plasmid R1 involves formation of a bipolar spindle made of left-handed double-helical actin-like ParM filaments. ParR links the filaments with centromeric parC plasmid DNA, while facilitating the addition of subunits to ParM filaments. Growing ParMRC spindles push sister plasmids to the cell poles. Here, using modern electron cryomicroscopy methods, we investigate the structures and arrangements of ParM filaments in vitro and in cells, revealing at near-atomic resolution how subunits and filaments come together to produce the simplest known mitotic machinery. To understand the mechanism of dynamic instability, we determine structures of ParM filaments in different nucleotide states. The structure of filaments bound to the ATP analogue AMPPNP is determined at 4.3 Å resolution and refined. The ParM filament structure shows strong longitudinal interfaces and weaker lateral interactions. Also using electron cryomicroscopy, we reconstruct ParM doublets forming antiparallel spindles. Finally, with whole-cell electron cryotomography, we show that doublets are abundant in bacterial cells containing low-copy-number plasmids with the ParMRC locus, leading to an asynchronous model of R1 plasmid segregation.

Anthropogenic radiofrequency electromagnetic fields as an emerging threat to wildlife orientation.

Science.gov (United States)

Balmori, Alfonso

2015-06-15

The rate of scientific activity regarding the effects of anthropogenic electromagnetic radiation in the radiofrequency (RF) range on animals and plants has been small despite the fact that this topic is relevant to the fields of experimental biology, ecology and conservation due to its remarkable expansion over the past 20 years. Current evidence indicates that exposure at levels that are found in the environment (in urban areas and near base stations) may particularly alter the receptor organs to orient in the magnetic field of the earth. These results could have important implications for migratory birds and insects, especially in urban areas, but could also apply to birds and insects in natural and protected areas where there are powerful base station emitters of radiofrequencies. Therefore, more research on the effects of electromagnetic radiation in nature is needed to investigate this emerging threat. Copyright © 2015 Elsevier B.V. All rights reserved.

Bipolar and monopolar radiofrequency treatment of osteoarthritic knee articular cartilage: acute and temporal effects on cartilage compressive stiffness, permeability, cell synthesis, and extracellular matrix composition.

Science.gov (United States)

Cook, James L; Kuroki, Keiichi; Kenter, Keith; Marberry, Kevin; Brawner, Travis; Geiger, Timothy; Jayabalan, Prakash; Bal, B Sonny

2004-04-01

The cellular, biochemical, biomechanical, and histologic effects of radiofrequency-generated heat on osteoarthritic cartilage were assessed. Articular cartilage explants (n=240) from 26 patients undergoing total knee arthroplasty were divided based on Outerbridge grade (I or II/III) and randomly assigned to receive no treatment (controls) or monopolar or bipolar radiofrequency at 15 or 30 W. Both potentially beneficial and harmful effects of radiofrequency treatment of articular cartilage were noted. It will be vital to correlate data from in vitro and in vivo study of radiofrequency thermal chondroplasty to determine the clinical usefulness of this technique.

Radiofrequency (thermal) ablation versus no intervention or other interventions for hepatocellular carcinoma

DEFF Research Database (Denmark)

Weis, Sebastian; Franke, Annegret; Mössner, Joachim

2013-01-01

Hepatocellular carcinoma is the fifth most common cancer worldwide. Percutaneous interventional therapies, such as radiofrequency (thermal) ablation (RFA), have been developed for early hepatocellular carcinoma. RFA competes with other interventional techniques such as percutaneous ethanol...

Sacroiliac joint pain: Prospective, randomised, experimental and comparative study of thermal radiofrequency with sacroiliac joint block.

Science.gov (United States)

Cánovas Martínez, L; Orduña Valls, J; Paramés Mosquera, E; Lamelas Rodríguez, L; Rojas Gil, S; Domínguez García, M

2016-05-01

To compare the analgesic effects between the blockade and bipolar thermal radiofrequency in the treatment of sacroiliac joint pain. Prospective, randomised and experimental study conducted on 60 patients selected in the two hospitals over a period of nine months, who had intense sacroiliac joint pain (Visual Analogue Scale [VAS]>6) that lasted more than 3 months. Patients were randomised into three groups (n=20): Group A (two intra-articular sacroiliac injections of local anaesthetic/corticosteroid guided by ultrasound in 7 days). Group B: conventional bipolar radiofrequency "palisade". Target points were the lateral branch nerves of S1, S2, and S3, distance needles 1cm. Group C: modified bipolar radiofrequency "palisade" (needle distance >1cm). Patients were evaluated at one month, three months, and one year. Demographic data, VAS reduction, and side effects of the techniques were assessed. One month after the treatment, pain reduction was >50% in the three groups PDolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Par and IR reflectance, transmittance, and absorptance of four crop canopies

International Nuclear Information System (INIS)

Wanjura, D.F.; Hatfield, J.L.

1986-01-01

Reflectance, transmittance and absorptance of electromagnetic radiation by cotton, soybeans, grain sorghum, and sunflower was measured at three growth stages in two wavebands (PAR: 0.4 to 0.7 pun and IR: 0.7 to 1.1 yim). As leaf area increased in each crop there were increases in IR reflectance and PAR absorptance and decreases in PAR reflectance and both PAR and IR transmittance. IR radiation was concentrated at the soil surface between rows by reflectance from the sides of canopies when crop cover was less than 80%. Across all crops one parameter, leaf overlap index, explained 81 and 71% of the PAR reflectance and another, crop cover, explained 86 and 94% of IR reflectance from rows and interrows, respectively. Attenuation of PAR radiation through the canopies of cotton and sunflower was similar (K = 0.62 and 0.67) but different from that of soybeans and grain sorghum (K = 0.46 and 0.43) which were the same

Épidémiologie de l'intoxication par envenimation chez les enfants ...

African Journals Online (AJOL)

Introduction: L'intoxication par envenimation est l'ensemble des manifestations locales et générales induites par la pénétration dans l'organisme d'une substance toxique produite par un animal venimeux. Le but de notre travail était d'étudier les signes cliniques des intoxications par envenimation chez les enfants de 0 à 15 ...

PARs for combustible gas control in advanced light water reactors

International Nuclear Information System (INIS)

Hosler, J.; Sliter, G.

1997-01-01

This paper discusses the progress being made in the United States to introduce passive autocatalytic recombiner (PAR) technology as a cost-effective alternative to electric recombiners for controlling combustible gas produced in postulated accidents in both future Advanced Light Water Reactors (ALWRs) and certain U. S. operating nuclear plants. PARs catalytically recombine hydrogen and oxygen, gradually producing heat and water vapor. They have no moving parts and are self-starting and self-feeding, even under relatively cold and wet containment conditions. Buoyancy of the hot gases they create sets up natural convective flow that promotes mixing of combustible gases in a containment. In a non-inerted ALWR containment, two approaches each employing a combination of PARs and igniters are being considered to control hydrogen in design basis and severe accidents. In pre-inerted ALWRs, PARs alone control radiolytic oxygen produced in either accident type. The paper also discusses regulatory feedback regarding these combustible gas control approaches and describes a test program being conducted by the Electric Power Research Institute (EPRI) and Electricite de France (EdF) to supplement the existing PAR test database with performance data under conditions of interest to U.S. plants. Preliminary findings from the EPRI/EdF PAR model test program are included. Successful completion of this test program and confirmatory tests being sponsored by the U. S. NRC are expected to pave the way for use of PARs in ALWRs and operating plants. (author)

Study of electronic field emission from large surfaces under static operating conditions and hyper-frequency; Etude de l'emision electronique par effet de champ sur des surfaces larges en regime statique et hyperfrequence

Energy Technology Data Exchange (ETDEWEB)

Luong, M

1997-09-01

The enhanced electronic field emission from large area metallic surfaces lowers performances of industrial devices that have to sustain high electric field under vacuum. Despite of numerous investigations in the past, the mechanisms of such an emission have never been well clarified. Recently, research in our laboratory has pointed out the importance played by conducting sites (particles and protrusions). A refined geometrical model, called superposed protrusions model has been proposed to explain the enhanced emission by local field enhancement. As a logical continuation, the present work aims at testing this model and, in the same time, investigating the means to suppress the emission where it is undesirable. Thus, we have showed: the cause of current fluctuations in a continuous field regime (DC), the identity of emission characteristics ({beta}, A{sub e}) in both radiofrequency (RF) and DC regimes, the effectiveness of a thermal treatment by extern high density electronic bombardment, the effectiveness of a mechanical treatment by high pressure rinsing with ultra pure water, the mechanisms and limits of an in situ RF processing. Furthermore, the electronic emission from insulating particles has also been studied concurrently with a spectral analysis of the associated luminous emission. Finally, the refined geometrical model for conducting sites is reinforced while another model is proposed for some insulating sites. Several emission suppressing treatments has been explored and validated. At last, the characteristic of a RF pulsed field emitted electron beam has been checked for the first time as a possible application of such a field emission. (author)

Performance of an iodine-fueled radio-frequency ion-thruster

Science.gov (United States)

Holste, Kristof; Gärtner, Waldemar; Zschätzsch, Daniel; Scharmann, Steffen; Köhler, Peter; Dietz, Patrick; Klar, Peter J.

2018-01-01

Two sets of performance data of the same radio-frequency ion-thruster (RIT) have been recorded using iodine and xenon, respectively, as propellant. To characterize the thruster's performance, we have recorded the radio-frequency DC-power, required for yielding preset values of the extracted ion-beam currents, as a function of mass flow. For that purpose, an iodine mass flow system had to be developed, calibrated, and integrated into a newly-built test facility for studying corrosive propellants. The performance mappings for iodine and xenon differ significantly despite comparable operation conditions. At low mass flows, iodine exhibits the better performance. The situation changes at higher mass flows where the performance of iodine is significantly poorer than that of xenon. The reason is very likely related to the molecular nature of iodine. Our results show that iodine as propellant is compatible with RIT technology. Furthermore, it is a viable alternative as propellant for dedicated space missions. In particular, when taking into account additional benefits such as possible storage as a solid and its low price the use of iodine as propellant in ion thrusters is competitive.

Brulure par Plaque de Bistouri Electrique: a Propos de Quatre Cas

Science.gov (United States)

Khales, A.; Achbouk, A.; Belmir, R.; Cherkab, L.; Ennouhi, M.A.; Ababou, K.; Ihrai, H.

2010-01-01

Summary La brûlure par plaque de bistouri électrique est un accident rare mais grave par la profondeur de la lésion et par sa localisation, surtout quand qu’elle survient dans un contexte chirurgical dont le vécu reste difficile de la part du malade et du chirurgien. Cette brûlure bien que imprévisible reste grave par la profondeur et la localisation de la brûlure et par sa survenue dans un contexte opératoire, chez des patients malades. La prise en charge de la brûlure doit se faire en milieu spécialisé. La prévention reste le seul moyen d’éviter ce type d’accident. PMID:21991216

Breakdown criteria due to radio-frequency fields in vacuum. Final report

International Nuclear Information System (INIS)

Reid, D.W.; Lohsen, R.A.

1982-01-01

The factors that affect the voltage at which vacuum gaps break down are analyzed. Based on the literature and some simplifying assumptions, a functional dependence is hypothesized. The hypothesis is related to a proposed experiment using radio-frequency power to generate the breakdown voltage

Computed tomography findings after radiofrequency ablation in locally advanced pancreatic cancer

NARCIS (Netherlands)

Rombouts, Steffi J. E.; Derksen, Tyche C.; Nio, Chung Y.; van Hillegersberg, Richard; van Santvoort, Hjalmar C.; Walma, Marieke S.; Molenaar, Izaak Q.; van Leeuwen, Maarten S.

2018-01-01

The purpose of the study was to provide a systematic evaluation of the computed tomography(CT) findings after radiofrequency ablation (RFA) in locally advanced pancreatic cancer(LAPC). Eighteen patients with intra-operative RFA-treated LAPC were included in a prospective case series. All CT-scans

Active stabilization of ion trap radiofrequency potentials

Energy Technology Data Exchange (ETDEWEB)

Johnson, K. G.; Wong-Campos, J. D.; Restelli, A.; Landsman, K. A.; Neyenhuis, B.; Mizrahi, J.; Monroe, C. [Joint Quantum Institute and University of Maryland Department of Physics, College Park, Maryland 20742 (United States)

2016-05-15

We actively stabilize the harmonic oscillation frequency of a laser-cooled atomic ion confined in a radiofrequency (rf) Paul trap by sampling and rectifying the high voltage rf applied to the trap electrodes. We are able to stabilize the 1 MHz atomic oscillation frequency to be better than 10 Hz or 10 ppm. This represents a suppression of ambient noise on the rf circuit by 34 dB. This technique could impact the sensitivity of ion trap mass spectrometry and the fidelity of quantum operations in ion trap quantum information applications.

Elusloom lennukiga puhkusele / Inge Parring

Index Scriptorium Estoniae

Parring, Inge

2003-01-01

Ilmunud ka: Delovõje Vedomosti 1. okt. lk. 13. Air Cargo Estonia/ACE Logisticsi müügijuht Inge Parring tutvustab elusloomade transpordivõimalusi. Vt. samas: Loomade transportimiseks vajalikud dokumendid

suPAR

DEFF Research Database (Denmark)

Eugen-Olsen, Jesper; Giamarellos-Bourboulis, Evangelos J

2015-01-01

Investigation of biomarkers that can promptly predict unfavourable outcome of critically illness is an emerging necessity taking into consideration the need for early intervention, the shortage of available beds in intensive care units and the considerable cost of hospitalisation. The most...... promising biomarker is soluble urokinase-type plasminogen activator receptor (suPAR). Three studies in large populations of critically ill patients and patients admitted to the emergency department have shown that concentrations >12ng/mL can safely predict unfavourable outcome. This review presents...

Urine suPAR levels compared with plasma suPAR levels as predictors of post-consultation mortality risk among individuals assumed to be TB-negative: a prospective cohort study

DEFF Research Database (Denmark)

Rabna, Paulo; Andersen, Andreas; Wejse, Christian

2010-01-01

-suPAR was measured using a commercial ELISA (suPARnostic®). We found that U-suPAR carried significant prognostic information on mortality for HIV-infected subjects with an area under the ROC curve of 0.75. For HIV-negative individuals, little or no prognostic effect was observed. However, in both HIV positives...... and negatives, the predictive effect of U-suPAR was found to be inferior to that of P-suPAR....

Brésil : La contamination par le mercure en Amazonie | CRDI ...

International Development Research Centre (IDRC) Digital Library (Canada)

11 janv. 2011 ... En tentant de déceler la source de la contamination de l'Amazone par le ... par Jean-Rémy Davy Guimaraes de l'Université fédérale de Rio de Janeiro ... ces mattes est circonscrite par la conservation et la restauration en rive.

Diverse Radiofrequency Sensitivity and Radiofrequency Effects of Mobile or Cordless Phone near Fields Exposure in Drosophila melanogaster

Science.gov (United States)

Geronikolou, Styliani; Zimeras, Stelios; Davos, Constantinos H.; Michalopoulos, Ioannis; Tsitomeneas, Stephanos

2014-01-01

Introduction The impact of electromagnetic fields on health is of increasing scientific interest. The aim of this study was to examine how the Drosophila melanogaster animal model is affected when exposed to portable or mobile phone fields. Methods/Results Two experiments have been designed and performed in the same laboratory conditions. Insect cultures were exposed to the near field of a 2G mobile phone (the GSM 2G networks support and complement in parallel the 3G wide band or in other words the transmission of information via voice signals is served by the 2G technology in both mobile phones generations) and a 1880 MHz cordless phone both digitally modulated by human voice. Comparison with advanced statistics of the egg laying of the second generation exposed and non-exposed cultures showed limited statistical significance for the cordless phone exposed culture and statistical significance for the 900 MHz exposed insects. We calculated by physics, simulated and illustrated in three dimensional figures the calculated near fields of radiation inside the experimenting vials and their difference. Comparison of the power of the two fields showed that the difference between them becomes null when the experimental cylinder radius and the height of the antenna increase. Conclusions/Significance Our results suggest a possible radiofrequency sensitivity difference in insects which may be due to the distance from the antenna or to unexplored intimate factors. Comparing the near fields of the two frequencies bands, we see similar not identical geometry in length and height from the antenna and that lower frequencies tend to drive to increased radiofrequency effects. PMID:25402465

Diverse radiofrequency sensitivity and radiofrequency effects of mobile or cordless phone near fields exposure in Drosophila melanogaster.

Directory of Open Access Journals (Sweden)

Styliani Geronikolou

Full Text Available INTRODUCTION: The impact of electromagnetic fields on health is of increasing scientific interest. The aim of this study was to examine how the Drosophila melanogaster animal model is affected when exposed to portable or mobile phone fields. METHODS/RESULTS: Two experiments have been designed and performed in the same laboratory conditions. Insect cultures were exposed to the near field of a 2G mobile phone (the GSM 2G networks support and complement in parallel the 3G wide band or in other words the transmission of information via voice signals is served by the 2G technology in both mobile phones generations and a 1880 MHz cordless phone both digitally modulated by human voice. Comparison with advanced statistics of the egg laying of the second generation exposed and non-exposed cultures showed limited statistical significance for the cordless phone exposed culture and statistical significance for the 900 MHz exposed insects. We calculated by physics, simulated and illustrated in three dimensional figures the calculated near fields of radiation inside the experimenting vials and their difference. Comparison of the power of the two fields showed that the difference between them becomes null when the experimental cylinder radius and the height of the antenna increase. CONCLUSIONS/SIGNIFICANCE: Our results suggest a possible radiofrequency sensitivity difference in insects which may be due to the distance from the antenna or to unexplored intimate factors. Comparing the near fields of the two frequencies bands, we see similar not identical geometry in length and height from the antenna and that lower frequencies tend to drive to increased radiofrequency effects.

Skin tightening with a combined unipolar and bipolar radiofrequency device.

Science.gov (United States)

Mayoral, Flor A

2007-02-01

Monopolar radiofrequency (RF) devices are well established treatment modalities for tightening facial skin. A 60-year-old woman presented with a desire to tighten the lax skin and improve the appearance of both upper arms. A combination unipolar and bipolar RF device may provide volume reduction as well as skin tightening in the upper arm.

Effects of Pulsed Versus Conventional Versus Combined Radiofrequency for the Treatment of Trigeminal Neuralgia: A Prospective Study.

Science.gov (United States)

Elawamy, Abdelraheem; Abdalla, Esam Eldein Mohamed; Shehata, Ghaydaa A

2017-09-01

During radiofrequency bursts of energy are applied to nervous tissue. The clinical advantages of this treatment remain unclear. We compared the effectiveness and pain relief for idiopathic trigeminal neuralgia (TN) after continuous radiofrequency (CRF), pulsed radiofrequency (PRF), and combined continuous and pulsed radiofrequency (CCPRF) treatment of the Gasserian ganglion (GG). We conducted a randomized prospective study. Forty-three patients were included. Eleven patients were treated with PRF at 42°C for 10 minutes (PRF group), 12 patients received CRF for 270 seconds at 75 °C (CRF group), and 20 patients received PRF for 10 minutes at 42°C followed by CRF for at 60°C for 270 seconds (CCPRF group). Assuit University Hospital, Pain and Neurology outpatient clinics. Patients were assessed for pain, satisfaction, and consumption of analgesics at baseline and 7 days, one month, 6 months, 12 months, and 24 months after the procedure. The incidence of complications, anesthesia dolorosa, weakness of muscles of mastication, numbness, and technical complications, was evaluated after the procedure. Excellent pain relief was achieved after 6, 12, and 24 months, respectively in 95%, 85%, and 70% of patients with CCPRF; 75%, 75%, and reduced to 50% among patients with CRF; and 82%, reduced to 9.1%, and 0% of patients with PRF. No complications were recorded in 75% of patients in the CCPRF and PRF groups. There was one case of anesthesia dolorosa, 4 cases of masseter muscle weakness, and 5 cases of severe numbness recorded in the CRF group. There was a small number of patients in each group. The best results were observed in the CCPRF group, followed by the CRF group, and then the PRF group.Key words: Pulsed, continuous, radiofrequency, trigeminal neuralgia, Gasserian ganglion.

Electron microscope study of vacancy clusters produced by quenching in magnesium; Etude par microscopie electronique des amas de lacunes crees par trempe dans le magnesium

Energy Technology Data Exchange (ETDEWEB)

Levy, V; Espinasse, J; Mairy, C; Hillairet, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-07-01

Vacancy clustering in quenched magnesium has been studied by transmission electron microscopy. The nature of the vacancy loops observed, seems to depend essentially on the impurity content of the metal; this effect can be attributed to a variation of the stacking fault energy of magnesium due to impurities. (authors) [French] On a etudie par microscopie electronique en transmission les defauts crees par trempe dans le magnesium. Un effet considerable des impuretes du metal sur la nature des boucles obtenues par condensation de lacunes a ete mis en evidence; cet effet semble s'expliquer de facon satisfaisante par un abaissement de l'energie de faute d'empilement du magnesium du aux impuretes. (auteur)

Probing the fundamental limit of niobium in high radiofrequency fields by dual mode excitation in superconducting radiofrequency cavities

International Nuclear Information System (INIS)

Eremeev, Grigory; Geng, Rongli; Palczewski, Ari

2011-01-01

We have studied thermal breakdown in several multicell superconducting radiofrequency cavity by simultaneous excitation of two TM 010 passband modes. Unlike measurements done in the past, which indicated a clear thermal nature of the breakdown, our measurements present a more complex picture with interplay of both thermal and magnetic effects. JLab LG-1 that we studied was limited at 40.5 MV/m, corresponding to B peak = 173 mT, in 89 mode. Dual mode measurements on this quench indicate that this quench is not purely magnetic, and so we conclude that this field is not the fundamental limit in SRF cavities

ParABS Systems of the Four Replicons of Burkholderia cenocepacia: New Chromosome Centromeres Confer Partition Specificity†

Science.gov (United States)

Dubarry, Nelly; Pasta, Franck; Lane, David

2006-01-01

Most bacterial chromosomes carry an analogue of the parABS systems that govern plasmid partition, but their role in chromosome partition is ambiguous. parABS systems might be particularly important for orderly segregation of multipartite genomes, where their role may thus be easier to evaluate. We have characterized parABS systems in Burkholderia cenocepacia, whose genome comprises three chromosomes and one low-copy-number plasmid. A single parAB locus and a set of ParB-binding (parS) centromere sites are located near the origin of each replicon. ParA and ParB of the longest chromosome are phylogenetically similar to analogues in other multichromosome and monochromosome bacteria but are distinct from those of smaller chromosomes. The latter form subgroups that correspond to the taxa of their hosts, indicating evolution from plasmids. The parS sites on the smaller chromosomes and the plasmid are similar to the “universal” parS of the main chromosome but with a sequence specific to their replicon. In an Escherichia coli plasmid stabilization test, each parAB exhibits partition activity only with the parS of its own replicon. Hence, parABS function is based on the independent partition of individual chromosomes rather than on a single communal system or network of interacting systems. Stabilization by the smaller chromosome and plasmid systems was enhanced by mutation of parS sites and a promoter internal to their parAB operons, suggesting autoregulatory mechanisms. The small chromosome ParBs were found to silence transcription, a property relevant to autoregulation. PMID:16452432

Results of radiofrequency ablation of liver tumors: experience of 134 cases

Directory of Open Access Journals (Sweden)

Marcelo Augusto Fontenelle Ribeiro Junior

2008-12-01

Full Text Available Objective: To study radiofrequency ablation of primary and metastatic livertumors. Methods: The authors present a series of 134 cases, 63 femalesand 71 males with a mean age of 61.2 years, in whom radiofrequencyablation was used either by laparotomy or percutaneously to treat 203lesions. The group was composed of 51 cases of hepatocellular carcinoma,four cases of cholangiocarcinoma, and cases of hepatic metastases, asfollows: 64 of colorectal cancer, 6 of neuroendocrine tumors, 5 of breastcancer, 1 case of pancreas cancer, 1 of kidney cancer, 1 of endometrialcancer and 1 of leiomyosarcoma. Results: Procedure-associatedmorbidity/mortality was 24.8 and 3.7%, respectively. Recurrence wasobserved in 12.7% within a mean time of 10.5 months. Conclusions:Radiofrequency ablation is a safe procedure and can be used in patientswith impaired hepatic function. For metastatic diseases, it does notreplace surgery but it can be associated with other procedures, such assurgery and transarterial chemoembolization, or after recurrence, leadingto greater probability of remaining disease-free.

Nonsurgical Transurethral Radiofrequency Collagen Denaturation: Results at Three Years after Treatment

Directory of Open Access Journals (Sweden)

Denise M. Elser

2011-01-01

Full Text Available Objective. To assess treatment efficacy and quality of life in women with stress urinary incontinence 3 years after treatment with nonsurgical transurethral radiofrequency collagen denaturation. Methods. This prospective study included 139 women with stress urinary incontinence due to bladder outlet hypermobility. Radiofrequency collagen denaturation was performed using local anesthesia in an office setting. Assessments included incontinence quality of life (I-QOL and urogenital distress inventory (UDI-6 instruments. Results. In total, 139 women were enrolled and 136 women were treated (mean age, 47 years. At 36 months, intent-to-treat analysis (n=139 revealed significant improvements in quality of life. Mean I-QOL score improved 17 points from baseline (P=.0004, while mean UDI-6 score improved (decreased 19 points (P=.0005. Conclusions. Transurethral collagen denaturation is a low-risk, office-based procedure that results in durable quality-of-life improvements in a significant proportion of women for as long as 3 years.

3.0 T MR diffusion weighted imaging in the evaluation of radio-frequency ablation of the liver VX2 tumors

International Nuclear Information System (INIS)

Liu Yubao; Liang Changhong; Wang Qiushi; Xie Shufei; Yu Yuanxin; Liu Zaiyi; Zhang Zhonglin

2010-01-01

Objective: To evaluate 3.0 T MR DWI techniques in detecting the lesions of pre and post-radiofrequency ablation of the rabbit liver VX2 tumors. Methods: Twenty two New Zealand white rabbits were used in this experiment. Twenty tumor fragments were implanted into the livers of 20 rabbits respectively. Two normal rabbits were used as controls for radiofrequency ablation of the normal liver. 3. 0 T MR DWI was performed 14 to 21 days after tumor implantation (mean, 17 days) in the tumor-bearing animals. Radiofrequency ablation was performed in the 18 tumor-bearing animals and in the two healthy animals. 3.0 T MRI and DWI were performed 7 to 10 days after radiofrequency ablation (mean, 8 days). Pathology was obtained immediately after the completion of post radiofrequency ablation MR imaging. The MRI features and ADC values of pre- and post -radiofrequency ablation lesions in the livers with VX2 tumors and normal rabbits were analyzed and correlation was made with histopathologic findings. Analysis of variance repeated measures were performed in analyzing the differences among the ADC values of different tissues with the same b value. Results: All 20 rabbit liver models of VX2 tumors were constructed successfully. One rabbit died of anesthetic overdose, another one showed necrosis within the implanted tumor. All 18 untreated VX2 tumors had predominantly low or iso-signal intensity on T 1 WI and high signal intensity on T 2 WI. All 18 VX2 tumors and 2 normal rabbits were treated by radiofrequency ablation successfully. Lesions treated by Radiofrequency ablation displayed low signal intensity on T 1 WI, and high signal intensity on T 2 WI. Seven to 10 days after radiofrequency ablation, lesions varied from having low signal intensity to slightly increased signal intensity on T 1 WI, with areas of mixed (high, intermediate, and low) signal intensity. A peripheral rim of high signal intensity with varying thickness on T 2 WI correlated with granulation tissue, which

MODIS-derived daily PAR simulation from cloud-free images and its validation

Energy Technology Data Exchange (ETDEWEB)

Chen, Liangfu; Gu, Xingfa; Tian, Guoliang [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China); The Center for National Spaceborne Demonstration, Beijing 100101 (China); Gao, Yanhua [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China); Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); Yang, Lei [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China); Jilin University, Changchun 130026 (China); Liu, Qinhuo [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China)

2008-06-15

In this paper, a MODIS-derived daily PAR (photosynthetically active radiation) simulation model from cloud-free image over land surface has been developed based on Bird and Riordan's model. In this model, the total downwelling spectral surface irradiance is divided into two parts: one is beam irradiance, and another is diffuse irradiance. The attenuation of solar beam irradiance comprises scattering by the gas mixture, absorption by ozone, the gas mixture and water vapor, and scattering and absorption by aerosols. The diffuse irradiance is scattered out of the direct beam and towards the surface. The multiple ground-air interactions have been taken into account in the diffuse irradiance model. The parameters needed in this model are atmospheric water vapor content, aerosol optical thickness and spectral albedo ranging from 400 nm to 700 nm. They are all retrieved from MODIS data. Then, the instantaneous photosynthetically available radiation (IPAR) is integrated by using a weighted sum at each of the visible MODIS wavebands. Finally, a daily PAR is derived by integration of IPAR. In order to validate the MODIS-derived PAR model, we compared the field PAR measurements in 2003 and 2004 against the simulated PAR. The measurements were made at the Qianyanzhou ecological experimental station, Chinese Ecosystem Research Network. A total of 54 days of cloud-free MODIS L1B level images were used for the PAR simulation. Our results show that the simulated PAR is consistent with field measurements, where the correlation coefficient of linear regression between calculated PAR and measured PAR is 0.93396. However, there were some uncertainties in the comparison of 1 km pixel PAR with the tower flux stand measurement. (author)

PAR-2 expression in the gingival crevicular fluid reflects chronic periodontitis severity.

Science.gov (United States)

Fukushima, Henrique; Alves, Vanessa Tubero Euzebio; Carvalho, Verônica Franco de; Ambrósio, Lucas Macedo Batitucci; Eichler, Rosangela Aparecida Dos Santos; Carvalho, Maria Helena Catelli de; Saraiva, Luciana; Holzhausen, Marinella

2017-01-26

Recent studies investigating protease-activated receptor type 2 (PAR-2) suggest an association between the receptor and periodontal inflammation. It is known that gingipain, a bacterial protease secreted by the important periodontopathogen Porphyromonas gingivalis can activate PAR-2. Previous studies by our group found that PAR-2 is overexpressed in the gingival crevicular fluid (GCF) of patients with moderate chronic periodontitis (MP). The present study aimed at evaluating whether PAR-2 expression is associated with chronic periodontitis severity. GCF samples and clinical parameters, including plaque and bleeding on probing indices, probing pocket depth and clinical attachment level, were collected from the control group (n = 19) at baseline, and from MP patients (n = 19) and severe chronic periodontitis (SP) (n = 19) patients before and 6 weeks after periodontal non-surgical treatment. PAR-2 and gingipain messenger RNA (mRNA) in the GCF of 4 periodontal sites per patient were evaluated by Reverse Transcription Polymerase Chain Reaction (RT-qPCR). PAR-2 and gingipain expressions were greater in periodontitis patients than in control group patients. In addition, the SP group presented increased PAR-2 and gingipain mRNA levels, compared with the MP group. Furthermore, periodontal treatment significantly reduced (p periodontitis. In conclusion, PAR-2 is associated with chronic periodontitis severity and with gingipain levels in the periodontal pocket, thus suggesting that PAR-2 expression in the GCF reflects the severity of destruction during periodontal infection.

Scheme to funnel ion beams with a radio-frequency quadrupole

International Nuclear Information System (INIS)

Stokes, R.H.; Minerbo, G.N.

1985-01-01

We describe a proposed method to funnel ion beams using a new form of the radio-frequency quadrupole (RFQ) structure. This RFQ accepts two bunched ion beams and combines them into a single final beam with interlaced microstructure pulses. It also provides uninterrupted periodic transverse focusing to facilitate the funneling of beams with high current and low emittance

Molecular mechanism of bundle formation by the bacterial actin ParM

Energy Technology Data Exchange (ETDEWEB)

Popp, David, E-mail: dpopp@imcb.a-star.edu.sg [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, 138673 Singapore (Singapore); Narita, Akihiro [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Nagoya University Graduate School of Science, Structural Biology Research Center and Division of Biological Sciences, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Iwasa, Mitsusada [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Maeda, Yuichiro [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Nagoya University Graduate School of Science, Structural Biology Research Center and Division of Biological Sciences, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Robinson, Robert C. [Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, 138673 Singapore (Singapore)

2010-01-22

The actin homolog ParM plays a microtubule-like role in segregating DNA prior to bacterial cell division. Fluorescence and cryo-electron microscopy have shown that ParM forms filament bundles between separating DNA plasmids in vivo. Given the lack of ParM bundling proteins it remains unknown how ParM bundles form at the molecular level. Here we show using time-lapse TIRF microscopy, under in vitro molecular crowding conditions, that ParM-bundle formation consists of two distinct phases. At the onset of polymerization bundle thickness and shape are determined in the form of nuclei of short helically disordered filaments arranged in a liquid-like lattice. These nuclei then undergo an elongation phase whereby they rapidly increase in length. At steady state, ParM bundles fuse into one single large aggregate. This behavior had been predicted by theory but has not been observed for any other cytomotive biopolymer, including F-actin. We employed electron micrographs of ParM rafts, which are 2-D analogs of 3-D bundles, to identify the main molecular interfilament contacts within these suprastructures. The interface between filaments is similar for both parallel and anti-parallel orientations and the distribution of filament polarity is random within a bundle. We suggest that the interfilament interactions are not due to the interactions of specific residues but rather to long-range, counter ion mediated, electrostatic attractive forces. A randomly oriented bundle ensures that the assembly is rigid and that DNA may be captured with equal efficiency at both ends of the bundle via the ParR binding protein.

Percutaneous radiofrequency ablation of lung metastases from colorectal carcinoma under C-arm cone beam CT guidance.

Science.gov (United States)

Amouyal, G; Pernot, S; Déan, C; Cholley, B; Scotté, F; Sapoval, M; Pellerin, O

2017-11-01

The aim of this study was to assess the feasibility, safety and efficacy of percutaneous radiofrequency ablation of lung metastases from colorectal carcinoma using C-arm cone beam computed tomography (CBCT) guidance. This single-center prospective observational study was performed from August 2013 to August 2016, and included consecutive patients referred for radiofrequency ablation of lung metastases from colorectal cancer. Radiofrequency ablation procedures were performed under C-arm CBCT guidance. Feasibility was assessed by probe accuracy placement, time to accurate placement and number of C-arm CBCT acquisitions to reach the target lesion. Safety was assessed by the report of adverse event graded using the common terminology criteria for adverse events (CTCAE-V4.0). Efficacy was assessed by metastases response rate using RECIST 1.1 and 18 FDG-PET-CT tumor uptake at 6months. Fifty-four consecutive patients (32 men, 22 women) with a mean age of 63±8 (SD) years (range: 51-81years) with a total of 56 lung metastasis from colorectal metastases were treated in a single session. The mean tumor diameter was 25.6±4.5 (SD)mm (range: 17-31mm). Median time to insert the needle into the target lesion was 10min (range: 5-25min). Median number of needles repositioning and C-arm CBCT acquisition per patient was 1 (range: 0-3) and 4 (range: 3-6) respectively. The accuracy for radiofrequency ablation probe placement was 2±0.2 (SD)mm (range: 0-9mm). Pneumothorax requiring chest tube placement occurred in one patient (CTCAE-V4.0 grade 3). At 6months, all patients were alive with tumor response rate of -27% and had no significant activity on the 18 FDG-PET CT follow-up. Percutaneous radiofrequency ablation of lung metastases from colorectal cancer under C-arm CBCT guidance is feasible and safe, with immediate and short-term results similar to those obtained using conventional CT guidance. Copyright © 2017 Éditions françaises de radiologie. Published by Elsevier Masson SAS

Pulsed Radiofrequency in the Treatment of Persistent Pain After Inguinal Herniotomy

DEFF Research Database (Denmark)

Werner, Mads U; Bischoff, Joakim Mutahi; Rathmell, James P

2012-01-01

. The use of pulsed radiofrequency (PFR), leading to nondestructive lesions of nerve structures, has been proposed as a treatment option. To examine the evidence of treatment efficacy, a systematic literature search was made. From the databases PubMed, Embase, and CINAHL, 4 case reports were retrieved and 8...

From mini-invasive to non-invasive treatment using monopolar radiofrequency: the next orthopaedic frontier.

Science.gov (United States)

Whipple, Terry L

2009-10-01

Tendinopathy arises from a failed tendon healing process. Current non-invasive therapeutic alternatives are anti-inflammatory in nature, and outcomes are unpredictable. The benefit of invasive alternatives resides in the induction of the healing response. A new technology that uses non-invasive monopolar capacitive coupled radiofrequency has demonstrated the ability to raise temperatures in tendons and ligaments above 50 degrees C, the threshold for collagen modulation, tissue shrinkage and recruitment of macrophages, fibroblasts, and heat shock protein factors, without damaging the overlying structures, resulting in activation of the wound healing response. Monopolar capacitive-coupled radiofrequency offers a new non-invasive choice for tendinopathies and sprained ligaments. It does not interfere with subsequent surgical procedures should they become necessary.

Selective percutaneous radiofrequency thermocoagulation in the treatment of trigeminal neuralgia:report on 1860 cases

Institute of Scientific and Technical Information of China (English)

吴承远; 孟凡刚; 徐淑军; 刘玉光; 王宏伟

2004-01-01

@@Trigeminal neuralgia (TN) is defined by the International Association for the Study of Pain as "a sudden, usually unilateral, severe, brief, stabbing, recurrent pain in the distribution of one or more branches of the fifth cranial nerve".1 The incidence rate is about three to five cases per year per 100000 persons and increases with age.2 In our hospital, percutaneous radiofrequency therapy was performed on 1860 patients with TN from June 1986 to April 2003, and percutaneous trigeminal ganglion radiofrequency therapy on 579 cases. Among this group of patients, X-ray, 3-D CT, and navigational localization of the oval foramen were performed on 42 cases. The indications, techniques, and results are reported here.

Par Pond vegetation status Summer 1995 -- October survey descriptive summary

International Nuclear Information System (INIS)

Mackey, H.E. Jr.; Riley, R.S.

1995-11-01

The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the emergent shoreline aquatic plant communities began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level and continued with this late October survey. Communities similar to the pre-drawdown Par Pond aquatic plant communities are becoming re-established; especially, beds of maiden cane, lotus, waterlily, and watershield are now extensive and well established. Cattail occurrence continues to increase, but large beds common to Par Pond prior to the drawdown have not formed. Future surveys throughout 1996 and 1997, along with the continued evaluation of satellite data to map the areal extent of the macrophyte beds of Par Pond, are planned

Par Pond vegetation status Summer 1995 -- September survey descriptive summary

International Nuclear Information System (INIS)

Mackey, H.E. Jr.; Riley, R.S.

1995-09-01

The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the emergent shoreline aquatic plant communities began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level and continued with this mid-September survey. Communities similar to the pre-drawdown Par Pond aquatic plant communities are becoming re-established; especially, beds of maidencane, lotus, waterlily, and watershield are now extensive and well established. Cattail occurrence continues to increase, but large beds common to Par Pond prior to the drawdown have not formed. Future surveys during the late growing seasons of 1995, and throughout 1996 and 1997, along with the evaluation of satellite data to map the areal extent of the macrophyte beds of Par Pond, are planned

Radiofrequency ablation for unresectable locally advanced pancreatic cancer: a systematic review

Science.gov (United States)

Fegrachi, Samira; Besselink, Marc G; van Santvoort, Hjalmar C; van Hillegersberg, Richard; Molenaar, Izaak Quintus

2014-01-01

Background: Median survival in patients with unresectable locally advanced pancreatic cancer lies in the range of 9–15 months. Radiofrequency ablation (RFA) may prolong survival, but data on its safety and efficacy are scarce. Methods: A systematic literature search was performed in PubMed, EMBASE and the Cochrane Library with the syntax ‘(radiofrequency OR RFA) AND (pancreas OR pancreatic)’ for studies published until 1 January 2012. In addition, a search of the proceedings of conferences on pancreatic disease that took place during 2009–2011 was performed. Studies with fewer than five patients were excluded as they were considered to be case reports. The primary endpoint was survival. Secondary endpoints included morbidity and mortality. Results: Five studies involving a total of 158 patients with pancreatic cancer treated with RFA fulfilled the eligibility criteria. These studies reported median survival after RFA of 3–33 months, morbidity related to RFA of 4–37%, mortality of 0–19% and overall morbidity of 10–43%. Pooling of data was not appropriate as the study populations and reported outcomes were heterogeneous. Crucial safety aspects included ensuring a maximum RFA tip temperature of < 90 °C and ensuring minimum distances between the RFA probe and surrounding structures. Conclusions: Radiofrequency ablation seems to be feasible and safe when it is used with the correct temperature and at an appropriate distance from vital structures. It appears to have a positive impact on survival. Multicentre randomized trials are necessary to determine the true effect size of RFA and to minimize the impacts of selection and publication biases. PMID:23600801

RADIO-FREQUENCY MASS SPECTROMETERS AND THEIR APPLICATIONS IN SPACE

Energy Technology Data Exchange (ETDEWEB)

Gilmour, Jr., A. S.

1963-08-15

The operation of three common radio-frequency mass spectrometers is described, and their performances are compared. Their limitations are pointed out. It is concluded that the quadrupole spectrometer has fewer limitations and is more generally useful in space probes than the other devices. Some present and proposed uses of spectrometers in space are discussed, and the problem of contamination of the atmosphere being sampled by the spectrometer is reviewed. (auth)

Improved Satellite-based Photosysnthetically Active Radiation (PAR) for Air Quality Studies

Science.gov (United States)

Pour Biazar, A.; McNider, R. T.; Cohan, D. S.; White, A.; Zhang, R.; Dornblaser, B.; Doty, K.; Wu, Y.; Estes, M. J.

2015-12-01

One of the challenges in understanding the air quality over forested regions has been the uncertainties in estimating the biogenic hydrocarbon emissions. Biogenic volatile organic compounds, BVOCs, play a critical role in atmospheric chemistry, particularly in ozone and particulate matter (PM) formation. In southeastern United States, BVOCs (mostly as isoprene) are the dominant summertime source of reactive hydrocarbon. Despite significant efforts in improving BVOC estimates, the errors in emission inventories remain a concern. Since BVOC emissions are particularly sensitive to the available photosynthetically active radiation (PAR), model errors in PAR result in large errors in emission estimates. Thus, utilization of satellite observations to estimate PAR can help in reducing emission uncertainties. Satellite-based PAR estimates rely on the technique used to derive insolation from satellite visible brightness measurements. In this study we evaluate several insolation products against surface pyranometer observations and offer a bias correction to generate a more accurate PAR product. The improved PAR product is then used in biogenic emission estimates. The improved biogenic emission estimates are compared to the emission inventories over Texas and used in air quality simulation over the period of August-September 2013 (NASA's Discover-AQ field campaign). A series of sensitivity simulations will be performed and evaluated against Discover-AQ observations to test the impact of satellite-derived PAR on air quality simulations.

Measurement of radiofrequency fields

International Nuclear Information System (INIS)

Leonowich, J.A.

1992-05-01

We are literally surrounded by radiofrequency (RFR) and microwave radiation, from both natural and man-made sources. The identification and control of man-made sources of RFR has become a high priority of radiation safety professionals in recent years. For the purposes of this paper, we will consider RFR to cover the frequencies from 3 kHz to 300 MHz, and microwaves from 300 MHz to 300 GHz, and will use the term RFR interchangeably to describe both. Electromagnetic radiation and field below 3 kHz is considered Extremely Low Frequency (ELF) and will not be discussed in this paper. Unlike x- and gamma radiation, RFR is non-ionizing. The energy of any RFR photon is insufficient to produce ionizations in matter. The measurement and control of RFR hazards is therefore fundamentally different from ionizing radiation. The purpose of this paper is to acquaint the reader with the fundamental issues involved in measuring and safely using RFR fields. 23 refs

Radiotelemetry and wildlife: Highlighting a gap in the knowledge on radiofrequency radiation effects

International Nuclear Information System (INIS)

Balmori, Alfonso

2016-01-01

Radio transmitters and associated devices may induce negative effects that can bias the results of ongoing research. The main documented effects of radio transmitters on animals include reduced survival, decreased productivity, changes in behaviour and movement patterns and a biased sex ratio. The only factors that have claimed responsibility for these possible damages are the weight of the radio transmitter and associated devices, and the attachment type. The electromagnetic radiation produced by radio transmitters has not been considered so far in research. There have been no studies evaluating the effects of non-ionising electromagnetic radiation (radiofrequency signals) necessary for tracking, although the problems found were significantly associated with the length of time that animals had been carrying their radio transmitters. Similar problems as those in radiotracked animals have been found in numerous studies with animals exposed to radiofrequency radiation for a sufficient amount of time. Laboratory scientists investigating the orientation of animals know they have to shield the place where experiments are performed to prevent interference from man-made radiation, as anthropogenic signals may distort the results. It is paradoxical that, at the same time, field scientists investigating the movements and other aspects of animal biology are providing animals with radio transmitters that emit the same type of radiation, since this may affect the results concerning their orientation and movement. This paper identifies gaps in the knowledge that should be investigated in-depth. The possibility that the radiofrequency radiation from radiotracking devices is responsible for the findings should be considered. Considering this factor may allow researchers to best understand the long-term effects found. - Highlights: • Radiotracking may induce negative effects that can bias the results. • Effects have been documented on survival, reproduction and behaviour. �

Radiotelemetry and wildlife: Highlighting a gap in the knowledge on radiofrequency radiation effects

Energy Technology Data Exchange (ETDEWEB)

Balmori, Alfonso, E-mail: balmaral@jcyl.es

2016-02-01

Radio transmitters and associated devices may induce negative effects that can bias the results of ongoing research. The main documented effects of radio transmitters on animals include reduced survival, decreased productivity, changes in behaviour and movement patterns and a biased sex ratio. The only factors that have claimed responsibility for these possible damages are the weight of the radio transmitter and associated devices, and the attachment type. The electromagnetic radiation produced by radio transmitters has not been considered so far in research. There have been no studies evaluating the effects of non-ionising electromagnetic radiation (radiofrequency signals) necessary for tracking, although the problems found were significantly associated with the length of time that animals had been carrying their radio transmitters. Similar problems as those in radiotracked animals have been found in numerous studies with animals exposed to radiofrequency radiation for a sufficient amount of time. Laboratory scientists investigating the orientation of animals know they have to shield the place where experiments are performed to prevent interference from man-made radiation, as anthropogenic signals may distort the results. It is paradoxical that, at the same time, field scientists investigating the movements and other aspects of animal biology are providing animals with radio transmitters that emit the same type of radiation, since this may affect the results concerning their orientation and movement. This paper identifies gaps in the knowledge that should be investigated in-depth. The possibility that the radiofrequency radiation from radiotracking devices is responsible for the findings should be considered. Considering this factor may allow researchers to best understand the long-term effects found. - Highlights: • Radiotracking may induce negative effects that can bias the results. • Effects have been documented on survival, reproduction and behaviour. �

Mathematical 3D modelling and sensitivity analysis of multipolar radiofrequency ablation in the spine.

Science.gov (United States)

Matschek, Janine; Bullinger, Eric; von Haeseler, Friedrich; Skalej, Martin; Findeisen, Rolf

2017-02-01

Radiofrequency ablation is a valuable tool in the treatment of many diseases, especially cancer. However, controlled heating up to apoptosis of the desired target tissue in complex situations, e.g. in the spine, is challenging and requires experienced interventionalists. For such challenging situations a mathematical model of radiofrequency ablation allows to understand, improve and optimise the outcome of the medical therapy. The main contribution of this work is the derivation of a tailored, yet expandable mathematical model, for the simulation, analysis, planning and control of radiofrequency ablation in complex situations. The dynamic model consists of partial differential equations that describe the potential and temperature distribution during intervention. To account for multipolar operation, time-dependent boundary conditions are introduced. Spatially distributed parameters, like tissue conductivity and blood perfusion, allow to describe the complex 3D environment representing diverse involved tissue types in the spine. To identify the key parameters affecting the prediction quality of the model, the influence of the parameters on the temperature distribution is investigated via a sensitivity analysis. Simulations underpin the quality of the derived model and the analysis approach. The proposed modelling and analysis schemes set the basis for intervention planning, state- and parameter estimation, and control. Copyright © 2016. Published by Elsevier Inc.

SAFARI 2000 PAR Measurements, Kalahari Transect, Botswana, Wet Season 2000

Data.gov (United States)

National Aeronautics and Space Administration — Ceptometer data from a Decagon AccuPAR (Model PAR-80) were collected at four sites in Botswana during the SAFARI 2000 Kalahari Transect Wet Season Campaign (March,...

Lumbar lordosis and pars interarticularis fractures: a case-control study

International Nuclear Information System (INIS)

Bugg, William G.; Lewis, Mark; Juette, Arne; Cahir, John G.; Toms, Andoni P.

2012-01-01

The aim of this study is to examine the relationship between lumbar lordosis and pars interarticularis fractures. In this retrospective case-control study we compare the angle of lumbar lordosis and the angle of the S1 vertebral endplate (as a measure of pelvic tilt) in patients with bilateral L5 pars interarticularis fractures with age- and sex-matched control cases with normal MRI examinations of the lumbar spine. Twenty-nine cases of bilateral L5 pars interarticularis fractures with matched control-cases were identified on MRI (16 male, 13 female, age 9-63 years). The angle of lordosis was measured between the inferior L4 and superior S1 vertebral endplates on a standing lateral lumbar spine radiograph for both groups. The mean angle of lordosis about the L5 vertebra was 36.9 (SD = 6.5 ) in the pars interarticularis fracture group, and 30.1 (SD = 6.4 ) in the control group. The difference between the two groups was significant (mean difference 6.8 , Student's t test: P < 0.001). The mean angle of sacral tilt measured was 122.2 (SD = 10.16 ) for controls and 136.4 (SD = 10.86 ) for patients with pars defects. The difference in the means of 14.2 was statistically significantly different (P < 0.0001). Sacral tilt represented by a steeply angled superior endplate of S1 is associated with a significantly increased angle of lordosis, between L4 and S1, and pars fractures at L5. Steep angulation of the first sacral vertebral segment maybe the predisposing biomechanical factor that leads to pincer-like impingement of the pars interarticularis and then spondylolysis. (orig.)

Lumbar lordosis and pars interarticularis fractures: a case-control study

Energy Technology Data Exchange (ETDEWEB)

Bugg, William G; Lewis, Mark; Juette, Arne; Cahir, John G; Toms, Andoni P [Cotman Centre, Norwich Radiology Academy, Norwich, Norfolk (United Kingdom)

2012-07-15

The aim of this study is to examine the relationship between lumbar lordosis and pars interarticularis fractures. In this retrospective case-control study we compare the angle of lumbar lordosis and the angle of the S1 vertebral endplate (as a measure of pelvic tilt) in patients with bilateral L5 pars interarticularis fractures with age- and sex-matched control cases with normal MRI examinations of the lumbar spine. Twenty-nine cases of bilateral L5 pars interarticularis fractures with matched control-cases were identified on MRI (16 male, 13 female, age 9-63 years). The angle of lordosis was measured between the inferior L4 and superior S1 vertebral endplates on a standing lateral lumbar spine radiograph for both groups. The mean angle of lordosis about the L5 vertebra was 36.9 (SD = 6.5 ) in the pars interarticularis fracture group, and 30.1 (SD = 6.4 ) in the control group. The difference between the two groups was significant (mean difference 6.8 , Student's t test: P < 0.001). The mean angle of sacral tilt measured was 122.2 (SD = 10.16 ) for controls and 136.4 (SD = 10.86 ) for patients with pars defects. The difference in the means of 14.2 was statistically significantly different (P < 0.0001). Sacral tilt represented by a steeply angled superior endplate of S1 is associated with a significantly increased angle of lordosis, between L4 and S1, and pars fractures at L5. Steep angulation of the first sacral vertebral segment maybe the predisposing biomechanical factor that leads to pincer-like impingement of the pars interarticularis and then spondylolysis. (orig.)

Lumbar lordosis and pars interarticularis fractures: a case-control study

Energy Technology Data Exchange (ETDEWEB)

Bugg, William G.; Lewis, Mark; Juette, Arne; Cahir, John G.; Toms, Andoni P. [Cotman Centre, Norwich Radiology Academy, Norwich, Norfolk (United Kingdom)

2012-07-15

The aim of this study is to examine the relationship between lumbar lordosis and pars interarticularis fractures. In this retrospective case-control study we compare the angle of lumbar lordosis and the angle of the S1 vertebral endplate (as a measure of pelvic tilt) in patients with bilateral L5 pars interarticularis fractures with age- and sex-matched control cases with normal MRI examinations of the lumbar spine. Twenty-nine cases of bilateral L5 pars interarticularis fractures with matched control-cases were identified on MRI (16 male, 13 female, age 9-63 years). The angle of lordosis was measured between the inferior L4 and superior S1 vertebral endplates on a standing lateral lumbar spine radiograph for both groups. The mean angle of lordosis about the L5 vertebra was 36.9 (SD = 6.5 ) in the pars interarticularis fracture group, and 30.1 (SD = 6.4 ) in the control group. The difference between the two groups was significant (mean difference 6.8 , Student's t test: P < 0.001). The mean angle of sacral tilt measured was 122.2 (SD = 10.16 ) for controls and 136.4 (SD = 10.86 ) for patients with pars defects. The difference in the means of 14.2 was statistically significantly different (P < 0.0001). Sacral tilt represented by a steeply angled superior endplate of S1 is associated with a significantly increased angle of lordosis, between L4 and S1, and pars fractures at L5. Steep angulation of the first sacral vertebral segment maybe the predisposing biomechanical factor that leads to pincer-like impingement of the pars interarticularis and then spondylolysis. (orig.)

Croissance epitaxiale de GaAs sur substrats de Ge par epitaxie par faisceaux chimiques

Science.gov (United States)

Belanger, Simon

La situation energetique et les enjeux environnementaux auxquels la societe est confrontee entrainent un interet grandissant pour la production d'electricite a partir de l'energie solaire. Parmi les technologies actuellement disponibles, la filiere du photovoltaique a concentrateur solaire (CPV pour concentrator photovoltaics) possede un rendement superieur et mi potentiel interessant a condition que ses couts de production soient competitifs. La methode d'epitaxie par faisceaux chimiques (CBE pour chemical beam epitaxy) possede plusieurs caracteristiques qui la rendent interessante pour la production a grande echelle de cellules photovoltaiques a jonctions multiples a base de semi-conducteurs III-V. Ce type de cellule possede la meilleure efficacite atteinte a ce jour et est utilise sur les satellites et les systemes photovoltaiques a concentrateur solaire (CPV) les plus efficaces. Une des principales forces de la technique CBE se trouve dans son potentiel d'efficacite d'utilisation des materiaux source qui est superieur a celui de la technique d'epitaxie qui est couramment utilisee pour la production a grande echelle de ces cellules. Ce memoire de maitrise presente les travaux effectues dans le but d'evaluer le potentiel de la technique CBE pour realiser la croissance de couches de GaAs sur des substrats de Ge. Cette croissance constitue la premiere etape de fabrication de nombreux modeles de cellules solaires a haute performance decrites plus haut. La realisation de ce projet a necessite le developpement d'un procede de preparation de surface pour les substrats de germanium, la realisation de nombreuses sceances de croissance epitaxiale et la caracterisation des materiaux obtenus par microscopie optique, microscopie a force atomique (AFM), diffraction des rayons-X a haute resolution (HRXRD), microscopie electronique a transmission (TEM), photoluminescence a basse temperature (LTPL) et spectrometrie de masse des ions secondaires (SIMS). Les experiences ont permis

Bimodal electric tissue ablation (BETA) - in-vivo evaluation of the effect of applying direct current before and during radiofrequency ablation of porcine liver

International Nuclear Information System (INIS)

Cockburn, J.F.; Maddern, G.J.; Wemyss-Holden, S.A.

2007-01-01

Aim: To examine the effect of applying increasing amounts of direct current (DC) before and during alternating current radiofrequency ablation of porcine liver. Materials and methods: Using a Radiotherapeutics RF3000 generator, a 9 V AC/DC transformer and a 16 G plain aluminium tube as an electrode, a control group of 24 porcine hepatic radiofrequency ablation zones was compared with 24 zones created using a bimodal electric tissue ablation (BETA) technique in three pigs. All ablations were terminated when tissue impedance rose to greater than 999 Ω or radiofrequency energy input fell below 5 W on three successive measurements taken at 1 min intervals. BETA ablations were performed in two phases: an initial phase of variable duration DC followed by a second phase during which standard radiofrequency ablation was applied simultaneously with DC. During this second phase, radiofrequency power input was regulated by the feedback circuitry of the RF3000 generator according to changes in tissue impedance. The diameters (mm) of each ablation zone were measured by two observers in two planes perpendicular to the plane of needle insertion. The mean short axis diameter of each ablation zone was subjected to statistical analysis. Results: With increased duration of prior application of DC, there was a progressive increase in the diameter of the ablation zone (p < 0.001). This effect increased sharply up to 300 s of pre-treatment after which a further increase in diameter occurred, but at a much lesser rate. A maximum ablation zone diameter of 32 mm was produced (control diameters 10-13 mm). Conclusion: Applying a 9 V DC to porcine liver in vivo, and continuing this DC application during subsequent radiofrequency ablation, results in larger ablation zone diameters compared with radiofrequency ablation alone

Bi-modal radiofrequency treatment for coexisting neuralgia and neuropathy in adjacent divisions of the trigeminal nerve.

Science.gov (United States)

Bhatjiwale, M; Bhatjiwale, M; Naik, L D; Chopade, P

2018-05-29

Trigeminal neuralgia and deafferentation neuropathic pain, or trigeminal neuropathy, are different symptomatologies, rarely reported to present together. The case of a 65-year-old gentleman suffering from trigeminal neuralgia of the maxillary and mandibular division is reported. He first underwent an infraorbital neurectomy that was complicated by deafferentation neuropathic pain, whilst his mandibular neuralgia continued. He was treated successfully for both the neuropathic and neuralgic symptoms in the same session using ultra-extended euthermic pulsed radiofrequency treatment for the maxillary division (V2) and radiofrequency thermocoagulation for the mandibular division (V3). This report is novel in describing the use of dual modalities in the same session for two distinct coexisting clinical entities in two different divisions of the same cranial nerve. The use of ultra-extended pulsed radiofrequency treatment for neuropathic pain in this case is also unique. Nearly 2years after the procedure, the patient continues to have complete pain relief. Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Numerical research of a 2D axial symmetry hybrid model for the radio-frequency ion thruster

Science.gov (United States)

Chenchen, WU; Xinfeng, SUN; Zuo, GU; Yanhui, JIA

2018-04-01

Since the high efficiency discharge is critical to the radio-frequency ion thruster (RIT), a 2D axial symmetry hybrid model has been developed to study the plasma evolution of RIT. The fluid method and the drift energy correction of the electron energy distribution function (EEDF) are applied to the analysis of the RIT discharge. In the meantime, the PIC-MCC method is used to investigate the ion beam current extraction character for the plasma plume region. The beam current simulation results, with the hybrid model, agree well with the experimental results, and the error is lower than 11%, which shows the validity of the model. The further study shows there is an optimal ratio for the radio-frequency (RF) power and the beam current extraction power under the fixed RIT configuration. And the beam extraction efficiency will decrease when the discharge efficiency beyond a certain threshold (about 87 W). As the input parameters of the hybrid model are all the design values, it can be directly used to the optimum design for other kinds of RITs and radio-frequency ion sources.

Manual B-mode versus automated radio-frequency carotid intima-media thickness measurements

NARCIS (Netherlands)

Dogan, Soner; Plantinga, Yvonne; Dijk, Joke M.; van der Graaf, Yolanda; Grobbee, Diederick E.; Bots, Michiel L.; Algra, N. N.; Doevendans, P. A.; Eikelboom, C.; van der Graaf, Y.; Grobbee, E.; Kappelle, L. J.; Mali, W. P. Th M.; Moll, F. L.; Rutten, G. E. H. M.; Visseren, F. L. J.

2009-01-01

Carotid intima-media thickness (CIMT) serves as an indicator of atherosclerosis and cardiovascular risk. Manual measurements of B-mode ultrasound images are the most applied method. Automated measurements with radiofrequency (RF) ultrasound have been suggested as an alternative. The aim of this

LAPAROSCOPIC NEPHRECTOMY USING RADIOFREQUENCY THERMAL ABLATION

Directory of Open Access Journals (Sweden)

B. Ya. Alekseev

2012-01-01

Full Text Available The wide use of current diagnostic techniques, such as ultrasound study, computed tomography, and magnetic resonance imaging, has led to significantly increased detection rates for disease in its early stages. This gave rise to a change in the standards for the treatment of locally advanced renal cell carcinoma (RCC. Laparoscopic nephrectomy (LN has recently become the standard treatment of locally advanced RCC in the clinics having much experience with laparoscopic surgery. The chief drawback of LN is difficulties in maintaining intraoperative hemostasis and a need for creating renal tissue ischemia. The paper gives the intermediate results of application of the new procedure of LN using radiofrequency thermal ablation in patients with non-ischemic early-stage RCC.

Optical generation of radio-frequency power

International Nuclear Information System (INIS)

Hietala, V.M.; Vawter, G.A.; Brennan, T.M.; Hammons, B.E.; Meyer, W.J.

1994-11-01

An optical technique for high-power radio-frequency (RF) signal generation is described. The technique uses a unique photodetector based on a traveling-wave design driven by an appropriately modulated light source. The traveling-wave photodetector (TWPD) exhibits simultaneously a theoretical quantum efficiency approaching 100 % and a very large electrical bandwidth. Additionally, it is capable of dissipating the high-power levels required for the RF generation technique. The modulated light source is formed by either the beating together of two lasers or by the direct modulation of a light source. A system example is given which predicts RF power levels of 100's of mW's at millimeter wave frequencies with a theoretical ''wall-plug'' efficiency approaching 34%

ParTIES: a toolbox for Paramecium interspersed DNA elimination studies.

Science.gov (United States)

Denby Wilkes, Cyril; Arnaiz, Olivier; Sperling, Linda

2016-02-15

Developmental DNA elimination occurs in a wide variety of multicellular organisms, but ciliates are the only single-celled eukaryotes in which this phenomenon has been reported. Despite considerable interest in ciliates as models for DNA elimination, no standard methods for identification and characterization of the eliminated sequences are currently available. We present the Paramecium Toolbox for Interspersed DNA Elimination Studies (ParTIES), designed for Paramecium species, that (i) identifies eliminated sequences, (ii) measures their presence in a sequencing sample and (iii) detects rare elimination polymorphisms. ParTIES is multi-threaded Perl software available at https://github.com/oarnaiz/ParTIES. ParTIES is distributed under the GNU General Public Licence v3. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

The efficacy of conventional radiofrequency denervation in patients with chronic low back pain originating from the facet joints: a meta-analysis of randomized controlled trials.

Science.gov (United States)

Lee, Chang-Hyun; Chung, Chun Kee; Kim, Chi Heon

2017-11-01

Radiofrequency denervation is commonly used for the treatment of chronic facet joint pain that has been refractory to more conservative treatments, although the evidence supporting this treatment has been controversial. We aimed to elucidate the precise effects of radiofrequency denervation in patients with low back pain originating from the facet joints relative to those obtained using control treatments, with particular attention to consistency in the denervation protocol. A meta-analysis of randomized controlled trials was carried out. Adult patients undergoing radiofrequency denervation or control treatments (sham or epidural block) for facet joint disease of the lumbar spine comprised the patient sample. Visual analog scale (VAS) pain scores were measured and stratified by response of diagnostic block procedures. We searched PubMed, Embase, Web of Science, and the Cochrane Database for randomized controlled trials regarding radiofrequency denervation and control treatments for back pain. Changes in VAS pain scores of the radiofrequency group were compared with those of the control group as well as the minimal clinically important difference (MCID) for back pain VAS. Meta-regression model was developed to evaluate the effect of radiofrequency treatment according to responses of diagnostic block while controlling for other variables. We then calculated mean differences and 95% confidence intervals (CIs) using random-effects models. We included data from seven trials involving 454 patients who had undergone radiofrequency denervation (231 patients) and control treatments such as sham or epidural block procedures (223 patients). The radiofrequency group exhibited significantly greater improvements in back pain score when compared with the control group for 1-year follow-up. Although the average improvement in VAS scores exceeded the MCID, the lower limit of the 95% CI encompassed the MCID. A subgroup of patients who responded very well to diagnostic block

Effect of simvastatin and ezetimibe on suPAR levels and outcomes

DEFF Research Database (Denmark)

Hodges, Gethin W; Bang, Casper N; Forman, Julie L

2018-01-01

-lowering therapy also lowers suPAR levels is unknown. METHODS: We investigated whether treatment with Simvastatin 40 mg and Ezetimibe 10 mg lowered plasma suPAR levels in 1838 patients with mild-moderate, asymptomatic aortic stenosis, included in the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study, using...... and Ezetimibe treatment impeded the progression of the time-related increase in plasma suPAR levels. Year-1 suPAR was associated with all-cause mortality, MCE, and AVE irrespective of baseline levels (SEAS study: NCT00092677)....... cardiovascular events (MCE) composed of ischemic cardiovascular events (ICE) and aortic valve related events (AVE). RESULTS: After 4.3 years of follow-up, suPAR levels had increased by 9.2% (95% confidence interval [CI]: 7.0%-11.5%) in the placebo group, but only by 4.1% (1.9%-6.2%) in the group with lipid...

CT-guided percutaneous radiofrequency denervation of the sacroiliac joint

Energy Technology Data Exchange (ETDEWEB)

Gevargez, A.; Schirp, S.; Braun, M. [Department of Radiology and Microtherapy, University of Witten/Herdecke, Bochum (Germany); Groenemeyer, D. [Department of Radiology and Microtherapy, University of Witten/Herdecke, Bochum (Germany); EFMT Development and Research Center for Microtherapy, Bochum (Germany)

2002-06-01

Defining the origin of low back pain is a challenging task. Among a variety of factors the sacroiliac joint (SIJ) is a possible pain generator, although precise diagnosis is difficult. Joint blocks may reduce pain, but are, in cases, of only temporary effect. This study was conducted to evaluate CT-guided percutaneous radiofrequency denervation of the sacroiliac joint in patients with low back pain. The procedure was performed on 38 patients who only temporarily responded to CT-guided SIJ blocks. The denervation was carried out in the posterior interosseous sacroiliac ligaments and on the dorsal rami of the fifth spinal nerve. All interventions were carried out under CT guidance as out-patient therapies. Three months after the therapy, 13 patients (34.2%) were completely free of pain. Twelve patients (31.6%) reported on a substantial pain reduction, 7 patients (18.4%) had obtained a slight and 3 patients (7.9%) no pain reduction. The data of 3 patients (7.9%) was missing. There were no intra- or postoperative complications. Computed tomography-guided percutaneous radiofrequency denervation of the sacroiliac joint appears safe and effective. The procedure may be a useful therapeutic modality, especially in patients with chronic low back pain, who only temporarily respond to therapeutic blocks. (orig.)

CT-guided percutaneous radiofrequency denervation of the sacroiliac joint

International Nuclear Information System (INIS)

Gevargez, A.; Schirp, S.; Braun, M.; Groenemeyer, D.

2002-01-01

Defining the origin of low back pain is a challenging task. Among a variety of factors the sacroiliac joint (SIJ) is a possible pain generator, although precise diagnosis is difficult. Joint blocks may reduce pain, but are, in cases, of only temporary effect. This study was conducted to evaluate CT-guided percutaneous radiofrequency denervation of the sacroiliac joint in patients with low back pain. The procedure was performed on 38 patients who only temporarily responded to CT-guided SIJ blocks. The denervation was carried out in the posterior interosseous sacroiliac ligaments and on the dorsal rami of the fifth spinal nerve. All interventions were carried out under CT guidance as out-patient therapies. Three months after the therapy, 13 patients (34.2%) were completely free of pain. Twelve patients (31.6%) reported on a substantial pain reduction, 7 patients (18.4%) had obtained a slight and 3 patients (7.9%) no pain reduction. The data of 3 patients (7.9%) was missing. There were no intra- or postoperative complications. Computed tomography-guided percutaneous radiofrequency denervation of the sacroiliac joint appears safe and effective. The procedure may be a useful therapeutic modality, especially in patients with chronic low back pain, who only temporarily respond to therapeutic blocks. (orig.)

Study of electronic field emission from large surfaces under static operating conditions and hyper-frequency; Etude de l'emision electronique par effet de champ sur des surfaces larges en regime statique et hyperfrequence

Energy Technology Data Exchange (ETDEWEB)

Luong, M

1997-09-01

The enhanced electronic field emission from large area metallic surfaces lowers performances of industrial devices that have to sustain high electric field under vacuum. Despite of numerous investigations in the past, the mechanisms of such an emission have never been well clarified. Recently, research in our laboratory has pointed out the importance played by conducting sites (particles and protrusions). A refined geometrical model, called superposed protrusions model has been proposed to explain the enhanced emission by local field enhancement. As a logical continuation, the present work aims at testing this model and, in the same time, investigating the means to suppress the emission where it is undesirable. Thus, we have showed: the cause of current fluctuations in a continuous field regime (DC), the identity of emission characteristics ({beta}, A{sub e}) in both radiofrequency (RF) and DC regimes, the effectiveness of a thermal treatment by extern high density electronic bombardment, the effectiveness of a mechanical treatment by high pressure rinsing with ultra pure water, the mechanisms and limits of an in situ RF processing. Furthermore, the electronic emission from insulating particles has also been studied concurrently with a spectral analysis of the associated luminous emission. Finally, the refined geometrical model for conducting sites is reinforced while another model is proposed for some insulating sites. Several emission suppressing treatments has been explored and validated. At last, the characteristic of a RF pulsed field emitted electron beam has been checked for the first time as a possible application of such a field emission. (author)

Radiofrequency fields in our surroundings; Radiofrekvente felt i vaare omgivelser

Energy Technology Data Exchange (ETDEWEB)

2011-07-01

In 2010, the National Radiation Protection Authority (NRPA) with the Post and Telecommunications Authority carried out a project where it is measured radiofrequency fields from various telecom systems in homes, kindergartens, schools, offices, and urban environments. Close to 99 percent of the measurement points were found values of less than one thousandth of the maximum. No values were near the limits. (AG)

Paracrine Apoptotic Effect of p53 Mediated by Tumor Suppressor Par-4

Directory of Open Access Journals (Sweden)

Ravshan Burikhanov

2014-01-01

Full Text Available The guardian of the genome, p53, is often mutated in cancer and may contribute to therapeutic resistance. Given that p53 is intact and functional in normal tissues, we harnessed its potential to inhibit the growth of p53-deficient cancer cells. Specific activation of p53 in normal fibroblasts selectively induced apoptosis in p53-deficient cancer cells. This paracrine effect was mediated by p53-dependent secretion of the tumor suppressor Par-4. Accordingly, the activation of p53 in normal mice, but not p53−/− or Par-4−/− mice, caused systemic elevation of Par-4, which induced apoptosis of p53-deficient tumor cells. Mechanistically, p53 induced Par-4 secretion by suppressing the expression of its binding partner, UACA, which sequesters Par-4. Thus, normal cells can be empowered by p53 activation to induce Par-4 secretion for the inhibition of therapy-resistant tumors.

Radiofrequency ablation of pancreas and optimal cooling of peripancreatic tissue in an ex-vivo porcine model

Directory of Open Access Journals (Sweden)

Michal Crha

2011-01-01

Full Text Available Radiofrequency ablation is a possible palliative treatment for patients suffering from pancreatic neoplasia. However, radiofrequency-induced damage to the peripancreatic tissues during pancreatic ablation might cause fatal complications. The aim of this experimental ex vivo study on pigs was to verify ablation protocols and evaluate whether or not the cooling of peripancereatic tissues during pancreatic ablation has any benefit for their protection against thermal injury. Radiofrequency ablation was performed on 52 pancreatic specimens obtained from pigs. During each pancreatic ablation, continuous measurements of the temperature in the portal vein and duodenal lumen were performed. Peripancreatic tissues were either not cooled or were cooled by being submerged in 14 °C water, or by a perfusion of the portal vein and duodenum with 14 °C saline. The effects of variation in target temperature of the ablated area (90 °C and 100 °C, duration of ablation (5 and 10 min and the effect of peripancreatic tissues cooling were studied. We proved that optimal radiofrequency ablation of the porcine pancreas can be reached with the temperature of 90  °C for 5 min in the ablated area. The perfusion of the duodenal and portal vein by 14 °C saline was found to be the most effective cooling method for minimizing damage to the walls. Continuous measurement of temperatures in peripancreatic tissues will provide useful feedback to assist in their protection against thermal injury. This therapy could be used in the treatment of pancreatic tumours.

Efficacy and safety of the pars plana clip in the Ahmed valve device inserted via the pars plana in patients with refractory glaucoma

Directory of Open Access Journals (Sweden)

Manuel Diaz-Llopis

2010-05-01

Full Text Available Manuel Diaz-Llopis1,2,3, David Salom1,3, Salvador García-Delpech1,2,3, Patricia Udaondo1,3, Jose Maria Millan3,5, J Fernando Arevalo61Department of Ophthalmology, La Fe University Hospital of Valencia, Valencia, Spain; 2Department of Ophthalmology of the Valencia University, Valencia, Spain; 3Biomedical Network Research Centre on Rare Diseases (CIBERER, Valencia, Spain; 4Catholic University San Vicente Martir, Valencia, Spain; 5Department of Genetics, La Fe University Hospital of Valencia, Valencia, Spain; 6Clinica Oftalmologica Centro Caracas, Retina and VItreous Service, Caracas, DC, VenezuelaPurpose: To evaluate the efficacy and safety of the pars plana clip (PPC in the Ahmed valve tube inserted via the pars plana in patients with secondary refractory glaucomas.Methods: Prospective and interventional case series that included 10 patients with secondary refractory glaucoma. The pars plana vitrectomy and the implant of the modified tube were performed during the same surgery. Control of intraocular pressure (IOP and the development of intra- and postoperative complications were evaluated during the follow-up.Results: Follow-up time was twelve months in all the patients. Control of IOP was achieved in 90% of patients, and 70% needed no antiglaucoma treatment. The complications that occurred were transient hypotony in three cases, choroidal detachment in two cases, and one case of intraocular hemorrhage. No case of tube extrusion or tube kink was observed.Conclusions: Our data suggests that implantation of the Ahmed tube modified with the PPC via the pars plana is safe and effective in patients with secondary refractory glaucomas. Keywords: pars plana clip, Ahmed valve, refractory glaucoma, pars plana vitrectomy

Evaluation of ferromagnetic fluids and suspensions for the site-specific radiofrequency-induced hyperthermia of MX11 sarcoma cells in vitro

Energy Technology Data Exchange (ETDEWEB)

Brusentsov, Nikolai A.; Gogosov, V.V.; Brusentsova, T.N.; Sergeev, A.V.; Jurchenko, N.Y.; Kuznetsov, Anatoly A.; Kuznetsov, Oleg A. E-mail: oleg@louisiana.edu; Shumakov, L.I

2001-07-01

Seventeen different ferromagnetic fluids and suspensions were prepared and evaluated for application in radiofrequency-induced hyperthermia. Specific power absorption rates were measured at 0.88 MHz to range from 0 to 240 W per gram of iron for different preparations. Survival of MX11 cells mixed with ferrofluids and subjected to radiofrequency was much lower than with RF without ferrofluid or ferrofluid alone.

Evaluation of ferromagnetic fluids and suspensions for the site-specific radiofrequency-induced hyperthermia of MX11 sarcoma cells in vitro

International Nuclear Information System (INIS)

Brusentsov, Nikolai A.; Gogosov, V.V.; Brusentsova, T.N.; Sergeev, A.V.; Jurchenko, N.Y.; Kuznetsov, Anatoly A.; Kuznetsov, Oleg A.; Shumakov, L.I.

2001-01-01

Seventeen different ferromagnetic fluids and suspensions were prepared and evaluated for application in radiofrequency-induced hyperthermia. Specific power absorption rates were measured at 0.88 MHz to range from 0 to 240 W per gram of iron for different preparations. Survival of MX11 cells mixed with ferrofluids and subjected to radiofrequency was much lower than with RF without ferrofluid or ferrofluid alone

Effects of GSM modulated radio-frequency electromagnetic radiation on permeability of blood-brain barrier in male & female rats.

Science.gov (United States)

Sırav, Bahriye; Seyhan, Nesrin

2016-09-01

With the increased use of mobile phones, their biological and health effects have become more important. Usage of mobile phones near the head increases the possibility of effects on brain tissue. This study was designed to investigate the possible effects of pulse modulated 900MHz and 1800MHz radio-frequency radiation on the permeability of blood-brain barrier of rats. Study was performed with 6 groups of young adult male and female wistar albino rats. The permeability of blood-brain barrier to intravenously injected evans blue dye was quantitatively examined for both control and radio-frequency radiarion exposed groups. For male groups; Evans blue content in the whole brain was found to be 0.08±0.01mg% in the control, 0.13±0.03mg% in 900MHz exposed and 0.26±0.05mg% in 1800MHz exposed animals. In both male radio-frequency radiation exposed groups, the permeability of blood-brain barrier found to be increased with respect to the controls (pradiation exposure was found more effective on the male animals (p0.01). However 900MHz pulse modulated radio-frequency exposure was found effective on the permeability of blood-brain barrier of female animals. Results have shown that 20min pulse modulated radio-frequency radiation exposure of 900MHz and 1800MHz induces an effect and increases the permeability of blood-brain barrier of male rats. For females, 900MHz was found effective and it could be concluded that this result may due to the physiological differences between female and male animals. The results of this study suggest that mobile phone radation could lead to increase the permeability of blood-brain barrier under non-thermal exposure levels. More studies are needed to demonstrate the mechanisms of that breakdown. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of solar PAR and UV radiation on tropical biofouling communities

KAUST Repository

Dobretsov, SV

2010-03-08

We investigated the effect of solar ultraviolet radiation (UVR) and photosynthetically active radiation (PAR) on the development of tropical micro- and macrofouling communities for 30 d. The experimental design involved 3 treatments: full spectrum (PAR+UVR), PAR only, and minimal light (reduced PAR and UVR). Terminal restriction fragment length polymorphism analysis demonstrated that different light conditions resulted in the formation of highly different microbial communities. The lowest densities of bacteria were found under the full spectrum treatment, while the lowest densities of diatoms were found in the minimal light treatment. Macrofouling communities consisted of 13 species and differed among light treatments. In the presence of UVR, communities had low species diversity, evenness, and richness, while in minimal light and PAR treatments, communities had high species diversity, evenness, and richness. Similarity percentage (SIMPER) analysis revealed that the tubeworm Hydroides elegans, the alga Ulva (Enteromorpha) sp., and the bivalve Perna viridis were the species responsible for most of the dissimilarities in macrofouling communities among treatments. While densities of H. elegans were similar in the PAR and minimal light treatments, this polychaete had higher growth rates under minimal light conditions. We conclude that UVR and PAR directly control the development of shallow micro- and macrofouling communities by inhibiting the recruitment and growth of sensitive species and promoting the growth of resistant species, but also that these forms of solar radiation influence the surface cues available to competent larvae by altering the development of the microbial community.

Measurement uncertainty in broadband radiofrequency radiation level measurements

Directory of Open Access Journals (Sweden)

Vulević Branislav D.

2014-01-01

Full Text Available For the evaluation of measurement uncertainty in the measurement of broadband radio frequency radiation, in this paper we propose a new approach based on the experience of the authors of the paper with measurements of radiofrequency electric field levels conducted in residential areas of Belgrade and over 35 municipalities in Serbia. The main objective of the paper is to present practical solutions in the evaluation of broadband measurement uncertainty for the in-situ RF radiation levels. [Projekat Ministarstva nauke Republike Srbije, br. III43009

Loop radiofrequency coils for clinical magnetic resonance imaging at 7 tesla

NARCIS (Netherlands)

Kraff, O.

2011-01-01

To date, the 7 T magnetic resonance imaging (MRI) scanner remains a pure research system and there is still a long way ahead till full clinical integration. Key challenges are the absence of a body transmit radiofrequency (RF) coil as well as of dedicated RF coils in general, short RF wavelengths of

Paternal age related schizophrenia (PARS): Latent subgroups detected by k-means clustering analysis.

Science.gov (United States)

Lee, Hyejoo; Malaspina, Dolores; Ahn, Hongshik; Perrin, Mary; Opler, Mark G; Kleinhaus, Karine; Harlap, Susan; Goetz, Raymond; Antonius, Daniel

2011-05-01

Paternal age related schizophrenia (PARS) has been proposed as a subgroup of schizophrenia with distinct etiology, pathophysiology and symptoms. This study uses a k-means clustering analysis approach to generate hypotheses about differences between PARS and other cases of schizophrenia. We studied PARS (operationally defined as not having any family history of schizophrenia among first and second-degree relatives and fathers' age at birth ≥ 35 years) in a series of schizophrenia cases recruited from a research unit. Data were available on demographic variables, symptoms (Positive and Negative Syndrome Scale; PANSS), cognitive tests (Wechsler Adult Intelligence Scale-Revised; WAIS-R) and olfaction (University of Pennsylvania Smell Identification Test; UPSIT). We conducted a series of k-means clustering analyses to identify clusters of cases containing high concentrations of PARS. Two analyses generated clusters with high concentrations of PARS cases. The first analysis (N=136; PARS=34) revealed a cluster containing 83% PARS cases, in which the patients showed a significant discrepancy between verbal and performance intelligence. The mean paternal and maternal ages were 41 and 33, respectively. The second analysis (N=123; PARS=30) revealed a cluster containing 71% PARS cases, of which 93% were females; the mean age of onset of psychosis, at 17.2, was significantly early. These results strengthen the evidence that PARS cases differ from other patients with schizophrenia. Hypothesis-generating findings suggest that features of PARS may include a discrepancy between verbal and performance intelligence, and in females, an early age of onset. These findings provide a rationale for separating these phenotypes from others in future clinical, genetic and pathophysiologic studies of schizophrenia and in considering responses to treatment. Copyright © 2011 Elsevier B.V. All rights reserved.

Diagrams of ion stability in radio-frequency mass spectrometry

International Nuclear Information System (INIS)

Sudakov, M.Yu.

1994-01-01

For solving radio-frequency mass spectrometry problems and dynamic ion containment are studied and systematized different ways for constructing the ion stability diagrams. A new universal set of parameters is proposed for diagram construction-angular variables, which are the phase raid of ion oscillational motion during positive and negative values of the supplying voltage. An effective analytical method is proposed for optimization of the parameters of the pulsed supplying voltage, in particular its repetition rate

Thermal Ablation for Benign Thyroid Nodules: Radiofrequency and Laser

Energy Technology Data Exchange (ETDEWEB)

Baek, Jung Hwan; Lee, Jeong Hyun [University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Valcavi, Roberto [Endocrinology Division and Thyroid Disease Center, Arcispedale Santa Maria Nuova, Reggio Emilia (Italy); Pacella, Claudio M. [Diagnostic Imaging and Interventional Radiology Department, Ospedale Regina Apostolorum, Albano Laziale-Rome (IT); Rhim, Hyun Chul [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Na, Dong Kyu [Human Medical Imaging and Intervention Center, Seoul (Korea, Republic of)

2011-10-15

Although ethanol ablation has been successfully used to treat cystic thyroid nodules, this procedure is less effective when the thyroid nodules are solid. Radiofrequency (RF) ablation, a newer procedure used to treat malignant liver tumors, has been valuable in the treatment of benign thyroid nodules regardless of the extent of the solid component. This article reviews the basic physics, techniques, applications, results, and complications of thyroid RF ablation, in comparison to laser ablation.

Par Pond vegetation status Summer 1995 -- June survey descriptive summary

International Nuclear Information System (INIS)

Mackey, H.E. Jr.; Riley, R.S.

1995-06-01

The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the shoreline aquatic plant communities in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level, indicated that much of the original plant communities and the intermediate shoreline communities present on the exposed sediments have been lost. The extensive old-field and emergent marsh communities that were present on the exposed shoreline during the drawdown have been flooded and much of the pre-drawdown Par Pond aquatic plant communities have not had sufficient time for re-establishment. The shoreline does, however, have extensive beds of maidencane which extend from the shoreline margin to areas as deep as 2 and perhaps 3 meters. Scattered individual plants of lotus and watershield are common and may indicate likely directions of future wetland development in Par Pond. In addition, within isolated coves, which apparently received ground water seepage and/or stream surface flows during the period of the Par Pond draw down, extensive beds of waterlilies and spike rush are common. Invasion of willow and red maple occurred along the lake shoreline as well. Although not absent from this survey, evidence of the extensive redevelopment of the large cattail and eel grass beds was not observed in this first survey of Par Pond. Future surveys during the growing seasons of 1995, 1996, and 1997 along with the evaluation of satellite date to map the areal extent of the macrophyte beds of Par Pond are planned

Physics of phenomena in the zone close to an underground nuclear explosion; Physique des phenomenes en zone proche des explosions nucleaires souterraines

Energy Technology Data Exchange (ETDEWEB)

Maury, J.; Levret, C. [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

1969-07-01

After a description of the phenomenology of underground explosions, the basic laws governing the propagation in the ground of the energy produced by the explosion are given. The reports considers hydrodynamics, the mechanics of solids, the equations of state for solids and gases in the case of very high and medium pressures, and the dynamical strength of solids. These various elements make it possible to draw up a system of equations which define completely the changes with time of the shock-wave produced in the ground by the explosion. (authors) [French] Apres une description de la phenomenologie des explosions souterraines, on expose les lois fondamentales regissant la propagation dans le sol de l'energie degagee par l'explosion. L'expose comprend des developpements sur l'hydrodynamique, la mecanique des solides, les equations d'etat des solides et des gaz, aux tres fortes et moyennes pressions, et sur la resistance dynamique des solides. Ces differents elements permettent d'ecrire un systeme d'equations qui definissent completement l'evolution dans le temps de l'onde de choc emise dans le sol par l'explosion. (auteurs)

Ablation of hypertrophic septum using radiofrequency energy: an alternative for gradient reduction in patient with hypertrophic obstructive cardiomyopathy?

Science.gov (United States)

Riedlbauchová, Lucie; Janoušek, Jan; Veselka, Josef

2013-06-01

Alcohol septal ablation and surgical myectomy represent accepted therapeutic options for treatment of symptomatic patients with hypertrophic obstructive cardiomyopathy. Long-term experience with radiofrequency ablation of arrhythmogenic substrates raised a question if this technique might be effective for left ventricular outflow tract (LVOT) gradient reduction. We report on a 63-year-old patient with recurrence of symptoms 1 year after alcohol septal ablation (ASA) leading originally to a significant reduction of both symptoms and gradient. Due to a new increase of gradient in the LVOT up to 200 mm Hg with corresponding worsening of symptoms and due to refusal of surgical myectomy by the patient, endocardial radiofrequency ablation of the septal hypertrophy (ERASH) was indicated. Radiofrequency ablation was performed in the LVOT using irrigated-tip ablation catheter; the target site was identified using intracardiac echocardiography and electroanatomical CARTO mapping. ERASH caused an immediate gradient reduction due to hypokinesis of the ablated septum. At 2-month follow-up exam, significant clinical improvement was observed, together with persistent gradient reduction assessed with Doppler echocardiography. Echocardiography and magnetic resonance revealed persistent septal hypokinesis and slight thinning of the ablated region. Septal ablation using radiofrequency energy may be a promising alternative or adjunct to the treatment of hypertrophic obstructive cardiomyopathy. Intracardiac echocardiography and electroanatomical CARTO mapping enable exact lesion placement and preservation of atrioventricular conduction.

Detailed investigation of optoelectronic and microstructural properties of plasma polymerized cyclohexane thin films: Dependence on the radiofrequency power

International Nuclear Information System (INIS)

Manaa, C.; Bouaziz, L.; Lejeune, M.; Zellama, K.; Benlahsen, M.; Kouki, F.; Mejatty, M.; Bouchriha, H.

2015-01-01

Optical properties of polymerized cyclohexane films deposited by radiofrequency plasma enhanced chemical vapor deposition technique at different radiofrequency powers onto glass and silicon substrates, are studied and correlated with the microstructure of the films, using a combination of atomic force microscopy, Raman and Fourier Transformer Infrared spectroscopy and optical measurements. The optical constants such as refractive index n, dielectric permittivity ε and extinction k and absorption α coefficients, are extracted from transmission and reflection spectra through the commercial software CODE. These constants lead, by using common theoretical models as Cauchy, Lorentz, Tauc and single effective oscillator, to the determination of the static refractive index n s and permittivity ε s , the plasma frequency ω p , the carrier density to effective mass ratio N/m e * , the optical conductivity σ oc , the optical band gap E g and the oscillation and dispersion energies E 0 and E d , respectively. We find that n, ε s , ω p , N/m e * , E d , increase with radiofrequency power, while E g and E 0 decrease in the same range of power. These results are well correlated with those obtained from atomic force microscopy, Raman and infrared measurements. They also indicate that the increase of the radiofrequency power promotes the fragmentation of the precursor and increases the carbon C-sp 2 hybridization proportion, which results in an improvement of the optoelectronic properties of the films

[Ambroise Paré, his death and his historians].

Science.gov (United States)

Dumaître, P

2001-01-01

Ambroise Paré died December the 20th., 1590. What happened after his death and what are we knowing about his life? Never forgotten, though a lack of care, we were waiting till the XIXth. century to get recollection upon a subject sustained only by accounts of his travels. After Percy, a surgeon who tried to write Paré's biography through the "Biographie universelle ancienne et moderne, de Michaud (1822)" and some second rank authors, Malgaigne is the first who inside a printing of the "Oeuvres complétes de Paré (1840-41)" has a fine look upon the question, though his work is incomplete and allows many mistakes. Doctors Chéreau and Jal, an historian, analysing civil status records, gave new information enlarged by doctors Le Paulmier, Turner and the U.S. native Janet Doe.

Comparison of wet radiofrequency ablation with dry radiofrequency ablation and radiofrequency ablation using hypertonic saline preinjection: ex vivo bovine liver

International Nuclear Information System (INIS)

Lee, Jeong Min; Han, Joon Koo; Kim, Se Hyung; Lee, Jae Young; Park, Hee Sun; Hur, Hurn; Choi, Byung Ihn; Shin, Kyung Sook

2004-01-01

We wished to compare the in-vitro efficiency of wet radiofrequency (RF) ablation with the efficiency of dry RF ablation and RF ablation with preinjection of NaCl solutions using excised bovine liver. Radiofrequency was applied to excised bovine livers in a monopolar mode for 10 minutes using a 200 W generator and a perfused-cooled electrode with or without injection or slow infusion of NaCl solutions. After placing the perfused-cooled electrode in the explanted liver, 50 ablation zones were created with five different regimens: group A; standard dry RF ablation, group B; RF ablation with 11 mL of 5% NaCl solution preinjection, group C; RF ablation with infusion of 11 mL of 5% NaCl solution at a rate of 1 mL/min, group D; RFA with 6 mL of 36% NaCl solution preinjection, group E; RF ablation with infusion of 6 mL of 36% NaCl solution at a rate of 0.5 mL/min. In groups C and E, infusion of the NaCl solutions was started 1 min before RF ablation and then maintained during RF ablation (wet RF ablation). During RF ablation, we measured the tissue temperature at 15 mm from the electrode. The dimensions of the ablation zones and changes in impedance, current and liver temperature during RF ablation were then compared between the groups. With injection or infusion of NaCl solutions, the mean initial tissue impedance prior to RF ablation was significantly less in groups B, C, D, and E (43-75 Ω) than for group A (80 Ω) (ρ 3 in group A; 12.4 ± 3.8 cm 3 in group B; 80.9 ± 9.9 cm 3 in group C; 45.3 ± 11.3 cm 3 in group D and 81.6 ± 8.6 cm 3 in group E. The tissue temperature measured at 15 mm from the electrode was higher in groups C, D and E than other groups (ρ < 0.05): 53 ± 12 .deg. C in group A, 42 ± 2 .deg. C in group B, 93 ± 8 .deg. C in group C; 79 ± 12 .deg. C in group D and 83 ± 8 .deg.C in group E. Wet RF ablation with 5% or 36% NaCl solutions shows better efficiency in creating a large ablation zone than does dry RF ablation or RF ablation with

Use of radiofrequency in cosmetic dermatology: focus on nonablative treatment of acne scars

Directory of Open Access Journals (Sweden)

Simmons BJ

2014-12-01

Full Text Available Brian J Simmons, Robert D Griffith, Leyre A Falto-Aizpurua, Keyvan Nouri Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, University of Miami, Miami, FL, USA Abstract: Acne is a common affliction among many teens and some adults that usually resolves over time. However, the severe sequela of acne scarring can lead to long-term psychological and psychiatric problems. There exists a multitude of modalities to treat acne scars such as more invasive surgical techniques, subcision, chemical peels, ablative lasers, fractional lasers, etc. A more recent technique for the treatment of acne scars is nonablative radiofrequency (RF that works by passing a current through the dermis at a preset depth to produce small thermal wounds in the dermis which, in turn, stimulates dermal remodeling to produce new collagen and soften scar defects. This review article demonstrates that out of all RF modalities, microneedle bipolar RF and fractional bipolar RF treatments offers the best results for acne scarring. An improvement of 25%–75% can be expected after three to four treatment sessions using one to two passes per session. Treatment results are optimal approximately 3 months after final treatment. Common side effects can include transient pain, erythema, and scabbing. Further studies are needed to determine what RF treatment modalities work best for specific scar subtypes, so that further optimization of RF treatments for acne scars can be determined. Keywords: acne scarring, radiofrequency treatments, nonablative radiofrequency treatments, scars

Bacterial mitosis: Partitioning protein ParA oscillates in spiral-shaped structures and positions plasmids at mid-cell

DEFF Research Database (Denmark)

Ebersbach, G.; Gerdes, Kenn

2004-01-01

The par2 locus of Escherichia coli plasmid pB171 encodes oscillating ATPase ParA, DNA binding protein ParB and two cis-acting DNA regions to which ParB binds (parC1 and parC2). Three independent techniques were used to investigate the subcellular localization of plasmids carrying par2. In cells......A-GFP oscillated in spiral-shaped structures. Amino acid substitutions in ParA simultaneously abolished ParA spiral formation, oscillation and either plasmid localization or plasmid separation at mid-cell. Therefore, our results suggest that ParA spirals position plasmids at the middle of the bacterial nucleoid...

Effect of the Size of the Left Atrium on Sustained Sinus Rhythm in Patients Undergoing Mitral Valve Surgery and Concomitant Bipolar Radiofrequency Ablation for Atrial Fibrillation.

Science.gov (United States)

Avdagić, Harun; Sijerčić Avdagić, Selma; Pirić Avdagić, Melika; Antonič, Miha

2017-12-01

Atrial fibrillation is associated with systemic embolization and complications due to anticoagulant therapy. Radiofrequency ablation has been established as an effective and safe method for the treatment of atrial fibrillation. The aim of this study was to evaluate the effect of the size of the left atrium on the outcome of surgical radiofrequency ablation. Forty patients scheduled for elective mitral valve surgery and radiofrequency ablation were enrolled in the study. Group 1 consisted of patients with a left atrium diameter ≤5 cm and group 2 of patients with left atrium diameter >5 cm. The primary endpoint of the study was stable sinus rhythm 6 months postoperatively. At 6 months postoperatively, sinus rhythm was present in significantly more group 1 patients as compared with group 2 patients, i.e. 15 (75%) vs. 8 (40%), p=0.025. Multivariate analysis proved the size of the left atrium to be an independent predictor of the radiofrequency ablation outcome. Accordingly, the size of the left atrium was demonstrated to be an important predictor of the outcome of radiofrequency ablation for atrial fibrillation. A lower cut-off value of surgical reduction of the atria than previously reported should be considered in order to improve the radiofrequency ablation outcome.

Radiofrequency ablation vs. surgery for perivascular hepatocellular carcinoma: Propensity score analyses of long-term outcomes.

Science.gov (United States)

Lee, Sunyoung; Kang, Tae Wook; Cha, Dong Ik; Song, Kyoung Doo; Lee, Min Woo; Rhim, Hyunchul; Lim, Hyo Keun; Sinn, Dong Hyun; Kim, Jong Man; Kim, Kyunga

2018-07-01

The therapeutic outcomes of surgical resection (SR) or radiofrequency ablation (RFA) for perivascular hepatocellular carcinoma (HCC) have not been compared. The aim of this study was to compare SR with RFA as first-line treatment in patients with perivascular HCC and to evaluate the long-term outcomes of both therapies. This retrospective study was approved by the institutional review board. The requirement for informed consent was waived. Between January 2006 and December 2010, a total of 283 consecutive patients with small perivascular HCCs (≤3 cm, Barcelona Clinic Liver Cancer stage 0 or A) underwent SR (n = 182) or RFA (n = 101) as a first-line treatment. The progression-free survival (PFS) and overall survival (OS) rates were compared by propensity score matching. Subgroup analysis of these outcomes was conducted according to the type of hepatic vessels. The median follow-up was 7.8 years. Matching yielded 62 pairs of patients. In the two matched groups, the PFS rates at 5 and 10 years were 58.0% and 17.8%, respectively, in the SR group, and 25.4% and 14.1%, respectively, in the RFA group (p radiofrequency ablation are both treatment options for perivascular hepatocellular carcinoma. We compared outcomes in patients treated with either method. Surgical resection provided better long-term tumor control and overall survival than radiofrequency ablation for patients with a small perivascular hepatocellular carcinoma (≤3 cm) as a first-line treatment, particularly for periportal tumors. The location of the tumor and the type of peritumoral hepatic vessels need to be considered when choosing between surgical resection and radiofrequency ablation for small HCCs. Copyright © 2018 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Use of radiofrequency ablation in benign thyroid nodules: a literature review and updates.

Science.gov (United States)

Wong, Kai-Pun; Lang, Brian Hung-Hin

2013-01-01

Successful thermal ablation using radiofrequency has been reported in various tumors including liver or kidney tumors. Nonsurgical minimally invasive ablative therapy such as radiofrequency ablation (RFA) has been reported to be a safe and efficient treatment option in managing symptomatic cold thyroid nodules or hyperfunctioning thyroid nodules. Pressure and cosmetic symptoms have been shown to be significantly improved both in the short and long terms after RFA. For hyperfunctioning thyroid nodules, RFA is indicated for whom surgery or radioiodine are not indicated or ineffective or for those who refuse surgery or radio-iodine. Improvement of thyroid function with decreased need for antithyroid medications has been reported. Complication rate is relatively low. By reviewing the current literature, we reported its efficacy and complications and compared the efficacy of RFA relative to other ablative options such as ethanol ablation and laser ablation.

Use of Radiofrequency Ablation in Benign Thyroid Nodules: A Literature Review and Updates

Directory of Open Access Journals (Sweden)

Kai-Pun Wong

2013-01-01

Full Text Available Successful thermal ablation using radiofrequency has been reported in various tumors including liver or kidney tumors. Nonsurgical minimally invasive ablative therapy such as radiofrequency ablation (RFA has been reported to be a safe and efficient treatment option in managing symptomatic cold thyroid nodules or hyperfunctioning thyroid nodules. Pressure and cosmetic symptoms have been shown to be significantly improved both in the short and long terms after RFA. For hyperfunctioning thyroid nodules, RFA is indicated for whom surgery or radioiodine are not indicated or ineffective or for those who refuse surgery or radio-iodine. Improvement of thyroid function with decreased need for antithyroid medications has been reported. Complication rate is relatively low. By reviewing the current literature, we reported its efficacy and complications and compared the efficacy of RFA relative to other ablative options such as ethanol ablation and laser ablation.

TMS suppression of right pars triangularis, but not pars opercularis, improves naming in aphasia

Science.gov (United States)

Naeser, Margaret A.; Martin, Paula I.; Theoret, Hugo; Kobayashi, Masahito; Fregni, Felipe; Nicholas, Marjorie; Tormos, Jose M.; Steven, Megan S.; Baker, Errol H.; Pascual-Leone, Alvaro

2011-01-01

This study sought to discover if an optimum 1 cm2 area in the non-damaged right hemisphere (RH) was present, which could temporarily improve naming in chronic, nonfluent aphasia patients when suppressed with repetitive transcranial magnetic stimulation (rTMS). Ten minutes of slow, 1 Hz rTMS was applied to suppress different RH ROIs in eight aphasia cases. Picture naming and response time (RT) were examined before, and immediately after rTMS. In aphasia patients, suppression of right pars triangularis (PTr) led to significant increase in pictures named, and significant decrease in RT. Suppression of right pars opercularis (POp), however, led to significant increase in RT, but no change in number of pictures named. Eight normals named all pictures correctly; similar to aphasia patients, RT significantly decreased following rTMS to suppress right PTr, versus right POp. Differential effects following suppression of right PTr versus right POp suggest different functional roles for these regions. PMID:21864891

Measuring changes of radio-frequency dielectric properties of chicken meat during storage

Science.gov (United States)

Changes in dielectric properties of stored chicken meat were tracked by using a radio-frequency dielectric spectroscopy method. For this purpose, the dielectric properties were measured with an open-ended coaxial-line probe and vector network analyzer over a broad frequency range from 200 MHz to 20...

Novel Percutaneous Radiofrequency Ablation of Portal Vein Tumor Thrombus: Safety and Feasibility

Energy Technology Data Exchange (ETDEWEB)

Mizandari, Malkhaz [High Technology Medical Center, Tbilisi State Medical University (Georgia); Ao, Guokun [The 309 Hospital of People' s Liberation Army, Department on Oncology (China); Zhang Yaojun; Feng Xi [Imperial College London, Department of Surgery and Cancer (United Kingdom); Shen Qiang [The First Minimally Invasive Department of Eastern Hepatobiliary Surgery Hospital (China); Chen Minshan [Cancer Centre of Sun Yat-Sen University, Department of Hepatobiliary Surgery (China); Lau, Wan Yee [Chinese University of Hong Kong, Department of Surgery, Faculty of Medicine (Hong Kong); Nicholls, Joanna; Jiao Long; Habib, Nagy, E-mail: nagy.habib@imperial.ac.uk [Imperial College London, Department of Surgery and Cancer (United Kingdom)

2013-02-15

We report our experience of the safety of partial recanalization of the portal vein using a novel endovascular radiofrequency (RF) catheter for portal vein tumor thrombosis. Six patients with liver cancer and tumor thrombus in the portal vein underwent percutaneous intravascular radiofrequency ablation (RFA) using an endovascular bipolar RF device. A 0.035-inch guidewire was introduced into a tributary of the portal vein and through which a 5G guide catheter was introduced into the main portal vein. After manipulation of the guide catheter over the thrombus under digital subtraction angiography, the endovascular RF device was inserted and activated around the thrombus. There were no observed technique specific complications, such as hemorrhage, vessel perforation, or infection. Post-RFA portography showed partial recanalization of portal vein. RFA of portal vein tumor thrombus in patients with hepatocellular carcinoma is technically feasible and warrants further investigation to assess efficacy compared with current recanalization techniques.

Radiofrequency ablation of accessory pathways in patients with the Wolff-Parkinson-White syndrome: the long-term mortality and risk of atrial fibrillation.

Science.gov (United States)

Borregaard, Rune; Lukac, Peter; Gerdes, Christian; Møller, Dorthe; Mortensen, Peter Thomas; Pedersen, Lars; Nielsen, Jens Cosedis; Jensen, Henrik Kjærulf

2015-01-01

To assess the long-term mortality and occurrence of post-ablation atrial fibrillation in patients undergoing a radiofrequency ablation for the Wolff-Parkinson-White (WPW) syndrome. A retrospective cohort study of patients (N = 362) subjected to radiofrequency ablation of the WPW syndrome at Aarhus University Hospital from 1990 to 2011. A comparison cohort (N = 3619) was generated from the Danish National Board of Health Central Population Registry. We found no significant difference in all-cause mortality when comparing the WPW group with the control group [hazard ratio (HR): 0.77 and confidence interval (CI): 0.47-1.25]. After radiofrequency ablation, the WPW group had a significantly higher risk of atrial fibrillation than the control group (HR: 4.77 and CI: 3.05-7.43). Atrial fibrillation prior to ablation (HR: 4.66 and CI: 2.09-10.41) and age over 50 years (HR: 9.79 and CI: 4.29-22.36) at the time of ablation were independent risk factors for post-ablation atrial fibrillation in the WPW group. Patients with radiofrequency ablation-treated WPW syndrome have a post-ablation mortality that is similar to the background population. The risk of atrial fibrillation remains high after radiofrequency ablation of the WPW syndrome. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

Radiofrequency radiation injures trees around mobile phone base stations.

Science.gov (United States)

Waldmann-Selsam, Cornelia; Balmori-de la Puente, Alfonso; Breunig, Helmut; Balmori, Alfonso

2016-12-01

In the last two decades, the deployment of phone masts around the world has taken place and, for many years, there has been a discussion in the scientific community about the possible environmental impact from mobile phone base stations. Trees have several advantages over animals as experimental subjects and the aim of this study was to verify whether there is a connection between unusual (generally unilateral) tree damage and radiofrequency exposure. To achieve this, a detailed long-term (2006-2015) field monitoring study was performed in the cities of Bamberg and Hallstadt (Germany). During monitoring, observations and photographic recordings of unusual or unexplainable tree damage were taken, alongside the measurement of electromagnetic radiation. In 2015 measurements of RF-EMF (Radiofrequency Electromagnetic Fields) were carried out. A polygon spanning both cities was chosen as the study site, where 144 measurements of the radiofrequency of electromagnetic fields were taken at a height of 1.5m in streets and parks at different locations. By interpolation of the 144 measurement points, we were able to compile an electromagnetic map of the power flux density in Bamberg and Hallstadt. We selected 60 damaged trees, in addition to 30 randomly selected trees and 30 trees in low radiation areas (n=120) in this polygon. The measurements of all trees revealed significant differences between the damaged side facing a phone mast and the opposite side, as well as differences between the exposed side of damaged trees and all other groups of trees in both sides. Thus, we found that side differences in measured values of power flux density corresponded to side differences in damage. The 30 selected trees in low radiation areas (no visual contact to any phone mast and power flux density under 50μW/m 2 ) showed no damage. Statistical analysis demonstrated that electromagnetic radiation from mobile phone masts is harmful for trees. These results are consistent with the fact

Efficacy evaluation of laparoscopy assisted ultrasound guided radiofrequency ablation in the treatment of hepatocellular carcinoma beneath the diaphragm

Directory of Open Access Journals (Sweden)

Song WANG

2017-06-01

Full Text Available Objective To explore the feasibility, safety and efficacy of laparoscopy assisted ultrasound guided radiofrequency ablation (RFA in the treatment of hepatocellular carcinoma (HCC beneath the diaphragm. Methods Twenty- three consecutive patients with solitary HCC beneath the diaphragm were treated by laparoscopy assisted ultrasound guided RFA in the Chinese PLA General Hospital from January 2013 to March 2016. We observed the perioperative complications and followed- up long-term effect. Results All the 23 patients successfully underwent laparoscopy assisted ultrasound guided radiofrequency ablation. No serious complications such as massive hemorrhage, biliary fistula and severe pleural effusion, hemopneumothorax occurred in the patients during perioperative period. CT examination 2-3 days after the operation revealed that the tumor was completely covered by the ablation area. Besides, the survival condition was satisfactory during follow-up period of 9-38 months. Conclusion Laparoscopy-assisted ultrasound-guided radiofrequency ablation is effective and safe for HCC beneath the diaphragm. DOI: 10.11855/j.issn.0577-7402.2017.05.16

Radio-frequency quadrupole: general properties and specific applications

International Nuclear Information System (INIS)

Stokes, R.H.; Crandall, K.R.; Hamm, R.W.

1980-01-01

The radio-frequency quadrupole (RFQ) linac structure is being developed for the acceleration of low-velocity ions. Recent experimental tests have confirmed its expected performance and have led to an increased interest in a wide range of possible applications. The general properties of RFQ accelerators are reviewed and beam dynamics simulation results are presented for their use in a variety of accelerating systems. These include the low-beta sections of the Fusion Materials Irradiation Test Accelerator, a 200-MHz proton linear accelerator, and a xenon accelerator for heavy ion fusion

Measurement and modelling of a radiofrequency micro-thruster

International Nuclear Information System (INIS)

Charles, C; Boswell, R W

2012-01-01

A capacitively coupled radiofrequency (rf) (13.56 MHz) cylindrical argon micro-discharge expanding into a larger glass tube is studied by performing optical and electrical measurements over a pressure range 0.3–5 Torr and a rf power range 5–40 W. Measurements of the axial and radial plasma density profiles at the Paschen minimum near 1.5 Torr are used to develop a global model of the discharge and estimate neutral heating from ion–neutral charge exchange collisions for micro-propulsion applications. (fast track communication)

Role of regional radiofrequency hyperthermia after hepatic artery block in the normal pit liver

International Nuclear Information System (INIS)

Luo Jingwei; Xu Guozhen; Xiong Jinghong; Liu Xiaoyun; Wang Weihu; Li Yexiong

2003-01-01

Objective: To study the temperature difference, tolerated high temperature, pathological changes between normal and blocked hepatic artery in radiofrequency hyperthermia for pig liver. Methods: Mature pig was used with iodine blocked right hepatic artery. Heat of the whole liver was given for 1 hour by SR-1000 radiofrequency hyperthermia with four thermocouple probes to measure the temperature of the right hepatic artery, right and left normal liver and rectum. Results: Temperature of blocked right liver increased by 10.2 degree C from 39.1 degree C to 49.3 degree C as compared with the left liver of which the temperature rose by 6.8 degree C from 39.7 degree C to 46.5 degree C but the temperature of right hepatic artery and rectum rose only by 3.3 degree C, 3.2 degree C respectively. After sacrificing the pig one week later, on lobe exploration, severe necrosis was observed in the right lobe but the left lobe was normal with a clear demarcation between the two lobes. Conclusions: Hepatic arterial iodine embolization potentiates radiofrequency hyperthermia in the liver. Liver with blocked artery showed conspicuous necrosis but liver with normal un-blocked artery was able to tolerate 46.5 degree C. This provides some evidence for the combination of regional hyperthermia and hepatic artery block in the treatment of advanced liver cancer

First-in-human uPAR PET: Imaging of Cancer Aggressiveness

Science.gov (United States)

Persson, Morten; Skovgaard, Dorthe; Brandt-Larsen, Malene; Christensen, Camilla; Madsen, Jacob; Nielsen, Carsten H.; Thurison, Tine; Klausen, Thomas Levin; Holm, Søren; Loft, Annika; Berthelsen, Anne Kiil; Ploug, Michael; Pappot, Helle; Brasso, Klaus; Kroman, Niels; Højgaard, Liselotte; Kjaer, Andreas

2015-01-01

A first-in-human clinical trial with Positron Emission Tomography (PET) imaging of the urokinase-type plasminogen activator receptor (uPAR) in patients with breast, prostate and bladder cancer, is described. uPAR is expressed in many types of human cancers and the expression is predictive of invasion, metastasis and indicates poor prognosis. uPAR PET imaging therefore holds promise to be a new and innovative method for improved cancer diagnosis, staging and individual risk stratification. The uPAR specific peptide AE105 was conjugated to the macrocyclic chelator DOTA and labeled with 64Cu for targeted molecular imaging with PET. The safety, pharmacokinetic, biodistribution profile and radiation dosimetry after a single intravenous dose of 64Cu-DOTA-AE105 were assessed by serial PET and computed tomography (CT) in 4 prostate, 3 breast and 3 bladder cancer patients. Safety assessment with laboratory blood screening tests was performed before and after PET ligand injection. In a subgroup of the patients, the in vivo stability of our targeted PET ligand was determined in collected blood and urine. No adverse or clinically detectable side effects in any of the 10 patients were found. The ligand exhibited good in vivo stability and fast clearance from plasma and tissue compartments by renal excretion. In addition, high uptake in both primary tumor lesions and lymph node metastases was seen and paralleled high uPAR expression in excised tumor tissue. Overall, this first-in-human study therefore provides promising evidence for safe use of 64Cu-DOTA-AE105 for uPAR PET imaging in cancer patients. PMID:26516369

Rat beta-LPH, gamma-LPH and beta-endorphin biosynthesized by isolated cells of pars intermedia and pars distalis

International Nuclear Information System (INIS)

Gianoulakis, C.; Seidah, N.G.; Routhier, R.; Chretien, M.

1980-01-01

Rats pars intermedia cells were incubated for 3 h with the following amino-acids: a) 35 S-methionine and 3 H-phenylalamine; b) 3 H-valine; and c) 3 H-valine and 3 H-lysine. Radioactive gamma-lipotropin, beta-lipotropin and beta-endorphin were purified on carboxy- methyl-cellulose and characterized by polyacrylamide disc gel electrophoresis af pH 4.5, molecular weight estimation and microsequencing. Rat gamma-lipotropin was shown to differ slightly from ovine gamma-lipotropin in its NH 2 -terminal amino acid sequence, in containing no methionine and having phenylalanine at position 6, valine at positions 13 and 27, and lysine at position 20. The same variations were observed in the sequence of rat beta-lipotropin, while rat beta-endorphin was shown to be identical to the ovine beta-endorphin. Following a 3-h pulse of rat pars distalis, the cells were extracted with care to avoid beta-lipotropin degradation by proteolytic enzymes. A peptide was purified and identified to be rat beta-endorphin, thus demonstrating that beta-endorphin is biosynthesized in pars distalis and is not an extraction artifact. (author)

Structural properties of nitrogenated amorphous carbon films: Influence of deposition temperature and radiofrequency discharge power

International Nuclear Information System (INIS)

Lazar, G.; Bouchet-Fabre, B.; Zellama, K.; Clin, M.; Ballutaud, D.; Godet, C.

2008-01-01

The structural properties of nitrogenated amorphous carbon deposited by radiofrequency magnetron sputtering of graphite in pure N 2 plasma are investigated as a function of the substrate temperature and radiofrequency discharge power. The film composition is derived from x-ray photoemission spectroscopy, nuclear reaction analysis and elastic recoil detection measurements and the film microstructure is discussed using infrared, Raman, x-ray photoemission and near edge x-ray absorption fine structure spectroscopic results. At low deposition temperature and low radiofrequency power, the films are soft, porous, and easily contaminated with water vapor and other atmospheric components. The concentration of nitrogen in the films is very large for low deposition temperatures (∼33.6 at. % N at 150 deg. C) but decreases strongly when the synthesis temperature increases (∼15 at. % N at 450 deg. C). With increasing deposition temperature and discharge power values, the main observed effects in amorphous carbon nitride alloys are a loss of nitrogen atoms, a smaller hydrogen and oxygen contamination related to the film densification, an increased order of the aromatic sp 2 phase, and a strong change in the nitrogen distribution within the carbon matrix. Structural changes are well correlated with modifications of the optical and transport properties

Identification of a new epitope in uPAR as a target for the cancer therapeutic monoclonal antibody ATN-658, a structural homolog of the uPAR binding integrin CD11b (αM.

Directory of Open Access Journals (Sweden)

Xiang Xu

Full Text Available The urokinase plasminogen activator receptor (uPAR plays a role in tumor progression and has been proposed as a target for the treatment of cancer. We recently described the development of a novel humanized monoclonal antibody that targets uPAR and has anti-tumor activity in multiple xenograft animal tumor models. This antibody, ATN-658, does not inhibit ligand binding (i.e. uPA and vitronectin to uPAR and its mechanism of action remains unclear. As a first step in understanding the anti-tumor activity of ATN-658, we set out to identify the epitope on uPAR to which ATN-658 binds. Guided by comparisons between primate and human uPAR, epitope mapping studies were performed using several orthogonal techniques. Systematic site directed and alanine scanning mutagenesis identified the region of aa 268-275 of uPAR as the epitope for ATN-658. No known function has previously been attributed to this epitope Structural insights into epitope recognition were obtained from structural studies of the Fab fragment of ATN-658 bound to uPAR. The structure shows that the ATN-658 binds to the DIII domain of uPAR, close to the C-terminus of the receptor, corroborating the epitope mapping results. Intriguingly, when bound to uPAR, the complementarity determining region (CDR regions of ATN-658 closely mimic the binding regions of the integrin CD11b (αM, a previously identified uPAR ligand thought to be involved in leukocyte rolling, migration and complement fixation with no known role in tumor progression of solid tumors. These studies reveal a new functional epitope on uPAR involved in tumor progression and demonstrate a previously unrecognized strategy for the therapeutic targeting of uPAR.

The protein kinase SIK downregulates the polarity protein Par3

DEFF Research Database (Denmark)

Vanlandewijck, Michael; Dadras, Mahsa Shahidi; Lomnytska, Marta

2018-01-01

on Par3. Functionally, this mechanism impacts on tight junction downregulation. Furthermore, SIK contributes to the loss of epithelial polarity and examination of advanced and invasive human cancers of diverse origin displayed high levels of SIK expression and a corresponding low expression of Par3...

Parallel simulation of radio-frequency plasma discharges

International Nuclear Information System (INIS)

Fivaz, M.; Howling, A.; Ruegsegger, L.; Schwarzenbach, W.; Baeumle, B.

1994-01-01

The 1D Particle-In-Cell and Monte Carlo collision code XPDP1 is used to model radio-frequency argon plasma discharges. The code runs faster on a single-user parallel system called MUSIC than on a CRAY-YMP. The low cost of the MUSIC system allows a 24-hours-per-day use and the simulation results are available one to two orders of magnitude quicker than with a super computer shared with other users. The parallelization strategy and its implementation are discussed. Very good agreement is found between simulation results and measurements done in an experimental argon discharge. (author) 2 figs., 3 refs

Quantitative measurement of radiofrequency volumetric tissue reduction by multidetector CT in patients with inferior turbinate hypertrophy.

Science.gov (United States)

Bahadir, Osman; Kosucu, Polat

2012-12-01

To objectively assess the efficacy of radiofrequency thermal ablation of inferior turbinate hypertrophy. Thirty-five patients with nasal obstruction secondary to inferior turbinate hypertrophy were prospectively enrolled. Radiofrequency energy was delivered to four sites in each inferior turbinate. Patients were evaluated before and 8 weeks after intervention. Subjective evaluation of nasal obstruction was performed using a visual analogue scale (VAS), and objective evaluation of the turbinate volume reduction was calculated using multidetector CT. Volumetric measurements of the preoperative inferior turbinate were compared with postoperative values on both sides. The great majority of patients (91.4%) exhibited subjective postoperative improvement. Mean obstruction (VAS) improved significantly from 7.45±1.48 to 3.54±1.96. Significant turbinate volume reduction was achieved by the surgery on both right and left sides [(preoperative vs. postoperative, right: 6.55±1.62cm(3) vs. 5.10±1.47cm(3), (PRadiofrequency is a safe and effective surgical procedure in reducing turbinate volume in patients with inferior turbinate hypertrophy. Multidetector CT is an objective method of assessment in detecting radiofrequency turbinate volume reduction. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

PET imaging of urokinase-type plasminogen activator receptor (uPAR) in prostate cancer

DEFF Research Database (Denmark)

Skovgaard, Dorthe; Persson, Morten; Kjaer, Andreas

2016-01-01

Overexpression of urokinase-type plasminogen activator receptors (uPAR) represents an important biomarker for aggressiveness in most common malignant diseases, including prostate cancer (PC). Accordingly, uPAR expression either assessed directly in malignant PC tissue or assessed directly in plasma...... and prognostic imaging method. In this review, we will focus on the recent development of uPAR PET and the relevance within prostate cancer imaging. Novel antibody and small-molecule radiotracers-targeting uPAR, including a series of uPAR-targeting PET ligands, based on the high affinity peptide ligand AE105......, have been synthesized and tested in vitro and in vivo in preclinical murine xenograft models and, recently, in a first-ever clinical uPAR PET study in cancer patients, including patients with PC. In this phase I study, a high and specific uptake of the tracer 64Cu-DOTA-AE105 was found in both primary...

Dielectric-filled radiofrequency linacs

Energy Technology Data Exchange (ETDEWEB)

Faehl, R J; Keinigs, R K; Pogue, E W [Los Alamos National Lab., NM (United States)

1997-12-31

High current, high brightness electron beam accelerators promise to open up dramatic new applications. Linear induction accelerators are currently viewed as the appropriate technology for these applications. A concept by Humphries and Hwang may permit radiofrequency accelerators to fulfill the same functions with greater simplicity and enhanced flexibility. This concept involves the replacement of vacuum rf cavities with dielectric filled ones. Simple analysis indicates that the resonant frequencies are reduced by a factor of ({epsilon}{sub 0}/{epsilon}){sup 1/2} while the stored energy is increased by {epsilon}/{epsilon}{sub 0}. For a high dielectric constant like water, this factor can approach 80. A series of numerical calculations of simple pill-box cavities was performed. Eigenfunctions and resonant frequencies for a full system configuration, including dielectric material, vacuum beamline, and a ceramic window separating the two have been computed. These calculations are compared with the results of a small experimental cavity which have been constructed and operated. Low power tests show excellent agreement. (author). 4 figs., 8 refs.

[Clinical effect of bipolar radiofrequency thermotherapy on allergic rhinitis].

Science.gov (United States)

Oyake, Daisuke; Ochi, Kentaro; Takatsu, Mitsuharu; Shintani, Toshiharu; Umehara, Tsuyoshi; Koizuka, Izumi

2004-07-01

The clinical effect of bipolar radiofrequency thermotherapy on allergic rhinitis was evaluated. A bipolar radiofrequency system (CelonLab ENT) was used to treat 16 patients suffering from allergic rhinitis between February 2003 and August 2003. The thermotherapy was performed under local anesthesia at the otolaryngology outpatient clinic of St. Marianna University Toyoko Hospital. Data were collected by questionnaire and rhinomanometry preoperatively and 2 months postoperatively. The mean visual analogue scale (VAS) score for intraoperative pain was 31 mm (range, 0-100), and nearly all the patients felt no or a subtle pain during the thermotherapy. Postoperative pain was also well tolerated, with nearly all the patients not requiring analgesic drugs. Postoperative bleeding was minor, and none of the patients required additional treatment for bleeding. Nearly all the patients reported an improvement in their nasal patency, rhinorrhea, headaches, and sleeping. Statistically significant improvements were observed for all the measured VAS scores: nasal patency, rhinorrhea, headache, and olfactory function. Nasal resistance, as measured by anterior rhinomanometry, significantly improved after treatment. The effect of decongestion was also measured using anterior rhinomanometry. The ratio of nasal resistance before and after decongestion was significantly higher after thermotherapy, suggesting that nasal decongestion had a smaller effect on nasal patency after treatment. The current results suggest that the CelonLab ENT device is an effective and safe treatment for allergic rhinitis.

Par3L enhances colorectal cancer cell survival by inhibiting Lkb1/AMPK signaling pathway

International Nuclear Information System (INIS)

Li, Taiyuan; Liu, Dongning; Lei, Xiong; Jiang, Qunguang

2017-01-01

Partitioning defective 3-like protein (Par3L) is a recently identified cell polarity protein that plays an important role in mammary stem cell maintenance. Previously, we showed that high expression of Par3L is associated with poor survival in malignant colorectal cancer (CRC), but the underlying mechanism remained unknown. To this end, we established a Par3L knockout colorectal cancer cell line using the CRISPR/Cas system. Interestingly, reduced proliferation, enhanced cell death and caspase-3 activation were observed in Par3L knockout (KO) cells as compared with wildtype (WT) cells. Consistent with previous studies, we showed that Par3L interacts with a tumor suppressor protein liver kinase B1 (Lkb1). Moreover, Par3L depletion resulted in abnormal activation of Lkb1/AMPK signaling cascade. Knockdown of Lkb1 in these cells could significantly reduce AMPK activity and partially rescue cell death caused by Par3L knockdown. Furthermore, we showed that Par3L KO cells were more sensitive to chemotherapies and irradiation. Together, these results suggest that Par3L is essential for colorectal cancer cell survival by inhibiting Lkb1/AMPK signaling pathway, and is a putative therapeutic target for CRC. - Highlights: • Par3L knockout using the CRISPR/Cas system induces apoptosis in colorectal cancer cells. • Par3L interacts with Lkb1 and regulates the activity of AMPK signaling cascade. • Par3L knockout cells are more sensitive to treatment of different chemotherapy drugs and irradiation.

Radiofrequency ablation versus resection for Barcelona clinic liver cancer very early/early stage hepatocellular carcinoma: a systematic review.

Science.gov (United States)

He, Zhen-Xin; Xiang, Pu; Gong, Jian-Ping; Cheng, Nan-Sheng; Zhang, Wei

2016-01-01

To compare the long-term survival outcomes of radiofrequency ablation and liver resection for single very early/early stage hepatocellular carcinoma (HCC). The Cochrane Library (Issue 3, 2015), Embase (1974 to March 15, 2015), PubMed (1950 to March 15, 2015), Web of Science (1900 to March 15, 2015), and Chinese Biomedical Literature Database (1978 to March 15, 2015) were searched to identify relevant trials. Only trials that compared radiofrequency ablation and liver resection for single very early stage (≤2 cm) or early stage (≤3 cm) HCC according to the Barcelona clinic liver cancer (BCLC) staging system were considered for inclusion in this review. The primary outcomes that we analyzed were the 3-year and 5-year overall survival (OS) rates, and the secondary outcomes that we analyzed were the 3-year and 5-year disease-free survival (DFS) rates. Review Manager 5.3 was used to perform a cumulative meta-analysis. Possible publication bias was examined using a funnel plot. A random-effects model was applied to summarize the various outcomes. Six studies involving 947 patients were identified that compared radiofrequency ablation (n=528) to liver resection (n=419) for single BCLC very early HCC. In these six studies, the rates of 3-year OS, 5-year OS, 3-year DFS, and 5-year DFS were significantly lower in the radiofrequency ablation group than in the liver resection group (risk ratio [RR] =0.90, 95% confidence interval [CI]: 0.83-0.98, P=0.01; RR =0.84, 95% CI: 0.75-0.95, P=0.004; RR =0.77, 95% CI: 0.60-0.98, P=0.04; and RR =0.70, 95% CI: 0.52-0.94, P=0.02, respectively). Ten studies involving 2,501 patients were identified that compared radiofrequency ablation (n=1,476) to liver resection (n=1,025) for single BCLC early HCC. In these ten studies, the rates of 3-year OS, 5-year OS, 3-year DFS, and 5-year DFS were also significantly lower in the radiofrequency ablation group than in the liver resection group (RR =0.93, 95% CI: 0.88-0.98, P=0.003; RR =0.84, 95% CI

Profils des enfants infectes par le vih en debut du traitement ...

African Journals Online (AJOL)

But : Décrire les profils des enfants infectés par le VIH au début du traitement antirétroviral. Matériels et méthode: Les dossiers des enfants infectés par le VIH dans la région maritime ont été analysés de mai 2008 à février 2010 par le comité thérapeutique. Résultats: Parmi les 96 dossiers analysés, 66,67% venaient du ...

Perioperative outcomes of zero ischemia radiofrequency ablation-assisted tumor enucleation for renal cell carcinoma: results of 182 patients.

Science.gov (United States)

Zhang, Chengwei; Zhao, Xiaozhi; Guo, Suhan; Ji, Changwei; Wang, Wei; Guo, Hongqian

2018-05-15

To evaluate the perioperative outcomes of zero ischemia radiofrequency ablation-assisted tumor enucleation. Patients undergoing zero ischemia radiofrequency ablation-assisted tumor enucleation were retrospectively identified from July 2008 to March 2013. The tumor was enucleated after RFA treatment. R.E.N.A.L., PADUA and centrality index (C-index) score systems were used to assess each tumor case. We analyzed the correlation of perioperative outcomes with these scores. Postoperative complications were graded with Clavien-Dindo system. Multivariate logistic regression analyses were used to assess risk of complications. Among 182 patients assessed, median tumor size, estimated blood loss, hospital stay and operative time were 3.2 cm (IQR 2.8-3.4), 80 ml (IQR 50-120), 7 days (IQR 6-8) and 100 min (IQR 90-120), respectively. All three scoring systems were strongly correlated with estimated blood loss, hospital stay and operative time. We found 3 (1.6%) intraoperative and 23 (12.6%, 13 [7.1%] Grade 1 and 10 [5.5%] Grade 2 & 3a) postoperative complications. The median follow-up was 55.5 months (IQR 45-70). Additionally, the complexities of R.E.N.A.L., PADUA and C-index scores were significantly correlated with complication grades (P radiofrequency ablation-assisted tumor enucleation is considered an effective nephron-sparing treatment. Scoring systems could be useful for predicting perioperative outcomes of radiofrequency ablation-assisted tumor enucleation.

Brief communication: Population variation in human maxillary premolar accessory ridges (MxPAR).

Science.gov (United States)

Burnett, Scott E; Hawkey, Diane E; Turner, Christy G

2010-02-01

The purpose of this brief communication is to report the results of an analysis of maxillary premolar accessory ridges (MxPAR), a common but understudied accessory ridge that may occur both mesial and distal to the central ridge of the buccal cusp of upper premolars. We developed a new five-grade scoring plaque to better categorize MxPAR variation. Subsequently, we conducted a population analysis of MxPAR frequency in 749 dental casts of South African Indian, American Chinese, Alaskan Eskimo, Tohono O'odham (Papago), Akimel O'odham (Pima), Solomon Islander, South African Bantu, and both American and South African Whites. Northeast Asian and Asian-derived populations exhibited the highest MxPAR frequencies while Indo-European samples (South African Indians, American and South African Whites) exhibited relatively low frequencies. The Solomon Islanders and South African Bantu samples exhibited intermediate frequencies. Our analysis indicates that statistically significant differences in MxPAR frequency exist between major geographic populations. As a result, the MxPAR plaque has now been added to the Arizona State University Dental Anthropology System, an important contribution as maxillary premolar traits are underrepresented in analyses of dental morphology. 2009 Wiley-Liss, Inc.

Flute Characteristics of and Microwave Emission from a Plasma in a Mirror; Instabilite en Cannelures et Emission de Micro-Ondes par un Plasma dans une Machine a Miroirs; Zhelobkovye kharakteristiki i ehmissiya mikrovoln iz plazmy v zerkale; Caracteristicas del Estriado y Emision de Microondas por un Plasma en un Espejo

Energy Technology Data Exchange (ETDEWEB)

Scott, F. R.; Jensen, T. H.; Wharton, C. B. [General Atomic Division, General Dynamics Corporation, San Diego, CA (United States)

1966-04-15

construit une machine a miroirs puisee pour etudier la stabilite d'un plasma d'energie relativement faible. Le plasma de 70 eV, forme dans un canon, est canalise ven le miroir par un champ de guidage octopolaire lineaire. La duree du champ du miroir est egale au temps de transit du plasma. Les auteurs ont mesure des densites d'electrons de 10{sup 13} cm{sup -3} dans le plan central du miroir. Ils ont observe deux modes distincts de fonctionnement qui ne dependent que des conditions regnant dans le champ de guidage. Dans le premier mode, le plasma dans le miroir ne semble pas presenter d'instabilite en cannelures, la plus grande partie du plasma d'echappe le long de l'axe', on observe une diffusion radiale anormale lente, il se produit une emission de micro-ondes dont les frequences sont des harmoniques de la frequence cyclotronique des electrons dans l'intervalle entre n = 1 et n = 19 au moins. L'emission de micro-ondes n'est pas compatible avec la branche electronique de l'instabilite de Harris. Les auteurs attribuent la stabilite de ce mode a la fixation des lignes de force par le plasma froid diffusant de la region du champ de guidage. Ils ont observe des densites d'electrons superieurs a 10{sup 11} cm{sup 3} pendant 200 {mu}s dans la region situee entre le miroir et le champ de guidage. La presence d'un cylindre de symetrie axiale dans le champ de guidage a pour effet de diminuer cette densite. Des mesures faites dans cette region fournissent des densites inferieures a 10u cm{sup 3}apres 40 {mu}s. Le plasma qui en resulte, piege dans le miroir, presente des instabilites en cannelures, des pertes de plasma radiales, une emission de micro-ondes irreguliere intense, ainsi qu'une decroissance de densite rapide. Les auteurs ont identifie la cannelure m = 1, dont ils ont suivi la phase dans l'angle 4{pi}. La vitesse de phase possede la meme direction que la derive electronique sous l'influence de B. Le signe de cette vitesse de phase peut s'expliquer par la theorie de Krall

Measurements of energetic helium-3 minority distributions during ion cyclotron radiofrequency heating in the Princeton large torus

International Nuclear Information System (INIS)

Hammett, G.W.; Kaita, R.; Wilson, J.R.

1988-01-01

Ion cyclotron radiofrequency heating experiments were performed with a 3 He minority ion species in a 4 He majority plasma in the Princeton Large Torus. The energetic 3 He ion 'tail' was measured directly with a charge exchange neutral analyser for the first time. Comparisons with bounce averaged quasi-linear calculations suggest a modestly peaked radiofrequency power deposition profile. The double charge exchange process 3 He ++ + 4 He o -> 3 He o + 4 He ++ demonstrated in these measurements may be useful as part of an alpha particle diagnostic in a fusion reactor experiment. (author). 21 refs, 4 figs

Bile Duct Disruption Following Radiofrequency Ablation: Successful Repair Using a Covered Stent

International Nuclear Information System (INIS)

Thompson, Philip M.; Hare, Christopher M.B.; Lees, William R.

2004-01-01

Persistent biliary leaks, whether iatrogenic or secondary to malignancy, often present a difficult management problem. Recent reports have suggested a role for covered metallic stents in this context. We describe the successful use of a covered stent to seal a persistent biliary leak following radiofrequency ablation of colorectal liver metastases

Contribution to the study of accelerating structure for electrons and respective radiofrequency couplers

International Nuclear Information System (INIS)

Franco, M.A.R.

1991-01-01

In this work, the experimental results pertaining to the construction and evaluation of a constant gradient accelerating structure and of the radiofrequency couplers are presented. The theoretical methods to determine the initial dimensions of the iris-loaded accelerating structure are presented. The final dimensions have been experimentally determined utilizing four three-cavity sections representing the 4 sup(th), 12 sup(th), 20 sup(th) and 27 sup(th) cavities of the final structure. The diameters of the cavities were corrected for variations of temperature, pressure and humidity. A v sub(p) = c, constant gradient, twelve-cavity prototype of the accelerating structure have been constructed and its principal parameters were experimentally determined according to methods also described in this work. Two prototypes of door-knob type radiofrequency couplers have been constructed and experimental procedures to match and tune the couplers and the accelerating structure were implemented. (author)

Intoxication par la paraphényléne-diamine

African Journals Online (AJOL)

raoul

9 mars 2011 ... remède contre la douleur par Averbukh [8], ou contre la constipation par Schemesh [9], mais l´utilisation à des fins autolytique reste toujours prédominante. Le tableau clinique de l´intoxication à ... une anurie ayant nécessité le recours à l´hémodialyse. Ce taux de survenue d´IRA anurique est relativement ...

Cooling system for the IFMIF-EVEDA radiofrequency system; Sistema de refrigeracion del sistema de radiofrecuencia del IFMIF-EVEDA

Energy Technology Data Exchange (ETDEWEB)

Perez Pichel, G. D.

2012-07-01

The IFMIF-EVEDA project consists on an accelerator prototype that will be installed at Rokkasho (Japan). Through CIEMAT, that is responsible of the development of many systems and components. Empresarios Agrupados get the responsibility of the detailed design of the cooling system for the radiofrequency system (RF system) that must feed the accelerator. the RF water cooling systems is the water primary circuit that provides the required water flow (with a certain temperature, pressure and water quality) and also dissipates the necessary thermal power of all the radiofrequency system equipment. (Author) 4 refs.

Treatment of abdominal cellulite and circumference reduction with radiofrequency and dynamic muscle activation.

Science.gov (United States)

Wanitphakdeedecha, Rungsima; Iamphonrat, Thanawan; Thanomkitti, Kanchalit; Lektrakul, Nittaya; Manuskiatti, Woraphong

2015-01-01

Cellulite is a frequent skin condition for which treatment remains a challenge. A wide variety of treatments are available but most procedures offer suboptimal clinical effect and/or delayed therapeutic outcome. Only few therapeutic options have proven efficacy in the treatment of cellulite. To determine the efficacy and the safety profiles of radiofrequency and dynamic muscle activation technology in treatment of abdominal cellulite and circumference reduction. Twenty-five females with abdominal cellulite received 6 weekly radiofrequency and dynamic muscle activation treatments. Treatment areas included the abdomen and both sides of flanks. Subjects were evaluated using standardized photographs, and measurements of body weight and abdominal circumference at baseline, before every treatment visit, and 1 week and four weeks after the final treatment. Subcutaneous tissue thickness was recorded by ultrasound at baseline and 4 weeks after completion of treatment protocol. Physicians' evaluation and patient's satisfaction of clinical improvement were also measured. All subjects completed the treatment protocol and attended every follow-up visits. There was significant abdominal circumference reduction of 2.96 and 2.52 cm at 1-, and 4-week follow-up visits (p last treatment, the average circumferential reduction was sustained. Most of the patients were rated to have 25-49% improvement at 5th treatment, and 1- and 4-week follow-up visits. Ninety-two percent of the patients were satisfied with the treatment outcome. Radiofrequency provided beneficial effects on the reduction of abdomen and cellulite appearance. The benefit of muscle activation is yet to be determined.

An experimental study on hepatic ablation using an expandable radio-frequency needle electrode

International Nuclear Information System (INIS)

Choi, Dong Il; Lim, Hyo Keun; Park, Jong Min; Kang, Bo Kyung; Woo, Ji Young; Jang, Hyun Jung; Kim, Seung Hoon; Lee, Won Jae; Park, Cheol Keun; Heo, Jin Seok

1999-01-01

The purpose of this study was to determine the factors influencing on the size of thermal lesions after ablation using an expendable radio-frequency needle electrode in porcine liver. Ablation procedures involved the use of a monopolar radio-frequency generator and 15-G needle electrodes with four and seven retractable hooks (RITA Medical System, Mountain View, Cal., U.S.A.). The ablation protocol in fresh porcine liver comprised of combinations of varying hook deployment, highest set temperature, and ablation time. Following ablation, the maximum diameter of all thermal lesions was measured on a longitudinal section of the specimen. Ten representive lesions were examined by an experienced pathologist. At 3-cm hook deployment of the needle electrode with four lateral hooks, the size of spherical thermal lesions increased substantially with increases in the highest set temperature and ablation time until 11 minutes. After 11 minutes lesion size remained similar, with a maximum diameter of 3.3 cm. At 2-cm hook deployment, sizes decreased to about 2/3 of those at 3 cm , and at 1-cm hook deployment lesions were oblong. At 3-cm hook deployment of a needle electrode with seven hooks, the size of thermal lesions increased with increasing ablation time until 14 minutes, and the maximum diameter was 4.1 cm. Microscopic examination showed a wide zone of degeneration and focal coagulation necrosis. The size of thermal lesions produced by the use of an expandable radio-frequency needle electrode were predictable, varying according to degree of hook deployment, highest set temperature, and ablation time

CT-guided radiofrequency ablation of osteoid osteoma using a novel battery-powered drill

Energy Technology Data Exchange (ETDEWEB)

Schnapauff, Dirk; Streitparth, Florian; Wieners, Gero; Collettini, Federico; Hamm, Bernd; Gebauer, Bernhard [Charite Universitaetsmedizin Berlin, Department of Radiology, Berlin (Germany); Joehrens, Korinna [Charite Universitaetsmedizin Berlin, Department of Pathology, Berlin (Germany)

2015-05-01

To evaluate the use of a novel battery-powered drill, enabling specimen requirement while drilling, in radiofrequency ablation of osteoid osteoma as an alternative to conventional orthopedic drills. Between 2009 and 2013, altogether 33 patients underwent CT-guided radiofrequency ablation of an osteoid osteoma at our institution. To access the nidus of the clinically and radiologically suspected osteoid osteoma, a channel was drilled using the OnControl Bone Marrow Biopsy System (OBM, Arrow OnControl, Teleflex, Shavano Park, TX, USA) and a biopsy was taken. Procedure time (i.e., drilling including local anesthesia), amount of scans (i.e., single-shot fluoroscopy), radiation exposure, and the results of biopsy were investigated and compared retrospectively to a classical approach using either a manual bone biopsy system or a conventional orthopedic drill (n = 10) after ethical review board approval. Drilling the tract into the nidus was performed without problems in 22 of the 23 OBM cases. Median procedure time was 7 min compared to 13 min using the classical approach (p < 0.001). Median amount CT scans, performed to control correct positioning of the drill was comparable with 26 compared to 24.5 (p = NS) scans. Histologically, the diagnosis of osteoid osteomas could be determined in all 17 cases where a biopsy was taken. Radiofrequency ablation could be performed without problems in any case. The use of the battery-powered drill was feasible and facilitated the access to the osteoid osteoma's nidus offering the possibility to extract a specimen in the same step. (orig.)

Percutaneous ultrasound-guided radiofrequency ablation for kidney tumors in patients with surgical risk

International Nuclear Information System (INIS)

Salagierski, Marek; Salagierski, Maciej; Sosnowski, Marek; Salagierska-Barwinska, Anna

2006-01-01

The aim of this study was to describe our experience with percutaneous ultrasound-guided radiofrequency ablation of kidney tumors. From July 2002 to August 2005, 45 radiofrequency ablations (RFA) in 42 selected patients with kidney tumor were performed. The patients had either contraindications to surgery procedures or had a solitary kidney. The average tumor size was 37.5 mm (range, 18-59 mm) with the mean age of 68 years (range, 28-83 years). RFA were performed based on radiographic findings. Needle biopsy was made only twice. Monopolar Cool-tip Tyco or bipolar Celon Olympus radiofrequency devices were used. The procedure was performed under conscious sedation with local anesthesia. Treatment efficacy was assessed by computed tomography and by Doppler ultrasound. The absence of contrast enhancement on computed tomography was considered to be a successful treatment. The average follow up was 14 months (range, 3-36 months). In 42 tumors (93%), total absence of contrast enhancement was obtained after the initial RFA and in three tumors (7%) after the second ablation session. There were no complications following 41 procedures, including all ablations in small (<35 mm) renal masses. In four procedures, minor complications were observed. All patients are alive. There has been no need for chronic hemodialysis and, until now, we have not observed any local recurrences with the exception of one metastasis to an ipsilateral adrenal gland. RFA of kidney tumors is a promising alternative treatment which could be considered for patients who are not suitable for surgery. (author)

ECG changes in factory workers exposed to 27.2  MHz radiofrequency radiation.

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Chen, Qingsong; Xu, Guoyong; Lang, Li; Yang, Aichu; Li, Shilin; Yang, Liwen; Li, Chaolin; Huang, Hanlin; Li, Tao

2013-05-01

To research the effect of 27.2 MHz radiofrequency radiation on electrocardiograms (ECG), 225 female workers operating radiofrequency machines at a shoe factory were chosen as the exposure group and 100 female workers without exposure from the same factory were selected as the control group. The 6 min electric field strength that the female workers were exposed to was 64.0 ± 25.2 V/m (mean ± SD), which exceeded 61 V/m, the International Commission on Non-Ionizing Radiation Protection reference root mean square levels for occupational exposure. A statistical difference was observed between the exposed group and the control group in terms of the rate of sinus bradycardia (χ(2)  = 11.48, P = 0.003). When several known risk factors for cardiovascular disease were considered, including smoking, age, alcohol ingestion habit, and so on, the exposure duration was not an effective factor for ECG changes, sinus arrhythmia, or sinus bradycardia according to α = 0.05, while P = 0.052 for sinus arrhythmia was very close to 0.05. We did not find any statistical difference in heart rate, duration of the QRS wave (ventricular depolarization), or corrected QT intervals (between the start of the Q wave and end of the T wave) between the exposed and control groups. Occupational exposure to radiofrequency radiation was not found to be a cause of ECG changes after consideration of the confounding factors. Copyright © 2012 Wiley Periodicals, Inc.

Radiofrequency thermocoagulation of the thoracic splanchnic nerve in functional abdominal pain syndrome -A case report-.

Science.gov (United States)

Choi, Ji-Won; Joo, Eun-Young; Lee, Sang-Hyun; Lee, Chul-Joong; Kim, Tae-Hyeong; Sim, Woo-Seok

2011-07-01

The thoracic splanchnic nerve block has been used in managing abdominal pain, especially for pains arising from abdominal cancers. A 27-year-old male patient who had a constant abdominal pain was referred to our clinic for pain management but had no organic disease. The numeric rating scale (NRS) for pain scored 7/10. We applied a diagnostic thoracic splanchnic nerve block under the diagnosis of functional abdominal pain syndrome. Since the block reduced the pain, we applied a radiofrequency thermocoagulation at the T11 and T12 vertebral level. Thereafter, his symptoms improved markedly with pain decreasing to an NRS score of 2-3/10. Hereby, we report a successful management of functional abdominal pain via radiofrequency thermocoagulation of the thoracic splanchnic nerves.

Image-guided radiofrequency ablation (RFA) of spinal tumors

International Nuclear Information System (INIS)

Gevargez, Athour; Groenemeyer, Dietrich H.W.

2008-01-01

Purpose: To evaluate retrospectively the efficacy and safety of radiofrequency ablation (RFA) in patients with spinal tumors. Materials and methods: Forty-one patients (25 men, 16 women; age range, 46-82 years) with nonresectable primary or secondary tumor involvement of the spine unresponsive to chemo- and radiotherapy received RFA treatment. Two radiofrequency ablation systems, one with a cool-tip electrode and one with an expandable electrode catheter, were used. Both systems work impedance controlled with a power output of 150- 200 W. Each coagulation cycle lasted 12-15 min depending on tumor impedance. Several single RFA cycles of 15 min each were used for overlapping RFAs in tumors with diameters of more than 3 cm. Temperature was kept between 50 deg. C and 120 deg. C and was chosen according to spinal cord distance and patient heat tolerance during the ablation. Multi-slice computed tomography (CT) combined with C-arm fluoroscopy guided the intervention. Efficacy outcomes were assessed after about 6 weeks, 6 months, and more than 6 months using standardized questionnaires and indices regarding tumor pain, pain disability, functional activities, quality of life, neurological status, and tumor progression. Results: RFA significantly reduced tumor-induced pain within 6 weeks, improved daily activities, and maintained quality of life. Mean time to tumor progression was 730 ± 54 days (Kaplan-Meier estimate). No RFA-associated complications were reported. Conclusion: RFA of primary and secondary spinal tumors, which were unresponsive to chemo- and radiotherapy and prone to progression, is a safe, resource-saving, and highly effective percutaneous technique in patients with nonresectable spinal tumors

Factors Limiting Complete Tumor Ablation by Radiofrequency Ablation

International Nuclear Information System (INIS)

Paulet, Erwan; Aube, Christophe; Pessaux, Patrick; Lebigot, Jerome; Lhermitte, Emilie; Oberti, Frederic; Ponthieux, Anne; Cales, Paul; Ridereau-Zins, Catherine; Pereira, Philippe L.

2008-01-01

The purpose of this study was to determine radiological or physical factors to predict the risk of residual mass or local recurrence of primary and secondary hepatic tumors treated by radiofrequency ablation (RFA). Eighty-two patients, with 146 lesions (80 hepatocellular carcinomas, 66 metastases), were treated by RFA. Morphological parameters of the lesions included size, location, number, ultrasound echogenicity, computed tomography density, and magnetic resonance signal intensity were obtained before and after treatment. Parameters of the generator were recorded during radiofrequency application. The recurrence-free group was statistically compared to the recurrence and residual mass groups on all these parameters. Twenty residual masses were detected. Twenty-nine lesions recurred after a mean follow-up of 18 months. Size was a predictive parameter. Patients' sex and age and the echogenicity and density of lesions were significantly different for the recurrence and residual mass groups compared to the recurrence-free group (p < 0.05). The presence of an enhanced ring on the magnetic resonance control was more frequent in the recurrence and residual mass groups. In the group of patients with residual lesions, analysis of physical parameters showed a significant increase (p < 0.05) in the time necessary for the temperature to rise. In conclusion, this study confirms risk factors of recurrence such as the size of the tumor and emphasizes other factors such as a posttreatment enhanced ring and an increase in the time necessary for the rise in temperature. These factors should be taken into consideration when performing RFA and during follow-up

Simulation of radiofrequency ablation in real human anatomy.

Science.gov (United States)

Zorbas, George; Samaras, Theodoros

2014-12-01

The objective of the current work was to simulate radiofrequency ablation treatment in computational models with realistic human anatomy, in order to investigate the effect of realistic geometry in the treatment outcome. The body sites considered in the study were liver, lung and kidney. One numerical model for each body site was obtained from Duke, member of the IT'IS Virtual Family. A spherical tumour was embedded in each model and a single electrode was inserted into the tumour. The same excitation voltage was used in all cases to underline the differences in the resulting temperature rise, due to different anatomy at each body site investigated. The same numerical calculations were performed for a two-compartment model of the tissue geometry, as well as with the use of an analytical approximation for a single tissue compartment. Radiofrequency ablation (RFA) therapy appears efficient for tumours in liver and lung, but less efficient in kidney. Moreover, the time evolution of temperature for a realistic geometry differs from that for a two-compartment model, but even more for an infinite homogenous tissue model. However, it appears that the most critical parameters of computational models for RFA treatment planning are tissue properties rather than tissue geometry. Computational simulations of realistic anatomy models show that the conventional technique of a single electrode inside the tumour volume requires a careful choice of both the excitation voltage and treatment time in order to achieve effective treatment, since the ablation zone differs considerably for various body sites.

The Bohm Criterion for Radiofrequency Discharges - a Numerical Verification Based on Poisson Equation

NARCIS (Netherlands)

Meijer, P. M.; W. J. Goedheer,

1993-01-01

Recently it was shown that, by using the analysis of electrostatic waves entering the plasma-sheath edge, the direct-current (dc) Bohm criterion also holds for discharges under radio-frequency (rf) conditions. In this paper, the influence of Bohm's criterion on the sheath characteristics for

Percutaneous radiofrequency ablation of spleen for the treatment of hypersplenism

International Nuclear Information System (INIS)

Wu Yuxuan; Zhang Yanfang; Zheng Xuefen; Zhang Yuanhua; Kong Jian; Shen Xinying; Dou Yongchong

2009-01-01

Objective: To summarize the clinical effect and experience of CT-guided radiofrequency ablation (RFA) of spleen by using cool-tip electrodes in the treatment of hypersplenism in patients with liver cirrhosis and portal hypertension. Methods: CT-guided RFA of spleen by using cool-tip electrodes was performed in 15 patients with hypersplenism associated with liver cirrhosis and portal hypertension. The routine blood count was studied both before and after the procedure. Enhanced CT or MR scanning was reexamined after the treatment to determine the ablated volume of the spleen. The results were statistically analyzed. Results: The ablated volume of the spleen accounted for (31.0 ± 4.6)% of the whole spleen. Before the treatment the platelet count was (62 ± 9.8) x 10 9 /L. One month after the treatment, the platelet count was increased to (96 ± 11) x 10 9 /L, which was significantly higher than that before the treatment (P<0.05). One patient developed portal thrombosis four months after RFA, and no other serious complications occurred. Conclusion: CT-guided radiofrequency ablation of spleen by using cool-tip electrodes is an effective and safe treatment for hypersplenism in patients with liver cirrhosis and portal hypertension. (authors)

Effects of 900 MHz radiofrequency radiation on skin hydroxyproline contents.

Science.gov (United States)

Çam, Semra Tepe; Seyhan, Nesrin; Kavaklı, Cengiz; Çelikbıçak, Ömür

2014-09-01

The present study aimed to investigate the possible effect of pulse-modulated radiofrequency radiation (RFR) on rat skin hydroxyproline content, since skin is the first target of external electromagnetic fields. Skin hydroxyproline content was measured using liquid chromatography mass spectrometer method. Two months old male wistar rats were exposed to a 900 MHz pulse-modulated RFR at an average whole body specific absorption rate (SAR) of 1.35 W/kg for 20 min/day for 3 weeks. The radiofrequency (RF) signals were pulse modulated by rectangular pulses with a repetition frequency of 217 Hz and a duty cycle of 1:8 (pulse width 0.576 ms). A skin biopsy was taken at the upper part of the abdominal costa after the exposure. The data indicated that whole body exposure to a pulse-modulated RF radiation that is similar to that emitted by the global system for mobile communications (GSM) mobile phones caused a statistically significant increase in the skin hydroxyproline level (p = 0.049, Mann-Whitney U test). Under our experimental conditions, at a SAR less than the International Commission on Non-Ionizing Radiation Protection safety limit recommendation, there was evidence that GSM signals could alter hydroxyproline concentration in the rat skin.

Profiling gene expression induced by protease-activated receptor 2 (PAR2 activation in human kidney cells.

Directory of Open Access Journals (Sweden)

Jacky Y Suen

Full Text Available Protease-Activated Receptor-2 (PAR2 has been implicated through genetic knockout mice with cytokine regulation and arthritis development. Many studies have associated PAR2 with inflammatory conditions (arthritis, airways inflammation, IBD and key events in tumor progression (angiogenesis, metastasis, but they have relied heavily on the use of single agonists to identify physiological roles for PAR2. However such probes are now known not to be highly selective for PAR2, and thus precisely what PAR2 does and what mechanisms of downstream regulation are truly affected remain obscure. Effects of PAR2 activation on gene expression in Human Embryonic Kidney cells (HEK293, a commonly studied cell line in PAR2 research, were investigated here by comparing 19,000 human genes for intersecting up- or down-regulation by both trypsin (an endogenous protease that activates PAR2 and a PAR2 activating hexapeptide (2f-LIGRLO-NH(2. Among 2,500 human genes regulated similarly by both agonists, there were clear associations between PAR2 activation and cellular metabolism (1,000 genes, the cell cycle, the MAPK pathway, HDAC and sirtuin enzymes, inflammatory cytokines, and anti-complement function. PAR-2 activation up-regulated four genes more than 5 fold (DUSP6, WWOX, AREG, SERPINB2 and down-regulated another six genes more than 3 fold (TXNIP, RARG, ITGB4, CTSD, MSC and TM4SF15. Both PAR2 and PAR1 activation resulted in up-regulated expression of several genes (CD44, FOSL1, TNFRSF12A, RAB3A, COPEB, CORO1C, THBS1, SDC4 known to be important in cancer. This is the first widespread profiling of specific activation of PAR2 and provides a valuable platform for better understanding key mechanistic roles of PAR2 in human physiology. Results clearly support the development of both antagonists and agonists of human PAR2 as potential disease modifying therapeutic agents.

par genes in Mycobacterium bovis and Mycobacterium smegmatis are arranged in an operon transcribed from "SigGC" promoters

Directory of Open Access Journals (Sweden)

Casart Yveth

2008-03-01

Full Text Available Abstract Background The ParA/Soj and ParB/Spo0J proteins, and the cis-acting parS site, participate actively in chromosome segregation and cell cycle progression. Genes homologous to parA and parB, and two putative parS copies, have been identified in the Mycobacterium bovis BCG and Mycobacterium smegmatis chromosomes. As in Mycobacterium tuberculosis, the parA and parB genes in these two non-pathogenic mycobacteria are located near the chromosomal origin of replication. The present work focused on the determination of the transcriptional organisation of the ~6 Kb orf60K-parB region of M. bovis BCG and M. smegmatis by primer extension, transcriptional fusions to the green fluorescence protein (GFP and quantitative RT-PCR. Results The parAB genes were arranged in an operon. However, we also found promoters upstream of each one of these genes. Seven putative promoter sequences were identified in the orf60K-parB region of M. bovis BCG, whilst four were identified in the homologous region of M. smegmatis, one upstream of each open reading frame (ORF. Real-time PCR assays showed that in M. smegmatis, mRNA-parA and mRNA-parB levels decreased between the exponential and stationary phases. In M. bovis BCG, mRNA-parA levels also decreased between the exponential and stationary phases. However, parB expression was higher than parA expression and remained almost unchanged along the growth curve. Conclusion The majority of the proposed promoter regions had features characteristic of Mycobacterium promoters previously denoted as Group D. The -10 hexamer of a strong E. coli σ70-like promoter, located upstream of gidB of M. bovis BCG, overlapped with a putative parS sequence, suggesting that the transcription from this promoter might be regulated by the binding of ParB to parS.

Radiofrequency encoded angular-resolved light scattering

DEFF Research Database (Denmark)

Buckley, Brandon W.; Akbari, Najva; Diebold, Eric D.

2015-01-01

The sensitive, specific, and label-free classification of microscopic cells and organisms is one of the outstanding problems in biology. Today, instruments such as the flow cytometer use a combination of light scatter measurements at two distinct angles to infer the size and internal complexity...... of cells at rates of more than 10,000 per second. However, by examining the entire angular light scattering spectrum it is possible to classify cells with higher resolution and specificity. Current approaches to performing these angular spectrum measurements all have significant throughput limitations...... Encoded Angular-resolved Light Scattering (REALS), this technique multiplexes angular light scattering in the radiofrequency domain, such that a single photodetector captures the entire scattering spectrum from a particle over approximately 100 discrete incident angles on a single shot basis. As a proof...

Radiofrequency Electromagnetic Field Map of Timisoara

Science.gov (United States)

Stefu, N.; Solyom, I.; Arama, A.

2015-12-01

There are many electromagnetic field (EMF) sources nowadays acting simultaneously, especially in urban areas, making the theoretical estimation of electromagnetic power at ground level very difficult. This paper reports on EMF maps built with measurements collected in Timisoara, at various radiofrequencies. A grid of 15×15 squares was built (approximate resolution 400m x 400m) and measurements of the average and maximum values of the electric field E, magnetic field H and total power density S at 0.9, 1.8 and 2.4 GHz were collected in every node of the grid. Positions of the nodes in terms of latitude and longitude were also collected. Maps were built presenting the spatial distribution of the measured quantities over Timisoara. Potential influences of EMF on public health are discussed.

Cardiac magnetic resonance radiofrequency tissue tagging for diagnosis of constrictive pericarditis: A proof of concept study.

Science.gov (United States)

Power, John A; Thompson, Diane V; Rayarao, Geetha; Doyle, Mark; Biederman, Robert W W

2016-05-01

Invasive cardiac catheterization is the venerable "gold standard" for diagnosing constrictive pericarditis. However, its sensitivity and specificity vary dramatically from center to center. Given the ability to unequivocally define segments of the pericardium with the heart via radiofrequency tissue tagging, we hypothesize that cardiac magnetic resonance has the capability to be the new gold standard. All patients who were referred for cardiac magnetic resonance evaluation of constrictive pericarditis underwent cardiac magnetic resonance radiofrequency tissue tagging to define visceral-parietal pericardial adherence to determine constriction. This was then compared with intraoperative surgical findings. Likewise, all preoperative cardiac catheterization testing was reviewed in a blinded manner. A total of 120 patients were referred for clinical suspicion of constrictive pericarditis. Thirty-nine patients were defined as constrictive pericarditis positive solely via radiofrequency tissue-tagging cardiac magnetic resonance, of whom 21 were positive, 4 were negative, and 1 was equivocal for constrictive pericarditis, as defined by cardiac catheterization. Of these patients, 16 underwent pericardiectomy and were surgically confirmed. There was 100% agreement between cardiac magnetic resonance-defined constrictive pericarditis positivity and postsurgical findings. No patients were misclassified by cardiac magnetic resonance. In regard to the remaining constrictive pericarditis-positive patients defined by cardiac magnetic resonance, 10 were treated medically, declined, were ineligible for surgery, or were lost to follow-up. Long-term follow-up of those who were constrictive pericarditis negative by cardiac magnetic resonance showed no early or late crossover to the surgery arm. Cardiac magnetic resonance via radiofrequency tissue tagging offers a unique, efficient, and effective manner of defining clinically and surgically relevant constrictive pericarditis

Par-4-mediated recruitment of Amida to the actin cytoskeleton leads to the induction of apoptosis

International Nuclear Information System (INIS)

Boosen, Meike; Vetterkind, Susanne; Koplin, Ansgar; Illenberger, Susanne; Preuss, Ute

2005-01-01

Par-4 (prostate apoptosis response-4) sensitizes cells to apoptotic stimuli, but the exact mechanisms are still poorly understood. Using Par-4 as bait in a yeast two-hybrid screen, we identified Amida as a novel interaction partner, a ubiquitously expressed protein which has been suggested to be involved in apoptotic processes. Complex formation of Par-4 and Amida occurs in vitro and in vivo and is mediated via the C-termini of both proteins, involving the leucine zipper of Par-4. Amida resides mainly in the nucleus but displays nucleo-cytoplasmic shuttling in heterokaryons. Upon coexpression with Par-4 in REF52.2 cells, Amida translocates to the cytoplasm and is recruited to actin filaments by Par-4, resulting in enhanced induction of apoptosis. The synergistic effect of Amida/Par-4 complexes on the induction of apoptosis is abrogated when either Amida/Par-4 complex formation or association of these complexes with the actin cytoskeleton is impaired, indicating that the Par-4-mediated relocation of Amida to the actin cytoskeleton is crucial for the pro-apoptotic function of Par-4/Amida complexes in REF52.2 cells. The latter results in enhanced phosphorylation of the regulatory light chain of myosin II (MLC) as has previously been shown for Par-4-mediated recruitment of DAP-like kinase (Dlk), suggesting that the recruitment of nuclear proteins involved in the regulation of apoptotic processes to the actin filament system by Par-4 represents a potent mechanism how Par-4 can trigger apoptosis

Factors related to postoperative pain among patients who underwent radiofrequency ablation of hepatocellular carcinoma

International Nuclear Information System (INIS)

Hsieh, Y.-C.; Yap, Y.-S.; Hung, C.-H.; Chen, C.-H.; Lu, S.-N.; Wang, J.-H.

2013-01-01

Aim: To evaluate the incidence and associated factors of postoperative intense pain and haemodynamic changes during radiofrequency ablation of hepatocellular carcinoma. Materials and methods: A total of 123 consecutive hepatocellular carcinoma patients who underwent radiofrequency ablation were prospectively recruited. Patient factors, tumour characteristics, procedural factors, intraoperative haemodynamic changes, complications, postoperative events, laboratory values before and after ablation, and postoperative pain were evaluated. Postoperative pain was scored using a visual analogue scale after the procedure. Results: The mean age of the patients was 65.6 ± 9.6 years. In multiple logistic regression analysis, patients who underwent general anaesthesia [odds ratio (95% CI): 2.68 (1.23–5.81); p = 0.013] and had more postoperative nausea and vomiting episodes [3.10 (1.11–8.63); p = 0.036] were associated with intense pain. These findings remain robust after propensity score matching. For mean difference values between before and after RFA, higher in change in aspartate transaminase (p = 0.026), alanine transaminase (p = 0.016) and white blood cell count (p = 0.015), and lower in change in haemoglobin (p = 0.009) were also correlated with intense pain. There was no significant difference in haemodynamic changes between the general anaesthesia and local anaesthesia group during ablation. Conclusion: General anaesthesia, postoperative nausea and vomiting, and laboratory factors were associated with postoperative intense pain in patients who underwent radiofrequency ablation. Counselling and modification of analgesics should be considered in patients with related factors for intense pain

Risk assessment and management of radiofrequency radiation exposure

Energy Technology Data Exchange (ETDEWEB)

Dabala, Dana [Railways Medical Clinic Cluj-Napoca, Occupational Medicine Department, 16-20 Bilascu Gheorghe St., 400015 Cluj-Napoca (Romania); Surducan, Emanoil; Surducan, Vasile; Neamtu, Camelia [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath St., 400293 Cluj-Napoca (Romania)

2013-11-13

Radiofrequency radiation (RFR) industry managers, occupational physicians, security department, and other practitioners must be advised on the basic of biophysics and the health effects of RF electromagnetic fields so as to guide the management of exposure. Information on biophysics of RFR and biological/heath effects is derived from standard texts, literature and clinical experiences. Emergency treatment and ongoing care is outlined, with clinical approach integrating the circumstances of exposure and the patient's symptoms. Experimental risk assessment model in RFR chronic exposure is proposed. Planning for assessment and monitoring exposure, ongoing care, safety measures and work protection are outlining the proper management.

Risk assessment and management of radiofrequency radiation exposure

International Nuclear Information System (INIS)

Dabala, Dana; Surducan, Emanoil; Surducan, Vasile; Neamtu, Camelia

2013-01-01

Radiofrequency radiation (RFR) industry managers, occupational physicians, security department, and other practitioners must be advised on the basic of biophysics and the health effects of RF electromagnetic fields so as to guide the management of exposure. Information on biophysics of RFR and biological/heath effects is derived from standard texts, literature and clinical experiences. Emergency treatment and ongoing care is outlined, with clinical approach integrating the circumstances of exposure and the patient's symptoms. Experimental risk assessment model in RFR chronic exposure is proposed. Planning for assessment and monitoring exposure, ongoing care, safety measures and work protection are outlining the proper management

Prognostic value of suPAR and hs-CRP on cardiovascular disease

DEFF Research Database (Denmark)

Diederichsen, Marie Zöga; Diederichsen, Søren Zöga; Mickley, Hans

2018-01-01

Background and aims: Studies have shown that soluble urokinase Plasminogen Activator Receptor (suPAR) and CRP (both inflammatory markers) and coronary artery calcification (CAC) are independent risk predictors for cardiovascular (CV) disease. The aim of this study is to assess whether suPAR and CRP...... have an increased predictive prognostic value beyond the traditional CV risk factors and the CAC score. Methods: A population sample of 1179 subjects, free of CV disease was included. The subjects underwent traditional CV risk evaluation, CAC assessment and blood sampling for suPAR and CRP. CV events...

mTORC2 activation is regulated by the urokinase receptor (uPAR) in bladder cancer.

Science.gov (United States)

Hau, Andrew M; Leivo, Mariah Z; Gilder, Andrew S; Hu, Jing-Jing; Gonias, Steven L; Hansel, Donna E

2017-01-01

Mammalian target of rapamycin complex 2 (mTORC2) has been identified as a major regulator of bladder cancer cell migration and invasion. Upstream pathways that mediate mTORC2 activation remain poorly defined. Urokinase-type plasminogen activator receptor (uPAR) is a GPI-anchored membrane protein and known activator of cell-signaling. We identified increased uPAR expression in 94% of invasive human bladder cancers and in 54-71% of non-invasive bladder cancers, depending on grade. Normal urothelium was uPAR-immunonegative. Analysis of publicly available datasets identified uPAR gene amplification or mRNA upregulation in a subset of bladder cancer patients with reduced overall survival. Using biochemical approaches, we showed that uPAR activates mTORC2 in bladder cancer cells. Highly invasive bladder cancer cell lines, including T24, J82 and UM-UC-3 cells, showed increased uPAR mRNA expression and protein levels compared with the less aggressive cell lines, UROtsa and RT4. uPAR gene-silencing significantly reduced phosphorylation of Serine-473 in Akt, an mTORC2 target. uPAR gene-silencing also reduced bladder cancer cell migration and Matrigel invasion. S473 phosphorylation was observed by immunohistochemistry in human bladder cancers only when the tumors expressed high levels of uPAR. S473 phosphorylation was not controlled by uPAR in bladder cancer cell lines that are PTEN-negative; however, this result probably did not reflect altered mTORC2 regulation. Instead, PTEN deficiency de-repressed alternative kinases that phosphorylate S473. Our results suggest that uPAR and mTORC2 are components of a single cell-signaling pathway. Targeting uPAR or mTORC2 may be beneficial in patients with bladder cancer. Copyright © 2016. Published by Elsevier Inc.

Anthropogenic radiofrequency electromagnetic fields as an emerging threat to wildlife orientation

International Nuclear Information System (INIS)

Balmori, Alfonso

2015-01-01

The rate of scientific activity regarding the effects of anthropogenic electromagnetic radiation in the radiofrequency (RF) range on animals and plants has been small despite the fact that this topic is relevant to the fields of experimental biology, ecology and conservation due to its remarkable expansion over the past 20 years. Current evidence indicates that exposure at levels that are found in the environment (in urban areas and near base stations) may particularly alter the receptor organs to orient in the magnetic field of the earth. These results could have important implications for migratory birds and insects, especially in urban areas, but could also apply to birds and insects in natural and protected areas where there are powerful base station emitters of radiofrequencies. Therefore, more research on the effects of electromagnetic radiation in nature is needed to investigate this emerging threat. - Highlights: • The growth of wireless telecommunication technologies causes increased electrosmog. • Radio frequency fields in the MHz range disrupt insect and bird orientation. • Radio frequency noise interferes with the primary process of magnetoreception. • Existing guidelines do not adequately protect wildlife. • Further research in this area is urgent

Anthropogenic radiofrequency electromagnetic fields as an emerging threat to wildlife orientation

Energy Technology Data Exchange (ETDEWEB)

Balmori, Alfonso, E-mail: balmaral@jcyl.es

2015-06-15

The rate of scientific activity regarding the effects of anthropogenic electromagnetic radiation in the radiofrequency (RF) range on animals and plants has been small despite the fact that this topic is relevant to the fields of experimental biology, ecology and conservation due to its remarkable expansion over the past 20 years. Current evidence indicates that exposure at levels that are found in the environment (in urban areas and near base stations) may particularly alter the receptor organs to orient in the magnetic field of the earth. These results could have important implications for migratory birds and insects, especially in urban areas, but could also apply to birds and insects in natural and protected areas where there are powerful base station emitters of radiofrequencies. Therefore, more research on the effects of electromagnetic radiation in nature is needed to investigate this emerging threat. - Highlights: • The growth of wireless telecommunication technologies causes increased electrosmog. • Radio frequency fields in the MHz range disrupt insect and bird orientation. • Radio frequency noise interferes with the primary process of magnetoreception. • Existing guidelines do not adequately protect wildlife. • Further research in this area is urgent.

Clinical and Histologic Effects of Fractional Microneedling Radiofrequency Treatment on Rosacea.

Science.gov (United States)

Park, Seon Yong; Kwon, Hyuck Hoon; Yoon, Ji Young; Min, Seonguk; Suh, Dae Hun

2016-12-01

Fractional microneedling radiofrequency (FMR) is an emerging treatment modality, but its effect on rosacea has not been studied yet. To investigate the potential impact of FMR treatment on clinical improvement and histologic changes in rosacea patients. A 12-week, prospective, randomized, split-face clinical trial was conducted. Two sessions of FMR were performed on one side of the cheeks with 4-week interval and the other side remained untreated. Erythema index from DermaSpectrometer and a* value from Spectrophotometer CM-2002 were measured at each visit for the objective measurement of erythema. Histologic analysis of skin samples was also carried out. Clinical evaluation and photometric measurement revealed the reduction of redness in the treated side compared with untreated side and baseline. Erythema index decreased 13.6% and a* value decreased 6.8% at Week 12 compared with baseline. Reduced expression of markers related to inflammation, innate immunity, and angiogenesis was observed in immunohistochemical staining of tissue obtained after FMR treatment. Fractional microneedling radiofrequency treatment showed modest clinical and histologic improvement of rosacea, and it might be used as an alternative or in combination with other treatment methods.

Ultrasound-guided radiofrequency thermal ablation of normal kidney in a rabbit model: correlation with CT and histopathology

Energy Technology Data Exchange (ETDEWEB)

Kim, Sang Won; Lee, Jeong Min; Kin, Chong Soo; Lee, Sang Hun [College of Medicine, Chonbuk National Univ., Chonju (Korea, Republic of)

2002-01-01

To assess the feasibility and safety of using a cooled-tip electrode to perform percutaneous radiofrequency ablation of kidney tissue in rabbits, and to evaluate the ability of CT to reveal the appearance and extent of tissue necrosis during follow-up after ablation. Using ultrasound guidance, a 17-G cooled-tip electrode was inserted into the right lower portion of the kidney in 26 New Zealand White rabbits. Radiofrequency was applied for 2 mins, and biphasic helical CT scanning was used to assess tissue destruction and the presence or absence of complications immediately after the procedure and at 24 hrs, 2 and 3 days, and 1,2,3,4,5,6 and 7 weeks. The study had three phases: acute (immediately killed : N=10); subacute (killed at 24 hrs (n=3), 2 days (n=3), 3 days (n=1) : N=7); chronic (killed at 1 week (n=4), 2 weeks (n=2), 4 weeks (n=1), 7 weeks (n=1): N=8). After the animals were killed, their kidneys were histopathologically examined and the radiologic and pathologic findings of lesion size and configuration were correlated. In each instance, ultrasound-guided radiofrequency ablations of the lower pole of the kidney were technically successful. Contrast-enhanced biphasic helical CT revealed regions of hypoattenuation devoid of parenchymal enhancement, and these correlated closely with true pathologic lesion size (r=0.884; p>0.05). In subacute and chronic models, CT scanning revealed gradual spontaneous resorption of the ablated lesion and the presence of perilesional calcification. Histopathologically, in the acute phase the ablated lesion showed coagulative necrosis and infiltration of inflammatory cells, and in the chronic phase there was clear cut necrosis of glomeruli, tubules and renal interstitium, with diminishing inflammatory response and peripheral fibrotic tissue formation. Ultrasound-guided renal radiofrequency ablation is technically feasible and safe. In addition, the avascular lesion measured at contrast-enhanced helical CT closely correlated with

Ultrasound-guided radiofrequency thermal ablation of normal kidney in a rabbit model: correlation with CT and histopathology

International Nuclear Information System (INIS)

Kim, Sang Won; Lee, Jeong Min; Kin, Chong Soo; Lee, Sang Hun

2002-01-01

To assess the feasibility and safety of using a cooled-tip electrode to perform percutaneous radiofrequency ablation of kidney tissue in rabbits, and to evaluate the ability of CT to reveal the appearance and extent of tissue necrosis during follow-up after ablation. Using ultrasound guidance, a 17-G cooled-tip electrode was inserted into the right lower portion of the kidney in 26 New Zealand White rabbits. Radiofrequency was applied for 2 mins, and biphasic helical CT scanning was used to assess tissue destruction and the presence or absence of complications immediately after the procedure and at 24 hrs, 2 and 3 days, and 1,2,3,4,5,6 and 7 weeks. The study had three phases: acute (immediately killed : N=10); subacute (killed at 24 hrs (n=3), 2 days (n=3), 3 days (n=1) : N=7); chronic (killed at 1 week (n=4), 2 weeks (n=2), 4 weeks (n=1), 7 weeks (n=1): N=8). After the animals were killed, their kidneys were histopathologically examined and the radiologic and pathologic findings of lesion size and configuration were correlated. In each instance, ultrasound-guided radiofrequency ablations of the lower pole of the kidney were technically successful. Contrast-enhanced biphasic helical CT revealed regions of hypoattenuation devoid of parenchymal enhancement, and these correlated closely with true pathologic lesion size (r=0.884; p>0.05). In subacute and chronic models, CT scanning revealed gradual spontaneous resorption of the ablated lesion and the presence of perilesional calcification. Histopathologically, in the acute phase the ablated lesion showed coagulative necrosis and infiltration of inflammatory cells, and in the chronic phase there was clear cut necrosis of glomeruli, tubules and renal interstitium, with diminishing inflammatory response and peripheral fibrotic tissue formation. Ultrasound-guided renal radiofrequency ablation is technically feasible and safe. In addition, the avascular lesion measured at contrast-enhanced helical CT closely correlated with

Measuring Radiofrequency and Microwave Radiation from Varying Signal Strengths

Science.gov (United States)

Davis, Bette; Gaul, W. C.

2007-01-01

This viewgraph presentation discusses the process of measuring radiofrequency and microwave radiation from various signal strengths. The topics include: 1) Limits and Guidelines; 2) Typical Variable Standard (IEEE) Frequency Dependent; 3) FCC Standard 47 CFR 1.1310; 4) Compliance Follows Unity Rule; 5) Multiple Sources Contribute; 6) Types of RF Signals; 7) Interfering Radiations; 8) Different Frequencies Different Powers; 9) Power Summing - Peak Power; 10) Contribution from Various Single Sources; 11) Total Power from Multiple Sources; 12) Are You Out of Compliance?; and 13) In Compliance.

Long-term Nasal and Peri-oral Tightening by a Single Fractional Noninsulated Microneedle Radiofrequency Treatment.

Science.gov (United States)

Tanaka, Yohei

2017-02-01

Background: The skin tightening effects induced by non-insulated microneedle radiofrequency have proved long-lasting. Our previous three-dimensional volumetric assessment showed significant facial tightening for up to six months. However, nasal and peri-oral tightening effects lasted longer. The objective of this study was to investigate the distribution of the long-term volumetric reduction in facial area induced by a single fractional non-insulated microneedle radiofrequency treatment. Methods: Fifteen Asian patients underwent full facial skin tightening using a sharply tapered non-insulated microneedle radiofrequency applicator with a novel fractionated pulse mode. Three-dimensional volumetric assessments were performed at six and 12 months post-treatment. Patients rated their satisfaction using a 5-point scale at each follow up. Results: Objective assessments with superimposed three-dimensional color images showed significant volumetric reduction in the nasal and peri-oral areas at 12 months post-treatment in all patients. Median volumetric reductions at six and 12 months post-treatment were 13.1 and 12.3ml, respectively. All of the patients were satisfied with their results 12 months post-treatment. Side effects were not observed. Conclusions: This single fractional NIMNRF treatment provided long-lasting nasal and peri-oral tightening as shown via 3D volumetric assessment. Moreover, NIMNRF produced minimal complications, downtime, and few side effects. This approach provides safe and effective treatment of skin tightening.

Radiofrequency ablation of chondroblastoma: procedure technique, clinical and MR imaging follow up of four cases

Energy Technology Data Exchange (ETDEWEB)

Christie-Large, M.; Evans, N.; Davies, A.M.; James, S.L.J. [Royal Orthopaedic Hospital Foundation Trust, Department of Radiology, Birmingham (United Kingdom)

2008-11-15

The aim of this study is to describe the procedure technique, clinical and imaging outcomes of patients treated with radiofrequency ablation for chondroblastoma. Four patients (female/male, 3:1; mean age, 13 years; age range; 9-16 years) underwent the procedure. All had pre-operative magnetic resonance imaging (MRI) and symptomatic, biopsy-proven chondroblastomas (two proximal femur, two proximal tibia). The lesion size ranged from 1.5 to 2.5 cm in maximal dimension (mean size, 1.8 cm). Bone access was gained with a Bonopty biopsy needle system (mean number of radiofrequency needle placements, 5; mean ablation time, 31 min). Clinical and MRI follow-up was available in all cases (mean, 12.25 months; range, 5-18 months). All patients reported resolution of symptoms at 2-6 weeks post ablation. At their most recent clinical follow-up, three patients remained completely asymptomatic with full return to normal activities and one patient had minor local discomfort (different pain pattern) that was not limiting activity. All four patients' follow-up MRI studies demonstrated resolution of the oedema pattern around the lesion and temporal evolution of the internal signal characteristics with fatty replacement. Radiofrequency ablation for chondroblastoma provides an alternative to surgical curettage, and we have demonstrated both a clinical improvement in symptoms and the follow-up MRI appearances. (orig.)

Radio-frequency properties of stacked long Josephson junctions with nonuniform bias current distribution

DEFF Research Database (Denmark)

Filatrella, G; Pedersen, Niels Falsig

1999-01-01

We have numerically investigated the behavior of stacks of long Josephson junctions considering a nonuniform bias profile. In the presence of a microwave field the nonuniform bias, which favors the formation of fluxons, can give rise to a change of the sequence of radio-frequency induced steps...

Treatment response assessment of radiofrequency ablation for hepatocellular carcinoma: Usefulness of virtual CT sonography with magnetic navigation

International Nuclear Information System (INIS)

Minami, Yasunori; Kitai, Satoshi; Kudo, Masatoshi

2012-01-01

Purpose: Virtual CT sonography using magnetic navigation provides cross sectional images of CT volume data corresponding to the angle of the transducer in the magnetic field in real-time. The purpose of this study was to clarify the value of this virtual CT sonography for treatment response of radiofrequency ablation for hepatocellular carcinoma. Patients and methods: Sixty-one patients with 88 HCCs measuring 0.5–1.3 cm (mean ± SD, 1.0 ± 0.3 cm) were treated by radiofrequency ablation. For early treatment response, dynamic CT was performed 1–5 days (median, 2 days). We compared early treatment response between axial CT images and multi-angle CT images using virtual CT sonography. Results: Residual tumor stains on axial CT images and multi-angle CT images were detected in 11.4% (10/88) and 13.6% (12/88) after the first session of RFA, respectively (P = 0.65). Two patients were diagnosed as showing hyperemia enhancement after the initial radiofrequency ablation on axial CT images and showed local tumor progression shortly because of unnoticed residual tumors. Only virtual CT sonography with magnetic navigation retrospectively showed the residual tumor as circular enhancement. In safety margin analysis, 10 patients were excluded because of residual tumors. The safety margin more than 5 mm by virtual CT sonographic images and transverse CT images were determined in 71.8% (56/78) and 82.1% (64/78), respectively (P = 0.13). The safety margin should be overestimated on axial CT images in 8 nodules. Conclusion: Virtual CT sonography with magnetic navigation was useful in evaluating the treatment response of radiofrequency ablation therapy for hepatocellular carcinoma.

[Radiofrequency ablation of hepatocellular carcinoma].

Science.gov (United States)

Widmann, Gerlig; Schullian, Peter; Bale, Reto

2013-03-01

Percutaneous radiofrequency ablation (RFA) is well established in the treatment of hepatocellular carcinoma (HCC). Due to its curative potential, it is the method of choice for non resectable BCLC (Barcelona Liver Clinic) 0 and A. RFA challenges surgical resection for small HCC and is the method of choice in bridging for transplantation and recurrence after resection or transplantation. The technical feasibility of RFA depends on the size and location of the HCC and the availability of ablation techniques (one needle techniques, multi-needle techniques). More recently, stereotactic multi-needle techniques with 3D trajectory planning and guided needle placement substantially improve the spectrum of treatable lesions including large volume tumors. Treatment success depends on the realization of ablations with large intentional margins of tumor free tissue (A0 ablation in analogy to R0 resection), which has to be documented by fusion of post- with pre-ablation images, and confirmed during follow-up imaging.

Réduction du risque d'infection par le VIH au Botswana - essais ...

International Development Research Centre (IDRC) Digital Library (Canada)

Au Botswana, ce sont les jeunes femmes qui sont le plus touchées par les nouvelles infections par le VIH. Le présent projet a pour but de réduire le nombre de nouveaux cas d'infection par le VIH, en particulier chez les femmes de 15 à 29 ans. Bien que l'on recense des cas de VIH/sida dans la plupart des régions du ...

Evaluation of the clinical efficacy of fractional radiofrequency microneedle treatment in acne scars and large facial pores.

Science.gov (United States)

Cho, Soo Ick; Chung, Bo Young; Choi, Min Gyu; Baek, Ji Hwoon; Cho, Hee Jin; Park, Chun Wook; Lee, Cheol Heon; Kim, Hye One

2012-07-01

Fractional technology overcomes the problems of ablative lasers, such as inaccurate depth control and damage to the epidermis. Minimally invasive fractional radiofrequency microneedle devices allow for more-selective heating of the dermis. To evaluate the clinical efficacy of fractional radiofrequency microneedle (ERM) treatment in acne scars and large facial pores. Thirty patients with acne scars and large facial pores were enrolled. Bipolar radiofrequency energy was delivered to the skin through the electrodes of the FRM device. Skin lesions were evaluated according to grade of acne scars, Investigator Global Assessment of large pores, skin surface roughness, transepidermal water loss (TEWL), dermal density, microscopic and composite image, sebum measurement, and questionnaires regarding patient satisfaction. The grade of acne scars and Investigator Global Assessment of large pores improved in more than 70% of all patients. Skin surface roughness, dermal density, and microscopic and composite images also improved, whereas TEWL and sebum measurement did not change. Clinical improvement from FRM treatment appeared to be related to dermal matrix regeneration. FRM treatment may be effective in improving acne scars and facial pores. © 2012 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

Radiofrequency thermocoagulation for the treatment of lumbar intervertebral disc protrusion: a clinical observation of 30 cases

International Nuclear Information System (INIS)

Gong Weidong; Li Yazhou; Cao Wei; Yang Wei; Zhang Peng; Wang Zhimin; Wu Zhiqun

2010-01-01

Objective: To observe the clinical effects and safety of radiofrequency thermocoagulation in treating the lumbar intervertebral disc protrusion. Methods: Thirty patients with lumbar intervertebral disc protrusion, whose diagnoses were confirmed by clinical manifestations and CT findings, were involved in this study. The needle was punctured to the target point of the diseased intervertebral space under C-arm fluoroscopic guidance. After the testing of sensory nerve, motor nerve and temperature was made, the target needles were heated until the nerve radiofrequency temperature meter reached the point of 92 degree C. This point of temperature was held for 100 seconds and the procedure was repeated for four cycles. Results: Six months after the treatment, all patients showed an obvious improvement in VAS, which decreased from 7.83 ± 0.33 before operation to 2.37 ± 0.48 after treatment (P < 0.05). According to the modified Macnab therapeutic evaluation criteria, excellent result was seen in 9, good result in 12, fair result in 5 and poor result in 4 cases, with a total effective rate of 86.7%. No serious complications occurred in all patients. Conclusion: Radiofrequency thermocoagulation is an effective and safe method for the treatment of lumbar intervertebral disc protrusion. (authors)

Heating of polymer substrate by discharge plasma in radiofrequency magnetron sputtering deposition

International Nuclear Information System (INIS)

Sirghi, Lucel; Popa, Gheorghe; Hatanaka, Yoshinori

2006-01-01

The substrate used for the thin film deposition in a radiofrequency magnetron sputtering deposition system is heated by the deposition plasma. This may change drastically the surface properties of the polymer substrates. Deposition of titanium dioxide thin films on polymethyl methacrylate and polycarbonate substrates resulted in buckling of the substrate surfaces. This effect was evaluated by analysis of atomic force microscopy topography images of the deposited films. The amount of energy received by the substrate surface during the film deposition was determined by a thermal probe. Then, the results of the thermal probe measurements were used to compute the surface temperature of the polymer substrate. The computation revealed that the substrate surface temperature depends on the substrate thickness, discharge power and substrate holder temperature. For the case of the TiO 2 film depositions in the radiofrequency magnetron plasma, the computation indicated substrate surface temperature values under the polymer melting temperature. Therefore, the buckling of polymer substrate surface in the deposition plasma may not be regarded as a temperature driven surface instability, but more as an effect of argon ion bombardment

An image-guided system for optimized volumetric treatment planning and execution for radiofrequency ablation of liver tumors

Energy Technology Data Exchange (ETDEWEB)

Banovac, F.; Popa, T.; Cheng, P.; Cleary, K. [Computer Aided Interventions and Medical Robotics (CAIMR), Imaging Science and Information Systems (ISIS) Center, Georgetown Univ. Medical Center, Washington, DC (United States); Abeledo, H.; Campos-Nanez, E. [Dept. of Engineering Management and System Engineering, George Washington Univ., Washington, DC (United States); Wood, B.J. [Diagnostic Radiology Dept., NIH Clinical Center, Bethesda, MD (United States)

2007-06-15

Radiofrequency ablation of liver tumors is becoming an increasingly popular option for the treatment of cancer. However, the procedure has several technical challenges, mostly associated with precision targeting of the tumor and ensuring complete ablation coverage. In this paper we describe an image-guided system that we are developing for improved visualization and probe placement during these procedures. The system will include a pre-procedure optimization module and an intra-procedure guidance component. The system concept is explained and some preliminary results are given. While this system is designed for radiofrequency ablation of liver tumors, the methods are applicable to other organs and treatment methods. (orig.)

Assessment of outdoor radiofrequency electromagnetic field exposure through hotspot localization using kriging-based sequential sampling.

Science.gov (United States)

Aerts, Sam; Deschrijver, Dirk; Verloock, Leen; Dhaene, Tom; Martens, Luc; Joseph, Wout

2013-10-01

In this study, a novel methodology is proposed to create heat maps that accurately pinpoint the outdoor locations with elevated exposure to radiofrequency electromagnetic fields (RF-EMF) in an extensive urban region (or, hotspots), and that would allow local authorities and epidemiologists to efficiently assess the locations and spectral composition of these hotspots, while at the same time developing a global picture of the exposure in the area. Moreover, no prior knowledge about the presence of radiofrequency radiation sources (e.g., base station parameters) is required. After building a surrogate model from the available data using kriging, the proposed method makes use of an iterative sampling strategy that selects new measurement locations at spots which are deemed to contain the most valuable information-inside hotspots or in search of them-based on the prediction uncertainty of the model. The method was tested and validated in an urban subarea of Ghent, Belgium with a size of approximately 1 km2. In total, 600 input and 50 validation measurements were performed using a broadband probe. Five hotspots were discovered and assessed, with maximum total electric-field strengths ranging from 1.3 to 3.1 V/m, satisfying the reference levels issued by the International Commission on Non-Ionizing Radiation Protection for exposure of the general public to RF-EMF. Spectrum analyzer measurements in these hotspots revealed five radiofrequency signals with a relevant contribution to the exposure. The radiofrequency radiation emitted by 900 MHz Global System for Mobile Communications (GSM) base stations was always dominant, with contributions ranging from 45% to 100%. Finally, validation of the subsequent surrogate models shows high prediction accuracy, with the final model featuring an average relative error of less than 2dB (factor 1.26 in electric-field strength), a correlation coefficient of 0.7, and a specificity of 0.96. Copyright © 2013 Elsevier Inc. All rights

Effect of Radiofrequency Denervation on Pain Intensity Among Patients With Chronic Low Back Pain: The Mint Randomized Clinical Trials.

Science.gov (United States)

Juch, Johan N S; Maas, Esther T; Ostelo, Raymond W J G; Groeneweg, J George; Kallewaard, Jan-Willem; Koes, Bart W; Verhagen, Arianne P; van Dongen, Johanna M; Huygen, Frank J P M; van Tulder, Maurits W

2017-07-04

Radiofrequency denervation is a commonly used treatment for chronic low back pain, but high-quality evidence for its effectiveness is lacking. To evaluate the effectiveness of radiofrequency denervation added to a standardized exercise program for patients with chronic low back pain. Three pragmatic multicenter, nonblinded randomized clinical trials on the effectiveness of minimal interventional treatments for participants with chronic low back pain (Mint study) were conducted in 16 multidisciplinary pain clinics in the Netherlands. Eligible participants were included between January 1, 2013, and October 24, 2014, and had chronic low back pain, a positive diagnostic block at the facet joints (facet joint trial, 251 participants), sacroiliac joints (sacroiliac joint trial, 228 participants), or a combination of facet joints, sacroiliac joints, or intervertebral disks (combination trial, 202 participants) and were unresponsive to conservative care. All participants received a 3-month standardized exercise program and psychological support if needed. Participants in the intervention group received radiofrequency denervation as well. This is usually a 1-time procedure, but the maximum number of treatments in the trial was 3. The primary outcome was pain intensity (numeric rating scale, 0-10; whereby 0 indicated no pain and 10 indicated worst pain imaginable) measured 3 months after the intervention. The prespecified minimal clinically important difference was defined as 2 points or more. Final follow-up was at 12 months, ending October 2015. Among 681 participants who were randomized (mean age, 52.2 years; 421 women [61.8%], mean baseline pain intensity, 7.1), 599 (88%) completed the 3-month follow-up, and 521 (77%) completed the 12-month follow-up. The mean difference in pain intensity between the radiofrequency denervation and control groups at 3 months was -0.18 (95% CI, -0.76 to 0.40) in the facet joint trial; -0.71 (95% CI, -1.35 to -0.06) in the sacroiliac joint

A mechanism for ParB-dependent waves of ParA, a protein related to DNA segregation during cell division in prokaryotes

DEFF Research Database (Denmark)

Hunding, Axel; Gerdes, Kenn; Charbon, Gitte Ebersbach

2003-01-01

in an autocatalytic process. We discuss this mechanism in relation to recent models for MinDE oscillations in E.coli and to microtubule degradation in mitosis. The study points to an ancestral role for the presented pattern types in generating bipolarity in prokaryotes and eukaryotes.......Prokaryotic plasmids encode partitioning (par) loci involved in segregation of DNA to daughter cells at cell division. A functional fusion protein consisting of Walker-type ParA ATPase and green fluorescent protein (Gfp) oscillates back and forth within nucleoid regions with a wave period of about...

Numerical study of the influence of water evaporation on radiofrequency ablation.

Science.gov (United States)

Zhu, Qing; Shen, Yuanyuan; Zhang, Aili; Xu, Lisa X

2013-12-10

Radiofrequency ablation is a promising minimal invasive treatment for tumor. However, water loss due to evaporation has been a major issue blocking further RF energy transmission and correspondently eliminating the therapeutic outcome of the treatment. A 2D symmetric cylindrical mathematical model coupling the transport of the electrical current, heat, and the evaporation process in the tissue, has been developed to simulate the treatment process and investigate the influence of the excessive evaporation of the water on the treatment. Our results show that the largest specific absorption rate (QSAR) occurs at the edge of the circular surface of the electrode. When excessive evaporation takes place, the water dehydration rate in this region is the highest, and after a certain time, the dehydrated tissue blocks the electrical energy transmission in the radial direction. It is found that there is an interval as long as 65 s between the beginning of the evaporation and the increase of the tissue impedance. The model is further used to investigate whether purposely terminating the treatment for a while allowing diffusion of the liquid water into the evaporated region would help. Results show it has no obvious improvement enlarging the treatment volume. Treatment with the cooled-tip electrode is also studied. It is found that the cooling conditions of the inside agent greatly affect the water loss pattern. When the convection coefficient of the cooling agent increases, excessive evaporation will start from near the central axis of the tissue cylinder instead of the edge of the electrode, and the coagulation volume obviously enlarges before a sudden increase of the impedance. It is also found that a higher convection coefficient will extend the treatment time. Though the sudden increase of the tissue impedance could be delayed by a larger convection coefficient; the rate of the impedance increase is also more dramatic compared to the case with smaller convection

Meta-analysis of bipolar radiofrequency endometrial ablation versus thermal balloon endometrial ablation for the treatment of heavy menstrual bleeding.

Science.gov (United States)

Zhai, Yan; Zhang, Zihan; Wang, Wei; Zheng, Tingping; Zhang, Huili

2018-01-01

Heavy menstrual bleeding is a common problem that can severely affect quality of life. To compare bipolar radiofrequency endometrial ablation and thermal balloon ablation for heavy menstrual bleeding in terms of efficacy and health-related quality of life (HRQoL). Online registries were systematically searched using relevant terms without language restriction from inception to November 24, 2016. Randomized control trials or cohort studies of women with heavy menstrual bleeding comparing the efficacy of two treatments were eligible. Data were extracted. Results were expressed as risk ratios (RRs) or weighted mean differences (WMDs) with 95% confidence intervals (CIs). Six studies involving 901 patients were included. Amenorrhea rate at 12 months was significantly higher after bipolar radiofrequency endometrial ablation than after thermal balloon ablation (RR 2.73, 95% CI 2.00-3.73). However, no difference at 12 months was noted for dysmenorrhea (RR 1.04, 95% CI 0.68-1.58) or treatment failure (RR 0.78, 95% CI 0.38-1.60). The only significant difference for HRQoL outcomes was for change in SAQ pleasure score (12 months: WMD -3.51, 95% CI -5.42 to -1.60). Bipolar radiofrequency endometrial ablation and thermal balloon ablation reduce menstrual loss and improve quality of life. However, bipolar radiofrequency endometrial ablation is more effective in terms of amenorrhea rate and SAQ pleasure. © 2017 International Federation of Gynecology and Obstetrics.

Microplasma radiofrequency technology combined with triamcinolone improved the therapeutic effect on Chinese patients with hypertrophic scar and reduced the risk of tissue atrophy.

Science.gov (United States)

Yu, Shui; Li, Hengjin

2016-01-01

The current study aimed to assess the value of microplasma radiofrequency technology combined with triamcinolone for the therapy of Chinese patients with hypertrophic scar. A total of 120 participants with hypertrophic scars were enrolled in the current study. Participants were divided into two groups based on sex, and then randomly and evenly divided into four groups (Groups A, B, C, and D). Participants in Group A received microplasma radiofrequency technology combined with triamcinolone. Participants in Group B received microplasma radiofrequency technology combined with normal saline. Participants in Groups C and D received triamcinolone (40 and 10 mg/mL) injected directly into scar. Experienced physicians evaluated the condition of scars according to the Vancouver Scar Scale 1 month before and after the therapy. There was no difference in age, sex, area, height and location of scars, and Vancouver Scar Scale scores before the therapy between any groups (P>0.05 for all). Vancouver Scar Scale scores after the therapy were significantly lower than those before the therapy in all groups (P0.05 for all). Incidences of tissue atrophy after the therapy were significantly lower in Groups A and B than in Group C (P0.05 for all). Microplasma radiofrequency technology combined with triamcinolone improved the therapeutic effect on Chinese patients with hypertrophic scar and reduced the risk of tissue atrophy compared with the use of either microplasma radiofrequency technology or triamcinolone injection alone.