Wall Bulging Research Articles

The Deep Inferior Epigastric Perforator Flap for Breast Reconstruction in Overweight and Obese Patients

The authors retrospectively reviewed the computerized records of 71 women undergoing 80 deep inferior epigastric perforator (DIEP) flap reconstructions after mastectomy over a 1-year period. There were 33 normal, 26 overweight, and 12 obese patients. No statistically significant difference in flap complications was found between groups. Overall fat necrosis rates were 11.4 percent for the normal-weight patients, 6.7 percent for the overweight patients, and 6.7 percent for the obese patients. Postoperative hospital time was similar for all groups. The occurrence of abdominal wall fascial laxity was uncommon and similar for all groups. Large (>900 g) reconstructions were completed without prohibitive complications in the reconstruction flap. The DIEP flap represents a significant advance in autologous breast tissue reconstruction. Although concerns regarding fat necrosis rates in DIEP flaps have been voiced, the authors did not see an increasing rate of fat necrosis in their overweight and obese patients, and their overall rate of fat necrosis is comparable to rates reported for free transverse rectus abdominis myocutaneous (TRAM) flaps. Also, increasing body mass index did not seem to affect the rate of delayed complications of the abdominal wall, such as abdominal wall hernia or bulging. Although it was not statistically significant, the authors did observe a trend toward increased wound-healing complications with increasing body mass index. Their data also support the claim that the complete sparing of the rectus abdominis muscles afforded by the DIEP flap avoids abdominal wall fascial bulging or defects often seen in obese TRAM reconstruction patients. Because flap and wound complication rates are similar or superior to those of other autologous tissue reconstruction techniques and the occurrence of abdominal wall defects is all but eliminated, the DIEP flap likely represents the preferred autologous breast reconstruction technique for overweight and obese patients.

The use of ES-MS/MASS Spectrometry to Identify and Compare the Major Non-Polar Lipids in Normal and Dry Eye Tears

Background. – Actomyosin ATPase is one of the major ATP consuming enzymes in the myocardium. We tested whether 2,3-butanedione monoxime (BDM), a reversible inhibitor of actomyosin ATPase, given before coronary occlusion, limits infarct size in anesthetized open-chest dogs.Methods and results. – After circumflex artery catheterization using fluoroscopic guidance, BDM (125 mM) or buffer vehicle was infused (12.0 ml/min) for 20 min (BDM-20, n = 5 and Buffer-20, n = 6) or for 5 min (BDM-5, n = 6 and Buffer-5, n = 6) prior to 60 min of ischemia and 3 h of reperfusion. BDM administration increased subendocardial blood flow 271% above baseline flow (radioactive microspheres), and systolic wall thickening was converted to wall bulging (wall thickening by sonomicrometry was –27 ± 29% and –22 ± 13% of baseline in BDM-20 and BDM-5, respectively). Adjusted mean infarct size (% area-at-risk) was 11.0 ± 2.8% and 11.9 ± 2.6% in BDM-20 and BDM-5 vs. 20.2 ± 2.5% and 20.5 ± 2.5% in Buffer-20 and Buffer-5 (ancova, P < 0.05 for each BDM vs. Buffer group). Measurement of glycolytic metabolites and the adenine nucleotide pool of myocardium paced electronically at 150 beats per minute during total ischemia at 37 °C following BDM showed a metabolic response similar to that seen in ischemic preconditioning. ATP depletion, nucleoside production, and lactate accumulation were slowed in ischemic tissue treated with BDM.Conclusion. – BDM given before the onset of ischemia markedly limited infarct size and reduced energy demand after the onset of ischemia. The explanation for the reduced infarct size induced by BDM treatment is hypothesized to be the persistent reduction in energy demand found in ischemic BDM treated myocardium.

The Actin Cytoskeleton and its Effectors Mediate Multiple Steps in Secretory Vesicle Exocytosis in Rabbit Lacrimal Acinar Epithelial Cells

Background. – Actomyosin ATPase is one of the major ATP consuming enzymes in the myocardium. We tested whether 2,3-butanedione monoxime (BDM), a reversible inhibitor of actomyosin ATPase, given before coronary occlusion, limits infarct size in anesthetized open-chest dogs.Methods and results. – After circumflex artery catheterization using fluoroscopic guidance, BDM (125 mM) or buffer vehicle was infused (12.0 ml/min) for 20 min (BDM-20, n = 5 and Buffer-20, n = 6) or for 5 min (BDM-5, n = 6 and Buffer-5, n = 6) prior to 60 min of ischemia and 3 h of reperfusion. BDM administration increased subendocardial blood flow 271% above baseline flow (radioactive microspheres), and systolic wall thickening was converted to wall bulging (wall thickening by sonomicrometry was –27 ± 29% and –22 ± 13% of baseline in BDM-20 and BDM-5, respectively). Adjusted mean infarct size (% area-at-risk) was 11.0 ± 2.8% and 11.9 ± 2.6% in BDM-20 and BDM-5 vs. 20.2 ± 2.5% and 20.5 ± 2.5% in Buffer-20 and Buffer-5 (ancova, P < 0.05 for each BDM vs. Buffer group). Measurement of glycolytic metabolites and the adenine nucleotide pool of myocardium paced electronically at 150 beats per minute during total ischemia at 37 °C following BDM showed a metabolic response similar to that seen in ischemic preconditioning. ATP depletion, nucleoside production, and lactate accumulation were slowed in ischemic tissue treated with BDM.Conclusion. – BDM given before the onset of ischemia markedly limited infarct size and reduced energy demand after the onset of ischemia. The explanation for the reduced infarct size induced by BDM treatment is hypothesized to be the persistent reduction in energy demand found in ischemic BDM treated myocardium.

Magnetic resonance imaging of cavernous sinus invasion by pituitary adenoma diagnostic criteria and surgical findings.

This study used MRI to define preoperative imaging criteria for cavernous sinus invasion (CSI) by pituitary adenoma (PA). MR images of 103 patients with PA submitted to surgery (48 with CSI) were retrospectively reviewed. The following MR signs were studied and compared to intraoperative findings (the latter were considered the gold standard for CSI detection): presence of normal pituitary gland between the adenoma and CS, status of the CS venous compartments, CS size, CS lateral wall bulging, displacement of the intracavernous internal carotid artery (ICA) by adenoma, grade of parasellar extension (Knosp-Steiner classification) and percentage of intracavernous ICA encased by the tumor. Statistical analysis was performed using qui-square testing and sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were obtained for each MR finding. The following signs have been found to represent accurate criteria for non-invasion of the CS: 1- normal pituitary gland interposed between the adenoma and the CS (PPV, 100%); 2- intact medial venous compartment (PPV, 100%); 3- percentage of encasement of the intracavernous ICA lower than 25% (NPV, 100%) and 4- medial intercarotid line not crossed by the tumor (NPV, 100%). Criteria for CSI were: 1- percentage of encasement of the intracavernous ICA higher than 45%; 2- occlusion of three or more CS venous compartments and 3- occlusion of the CS lateral venous compartment. The CS was very likely to be invaded if the inferior venous compartment was not detected (PPV. 92,8%), if the lateral intercarotid line was crossed (PPV. 96,1%) or if a bulging lateral dural wall of the CS was seen (PPV, 92,3%). The preoperative diagnosis of CSI by PA is extremely important since endocrinological remission is rarely obtained after microsurgery alone in patients with invasive tumors. The above mentioned MR imaging criteria may be useful in advising most of the patients preoperatively on the potential need for complimentary therapy after surgery.

The mechanism of magnetic relaxation in Fe-based nanocrystalline alloy ribbons investigated by permeability spectroscopy

In the present work, in order to elucidate the mechanism of magnetic relaxation in Fe-based nanocrystalline alloy ribbons at low fields and low frequencies, the dependence of the dynamic magnetization properties of nanocrystalline alloy ribbons on the thickness of ribbons has been investigated by permeability spectroscopy. The agreement of the experimental results with the domain wall motion equations confirms that domain wall bulging between the pinning edges is the dominant magnetization mechanism at low fields and low frequencies.

Dependence of the permeability-frequency spectra of Fe88Zr7B4Cu alloys on dc magnetic fields

Effects of applied dc transverse and longitudinal magnetic fields on the dynamic magnetization of Nanoperm alloys are studied by using permeability spectroscopy. It is observed that the permeability-frequency spectra of Nanoperm alloys are very sensitive to the dc transverse magnetic fields. The applied dc transverse magnetic fields may strengthen the domain wall pinning, making the permeability decrease and the relaxation frequency move toward higher frequency. The dc longitudinal magnetic fields have no significant influence on the permeability-frequency spectra. The contribution to initial permeability only results from the bulging of the domain walls parallel to the applied ac magnetic field. The effect of the Earth’s magnetic field on the dynamic magnetic properties of Nanoperm alloys must be considered in actual application.

Giant magnetoimpedance and inductance spectroscopy

A brief review of the giant magnetoimpedance (GMI) phenomenon is presented, including the general definition and phenomenology. The change from impedance modulus to complex inductance is presented, which allows a clearer view of the physics involved. A separation of the magnetization processes is indicated on the basis of the frequency range: low frequencies include spin rotation and domain wall bulging ( f<1 MHz), and only spin rotation for higher frequencies. Experimental results encompassing a wide frequency range, and the effects of torsion strains are presented. The use of inductance spectroscopy therefore leads to a better understanding of GMI.

Effects of Co substitution for Fe on the magnetization process of nanocrystalline Fe–Nb–B alloys

The effects of Co substitution on the magnetization process of nanocrystalline Fe–Nb–B alloys have been investigated by complex permeability spectroscopy in a frequency range from 1 Hz to 1.8 GHz. It is found that substitution of Co results in a magnetic hardening marked by a drop in initial permeability μ i and a rise in relaxation frequency f 0. The deterioration of soft magnetic property is accelerated with the increase of the extent of Co substitution. This is attributed to more pinning sites of domain walls in the material which is produced after the substitution of Co. Under various AC magnetic fields, domain wall motion is the main mechanism in the magnetization process. Permeability spectra reveal that domain wall motion includes domain wall bulging and domain wall displacement.

Experimental and theoretical investigation of compression of a cylinder using a rotating platen

A rig was constructed to carry out compression of an aluminum cylinder with a monotonically rotating platen. The tests carried out showed that the compression load decreased and the side wall bulge severity reduced when the die was rotated. Not all the work supplied by the rotating dies was transferred to the work-piece; circumferential slippage was frequently observed at the die/material interface. This slippage was quantified by comparing measurements made during interrupted testing with the angular velocity of the die. A compound velocity field based on an exponential cusp description of the barreling was employed in an upper bound analysis. An approximate analytical solution was obtained for the degree of barreling and the compression pressure. The model is able to reproduce the decrease in barreling and compression loads with increasing die rotation.

Low frequency magnetoimpedance for Co-based amorphous microwires

In this work, we present a study of the low frequency (5–13 MHz) magnetoimpedance response of amorphous microwires covered by glass. The domain wall magnetization processes active within this frequency range, namely reversible bulging of domain walls and hysteresis, are characterized through the complex inductance formalism, which allows the calculation of Cole–Cole plots. The characteristic semicircle formation of reversible bulging was observed and compared with a theoretical one based on a domain wall model for ferromagnetic wires, resulting in an excellent agreement. In addition, the wire’s magnetoimpedance response was found to be strongly dependent on the application of torsion strain as a consequence of a higher wire’s-induced anisotropy.

Effect of slight surface oxidation on the dynamic magnetization of nanocrystalline FeNbBCu ribbons

In the present work, the effect of slight surface oxidation on the dynamic magnetization of nanocrystalline Fe 82Nb 7B 10Cu 1 ribbons is researched with the method of the complex permeability spectra ( μ∗= μ′− iμ″) in the frequency range from 1 kHz to 1 MHz. It is shown that slight surface oxidation causes the increase of the relaxation frequency. The μ′– H relations indicate the slight increase of the pinning field of the sample after oxidation. Based on the domain wall bulging model, discussion shows that it is the change of the distance between pinning edges before and after oxidation that causes the change of dynamic magnetization properties.

Protection of ischemic myocardium in dogs using intracoronary 2,3-butanedione monoxime (BDM)

Background. – Actomyosin ATPase is one of the major ATP consuming enzymes in the myocardium. We tested whether 2,3-butanedione monoxime (BDM), a reversible inhibitor of actomyosin ATPase, given before coronary occlusion, limits infarct size in anesthetized open-chest dogs. Methods and results. – After circumflex artery catheterization using fluoroscopic guidance, BDM (125 mM) or buffer vehicle was infused (12.0 ml/min) for 20 min (BDM-20, n = 5 and Buffer-20, n = 6) or for 5 min (BDM-5, n = 6 and Buffer-5, n = 6) prior to 60 min of ischemia and 3 h of reperfusion. BDM administration increased subendocardial blood flow 271% above baseline flow (radioactive microspheres), and systolic wall thickening was converted to wall bulging (wall thickening by sonomicrometry was –27 ± 29% and –22 ± 13% of baseline in BDM-20 and BDM-5, respectively). Adjusted mean infarct size (% area-at-risk) was 11.0 ± 2.8% and 11.9 ± 2.6% in BDM-20 and BDM-5 vs. 20.2 ± 2.5% and 20.5 ± 2.5% in Buffer-20 and Buffer-5 (ancova, P < 0.05 for each BDM vs. Buffer group). Measurement of glycolytic metabolites and the adenine nucleotide pool of myocardium paced electronically at 150 beats per minute during total ischemia at 37 °C following BDM showed a metabolic response similar to that seen in ischemic preconditioning. ATP depletion, nucleoside production, and lactate accumulation were slowed in ischemic tissue treated with BDM. Conclusion. – BDM given before the onset of ischemia markedly limited infarct size and reduced energy demand after the onset of ischemia. The explanation for the reduced infarct size induced by BDM treatment is hypothesized to be the persistent reduction in energy demand found in ischemic BDM treated myocardium.

Distortion of Rectangular Tubes in Stretch Bending

During stretch bending, considerable in-plane distortion occurs when a thin-walled rectangular tube is plastically bent. To minimize the distortion, fixed walls are used to limit the bulging of the side walls of the tube. Internal pressure can also be used to compensate for distortion. In this paper, analytical expressions for the amount of distortion and the needed internal pressure are derived based on energy minimization. The theory is in fairly good agreement with experiments.

The analysis of magnetoimpedance by equivalent circuits

Simple circuits formed by resistors, inductors and capacitors can be used to model giant magnetoimpedance (GMI) with a good approximation. Three different circuits are found to represent GMI in the whole frequency range (100 Hz–9 GHz) and the AC magnetic field amplitude range (0.01–7.22 A/m RMS): a series R s C s L s, a parallel R p L p and a parallel R H L H, associated with the magnetization processes of spin rotation (leading to ferro-magnetic spin resonance), domain wall bulging (initial permeability) and domain wall displacement (magnetic hysteresis), respectively. We also propose a correlation between these elements and physical parameters of the sample, such as permeabilities, domain wall damping parameters and domain wall effective mass.

Magnetization process in NANOPERM-type nanocrystalline alloy

The magnetization process in nanocrystalline Fe 85.1Mo 0.5Zr 3.3Nb 3.3B 6.8Cu 1 alloy was studied by varying the AC and/or DC magnetic field amplitude in the frequency range from 0.1 kHz to 1 MHz. When a small magnetic field is applied, the magnetization process is dominated by the domain wall bulging; and when the applied field is over the threshold field ( H p), the magnetization process is dominated by the domain wall bulging and displacement. A small longitudinally DC magnetic field will lead to an increase in the magnetization process, a high DC field produces a decrease in the magnetization process.

Transdiaphragmatic intercostal hernia following a penetrating thoracoabdominal injury: report of a case.

Intercostal hernias with abdominal viscera have rarely been reported following penetrating accidental or surgical trauma. We report herein a case of a traumatic rupture of the left hemidiaphragm, presenting as an intercostal hernia 2 years after a penetrating thoracoabdominal injury. The diaphragmatic rupture had been initially very small and could not be detected in the serial chest films and abdominal computed tomographic scans. The injury was also missed during an exploratory lateral thoracotomy. The patient was admitted with the chief complaint of a painful and gradually enlarging left-sided chest wall bulge of 8 months' duration. Surgery via an anterolateral thoracotomy along the axis of the intercostal hernia was performed, and the omentum and splenic flexura of the colon were reduced.

Correlation between magnetization processes and giant magnetoimpedance response in CoFeBSi amorphous CoFeBSi wires

Giant magnetoimpedance (GMI) in amorphous (Fe 0.06Co 0.94) 72.5B 15Si 12.5 wires (submitted to an alternative current, i ac) has a dependence of the impedance response, Z, on direct current magnetic field, H dc. In as-cast wires, the ac current frequency changes the GMI: for frequencies of a few kHz, the impedance response is a function of H dc, having a single maximum at H dc=0; for frequencies>1 MHz, however, two maxima (with a minimum at H dc=0) are observed. By analyzing the frequency dependence of real, L r, and imaginary inductance, L i (proportional to real and imaginary permeability, respectively), we show that these results can be explained in terms of the dominant magnetization process: domain wall bulging for low frequencies, and magnetization rotation for high frequencies. Plots of both L r and L i as a function of frequency indicate relaxation processes at about 45 kHz, due to a change from domain wall to spin rotation as the dominant magnetization process.

Low-frequency magnetoimpedance: domain wall magnetization processes

A systematic study of the magnetization processes underpinning the giant magnetoimpedance phenomenon at low frequencies ( f<10 MHz) is presented. Instead of observing only the total impedance as the main parameter, in this paper we make use of the complex permeability formalism, by calculating permeabilities from complex impedance results. We first investigate the effects of the ac magnetic field amplitude (as produced by the ac current flowing through the sample). Results point to domain wall bulging as the dominant magnetization process for low ac field amplitude. As this amplitude increases, domain walls are unpinned and displaced, leading to hysteresis. As frequency increases, a clear relaxation behavior is observed. The effects of the dc field are then studied. This parameter produces a damping of domain wall processes, leading to a serious decrease in permeability. Very high frequencies are also considered ( f in the GHz range) from results recently published, which lead to a complete image of all the magnetization processes, since these results clearly show spin rotation and resonance.

Effects of torsion on the magnetoimpedance response of CoFeBSi amorphous wires

CoFeBSi amorphous wires prepared by the in-rotating-water quenching technique were submitted to torsion annealings by Joule heating. Their impedance response, Z, was measured in the giant magnetoimpedance arrangement in the 5 Hz–13 MHz frequency range and 0.2–22 mA AC current amplitude. By comparison with as-cast wires of the same composition, a decrease in Z and an increase in the field irreversibility (at 1 MHz and 2 mA) were observed when submitted to axial DC magnetic fields of ±40 Oe. The analysis of the real and imaginary components of inductance at f<500 kHz allowed the resolution of domain wall bulging from domain wall displacement. As compared with as-cast wires, torsion annealing produced a decrease in both processes. These results are consistently interpreted in terms of an induced magnetic anisotropy.

Impedance Spectroscopy in Ferromagnetic Materials

AbstractImpedance spectroscopy (IS) is a powerful characterization methodology for a wide range of electric materials such as ceramics, ferroelectrics, ion conductors, piezoelectrics, etc. In this paper, an extension of IS to the case of ferromagnetic materials is presented. In particular, the resolution of the most common magnetization processes (domain wall bulging, domain wall displacement and spin rotation) is analyzed. IS is applied to ferrites and giant magnetoimpedance in amorphous wires.