The effect of high-frequency electric pulses on tumor blood flow in vivo

Abstract The aim of this study was to evaluate the effect of a 5-kHz repetition frequency of electroporating electric pulses in comparison to the standard 1-Hz frequency on blood flow of invasive ductal carcinoma tumors in Balb/C mice. Electroporation was performed by the delivery of eight electric pulses of 1,000 V cm-1 and 100 ls duration at a repetition frequency of 1 Hz or 5 kHz. Blood flow changes in tumors were measured by laser Doppler flowmetry. Monitoring was performed continuously for 10 min before application of the electric pulses as well as immediately after application of the electric pulses for 40 min. The delivery of electric pulses to tumors induced changes in tumor blood flow. The reduction in blood flow started after the stimulation and continued for the 40-min period of observation. There was a significant difference in blood flow changes 3 min after application of the electric pulses at 1-Hz or 5-kHz repetition frequency. However, after 3 min the difference became nonsignificant. The findings showed that the high pulse frequency (5 kHz) had an effect comparable to the 1-Hz frequency on tumor blood flow except at very short times after pulse delivery, when pulses at 5 kHz produced a more intense reduction of blood flo

Improvement of Secondary Sedimentation Tanks in the Presence of a Baffle

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Ge/SiGe parabolic quantum wells

Quantum wells with parabolic confining potentials allow the realization of semiconductor heterostructures mimicking the physical properties of a quantum harmonic oscillator. Here we report the attempt of attaining such parabolic quantum wells (PQWs) within the Ge/SiGe material platform. Multiple PQWs featuring different widths and composition have been epitaxially grown and characterized by means of high-resolution x-ray diffraction and scanning transmission electron microscopy. The compositional profile is seen to deviate slightly from an ideal parabola, but the quantum confined states are almost equally spaced within the valence and conduction band as indicated by photoreflectance measurements and k . p modelling

Predicting the spontaneous termination of atrial fibrillation based on Poincare section in the electrocardiogram phase space

Atrial fibrillation (AF) is a commonly encountered cardiac arrhythmia. Predicting the conditions under which AF terminates spontaneously is an important task that would bring great benefit to both patients and clinicians. In this study, a new method was proposed to predict spontaneous AF termination by employing the points of section (POS) coordinates along a Poincare section in the electrocardiogram (ECG) phase space. The AF Termination Database provided by PhysioNet for the Computers in Cardiology Challenge 2004 was applied in the present study. It includes one training dataset and two testing datasets, A and B. The present investigation was initiated by producing a two-dimensional reconstructed phase space (RPS) of the ECG. Then, a Poincare line was drawn in a direction that included the maximum point distribution in the RPS and also passed through the origin of the RPS coordinate system. Afterward, the coordinates of the RPS trajectory intersections with this Poincare line were extracted to capture the local behavior related to the arrhythmia under investigation. The POS corresponding to atrial activity were selected with regard to the fact that similar ECG morphologies such as P waves, which are corresponding to atrial activity, distribute in a specific region of the RPS. Thirteen features were extracted from the selected intersection points to quantify their distributions. To select the best feature subset, a genetic algorithm (GA), in combination with a support vector machine (SVM), was applied to the training dataset. Based on the selected features and trained SVM, the performance of the proposed method was evaluated using the testing datasets. The results showed that 86.67 of dataset A and 80 of dataset B were correctly classified. This classification accuracy is in the same range as or higher than that of recent studies in this area. These results show that the proposed method, in which no complicated QRST cancelation algorithm was used, has the potential to predict AF termination. © IMechE 2011

Real-Gas Effects and Phase Separation in Underexpanded Jets at Engine-Relevant Conditions

A numerical framework implemented in the open-source tool OpenFOAM is presented in this work combining a hybrid, pressure-based solver with a vapor-liquid equilibrium model based on the cubic equation of state. This framework is used in the present work to investigate underexpanded jets at engine-relevant conditions where real-gas effects and mixture induced phase separation are probable to occur. A thorough validation and discussion of the applied vapor-liquid equilibrium model is conducted by means of general thermodynamic relations and measurement data available in the literature. Engine-relevant simulation cases for two different fuels were defined. Analyses of the flow field show that the used fuel has a first order effect on the occurrence of phase separation. In the case of phase separation two different effects could be revealed causing the single-phase instability, namely the strong expansion and the mixing of the fuel with the chamber gas. A comparison of single-phase and two-phase jets disclosed that the phase separation leads to a completely different penetration depth in contrast to single-phase injection and therefore commonly used analytical approaches fail to predict the penetration depth.Comment: Preprint submitted to AIAA Scitech 2018, Kissimmee, Florid

Sacral Fractures and Associated Injuries.

STUDY DESIGN: Literature review. OBJECTIVE: The aim of this review is to describe the injuries associated with sacral fractures and to analyze their impact on patient outcome. METHODS: A comprehensive narrative review of the literature was performed to identify the injuries associated with sacral fractures. RESULTS: Sacral fractures are uncommon injuries that result from high-energy trauma, and that, due to their rarity, are frequently underdiagnosed and mistreated. Only 5% of sacral fractures occur in isolation. Injuries most often associated with sacral fractures include neurologic injuries (present in up to 50% of sacral fractures), pelvic ring disruptions, hip and lumbar spine fractures, active pelvic/ abdominal bleeding and the presence of an open fracture or significant soft tissue injury. Diagnosis of pelvic ring fractures and fractures extending to the lumbar spine are key factors for the appropriate management of sacral fractures. Importantly, associated systemic (cranial, thoracic, and abdominopelvic) or musculoskeletal injuries should be promptly assessed and addressed. These associated injuries often dictate the management and eventual outcome of sacral fractures and, therefore, any treatment algorithm should take them into consideration. CONCLUSIONS: Sacral fractures are complex in nature and often associated with other often-missed injuries. This review summarizes the most relevant associated injuries in sacral fractures and discusses on their appropriate management

The Development of a Universally Accepted Sacral Fracture Classification: A Survey of AOSpine and AOTrauma Members.

Study Design Survey study. Objective To determine the global perspective on controversial aspects of sacral fracture classifications. Methods While developing the AOSpine Sacral Injury Classification System, a survey was sent to all members of AOSpine and AOTrauma. The survey asked four yes-or-no questions to help determine the best way to handle controversial aspects of sacral fractures in future classifications. Chi-square tests were initially used to compare surgeons\u27 answers to the four key questions of the survey, and then the data was modeled through multivariable logistic regression analysis. Results A total of 474 surgeons answered all questions in the survey. Overall 86.9% of respondents felt that the proposed hierarchical nature of injuries was appropriate, and 77.8% of respondents agreed that that the risk of neurologic injury is highest in a vertical fracture through the foramen. Almost 80% of respondents felt that the separation of injuries based on the integrity of L5-S1 facet was appropriate, and 83.8% of surgeons agreed that a nondisplaced sacral U fracture is a clinically relevant entity. Conclusion This study determines the global perspective on controversial areas in the injury patterns of sacral fractures and demonstrates that the development of a comprehensive and universally accepted sacral classification is possible

Striae gravidarum: Associated factors

Background: Striae gravidarum (SG) is the most common change in connective tissue of pregnant women and may cause cosmetic concerns. Objectives: To determine the frequency of SG in Iranian pregnant women and its possible associations with the characteristics of themselves and their newborns. Methods: One hundred and eighteen primigravid pregnant women were included in this prospective observational study at their first prenatal visit, among them 114 completed the study and gave birth. Results: One hundred (87.7) of 114 women developed SG with a mean Davey's score of 4.04±2.47. The mean gestational age at which SG first appeared was 27.57±5.38 weeks. Family history of SG in mother, baseline and delivery body mass index, greatest abdominal and hip girths, newborn weight, height and head circumference were significantly associated with the presence of SG. All of these factors were also correlated with Davey's score. Conclusion: Genetic and physical risk factors may be involved in the development of SG in primigravid women. © 2007 The Authors Journal compilation © 2007 European Academy of Dermatology and Venereology

Effective Treatment of Cervical Lymph Node Metastasis of Breast Cancer by Low Voltage High-Frequency Electrochemotherapy

Electrochemotherapy (ECT) is a new local treatment method for solid and superficial tumors. During this new technique, patients experience an unpleasant sensation and slight edema. Most unpleasant and painful is mainly attributed to muscle contractions provoked by high amplitude and low repetition frequency pulses. Recently, we showed that electrochemotherapy using low voltage and higher repetition frequency (LVHF ECT) is an effective tool for inhibiting tumor growth and inducing cell permeabilization. Low voltage high-frequency electrochemotherapy was developed and optimized in vitro and in vivo which and can be used in the clinic. In the present study, we report a case of cervical lymph node metastasis of breast cancer treated by the technique. In our case, LVHF ECT was successful in reducing the size and palliating the symptoms of cervical lymph node metastasis in clinical conditions, whereas other approaches were inefficient. Our electrochemotherapy technique shows good clinical results. However, more studies on this new method are necessary to prove that LVHF ECT can be considered as a standard treatment modality

Concepts of patients with alopecia areata about their disease

BACKGROUND: Alopecia areata (AA) is a common and chronic skin disease with an unknown etiology. It may significantly affect the patient quality of life. This study was designed to evaluate the illness perception in patients with AA. METHODS: A questionnaire consisting of 25 questions about causes, timeline, consequences and control of disease were given to 80 patients with AA attending a skin clinic in Tehran, Iran. The impact of age, gender, duration of disease, education, extent of disease and family history of AA were also assessed. RESULTS: Eighty patients (38 male and 42 female) with a mean age of 27.5 years (SD = 9.3) and disease duration of 7.8 years (SD = 7.7) completed the questionnaire. 76.9% of the patients believed that the role of stress was the cause of disease. 17.1 % believed genetic background to be the main cause, this found to be more frequent in patients with positive family history of AA. More than half of patients believed that their illness had major consequences on their lives and 40% of patients believed that their illness would be likely to be permanent rather than temporary, more in patients with longer duration of disease. Only 57.5% of patients considered their treatments to be effective. CONCLUSION: AA may considerably affect various aspects of patients' lives. The patient knowledge about the causes and course of this disease is limited