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Sample records for chest-wall impedance algorithms

  1. Algorithm of chest wall keloid treatment.

    PubMed

    Long, Xiao; Zhang, Mingzi; Wang, Yang; Zhao, Ru; Wang, Youbin; Wang, Xiaojun

    2016-08-01

    Keloids are common in the Asian population. Multiple or huge keloids can appear on the chest wall because of its tendency to develop acne, sebaceous cyst, etc. It is difficult to find an ideal treatment for keloids in this area due to the limit of local soft tissues and higher recurrence rate. This study aims at establishing an individualized protocol that could be easily applied according to the size and number of chest wall keloids.A total of 445 patients received various methods (4 protocols) of treatment in our department from September 2006 to September 2012 according to the size and number of their chest wall keloids. All of the patients received adjuvant radiotherapy in our hospital. Patient and Observer Scar Assessment Scale (POSAS) was used to assess the treatment effect by both doctors and patients. With mean follow-up time of 13 months (range: 6-18 months), 362 patients participated in the assessment of POSAS with doctors.Both the doctors and the patients themselves used POSAS to evaluate the treatment effect. The recurrence rate was 0.83%. There was an obvious significant difference (P < 0.001) between the before-surgery score and the after-surgery score from both doctors and patients, indicating that both doctors and patients were satisfied with the treatment effect.Our preliminary clinical result indicates that good clinical results could be achieved by choosing the proper method in this algorithm for Chinese patients with chest wall keloids. This algorithm could play a guiding role for surgeons when dealing with chest wall keloid treatment. PMID:27583896

  2. Algorithm of chest wall keloid treatment

    PubMed Central

    Long, Xiao; Zhang, Mingzi; Wang, Yang; Zhao, Ru; Wang, Youbin; Wang, Xiaojun

    2016-01-01

    Abstract Keloids are common in the Asian population. Multiple or huge keloids can appear on the chest wall because of its tendency to develop acne, sebaceous cyst, etc. It is difficult to find an ideal treatment for keloids in this area due to the limit of local soft tissues and higher recurrence rate. This study aims at establishing an individualized protocol that could be easily applied according to the size and number of chest wall keloids. A total of 445 patients received various methods (4 protocols) of treatment in our department from September 2006 to September 2012 according to the size and number of their chest wall keloids. All of the patients received adjuvant radiotherapy in our hospital. Patient and Observer Scar Assessment Scale (POSAS) was used to assess the treatment effect by both doctors and patients. With mean follow-up time of 13 months (range: 6–18 months), 362 patients participated in the assessment of POSAS with doctors. Both the doctors and the patients themselves used POSAS to evaluate the treatment effect. The recurrence rate was 0.83%. There was an obvious significant difference (P < 0.001) between the before-surgery score and the after-surgery score from both doctors and patients, indicating that both doctors and patients were satisfied with the treatment effect. Our preliminary clinical result indicates that good clinical results could be achieved by choosing the proper method in this algorithm for Chinese patients with chest wall keloids. This algorithm could play a guiding role for surgeons when dealing with chest wall keloid treatment. PMID:27583896

  3. Total and local impedances of the chest wall up to 10 Hz.

    PubMed

    Barnas, G M; Yoshino, K; Fredberg, J; Kikuchi, Y; Loring, S H; Mead, J

    1990-04-01

    To understand how bical mechanical chest wall (CW) properties are related to those of the CW as a whole, we measured esophageal and gastric pressures, CW volume changes (measured with a head-out body plethysmograph), and anteroposterior and transverse CW diameter changes (measured with magnetometers attached to the surface) during sinusoidal forcing at the mouth (2.5% vital capacity, 0.5-10 Hz) in four healthy subjects. Total CW resistance decreased sharply as frequency rose to 3-4 Hz and remained relatively constant at higher frequencies. Total CW reactance became less negative with increasing frequency but showed no tendency to change sign. Above 2 Hz, diameters measured at different locations changed asynchronously between and within the rib cage and abdomen. "Local pathway impedances" (ratios of esophageal or gastric pressure to a rate of diameter change) showed frequency dependence similar to that of the total CW less than 3 Hz. Local pathway impedances increased during contraction of respiratory muscles acting on the pathway. We conclude that 1) total CW behavior is mainly a reflection of its individual local properties at less than or equal to 3 Hz, 2) local impedances within the rib cage or within the abdomen can change independently in some situations, and 3) asynchronies that develop within the CW during forcing greater than 3 Hz suggest that two compartments may be insufficient to describe CW properties from impedance measurements. PMID:2140827

  4. Musculoskeletal chest wall pain

    PubMed Central

    Fam, Adel G.; Smythe, Hugh A.

    1985-01-01

    The musculoskeletal structures of the thoracic wall and the neck are a relatively common source of chest pain. Pain arising from these structures is often mistaken for angina pectoris, pleurisy or other serious disorders. In this article the clinical features, pathogenesis and management of the various musculoskeletal chest wall disorders are discussed. The more common causes are costochondritis, traumatic muscle pain, trauma to the chest wall, “fibrositis” syndrome, referred pain, psychogenic regional pain syndrome, and arthritis involving articulations of the sternum, ribs and thoracic spine. Careful analysis of the history, physical findings and results of investigation is essential for precise diagnosis and effective treatment. ImagesFig. 3Fig. 4Fig. 5 PMID:4027804

  5. [Chest wall reconstruction after resection of malignant chest wall tumors].

    PubMed

    Ayabe, H; Oka, T; Akamine, S; Takahashi, T; Nagayasu, T

    1998-05-01

    Full-thickness chest wall resection is performed for complete removal of primary and secondary malignant chest wall tumors. Large defects of the chest wall after resection must be repaired to maintain adequate ventilation, to protect important intrathoracic structures, and to preserve cosmetic integrity. Various materials have been utilized over the years to replace the rigid chest wall. At present, Marlex mesh and a composite of Marlex mesh and methylmethacrylate are frequently used to reconstruct rigid chest wall defects. On the other hand, to replace the soft part of the chest wall and cover the rigid materials, pedicled muscle flaps, myocutaneous flaps, or omentum are used. Major pedicled flaps include the pectoralis major, rectus abdominis and latissimus dorsi muscular, and musculocutaneous flaps. Techniques are now available to repair any chest wall site, and to restore chest continuity in patients whose tumors are curatively resected. PMID:9656244

  6. Painful Chest Wall Swellings: Tietze Syndrome or Chest Wall Tumor?

    PubMed

    Kaplan, Tevfik; Gunal, Nesimi; Gulbahar, Gultekin; Kocer, Bulent; Han, Serdar; Eryazgan, Mehmet Ali; Ozsoy, Arzu; Naldoken, Seniha; Alhan, Aslıhan; Sakinci, Unal

    2016-04-01

    Background Tietze syndrome (TS) is an inflammatory condition characterized by chest pain and swelling of costochondral junction. Primary chest wall tumors may mimic TS. In this article, we report our experience of approximately 121 patients initially diagnosed as TS and determined chest wall tumor in some cases at the follow-up. Methods This is a retrospective review of patients diagnosed as TS by clinical examination, chest X-ray, electrocardiogram, routine laboratory tests, and computed tomography (CT) of chest: all treated and followed up between March 2001 and July 2012. There were 121 cases (41 males and 80 females; mean age, 39.6 ± 3.2 years) of TS. Results In 27 patients with initial normal radiological findings, the size of swellings had doubled during the follow-up period (mean, 8.51 ± 2.15 months). These patients were reevaluated with chest CT and bone scintigraphy and then early diagnostic biopsy was performed. Pathologic examination revealed primary chest wall tumor in 13 patients (5 malignant, 8 benign). CT had a sensitivity of 92.3% and a specificity of 64.2% in detection of tumors (kappa: 0.56, p = 0.002), whereas the sensitivity and the specificity of bone scan were 84.6 and 35.7%, respectively (kappa: 0.199, p = 0.385). Conclusion Primary chest wall tumors could mimic TS. Bone scintigraphy or CT is not specific enough to determine malignant and other benign disorders of costochondral junction. Therefore, clinicians should follow TS patients more closely, and in case of increasing size of swelling, early diagnostic biopsy should be considered. PMID:25742551

  7. Chest wall resection for extrapulmonary tumor.

    PubMed

    Long, W P; Kline, R; Levine, E A

    1997-09-01

    Despite progress in early detection of breast cancer, a minority of women continue to present with extensive disease which may necessitate chest wall resection. Between 1992 and 1996, 14 patients were treated by surgical resection of the chest wall and reconstruction by the LSU Sections of Surgical Oncology and Plastic Surgery. Indications included resection of primary tumor, resection of recurrent tumor, and resection of radiation therapy induced damage to the chest wall. We report chest wall excision and reconstruction with no operative mortality and minor surgical morbidity in 21% of cases. Local control was achieved in 13 of 14 cases. Additionally we report uniform success in the palliation of ulcerating, painful, or infected chest wall lesions. Approximately 25% of patients treated for breast cancer and followed up for more than 6 months have remained free of disease. Chest wall resection is a useful modality in selected patients with extensive disease. PMID:9316348

  8. Classification of chest wall diseases.

    PubMed

    Pozzi, E; Gulotta, C

    1993-01-01

    Several disorders of the thoracic cage are known to cause respiratory failure, by means of relatively simple mechanisms, such as the increased work of breathing, which results in alveolar hypoventilation. A variety of pathogenic mechanisms may be considered, as functions of the types of thoracic disorders present. As causes of these additional potential mechanisms, we considered the following: 1) ventilation-perfusion (V/Q) inhomogeneity; 2) inability to cough; 3) malformation or acquired defect of the respiratory centres; and 4) excess blood volume and fluid retention, which aggravate work of breathing and V/Q inhomogeneity. All of these disorders can be grouped into two major categories (which nevertheless have some of the pathophysiology in common): the mechanical syndrome and the neuromuscular or paralytic syndrome. In this paper we discuss chest wall diseases falling into the first category; namely, kyphoscoliosis, fibrothorax, thoracoplasty, ankylosing spondylitis and obesity-hypoventilation. Congenital deformities of the thoracic cage, which do not have important effects on ventilatory apparatus (e.g. pectus excavatum and pectus carinatum), were also considered. PMID:8472068

  9. Intercostal hemangioma of the chest wall

    PubMed Central

    Hamzík, Julian

    2016-01-01

    The authors describe a case of a 36-year-old patient who had six months’ pain of the thoracic spine and left chest. A soft slowly growing resistance was present on the dorso-lateral side of the left chest wall, in the range of the seventh to ninth rib. According to the medical history, the patient did not have any prior trauma and malignancy. A well-defined tumor of the left chest wall with calcifications, which grew to the seventh and eighth intercostal space, was present on computed tomography (CT) and magnetic resonance (MR) scans. The patient underwent resection of the tumor with the chest wall and reconstruction with polypropylene mesh. Histologically, it was a venous hemangioma, one of very rare tumors of the chest wall. PMID:27212983

  10. Chest wall reconstruction after resection using hernia repair piece

    PubMed Central

    Wu, Yimin; Zhang, Guofei; Zhu, Zhouyu

    2016-01-01

    Reconstruction of chest wall tumor is very important link of chest wall tumor resection. Many implants have been reported to be used to reconstruct the chest wall, such as steelwire, titanium mesh and polypropylene mesh. It is really hard for clinicians to decide which implant is the best one to replace the chest wall. We herein report a 68-year-old man who had underwent a chest wall reconstruction with a hernia repair piece and a Dacron hernia repair piece. The patient has maintained an excellent cosmetic and functional outcome since surgery, which proves that the hernia piece still has its place in reconstruction of chest wall. PMID:27293859

  11. Effect of gravity on chest wall mechanics.

    PubMed

    Bettinelli, D; Kays, C; Bailliart, O; Capderou, A; Techoueyres, P; Lachaud, J L; Vaïda, P; Miserocchi, G

    2002-02-01

    Chest wall mechanics was studied in four subjects on changing gravity in the craniocaudal direction (G(z)) during parabolic flights. The thorax appears very compliant at 0 G(z): its recoil changes only from -2 to 2 cmH(2)O in the volume range of 30-70% vital capacity (VC). Increasing G(z) from 0 to 1 and 1.8 G(z) progressively shifted the volume-pressure curve of the chest wall to the left and also caused a fivefold exponential decrease in compliance. For lung volume <30% VC, gravity has an inspiratory effect, but this effect is much larger going from 0 to 1 G(z) than from 1 to 1.8 G(z). For a volume from 30 to 70% VC, the effect is inspiratory going from 0 to 1 G(z) but expiratory from 1 to 1.8 G(z). For a volume greater than approximately 70% VC, gravity always has an expiratory effect. The data suggest that the chest wall does not behave as a linear system when exposed to changing gravity, as the effect depends on both chest wall volume and magnitude of G(z). PMID:11796685

  12. Salmonella typhimurium abscess of the chest wall

    PubMed Central

    Tonziello, Gilda; Valentinotti, Romina; Arbore, Enrico; Cassetti, Paolo; Luzzati, Roberto

    2013-01-01

    Patient: Male, 73 Final Diagnosis: Salmonella typhimurium abscess of the chest wall Symptoms: — Medication: Ciprofloxacin Clinical Procedure:— Specialty: Infectious Diseases Objective: Unusual clinical course Background: Non-typhoid Salmonella extra-intestinal infections usually develop in infants and in adult patients with pre-existing predisposing conditions. Blood stream infections and urinary tract infections are the most common clinical presentations, but other sites of infection may be involved as well. Case Report: We describe a case of invasive salmonellosis caused by Salmonella typhimurium involving the chest wall in a 73-year-old man. The patient had suffered from gastroenteritis followed by left basal pneumonia with pleural effusion 7 weeks before. The CT scan of the chest wall showed a pericostal abscess with shirt-stud morphology near the left last cartilaginous arch. The abscess was surgically drained and patient was cured after a 40-day ciprofloxacin treatment. Conclusions: A review of the literature on extra-intestinal non-typhoid salmonellosis shows that pleuropulmonary and soft-tissue infections are uncommon. We argue that non-typhoid Salmonella might be considered as a possible cause of chest wall abscess in individuals with recent history of gastroenteritis complicated by pneumonia and pleural effusion. PMID:24298305

  13. Uncommon Flaps for Chest Wall Reconstruction

    PubMed Central

    Matros, Evan; Disa, Joseph J.

    2011-01-01

    The omentum, external oblique musculocutaneous, and thoracoepigastric flaps are uncommonly used for chest wall reconstruction. Nevertheless, awareness and knowledge of these flaps is essential for reconstructive surgeons because they fill specific niche indications or serve as lifeboats when workhorse flaps are unavailable. The current report describes the anatomic basis, technical aspects of flap elevation, and indications for these unusual flaps. PMID:22294943

  14. [Chest Wall Reconstruction Using Titanium Plates Sandwiched Between Sheets after Resection of Chest Wall Chondrosarcoma].

    PubMed

    Endoh, Makoto; Oizumi, Hiroyuki; Kato, Hirohisa; Suzuki, Jun; Watarai, Hikaru; Hamada, Akira; Suzuki, Katsuyuki; Takahashi, Ai; Nakahashi, Kenta; Sugawara, Masato; Tsuchiya, Takashi; Sadahiro, Mitsuaki

    2016-07-01

    Extensive chest wall resection carries the risk of difficult reconstruction and surgical complications. We report our experience on chest wall reconstruction using titanium plates for a wide thoracic defect after tumor resection. A 74-year-old man was diagnosed with chondrosarcoma of the 6th rib on the right. He needed extensive chest wall resection because of skip lesions on 4th rib noted on operative inspection, leaving a defect measuring 33 × 20 cm. Reconstruction using 5 transverse titanium plates sandwiched between an expanded polytetrafluoroethylene patch and a polypropylene mesh sheet stabilized the chest wall. This reconstruction allowed successful separation from ventilatory support after operation. The postoperative course was uneventful, and he was discharged on postoperative day 20. The advantages of this form of reconstruction over conventional prostheses are rigidity, and stability and usability. PMID:27365062

  15. Normalized mean shapes and reference index values for computerized quantitative assessment indices of chest wall deformities

    NASA Astrophysics Data System (ADS)

    Kim, Ho Chul; Park, Man Sik; Lee, Seong Keon; Nam, Ki Chang; Park, Hyung Joo; Kim, Min Gi; Song, Jae-Jun; Choi, Hyuk

    2015-11-01

    We previously proposed a computerized index (eccentricity index [EI]) for chest-wall deformity measurements, such as pectus excavatum. We sought to define mean shapes based on normal chest walls and to propose for computerized index reference values of that are used in the quantitative analysis of the severity of chest-wall deformities. A total of 584 patients were classified into 18 groups, and a database of their chest-wall computed tomography (CT) scan images was constructed. The boundaries of the chest wall were extracted by using a segmentation algorithm, and the mean shapes were subsequently developed. The reference index values were calculated from the developed mean shapes. Reference index values for the EI were compared with a conventional index, the Haller index (HI). A close association has been shown between the two indices in multiple subjects (r = 0.974, P < 0.001). The newly developed mean shapes and reference index values supply both reliability and objectivity to the diagnosis, analysis, and treatment of chest-wall deformities. They promise to be highly useful in clinical settings.

  16. [Chest wall tuberculosis: report of 3 cases].

    PubMed

    Zidane, A; Bakzaza, O; Afandi, O; Baiz, Y; Chafik, A

    2015-10-01

    Despite the dramatic decline in the incidence of tuberculosis during the last decades, the disease remains a significant public health problem especially in developing countries. Chest wall tuberculosis is a very rare location. Clinically, it can present as a pyogenic abscess or soft tumor, making diagnosis difficult, particularly in the absence of warning signs. Optimal therapeutic management is controversial. Medical treatment alone in often insufficient and must be associated with a surgical excision or debridement. PMID:25725600

  17. Reconstruction of full thickness chest wall defects.

    PubMed Central

    Morgan, R F; Edgerton, M T; Wanebo, H J; Daniel, T M; Spotnitz, W D; Kron, I L

    1988-01-01

    Over the last 5 years, 14 patients were treated by wide en bloc resection of chest wall tumors with primary reconstruction. There were nine females and five male patients with an age range of 31-77 years. All patients had a skeletal resection of the chest wall. An average of 3.9 ribs were resected in the patients treated. In three patients a partial sternectomy was carried out in conjunction with the rib resections. Chest wall skeletal defects were reconstructed with Prolene mesh, which was placed under tension. Soft tissue reconstruction utilized selected portions of the latissimus dorsi musculocutaneous territory with fasciocutaneous extensions beyond the muscle itself. Primary healing was obtained in all patients and secondary procedures were not required. The average hospitalization was 23 days. All patients survived the resection and reconstruction and were alive 30 days after operation. In selected patients the preservation of a portion of the innervated muscle in situ or the transfer of the muscle with the preservation of its resting length has maintained the majority of the muscle function. Images Fig. 3A. Fig. 3C. Fig. 3D. Fig. 4A. Fig. 4C. Fig. 4D. Fig. 4E. Fig. 5A. Fig. 5B. Fig. 5D. Fig. 6A. Fig. 6C. Fig. 6D. Fig. 6E. Fig. 6F. Fig. 6G. Fig. 6H. PMID:3389939

  18. Reconstruction of full thickness chest wall defects.

    PubMed

    Morgan, R F; Edgerton, M T; Wanebo, H J; Daniel, T M; Spotnitz, W D; Kron, I L

    1988-06-01

    Over the last 5 years, 14 patients were treated by wide en bloc resection of chest wall tumors with primary reconstruction. There were nine females and five male patients with an age range of 31-77 years. All patients had a skeletal resection of the chest wall. An average of 3.9 ribs were resected in the patients treated. In three patients a partial sternectomy was carried out in conjunction with the rib resections. Chest wall skeletal defects were reconstructed with Prolene mesh, which was placed under tension. Soft tissue reconstruction utilized selected portions of the latissimus dorsi musculocutaneous territory with fasciocutaneous extensions beyond the muscle itself. Primary healing was obtained in all patients and secondary procedures were not required. The average hospitalization was 23 days. All patients survived the resection and reconstruction and were alive 30 days after operation. In selected patients the preservation of a portion of the innervated muscle in situ or the transfer of the muscle with the preservation of its resting length has maintained the majority of the muscle function. PMID:3389939

  19. Solitary fibrous tumour of the chest wall.

    PubMed

    Mohtarrudin, N; Nor Hanipah, Z; Mohd Dusa, N

    2016-04-01

    Extrapleural solitary fibrous tumours (SFTs) are rare tumours characterized by patternless spindle cells with haemangiopericytoma-like vascular spaces. Previously the tumours have been classified as haemangiopericytoma, an entity that is now considered obsolete. We report a case of extrapleural SFT arising in the soft tissue of the chest wall. The patient was a 31-year-old Malay lady presenting with a mobile swelling of the right chest wall for more than five years. During excision the tumour was noted to be well-circumscribed and yellowish in colour, giving an impression of lipoma. Microscopically, the tumour had patternless architecture, characterized by hypocellular and hypercellular areas. It was composed of uniform, spindle-shaped cells displaying oval nuclei, inconspicuous nucleoli, pale cytoplasm and indistinct cell borders. The mitotic count was 2 per 10 HPF. Branching, medium-sized thin-walled blood vessels in a haemangiopericytomatous growth pattern, some with hyalinised wall were identified. The neoplastic cells were immunoreactive to CD99 and CD34 and were non-immunoreactive to Desmin, Smooth Muscle Actin, S100 protein and EMA. We elucidate the challenges in diagnosing this tumour in this unusual location. PMID:27126667

  20. Chest wall tumour following iodized talc pleurodesis

    PubMed Central

    Jackson, John W.; Bennett, M. H.

    1973-01-01

    Jackson, J. W., and Bennett, M. H. (1973).Thorax, 28, 788-793. Chest wall tumour following iodized talc pleurodesis. A man of 37 had an iodized talc pleurodesis carried out for recurrent spontaneous pneumothorax. There was no history of industrial exposure to asbestos. Two years later he presented with pain in the right chest and radiographs at that time showed some localized pleural thickening at the site of the thoracoscopy cannulation for introduction of talc. A provisional diagnosis of talc granuloma, chemical abscess or tumour was made and exploratory thoracotomy revealed a tumour involving the chest wall, lung, and pleura which, on histological examination, showed adenocarcinoma of varying degrees of differentiation and in some parts also presenting a more squamoid appearance. Numerous doubly refractile talc particles were intimately associated with the tumour and fibrous tissue. Shortly after excision the patient developed evidence of systemic dissemination of the disease and died four months later. The possibility of this tumour being induced by the talc is discussed. A brief review is made of the various forms of talc used in surgery over the past 40 years and attention is drawn to the significance of the proportion of asbestos mineral which is present in talc as mined in various parts of the world. We do not consider that this is a case of mesothelioma of the pleura. Images PMID:4787992

  1. [Functional Outcome after Chest Wall Stabilisation].

    PubMed

    Kyriss, T; Lenz, U; Friedel, G

    2016-09-01

    This overview reviews the current literature to compare the functional results after surgical and conservative treatment of patients with flail chest and multiple rib fractures. Regarding functional aspects, patients in the early phase after a thoracic trauma are those that benefit most from the stabilisation of the chest wall by internal fixation of the ribs. Patients recover faster from restrictive respiratory disorders, have less pain and return to the workplace earlier after an operation compared with those that receive conservative treatment. In the medium term, however, patients that are treated conservatively also achieve normal pulmonary function values and become free of pain. The period of convalescence after blunt thoracic trauma is generally underestimated. Future studies of the functional outcome after severe chest injuries should take this into account and the development of functional parameters should be monitored for at least 24 months. A prospective data collection of early and long-term surgical results in registries would be suitable to evaluate benefits and indications of chest wall stabilisation. PMID:27607891

  2. Results of chest wall resection and reconstruction in 162 patients with benign and malignant chest wall disease

    PubMed Central

    Aghajanzadeh, Manoucheher; Alavy, Ali; Taskindost, Mehrdad; Pourrasouly, Zahra; Aghajanzadeh, Gilda; massahnia, Sara

    2010-01-01

    Background Chest wall resection is a complicated treatment modality with significant morbidity. The purpose of this study is to report our experience with chest wall resections and reconstructions. Methods The records of all patients undergoing chest wall resection and reconstruction were reviewed. Diagnostic procedures, surgical indications, the location and size of the chest wall defect, performance of lung resection, the type of prosthesis, and postoperative complications were recorded. Results From 1997 to 2008, 162 patients underwent chest wall resection.113 (70%) of patients were male. Age of patients was 14 to 69 years. The most common indications for surgery were primary chest wall tumors. The most common localized chest wall mass has been seen in the anterior chest wall. Sternal resection was required in 22 patients, Lung resection in 15 patients, Rigid prosthetic reconstruction has been used in 20 patients and nonrigid prolene mesh and Marlex mesh in 40 patients. Mean intensive care unit stay was 8 days. In-hospital mortality was 3.7 % (six patients). Conclusions Chest wall resection and reconstruction with Bone cement sandwich with mesh can be performed as a safe and effective surgical procedure for major chest wall defects and respiratory failure is lower in prosthetic reconstruction patients than previously reported (6). PMID:22263024

  3. Mechanical properties of lungs and chest wall during spontaneous breathing.

    PubMed

    Nagels, J; Làndsér, F J; van der Linden, L; Clément, J; Van de Woestijne, K P

    1980-09-01

    Using a forced oscillation technique, we measured the resistance (Rrs) and reactance (Xrs) of the respiratory system between 2 and 32 Hz at three different lung volumes in 15 healthy subjects and 7 patients with chronic obstructive pulmonary disease. Rrs and Xrs were partitioned, by means of a pressure recording in the esophagus, into the resistance and reactance of lung and airways (L) and the chest wall. The measurements were validated by checking the adequacy of the frequency response of the esophagus, by the lack of difference between thoracic and mouth flow, by an estimation of the error introduced by the shunt impedance of the cheeks, and by comparisons with the values of pulmonary compliance and resistance determined in the same subjects with classical techniques. In both healthy subjects and patients, the chest wall has a low resistance that increases somewhat at low lung volumes and behaves functionally as a two-compartment system, with low capacitance at frequencies exceeding 4 Hz. Rrs varies with lung volume and is markedly frequency dependent in patients; both phenomena are due primarily to corresponding variations of RL. In healthy subjects, at and above functional residual capacity (FRC) level, the lungs behave as a one-compartment system, the reactance of which is mainly determined by the gaseous inertance, at least beyond 2 Hz. In patients and in healthy subjects breathing below FRC, the observed frequency dependence of resistance and the simultaneous increase in resonant frequency can be simulated satisfactorily by Mead's two-compartment model, assuming a large increase in peripheral airways resistance. PMID:7204163

  4. [NECROTIZING FASCIITIS OF THE CHEST WALL].

    PubMed

    Farah, Raymond; Asla, Husam

    2016-04-01

    Necrotizing fasciitis (NF) is a bacterial dermo-hypodermitis affecting the soft tissue and muscular fascia. It is an uncommon and severe infection caused by microorganisms called 'flesh eating bacteria', mainly represented by group A beta-haemolytic streptococcus. NF remains a life-threatening condition associated with a high mortality rate. Its location on the chest wall is extremely rare. The few reported cases are subsequent to thoracic drainage, lung surgery or esophageal resection. This is a case report of an 80-year old female with comorbidity of heart disease, a past history of coronary artery by-pass and diabetes. She was admitted to the emergency room with acute NF of the chest and shortly after diagnosis, the patient died. Due to the fast decline observed in this disease, we would like to emphasize the importance of early recognition and diagnosis. PMID:27323534

  5. [Dedifferentiated Chondrosarcoma of the Chest Wall].

    PubMed

    Saitoh, Genkichi; Yoneshima, Yasuto; Nakamura, Toshihiko; Kitagawa, Dai; Kinjo, Nao; Ohgaki, Kippei; Maehara, Shinichiro; Teramoto, Seiichi; Adachi, Eisuke; Ikeda, Yoichi; Mine, Mari

    2016-08-01

    A 79-year-old man complaining of an anterior chest mass with pain had an abnormal shadow on chest X-ray. A mass, 7 cm in size, with destruction of the right 4th rib was found on chest computed tomography. A F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) corresponding to the lesion showed an abnormal accumulation of FDG with the standardized uptake value(SUV) max=16.19. A malignant tumor of the chest wall origin was suspected and the tumor was resected with the 3th, 4th, and 5th ribs. Histologically, the tumor was diagnosed as dedifferentiated chondrosarcoma. He died of local recurrence about 5 months after the operation. PMID:27476566

  6. Multidisciplinary Oncoplastic Approach Reduces Infection in Chest Wall Resection and Reconstruction for Malignant Chest Wall Tumors

    PubMed Central

    Malahias, Marco N.; Balasubramanian, Balapathiran; Djearaman, Madava G.; Naidu, Babu; Grainger, Melvin F.; Kalkat, Maninder

    2016-01-01

    Background: Management of complex thoracic defects post tumor extipiration is challenging because of the nature of pathology, the radical approach, and the insertion of prosthetic material required for biomechanical stability. Wound complications pose a significant problem that can have detrimental effect on patient outcome. The authors outline an institutional experience of a multidisciplinary thoracic oncoplastic approach to improve outcomes. Methods: Prospectively collected data from 71 consecutive patients treated with chest wall resection and reconstruction were analyzed (2009–2015). The demographic data, comorbidities, operative details, and outcomes with special focus on wound infection were recorded. All patients were managed in a multidisciplinary approach to optimize perioperative surgical planning. Results: Pathology included sarcoma (78%), locally advanced breast cancer (15%), and desmoids (6%), with age ranging from 17 to 82 years (median, 42 years) and preponderance of female patients (n = 44). Chest wall defects were located anterior and anterolateral (77.5%), posterior (8.4%), and apical axillary (10%) with skeletal defect size ranging from 56 to 600 cm2 (mean, 154 cm2). Bony reconstruction was performed using polyprolene mesh, methyl methacrylate prosthesis, and titanium plates. Soft tissue reconstructions depended on size, location, and flap availability and were achieved using regional, distant, and free tissue flaps. The postoperative follow-up ranged from 5 to 70 months (median, 32 months). All flaps survived with good functional and aesthetic outcome, whereas 2 patients experienced surgical site infection (2.8%). Conclusions: Multidisciplinary thoracic oncoplastic maximizes outcome for patients with large resection of chest wall tumors with reduction in surgical site infection and wound complications particularly in association with rigid skeletal chest wall reconstruction. PMID:27536488

  7. An optical tomography method that accounts for a titled chest-wall in breast imaging

    NASA Astrophysics Data System (ADS)

    Ardeshirpour, Yasaman; Huang, Minming; Zhu, Quing

    2009-02-01

    The chest-wall underneath the breast tissue distorts the diffused near infra-red light measured at distant source-detector pairs. Common image reconstruction method consider the media as homogeneous and applying the semi-infinite model. In this paper, we have compared the performance of our two-layer model with semi-infinite model by simulation and a clinical case. The results show that when the chest wall has significant effect on the measurement data, a benign lesion with low absorption can be misled as a malignant case with high absorption by using semi-infinite model. We have also shown the influence of mismatch geometry of breast tissue and chest-wall at lesion and reference sides on the reconstructed image and a correction method has been introduced to reduce these effects. With the assistance of two orthogonal co-registered ultrasounds, the geometry of the breast tissue and chest wall interface can be determined and modeled as a two-layer medium with 3D finite element mesh. Since numerical algorithms based on finite element methods (FEM) are suitable for complex geometry and boundary conditions, this method is adapted to model the chestwall. Four parameters of bulk absorption and reduced scattering coefficients of the first and second layers are estimated and used to characterize the optical properties of the medium. We used a finite element model based on modified born approximation for image reconstruction. A mismatch correction algorithm has been applied to compensate the mismatch geometry of the breast tissue and chest-wall interface at the reference and the lesion side.

  8. Chest wall mechanics in sustained microgravity.

    PubMed

    Wantier, M; Estenne, M; Verbanck, S; Prisk, G K; Paiva, M

    1998-06-01

    We assessed the effects of sustained weightlessness on chest wall mechanics in five astronauts who were studied before, during, and after the 10-day Spacelab D-2 mission (n = 3) and the 180-day Euromir-95 mission (n = 2). We measured flow and pressure at the mouth and rib cage and abdominal volumes during resting breathing and during a relaxation maneuver from midinspiratory capacity to functional residual capacity. Microgravity produced marked and consistent changes (Delta) in the contribution of the abdomen to tidal volume [DeltaVab/(DeltaVab + DeltaVrc), where Vab is abdominal volume and Vrc is rib cage volume], which increased from 30.7 +/- 3. 5 (SE)% at 1 G head-to-foot acceleration to 58.3 +/- 5.7% at 0 G head-to-foot acceleration (P < 0.005). Values of DeltaVab/(DeltaVab + DeltaVrc) did not change significantly during the 180 days of the Euromir mission, but in the two subjects DeltaVab/(DeltaVab + DeltaVrc) was greater on postflight day 1 than on subsequent postflight days or preflight. In the two subjects who produced satisfactory relaxation maneuvers, the slope of the Konno-Mead plot decreased in microgravity; this decrease was entirely accounted for by an increase in abdominal compliance because rib cage compliance did not change. These alterations are similar to those previously reported during short periods of weightlessness inside aircrafts flying parabolic trajectories. They are also qualitatively similar to those observed on going from upright to supine posture; however, in contrast to microgravity, such postural change reduces rib cage compliance. PMID:9609801

  9. Lung and chest wall mechanics in microgravity.

    PubMed

    Edyvean, J; Estenne, M; Paiva, M; Engel, L A

    1991-11-01

    We studied the effect of 15-20 s of weightlessness on lung, chest wall, and abdominal mechanics in five normal subjects inside an aircraft flying repeated parabolic trajectories. We measured flow at the mouth, thoracoabdominal and compartmental volume changes, and gastric pressure (Pga). In two subjects, esophageal pressures were measured as well, allowing for estimates of transdiaphragmatic pressure (Pdi). In all subjects functional residual capacity at 0 Gz decreased by 244 +/- 31 ml as a result of the inward displacement of the abdomen. End-expiratory Pga decreased from 6.8 +/- 0.8 cmH2O at 1 Gz to 2.5 +/- 0.3 cmH2O at Gz (P less than 0.005). Abdominal contribution to tidal volume increased from 0.33 +/- 0.05 to 0.51 +/- 0.04 at 0 Gz (P less than 0.001) but delta Pga showed no consistent change. Hence abdominal compliance increased from 43 +/- 9 to 70 +/- 10 ml/cmH2O (P less than 0.05). There was no consistent effect of Gz on tidal swings of Pdi, on pulmonary resistance and dynamic compliance, or on any of the timing parameters determining the temporal pattern of breathing. The results indicate that at 0 G respiratory mechanics are intermediate between those in the upright and supine postures at 1 G. In addition, analysis of end-expiratory pressures suggests that during weightlessness intra-abdominal pressure is zero, the diaphragm is passively tensed, and a residual small pleural pressure gradient may be present. PMID:1761497

  10. Chest wall mechanics in sustained microgravity

    NASA Technical Reports Server (NTRS)

    Wantier, M.; Estenne, M.; Verbanck, S.; Prisk, G. K.; Paiva, M.; West, J. B. (Principal Investigator)

    1998-01-01

    We assessed the effects of sustained weightlessness on chest wall mechanics in five astronauts who were studied before, during, and after the 10-day Spacelab D-2 mission (n = 3) and the 180-day Euromir-95 mission (n = 2). We measured flow and pressure at the mouth and rib cage and abdominal volumes during resting breathing and during a relaxation maneuver from midinspiratory capacity to functional residual capacity. Microgravity produced marked and consistent changes (Delta) in the contribution of the abdomen to tidal volume [DeltaVab/(DeltaVab + DeltaVrc), where Vab is abdominal volume and Vrc is rib cage volume], which increased from 30.7 +/- 3. 5 (SE)% at 1 G head-to-foot acceleration to 58.3 +/- 5.7% at 0 G head-to-foot acceleration (P < 0.005). Values of DeltaVab/(DeltaVab + DeltaVrc) did not change significantly during the 180 days of the Euromir mission, but in the two subjects DeltaVab/(DeltaVab + DeltaVrc) was greater on postflight day 1 than on subsequent postflight days or preflight. In the two subjects who produced satisfactory relaxation maneuvers, the slope of the Konno-Mead plot decreased in microgravity; this decrease was entirely accounted for by an increase in abdominal compliance because rib cage compliance did not change. These alterations are similar to those previously reported during short periods of weightlessness inside aircrafts flying parabolic trajectories. They are also qualitatively similar to those observed on going from upright to supine posture; however, in contrast to microgravity, such postural change reduces rib cage compliance.

  11. Chest Wall Dissemination of Nocardiosis after Percutaneous Transthoracic Needle Biopsy

    SciTech Connect

    Shimamoto, Hiroshi Inaba, Yoshitaka; Yamaura, Hidekazu; Sato, Yozo; Kamiya, Mika; Miyazaki, Masaya; Arai, Yasuaki; Horio, Yoshitsugu

    2007-07-15

    We described a case of chest wall dissemination after percutaneous transthoracic needle biopsy. A 65-year-old man had a lung nodule which was suspected to be lung carcinoma. He underwent percutaneous transthoracic needle biopsy using an 18G semiautomated biopsy needle and pathologic diagnosis showed organizing pneumonia. Two months after the biopsy, chest wall dissemination occurred. Implantation of carcinoma along the biopsy route was suspected, but the mass was actually due to pulmonary nocardiosis.

  12. Chest wall segmentation in automated 3D breast ultrasound scans.

    PubMed

    Tan, Tao; Platel, Bram; Mann, Ritse M; Huisman, Henkjan; Karssemeijer, Nico

    2013-12-01

    In this paper, we present an automatic method to segment the chest wall in automated 3D breast ultrasound images. Determining the location of the chest wall in automated 3D breast ultrasound images is necessary in computer-aided detection systems to remove automatically detected cancer candidates beyond the chest wall and it can be of great help for inter- and intra-modal image registration. We show that the visible part of the chest wall in an automated 3D breast ultrasound image can be accurately modeled by a cylinder. We fit the surface of our cylinder model to a set of automatically detected rib-surface points. The detection of the rib-surface points is done by a classifier using features representing local image intensity patterns and presence of rib shadows. Due to attenuation of the ultrasound signal, a clear shadow is visible behind the ribs. Evaluation of our segmentation method is done by computing the distance of manually annotated rib points to the surface of the automatically detected chest wall. We examined the performance on images obtained with the two most common 3D breast ultrasound devices in the market. In a dataset of 142 images, the average mean distance of the annotated points to the segmented chest wall was 5.59 ± 3.08 mm. PMID:23273891

  13. Measurement of chest wall displacement based on terahertz wave

    NASA Astrophysics Data System (ADS)

    Li, Hui; Lv, Hao; Jiao, Teng; Lu, Guohua; Li, Sheng; Li, Zhao; Liu, Miao; Jing, Xijing; Wang, Jianqi

    2015-02-01

    Measurement of chest wall displacement is an important approach for measuring mechanics of chest wall, which has considerable significance for assessing respiratory system and diagnosing pulmonary diseases. However, existing optical methods for measuring chest wall displacement are inconvenient for some specific patients such as the female patients and the patients with bandaged chest. In this letter, we proposed a method for measuring chest wall displacement based on terahertz wave and established corresponding mathematic model and set up a terahertz measurement system. The main advantages of this method are that it can measure the chest wall displacement of the subjects without taking off clothes or arranging any markers. To validate this method and assess the performance of the terahertz system, in vitro, the displacement of a water module driven by a linear guide rail was measured by the terahertz system and compared with the actual displacement of the water module. The results showed that the waveforms measured with two methods have a good agreement, and the relative error is less than 5% and sufficiently good for measurement demands. In vivo, the synchronous experiment was performed on five human volunteers with the terahertz system and a respiratory belt transducer. The results demonstrate that this method has good performance and promising prospects for measuring chest wall displacement.

  14. Massive chest wall resection and reconstruction for malignant disease

    PubMed Central

    Foroulis, Christophoros N; Kleontas, Athanassios D; Tagarakis, George; Nana, Chryssoula; Alexiou, Ioannis; Grosomanidis, Vasilis; Tossios, Paschalis; Papadaki, Elena; Kioumis, Ioannis; Baka, Sofia; Zarogoulidis, Paul; Anastasiadis, Kyriakos

    2016-01-01

    Objective Malignant chest wall tumors are rare neoplasms. Resection with wide-free margins is an important prognostic factor, and massive chest wall resection and reconstruction are often necessary. A recent case series of 20 consecutive patients is reported in order to find any possible correlation between tumor histology, extent of resection, type of reconstruction, and adjuvant treatment with short- and long-term outcomes. Methods Twenty patients were submitted to chest wall resection and reconstruction for malignant chest wall neoplasms between 2006 and 2014. The mean age (ten males) was 59±4 years. The size and histology of the tumor, the technique of reconstruction, and the short- and long-term follow-up records were noted. Results The median maximum diameter of tumors was 10 cm (5.4–32 cm). Subtotal sternal resection was performed in nine cases, and the resection of multiple ribs was performed in eleven cases. The median area of chest wall defect was 108 cm2 (60–340 cm2). Histology revealed soft tissue, bone, and cartilage sarcomas in 16 cases (80%), most of them chondrosarcomas. The rest of the tumors was metastatic tumors in two cases and localized malignant pleural mesothelioma and non-Hodgkin lymphoma in one case. The chest wall defect was reconstructed by using the “sandwich technique” (propylene mesh/methyl methacrylate/propylene mesh) in nine cases of large anterior defects or by using a 2 mm polytetrafluoroethylene (e-PTFE) mesh in nine cases of lateral or posterior defects. Support from a plastic surgeon was necessary to cover the full-thickness chest wall defects in seven cases. Adjuvant oncologic treatment was administered in 13 patients. Local recurrences were observed in five cases where surgical reintervention was finally necessary in two cases. Recurrences were associated with larger tumors, histology of malignant fibrous histiocytoma, and initial incomplete resection or misdiagnosis made by nonthoracic surgeons. Three patients died

  15. Effect of the chest wall on breast lesion reconstruction

    NASA Astrophysics Data System (ADS)

    Ardeshirpour, Yasaman; Huang, Minming; Zhu, Quing

    2009-07-01

    The chest wall underneath the breast tissue affects near-infrared (NIR) diffusive waves measured with reflection geometry. With the assistance of a co-registered ultrasound, the depth and the tilting angle of the chest wall can be determined and are used to model the breast as a two-layer medium. Finite element method (FEM) is suitable for modeling complex boundary conditions and is adapted to model the breast tissue and chest wall. Four parameters of bulk absorption and reduced scattering coefficients of these two layers are estimated and used for imaging reconstruction. Using a two-layer model, we have systematically investigated the effect of the chest wall on breast lesion reconstruction. Results have shown that chest-wall depth, titling angle, and difference between optical properties of two layers of lesion and reference sites affect the lesion reconstruction differently. Our analysis will be valuable and informative to researchers who are using reflectance geometry for breast imaging. The analysis can also provide guidelines for imaging operators to minimize image artifacts and to produce the best reconstruction results.

  16. Ventilation distribution and chest wall mechanics in microgravity

    NASA Technical Reports Server (NTRS)

    Paiva, M.; Wantier, M.; Verbanck, S.; Engel, L. A.; Prisk, G. K.; Guy, H. J. B.; West, J. B.

    1997-01-01

    The effect of gravity on lung ventilation distribution and the mechanisms of the chest wall were investigated. The following tests were performed with the respiratory monitoring system of the Anthorack, flown onboard Spacelab D2 mission: single breath washout (SBW), multiple breath washout (MBW) and argon rebreathing (ARB). In order to study chest wall mechanisms in microgravity, a respiratory inductive plethysmograph was used. The SBW tests did not reach statistical significance, while the ARB tests showed that gravity independent inhomogeneity of specific ventilation is larger than gravity dependent inhomogeneity. In which concerns the chest wall mechanisms, the analysis on the four astronauts during the normal respirations of the relaxation maneuver showed a 40 percent increase on the abdominal contribution to respiration.

  17. Stabilization of the Chest Wall: Autologous and Alloplastic Reconstructions

    PubMed Central

    Mahabir, Raman Chaos; Butler, Charles E.

    2011-01-01

    The goals of chest wall stabilization include maintenance of a rigid airtight cavity, protection of the thoracic and abdominal contents, optimization of respiration, and, whenever possible, an aesthetic reconstruction. Evidence suggests that bony fixation results in reduced ventilator dependence, a shorter overall hospital stay, and improved upper extremity function. We prefer to accomplish this with autologous tissue alone (such as the pectoralis major, latissimus dorsi, or rectus abdominus muscle flaps) for small to moderate defects. En bloc resection of defects larger than 5 cm or containing four or more ribs will likely benefit from chest wall stabilization. For patients previously treated with radiation, even larger defects may be tolerated owing to fibrosis. For these larger defects, methyl methacrylate composite meshes are used and covered with vascularized tissue. Contaminated wounds are generally reconstructed with bioprosthetic mesh rather than synthetic mesh. Using these principles, the reconstructive plastic surgeon can devise a comprehensive and safe plan to repair tremendous defects of the chest wall. PMID:22294941

  18. Epithelioid hemangioendothelioma originating from the chest wall with rib metastases.

    PubMed

    Shimamura, Junichi; Kiyoshima, Moriyuki; Suzuki, Hisashi; Kitahara, Miyuki; Asato, Yuji; Iijima, Tatsuo; Amemiya, Ryuta

    2015-11-01

    An asymptomatic 39-year-old woman was referred to us for an abnormal nodular opacity detected on the chest X-ray. Histopathological and further examinations revealed findings consistent with epithelioid hemangioendothelioma (EHE) originating from the chest wall with metastases to the ribs. Complete excision was performed; however, adjuvant chemotherapy was not administered because of the patient's mental disorder. There are very few reports of EHE arising from the chest wall; therefore, we present this case report with the clinicopathological features of EHE and discuss the therapeutic aspects. PMID:24399489

  19. Chest wall reconstruction. Experience with 100 consecutive patients.

    PubMed Central

    Arnold, P G; Pairolero, P C

    1984-01-01

    Experience with 100 consecutive chest wall reconstructions during the past 7 years was reviewed. There were 52 female and 48 male patients with ages ranging from 13 to 78 years (average 53). Of the 100 patients, 42 had tumors of the chest wall, 19 had radiation necrosis, 24 had infected median sternotomies , and 15 had combinations of the three. Seventy-six patients underwent skeletal resection of the chest wall. An average of 5.7 ribs were resected in 63 patients. Total or partial sternectomies were performed in 29. Ninety-two patients underwent 142 muscle flaps: 77 pectoralis major, 29 latissimus dorsi, and 36 other muscles, including serratus anterior, rectus abdominis, and external oblique muscles. The omentum was transposed in ten patients. Chest wall skeletal defects were closed with Prolene mesh in 29 patients and with autogenous ribs in 11. Eighty-nine patients underwent primary closure of the skin. The 100 patients underwent an average of 2.1 operations. Hospitalization averaged 17.5 days. There was one perioperative death (29 days). Two patients required tracheostomy. Follow-up averaged 21.6 months. There were 24 late deaths. All 99 patients who were alive 30 days after operation had excellent results at the time of death or last follow-up. Images Figs. 2A-D. Figs. 3A-F. Figs. 4A-D. Figs. 4A-D. Fig. 5. Fig. 5. PMID:6732314

  20. Mechanically induced sudden death in chest wall impact (commotio cordis).

    PubMed

    Link, Mark S

    2003-01-01

    Sudden death due to nonpenetrating chest wall impact in the absence of injury to the ribs, sternum and heart is known as commotio cordis. Although once thought rare, an increasing number of these events have been reported. Indeed, a significant percentage of deaths on the athletic field are due to chest wall impact. Commotio cordis is most frequently observed in young individuals (age 4-18 years), but may also occur in adults. Sudden death is instantaneous or preceded by several seconds of lightheadedness after the chest wall blow. Victims are most often found in ventricular fibrillation, and successful resuscitation is more difficult than expected given the young age, excellent health of the victims, and the absence of structural heart disease. Autopsy examination is notable for the lack of any significant cardiac or thoracic abnormalities. In an experimental model of commotio cordis utilizing anesthetized juvenile swine, ventricular fibrillation can be produced by a 30 mph baseball strike if the strike occurred during the vulnerable period of repolarization, on the upslope of the T-wave. Energy of the impact object was also found to be a critical variable with 40 mph baseballs more likely to cause ventricular fibrillation than velocities less or greater than 40 mph. In addition, more rigid impact objects and blows directly over the center of the chest were more likely to cause ventricular fibrillation. Peak left ventricular pressure generated by the chest wall blow correlated with the risk of ventricular fibrillation. Activation of the K(+)(ATP) channel is a likely cause of the ventricular fibrillation produced by chest wall blows. Successful resuscitation is attainable with early defibrillation. PMID:12732277

  1. Electron arc therapy: chest wall irradiation of breast cancer patients.

    PubMed

    McNeely, L K; Jacobson, G M; Leavitt, D D; Stewart, J R

    1988-06-01

    From 1980 to October 1985 we treated 45 breast cancer patients with electron arc therapy. This technique was used in situations where optimal treatment with fixed photon or electron beams was technically difficult: long scars, recurrent tumor extending across midline or to the posterior thorax, or marked variation in depth of target tissue. Forty-four patients were treated following mastectomy: 35 electively because of high risk of local failure, and 9 following local recurrence. One patient with advanced local regional disease was treated primarily. The target volume boundaries on the chest wall were defined by a foam lined cerrobend cast which rested on the patient during treatment, functioning as a tertiary collimator. A variable width secondary collimator was used to account for changes in the radius of the thorax from superior to inferior border. All patients had computerized tomography performed to determine Internal Mammary Chain depth and chest wall thickness. Electron energies were selected based on these thicknesses and often variable energies over different segments of the arc were used. The chest wall and regional node areas were irradiated to 45 Gy-50 Gy in 5-6 weeks by this technique. The supraclavicular and upper axillary nodes were treated by a direct anterior photon field abutted to the superior edge of the electron arc field. Follow-up is from 10-73 months with a median of 50 months. No major complications were observed. Acute and late effects and local control are comparable to standard chest wall irradiation. The disadvantages of this technique are that the preparation of the tertiary field defining cast and CT treatment planning are labor intensive and expensive. The advantage is that for specific clinical situations large areas of chest wall with marked topographical variation can be optimally, homogeneously irradiated while sparing normal uninvolved tissues. PMID:3384727

  2. Electron arc therapy: chest wall irradiation of breast cancer patients

    SciTech Connect

    McNeely, L.K.; Jacobson, G.M.; Leavitt, D.D.; Stewart, J.R.

    1988-06-01

    From 1980 to October 1985 we treated 45 breast cancer patients with electron arc therapy. This technique was used in situations where optimal treatment with fixed photon or electron beams was technically difficult: long scars, recurrent tumor extending across midline or to the posterior thorax, or marked variation in depth of target tissue. Forty-four patients were treated following mastectomy: 35 electively because of high risk of local failure, and 9 following local recurrence. One patient with advanced local regional disease was treated primarily. The target volume boundaries on the chest wall were defined by a foam lined cerrobend cast which rested on the patient during treatment, functioning as a tertiary collimator. A variable width secondary collimator was used to account for changes in the radius of the thorax from superior to inferior border. All patients had computerized tomography performed to determine Internal Mammary Chain depth and chest wall thickness. Electron energies were selected based on these thicknesses and often variable energies over different segments of the arc were used. The chest wall and regional node areas were irradiated to 45 Gy-50 Gy in 5-6 weeks by this technique. The supraclavicular and upper axillary nodes were treated by a direct anterior photon field abutted to the superior edge of the electron arc field. Follow-up is from 10-73 months with a median of 50 months. No major complications were observed. Acute and late effects and local control are comparable to standard chest wall irradiation. The disadvantages of this technique are that the preparation of the tertiary field defining cast and CT treatment planning are labor intensive and expensive. The advantage is that for specific clinical situations large areas of chest wall with marked topographical variation can be optimally, homogeneously irradiated while sparing normal uninvolved tissues.

  3. High-frequency oscillation of the airway and chest wall.

    PubMed

    Fink, James B; Mahlmeister, Michael J

    2002-07-01

    High-frequency oscillation (HFO), applied to either the airway or chest wall, has been associated with changes in sputum attributes and clearance. The evolution of evidence, both in vitro and in vivo, supporting the use of HFO is reviewed. Devices that apply HFO to the airway range from the relatively simple mechanical Flutter and Acapella devices to the more complex Percussionaire Intrapercussive Ventilators. and the Hayek Oscillator are designed to provide high-frequency chest wall compression. Operation and use of these devices are described with examples of differentiation of device types by characterization of flows, and airway and esophageal pressures. Although HFO devices span a broad range of costs, they provide a reasonable therapeutic option to support secretion clearance for patients with cystic fibrosis. PMID:12088550

  4. Chest wall reconstruction with methacrylate prosthesis in Poland syndrome.

    PubMed

    Arango Tomás, Elisabet; Baamonde Laborda, Carlos; Algar Algar, Javier; Salvatierra Velázquez, Angel

    2013-10-01

    Poland syndrome is a rare congenital malformation. This syndrome was described in 1841 by Alfred Poland at Guy's Hospital in London. It is characterized by hypoplasia of the breast and nipple, subcutaneous tissue shortages, lack of the costosternal portion of the pectoralis major muscle and associated alterations of the fingers on the same side. Corrective treatment of the chest and soft tissue abnormalities in Poland syndrome varies according to different authors. We report the case of a 17-year-old adolescent who underwent chest wall reconstruction with a methyl methacrylate prosthesis. This surgical procedure is recommended for large anterior chest wall defects, and it prevents paradoxical movement. Moreover it provides for individual remodeling of the defect depending on the shape of the patient's chest. PMID:23453291

  5. Chest wall syndrome among primary care patients: a cohort study

    PubMed Central

    Verdon, François; Burnand, Bernard; Herzig, Lilli; Junod, Michel; Pécoud, Alain; Favrat, Bernard

    2007-01-01

    Background The epidemiology of chest pain differs strongly between outpatient and emergency settings. In general practice, the most frequent cause is the chest wall pain. However, there is a lack of information about the characteristics of this syndrome. The aims of the study are to describe the clinical aspects of chest wall syndrome (CWS). Methods Prospective, observational, cohort study of patients attending 58 private practices over a five-week period from March to May 2001 with undifferentiated chest pain. During a one-year follow-up, questionnaires including detailed history and physical exam, were filled out at initial consultation, 3 and 12 months. The outcomes were: clinical characteristics associated with the CWS diagnosis and clinical evolution of the syndrome. Results Among 24 620 consultations, we observed 672 cases of chest pain and 300 (44.6%) patients had a diagnosis of chest wall syndrome. It affected all ages with a sex ratio of 1:1. History and sensibility to palpation were the keys for diagnosis. Pain was generally moderate, well localised, continuous or intermittent over a number of hours to days or weeks, and amplified by position or movement. The pain however, may be acute. Eighty-eight patients were affected at several painful sites, and 210 patients at a single site, most frequently in the midline or a left-sided site. Pain was a cause of anxiety and cardiac concern, especially when acute. CWS coexisted with coronary disease in 19 and neoplasm in 6. Outcome at one year was favourable even though CWS recurred in half of patients. Conclusion CWS is common and benign, but leads to anxiety and recurred frequently. Because the majority of chest wall pain is left-sided, the possibility of coexistence with coronary disease needs careful consideration. PMID:17850647

  6. Microvascular Reconstructions of Full-Thickness Oncological Chest Wall Defects

    PubMed Central

    Tukiainen, Erkki; Popov, Pentscho; Asko-Seljavaara, Sirpa

    2003-01-01

    Objective: To evaluate the suitability of microvascular flaps for the reconstruction of extensive full-thickness defects of the chest wall. Summary Background Data: Chest wall defects are conventionally reconstructed with pedicular musculocutaneous flaps or the omentum. Sometimes, however, these flaps have already been used, are not reliable due to previous operations or radiotherapy, or are of inadequate size. In such cases, microvascular flaps offer the only option for reconstruction. Methods: From 1988 to 2001, 26 patients with full-thickness resections of the chest wall underwent reconstruction with microvascular flaps. There were 8 soft tissue sarcomas, 8 recurrent breast cancers, 5 chondrosarcomas, 2 desmoid tumors, 1 large cell pulmonary cancer metastasis, 1 renal cancer metastasis, and 1 bronchopleural fistula. The surgery comprised 5 extended forequarter amputations, 5 lateral resections, 8 thoracoabdominal resections, and 8 sternal resections. The mean diameter of a resection was 28 cm. The soft tissue defect was reconstructed with 16 tensor fasciae latae, 5 tensor fascia latae combined with rectus femoris, and 3 transversus rectus abdominis myocutaneous flaps. In 2 patients with a forequarter amputation, the remnant forearm was used as the osteomusculocutaneous free flap. Results: There were no flap losses or perioperative mortality. Four patients needed tracheostomy owing to prolonged respiratory difficulties. The mean survival time for patients with sarcomas was 39 months and for those with recurrent breast cancer 18 months. Conclusions: Extensive chest wall resections are possible with acceptable results. In patients with breast cancer, the surgery may offer valuable palliation and in those with sarcomas it can be curative. PMID:14631216

  7. A magnetostrictive acceleration sensor for registration of chest wall displacements

    NASA Astrophysics Data System (ADS)

    Kaniusas, E.; Mehnen, L.; Krell, C.; Pfützner, H.

    2000-06-01

    The present study concerns a novel acceleration sensor built up using a bimetallic strip with one freely oscillating end. The strip consists of a magnetostrictive amorphous ribbon glued on a nonmagnetic metal ribbon. The sensor's effectiveness is demonstrated for the case of chest wall displacements as resulting from cardiorespiratory activity. The cheap and easy-to-handle novel sensor offers multiple information on the so-called sleep apnea syndrome.

  8. Radiation-induced sarcomas of the chest wall

    SciTech Connect

    Souba, W.W.; McKenna, R.J. Jr.; Meis, J.; Benjamin, R.; Raymond, A.K.; Mountain, C.F.

    1986-02-01

    Sixteen patients are presented who had sarcomas of the chest wall at a site where a prior malignancy had been irradiated. The first malignancies included breast cancer (ten cases), Hodgkin's disease (four cases), and others (two cases). Radiation doses varied from 4200 to 5500 R (mean, 4900 R). The latency period ranged from 5 to 28 years (mean, 13 years). The histologic types of the radiation-induced sarcomas were as follows: malignant fibrous histiocytoma, nine cases; osteosarcoma, six cases; and malignant mesenchymoma, one case. The only long-term survivor is alive and well 12 years after resection of a clavicular chondroblastic osteosarcoma. Three cases were recently diagnosed. Despite aggressive multimodality treatment, the remaining 13 patients have all died from their sarcomas (mean survival, 13.5 months). All patients have apparently been cured of their first malignancies. Chemotherapy was ineffective. No treatment, including forequarter amputation, appeared to palliate the patients with supraclavicular soft tissue sarcomas. Major chest wall resection offered good palliation for seven of eight patients with sarcomas arising in the sternum or lateral chest wall. Close follow-up is needed to detect signs of these sarcomas in the ever-increasing number of patients receiving therapeutic irradiation.

  9. Tracheal mucus clearance in high-frequency oscillation. II: Chest wall versus mouth oscillation.

    PubMed

    King, M; Phillips, D M; Zidulka, A; Chang, H K

    1984-11-01

    We compared the tracheal mucus clearance rate (TMCR) in anesthetized dogs during spontaneous breathing (SB), ventilation by high-frequency oscillation at the airway opening (HFO/AO), and ventilation by high-frequency oscillation of the chest wall (HFO/CW). The HFO/AO was carried out by using a piston pump with a high impedance transverse flow at the proximal end of the endotracheal tube; HFO/CW was effected by creating rapid pressure oscillations in an air-filled cuff wrapped around the lower thorax of the animal, causing small tidal volumes at the mouth. The TMCR was measured by observing the rate of displacement of a charcoal marker in the lower trachea; a fiberoptic bronchoscope was used to deposit the marker before each experiment and to relocate it after a 5-min run. In 7 dogs, mean TMCR during control (SB) was 8.9 +/- 3.5 mm/min. At 13 Hz with an oscillatory tidal volume (VTO) of 1.5 ml/kg, mean TMCR was 240% of control with HFO/CW (p less than 0.001) and 76% of control with HFO/AO (NS). During HFO/AO at 20 Hz and a VTO of 3 ml/kg, mean TMCR was 97% of control. We conclude that high-frequency ventilation by rapid chest wall compression enhances tracheal mucus clearance when compared with spontaneous breathing, whereas high-frequency oscillation at the mouth does not. PMID:6497152

  10. Algorithmic Error Correction of Impedance Measuring Sensors

    PubMed Central

    Starostenko, Oleg; Alarcon-Aquino, Vicente; Hernandez, Wilmar; Sergiyenko, Oleg; Tyrsa, Vira

    2009-01-01

    This paper describes novel design concepts and some advanced techniques proposed for increasing the accuracy of low cost impedance measuring devices without reduction of operational speed. The proposed structural method for algorithmic error correction and iterating correction method provide linearization of transfer functions of the measuring sensor and signal conditioning converter, which contribute the principal additive and relative measurement errors. Some measuring systems have been implemented in order to estimate in practice the performance of the proposed methods. Particularly, a measuring system for analysis of C-V, G-V characteristics has been designed and constructed. It has been tested during technological process control of charge-coupled device CCD manufacturing. The obtained results are discussed in order to define a reasonable range of applied methods, their utility, and performance. PMID:22303177

  11. Chest wall motion in preterm infants using respiratory inductive plethysmography.

    PubMed

    Warren, R H; Horan, S M; Robertson, P K

    1997-10-01

    Preterm infant tidal breathing may be different from that of healthy full-term infants because of various features of the premature thorax. The purpose of this project was to describe chest wall motion in the preterm infant (gestational age <37 weeks) and compare it with chest wall motion data in a group of healthy, full-term infants. We wanted to use an objective bedside method for assessment with minimal disruption to the infant. The study population consisted of 61 preterm human infants whose mean(+/-sD) postconceptional age at time of study was 35.3+/-2.1 weeks. During the study, the infants were quietly awake in a prone position. Preterm infants had initially been admitted to a level III neonatal intensive care unit for acute management and had been transferred to a step-down area, where they were in stable condition for study. Data were collected with a semiquantitatively calibrated, noninvasive respiratory inductive plethysmograph. Mean(+/-SD) phase angle was significantly greater in preterm infants than in full-term infants (60.6+/-39.8 degrees versus 12.5+/-5.0 degrees, respectively, p < or = 0.0001). The laboured breathing index was significantly greater in preterm infants than in full-term infants (1.35+/-0.35 versus 1.01+/-0.01, respectively, p = 0.001). The ribcage contribution to breathing did not differ significantly between preterm and full-term infants (25.5+/-17.7% versus 36.3+/-14.4%, respectively, p = 0.11). These results indicate a significant increase in the degree of ribcage and abdomen asynchrony in the preterm subjects compared to the full-term infants. Plethysmography provided a time-efficient and objective method of assessing chest wall motion in this fragile population. PMID:9387956

  12. Primary malignant chest wall tumors: analysis of 40 patients

    PubMed Central

    2014-01-01

    Background Primary chest wall tumors originate from different constructions of thoracic wall. We report our multidisciplinary experience on primary thoracic tumor resection and thoracic reconstruction, the need to additional therapy and evaluating prognostic factors affecting survival. Methods We performed a retrospective review of our prospectively maintained database of 40 patients treated for malignant primary chest wall tumor from 1989 to 2009. Patients were evaluated in terms of age, sex, clinical presentation, type of imaging, tissue diagnosis methods, pathology, surgical technique, early complications, hospital mortality, prevalence of recurrence and distant metastases, additional treatment, 3 years survival and factors affecting survival. Results Male/Female (F/M) = 1, with median age of 43.72 years. Mass was the most common symptoms and the soft tissue sarcoma was the most common pathology. Resection without reconstruction was performed in 5 patients and Thirty-five patients (87.5%) had extensive resection and reconstruction with rotatory muscular flap, prosthetic mesh and/or cement. Overall, 12.5% (5/40) of patients received neoadjuvant therapy and 75% (30/40) of patients were treated with adjuvant therapy. The 3-year survival rate was 65%. Recurrences occurred in 24 patients (60%), 14 developed local recurrences, and 10 developed distant metastases. The primary treatment modality for both local and distant recurrences was surgical resection; among them, 10 underwent repeated resection, 9 adjuvant therapy and 5 were treated with lung metastasectomy. The most common site of distant metastasis was lung (n = 7). Factors that affected survival were type of pathology and evidence of distant metastasis. Conclusion Surgery with wide margin is the safe and good technique for treatment of primary chest wall tumors with acceptable morbidity and mortality. PMID:24947314

  13. Using "Rebar" to Stabilize Rigid Chest Wall Reconstruction.

    PubMed

    Robinson, Lary A; Grubbs, Deanna M

    2016-04-01

    After major chest wall resection, reconstruction of the bony defect with a rigid prosthesis is mandatory to protect the underlying thoracic organs, and to prevent flail chest physiology. Although many methods have been described for chest wall reconstruction, a commonly used technique employs a composite Marlex (polypropylene) mesh with methyl-methacrylate cement sandwiched between two layers of mesh (MMS), which is tailored to the defect size and shape. In building construction, steel "rebar" is used to strengthen and reinforce masonry structures. To avoid the initial residual motion of the rigid prosthesis used to reconstruct very large defects, particularly the sternum, we devised a simple technique of adding one or more Steinmann steel pins as "rebar" to strengthen and immediately stabilize the prosthesis to the surrounding ribs and sternum. For the very large defects, particularly over the heart and great vessels, titanium mesh may also be readily added into the sandwich construction for increased strength and to prevent late prosthetic fractures. Short- and long-term results of this inexpensive modification of the MMS reconstruction technique are excellent. This modified MMS tailor-made prosthesis is only one-third the cost of the recently popular prosthetic titanium systems, takes much less operative time to create and implant, and avoids the well-described complications of late titanium bar fracture and erosion/infection as well as loosening of screws and/or titanium bars. PMID:25602843

  14. Predicting Chest Wall Pain From Lung Stereotactic Body Radiotherapy for Different Fractionation Schemes

    SciTech Connect

    Woody, Neil M.; Videtic, Gregory M.M.; Stephans, Kevin L.; Djemil, Toufik; Kim, Yongbok; Xia Ping

    2012-05-01

    Purpose: Recent studies with two fractionation schemes predicted that the volume of chest wall receiving >30 Gy (V30) correlated with chest wall pain after stereotactic body radiation therapy (SBRT) to the lung. This study developed a predictive model of chest wall pain incorporating radiobiologic effects, using clinical data from four distinct SBRT fractionation schemes. Methods and Materials: 102 SBRT patients were treated with four different fractionations: 60 Gy in three fractions, 50 Gy in five fractions, 48 Gy in four fractions, and 50 Gy in 10 fractions. To account for radiobiologic effects, a modified equivalent uniform dose (mEUD) model calculated the dose to the chest wall with volume weighting. For comparison, V30 and maximum point dose were also reported. Using univariable logistic regression, the association of radiation dose and clinical variables with chest wall pain was assessed by uncertainty coefficient (U) and C statistic (C) of receiver operator curve. The significant associations from the univariable model were verified with a multivariable model. Results: 106 lesions in 102 patients with a mean age of 72 were included, with a mean of 25.5 (range, 12-55) months of follow-up. Twenty patients reported chest wall pain at a mean time of 8.1 (95% confidence interval, 6.3-9.8) months after treatment. The mEUD models, V30, and maximum point dose were significant predictors of chest wall pain (p < 0.0005). mEUD improved prediction of chest wall pain compared with V30 (C = 0.79 vs. 0.77 and U = 0.16 vs. 0.11). The mEUD with moderate weighting (a = 5) better predicted chest wall pain than did mEUD without weighting (a = 1) (C = 0.79 vs. 0.77 and U = 0.16 vs. 0.14). Body mass index (BMI) was significantly associated with chest wall pain (p = 0.008). On multivariable analysis, mEUD and BMI remained significant predictors of chest wall pain (p = 0.0003 and 0.03, respectively). Conclusion: mEUD with moderate weighting better predicted chest wall pain than

  15. CT after reconstructive repair of the sternum and chest wall.

    PubMed

    Maddern, I R; Goodman, L R; Almassi, G H; Haasler, G B; McManus, R P; Olinger, G N

    1993-03-01

    Acute mediastinitis and sternal infection after sternotomy are potentially devastating complications, but considerable advances in treatment have been made during the past decade. Sternectomy followed by reconstruction with use of either an omental transposition or a muscle flap has markedly decreased mortality and morbidity. After extensive rib resection, various reconstructive repairs, including the use of polytetrafluoroethylene mesh, have proved successful. The authors retrospectively reviewed 27 postoperative computed tomographic (CT) scans obtained in 19 patients. Twelve of these patients had sternal wounds repaired with either omental or muscle flap procedures. Seven patients had chest wall reconstructions with polytetrafluoroethylene patches, muscle transpositions, or both. The authors found no cases of unexpected or unexplained fluid collections on CT scans obtained beyond the 1st month. Any persistent or recurrent collection is suggestive of infection. If clinical and imaging findings are at odds, imaging-directed needle aspiration can help determine whether a fluid collection is infected and in need of further treatment. PMID:8430171

  16. Chest wall reconstruction using iliac bone allografts and muscle flaps.

    PubMed

    Garcia-Tutor, Emilio; Yeste, Luis; Murillo, Julio; Aubá, Cristina; Sanjulian, Mikel; Torre, Wenceslao

    2004-01-01

    Technically we can divide full-thickness thoracic reconstruction into 2 parts: providing a rigid support and ensuring well-vascularized coverage. Since 1986, the authors' center has had ample experience with bone banks and the use of cryopreserved bone grafts, which led them to consider the possibility of using these grafts for full-thickness chest wall reconstruction. They describe 3 patients in whom resection of the tumor and reconstruction of the thorax were carried out using iliac bone allografts covered with muscle flaps (1 pectoralis major and 2 rectus abdominis). None of the patients experienced breathing difficulties, pain, or instability after 14 months, 18 months, and 11 years of follow-up. The result of the reconstruction was excellent in all 3 patients in terms of function and aesthetics. The advantage of allografts compared with synthetic materials is their potential integration; they can become part of the host patient's living tissue. PMID:14676700

  17. Clinical image: Hydatid disease of the chest wall

    SciTech Connect

    Graham, R.J.; Berlin, J.W.; Ghahremani, G.G.

    1996-05-01

    Hydatid disease is rarely encountered among the population of the United States, but it affects several million people in sheep-raising regions of the world. Human infestation with Echinococcus granulosus begins following ingestion of its ova, which are excreted into the contaminated water during the usual dog-sheep cycle. Hydatid cysts will then develop most frequently in the liver (75% of cases) and lungs (15%) of the human host. Skeletal involvement has been reported to occur in only 0.5-4.0% of patients in the endemic areas. Because of the rarity and perplexing imaging features of hydatid disease involving the chest wall, we wish herein to present a case evaluated recently at our institution. 5 refs., 1 fig.

  18. RLC model of visco-elastic properties of the chest wall

    NASA Astrophysics Data System (ADS)

    Aliverti, Andrea; Ferrigno, Giancarlo

    1996-04-01

    The quantification of the visco-elastic properties (resistance (R), inertia (L) and compliance (C)) of the different chest wall compartments (pulmonary rib cage,diaphragmatic rib cage and abdomen) is important to study the status of the passive components of the respiratory system, particularly in selected pathologies. Applying the viscoelastic-electrical analogy to the chest wall, we used an identification method in order to estimate the R, L and C parameters of the different parts of the chest, basing on different models; the input and output measured data were constituted by the volume variations of the different chest wall compartments and by the nasal pressure during controlled intermittent positive pressure ventilation by nasal mask, while the parameters of the system (R, L and C of the different compartments) were to be estimated. Volumes were measured with a new method, recently validated, based on an opto-electronic motion analyzer, able to compute with high accuracy and null invasivity the absolute values and the time variations of the volumes of each of the three compartments. The estimation of the R, L and C parameters has been based on a least-squared criterion, and the minimization has been based on a robustified iterative Gauss-Newton algorithm. The validation of the estimation procedure (fitting) has ben performed computing the percentage root mean square value of the error between the output real data and the output estimated data. The method has been applied to 2 healthy subjects. Also preliminary results have been obtained from 20 subjects affected by neuromuscular diseases (Duchenne Muscular Dystrophy (DMD) and Spinal Muscle Atrophy (SMA)). The results show that: (a) the best-fitting electrical models of the respiratory system are made up by one or three parallel RLC branches supplied by a voltage generator (so considering inertial properties, particularly in the abdominal compartment, and not considering patient/machine connection); (b) there

  19. Chest Wall Motion during Speech Production in Patients with Advanced Ankylosing Spondylitis

    ERIC Educational Resources Information Center

    Kalliakosta, Georgia; Mandros, Charalampos; Tzelepis, George E.

    2007-01-01

    Purpose: To test the hypothesis that ankylosing spondylitis (AS) alters the pattern of chest wall motion during speech production. Method: The pattern of chest wall motion during speech was measured with respiratory inductive plethysmography in 6 participants with advanced AS (5 men, 1 woman, age 45 plus or minus 8 years, Schober test 1.45 plus or…

  20. The development of algorithms in electrical impedance computerized tomography.

    PubMed

    Shie, J R; Li, C J; Lin, J T

    2000-01-01

    Electrical Impedance Computerized Tomography (EICT) is an imaging method to reconstruct the impedance distribution inside of domain through the boundary injected current and display the impedance contrast ratio as an image. This paper concentrates on developing two algorithms to enhance the quality of the conductivity image. The two algorithms are "Fine-Mesh Conversion Method" and "Sub-Domain EICT Method". "Fine-Mesh Conversion Method" is a numerical calibration process to find a coarse mesh impedance network that behaves like a fine mesh network in terms of giving similar voltages under the same current excitations. "Sub-Domain EICT" solves a higher resolution EICT with the cost of a lower resolution EICT by combining "Fine-Mesh Conversion Method", and a Fuzzy Logic Inference Systems (FLIS) classifier. PMID:10834231

  1. A triceps musculocutaneous flap for chest-wall defects

    SciTech Connect

    Hartrampf, C.R. Jr.; Elliott, L.F.; Feldman, S. )

    1990-09-01

    A posterior upper arm flap based on the profunda brachii vessels has been described to cover soft-tissue defects in the upper anterolateral chest. In our series, the posterior upper arm skin is elevated with the long head of the triceps muscle to cover seven chest-wall defects resulting from indolent postradiation open wounds following partial TRAM flap failure (n = 2), soft-tissue deficiencies following partial TRAM flap loss (n = 3), and primarily as an ancillary flap in TRAM flap breast reconstruction (n = 2). This flap also may be used to supply well-vascularized tissue in the regions of the shoulder, axilla, and posterolateral back. A prerequisite for this operation is redundant tissue of the upper arm often present in middle-aged women and in patients with lymphedema following mastectomy. In our series of seven patients, all donor sites were closed primarily, and there was no subjective functional deficit following transfer of the long head of the triceps muscle.

  2. Reconstruction with a patient-specific titanium implant after a wide anterior chest wall resection

    PubMed Central

    Turna, Akif; Kavakli, Kuthan; Sapmaz, Ersin; Arslan, Hakan; Caylak, Hasan; Gokce, Hasan Suat; Demirkaya, Ahmet

    2014-01-01

    The reconstruction of full-thickness chest wall defects is a challenging problem for thoracic surgeons, particularly after a wide resection of the chest wall that includes the sternum. The location and the size of the defect play a major role when selecting the method of reconstruction, while acceptable cosmetic and functional results remain the primary goal. Improvements in preoperative imaging techniques and reconstruction materials have an important role when planning and performing a wide chest wall resection with a low morbidity rate. In this report, we describe the reconstruction of a wide anterior chest wall defect with a patient-specific custom-made titanium implant. An infected mammary tumour recurrence in a 62-year old female, located at the anterior chest wall including the sternum, was resected, followed by a large custom-made titanium implant. Latissimus dorsi flap and split-thickness graft were also used for covering the implant successfully. A titanium custom-made chest wall implant could be a viable alternative for patients who had large chest wall tumours. PMID:24227881

  3. A single plan solution to chest wall radiotherapy with bolus?

    PubMed Central

    Ordonez-Sanz, C; Bowles, S; Hirst, A

    2014-01-01

    Objective: Radiotherapy treatments of post-mastectomy chest walls are complex, requiring treatment close to skin, necessitating bolus use. Commonly used 5- and 10-mm-thick boluses develop full skin dose, needing removal for the latter half of treatment and requiring two treatment plans to be generated. Can a thinner bolus be used for all treatment fractions, requiring only one plan? Methods: Investigation of doses received using (A) a half-time 10-mm-thick Vaseline® bolus (current situation); (B) a brass mesh (Whiting & Davis, Attleboro Falls, MA) and (C) 3- and 5-mm Superflab™ (Mick Radio-Nuclear Instruments, Mount Vernon, NY) for 6 and 15 MV. Dosimetric measurements in Barts WT1 solid water and an anthropomorphic phantom, using ionization chambers and thermoluminescent dosemeters, were used to study the effect of different bolus regimes on the photon depth–dose curves (DDCs) and skin doses. Results: Measured skin doses for the current 10-mm-thick Vaseline bolus, brass mesh and 3-mm bolus were compared (5 mm bolus has been rejected). The brass mesh has the least effect on the DDC, with changes <0.7% for depths greater than dmax. Brass mesh conforms superiorly to skin surfaces. Measurements on an anthropomorphic phantom demonstrate an increased skin dose compared with our current treatment protocol. Conclusion: Brass mesh has the smallest effect on the DDC, whilst sufficiently increasing surface dose. It can be removed at any fraction, based on a clinical decision, without the need for generating a new plan. Treating with one plan significantly reduces planning times. Advances in knowledge: Quantification of skin doses required and achieved from wax-on/wax-off treatment compared with alternative available breast boluses. PMID:24646288

  4. CONSTANT-PHASE DESCRIPTIONS OF CANINE LUNG, CHEST WALL, AND TOTAL RESPIRATORY SYSTEM VISCOELASTICITY: EFFECTS OF DISTENDING PRESSURE

    PubMed Central

    Kaczka, David W.; Smallwood, Jennifer L.

    2012-01-01

    The dynamic mechanical properties of the respiratory system reflect the ensemble behavior of its constituent structural elements. This study assessed the appropriateness of constant-phase descriptions of respiratory tissue viscoelasticity at various distending pressures. We measured the mechanical input impedance (Z) of the lungs, chest wall and total respiratory system in twelve dogs at mean airway pressures from 5 to 30 cmH2O. Each Z was fitted with a constant-phase model which provided estimates tissue damping (G), elastance (H), and hysteresivity (η = G/H). Both G and H sharply increased with increasing distending pressure for the lungs and chest wall, while η attained a minimum near 15-20 cm H2O. Model fitting errors for the lungs and total respiratory system increased for distending pressures greater than 20 cm H2O, indicating that constant-phase descriptions of parenchymal and respiratory system viscoelasticty may be inappropriate at volumes closer to total lung capacity. Such behavior may reflect alterations in load distribution across various parenchymal stress-bearing elements. PMID:22691447

  5. Arena Roof Technique for Complex Reconstruction After Extensive Chest Wall Resection.

    PubMed

    Rocco, Gaetano; La Rocca, Antonello; La Manna, Carmine; Martucci, Nicola; De Luca, Giuseppe; Accardo, Rosanna

    2015-10-01

    Extensive primary resections or redos may produce significant chest wall defects requiring creative reconstructions in order to avoid reduction of the intrathoracic volume. We describe the successful use of an innovative technique for chest wall reconstruction based on the concept of roof coverage of sport arenas. In fact, titanium plates are anchored to the residual rib stumps along the parasternal and paravertebral lines. The acellular collagen matrix prosthesis was sutured to the free edges of the same titanium plates to create a roof, reproducing the chest wall dome geometric configuration. A 36-year-old female patient was diagnosed with an extensive desmoid tumor involving the lateral segments of second to fifth ribs on the right side. The arena roof technique allowed for adequate expansion of the uninvolved lung and optimal chest wall functional recovery. PMID:26434458

  6. Prediction of Chest Wall Toxicity From Lung Stereotactic Body Radiotherapy (SBRT)

    SciTech Connect

    Stephans, Kevin L.; Djemil, Toufik; Tendulkar, Rahul D.; Robinson, Cliff G.; Reddy, Chandana A.; Videtic, Gregory M.M.

    2012-02-01

    Purpose: To determine patient, tumor, and treatment factors related to the development of late chest wall toxicity after lung stereotactic body radiotherapy (SBRT). Methods and Materials: We reviewed a registry of 134 patients treated with lung SBRT to 60 Gy in 3 fractions who had greater than 1 year of clinical follow-up and no history of multiple treatments to the same lobe (n = 48). Patients were treated as per Radiation Therapy Oncology Group Protocol 0236 without specific chest wall avoidance criteria. The chest wall was retrospectively contoured. Thirty-two lesions measured less than 3 cm, and sixteen measured 3 to 5 cm. The median planning target volume was 29 cm{sup 3}. Results: With a median follow-up of 18.8 months, 10 patients had late symptomatic chest wall toxicity (4 Grade 1 and 6 Grade 2) at a median of 8.8 months after SBRT. No patient characteristics (age, diabetes, hypertension, peripheral vascular disease, or body mass index) were predictive for toxicity, whereas there was a trend for continued smoking (p = 0.066; odds ratio [OR], 4.4). Greatest single tumor dimension (p = 0.047; OR, 2.63) and planning target volume (p = 0.040; OR, 1.04) were correlated with toxicity, whereas distance from tumor edge to chest wall and gross tumor volume did not reach statistical significance. Volumes of chest wall receiving 30 Gy (V30) through 70 Gy (V70) were all highly significant, although this correlation weakened for V65 and V70 and maximum chest wall point dose only trended to significance (p = 0.06). On multivariate analysis, tumor volume was no longer correlated with toxicity and only V30 through V60 remained statistically significant. Conclusions: Tumor size and chest wall dosimetry are correlated to late chest wall toxicity. Only chest wall V30 through V60 remained significant on multivariate analysis. Restricting V30 to 30 cm{sup 3} or less and V60 to 3 cm{sup 3} or less should result in a 10% to 15% risk of late chest wall toxicity or lower.

  7. Extrathoracic chronic heamatoma presenting as a chest wall tumor 2 years after a blunt thoracic injury.

    PubMed

    Kouritas, Vasileios K; Roussakis, Antonios G; Soultanis, Konstantinos; Bellenis, Ion

    2011-01-01

    Chronic expanding heamatomas may present as masses mimicking chest wall tumors. We report the case of a patient who was presented with a giant posterior extrathoracic chest wall tumor. The mass was proven to be a chronic heamatoma possibly developed after a blunt thoracic injury which took place 2 years before presentation and was growing thereafter. Clinicians should have high suspicion of rare entities which mimic tumors and consider any information reported by the patient's history in their diagnostic process. PMID:22112630

  8. Extrathoracic chronic heamatoma presenting as a chest wall tumor 2 years after a blunt thoracic injury

    PubMed Central

    2011-01-01

    Chronic expanding heamatomas may present as masses mimicking chest wall tumors. We report the case of a patient who was presented with a giant posterior extrathoracic chest wall tumor. The mass was proven to be a chronic heamatoma possibly developed after a blunt thoracic injury which took place 2 years before presentation and was growing thereafter. Clinicians should have high suspicion of rare entities which mimic tumors and consider any information reported by the patient's history in their diagnostic process. PMID:22112630

  9. Obesity Increases the Risk of Chest Wall Pain From Thoracic Stereotactic Body Radiation Therapy

    SciTech Connect

    Welsh, James; Thomas, Jimmy; Shah, Deep; Allen, Pamela K.; Wei, Xiong; Mitchell, Kevin; Gao, Song; Balter, Peter; Komaki, Ritsuko; Chang, Joe Y.

    2011-09-01

    Purpose: Stereotactic body radiation therapy (SBRT) is increasingly being used to treat thoracic tumors. We attempted here to identify dose-volume parameters that predict chest wall toxicity (pain and skin reactions) in patients receiving thoracic SBRT. Patients and Methods: We screened a database of patients treated with SBRT between August 2004 and August 2008 to find patients with pulmonary tumors within 2.5 cm of the chest wall. All patients received a total dose of 50 Gy in four daily 12.5-Gy fractions. Toxicity was scored according to the NCI-CTCAE V3.0. Results: Of 360 patients in the database, 265 (268 tumors) had tumors within <2.5 cm of the chest wall; 104 (39%) developed skin toxicity (any grade); 14 (5%) developed acute pain (any grade), and 45 (17%) developed chronic pain (Grade 1 in 22 cases [49%] and Grade 2 or 3 in 23 cases [51%]). Both skin toxicity and chest wall pain were associated with the V{sub 30}, or volume of the chest wall receiving 30 Gy. Body mass index (BMI) was also strongly associated with the development of chest pain: patients with BMI {>=}29 had almost twice the risk of chronic pain (p = 0.03). Among patients with BMI >29, diabetes mellitus was a significant contributing factor to the development of chest pain. Conclusion: Safe use of SBRT with 50 Gy in four fractions for lesions close to the chest wall requires consideration of the chest wall volume receiving 30 Gy and the patient's BMI and diabetic state.

  10. Assessment of the chest wall thickness of the lawrence livermore torso phantom using a voxel image.

    PubMed

    Ahmed, A S M Sabbir; Capello, Kevin; Kramer, Gary H

    2011-06-01

    This paper describes the methodology of measuring the chest wall thickness using the voxel image of the Lawrence Livermore National Lab (LLNL) torso phantom. The LLNL phantom is used as a standard to calibrate a lung counter consisting of a 2 × 2 array of germanium detectors. In general, an average thickness estimated from four counting positions is used as the chest wall thickness for a given overlay plate. For a given overlay, the outer chest surface differs from that of inner one, and the chest wall thickness varies from one position to other. The LLNL phantom with chest plate and C4 overlay plate installed was scanned with a CT (computed tomography) scanner. The image data, collected in DICOM (Digital Imaging and Communication) format, were converted to the MCNP input file by using the Scan2Mcnp program. The MCNP file was visualized and analyzed with the Moritz visual editor. An analytic expression was formulated and solved to calculate the chest wall thickness by using the point detector responses (F 5 tally of MCNP). To map the chest thickness, the entire chest wall was meshed into virtual grids of 1 cm width. A source and detector pair was moved along the inner and outer surface of the chest wall from right to left at different heights from neck to abdomen. For each height (z(k)), (x(i), y(j)) coordinates for the detector source pair were calculated from the visual editor and were scaled on-screen. For each (x(i), y(j), z(k)) position, a mesh thickness was measured from on-screen measurement and by solving the detector responses. The chest wall thicknesses at different positions on the outer surface of the chest were compared and verified using two methods. PMID:22004927

  11. Dose-Response Model for Chest Wall Tolerance of Stereotactic Body Radiation Therapy.

    PubMed

    Kimsey, Frank; McKay, Jesse; Gefter, Jeffrey; Milano, Michael T; Moiseenko, Vitali; Grimm, Jimm; Berg, Ronald

    2016-04-01

    Many recent studies have described rib fractures and chest wall pain following stereotactic body radiation therapy (SBRT). Although these toxicities generally are not life-threatening, the chest wall and ribs are considered dose-limiting tissues because of the potential effect on patients׳ quality of life. Few studies have reported dose-response models that can provide quantitative estimates of risk as a function of dose and volume. Notably, Memorial Sloan Kettering Cancer Center (Mutter et al(8)) analyzed grade 2 or higher chest wall toxicity in a cohort of 126 patients treated with linear accelerator-based SBRT; the authors provided detailed dose-volume histogram (DVH) data to allow for pooled analyses. We pooled these 126 patients with an additional 44 patients treated with CyberKnife at the Erlanger Medical Center to create an updated dose-response model for chest wall tolerance. In the aggregate analysis, the 10% risk level for grade 2 or higher complications for D70cc was 16.2Gy in 4 fractions, and the 50% risk level was D70cc = 65.1Gy in 4 fractions. For D2cc, the 10% and 50% risk levels in 4 fractions were 43.0Gy and 87.9Gy, respectively. These dose-tolerance limits may help quantify chest wall toxicity risks. Further research continues to determine more accurate estimates of grade 3 risk levels. PMID:27000509

  12. Some Nonlinear Reconstruction Algorithms for Electrical Impedance Tomography

    SciTech Connect

    Berryman, J G

    2001-03-09

    An impedance camera [Henderson and Webster, 1978; Dines and Lytle, 1981]--or what is now more commonly called electrical impedance tomography--attempts to image the electrical impedance (or just the conductivity) distribution inside a body using electrical measurements on its boundary. The method has been used successfully in both biomedical [Brown, 1983; Barber and Brown, 1986; J. C. Newell, D. G. Gisser, and D. Isaacson, 1988; Webster, 1990] and geophysical applications [Wexler, Fry, and Neurnan, 1985; Daily, Lin, and Buscheck, 1987], but the analysis of optimal reconstruction algorithms is still progressing [Murai and Kagawa, 1985; Wexler, Fry, and Neurnan, 1985; Kohn and Vogelius, 1987; Yorkey and Webster, 1987; Yorkey, Webster, and Tompkins, 1987; Berryman and Kohn, 1990; Kohn and McKenney, 1990; Santosa and Vogelius, 1990; Yorkey, 1990]. The most common application is monitoring the influx or efflux of a highly conducting fluid (such as brine in a porous rock or blood in the human body) through the volume being imaged. For biomedical applications, this met hod does not have the resolution of radiological methods, but it is comparatively safe and inexpensive and therefore provides a valuable alternative when continuous monitoring of a patient or process is desired. The following discussion is intended first t o summarize the physics of electrical impedance tomography, then to provide a few details of the data analysis and forward modeling requirements, and finally to outline some of the reconstruction algorithms that have proven to be most useful in practice. Pointers to the literature are provided throughout this brief narrative and the reader is encouraged to explore the references for more complete discussions of the various issues raised here.

  13. Prospective study of anterior chest wall involvement in ankylosing spondylitis and psoriatic arthritis.

    PubMed

    Fournié, B; Boutes, A; Dromer, C; Sixou, L; Le Guennec, P; Granel, J; Railhac, J J

    1997-01-01

    A prospective study of anterior chest wall involvement was conducted in 50 ankylosing spondylitis patients and 50 psoriatic arthritis patients in the absence of palmoplantar pustulosis. All patients underwent a physical examination, tomograms, and a radionuclide bone scan. Magnetic resonance imaging with gadolinium was done in some cases. Half the patients in both groups had anterior chest wall involvement. Enthesitis was the mechanism of the lesions. The manubriosternal symphysis and sternocostoclavicular joints were the most common sites of involvement, although other entheses in the region were affected in some patients. PMID:9051856

  14. Rhabdomyosarcoma of the posterior chest wall in a newborn: a case report

    PubMed Central

    Gupta, Shilpi Singh; Upadhyaya, Vijay; Sharma, Shashi Shankar; Lahoti, Brijesh Kumar; Mathur, K Raj

    2009-01-01

    Rhabdomyosarcoma is the most common soft tissue malignancy of childhood, but may occur extremely rarely in the neonatal period. There are only a few reports of rhabdomyosarcoma in neonates. Although, it may arise anywhere in the body, the head and neck, and genitourinary regions are the most frequent sites. Truncal and chest wall rhabdomyosarcoma is relatively rare occurrence. We report a neonate with embryonal rhabdomyosarcoma arising from the posterior chest wall muscles at birth. Computer Tomography scan raised the possibility of rhabdomyosarcoma or neurofibroma, fine-needle aspiration cytology was inconclusive. Total excision was done and chemotherapy given. At 6 months child is without recurrence. PMID:19829867

  15. [POSSIBILITIES FOR THE SURGICAL TREATMENT OF PATIENTS WITH EXTENSIVE MALIGNANT CHEST WALL NEOPLASMS].

    PubMed

    Larin, I A; Tarasov, V A; Khubulava, G G; Gavrilov, E K

    2015-01-01

    The authors consider possibilities for the surgical treatment of patients with extensive malignant chest wall neoplasms. It is argued that combinedsugical interventions and resection of the affected parts of the chest wall together with the tumour and the use of plastic procedures allow to arrest further development of severe complications in the majority of patients and create conditions for the continuation of the anti-tumour treatment. Plastic and reconstructive surgery permits to extend operability limits and thereby improve the quality of the treatment and increase life expectancy of the patients with extensive tumorigenic process. PMID:26596058

  16. Severe Chest Wall Toxicity From Cryoablation in the Setting of Prior Stereotactic Ablative Radiotherapy.

    PubMed

    Chaudhuri, Aadel A; Binkley, Michael S; Aggarwal, Sonya; Qian, Yushen; Carter, Justin N; Shah, Rajesh; Loo, Billy W

    2016-01-01

    We present the case of a 42-year-old woman with metastatic synovial sarcoma of parotid origin, treated definitively with chemoradiation, who subsequently developed oligometastatic disease limited to the lungs. She underwent multiple left and right lung wedge resections and left lower lobectomy, followed by right lower lobe stereotactic ablative radiotherapy (SABR), 54 Gy in three fractions to a right lower lobe lesion abutting the chest wall. Two years later, she was treated with cryoablation for a separate right upper lobe nodule abutting the chest wall. Two months later, she presented with acute shortness of breath, pleuritic chest pain, decreased peripheral blood O2 saturation, and productive cough. A computed tomography (CT) scan demonstrated severe chest wall necrosis in the area of recent cryoablation that, in retrospect, also received a significant radiation dose from her prior SABR. This case demonstrates that clinicians should exercise caution in using cryoablation when treating lung tumors abutting a previously irradiated chest wall. Note: Drs. Loo and Shah contributed equally as co-senior authors. PMID:27004154

  17. Severe Chest Wall Toxicity From Cryoablation in the Setting of Prior Stereotactic Ablative Radiotherapy

    PubMed Central

    Chaudhuri, Aadel A; Binkley, Michael S; Aggarwal, Sonya; Qian, Yushen; Carter, Justin N; Shah, Rajesh

    2016-01-01

    We present the case of a 42-year-old woman with metastatic synovial sarcoma of parotid origin, treated definitively with chemoradiation, who subsequently developed oligometastatic disease limited to the lungs. She underwent multiple left and right lung wedge resections and left lower lobectomy, followed by right lower lobe stereotactic ablative radiotherapy (SABR), 54 Gy in three fractions to a right lower lobe lesion abutting the chest wall. Two years later, she was treated with cryoablation for a separate right upper lobe nodule abutting the chest wall. Two months later, she presented with acute shortness of breath, pleuritic chest pain, decreased peripheral blood O2 saturation, and productive cough. A computed tomography (CT) scan demonstrated severe chest wall necrosis in the area of recent cryoablation that, in retrospect, also received a significant radiation dose from her prior SABR. This case demonstrates that clinicians should exercise caution in using cryoablation when treating lung tumors abutting a previously irradiated chest wall. Note: Drs. Loo and Shah contributed equally as co-senior authors. PMID:27004154

  18. Evaluation of a Thermoplastic Immobilization System for Breast and Chest Wall Radiation Therapy

    SciTech Connect

    Strydhorst, Jared H.; Caudrelier, Jean-Michel; Clark, Brenda G.; Montgomery, Lynn A.; Fox, Greg; MacPherson, Miller S.

    2011-04-01

    We report on the impact of a thermoplastic immobilization system on intra- and interfraction motion for patients undergoing breast or chest wall radiation therapy. Patients for this study were treated using helical tomotherapy. All patients were immobilized using a thermoplastic shell extending from the shoulders to the ribcage. Intrafraction motion was assessed by measuring maximum displacement of the skin, heart, and chest wall on a pretreatment 4D computed tomography, while inter-fraction motion was inferred from patient shift data arising from daily image guidance procedures on tomotherapy. Using thermoplastic immobilization, the average maximum motion of the external contour was 1.3 {+-} 1.6 mm, whereas the chest wall was found to be 1.6 {+-} 1.9 mm. The day-to-day setup variation was found to be large, with random errors of 4.0, 12.0, and 4.5 mm in the left-right, superior-inferior, and anterior-posterior directions, respectively, and the standard deviations of the systematic errors were found to be 2.7, 9.8, and 4.1 mm. These errors would be expected to dominate any respiratory motion but can be mitigated by daily online image guidance. Using thermoplastic immobilization can effectively reduce respiratory motion of the chest wall and external contour, but these gains can only be realized if daily image guidance is used.

  19. Effect of shape and size of lung and chest wall on stresses in the lung

    NASA Technical Reports Server (NTRS)

    Vawter, D. L.; Matthews, F. L.; West, J. B.

    1975-01-01

    To understand better the effect of shape and size of lung and chest wall on the distribution of stresses, strains, and surface pressures, we analyzed a theoretical model using the technique of finite elements. First we investigated the effects of changing the chest wall shape during expansion, and second we studied lungs of a variety of inherent shapes and sizes. We found that, in general, the distributions of alveolar size, mechanical stresses, and surface pressures in the lungs were dominated by the weight of the lung and that changing the shape of the lung or chest wall had relatively little effect. Only at high states of expansion where the lung was very stiff did changing the shape of the chest wall cause substantial changes. Altering the inherent shape of the lung generally had little effect but the topographical differences in stresses and surface pressures were approximately proportional to lung height. The results are generally consistent with those found in the dog by Hoppin et al (1969).

  20. Use of Lumbar Perforator Recipient Vessels for Salvage Chest Wall Reconstruction: A Case Report

    PubMed Central

    Sillah, Nyama M.; Shah, Jinesh; Fukudome, Eugene

    2016-01-01

    Summary: Abdominal-based free flaps are commonly used for breast reconstruction, and the internal mammary or thoracodorsal vessels are typically used as recipient sites. Conversely, free tissue transfer is less commonly used for chest wall reconstruction in the setting of chest wall recurrence, in part, because of a paucity of recipient vessels. Here, we describe a case of a 68-year-old female smoker with metastatic breast cancer, who presented with a chest wall recurrence. There was a large area of chronic ulceration with foul smelling drainage, in addition to radiation-induced tissue injury, and palliative resection was performed. The area was reconstructed with a free transverse rectus abdominis myocutaneous flap using lumbar perforators as recipient vessels, because conventional recipient sites were unavailable because of scarring from radiation and residual tumor. This case demonstrates that uncommon recipient vessels such as lumbar perforators may allow for successful palliative chest wall reconstruction. We hypothesize that the tumor burden, previous surgeries, and radiation may have rendered the recipient field relatively ischemic, thereby inducing hypertrophy of the lumbar perforators, similar to a delay phenomenon. PMID:27257572

  1. The expanded role of extracellular matrix patch in malignant and non-malignant chest wall reconstruction in thoracic surgery†

    PubMed Central

    George, Robert S.; Kostopanagiotou, Kostas; Papagiannopoulos, Kostas

    2014-01-01

    OBJECTIVES The extracellular matrix (XCM Biologic Tissue Matrix) is a non-cross-linked 3D patch derived from porcine dermis. Once implanted, it is infiltrated by recipient's cells and becomes incorporated in the repair. Here, we report the first series of using this device for chest wall reconstruction. METHODS The XCM Biologic Tissue Matrix was utilized to provide the restoration of chest wall defects. It was used either alone or in conjunction with the Synthes titanium system to provide additional support. The decision was made intraoperatively. RESULTS Since April 2010, 21 (12 females) patients received the device. Average age at operation was 47 ± 17 years. Eleven (52%) patients had the patch inserted alone, while the remaining 10 received it in combination with another implantable medical device. The biological tissue matrix was used to reconstruct chest wall defects in cancer involving chest wall (n = 9), chest wall deformity (n = 6), chest wall hernia (n = 5) and chest wall repair following empyema drainage (n = 1). Complications were witnessed in 3 patients receiving the combined XCM and Synthes bar mechanisms; infection (n = 2) and bar displacement and infection (n = 1). CONCLUSIONS The XCM patch can be safely used to provide the strength required for chest wall reconstruction and to replace previously infected reconstructions. PMID:24263580

  2. Post mastectomy linac IMRT irradiation of chest wall and regional nodes: dosimetry data and acute toxicities

    PubMed Central

    2013-01-01

    Background Conventional post-mastectomy radiation therapy is delivered with tangential fields for chest wall and separate fields for regional nodes. Although chest wall and regional nodes delineation has been discussed with RTOG contouring atlas, CT-based planning to treat chest wall and regional nodes as a whole target has not been widely accepted. We herein discuss the dosimetric characteristics of a linac IMRT technique for treating chest wall and regional nodes as a whole PTV after modified radical mastectomy, and observe acute toxicities following irradiation. Methods Patients indicated for PMRT were eligible. Chest wall and supra/infraclavicular region +/−internal mammary nodes were contoured as a whole PTV on planning CT. A simplified linac IMRT plan was designed using either integrated full beams or two segments of half beams split at caudal edge of clavicle head. DVHs were used to evaluate plans. The acute toxicities were followed up regularly. Results Totally, 85 patients were enrolled. Of these, 45 had left-sided lesions, and 35 received IMN irradiation. Planning designs yielded 55 integrated and 30 segmented plans, with median number of beams of 8 (6–12). The integrated and segmented plans had similar conformity (1.41±0.14 vs. 1.47±0.15, p=0.053) and homogeneity indexes (0.13±0.01 vs. 0.14±0.02, p=0.069). The percent volume of PTV receiving >110% prescription dose was <5%. As compared to segmented plans, integrated plans typically increased V5 of ipsilateral lung (p=0.005), and heart (p=0.001) in patients with left-sided lesions. Similarly, integrated plans had higher spinal cord Dmax (p=0.009), ipsilateral humeral head (p<0.001), and contralateral lung Dmean (p=0.019). During follow-up, 36 (42%) were identified to have ≥ grade 2 radiation dermatitis (RD). Of these, 35 developed moist desquamation. The median time to onset of moist desquamation was 6 (4–7) weeks from start of RT. The sites of moist desquamation were most frequently occurred

  3. Respiratory kinematics by optoelectronic analysis of chest-wall motion and ultrasonic imaging of the diaphragm

    NASA Astrophysics Data System (ADS)

    Aliverti, Andrea; Pedotti, Antonio; Ferrigno, Giancarlo; Macklem, P. T.

    1998-07-01

    Although from a respiratory point of view, compartmental volume change or lack of it is the most crucial variable, it has not been possible to measure the volume of chest wall compartments directly. Recently we developed a new method based on a optoelectronic motion analyzer that can give the three-dimensional location of many markers with the temporal and spatial accuracy required for respiratory measurements. Marker's configuration has been designed specifically to measure the volume of three chest wall compartments, the pulmonary and abdominal rib cage compartments and the abdomen, directly. However, it can not track the exact border between the two rib cage compartments (pulmonary and abdominal) which is determined by the cephalic extremity of the area of apposition of the diaphragm to the inner surface of the rib cage, and which can change systematically as a result of disease processes. The diaphragm displacement can be detected by ultrasonography. In the present study, we propose an integrated system able to investigate the relationships between external (chest wall) and internal (diaphragm) movements of the different respiratory structures by simultaneous external imaging with the optoelectronic system combined with internal kinematic imaging using ultrasounds. 2D digitized points belonging to the lower lung margin, taken from ultrasonographic views, are mapped into the 3D space, where chest wall markers are acquired. Results are shown in terms of accuracy of 3D probe location, relative movement between the probe and the body landmarks, dynamic relationships between chest wall volume and position of the diaphragm during quiet breathing, slow inspirations, relaxations and exercise.

  4. Comparison of total variation algorithms for electrical impedance tomography.

    PubMed

    Zhou, Zhou; Sato dos Santos, Gustavo; Dowrick, Thomas; Avery, James; Sun, Zhaolin; Xu, Hui; Holder, David S

    2015-06-01

    The applications of total variation (TV) algorithms for electrical impedance tomography (EIT) have been investigated. The use of the TV regularisation technique helps to preserve discontinuities in reconstruction, such as the boundaries of perturbations and sharp changes in conductivity, which are unintentionally smoothed by traditional l2 norm regularisation. However, the non-differentiability of TV regularisation has led to the use of different algorithms. Recent advances in TV algorithms such as the primal dual interior point method (PDIPM), the linearised alternating direction method of multipliers (LADMM) and the spilt Bregman (SB) method have all been demonstrated successful EIT applications, but no direct comparison of the techniques has been made. Their noise performance, spatial resolution and convergence rate applied to time difference EIT were studied in simulations on 2D cylindrical meshes with different noise levels, 2D cylindrical tank and 3D anatomically head-shaped phantoms containing vegetable material with complex conductivity. LADMM had the fastest calculation speed but worst resolution due to the exclusion of the second-derivative; PDIPM reconstructed the sharpest change in conductivity but with lower contrast than SB; SB had a faster convergence rate than PDIPM and the lowest image errors. PMID:26008768

  5. Review of Chest Wall Tumors: A Diagnostic, Therapeutic, and Reconstructive Challenge

    PubMed Central

    David, Elizabeth A.; Marshall, M. Blair

    2011-01-01

    Chest wall tumors are a heterogeneous group of lesions that provide an interesting diagnostic and therapeutic challenge for surgeons. They make up less than 5% of thoracic malignancies and vary widely in pathology as they arise from all anatomic structures of the chest wall. In general, treatment is wide local excision, the margins for malignant disease are necessarily wider, and adjuvant radiation is typically given for those with positive margins. Chemotherapy is rarely effective. Local control is the most important prognostic factor. Disease-free survival for malignant disease is limited by positive margins; therefore full oncologic resection with 4-cm margins should be attempted. For small lesions, the resection and reconstruction is usually straightforward. For more advanced disease or those lesions that require significant functional loss, preoperative planning using a multidisciplinary approach, incorporating thoracic surgery, plastic surgery, neurosurgery, radiation medicine, oncology, and physical medicine and rehabilitation, may be essential. PMID:22294939

  6. Cavernous hemangioma with hematoma in the chest wall due to penetration from the anterior mediastinum.

    PubMed

    Nakamura, Hiroshige; Miwa, Ken; Miyoshi, Kenichirou; Adachi, Yoshin; Fujioka, Shinji; Taniguchi, Yuji; Yaniguchi, Yuji

    2007-04-01

    The patient was a 51-year-old man who visited the hospital with swelling of the anterior chest. Chest computed tomography detected a tumor developing from the anterior mediastinum to the anterior chest wall. There was weak contrast enhancement inside the tumor, and calcification was observed in the central region. A soft tumor with an obscure border and that adhered to the back of the left sternum was surgically removed with thymic fat including the region of the chest wall that had been penetrated by the tumor. The tumor measured 30 x 25 mm, and a phlebolith was observed in the center. The pathological tissue was diagnosed to be a cavernous hemangioma, and there were no malignant findings in the endothelial cells. Mediastinal hemangioma should therefore be kept in mind during an evaluation of mediastinal tumors, and one must also take into account the effect on the surrounding organs. PMID:17491358

  7. Chronic cutaneous chest wall fistula and gallstone empyema due to retained gallstones

    PubMed Central

    Gaster, Richard S; Berger, Aaron J; Ahmadi-Kashani, Mastaneh; Shrager, Joseph B; Lee, Gordon K

    2014-01-01

    We report a case of a 72-year-old man who presented with a persistent pleural effusion and painful abscess in the right lower chest wall 6 months following a laparoscopic cholecystectomy. The patient subsequently developed a chronic cutaneous chest wall fistula requiring a large resection and complex closure. The complication was likely secondary to intraoperative spillage of gallstones. While previous reports describe gallstone spillage in the abdominal cavity as benign, this case illustrates that stones left in the abdominal cavity can potentially lead to significant morbidity. Therefore, stones should be diligently removed from the abdominal cavity when spillage occurs. In addition, it is important that operative notes reflect the occurrence of stone spillage so stones may be suspected when a patient presents with an abdominal or thoracic infection following a cholecystectomy. PMID:25123567

  8. Reconstruction of full-thickness chest wall defects using rectus abdominis musculocutaneous flap: A report of fifteen cases

    SciTech Connect

    Miyamoto, Y.; Hattori, T.; Niimoto, M.; Toge, T. )

    1986-02-01

    In 15 patients chest walls were excised because of recurrent breast cancer, radiation ulcer, or rib tumor. In most cases the full-thickness defect of the chest wall was about 10 x 10 cm. Reconstruction was performed using only a rectus abdominis musculocutaneous flap. No patient developed circulation problems in the flap or severe flail chest, and we had successful results in all our cases. These results show that the rectus abdominis musculocutaneous flap is quite effective and safe to use in the reconstruction of chest wall defects.

  9. SU-E-T-437: Dosimetric Assessment of Brass Mesh Bolus for Postmastectomy Chest Wall Irradiation

    SciTech Connect

    Manger, R; Paxton, A; Cervino, L

    2014-06-01

    Purpose: It has been suggested that the use of a brass mesh bolus for chest wall irradiation sufficiently increases surface dose while having little effect on the dose at depth. This work quantified the increase in surface dose when using a brass mesh bolus in postmastectomy chest wall radiotherapy compared to tissue-equivalent bolus and assessed its effect on dose at depth. Methods: Percent depth doses with brass bolus, 5mm tissue-equivalent bolus, and no bolus were determined for a 6 MV photon beam in a solid water phantom using a parallel plate ionization chamber. Gafchromic film was used to determine the surface dose for the same three experimental setups. For comparison to a realistic treatment setup, gafchromic film and OSLDs were used to determine the surface dose over the irradiated area of a 6 MV chest wall plan with tangential beams delivered to a heterogeneous thorax phantom. The plan was generated using a CT of the phantom and delivered using brass mesh bolus, 5mm tissue-equivalent bolus, and no bolus. Results: For the en face beam, the central surface dose increased to 90% of maximum with the tissue-equivalent bolus, but to only 62% of maximum with the brass mesh. Using tangential beams on the thorax phantom, the surface dose increased from 40–72% to 75–110% of prescribed dose, with the brass mesh, and to 85–109% with the tissue-equivalent bolus. At depths beyond dmax in the plastic water phantom, the dose with and without brass mesh bolus differed by less than 0.5%. Conclusion: A brass mesh may be considered as a substitute for tissue-equivalent bolus to increase the superficial dose of 6 MV chest wall tangent plans. The brass mesh does not significantly change the dose at depth, so a non-bolus plan could be used for bolus and non-bolus treatments.

  10. Case of chest-wall rigidity in a preterm infant caused by prenatal fentanyl administration

    PubMed Central

    Eventov-Friedman, S; Rozin, I; Shinwell, E S

    2010-01-01

    The inability to appropriately ventilate neonates shortly after their birth could be related in rare cases to chest-wall rigidity caused by the placental transfer of fentanyl. Although this adverse effect is recognized when fentanyl is administered to neonates after their birth, the prenatal phenomenon is less known. Treatment with either naloxone or muscle relaxants reverses the fentanyl effect and may prevent unnecessary excessive ventilatory settings. PMID:20118943

  11. Multidisciplinary approach to treatment of radiation-induced chest wall sarcoma.

    PubMed

    Kara, H Volkan; Gandolfi, Brad M; Williams, Judson B; D'Amico, Thomas A; Zenn, Michael R

    2016-08-01

    Radiation-induced sarcoma (RIS) is a rare complication following therapeutic external irradiation for lung cancer patients. Patients with RIS may develop recurrence or metastasis of the previous disease and also at high risk for early chest wall complications following operation, which requires close follow-up and multidisciplinary approach. We present a challenging case of RIS with a multidisciplinary teamwork in the decision-making and successful management. PMID:25663293

  12. Surgical treatment of 125 patients with non-small cell lung cancer and chest wall involvement.

    PubMed Central

    Pitz, C. C.; Brutel de la Rivière, A.; Elbers, H. R.; Westermann, C. J.; van den Bosch, J. M.

    1996-01-01

    BACKGROUND: The optimum operative procedure for lung cancer with chest wall invasion (T3) remains controversial. In this study results of en bloc resection and extrapleural dissection are reviewed to determine survival characteristics. METHODS: Between 1977 and 1993 125 patients underwent surgery for primary non-small cell lung cancer with chest wall invasion. Patients with superior sulcus tumours, metastatic carcinomas, synchronous tumours, or recurrences were excluded. Extrapleural dissection was performed in 73 patients and en bloc resection (range 1-4 ribs) in 52. Resection was regarded as complete in 86 and incomplete in 39 patients. Actuarial survival time was estimated and risk factors for late death were identified. RESULTS: Hospital mortality was 3.2%. (n = 4). Estimated mean five year survival was 24% for all hospital survivors (n = 121), 11% for patients with incomplete resection, and 29% for patients having a complete resection. In patients who underwent complete resection mediastinal lymph node involvement and intrapleural tumour spill worsened the prognosis. Patients with adenocarcinoma had a better chance of long term survival. No relationship was found between survival and age, type of operative procedure, depth of chest wall invasion, and postoperative radiotherapy. CONCLUSIONS: Both operative procedures show reasonable survival results. Incomplete resection, mediastinal lymph node involvement, and intrapleural tumour spill adversely influence survival. PMID:8795676

  13. Reconstruction of the sternum and chest wall with methyl methacrylate: CT and MRI appearance.

    PubMed

    Gayer, G; Yellin, A; Apter, S; Rozenman, Y

    1998-01-01

    The aim of our study was to define the appearance of methyl methacrylate grafts replacing resected sternum and ribs on CT and MRI and how the sternal graft may mimic an abnormally sclerotic sternum on CT images. We reviewed the CT scans of nine patients who had undergone chest wall resection (eight with malignant and one with benign disease) and reconstruction with a composite of methyl methacrylate and Marlex mesh graft. One of them had an MRI study as well. The size, shape and CT attenuation were assessed on mediastinal and bone window settings. The sternal graft was seen on mediastinal and even better on bone windows as an abnormally wide, irregularly shaped structure, somewhat denser than the normal sternum. The chest wall prosthesis replacing resected ribs was seen as a continuous dense structure and of similar attenuation as that of the sternal graft. On MRI the prosthesis appeared as a well-defined structure with no signal. Reconstruction of the chest wall with methyl methacrylate appears on CT as a diffusely dense sclerotic bone lesion not unlike a malignant lesion. The possibility of a graft has to be included in the differential diagnosis in these cases. PMID:9477274

  14. Unusual chest wall pain caused by thoracic disc herniation in a professional baseball pitcher.

    PubMed

    Kato, Kinshi; Yabuki, Shoji; Otani, Koji; Nikaido, Takuya; Otoshi, Ken-Ichi; Watanabe, Kazuyuki; Kikuchi, Shin-Ichi; Konno, Shin-Ichi

    2016-06-01

    Symptomatic thoracic disc herniation is clinically rare. There are few cases of disc herniation of the thoracic spine in top athletes described in the literature. We herein present a rare case of chest wall pain due to thoracic disc herniation in a professional baseball pitcher. A 30-year-old, left-handed pitcher complained of left-sided chest wall pain in the region of his lower ribs during a game. Neurological examination revealed hypoesthesia of the left side of the chest at the level of the lower thoracic spine. Magnetic resonance imaging (MRI) of the thoracic spine showed a left-sided paramedian disc herniation at the T9-T10 level. The player was initially prescribed rest, administration of pregabalin (150 mg twice a day), and subsequent physical rehabilitation. He was able to resume full training and pitching without medication 6 months after the onset. A follow-up MRI of the thoracic spine showed a reduction in the size of the herniated disc compared to the initial findings. Though relatively rare, thoracic disc herniation should be considered in cases of chest wall pain in athletes. PMID:26983590

  15. Long-term survival after chest-wall reconstruction with musculocutaneous flaps

    SciTech Connect

    Kroll, S.S.; Schusterman, M.A.; Larson, D.L.; Fender, A. )

    1990-10-01

    Reconstruction of chest-wall defects with musculocutaneous flaps permits resection of advanced chest-wall tumors and of tissues severely damaged by radiotherapy in patients who in a previous era were not surgically treatable. To determine the long-term outcome from this surgery, the records of 96 patients who had undergone chest-wall resection with musculocutaneous flap reconstruction were reviewed. Median survival for the entire group was 20.5 months, but a more accurate prediction of outcome could be obtained by dividing the patients into three groups. In group I, patients free of known malignancy and undergoing resection of radionecrotic tissues, median survival was 60.0 months. In group II, patients with resectable disease and free of tumor following surgery, median survival was 31.1 months. In group III, patients incompletely resected or known to have metastatic disease following surgery, median survival was only 12.5 months. Even in group III, however, some individuals achieved prolonged survival and lasting benefits from the surgery, so these data should not be used to exclude patients from undergoing necessary palliative procedures.

  16. Color structured light system of chest wall motion measurement for respiratory volume evaluation

    NASA Astrophysics Data System (ADS)

    Chen, Huijun; Cheng, Yuan; Liu, Dongdong; Zhang, Xiaodong; Zhang, Jue; Que, Chengli; Wang, Guangfa; Fang, Jing

    2010-03-01

    We present a structured light system to dynamically measure human chest wall motion for respiratory volume estimation. Based on a projection of an encoded color pattern and a few active markers attached to the trunk, respiratory volumes are obtained by evaluating the 3-D topographic changes of the chest wall in an anatomically consistent measuring region during respiration. Three measuring setups are established: a single-sided illuminating-recording setup for standing posture, an inclined single-sided setup for supine posture, and a double-sided setup for standing posture. Results are compared with the pneumotachography and show good agreement in volume estimations [correlation coefficient: R>0.99 (P<0.001) for all setups]. The isovolume tests present small variations of the obtained volume during the isovolume maneuver (standard deviation<0.085 L for all setups). After validation by the isovolume test, an investigation of a patient with pleural effusion using the proposed method shows pulmonary functional differences between the diseased and the contralateral sides of the thorax, and subsequent improvement of this imbalance after drainage. These results demonstrate the proposed optical method is capable of not only whole respiratory volume evaluation with high accuracy, but also regional pulmonary function assessment in different chest wall behaviors, with the advantage of whole-field measurement.

  17. Estimating adipose tissue in the chest wall using ultrasonic and alternate /sup 40/K and biometric measurements

    SciTech Connect

    Anderson, A.L.; Campbell, G.W.

    1982-01-22

    The percentage of adipose (fat) tissue in the chest wall must be known to accurately measure Pu in the human lung. Correction factors of 100% or more in x-ray detection efficiency are common. Methods using simple /sup 40/K and biometric measurement techniques were investigated to determine the adipose content in the human chest wall. These methods predict adipose content to within 15% of the absolute ultrasonic value. These new methods are discussed and compared with conventional ultrasonic measurement techniques. (ERB)

  18. Transcatheter Arterial Embolization for Tumor Seeding in the Chest Wall After Radiofrequency Ablation for Hepatocellular Carcinoma

    SciTech Connect

    Shibata, Toshiya Shibata, Toyomichi; Maetani, Yoji; Kubo, Takeshi; Nishida, Naoshi; Itoh, Kyo

    2006-06-15

    Tumor seeding in the chest wall was depicted at follow-up CT obtained 9 months after radiofrequency ablation for hepatocellular carcinoma. Transcatheter arterial embolization was successfully performed, injecting emulsion of 10 mg of epirubicin and 1 ml of iodized oil followed by gelatin sponge particles via the microcatheter placed in the right eleventh intercostal artery. The patient died of tumor growth in the liver one year after the embolization, but no progression of the tumor seeding was noted during the follow-up period. We conclude that transcatheter arterial embolization was effective for the control of tumor seeding after radiofrequency ablation for hepatocellular carcinoma.

  19. [Castleman's Disease of the Chest Wall Successfully Resected by Thoracoscopic Surgery;Report of a Case].

    PubMed

    Naomi, Akira; Kuroda, Hiroaki; Seto, Katsutoshi; Iiduka, Shuhei; Dejima, Hitoshi; Mizuno, Tetsuya; Sakakura, Noriaki; Sakao, Yukinori

    2015-12-01

    A 61-year-old woman without a significant past medical history was pointed out the abnormal shadow on the annual medical checkup. Chest computed tomography (CT) revealed a well-defined paravertebral chest wall tumor of 20 mm in maxmum size. Furthermore, diffusion weighted image on magnetic resonance imaging (MRI) showed high intensity, and standardized uptake value (SUV) max on positron emission tomography/computed tomography (PET/CT) was 13.4. Schwanoma, solitary fibrous tumor (SFT) or malignant lymphoma was suggested. Complete resection was performed with thoracoscopic surgery. The histological diagnosis was Castleman's disease with hyalineized type. PMID:26759958

  20. The Etiologies of Chest Wall and Breast Asymmetry and Improvement in Breast Augmentation.

    PubMed

    Glicksman, Caroline A; Ferenz, Sarah E

    2015-10-01

    Patients presenting for correction of breast and chest wall asymmetries may have undergone numerous thoracic procedures in early childhood and may have suffered profound psychosocial effects. Complex congenital syndromes as well as mild breast asymmetries should be carefully documented using objective measurements, photography, and 3-dimensional simulations when available. Shaped highly cohesive breast implants offer plastic surgeons more possibilities and precision by fine-tuning the gel distribution and specific volumes required to correct the hypoplastic elements. Long-lasting correction of asymmetry can be obtained when patients are not oversized, and care is taken to avoid visibility, palpability, and malposition problems. PMID:26408441

  1. Fireworks-induced chest wall granulomatous disease: 18F-FDG PET/CT imaging.

    PubMed

    Le, Stephanie T; Nguyen, Ba Duong

    2014-04-01

    The authors present a case of 18F-FDG-avid granulomatous reaction induced by fireworks injury of the chest wall in a patient with esophageal adenocarcinoma. This hypermetabolic lesion, involving the right pectoralis muscles, appeared slightly more prominent on restaging PET/CT imaging following chemotherapy and radiation therapy. Excisional biopsy of the lesion established the diagnosis of foreign-body granulomatous-type inflammation with surrounding foci of non-polarizable black foreign material and ruled out malignancy. The patient recalled accidentally shooting himself in the chest with a Roman candle at the age of 3. PMID:23877517

  2. Factors Associated With Chest Wall Toxicity After Accelerated Partial Breast Irradiation Using High-Dose-Rate Brachytherapy

    SciTech Connect

    Brown, Sheree; Vicini, Frank; Vanapalli, Jyotsna R.; Whitaker, Thomas J.; Pope, D. Keith; Lyden, Maureen; Bruggeman, Lisa; Haile, Kenneth L.; McLaughlin, Mark P.

    2012-07-01

    Purpose: The purpose of this analysis was to evaluate dose-volume relationships associated with a higher probability for developing chest wall toxicity (pain) after accelerated partial breast irradiation (APBI) by using both single-lumen and multilumen brachytherapy. Methods and Materials: Rib dose data were available for 89 patients treated with APBI and were correlated with the development of chest wall/rib pain at any point after treatment. Ribs were contoured on computed tomography planning scans, and rib dose-volume histograms (DVH) along with histograms for other structures were constructed. Rib DVH data for all patients were sampled at all volumes {>=}0.008 cubic centimeter (cc) (for maximum dose related to pain) and at volumes of 0.5, 1, 2, and 3 cc for analysis. Rib pain was evaluated at each follow-up visit. Patient responses were marked as yes or no. No attempt was made to grade responses. Eighty-nine responses were available for this analysis. Results: Nineteen patients (21.3%) complained of transient chest wall/rib pain at any point in follow-up. Analysis showed a direct correlation between total dose received and volume of rib irradiated with the probability of developing rib/chest wall pain at any point after follow-up. The median maximum dose at volumes {>=}0.008 cc of rib in patients who experienced chest wall pain was 132% of the prescribed dose versus 95% of the prescribed dose in those patients who did not experience pain (p = 0.0035). Conclusions: Although the incidence of chest wall/rib pain is quite low with APBI brachytherapy, attempts should be made to keep the volume of rib irradiated at a minimum and the maximum dose received by the chest wall as low as reasonably achievable.

  3. Dosimetric evaluation of integrated IMRT treatment of the chest wall and supraclavicular region for breast cancer after modified radical mastectomy

    SciTech Connect

    Yang, Bo; Wei, Xian-ding; Zhao, Yu-tian; Ma, Chang-Ming

    2014-07-01

    To investigate the dosimetric characteristics of irradiation of the chest wall and supraclavicular region as an integrated volume with intensity-modulated radiation therapy (IMRT) after modified radical mastectomy. This study included 246 patients who received modified radical mastectomy. The patients were scanned with computed tomography, and the chest wall (with or without the internal mammary lymph nodes) and supraclavicular region were delineated. For 143 patients, the chest wall and supraclavicular region were combined as an integrated planning volume and treated with IMRT. For 103 patients, conventional treatments were employed with 2 tangential fields for the chest wall, abutting a mixed field of 6-MV x-rays (16 Gy) and 9-MeV electrons (34 Gy) for the upper supraclavicular region. The common prescription dose was 50 Gy/25 Fx/5 W to 90% of the target volume. The dosimetric characteristics of the chest wall, the supraclavicular region, and normal organs were compared. For the chest wall target, compared with conventional treatments, the integrated IMRT plans lowered the maximum dose, increased the minimum dose, and resulted in better conformity and uniformity of the target volume. There was an increase in minimum, average, and 95% prescription dose for the integrated IMRT plans in the supraclavicular region, and conformity and uniformity were improved. The V{sub 30} of the ipsilateral lung and V{sub 10}, V{sub 30}, and mean dose of the heart on the integrated IMRT plans were lower than those of the conventional plans. The V{sub 5} and V{sub 10} of the ipsilateral lung and V{sub 5} of the heart were higher on the integrated IMRT plans (p < 0.05) than on conventional plans. Without an increase in the radiation dose to organs at risk, the integrated IMRT treatment plans improved the dose distribution of the supraclavicular region and showed better dose conformity and uniformity of the integrated target volume of the chest wall and supraclavicular region.

  4. Chest wall deformities and thoracic scoliosis after costal cartilage graft harvesting.

    PubMed

    Ohara, K; Nakamura, K; Ohta, E

    1997-04-01

    Donor-site complications, specifically chest wall deformities and thoracic scoliosis, occurring after harvest of costal cartilage grafts are presented and discussed. The cases of 18 patients (12 male and 6 female), who underwent costal cartilage grafts for microtia reconstruction from 1975 to 1993, were reviewed for donor-site complications using radiography and physical examination. Ribs from which costal cartilage had been harvested showed increased inward bowing on radiographs in 16 of 32 donor sites. The frequency of rib deformity in donor sites was 20.0 percent when cartilages were harvested from patients older than 10 years of age, whereas it was 63.6 percent in patients younger than 10 years old. This difference was statistically significant (p = 0.027, Fisher's exact test), although only 32 grafts were performed in 18 cases. The upper ribs demonstrate a higher incidence of deformity than lower ribs. Thoracic scoliosis was found in 4 of 16 cases. The biomechanical impact of these deformities was considered because of respiratory movement of the thorax and injury to the germinal growth center of the ribs. We recommend delaying costal cartilage grafts for as long as possible, leaving the costochondral junction intact to minimize chest wall deformity and thoracic scoliosis. PMID:9091899

  5. Compartmental chest wall volume changes during volitional hyperpnoea with constant tidal volume in healthy individuals.

    PubMed

    Illi, Sabine K; Hostettler, Stefanie; Aliverti, Andrea; Spengler, Christina M

    2013-01-15

    Prolonged high-intensity ventilation is associated with the development of rapid shallow breathing with decreased end-inspiratory volumes of all chest wall compartments. During respiratory muscle endurance training using normocapnic hyperpnoea, tidal volume (V(T)) is normally kept constant. The aim of this study was to investigate possible changes in muscle recruitment during constant-V(T) hyperpnoea, to assess potential mechanisms related to rapid shallow breathing. Ten healthy subjects performed 1h of normocapnic hyperpnoea at 70% of maximal voluntary ventilation. Chest wall volume changes were assessed by optoelectronic plethysmography. End-inspiratory (1.08 ± 0.18 versus 0.96 ± 0.27 l, p=0.017) and end-expiratory volumes (-0.13 ± 0.15 versus -0.31 ± 0.19 l, p=0.007) of the pulmonary ribcage decreased significantly and lung function and respiratory muscle strength were reduced (all p<0.05). Since with forced, constant V(T) only the inspiratory rib cage muscles were unable to sustain end-inspiratory volume of their compartment, inspiratory rib cage muscles are the most likely candidate responsible for the development of rapid shallow breathing. PMID:22959999

  6. Assessment of skin dose for breast chest wall radiotherapy as a function of bolus material

    NASA Astrophysics Data System (ADS)

    Hsu, Shu-Hui; Roberson, Peter L.; Chen, Yu; Marsh, Robin B.; Pierce, Lori J.; Moran, Jean M.

    2008-05-01

    Skin dose assessment for chest wall radiotherapy is important to ensure sufficient dose to the surface target volume without excessive skin reaction. This study quantified changes to the surface doses as a function of bolus material for conventional and intensity modulated radiation therapy (IMRT) tangential fields. Three types of bolus materials (2 mm solid, 2 mm fine mesh and 3.2 mm large mesh Aquaplast) were compared with Superflab. Surface dose measurements were performed using an Attix parallel plate chamber in a flat solid water phantom at 0°, 45° and 70° incident angles. Over-response correction factors were applied to the Attix chamber results for different incident angles. Surface dose measurements on an anthropomorphic phantom were done using a thermoluminescent dosimeter extrapolation method. Dose characteristics of Superflab and solid Aquaplast were within 2% of solid water material. No significant differences (within 3%) in the surface dose were found between conventional and IMRT tangential techniques. The bolus effect was large for chest wall tangential radiotherapy, with up to an 82% increase using 2 mm fine mesh Aquaplast. The dosimetric effect of different Aquaplast materials has been quantified in this work. These materials can be used to create a custom bolus with potentially better reproducibility of placement.

  7. Chest wall hernia induced by high intensity focused ultrasound treatment of unresectable massive hepatocellular carcinoma: A case report

    PubMed Central

    CHEN, QI-WEN; TENG, WEN-JING; CHEN, QIAN

    2016-01-01

    In the present study, a case of unresectable massive hepatocellular carcinoma (HCC) treated with high intensity focused ultrasound (HIFU) alone is reported. Although the treatment induced chest wall hernia, its efficacy in treating the HCC was demonstrated. The medical records of a patient with an unresectable massive tumor that was effectively treated with serial HIFU ablation were retrospectively studied. Chest wall hernia was detected as a complication of the HIFU treatment, which has not been reported thus far in the literature. The patient has survived for 44 months since the first diagnosis in September 2010. Treatment resulted in partial remission of the tumor, pain relief, decreased levels of alpha-fetoprotein and chest wall hernia, as a complication. Therefore, HIFU may be an effective approach for the treatment of unresectable HCC, although it may occasionally cause complications. PMID:27347191

  8. Validation of an Objective Assessment Instrument for Non-Surgical Treatments of Chest Wall Deformities.

    PubMed

    Obeid, Mohammad F; Kidane, Nahom; Rechowicz, Krzysztof J; Chemlal, Salim; Kelly, Robert E; Mckenzie, Frederic D

    2016-01-01

    Depending on the severity of the condition and associated risk, surgical intervention may not always be the first choice. This is true for treating chest wall deformities such as pectus excavatum and pectus carinatum. For both conditions, novel non-surgical treatments have been developed to gradually alleviate the malformation making use of the elastic nature of the costal cartilages at an early age of the patient. To quantify the performance of such treatments, this paper introduces and discusses the development of a software-based instrument that utilizes 3D chest optical images (surface scans) as input and uses registration techniques to produce an objective gauge of a patient's physical improvement after undergoing treatments. Further discussed is an experiment designed to investigate the construct validity of the developed instrument. PMID:27046591

  9. High-Frequency Chest Wall Oscillation Successful in Controlling Refractory Asthma

    PubMed Central

    BOSE, SONALI; JUN, JONATHAN; DIETTE, GREGORY B.

    2016-01-01

    Introduction High-frequency chest wall oscillation (HFCWO) has been traditionally implemented for airway secretion clearance in conditions such as cystic fibrosis (CF) and bronchiectasis. There have been few reports of its use in refractory asthma. Case report A 36-year-old, non-smoker male presented with a lifelong history of poorly controlled asthma. Despite multiple controller medications, he reported daily chest congestion, copious phlegm, and frequent exacerbations. Imaging, blood work, and bronchoscopy ruled out atypical infections, immunodeficiency, CF, and other chronic conditions. Pulmonary function tests supported a diagnosis of asthma. Results We initiated HFCWO therapy twice daily in addition to standard inhaled pharmacological therapy. After 2 months, the patient noted resolution of respiratory symptoms as well as improvement in lung function. He remained symptom-free at his 2-year follow-up. Conclusion High-frequency chest oscillation may be useful in phenotypes of asthma characterized by prominent mucus hypersecretion. PMID:23394251

  10. Plasma Cell Leukemia Presenting as a Chest Wall Mass: A Case Report

    PubMed Central

    Ali, Ahmed; Paul, Yonette; Nwabudike, Stanley Madu; Ogbonna, Onyekachi; Grantham, Mica; Taddesse-Heath, Lekidelu

    2016-01-01

    Plasma cell leukemia (PCL) is an uncommon neoplasm of plasma cells, with an aggressive clinical course and poor outcome, even with current standard of care. It can occur either de novo (primary PCL) or as a progression of multiple myeloma (MM). This disease has unique diagnostic criteria but certain genetic markers and clinical features may overlap with MM. Due to the low prevalence of PCL, guidelines on its management are extrapolated from the management of MM and based on small retrospective studies and cases reports/series. We present an interesting case of PCL in a middle-aged African-American male, who was diagnosed incidentally after chest wall imaging for an unrelated complaint. The diagnostic approach, management and outcomes of PCL are discussed. PMID:27462235

  11. Chest wall thickness in military personnel: implications for needle thoracentesis in tension pneumothorax.

    PubMed

    Harcke, H Theodore; Pearse, Lisa A; Levy, Angela D; Getz, John M; Robinson, Stephen R

    2007-12-01

    Needle thoracentesis is an emergency procedure to relieve tension pneumothorax. Published recommendations suggest use of angiocatheters or needles in the 5-cm range for emergency treatment. Multidetector computed tomography scans from 100 virtual autopsy cases were used to determine chest wall thickness in deployed male military personnel. Measurement was made in the second right intercostal space at the midclavicular line. The mean horizontal thickness was 5.36 cm (SD = 1.19 cm) with angled (perpendicular) thickness slightly less with a mean of 4.86 cm (SD 1.10 cm). Thickness was generally greater than previously reported. An 8-cm angiocatheter would have reached the pleural space in 99% of subjects in this series. Recommended procedures for needle thoracentesis to relieve tension pneumothorax should be adapted to reflect use of an angiocatheter or needle of sufficient length. PMID:18274025

  12. [Sudden death caused by a less lethal weapon chest-wall injury (Commotio cordis)].

    PubMed

    Contargyris, C; Peytel, E

    2012-05-01

    Less lethal weapons, like Flashball, are more and more used since 1995 in law enforcement, even by the local police to neutralize combative individuals and to disperse riot crowds. This gun fires large rubber bullets and has been incriminated many times in cases of face injuries with functional consequences. In this case report, we mention a case of sudden death from cardiac arrest due to low energy chest wall impact of a rubber bullet shot with the Flashball. Commotio cordis is potentialized by a lethal set of three including, a certain impact velocity, an exact location of the hit over the cardiac silhouette, and a precise timing 15 m/s prior to the peak of the T-wave. This case report highlights the fact that such impacts can cause significant injury to internal organs, in particular circonstances, implying the necessity of a raising awareness of the medical staff, in ordre to not underestimate the severity of such injuries. PMID:22487658

  13. Malignant triton tumor of the chest wall invading the lung. A case report and literature review

    PubMed Central

    Kamperis, E; Barbetakis, N; Asteriou, C; Kleontas, A; Christoforidou, V

    2013-01-01

    Background: Malignant triton tumor (MTT) is an histological deviation of malignant peripheral nerve sheath tumor with additional rhabdomyosarcomatous elements. It is very rare, profoundly aggressive, with a tendency to recur locally and metastasize early. If manifests itself more often in individuals with neurofibromatosis type I (NF-1) disease but also sporadically or post radiotherapy. Description of case: A 57-year-old male was admitted with a history of malignant triton tumor of the chest wall. Despite prior aggressive locoregional treatment including wide excision and adjuvant consolidating radiotherapy, the tumor recurred. The patient underwent a new operation and systemic chemotherapy, but expired a few months later due to disease progression. Conclusion: MTT is exceedingly malignant requiring multimodality treatment. The cornerstone of management is radical surgical resection with clear margins. Nevertheless, the overall prognosis remains dismal. PMID:24470743

  14. Carcinoma originating from aberrant breast tissue of the right upper anterior chest wall : a case report.

    PubMed Central

    Rho, J. Y.; Juhng, S. K.; Yoon, K. J.

    2001-01-01

    Aberrant breast tissue is usually found in proximity to the normal breast, that is, in the axillary, sternal or clavicular regions. Carcinoma occurs more frequently in the aberrant tissue of the axilla than the extra-axillary site though the overall incidence of tumors of aberrant breast tissue is low. To our knowledge, studies regarding the carcinoma of aberrant breast tissue of the extra-axillary site have been reported rarely. Here we report a recent case of carcinoma originating from the extra-axillary aberrant breast tissue, presenting as a subcutaneous nodule on the right upper anterior chest wall. It is suggested that subcutaneous nodules of uncertain origin around the periphery of the breast should be suspected for breast carcinoma as a differential diagnosis and treated properly. PMID:11511802

  15. Laser based method for real-time three-dimensional monitoring of chest wall movement

    NASA Astrophysics Data System (ADS)

    Jezeršek, Matija; Povšič, Klemen; Topole, Eva; Fležar, Matjaž; Možina, Janez

    2010-05-01

    Novel method for monitoring the entire three-dimensional shape of the chest wall in real time is presented. The system is based on the multiple-line laser triangulation principle. The laser projector generates a light pattern of 33 equally inclined light planes directed toward the measured surface. The camera records the illuminated surface from a different viewpoint, and consequently, the light pattern is distorted by the shape of the surface. The acquired images are transferred in the personal computer, where contour detection, three-dimensional surface reconstruction, shape analysis, and displaying are performed in real time. Surface displacements are calculated by subtraction of the current measured surface from the reference one. Differences are displayed with color palette, where the blue represent the inward (negative) and the red represent the outward (positive) movement. The accuracy of the calibrated apparatus is +/-0.5 mm, which is calculated as a standard deviation between points of the measured and nominal reference surface. The measuring range is approximately 400×600×500 mm in width, height and depth. The intention of this study was to evaluate the system by means of its ability to distinguish between different breathing patterns and to verify the accuracy of measuring chest wall deformation volumes during breathing. The results demonstrate that the presented 3-d measuring system has a great potential as a diagnostic and training tool in case of monitoring the breathing pattern. We believe that exact graphical communication with the patient is much more simple and easy to understand than verbal and/or numerical.

  16. Chest Wall Ewing Sarcoma Family of Tumors: Long-Term Outcomes

    SciTech Connect

    Indelicato, Daniel J.; Keole, Sameer R.; Lagmay, Joanne P.; Morris, Christopher G.; Gibbs, C. Parker; Scarborough, Mark T.; Islam, Saleem; Marcus, Robert B.

    2011-09-01

    Purpose: To review the 40-year University of Florida experience treating Ewing sarcoma family of tumors of the chest wall. Methods and Materials: Thirty-nine patients were treated from 1966 to 2006. Of the patients, 22 were treated with radiotherapy (RT) alone, and 17 patients were treated with surgery with or without RT. Of 9 patients with metastatic disease, 8 were treated with RT alone. The risk profiles of each group were otherwise similar. The median age was 16.6 years, and the most frequent primary site was the rib (n = 17). The median potential follow-up was 19.2 years. Results: The 5-year actuarial overall survival (OS), cause-specific survival (CSS), and local control (LC) rates were 34%, 34%, and 72%, respectively. For the nonmetastatic subset (n = 30), the 5-year OS, CSS, and LC rates were 44%, 44%, and 79%, respectively. LC was not statistically significantly different between patients treated with RT alone (61%) vs. surgery + RT (75%). None of the 4 patients treated with surgery alone experienced local failure. No patient or treatment variable was significantly associated with local failure. Of the patients, 26% experienced Common Toxicity Criteria (CTC) Grade 3+ toxicity, including 2 pulmonary deaths. Modern intensive systemic therapy helped increase the 5-year CSS from 7% to 49% in patients treated after 1984 (p = 0.03). Conclusions: This is the largest single-institution series describing the treatment of chest wall Ewing tumors. Despite improvements in survival, obtaining local control is challenging and often accompanied by morbidity. Effort should be focused on identifying tumors amenable to combined-modality local therapy and to improving RT techniques.

  17. Biometric estimation of chest wall thickness of female radiation workers as an aid in in-vivo detection of the actinides

    SciTech Connect

    Lane, B.H.; Berger, C.D.

    1983-01-01

    An equation was derived to estimate female chest wall thickness from a series of biometric measurements. This technique will result in improved performance for actinide detection in females by accounting for variations in chest wall thickness in derivation of calibration factors.

  18. Effects of chest wall compression on expiratory flow rates in patients with chronic obstructive pulmonary disease

    PubMed Central

    Nozoe, Masafumi; Mase, Kyoshi; Ogino, Tomoyuki; Murakami, Shigefumi; Takashima, Sachie; Domen, Kazuhisa

    2016-01-01

    Background: Manual chest wall compression (CWC) during expiration is a technique for removing airway secretions in patients with respiratory disorders. However, there have been no reports about the physiological effects of CWC in patients with chronic obstructive pulmonary disease (COPD). Objective: To compare the effects of CWC on expiratory flow rates in patients with COPD and asymptomatic controls. Method: Fourteen subjects were recruited from among patients with COPD who were receiving pulmonary rehabilitation at the University Hospital (COPD group). Fourteen age-matched healthy subjects were also consecutively recruited from the local community (Healthy control group). Airflow and lung volume changes were measured continuously with the subjects lying in supine position during 1 minute of quiet breathing (QB) and during 1 minute of CWC by a physical therapist. Results: During CWC, both the COPD group and the healthy control group showed significantly higher peak expiratory flow rates (PEFRs) than during QB (mean difference for COPD group 0.14 L/sec, 95% confidence interval (CI) 0.04 to 0.24, p<0.01, mean difference for healthy control group 0.39 L/sec, 95% CI 0.25 to 0.57, p<0.01). In the between-group comparisons, PEFR was significantly higher in the healthy control group than in the COPD group (-0.25 L/sec, 95% CI -0.43 to -0.07, p<0.01). However, the expiratory flow rates at the lung volume at the PEFR during QB and at 50% and 25% of tidal volume during QB increased in the healthy control group (mean difference for healthy control group 0.31 L/sec, 95% CI 0.15 to 0.47, p<0.01: 0.31 L/sec, 95% CI 0.15 to 0.47, p<0.01: 0.27 L/sec, 95% CI 0.13 to 0.41, p<0.01, respectively) but not in the COPD group (0.05 L/sec, 95% CI -0.01 to 0.12: -0.01 L/sec, 95% CI -0.11 to 0.08: 0.02 L/sec, 95% CI -0.05 to 0.90) with the application of CWC. Conclusion: The effects of chest wall compression on expiratory flow rates was different between COPD patients and asymptomatic

  19. Measurement of radiotherapy x-ray skin dose on a chest wall phantom.

    PubMed

    Quach, K Y; Morales, J; Butson, M J; Rosenfeld, A B; Metcalfe, P E

    2000-07-01

    Sufficient skin dose needs to be delivered by a radiotherapy chest wall treatment regimen to ensure the probability of a near surface tumor recurrence is minimized. To simulate a chest wall treatment a hemicylindrical solid water phantom of 7.5 cm radius was irradiated with 6 MV x-rays using 20x20 cm2 and 10x20 cm2 fields at 100 cm source surface distance (SSD) to the base of the phantom. A surface dose profile was obtained from 0 to 180 degrees, in 10 degrees increments around the circumference of the phantom. Dosimetry results obtained from radiochromic film (effective depth of 0.17 mm) were used in the investigation, the superficial doses were found to be 28% (of Dmax) at the 0 degrees beam entry position and 58% at the 90 degrees oblique beam position. Superficial dose results were also obtained using extra thin thermoluminescent dosimeters (TLD) (effective depth 0.14 mm) of 30% at 0 degrees, 57% at 90 degrees, and a metal oxide semiconductor field effect transistor (MOSFET) detector (effective depth 0.5 mm) of 43% at 0 degrees, 62% at 90 degrees. Because the differences in measured superficial doses were significant and beyond those related to experimental error, these differences are assumed to be mostly attributable to the effective depth of measurement of each detector. We numerically simulated a bolus on/bolus off technique and found we could increase the coverage to the skin. Using an alternate "bolus on," "bolus off" regimen, the skin would receive 36.8 Gy at 0 degrees incidence and 46.4 Gy at 90 degrees incidence for a prescribed midpoint dose of 50 Gy. From this work it is evident that, as the circumference of the phantom is traversed the SSD increases and hence there is an inverse square fluence fall-off, this is more than offset by the increase in skin dose due to surface curvature to a plateau at about 90 degrees. Beyond this angle it is assumed that beam attenuation through the phantom and inverse square fall-off is causing the surface dose to

  20. Impedance learning for robotic contact tasks using natural actor-critic algorithm.

    PubMed

    Kim, Byungchan; Park, Jooyoung; Park, Shinsuk; Kang, Sungchul

    2010-04-01

    Compared with their robotic counterparts, humans excel at various tasks by using their ability to adaptively modulate arm impedance parameters. This ability allows us to successfully perform contact tasks even in uncertain environments. This paper considers a learning strategy of motor skill for robotic contact tasks based on a human motor control theory and machine learning schemes. Our robot learning method employs impedance control based on the equilibrium point control theory and reinforcement learning to determine the impedance parameters for contact tasks. A recursive least-square filter-based episodic natural actor-critic algorithm is used to find the optimal impedance parameters. The effectiveness of the proposed method was tested through dynamic simulations of various contact tasks. The simulation results demonstrated that the proposed method optimizes the performance of the contact tasks in uncertain conditions of the environment. PMID:19696001

  1. A Simple and Robust Event-Detection Algorithm for Single-Cell Impedance Cytometry.

    PubMed

    Caselli, Federica; Bisegna, Paolo

    2016-02-01

    Microfluidic impedance cytometry is emerging as a powerful label-free technique for the characterization of single biological cells. In order to increase the sensitivity and the specificity of the technique, suited digital signal processing methods are required to extract meaningful information from measured impedance data. In this study, a simple and robust event-detection algorithm for impedance cytometry is presented. Since a differential measuring scheme is generally adopted, the signal recorded when a cell passes through the sensing region of the device exhibits a typical odd-symmetric pattern. This feature is exploited twice by the proposed algorithm: first, a preliminary segmentation, based on the correlation of the data stream with the simplest odd-symmetric template, is performed; then, the quality of detected events is established by evaluating their E2O index, that is, a measure of the ratio between their even and odd parts. A thorough performance analysis is reported, showing the robustness of the algorithm with respect to parameter choice and noise level. In terms of sensitivity and positive predictive value, an overall performance of 94.9% and 98.5%, respectively, was achieved on two datasets relevant to microfluidic chips with very different characteristics, considering three noise levels. The present algorithm can foster the role of impedance cytometry in single-cell analysis, which is the new frontier in "Omics." PMID:26241968

  2. Lung volumes, chest wall configuration, and pattern of breathing in microgravity.

    PubMed

    Paiva, M; Estenne, M; Engel, L A

    1989-10-01

    We studied the changes in functional residual capacity (FRC), thoracoabdominal volume (Vw), and chest wall configuration in five normal subjects seated in an aircraft flying parabolic trajectories resulting in 20-s periods of microgravity. We measured vital capacity (VC), inspiratory capacity, and tidal volume by integrating airflow at the mouth and changes in rib cage and abdominal volume (delta Vrc and delta Vab, respectively, where delta Vrc + delta Vab = delta Vw) using induction plethysmography. During microgravity (0 Gz) FRC decreased by 413 +/- 70 (SE) ml and VC by 0.37 liter. The decrease in Vw did not differ from that in FRC and was entirely the result of reduction of Vab, the Vrc showing no significant change. During tidal breathing the abdominal contribution (delta Vab/delta Vw) increased from 0.39 +/- 0.08 at 1 Gz to 0.57 +/- 0.08 at 0 Gz. During brief periods of hypergravity (approximately 1.8 Gz) all changes were opposite in sign and relatively smaller. Limited data during "roller coaster" flight patterns suggested that, in contrast to configurational changes, the temporal pattern of breathing was uninfluenced by changes in Gz. We conclude that at the onset of weightlessness there are substantial changes in lung volume and thoracoabdominal configuration. Abdominal contribution to tidal excursions increases but the temporal pattern of breathing is unchanged. PMID:2793756

  3. Sonic phase delay from trachea to chest wall: spatial and inhaled gas dependency.

    PubMed

    Patel, S; Lu, S; Doerschuk, P C; Wodicka, G R

    1995-07-01

    A parametric phase delay estimation technique is used to determine the spatial and inhaled gas composition dependencies of sound propagation time through an intact human lung at frequencies of 150-1200 Hz. Noise transmission measurements from the mouth to the extrathoracic trachea and six sites on the posterior chest wall are performed in 11 healthy adult subjects at resting lung volume after equilibration with air, an 80% helium-20% oxygen mixture, and an 80% sulfurhexafluoride-20% oxygen mixture. The phase delay, tau(f), exhibits a bilateral asymmetry with relatively decreased delays to the left posterior chest as compared with the right. The phase delay to lower lung sites is greater than to upper sites at frequencies below 300 Hz; yet the opposite is found at higher frequencies, indicating changing propagation pathways with frequency. There is no measurable effect of inhaled gas composition on tau(f) below 300 Hz. At higher frequencies, changes in tau(f) that reflect the relative sound speed of the particular inhaled gas are observed. These findings support and extend previous measurements and hypotheses concerning the strong frequency dependence of the acoustical properties of the intact respiratory system. PMID:7475389

  4. Surgical treatment of T3 lung cancer invading the chest wall.

    PubMed

    Beltrami, V; Bezzi, M; Illuminati, G; Forte, A; Angelici, A; Bertagni, A; Ciulli, A; Gallinaro, L; Lorenzotti, A; Montesano, G; Palumbo, P G; Prece, V

    1999-01-01

    Lung tumors invading the chest wall are classed as belonging to the T3 group and are considered potentially resectable. Their management, however, is controversial, and extrapleural resection, when possible, is preferred to en bloc resection which is regarded as a far more invasive and dangerous operation. Five year survival rates for completely resected cases range in the literature from 25 to 35%, but survival rates are much worse if lymph node metastases are present. These poor outcomes have prompted the development of combined surgical approaches: preoperative radiation therapy, with or without chemotherapy, has been used with an improvement in resectability rates, but only modest results in terms of median survival; in a number of case series, increased operative morbidity and mortality have been reported with this approach. The present report relates to 122 patients treated by en bloc (20 cases) or extrapleural (102 cases) resection, 31 of whom also received neoadjuvant treatment. The operative mortality was 4.6%. Median survival was 17 months after en bloc resection and 19 months after extrapleural resection. Though no statistically significant difference was found, extrapleural resection would appear to yield better results than the en bloc procedure. PMID:10742890

  5. Mesenchymal Hamartoma of Chest Wall in an Infant: Mimicking Persistent Pneumonia

    PubMed Central

    Singh, Amitabh; Pai, Gautham; Dawman, Lesa; Satapathy, Amit

    2015-01-01

    Mesenchymal Hamartoma of the chest wall (MHCW) is a very rare benign tumour. They are usually discovered in infancy. Spontaneous regression is known to occur in this benign condition. Management is surgical removal of mass if respiratory compromise is present. Conservative management is preferred modality in asymptomatic children as malignant transformation is not reported. Herein, we present a case of MHCW in a 5 month old infant presenting with acute respiratory distress with history of respiratory problem at 3 months of age. Child was suspected to have persistent pneumonia in view of radiological findings. Child’s respiratory distress improved with antibiotics and bronchodilators. Respiratory symptoms in MHCW are due to extrinsic compression of lung parenchyma. Present case had respiratory symptoms with persistent radiological findings leading to suspicion of persistent pneumonia. His respiratory symptoms and exacerbation on follow up was attributed to hyper reactive airway disease and MHCW was managed conservatively. The non-neoplastic nature, characteristic presentation, histopathology, imaging modality and management options of MHCW are discussed. PMID:26500976

  6. Chest-wall segmentation in automated 3D breast ultrasound images using thoracic volume classification

    NASA Astrophysics Data System (ADS)

    Tan, Tao; van Zelst, Jan; Zhang, Wei; Mann, Ritse M.; Platel, Bram; Karssemeijer, Nico

    2014-03-01

    Computer-aided detection (CAD) systems are expected to improve effectiveness and efficiency of radiologists in reading automated 3D breast ultrasound (ABUS) images. One challenging task on developing CAD is to reduce a large number of false positives. A large amount of false positives originate from acoustic shadowing caused by ribs. Therefore determining the location of the chestwall in ABUS is necessary in CAD systems to remove these false positives. Additionally it can be used as an anatomical landmark for inter- and intra-modal image registration. In this work, we extended our previous developed chestwall segmentation method that fits a cylinder to automated detected rib-surface points and we fit the cylinder model by minimizing a cost function which adopted a term of region cost computed from a thoracic volume classifier to improve segmentation accuracy. We examined the performance on a dataset of 52 images where our previous developed method fails. Using region-based cost, the average mean distance of the annotated points to the segmented chest wall decreased from 7.57±2.76 mm to 6.22±2.86 mm.art.

  7. Actinomycetoma of the chest wall attributed to Nocardia nova after reconstructive surgery.

    PubMed

    Antunes, Joana; Pacheco, David; Travassos, Rita; Sequeira, Hortênsia; Filipe, Paulo; Marques, Manuel Sacramento

    2012-01-01

    A 29-year-old man, presented with multiple ulcers, nodules, abscesses, fistulae, and atrophic scars, over the right chest wall. Six years prior, the patient had a car accident, which resulted in skin loss of the right arm, shoulder, thoracic wall. In addition, he suffered a supracondylar fracture; orthopedic surgery and skin grafts were required. Material discharging from sinus tracts was obtained for mycological and bacteriological studies. Direct microscopic examination revealed small white grains. Cultures on Sabouraud and Lowenstein-Jensen media isolated orange-white colonies suggestive of Nocardia. PCR assay identified Nocardia nova. Thoracic and right upper limb CT showed signs of chronic osteomyelitis. Treatment with imipenem/cilastatin for 8 weeks, followed by amoxicillin clavulanate for 6 months, resulted in healing of lesions and improvement in the patient's general health. Primary cutaneous nocardiosis remains a diagnostic challenge. Nocardia are soil-borne filamentous gram-positive bacteria. Identification of characteristic granules on examination of discharge smears from discharge or tissue biopsy is essential for diagnosing mycetoma. Because grain discharge is discontinuous, multiple clinical specimens should be submitted for microscopic examination and culture. Sulfonamides have been the mainstay of Nocardia actinomycetoma treatment. However, our patient's strain was resistant to Co-trimoxazole. Therefore, treatment with imipenem followed by amoxicillin clavulanate was favored, with good clinical and analytical response. PMID:22301041

  8. Dynamic 3D printed titanium copy prosthesis: a novel design for large chest wall resection and reconstruction

    PubMed Central

    Pérez Méndez, Itzell

    2016-01-01

    Due to high rates of complications, chest wall resection and reconstruction is a high risk procedure when large size of resection is required. Many different prosthetic materials have been used with similar results. Recently, thanks to the new advances in technology, personalized reconstruction have been possible with specific custom-made prosthesis. Nevertheless, they all generate certain amount of stiffness in thoracic motion because of his rigidity. In this report, we present a forward step in prosthesis design based on tridimensional titanium-printed technology. An exact copy of the resected chest wall was made, even endowing simulated sternochondral articulations, to achieve the most exact adaptation and best functional results, with a view to minimize postoperative complications. This novel design, may constitute an important step towards the improvement of the functional postoperative outcomes compared to the other prosthesis, on the hope, to reduce postoperative complications. PMID:27293863

  9. Primary chest wall abscess mimicking a breast tumor that occurred after blunt chest trauma: a case report.

    PubMed

    Yamaoka, Yusuke; Yamamura, Jun; Masuda, Norikazu; Yasojima, Hiroyuki; Mizutani, Makiko; Nakamori, Shoji; Kanazawa, Toru; Kuriyama, Keiko; Mano, Masayuki; Sekimoto, Mitsugu

    2014-01-01

    Primary chest wall abscess occurring after blunt chest trauma is rare. We present the case of a 50-year-old woman who presented with a swelling in her left breast. The patient had experienced blunt chest trauma 2 months back. Needle aspiration revealed pus formation in the patient's chest. Computed tomography revealed a mass in the lower region of the left mammary gland, with thickening of the parietal pleura and skin and fracture of the fifth rib under the abscess. Following antibiotic administration and irrigation of the affected region, surgical debridement was performed. During surgery, we found that the pectoralis major muscle at the level of the fifth rib was markedly damaged, although the necrotic tissue did not contact the mammary gland. We diagnosed the lesion as a chest wall abscess that occurred in response to blunt chest trauma. Her postoperative course was uneventful. There has been no recurrence for six months after surgery. PMID:24660001

  10. Dynamic 3D printed titanium copy prosthesis: a novel design for large chest wall resection and reconstruction.

    PubMed

    Aragón, Javier; Pérez Méndez, Itzell

    2016-06-01

    Due to high rates of complications, chest wall resection and reconstruction is a high risk procedure when large size of resection is required. Many different prosthetic materials have been used with similar results. Recently, thanks to the new advances in technology, personalized reconstruction have been possible with specific custom-made prosthesis. Nevertheless, they all generate certain amount of stiffness in thoracic motion because of his rigidity. In this report, we present a forward step in prosthesis design based on tridimensional titanium-printed technology. An exact copy of the resected chest wall was made, even endowing simulated sternochondral articulations, to achieve the most exact adaptation and best functional results, with a view to minimize postoperative complications. This novel design, may constitute an important step towards the improvement of the functional postoperative outcomes compared to the other prosthesis, on the hope, to reduce postoperative complications. PMID:27293863

  11. Evaluation of the safety of high-frequency chest wall oscillation (HFCWO) therapy in blunt thoracic trauma patients

    PubMed Central

    Anderson, Casandra A; Palmer, Cassandra A; Ney, Arthur L; Becker, Brian; Schaffel, Steven D; Quickel, Robert R

    2008-01-01

    Background Airway clearance is frequently needed by patients suffering from blunt chest wall trauma. High Frequency Chest Wall Oscillation (HFCWO) has been shown to be effective in helping to clear secretions from the lungs of patients with cystic fibrosis, bronchiectasis, asthma, primary ciliary dyskinesia, emphysema, COPD, and many others. Chest wall trauma patients are at increased risk for development of pulmonary complications related to airway clearance. These patients frequently have chest tubes, drains, catheters, etc. which could become dislodged during HFCWO. This prospective observational study was conducted to determine if HFCWO treatment, as provided by The Vest™ Airway Clearance System (Hill-Rom, Saint Paul, MN), was safe and well tolerated by these patients. Methods Twenty-five blunt thoracic trauma patients were entered into the study. These patients were consented. Each patient was prescribed 2, 15 minute HFCWO treatments per day using The Vest® Airway Clearance System (Hill-Rom, Inc., St Paul, MN). The Vest® system was set to a frequency of 10–12 Hz and a pressure of 2–3 (arbitrary unit). Physiological parameters were measured before, during, and after treatment. Patients were free to refuse or terminate a treatment early for any reason. Results No chest tubes, lines, drains or catheters were dislodged as a result of treatment. One patient with flail chest had a chest tube placed after one treatment due to increasing serous effusion. No treatments were missed and continued without further incident. Post treatment survey showed 76% experienced mild or no pain and more productive cough. Thirty days after discharge there were no deaths or hospital re-admissions. Conclusion This study suggests that HFCWO treatment is safe for trauma patients with lung and chest wall injuries. These findings support further work to demonstrate the airway clearance benefits of HFCWO treatment. PMID:18837992

  12. Concomitant surgical treatment of a chondrosarcoma of the chest wall and a desmoid tumor of the gastrointestinal tract

    PubMed Central

    Sadowski, Andrzej; Chruścicka, Iwona; Rak, Piotr; Ptach, Anna; Maliszewski, Daniel; Pęksa, Rafał; Haponiuk, Ireneusz

    2015-01-01

    The co-existence of a chondrosarcoma of the chest wall and a desmoid tumor in the gastrointestinal tract is rare. In both Polish and global literature, cases of chest wall chondrosarcomas are presented in the form of case reports. Desmoids of the gastrointestinal tract are more common; notwithstanding, their incidence in Europe is estimated at approximately 2 cases per 1 million inhabitants per year. We present the case of a 62-year-old female patient who suffered from both a chest wall chondrosarcoma and a desmoid tumor of the intestine; both neoplasms were operated on simultaneously. The former tumor was located in the region of the right costal margin, whereas the latter was located in the mesojejunum. The surgery was performed with two independent surgical incisions. The postoperative period was uneventful. The case is noteworthy in view of the extremely rare synchronous occurrence of the described tumors and due to the fact that any such operation requires an individualized surgical approach. PMID:26336503

  13. Chest wall reconstruction in a canine model using polydioxanone mesh, demineralized bone matrix and bone marrow stromal cells.

    PubMed

    Tang, Hua; Xu, Zhifei; Qin, Xiong; Wu, Bin; Wu, Lihui; Zhao, XueWei; Li, Yulin

    2009-07-01

    Extensive chest wall defect reconstruction remains a challenging problem for surgeons. In the past several years, little progress has been made in this area. In this study, a biodegradable polydioxanone (PDO) mesh and demineralized bone matrix (DBM) seeded with osteogenically induced bone marrow stromal cells (BMSCs) were used to reconstruct a 6 cm x 5.5 cm chest wall defect. Four experimental groups were evaluated (n=6 per group): polydioxanone (PDO) mesh/DBMs/BMSCs group, polydioxanone (PDO) mesh/DBMs group, polydioxanone (PDO) mesh group, and a blank group (no materials) in a canine model. All the animals survived except those in the blank group. In all groups receiving biomaterial implants, the polydioxanone (PDO) mesh completely degraded at 24 weeks and was replaced by fibrous tissue with thickness close to that of the normal intercostal tissue (P>0.05). In the polydioxanone (PDO) mesh/DBMs/BMSCs group, new bone formation and bone-union were observed by radiographic and histological examination. More importantly, the reconstructed rib could maintain its original radian and achieve satisfactory biomechanics close to normal ribs in terms of bending stress (P>0.05). However, in the other two groups, fibrous tissue was observed in the defect and junctions, and the reconstructed ribs were easily distorted under an outer force. Based on these results, a surgical approach utilizing biodegradable polydioxanone (PDO) mesh in combination with DBMs and BMSCs could repair the chest wall defect not only in function but also in structure. PMID:19233465

  14. 3D analysis of the chest wall motion for monitoring late-onset Pompe disease patients.

    PubMed

    Meric, Henri; Falaize, Line; Pradon, Didier; Orlikowski, David; Prigent, Hélène; Lofaso, Frédéric

    2016-02-01

    Late-onset Pompe disease, for which enzyme replacement therapy is available, induces progressive diaphragmatic weakness. Monitoring diaphragmatic function is therefore crucial but is hindered by the need to insert esophageal and gastric probes. Vital capacity (VC), inspiratory capacity, maximal inspiratory pressure, and sniff nasal pressure are noninvasive measurements but reflect only global inspiratory-muscle function. Diaphragmatic function may be assessable noninvasively based on abdominal contribution to breathing and abdominal volume change during the VC maneuver (AVC-VC), obtained by 3-dimensional chest-wall analysis. In 11 patients, we assessed the relationships between the above-listed noninvasive variables and the invasively measured Gilbert index reflecting the diaphragmatic contribution to breathing (ratio of gastric pressure over transdiaphragmatic pressure swings during spontaneous breathing). Only abdominal contribution to breathing and AVC-VC correlated significantly with the Gilbert index (R = 0.977, P = 0.0001; and R = 0.944, P = 0.001 respectively). AVC-VC correlated significantly with transdiaphragmatic pressure swing during the sniff maneuver (R = 0.743, P = 0.0009) and with phrenic magnetic stimulation (R = 0.610, P = 0.046). Repeat testing 1 year later in the first 6 patients showed concordant changes in abdominal contribution to breathing, Gilbert index, and VC. Abdominal contribution to breathing and AVC-VC are reliable and noninvasive indices of diaphragmatic function in Pompe disease, and therefore hold promise as clinical monitoring tools. PMID:26711305

  15. Lung and chest wall mechanics in patients with acquired immunodeficiency syndrome and severe Pneumocystis carinii pneumonia.

    PubMed

    D'Angelo, E; Calderini, E; Robatto, F M; Puccio, P; Milic-Emili, J

    1997-10-01

    The aim of this study was to assess the mechanical characteristics of the respiratory system in patients with acquired immune deficiency syndrome (AIDS) and acute respiratory distress syndrome (ARDS) caused by Pneumocystis carinii pneumonia (PCP). In 12 mechanically ventilated patients, total respiratory system mechanics was assessed using the technique of rapid airway occlusion during constant flow inflation, and was partitioned into lung and chest wall components using the oesophageal balloon technique. We measured interrupter resistance (Rint), which mainly reflects airway resistance, additional resistance (deltaR) due to viscoelastic behaviour and time constant inequalities, and static elastance (Est). In addition, the static inflation volume-pressure (V-P) curve was assessed. In eight patients, computed tomography scans were performed within 2 days of the assessment of respiratory mechanics. Compared to values reported in the literature for normal subjects, Est and deltaR were markedly increased in AIDS patients with PCP, whilst Rint exhibited a relatively smaller increase. These changes, which involved only the lung and airways, were mainly due to the reduction of ventilated lung units, but additional factors were involved to cause independent modifications of lung stiffness, airway calibre, and viscoelastic properties. The changes in Rint, deltaR, and Est were similar to those observed in other studies on patients with ARDS of different aetiologies. At variance with common observations in the latter patients, none of the AIDS patients with PCP exhibited an inflection point on the static inflation V-P curve, suggesting little or no alveolar recruitment during lung inflation. This finding could be related to the distinctive histopathology of Pneumocystis carinii pneumonia. Indeed, computed tomography revealed homogeneous diffuse interstitial and alveolar infiltration rather than the dense, dependent opacities observed in other studies on acute respiratory

  16. Chest Wall Toxicity After Stereotactic Body Radiotherapy for Malignant Lesions of the Lung and Liver

    SciTech Connect

    Andolino, David L.; Forquer, Jeffrey A.; Henderson, Mark A.; Barriger, Robert B.; Shapiro, Ronald H.; Brabham, Jeffrey G.; Johnstone, Peter A.S.; Cardenes, Higinia R.; Fakiris, Achilles J.

    2011-07-01

    Purpose: To quantify the frequency of rib fracture and chest wall (CW) pain and identify the dose-volume parameters that predict CW toxicity after stereotactic body radiotherapy (SBRT). Methods and Materials: The records of patients treated with SBRT between 2000 and 2008 were reviewed, and toxicity was scored according to Common Terminology Criteria for Adverse Events v3.0 for pain and rib fracture. Dosimetric data for CW and rib were analyzed and related to the frequency of toxicity. The risks of CW toxicity were then further characterized according to the median effective concentration (EC{sub 50}) dose-response model. Results: A total of 347 lesions were treated with a median follow-up of 19 months. Frequency of Grade I and higher CW pain and/or fracture for CW vs. non-CW lesions was 21% vs. 4%, respectively (p < 0.0001). A dose of 50 Gy was the cutoff for maximum dose (Dmax) to CW and rib above which there was a significant increase in the frequency of any grade pain and fracture (p = 0.03 and p = 0.025, respectively). Volume of CW receiving 15 Gy - 40 Gy was highly predictive of toxicity (R{sup 2} > 0.9). According to the EC{sub 50} model, 5 cc and 15 cc of CW receiving 40 Gy predict a 10% and 30% risk of CW toxicity, respectively. Conclusion: Adequate tumor coverage remains the primary objective when treating lung or liver lesions with SBRT. To minimize toxicity when treating lesions in close proximity to the CW, Dmax of the CW and/or ribs should remain <50 Gy, and <5 cc of CW should receive {>=}40 Gy.

  17. Ventilation by high-frequency chest wall compression in dogs with normal lungs.

    PubMed

    Zidulka, A; Gross, D; Minami, H; Vartian, V; Chang, H K

    1983-06-01

    In 6 anesthetized and paralyzed supine dogs, ventilation by high-frequency chest wall compression (HFCWC) was accomplished by a piston pump rapidly oscillating the pressure in a modified double blood pressure cuff wrapped around the lower thorax. Testing applied frequencies at 3, 5, 8, and 11 Hz, applied peak cuff pressures ranged from 30 to 230 cmH2O. This produced swings of esophageal pressure as high as 18 cmH2O and peak oscillatory air flow ranging from 0.7 to 1.6 L/s. Oscillatory tidal volume declined with increasing frequency and ranged from a mean of 61 to 45 ml. After 30 min of applied HFCWC, arterial blood gas determinations revealed a mean PaCO2 of 29.3 mmHg at 5 Hz, 35 mmHg at 3 Hz, 36 mmHg at 8 Hz, and 51 mmHg at 11 Hz. Mean PaO2 improved from ventilator control values at 3 Hz, remained unchanged at 5 and 8 Hz, and declined at 11 Hz. In 2 dogs breathing spontaneously, HFCWC applied at 5 and 11 Hz resulted in a reduction in spontaneous minute ventilation, mainly by a reduction in spontaneous tidal volume, whereas arterial blood gas values changed slightly. One dog ceased to breath spontaneously within 5 min of application of HFCWC as the PaCO2 fell below control values. We conclude that in dogs with normal lungs, HFCWC may assist spontaneous ventilation. In paralyzed dogs, HFCWC may be of sufficient magnitude to cause hyperventilation. PMID:6407373

  18. Revision breast and chest wall reconstruction in Poland and pectus excavatum following implant complication using free deep inferior epigastric perforator flap

    PubMed Central

    Dionyssiou, Dimitrios; Demiri, Efterpi; Batsis, Georgios; Pavlidis, Leonidas

    2015-01-01

    This study aims to present the case of a female patient with Poland's syndrome and pectus excavatum deformity who underwent breast and chest wall reconstruction with a pre-shaped free deep inferior epigastric perforator flap. A 57-year-old female patient with Poland's syndrome and pectus excavatum presented with a Baker III capsular contracture following a previously performed implant-based right breast reconstruction. After a chest and abdominal CT angiography, she was staged as 2A1 chest wall deformity according to Park's classification and underwent implant removal and capsulectomy, followed by a pre-shaped free abdominal flap transfer, providing both breast reconstruction and chest wall deformity correction in a single stage operation. Post-operative course was uneventful, and the aesthetic result remains highly satisfactory 24 months after surgery. Deep inferior epigastric free flap represents an interesting reconstructive solution when treating Poland's syndrome female patients with chest wall and breast deformities. PMID:25991894

  19. Recurrent cystosarcoma phylloides of breast: extensive full-thickness excision of chest wall with immediate repair using steel mesh and a latissimus dorsi myocutaneous flap.

    PubMed

    Mindikoğlu, A N; Aktan, K

    1983-10-01

    The case of a young woman with a massive recurrent cystosarcoma phylloides of the breast is presented in whom a full thickness excision of the chest wall was carried out en bloc together with four ribs. The large full-thickness defect of the chest wall was reconstructed with stainless steel mesh and covered by a latissimus dorsi myocutaneous flap. The management of post-operative paradoxical movement is also described. PMID:6313105

  20. The gender-specific chest wall thickness prediction equations for routine measurements of 239Pu and 241Am within the lungs using HPGe detectors.

    PubMed

    Vickers, L R

    1996-03-01

    The current chest wall thickness prediction equation is not applicable to use in routine lung counting measurements for detection of low energy photons (17--60 keV) within the lungs of male and female subjects. The current chest wall thickness prediction equation was derived for the NaI-CsI "phoswich" detection system, which is not the routine detection system in use; the subject position was supine, which is not the routine position; the equation did not account for the intercostal tissue thicknesses of muscle and adipose which significantly attenuate low energy photons (17--60keV); it was derived from male subjects only and is used to predict the chest wall thickness of female subjects for whom it is not applicable. The current chest wall thickness prediction equation yields unacceptable percent errors in the HPGe detection efficiency calibration for 239Pu and 241Am (17- and 59.5-keV photons, respectively) relative to the gender-specific HPGe chest wall thickness prediction equations of this paper (+284% to --73% for 239Pu; (+)42% to --39% for 241Am). As a result, use of the current chest wall thickness prediction equation yields unacceptable percent errors (proportional in magnitude to the percent errors in the detection efficiency calibration) in the calculation of the minimum detectable activity (Bq) or in an initial assessment of a radioactive contamination exposure detected by a routine lung count measurement. PMID:8609026

  1. Thermal characteristics of thermobrachytherapy surface applicators for treating chest wall recurrence

    NASA Astrophysics Data System (ADS)

    Arunachalam, K.; Maccarini, P. F.; Craciunescu, O. I.; Schlorff, J. L.; Stauffer, P. R.

    2010-04-01

    The aim of this study was to investigate temperature and thermal dose distributions of thermobrachytherapy surface applicators (TBSAs) developed for concurrent or sequential high dose rate (HDR) brachytherapy and microwave hyperthermia treatment of chest wall recurrence and other superficial diseases. A steady-state thermodynamics model coupled with the fluid dynamics of a water bolus and electromagnetic radiation of the hyperthermia applicator is used to characterize the temperature distributions achievable with TBSAs in an elliptical phantom model of the human torso. Power deposited by 915 MHz conformal microwave array (CMA) applicators is used to assess the specific absorption rate (SAR) distributions of rectangular (500 cm2) and L-shaped (875 cm2) TBSAs. The SAR distribution in tissue and fluid flow distribution inside the dual-input dual-output (DIDO) water bolus are coupled to solve the steady-state temperature and thermal dose distributions of the rectangular TBSA (R-TBSA) for superficial tumor targets extending 10-15 mm beneath the skin surface. Thermal simulations are carried out for a range of bolus inlet temperature (Tb = 38-43 °C), water flow rate (Qb = 2-4 L min-1) and tumor blood perfusion (ωb = 2-5 kg m-3 s-1) to characterize their influence on thermal dosimetry. Steady-state SAR patterns of the R- and L-TBSA demonstrate the ability to produce conformal and localized power deposition inside the tumor target sparing surrounding normal tissues and nearby critical organs. Acceptably low variation in tissue surface cooling and surface temperature homogeneity was observed for the new DIDO bolus at a 2 L min-1 water flow rate. Temperature depth profiles and thermal dose volume histograms indicate bolus inlet temperature (Tb) to be the most influential factor on thermal dosimetry. A 42 °C water bolus was observed to be the optimal choice for superficial tumors extending 10-15 mm from the surface even under significant blood perfusion. Lower bolus

  2. Higher Chest Wall Dose Results in Improved Locoregional Outcome in Patients Receiving Postmastectomy Radiation

    SciTech Connect

    Panoff, Joseph E.; Takita, Cristiane; Hurley, Judith; Reis, Isildinha M.; Zhao, Wei; Rodgers, Steven E.; Gunaseelan, Vijayalakshmi; Wright, Jean L.

    2012-03-01

    Purpose: Randomized trials demonstrating decreased locoregional recurrence (LRR) and improved overall survival (OS) in women receiving postmastectomy radiation therapy (PMRT) used up to 50 Gy to the chest wall (CW), but in practice, many centers boost the CW dose to {>=}60 Gy, despite lack of data supporting this approach. We evaluated the relationship between CW dose and clinical outcome. Methods and Materials: We retrospectively reviewed medical records of 582 consecutively treated patients who received PMRT between January 1999 and December 2009. We collected data on patient, disease, treatment characteristics, and outcomes of LRR, progression-free survival (PFS) and OS. Results: Median follow-up from the date of diagnosis was 44.7 months. The cumulative 5-year incidence of LRR as first site of failure was 6.2%. CW dose for 7% (43 patients) was {<=}50.4 Gy (range, 41.4-50.4 Gy) and 93% received >50.4 Gy (range, 52.4-74.4 Gy). A CW dose of >50.4 Gy vs. {<=}50.4 Gy was associated with lower incidence of LRR, a 60-month rate of 5.7% (95% confidence interval [CI], 3.7-8.2) vs. 12.7% (95% CI, 4.5-25.3; p = 0.054). Multivariate hazard ratio (HR) for LRR controlling for race, receptor status, and stage was 2.62 (95% CI, 1.02-7.13; p = 0.042). All LRR in the low-dose group occurred in patients receiving 50 to 50.4 Gy. Lower CW dose was associated with worse PFS (multivariate HR, 2.73; 95% CI, 1.64-4.56; p < 0.001) and OS (multivariate HR, 3.88; 95% CI, 2.16-6.99; p < 0.001). Conclusions: The addition of a CW boost above 50.4 Gy resulted in improved locoregional control and survival in this cohort patients treated with PMRT for stage II-III breast cancer. The addition of a CW boost to standard-dose PMRT is likely to benefit selected high-risk patients. The optimal technique, target volume, and patient selection criteria are unknown. The use of a CW boost should be studied prospectively, as has been done in the setting of breast conservation.

  3. Evaluating Proton Stereotactic Body Radiotherapy to Reduce Chest Wall Dose in the Treatment of Lung Cancer

    PubMed Central

    Welsh, James; Nguyen, Ngoc; Palmer, Matt; Allen, Pamela K.; Paolini, Michael; Liao, Zhongxing; Bluett, Jaques; Mohan, Radhe; Gomez, Daniel; Cox, James D.; Komaki, Ritsuko; Chang, Joe Y.

    2014-01-01

    Purpose Stereotactic body radiotherapy (SBRT) can produce excellent local control of several types of solid tumor; however, toxicity to nearby critical structures is a concern. We found previously that in SBRT for lung cancer, the chest wall (CW) volume receiving 20, 30, or 40 Gy (V20, V30, or V40) was linked with the development of neuropathy. Here we sought to determine whether the dosimetric advantages of protons could produce lower CW doses than traditional photon-based SBRT. Methods We searched an institutional database to identify patients treated with photon SBRT for lung cancer with tumors within <2.5 cm of the CW. We found 260 cases; of these chronic grade ≥2 CW pain was identified in 23 patients. We then selected 10 representative patients from this group and generated proton SBRT treatment plans, using the identical dose of 50 Gy in 4 fractions, and assessed potential differences in CW dose between the two plans. Results The proton SBRT plans reduced the CW doses at all dose levels measured. The median CW V was 364.0 cm320 for photons and 160.0 cm3 for protons (P<0.0001); V30 was 144.6 cm3 for photons vs. 77.0 cm3 for protons (P=0.0012); V was 93.9 cm335 for photons vs. 57.9 cm3 for protons (P=0.005); V40 was 66.5 cm3 for photons vs. 45.4 cm3 for protons (P=0.0112); and mean lung dose was 5.9 Gy for photons vs. 3.8 Gy for protons (P=0.0001). Coverage of the planning target volume was comparable between the two sets of plans (96.4% for photons and 97% for protons). Conclusions From a dosimetric standpoint, proton SBRT can achieve the same coverage of the PTV while significantly reducing the dose to the CW and lung relative to photon SBRT and therefore may be beneficial for the treatment of lesions close to critical structures. PMID:24200220

  4. Evaluating proton stereotactic body radiotherapy to reduce chest wall dose in the treatment of lung cancer

    SciTech Connect

    Welsh, James; Amini, Arya; Ciura, Katherine; Nguyen, Ngoc; Palmer, Matt; Soh, Hendrick; Allen, Pamela K.; Paolini, Michael; Liao, Zhongxing; Bluett, Jaques; Mohan, Radhe; Gomez, Daniel; Cox, James D.; Komaki, Ritsuko; Chang, Joe Y.

    2013-01-01

    Stereotactic body radiotherapy (SBRT) can produce excellent local control of several types of solid tumor; however, toxicity to nearby critical structures is a concern. We found previously that in SBRT for lung cancer, the chest wall (CW) volume receiving 20, 30, or 40 Gy (V{sub 20}, V{sub 30}, or V{sub 40}) was linked with the development of neuropathy. Here we sought to determine whether the dosimetric advantages of protons could produce lower CW doses than traditional photon-based SBRT. We searched an institutional database to identify patients treated with photon SBRT for lung cancer with tumors within < 2.5 cm of the CW. We found 260 cases; of these, chronic grade ≥ 2 CW pain was identified in 23 patients. We then selected 10 representative patients from this group and generated proton SBRT treatment plans, using the identical dose of 50 Gy in 4 fractions, and assessed potential differences in CW dose between the 2 plans. The proton SBRT plans reduced the CW doses at all dose levels measured. The median CW V{sub 20} was 364.0 cm{sup 3} and 160.0 cm{sup 3} (p < 0.0001), V{sub 30} was 144.6 cm{sup 3}vs 77.0 cm{sup 3} (p = 0.0012), V{sub 35} was 93.9 cm{sup 3}vs 57.9 cm{sup 3} (p = 0.005), V{sub 40} was 66.5 cm{sup 3}vs 45.4 cm{sup 3} (p = 0.0112), and mean lung dose was 5.9 Gy vs 3.8 Gy (p = 0.0001) for photons and protons, respectively. Coverage of the planning target volume (PTV) was comparable between the 2 sets of plans (96.4% for photons and 97% for protons). From a dosimetric standpoint, proton SBRT can achieve the same coverage of the PTV while significantly reducing the dose to the CW and lung relative to photon SBRT and therefore may be beneficial for the treatment of lesions closer to critical structures.

  5. Development and validation of a clinical prediction rule for chest wall syndrome in primary care

    PubMed Central

    2012-01-01

    Background Chest wall syndrome (CWS), the main cause of chest pain in primary care practice, is most often an exclusion diagnosis. We developed and evaluated a clinical prediction rule for CWS. Methods Data from a multicenter clinical cohort of consecutive primary care patients with chest pain were used (59 general practitioners, 672 patients). A final diagnosis was determined after 12 months of follow-up. We used the literature and bivariate analyses to identify candidate predictors, and multivariate logistic regression was used to develop a clinical prediction rule for CWS. We used data from a German cohort (n = 1212) for external validation. Results From bivariate analyses, we identified six variables characterizing CWS: thoracic pain (neither retrosternal nor oppressive), stabbing, well localized pain, no history of coronary heart disease, absence of general practitioner’s concern, and pain reproducible by palpation. This last variable accounted for 2 points in the clinical prediction rule, the others for 1 point each; the total score ranged from 0 to 7 points. The area under the receiver operating characteristic (ROC) curve was 0.80 (95% confidence interval 0.76-0.83) in the derivation cohort (specificity: 89%; sensitivity: 45%; cut-off set at 6 points). Among all patients presenting CWS (n = 284), 71% (n = 201) had a pain reproducible by palpation and 45% (n = 127) were correctly diagnosed. For a subset (n = 43) of these correctly classified CWS patients, 65 additional investigations (30 electrocardiograms, 16 thoracic radiographies, 10 laboratory tests, eight specialist referrals, one thoracic computed tomography) had been performed to achieve diagnosis. False positives (n = 41) included three patients with stable angina (1.8% of all positives). External validation revealed the ROC curve to be 0.76 (95% confidence interval 0.73-0.79) with a sensitivity of 22% and a specificity of 93%. Conclusions This CWS score offers a useful

  6. A Comparison of Skin and Chest Wall Dose Delivered With Multicatheter, Contura Multilumen Balloon, and MammoSite Breast Brachytherapy

    SciTech Connect

    Cuttino, Laurie W.; Todor, Dorin; Rosu, Mihaela; Arthur, Douglas W.

    2011-01-01

    Purpose: Skin and chest wall doses have been correlated with toxicity in patients treated with breast brachytherapy . This investigation compared the ability to control skin and chest wall doses between patients treated with multicatheter (MC), Contura multilumen balloon (CMLB), and MammoSite (MS) brachytherapy. Methods and Materials: 43 patients treated with the MC technique, 45 patients treated with the CMLB, and 83 patients treated with the MS were reviewed. The maximum doses delivered to the skin and chest wall were calculated for all patients. Results: The mean maximum skin doses for the MC, CMLB, and MS were 2.3 Gy (67% of prescription dose), 2.8 Gy (82% of prescription dose), and 3.2 Gy per fraction (94% of prescription dose), respectively. Although the skin distances were similar (p = 0.23) for the two balloon techniques, the mean skin dose with the CMLB was significantly lower than with the MS (p = 0.05). The mean maximum rib doses for the MC, CMLB, and MS were 2.3 Gy (67% of prescription dose), 2.8 Gy (82% of prescription dose), and 3.6 Gy per fraction (105% of prescription dose), respectively. Again, the mean rib dose with the CMLB was significantly lower than with the MS (p = 0.002). Conclusion: The MC and CMLB techniques are associated with significantly lower mean skin and rib doses than is the MS. Treatment with the MS was associated with significantly more patients receiving doses to the skin or rib in excess of 125% of the prescription. Treatment with the CMLB may prove to yield less normal tissue toxicity than treatment with the MS.

  7. Conformal Radiotherapy Facilitates the Delivery of Concurrent Chemotherapy and Radiotherapy: A Case of Primitive Neuroectodermal Tumour of the Chest Wall

    PubMed Central

    Twyman, N.; Earl, H. M.; Burnet, N. G.

    2000-01-01

    We illustrate the principle of conformal radiotherapy by discussing the case of a patient with a primitive neuroectodermal tumour of the chest wall. Recent advances in radiotherapy planning enable precise localization of the planning target volume (PTV) and normal organs at risk of irradiation. Customized blocks are subsequently designed to produce a treatment field that ‘conforms’ to the PTV. The use of conformal radiotherapy (CRT) in this case facilitated the delivery of concurrent chemotherapy and radiotherapy by significantly reducing the volume of red marrow irradiated.The lack of acute and late toxicities was attributed to optimal exclusion of normal tissues from the treatment field, made possible by CRT. PMID:18521292

  8. A study of the first heart sound spectra in normal anesthetized cats: possible origins and chest wall influences.

    PubMed

    Fazzalari, N L; Mazumdar, J; Ghista, D N; Allen, D G; de Bruin, H

    1984-01-01

    Heart sound recordings were taken from cats. The heart sounds were recorded directly from the chest wall and through an esophageal tube. The phono transducer and the esophageal tube were both placed over the base of the heart. Ultrasound M-mode, or motion-mode, recordings were taken to study the mitral valve dynamics. After analogue to digital conversion, electrocardiogram gated first heart sounds of each phono record were analyzed by the fast Fourier transform to obtain a frequency spectrum. Relative energies in 15 Hz bandwidths up to 150 Hz were correlated with the mitral valve closing velocity of the anterior mitral leaflet, obtained from the M-mode echocardiograms. The closing velocity correlated best with the energy in the 30-45 Hz bandwidth and 60-75 Hz bandwidth for the externally and internally monitored phonocardiogram respectively. The chest wall acted as a low pass filter, that is, the wall favoured the transmission of low frequencies and the energy transmitted decreased as wall thickness increased. PMID:6713253

  9. Levofloxacin decreased chest wall mechanical inhomogeneities and airway and vascular remodeling in rats with induced hepatopulmonary syndrome.

    PubMed

    Gaio, Eduardo; Amado, Veronica; Rangel, Leonardo; Huang, Wilson; Storck, Rodrigo; Melo-Silva, César Augusto

    2013-12-01

    The administration of antibiotics decreases bacterial translocation, reduces the activity of nitric oxide synthase and improves the gas exchange of hepatopulmonary syndrome (HPS) in rats. We hypothesized that levofloxacin could reduce HPS-induced respiratory mechanical inhomogeneities and airway and pulmonary vascular remodeling. We assessed the respiratory mechanical properties and lung tissue structure in 24 rats assigned to the control, HPS (eHPS) and HPS+levofloxacin (eHPS+L) groups. The administration of levofloxacin reduced the HPS-induced chest wall but not the lung mechanical inhomogeneities. The eHPS airway proportion of elastic fibers increased 20% but was similar between the control and eHPS+L groups. The eHPS vascular collagen increased 25% in eHPS but was similar between the control and eHPS+L groups. Compared to the control group, the vascular proportion of elastic fibers of the eHPS and eHPS+L groups increased by 60% and 16%, respectively. The administration of levofloxacin decreased the HPS-induced chest wall mechanical inhomogeneities and airway and vascular remodeling. PMID:23994178

  10. Retrospective case series analysing the clinical data and treatment options of patients with a tubercular abscess of the chest wall

    PubMed Central

    Tanaka, Satona; Aoki, Minoru; Nakanishi, Takao; Otake, Yosuke; Matsumoto, Masataka; Sakurai, Toshiyasu; Tada, Kimihide; Ikeda, Akihiko

    2012-01-01

    The tubercular abscess of the chest wall remains one of the differential diagnoses of a chest wall tumour, and the management strategy is controversial. We reviewed the medical records of 22 patients treated at our institution. Two patients were managed by antitubercular medications alone; eight patients were managed by medication and open drainage. Five patients underwent open drainage with subsequent radical surgery at a constant interval of time, and the mean duration between open drainage and radical surgery was 9.8 weeks (range, 3–12). Seven patients underwent radical surgery without prior open drainage. Five patients required rib resections, and curettage of infected pleural peel was necessary in 5 patients. Antitubercular drugs were administered basically for more than 6 months regardless of surgical management, including for more than 1 month prior to radical surgery. Postoperative empyema was seen in 1 patient after radical surgery. The mean follow-up duration was 32.8 months (range, 3–100), and there was no recurrence. Complete resection of the tubercular abscess with sufficient antitubercular therapy resulted in a satisfactory outcome. Antitubercular therapy with or without open drainage can be a viable choice. PMID:22184463

  11. Acute effects of different inspiratory efforts on ventilatory pattern and chest wall compartmental distribution in elderly women.

    PubMed

    Muniz de Souza, Helga; Rocha, Taciano; Campos, Shirley Lima; Brandão, Daniella Cunha; Fink, James B; Aliverti, Andrea; de Andrade, Armele Dornelas

    2016-06-15

    It is not completely described how aging affect ventilatory kinematics and what are the mechanisms adopted by the elderly population to overcome these structural modifications. Given this, the aim was to evaluate the acute effects of different inspiratory efforts on ventilatory pattern and chest wall compartmental distribution in elderly women. Variables assessed included: tidal volume (Vt), total chest wall volume (Vcw), pulmonary rib cage (Vrcp%), abdominal rib cage (Vrca%) and abdominal compartment (Vab%) relative contributions to tidal volume. These variables were assessed during quiet breathing, maximal inspiratory pressure maneuver (MIP), and moderate inspiratory resistance (MIR; i.e., 40% of MIP). 22 young women (age: 23.9±2.5 years) and 22 elderly women (age: 68.2±5.0 years) participated to this study. It was possible to show that during quiet breathing, Vab% was predominant in elderly (p<0.001), in young, however, Vab% was similar to Vrcp% (p=0.095). During MIR, Vrcp% was predominant in young (p<0.001) and comparable to Vab% in elderly (p=0.249). When MIP was imposed, both groups presented a predominance of Vrcp%. In conclusion, there are differences in abdominal kinematics between young and elderly women during different inspiratory efforts. In elderly, during moderate inspiratory resistance, the pattern is beneficial, deep, and slow. Although, during maximal inspiratory resistance, the ventilatory pattern seems to predict imminent muscle fatigue. PMID:26900004

  12. Statistical methods for analysis of coordination of chest wall motion using optical reflectance imaging of multiple markers

    NASA Astrophysics Data System (ADS)

    Kenyon, C. M.; Ghezzo, R. H.; Cala, S. J.; Ferrigno, Giancarlo; Pedotti, Antonio; Macklem, P. T.; Rochester, D. F.

    1994-07-01

    To analyze coordination of chest wall motion we have used principle component analysis (PCA) and multiple regression analysis (MRA) with respect to spirometry on the displacements of 93 optical reflective markers placed upon the chest wall (CW). Each marker is tracked at 10 Hz with an accuracy of 0.2 mm in each spatial dimension using the ELITE system (IEEE Trans. Biomed. Eng. 11:943-949, 1985). PCA enables the degree of linear coordination between all of the markers to be assessed using the eigenvectors and eigenvalues of the covariance of the matrix of marker displacements in each dimension against time. Thus the number of linear degrees of freedom (DOF) which contribute more than a particular amount to the total variance can be determined and analyzed. MRA with respect to spirometrically measured lung volume changes enables identification of the CW points whose movement correlates best with lung volume. We have used this analysis to compare a quiet breathing sequence with one where tidal volume was increased fourfold involuntarily and show that the number of DOF with eigenvalues accounting for >5% of the covariance increased from 2 to 3. Also the point whose movement correlated best with lung volume changed from halfway down the lower costal margin to a more lateral point at the level of the bottom of the sternum. This quantification of CW coordination may be useful in analysis and staging of many respiratory disorders and is applicable to any nonrigid body motion where points can be tracked.

  13. Uncertainty induced by chest wall thickness assessment methods on lung activity estimation for plutonium and americium: a large population-based study.

    PubMed

    Broggio, D; Lechaftois, X; Franck, D

    2015-03-01

    In vivo lung counting aims at assessing the retained activity in the lungs. The calibration factor relating the measured counts to the worker's specific retained lung activity can be obtained by several means and strongly depends on the chest wall thickness. Here we compare, for 374 male nuclear workers, the activity assessed with a reference protocol, where the material equivalent chest wall thickness is known from ultrasound measurements, with two other protocols. The counting system is an array of four germanium detectors.It is found that non site-specific equations for the assessment of the chest wall thickness induce large biases in the assessment of activity. For plutonium isotopes or (241)Am the proportion of workers for whom the retained activity is within ± 10% of the reference one is smaller than 10%.The use of site-specific equations raises this proportion to 20% and 58% for plutonium and (241)Am, respectively.Finally, for the studied population, when site-specific equations are used for the chest wall thickness, the standard uncertainties for the lung activity are 42% and 12.5%, for plutonium and (241)Am, respectively. Due to the relatively large size of the studied population, these values are a relatively robust estimate of the uncertainties due to the assessment of the chest wall thickness for the current practice at this site. PMID:25517347

  14. [Reconstruction of the anterior chest wall by a sandwich-type combination of a synthetic support and a muscle flap from the latissimus dorsi. Apropos of a case].

    PubMed

    Lanfrey, E; Grolleau, J L; Glock, Y; Chavoin, J P; Costagliola, M

    1996-04-01

    Reconstruction of the chest wall after balistic or other trauma requires good and muscle cover and creation of a new, stable and airtight wall. The authors present a case of balistic trauma of the right anterolateral chest wall which was urgently debrided and subsequently reconstructed by sandwich combination of a latissimus dorsi muscle flap and synthetic material composed of a sheet of PTFE and creation of two methylmethylacrylate ribs. The advantage of this technique is that it avoids the use of autologous tissue from an already weakened chest wall and confers a new chest stability in several sites corresponding to the wall defect with easily available and easy-to-use materials. PMID:8761064

  15. Cutaneous reinnervation of the rectus abdominis musculocutaneous flap after chest wall reconstruction: development of herpes zoster in the transplanted musculocutaneous flap.

    PubMed

    Tomita, K; Inoue, K

    1998-08-01

    We report a patient in whom herpes zoster developed in the transplanted rectus abdominis musculocutaneous flap 14 months after a chest wall reconstruction for recurrent breast cancer. Based on the distribution of the varicella zoster virus spreading along the sensory nerve fibers, we concluded that the virus spread along the reinnervated sensory nerves from the dorsal ganglia, through the intercostal nerves, and into the flap skin. It is suggested that this finding demonstrates the pathway of reinnervation into the transferred musculocutaneous flap on the chest wall. PMID:9718154

  16. [The use of high-frequency chest wall oscillation for the combined treatment of the children presenting with mucoviscidosis].

    PubMed

    Khan, M A; Lian, N A; Mikitchenko, N A

    2014-01-01

    Mucoviscidosis is a hereditary disease characterized by the severe clinical course which requires its continuous management by means of appropriate therapeutic and rehabilitative modalities. The objective of the present study was to develop the scientifically grounded rationale for the application of vibration and compression impacts with the use of The Vest clearance system for the clearance of the airways in 30 children at the age varying from 5 to 17 years presenting with mucoviscidosis. The results of the study suggest high effectiveness of high-frequency oscillation of the chest wall in such patients. Moreover, the new data have been obtained illustrating the beneficial influence of this therapeutic modality on the clinical symptoms of the disease, characteristics of the external respiration function, and results of pulseoxymetry. PMID:25087417

  17. Dynamics of chest wall volume regulation during constant work rate exercise in patients with chronic obstructive pulmonary disease

    PubMed Central

    Takara, L.S.; Cunha, T.M.; Barbosa, P.; Rodrigues, M.K.; Oliveira, M.F.; Nery, L.E.; Neder, J.A.

    2012-01-01

    This study evaluated the dynamic behavior of total and compartmental chest wall volumes [(VCW) = rib cage (VRC) + abdomen (VAB)] as measured breath-by-breath by optoelectronic plethysmography during constant-load exercise in patients with stable chronic obstructive pulmonary disease. Thirty males (GOLD stages II-III) underwent a cardiopulmonary exercise test to the limit of tolerance (Tlim) at 75% of peak work rate on an electronically braked cycle ergometer. Exercise-induced dynamic hyperinflation was considered to be present when end-expiratory (EE) VCW increased in relation to resting values. There was a noticeable heterogeneity in the patterns of VCW regulation as EEVCW increased non-linearly in 17/30 “hyperinflators” and decreased in 13/30 “non-hyperinflators” (P < 0.05). EEVAB decreased slightly in 8 of the “hyperinflators”, thereby reducing and slowing the rate of increase in end-inspiratory (EI) VCW (P < 0.05). In contrast, decreases in EEVCW in the “non-hyperinflators” were due to the combination of stable EEVRC with marked reductions in EEVAB. These patients showed lower EIVCW and end-exercise dyspnea scores but longer Tlim than their counterparts (P < 0.05). Dyspnea increased and Tlim decreased non-linearly with a faster rate of increase in EIVCW regardless of the presence or absence of dynamic hyperinflation (P < 0.001). However, no significant between-group differences were observed in metabolic, pulmonary gas exchange and cardiovascular responses to exercise. Chest wall volumes are continuously regulated during exercise in order to postpone (or even avoid) their migration to higher operating volumes in patients with COPD, a dynamic process that is strongly dependent on the behavior of the abdominal compartment. PMID:23250012

  18. Magnetic Resonance Imaging Appearances in the Postoperative Breast: The Clinical Target Volume-Tumor and Its Relationship to the Chest Wall

    SciTech Connect

    Whipp, Elisabeth C. Halliwell, Michael

    2008-09-01

    Purpose: To describe and measure the postoperative complexes and their relationship to the chest wall in 100 randomly chosen MRI breast scans, to attempt a better understanding of the changes taking place in the postoperative breast. Methods and Materials: Appearances and measurements of MRI postoperative cavities were analyzed in a cohort of 100 randomly selected patients who underwent a single open MRI scan in the conventional breast radiotherapy treatment position before routine two-dimensional simulation. Results: Magnetic resonance imaging appearances of postoperative cavities seem to differ qualitatively from descriptions of CT and ultrasound cavities in the literature. Rather than being principally homogeneous, heterogeneous cavities were seen in 85%, irregular in 51%. The size of cavity was inversely related to the time elapsed since surgery. Cavities directly touched the chest wall in 53% of cases; 89% lay within 10 mm of the chest wall. Regular, annular concentric rings of differing signal were seen in 32% of cases; such appearances have not been previously described. These patterns suggest that seromas may not shrink entirely as a result of simple serous fluid absorption; instead, new tissue may be being laid down. Because large, regular spheroidal/ellipsoidal cavities with crisp margins may be seromas under pressure, greater target shifts during radiation may need to be anticipated in such cases. Conclusions: Postsurgical cavities in the conserved breast on MRI are commonly heterogeneous, irregular, and lie close to the chest wall. Magnetic resonance imaging studies may help in better understanding the natural history of postoperative cavities.

  19. Protocol for PIT: a phase III trial of prophylactic irradiation of tracts in patients with malignant pleural mesothelioma following invasive chest wall intervention

    PubMed Central

    Bayman, N; Ardron, D; Ashcroft, L; Baldwin, D R; Booton, R; Darlison, L; Edwards, J G; Lang-Lazdunski, L; Lester, J F; Peake, M; Rintoul, R C; Snee, M; Taylor, P; Lunt, C

    2016-01-01

    Introduction Histological diagnosis of malignant mesothelioma requires an invasive procedure such as CT-guided needle biopsy, thoracoscopy, video-assisted thorascopic surgery (VATs) or thoracotomy. These invasive procedures encourage tumour cell seeding at the intervention site and patients can develop tumour nodules within the chest wall. In an effort to prevent nodules developing, it has been widespread practice across Europe to irradiate intervention sites postprocedure—a practice known as prophylactic irradiation of tracts (PIT). To date there has not been a suitably powered randomised trial to determine whether PIT is effective at reducing the risk of chest wall nodule development. Methods and analysis In this multicentre phase III randomised controlled superiority trial, 374 patients who can receive radiotherapy within 42 days of a chest wall intervention will be randomised to receive PIT or no PIT. Patients will be randomised on a 1:1 basis. Radiotherapy in the PIT arm will be 21 Gy in three fractions. Subsequent chemotherapy is given at the clinicians’ discretion. A reduction in the incidence of chest wall nodules from 15% to 5% in favour of radiotherapy 6 months after randomisation would be clinically significant. All patients will be followed up for up to 2 years with monthly telephone contact and at least four outpatient visits in the first year. Ethics and dissemination PIT was approved by NRES Committee North West—Greater Manchester West (REC reference 12/NW/0249) and recruitment is currently on-going, the last patient is expected to be randomised by the end of 2015. The analysis of the primary end point, incidence of chest wall nodules 6 months after randomisation, is expected to be published in 2016 in a peer reviewed journal and results will also be presented at scientific meetings and summary results published online. A follow-up analysis is expected to be published in 2018. Trial registration number ISRCTN04240319; NCT01604005; Pre

  20. Chest Wall Radiotherapy: Middle Ground for Treatment of Patients With One to Three Positive Lymph Nodes After Mastectomy

    SciTech Connect

    MacDonald, Shannon M.; Abi-Raad, Rita F.; Alm El-Din, Mohamed A.; Niemierko, Andrzej; Kobayashi, Wendy; McGrath, John J.; Goldberg, Saveli I.; Powell, Simon; Smith, Barbara; Taghian, Alphonse G.

    2009-12-01

    Purpose: To evaluate the outcomes for patients with Stage II breast cancer and one to three positive lymph nodes after mastectomy who were treated with observation or adjuvant radiotherapy to the chest wall (CW) with or without the regional lymphatics. Methods and Materials: We retrospectively analyzed 238 patients with Stage II breast cancer (one to three positive lymph nodes) treated with mastectomy at the Massachusetts General Hospital between 1990 and 2004. The estimates of locoregional recurrence (LRR), disease-free survival (DFS), and overall survival were analyzed according to the delivery of radiotherapy and multiple prognostic factors. Results: LRR and DFS were significantly improved by postmastectomy radiotherapy (PMRT), with a 5- and 10-year LRR rate without PMRT of 6% and 11%, respectively and, with PMRT, of 0% at both 5 and 10 years (p = .02). The 5- and 10-year DFS rate without PMRT was 85% and 75%, respectively, and, with PMRT, was 93% at both 5 and 10 years (p = .03). A similar benefit was found for patients treated with RT to the CW alone. The LRR, DFS, and overall survival rate for patients treated to the CW only was 0%, 96%, and 95% at 10 years, respectively. Conclusion: Our data suggest that adjuvant PMRT to the CW alone provides excellent disease control for patients with breast cancer <5 cm with one to three positive lymph nodes.

  1. Treatment techniques for 3D conformal radiation to breast and chest wall including the internal mammary chain

    SciTech Connect

    Sonnik, Deborah; Selvaraj, Raj N. . E-mail: selvarajrn@upmc.edu; Faul, Clare; Gerszten, Kristina; Heron, Dwight E.; King, Gwendolyn C.

    2007-04-01

    Breast, chest wall, and regional nodal irradiation have been associated with an improved outcome in high-risk breast cancer patients. Complex treatment planning is often utilized to ensure complete coverage of the target volume while minimizing the dose to surrounding normal tissues. The 2 techniques evaluated in this report are the partially wide tangent fields (PWTFs) and the 4-field photon/electron combination (the modified 'Kuske Technique'). These 2 techniques were evaluated in 10 consecutive breast cancer patients. All patients had computerized tomographic (CT) scans for 3D planning supine on a breast board. The breast was defined clinically by the physician and confirmed radiographically with radiopaque bebes. The resulting dose-volume histograms (DVHs) of normal and target tissues were then compared. The deep tangent field with blocks resulted in optimal coverage of the target and the upper internal mammary chain (IMC) while sparing of critical and nontarget tissues. The wide tangent technique required less treatment planning and delivery time. We compared the 2 techniques and their resultant DVHs and feasibility in a busy clinic.

  2. Occurrence of Breast Cancer After Chest Wall Irradiation for Pediatric Cancer, as Detected by a Multimodal Screening Program

    SciTech Connect

    Terenziani, Monica; Casalini, Patrizia; Scaperrotta, Gianfranco; Gandola, Lorenza; Trecate, Giovanna; Catania, Serena; Cefalo, Graziella; Conti, Alberto; Massimino, Maura; Meazza, Cristina; Podda, Marta; Spreafico, Filippo; Suman, Laura; Gennaro, Massimiliano

    2013-01-01

    Purpose: To assess the occurrence of breast cancer (BC) after exposure to ionizing radiation for pediatric cancer, by means of a multimodal screening program. Patients and Methods: We identified 86 patients who had received chest wall radiation therapy for pediatric cancer. Clinical breast examination (CBE), ultrasound (US), and mammography (MX) were performed yearly. Magnetic resonance imaging (MRI) was added as of October 2007. We calculated the risk of developing BC by radiation therapy dose, patient age, and menarche before or after primary treatment. Results: Eleven women developed a BC from July 2002-February 2010. The sensitivity of the screening methods was 36% for CBE, 73% for MX, 55% for US, and 100% for MRI; the specificity was 91%, 99%, 95%, and 80% for CBE, MX, US, and MRI, respectively. The annual BC detection rate was 2.9%. The median age at BC diagnosis was 33 years. Although age had no influence, menarche before as opposed to after radiation therapy correlated significantly with BC (P=.027): the annual BC detection rate in the former subgroup was 5.3%. Conclusions: Mammography proved more sensitive and specific in our cohort of young women than CBE or US. Magnetic resonance imaging proved 100% sensitive (but this preliminary finding needs to be confirmed). Our cohort of patients carries a 10-fold BC risk at an age more than 20 years younger than in the general population.

  3. The MUSIC algorithm for impedance tomography of small inclusions from discrete data

    NASA Astrophysics Data System (ADS)

    Lechleiter, A.

    2015-09-01

    We consider a point-electrode model for electrical impedance tomography and show that current-to-voltage measurements from finitely many electrodes are sufficient to characterize the positions of a finite number of point-like inclusions. More precisely, we consider an asymptotic expansion with respect to the size of the small inclusions of the relative Neumann-to-Dirichlet operator in the framework of the point electrode model. This operator is naturally finite-dimensional and models difference measurements by finitely many small electrodes of the electric potential with and without the small inclusions. Moreover, its leading-order term explicitly characterizes the centers of the small inclusions if the (finite) number of point electrodes is large enough. This characterization is based on finite-dimensional test vectors and leads naturally to a MUSIC algorithm for imaging the inclusion centers. We show both the feasibility and limitations of this imaging technique via two-dimensional numerical experiments, considering in particular the influence of the number of point electrodes on the algorithm’s images.

  4. Chest wall segmentation in automated 3D breast ultrasound using rib shadow enhancement and multi-plane cumulative probability enhanced map

    NASA Astrophysics Data System (ADS)

    Kim, Hyeonjin; Kim, Hannah; Hong, Helen

    2015-03-01

    We propose an automatic segmentation method of chest wall in 3D ABUS images using rib shadow enhancement and multi-planar cumulative probability enhanced map. For the identification of individual dark rib shadows, each rib shadow is enhanced using intensity transfer function and 3D sheet-like enhancement filtering. Then, wrongly enhanced intercostal regions and small fatty tissues are removed using coronal and sagittal cumulative probability enhanced maps. The large fatty tissues with globular and sheet-like shapes at the top of rib shadow are removed using shape and orientation analysis based on moment matrix. Detected chest walls are connected with cubic B-spline interpolation. Experimental results show that the Dice similarity coefficient of proposed method as comparison with two manually outlining results provides over 90% in average.

  5. Management of a Chest-Wall Soft-Tissue Tumor Caused by an Infection with the Larval Tapeworm Pathogen Taenia crassiceps

    PubMed Central

    Roesel, Christian; Welter, Stefan; Stamatis, Georgios; Theegarten, Dirk; Tappe, Dennis

    2014-01-01

    A chest-wall lesion of an immunocompetent patient was initially suspicious for a malignant tumor. Histopathological and polymerase chain reaction examinations revealed an infection with the larval stage of the tapeworm Taenia crassiceps. Curative resection of the tumorous lesion was performed. Treatment options for immunocompromised patients and patients without known immune defect are discussed, because most of the infections occur in immunocompromised individuals. PMID:24914004

  6. Inhibitory effect of cervical trachea and chest wall vibrations on cough reflex sensitivity and perception of urge-to-cough in healthy male never-smokers

    PubMed Central

    2013-01-01

    Background Non-pharmacological options for symptomatic management of cough are desired. Although chest wall mechanical vibration is known to ameliorate cough reflex sensitivity, the effect of mechanical vibrations on perceptions of urge-to-cough has not been studied. Therefore, we investigated the effect of mechanical vibration of cervical trachea, chest wall and femoral muscle on cough reflex sensitivity, perceptions of urge-to-cough as well as dyspnea. Methods Twenty-four healthy male never-smokers were investigated for cough reflex sensitivity, perceptions of the urge-to-cough and dyspnea with or without mechanical vibration. Cough reflex sensitivity and urge-to-cough were evaluated by the inhalation of citric acid. The perception of dyspnea was evaluated by Borg scores during applications of external inspiratory resistive loads. Mechanical vibration was applied by placing a vibrating tuning fork on the skin surface of cervical trachea, chest wall and femoral muscle. Results Cervical trachea vibration significantly increased cough reflex threshold, as expressed by the lowest concentration of citric acid that elicited five or more coughs (C5), and urge-to-cough threshold, as expressed by the lowest concentration of citric acid that elicited urge-to-cough (Cu), but did not significantly affect dypnea sensation during inspiratory resistive loading. On the other hand, the chest wall vibration not only significantly increased C5 and Cu but also significantly ameliorated the load-response curve of dyspnea sensation. Conclusions Both cervical and trachea vibrations significantly inhibited cough reflex sensitivity and perception of urge-to-cough. These vibration techniques might be options for symptomatic cough management. PMID:24088411

  7. Low-dose Photofrin-induced PDT offers excellent clinical response with minimal morbidity in chest wall recurrence of breast cancer

    NASA Astrophysics Data System (ADS)

    Allison, Ron; Mang, Thomas S.

    2000-03-01

    Limited therapeutic options exist when chest wall recurrence form breast cancer progresses despite standard salvage treatment. As photodynamic therapy offers excellent response for cutaneous lesions this may be a possible indication for PDT. A total of 102 treatment fields were illuminated on 9 women with biopsy proven chest wall recurrence of breast cancer which was progressing despite salvage surgery, radiation, and chemi-hormonal therapy. PDT consisted of outpatient IV infusion of Photofrin at 0.8 mg/kg followed 48 hours laser by illumination at 140-170 J/cm2 via a KTP Yag laser coupled to a dye unit. No patient was lost to follow up. At 6 months post PDT; complete response, defined as total lesion elimination was 89 percent, partial response 8 percent, and no response 3 percent. No photosensitivity was seen and no patient developed scarring, fibrosis, or healing difficulties. Low dose Photofrin induced PDT is very active against chest wall lesions. Despite fragile and heavily pre-treated tissues, excellent clinical and cosmetic outcome was obtained. PDT is an underutilized modality for this indication.

  8. Highly sensitive monitoring of chest wall dynamics and acoustics provides diverse valuable information for evaluating ventilation and diagnosing pneumothorax.

    PubMed

    Pesin, Jimy; Faingersh, Anna; Waisman, Dan; Landesberg, Amir

    2014-06-15

    Current practice of monitoring lung ventilation in neonatal intensive care units, utilizing endotracheal tube pressure and flow, end-tidal CO2, arterial O2 saturation from pulse oximetry, and hemodynamic indexes, fails to account for asymmetric pathologies and to allow for early detection of deteriorating ventilation. This study investigated the utility of bilateral measurements of chest wall dynamics and sounds, in providing early detection of changes in the mechanics and distribution of lung ventilation. Nine healthy New Zealand rabbits were ventilated at a constant pressure, while miniature accelerometers were attached to each side of the chest. Slowly progressing pneumothorax was induced by injecting 1 ml/min air into the pleural space on either side of the chest. The end of the experiment (tPTX) was defined when arterial O2 saturation from pulse oximetry dropped <90% or when vigorous spontaneous breathing began, since it represents the time of clinical detection using common methods. Consistent and significant changes were observed in 15 of the chest dynamics parameters. The most meaningful temporal changes were noted for features extracted from subsonic dynamics (<10 Hz), e.g., tidal amplitude, energy, and autoregressive poles. Features from the high-frequency band (10-200 Hz), e.g., energy and entropy, exhibited smaller but significant changes. At 70% tPTX, identification of asymmetric ventilation was attained for all animals. Side identification of the pneumothorax was achieved at 50% tPTX, within a 95% confidence interval. Diagnosis was, on average, 34.1 ± 18.8 min before tPTX. In conclusion, bilateral monitoring of the chest dynamics and acoustics provide novel information that is sensitive to asymmetric changes in ventilation, enabling early detection and localization of pneumothorax. PMID:24790013

  9. Dose-Volume Parameters Predict for the Development of Chest Wall Pain After Stereotactic Body Radiation for Lung Cancer

    SciTech Connect

    Mutter, Robert W.; Liu Fan; Abreu, Andres; Yorke, Ellen; Jackson, Andrew; Rosenzweig, Kenneth E.

    2012-04-01

    Purpose: Chest wall (CW) pain has recently been recognized as an important adverse effect of stereotactic body radiation therapy (SBRT) for non-small-cell lung cancer (NSCLC). We developed a dose-volume model to predict the development of this toxicity. Methods and Materials: A total of 126 patients with primary, clinically node-negative NSCLC received three to five fractions of SBRT to doses of 40-60 Gy and were prospectively followed. The dose-absolute volume histograms of two different definitions of the CW as an organ at risk (CW3cm and CW2cm) were examined for all 126 patients. Results: With a median follow-up of 16 months, the 2-year estimated actuarial incidence of Grade {>=} 2 CW pain was 39%. The median time to onset of Grade {>=} 2 CW pain (National Cancer Institute Common Terminology Criteria for Adverse Events, Version 3.0) was 9 months. There was no predictive advantage for biologically corrected dose over physical dose. Neither fraction number (p = 0.07) nor prescription dose (p = 0.07) were significantly correlated with the development of Grade {>=} 2 CW pain. Cox Proportional Hazards analysis identified significant correlation with a broad range of dose-volume combinations, with the CW volume receiving 30 Gy (V30) as one of the strongest predictors (p < 0.001). CW2cm consistently enabled better prediction of CW toxicity. When a physical dose of 30 Gy was received by more than 70 cm{sup 3} of CW2cm, there was a significant correlation with Grade {>=} 2 CW pain (p = 0.004). Conclusions: CW toxicity after SBRT is common and long-term follow-up is needed to identify affected patients. A volume of CW {>=} 70 cm{sup 3} receiving 30 Gy is significantly correlated with Grade {>=} 2 CW pain. We are currently applying this constraint at our institution for patients receiving thoracic SBRT. An actuarial atlas of our data is provided as an electronic supplement to facilitate data-sharing and meta-analysis relating to CW pain.

  10. DOSE–VOLUME PARAMETERS PREDICT FOR THE DEVELOPMENT OF CHEST WALL PAIN AFTER STEREOTACTIC BODY RADIATION FOR LUNG CANCER

    PubMed Central

    Mutter, Robert W.; Liu, Fan; Abreu, Andres; Yorke, Ellen; Jackson, Andrew; Rosenzweig, Kenneth E.

    2013-01-01

    Purpose Chest wall (CW) pain has recently been recognized as an important adverse effect of stereotactic body radiation therapy (SBRT) for non–small-cell lung cancer (NSCLC). We developed a dose–volume model to predict the development of this toxicity. Methods and Materials A total of 126 patients with primary, clinically node-negative NSCLC received three to five fractions of SBRT to doses of 40–60 Gy and were prospectively followed. The dose–absolute volume histograms of two different definitions of the CW as an organ at risk (CW3cm and CW2cm) were examined for all 126 patients. Results With a median follow-up of 16 months, the 2-year estimated actuarial incidence of Grade ≥ 2 CW pain was 39%. The median time to onset of Grade ≥ 2 CW pain (National Cancer Institute Common Terminology Criteria for Adverse Events, Version 3.0) was 9 months. There was no predictive advantage for biologically corrected dose over physical dose. Neither fraction number (p = 0.07) nor prescription dose (p = 0.07) were significantly correlated with the development of Grade ≥ 2 CW pain. Cox Proportional Hazards analysis identified significant correlation with a broad range of dose-volume combinations, with the CW volume receiving 30 Gy (V30) as one of the strongest predictors (p < 0.001). CW2cm consistently enabled better prediction of CW toxicity. When a physical dose of 30 Gy was received by more than 70 cm3 of CW2cm, there was a significant correlation with Grade ≥ 2 CW pain (p = 0.004). Conclusions CW toxicity after SBRT is common and long-term follow-up is needed to identify affected patients. A volume of CW ≥ 70 cm3 receiving 30 Gy is significantly correlated with Grade ≥ 2 CW pain. We are currently applying this constraint at our institution for patients receiving thoracic SBRT. An actuarial atlas of our data is provided as an electronic supplement to facilitate data-sharing and meta-analysis relating to CW pain. PMID:21868173

  11. Design of a Broadband Electrical Impedance Matching Network for Piezoelectric Ultrasound Transducers Based on a Genetic Algorithm

    PubMed Central

    An, Jianfei; Song, Kezhu; Zhang, Shuangxi; Yang, Junfeng; Cao, Ping

    2014-01-01

    An improved method based on a genetic algorithm (GA) is developed to design a broadband electrical impedance matching network for piezoelectric ultrasound transducer. A key feature of the new method is that it can optimize both the topology of the matching network and perform optimization on the components. The main idea of this method is to find the optimal matching network in a set of candidate topologies. Some successful experiences of classical algorithms are absorbed to limit the size of the set of candidate topologies and greatly simplify the calculation process. Both binary-coded GA and real-coded GA are used for topology optimization and components optimization, respectively. Some calculation strategies, such as elitist strategy and clearing niche method, are adopted to make sure that the algorithm can converge to the global optimal result. Simulation and experimental results prove that matching networks with better performance might be achieved by this improved method. PMID:24743156

  12. Reproducibility of The Abdominal and Chest Wall Position by Voluntary Breath-Hold Technique Using a Laser-Based Monitoring and Visual Feedback System

    SciTech Connect

    Nakamura, Katsumasa . E-mail: nakam@radiol.med.kyushu-u.ac.jp; Shioyama, Yoshiyuki; Nomoto, Satoru; Ohga, Saiji; Toba, Takashi; Yoshitake, Tadamasa; Anai, Shigeo; Terashima, Hiromi; Honda, Hiroshi

    2007-05-01

    Purpose: The voluntary breath-hold (BH) technique is a simple method to control the respiration-related motion of a tumor during irradiation. However, the abdominal and chest wall position may not be accurately reproduced using the BH technique. The purpose of this study was to examine whether visual feedback can reduce the fluctuation in wall motion during BH using a new respiratory monitoring device. Methods and Materials: We developed a laser-based BH monitoring and visual feedback system. For this study, five healthy volunteers were enrolled. The volunteers, practicing abdominal breathing, performed shallow end-expiration BH (SEBH), shallow end-inspiration BH (SIBH), and deep end-inspiration BH (DIBH) with or without visual feedback. The abdominal and chest wall positions were measured at 80-ms intervals during BHs. Results: The fluctuation in the chest wall position was smaller than that of the abdominal wall position. The reproducibility of the wall position was improved by visual feedback. With a monitoring device, visual feedback reduced the mean deviation of the abdominal wall from 2.1 {+-} 1.3 mm to 1.5 {+-} 0.5 mm, 2.5 {+-} 1.9 mm to 1.1 {+-} 0.4 mm, and 6.6 {+-} 2.4 mm to 2.6 {+-} 1.4 mm in SEBH, SIBH, and DIBH, respectively. Conclusions: Volunteers can perform the BH maneuver in a highly reproducible fashion when informed about the position of the wall, although in the case of DIBH, the deviation in the wall position remained substantial.

  13. Sternal Cleft and Pectus Excavatum: A Combined Approach for the Correction of a Complex Anterior Chest Wall Malformation in a Teenager.

    PubMed

    Tocchioni, Francesca; Ghionzoli, Marco; Lo Piccolo, Roberto; Deaconu, Diana E; Facchini, Flavio; Milanez De Campos, Jose R; Messineo, Antonio

    2015-06-01

    Congenital sternal cleft is a rare chest wall malformation. Because of the flexibility of the chest in infants, surgical repair should be performed by primary closure in the neonatal period. In adolescents and adults, different techniques have been suggested to overcome the lack of sternal bone tissue. We describe a very rare case of an 18-year-old woman with a complete bifid sternum associated with pectus excavatum for whom a satisfactory cosmetic and functional result was obtained by adequate surgical planning, which entailed a combination of two standardized surgical techniques. PMID:26046903

  14. Should Postmastectomy Radiotherapy to the Chest Wall and Regional Lymph Nodes Be Standard for Patients with 1–3 Positive Lymph Nodes?

    PubMed Central

    Offersen, Birgitte V.; Brodersen, Hans-Jürgen; Nielsen, Mette M.; Overgaard, Jens; Overgaard, Marie

    2011-01-01

    The indication for adjuvant postmastectomy radiotherapy (PMRT) in breast cancer patients with small tumors and 1–3 macrometastases in the axilla remains a controversial issue, despite the recommendation that PMRT should be applied in these patients in the most recent overview by the Early Breast Cancer Trialists’ Collaborative Group. In this report, we discuss the available data on the benefit from PMRT in patients diagnosed with N1 breast cancer. Based on this, we recommend adjuvant PMRT to the chest wall and regional lymph nodes in patients diagnosed with early node-positive breast cancer. PMID:22619643

  15. [Influences of chest deformation by upper abdominal retractor on respiratory system impedance during abdominal surgery].

    PubMed

    Oka, T; Ozawa, Y; Sato, J

    1999-02-01

    The present study was carried out to clarify the effects of chest deformation by upper abdominal retractor on respiratory system impedance during abdominal surgery. We measured the impedances of respiratory system (RS), lung, and chest wall (CW) in nine anesthetized paralyzed subjects employing a pseudorandom noise forced volume oscillation technique. These measurements were performed before and after the lifting chest wall by upper abdominal retractor. The effects of chest deformation was significant on the impedances of RS, lung, while no discernible effect was found in CW impedance. Lifting chest wall decreased RS resistance which was totally accounted for by the decrease in lung resistance, whereas the lifting did not affect reactance in either RS or lung. The mathematical modeling showed the significant lifting effect on the resistance of the parenchyma. In conclusion, change in RS mechanics produced by chest deformation by upper abdominal retractor is dominated in lung but not in CW. Among the lung mechanical components, parenchyma is the primary site of the lifting effect. PMID:10087819

  16. EM algorithm applied for estimating non-stationary region boundaries using electrical impedance tomography

    NASA Astrophysics Data System (ADS)

    Khambampati, A. K.; Rashid, A.; Kim, B. S.; Liu, Dong; Kim, S.; Kim, K. Y.

    2010-04-01

    EIT has been used for the dynamic estimation of organ boundaries. One specific application in this context is the estimation of lung boundaries during pulmonary circulation. This would help track the size and shape of lungs of the patients suffering from diseases like pulmonary edema and acute respiratory failure (ARF). The dynamic boundary estimation of the lungs can also be utilized to set and control the air volume and pressure delivered to the patients during artificial ventilation. In this paper, the expectation-maximization (EM) algorithm is used as an inverse algorithm to estimate the non-stationary lung boundary. The uncertainties caused in Kalman-type filters due to inaccurate selection of model parameters are overcome using EM algorithm. Numerical experiments using chest shaped geometry are carried out with proposed method and the performance is compared with extended Kalman filter (EKF). Results show superior performance of EM in estimation of the lung boundary.

  17. Optimal design of a standing-wave accelerating tube with a high shunt impedance based on a genetic algorithm

    NASA Astrophysics Data System (ADS)

    Tang, Zhenxing; Pei, Yuanji; Pang, Jian

    2015-08-01

    In this paper, we present an optimal design based on a genetic algorithm for a compact standing-wave (SW) accelerating tube with an operating frequency of 2998 MHz for industrial and medical applications. It consists of bi-periodic structures with a nose cone whose inter-cavity coupling is achieved through electric coupling rather than magnetic coupling. A mathematical model is established to optimize the arc at the cavity wall to reduce the microwave power loss and to optimize the nose cone to increase the electric field along the axis to achieve a high shunt impedance. The simulation results indicate that with the proper nose cone and arc, the shunt impedance of the cavity can be as high as 114 MΩ / m. Afterward, we present the tuning of the tube using SUPERFISH and the calculation of the beam dynamics using ASTRA and Parmela. The total length of the optimal tube is only 30.175 cm. Finally, a coupler is designed with a small-aperture coupling using CST MICROWAVE STUDIO.

  18. Chest wall stabilization and reconstruction: short and long-term results 5 years after the introduction of a new titanium plates system

    PubMed Central

    Sollitto, Francesco; Loizzi, Domenico; Di Gennaro, Francesco; Scarascia, Daniele; Carlucci, Annalisa; Giudice, Giuseppe; Armenio, Andrea; Ludovico, Rossana; Loizzi, Michele

    2016-01-01

    Background We report short and long-term results with the dedicated Synthes® titanium plates system, introduced 5 years ago, for chest wall stabilization and reconstruction. Methods We retrospectively analyzed (January 2010 to December 2014) 27 consecutive patients (22 males, 5 females; range 16–83 years, median age 60 years), treated with this system: primary [3] and secondary [8] chest wall tumor; flail chest [5]; multiple ribs fractures [5]; sternal dehiscence-diastasis [3]; sternal fracture [1]; sternoclavicular joint dislocation [1]; Poland syndrome [1]. Short-term results were evaluated as: operating time, post-operative morbidity, mortality, hospital stay; long-term results as: survival, plates-related morbidity, spirometric values, chest pain [measured with Verbal Rating Scale (VRS) and SF12 standard V1 questionnaire]. Results Each patient received from 1 to 10 (median 2) titanium plates/splints; median operating time was 150 min (range: 115–430 min). Post-operative course: 15 patients (55.6%) uneventful, 10 (37%) minor complications, 2 (7.4%) major complications; no post-operative mortality. Median post-operative hospital stay was 13 days (range: 5–129 days). At a median follow-up of 20 months (range: 1–59 months), 21 patients (78%) were alive, 6 (22%) died. Three patients presented long-term plates-related morbidity: plates rupture [2], pin plate dislodgment [1]; two required a second surgical look. One-year from surgery median spirometric values were: FVC 3.31 L (90%), FEV1 2.46 L (78%), DLCO 20.9 mL/mmHg/min (76%). On 21 alive patients, 7 (33.3%) reported no pain (VRS score 0), 10 (47.6%) mild (score 2), 4 (19.1%) moderate (score 4), no-one severe (score >4); 15 (71.5%) reported none or mild, 6 (28.5%) moderate pain influencing quality of life. Conclusions An optimal chest wall stabilization and reconstruction was achieved with the Synthes® titanium plates system, with minimal morbidity, no post-operative mortality, acceptable operating time

  19. Radio-guided occult lesion localisation using iodine 125 Seeds “ROLLIS” to guide surgical removal of an impalpable posterior chest wall melanoma metastasis

    SciTech Connect

    Dissanayake, Shashini; Dissanayake, Deepthi; Taylor, Donna B

    2015-09-15

    Cancer screening and surveillance programmes and the use of sophisticated imaging tools such as positron emission tomography-computed tomography (PET-CT) have increased the detection of impalpable lesions requiring imaging guidance for excision. A new technique involves intra-lesional insertion of a low-activity iodine-125 ({sup 125}I) seed and detection of the radioactive signal in theatre using a hand-held gamma probe to guide surgery. Whilst several studies describe using this method to guide the removal of impalpable breast lesions, only a handful of publications report its use to guide excision of lesions outside the breast. We describe a case in which radio-guided occult lesion localisation using an iodine 125 seed was used to guide excision of an impalpable posterior chest wall metastasis detected on PET-CT.

  20. [Pleuroperitoneal communication due to diaphragmatic injury as a complication of chest wall resection in a peritoneal dialysis patient; report of a case].

    PubMed

    Kanauchi, Naoki; Oizumi, H; Kato, H; Endo, M; Sadahiro, M

    2009-09-01

    A 78-year-old female undergoing peritoneal dialysis due to chronic renal failure was admitted to our hospital because of a tumor on her right chest wall. The diagnosis was recurrence of hepatocellular carcinoma in the thoracic wall, and a combined resection of the thoracic wall and diaphragm was performed. Peritoneal dialysis was resumed 7 days after surgery, but a right pleural effusion was observed after 6 days of dialysis. Surgery was performed because failure of sutures related to the excised diaphragm was suspected. A thoracotomy revealed a large defect, about 1 cm in size, caused by injury of the diaphragm by an edge of the resected rib at the another site of a previous resection of the diaphragm. This defect was closed with sutures and the diaphragm was reinforced with a polyglycolic acid felt and fibrin glue. Peritoneal dialysis was resumed 7 days after surgery and has continued to date without recurrence. PMID:19764505

  1. Poster — Thur Eve — 09: Evaluation of electrical impedance and computed tomography fusion algorithms using an anthropomorphic phantom

    SciTech Connect

    Chugh, Brige Paul; Krishnan, Kalpagam; Liu, Jeff; Kohli, Kirpal

    2014-08-15

    Integration of biological conductivity information provided by Electrical Impedance Tomography (EIT) with anatomical information provided by Computed Tomography (CT) imaging could improve the ability to characterize tissues in clinical applications. In this paper, we report results of our study which compared the fusion of EIT with CT using three different image fusion algorithms, namely: weighted averaging, wavelet fusion, and ROI indexing. The ROI indexing method of fusion involves segmenting the regions of interest from the CT image and replacing the pixels with the pixels of the EIT image. The three algorithms were applied to a CT and EIT image of an anthropomorphic phantom, constructed out of five acrylic contrast targets with varying diameter embedded in a base of gelatin bolus. The imaging performance was assessed using Detectability and Structural Similarity Index Measure (SSIM). Wavelet fusion and ROI-indexing resulted in lower Detectability (by 35% and 47%, respectively) yet higher SSIM (by 66% and 73%, respectively) than weighted averaging. Our results suggest that wavelet fusion and ROI-indexing yielded more consistent and optimal fusion performance than weighted averaging.

  2. Early Indication of Decompensated Heart Failure in Patients on Home-Telemonitoring: A Comparison of Prediction Algorithms Based on Daily Weight and Noninvasive Transthoracic Bio-impedance

    PubMed Central

    Bonomi, Alberto G; Goode, Kevin M; Reiter, Harald; Habetha, Joerg; Amft, Oliver; Cleland, John GF

    2016-01-01

    Background Heart Failure (HF) is a common reason for hospitalization. Admissions might be prevented by early detection of and intervention for decompensation. Conventionally, changes in weight, a possible measure of fluid accumulation, have been used to detect deterioration. Transthoracic impedance may be a more sensitive and accurate measure of fluid accumulation. Objective In this study, we review previously proposed predictive algorithms using body weight and noninvasive transthoracic bio-impedance (NITTI) to predict HF decompensations. Methods We monitored 91 patients with chronic HF for an average of 10 months using a weight scale and a wearable bio-impedance vest. Three algorithms were tested using either simple rule-of-thumb differences (RoT), moving averages (MACD), or cumulative sums (CUSUM). Results Algorithms using NITTI in the 2 weeks preceding decompensation predicted events (P<.001); however, using weight alone did not. Cross-validation showed that NITTI improved sensitivity of all algorithms tested and that trend algorithms provided the best performance for either measurement (Weight-MACD: 33%, NITTI-CUSUM: 60%) in contrast to the simpler rules-of-thumb (Weight-RoT: 20%, NITTI-RoT: 33%) as proposed in HF guidelines. Conclusions NITTI measurements decrease before decompensations, and combined with trend algorithms, improve the detection of HF decompensation over current guideline rules; however, many alerts are not associated with clinically overt decompensation. PMID:26892844

  3. Dystrophic calcinosis with both a huge calcified mass in the cervical spine and calcification in the chest wall in a patient with rheumatoid overlap syndrome.

    PubMed

    Nakamura, Tadashi; Hirakawa, Kei; Takaoka, Hirokazu; Iyama, Ken-Ichi

    2016-05-01

    Dystrophic calcinosis in soft tissue occurs in damaged or devitalized tissues in the presence of normal calcium and phosphorous metabolism. It is often noted in subcutaneous tissues in patients with collagen vascular diseases and may involve a relatively localized area or be widespread. A 74-year-old Japanese woman with an overlap of rheumatoid arthritis, Sjögren's syndrome, and systemic sclerosis developed a huge tumor-like mass at the atlanto-axial vertebral joint region that caused severe cervical pain and difficulty in activities of daily living. She also had subcutaneous dystrophic calcification in the soft tissue of the chest wall. Calcinosis associated with systemic sclerosis is a well-recognized phenomenon, but a destructive paraspinal tumor in the cervical spine associated with overlap syndrome is extremely unique. Because calcinosis in spinal locations can be complicated by neurological involvement, patients with progressive symptoms may require surgical intervention. Surgical resection and biological therapy improved this patient's life and activities of daily living. Calcinosis is common in the conditions reviewed here, and different agents have been used for treatment. However, calcinosis management is poorly organized and lacks an accepted classification, systematic studies, and clinical therapeutic trials. The association of calcinosis and collagen vascular diseases is clinically and etiologically important. Although a combination of calcinosis and rheumatoid overlap syndrome is rare, various collagen vascular diseases may occur simultaneously. A perceptive diagnostic approach toward these diseases is critical, and early diagnosis and treatment are needed to prevent dystrophic calcinosis. PMID:24894107

  4. Salmonella Abscess of the Anterior Chest Wall in a Patient With Type 2 Diabetes and Poor Glycemic Control: A Case Report.

    PubMed

    Chiao, Hao-Yu; Wang, Chi-Yu; Wang, Chih-Hsin

    2016-03-01

    Salmonella can cause extra-intestinal focal infections as well as gastrointestinal problems. A few cases of Salmonella skin and soft tissue infection have been documented in immunocompromised patients such as persons with type 2 diabetes and poor glycemic control. A case study is presented of a 30-year-old man with a 10-year history of poorly controlled (HbA1C 11.7%) diabetes mellitus who presented with a ruptured nodule resulting in a wound with signs of infection over his anterior chest region of 1-month duration. He had been taking amoxycillin/clavulanate for the week previous to presentation at the authors' facility. Following sharp debridement, the ulcerative wound deteriorated and a chest wall abscess developed. Bacterial culture results were positive for Salmonella group D, resistant to ampicillin and susceptible to ceftriaxone and ciprofloxacin. The patient underwent surgical debridement, resulting in a wound 7 cm x 4 cm, and was provided ceftriaxone 2.0 g intravenously daily along with insulin therapy. After surgical debridement, a local rotational flap was created for wound closure and reconstruction. The patient was discharged 1 week later on oral antibiotic therapy for 1 week. His wound was completely healed without recurrence at his 4-month follow-up. For this patient, addressing glycemic issues, identifying the infectious organism, and providing appropriate therapy, radical debridement, and flap surgery helped heal an advanced soft tissue infection. In immunocompromised patients with skin or soft tissue infections, the presence of Salmonella should be considered. PMID:26978859

  5. Development of an imaging-planning program for screen/film and computed radiography mammography for breasts with short chest wall to nipple distance

    PubMed Central

    Dong, S L; Su, J L; Yeh, Y H; Chu, T C; Lin, Y C; Chuang, K S

    2011-01-01

    Objective Imaging breasts with a short chest wall to nipple distance (CWND) using a traditional mammographic X-ray unit is a technical challenge for mammographers. The purpose of this study is the development of an imaging-planning program to assist in determination of imaging parameters of screen/film (SF) and computed radiography (CR) mammography for short CWND breasts. Methods A traditional mammographic X-ray unit (Mammomat 3000, Siemens, Munich, Germany) was employed. The imaging-planning program was developed by combining the compressed breast thickness correction, the equivalent polymethylmethacrylate thickness assessment for breasts and the tube loading (mAs) measurement. Both phantom exposures and a total of 597 exposures were used for examining the imaging-planning program. Results Results of the phantom study show that the tube loading rapidly decreased with the CWND when the automatic exposure control (AEC) detector was not fully covered by the phantom. For patient exposures with the AEC fully covered by breast tissue, the average fractional tube loadings, defined as the ratio of the predicted mAs using the imaging-planning program and mAs of the mammogram, were 1.10 and 1.07 for SF and CR mammograms, respectively. The predicted mAs values were comparable to the mAs values, as determined by the AEC. Conclusion By applying the imaging-planning program in clinical practice, the experiential dependence of the mammographer for determination of the imaging parameters for short CWND breasts is minimised. PMID:21123310

  6. SU-E-T-632: A Dosimetric Comparison of the 3D-CRT Planning of Chest Wall in Post-Mastectomy Breast Cancer Patients, with and Without Breast Board Setup

    SciTech Connect

    Muzaffar, Ambreen; Masood, Asif; Ullah, Haseeb; Mehmood, Kashif; Qasim, Uzma; Afridi, M. Ali; Khan, Salim; Hameed, Abdul

    2014-06-15

    Purpose: Breast boards are used in breast radiation which increases normal lung and heart doses, when supraclavicular field is included. Therefore, in this study through dose volume histogram (DVHs), lung and heart doses comparison was done between two different setups i.e. with and without breast board, for the treatment of left chest wall and supraclavicular fossa in postmastectomy left breast cancer. Methods: In this study, CT-Simulation scans of ten breast cancer patients were done with and without breast board, at Shifa International Hospitals Islamabad, to investigate the differences between the two different setups of the irradiation of left chest wall in terms of lung and heart doses. For immobilization, support under the neck, shoulders and arms was used. Precise PLAN 2.15 treatment planning system (TPS) was used for 3D-CRT planning. The total prescribed dose for both the plans was 5000 cGy/25 fractions. The chest wall was treated with a pair of tangential photon fields and the upper supraclavicular nodal regions were treated with an anterior photon field. A mono-isocentric technique was used to match the tangential fields with the anterior field at the isocentre. The dose volume histogram was used to compare the doses of heart and ipsilateral lung. Results: Both the plans of each patient were generated and compared. DVH results showed that for the same PTV dose coverage, plans without breast board resulted in a reduction of lung and heart doses compared with the plans with breast board. There was significant reductions in V20, V<25 and mean doses for lung and V<9 and mean doses for heart. Conclusion: In comparison of both the plans, setup without breast board significantly reduced the dose-volume of the ipsilateral lung and heart in left chest wall patients. Waived registration request has been submitted.

  7. Efficacy and safety of human fibrinogen-thrombin patch (Tachosil®) in the management of diffuse bleeding after chest wall and spinal surgical resection for aggressive thoracic neoplasms

    PubMed Central

    Guerrera, Francesco; Sandri, Alberto; Zenga, Francesco; Lanza, Giovanni Vittorio; Ruffini, Enrico; Bora, Giulia; Lyberis, Paraskevas; Solidoro, Paolo; Oliaro, Alberto

    2016-01-01

    Diffuse bleeding after chest wall and spine resection represents a major problem in General Thoracic Surgery. Several fibrin sealants (FS) have been developed over the years and their use has been gradually increasing over time, becoming an important aid to the surgeons, justifying their use across numerous fields of surgery due to its valid haemostatic properties. Among the several FS available, TachoSil® (Takeda Austria GmbH, Linz, Austria) stands out for its haemostatic and aerostatic properties, the latter being demonstrated even in high-risk patients after pulmonary resections for primary lung cancers. Several papers available in literature demonstrated TachoSil®’s effectiveness in controlling intraoperative and postoperative bleeding in different surgical branches, including hepatic and pancreatic surgery, as well as cardiac and thoracic surgery. However, the use of TachoSil® to control diffuse bleeding following major resections for advanced lung cancers, with requirement of chest wall and vertebral body resection for oncological radicality, was never published so far. In this paper, we report three cases of pulmonary lobectomy associated to chest wall resection and haemivertebrectomy for primary malignant lung neoplasms and for a recurrence of malignant solitary fibrous tumour of the pleura in which we used TachoSil©, which demonstrated its efficacy in controlling diffuse bleeding following resection. PMID:26904247

  8. SU-E-T-583: Operated Left Breast and Chest Wall Radiotherapy: A Dosimetric Comparison Between 3DCRT, IMRT and VMAT

    SciTech Connect

    Sarkar, B; Roy, S; Munshi, A; Pradhan, A

    2015-06-15

    Purpose: To evaluate the comparative dosimetric efficacy between field and field 3DCRT(FnF), multiple field Intensity modulated radiotherapy (SnS IMRT) and, partial arc volumetric modulated arc therapy (VMAT) in case of post operative left side breast and chest wall irradiation. Methods: CT study set of fifteen post-operative left breast and chest wall patient was tested for a treatment plan of 50Gy in 25 fraction using partial arc VMAT, SnSIMRT and tangential beam 3DCRT . 3DCRT FnF gantry angle was ranging for left medial tangential 290±17{sup 0} and Lt lateral tangential l14°±12{sup 0}. For IMRT four fixed beam at gantry angle G130{sup 0} G110{sup 0} G300{sup 0} and G330{sup 0} was used, in case of insufficient dose another beam G150{sup 0} was added. In case of partial arc VMAT, lateral tangential arc G130{sup 0}-G100{sup 0} and medial tangential arc G280{sup 0}-G310{sup 0}. Inverse optimization was opted to cover at least 95%PTV by 95% prescription dose (RxD) and a strong weightage on reduction of heart and lung dose. PTV coverage was evaluated for it’s clinically acceptability depending on the tumor spatial location and its quadrant. Out of the three plans, any one was used for the actual patient treatment. Results: Dosimetric analysis done for breast PTV, left lung, heart and the opposite breast. PTV mean dose and maximum dose was 5129.8±214.8cGy, 4749.0±329.7cGy, 5024.6±73.4cGy and 5855.2±510.7cGy, 5340.7±146.1cGy, 5347.2±196.8cGy for FnF, VMAT and IMRT respectively. Ipsilateral lung volume receiving 20Gy and 5Gy was 23.6±9.5cGy and 32.7±10.3cGy for FnF, 18.6±8.7cGy and 38.8±15.2cGy for VMAT and 25.7±9.6cGy and 50.7±8.4cGy for IMRT respectively. Heart mean and 2cc dose was 867.9±456.7cGy and 5038.5±184.3cGy for FnF, 532.6±263cGy and 3632.1±990.6 for VMAT, 711±229.9cGy and 4421±463.7cGy for IMRT respectively. VMAT shows minimum contralateral breast dose 168±113.8cGy. Conclusion: VMAT shows a better tumor conformity, minimum heart

  9. Chest Wall Volume Receiving >30 Gy Predicts Risk of Severe Pain and/or Rib Fracture After Lung Stereotactic Body Radiotherapy

    SciTech Connect

    Dunlap, Neal E.; Cai, Jing; Biedermann, Gregory B.; Yang, Wensha; Benedict, Stanley H.; Sheng Ke; Schefter, Tracey E.; Kavanagh, Brian D.; Larner, James M.

    2010-03-01

    Purpose: To identify the dose-volume parameters that predict the risk of chest wall (CW) pain and/or rib fracture after lung stereotactic body radiotherapy. Methods and Materials: From a combined, larger multi-institution experience, 60 consecutive patients treated with three to five fractions of stereotactic body radiotherapy for primary or metastatic peripheral lung lesions were reviewed. CW pain was assessed using the Common Toxicity Criteria for pain. Peripheral lung lesions were defined as those located within 2.5 cm of the CW. A minimal point dose of 20 Gy to the CW was required. The CW volume receiving >=20, >=30, >=40, >=50, and >=60 Gy was determined and related to the risk of CW toxicity. Results: Of the 60 patients, 17 experienced Grade 3 CW pain and five rib fractures. The median interval to the onset of severe pain and/or fracture was 7.1 months. The risk of CW toxicity was fitted to the median effective concentration dose-response model. The CW volume receiving 30 Gy best predicted the risk of severe CW pain and/or rib fracture (R{sup 2} = 0.9552). A volume threshold of 30 cm{sup 3} was observed before severe pain and/or rib fracture was reported. A 30% risk of developing severe CW toxicity correlated with a CW volume of 35 cm{sup 3} receiving 30 Gy. Conclusion: The development of CW toxicity is clinically relevant, and the CW should be considered an organ at risk in treatment planning. The CW volume receiving 30 Gy in three to five fractions should be limited to <30 cm{sup 3}, if possible, to reduce the risk of toxicity without compromising tumor coverage.

  10. Postmastectomy Chest Wall Radiation to a Temporary Tissue Expander or Permanent Breast Implant-Is There a Difference in Complication Rates?

    SciTech Connect

    Anderson, Penny R. Freedman, Gary; Nicolaou, Nicos; Sharma, Navesh; Li Tianyu; Topham, Neal; Morrow, Monica

    2009-05-01

    Purpose: The purpose of this study was to evaluate the likelihood of complications and cosmetic results among breast cancer patients who underwent modified radical mastectomy (MRM) and breast reconstruction followed by radiation therapy (RT) to either a temporary tissue expander (TTE) or permanent breast implant (PI). Methods and Materials: Records were reviewed of 74 patients with breast cancer who underwent MRM followed by breast reconstruction and RT. Reconstruction consisted of a TTE usually followed by exchange to a PI. RT was delivered to the TTE in 62 patients and to the PI in 12 patients. Dose to the reconstructed chest wall was 50 Gy. Median follow-up was 48 months. The primary end point was the incidence of complications involving the reconstruction. Results: There was no significant difference in the rate of major complications in the PI group (0%) vs. 4.8% in the TTE group. No patients lost the reconstruction in the PI group. Three patients lost the reconstruction in the TTE group. There were excellent/good cosmetic scores in 90% of the TTE group and 80% of the PI group (p = 0.22). On multivariate regression models, the type of reconstruction irradiated had no statistically significant impact on complication rates. Conclusions: Patients treated with breast reconstruction and RT can experience low rates of major complications. We demonstrate no significant difference in the overall rate of major or minor complications between the TTE and PI groups. Postmastectomy RT to either the TTE or the PI should be considered as acceptable treatment options in all eligible patients.

  11. SPECT Analysis of Cardiac Perfusion Changes After Whole-Breast/Chest Wall Radiation Therapy With or Without Active Breathing Coordinator: Results of a Randomized Phase 3 Trial

    SciTech Connect

    Zellars, Richard; Bravo, Paco E.; Tryggestad, Erik; Hopfer, Kari; Myers, Lee; Tahari, Abdel; Asrari, Fariba; Ziessman, Harvey; Garrett-Mayer, Elizabeth

    2014-03-15

    Purpose: Cardiac muscle perfusion, as determined by single-photon emission computed tomography (SPECT), decreases after breast and/or chest wall (BCW) irradiation. The active breathing coordinator (ABC) enables radiation delivery when the BCW is farther from the heart, thereby decreasing cardiac exposure. We hypothesized that ABC would prevent radiation-induced cardiac toxicity and conducted a randomized controlled trial evaluating myocardial perfusion changes after radiation for left-sided breast cancer with or without ABC. Methods and Materials: Stages I to III left breast cancer patients requiring adjuvant radiation therapy (XRT) were randomized to ABC or No-ABC. Myocardial perfusion was evaluated by SPECT scans (before and 6 months after BCW radiation) using 2 methods: (1) fully automated quantitative polar mapping; and (2) semiquantitative visual assessment. The left ventricle was divided into 20 segments for the polar map and 17 segments for the visual method. Segments were grouped by anatomical rings (apical, mid, basal) or by coronary artery distribution. For the visual method, 2 nuclear medicine physicians, blinded to treatment groups, scored each segment's perfusion. Scores were analyzed with nonparametric tests and linear regression. Results: Between 2006 and 2010, 57 patients were enrolled and 43 were available for analysis. The cohorts were well matched. The apical and left anterior descending coronary artery segments had significant decreases in perfusion on SPECT scans in both ABC and No-ABC cohorts. In unadjusted and adjusted analyses, controlling for pretreatment perfusion score, age, and chemotherapy, ABC was not significantly associated with prevention of perfusion deficits. Conclusions: In this randomized controlled trial, ABC does not appear to prevent radiation-induced cardiac perfusion deficits.

  12. Is there a standard of care for the radical management of non-small cell lung cancer involving the apical chest wall (Pancoast tumours)?

    PubMed

    Peedell, C; Dunning, J; Bapusamy, A

    2010-06-01

    The term Pancoast tumour encompasses a wide range of tumours that invade the apical chest wall. Although less than 5% of non-small cell lung cancers are Pancoast tumours, they still account for most cases. They often pose a formidable challenge to the multidisciplinary lung cancer team due to their relative rarity, anatomical proximity to vital structures, differing stages of presentation, and their association with smoking-related illnesses. A lack of clinical trials makes comparisons between different treatment modalities very difficult and the management of Pancoast tumours has been largely based on the published retrospective experience of large single institutions. The bimodality approach of induction radiotherapy followed by surgical resection has been the accepted standard of care for the last 50 years, with reported 5-year survival rates of 30% in selected patients. However, two recent prospective multicentre phase II studies using a trimodality approach of induction concurrent chemoradiotherapy followed by surgical resection (followed by two further cycles of adjuvant chemotherapy in one of the studies), have reported 5-year survival rates of 44-56%. This has led to some authorities advocating the trimodality approach as the new standard of care for the management of Pancoast tumours. In this overview, the historical evolution of the management of Pancoast tumours and recent published studies on the trimodality approach are discussed. This is followed by a discussion of whether the trimodality approach should be seen as a new standard of care. Finally, other potential treatment options and the possibilities for future research are deliberated. PMID:20347280

  13. Early Detection of Cervical Intraepitelial Neoplasia in a Heterogeneos Group of Colombian Women Using Electrical Impedance Spectroscopy and the Miranda-López Algorithm

    NASA Astrophysics Data System (ADS)

    Miranda, David A.; Corzo, Sandra P.; González-Correa, Carlos-A.

    2012-12-01

    Electrical Impedance Spectroscopy (EIS) allows the study of the electrical properties of materials and structures such as biological tissues. EIS can be used as a diagnostic tool for the identification of pathological conditions such as cervical cancer. We used EIS in combination with genetic algorithms to characterize cervical epithelial squamous tissue in a heterogeneous sample of 56 Colombian women. All volunteers had a cytology taken for Papanicolau test and biopsy taken for histopathological analysis from those with a positive result (9 subjects). ROC analysis of the results suggest a sensitivity and specificity in the order of 0.73 and 0.86, respectively.

  14. Radiation-induced low-grade fibromyxoid sarcoma of the chest wall nine years subsequent to radiotherapy for breast carcinoma: A case report

    PubMed Central

    SHIBATA, SHINO; SHIRAISHI, KENSHIRO; YAMASHITA, HIDEOMI; KOBAYASHI, REIKO; NAKAGAWA, KEIICHI

    2016-01-01

    The present study reports a case of low-grade fibromyxoid sarcoma that occurred in a 62-year-old woman 9 years subsequent to whole breast irradiation for a carcinoma of the left breast, and 18 years following chemotherapy and radiotherapy (RT) for non-Hodgkin's lymphoma (NHL; diagnosed at the age of 43). The patient was 53 years of age when a cT2N0M0 stage IIA breast tumor was identified and excised. A 2.5 cm diameter nodule with dimpling in the upper-outer region of the left breast was detected. Pathological examination revealed that the tumor was an invasive ductal carcinoma, of a solid tubular type. The patient was treated with post-surgical whole breast RT. The left breast received 46 Gy in 23 fractions (2 Gy per fraction) for 4 weeks and 3 days, followed by a cone down boost of 14 Gy in 7 fractions (2 Gy per fraction); therefore a total dose of 60 Gy in 30 fractions was administered. In total, 9 years subsequent to RT, the patient observed a small lump in the left chest wall. The patient underwent excision of the tumor and pectoralis major fascia. Microscopically, the tumor consisted of atypical spindle cells with myxoid stroma. Pathologists concluded that the tumor was a low-grade fibromyxoid sarcoma. Since the tumor developed from tissue in a previously irradiated region, it was considered to be RT-induced, and was classified using the radiation-induced sarcoma (RIS) criteria as dictated by Cahan. Although the majority of RIS cases are angiosarcomas, a rare, low-grade fibromyxoid sarcoma was observed in the present study. The present study hypothesizes that there may have been an overlap region between the RT for supraclavicular nodes of NHL and the whole breast RT for primary breast cancer, due to the results of a retrospective dose reconstruction undertaken by the present study. The patient remained clinically stable for 4 years thereafter, until 2008 when the patient experienced a local relapse and underwent surgery. On 19 October 2011, the patient

  15. Evaluation of bolus electron conformal therapy compared with conventional techniques for the treatment of left chest wall postmastectomy in patients with breast cancer

    SciTech Connect

    Opp, Dan Forster, Kenneth; Li, Weiqi; Zhang, Geoffrey; Harris, Eleanor E.

    2013-01-01

    Postmastectomy radiation (PMRT) lowers local-regional recurrence risk and improves survival in selected patients with breast cancer. The chest wall and lower axilla are technically challenging areas to treat with homogenous doses and normal tissue sparing. This study compares several techniques for PMRT to provide data to guide selection of optimal treatment techniques. Twenty-five consecutive left-sided patients treated postmastectomy were contoured using Radiation Therapy Oncology Group (RTOG) atlas guidelines then planned using 4 different PMRT techniques: opposed tangents with wedges (3-dimensional [3D] wedges), opposed tangents with field-in-field (FiF) modulation, 8-field intensity modulation radiotherapy (IMRT), and custom bolus electron conformal therapy (BolusECT, .decimal, Inc., Sanford, FL). Required planning target volume (PTV) coverage was held constant, and then dose homogeneity and normal tissue dose parameters were compared among the 4 techniques. BolusECT achieved clincally acceptable PTV coverage for 22 out of 25 cases. Compared with either tangential technique, IMRT and BolusECT provided the lowest heart V{sub 25} doses (3.3% ± 0.9% and 6.6% ± 3.2%, respectively with p < 0.0001). FiF had the lowest mean total lung dose (7.3 ± 1.1 Gy, with p = 0.0013), IMRT had the lowest total lung V{sub 20} (10.3% ± 1.6%, p < 0.0001), and BolusECT had the lowest mean heart dose (7.3 ± 2.0 Gy, p = 0.0002). IMRT provided the optimal dose homogeneity and normal tissue sparing compared with all other techniques for the cases in which BolusECT could not achieve acceptable PTV coverage. IMRT generally exposes contralateral breast and lung to slightly higher doses. Optimal PMRT technique depends upon patient anatomy. Patients whose maximal target volume depth is about 5.7 cm or less can be treated with BolusECT-assisted 12 or 15 MeV electron beams. At these energies, BolusECT has comparable dose-volume statistics as IMRT and lower heart V{sub 25} than opposed

  16. Computer simulation of respiratory impedance and flow transfer functions during high frequency oscillations.

    PubMed

    Peslin, R

    1989-01-01

    The usefulness of measuring respiratory flow in the airway and at the chest wall and of measuring respiratory input impedance (Z) to monitor high frequency ventilation was investigated by computer simulation using a monoalveolar 10-coefficient model. The latter included a central airway with its resistance (Rc) and inertance (lc), a resistive peripheral airway (Rp), a lumped bronchial compliance (Cb), alveolar gas compliance (Cgas), lung tissue with its resistance (RL) and compliance (CL), and chest wall resistance (RW), inertance (lw) and compliance (Cw). Gas flow in the peripheral airway (Vp), shunt flow through Cb (Vb), gas compression flow (Vgas) and rate of volume change of the lung (VL) and of the chest (VW) were computed and expressed as a function of gas flow in the central airway (Vc). For normal values of the coefficients, Vp/Vc was found to decrease moderately with increasing frequency and was still 0.75 at 20 Hz. Peripheral airway obstruction (Rp x 5) considerably decreased Vp/Vc, particularly at high frequency. It did not change the relationship between the two measurable flows, Vc and Vw, but increased the effective resistance at low frequency and shifted the reactance curve to the right. A reduced lung or chest wall compliance produced little change in Vp/Vc and Z except at very low frequencies; however, it decreased the phase lag between Vw and Vc. Finally, an increased airway wall compliance decreased Vp/Vc, but had little effect on Z and Vw/Vc. It is concluded that measuring respiratory impedance may help in detecting some, but not all of the conditions in which peripheral flow convection is decreased during high frequency oscillations. PMID:2611083

  17. Electron Impedances

    SciTech Connect

    P Cameron

    2011-12-31

    It is only recently, and particularly with the quantum Hall effect and the development of nanoelectronics, that impedances on the scale of molecules, atoms and single electrons have gained attention. In what follows the possibility that characteristic impedances might be defined for the photon and the single free electron is explored is some detail, the premise being that the concepts of electrical and mechanical impedances are relevant to the elementary particle. The scale invariant quantum Hall impedance is pivotal in this exploration, as is the two body problem and Mach's principle.

  18. Secondary reconstruction with a transverse colon covered with a pectoralis major muscle flap and split thickness skin grafts for an esophageal defect and wide skin defects of the anterior chest wall.

    PubMed

    Sadanaga, Noriaki; Morinaga, Keigo; Matsuura, Hiroshi

    2015-12-01

    Necrosis of a reconstructed organ after esophagectomy is a rare postoperative complication. However, in case this complication develops, severe infectious complications can occur, and subsequent surgical reconstruction is quite complicated. To treat esophageal conduit necrosis after esophageal reconstruction with the terminal ileum and ascending colon, we reconstructed the esophagus using a transverse colon, which was covered with a pectoralis major muscle flap to reinforce the anastomotic site. In addition, split thickness skin grafts were applied to the wide skin defect to cover the reconstructed organs at the antesternal route. Widely extended split thickness skin grafts can adhere to the reconstructed organs without excessive tension. Therefore, this method enabled successful treatment of an esophageal defect and wide skin defects of the anterior chest wall. PMID:26943390

  19. Diastolic timed Vibro-Percussion at 50 Hz delivered across a chest wall sized meat barrier enhances clot dissolution and remotely administered Streptokinase effectiveness in an in-vitro model of acute coronary thrombosis

    PubMed Central

    2012-01-01

    Background Low Frequency Vibro-Percussion (LFVP) assists clearance of thrombi in catheter systems and when applied to the heart and timed to diastole is known to enhance coronary flow. However LFVP on a clotted coronary like vessel given engagement over a chest wall sized barrier (to resemble non-invasive heart attack therapy) requires study. Methods One hour old clots (n=16) were dispensed within a flexible segment of Soft-Flo catheter (4 mm lumen), weighted, interfaced with Heparinized Saline (HS), secured atop a curved dampening base, and photographed. A ~4 cm meat slab was placed over the segment and randomized to receive intermittent LFVP (engaged, - disengaged at 1 second intervals), or no LFVP for 20 minutes. HS was pulsed (~120/80 mmHg), with the diastolic phase coordinated to match LFVP delivery. The segment was then re-photographed and aspirated of fluid to determine post clot weight. The trial was then repeated with 0.5 mls of Streptokinase (15,000 IU/100 microlitre) delivered ~ 2 cm upstream from the clot. Results LFVP - HS only samples (vs. controls) showed; a) development of clot length fluid channels absent in the control group (p < 0.0002); b) enhanced dissolved clot mixing scores ( 5.0 vs. 0.8, p < 2.8 E – 6); and c) increased percent clot dissolution (23.0% vs. 1.8% respectively, p < 8.5 E-6). LFVP - SK samples had a similar comparative clot disruptive profile, however fluid channels developed faster and percent clot dissolution more than doubled (51.0% vs. 3.0%, p< 9.8 E- 6). Conclusion Diastolic timed LFVP (50 Hz) engaged across a chest wall sized barrier enhances clot disruptive effects to an underlying coronary like system. PMID:23146079

  20. Acute clinical benefits of chest wall-stretching exercise on expired tidal volume, dyspnea and chest expansion in a patient with chronic obstructive pulmonary disease: a single case study.

    PubMed

    Leelarungrayub, Donrawee; Pothongsunun, Prapas; Yankai, Araya; Pratanaphon, Sainatee

    2009-10-01

    Chest physical therapy (CPT) has an important role in a medical team to assist in resolving the critical problems deriving from chronic lung disease. These critical problems include increased secretion volume, difficult breathing or dyspnea, ineffective coughing, inability to be weaned off a ventilator, and physical deterioration resulting from low aerobic capacity and endurance after prolonged bed rest. The inability to be weaned off a ventilator does not only result from secretion production or muscle weakness, but other conditions including chest stiffness or immobility. The procedure to increase chest mobility includes specific chest stretching and mobilization. Chest wall-stretching exercises were composed of thoracic rotation and anterior compression with stretching in sitting position, trunk extension and rib torsion in supine lying, and lateral stretching in side lying. These exercises were given to the patient as a regular daily program along with postural drainage, percussion, breathing exercise and limb exercises. The expired tidal volume, dyspnea level, and chest expansion were evaluated and clinical efficiency was analyzed during CPT, compared to Pre-CPT and Post-CPT with Bloom table. The results showed a significant clinical improvement of expired tidal volume, reduction in dyspnea level, and increase in chest expansion. PMID:19761957

  1. Electromagnetic scattering by impedance structures

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Griesser, Timothy

    1987-01-01

    The scattering of electromagnetic waves from impedance structures is investigated, and current work on antenna pattern calculation is presented. A general algorithm for determining radiation patterns from antennas mounted near or on polygonal plates is presented. These plates are assumed to be of a material which satisfies the Leontovich (or surface impedance) boundary condition. Calculated patterns including reflection and diffraction terms are presented for numerious geometries, and refinements are included for antennas mounted directly on impedance surfaces. For the case of a monopole mounted on a surface impedance ground plane, computed patterns are compared with experimental measurements. This work in antenna pattern prediction forms the basis of understanding of the complex scattering mechanisms from impedance surfaces. It provides the foundation for the analysis of backscattering patterns which, in general, are more problematic than calculation of antenna patterns. Further proposed study of related topics, including surface waves, corner diffractions, and multiple diffractions, is outlined.

  2. Effect of acceleration on the chest wall.

    PubMed

    Wilson, T A; Liu, S

    1994-03-01

    The gravitational force on the rib cage has been found to be an expiratory force of approximately 8 cmH2O. The gravitational force on the abdomen is an inspiratory force of the same magnitude. Because the compliance of the rib cage is greater than the compliance of the abdomen, it follows that gravity has a net expiratory effect on lung volume and that upward accelerations augmenting the gravitational force would have an additional expiratory effect. This conclusion is contrary to observations that functional residual capacity increases during headward accelerations in centrifuges and during intervals of upward acceleration in airplanes. We report the results of two studies of the effects of accelerations that are smaller in magnitude and of shorter duration than those studied in centrifuges and airplanes. The first was an experimental study of the effect of acceleration in an elevator. In subjects who relaxed against an occluded airway, airway pressure increased during upward accelerations and decreased during downward accelerations. The second was the modeling and analysis of the effects of the accelerations that occur during walking. The analysis predicted an initial expiratory response to the acceleration spike that occurs during footfall. The prediction agreed with data in the literature on the respiratory effect of walking. In both of these studies upward accelerations had an expiratory effect. PMID:8005868

  3. Impedance magnetocardiogram.

    PubMed

    Kandori, A; Miyashita, T; Suzuki, D; Yokosawa, K; Tsukada, K

    2001-02-01

    We have developed an impedance magnetocardiogram (IMCG) system to detect the change of magnetic field corresponding to changes in blood volume in the heart. A low magnetic field from the electrical activity of the human heart--the so-called magnetocardiogram (MCG)--can be simultaneously detected by using this system. Because the mechanical and electrical functions in the heart can be monitored by non-invasive and non-contact measurements, it is easy to observe the cardiovascular functions from an accurate sensor position. This system uses a technique to demodulate induced current in a subject. A flux-locked circuit of a superconducting quantum interference device has a wide frequency range (above 1 MHz) because a constant current (40 kHz) is fed through the subject. It is shown for the first time that the system could measure IMCG signals at the same time as MCG signals. PMID:11229740

  4. Dosimetric comparison for volumetric modulated arc therapy and intensity-modulated radiotherapy on the left-sided chest wall and internal mammary nodes irradiation in treating post-mastectomy breast cancer

    PubMed Central

    Zhang, Qian; Yu, Xiao Li; Hu, Wei Gang; Chen, Jia Yi; Wang, Jia Zhou; Ye, Jin Song; Guo, Xiao Mao

    2015-01-01

    Background The aim of the study was to evaluate the dosimetric benefit of applying volumetric modulated arc therapy (VMAT) on the post-mastectomy left-sided breast cancer patients, with the involvement of internal mammary nodes (IMN). Patients and methods The prescription dose was 50 Gy delivered in 25 fractions, and the clinical target volume included the left chest wall (CW) and IMN. VMAT plans were created and compared with intensity-modulated radiotherapy (IMRT) plans on Pinnacle treatment planning system. Comparative endpoints were dose homogeneity within planning target volume (PTV), target dose coverage, doses to the critical structures including heart, lungs and the contralateral breast, number of monitor units and treatment delivery time. Results VMAT and IMRT plans showed similar PTV dose homogeneity, but, VMAT provided a better dose coverage for IMN than IMRT (p = 0.017). The mean dose (Gy), V30 (%) and V10 (%) for the heart were 13.5 ± 5.0 Gy, 9.9% ± 5.9% and 50.2% ± 29.0% by VMAT, and 14.0 ± 5.4 Gy, 10.6% ± 5.8% and 55.7% ± 29.6% by IMRT, respectively. The left lung mean dose (Gy), V20 (%), V10 (%) and the right lung V5 (%) were significantly reduced from 14.1 ± 2.3 Gy, 24.2% ± 5.9%, 42.4% ± 11.9% and 41.2% ± 12.3% with IMRT to 12.8 ± 1.9 Gy, 21.0% ± 3.8%, 37.1% ± 8.4% and 32.1% ± 18.2% with VMAT, respectively. The mean dose to the contralateral breast was 1.7 ± 1.2 Gy with VMAT and 2.3 ± 1.6 Gy with IMRT. Finally, VMAT reduced the number of monitor units by 24% and the treatment time by 53%, as compared to IMRT. Conclusions Compared to 5-be am step-and-shot IMRT, VMAT achieves similar or superior target coverage and a better normal tissue sparing, with fewer monitor units and shorter delivery time. PMID:25810708

  5. Adaptive Impedance Control Of Redundant Manipulators

    NASA Technical Reports Server (NTRS)

    Seraji, Homayoun; Colbaugh, Richard D.; Glass, Kristin L.

    1994-01-01

    Improved method of controlling mechanical impedance of end effector of redundant robotic manipulator based on adaptive-control theory. Consists of two subsystems: adaptive impedance controller generating force-control inputs in Cartesian space of end effector to provide desired end-effector-impedance characteristics, and subsystem implementing algorithm that maps force-control inputs into torques applied to joints of manipulator. Accurate control of end effector and effective utilization of redundancy achieved simultaneously by use of method. Potential use to improve performance of such typical impedance-control tasks as deburring edges and accommodating transitions between unconstrained and constrained motions of end effectors.

  6. Total respiratory impedance measurement by forced oscillations: a noninvasive method to assess bronchial response in occupational medicine.

    PubMed

    Wouters, E F

    1990-01-01

    The forced oscillation technique is a noninvasive and effort-independent test to characterize the mechanical impedance of the respiratory system. By applying a complex signal, the frequency-dependent behavior of the respiratory system can be measured over an extended spectrum. For clinical practice, the input impedance is used most frequently; pressure and flow are measured at the same place. The impedance can be partitioned into a real part or resistance and an imaginary part or reactance. At low frequencies, reactance is determined by the capacitance of the system and at high frequencies by the inertial properties of the system. Equipment and impedance data in normal subjects and patients with chronic obstructive pulmonary disease are discussed. The frequency-dependent behavior of the respiratory system is described with the use of an electrical model characterized by partitioning of airway resistance and the presence of shunt compliance represented by the compliance of the intrathoracic airway walls. Influences of peripheral resistance, airway compliance, lung volumes, chest wall and pulmonary resistance, and resistance of the cheeks and upper airways are analyzed. Input impedance can be applied to the detection of bronchoconstriction and bronchodilation, but this technique is suitable for detecting early airway abnormalities caused by smoking or occupational hazards. PMID:2307147

  7. ADVANCES IN IMPEDANCE THEORY

    SciTech Connect

    Stupakov, G.; /SLAC

    2009-06-05

    We review recent progress in the following areas of the impedance theory: calculation of impedance of tapers and small angle collimators; optical approximation and parabolic equation for the high-frequency impedance; impedance due to resistive inserts in a perfectly conducting pipe.

  8. Influence of cheek support on respiratory impedance measured by forced oscillation technique.

    PubMed

    Uchida, Akemi; Ito, Satoru; Suki, Béla; Matsubara, Hiroki; Hasegawa, Yoshinori

    2013-01-01

    The forced oscillation technique (FOT) is a useful tool to assess respiratory resistance and reactance during tidal breathing in patients with respiratory diseases, specifically asthma and chronic obstructive pulmonary disease. Although the FOT has been clinically used, results of respiratory impedance can be affected by various factors such as upper airway artifact. We investigated the effects of cheek support on respiratory resistance and reactance measured by a commercially available FOT equipment MostGraph-01. Respiratory resistance at 20 Hz (R20) with support of the cheeks was significantly higher than those without the cheek support in healthy subjects. Two different cheek support protocols, support of the cheeks by subjects themselves and an operator, were compared in healthy volunteers and patients with respiratory diseases. The cheek support protocols significantly affected respiratory resistance at 5 Hz (R5) and reactance at 5 Hz (X5) in the patient group but not in the healthy subjects. Moreover, for X5, there was a significant interaction between cheek support protocols (by a subject or operator) and groups (healthy or diseased). In conclusion, during impedance measurements using the FOT, application of cheek support either by subjects or the operator is recommended to reduce upper airway artifacts, however, results obtained by two protocols may be different in patients with respiratory diseases. Contribution of the chest wall and position of the arms to the mechanical properties should be carefully considered in physiological studies in which the FOT is attempted. PMID:23961407

  9. Impedance based automatic electrode positioning.

    PubMed

    Miklody, Daniel; Hohne, Johannes

    2015-08-01

    The position of electrodes in electrical imaging and stimulation of the human brain is an important variable with vast influences on the precision in modeling approaches. Nevertheless, the exact position is obscured by many factors. 3-D Digitization devices can measure the distribution over the scalp surface but remain uncomfortable in application and often imprecise. We demonstrate a new approach that uses solely the impedance information between the electrodes to determine the geometric position. The algorithm involves multidimensional scaling to create a 3 dimensional space based on these impedances. The success is demonstrated in a simulation study. An average electrode position error of 1.67cm over all 6 subjects could be achieved. PMID:26736345

  10. Robust impedance shaping telemanipulation

    SciTech Connect

    Colgate, J.E.

    1993-08-01

    When a human operator performs a task via a bilateral manipulator, the feel of the task is embodied in the mechanical impedance of the manipulator. Traditionally, a bilateral manipulator is designed for transparency; i.e., so that the impedance reflected through the manipulator closely approximates that of the task. Impedance shaping bilateral control, introduced here, differs in that it treats the bilateral manipulator as a means of constructively altering the impedance of a task. This concept is particularly valuable if the characteristic dimensions (e.g., force, length, time) of the task impedance are very different from those of the human limb. It is shown that a general form of impedance shaping control consists of a conventional power-scaling bilateral controller augmented with a real-time interactive task simulation (i.e., a virtual environment). An approach to impedance shaping based on kinematic similarity between tasks of different scale is introduced and illustrated with an example. It is shown that an important consideration in impedance shaping controller design is robustness; i.e., guaranteeing the stability of the operator/manipulator/task system. A general condition for the robustness of a bilateral manipulator is derived. This condition is based on the structured singular value ({mu}). An example of robust impedance shaping bilateral control is presented and discussed.

  11. Rotor damage detection by using piezoelectric impedance

    NASA Astrophysics Data System (ADS)

    Qin, Y.; Tao, Y.; Mao, Y. F.

    2016-04-01

    Rotor is a core component of rotary machinery. Once the rotor has the damage, it may lead to a major accident. Thus the quantitative rotor damage detection method based on piezoelectric impedance is studied in this paper. With the governing equation of piezoelectric transducer (PZT) in a cylindrical coordinate, the displacement along the radius direction is derived. The charge of PZT is calculated by the electric displacement. Then, by the use of the obtained displacement and charge, an analytic piezoelectric impedance model of the rotor is built. Given the circular boundary condition of a rotor, annular elements are used as the analyzed objects and spectral element method is used to set up the damage detection model. The Electro-Mechanical (E/M) coupled impedance expression of an undamaged rotor is deduced with the application of a low-cost impedance test circuit. A Taylor expansion method is used to obtain the approximate E/M coupled impedance expression for the damaged rotor. After obtaining the difference between the undamaged and damaged rotor impedance, a rotor damage detection method is proposed. This method can directly calculate the change of bending stiffness of the structural elements, it follows that the rotor damage can be effectively detected. Finally, a preset damage configuration is used for the numerical simulation. The result shows that the quantitative damage detection algorithm based on spectral element method and piezoelectric impedance proposed in this paper can identify the location and the severity of the damaged rotor accurately.

  12. Impedance of a nanoantenna

    SciTech Connect

    Greffet, Jean-Jacques; Laroche, Marine; Marquier, Francois

    2009-10-07

    We introduce a generalized definition of the impedance of a nanoantenna that can be applied to any system. We also introduce a definition of the impedance of a two level system. Using this framework, we establish a link between the electrical engineering and the quantum optics picture of light emission.

  13. Overview Of Impedance Sensors

    NASA Astrophysics Data System (ADS)

    Abele, John E.

    1989-08-01

    Electrical impedance has been one of the many "tools of great promise" that physicians have employed in their quest to measure and/or monitor body function or physiologic events. So far, the expectations for its success have always exceeded its performance. In simplistic terms, physiologic impedance is a measure of the resistance in the volume between electrodes which changes as a function of changes in that volume, the relative impedance of that volume, or a combination of these two. The history and principles of electrical impedance are very nicely reviewed by Geddes and Baker in their textbook "Principles of Applied Biomedical Instrumentation". It is humbling, however, to note that Cremer recorded variations in electrical impedance in frog hearts as early as 1907. The list of potential applications includes the measurement of thyroid function, estrogen activity, galvanic skin reflex, respiration, blood flow by conductivity dilution, nervous activity and eye movement. Commercial devices employing impedance have been and are being used to measure respiration (pneumographs and apneamonitors), pulse volume (impedance phlebographs) and even noninvasive cardiac output.

  14. Microfabricated AC impedance sensor

    DOEpatents

    Krulevitch, Peter; Ackler, Harold D.; Becker, Frederick; Boser, Bernhard E.; Eldredge, Adam B.; Fuller, Christopher K.; Gascoyne, Peter R. C.; Hamilton, Julie K.; Swierkowski, Stefan P.; Wang, Xiao-Bo

    2002-01-01

    A microfabricated instrument for detecting and identifying cells and other particles based on alternating current (AC) impedance measurements. The microfabricated AC impedance sensor includes two critical elements: 1) a microfluidic chip, preferably of glass substrates, having at least one microchannel therein and with electrodes patterned on both substrates, and 2) electrical circuits that connect to the electrodes on the microfluidic chip and detect signals associated with particles traveling down the microchannels. These circuits enable multiple AC impedance measurements of individual particles at high throughput rates with sufficient resolution to identify different particle and cell types as appropriate for environmental detection and clinical diagnostic applications.

  15. Wavelet analysis of the impedance cardiogram waveforms

    NASA Astrophysics Data System (ADS)

    Podtaev, S.; Stepanov, R.; Dumler, A.; Chugainov, S.; Tziberkin, K.

    2012-12-01

    Impedance cardiography has been used for diagnosing atrial and ventricular dysfunctions, valve disorders, aortic stenosis, and vascular diseases. Almost all the applications of impedance cardiography require determination of some of the characteristic points of the ICG waveform. The ICG waveform has a set of characteristic points known as A, B, E ((dZ/dt)max) X, Y, O and Z. These points are related to distinct physiological events in the cardiac cycle. Objective of this work is an approbation of a new method of processing and interpretation of the impedance cardiogram waveforms using wavelet analysis. A method of computer thoracic tetrapolar polyrheocardiography is used for hemodynamic registrations. Use of original wavelet differentiation algorithm allows combining filtration and calculation of the derivatives of rheocardiogram. The proposed approach can be used in clinical practice for early diagnostics of cardiovascular system remodelling in the course of different pathologies.

  16. Impedance of accelerator components

    SciTech Connect

    Corlett, J.N.

    1996-05-01

    As demands for high luminosity and low emittance particle beams increase, an understanding of the electromagnetic interaction of these beams with their vacuum chamber environment becomes more important in order to maintain the quality of the beam. This interaction is described in terms of the wake field in time domain, and the beam impedance in frequency domain. These concepts are introduced, and related quantities such as the loss factor are presented. The broadband Q = 1 resonator impedance model is discussed. Perturbation and coaxial wire methods of measurement of real components are reviewed.

  17. Superconducting active impedance converter

    DOEpatents

    Ginley, D.S.; Hietala, V.M.; Martens, J.S.

    1993-11-16

    A transimpedance amplifier for use with high temperature superconducting, other superconducting, and conventional semiconductors allows for appropriate signal amplification and impedance matching to processing electronics. The amplifier incorporates the superconducting flux flow transistor into a differential amplifier configuration which allows for operation over a wide temperature range, and is characterized by high gain, relatively low noise, and response times less than 200 picoseconds over at least a 10-80 K. temperature range. The invention is particularly useful when a signal derived from either far-IR focal plane detectors or from Josephson junctions is to be processed by higher signal/higher impedance electronics, such as conventional semiconductor technology. 12 figures.

  18. Superconducting active impedance converter

    DOEpatents

    Ginley, David S.; Hietala, Vincent M.; Martens, Jon S.

    1993-01-01

    A transimpedance amplifier for use with high temperature superconducting, other superconducting, and conventional semiconductor allows for appropriate signal amplification and impedance matching to processing electronics. The amplifier incorporates the superconducting flux flow transistor into a differential amplifier configuration which allows for operation over a wide temperature range, and is characterized by high gain, relatively low noise, and response times less than 200 picoseconds over at least a 10-80 K. temperature range. The invention is particularly useful when a signal derived from either far-IR focal plane detectors or from Josephson junctions is to be processed by higher signal/higher impedance electronics, such as conventional semiconductor technology.

  19. Impedance cardiography: recent advancements.

    PubMed

    Cybulski, Gerard; Strasz, Anna; Niewiadomski, Wiktor; Gąsiorowska, Anna

    2012-01-01

    The aim of this paper is the presentation of recent advancements in impedance cardiography regarding methodical approach, applied equipment and clinical or research implementations. The review is limited to the papers which were published over last 17 months (dated 2011 and 2012) in well recognised scientific journals. PMID:23042327

  20. Impedances of Tevatron separators

    SciTech Connect

    K. Y. Ng

    2003-05-28

    The impedances of the Tevatron separators are revisited and are found to be negligibly small in the few hundred MHz region, except for resonances at 22.5 MHz. The later are contributions from the power cables which may drive head-tail instabilities if the bunch is long enough.

  1. Longitudinal impedance of RHIC

    SciTech Connect

    Blaskiewicz, M.; Brennan, J. M.; Mernick, K.

    2015-05-03

    The longitudinal impedance of the two RHIC rings has been measured using the effect of potential well distortion on longitudinal Schottky measurements. For the blue RHIC ring Im(Z/n) = 1.5±0.2Ω. For the yellow ring Im(Z/n) = 5.4±1Ω.

  2. Validation of an Impedance Education Method in Flow

    NASA Technical Reports Server (NTRS)

    Watson, Willie R.; Jones, Michael G.; Parrott, Tony L.

    2004-01-01

    This paper reports results of a research effort to validate a method for educing the normal incidence impedance of a locally reacting liner, located in a grazing incidence, nonprogressive acoustic wave environment with flow. The results presented in this paper test the ability of the method to reproduce the measured normal incidence impedance of a solid steel plate and two soft test liners in a uniform flow. The test liners are known to be locally react- ing and exhibit no measurable amplitude-dependent impedance nonlinearities or flow effects. Baseline impedance spectra for these liners were therefore established from measurements in a conventional normal incidence impedance tube. A key feature of the method is the expansion of the unknown impedance function as a piecewise continuous polynomial with undetermined coefficients. Stewart's adaptation of the Davidon-Fletcher-Powell optimization algorithm is used to educe the normal incidence impedance at each Mach number by optimizing an objective function. The method is shown to reproduce the measured normal incidence impedance spectrum for each of the test liners, thus validating its usefulness for determining the normal incidence impedance of test liners for a broad range of source frequencies and flow Mach numbers. Nomenclature

  3. Recycler short kicker beam impedance

    SciTech Connect

    Crisp, Jim; Fellenz, Brian; /Fermilab

    2009-07-01

    Measured longitudinal and calculated transverse beam impedance is presented for the short kicker magnets being installed in the Fermilab Recycler. Fermi drawing number ME-457159. The longitudinal impedance was measured with a stretched wire and the Panofsky equation was used to estimate the transverse impedance. The impedance of 3319 meters (the Recycler circumference) of stainless vacuum pipe is provided for comparison. Although measurements where done to 3GHz, impedance was negligible above 30MHz. The beam power lost to the kicker impedance is shown for a range of bunch lengths. The measurements are for one kicker assuming a rotation frequency of 90KHz. Seven of these kickers are being installed.

  4. Comparison of commercially available three-dimensional treatment planning algorithms for monitor unit calculations in the presence of heterogeneities.

    PubMed

    Butts, J R; Foster, A E

    2001-01-01

    This study uses an anthropomorphic phantom and its computed tomography (CT) data set to evaluate monitor unit (MU) calculations using the CMS Focus Clarkson, the CMS Focus Multigrid Superposition Model, the CMS Focus FFT Convolution Model, and the ADAC Pinnacle Collapsed Cone Convolution Superposition Algorithms. Using heterogeneity corrections, a treatment plan and corresponding MU calculations were generated for several typical clinical situations. A diode detector, placed in an anthropomorphic phantom, was used to compare the treatment planning algorithms' predicted doses with measured data. Differences between diode measurements and the algorithms' calculations were within reasonable levels of acceptability as recommended by Van Dyk et al. [Int. J. Rad. Onc. Biol. Phys. 26, 261-273 (1993)], except for the CMS Clarkson algorithm, which predicted too few MU for delivery of the intended dose to chest wall fields. PMID:11674836

  5. Staging algorithm for diffuse malignant pleural mesothelioma.

    PubMed

    Zielinski, Marcin; Hauer, Jolanta; Hauer, Lukasz; Pankowski, Juliusz; Nabialek, Tomasz; Szlubowski, Artur

    2010-02-01

    An algorithm of preoperative mediastinal nodal staging with endobronchial/endoesophageal ultrasonography (EBUS/EUS) and transcervical extended mediastinal lymphadenectomy (TEMLA) combined with laparoscopy/peritoneal lavage and cytology was analyzed to establish the realistic criteria for radical multimodality treatment of malignant pleural mesothelioma (MPM). The algorithm included computed tomography (CT), thoracoscopy with multiple pleural biopsies and talc pleurodesis, EBUS/EUS and one-stage TEMLA and laparoscopy/peritoneal lavage and cytology of the fluid. Forty-two patients were diagnosed from 1 January 2004 to 31 December 2008. There were 16 women and 26 men in ages ranging from 43 to 77 years (mean 57.8); 31 epithelioid, 2 sarcomatoid and 9 biphasic type MPM. 21/42 patients were considered possible candidates for multimodality treatment. Three patients who received neoadjuvant chemotherapy were excluded from this study. EBUS/EUS was performed to stage the mediastinal nodes. In 3/18 patients metastatic nodes were discovered. In the rest of the 15 patients simultaneous TEMLA and laparoscopy/peritoneal lavage and cytology of the fluid were performed. In three patients TEMLA was positive, in six patients laparoscopy was positive and in two patients both TEMLA and laparoscopy were positive. Finally, 4/42 (9.5%) patients underwent thoracotomy with one exploration (chest wall infiltration) and three pleuropneumonectomies with the subsequent chemo- and radiotherapy. The proposed algorithm of preoperative staging spared the majority of MPM patients from futile surgery. PMID:19843550

  6. Impedance calculation for ferrite inserts

    SciTech Connect

    Breitzmann, S.C.; Lee, S.Y.; Ng, K.Y.; /Fermilab

    2005-01-01

    Passive ferrite inserts were used to compensate the space charge impedance in high intensity space charge dominated accelerators. They study the narrowband longitudinal impedance of these ferrite inserts. they find that the shunt impedance and the quality factor for ferrite inserts are inversely proportional to the imaginary part of the permeability of ferrite materials. They also provide a recipe for attaining a truly passive space charge impedance compensation and avoiding narrowband microwave instabilities.

  7. Impedance Measurement Box

    ScienceCinema

    Christophersen, Jon

    2013-05-28

    Energy storage devices, primarily batteries, are now more important to consumers, industries and the military. With increasing technical complexity and higher user expectations, there is also a demand for highly accurate state-of-health battery assessment techniques. IMB incorporates patented, proprietary, and tested capabilities using control software and hardware that can be part of an embedded monitoring system. IMB directly measures the wideband impedance spectrum in seconds during battery operation with no significant impact on service life. It also can be applied to batteries prior to installation, confirming health before entering active service, as well as during regular maintenance. For more information about this project, visit http://www.inl.gov/rd100/2011/impedance-measurement-box/

  8. Impedance Measurement Box

    Energy Science and Technology Software Center (ESTSC)

    2014-11-20

    The IMB 50V software provides functionality for design of impedance measurement tests or sequences of tests, execution of these tests or sequences, processing measured responses and displaying and saving of the results. The software consists of a Graphical User Interface that allows configuration of measurement parameters and test sequencing, a core engine that controls test sequencing, execution of measurements, processing and storage of results and a hardware/software data acquisition interface with the IMB hardware system.

  9. Gynecologic electrical impedance tomograph

    NASA Astrophysics Data System (ADS)

    Korjenevsky, A.; Cherepenin, V.; Trokhanova, O.; Tuykin, T.

    2010-04-01

    Electrical impedance tomography extends to the new and new areas of the medical diagnostics: lungs, breast, prostate, etc. The feedback from the doctors who use our breast EIT diagnostic system has induced us to develop the 3D electrical impedance imaging device for diagnostics of the cervix of the uterus - gynecologic impedance tomograph (GIT). The device uses the same measuring approach as the breast imaging system: 2D flat array of the electrodes arranged on the probe with handle is placed against the body. Each of the 32 electrodes of the array is connected in turn to the current source while the rest electrodes acquire the potentials on the surface. The current flows through the electrode of the array and returns through the remote electrode placed on the patient's limb. The voltages are measured relative to another remote electrode. The 3D backprojection along equipotential surfaces is used to reconstruct conductivity distribution up to approximately 1 cm in depth. Small number of electrodes enables us to implement real time imaging with a few frames per sec. rate. The device is under initial testing and evaluation of the imaging capabilities and suitability of usage.

  10. Acoustic ground impedance meter

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J.

    1981-01-01

    A compact, portable instrument was developed to measure the acoustic impedance of the ground, or other surfaces, by direct pressure-volume velocity measurement. A Helmholz resonator, constructed of heavy-walled stainless steel but open at the bottom, is positioned over the surface having the unknown impedance. The sound source, a cam-driven piston of known stroke and thus known volume velocity, is located in the neck of the resonator. The cam speed is a variable up to a maximum 3600 rpm. The sound pressure at the test surface is measured by means of a microphone flush-mounted in the wall of the chamber. An optical monitor of the piston displacement permits measurement of the phase angle between the volume velocity and the sound pressure, from which the real and imaginary parts of the impedance can be evaluated. Measurements using a 5-lobed cam can be made up to 300 Hz. Detailed design criteria and results on a soil sample are presented.

  11. High input impedance amplifier

    NASA Technical Reports Server (NTRS)

    Kleinberg, Leonard L.

    1995-01-01

    High input impedance amplifiers are provided which reduce the input impedance solely to a capacitive reactance, or, in a somewhat more complex design, provide an extremely high essentially infinite, capacitive reactance. In one embodiment, where the input impedance is reduced in essence, to solely a capacitive reactance, an operational amplifier in a follower configuration is driven at its non-inverting input and a resistor with a predetermined magnitude is connected between the inverting and non-inverting inputs. A second embodiment eliminates the capacitance from the input by adding a second stage to the first embodiment. The second stage is a second operational amplifier in a non-inverting gain-stage configuration where the output of the first follower stage drives the non-inverting input of the second stage and the output of the second stage is fed back to the non-inverting input of the first stage through a capacitor of a predetermined magnitude. These amplifiers, while generally useful, are very useful as sensor buffer amplifiers that may eliminate significant sources of error.

  12. [Synovial cyst of chest wall; report of a case].

    PubMed

    Chujo, Masao; Anami, Kentaro; Miura, Takashi

    2014-12-01

    A 55-year-old male taxi driver visited our hospital because of a left dorsal tumor. The tumor was palpated at the inferior angle of the left scapula with tenderness. Computed tomography (CT) revealed a homogeneous 5-cm mass with capsule between the latissimus dorsi muscle and rib. T2-weighted magnetic resonance imaging( MRI) demonstrated the tumor with high intensity. The latissimus dorsi muscle was divided and separated off from the tumor and the lower layer;then, an applied wound retractor (Alexis) was placed under the lower layer of the latissimus dorsi muscle and the operative field was developed. Next, the anterior serratus and greater rhomboid muscles were separated off from the tumor and the lower layer, the Alexis was placed under the lower layer of those muscles. All muscles were preserved and the tumor was removed. The tumor was 56×32 mm in size. The histological diagnosis was synovial cyst. PMID:25434552

  13. Ionospheric effects to antenna impedance

    NASA Technical Reports Server (NTRS)

    Bethke, K. H.

    1986-01-01

    The reciprocity between high power satellite antennas and the surrounding plasma are examined. The relevant plasma states for antenna impedance calculations are presented and plasma models, and hydrodynamic and kinetic theory, are discussed. A theory from which a variation in antenna impedance with regard to the radiated power can be calculated for a frequency range well above the plasma resonance frequency is give. The theory can include photo and secondary emission effects in antenna impedance calculations.

  14. Optically stimulated differential impedance spectroscopy

    DOEpatents

    Maxey, Lonnie C; Parks, II, James E; Lewis, Sr., Samuel A; Partridge, Jr., William P

    2014-02-18

    Methods and apparatuses for evaluating a material are described. Embodiments typically involve use of an impedance measurement sensor to measure the impedance of a sample of the material under at least two different states of illumination. The states of illumination may include (a) substantially no optical stimulation, (b) substantial optical stimulation, (c) optical stimulation at a first wavelength of light, (d) optical stimulation at a second wavelength of light, (e) a first level of light intensity, and (f) a second level of light intensity. Typically a difference in impedance between the impedance of the sample at the two states of illumination is measured to determine a characteristic of the material.

  15. IMPEDANCE OF FINITE LENGTH RESISTOR

    SciTech Connect

    KRINSKY, S.; PODOBEDOV, B.; GLUCKSTERN, R.L.

    2005-05-15

    We determine the impedance of a cylindrical metal tube (resistor) of radius a, length g, and conductivity {sigma}, attached at each end to perfect conductors of semi-infinite length. Our main interest is in the asymptotic behavior of the impedance at high frequency, k >> 1/a. In the equilibrium regime, , the impedance per unit length is accurately described by the well-known result for an infinite length tube with conductivity {sigma}. In the transient regime, ka{sup 2} >> g, we derive analytic expressions for the impedance and wakefield.

  16. Using ac dipoles to localize sources of beam coupling impedance

    NASA Astrophysics Data System (ADS)

    Biancacci, N.; Tomás, R.

    2016-05-01

    The beam coupling impedance is one of the main sources of beam instabilities and emittance blow up in circular accelerators. A refined machine impedance evaluation is therefore required in order to understand and model intensity dependent effects and instabilities that may limit the machine performance. For this reason, many impedance source localization techniques have been developed. In this work we present the impedance localization technique based on the observation of phase advance versus intensity at the beam position monitors using ac dipoles to force betatron oscillations. We present analytical formulas for the interpretation of measurements together with simulations to benchmark and illustrate the equations. Studies on the method accuracy for different Fourier transform algorithms are presented as well as first exploratory measurements performed in the LHC.

  17. Monolithically compatible impedance measurement

    DOEpatents

    Ericson, Milton Nance; Holcomb, David Eugene

    2002-01-01

    A monolithic sensor includes a reference channel and at least one sensing channel. Each sensing channel has an oscillator and a counter driven by the oscillator. The reference channel and the at least one sensing channel being formed integrally with a substrate and intimately nested with one another on the substrate. Thus, the oscillator and the counter have matched component values and temperature coefficients. A frequency determining component of the sensing oscillator is formed integrally with the substrate and has an impedance parameter which varies with an environmental parameter to be measured by the sensor. A gating control is responsive to an output signal generated by the reference channel, for terminating counting in the at least one sensing channel at an output count, whereby the output count is indicative of the environmental parameter, and successive ones of the output counts are indicative of changes in the environmental parameter.

  18. Bioelectrical impedance analysis revisited.

    PubMed

    Mikes, D M; Cha, B A; Dym, C L; Baumgaertner, J; Hartzog, A G; Tacey, A D; Calabria, M R

    1999-12-01

    Although total limb volume measurements are used to track the progress of lymphedema and its treatment, these measurements can be confounded by changes other than fluid excess namely muscle or fat gain. Bioelectrical impedance analysis (BIA) is a technique that specifically quantifies both total body fluid and extracellular fluid in extremities. Whereas BIA has potential as a quick, inexpensive, and quantitative technique to measure directly fluid gain or loss from lymphedema, it also has certain shortcomings that must be addressed before it can be validated. this paper examines the back-ground that explains why measuring total limb volume is insufficient to quantify the extent of peripheral lymphedema and explores the advantages and drawbacks of using BIA for this purpose. PMID:10652699

  19. Robust recursive impedance estimation for automotive lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Fridholm, Björn; Wik, Torsten; Nilsson, Magnus

    2016-02-01

    Recursive algorithms, such as recursive least squares (RLS) or Kalman filters, are commonly used in battery management systems to estimate the electrical impedance of the battery cell. However, these algorithms can in some cases run into problems with bias and even divergence of the estimates. This article illuminates problems that can arise in the online estimation using recursive methods, and lists modifications to handle these issues. An algorithm is also proposed that estimates the impedance by separating the problem in two parts; one estimating the ohmic resistance with an RLS approach, and another one where the dynamic effects are estimated using an adaptive Kalman filter (AKF) that is novel in the battery field. The algorithm produces robust estimates of ohmic resistance and time constant of the battery cell in closed loop with SoC estimation, as demonstrated by both in simulations and with experimental data from a lithium-ion battery cell.

  20. Antenna pattern control using impedance surfaces

    NASA Astrophysics Data System (ADS)

    Balanis, Constantine A.; Liu, Kefeng

    1992-09-01

    During this research period, we have effectively transferred existing computer codes from CRAY supercomputer to work station based systems. The work station based version of our code preserved the accuracy of the numerical computations while giving a much better turn-around time than the CRAY supercomputer. Such a task relieved us of the heavy dependence of the supercomputer account budget and made codes developed in this research project more feasible for applications. The analysis of pyramidal horns with impedance surfaces was our major focus during this research period. Three different modeling algorithms in analyzing lossy impedance surfaces were investigated and compared with measured data. Through this investigation, we discovered that a hybrid Fourier transform technique, which uses the eigen mode in the stepped waveguide section and the Fourier transformed field distributions across the stepped discontinuities for lossy impedances coating, gives a better accuracy in analyzing lossy coatings. After a further refinement of the present technique, we will perform an accurate radiation pattern synthesis in the coming reporting period.

  1. Impedance in School Screening Programs.

    ERIC Educational Resources Information Center

    Robarts, John T.

    1985-01-01

    This paper examines the controversy over use of impedance screening in public schools to identify students with hearing problems, including otitis media, a common ear condition in infants and young children. It cites research that questions the value of pure tone screening as a single test and raises critics' objections to the use of impedance,…

  2. Ultra-wideband impedance sensor

    DOEpatents

    McEwan, Thomas E.

    1999-01-01

    The ultra-wideband impedance sensor (UWBZ sensor, or Z-sensor) is implemented in differential and single-ended configurations. The differential UWBZ sensor employs a sub-nanosecond impulse to determine the balance of an impedance bridge. The bridge is configured as a differential sample-and-hold circuit that has a reference impedance side and an unknown impedance side. The unknown impedance side includes a short transmission line whose impedance is a function of the near proximity of objects. The single-ended UWBZ sensor eliminates the reference side of the bridge and is formed of a sample and hold circuit having a transmission line whose impedance is a function of the near proximity of objects. The sensing range of the transmission line is bounded by the two-way travel time of the impulse, thereby eliminating spurious Doppler modes from large distant objects that would occur in a microwave CW impedance bridge. Thus, the UWBZ sensor is a range-gated proximity sensor. The Z-sensor senses the near proximity of various materials such as metal, plastic, wood, petroleum products, and living tissue. It is much like a capacitance sensor, yet it is impervious to moisture. One broad application area is the general replacement of magnetic sensors, particularly where nonferrous materials need to be sensed. Another broad application area is sensing full/empty levels in tanks, vats and silos, e.g., a full/empty switch in water or petroleum tanks.

  3. Ultra-wideband impedance sensor

    DOEpatents

    McEwan, T.E.

    1999-03-16

    The ultra-wideband impedance sensor (UWBZ sensor, or Z-sensor) is implemented in differential and single-ended configurations. The differential UWBZ sensor employs a sub-nanosecond impulse to determine the balance of an impedance bridge. The bridge is configured as a differential sample-and-hold circuit that has a reference impedance side and an unknown impedance side. The unknown impedance side includes a short transmission line whose impedance is a function of the near proximity of objects. The single-ended UWBZ sensor eliminates the reference side of the bridge and is formed of a sample and hold circuit having a transmission line whose impedance is a function of the near proximity of objects. The sensing range of the transmission line is bounded by the two-way travel time of the impulse, thereby eliminating spurious Doppler modes from large distant objects that would occur in a microwave CW impedance bridge. Thus, the UWBZ sensor is a range-gated proximity sensor. The Z-sensor senses the near proximity of various materials such as metal, plastic, wood, petroleum products, and living tissue. It is much like a capacitance sensor, yet it is impervious to moisture. One broad application area is the general replacement of magnetic sensors, particularly where nonferrous materials need to be sensed. Another broad application area is sensing full/empty levels in tanks, vats and silos, e.g., a full/empty switch in water or petroleum tanks. 2 figs.

  4. Electrochemical Impedance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Retter, Utz; Lohse, Heinz

    Non-steady-state measuring techniques are known to be extremely suitable for the investigation of the electrode kinetics of more complex electrochemical systems. Perturbation of the electrochemical system leads to a shift of the steady state. The rate at which it proceeds to a new steady state depends on characteristic parameters (reaction rate constants, diffusion coefficients, charge transfer resistance, double-layer capacity). Due to non-linearities caused by the electron transfer, low-amplitude perturbation signals are necessary. The small perturbation of the electrode state has the advantage that the solutions of relevant mathematical equations used are transformed in limiting forms that are normally linear. Impedance spectroscopy represents a powerful method for investigation of electrical properties of materials and interfaces of conducting electrodes. Relevant fields of application are the kinetics of charges in bulk or interfacial regions, the charge transfer of ionic or mixed ionic-ionic conductors, semiconducting electrodes, the corrosion inhibition of electrode processes, investigation of coatings on metals, characterisation of materials and solid electrolyte as well as solid-state devices.

  5. I/O impedance controller

    DOEpatents

    Ruesch, Rodney; Jenkins, Philip N.; Ma, Nan

    2004-03-09

    There is disclosed apparatus and apparatus for impedance control to provide for controlling the impedance of a communication circuit using an all-digital impedance control circuit wherein one or more control bits are used to tune the output impedance. In one example embodiment, the impedance control circuit is fabricated using circuit components found in a standard macro library of a computer aided design system. According to another example embodiment, there is provided a control for an output driver on an integrated circuit ("IC") device to provide for forming a resistor divider network with the output driver and a resistor off the IC device so that the divider network produces an output voltage, comparing the output voltage of the divider network with a reference voltage, and adjusting the output impedance of the output driver to attempt to match the output voltage of the divider network and the reference voltage. Also disclosed is over-sampling the divider network voltage, storing the results of the over sampling, repeating the over-sampling and storing, averaging the results of multiple over sampling operations, controlling the impedance with a plurality of bits forming a word, and updating the value of the word by only one least significant bit at a time.

  6. Impedance-estimation methods, modeling methods, articles of manufacture, impedance-modeling devices, and estimated-impedance monitoring systems

    DOEpatents

    Richardson, John G.

    2009-11-17

    An impedance estimation method includes measuring three or more impedances of an object having a periphery using three or more probes coupled to the periphery. The three or more impedance measurements are made at a first frequency. Three or more additional impedance measurements of the object are made using the three or more probes. The three or more additional impedance measurements are made at a second frequency different from the first frequency. An impedance of the object at a point within the periphery is estimated based on the impedance measurements and the additional impedance measurements.

  7. Short-term variability in respiratory impedance and effect of deep breath in asthmatic and healthy subjects with airway smooth muscle activation and unloading.

    PubMed

    Gobbi, Alessandro; Pellegrino, Riccardo; Gulotta, Carlo; Antonelli, Andrea; Pompilio, Pasquale; Crimi, Claudia; Torchio, Roberto; Dutto, Luca; Parola, Paolo; Dellacà, Raffaele L; Brusasco, Vito

    2013-09-01

    Inspiratory resistance (RINSP) and reactance (XINSP) were measured for 7 min at 5 Hz in 10 subjects with mild asymptomatic asthma and 9 healthy subjects to assess the effects of airway smooth muscle (ASM) activation by methacholine (MCh) and unloading by chest wall strapping (CWS) on the variability of lung function and the effects of deep inspiration (DI). Subjects were studied at control conditions, after MCh, with CWS, and after MCh with CWS. In all experimental conditions XINSP was significantly more negative in subjects with asthma than in healthy subjects, suggesting greater inhomogeneity in the former. However, the variability in both RINSP and XINSP was increased by either ASM activation or CWS, without significant difference between groups. DI significantly reversed MCh-induced changes in RINSP both in subjects with asthma and healthy subjects, but XINSP in the former only. This effect was impaired by CWS more in subjects with asthma than in healthy subjects. The velocity of RINSP and XINSP recovery after DI was faster in subjects with asthma than healthy subjects. In conclusion, these results support the opinion that the short-term variability in respiratory impedance is related to ASM tone or operating length, rather than to the disease. Nevertheless, ASM in individuals with asthma differs from that in healthy individuals in an increased velocity of shortening and a reduced sensitivity to mechanical stress when strain is reduced. PMID:23766502

  8. Coupling impedance for modern accelerators

    SciTech Connect

    Heifets, S.A.; Kheifets, S.A. )

    1992-03-10

    A systematic review of theoretical results for the longitudinal and transverse impedances obtained by different methods is presented. The paper comprises definitions, general theorems, modal analysis, a diffraction model, and analytical results. Several new results are included. In particular, necessary and sufficient conditions are given for the independence of the impedance from the beam longitudinal direction. The impedances of two basic simple structures---that of a {ital cavity} and that of a {ital step}---are studied in detail. The transition from the regime of a cavity to the regime of a step is explained, an approximate formula describing this transition is given, and the criterion for determining the applicability of each regime is established. The asymptotic behavior of the impedance for a finite number {ital M} of periodically arranged cavities as a function of {ital M} is studied. The different behaviors of the impedance for a single cavity and that for an infinite number of cavities are explained as resulting from the interference of the diffracted waves. A criterion for determining the transition in the impedance behavior from small {ital M} to large {ital M} is presented.

  9. Arts of electrical impedance tomographic sensing

    PubMed Central

    Wang, Mi; Wang, Qiang; Karki, Bishal

    2016-01-01

    This paper reviews governing theorems in electrical impedance sensing for analysing the relationships of boundary voltages obtained from different sensing strategies. It reports that both the boundary voltage values and the associated sensitivity matrix of an alternative sensing strategy can be derived from a set of full independent measurements and sensitivity matrix obtained from other sensing strategy. A new sensing method for regional imaging with limited measurements is reported. It also proves that the sensitivity coefficient back-projection algorithm does not always work for all sensing strategies, unless the diagonal elements of the transformed matrix, ATA, have significant values and can be approximate to a diagonal matrix. Imaging capabilities of few sensing strategies were verified with static set-ups, which suggest the adjacent electrode pair sensing strategy displays better performance compared with the diametrically opposite protocol, with both the back-projection and multi-step image reconstruction methods. An application of electrical impedance tomography for sensing gas in water two-phase flows is demonstrated. This article is part of the themed issue ‘Supersensing through industrial process tomography’. PMID:27185968

  10. Arts of electrical impedance tomographic sensing.

    PubMed

    Wang, Mi; Wang, Qiang; Karki, Bishal

    2016-06-28

    This paper reviews governing theorems in electrical impedance sensing for analysing the relationships of boundary voltages obtained from different sensing strategies. It reports that both the boundary voltage values and the associated sensitivity matrix of an alternative sensing strategy can be derived from a set of full independent measurements and sensitivity matrix obtained from other sensing strategy. A new sensing method for regional imaging with limited measurements is reported. It also proves that the sensitivity coefficient back-projection algorithm does not always work for all sensing strategies, unless the diagonal elements of the transformed matrix, A(T)A, have significant values and can be approximate to a diagonal matrix. Imaging capabilities of few sensing strategies were verified with static set-ups, which suggest the adjacent electrode pair sensing strategy displays better performance compared with the diametrically opposite protocol, with both the back-projection and multi-step image reconstruction methods. An application of electrical impedance tomography for sensing gas in water two-phase flows is demonstrated. This article is part of the themed issue 'Supersensing through industrial process tomography'. PMID:27185968

  11. Noncontact scanning electrical impedance imaging.

    PubMed

    Liu, Hongze; Hawkins, Aaron; Schultz, Stephen; Oliphant, Travis E

    2004-01-01

    We are interested in applying electrical impedance imaging to a single cell because it has potential to reveal both cell anatomy and cell function. Unfortunately, classic impedance imaging techniques are not applicable to this small scale measurement due to their low resolution. In this paper, a different method of impedance imaging is developed based on a noncontact scanning system. In this system, the imaging sample is immersed in an aqueous solution allowing for the use of various probe designs. Among those designs, we discuss a novel shield-probe design that has the advantage of better signal-to-noise ratio with higher resolution compared to other probes. Images showing the magnitude of current for each scanned point were obtained using this configuration. A low-frequency linear physical model helps to relate the current to the conductivity at each point. Line-scan data of high impedance contrast structures can be shown to be a good fit to this model. The first two-dimensional impedance image of biological tissues generated by this technique is shown with resolution on the order of 100 mum. The image reveals details not present in the optical image. PMID:17271930

  12. [Monitoring cervical dilatation by impedance].

    PubMed

    Salvat, J; Lassen, M; Sauze, C; Baud, S; Salvat, F

    1992-01-01

    Several different physics procedures have been tried to mechanize the recording of partograms. Can a measure of impedance of tissue Z using potential difference V, according to Ohm's law V = Z1, and 1 is a constant, be correlated with a measure of cervical dilatation using vaginal examination? This was our hypothesis. The tissue impedance meter was made to our design and applied according to a bipolar procedure. Our work was carried out on 28 patients. 10 patients were registered before labour started in order to test the apparatus and to record the impedance variations without labour taking place, and 18 patients were registered in labour to see whether there was any correlation. The level of impedance in the cervix without labour was 302.7 Ohms with a deviation of 8.2. Using student's t tests it was found that there was a significant correlation (p less than 0.001) in four measurements between the impedance measure and measures obtained by extrapolating the degrees of dilatation calculated from vaginal examination. This is a preliminary study in which we have defined the conditions that are necessary to confirm these first results and to further develop the method. PMID:1401774

  13. Algorithms and Algorithmic Languages.

    ERIC Educational Resources Information Center

    Veselov, V. M.; Koprov, V. M.

    This paper is intended as an introduction to a number of problems connected with the description of algorithms and algorithmic languages, particularly the syntaxes and semantics of algorithmic languages. The terms "letter, word, alphabet" are defined and described. The concept of the algorithm is defined and the relation between the algorithm and…

  14. Impedances of Laminated Vacuum Chambers

    SciTech Connect

    Burov, A.; Lebedev, V.; /Fermilab

    2011-06-22

    First publications on impedance of laminated vacuum chambers are related to early 70s: those are of S. C. Snowdon [1] and of A. G. Ruggiero [2]; fifteen years later, a revision paper of R. Gluckstern appeared [3]. All the publications were presented as Fermilab preprints, and there is no surprise in that: the Fermilab Booster has its laminated magnets open to the beam. Being in a reasonable mutual agreement, these publications were all devoted to the longitudinal impedance of round vacuum chambers. The transverse impedance and the flat geometry case were addressed in more recent paper of K. Y. Ng [4]. The latest calculations of A. Macridin et al. [5] revealed some disagreement with Ref. [4]; this fact stimulated us to get our own results on that matter. Longitudinal and transverse impendances are derived for round and flat laminated vacuum chambers. Results of this paper agree with Ref. [5].

  15. Evaluation of an electron Monte Carlo dose calculation algorithm for treatment planning.

    PubMed

    Chamberland, Eve; Beaulieu, Luc; Lachance, Bernard

    2015-01-01

    The purpose of this study is to evaluate the accuracy of the electron Monte Carlo (eMC) dose calculation algorithm included in a commercial treatment planning system and compare its performance against an electron pencil beam algorithm. Several tests were performed to explore the system's behavior in simple geometries and in configurations encountered in clinical practice. The first series of tests were executed in a homogeneous water phantom, where experimental measurements and eMC-calculated dose distributions were compared for various combinations of energy and applicator. More specifically, we compared beam profiles and depth-dose curves at different source-to-surface distances (SSDs) and gantry angles, by using dose difference and distance to agreement. Also, we compared output factors, we studied the effects of algorithm input parameters, which are the random number generator seed, as well as the calculation grid size, and we performed a calculation time evaluation. Three different inhomogeneous solid phantoms were built, using high- and low-density materials inserts, to clinically simulate relevant heterogeneity conditions: a small air cylinder within a homogeneous phantom, a lung phantom, and a chest wall phantom. We also used an anthropomorphic phantom to perform comparison of eMC calculations to measurements. Finally, we proceeded with an evaluation of the eMC algorithm on a clinical case of nose cancer. In all mentioned cases, measurements, carried out by means of XV-2 films, radiographic films or EBT2 Gafchromic films. were used to compare eMC calculations with dose distributions obtained from an electron pencil beam algorithm. eMC calculations in the water phantom were accurate. Discrepancies for depth-dose curves and beam profiles were under 2.5% and 2 mm. Dose calculations with eMC for the small air cylinder and the lung phantom agreed within 2% and 4%, respectively. eMC calculations for the chest wall phantom and the anthropomorphic phantom also

  16. Microfabricated Thin Film Impedance Sensor & AC Impedance Measurements

    PubMed Central

    Yu, Jinsong; Liu, Chung-Chiun

    2010-01-01

    Thin film microfabrication technique was employed to fabricate a platinum based parallel-electrode structured impedance sensor. Electrochemical impedance spectroscopy (EIS) and equivalent circuit analysis of the small amplitude (±5 mV) AC impedance measurements (frequency range: 1 MHz to 0.1 Hz) at ambient temperature were carried out. Testing media include 0.001 M, 0.01 M, 0.1 M NaCl and KCl solutions, and alumina (∼3 μm) and sand (∼300 μm) particulate layers saturated with NaCl solutions with the thicknesses ranging from 0.6 mm to 8 mm in a testing cell, and the results were used to assess the effect of the thickness of the particulate layer on the conductivity of the testing solution. The calculated resistances were approximately around 20 MΩ, 4 MΩ, and 0.5 MΩ for 0.001 M, 0.01 M, and 0.1 M NaCl solutions, respectively. The presence of the sand particulates increased the impedance dramatically (6 times and 3 times for 0.001 M and 0.1 M NaCl solutions, respectively). A cell constant methodology was also developed to assess the measurement of the bulk conductivity of the electrolyte solution. The cell constant ranged from 1.2 to 0.8 and it decreased with the increase of the solution thickness. PMID:22219690

  17. Impedance spectra classification for determining the state of charge on a lithium iron phosphate cell using a support vector machine

    NASA Astrophysics Data System (ADS)

    Jansen, P.; Vergossen, D.; Renner, D.; John, W.; Götze, J.

    2015-11-01

    An alternative method for determining the state of charge (SOC) on lithium iron phosphate cells by impedance spectra classification is given. Methods based on the electric equivalent circuit diagram (ECD), such as the Kalman Filter, the extended Kalman Filter and the state space observer, for instance, have reached their limits for this cell chemistry. The new method resigns on the open circuit voltage curve and the parameters for the electric ECD. Impedance spectra classification is implemented by a Support Vector Machine (SVM). The classes for the SVM-algorithm are represented by all the impedance spectra that correspond to the SOC (the SOC classes) for defined temperature and aging states. A divide and conquer based search algorithm on a binary search tree makes it possible to grade measured impedances using the SVM method. Statistical analysis is used to verify the concept by grading every single impedance from each impedance spectrum corresponding to the SOC by class with different magnitudes of charged error.

  18. Intracardiac impedance response during acute AF internal cardioversion using novel rectilinear and capacitor-discharge waveforms.

    PubMed

    Rababah, A S; Walsh, S J; Manoharan, G; Walsh, P R; Escalona, O J

    2016-07-01

    Intracardiac impedance (ICI) is a major determinant of success during internal cardioversion of atrial fibrillation (AF). However, there have been few studies that have examined the dynamic behaviour of atrial impedance during internal cardioversion in relation to clinical outcome. In this study, voltage and current waveforms captured during internal cardioversion of acute AF in ovine models using novel radiofrequency (RF) generated low-tilt rectilinear and conventional capacitor-discharge based shock waveforms were retrospectively analysed using a digital signal processing algorithm to investigate the dynamic behaviour of atrial impedance during cardioversion. The algorithm was specifically designed to facilitate the simultaneous analysis of multiple impedance parameters, including: mean intracardiac impedance (Z M), intracardiac impedance variance (ICIV) and impedance amplitude spectrum area (IAMSA) for each cardioversion event. A significant reduction in ICI was observed when comparing two successive shocks of increasing energy where cardioversion outcome was successful. In addition, ICIV and IAMSA variables were found to inversely correlate to the magnitude of energy delivered; with a stronger correlation found to the former parameter. In conclusion, ICIV and IAMSA have been evidenced as two key dynamic intracardiac impedance variables that may prove useful in better understanding of the cardioversion process and that could potentially act as prognostic markers with respect to clinical outcome. PMID:27328164

  19. Detection of high impedance arcing faults using a multi-layer perceptron

    SciTech Connect

    Sultan, F.F.; Swift, G.W. ); Fedirchuk, D.J. )

    1992-10-01

    A feed-forward three-layer perceptron was trained by high impedance fault, fault-like load, and normal load current patterns, using the back-propagation training algorithm. This paper reports that the neural network parameters were embodied in a high impedance arcing faults detection algorithm, which uses a simple preprocessing technique to prepare the information input to the network. The algorithm was tested by traces of normal load current disturbed by currents of faults on dry and wet soil, an arc welder, computers, and fluorescent lights.

  20. Characteristic impedance of microstrip lines

    NASA Technical Reports Server (NTRS)

    Bailey, M. C.; Deshpande, M. D.

    1989-01-01

    The dyadic Green's function for a current embedded in a grounded dielectric slab is used to analyze microstrip lines at millimeter wave frequencies. The dyadic Green's function accounts accurately for fringing fields and dielectric cover over the microstrip line. Using Rumsey's reaction concept, an expression for the characteristic impedance is obtained. The numerical results are compared with other reported results.

  1. The Aberdeen Impedance Imaging System.

    PubMed

    Kulkarni, V; Hutchison, J M; Mallard, J R

    1989-01-01

    The Aberdeen Impedance Imaging System is designed to reconstruct 2 dimensional images of the average distribution of the amplitude and phase of the complex impedance within a 3 dimensional region. The system uses the four electrode technique in a 16 electrode split-array. The system hardware consists of task-orientated electronic modules for: driving a constant current, multiplexing the current drive, demultiplexing peripheral voltages, differential amplification, phase sensitive detection and low-pass filtration, digitisation with a 14 bit analog to digital converter (ADC), and -control logic for the ADC and multiplexors. A BBC microprocessor (Master series), initiates a controlled sequence for the collection of a number of data sets which are averaged and stored on disk. Image reconstruction is by a process of convolution-backprojection similar to the fan-beam reconstruction of computerised tomography and is also known as Equipotential Backprojection. In imaging impedance changes associated with fracture healing the changes may be large enough to allow retrieval of both the amplitude and phase of the complex impedance. Sequential imaging of these changes would necessitate monitoring electronic and electrode drift by imaging an equivalent region of the contralateral limb. Differential images could be retrieved when the image of the normal limb is the image template. Better characterisation of tissues would necessitate a cleaner retrieval of the quadrature signal. PMID:2742979

  2. Respiratory rate detection algorithm based on RGB-D camera: theoretical background and experimental results.

    PubMed

    Benetazzo, Flavia; Freddi, Alessandro; Monteriù, Andrea; Longhi, Sauro

    2014-09-01

    Both the theoretical background and the experimental results of an algorithm developed to perform human respiratory rate measurements without any physical contact are presented. Based on depth image sensing techniques, the respiratory rate is derived by measuring morphological changes of the chest wall. The algorithm identifies the human chest, computes its distance from the camera and compares this value with the instantaneous distance, discerning if it is due to the respiratory act or due to a limited movement of the person being monitored. To experimentally validate the proposed algorithm, the respiratory rate measurements coming from a spirometer were taken as a benchmark and compared with those estimated by the algorithm. Five tests were performed, with five different persons sat in front of the camera. The first test aimed to choose the suitable sampling frequency. The second test was conducted to compare the performances of the proposed system with respect to the gold standard in ideal conditions of light, orientation and clothing. The third, fourth and fifth tests evaluated the algorithm performances under different operating conditions. The experimental results showed that the system can correctly measure the respiratory rate, and it is a viable alternative to monitor the respiratory activity of a person without using invasive sensors. PMID:26609383

  3. Calibration of electrical impedance tomography

    SciTech Connect

    Daily, W; Ramirez, A

    2000-05-01

    Over the past 10 years we have developed methods for imaging the electrical resistivity of soil and rock formations. These technologies have been called electrical resistance tomography of ERT (e.g. Daily and Owen, 1991). Recently we have been striving to extend this capability to include images of electric impedance--with a new nomenclature of electrical impedance tomography or EIT (Ramirez et al., 1999). Electrical impedance is simply a generalization of resistance. Whereas resistance is the zero frequency ratio of voltage and current, impedance includes both the magnitude and phase relationship between voltage and current at frequency. This phase and its frequency behavior is closely related to what in geophysics is called induced polarization or (Sumner, 1976). Why is this phase or IP important? IP is known to be related to many physical phenomena of importance so that image of IP will be maps of such things as mineralization and cation exchange IP (Marshall and Madden, 1959). Also, it is likely that IP, used in conjunction with resistivity, will yield information about the subsurface that can not be obtained by either piece of information separately. In order to define the accuracy of our technologies to image impedance we have constructed a physical model of known impedance that can be used as a calibration standard. It consists of 616 resistors, along with some capacitors to provide the reactive response, arranged in a three dimensional structure as in figure 1. Figure 2 shows the construction of the network and defines the coordinate system used to describe it. This network of components is a bounded and discrete version of the unbounded and continuous medium with which we normally work (the subsurface). The network has several desirable qualities: (1) The impedance values are known (to the accuracy of the component values). (2) The component values and their 3D distribution is easily controlled. (3) Error associated with electrode noise is eliminated. (4

  4. Journal and Wave Bearing Impedance Calculation Software

    NASA Technical Reports Server (NTRS)

    Hanford, Amanda; Campbell, Robert

    2012-01-01

    The wave bearing software suite is a MALTA application that computes bearing properties for user-specified wave bearing conditions, as well as plain journal bearings. Wave bearings are fluid film journal bearings with multi-lobed wave patterns around the circumference of the bearing surface. In this software suite, the dynamic coefficients are outputted in a way for easy implementation in a finite element model used in rotor dynamics analysis. The software has a graphical user interface (GUI) for inputting bearing geometry parameters, and uses MATLAB s structure interface for ease of interpreting data. This innovation was developed to provide the stiffness and damping components of wave bearing impedances. The computational method for computing bearing coefficients was originally designed for plain journal bearings and tilting pad bearings. Modifications to include a wave bearing profile consisted of changing the film thickness profile given by an equation, and writing an algorithm to locate the integration limits for each fluid region. Careful consideration was needed to implement the correct integration limits while computing the dynamic coefficients, depending on the form of the input/output variables specified in the algorithm.

  5. The quantum Hall impedance standard

    NASA Astrophysics Data System (ADS)

    Schurr, J.; Kučera, J.; Pierz, K.; Kibble, B. P.

    2011-02-01

    Alternating current measurements of double-shielded quantum Hall devices have revealed a fascinating property of which only a quantum effect is capable: it can detect its own frequency dependence and convert it to a current dependence which can be used to eliminate both of them. According to an experimentally verified model, the residual frequency dependence is smaller than the measuring uncertainty of 1.3 × 10-9 kHz-1. In this way, a highly precise quantum standard of impedance can be established, without having to correct for any calculated frequency dependence and without the need for any artefact with a calculated frequency dependence. Nothing else like that is known to us and we hope that our results encourage other national metrology institutes to also apply it to impedance metrology and further explore its beautiful properties.

  6. FXR accelerator cavity impedance experiments

    SciTech Connect

    Avalle, C.A.

    1998-01-05

    One of the goals of the present Flash X-Ray (FXR) accelerator upgrade effort [1][2] at Lawrence Livermore National Laboratory (LLNL) is to reduce the cavity transverse impedance, since it has been shown that beam stability is significantly affected by this parameter [3]. Recently, we have evaluated various techniques and cell modifications to accomplish that, both through lab measurements and computer models. A spare cell, identical in every way to cells in the accelerator, was specially modified for the experiments. The impedance measurements were done without the beam, by applying twin-wire techniques. This report describes the results of these experiments and suggests possible cell modifications to improve their performance. The techniques and modifications which are suggested might also be applicable to AHF and DARHT-2 long-pulse accelerator development.

  7. 21 CFR 870.2770 - Impedance plethysmograph.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Impedance plethysmograph. 870.2770 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2770 Impedance plethysmograph. (a) Identification. An impedance plethysmograph is a device used to estimate peripheral...

  8. 21 CFR 870.2750 - Impedance phlebograph.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Impedance phlebograph. 870.2750 Section 870.2750...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2750 Impedance phlebograph. (a) Identification. An impedance phlebograph is a device used to provide a visual display of...

  9. 21 CFR 870.2770 - Impedance plethysmograph.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Impedance plethysmograph. 870.2770 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2770 Impedance plethysmograph. (a) Identification. An impedance plethysmograph is a device used to estimate peripheral...

  10. 21 CFR 870.2750 - Impedance phlebograph.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Impedance phlebograph. 870.2750 Section 870.2750...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2750 Impedance phlebograph. (a) Identification. An impedance phlebograph is a device used to provide a visual display of...

  11. 21 CFR 870.2750 - Impedance phlebograph.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Impedance phlebograph. 870.2750 Section 870.2750...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2750 Impedance phlebograph. (a) Identification. An impedance phlebograph is a device used to provide a visual display of...

  12. 21 CFR 870.2750 - Impedance phlebograph.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Impedance phlebograph. 870.2750 Section 870.2750...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2750 Impedance phlebograph. (a) Identification. An impedance phlebograph is a device used to provide a visual display of...

  13. 21 CFR 870.2750 - Impedance phlebograph.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Impedance phlebograph. 870.2750 Section 870.2750...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2750 Impedance phlebograph. (a) Identification. An impedance phlebograph is a device used to provide a visual display of...

  14. 21 CFR 870.2770 - Impedance plethysmograph.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Impedance plethysmograph. 870.2770 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2770 Impedance plethysmograph. (a) Identification. An impedance plethysmograph is a device used to estimate peripheral...

  15. 21 CFR 870.2770 - Impedance plethysmograph.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Impedance plethysmograph. 870.2770 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2770 Impedance plethysmograph. (a) Identification. An impedance plethysmograph is a device used to estimate peripheral...

  16. 21 CFR 870.2770 - Impedance plethysmograph.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Impedance plethysmograph. 870.2770 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2770 Impedance plethysmograph. (a) Identification. An impedance plethysmograph is a device used to estimate peripheral...

  17. Impedance analysis of acupuncture points and pathways

    NASA Astrophysics Data System (ADS)

    Teplan, Michal; Kukučka, Marek; Ondrejkovičová, Alena

    2011-12-01

    Investigation of impedance characteristics of acupuncture points from acoustic to radio frequency range is addressed. Discernment and localization of acupuncture points in initial single subject study was unsuccessfully attempted by impedance map technique. Vector impedance analyses determined possible resonant zones in MHz region.

  18. Instrumental noise estimates stabilize and quantify endothelial cell micro-impedance barrier function parameter estimates

    SciTech Connect

    English, Anthony E; Moy, Alan B; Kruse, Kara L; Ward, Richard C; Kirkpatrick, Stacy S; GoldmanM.D., Mitchell H

    2009-04-01

    A novel transcellular micro-impedance biosensor, referred to as the electric cell-substrate impedance sensor or ECIS, has become increasingly applied to the study and quantification of endothelial cell physiology. In principle, frequency dependent impedance measurements obtained from this sensor can be used to estimate the cell cell and cell matrix impedance components of endothelial cell barrier function based on simple geometric models. Few studies, however, have examined the numerical optimization of these barrier function parameters and established their error bounds. This study, therefore, illustrates the implementation of a multi-response Levenberg Marquardt algorithm that includes instrumental noise estimates and applies it to frequency dependent porcine pulmonary artery endothelial cell impedance measurements. The stability of cell cell, cell matrix and membrane impedance parameter estimates based on this approach is carefully examined, and several forms of parameter instability and refinement illustrated. Including frequency dependent noise variance estimates in the numerical optimization reduced the parameter value dependence on the frequency range of measured impedances. The increased stability provided by a multi-response non-linear fit over one-dimensional algorithms indicated that both real and imaginary data should be used in the parameter optimization. Error estimates based on single fits and Monte Carlo simulations showed that the model barrier parameters were often highly correlated with each other. Independently resolving the different parameters can, therefore, present a challenge to the experimentalist and demand the use of non-linear multivariate statistical methods when comparing different sets of parameters.

  19. Combining neural network and genetic algorithm for prediction of lung sounds.

    PubMed

    Güler, Inan; Polat, Hüseyin; Ergün, Uçman

    2005-06-01

    Recognition of lung sounds is an important goal in pulmonary medicine. In this work, we present a study for neural networks-genetic algorithm approach intended to aid in lung sound classification. Lung sound was captured from the chest wall of The subjects with different pulmonary diseases and also from the healthy subjects. Sound intervals with duration of 15-20 s were sampled from subjects. From each interval, full breath cycles were selected. Of each selected breath cycle, a 256-point Fourier Power Spectrum Density (PSD) was calculated. Total of 129 data values calculated by the spectral analysis are selected by genetic algorithm and applied to neural network. Multilayer perceptron (MLP) neural network employing backpropagation training algorithm was used to predict the presence or absence of adventitious sounds (wheeze and crackle). We used genetic algorithms to search for optimal structure and training parameters of neural network for a better predicting of lung sounds. This application resulted in designing of optimum network structure and, hence reducing the processing load and time. PMID:16050077

  20. Transition metal oxide as anode interface buffer for impedance spectroscopy

    NASA Astrophysics Data System (ADS)

    Xu, Hui; Tang, Chao; Wang, Xu-Liang; Zhai, Wen-Juan; Liu, Rui-Lan; Rong, Zhou; Pang, Zong-Qiang; Jiang, Bing; Fan, Qu-Li; Huang, Wei

    2015-12-01

    Impedance spectroscopy is a strong method in electric measurement, which also shows powerful function in research of carrier dynamics in organic semiconductors when suitable mathematical physical models are used. Apart from this, another requirement is that the contact interface between the electrode and materials should at least be quasi-ohmic contact. So in this report, three different transitional metal oxides, V2O5, MoO3 and WO3 were used as hole injection buffer for interface of ITO/NPB. Through the impedance spectroscopy and PSO algorithm, the carrier mobilities and I-V characteristics of the NPB in different devices were measured. Then the data curves were compared with the single layer device without the interface layer in order to investigate the influence of transitional metal oxides on the carrier mobility. The careful research showed that when the work function (WF) of the buffer material was just between the work function of anode and the HOMO of the organic material, such interface material could work as a good bridge for carrier injection. Under such condition, the carrier mobility measured through impedance spectroscopy should be close to the intrinsic value. Considering that the HOMO (or LUMO) of most organic semiconductors did not match with the work function of the electrode, this report also provides a method for wide application of impedance spectroscopy to the research of carrier dynamics.

  1. Electrical impedance tomography with an optimized calculable square sensor.

    PubMed

    Cao, Zhang; Wang, Huaxiang; Xu, Lijun

    2008-10-01

    Electrical impedance tomography is a technique that reconstructs the medium distribution in a region of interest through electrical measurements on its boundary. In this paper, an optimized square sensor was designed for electrical impedance tomography in order to obtain maximum information over the cross section of interest, e.g., circulating fluidized beds, in the sense of Shannon information entropy. An analytical model of the sensor was obtained using the conformal transformation. The model indicates that the square sensor possesses calculable property, which allows the calculation of standard values of the sensor directly from a single dimensional measurement that can be made traceable to the SI unit of length. Based on the model, the sensitivity maps and electrical field lines can be calculated in less than a second. Two model based algorithms for image reconstruction, i.e., back projection algorithm based on electrical field lines and iterative Lavrentiev regularization algorithm based on the sensitivity map, were introduced. Simulated results and experimental results validate the feasibility of the algorithms. PMID:19044722

  2. Constant current loop impedance measuring system that is immune to the effects of parasitic impedances

    NASA Technical Reports Server (NTRS)

    Anderson, Karl F. (Inventor)

    1994-01-01

    A constant current loop measuring system is provided for measuring a characteristic of an environment. The system comprises a first impedance positionable in the environment, a second impedance coupled in series with said first impedance and a parasitic impedance electrically coupled to the first and second impedances. A current generating device, electrically coupled in series with the first and second impedances, provides a constant current through the first and second impedances to produce first and second voltages across the first and second impedances, respectively, and a parasitic voltage across the parasitic impedance. A high impedance voltage measuring device measures a voltage difference between the first and second voltages independent of the parasitic voltage to produce a characteristic voltage representative of the characteristic of the environment.

  3. Joint Impedance Decreases during Movement Initiation

    PubMed Central

    Ludvig, Daniel; Antos, Stephen A.; Perreault, Eric J.

    2013-01-01

    The mechanical properties of the joint influence how we interact with our environment and hence are important in the control of both posture and movement. Many studies have investigated how the mechanical properties—specifically the impedance—of different joints vary with different postural tasks. However, studies on how joint impedance varies with movement remain limited. The few studies that have investigated how impedance varies with movement have found that impedance is lower during movement than during posture. In this study we investigated how impedance changed as people transitioned from a postural task to a movement task. We found that subjects’ joint impedances decreased at the initiation of movement, prior to increasing at the cessation of movement. This decrease in impedance occurred even though the subjects’ torque and EMG levels increased. These findings suggest that during movement the central nervous system may control joint impedance independently of muscle activation. PMID:23366632

  4. Performance of two commercial electron beam algorithms over regions close to the lung-mediastinum interface, against Monte Carlo simulation and point dosimetry in virtual and anthropomorphic phantoms.

    PubMed

    Ojala, J; Hyödynmaa, S; Barańczyk, R; Góra, E; Waligórski, M P R

    2014-03-01

    Electron radiotherapy is applied to treat the chest wall close to the mediastinum. The performance of the GGPB and eMC algorithms implemented in the Varian Eclipse treatment planning system (TPS) was studied in this region for 9 and 16 MeV beams, against Monte Carlo (MC) simulations, point dosimetry in a water phantom and dose distributions calculated in virtual phantoms. For the 16 MeV beam, the accuracy of these algorithms was also compared over the lung-mediastinum interface region of an anthropomorphic phantom, against MC calculations and thermoluminescence dosimetry (TLD). In the phantom with a lung-equivalent slab the results were generally congruent, the eMC results for the 9 MeV beam slightly overestimating the lung dose, and the GGPB results for the 16 MeV beam underestimating the lung dose. Over the lung-mediastinum interface, for 9 and 16 MeV beams, the GGPB code underestimated the lung dose and overestimated the dose in water close to the lung, compared to the congruent eMC and MC results. In the anthropomorphic phantom, results of TLD measurements and MC and eMC calculations agreed, while the GGPB code underestimated the lung dose. Good agreement between TLD measurements and MC calculations attests to the accuracy of "full" MC simulations as a reference for benchmarking TPS codes. Application of the GGPB code in chest wall radiotherapy may result in significant underestimation of the lung dose and overestimation of dose to the mediastinum, affecting plan optimization over volumes close to the lung-mediastinum interface, such as the lung or heart. PMID:23702438

  5. Development of an Anatomically Realistic Forward Solver for Thoracic Electrical Impedance Tomography

    PubMed Central

    Yang, Fei; Zhang, Jie; Patterson, Robert

    2013-01-01

    Electrical impedance tomography (EIT) has the potential to provide a low cost and safe imaging modality for clinically monitoring patients being treated with mechanical ventilation. Variations in reconstruction algorithms at different clinical settings, however, make interpretation of regional ventilation across institutions difficult, presenting the need for a unified algorithm for thoracic EIT reconstruction. Development of such a consensual reconstruction algorithm necessitates a forward model capable of predicting surface impedance measurements as well as electric fields in the interior of the modeled thoracic volume. In this paper, we present an anatomically realistic forward solver for thoracic EIT that was built based on high resolution MR image data of a representative adult. Accuracy assessment of the developed forward solver in predicting surface impedance measurements by comparing the predicted and observed impedance measurements shows that the relative error is within the order of 5%, demonstrating the ability of the presented forward solver in generating high-fidelity surface thoracic impedance data for thoracic EIT algorithm development and evaluation. PMID:27006927

  6. DIFFERENTIAL SOIL IMPEDANCE OBSTACLE DETECTION

    SciTech Connect

    Maximillian J. Kieba

    2002-08-30

    This project develops a new and unique obstacle detection sensor for horizontal directional drilling (HDD) equipment. The development of this new technology will greatly improve the reliability and safety of natural gas HDD construction practices. This sensor utilizes a differential soil impedance measurement technique that will be sensitive to the presence of plastic and ceramic, as well as metallic obstacles. The use of HDD equipment has risen significantly in the gas industry because HDD provides a much more cost-effective and less disruptive method for gas pipe installation than older, trenching methods. However, there have been isolated strikes of underground utilities by HDD equipment, which may have been avoided if methods were available to detect other underground obstacles when using HDD systems. GTI advisors from the gas industry have ranked the value of solving the obstacle detection problem as the most important research and development project for GTI to pursue using Federal Energy Regulatory Commission (FERC) funds available through its industry partner, GRI. GTI proposes to develop a prototype down-hole sensor system that is simple and compact. The sensor utilizes an impedance measurement technique that is sensitive to the presence of metallic or nonmetallic objects in the proximity of the HDD head. The system will use a thin film sensor conformal with the drill head. The impedance of the soil will be measured with a low frequency signal injected through the drill head itself. A pair of bridge type impedance sensors, mounted orthogonal to one another, is capacitively coupled to the soil. Inclusions in the soil will cause changes to the sensor balance distinguishable from homogeneous soil. The sensor will provide range and direction data for obstacles near the HDD head. The goal is to provide a simple, robust system that provides the information required to avoid obstacles. This must be done within the size and ruggedness constraints of the HDD

  7. DIFFERENTIAL SOIL IMPEDANCE OBSTACLE DETECTION

    SciTech Connect

    Maximillian J. Kieba; Christopher J. Ziolkowski

    2004-10-29

    This project develops a new and unique obstacle detection sensor for horizontal directional drilling (HDD) equipment. The development of this new technology will greatly improve the reliability and safety of natural gas HDD construction practices. This sensor utilizes a differential soil impedance measurement technique that will be sensitive to the presence of plastic and ceramic, as well as metallic obstacles. The use of HDD equipment has risen significantly in the gas industry because HDD provides a much more cost-effective and less disruptive method for gas pipe installation than older, trenching methods. However, there have been isolated strikes of underground utilities by HDD equipment, which may have been avoided if methods were available to detect other underground obstacles when using HDD systems. GTI advisors from the gas industry have ranked the value of solving the obstacle detection problem as the most important research and development project for GTI to pursue using Federal Energy Regulatory Commission (FERC) funds available through its industry partner, GRI. GTI proposes to develop a prototype down-hole sensor system that is simple and compact. The sensor utilizes an impedance measurement technique that is sensitive to the presence of metallic or non-metallic objects in the proximity of the HDD head. The system will use a simple sensor incorporated into the drill head. The impedance of the soil will be measured with a low frequency signal injected through the drill head itself. A pair of bridge type impedance sensors, mounted orthogonal to one another, is coupled to the soil. Inclusions in the soil will cause changes to the sensor balance distinguishable from homogeneous soil. The sensor will provide range and direction data for obstacles near the HDD head. The goal is to provide a simple, robust system that provides the information required to avoid obstacles. This must be done within the size and ruggedness constraints of the HDD equipment. Imaging

  8. DIFFERENTIAL SOIL IMPEDANCE OBSTACLE DETECTION

    SciTech Connect

    Maximillian J. Kieba

    2004-05-03

    This project develops a new and unique obstacle detection sensor for horizontal directional drilling (HDD) equipment. The development of this new technology will greatly improve the reliability and safety of natural gas HDD construction practices. This sensor utilizes a differential soil impedance measurement technique that will be sensitive to the presence of plastic and ceramic, as well as metallic obstacles. The use of HDD equipment has risen significantly in the gas industry because HDD provides a much more cost-effective and less disruptive method for gas pipe installation than older, trenching methods. However, there have been isolated strikes of underground utilities by HDD equipment, which may have been avoided if methods were available to detect other underground obstacles when using HDD systems. GTI advisors from the gas industry have ranked the value of solving the obstacle detection problem as the most important research and development project for GTI to pursue using Federal Energy Regulatory Commission (FERC) funds available through its industry partner, GRI. GTI proposes to develop a prototype down-hole sensor system that is simple and compact. The sensor utilizes an impedance measurement technique that is sensitive to the presence of metallic or nonmetallic objects in the proximity of the HDD head. The system will use a simple sensor incorporated into the drill head. The impedance of the soil will be measured with a low frequency signal injected through the drill head itself. A pair of bridge type impedance sensors, mounted orthogonal to one another, is coupled to the soil. Inclusions in the soil will cause changes to the sensor balance distinguishable from homogeneous soil. The sensor will provide range and direction data for obstacles near the HDD head. The goal is to provide a simple, robust system that provides the information required to avoid obstacles. This must be done within the size and ruggedness constraints of the HDD equipment. Imaging

  9. DIFFERENTIAL SOIL IMPEDANCE OBSTACLE DETECTION

    SciTech Connect

    Maximillian J. Kieba

    2004-02-01

    This project develops a new and unique obstacle detection sensor for horizontal directional drilling (HDD) equipment. The development of this new technology will greatly improve the reliability and safety of natural gas HDD construction practices. This sensor utilizes a differential soil impedance measurement technique that will be sensitive to the presence of plastic and ceramic, as well as metallic obstacles. The use of HDD equipment has risen significantly in the gas industry because HDD provides a much more cost-effective and less disruptive method for gas pipe installation than older, trenching methods. However, there have been isolated strikes of underground utilities by HDD equipment, which may have been avoided if methods were available to detect other underground obstacles when using HDD systems. GTI advisors from the gas industry have ranked the value of solving the obstacle detection problem as the most important research and development project for GTI to pursue using Federal Energy Regulatory Commission (FERC) funds available through its industry partner, GRI. GTI proposes to develop a prototype down-hole sensor system that is simple and compact. The sensor utilizes an impedance measurement technique that is sensitive to the presence of metallic or nonmetallic objects in the proximity of the HDD head. The system will use a simple sensor incorporated into the drill head. The impedance of the soil will be measured with a low frequency signal injected through the drill head itself. A pair of bridge type impedance sensors, mounted orthogonal to one another, is coupled to the soil. Inclusions in the soil will cause changes to the sensor balance distinguishable from homogeneous soil. The sensor will provide range and direction data for obstacles near the HDD head. The goal is to provide a simple, robust system that provides the information required to avoid obstacles. This must be done within the size and ruggedness constraints of the HDD equipment. Imaging

  10. DIFFERENTIAL SOIL IMPEDANCE OBSTACLE DETECTION

    SciTech Connect

    Maximillian J. Kieba; Christopher J. Ziolkowski

    2005-01-17

    This project aimed at developing a new and unique obstacle detection sensor for horizontal directional drilling (HDD) equipment. The development of this new technology will greatly improve the reliability and safety of natural gas HDD construction practices. This sensor utilizes a differential soil impedance measurement technique that will be sensitive to the presence of plastic and ceramic, as well as metallic obstacles. The use of HDD equipment has risen significantly in the gas industry because HDD provides a much more cost-effective and less disruptive method for gas pipe installation than older, trenching methods. However, there have been isolated strikes of underground utilities by HDD equipment, which may have been avoided if methods were available to detect other underground obstacles when using HDD systems. GTI advisors from the gas industry ranked the value of solving the obstacle detection problem as the most important research and development project for GTI to pursue using Federal Energy Regulatory Commission (FERC) funds available through its industry partner, GTI. GTI proposed to develop a prototype down-hole sensor system that is simple and compact. The sensor utilizes an impedance measurement technique that is sensitive to the presence of metallic or non-metallic objects in the proximity of the HDD head. The system will use a simple sensor incorporated into the drill head. The impedance of the soil will be measured with a low frequency signal injected through the drill head itself. A pair of bridge type impedance sensors, mounted orthogonal to one another, is coupled to the soil. Inclusions in the soil will cause changes to the sensor balance distinguishable from homogeneous soil. The sensor will provide range and direction data for obstacles near the HDD head. The goal is to provide a simple, robust system that provides the information required to avoid obstacles. This must be done within the size and ruggedness constraints of the HDD equipment

  11. DIFFERENTIAL SOIL IMPEDANCE OBSTACLE DETECTION

    SciTech Connect

    Maximillian J. Kieba

    2003-10-01

    This project develops a new and unique obstacle detection sensor for horizontal directional drilling (HDD) equipment. The development of this new technology will greatly improve the reliability and safety of natural gas HDD construction practices. This sensor utilizes a differential soil impedance measurement technique that will be sensitive to the presence of plastic and ceramic, as well as metallic obstacles. The use of HDD equipment has risen significantly in the gas industry because HDD provides a much more cost-effective and less disruptive method for gas pipe installation than older, trenching methods. However, there have been isolated strikes of underground utilities by HDD equipment, which may have been avoided if methods were available to detect other underground obstacles when using HDD systems. GTI advisors from the gas industry have ranked the value of solving the obstacle detection problem as the most important research and development project for GTI to pursue using Federal Energy Regulatory Commission (FERC) funds available through its industry partner, GRI. GTI proposes to develop a prototype down-hole sensor system that is simple and compact. The sensor utilizes an impedance measurement technique that is sensitive to the presence of metallic or nonmetallic objects in the proximity of the HDD head. The system will use a simple sensor incorporated into the drill head. The impedance of the soil will be measured with a low frequency signal injected through the drill head itself. A pair of bridge type impedance sensors, mounted orthogonal to one another, is coupled to the soil. Inclusions in the soil will cause changes to the sensor balance distinguishable from homogeneous soil. The sensor will provide range and direction data for obstacles near the HDD head. The goal is to provide a simple, robust system that provides the information required to avoid obstacles. This must be done within the size and ruggedness constraints of the HDD equipment. Imaging

  12. Bilateral Impedance Control For Telemanipulators

    NASA Technical Reports Server (NTRS)

    Moore, Christopher L.

    1993-01-01

    Telemanipulator system includes master robot manipulated by human operator, and slave robot performing tasks at remote location. Two robots electronically coupled so slave robot moves in response to commands from master robot. Teleoperation greatly enhanced if forces acting on slave robot fed back to operator, giving operator feeling he or she manipulates remote environment directly. Main advantage of bilateral impedance control: enables arbitrary specification of desired performance characteristics for telemanipulator system. Relationship between force and position modulated at both ends of system to suit requirements of task.

  13. DIFFERENTIAL SOIL IMPEDANCE OBSTACLE DETECTION

    SciTech Connect

    Maximillian J. Kieba; Christopher J. Ziolkowski

    2004-06-30

    This project develops a new and unique obstacle detection sensor for horizontal directional drilling (HDD) equipment. The development of this new technology will greatly improve the reliability and safety of natural gas HDD construction practices. This sensor utilizes a differential soil impedance measurement technique that will be sensitive to the presence of plastic and ceramic, as well as metallic obstacles. The use of HDD equipment has risen significantly in the gas industry because HDD provides a much more cost-effective and less disruptive method for gas pipe installation than older, trenching methods. However, there have been isolated strikes of underground utilities by HDD equipment, which may have been avoided if methods were available to detect other underground obstacles when using HDD systems. GTI advisors from the gas industry have ranked the value of solving the obstacle detection problem as the most important research and development project for GTI to pursue using Federal Energy Regulatory Commission (FERC) funds available through its industry partner, GRI. GTI proposes to develop a prototype down-hole sensor system that is simple and compact. The sensor utilizes an impedance measurement technique that is sensitive to the presence of metallic or nonmetallic objects in the proximity of the HDD head. The system will use a simple sensor incorporated into the drill head. The impedance of the soil will be measured with a low frequency signal injected through the drill head itself. A pair of bridge type impedance sensors, mounted orthogonal to one another, is coupled to the soil. Inclusions in the soil will cause changes to the sensor balance distinguishable from homogeneous soil. The sensor will provide range and direction data for obstacles near the HDD head. The goal is to provide a simple, robust system that provides the information required to avoid obstacles. This must be done within the size and ruggedness constraints of the HDD equipment. Imaging

  14. Impedance spectroscopy of food mycotoxins

    NASA Astrophysics Data System (ADS)

    Bilyy, Oleksandr I.; Yaremyk, Roman Ya.; Kotsyumbas, Ihor Ya.; Kotsyumbas, Halyna I.

    2012-01-01

    A new analytical method of high-selective detection of mycotoxins in food and feed are considered. A method is based on optical registration the changes of conduct of the electric polarized bacterial agents in solution at the action of the external gradient electric fields. Measuring are conducted in integrated electrode-optical cuvette of the special construction, which provides the photometric analysis of forward motion of the objects registration in liquid solution under act of the enclosed electric field and simultaneous registration of kinetics of change of electrical impedance parameters solution and electrode system.

  15. Spheromak Impedance and Current Amplification

    SciTech Connect

    Fowler, T K; Hua, D D; Stallard, B W

    2002-01-31

    It is shown that high current amplification can be achieved only by injecting helicity on the timescale for reconnection, {tau}{sub REC}, which determines the effective impedance of the spheromak. An approximate equation for current amplification is: dI{sub TOR}{sup 2}/dt {approx} I{sup 2}/{tau}{sub REC} - I{sub TOR}{sup 2}/{tau}{sub closed} where I is the gun current, I{sub TOR} is the spheromak toroidal current and {tau}{sub CLOSED} is the ohmic decay time of the spheromak. Achieving high current amplification, I{sub TOR} >> I, requires {tau}{sub REC} <<{tau}{sub CLOSED}. For resistive reconnection, this requires reconnection in a cold zone feeding helicity into a hot zone. Here we propose an impedance model based on these ideas in a form that can be implemented in the Corsica-based helicity transport code. The most important feature of the model is the possibility that {tau}{sub REC} actually increases as the spheromak temperature increases, perhaps accounting for the ''voltage sag'' observed in some experiments, and a tendency toward a constant ratio of field to current, B {proportional_to} I, or I{sub TOR} {approx} I. Program implications are discussed.

  16. Modified sparse regularization for electrical impedance tomography.

    PubMed

    Fan, Wenru; Wang, Huaxiang; Xue, Qian; Cui, Ziqiang; Sun, Benyuan; Wang, Qi

    2016-03-01

    Electrical impedance tomography (EIT) aims to estimate the electrical properties at the interior of an object from current-voltage measurements on its boundary. It has been widely investigated due to its advantages of low cost, non-radiation, non-invasiveness, and high speed. Image reconstruction of EIT is a nonlinear and ill-posed inverse problem. Therefore, regularization techniques like Tikhonov regularization are used to solve the inverse problem. A sparse regularization based on L1 norm exhibits superiority in preserving boundary information at sharp changes or discontinuous areas in the image. However, the limitation of sparse regularization lies in the time consumption for solving the problem. In order to further improve the calculation speed of sparse regularization, a modified method based on separable approximation algorithm is proposed by using adaptive step-size and preconditioning technique. Both simulation and experimental results show the effectiveness of the proposed method in improving the image quality and real-time performance in the presence of different noise intensities and conductivity contrasts. PMID:27036798

  17. Impedance studies on Li-ion cathodes

    SciTech Connect

    NAGASUBRAMANIAN, GANESAN

    2000-04-17

    This paper describes the author's 2- and 3-electrode impedance results of metal oxide cathodes. These results were extracted from impedance data on 18650 Li-ion cells. The impedance results indicate that the ohmic resistance of the cell is very nearly constant with state-of-charge (SOC) and temperature. For example, the ohmic resistance of 18650 Li-ion cells is around 60 m{Omega} for different SOCS (4.1V to 3.0V) and temperatures from 35 C to {minus}20 C. However, the interfacial impedance shows a modest increase with SOC and a huge increase of between 10 and 100 times with decreasing temperature. For example, in the temperature regime (35 C down to {minus}20 C) the overall cell impedance has increased from nearly 200 m{Omega} to 8,000 m{Omega}. Most of the increase in cell impedance comes from the metal oxide cathode/electrolyte interface.

  18. TRANSVERSE IMPEDANCE MEASUREMENT AT THE RHIC.

    SciTech Connect

    ZHANG,S.Y.; HUANG,H.; CAMERON,P.; DREES,A.; FLILLER,R.; SATOGATA,T.

    2002-06-02

    The RHIC transverse impedance was measured during the last operation run. Measurement of the imaginary part of the broadband impedance was the main goal. No large difference between the two rings was found nor in either plane. The measured tune shift is larger than the expected by a factor of 2.5 to 3. Several other issues such as the real part impedance measurement are also presented.

  19. Effects of Liner Length and Attenuation on NASA Langley Impedance Eduction

    NASA Technical Reports Server (NTRS)

    Jones, M. G.; Watson, W. R.

    2016-01-01

    This study explores the effects of liner length and attenuation on the CHE (convected Helmholtz equation) impedance eduction method, in which the surface impedance of an acoustic liner is inferred through an iterative process based on repeated solutions to the convected Helmholtz equation. Wire mesh-over-honeycomb and perforate-over-honeycomb acoustic liners are tested in the NASA Langley Grazing Flow Impedance Tube, and the resultant data are processed using two impedance eduction methods. The first is the CHE method, and the second is a direct method (labeled the KT method) that uses the Kumaresan and Tufts algorithm to compute the impedance directly. The CHE method has been extensively used for acoustic liner evaluation, but experiences anomalous behavior under some test conditions. It is postulated that the anomalies are related to the liner length and/or attenuation. Since the KT method only employs data measured over the length of the liner, it is expected to be unaffected by liner length. A comparison of results achieved with the two impedance eduction methods is used to explore the interactive effects of liner length and attenuation on the CHE impedance eduction method.

  20. Electrical impedance tomography and the fast multipole method

    NASA Astrophysics Data System (ADS)

    Bikowski, Jutta; Mueller, Jennifer L.

    2004-10-01

    A 3-D linearization-based reconstruction algorithm for Electrical Impedance Tomography suitable for breast cancer detection using data collected on a rectangular array was introduced by Mueller et al. [IEEE Biomed. Eng., 46(11), 1999]. By considering the scenario as an electrostatic problem, it is possible to model the electrodes with various charges, facilitating the use of the Fast Multipole Method (FMM) for calculating particle interactions and also supporting the use of different electrode models. In this paper the use of FMM is explained and results in form of reconstructed images from experimental data show that this method is an improvement.

  1. Design and performance evaluation of the NIST digital impedance bridge

    SciTech Connect

    Waltrip, B.C.; Oldham, N.M.

    1994-12-31

    An impedance bridge that compares two-terminal standard inductors to characterized resistors is described. A dual-channel digitally synthesized source and sampling digital multimeter are used to generate and measure relevant bridge signals. A linear interpolation algorithm is used to autocalibrate the bridge to a 1 nF air-dielectric capacitor An intercomparison of the new bridge with existing measurement standards in the low audio frequency range for inductors from 1 mH to 10 H will be reported.

  2. Electrical Impedance Tomography of Electrolysis

    PubMed Central

    Meir, Arie; Rubinsky, Boris

    2015-01-01

    The primary goal of this study is to explore the hypothesis that changes in pH during electrolysis can be detected with Electrical Impedance Tomography (EIT). The study has relevance to real time control of minimally invasive surgery with electrolytic ablation. To investigate the hypothesis, we compare EIT reconstructed images to optical images acquired using pH-sensitive dyes embedded in a physiological saline agar gel phantom treated with electrolysis. We further demonstrate the biological relevance of our work using a bacterial E.Coli model, grown on the phantom. The results demonstrate the ability of EIT to image pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E.coli model. The results are promising, and invite further experimental explorations. PMID:26039686

  3. Impedance Spectroscopy of Human Blood

    NASA Astrophysics Data System (ADS)

    Mesa, Francisco; Bernal, José J.; Sosa, Modesto A.; Villagómez, Julio C.; Palomares, Pascual

    2004-09-01

    The blood is one of the corporal fluids more used with analytical purposes. When the blood is extracted, immediately it is affected by agents that act on it, producing transformations in its elements. Among the effects of these transformations the hemolysis phenomenon stands out, which consists of the membrane rupture and possible death of the red blood cells. The main purpose of this investigation was the quantification of this phenomenon. A Solartron SI-1260 Impedance Spectrometer was used, which covers a frequency range of work from 1 μHz to 10 MHz, and its accuracy has been tested in the accomplishment of several applications. Measurements were performed on 3 mL human blood samples, from healthy donors. Reactive strips for sugar test of 2 μL, from Bayer, were used as electrodes, which allow gathering a portion of the sample, to be analyzed by the spectrometer. Preliminary results of these measurements are presented.

  4. RF discharge impedance measurements using a new method to determine the stray impedances

    SciTech Connect

    Bakker, L.P.; Kroesen, G.M.W.; Hoog, F.J. de )

    1999-06-01

    The impedance of a capacitively coupled radio frequency discharge in a tubular fluorescent lamp filled with neon and mercury is measured. The stray impedances in the electrical network are determined using a new method that requires no extra instruments. The reflection of power is used to determine the stray impedances. Making use of a simple discharge impedance model, the electron density in the lamp is estimated.

  5. Method, system and computer-readable media for measuring impedance of an energy storage device

    DOEpatents

    Morrison, John L.; Morrison, William H.; Christophersen, Jon P.; Motloch, Chester G.

    2016-01-26

    Real-time battery impedance spectrum is acquired using a one-time record. Fast Summation Transformation (FST) is a parallel method of acquiring a real-time battery impedance spectrum using a one-time record that enables battery diagnostics. An excitation current to a battery is a sum of equal amplitude sine waves of frequencies that are octave harmonics spread over a range of interest. A sample frequency is also octave and harmonically related to all frequencies in the sum. A time profile of this sampled signal has a duration that is a few periods of the lowest frequency. A voltage response of the battery, average deleted, is an impedance of the battery in a time domain. Since the excitation frequencies are known and octave and harmonically related, a simple algorithm, FST, processes the time profile by rectifying relative to sine and cosine of each frequency. Another algorithm yields real and imaginary components for each frequency.

  6. PREFACE: XV International Conference on Electrical Bio-Impedance (ICEBI) & XIV Conference on Electrical Impedance Tomography (EIT)

    NASA Astrophysics Data System (ADS)

    Pliquett, Uwe

    2013-04-01

    . Structures down to sub-micrometer range and complex impedance measurements tools integrated at single chips are now affordable. Moreover, the introduction of alternative signals and data processing algorithms focuses on very fast and parallel electrical characterization which in turn pushes this technique to new applications and markets. Electrical impedance tomography today yields pictures in real time with a resolution that was impossible 10 years ago. The XVth International Conference on Electrical Bio-Impedance in conjunction with the XIVth Electrical Impedance Tomography ICEBI/EIT 2013 organized by the Institute for Bioprocessing and Analytical Measurement Techniques, Heilbad Heiligenstadt, Germany, together with the EIT-group at the University of Göttingen, Germany, brings world leading scientists in these fields together. It is a platform to present the latest developments in instrumentation and signal processing but also points to new applications, especially in the field of biosensors and non-linear phenomena. Two Keynote lectures will extend the view of the participants above the mainstream of bio-impedance measurement. Friederich Kremer (University of Leipzig) delivers the plenary lecture on broad bandwidth dielectric spectroscopy. New achievements in the research of ligand gated ionic channels will be presented by Klaus Benndorf (University of Jena). Leading scientists in the field of bio-impedance measurement, such as, Sverre Grimnes, Orjan Martinsen, Andrea Robitzki, Richard Bayford, Jan Gimsa and Mart Min will give lectures for students but also more experienced scientists in a pre-conference tutorial which is a good opportunity to learn or refresh the basics. List of committees Conference Chair Dr Uwe Pliquett Professor Dieter Beckmann Institut für Bioprozess- und Analysenmesstechnik eV, Rosenhof, Heilbad Heiligenstadt, Germany Technical Program Chair Maik Hiller Conventus Congressmanagement & Marketing GmbH, Carl-Pulfrich-Str. 1 - 07745 Jena Pre

  7. PREFACE: XV International Conference on Electrical Bio-Impedance (ICEBI) & XIV Conference on Electrical Impedance Tomography (EIT)

    NASA Astrophysics Data System (ADS)

    Pliquett, Uwe

    2013-04-01

    . Structures down to sub-micrometer range and complex impedance measurements tools integrated at single chips are now affordable. Moreover, the introduction of alternative signals and data processing algorithms focuses on very fast and parallel electrical characterization which in turn pushes this technique to new applications and markets. Electrical impedance tomography today yields pictures in real time with a resolution that was impossible 10 years ago. The XVth International Conference on Electrical Bio-Impedance in conjunction with the XIVth Electrical Impedance Tomography ICEBI/EIT 2013 organized by the Institute for Bioprocessing and Analytical Measurement Techniques, Heilbad Heiligenstadt, Germany, together with the EIT-group at the University of Göttingen, Germany, brings world leading scientists in these fields together. It is a platform to present the latest developments in instrumentation and signal processing but also points to new applications, especially in the field of biosensors and non-linear phenomena. Two Keynote lectures will extend the view of the participants above the mainstream of bio-impedance measurement. Friederich Kremer (University of Leipzig) delivers the plenary lecture on broad bandwidth dielectric spectroscopy. New achievements in the research of ligand gated ionic channels will be presented by Klaus Benndorf (University of Jena). Leading scientists in the field of bio-impedance measurement, such as, Sverre Grimnes, Orjan Martinsen, Andrea Robitzki, Richard Bayford, Jan Gimsa and Mart Min will give lectures for students but also more experienced scientists in a pre-conference tutorial which is a good opportunity to learn or refresh the basics. List of committees Conference Chair Dr Uwe Pliquett Professor Dieter Beckmann Institut für Bioprozess- und Analysenmesstechnik eV, Rosenhof, Heilbad Heiligenstadt, Germany Technical Program Chair Maik Hiller Conventus Congressmanagement & Marketing GmbH, Carl-Pulfrich-Str. 1 - 07745 Jena Pre

  8. Far-infrared embedding impedance measurements

    NASA Technical Reports Server (NTRS)

    Neikirk, D. P.; Rutledge, D. B.

    1984-01-01

    A technique which allows the measurement of detector embedding impedance has been developed. By using a bismuth microbolometer as a variable resistance load the impedance of one element in a bow-tie antenna array operating at 94 GHz was inferred. The technique is frequency insensitive, and could be used throughout the far-infrared.

  9. How good is the impedance boundary condition?

    NASA Technical Reports Server (NTRS)

    Lee, Shung-Wu; Gee, W.

    1987-01-01

    The impedance boundary condition (IBC) is often used in scattering problems involving material-coated conducting bodies. It is shown that for some commonly encountered coating configurations, the value of the impedance varies significantly as functions of the incident angle and polarization. Hence, the use of IBC in a rigorously formulated problem may affect the accuracy of the final solution.

  10. FDTD modeling of thin impedance sheets

    NASA Technical Reports Server (NTRS)

    Luebbers, Raymond J.; Kunz, Karl S.

    1991-01-01

    Thin sheets of resistive or dielectric material are commonly encountered in radar cross section calculations. Analysis of such sheets is simplified by using sheet impedances. In this paper it is shown that sheet impedances can be modeled easily and accurately using Finite Difference Time Domain (FDTD) methods.

  11. Esophageal Impedance Monitoring: Clinical Pearls and Pitfalls.

    PubMed

    Ravi, Karthik; Katzka, David A

    2016-09-01

    The development of intraluminal esophageal impedance monitoring has improved our ability to detect and measure gastroesophageal reflux without dependence on acid content. This ability to detect previously unrecognized weak or nonacid reflux episodes has had important clinical implications in the diagnosis and management of gastroesophageal reflux disease (GERD). In addition, with the ability to assess bolus transit within the esophageal lumen, impedance monitoring has enhanced the recognition and characterization of esophageal motility disorders in patients with nonobstructive dysphagia. The assessment of the intraluminal movement of gas and liquid has also been proven to be of diagnostic value in conditions such as rumination syndrome and excessive belching. Further, alternative applications of impedance monitoring, such as the measurement of mucosal impedance, have provided novel insights into assessing esophageal mucosal integrity changes as a consequence of inflammatory change. Future applications for esophageal impedance monitoring also hold promise in esophageal conditions other than GERD. However, despite all of the clinical benefits afforded by esophageal impedance monitoring, important clinical and technical shortcomings limit its diagnostic value and must be considered when interpreting study results. Overinterpretation of studies or application of impedance monitoring in patients can have deleterious clinical implications. This review will highlight the clinical benefits and limitations of esophageal impedance monitoring and provide clinical pearls and pitfalls associated with this technology. PMID:27325223

  12. Possibilities of electrical impedance tomography in gynecology

    NASA Astrophysics Data System (ADS)

    V, Trokhanova O.; A, Chijova Y.; B, Okhapkin M.; V, Korjenevsky A.; S, Tuykin T.

    2013-04-01

    The paper describes results of comprehensive EIT diagnostics of mammary glands and cervix. The data were obtained from examinations of 170 patients by EIT system MEM (multi-frequency electrical impedance mammograph) and EIT system GIT (gynecological impedance tomograph). Mutual dependence is discussed.

  13. Active impedance matching of complex structural systems

    NASA Technical Reports Server (NTRS)

    Macmartin, Douglas G.; Miller, David W.; Hall, Steven R.

    1991-01-01

    Viewgraphs on active impedance matching of complex structural systems are presented. Topics covered include: traveling wave model; dereverberated mobility model; computation of dereverberated mobility; control problem: optimal impedance matching; H2 optimal solution; statistical energy analysis (SEA) solution; experimental transfer functions; interferometer actuator and sensor locations; active strut configurations; power dual variables; dereverberation of complex structure; dereverberated transfer function; compensators; and relative power flow.

  14. Impedance of finite length resistive cylinder

    NASA Astrophysics Data System (ADS)

    Krinsky, S.; Podobedov, B.; Gluckstern, R. L.

    2004-11-01

    We determine the impedance of a cylindrical metal tube (resistor) of radius a, length g, and conductivity σ attached at each end to perfect conductors of semi-infinite length. Our main interest is in the asymptotic behavior of the impedance at high frequency (k≫1/a). In the equilibrium regime, ka2≪g, the impedance per unit length is accurately described by the well-known result for an infinite length tube with conductivity σ. In the transient regime, ka2≫g, where the contribution of transition radiation arising from the discontinuity in conductivity is important, we derive an analytic expression for the impedance and compute the short-range wakefield. The analytic results are shown to agree with numerical evaluation of the impedance.

  15. REVIEW ARTICLE: EIT reconstruction algorithms: pitfalls, challenges and recent developments

    NASA Astrophysics Data System (ADS)

    Lionheart, William R. B.

    2004-02-01

    We review developments, issues and challenges in electrical impedance tomography (EIT) for the 4th Conference on Biomedical Applications of Electrical Impedance Tomography, held at Manchester in 2003. We focus on the necessity for three-dimensional data collection and reconstruction, efficient solution of the forward problem, and both present and future reconstruction algorithms. We also suggest common pitfalls or 'inverse crimes' to avoid.

  16. Tracking of electrochemical impedance of batteries

    NASA Astrophysics Data System (ADS)

    Piret, H.; Granjon, P.; Guillet, N.; Cattin, V.

    2016-04-01

    This paper presents an evolutionary battery impedance estimation method, which can be easily embedded in vehicles or nomad devices. The proposed method not only allows an accurate frequency impedance estimation, but also a tracking of its temporal evolution contrary to classical electrochemical impedance spectroscopy methods. Taking into account constraints of cost and complexity, we propose to use the existing electronics of current control to perform a frequency evolutionary estimation of the electrochemical impedance. The developed method uses a simple wideband input signal, and relies on a recursive local average of Fourier transforms. The averaging is controlled by a single parameter, managing a trade-off between tracking and estimation performance. This normalized parameter allows to correctly adapt the behavior of the proposed estimator to the variations of the impedance. The advantage of the proposed method is twofold: the method is easy to embed into a simple electronic circuit, and the battery impedance estimator is evolutionary. The ability of the method to monitor the impedance over time is demonstrated on a simulator, and on a real Lithium ion battery, on which a repeatability study is carried out. The experiments reveal good tracking results, and estimation performance as accurate as the usual laboratory approaches.

  17. Estimates of Acausal Joint Impedance Models

    PubMed Central

    Perreault, Eric J.

    2013-01-01

    Estimates of joint or limb impedance are commonly used in the study of how the nervous system controls posture and movement, and how that control is altered by injury to the neural or musculoskeletal systems. Impedance characterizes the dynamic relationship between an imposed perturbation of joint position and the torques generated in response. While there are many practical reasons for estimating impedance rather than its inverse, admittance, it is an acausal representation of the limb mechanics that can lead to difficulties in interpretation or use. The purpose of this study was to explore the acausal nature of nonparametric estimates of joint impedance representations to determine how they are influenced by common experimental and computational choices. This was accomplished by deriving discrete-time realizations of first-and second-order derivatives to illustrate two key difficulties in the physical interpretation of impedance impulse response functions. These illustrations were provided using both simulated and experimental data. It was found that the shape of the impedance impulse response depends critically on the selected sampling rate, and on the bandwidth and noise characteristics of the position perturbation used during the estimation process. These results provide important guidelines for designing experiments in which nonparametric estimates of impedance will be obtained, especially when those estimates are to be used in a multistep identification process. PMID:22907963

  18. Estimates of acausal joint impedance models.

    PubMed

    Westwick, David T; Perreault, Eric J

    2012-10-01

    Estimates of joint or limb impedance are commonly used in the study of how the nervous system controls posture and movement, and how that control is altered by injury to the neural or musculoskeletal systems. Impedance characterizes the dynamic relationship between an imposed perturbation of joint position and the torques generated in response. While there are many practical reasons for estimating impedance rather than its inverse, admittance, it is an acausal representation of the limb mechanics that can lead to difficulties in interpretation or use. The purpose of this study was to explore the acausal nature of nonparametric estimates of joint impedance representations to determine how they are influenced by common experimental and computational choices. This was accomplished by deriving discrete-time realizations of first- and second-order derivatives to illustrate two key difficulties in the physical interpretation of impedance impulse response functions. These illustrations were provided using both simulated and experimental data. It was found that the shape of the impedance impulse response depends critically on the selected sampling rate, and on the bandwidth and noise characteristics of the position perturbation used during the estimation process. These results provide important guidelines for designing experiments in which nonparametric estimates of impedance will be obtained, especially when those estimates are to be used in a multistep identification process. PMID:22907963

  19. Measurements of electrical impedance of biomedical objects.

    PubMed

    Frączek, Marcin; Kręcicki, Tomasz; Moron, Zbigniew; Krzywaźnia, Adam; Ociepka, Janusz; Rucki, Zbigniew; Szczepanik, Zdzisław

    2016-01-01

    Some basic problems related to measurements of electrical impedance of biological objects (bioimpedance) have been presented in this paper. Particularly problems arising from impedance occurring at the sensor-tissue interface (interfacial impedances) in contact measuring methods have been discussed. The influence of finite values of impedances of the current source and voltage measuring device has also been taken into consideration. A model of the impedance sensor for the four-electrode measurement method containing the interfacial, source and measuring device impedances has been given and its frequency characteristics obtained by the computer simulation have been presented. The influence of these impedances on the shape of frequency characteristic of the sensor model has been discussed. Measurements of bioimpedance of healthy and anomalous soft tissues have been described. Some experimental results, particularly the frequency characteristics of bioimpedance, have been shown. The presented results of measurement show that bioimpedance can be a valuable source of information about the tissues, so measurement of bioimpedance can be a useful supplement to other medical diagnostic methods. PMID:27151250

  20. Summary of the impedance working group

    SciTech Connect

    Chao, A.W.

    1995-05-01

    The impedance working group concentrated on the LHC design during the workshop. They look at the impedance contributions of liner, beam position monitors, shielded bellows, experimental chambers, superconducting cavities, recombination chambers, space charge, kickers, and the resistive wall. The group concluded that the impedance budgeting and the conceptual designs of the vacuum chamber components looked basically sound. It also noted, not surprisingly, that a large amount of studies are to be carried out further, and it ventured to give a partial list of these studies.

  1. FDTD modeling of thin impedance sheets

    NASA Technical Reports Server (NTRS)

    Luebbers, Raymond; Kunz, Karl

    1991-01-01

    Thin sheets of resistive or dielectric material are commonly encountered in radar cross section calculations. Analysis of such sheets is simplified by using sheet impedances. It is shown that sheet impedances can be modeled easily and accurately using Finite Difference Time Domain (FDTD) methods. These sheets are characterized by a discontinuity in the tangential magnetic field on either side of the sheet but no discontinuity in tangential electric field. This continuity, or single valued behavior of the electric field, allows the sheet current to be expressed in terms of an impedance multiplying this electric field.

  2. Koch fractal boundary patch over reactive impedance

    NASA Astrophysics Data System (ADS)

    Reddy V, Venkateshwar; Sarma, N. V. S. N.

    2013-04-01

    This paper describes the enhancement of bandwidth and miniaturization for patch antennas. Introduction of fractal structure (Square Koch) over reactive impedance surface (RIS) is used to enhance impedance bandwidth while minimizing the patch size. Comparison has been made with those of a single-layer (sub1) antenna and the corresponding dual-layer (RIS) antenna. Approximately double the impedance bandwidth is achieved with the proposed RIS Square Koch antenna 1 when compared with Square Koch antenna 1without RIS. There is a 55 % reduction in the patch size. The simulated results indicate that the presented antennas provide gain of about 2.5dBi over the entire band of frequencies.

  3. RHIC ABORT KICKER WITH REDUCED COUPLING IMPEDANCE.

    SciTech Connect

    HAHN,H.; DAVINO,D.

    2002-06-02

    Kicker magnets typically represent the most important contributors to the transverse impedance budget of accelerators and storage rings. Methods of reducing the impedance value of the SNS extraction kicker presently under construction and, in view of a future performance upgrade, that of the RHIC abort kicker have been thoroughly studied at this laboratory. In this paper, the investigation of a potential improvement from using ferrite different from the BNL standard CMD5005 is reported. Permeability measurements of several ferrite types have been performed. Measurements on two kicker magnets using CMD5005 and C2050 suggest that the impedance of a magnet without external resistive damping, such as the RHIC abort kicker, would benefit.

  4. A dynamic oppositional biogeography-based optimization approach for time-varying electrical impedance tomography.

    PubMed

    Rashid, A; Kim, S; Liu, D; Kim, K Y

    2016-06-01

    Dynamic electrical impedance tomography-based image reconstruction using conventional algorithms such as the extended Kalman filter often exhibits inferior performance due to the presence of measurement noise, the inherent ill-posed nature of the problem and its critical dependence on the selection of the initial guess as well as the state evolution model. Moreover, many of these conventional algorithms require the calculation of a Jacobian matrix. This paper proposes a dynamic oppositional biogeography-based optimization (OBBO) technique to estimate the shape, size and location of the non-stationary region boundaries, expressed as coefficients of truncated Fourier series, inside an object domain using electrical impedance tomography. The conductivity of the object domain is assumed to be known a priori. Dynamic OBBO is a novel addition to the family of dynamic evolutionary algorithms. Moreover, it is the first such study on the application of dynamic evolutionary algorithms for dynamic electrical impedance tomography-based image reconstruction. The performance of the algorithm is tested through numerical simulations and experimental study and is compared with state-of-the-art gradient-based extended Kalman filter. The dynamic OBBO is shown to be far superior compared to the extended Kalman filter. It is found to be robust to measurement noise as well as the initial guess, and does not rely on a priori knowledge of the state evolution model. PMID:27203482

  5. In vivo impedance imaging with total variation regularization.

    PubMed

    Borsic, Andrea; Graham, Brad M; Adler, Andy; Lionheart, William R B

    2010-01-01

    We show that electrical impedance tomography (EIT) image reconstruction algorithms with regularization based on the total variation (TV) functional are suitable for in vivo imaging of physiological data. This reconstruction approach helps to preserve discontinuities in reconstructed profiles, such as step changes in electrical properties at interorgan boundaries, which are typically smoothed by traditional reconstruction algorithms. The use of the TV functional for regularization leads to the minimization of a nondifferentiable objective function in the inverse formulation. This cannot be efficiently solved with traditional optimization techniques such as the Newton method. We explore two implementations methods for regularization with the TV functional: the lagged diffusivity method and the primal dual-interior point method (PD-IPM). First we clarify the implementation details of these algorithms for EIT reconstruction. Next, we analyze the performance of these algorithms on noisy simulated data. Finally, we show reconstructed EIT images of in vivo data for ventilation and gastric emptying studies. In comparison to traditional quadratic regularization, TV regularization shows improved ability to reconstruct sharp contrasts. PMID:20051330

  6. Mutual impedance computation between printed dipoles

    NASA Astrophysics Data System (ADS)

    Alexopoulos, N. G.; Rana, I. E.

    1981-01-01

    The mutual impedance between microstrip dipoles printed on a grounded substrate is computed. Results for the microstrip dipoles in broadside, collinear, and echelon arrangements are presented. The significance of surface wave to mutual coupling is discussed.

  7. Antenna pattern control using impedance surfaces

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Liu, Kefeng; Tirkas, Panayiotis A.

    1993-01-01

    During the period of this research project, a comprehensive study of pyramidal horn antennas was conducted. Full-wave analytical and numerical techniques were developed to analyze horn antennas with or without impedance surfaces. Based on these full-wave analytic techniques, research was conducted on the use of impedance surfaces on the walls of the horn antennas to control the antenna radiation patterns without a substantial loss of antenna gain. It was found that the use of impedance surfaces could modify the antenna radiation patterns. In addition to the analytical and numerical models, experimental models were also constructed and they were used to validate the predictions. Excellent agreement between theoretical predictions and the measured data was obtained for pyramidal horns with perfectly conducting surfaces. Very good comparisons between numerical and experimental models were also obtained for horns with impedance surfaces.

  8. Acoustic input impedance measurements on brass instruments

    NASA Astrophysics Data System (ADS)

    Pyle, Robert W., Jr.

    2002-11-01

    Measurement of the acoustic input impedance of a brass instrument can reveal something about the instrument's intonation, its reasonable playing range, its tone color, and perhaps whether the mouthpiece used for the impedance measurement is appropriate for the instrument. Such measurements are made at sound-presssure levels much lower than those encountered under playing conditions. Thus, impedance measurements may offer the only feasible way to infer something about the playing characteristics of instruments, typically museum specimens, that are too rare or too fragile to be played. In this paper the effects of some of the available choices of sound source and stimulus signal on measurement accuracy will be explored. Driver-transducer nonlinearity, source impedance, signal-to-noise ratio, and any necessary signal processing will be discussed.

  9. Impedance feedback control for scanning electrochemical microscopy.

    PubMed

    Alpuche-Aviles, M A; Wipf, D O

    2001-10-15

    A new constant-distance imaging method based on the relationship between tip impedance and tip-substrate separation has been developed for the scanning electrochemical microscope. The tip impedance is monitored by application of a high-frequency ac voltage bias between the tip and auxiliary electrode. The high-frequency ac current is easily separated from the dc-level faradaic electrochemistry with a simple RC filter, which allows impedance measurements during feedback or generation/collection experiments. By employing a piezo-based feedback controller, we are able to maintain the impedance at a constant value and, thus, maintain a constant tip-substrate separation. Application of the method to feedback and generation/collection experiments with tip electrodes as small as 2 microm is presented. PMID:11681463

  10. Inversion of elastic impedance for unconsolidated sediments

    USGS Publications Warehouse

    Lee, Myung W.

    2006-01-01

    Elastic properties of gas-hydrate-bearing sediments are important for quantifying gas hydrate amounts as well as discriminating the gas hydrate effect on velocity from free gas or pore pressure. This paper presents an elastic inversion method for estimating elastic properties of gas-hydrate-bearing sediments from angle stacks using sequential inversion of P-wave impedance from the zero-offset stack and S-wave impedance from the far-offset stack without assuming velocity ratio.

  11. CSR Impedance for Non-Ultrarelativistic Beams

    SciTech Connect

    Li, Rui; Tsai, Cheng Y.

    2015-09-01

    For the analysis of the coherent synchrotron radiation (CSR)-induced microbunching gain in the low energy regime, such as when a high-brightness electron beam is transported through a low-energy merger in an energy-recovery linac (ERL) design, it is necessary to extend the CSR impedance expression in the ultrarelativistic limit to the non-ultrarelativistic regime. This paper presents our analysis of CSR impedance for general beam energies.

  12. Wave impedance of an atomically thin crystal.

    PubMed

    Merano, Michele

    2015-11-30

    I propose an expression for the electromagnetic wave impedance of a two-dimensional atomic crystal, and I deduce the Fresnel coefficients in terms of this quantity. It is widely known that a two-dimensional crystal can absorb light, if its conductivity is different from zero. It is less emphasized that they can also store a certain amount of electromagnetic energy. The concept of impedance is useful to quantify this point. PMID:26698783

  13. Acoustic impedance microscopy for biological tissue characterization.

    PubMed

    Kobayashi, Kazuto; Yoshida, Sachiko; Saijo, Yoshifumi; Hozumi, Naohiro

    2014-09-01

    A new method for two-dimensional acoustic impedance imaging for biological tissue characterization with micro-scale resolution was proposed. A biological tissue was placed on a plastic substrate with a thickness of 0.5mm. A focused acoustic pulse with a wide frequency band was irradiated from the "rear side" of the substrate. In order to generate the acoustic wave, an electric pulse with two nanoseconds in width was applied to a PVDF-TrFE type transducer. The component of echo intensity at an appropriate frequency was extracted from the signal received at the same transducer, by performing a time-frequency domain analysis. The spectrum intensity was interpreted into local acoustic impedance of the target tissue. The acoustic impedance of the substrate was carefully assessed prior to the measurement, since it strongly affects the echo intensity. In addition, a calibration was performed using a reference material of which acoustic impedance was known. The reference material was attached on the same substrate at different position in the field of view. An acoustic impedance microscopy with 200×200 pixels, its typical field of view being 2×2 mm, was obtained by scanning the transducer. The development of parallel fiber in cerebella cultures was clearly observed as the contrast in acoustic impedance, without staining the specimen. The technique is believed to be a powerful tool for biological tissue characterization, as no staining nor slicing is required. PMID:24852259

  14. Modeling magnetically insulated devices using flow impedance

    SciTech Connect

    Mendel, C.W. Jr.; Rosenthal, S.E. )

    1995-04-01

    In modern pulsed power systems the electric field stresses at metal surfaces in vacuum transmission lines are so high that negative surfaces are space-charge-limited electron emitters. These electrons do not cause unacceptable losses because magnetic fields due to system currents result in net motion parallel to the electrodes. It has been known for several years that a parameter known as flow impedance is useful for describing these flows. Flow impedance is a measure of the separation between the anode and the mean position of the electron cloud, and it will be shown in this paper that in many situations flow impedance depends upon the geometry of the transmission line upstream of the point of interest. It can be remarkably independent of other considerations such as line currents and voltage. For this reason flow impedance is a valuable design parameter. Models of impedance transitions and voltage adders using flow impedance will be developed. Results of these models will be compared to two-dimensional, time-dependent, particle-in-cell simulations.

  15. Experimental study of coupling impedance: Part I longitudinal impedance measurement techniques

    SciTech Connect

    Song, J.J.

    1991-10-22

    Beam coupling impedances for the 7-GeV APS storage ring have been numerically estimated. In order to confirm these calculations, measurements of the coupling impedance of various vacuum components around the main storage ring were done with a coaxial wire method. In this paper, the procedure of the longitudinal impedance measurement techniques will be described. As an example, sections of the Cu beam chamber, the Cu beam + antechambers, and the Al beam + antechambers were used as a device under test (DUT) to obtain the results. The transverse impedance measurements will be described in a separate paper.

  16. Comprehensive evaluation and clinical implementation of commercially available Monte Carlo dose calculation algorithm.

    PubMed

    Zhang, Aizhen; Wen, Ning; Nurushev, Teamour; Burmeister, Jay; Chetty, Indrin J

    2013-01-01

    A commercial electron Monte Carlo (eMC) dose calculation algorithm has become available in Eclipse treatment planning system. The purpose of this work was to evaluate the eMC algorithm and investigate the clinical implementation of this system. The beam modeling of the eMC algorithm was performed for beam energies of 6, 9, 12, 16, and 20 MeV for a Varian Trilogy and all available applicator sizes in the Eclipse treatment planning system. The accuracy of the eMC algorithm was evaluated in a homogeneous water phantom, solid water phantoms containing lung and bone materials, and an anthropomorphic phantom. In addition, dose calculation accuracy was compared between pencil beam (PB) and eMC algorithms in the same treatment planning system for heterogeneous phantoms. The overall agreement between eMC calculations and measurements was within 3%/2 mm, while the PB algorithm had large errors (up to 25%) in predicting dose distributions in the presence of inhomogeneities such as bone and lung. The clinical implementation of the eMC algorithm was investigated by performing treatment planning for 15 patients with lesions in the head and neck, breast, chest wall, and sternum. The dose distributions were calculated using PB and eMC algorithms with no smoothing and all three levels of 3D Gaussian smoothing for comparison. Based on a routine electron beam therapy prescription method, the number of eMC calculated monitor units (MUs) was found to increase with increased 3D Gaussian smoothing levels. 3D Gaussian smoothing greatly improved the visual usability of dose distributions and produced better target coverage. Differences of calculated MUs and dose distributions between eMC and PB algorithms could be significant when oblique beam incidence, surface irregularities, and heterogeneous tissues were present in the treatment plans. In our patient cases, monitor unit differences of up to 7% were observed between PB and eMC algorithms. Monitor unit calculations were also preformed

  17. Genetic algorithms

    NASA Technical Reports Server (NTRS)

    Wang, Lui; Bayer, Steven E.

    1991-01-01

    Genetic algorithms are mathematical, highly parallel, adaptive search procedures (i.e., problem solving methods) based loosely on the processes of natural genetics and Darwinian survival of the fittest. Basic genetic algorithms concepts are introduced, genetic algorithm applications are introduced, and results are presented from a project to develop a software tool that will enable the widespread use of genetic algorithm technology.

  18. Comparative Study of Impedance Eduction Methods. Part 1; DLR Tests and Methodology

    NASA Technical Reports Server (NTRS)

    Busse-Gerstengarbe, Stefan; Bake, Friedrich; Enghardt, Lars; Jones, Michael G.

    2013-01-01

    The absorption efficiency of acoustic liners used in aircraft engines is characterized by the acoustic impedance. World wide, many grazing ow test rigs and eduction methods are available that provide values for that impedance. However, a direct comparison and assessment of the data of the di erent rigs and methods is often not possible because test objects and test conditions are quite di erent. Only a few papers provide a direct comparison. Therefore, this paper together with a companion paper, present data measured with a reference test object under similar conditions in the DLR and NASA grazing ow test rigs. Additionally, by applying the in-house methods Liner Impedance Non-Uniform ow Solving algorithm (LINUS, DLR) and Convected Helmhholtz Equation approach (CHE, NASA) on the data sets, similarities and differences due to underlying theory are identi ed and discussed.

  19. Optimization of Microphone Locations for Acoustic Liner Impedance Eduction

    NASA Technical Reports Server (NTRS)

    Jones, M. G.; Watson, W. R.; June, J. C.

    2015-01-01

    Two impedance eduction methods are explored for use with data acquired in the NASA Langley Grazing Flow Impedance Tube. The first is an indirect method based on the convected Helmholtz equation, and the second is a direct method based on the Kumaresan and Tufts algorithm. Synthesized no-flow data, with random jitter to represent measurement error, are used to evaluate a number of possible microphone locations. Statistical approaches are used to evaluate the suitability of each set of microphone locations. Given the computational resources required, small sample statistics are employed for the indirect method. Since the direct method is much less computationally intensive, a Monte Carlo approach is employed to gather its statistics. A comparison of results achieved with full and reduced sets of microphone locations is used to determine which sets of microphone locations are acceptable. For the indirect method, each array that includes microphones in all three regions (upstream and downstream hard wall sections, and liner test section) provides acceptable results, even when as few as eight microphones are employed. The best arrays employ microphones well away from the leading and trailing edges of the liner. The direct method is constrained to use microphones opposite the liner. Although a number of arrays are acceptable, the optimum set employs 14 microphones positioned well away from the leading and trailing edges of the liner. The selected sets of microphone locations are also evaluated with data measured for ceramic tubular and perforate-over-honeycomb liners at three flow conditions (Mach 0.0, 0.3, and 0.5). They compare favorably with results attained using all 53 microphone locations. Although different optimum microphone locations are selected for the two impedance eduction methods, there is significant overlap. Thus, the union of these two microphone arrays is preferred, as it supports usage of both methods. This array contains 3 microphones in the upstream

  20. An Electrochemical Impedance Spectroscopy System for Monitoring Pineapple Waste Saccharification

    PubMed Central

    Conesa, Claudia; Ibáñez Civera, Javier; Seguí, Lucía; Fito, Pedro; Laguarda-Miró, Nicolás

    2016-01-01

    Electrochemical impedance spectroscopy (EIS) has been used for monitoring the enzymatic pineapple waste hydrolysis process. The system employed consists of a device called Advanced Voltammetry, Impedance Spectroscopy & Potentiometry Analyzer (AVISPA) equipped with a specific software application and a stainless steel double needle electrode. EIS measurements were conducted at different saccharification time intervals: 0, 0.75, 1.5, 6, 12 and 24 h. Partial least squares (PLS) were used to model the relationship between the EIS measurements and the sugar determination by HPAEC-PAD. On the other hand, artificial neural networks: (multilayer feed forward architecture with quick propagation training algorithm and logistic-type transfer functions) gave the best results as predictive models for glucose, fructose, sucrose and total sugars. Coefficients of determination (R2) and root mean square errors of prediction (RMSEP) were determined as R2 > 0.944 and RMSEP < 1.782 for PLS and R2 > 0.973 and RMSEP < 0.486 for artificial neural networks (ANNs), respectively. Therefore, a combination of both an EIS-based technique and ANN models is suggested as a promising alternative to the traditional laboratory techniques for monitoring the pineapple waste saccharification step. PMID:26861317

  1. System for simultaneous measurements of bilaterally symmetrical acupoints multifrequency impedances

    PubMed Central

    Su, Mi-Yong; Tan, Yong-Hong; Wang, Zi-Min; Gan, Cai-Jun; Chen, Shou-Hong

    2013-01-01

    Devices which can obtain comparable bilaterally symmetrical acupoints (BSA) multifrequency impedances (MFI) are often needed in the detection of the energy balance states of acupoints in traditional Chinese medicine. To satisfy these needs, a two-channel impedance measurement system has been introduced which is capable of accurately and simultaneously measuring BSA MFI. The system includes a set of five electrodes, two of which are injected with exciting current signal to synchronously and equally excite BSA; the other three electrodes are used as sensors to simultaneously sense the response signal from both sides. The system also includes a PC-based time-domain signal testing platform with arbitrary current waveform generation and three channels (one exciting current and two response voltages) simultaneously sampling, and a set of MFI simultaneously unbiased computing algorithms based on special odd multisine current signal input. Preliminary validating experiments suggest that the system allows accurate and synchronous measurement of BSA MFI at least in the frequency range of 10 Hz to 60 kHz, and the obtained BSA MFI are well comparable. PMID:24348077

  2. An Electrochemical Impedance Spectroscopy System for Monitoring Pineapple Waste Saccharification.

    PubMed

    Conesa, Claudia; Ibáñez Civera, Javier; Seguí, Lucía; Fito, Pedro; Laguarda-Miró, Nicolás

    2016-01-01

    Electrochemical impedance spectroscopy (EIS) has been used for monitoring the enzymatic pineapple waste hydrolysis process. The system employed consists of a device called Advanced Voltammetry, Impedance Spectroscopy & Potentiometry Analyzer (AVISPA) equipped with a specific software application and a stainless steel double needle electrode. EIS measurements were conducted at different saccharification time intervals: 0, 0.75, 1.5, 6, 12 and 24 h. Partial least squares (PLS) were used to model the relationship between the EIS measurements and the sugar determination by HPAEC-PAD. On the other hand, artificial neural networks: (multilayer feed forward architecture with quick propagation training algorithm and logistic-type transfer functions) gave the best results as predictive models for glucose, fructose, sucrose and total sugars. Coefficients of determination (R²) and root mean square errors of prediction (RMSEP) were determined as R² > 0.944 and RMSEP < 1.782 for PLS and R² > 0.973 and RMSEP < 0.486 for artificial neural networks (ANNs), respectively. Therefore, a combination of both an EIS-based technique and ANN models is suggested as a promising alternative to the traditional laboratory techniques for monitoring the pineapple waste saccharification step. PMID:26861317

  3. Effects of Liner Geometry on Acoustic Impedance

    NASA Technical Reports Server (NTRS)

    Jones, Michael G.; Tracy, Maureen B.; Watson, Willie R.; Parrott, Tony L.

    2002-01-01

    Current aircraft engine nacelles typically contain acoustic liners consisting of perforated sheets bonded onto honeycomb cavities. Numerous models have been developed to predict the acoustic impedance of these liners in the presence of grazing flow, and to use that information with aeroacoustic propagation codes to assess nacelle liner noise suppression. Recent efforts have provided advances in impedance education methodologies that offer more accurate determinations of acoustic liner properties in the presence of grazing flow. The current report provides the results of a parametric study, in which a finite element method was used to assess the effects of variations of the following geometric parameters on liner impedance, with and without the presence of grazing flow: percent open area, sheet thickness, sheet thickness-to-hole diameter ratio and cavity depth. Normal incidence acoustic impedances were determined for eight acoustic liners, consisting of punched aluminum facesheets bonded to hexcell honeycomb cavities. Similar liners were tested in the NASA Langley Research Center grazing incidence tube to determine their response in the presence of grazing flow. The resultant data provide a quantitative assessment of the effects of these perforate, single-layer liner parameters on the acoustic impedance of the liner.

  4. Vascular impedance analysis in human pulmonary circulation.

    PubMed

    Zhou, Qinlian; Gao, Jian; Huang, Wei; Yen, Michael

    2006-01-01

    Vascular impedance is determined by morphometry and mechanical properties of the vascular system, as well as the rheology of the blood. The interactions between all these factors are complicated and difficult to investigate solely by experiments. A mathematical model representing the entire system of human pulmonary circulation was constructed based on experimentally measured morphometric and elasticity data of the vessels. The model consisted of 16 orders of arteries and 15 orders of veins. The pulmonary arteries and veins were considered as elastic tubes and their impedance was calculated based on Womersley's theory. The flow in capillaries was described by the "sheet-flow" theory. The model yielded an impedance modulus spectrum that fell steeply from a high value at 0 Hz to a minimum around 1.5 Hz. At about 4 Hz, it reached a second high and then oscillated around a relatively small value at higher frequencies. Characteristic impedance was 27.9 dyn-sec/cm5. Influence of variations in vessel geometry and elasticity on impedance spectra was analyzed. Simulation results showed good agreement with experimental measurements. PMID:16817653

  5. Non-contact scanning electrical impedance imaging.

    PubMed

    Liu, Hongze; Hawkins, Aaron; Schultz, Stephen; Oliphant, Travis

    2004-01-01

    We are interested in applying electrical impedance imaging to a single cell because it has potential to reveal both cell anatomy and cell function. Unfortunately, classic impedance imaging techniques are not applicable to this small scale measurement due to their low resolution. In this paper, a different method of impedance imaging is developed based on a non-contact scanning system. In this system, the imaging sample is immersed in an aqueous solution allowing for the use of various probe designs. Among those designs, we discuss a novel shield-probe design that has the advantage of better signal-to-noise ratio with higher resolution compared to other probes. Images showing the magnitude of current for each scanned point were obtained using this configuration. A low-frequency linear physical model helps to relate the current to the conductivity at each point. Line-scan data of high impedance contrast structures can be shown to be a good fit to this model. The first two-dimensional impedance image of biological tissues generated by this technique is shown with resolution on the order of 100 mum. The image reveals details not present in the optical image. PMID:17271931

  6. Next Generation Plasma Impedance Probe Instrumentation Technique

    NASA Astrophysics Data System (ADS)

    Carlson, C. G.; Swenson, C. M.; Fish, C.

    2003-12-01

    Four Utah State University Plasma Impedance Probes (PIP) were part of NASA's Sequential Rocket Study of Descending Layers in the E-Region (E-Winds). The payloads were launched at 11:19 pm, 1:41 am, 2:50 am and 3:07 am on June 30 and July 1, 2003 from Wallops Island, Virginia into the nighttime D and E-regions. The PIP is a suite of instruments for observing relative and absolute electron densities, magnetic field strength, and electron-neutral collision frequency. The suite consists of a Plasma Frequency Probe, a Swept Impedance Probe, a Q probe, an experimental Ion Impedance probe, and a DC Langmuir probe. The first four instrument diagnostics are based on the impedance characteristics of an antenna immersed in plasma. Resonance effects at low frequencies (1-100 kHz) where ion dynamics become important were observed by the Ion Impedance Probe. This data set may lead to the first mid-latitude measurements of ion-neutral collision frequency and full conductivity measurements of the ionosphere. Preliminary analysis of flight data shows a considerable amount of sensitivity in all of the instruments that should allow for absolute electron density measurement in the 1 to 10 per cc range and comparable accuracy in electron neutral collision frequency. This paper presents the instrumentation techniques, calibrations and initial results for this flight.

  7. Antenna pattern control using impedence surfaces

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Liu, Kefeng

    1991-01-01

    During this research period, September 16, 1990 to March 15, 1991, a design method for selecting a low-loss impedance material coating for a horn antenna pattern control has been developed. This method and the stepped waveguide technique can be employed to accurately compute the electromagnetic wave phenomenon inside the transition region of the horn antenna, with or without the impedance surfaces, from the feed to the radiating aperture. For moment method solutions of the electric and magnetic current distributions on the radiating aperture and the outer surface of the horn antenna, triangular surface-patch modes are introduced to replace the sinusoidal surface-patch modes as expansion and testing functions to provide a more physical expansion of the current distributions. In the synthesis problem, a numerical optimization process is formulated to minimize the error function between the desired waveguide modes and the modes provided by the horn transition with impedance surfaces. Since the modes generated by the horn transition with impedance surface are computed by analytical techniques, the computational error involved in the synthesis of the antenna pattern is minimum. Therefore, the instability problem can be avoided. A preliminary implementation of the techniques has demonstrated that the developed theory of the horn antenna pattern control using the impedance surfaces is realizable.

  8. Tunable microwave impedance matching to a high impedance source using a Josephson metamaterial

    SciTech Connect

    Altimiras, Carles Parlavecchio, Olivier; Joyez, Philippe; Vion, Denis; Roche, Patrice; Esteve, Daniel; Portier, Fabien

    2013-11-18

    We report the efficient coupling of a 50  Ω microwave circuit to a high impedance conductor. We use an impedance transformer consisting of a λ/4 co-planar resonator whose inner conductor contains an array of superconducting quantum interference devices (SQUIDs), providing it with a tunable lineic inductance L∼80 μ{sub 0}, resulting in a characteristic impedance Z{sub C}∼1 kΩ. The impedance matching efficiency is characterized by measuring the shot noise power emitted by a dc biased tunnel junction connected to the resonator. We demonstrate matching to impedances in the 15 to 35 kΩ range with bandwidths above 100 MHz around a resonant frequency tunable between 4 and 6 GHz.

  9. Tunable microwave impedance matching to a high impedance source using a Josephson metamaterial

    NASA Astrophysics Data System (ADS)

    Altimiras, Carles; Parlavecchio, Olivier; Joyez, Philippe; Vion, Denis; Roche, Patrice; Esteve, Daniel; Portier, Fabien

    2013-11-01

    We report the efficient coupling of a 50 Ω microwave circuit to a high impedance conductor. We use an impedance transformer consisting of a λ/4 co-planar resonator whose inner conductor contains an array of superconducting quantum interference devices (SQUIDs), providing it with a tunable lineic inductance L ˜80 μ0, resulting in a characteristic impedance ZC˜1 k Ω. The impedance matching efficiency is characterized by measuring the shot noise power emitted by a dc biased tunnel junction connected to the resonator. We demonstrate matching to impedances in the 15 to 35 kΩ range with bandwidths above 100 MHz around a resonant frequency tunable between 4 and 6 GHz.

  10. Inversion without Explicit Jacobian Calculations in Electrical Impedance Tomography

    NASA Astrophysics Data System (ADS)

    Fouchard, A.; Bonnet, S.; Hervé, L.; David, O.

    2014-10-01

    Electrical impedance tomography (EIT) is the inverse problem of finding the internal conductivity distribution of a medium given boundary electrical measurements performed via an electrode array onto its surface. Conventional inversion schemes adopt Tikhonov regularized Newton-type methods. Following a transport back-transport approach, we develop in this work an adjoint approach which allows reducing computational burden in enabling inversion without explicit Jacobian calculation. Forward and back-projection operators are defined from potential gradients, along with their efficient implementation. These derivations allow the transparent use of inversion algorithms. We first check the implementation of operators. We then evaluate how reconstructions perform on simulated noisy data using a preconditioned conjugate gradient. We eventually practice our inversion framework on experimental data acquired in vitro from a saline phantom.

  11. Comparison of a Convected Helmholtz and Euler Model for Impedance Eduction in Flow

    NASA Technical Reports Server (NTRS)

    Watson, Willie R.; Jones, Michael G.

    2006-01-01

    Impedances educed from a well-tested convected Helmholtz model are compared to that of a recently developed linearized Euler model using two ceramic test liners under the assumed conditions or uniform flow and a plane wave source. The convected Helmholtz model is restricted to uniform mean flow whereas the linearized Euler model can account for the effect or the shear layer. Test data to educe the impedance is acquired from measurements obtained in the NASA Langley Research Center Grazing Incidence Tube for mean flow Mach numbers ranging from 0.0 to 0.5 and source frequencies ranging from 0.5 kHz to 3.0 kHz. The unknown impedance of the liner b educed by judiciously chooingth e impedance via an optimization method to match the measured acoustic pressure on the wall opposite the test liner. Results are presented on four spatial grids using three different optimization methods (contour deformation, Davidon-Fletcher Powell, and the Genetic Algorithm). All three optimization methods converge to the same impedance when used with the same model and to nearly identical impedances when used on different models. h anomaly was observed only at 0.5 kHz for high mean flow speeds. The anomaly is likely due to the use of measured data in a flow regime where shear layer effects are important but are neglected in the math models. Consistency between the impedances educed using the two models provides confidence that the linearized Euler model is ready For application to more realistic flows, such as those containing shear layers.

  12. Propagation of waves along an impedance boundary

    NASA Technical Reports Server (NTRS)

    Wenzel, A. R.

    1974-01-01

    A theoretical analysis of the scalar wave field due to a point source above a plane impedance boundary is presented. A surface wave is found to be an essential component of the total wave field. It is shown that, as a result of ducting of energy by the surface wave, the amplitude of the total wave near the boundary can be greater than it would be if the boundary were perfectly reflecting. Asymptotic results, valid near the boundary, are obtained both for the case of finite impedance (the soft-boundary case) and for the limiting case in which the impedance becomes infinite (the hard-boundary case). In the latter, the wave amplitude in the farfield decreases essentially inversely as the horizontal propagation distance; in the former (if the surface-wave term is neglected), it decreases inversely as the square of the horizontal propagation distance.

  13. Ferrofluid Microwave Devices With Magnetically Controlled Impedances

    NASA Astrophysics Data System (ADS)

    Fannin, P. C.; Stefu, N.; Marin, C. N.; Malaescu, I.; Totoreanu, R.

    2010-08-01

    Ferrofluid filled transmission lines are microwave electronic devices. The complex dielectric permittivity and the complex magnetic permeability of a kerosene based ferrofluid with magnetite nanoparticles, in the frequency range (0.5-6) GHz were measured, for several values of polarising field, H. Afterwards, the input impedance of a short-circuited transmission line filled with this ferrofluid was computed using the equation Z = Zc tanh(γl). Here Zc and l are the characteristic impedance and the length of the coaxial line and γ is the propagation constant, depending on the dielectric and magnetic parameters of the material within the line. It is demonstrated how the impedance displays a frequency and polarizing field dependence, which has application in the design of magnetically controlled microwave devices.

  14. Respiratory acoustic impedance in left ventricular failure.

    PubMed

    Depeursinge, F B; Feihl, F; Depeursinge, C; Perret, C H

    1989-12-01

    The measurement of respiratory acoustic impedance (Zrs) by forced pseudorandom noise provides a simple means of assessing respiratory mechanics in nonintubated intensive care patients. To characterize the lung mechanical alterations induced by acute vascular congestion of the lung, Zrs was measured in 14 spontaneously breathing patients hospitalized for acute left ventricular failure. The Zrs data in the cardiac patients were compared with those of 48 semirecumbent normal subjects and those of 23 sitting asthmatic patients during allergen-induced bronchospasm. In the patients with acute left ventricular failure, the Zrs abnormalities noted were an excessive frequency dependence of resistance from 10 to 20 Hz and an abnormally low reactance at all frequencies, abnormalities qualitatively similar to those observed in the asthmatic patients but of lesser magnitude. Acute lung vascular congestion modifies the acoustic impedance of the respiratory system. Reflex-induced bronchospasm might be the main mechanism altering respiratory acoustic impedance in acute left ventricular failure. PMID:2582846

  15. Plasma Diagnostics by Antenna Impedance Measurements

    NASA Technical Reports Server (NTRS)

    Swenson, C. M.; Baker, K. D.; Pound, E.; Jensen, M. D.

    1993-01-01

    The impedance of an electrically short antenna immersed in a plasma provides an excellent in situ diagnostic tool for electron density and other plasma parameters. By electrically short we mean that the wavelength of the free-space electromagnetic wave that would be excited at the driving frequency is much longer than the physical size of the antenna. Probes using this impedance technique have had a long history with sounding rockets and satellites, stretching back to the early 1960s. This active technique could provide information on composition and temperature of plasmas for comet or planetary missions. Advantages of the impedance probe technique are discussed and two classes of instruments built and flown by SDL-USU for determining electron density (the capacitance and plasma frequency probes) are described.

  16. Impedance properties of circular microstrip antenna

    NASA Technical Reports Server (NTRS)

    Deshpande, M. D.; Bailey, M. C.

    1983-01-01

    A moment method solution to the input impedance of a circular microstrip antenna excited by either a microstrip feed or a coaxial probe is presented. Using the exact dyadic Green's function and the Fourier transform the problem is formulated in terms of Richmond's reaction integral equation from which the unknown patch current can be solved for. The patch current is expanded in terms of regular surface patch modes and an attachment mode (for probe excited case) which insures continuity of the current at probe/patch junction, proper polarization and p-dependance of patch current in the vicinity of the probe. The input impedance of a circular microstrip antenna is computed and compared with earlier results. Effect of attachment mode on the input impedance is also discussed.

  17. Impedance Characteristics of the Plasma Absorption Probe

    NASA Astrophysics Data System (ADS)

    Yamazawa, Yohei

    2009-10-01

    The plasma absorption probe (PAP) is a diagnostics for determination of spatially resolved electron density.footnotetextH. Kokura, et al., Jpn. J. Appl. Phys. 38 5262 (1999). PAP has attracted considerable interest because of its applicability in a reactive plasma. The simple structure of the probe allows us a robust measurement while the mechanism of the absorption is complicated and there are still some uncertainty.footnotetextM. Lapke, et al., Appl. Phys. Lett. 90, 121502 (2007) In this study, we focus on the frequency characteristics of the impedance instead of the absorption spectrum. An electromagnetic field simulation reveals that there is only one parallel resonance in the impedance characteristics even in a case there are many peaks in absorption spectrum. Thus, the impedance characteristics provide a clue to understanding the mechanism.

  18. Design of a wearable perturbator for human knee impedance estimation during gait.

    PubMed

    Tucker, Michael R; Moser, Adrian; Lambercy, Olivier; Sulzer, James; Gassert, Roger

    2013-06-01

    Mechanical impedance modulation is the key to natural, stable and efficient human locomotion. An improved understanding of this mechanism is necessary for the development of the next generation of intelligent prosthetic and orthotic devices. This paper documents the design methodologies that were employed to realize a knee perturbator that can experimentally estimate human knee impedance during gait through the application of angular velocity perturbations. The proposed experiment requires a light, transparent, wearable, and remotely actuated device that closely follows the movement of the biological joint. A genetic algorithm was used to design a polycentric hinge whose instantaneous center of rotation is optimized to be kinematically compatible with the human knee. A wafer disc clutch was designed to switch between a high transparency passive mode and a high impedance actuated mode. A remote actuation and transmission scheme was designed to enable high power output perturbations while minimizing the device's mass. Position and torque sensors were designed for device control and to provide data for post-processing and joint impedance estimation. Pending the fabrication and mechanical testing of the device, we expect this knee perturbator to be a valuable tool for experimental investigation of locomotive joint impedance modulation. PMID:24187191

  19. Evaluation of a multi-point method for determining acoustic impedance

    NASA Technical Reports Server (NTRS)

    Jones, Michael G.; Parrott, Tony L.

    1988-01-01

    An investigation was conducted to explore potential improvements provided by a Multi-Point Method (MPM) over the Standing Wave Method (SWM) and Two-Microphone Method (TMM) for determining acoustic impedance. A wave propagation model was developed to model the standing wave pattern in an impedance tube. The acoustic impedance of a test specimen was calculated from a best fit of this standing wave pattern to pressure measurements obtained along the impedance tube centerline. Three measurement spacing distributions were examined: uniform, random, and selective. Calculated standing wave patterns match the point pressure measurement distributions with good agreement for a reflection factor magnitude range of 0.004 to 0.999. Comparisons of results using 2, 3, 6, and 18 measurement points showed that the most consistent results are obtained when using at least 6 evenly spaced pressure measurements per half-wavelength. Also, data were acquired with broadband noise added to the discrete frequency noise and impedances were calculated using the MPM and TMM algorithms. The results indicate that the MPM will be superior to the TMM in the presence of significant broadband noise levels associated with mean flow.

  20. Optical input impedance of nanostrip antennas

    NASA Astrophysics Data System (ADS)

    Wang, Ivan; Du, Ya-ping

    2012-05-01

    We conduct an investigation into optical nanoantennas in the form of a strip dipole made from aluminum. With the finite-difference time domain simulation both optical input impedance and radiation efficiency of nanostrip antennas are addressed. An equivalent circuit is presented as well for the nanostrip antennas at optical resonances. The optical input resistance can be adjusted by varying the geometric parameters of antenna strips. By changing both strip area and strip length simultaneously, optical input resistance can be adjusted for matching impedance with an external feeding or loading circuit. It is found that the optical radiation efficiency does not change significantly when the size of a nanostrip antenna varies moderately.

  1. Protein Aggregation Measurement through Electrical Impedance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Affanni, A.; Corazza, A.; Esposito, G.; Fogolari, F.; Polano, M.

    2013-09-01

    The paper presents a novel methodology to measure the fibril formation in protein solutions. We designed a bench consisting of a sensor having interdigitated electrodes, a PDMS hermetic reservoir and an impedance meter automatically driven by calculator. The impedance data are interpolated with a lumped elements model and their change over time can provide information on the aggregation process. Encouraging results have been obtained by testing the methodology on K-casein, a protein of milk, with and without the addition of a drug inhibiting the aggregation. The amount of sample needed to perform this measurement is by far lower than the amount needed by fluorescence analysis.

  2. Study of Body Composition by Impedance Analysis

    NASA Astrophysics Data System (ADS)

    González-Solís, J. L.; Vargas-Luna, M.; Sosa-Aquino, M.; Bernal-Alvarado, J.; Gutiérrez-Juárez, G.; Huerta-Franco, R.; Sanchis-Sabater, A.

    2002-08-01

    This work presents a set of impedance measurements and preliminary results on the analysis of body composition using impedance spectroscopy. This study is made using a pork meat sample and spectra from fat and flesh region were independently obtained using the same electrodes array. From these measurements, and theoretical considerations, it is possible to explain the behavior of the composite sample flesh-fat-flesh and, fitting the electrical parameters of the model, it shows the plausibility of a physical and quantitative application to human corporal composition.

  3. Impedance spectra of polypyrrole coated platinum electrodes.

    PubMed

    Onnela, Niina; Savolainen, Virpi; Hiltunen, Maiju; Kellomäki, Minna; Hyttinen, Jari

    2013-01-01

    Polypyrrole (PPy) coated electrodes may provide new solutions to increase the charge injection capacity and biocompatibility of metal electrodes in e.g., neural stimulus applications. In this study, electrical impedance spectra of PPy coated platinum (Pt) electrodes having three different coating thicknesses were measured and modeled. A suitable equivalent electrical circuit providing the material characteristics was chosen and the impedance data was analyzed using the model and data fitting. The modeled parameter values of different coating thicknesses were compared and our results demonstrated the changes in charge transfer properties and mechanisms of thin and thick PPy film coatings. PMID:24109743

  4. Electrochemical Impedance Spectroscopy Of Metal Alloys

    NASA Technical Reports Server (NTRS)

    Macdowell, L. G.; Calle, L. M.

    1993-01-01

    Report describes use of electrochemical impedance spectroscopy (EIS) to investigate resistances of 19 alloys to corrosion under conditions similar to those of corrosive, chloride-laden seaside environment of Space Transportation System launch site. Alloys investigated: Hastelloy C-4, C-22, C-276, and B-2; Inconel(R) 600, 625, and 825; Inco(R) G-3; Monel 400; Zirconium 702; Stainless Steel 304L, 304LN, 316L, 317L, and 904L; 20Cb-3; 7Mo+N; ES2205; and Ferralium 255. Results suggest electrochemical impedance spectroscopy used to predict corrosion performances of metal alloys.

  5. Hole-Impeded-Doping-Superlattice LWIR Detectors

    NASA Technical Reports Server (NTRS)

    Maserjian, Joseph

    1991-01-01

    Hole-Impeded-Doping-Superlattice (HIDS) InAs devices proposed for use as photoconductive or photovoltaic detectors of radiation in long-wavelength infrared (LWIR) range of 8 to 17 micrometers. Array of HIDS devices fabricated on substrates GaAs or Si. Radiation incident on black surface, metal contacts for picture elements serve as reactors, effectively doubling optical path and thereby increasing absorption of photons. Photoconductive detector offers advantages of high gain and high impedance; photovoltaic detector offers lower noise and better interface to multiplexer readouts.

  6. Impedance Scaling for Small Angle Transitions

    SciTech Connect

    Stupakov, G.; Bane, Karl; Zagorodnov, I.; /DESY

    2010-10-27

    Based on the parabolic equation approach to Maxwell's equations we have derived scaling properties of the high frequency impedance/short bunch wakefields of structures. For the special case of small angle transitions we have shown the scaling properties are valid for all frequencies. Using these scaling properties one can greatly reduce the calculation time of the wakefield/impedance of long, small angle, beam pipe transitions, like one often finds in insertion regions of storage rings. We have tested the scaling with wakefield simulations of 2D and 3D models of such transitions, and found that the scaling works well. In modern ring-based light sources one often finds insertion devices having extremely small vertical apertures (on the order of millimeters) to allow for maximal undulator fields reaching the beam. Such insertion devices require that there be beam pipe transitions from these small apertures to the larger cross-sections (normally on the order of centimeters) found in the rest of the ring. The fact that there may be many such transitions, and that these transitions introduce beam pipe discontinuities very close to the beam path, means that their impedance will be large and, in fact, may dominate the impedance budget of the entire ring. To reduce their impact on impedance, the transitions are normally tapered gradually over a long distance. The accurate calculation of the impedance or wakefield of these long transitions, which are typically 3D objects (i.e. they do not have cylindrical symmetry), can be quite a challenging numerical task. In this report we present a method of obtaining the impedance of a long, small angle transition from the calculation of a scaled, shorter one. Normally, the actual calculation is obtained from a time domain simulation of the wakefield in the structure, where the impedance can be obtained by performing a Fourier transform. We shall see that the scaled calculation reduces the computer time and memory requirements

  7. Implementation of Impedance Method in Syncope Treatment

    NASA Astrophysics Data System (ADS)

    Pęczalski, Kazimierz; Wojciechowski, Dariusz; Dunajski, Zbigniew; Pałko, Tadeusz

    2007-01-01

    Current syncope treatment by cardiac pacing is limited to patients developing cardiodepressive reaction. There is strong need to apply this method to other types of reaction. Presented method shows, that impedance method can be applied for early detection of vasodepressive syncope. Thus the method can be applied for antivasovagal pacing in syncopic patients.

  8. Acoustic grazing flow impedance using waveguide principles

    NASA Technical Reports Server (NTRS)

    Armstrong, D. L.

    1971-01-01

    A grazing flow apparatus was designed to measure the impedance of acoustic materials when installed in environments that subject the material to grazing airflow. The design of the apparatus and the data analysis technique is based on the solution of the convected wave equation in an infinite length waveguide.

  9. Electrical Impedance Tomography Technology (EITT) Project

    NASA Technical Reports Server (NTRS)

    Oliva-Buisson, Yvette J.

    2014-01-01

    Development of a portable, lightweight device providing two-dimensional tomographic imaging of the human body using impedance mapping. This technology can be developed to evaluate health risks and provide appropriate medical care on the ISS, during space travel and on the ground.

  10. Energy-storage of a prescribed impedance

    NASA Technical Reports Server (NTRS)

    Smith, W. E.

    1969-01-01

    General mathematical expression found for energy storage shows that for linear, passive networks there is a minimum possible energy storage corresponding to a prescribed impedance. The electromagnetic energy storage is determined at different excitation frequencies through analysis of the networks terminal and reactance characteristics.

  11. Explicit Expressions of Impedances and Wake Functions

    SciTech Connect

    Ng, K.Y.; Bane, K,; /SLAC

    2012-06-11

    Sections 3.2.4 and 3.2.5 of the Handbook of Accelerator Physics and Engineering on Landau damping are combined and updated. The new addition includes impedances and wakes for multi-layer beam pipe, optical model, diffraction model, and cross-sectional transition.

  12. Explicit expressions of impedances and wake functions

    SciTech Connect

    Ng, K.Y.; Bane, K,; /SLAC

    2010-10-01

    Sections 3.2.4 and 3.2.5 of the Handbook of Accelerator Physics and Engineering on Landau damping are combined and updated. The new addition includes impedances and wakes for multi-layer beam pipe, optical model, diffraction model, and cross-sectional transition.

  13. Bioelectrical Impedance and Body Composition Assessment

    ERIC Educational Resources Information Center

    Martino, Mike

    2006-01-01

    This article discusses field tests that can be used in physical education programs. The most common field tests are anthropometric measurements, which include body mass index (BMI), girth measurements, and skinfold testing. Another field test that is gaining popularity is bioelectrical impedance analysis (BIA). Each method has particular strengths…

  14. Impedance-matched drilling telemetry system

    DOEpatents

    Normann, Randy A.; Mansure, Arthur J.

    2008-04-22

    A downhole telemetry system that uses inductance or capacitance as a mode through which signal is communicated across joints between assembled lengths of pipe wherein efficiency of signal propagation through a drill string, for example, over multiple successive pipe segments is enhanced through matching impedances associated with the various telemetry system components.

  15. High Impedance Comparator for Monitoring Water Resistivity.

    ERIC Educational Resources Information Center

    Holewinski, Paul K.

    1984-01-01

    A high-impedance comparator suitable for monitoring the resistivity of a deionized or distilled water line supplying water in the 50 Kohm/cm-2 Mohm/cm range is described. Includes information on required circuits (with diagrams), sensor probe assembly, and calibration techniques. (JN)

  16. Recurrence of chest wall hydatid cyst disease involving the thoracic spine in an Australian patient.

    PubMed

    Mon, Su Thet; Li, Yingda; Shepherd, Sarah; Daniel, Santosh; Poonnoose, Santosh; McDonald, Matthew

    2016-08-01

    Hydatid disease involving the spine is a relatively uncommon occurrence. The cestode Echinococcus granulosus is the primary pathogen associated with hydatid disease and most patients present with signs and symptoms of spinal cord compression depending on the location of the spinal involvement. We present a rare case of recurrent hydatid disease with extensive hemithorax involvement, including the thoracic spine, associated with spinal cord compression. This case highlights the role of staged and minimally invasive spine surgery in spinal hydatid disease with spinal cord compression, the importance of ongoing medical treatment and long term follow-up. PMID:27050921

  17. Chest wall shrapnel-induced beryllium-sensitization and associated pulmonary disease.

    PubMed

    Fireman, E; Shai, A Bar; Lerman, Y; Topilsky, M; Blanc, P D; Maier, L; Li, L; Chandra, S; Abraham, J M; Fomin, I; Aviram, G; Abraham, J L

    2012-10-01

    Chronic beryllium disease (CBD) is an exposure-related granulomatous disease mimicking sarcoidosis. Beryllium exposure-associated disease occurs mainly via inhalation, but skin may also be a source of sensitization. A 65-year-old male with a history of war-related shrapnel wounds was initially diagnosed with pulmonary sarcoidosis. Twenty years later, the possibility of a metal-related etiology for the lung disease was raised. A beryllium lymphocyte proliferation test, elemental analysis of removed shrapnel, and genetic studies were consistent with a diagnosis of CBD. This case demonstrates that retained beryllium-containing foreign bodies can be linked to a pathophysiologic response in the lung consistent with CBD. PMID:23461078

  18. Recurrent pseudoaneurysm of the left ventricle with subcutaneous herniation into the chest wall. A case report.

    PubMed Central

    Rao, M S; Vaijyanath, P; Taneja, K; Dubey, B; Manchanda, S C; Venugopal, P

    1998-01-01

    Pseudoaneurysm of the left ventricle is rare, and recurrence is extremely rare. We report the case of a 62-year-old man who presented at our hospital with a painless pulsatile swelling in the left breast. He had undergone coronary artery bypass grafting and left-ventricular aneurysmectomy 14 years earlier. On investigation, the swelling was diagnosed to be a pseudoaneurysm of the left ventricle with subcutaneous herniation. The extreme rarity of this condition prompted us to report the case. The investigative techniques and the surgical strategy are discussed. Images PMID:9885110

  19. Anterior chest wall elevation using a T-fastener suture technique during a Nuss procedure.

    PubMed

    Kim, Daabin; Idowu, Olajire; Palmer, Barnard; Kim, Sunghoon

    2014-08-01

    The most critical part of the Nuss procedure is the passage of the introducer across the anterior mediastinum without cardiac injury. For patients with severe pectus excavatum, passing the introducer can be difficult and hazardous. We describe a technique that resembles a use of T-fastenerlike suture material to elevate the anterior chest. The elevation of the chest allows safe, blunt anterior mediastinal dissection before the passage of the introducer. The risk of intraoperative cardiac perforation is minimized. PMID:25087810

  20. Myxoid mesenchymal neoplasm presenting as massive arm and chest wall oedema with pleural effusion

    PubMed Central

    Pai, Vidya B; Ravilla, Rahul; Lindberg, Matthew; Steliga, Matthew; Arnaoutakis, Konstantinos

    2015-01-01

    Myxoid mesenchymal tumours are a heterogeneous group of neoplasms characterised histologically by their abundant mucoid and myxoid extracellular matrix (ECM). Encompassing a broad spectrum of clinical behaviour ranging from benign to malignant, there are more than 60 reactive and neoplastic entities currently classified under its domain. Its varied clinical and histopathologic features continue to pose a diagnostic challenge to clinicians and pathologists. Here, we describe a rare case of myxoid mesenchymal tumour presenting as oedema of the upper extremity with pleural metastasis and partial response to chemotherapy, which to the best of our knowledge has not yet been described in the literature. PMID:26635894

  1. Aortic Input Impedance during Nitroprusside Infusion

    PubMed Central

    Pepine, Carl J.; Nichols, W. W.; Curry, R. C.; Conti, C. Richard

    1979-01-01

    Beneficial effects of nitroprusside infusion in heart failure are purportedly a result of decreased afterload through “impedance” reduction. To study the effect of nitroprusside on vascular factors that determine the total load opposing left ventricular ejection, the total aortic input impedance spectrum was examined in 12 patients with heart failure (cardiac index <2.0 liters/min per m2 and left ventricular end diastolic pressure >20 mm Hg). This input impedance spectrum expresses both mean flow (resistance) and pulsatile flow (compliance and wave reflections) components of vascular load. Aortic root blood flow velocity and pressure were recorded continuously with a catheter-tip electromagnetic velocity probe in addition to left ventricular pressure. Small doses of nitroprusside (9-19 μg/min) altered the total aortic input impedance spectrum as significant (P < 0.05) reductions in both mean and pulsatile components were observed within 60-90 s. With these acute changes in vascular load, left ventricular end diastolic pressure declined (44%) and stroke volume increased (20%, both P < 0.05). Larger nitroprusside doses (20-38 μg/min) caused additional alteration in the aortic input impedance spectrum with further reduction in left ventricular end diastolic pressure and increase in stroke volume but no additional changes in the impedance spectrum or stroke volume occurred with 39-77 μg/min. Improved ventricular function persisted when aortic pressure was restored to control values with simultaneous phenylephrine infusion in three patients. These data indicate that nitroprusside acutely alters both the mean and pulsatile components of vascular load to effect improvement in ventricular function in patients with heart failure. The evidence presented suggests that it may be possible to reduce vascular load and improve ventricular function independent of aortic pressure reduction. PMID:457874

  2. Frequency-difference electrical impedance tomography: Phantom imaging experiments

    NASA Astrophysics Data System (ADS)

    Ahn, Sujin; Jun, Sung Chan; Seo, Jin Keun; Lee, Jeehyun; Woo, Eung Je; Holder, David

    2010-04-01

    Frequency-difference electrical impedance tomography (fdEIT) using a weighted voltage difference has been proposed as a means to provide images of admittivity changes at different frequencies. This weighted difference method is an effective way to extract anomaly information while eliminating background effects by unknown boundary geometry, uncertainty in electrode positions and other systematic measurement artefacts. It also properly handles the interplay between conductivity and permittivity in measured boundary voltage data. Though the proposed fdEIT algorithm is promising for applications such as detection of hemorrhagic stroke and breast cancer, more validation studies are needed. In this paper, we performed two-and three-dimensional numerical simulations and phantom experiments. Backgrounds of imaging objects were either saline or carrot pieces suspended in saline. We used carrot pieces to simulate a more realistic frequency-dependent admittivity distribution. Test objects were banana, potato or conductive gel with known admittivity spectra. When the background was saline, both simple and weighted difference approaches produced reasonably accurate images. The weighted difference method yielded better images from two-dimensional imaging objects with background of carrot pieces. For the three-dimensional head-shaped phantom, the advantage of the weighted frequency difference method over the simple difference method is not as obvious as in the case of the two-dimensional phantom. It is unclear if this is due to measurement errors or limitations in the linear algorithm. Further refinement and validation of the frequency difference image reconstructions are currently in progress.

  3. Scattering by a groove in an impedance plane

    NASA Technical Reports Server (NTRS)

    Bindiganavale, Sunil; Volakis, John L.

    1993-01-01

    An analysis of two-dimensional scattering from a narrow groove in an impedance plane is presented. The groove is represented by a impedance surface and the problem reduces to that of scattering from an impedance strip in an otherwise uniform impedance plane. On the basis of this model, appropriate integral equations are constructed using a form of the impedance plane Green's functions involving rapidly convergent integrals. The integral equations are solved by introducing a single basis representation of the equivalent current on the narrow impedance insert. Both transverse electric (TE) and transverse magnetic (TM) polarizations are treated. The resulting solution is validated by comparison with results from the standard boundary integral method (BIM) and a high frequency solution. It is found that the presented solution for narrow impedance inserts can be used in conjunction with the high frequency solution for the characterization of impedance inserts of any given width.

  4. Inter-Changeability of Impedance Devices for Lymphedema Assessment.

    PubMed

    van Zanten, Malou; Piller, Neil; Ward, Leigh C

    2016-06-01

    Impedance technology is a popular technique for the early detection of lymphedema. The preferred approach is to use bioimpedance spectroscopy (BIS), with measurements being made with the subject lying supine, although attempts have been made to use single or multiple frequency impedance measurements obtained while the subject is standing. The aim of the present study was to determine the equivalence of these different approaches. Impedance measurements of the individual limbs of 37 healthy individuals were determined using both a stand-on, multi-frequency impedance device and a supine impedance spectroscopy instrument. Significant differences were found between the instruments in both absolute impedance values and, importantly, inter-limb impedance ratios. Since impedance ratios in healthy individuals provide the reference standard for detection of lymphedema, these data indicate that the methods are not interchangeable. Consideration of the errors associated with each method indicates that the BIS remains the preferred method for lymphedema detection. PMID:26574711

  5. Stimuli dependent impedance of conductive magnetorheological elastomers

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Xuan, Shouhu; Dong, Bo; Xu, Feng; Gong, Xinglong

    2016-02-01

    The structure dependent impedance of conductive magnetorheological elastomers (MREs) under different loads and magnetic fields has been studied in this work. By increasing the weight fraction of iron particles, the conductivity of the MREs increased. Dynamic mechanical measurements and synchrotron radiation x-ray computed tomography (SR-CT) were used and they provided reasons for the electrical properties changing significantly under pressure and magnetic field stimulation. The high sensitivity of MREs to external stimuli renders them suitable for application in force or magnetic field sensors. The equivalent circuit model was proposed to analyze the impedance response of MREs and it fits the experimental results very well. Each circuit component reflected the change of the inner interface under different conditions, thus relative changes in the microstructure could be distinguished. This method could be used not only to detect the structural changes in the MRE but also to provide a great deal of valuable information for the further understanding of the MR mechanism.

  6. Readout electrode assembly for measuring biological impedance

    NASA Technical Reports Server (NTRS)

    Montgomery, L. D.; Moody, D. L., Jr. (Inventor)

    1976-01-01

    The invention comprises of a pair of readout ring electrodes which are used in conjunction with apparatus for measuring the electrical impedance between different points in the body of a living animal to determine the amount of blood flow therebetween. The readout electrodes have independently adjustable diameters to permit attachment around different parts of the body between which it is desired to measure electric impedance. The axial spacing between the electrodes is adjusted by a pair of rods which have a first pair of ends fixedly attached to one electrode and a second pair of ends slidably attached to the other electrode. Indicia are provided on the outer surface of the ring electrodes and on the surface of the rods to permit measurement of the circumference and spacing between the ring electrodes.

  7. Impedance issues in the CERN SPS

    NASA Astrophysics Data System (ADS)

    Linnecar, T.

    1999-12-01

    The future use of the CERN SPS accelerator as injector for the Large Hadron Collider, LHC, and the possible use of the SPS as a neutrino source for the Gran Sasso experiment are pushing the maximum intensity requirements of the accelerator much higher than achieved up to now. At the same time the requirements on beam quality are becoming far more stringent. The SPS machine, built in the 70's, is not a "smooth" machine. It contains many discontinuities in vacuum chamber cross-section and many cavity-like objects, as well as the 5 separate RF systems at present installed. All these lead to a high impedance, seen by the beam, spread over a wide frequency range. As a result there is a constant fight against instabilities, both single and multi bunch, as the intensity increases. A program of studies is under way in the SPS to identify, reduce, and remove where possible the sources of these impedances.

  8. Impedance of a beam tube with antechamber

    SciTech Connect

    Barry, W.; Lambertson, G.R.; Voelker, F.

    1986-08-01

    A beam vacuum chamber was proposed to allow synchrotron light to radiate from a circulating electron beam into an antechamber containing photon targets, pumps, etc. To determine the impedance such a geometry would present to the beam, electromagnetic measurements were carried out on a section of chamber using for low frequencies a current-carrying wire and for up to 16 GHz, a resonance perturbation method. Because the response of such a chamber would depend on upstream and downstream restrictions of aperture yet to be determined, the resonance studies were analyzed in some generality. The favorable conclusion of these studies is that the antechamber makes practically no contribution to either the longitudinal or the transverse impedances.

  9. Automatic digital-analog impedance plethysmograph

    NASA Astrophysics Data System (ADS)

    Goy, C. B.; Mauro, K. A.; Yanicelli, L. M.; Parodi, N. F.; Gómez López, M. A.; Herrera, M. C.

    2016-04-01

    Venous occlusion plethysmography (VOP) is a traditional method widely used to assess limb blood circulation. One common mode to record VOP is by means of evaluating limb volume changes using impedance plethysmography (IP). In this paper the design and implementation of an automatic digital-analog impedance plethysmograph (ADAIP) for VOP is presented. The system is tested using precision resistances in order to calculate its repeatability. Then its global performance is assessed by means of VOP recordings on the upper and me lower limb of a healthy volunteer. The obtained repeatability was very high (95%), and the VOP recordings where the expected ones. It can be concluded that the whole system performs well and that it is suitable for automatic VOP recording.

  10. Impedance characteristics of terawatt ion diodes

    NASA Astrophysics Data System (ADS)

    Mendel, C. W., Jr.; Desjarlais, M. P.; Pointon, T. D.; Quintenz, J. P.; Rosenthal, S. E.; Seidel, D. B.; Slutz, S. A.

    Light ion fusion research has developed ion diodes that have unique properties when compared to other ion diodes. These diodes involve relativistic electrons, ion beam stagnation pressures that compress the magnetic field to the order of 10 Tesla, and large space charge and particle current effects throughout the accelerating region. These diodes have required new theories and models to account for effects that previously were unimportant. One of the most important effects of the magnetic field compression and large space charge has been impedance collapse. The impedance collapse can lead to poor energy transfer efficiency, beam debunching, and rapid change of the beam focus. The current understanding of these effects is discussed including some of the methods used to ameliorate them, and the future directions the theory and modeling will take.

  11. Enhanced Method for Cavity Impedance Calculations

    SciTech Connect

    Frank Marhauser, Robert Rimmer, Kai Tian, Haipeng Wang

    2009-05-01

    With the proposal of medium to high average current accelerator facilities the demand for cavities with extremely low Higher Order Mode (HOM) impedances is increasing. Modern numerical tools are still under development to more thoroughly predict impedances that need to take into account complex absorbing boundaries and lossy materials. With the usually large problem size it is preferable to utilize massive parallel computing when applicable and available. Apart from such computational issues, we have developed methods using available computer resources to enhance the information that can be extracted from a cavities? wakefield computed in time domain. In particular this is helpful for a careful assessment of the extracted RF power and the mitigation of potential beam break-up or emittance diluting effects, a figure of merit for the cavity performance. The method is described as well as an example of its implementation.

  12. Nonlinear acoustic impedance of thermoacoustic stack

    NASA Astrophysics Data System (ADS)

    Ge, Huan; Fan, Li; Xiao, Shu-yu; Tao, Sha; Qiu, Mei-chen; Zhang, Shu-yi; Zhang, Hui

    2012-09-01

    In order to optimize the performances of the thermoacoustic refrigerator working with the high sound pressure level, the nonlinear acoustic characteristics of the thermoacoustic stack in the resonant pipe are studied. The acoustic fluid impedance of the stack made of copper mesh and set up in a resonant pipe is measured in the acoustic fields with different intensities. It is found that when the sound pressure level in the pipe increases to a critical value, the resistance of the stack increases nonlinearly with the sound pressure, while the reactance of the stack keeps constant. Based on the experimental results, a theory model is set up to describe the acoustic characteristics of the stack, according to the rigid frame theory and Forchheimmer equation. Furthermore, the influences of the sound pressure level, operating frequency, volume porosity, and length of the stack on the nonlinear impedance of the stack are evaluated.

  13. Superconducting surface impedance under radiofrequency field

    DOE PAGESBeta

    Xiao, Binping P.; Reece, Charles E.; Kelley, Michael J.

    2013-04-26

    Based on BCS theory with moving Cooper pairs, the electron states distribution at 0K and the probability of electron occupation with finite temperature have been derived and applied to anomalous skin effect theory to obtain the surface impedance of a superconductor under radiofrequency (RF) field. We present the numerical results for Nb and compare these with representative RF field-dependent effective surface resistance measurements from a 1.5 GHz resonant structure.

  14. Equivalent impedance of a rough interface

    NASA Astrophysics Data System (ADS)

    Zhuk, N. P.; Tret'iakov, O. A.

    1987-10-01

    An equivalent-impedance (EI) dyad is constructed for a rough and plane (on the average) interface dividing two plane-stratified magnetodielectric media. Its characteristics are related to those of a smooth surface and to the scattering properties of the roughnesses. It is shown that the Hermitian part of an EI dyad is formed through field scattering by roughnesses into the propagating natural modes of the regular medium.

  15. Impedance analysis of nanocarbon DSSC electrodes

    NASA Astrophysics Data System (ADS)

    Gagliardi, S.; Giorgi, L.; Giorgi, R.; Lisi, N.; Dikonimos Makris, Th.; Salernitano, E.; Rufoloni, A.

    2009-07-01

    Carbon nanoparticles and multiwall carbon nanotubes were deposited on an Optically Transparent Electrode (OTE) for application in Dye Sensitised Solar Cells (DSSCs) as counter electrode materials. Electrochemical Impedance Spectroscopy (EIS) was used to evaluate the behaviour in a I3-/I electrolyte solution. Results were compared to commercial Pt catalysed OTE and polycrystalline graphite. Multiwalled carbon nanotubes show low series resistance and low charge transfer resistance promising an improved fill factor (and efficiency) in DSSCs assembled with such materials as counter electrodes.

  16. Impedance Matched Absorptive Thermal Blocking Filters

    NASA Technical Reports Server (NTRS)

    Wollack, E. J.; Chuss, D. T.; Rostem, K.; U-Yen, K.

    2014-01-01

    We have designed, fabricated and characterized absorptive thermal blocking filters for cryogenic microwave applications. The transmission line filter's input characteristic impedance is designed to match 50O and its response has been validated from 0-to-50GHz. The observed return loss in the 0-to-20GHz design band is greater than 20 dB and shows graceful degradation with frequency. Design considerations and equations are provided that enable this approach to be scaled and modified for use in other applications.

  17. Impedance Matched Absorptive Thermal Blocking Filters

    NASA Technical Reports Server (NTRS)

    Wollack, E. J.; Chuss, D. T.; U-Yen, K.; Rostem, K.

    2014-01-01

    We have designed, fabricated and characterized absorptive thermal blocking filters for cryogenic microwave applications. The transmission line filter's input characteristic impedance is designed to match 50 Omega and its response has been validated from 0-to-50GHz. The observed return loss in the 0-to-20GHz design band is greater than 20 dB and shows graceful degradation with frequency. Design considerations and equations are provided that enable this approach to be scaled and modified for use in other applications.

  18. Measurement of shear impedances of viscoelastic fluids

    SciTech Connect

    Sheen, Shuh-Haw; Chien, Hual-Te; Raptis, A.C.

    1996-12-31

    Shear-wave reflection coefficients from a solid/fluid interface are derived for non-Newtonian fluids that can be described by Maxwell, Voigt, and power-law fluid models. Based on model calculations, we have identified the measurable effects on the reflection coefficients due to fluid non-Newtonian behavior. The models are used to interpret the viscosity data obtained by a technique based on shear impedance measurement.

  19. Application of impedance spectroscopy to SOFC research

    SciTech Connect

    Hsieh, G.; Mason, T.O.; Pederson, L.R.

    1996-12-31

    With the resurgence of interest in solid oxide fuel cells and other solid state electrochemical devices, techniques originally developed for characterizing aqueous systems are being adapted and applied to solid state systems. One of these techniques, three-electrode impedance spectroscopy, is particularly powerful as it allows characterization of subcomponent and interfacial properties. Obtaining accurate impedance spectra, however, is difficult as reference electrode impedance is usually non-negligible and solid electrolytes typically have much lower conductance than aqueous solutions. Faidi et al and Chechirlian et al have both identified problems associated with low conductivity media. Other sources of error are still being uncovered. Ford et al identified resistive contacts with large time constants as a possibility, while Me et al showed that the small contact capacitance of the reference electrode was at fault. Still others show that instrument limitations play a role. Using the voltage divider concept, a simplified model that demonstrates the interplay of these various factors, predicts the form of possible distortions, and offers means to minimize errors is presented.

  20. Bioelectrical impedance analysis of bovine milk fat

    NASA Astrophysics Data System (ADS)

    Veiga, E. A.; Bertemes-Filho, P.

    2012-12-01

    Three samples of 250ml at home temperature of 20°C were obtained from whole, low fat and fat free bovine UHT milk. They were analysed by measuring both impedance spectra and dc conductivity in order to establish the relationship between samples related to fat content. An impedance measuring system was developed, which is based on digital oscilloscope, a current source and a FPGA. Data was measured by the oscilloscope in the frequency 1 kHz to 100 kHz. It was showed that there is approximately 7.9% difference in the conductivity between whole and low fat milk whereas 15.9% between low fat and free fat one. The change of fatness in the milk can be significantly sensed by both impedance spectra measurements and dc conductivity. This result might be useful for detecting fat content of milk in a very simple way and also may help the development of sensors for measuring milk quality, as for example the detection of mastitis.

  1. On the directional symmetry of the impedance

    SciTech Connect

    Heifets, S.A.

    1990-03-01

    The independence of the impedance on the beam direction is an important feature of an accelerator structure, in particular, for the electron-positron storage rings where bunches of opposite charges travel through the same vacuum chamber in opposite directions. Recently Gluckstern and Zotter considered a cylindrically symmetric but longitudinally asymmetric cavity with side pipes of equal radii. They were able to prove that for a relativistic particle the longitudinal impedance of the cavity with an arbitrary shape is independent of the direction in which the beam travels through it. Their result corroborates numerical observations of the independence of the wakefield obtained with the code TBCI. Bisognano gave an elegant proof of the same statement. His approach is based on a reciprocity relation applied to the tensor Green's function. I follow here his idea in a somewhat simpler way to obtain more general and physically transparent proof of this property for both longitudinal and transverse impedances. The result is valid for a cavity with no azimuthal symmetry and for arbitrary particle velocity, as soon as it may be considered constant. At the same time the limits of its validity are shown.

  2. PEP-X IMPEDANCE AND INSTABILITY CALCULATIONS

    SciTech Connect

    Bane, K.L.F.; Lee, L.-Q.; Ng, C.; Stupakov, G.; au Wang, L.; Xiao, L.; /SLAC

    2010-08-25

    PEP-X, a next generation, ring-based light source is designed to run with beams of high current and low emittance. Important parameters are: energy 4.5 GeV, circumference 2.2 km, beam current 1.5 A, and horizontal and vertical emittances, 185 pm by 8 pm. In such a machine it is important that impedance driven instabilities not degrade the beam quality. In this report they study the strength of the impedance and its effects in PEP-X. For the present, lacking a detailed knowledge of the vacuum chamber shape, they create a straw man design comprising important vacuum chamber objects to be found in the ring, for which they then compute the wake functions. From the wake functions they generate an impedance budget and a pseudo-Green function wake representing the entire ring, which they, in turn, use for performing microwave instability calculations. In this report they, in addition, consider in PEP-X the transverse mode-coupling, multi-bunch transverse, and beam-ion instabilities.

  3. Imaging and characterizing root systems using electrical impedance tomography

    NASA Astrophysics Data System (ADS)

    Kemna, A.; Weigand, M.; Kelter, M.; Pfeifer, J.; Zimmermann, E.; Walter, A.

    2011-12-01

    Root architecture, growth, and activity play an essential role regarding the nutrient uptake of roots in soils. While in recent years advances could be achieved concerning the modeling of root systems, measurement methods capable of imaging, characterizing, and monitoring root structure and dynamics in a non-destructive manner are still lacking, in particular at the field scale. We here propose electrical impedance tomography (EIT) for the imaging of root systems. The approach takes advantage of the low-frequency capacitive electrical properties of the soil-root interface and the root tissue. These properties are based on the induced migration of ions in an externally applied electric field and give rise to characteristic impedance spectra which can be measured by means of electrical impedance spectroscopy. The latter technique was already successfully applied in the 10 Hz to 1 MHz range by Ozier-Lafontaine and Bajazet (2005) to monitor root growth of tomato. We here apply the method in the 1 mHz to 45 kHz range, requiring four-electrode measurements, and demonstrate its implementation and potential in an imaging framework. Images of real and imaginary components of complex electrical conductivity are computed using a finite-element based inversion algorithm with smoothness-constraint regularization. Results from laboratory measurements on rhizotrons with different root systems (barley, rape) show that images of imaginary conductivity delineate the spatial extent of the root system under investigation, while images of real conductivity show a less clear response. As confirmed by numerical simulations, the latter could be explained by the partly compensating electrical conduction properties of epidermis (resistive) and inner root cells (conductive), indicating the limitations of conventional electrical resistivity tomography. The captured spectral behavior exhibits two distinct relaxation processes with Cole-Cole type signatures, which we interpret as the responses

  4. Dynamic assessment of Amyloid oligomers - cell membrane interaction by advanced impedance spectroscopy

    NASA Astrophysics Data System (ADS)

    Gheorghiu, M.; David, S.; Polonschii, C.; Bratu, D.; Gheorghiu, E.

    2013-04-01

    The amyloid β (Aβ) peptides are believed to be pivotal in Alzheimer's disease (AD) pathogenesis and onset of vascular dysfunction. Recent studies indicate that Aβ1-42 treatment influences the expression of tight junction protein complexes, stress fibre formation, disruption and aggregation of actin filaments and cellular gap formation. Aiming for functional characterization of model cells upon Aβ1-42 treatment, we deployed an advanced Electric Cell-substrate Impedance Sensing for monitoring cell evolution. A precision Impedance Analyzer with a multiplexing module developed in house was used for recording individual electrode sets in the 40 Hz - 100 KHz frequency range. In a step forward from the classical ECIS assays, we report on a novel data analysis algorithm that enables access to cellular and paracellular electrical parameters and cell surface interaction with fully developed cell monolayers. The evolution of the impedance at selected frequencies provides evidence for a dual effect of Aβ42 exposure, at both paracellular permeability and cell adherence level, with intricate dynamics that open up new perspectives on Aβ1-42 oligomers - cell membrane interaction. Validation of electrical impedance assays of the amyloid fibrils effect on cell membrane structure is achieved by both AFM analysis and Surface Plasmon Resonance studies. The capabilities of this noninvasive, real time platform for cell analysis in a wider applicative context are outlined.

  5. A Chicken Tissue Phantom for Studying an Electrical Impedance Tomography (EIT) System Suitable for Clinical Imaging

    NASA Astrophysics Data System (ADS)

    Bera, Tushar Kanti; Nagaraju, J.

    2011-12-01

    The study of practical phantoms is essential for assessing the reconstruction algorithms and instrumentation used in Electrical Impedance Tomography (EIT). Responses of saline phantoms with insulator inhomogeneities differ from the real tissue phantoms in several aspects. Also, it is difficult to reconstruct the actual resistivity of the insulator inhomogeneity in a saline background because of their large resistivity difference. A practical biological phantom consisting of two different materials with low resistivity difference is more suitable for impedance imaging studies. In order to demonstrate this, a chicken tissue phantom was developed to study the resistivity imaging in EIT. A 16-electrode array was placed inside the phantom tank filled with chicken muscle tissue paste and chicken tissue. A 1 mA, 50 kHz sinusoidal current was injected at the phantom boundary and the boundary potentials are measured using opposite current injection protocol. Resistivity images were reconstructed from the boundary data using Electrical Impedance and Diffuse Optical Reconstruction Software (EIDORS) and the reconstruction was evaluated by calculating the contrast parameters of the images. Results show that the resistivity of the chicken fat is successfully reconstructed with a proper background resistivity. Impedance spectroscopic studies show that the chicken tissue phantom can be suitably used to evaluate a multifrequency EIT system.

  6. Dynamic Impedance Model of the Skin-Electrode Interface for Transcutaneous Electrical Stimulation

    PubMed Central

    Vargas Luna, José Luis; Krenn, Matthias; Cortés Ramírez, Jorge Armando; Mayr, Winfried

    2015-01-01

    Transcutaneous electrical stimulation can depolarize nerve or muscle cells applying impulses through electrodes attached on the skin. For these applications, the electrode-skin impedance is an important factor which influences effectiveness. Various models describe the interface using constant or current-depending resistive-capacitive equivalent circuit. Here, we develop a dynamic impedance model valid for a wide range stimulation intensities. The model considers electroporation and charge-dependent effects to describe the impedance variation, which allows to describe high-charge pulses. The parameters were adjusted based on rectangular, biphasic stimulation pulses generated by a stimulator, providing optionally current or voltage-controlled impulses, and applied through electrodes of different sizes. Both control methods deliver a different electrical field to the tissue, which is constant throughout the impulse duration for current-controlled mode or have a very current peak for voltage-controlled. The results show a predominant dependence in the current intensity in the case of both stimulation techniques that allows to keep a simple model. A verification simulation using the proposed dynamic model shows coefficient of determination of around 0.99 in both stimulation types. The presented method for fitting electrode-skin impedance can be simple extended to other stimulation waveforms and electrode configuration. Therefore, it can be embedded in optimization algorithms for designing electrical stimulation applications even for pulses with high charges and high current spikes. PMID:25942010

  7. Impedance monitoring at tendon-anchorage via mountable PZT interface and temperature-effect compensation

    NASA Astrophysics Data System (ADS)

    Huynh, Thanh-Canh; Nguyen, Tuan-Cuong; Choi, Sang-Hoon; Kim, Jeong-Tae

    2016-04-01

    In this study, the pre-stress force in pre-stressed concrete (PSC) girders is monitored via mountable PZT interface under varying temperature. Firstly, an impedance-based technique using mountable PZT interface is proposed for pre-stress-loss monitoring in tendon-anchorage systems. A cross correlation-based temperature-effect compensation algorithm using an effective frequency shift (EFS) of impedance signatures is visited. Secondly, lab-scale experiments are performed on a PSC girder instrumented with a mountable PZT interface at tendon-anchorage. A series of temperature variation and pre-stress-loss events are simulated for the lab-scale PSC girder. Thirdly, the feasibility of the mountable PZT interface for pre-stress-loss monitoring in tendon-anchorage is experimentally verified under constant temperature conditions. Finally, the PZT interface device is examined for pre-stress-loss monitoring under temperature changes to validate its applicability. The temperature effect on impedance signatures is compensated by minimizing cross-correlation deviation between impedance patterns of the mountable PZT interface.

  8. Pulse wave detection method based on the bio-impedance of the wrist.

    PubMed

    He, Jianman; Wang, Mengjun; Li, Xiaoxia; Li, Gang; Lin, Ling

    2016-05-01

    The real-time monitoring of pulse rate can evaluate the heart health to some extent, and the measurement of bio-impedance has the potential in wearable health monitoring system. In this paper, an effective method, which contains self-balancing bridge, flexible electrode, and high-speed digital lock-in algorithm (DLIA) with over-sampling, was designed to detect the impedance pulse wave at the wrist. By applying the self-balancing bridge, the basic impedance can be compensated as much as possible, and the low amplitude of impedance variation related to heart pulse can be obtained more easily. And the flexible conductive rubber electrode used in our experiment is human-friendly. Besides, the over-sampling method and high-speed DLIA are used to enhance the effective resolution of the existing data sampled by analog to digital converter. With the high-speed data process and simple circuit above, this proposed method has the potential in wrist-band wearable systems and it can satisfy quests of small volume and low power consumption. PMID:27250460

  9. Pulse wave detection method based on the bio-impedance of the wrist

    NASA Astrophysics Data System (ADS)

    He, Jianman; Wang, Mengjun; Li, Xiaoxia; Li, Gang; Lin, Ling

    2016-05-01

    The real-time monitoring of pulse rate can evaluate the heart health to some extent, and the measurement of bio-impedance has the potential in wearable health monitoring system. In this paper, an effective method, which contains self-balancing bridge, flexible electrode, and high-speed digital lock-in algorithm (DLIA) with over-sampling, was designed to detect the impedance pulse wave at the wrist. By applying the self-balancing bridge, the basic impedance can be compensated as much as possible, and the low amplitude of impedance variation related to heart pulse can be obtained more easily. And the flexible conductive rubber electrode used in our experiment is human-friendly. Besides, the over-sampling method and high-speed DLIA are used to enhance the effective resolution of the existing data sampled by analog to digital converter. With the high-speed data process and simple circuit above, this proposed method has the potential in wrist-band wearable systems and it can satisfy quests of small volume and low power consumption.

  10. Oblique impacts into low impedance layers

    NASA Astrophysics Data System (ADS)

    Stickle, A. M.; Schultz, P. H.

    2009-12-01

    Planetary impacts occur indiscriminately, in all locations and materials. Varied geologic settings can have significant effects on the impact process, including the coupling between the projectile and target, the final damage patterns and modes of deformation that occur. For example, marine impact craters are not identical to impacts directly into bedrock or into sedimentary materials, though many of the same fundamental processes occur. It is therefore important, especially when considering terrestrial impacts, to understand how a low impedance sedimentary layer over bedrock affects the deformation process during and after a hypervelocity impact. As a first step, detailed comparisons between impacts and hydrocode models were performed. Experiments performed at the NASA Ames Vertical Gun Range of oblique impacts into polymethylmethacrylate (PMMA) targets with low impedance layers were performed and compared to experiments of targets without low impedance layers, as well as to hydrocode models under identical conditions. Impact velocities ranged from 5 km/s to 5.6 km/s, with trajectories from 30 degrees to 90 degrees above the horizontal. High-speed imaging provided documentation of the sequence and location of failure due to impact, which was compared to theoretical models. Plasticine and ice were used to construct the low impedance layers. The combination of experiments and models reveals the modes of failure due to a hypervelocity impact. How such failure is manifested at large scales can present a challenge for hydrocodes. CTH models tend to overestimate the amount of damage occurring within the targets and have difficulties perfectly reproducing morphologies; nevertheless, they provide significant and useful information about the failure modes and style within the material. CTH models corresponding to the experiments allow interpretation of the underlying processes involved as well as provide a benchmark for the experimental analysis. The transparency of PMMA

  11. The Influence of Segmental Impedance Analysis in Predicting Validity of Consumer Grade Bioelectrical Impedance Analysis Devices

    NASA Astrophysics Data System (ADS)

    Sharp, Andy; Heath, Jennifer; Peterson, Janet

    2008-05-01

    Consumer grade bioelectric impedance analysis (BIA) instruments measure the body's impedance at 50 kHz, and yield a quick estimate of percent body fat. The frequency dependence of the impedance gives more information about the current pathway and the response of different tissues. This study explores the impedance response of human tissue at a range of frequencies from 0.2 - 102 kHz using a four probe method and probe locations standard for segmental BIA research of the arm. The data at 50 kHz, for a 21 year old healthy Caucasian male (resistance of 180φ±10 and reactance of 33φ±2) is in agreement with previously reported values [1]. The frequency dependence is not consistent with simple circuit models commonly used in evaluating BIA data, and repeatability of measurements is problematic. This research will contribute to a better understanding of the inherent difficulties in estimating body fat using consumer grade BIA devices. [1] Chumlea, William C., Richard N. Baumgartner, and Alex F. Roche. ``Specific resistivity used to estimate fat-free mass from segmental body measures of bioelectrical impedance.'' Am J Clin Nutr 48 (1998): 7-15.

  12. Impedance analysis of fibroblastic cell layers measured by electric cell-substrate impedance sensing

    NASA Astrophysics Data System (ADS)

    Lo, Chun-Min; Ferrier, Jack

    1998-06-01

    Impedance measurements of cell layers cultured on gold electrode surfaces obtained by electric cell-substrate impedance sensing provide morphological information such as junctional resistance and cell-substrate separation. Previously, a model that assumes that cells have a disklike shape and that electric currents flow radially underneath the ventral cell surface and then through the paracellular space has been used to theoretically calculate the impedance of the cell-covered electrode. In this paper we propose an extended model of impedance analysis for cell layers where cellular shape is rectangular. This is especially appropriate for normal fibroblasts in culture. To verify the model, we analyze impedance data obtained from four different kinds of fibroblasts that display a long rectangular shape. In addition, we measure the average cell-substrate separation of human gingival fibroblasts at different temperatures. At temperatures of 37, 22, and 4 °C, the average separation between ventral cell surface and substratum are 46, 55, and 89 nm, respectively.

  13. Label-Free Impedance Biosensors: Opportunities and Challenges

    PubMed Central

    Daniels, Jonathan S.; Pourmand, Nader

    2007-01-01

    Impedance biosensors are a class of electrical biosensors that show promise for point-of-care and other applications due to low cost, ease of miniaturization, and label-free operation. Unlabeled DNA and protein targets can be detected by monitoring changes in surface impedance when a target molecule binds to an immobilized probe. The affinity capture step leads to challenges shared by all label-free affinity biosensors; these challenges are discussed along with others unique to impedance readout. Various possible mechanisms for impedance change upon target binding are discussed. We critically summarize accomplishments of past label-free impedance biosensors and identify areas for future research. PMID:18176631

  14. Wakefield and impedance studies of a liner using MAFIA

    NASA Astrophysics Data System (ADS)

    Chou, W.; Barts, T.

    1993-12-01

    The liner is a perforated beam tube which is coaxial with an outer bore tube. The 3D code MAFIA version 3.1 is used to study the wakefields, impedances, and resonances of this structure. The short range wakes and low frequency (below the cutoff) impedances are in agreement with the theoretical model. The long range wakes and high frequency resonances are associated with the distribution of the holes (or slots). The dependence of the impedance on the size, shape, and pattern of the holes (or slots) is studied. The impact of the liner impedance on the SSC impedance budget is discussed.

  15. Closed-loop identification: application to the estimation of limb impedance in a compliant environment.

    PubMed

    Westwick, David T; Perreault, Eric J

    2011-03-01

    The force and position data used to construct models of limb impedance are often obtained from closed-loop experiments. If the system is tested in a stiff environment, it is possible to treat the data as if they were obtained in open loop. However, when limb impedance is studied in a compliant environment, the presence of feedback cannot be ignored. While unbiased estimates of a system can be obtained directly using the prediction error method, the same cannot be said when linear regression or correlation analysis is used to fit nonparametric time- or frequency-domain models. We develop a prediction error minimization-based identification method for a nonparametric time-domain model augmented with a parametric noise model. The identification algorithm is tested on a dynamic mass-spring-damper system and returns consistent estimates of the system's properties under both stiff and compliant feedback control. The algorithm is then used to estimate the impedance of a human elbow joint in both stiff and compliant environments. PMID:21134808

  16. Quantum algorithms

    NASA Astrophysics Data System (ADS)

    Abrams, Daniel S.

    This thesis describes several new quantum algorithms. These include a polynomial time algorithm that uses a quantum fast Fourier transform to find eigenvalues and eigenvectors of a Hamiltonian operator, and that can be applied in cases (commonly found in ab initio physics and chemistry problems) for which all known classical algorithms require exponential time. Fast algorithms for simulating many body Fermi systems are also provided in both first and second quantized descriptions. An efficient quantum algorithm for anti-symmetrization is given as well as a detailed discussion of a simulation of the Hubbard model. In addition, quantum algorithms that calculate numerical integrals and various characteristics of stochastic processes are described. Two techniques are given, both of which obtain an exponential speed increase in comparison to the fastest known classical deterministic algorithms and a quadratic speed increase in comparison to classical Monte Carlo (probabilistic) methods. I derive a simpler and slightly faster version of Grover's mean algorithm, show how to apply quantum counting to the problem, develop some variations of these algorithms, and show how both (apparently distinct) approaches can be understood from the same unified framework. Finally, the relationship between physics and computation is explored in some more depth, and it is shown that computational complexity theory depends very sensitively on physical laws. In particular, it is shown that nonlinear quantum mechanics allows for the polynomial time solution of NP-complete and #P oracle problems. Using the Weinberg model as a simple example, the explicit construction of the necessary gates is derived from the underlying physics. Nonlinear quantum algorithms are also presented using Polchinski type nonlinearities which do not allow for superluminal communication. (Copies available exclusively from MIT Libraries, Rm. 14- 0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

  17. Superconducting fault current-limiter with variable shunt impedance

    DOEpatents

    Llambes, Juan Carlos H; Xiong, Xuming

    2013-11-19

    A superconducting fault current-limiter is provided, including a superconducting element configured to resistively or inductively limit a fault current, and one or more variable-impedance shunts electrically coupled in parallel with the superconducting element. The variable-impedance shunt(s) is configured to present a first impedance during a superconducting state of the superconducting element and a second impedance during a normal resistive state of the superconducting element. The superconducting element transitions from the superconducting state to the normal resistive state responsive to the fault current, and responsive thereto, the variable-impedance shunt(s) transitions from the first to the second impedance. The second impedance of the variable-impedance shunt(s) is a lower impedance than the first impedance, which facilitates current flow through the variable-impedance shunt(s) during a recovery transition of the superconducting element from the normal resistive state to the superconducting state, and thus, facilitates recovery of the superconducting element under load.

  18. Bioelectrical Impedance Methods for Noninvasive Health Monitoring: A Review

    PubMed Central

    Bera, Tushar Kanti

    2014-01-01

    Under the alternating electrical excitation, biological tissues produce a complex electrical impedance which depends on tissue composition, structures, health status, and applied signal frequency, and hence the bioelectrical impedance methods can be utilized for noninvasive tissue characterization. As the impedance responses of these tissue parameters vary with frequencies of the applied signal, the impedance analysis conducted over a wide frequency band provides more information about the tissue interiors which help us to better understand the biological tissues anatomy, physiology, and pathology. Over past few decades, a number of impedance based noninvasive tissue characterization techniques such as bioelectrical impedance analysis (BIA), electrical impedance spectroscopy (EIS), electrical impedance plethysmography (IPG), impedance cardiography (ICG), and electrical impedance tomography (EIT) have been proposed and a lot of research works have been conducted on these methods for noninvasive tissue characterization and disease diagnosis. In this paper BIA, EIS, IPG, ICG, and EIT techniques and their applications in different fields have been reviewed and technical perspective of these impedance methods has been presented. The working principles, applications, merits, and demerits of these methods has been discussed in detail along with their other technical issues followed by present status and future trends. PMID:27006932

  19. Mechanism of the formation for thoracic impedance change.

    PubMed

    Kuang, Ming-Xing; Xiao, Qiu-Jin; Cui, Chao-Ying; Kuang, Nan-Zhen; Hong, Wen-Qin; Hu, Ai-Rong

    2010-03-01

    The purpose of this study is to investigate the mechanism of the formation for thoracic impedance change. On the basis of Ohm's law and the electrical field distribution in the cylindrical volume conductor, the formula about the thoracic impedance change are deduced, and they are demonstrated with the model experiment. The results indicate that the thoracic impedance change caused by single blood vessel is directly proportional to the ratio of the impedance change to the basal impedance of the blood vessel itself, to the length of the blood vessel appearing between the current electrodes, and to the basal impedance between two detective electrodes on the chest surface, while it is inversely proportional to the distance between the blood vessel and the line joining two detective electrodes. The thoracic impedance change caused by multiple blood vessels together is equal to the algebraic addition of all thoracic impedance changes resulting from the individual blood vessels. That is, the impedance changes obey the principle of adding scalars in the measurement of the electrical impedance graph. The present study can offer the theoretical basis for the waveform reconstruction of Impedance cardiography (ICG). PMID:20336823

  20. Characterization of protein-immobilized polystyrene nanoparticles using impedance spectroscopy.

    PubMed

    Park, Soo-In; Lee, Sang-Yup

    2014-10-01

    A novel approach for characterization of non-conductive protein-immobilized nanoparticles using AC impedance spectroscopy combined with conductive atomic force microscopy was examined. As AC impedance spectroscopy can provide information on diverse electrical properties such as capacitance and inductance, it is applicable to the characterization of non-conductive substances. Several non-conductive protein-immobilized polystyrene nanoparticles were analyzed using AC impedance spectroscopy, and their impedance spectra were used as markers for nanoparticle identification. Analyses of impedance signals using an electrical circuit model established that the capacitance and inductance of each nanoparticle changed with the adsorbed protein and that impedance spectral differences were characteristic properties of the proteins. From this study, AC impedance spectroscopy was shown to be a useful tool for characterization of non-conductive nanoparticles and is expected to be applicable to the development of sensors for nanomaterials. PMID:25942903

  1. Impedance Noise Identification for State-of-Health Prognostics

    SciTech Connect

    Jon P. Christophersen; Chester G. Motloch; John L. Morrison; Ian B. Donnellan; William H. Morrison

    2008-07-01

    Impedance Noise Identification is an in-situ method of measuring battery impedance as a function of frequency using a random small signal noise excitation source. Through a series of auto- and cross-correlations and Fast Fourier Transforms, the battery complex impedance as a function of frequency can be determined. The results are similar to those measured under a lab-scale electrochemical impedance spectroscopy measurement. The lab-scale measurements have been shown to correlate well with resistance and power data that are typically used to ascertain the remaining life of a battery. To this end, the Impedance Noise Identification system is designed to acquire the same type of data as an on-board tool. A prototype system is now under development, and results are being compared to standardized measurement techniques such as electrochemical impedance spectroscopy. A brief description of the Impedance Noise Identification hardware system and representative test results are presented.

  2. A review of impedance measurements of whole cells.

    PubMed

    Xu, Youchun; Xie, Xinwu; Duan, Yong; Wang, Lei; Cheng, Zhen; Cheng, Jing

    2016-03-15

    Impedance measurement of live biological cells is widely accepted as a label free, non-invasive and quantitative analytical method to assess cell status. This method is easy-to-use and flexible for device design and fabrication. In this review, three typical techniques for impedance measurement, i.e., electric cell-substrate impedance sensing, Impedance flow cytometry and electric impedance spectroscopy, are reviewed from the aspects of theory, to electrode design and fabrication, and applications. Benefiting from the integration of microelectronic and microfluidic techniques, impedance sensing methods have expanded their applications to nearly all aspects of biology, including living cell counting and analysis, cell biology research, cancer research, drug screening, and food and environmental safety monitoring. The integration with other techniques, the fabrication of devices for certain biological assays, and the development of point-of-need diagnosis devices is predicted to be future trend for impedance sensing techniques. PMID:26513290

  3. Haplotyping algorithms

    SciTech Connect

    Sobel, E.; Lange, K.; O`Connell, J.R.

    1996-12-31

    Haplotyping is the logical process of inferring gene flow in a pedigree based on phenotyping results at a small number of genetic loci. This paper formalizes the haplotyping problem and suggests four algorithms for haplotype reconstruction. These algorithms range from exhaustive enumeration of all haplotype vectors to combinatorial optimization by simulated annealing. Application of the algorithms to published genetic analyses shows that manual haplotyping is often erroneous. Haplotyping is employed in screening pedigrees for phenotyping errors and in positional cloning of disease genes from conserved haplotypes in population isolates. 26 refs., 6 figs., 3 tabs.

  4. Voltage Based Detection Method for High Impedance Fault in a Distribution System

    NASA Astrophysics Data System (ADS)

    Thomas, Mini Shaji; Bhaskar, Namrata; Prakash, Anupama

    2015-06-01

    High-impedance faults (HIFs) on distribution feeders cannot be detected by conventional protection schemes, as HIFs are characterized by their low fault current level and waveform distortion due to the nonlinearity of the ground return path. This paper proposes a method to identify the HIFs in distribution system and isolate the faulty section, to reduce downtime. This method is based on voltage measurements along the distribution feeder and utilizes the sequence components of the voltages. Three models of high impedance faults have been considered and source side and load side breaking of the conductor have been studied in this work to capture a wide range of scenarios. The effect of neutral grounding of the source side transformer is also accounted in this study. The results show that the algorithm detects the HIFs accurately and rapidly. Thus, the faulty section can be isolated and service can be restored to the rest of the consumers.

  5. Noninvasive Imaging of Head-Brain Conductivity Profiles Using Magnetic Resonance Electrical Impedance Imaging

    PubMed Central

    Zhang, Xiaotong; Yan, Dandan; Zhu, Shanan; He, Bin

    2008-01-01

    Magnetic resonance electrical impedance tomography (MREIT) is a recently introduced non-invasive conductivity imaging modality, which combines the magnetic resonance current density imaging (CDI) and the traditional electrical impedance tomography (EIT) techniques. MREIT is aimed at providing high spatial resolution images of electrical conductivity, by avoiding solving the well-known ill-posed problem in the traditional EIT. In this paper, we review our research activities in MREIT imaging of head-brain tissue conductivity profiles. We have developed several imaging algorithms and conducted a series of computer simulations for MREIT imaging of the head and brain tissues. Our work suggests MREIT brain imaging may become a useful tool in imaging conductivity distributions of the brain and head. PMID:18799394

  6. Determination of in vivo mechanical properties of long bones from their impedance response curves

    NASA Technical Reports Server (NTRS)

    Borders, S. G.

    1981-01-01

    A mathematical model consisting of a uniform, linear, visco-elastic, Euler-Bernoulli beam to represent the ulna or tibia of the vibrating forearm or leg system is developed. The skin and tissue compressed between the probe and bone is represented by a spring in series with the beam. The remaining skin and tissue surrounding the bone is represented by a visco-elastic foundation with mass. An extensive parametric study is carried out to determine the effect of each parameter of the mathematical model on its impedance response. A system identification algorithm is developed and programmed on a digital computer to determine the parametric values of the model which best simulate the data obtained from an impedance test.

  7. Techniques for beam impedance measurements above cutoff

    SciTech Connect

    Lambertson, G.R.; Jacob, A.F.; Rimmer, R.A.; Voelker, F.

    1990-08-01

    Methods for measuring beam impedance above cutoff have been very limited. For design work on the ALS we have developed two techniques that yield data in the frequency domain with high sensitivity. The first is an extension of the wire method; the second utilizes traveling TM waves to simulate the beam's fields at the wall, and thus avoids the mechanical difficulties of mounting the wire. It is also more sensitive than the other method but the interpretation is complicated by the presence of higher order modes. With either method we were able to detect resonant peaks smaller than 1 Ohm at 10 GHz.

  8. Method for conducting nonlinear electrochemical impedance spectroscopy

    DOEpatents

    Adler, Stuart B.; Wilson, Jamie R.; Huff, Shawn L.; Schwartz, Daniel T.

    2015-06-02

    A method for conducting nonlinear electrochemical impedance spectroscopy. The method includes quantifying the nonlinear response of an electrochemical system by measuring higher-order current or voltage harmonics generated by moderate-amplitude sinusoidal current or voltage perturbations. The method involves acquisition of the response signal followed by time apodization and fast Fourier transformation of the data into the frequency domain, where the magnitude and phase of each harmonic signal can be readily quantified. The method can be implemented on a computer as a software program.

  9. Bioelectrical impedance assessment of wound healing.

    PubMed

    Lukaski, Henry C; Moore, Micheal

    2012-01-01

    Objective assessment of wound healing is fundamental to evaluate therapeutic and nutritional interventions and to identify complications. Despite availability of many techniques to monitor wounds, there is a need for a safe, practical, accurate, and effective method. A new method is localized bioelectrical impedance analysis (BIA) that noninvasively provides information describing cellular changes that occur during healing and signal complications to wound healing. This article describes the theory and application of localized BIA and provides examples of its use among patients with lower leg wounds. This promising method may afford clinicians a novel technique for routine monitoring of interventions and surveillance of wounds. PMID:22401341

  10. Broadband Planar 5:1 Impedence Transformer

    NASA Technical Reports Server (NTRS)

    Ehsan, Negar; Hsieh, Wen-Ting; Moseley, Samuel H.; Wollack, Edward J.

    2015-01-01

    This paper presents a broadband Guanella-type planar impedance transformer that transforms so 50 omega to 10 omega with a 10 dB bandwidth of 1-14GHz. The transformer is designed on a flexible 50 micrometer thick polyimide substrate in microstrip and parallel-plate transmission line topologies, and is Inspired by the traditional 4:1 Guanella transformer. Back-to-back transformers were designed and fabricated for characterization in a 50 omega system. Simulated and measured results are in excellent agreement.

  11. Sensitivity of PZT Impedance Sensors for Damage Detection of Concrete Structures

    PubMed Central

    Yang, Yaowen; Hu, Yuhang; Lu, Yong

    2008-01-01

    Piezoelectric ceramic Lead Zirconate Titanate (PZT) based electro-mechanical impedance (EMI) technique for structural health monitoring (SHM) has been successfully applied to various engineering systems. However, fundamental research work on the sensitivity of the PZT impedance sensors for damage detection is still in need. In the traditional EMI method, the PZT electro-mechanical (EM) admittance (inverse of the impedance) is used as damage indicator, which is difficult to specify the effect of damage on structural properties. This paper uses the structural mechanical impedance (SMI) extracted from the PZT EM admittance signature as the damage indicator. A comparison study on the sensitivity of the EM admittance and the structural mechanical impedance to the damages in a concrete structure is conducted. Results show that the SMI is more sensitive to the damage than the EM admittance thus a better indicator for damage detection. Furthermore, this paper proposes a dynamic system consisting of a number of single-degree-of-freedom elements with mass, spring and damper components to model the SMI. A genetic algorithm is employed to search for the optimal value of the unknown parameters in the dynamic system. An experiment is carried out on a two-storey concrete frame subjected to base vibrations that simulate earthquake. A number of PZT sensors are regularly arrayed and bonded to the frame structure to acquire PZT EM admittance signatures. The relationship between the damage index and the distance of the PZT sensor from the damage is studied. Consequently, the sensitivity of the PZT sensors is discussed and their sensing region in concrete is derived.

  12. Electrochemical impedance spectroscopy investigations of a microelectrode behavior in a thin-layer cell: Experimental and theoretical studies.

    PubMed

    Gabrielli, C; Keddam, M; Portail, N; Rousseau, P; Takenouti, H; Vivier, V

    2006-10-19

    Electrochemical impedance spectroscopy experiments were performed on a microdisk electrode in a thin-layer cell using a scanning electrochemical microscope for controlling the cell geometry. Experimental data showed that when the thin-layer thickness diminished, an additional low-frequency response appeared. It was ascribed to the radial diffusion of the electroactive species and was strongly dependent on the thin-layer dimensions (both thickness and diameter). Moreover, the numerical simulation of the impedance diagrams by finite element method calculations confirmed this behavior. An equivalent circuit based on a Randles-type circuit was proposed. Thus, the diffusion was described by introducing two electrical elements: one for the spherical diffusion and the other for the radial contribution. A nonlinear Simplex algorithm was used, and this circuit was shown to fit the impedance diagrams with a good accuracy. PMID:17034233

  13. Electrochemical Impedance Spectroscopy of Conductive Polymer Coatings

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; MacDowell, Louis G.

    1996-01-01

    Electrochemical impedance spectroscopy (EIS) was used to investigate the corrosion protection performance of twenty nine proprietary conductive polymer coatings for cold rolled steel under immersion in 3.55 percent NaCl. Corrosion potential as well as Bode plots of the data were obtained for each coating after one hour immersion, All coatings, with the exception of one, have a corrosion potential that is higher in the positive direction than the corrosion potential of bare steel under the same conditions. Group A consisted of twenty one coatings with Bode plots indicative of the capacitive behavior characteristic of barrier coatings. An equivalent circuit consisting of a capacitor in series with a resistor simulated the experimental EIS data for these coatings very well. Group B consisted of eight coatings that exhibited EIS spectra showing an inflection point which indicates that two time constants are present. This may be caused by an electrochemical process taking place which could be indicitive of coating failing. These coatings have a lower impedance that those in Group A.

  14. A high frequency electromagnetic impedance imaging system

    SciTech Connect

    Tseng, Hung-Wen; Lee, Ki Ha; Becker, Alex

    2003-01-15

    Non-invasive, high resolution geophysical mapping of the shallow subsurface is necessary for delineation of buried hazardous wastes, detecting unexploded ordinance, verifying and monitoring of containment or moisture contents, and other environmental applications. Electromagnetic (EM) techniques can be used for this purpose since electrical conductivity and dielectric permittivity are representative of the subsurface media. Measurements in the EM frequency band between 1 and 100 MHz are very important for such applications, because the induction number of many targets is small and the ability to determine the subsurface distribution of both electrical properties is required. Earlier workers were successful in developing systems for detecting anomalous areas, but quantitative interpretation of the data was difficult. Accurate measurements are necessary, but difficult to achieve for high-resolution imaging of the subsurface. We are developing a broadband non-invasive method for accurately mapping the electrical conductivity and dielectric permittivity of the shallow subsurface using an EM impedance approach similar to the MT exploration technique. Electric and magnetic sensors were tested to ensure that stray EM scattering is minimized and the quality of the data collected with the high-frequency impedance (HFI) system is good enough to allow high-resolution, multi-dimensional imaging of hidden targets. Additional efforts are being made to modify and further develop existing sensors and transmitters to improve the imaging capability and data acquisition efficiency.

  15. Method of Adjusting Acoustic Impedances for Impedance-Tunable Acoustic Segments

    NASA Technical Reports Server (NTRS)

    Jones, Kennie H (Inventor); Nark, Douglas M. (Inventor); Jones, Michael G. (Inventor); Parrott, Tony L. (Inventor); Lodding, Kenneth N. (Inventor)

    2012-01-01

    A method is provided for making localized decisions and taking localized actions to achieve a global solution. In an embodiment of the present invention, acoustic impedances for impedance-tunable acoustic segments are adjusted. A first acoustic segment through an N-th acoustic segment are defined. To start the process, the first acoustic segment is designated as a leader and a noise-reducing impedance is determined therefor. This is accomplished using (i) one or more metrics associated with the acoustic wave at the leader, and (ii) the metric(s) associated with the acoustic wave at the N-th acoustic segment. The leader, the N-th acoustic segment, and each of the acoustic segments exclusive of the leader and the N-th acoustic segment, are tuned to the noise-reducing impedance. The current leader is then excluded from subsequent processing steps. The designation of leader is then given one of the remaining acoustic segments, and the process is repeated for each of the acoustic segments through an (N-1)-th one of the acoustic segments.

  16. Plasma Impedance Spectrum Analyzer (PISA): an advanced impedance probe for measuring plasma density and other parameters

    NASA Astrophysics Data System (ADS)

    Rowland, D. E.; Pfaff, R. F.; Uribe, P.; Burchill, J.

    2006-12-01

    High-accuracy, high-cadence measurements of ionospheric electron density between 100 and a few x 106 / cc and electron temperature from 200 K to a few thousand K are of critical importance for understanding conductivity, Joule heating rates, and instability growth rates. We present results from the development of an impedance probe at NASA GSFC and show its strengths relative to other measurement techniques. Complementary measurement techniques such as Langmuir Probes, while providing extremely high measurement cadence, suffer from uncertainties in calibration, surface contamination effects, and wake/sheath effects. Impedance Probes function by measuring the phase shift between the voltage on a long antenna and the current flowing from the antenna into the plasma as a function of frequency. At frequencies for which the phase shift is zero, a plasma resonance is assumed to exist. These resonances depend on a variety of plasma parameters, including the electron density, electron temperature, and magnetic field strength, as well as the antenna geometry, angle between the antenna and the magnetic field, and sheath / Debye length effects, but do not depend on the surface properties of the antenna. Previous impedance probe designs which "lock" onto the upper hybrid resonance are susceptible to losing lock in low-density environments. Information about other resonances, including the series resonance (which strongly depends on temperature) and other resonances which may occur near the upper hybrid, confounding its identification, are typically not transmitted. The novel features of the GSFC Impedance Probe (PISA) include: 1) A white noise generator that stimulates a wide range of frequencies simultaneously, allowing the instrument to send down the entire impedance frequency spectrum every few milliseconds. This allows identification of all resonance frequencies, including the series resonance which depends on temperature. 2) DC bias voltage stepping to bring the antenna

  17. Algorithm for ventricular capture verification based on the mechanical evoked response.

    PubMed

    Yaacoby, E; Akselrod, S; Eldar, M; Glikson, M

    2005-07-01

    Automatic pacemaker capture verification is important for maintaining safety and low energy consumption in pacemaker patients. A new algorithm was developed, based on impedance measurement between pacing electrode poles, which reflects the distribution of the conducting medium between the poles and changes with effective contraction. Data acquired during pacemaker implant in 17 subjects were analysed, with intracardiac impedance recorded while pacing was performed in the ventricle at varying energies, resulting in multiple-captured and non-captured beats. The impedance signals of all captured/non-captured beats were analysed using three different algorithms, based on the morphology of the impedance signal. The algorithm decision for each beat was compared with an actual capture or non-capture, as determined from the simultaneous recording of surface ECG. Two of the three algorithms (Z1 and Zn) were based on impedance values, and one (Z'n) was based on the first derivative of the impedance. Z1 was based on a single sample, whereas Z'n and Z'n were based on several samples in each beat. The total accuracy for each was Z1: 43%, Zn: 87%, Z'n: 92%. It was concluded that impedance-based capture verification is feasible, that a multiple rather than single sample approach for signal classification is both feasible and superior, and that first derivative analysis with multiple samples (Z'n) provides the best results. PMID:16255434

  18. Three-dimensional inversion of magnetotelluric impedance tensor data and full distortion matrix

    NASA Astrophysics Data System (ADS)

    Avdeeva, A.; Moorkamp, M.; Avdeev, D.; Jegen, M.; Miensopust, M.

    2015-07-01

    Galvanic distortion of magnetotelluric (MT) data due to small-scale surficial bodies or due to topography is one of the major factors that prevents accurate imaging of the subsurface. We present a 3-D algorithm for joint inversion of MT impedance tensor data and a frequency-independent full distortion matrix that circumvents this problem. We perform several tests of our algorithm on synthetic data affected by different amounts of distortion. These tests show that joint inversion leads to a better conductivity model compared to the inversion of the MT impedance tensor without any correction for distortion effects. For highly distorted data, inversion without any distortion correction results in strong artefacts and we cannot fit the data to the specified noise level. When the distortion is reduced, we can fit the data to an RMS of one, but still observe artefacts in the shallow part of the model. In contrast, in both cases our joint inversion can fit the data within the assumed noise level and the resulting models are comparable to the inversion of undistorted data. In addition, we show that the elements of the full distortion matrix can be well resolved by our algorithm. Finally, when inverting undistorted data, including the distortion matrix in the inversion only results in a minor loss of resolution. We therefore consider our new approach a promising tool for the general analysis of field MT data.

  19. Impedance measurements of the Spallation Neutron Source extraction kicker system

    NASA Astrophysics Data System (ADS)

    Hahn, H.

    2004-10-01

    Transverse coupling impedance measurements of the Spallation Neutron Source (SNS) beam extraction system were performed and the results are here reported. The SNS beam extraction system is composed from 14 subsystems, each of which consists of a vertical kicker magnet plus a pulse forming network (PFN). Impedance bench measurements were performed on one large and one small aperture magnet, stand-alone as well as assembled with the first-article production PFN. The impedance measuring methods to cover the interesting frequency range from below 1 to 100MHz are described in considerable detail. The upper frequency range is properly covered by the conventional twin-wire method but it had to be supplemented at the low-frequency end by a direct input impedance measurement at the magnet busbar. Required modifications of the PFN to maintain the impedance budget are discussed. The total impedance estimate was finally obtained by quadratic scaling with vertical aperture from the two tested kicker subsystems.

  20. Transverse beam coupling impedance of the CERN Proton Synchrotron

    NASA Astrophysics Data System (ADS)

    Persichelli, S.; Migliorati, M.; Biancacci, N.; Gilardoni, S.; Metral, E.; Salvant, B.

    2016-04-01

    Beam coupling impedance is a fundamental parameter to characterize the electromagnetic interaction of a particle beam with the surrounding environment. Synchrotron machine performances are critically affected by instabilities and collective effects triggered by beam coupling impedance. In particular, transverse beam coupling impedance is expected to impact beam dynamics of the CERN Proton Synchrotron (PS), since a significant increase in beam intensity is foreseen within the framework of the LHC Injectors Upgrade (LIU) project. In this paper we describe the study of the transverse beam coupling impedance of the PS, taking into account the main sources of geometrical impedance and the contribution of indirect space charge at different energies. The total machine impedance budget, determined from beam-based dedicated machine measurement sessions, is also discussed and compared with the theoretical model.

  1. Impedance analysis of the PEP-II vacuum chamber

    SciTech Connect

    Ng, C.K.; Weiland, T.

    1995-05-01

    The PEP-II high energy ring (HER) vacuum chamber consists of a copper tube with periodically spaced pumping slots. The impedance of the vacuum chamber due to the slots is analyzed. Both narrow-band and broadband impedances are considered as well as longitudinal and transverse components thereof. It is found that although the broad-band impedance is tolerable, the narrow-band impedance may exceed the instability limit given by the natural damping with no feedback system on. Traveling wave modes in the chamber are the major source of this high value narrow-band impedance. We also study the dependences of the impedance on the slot length and the geometrical cross section.

  2. Electrical impedance tomography: so close to touching the holy grail

    PubMed Central

    2014-01-01

    Electrical impedance tomography is a new technology giving us lung imaging that may allow lung function to be monitored at the bedside. Several applications have been studied to guide mechanical ventilation at the bedside with electrical impedance tomography. Positive end-expiratory pressure trials guided by electrical impedance tomography are relevant in terms of recruited volume or homogeneity of the lung. Tidal impedance variation is a new parameter of electrical impedance tomography that may help physicians with ventilator settings in acute respiratory distress syndrome patients. This parameter is able to identify the onset of overdistention in the nondependent part and recruitment in the dependent part. Electrical impedance tomography presents a big step forward in mechanical ventilation. PMID:25041593

  3. Validation of a Numerical Method for Determining Liner Impedance

    NASA Technical Reports Server (NTRS)

    Watson, Willie R.; Jones, Michael G.; Tanner, Sharon E.; Parrott, Tony L.

    1996-01-01

    This paper reports the initial results of a test series to evaluate a method for determining the normal incidence impedance of a locally reacting acoustically absorbing liner, located on the lower wall of a duct in a grazing incidence, multi-modal, non-progressive acoustic wave environment without flow. This initial evaluation is accomplished by testing the methods' ability to converge to the known normal incidence impedance of a solid steel plate, and to the normal incidence impedance of an absorbing test specimen whose impedance was measured in a conventional normal incidence tube. The method is shown to converge to the normal incident impedance values and thus to be an adequate tool for determining the impedance of specimens in a grazing incidence, multi-modal, nonprogressive acoustic wave environment for a broad range of source frequencies.

  4. Transverse impedance measurement in RHIC and the AGS

    SciTech Connect

    Biancacci, Nicolo; Blaskiewicz, M.; Dutheil, Y.; Liu, C.; Mernick, M.; Minty, M.; White, S. M.

    2014-05-12

    The RHIC luminosity upgrade program aims for an increase of the polarized proton luminosity by a factor 2. To achieve this goal a significant increase in the beam intensity is foreseen. The beam coupling impedance could therefore represent a source of detrimental effects for beam quality and stability at high bunch intensities. For this reason it is essential to quantify the accelerator impedance budget and the major impedance sources, and possibly cure them. In this MD note we summarize the results of the 2013 transverse impedance measurements in the AGS and RHIC. The studies have been performed measuring the tune shift as a function of bunch intensity and deriving the total accelerator machine transverse impedance. For RHIC, we could obtain first promising results of impedance localization measurements as well.

  5. A comparison framework for temporal image reconstructions in electrical impedance tomography.

    PubMed

    Gagnon, Hervé; Grychtol, Bartłomiej; Adler, Andy

    2015-06-01

    Electrical impedance tomography (EIT) provides low-resolution images of internal conductivity distributions, but is able to achieve relatively high temporal resolutions. Most EIT image reconstruction algorithms do not explicitly account for the temporal constraints on the measurements or physiological processes under investigation. Instead, algorithms typically assume both that the conductivity distribution does not change during the acquisition of each EIT data frame, and that frames can be reconstructed independently, without consideration of the correlation between images. A failure to account for these temporal effects will result in aliasing-related artefacts in images. Several methods have been proposed to compensate for these effects, including interpolation of raw data, and reconstruction algorithms using Kalman and temporal filtering. However, no systematic work has been performed to understand the severity of the temporal artefacts nor the extent to which algorithms can account for them. We seek to address this need by developing a temporal comparison framework and figures of merit to assess the ability of reconstruction algorithms to account for temporal effects. Using this approach, we compare combinations of three reconstruction algorithms using three EIT data frame types: perfect, realistic and interpolated. The results show that, without accounting for temporal effects, artefacts are present in images for dynamic conductivity contrasts at frequencies 10-20 times slower than the frame rate. The proposed methods show some improvements in reducing these artefacts. PMID:26006181

  6. Impedance Matched to Vacuum, Invisible Edge, Diffraction Suppressed Mirror

    NASA Technical Reports Server (NTRS)

    Hagopian, John G. (Inventor); Roman, Patrick A. (Inventor); Shiri, Sharham (Inventor); Wollack, Edward J. (Inventor)

    2015-01-01

    Diffraction suppressed mirrors having an invisible edge are disclosed for incident light at both targeted wavelengths and broadband incident light. The mirrors have a first having at least one discontiguous portion having a plurality of nanostructured apertures. The discontiguous mirror portion impedance matches a relatively high impedance portion of the mirror to a relatively low impedance portion of the mirror, thereby reducing the diffraction edge effect otherwise present in a conventional mirror.

  7. Mutual impedance of nonplanar-skew sinusoidal dipoles

    NASA Technical Reports Server (NTRS)

    Richmond, J. H.; Geary, N. H.

    1975-01-01

    The mutual impedance expressions for parallel dipoles in terms of sine-integrals and cosine-integrals have been published by King (1957). The investigation reported provides analogous expressions for nonparallel dipoles. The expressions presented are most useful when the monopoles are close together. The theory of moment methods shows an approach for employing the mutual impedance of filamentary sinusoidal dipoles to calculate the impedance and scattering properties of straight and bent wires with small but finite diameter.

  8. Mutual impedance of nonplanar-skew sinusoidal dipoles

    NASA Technical Reports Server (NTRS)

    Richmond, J. H.; Geary, N. H.

    1974-01-01

    The mutual impedance of nonplanar-skew sinusoidal dipoles is presented as a summation of several exponential integrals with complex arguments. Mathematical models are developed to show the near-zone field of the sinusoidal dipole. The mutual impedance of coupled dipoles is expressed as the sum of four monopole-mobopole impedances to simplify the analysis procedure. The subroutines for solving the parameters of the dipoles are discussed.

  9. In vivo impedance evaluation of Au/PI microelectrode with surface modulated by alkanethiolate self-assembled monolayers.

    PubMed

    Lin, Hwa-Li; Lin, Chou-Ching K; Ju, Ming-Shaung; Liao, Jiunn-Der

    2011-02-01

    The goal of this study was to verify that a fully implanted microelectrode with modulated surface may have a reduced rising rate of total impedance and a longer life time. In the previous work, alkanethiolate self-assembled monolayers (SAMs) surface as protein-resistant spacer or cell-repulsive dense-packed spacer has been verified from in vitro experiments. In this study, microelectrodes with the same surface modulation were implanted into the subcutaneous layers of Wistar rats. Nine rats were implanted with the microelectrodes and the total impedance data were measured every 24 h for 2 weeks after implantation. An equivalent electrical circuit model of the electrode-tissue interface was established and parameters were estimated by using an optimization algorithm. Four out of nine rats had manifested acute inflammation reaction and the rests revealed only slight tissue response. Histological examination for the inflammatory group showed fibroblasts, macrophages, and polymorphonuclear leukocytes in adjacent to the electrode contact surface. In the inflammatory group, no significantly difference in total impedance was found in both types of electrodes. However, the trend of total impedance of SAMs-treated electrodes could maintain a steady state value after 1 week. For the non-inflammatory group, both types of electrodes could reduce the impedance value within implanted days. The tissue resistance might be related to the thickness of cells adhered upon the electrode contacts. PMID:20972888

  10. Semi-active control of piezoelectric coating's underwater sound absorption by combining design of the shunt impedances

    NASA Astrophysics Data System (ADS)

    Sun, Yang; Li, Zhaohui; Huang, Aigen; Li, Qihu

    2015-10-01

    Piezoelectric shunt damping technology has been applied in the field of underwater sound absorption in recent years. In order to achieve broadband echo reduction, semi-active control of sound absorption of multi-layered piezoelectric coating by shunt damping is significant. In this paper, a practical method is proposed to control the underwater sound absorption coefficients of piezoelectric coating layers by combining design of the shunt impedance that allows certain sound absorption coefficients at setting frequencies. A one-dimensional electro-acoustic model of the piezoelectric coating and the backing is established based on the Mason equivalent circuit theory. First, the shunt impedance of the coating is derived under the constraint of sound absorption coefficient at one frequency. Then, taking the 1-3 piezoelectric composite coating as an example, the sound absorption properties of the coating shunted to the designed shunt impedance are investigated. Next, on the basis of that, an iterative method for two constrained frequencies and an optimizing algorithm for multiple constrained frequencies are provided for combining design of the shunt impedances. At last, an experimental sample with four piezoelectric material layers is manufactured, of which the sound absorption coefficients are measured in an impedance tube. The experimental results show good agreement with the finite element simulation results. It is proved that a serial R-L circuit can control the peak frequency, maximum and bandwidth of the sound absorption coefficient and the combining R-L circuits shunted to multiple layers can control the sound absorption coefficients at multiple frequencies.

  11. Online tuning of impedance matching circuit for long pulse inductively coupled plasma source operation—An alternate approach

    SciTech Connect

    Sudhir, Dass; Bandyopadhyay, M. Chakraborty, A.; Kraus, W.; Gahlaut, A.; Bansal, G.

    2014-01-15

    Impedance matching circuit between radio frequency (RF) generator and the plasma load, placed between them, determines the RF power transfer from RF generator to the plasma load. The impedance of plasma load depends on the plasma parameters through skin depth and plasma conductivity or resistivity. Therefore, for long pulse operation of inductively coupled plasmas, particularly for high power (∼100 kW or more) where plasma load condition may vary due to different reasons (e.g., pressure, power, and thermal), online tuning of impedance matching circuit is necessary through feedback. In fusion grade ion source operation, such online methodology through feedback is not present but offline remote tuning by adjusting the matching circuit capacitors and tuning the driving frequency of the RF generator between the ion source operation pulses is envisaged. The present model is an approach for remote impedance tuning methodology for long pulse operation and corresponding online impedance matching algorithm based on RF coil antenna current measurement or coil antenna calorimetric measurement may be useful in this regard.

  12. Time-Domain Impedance Boundary Conditions for Computational Aeroacoustics

    NASA Technical Reports Server (NTRS)

    Tam, Christopher K. W.; Auriault, Laurent

    1996-01-01

    It is an accepted practice in aeroacoustics to characterize the properties of an acoustically treated surface by a quantity known as impedance. Impedance is a complex quantity. As such, it is designed primarily for frequency-domain analysis. Time-domain boundary conditions that are the equivalent of the frequency-domain impedance boundary condition are proposed. Both single frequency and model broadband time-domain impedance boundary conditions are provided. It is shown that the proposed boundary conditions, together with the linearized Euler equations, form well-posed initial boundary value problems. Unlike ill-posed problems, they are free from spurious instabilities that would render time-marching computational solutions impossible.

  13. Proceedings of the impedance and bunch instability workshop

    SciTech Connect

    Not Available

    1990-04-01

    This report discusses the following topics: impedance and bunch lengthening; single bunch stability in the ESRF; a longitudinal mode-coupling instability model for bunch lengthening; high-frequency behavior of longitudinal coupling impedance; beam-induced energy spreads at beam-pipe transitions; on the calculation of wake functions using MAFIA-T3 code; preliminary measurements of the bunch length and the impedance of LEP; measurements and simulations of collective effects in the CERN SPS; bunch lengthening in the SLC damping rings; and status of impedance measurements for the spring-8 storage ring.

  14. [Cardiac output monitoring by impedance cardiography in cardiac surgery].

    PubMed

    Shimizu, H; Seki, S; Mizuguchi, A; Tsuchida, H; Watanabe, H; Namiki, A

    1990-04-01

    The cardiac output monitoring by impedance cardiography, NCCOM3, was evaluated in adult patients (n = 12) who were subjected to coronary artery bypass grafting. Values of cardiac output measured by impedance cardiography were compared to those by the thermodilution method. Changes of base impedance level used as an index of thoracic fluid volume were also investigated before and after cardiopulmonary bypass (CPB). Correlation coefficient (r) of the values obtained by thermodilution with impedance cardiography was 0.79 and the mean difference was 1.29 +/- 16.9 (SD)% during induction of anesthesia. During the operation, r was 0.83 and the mean difference was -14.6 +/- 18.7%. The measurement by impedance cardiography could be carried out through the operation except when electro-cautery was used. Base impedance level before CPB was significantly lower as compared with that after CPB. There was a negative correlation between the base impedance level and central venous pressure (CVP). No patients showed any signs suggesting lung edema and all the values of CVP, pulmonary artery pressure and blood gas analysis were within normal ranges. From the result of this study, it was concluded that cardiac output monitoring by impedance cardiography was useful in cardiac surgery, but further detailed examinations will be necessary on the relationship between the numerical values of base impedance and the clinical state of the patients. PMID:2362347

  15. Impedance measurements for detecting pathogens attached to antibodies

    DOEpatents

    Miles, Robin R.; Venkateswaran, Kodumudi S.; Fuller, Christopher K.

    2004-12-28

    The use of impedance measurements to detect the presence of pathogens attached to antibody-coated beads. In a fluidic device antibodies are immobilized on a surface of a patterned interdigitated electrode. Pathogens in a sample fluid streaming past the electrode attach to the immobilized antibodies, which produces a change in impedance between two adjacent electrodes, which impedance change is measured and used to detect the presence of a pathogen. To amplify the signal, beads coated with antibodies are introduced and the beads would stick to the pathogen causing a greater change in impedance between the two adjacent electrodes.

  16. Measured longitudinal beam impedance of a Tevatron separator

    SciTech Connect

    James L Crisp; Brian J Fellenz

    2002-12-09

    Twenty two separators are currently installed in the Tevatron. The longitudinal impedance of one of these devices was recently measured with a stretched wire. The stretched wire technique can only measure impedance below the cutoff frequency (500MHz). The geometry of a separator is similar to an un-terminated stripline beam position detector. The separator plates occupy a 13.5'' ID vacuum tank, are 101'' long, 7.8'' wide, and have a 2'' gap between them. The differential characteristic impedance between the plates is estimated to be 81 {Gamma} and the common mode impedance plate to ground is about 42 {Gamma}.

  17. Multi-gap high impedance plasma opening switch

    DOEpatents

    Mason, Rodney J.

    1996-01-01

    A high impedance plasma opening switch having an anode and a cathode and at least one additional electrode placed between the anode and cathode. The presence of the additional electrodes leads to the creation of additional plasma gaps which are in series, increasing the net impedance of the switch. An equivalent effect can be obtained by using two or more conventional plasma switches with their plasma gaps wired in series. Higher impedance switches can provide high current and voltage to higher impedance loads such as plasma radiation sources.

  18. Multi-gap high impedance plasma opening switch

    DOEpatents

    Mason, R.J.

    1996-10-22

    A high impedance plasma opening switch having an anode and a cathode and at least one additional electrode placed between the anode and cathode is disclosed. The presence of the additional electrodes leads to the creation of additional plasma gaps which are in series, increasing the net impedance of the switch. An equivalent effect can be obtained by using two or more conventional plasma switches with their plasma gaps wired in series. Higher impedance switches can provide high current and voltage to higher impedance loads such as plasma radiation sources. 12 figs.

  19. In vivo impedance spectroscopy of deep brain stimulation electrodes

    NASA Astrophysics Data System (ADS)

    Lempka, Scott F.; Miocinovic, Svjetlana; Johnson, Matthew D.; Vitek, Jerrold L.; McIntyre, Cameron C.

    2009-08-01

    Deep brain stimulation (DBS) represents a powerful clinical technology, but a systematic characterization of the electrical interactions between the electrode and the brain is lacking. The goal of this study was to examine the in vivo changes in the DBS electrode impedance that occur after implantation and during clinically relevant stimulation. Clinical DBS devices typically apply high-frequency voltage-controlled stimulation, and as a result, the injected current is directly regulated by the impedance of the electrode-tissue interface. We monitored the impedance of scaled-down clinical DBS electrodes implanted in the thalamus and subthalamic nucleus of a rhesus macaque using electrode impedance spectroscopy (EIS) measurements ranging from 0.5 Hz to 10 kHz. To further characterize our measurements, equivalent circuit models of the electrode-tissue interface were used to quantify the role of various interface components in producing the observed electrode impedance. Following implantation, the DBS electrode impedance increased and a semicircular arc was observed in the high-frequency range of the EIS measurements, commonly referred to as the tissue component of the impedance. Clinically relevant stimulation produced a rapid decrease in electrode impedance with extensive changes in the tissue component. These post-operative and stimulation-induced changes in impedance could play an important role in the observed functional effects of voltage-controlled DBS and should be considered during clinical stimulation parameter selection and chronic animal research studies.

  20. Comprehensive characterization of thermophysical properties in solids using thermal impedance

    NASA Astrophysics Data System (ADS)

    Martínez-Flores, J. J.; Licea-Jiménez, L.; Pérez García, S. A.; Rodríguez-Viejo, J.; Alvarez-Quintana, J.

    2012-11-01

    Thermal impedance Zth(iω) is a way of defining the thermophysical characteristics and behavior of thermal systems. Existing photoacoustic and photothermal approaches based on thermal impedance formalism merely allows a partial thermal characterization of the materials (generally, either thermal diffusivity or thermal effusivity). In this work, a new approach based on the thermal impedance concept in terms of its characteristic thermal time constant is developed from thermal quadrupoles formalism. The approach outlined in this contribution presents a set of analytical equations in which through a single measurement of thermal impedance is sufficient to obtain a comprehensive characterization of the thermophysical properties of solid materials in a simple way.

  1. Impedance measurements on lead-acid batteries for state-of-charge, state-of-health and cranking capability prognosis in electric and hybrid electric vehicles

    NASA Astrophysics Data System (ADS)

    Blanke, Holger; Bohlen, Oliver; Buller, Stephan; De Doncker, Rik W.; Fricke, Birger; Hammouche, Abderrezak; Linzen, Dirk; Thele, Marc; Sauer, Dirk Uwe

    Various attempts have been made to use impedance measurements for online analysis and offline modelling of lead-acid batteries. This presentation gives an overview on the latest and successful approaches based on impedance measurements to assess state-of-charge (SoC), state-of-health (SoH) and cranking capability of lead-acid batteries. Furthermore, it is shown that impedance data can serve as a basis for dynamic battery models for the simulation of vehicle power-supply systems. The methods and procedures aim for a reliable prediction of battery performance in electric vehicles, hybrid cars and classical automotive applications. Although, it will become obvious that impedance measurements give valuable information on the battery state, typically the information needs to be combined with other conventional algorithms or self-learning tools to achieve reliable and stable results for real-world applications.

  2. Corrosion Study Using Electrochemical Impedance Spectroscopy

    NASA Technical Reports Server (NTRS)

    Farooq, Muhammad Umar

    2003-01-01

    Corrosion is a common phenomenon. It is the destructive result of chemical reaction between a metal or metal alloy and its environment. Stainless steel tubing is used at Kennedy Space Center for various supply lines which service the orbiter. The launch pads are also made of stainless steel. The environment at the launch site has very high chloride content due to the proximity to the Atlantic Ocean. Also, during a launch, the exhaust products in the solid rocket boosters include concentrated hydrogen chloride. The purpose of this project was to study various alloys by Electrochemical Impedance Spectroscopy in corrosive environments similar to the launch sites. This report includes data and analysis of the measurements for 304L, 254SMO and AL-6XN in primarily neutral 3.55% NaCl. One set of data for 304L in neutral 3.55%NaCl + 0.1N HCl is also included.

  3. Wave guide impedance matching method and apparatus

    DOEpatents

    Kronberg, James W.

    1990-01-01

    A technique for modifying the end portion of a wave guide, whether hollow or solid, carrying electromagnetic, acoustic or optical energy, to produce a gradual impedance change over the length of the end portion, comprising the cutting of longitudinal, V-shaped grooves that increase in width and depth from beginning of the end portion of the wave guide to the end of the guide so that, at the end of the guide, no guide material remains and no surfaces of the guide as modified are perpendicular to the direction of energy flow. For hollow guides, the grooves are cut beginning on the interior surface; for solid guides, the grooves are cut beginning on the exterior surface. One or more resistive, partially conductive or nonconductive sleeves can be placed over the exterior of the guide and through which the grooves are cut to smooth the transition to free space.

  4. Esophageal Impedance Monitoring for Gastroesophageal Reflux

    PubMed Central

    Mousa, Hayat M.; Rosen, Rachel; Woodley, Frederick W.; Orsi, Marina; Armas, Daneila; Faure, Christophe; Fortunato, John; O'Connor, Judith; Skaggs, Beth; Nurko, Samuel

    2014-01-01

    Dual pH-multichannel intraluminal impedance (pH-MII) is a sensitive tool for evaluating overall gastroesophageal reflux disease, and particularly for permitting detection of nonacid reflux events. pH-MII technology is especially useful in the postprandial period or at other times when gastric contents are nonacidic. pH-MII was recently recognized by the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition as being superior to pH monitoring alone for evaluation of the temporal relation between symptoms and gastroesophageal reflux. In children, pHMII is useful to correlate symptoms with reflux (particularly nonacid reflux), to quantify reflux during tube feedings and the postprandial period, and to assess efficacy of antireflux therapy. This clinical review is simply an evidence-based overview addressing the indications, limitations, and recommended protocol for the clinical use of pH-MII in children. PMID:21240010

  5. Bioelectrical impedance analysis. What does it measure?

    NASA Technical Reports Server (NTRS)

    Schoeller, D. A.

    2000-01-01

    Bioelectrical impedance analysis (BIA) has been proposed for measuring fat-free mass, total body water, percent fat, body cell mass, intracellular water, and extracellular water: a veritable laboratory in a box. Although it is unlikely that BIA is quite this versatile, correlations have been demonstrated between BIA and all of these body compartments. At the same time, it is known that all of the compartments are correlated among themselves. Because of this, it is difficult to determine whether BIA is specific for any or all of these compartments. To investigate this question, we induced acute changes in total body water and its compartments over a 3-h period. Using this approach, we demonstrated that multifrequency BIA, using the Cole-Cole model to calculate the zero frequency and infinite frequency resistance, measures extracellular and intracellular water.

  6. Quartz tuning fork based microwave impedance microscopy

    NASA Astrophysics Data System (ADS)

    Cui, Yong-Tao; Ma, Eric Yue; Shen, Zhi-Xun

    2016-06-01

    Microwave impedance microscopy (MIM), a near-field microwave scanning probe technique, has become a powerful tool to characterize local electrical responses in solid state samples. We present the design of a new type of MIM sensor based on quartz tuning fork and electrochemically etched thin metal wires. Due to a higher aspect ratio tip and integration with tuning fork, such design achieves comparable MIM performance and enables easy self-sensing topography feedback in situations where the conventional optical feedback mechanism is not available, thus is complementary to microfabricated shielded stripline-type probes. The new design also enables stable differential mode MIM detection and multiple-frequency MIM measurements with a single sensor.

  7. Impedance characteristic of the GEC reference cell

    SciTech Connect

    Verdeyen, J.T.; Miller, P.A.

    1992-12-01

    One can make measurements of the electrical parameters (V, I, P) at the access terminals of a reactor, but it is more desirable to relate those parameters to that at the plasma terminals. Toward that end, the authors have made precision impedance measurements over the range of 1-108 MHz on the GEC RF Reference Cell with the plasma terminals open circuited, short circuited and inductively loaded. This enables them to infer an equivalent circuit which is consistent with the geometry of the cell and which agrees with the input measurements to a high degree of accuracy. Using this circuit, one can relate the plasma quantities to the terminal values with the standard ABCD matrix which is valid at all frequencies. The procedure for inferring this circuit and accounting for the resistive losses will be presented.

  8. KRAKEN, a numerical model of RHIC impedances

    SciTech Connect

    Peggs, S.; Mane, V.

    1995-05-01

    The simulation code KRAKEN confirms analytical predictions of head-tail stability criteria, in the presence of momentum dependent linear coupling. It also confirms that resistive wall transverse wake fields are not a serious threat to strong head-tail stability in RHIC, at the vulnerable stage of proton injection. Equation 10, derived from the perspective of two macroparticles, potentially offers a very convenient seminumerical evaluation of the effects of arbitrary transverse wake potentials. It remains to be seen how well the two macroparticle results correlate with simulations using, say, 100 macroparticles. KRAKEN is still under rapid development. Future plans are to include resonant wakefields, multiple bunches, space charge wakefields, betatron detuning, and a connection to the detailed RHIC impedance database.

  9. Impedance matched thin metamaterials make metals absorbing.

    PubMed

    Mattiucci, N; Bloemer, M J; Aközbek, N; D'Aguanno, G

    2013-01-01

    Metals are generally considered good reflectors over the entire electromagnetic spectrum up to their plasma frequency. Here we demonstrate an approach to tailor their absorbing characteristics based on the effective metamaterial properties of thin, periodic metallo-dielectric multilayers by exploiting a broadband, inherently non-resonant, surface impedance matching mechanism. Based on this mechanism, we design, fabricate and test omnidirectional, thin (<1 micron), polarization independent, extremely efficient absorbers (in principle being capable to reach A > 99%) over a frequency range spanning from the UV to the IR. Our approach opens new venues to design cost effective materials for many applications such as thermo-photovoltaic energy conversion devices, light harvesting for solar cells, flat panel display, infrared detectors, stray light reduction, stealth and others. PMID:24220284

  10. Impedance matched thin metamaterials make metals absorbing

    PubMed Central

    Mattiucci, N.; Bloemer, M. J.; Aközbek, N.; D'Aguanno, G.

    2013-01-01

    Metals are generally considered good reflectors over the entire electromagnetic spectrum up to their plasma frequency. Here we demonstrate an approach to tailor their absorbing characteristics based on the effective metamaterial properties of thin, periodic metallo-dielectric multilayers by exploiting a broadband, inherently non-resonant, surface impedance matching mechanism. Based on this mechanism, we design, fabricate and test omnidirectional, thin (<1 micron), polarization independent, extremely efficient absorbers (in principle being capable to reach A > 99%) over a frequency range spanning from the UV to the IR. Our approach opens new venues to design cost effective materials for many applications such as thermo-photovoltaic energy conversion devices, light harvesting for solar cells, flat panel display, infrared detectors, stray light reduction, stealth and others. PMID:24220284

  11. Scheme for rapid adjustment of network impedance

    DOEpatents

    Vithayathil, John J.

    1991-01-01

    A static controlled reactance device is inserted in series with an AC electric power transmission line to adjust its transfer impedance. An inductor (reactor) is serially connected with two back-to-back connected thyristors which control the conduction period and hence the effective reactance of the inductor. Additional reactive elements are provided in parallel with the thyristor controlled reactor to filter harmonics and to obtain required range of variable reactance. Alternatively, the static controlled reactance device discussed above may be connected to the secondary winding of a series transformer having its primary winding connected in series to the transmission line. In a three phase transmission system, the controlled reactance device may be connected in delta configuration on the secondary side of the series transformer to eliminate triplen harmonics.

  12. Efficient reference-free adaptive artifact cancellers for impedance cardiography based remote health care monitoring systems.

    PubMed

    Mallam, Madhavi; Rao, K Chandra Bhutan

    2016-01-01

    In this paper, a new model for adaptive artifact cancelation in impedance cardiography (ICG) signals is presented. It is a hybrid model based on wavelet decomposition and an adaptive filter. A novel feature of this model is the implementation of reference-free adaptive artifact cancellers (AAC). For this implementation, the reference signal is constructed using a wavelet transformation. During critical conditions the filter weights may be negative and cause an imbalance in the convergence. To overcome this problem, we introduce non-negative adaptive algorithms in the proposed artifact canceller. To accelerate the performance of the AAC, we propose exponential non-negative and normalized non-negative algorithms to update the filter coefficients. The computational complexity of the filtering section in a remote health care system is important to avoid inter-symbol interference of the incoming samples. This can be achieved by combining sign-based algorithms with the adaptive filtering section. Finally, several AACs are developed using variants of the non-negative algorithms and performance measures are computed and compared. All of the proposed AACs are tested on actual ICG signals. Among the AACs evaluated, sign regressor normalized non-negative LMS (SRN(3)LMS) based adaptive artifact canceller achieves highest signal to noise ratio (SNR). The SNR achieved by this algorithm in baseline wander artifact elimination is 8.5312 dBs, in electrode muscle artifact elimination is 7.5908 dBs and in impedance measurement artifact elimination is 8.4231 dBs. PMID:27386256

  13. Active acoustical impedance using distributed electrodynamical transducers.

    PubMed

    Collet, M; David, P; Berthillier, M

    2009-02-01

    New miniaturization and integration capabilities available from emerging microelectromechanical system (MEMS) technology will allow silicon-based artificial skins involving thousands of elementary actuators to be developed in the near future. SMART structures combining large arrays of elementary motion pixels coated with macroscopic components are thus being studied so that fundamental properties such as shape, stiffness, and even reflectivity of light and sound could be dynamically adjusted. This paper investigates the acoustic impedance capabilities of a set of distributed transducers connected with a suitable controlling strategy. Research in this domain aims at designing integrated active interfaces with a desired acoustical impedance for reaching an appropriate global acoustical behavior. This generic problem is intrinsically connected with the control of multiphysical systems based on partial differential equations (PDEs) and with the notion of multiscaled physics when a dense array of electromechanical systems (or MEMS) is considered. By using specific techniques based on PDE control theory, a simple boundary control equation capable of annihilating the wave reflections has been built. The obtained strategy is also discretized as a low order time-space operator for experimental implementation by using a dense network of interlaced microphones and loudspeakers. The resulting quasicollocated architecture guarantees robustness and stability margins. This paper aims at showing how a well controlled semidistributed active skin can substantially modify the sound transmissibility or reflectivity of the corresponding homogeneous passive interface. In Sec. IV, numerical and experimental results demonstrate the capabilities of such a method for controlling sound propagation in ducts. Finally, in Sec. V, an energy-based comparison with a classical open-loop strategy underlines the system's efficiency. PMID:19206865

  14. Algorithm development

    NASA Technical Reports Server (NTRS)

    Barth, Timothy J.; Lomax, Harvard

    1987-01-01

    The past decade has seen considerable activity in algorithm development for the Navier-Stokes equations. This has resulted in a wide variety of useful new techniques. Some examples for the numerical solution of the Navier-Stokes equations are presented, divided into two parts. One is devoted to the incompressible Navier-Stokes equations, and the other to the compressible form.

  15. Structural damage assessment of propulsion system components by impedance based health monitoring

    NASA Astrophysics Data System (ADS)

    Martin, Richard E.; Gyekneyesi, Andrew L.; Sawicki, Jerzy T.; Baaklini, George Y.

    2005-05-01

    Critical components of propulsion systems frequently operate at high stress levels for long periods of time. The integrity of these parts must be proven by non-destructive evaluation (NDE) during various manufacturing steps and also during systematic overhaul inspections. Conventional NDE methods, however, have unacceptable limits. Some of these techniques are time-consuming and inconvenient for service aircraft testing. Impedance-based structural-health-monitoring (SHM) uses piezoelectric (PZT) patches that are bonded onto or embedded in a structure; each individual patch both actuates the surrounding structural area and senses the resulting structural response. The size of the excited area varies with the geometry and material composition of the structure. A series of experiments on simple geometry specimens (thin-gage aluminum square plates) was conducted for assessing the potential of E/M impedance method for structural damage detection. Based on the results of this preliminary study, further testing was conducted on a subscale disk specimen. Based on the results it can be concluded that the E/M impedance method has the potential to be used for damage detection of structures. The experimental method, signal processing, and damage detection algorithm should be tuned to the specific method used for structural interrogation.

  16. Detection of High-impedance Arcing Faults in Radial Distribution DC Systems

    NASA Technical Reports Server (NTRS)

    Gonzalez, Marcelo C.; Button, Robert M.

    2003-01-01

    High voltage, low current arcing faults in DC power systems have been researched at the NASA Glenn Research Center in order to develop a method for detecting these 'hidden faults', in-situ, before damage to cables and components from localized heating can occur. A simple arc generator was built and high-speed and low-speed monitoring of the voltage and current waveforms, respectively, has shown that these high impedance faults produce a significant increase in high frequency content in the DC bus voltage and low frequency content in the DC system current. Based on these observations, an algorithm was developed using a high-speed data acquisition system that was able to accurately detect high impedance arcing events induced in a single-line system based on the frequency content of the DC bus voltage or the system current. Next, a multi-line, radial distribution system was researched to see if the arc location could be determined through the voltage information when multiple 'detectors' are present in the system. It was shown that a small, passive LC filter was sufficient to reliably isolate the fault to a single line in a multi-line distribution system. Of course, no modification is necessary if only the current information is used to locate the arc. However, data shows that it might be necessary to monitor both the system current and bus voltage to improve the chances of detecting and locating high impedance arcing faults

  17. A Monte Carlo simulation of range for an invasive impedance respiration monitor.

    PubMed

    Valenta, H L; Fischer, S K

    1990-01-01

    One method of rate responsive pacing utilizes an analog of minute ventilation as the input to the rate control algorithm. A measure of the intravenous impedance along the pacing catheter is a convenient means of determining minute ventilation. Design of the impedance converter requires a knowledge of the range of DC and AC impedance signals. During normal and deep breathing, 116 AC measurements were taken from 34 Electrophysiology (EP) patients and 31 DC measurements were taken from 13 EP patients. The patient data produced skewed distributions with a normal AC mean of 0.45 +/- 0.40 ohms p-p, a deep AC mean of 2.0 +/- 1.6 ohms and a DC mean of 44 +/- 13 ohms. An eight variable static model was derived from prior work. Five of the physiological variables were chosen from established clinical ranges, one geometrical variable was chosen from prior work and two were selected by matching the statistics of a Monte Carlo analysis of the model with the statistics of the patient data. The blood resistivity was obtained from prior work. A simulation of 1000 measurements produced a normal breathing range of 0 to 2.24 ohms, a deep breathing range of 0 to 9.6 ohms and a DC range of 19 to 100 ohms. PMID:2334765

  18. Artificial neural network classification of pharyngeal high-resolution manometry with impedance data

    PubMed Central

    Hoffman, Matthew R.; Mielens, Jason D.; Omari, Taher I.; Rommel, Nathalie; Jiang, Jack J.; McCulloch, Timothy M.

    2013-01-01

    Purpose To use classification algorithms to classify swallows as safe, penetration, or aspiration based on measurements obtained from pharyngeal high-resolution manometry (HRM) with impedance. Study design Case series evaluating new method of data analysis. Method Multilayer perceptron (MLP), an artificial neural network (ANN), was evaluated for its ability to classify swallows as safe, penetration, or aspiration. Data were collected from 25 disordered subjects swallowing 5 or 10 ml boluses. Following extraction of relevant parameters, a subset of the data was used to train the models and the remaining swallows were then independently classified by the ANN. Results A classification accuracy of 89.4±2.4% was achieved when including all parameters. Including only manometry-related parameters yielded a classification accuracy of 85.0±6.0% while including only impedance-related parameters yielded a classification accuracy of 76.0±4.9%. Receiver operating characteristic (ROC) analysis yielded areas under the curve (AUC) of 0.8912 for safe, 0.8187 for aspiration, and 0.8014 for penetration. Conclusions Classification models show high accuracy in classifying swallows from dysphagic patients as safe or unsafe. HRM-impedance with ANN represents one method which could be used clinically to screen for patients at risk for penetration or aspiration. PMID:23070810

  19. Magnetic resonance electrical impedance tomography (MREIT): conductivity and current density imaging

    NASA Astrophysics Data System (ADS)

    Seo, Jin Keun; Kwon, Ohin; Woo, Eung Je

    2005-01-01

    This paper reviews the latest impedance imaging technique called Magnetic Resonance Electrical Impedance Tomography (MREIT) providing information on electrical conductivity and current density distributions inside an electrically conducting domain such as the human body. The motivation for this research is explained by discussing conductivity changes related with physiological and pathological events, electromagnetic source imaging and electromagnetic stimulations. We briefly summarize the related technique of Electrical Impedance Tomography (EIT) that deals with cross-sectional image reconstructions of conductivity distributions from boundary measurements of current-voltage data. Noting that EIT suffers from the ill-posed nature of the corresponding inverse problem, we introduce MREIT as a new conductivity imaging modality providing images with better spatial resolution and accuracy. MREIT utilizes internal information on the induced magnetic field in addition to the boundary current-voltage measurements to produce three-dimensional images of conductivity and current density distributions. Mathematical theory, algorithms, and experimental methods of current MREIT research are described. With numerous potential applications in mind, future research directions in MREIT are proposed.

  20. Clinical application of Electrical Impedance Tomography in the Present Health Scenario of India

    NASA Astrophysics Data System (ADS)

    Chakraborti, K. L., Dr; Selvamurthy, W., Dr

    2010-04-01

    Early detection of Breast Cancer is currently emerging as a big clinical entity requiring a non invasive, radiation less, harmless, cost effective diagnostic technique. Survival is improved if detected early. Breast Cancer is the second most common cancer in India. Health corporate system of India is urgently requiring a cost effective, noninvasive novel technique like "Electrical Impedance Tomography (EIT)" for screening large poor rural population of India for early diagnosis of Breast Cancer. EIT is the technique to visualize spatial distribution of Electro-impedance (or conductivity) inside the object, such as human body. A medical device which allows imaging of the distribution of conductivity in 3D in regions below the skin surface has been developed and tested. Its purpose is to enable early detection and preliminary diagnosis of breast tumors. The system uses a planar array consisting of 256 electrodes and enables obtaining images of the three-dimensional conductivity distribution in regions below the skin's surface up to several centimeters deep. The developed measuring system and image reconstruction algorithm can be used for breast tissue imaging and diagnostic, in particular for malignant tumor detection. Initially ten patients as control and ten patients with breast lesions have been studied with this new technique. It was found that electrical impedance mammograms from different groups has clear visual distinctions and statistically significant difference in breast glands conductivity. The results are quiet encouraging. EIT may emerge as the first line noninvasive imaging method of choice for screening large population for early detection of breast cancer.

  1. Preliminary Results on Different Impedance Contrast Agents for Pulmonary Perfusion Imaging with Electrical Impedance Tomography

    NASA Astrophysics Data System (ADS)

    Nguyen, D. T.; Kosobrodov, R.; Barry, M. A.; Chik, W.; Pouliopoulos, J.; Oh, T. I.; Thiagalingam, A.; McEwan, A.

    2013-04-01

    Recent studies in animal models suggest that the use of small volume boluses of NaCl as an impedance contrast agent can significantly improve pulmonary perfusion imaging by Electrical Impedance Tomography (EIT). However, these studies used highly concentrated NaCl solution (20%) which may have adverse effects on the patients. In a pilot experiment, we address this problem by comparing a number of different Impedance Contrast Boluses (ICBs). Conductivity changes in the lungs of a sheep after the injection of four different ICBs were compared, including three NaCl-based ICBs and one glucose-based ICB. The following procedure was followed for each ICB. Firstly, ventilation was turned off to provide an apneic window of approximately 40s to image the conductivity changes due to the ICB. Each ICB was then injected through a pig-tail catheter directly into the right atrium. EIT images were acquired throughout the apnea to capture the conductivity change. For each ICB, the experiment was repeated three times. The three NaCl-based ICB exhibited similar behaviour in which following the injection of each of these ICBs, the conductivity of each lung predictably increased. The effect of the ICB of 5% glucose solution was inconclusive. A small decrease in conductivity in the left lung was observed in two out of three cases and none was discernible in the right lung.

  2. The Impedance Response of Semiconductors: An Electrochemical Engineering Perspective.

    ERIC Educational Resources Information Center

    Orazem, Mark E.

    1990-01-01

    Shows that the principles learned in the study of mass transport, thermodynamics, and kinetics associated with electrochemical systems can be applied to the transport and reaction processes taking place within a semiconductor. Describes impedance techniques and provides several graphs illustrating impedance data for diverse circuit systems. (YP)

  3. Impedance Matching of Tapered Slot Antenna using a Dielectric Transformer

    NASA Technical Reports Server (NTRS)

    Simons, R. N.; Lee, R. Q.

    1998-01-01

    A new impedance matching technique for tapered slot antennas using a dielectric transformer is presented. The technique is demonstrated by measuring the input impedance, Voltage Standing Wave Ratio (VSWR) and the gain of a Vivaldi antenna (VA). Measured results at Ka-Band frequencies are presented and discussed.

  4. An Inexpensive, Very High Impedance Digital Voltmeter for Selective Electrodes.

    ERIC Educational Resources Information Center

    Caceci, Marco S.

    1984-01-01

    Describes a compact, digital voltmeter which exceeds, both in accuracy and input impedance, most commercial pH meters and potentiometers. The instrument consists of two parts: a very high impedance hybrid operational amplifier used as a voltage follower (ICH8500/A, Intersil) and a four and one-half digits LED display panel meter (RP-4500,…

  5. Flip-Chip Carrier Would Match Microwave FET Impedances

    NASA Technical Reports Server (NTRS)

    Huang, H. C.

    1982-01-01

    Proposed field-effect transistor consists of three cells which make up one complete FET pellet. Pellet is flip-chip mounted on carrier with source grounded gate and drain posts connected directly to impedance-matching transmission-line segments. Impedance transformers are part of mounting and contact strips.

  6. Equivalent circuit models for ac impedance data analysis

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1990-01-01

    A least-squares fitting routine has been developed for the analysis of ac impedance data. It has been determined that the checking of the derived equations for a particular circuit with a commercially available electronics circuit program is essential. As a result of the investigation described, three equivalent circuit models were selected for use in the analysis of ac impedance data.

  7. Geometric beam coupling impedance of LHC secondary collimators

    NASA Astrophysics Data System (ADS)

    Frasciello, Oscar; Tomassini, Sandro; Zobov, Mikhail; Salvant, Benoit; Grudiev, Alexej; Mounet, Nicolas

    2016-02-01

    The High Luminosity LHC project is aimed at increasing the LHC luminosity by an order of magnitude. One of the key ingredients to achieve the luminosity goal is the beam intensity increase. In order to keep beam instabilities under control and to avoid excessive power losses a careful design of new vacuum chamber components and an improvement of the present LHC impedance model are required. Collimators are among the major impedance contributors. Measurements with beam have revealed that the betatron coherent tune shifts were higher by about a factor of 2 with respect to the theoretical predictions based on the LHC impedance model up to 2012. In that model the resistive wall impedance has been considered as the dominating impedance contribution for collimators. By carefully simulating also their geometric impedance we have contributed to the update of the LHC impedance model, reaching also a better agreement between the measured and simulated betatron tune shifts. During the just ended LHC Long Shutdown I (LSI), TCS/TCT collimators were replaced by new devices embedding BPMs and TT2-111R ferrite blocks. We present here preliminary estimations of their broad-band impedance, showing that an increase of about 20% is expected in the kick factors with respect to previous collimators without BPMs.

  8. Electrochemical impedance measurement of a carbon nanotube probe electrode.

    PubMed

    Inaba, Akira; Takei, Yusuke; Kan, Tetsuo; Matsumoto, Kiyoshi; Shimoyama, Isao

    2012-12-01

    We measured and analyzed the electrochemical impedance of carbon nanotube (CNT) probe electrodes fabricated through the physical separation of insulated CNT bridges. The fabricated CNT electrodes were free-standing CNTs that were completely covered with an insulator, except for their tips. Typical dimensions of the nanoelectrodes were 1-10 nm in CNT diameter, 80-300 nm in insulator diameter, 0.5-4 μm in exposed CNT length and 1-10 μm in probe length. The electrochemical impedance at frequencies ranging from 40 Hz to 1 MHz was measured in physiological saline. The measured impedance of the CNT electrode was constant at 32 MΩ at frequencies below 1 kHz and was inversely proportional to frequency at frequencies above 10 kHz. By means of comparison with the parasitic capacitive impedance of the insulator membrane, we confirmed that the electrode was sufficiently insulated such that the measured constant impedance was given by the exposed CNT tip. Consequently, we can use the CNT electrode for highly localized electrochemical impedance measurements below 1 kHz. Considering an equivalent circuit and the nanoscopic dimensions of the CNT electrode, we demonstrated that the constant impedance was governed by diffusion impedance, whereas the solution resistance, charge-transfer resistance and double-layer capacitance were negligible. PMID:23124171

  9. An Alternative to Impedance Screening: Unoccluded Frontal Bone Conduction Screening.

    ERIC Educational Resources Information Center

    Square, Regina; And Others

    1985-01-01

    A bone conduction hearing screening test using frontal bone oscillator placement was compared with pure-tone air-conduction screening and impedance audiometry with 114 preschoolers. Unoccluded frontal bone conduction testing produced screening results not significantly different from results obtained by impedance audiometry. (CL)!

  10. Surface impedance in the anomalous skin effect regime

    NASA Astrophysics Data System (ADS)

    Chrzanowski, Janusz; Kirkiewicz, Józef

    2008-12-01

    An analytical solution of the surface impedance is obtained using the kinetic equation with the collision integral that takes into account the Fermi liquid effects. It is assumed that the reflection of electrons is purely diffusive. Particular attention is paid to the influence of external magnetic field and polarization of the incident wave on the real and imagine part of the surface impedance.

  11. Effect of Feeding and Suction on Gastric Impedance Spectroscopy Measurements.

    PubMed

    Beltran, Nohra E; Sánchez-Miranda, Gustavo; Sacristan, Emilio

    2015-01-01

    A specific device and system has been developed and tested for clinical monitoring of gastric mucosal reactance in the critically ill as an early warning of splanchnic hypoperfusion associated with shock and sepsis. This device has been proven effective in clinical trials and is expected to become commercially available next year. The system uses a combination nasogastric tube and impedance spectroscopy probe as a single catheter. Because this device has a double function, the question is: Does enteral feeding or suction affect the gastric reactance measurements? This study was designed to evaluate the effect of feeding and suction on the measurement of gastric impedance spectroscopy in healthy volunteers. Impedance spectra were obtained from the gastric wall epithelia of 18 subjects. The spectra were measured for each of the following conditions: postinsertion of gastric probe, during active suction, postactive suction, and during enteral feeding (236 ml of nutritional supplement). Impedance spectra were reproducible in all volunteers under all conditions tested. There was a slight increase in impedance parameters after suction, and a decrease in impedance after feeding; however, these observed differences were insignificant compared to patient-to-patient variability, and truly negligible compared with previously observed changes associated with splanchnic ischemia in critically ill patients. Our results demonstrate that suction or feeding when using the impedance spectro-metry probe/nasogastric tube does not significantly interfere with gastric impedance spectrometer measurements. PMID:26226020

  12. Development of impedance matching technologies for ICRF antenna arrays

    SciTech Connect

    Pinsker, R.I.

    1998-03-01

    All high power ICRF heating systems include devices for matching the input impedance of the antenna array to the generator output impedance. For most types of antennas used, the input impedance is strongly time-dependent on timescales as rapid as 10-4 s, while the rf generators used are capable of producing full power only into a stationary load impedance. Hence, the dynamic response of the matching method is of great practical importance. In this paper, world-wide developments in this field over the past decade are reviewed. These techniques may be divided into several classes. The edge plasma parameters that determine the antenna array`s input impedance may be controlled to maintain a fixed load impedance. The frequency of the rf source can be feedback controlled to compensate for changes in the edge plasma conditions, or fast variable tuning elements in the transmission line between the generator output and the antenna input connections can provide the necessary time-varying impedance transformation. In lossy passive schemes, reflected power due to the time-varying impedance of the antenna array is diverted to a dummy load. Each of these techniques can be applied to a pre-existing antenna system. If a new antenna is to be designed, recent advances allow the antenna array to have the intrinsic property of presenting a constant load to the feeding transmission lines despite the varying load seen by each antenna in the array.

  13. Modifying the acoustic impedance of polyurea-based composites

    NASA Astrophysics Data System (ADS)

    Nantasetphong, Wiroj; Amirkhizi, Alireza V.; Jia, Zhanzhan; Nemat-Nasser, Sia

    2013-04-01

    Acoustic impedance is a material property that depends on mass density and acoustic wave speed. An impedance mismatch between two media leads to the partial reflection of an acoustic wave sent from one medium to another. Active sonar is one example of a useful application of this phenomenon, where reflected and scattered acoustic waves enable the detection of objects. If the impedance of an object is matched to that of the surrounding medium, however, the object may be hidden from observation (at least directly) by sonar. In this study, polyurea composites are developed to facilitate such impedance matching. Polyurea is used due to its excellent blast-mitigating properties, easy casting, corrosion protection, abrasion resistance, and various uses in current military technology. Since pure polyurea has impedance higher than that of water (the current medium of interest), low mass density phenolic microballoon particles are added to create composite materials with reduced effective impedances. The volume fraction of particles is varied to study the effect of filler quantity on the acoustic impedance of the resulting composite. The composites are experimentally characterized via ultrasonic measurements. Computational models based on the method of dilute-randomly-distributed inclusions are developed and compared with the experimental results. These experiments and models will facilitate the design of new elastomeric composites with desirable acoustic impedances.

  14. Development on electromagnetic impedance function modeling and its estimation

    SciTech Connect

    Sutarno, D.

    2015-09-30

    Today the Electromagnetic methods such as magnetotellurics (MT) and controlled sources audio MT (CSAMT) is used in a broad variety of applications. Its usefulness in poor seismic areas and its negligible environmental impact are integral parts of effective exploration at minimum cost. As exploration was forced into more difficult areas, the importance of MT and CSAMT, in conjunction with other techniques, has tended to grow continuously. However, there are obviously important and difficult problems remaining to be solved concerning our ability to collect process and interpret MT as well as CSAMT in complex 3D structural environments. This talk aim at reviewing and discussing the recent development on MT as well as CSAMT impedance functions modeling, and also some improvements on estimation procedures for the corresponding impedance functions. In MT impedance modeling, research efforts focus on developing numerical method for computing the impedance functions of three dimensionally (3-D) earth resistivity models. On that reason, 3-D finite elements numerical modeling for the impedances is developed based on edge element method. Whereas, in the CSAMT case, the efforts were focused to accomplish the non-plane wave problem in the corresponding impedance functions. Concerning estimation of MT and CSAMT impedance functions, researches were focused on improving quality of the estimates. On that objective, non-linear regression approach based on the robust M-estimators and the Hilbert transform operating on the causal transfer functions, were used to dealing with outliers (abnormal data) which are frequently superimposed on a normal ambient MT as well as CSAMT noise fields. As validated, the proposed MT impedance modeling method gives acceptable results for standard three dimensional resistivity models. Whilst, the full solution based modeling that accommodate the non-plane wave effect for CSAMT impedances is applied for all measurement zones, including near-, transition

  15. Development on electromagnetic impedance function modeling and its estimation

    NASA Astrophysics Data System (ADS)

    Sutarno, D.

    2015-09-01

    Today the Electromagnetic methods such as magnetotellurics (MT) and controlled sources audio MT (CSAMT) is used in a broad variety of applications. Its usefulness in poor seismic areas and its negligible environmental impact are integral parts of effective exploration at minimum cost. As exploration was forced into more difficult areas, the importance of MT and CSAMT, in conjunction with other techniques, has tended to grow continuously. However, there are obviously important and difficult problems remaining to be solved concerning our ability to collect process and interpret MT as well as CSAMT in complex 3D structural environments. This talk aim at reviewing and discussing the recent development on MT as well as CSAMT impedance functions modeling, and also some improvements on estimation procedures for the corresponding impedance functions. In MT impedance modeling, research efforts focus on developing numerical method for computing the impedance functions of three dimensionally (3-D) earth resistivity models. On that reason, 3-D finite elements numerical modeling for the impedances is developed based on edge element method. Whereas, in the CSAMT case, the efforts were focused to accomplish the non-plane wave problem in the corresponding impedance functions. Concerning estimation of MT and CSAMT impedance functions, researches were focused on improving quality of the estimates. On that objective, non-linear regression approach based on the robust M-estimators and the Hilbert transform operating on the causal transfer functions, were used to dealing with outliers (abnormal data) which are frequently superimposed on a normal ambient MT as well as CSAMT noise fields. As validated, the proposed MT impedance modeling method gives acceptable results for standard three dimensional resistivity models. Whilst, the full solution based modeling that accommodate the non-plane wave effect for CSAMT impedances is applied for all measurement zones, including near-, transition

  16. Plasmonic-Based Electrochemical Impedance Spectroscopy: Application to Molecular Binding

    PubMed Central

    Lu, Jin; Wang, Wei; Wang, Shaopeng; Shan, Xiaonan; Li, Jinghong; Tao, Nongjian

    2012-01-01

    Plasmonic-based electrochemical impedance spectroscopy (P-EIS) is developed to investigate molecular binding on surfaces. Its basic principle relies on the sensitive dependence of surface plasmon resonance (SPR) signal on surface charge density, which is modulated by applying an AC potential to a SPR chip surface. The AC component of the SPR response gives the electrochemical impedance, and the DC component provides the conventional SPR detection. The plasmonic-based impedance measured over a range of frequency is in quantitative agreement with the conventional electrochemical impedance. Compared to the conventional SPR detection, P-EIS is sensitive to molecular binding taking place on the chip surface, and less sensitive to bulk refractive index changes or non-specific binding. Moreover, this new approach allows for simultaneous SPR and surface impedance analysis of molecular binding processes. PMID:22122514

  17. Utilization of bone impedance for age estimation in postmortem cases.

    PubMed

    Ishikawa, Noboru; Suganami, Hideki; Nishida, Atsushi; Miyamori, Daisuke; Kakiuchi, Yasuhiro; Yamada, Naotake; Wook-Cheol, Kim; Kubo, Toshikazu; Ikegaya, Hiroshi

    2015-11-01

    In the field of Forensic Medicine the number of unidentified cadavers has increased due to natural disasters and international terrorism. The age estimation is very important for identification of the victims. The degree of sagittal closure is one of such age estimation methods. However it is not widely accepted as a reliable method for age estimation. In this study, we have examined whether measuring impedance value (z-values) of the sagittal suture of the skull is related to the age in men and women and discussed the possibility to use bone impedance for age estimation. Bone impedance values increased with aging and decreased after the age of 64.5. Then we compared age estimation through the conventional visual method and the proposed bone impedance measurement technique. It is suggested that the bone impedance measuring technique may be of value to forensic science as a method of age estimation. PMID:26421720

  18. AC impedance study of degradation of porous nickel battery electrodes

    NASA Technical Reports Server (NTRS)

    Lenhart, Stephen J.; Macdonald, D. D.; Pound, B. G.

    1987-01-01

    AC impedance spectra of porous nickel battery electrodes were recorded periodically during charge/discharge cycling in concentrated KOH solution at various temperatures. A transmission line model (TLM) was adopted to represent the impedance of the porous electrodes, and various model parameters were adjusted in a curve fitting routine to reproduce the experimental impedances. Degradation processes were deduced from changes in model parameters with electrode cycling time. In developing the TLM, impedance spectra of planar (nonporous) electrodes were used to represent the pore wall and backing plate interfacial impedances. These data were measured over a range of potentials and temperatures, and an equivalent circuit model was adopted to represent the planar electrode data. Cyclic voltammetry was used to study the characteristics of the oxygen evolution reaction on planar nickel electrodes during charging, since oxygen evolution can affect battery electrode charging efficiency and ultimately electrode cycle life if the overpotential for oxygen evolution is sufficiently low.

  19. Does combing the scalp reduce scalp electrode impedances?

    PubMed

    Mahajan, Yatin; McArthur, Genevieve

    2010-05-15

    Electrical activity from the human brain can be recorded via electrodes on the scalp. It is important to reduce the impedance of each electrode to minimize unwanted noise in the recording. Electrode impedance can be improved by abrading the skin to remove dead skin cells. In this experiment, we tested if abrading the skin by combing the scalp leads to a significant reduction in electrode impedance. We compared the mean electrode impedance values of 20 subjects whose scalps were combed prior to electrode cap placement, with 20 subjects whose scalps were not combed. Combing significantly reduced the impedances at central, right, and left areas of the scalp. This finding supports the use of scalp combing to reduce the time and subject discomfort that can be associated with placing scalp electrodes. This is particularly important for experiments testing children. PMID:20211649

  20. Finite difference time domain implementation of surface impedance boundary conditions

    NASA Technical Reports Server (NTRS)

    Beggs, John H.; Luebbers, Raymond J.; Yee, Kane S.; Kunz, Karl S.

    1991-01-01

    Surface impedance boundary conditions are employed to reduce the solution volume during the analysis of scattering from lossy dielectric objects. In the finite difference solution, they also can be utilized to avoid using small cells, made necessary by shorter wavelengths in conducting media throughout the solution volume. The standard approach is to approximate the surface impedance over a very small bandwidth by its value at the center frequency, and then use that result in the boundary condition. Here, two implementations of the surface impedance boundary condition are presented. One implementation is a constant surface impedance boundary condition and the other is a dispersive surface impedance boundary condition that is applicable over a very large frequency bandwidth and over a large range of conductivities. Frequency domain results are presented in one dimension for two conductivity values and are compared with exact results. Scattering width results from an infinite square cylinder are presented as a two dimensional demonstration. Extensions to three dimensions should be straightforward.