Electric Impedance

Mechanical ventilatory parameters guided by the low flow pressure-volume curve in patients with acute lung injury/ acute respiratory distress syndrome Background: Mechanical ventilation may contribute to lung injury and then enhance systemic inflammation. Optimal ventilatory parameters such as tidal volume (V T ) and positive end expiratory pressure (PEEP) can be determined using different methods. Low flow pressure volume (P/V-LF) curve is a useful tool to assess the respiratory system mechanics and set ventilatory parameters. Aim: To set V T and PEEP according P/V-LF curve analysis and evaluate its effects on gas exchange and hemodynamic parameters. Materials and methods: Twenty seven patients underwent P/V-LF within the first 72 hours of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). P/ V-LF curves were obtained from the ventilator and both lower and upper inflexion points determined. Gas exchange and hemodynamic parameters were measured before and after modifying ventilator settings guided by P/V-LF curves. Results: Ventilatory parameters set according P/V-LF curve, led to a rise of PEEP and reduction of V T : 11.6±2.8 to 14.1±2.1 cm H 2 O, and 9.7±2.4 to 8.8±2.2 mL/kg (p <0.01). Arterial to inspired oxygen fraction ratio increased from 158.0±66 to 188.5±68.5 (p <0.01), and oxygenation index was reduced, 13.7±8.2 to 12.3±7.2 (p <0.05). Cardiac output and oxygen delivery index (IDO 2 ) were not modified. Demographic data, gas exchange improvement and respiratory system mechanics showed no significant difference between patients with extra-pulmonary and pulmonary ALI/ARDS. There was no evidence of significant adverse events related with this technique. Conclusion: P/V-LF curves information allowed us to adjust ventilatory parameters and optimize gas exchange without detrimental effects on oxygen delivery in mechanically ventilated ALI/ ARDS patients (Rev Méd Chile 2007; 135: 307-16).

Background/purposeSkin tissue dielectric constant (TDC) measurements at 300 MHz provide non‐invasive data on free and bound tissue water. TDC‐data is available for some body sites, but most is for female forearm. Contrastingly, there are no data on face‐skin or comparative data between genders. Our goals were to obtain facial‐TDC reference values and determine if TDC‐values differ between genders.MethodsTDC was measured at forehead, cheek, and forearm in 60 young adults (30 men) to a 1.5‐mm depth. Measured TDC‐values were compared with TDC‐values calculated using skin‐thickness data.ResultsMeasured TDC‐values ranged from 39.6 ± 2.9 at male‐forehead to 28.2 ± 2.4 at female forearm and were significantly different (P &lt; 0.001) among each site in the order forehead &gt; cheek &gt;forearm. Male TDC‐values were greater than female TDC‐values (P &lt; 0.01) with differences from 5.6% at forehead to 11.3% at forearm. Calculated TDC‐values incorporating site and gender skin‐thickness diffe...

Previous studies have shown that differing qualities of blood specimen seem to influence whole blood electrical aggregometry (WBEA), making it difficult to standardize the method. The aim of this study was to investigate the impact of hematocrit (HCT) and platelet count (PLC) on in vitro platelet aggregation in titrated whole blood (CWB) in order to compensate for their possible effects on impedance aggregometry. Red blood cells and blood platelets were isolated from fresh titrated whole blood taken from 15 healthy donors (mean age = 26 years) and recombined to 20 physiologically relevant combinations of hematocrit and platelet count (HCT: 20-50, PLC: 100-500). Platelet aggregability was measured using WBEA with three different triggers. A special-purpose software package was used in this study, ensuring proper calibration, acquisition, and evaluation of analogue to digital converted data, allowing the calculation of a set of characteristic parameters of each impedance curve. Most of the linear regressions showed that all parameters significantly depend on HCT and PLC. Furthermore, we found interactions of both variables, making it impossible to focus on the effects of one of the investigated variables only. The outcome of this study is a set of dependences, allowing the calculation of regressions for in vitro aggregation in whole blood, enabling a comparison of blood of any quality with each other, regardless of the variables HCT and PLC. Together with the previously defined dependence of sample age on WBEA data, this step should help to make this technique a more reliable and practicable clinical tool, making it suitable for daily routine investigations.

Inhalation of organic dusts within agriculture environments contributes to the development and/or severity of airway diseases, including asthma and chronic bronchitis. MyD88 KO (knockout) mice are nearly completely protected against the inflammatory and bronchoconstriction effects induced by acute organic dust extract (ODE) treatments. However, the contribution of MyD88 in lung epithelial cell responses remains unclear. In the present study, we first addressed whether ODE-induced changes in epithelial cell responses were MyD88-dependent by quantitating ciliary beat frequency and cell migration following wounding by electric cell-substrate impedance sensing. We demonstrate that the normative ciliary beat slowing response to ODE is delayed in MyD88 KO tracheal epithelial cells as compared to wild type (WT) control. Similarly, the normative ODE-induced slowing of cell migration in response to wound repair was aberrant in MyD88 KO cells. Next, we created MyD88 bone marrow chimera mice to investigate the relative contribution of MyD88-dependent signaling in lung resident (predominately epithelial cells) versus hematopoietic cells. Importantly, we demonstrate that ODE-induced airway hyperresponsiveness is MyD88-dependent in lung resident cells, whereas MyD88 action in hematopoietic cells is mainly responsible for ODE-induced TNF-α release. MyD88 signaling in lung resident and hematopoietic cells are necessary for ODE-induced IL-6 and neutrophil chemoattractant (CXCL1 and CXCL2) release and neutrophil influx. Collectively, these findings underscore an important role for MyD88 in lung resident cells for regulating ciliary motility, wound repair and inflammatory responses to ODE, and moreover, show that airway hyperresponsiveness appears uncoupled from airway inflammatory consequences to organic dust challenge in terms of MyD88 involvement.

In hemodialysis patients extracellular fluid overload is a predictor of all-cause and cardiovascular mortality, and a relation with inflammation has been reported in previous studies. The magnitude and nature of this interaction and the effects of moderate fluid overload and extracellular fluid depletion on survival are still unclear. We present the results of an international cohort study in 8883 hemodialysis patients from the European MONDO initiative database where, during a three-month baseline period, fluid status was assessed using bioimpedance and inflammation by C-reactive protein. All-cause mortality was recorded during 12 months of follow up. In a second analysis a three-month baseline period was added to the first baseline period, and changes in fluid and inflammation status were related to all-cause mortality during six-month follow up. Both pre-dialysis estimated fluid overload and fluid depletion were associated with an increased mortality, already apparent at moderate...

Background: Infertility and hormonal alterations can be associated with cancer and venous thrombosis. Varicocele and ovarian varicose veins are related to infertility and venous thrombosis. The objective is to investigate the association between cancer and venous thrombosis with varicose veins beside the germinating glands. Methods: 152 patients were selected from my private practice in a retrospective observational study, 98 of them having been diagnosed with venous thrombosis and 54 of them having been diagnosed with cancer. The diagnosis of ovarian varicose veins and varicocele were made through eco-color-Doppler, considering the minimum diameter of the veins (4.0; 5.0 and 6.0 mm) next to the ovaries and next to the testicles (2.0; 2.5 and 3.0 mm), with a reflux of 0.5 s. Of a total of 14,800 patient, 152 with cancer and profound venous thrombosis were selected (1, 02%). Among these patients 98 were venous thrombosis cases and 54 were cancer cases. When we adopted the minimum diameter in varicocele as 2.0 mm, 2.5 mm and 3.0 mm, the rate was of 96.7%, 83.6% & 55.7% respectively and in ovarian varicose veins as 4.0 mm, 5.0 mm and 6.0 mm, the rate was of 83.5%, 61.5% and 39.6%. Varicose veins next to the testicles and the ovaries are associated to oxidative stress, which can interfere in the hypothalamic-pituitary-gonadal axis, in the immune system and in genetics. The high prevalence of varicose veins next to the germinating glands may play a determinant role in cancer and in venous thrombosis.

Background: Handheld bioelectrical impedance analysis (BIA) devices estimate body fat but often yield inconsistent results between Regular and Athlete modes. Objective: This study evaluates a simple averaging technique to improve accuracy. Methods: A Monte Carlo simulation with 1,000 samples was conducted using predefined error ranges: +2% to +6% for Regular Mode and-4% to-1% for Athlete Mode. Results were compared to a gold-standard body fat value of 18%, and mean absolute error (MAE) was calculated for each method. Results: The averaging method produced a MAE of 0.87%, outperforming both Regular (3.96%) and Athlete (2.48%) modes individually. Conclusions: Averaging Regular and Athlete Mode readings improves the accuracy of consumer BIA devices. This simple method offers an immediate, no-cost improvement for fitness users.

The pH-sensing receptor ovarian cancer G protein-coupled receptor 1 (OGR1; GPR68) is expressed in the gut. Inflammatory bowel disease is typically associated with a decrease in local pH, which may lead to altered epithelial barrier function and subsequent gastrointestinal repair involving epithelial cell adhesion and migration. As the mechanisms underlying the response to pH changes are not well understood, we have investigated OGR1-mediated, pH-dependent signaling pathways in intestinal epithelial cells. Caco-2 cells stably overexpressing OGR1 were created and validated as tools to study OGR1 signaling. Barrier function, migration, and proliferation were measured using electric cellsubstrate impedance-sensing technology. Localization of the tight junction proteins zonula occludens protein 1 and occludin and the rearrangement of cytoskeletal actin were examined by confocal microscopy. Paracellular permeability and protein and gene expression analysis using DNA microarrays were performed on filter-grown Caco-2 monolayers. We report that an acidic pH shift from pH 7.8 to 6.6 improved barrier function and stimulated reorganization of filamentous actin with prominent basal stress fiber formation. Cell migration and proliferation during in vitro wound healing were inhibited. Gene expression analysis revealed significant upregulation of genes related to cytoskeleton remodeling, cell adhesion, and growth factor signaling. We conclude that acidic extracellular pH can have a signaling function and impact the physiology of intestinal epithelial cells. The deconstruction of OGR1-dependent signaling may aid our understanding of mucosal inflammation mechanisms.

The pH-sensing receptor ovarian cancer G protein-coupled receptor 1 (OGR1; GPR68) is expressed in the gut. Inflammatory bowel disease is typically associated with a decrease in local pH, which may lead to altered epithelial barrier function and subsequent gastrointestinal repair involving epithelial cell adhesion and migration. As the mechanisms underlying the response to pH changes are not well understood, we have investigated OGR1-mediated, pH-dependent signaling pathways in intestinal epithelial cells. Caco-2 cells stably overexpressing OGR1 were created and validated as tools to study OGR1 signaling. Barrier function, migration, and proliferation were measured using electric cell-substrate impedance-sensing technology. Localization of the tight junction proteins zonula occludens protein 1 and occludin and the rearrangement of cytoskeletal actin were examined by confocal microscopy. Paracellular permeability and protein and gene expression analysis using DNA microarrays were perf...

Oil palm empty fruit bunch fibre and high density polyethylene (OPEFB-HDPE) composites have been used in a variety of applications. However, it’s potentials as a lossy low dielectric substrate for microwaves applications has not been realized. To date, the application of biomaterials as fillers in composites for microwave applications have not been examined. Research on lossy low dielectric constant materials reported are limited to polymer and metal oxides composite which are much expensive, hence the need to study materials from organic source which are less expensive, biodegradable and abundantly available. This thesis presents the development of a lossy, low dielectric constant substrate based on OPEFB-HDPE composites for various microwave applications such as LTCC based patch antenna. This antenna require low dielectric constant and high loss factor factor (ε′ between 2.5 and 10.0, ε′′ ranges from 0.1 to 0.4). (ε′ between 2.5 and 10.0, ε′′ ranges from 0.1 to 0.4). OPEFB exhibit...

Variability of peak flow measurements has been related to clinical outcomes in asthma. We hypothesised that the entropy, or information content, of airway impedance over short time scales may predict asthma exacerbation frequency. 66 patients with severe asthma and 30 healthy control subjects underwent impulse oscillometry at baseline and following bronchodilator administration. On each occasion, airway impedance parameters were measured at 0.2-s intervals for 150 s, yielding a time series that was then subjected to sample entropy (SampEn) analysis. Airway impedance and SampEn of impedance were increased in asthmatic patients compared with healthy controls. In a logistic regression model, SampEn of the resistance at 5 Hz minus the resistance at 20 Hz, a marker of the fluctuation of the heterogeneity of airway constriction over time, was the variable most strongly associated with the frequent exacerbation phenotype (OR 3.23 for every 0.1 increase in SampEn). Increased airway impedance and SampEn of impedance are associated with the frequent exacerbation phenotype. Prospective studies are required to assess their predictive value.

The bioimpedance spectroscopic (BIS) analytical algorithm described in this report allows for the non-invasive measurement of intravascular, interstitial, and intracellular volume changes during various fluid management procedures. The purpose of this study was to test clinical use feasibility and to demonstrate the validity of the BIS algorithm in computing compartmental volume shifts in human subjects undergoing fluid management treatment. Validation was performed using volume changes recorded from 20 end stage renal disease (ESRD) patients. The validation procedure involved mathematically deriving post hoc hematocrit profiles from the BIS data-generated fluid redistribution time profiles. These derived hematocrit profiles were then compared to serial hematocrit values measured simultaneously by a CritLine® monitor during 60 routine hemodialysis (HD) sessions. Regression and Bland Altman analyses confirm that the BIS algorithm can be used to reliably derive the continuous and real time rates of change of the compartmental fluid volumes. Regression results yielded a R 2 > 0.99 between the two measures of hematocrit at different times during dialysis. The slopes of the regression equations at the different times were nearly identical, demonstrating an almost one to one correspondence between the BIS and CritLine® hematocrits. Bland Altman analyses show that the BIS algorithm can be used interchangeably with the CritLine® monitor for the measurement of hematocrit. The present study demonstrates for the first time that BIS can provide real-time continuous measurements of compartmental intravascular, interstitial and intracellular fluid volume changes during fluid management procedures when used in conjunction with this new algorithm.

Efficient driving of piezoelectric materials is desirable when operating transducers for biomedical applications such as high intensity focused ultrasound (HIFU) or ultrasound imaging. More efficient operation reduces the electric power required to produce the desired bioeffect or contrast. Our preliminary work [Cole et al. Journal of Physics: Condensed Matter. 2014;26(13):135901.] suggested that driving transducers by applying orthogonal electric fields can significantly reduce the coercivity that opposes ferroelectric switching. We present here the experimental validation of this biaxial driving technique using piezoelectric ceramics typically used in HIFU. A set of narrow-band transducers was fabricated with two sets of electrodes placed in an orthogonal configuration (following the propagation and the lateral mode). The geometry of the ceramic was chosen to have a resonance frequency similar for the propagation and the lateral mode. The average (± s.d.) resonance frequency of the samples was 465.1 (± 1.5) kHz. Experiments were conducted in which each pair of electrodes was driven independently and measurements of effective acoustic power were obtained using the radiation force method. The efficiency (acoustic/electric power) of the biaxial driving method was compared to the results obtained when driving the ceramic using electrodes placed only in the pole direction. Our results indicate that the biaxial method increases efficiency from 50% to 125% relative to the using a single electric field.

This paper presents a practical implementation of an integrated MRI-compatible CMOS amplifier capable of directly driving a piezoelectric ultrasound transducer suitable for high-intensity focused ultrasound (HIFU) therapy. The amplifier operates in Class DE mode without the need for an output matching network. The integrated amplifier has been implemented with the AMS AG H35 CMOS process. A class DE amplifier design methodology for driving unmatched piezoelectric loads is presented along with simulation and experimental results. The proposed design achieves approximately 90% efficiency with over 800 mW of output power at 1010 kHz. The total die area including pads is 2 mm 2 . Compatibility with MRI was validated with B1 imaging of a phantom and the amplifier circuit.

Efficient driving of piezoelectric materials is desirable when operating transducers for biomedical applications such as high intensity focused ultrasound (HIFU) or ultrasound imaging. More efficient operation reduces the electric power required to produce the desired bioeffect or contrast. Our preliminary work [Cole et al. Journal of Physics: Condensed Matter. 2014;26(13):135901.] suggested that driving transducers by applying orthogonal electric fields can significantly reduce the coercivity that opposes ferroelectric switching. We present here the experimental validation of this biaxial driving technique using piezoelectric ceramics typically used in HIFU. A set of narrow-band transducers was fabricated with two sets of electrodes placed in an orthogonal configuration (following the propagation and the lateral mode). The geometry of the ceramic was chosen to have a resonance frequency similar for the propagation and the lateral mode. The average (± s.d.) resonance frequency of the samples was 465.1 (± 1.5) kHz. Experiments were conducted in which each pair of electrodes was driven independently and measurements of effective acoustic power were obtained using the radiation force method. The efficiency (acoustic/electric power) of the biaxial driving method was compared to the results obtained when driving the ceramic using electrodes placed only in the pole direction. Our results indicate that the biaxial method increases efficiency from 50% to 125% relative to the using a single electric field.

Purpose The incidence of GER, related symptoms and complications in patients treated for congenital diaphragmatic hernia (CDH) are poorly defined. The aim was to evaluate incidence and development of GER in children treated for CDH in a short-and long-term follow-up period, identifying potential risk factors of morbidity. Methods Thirty-six patients were evaluated with pH-MII at a median age of 6 months (T1) and re-evaluated with pH-MII and endoscopy at a median age of 5 years (T2). Results The incidence of reflux was 83 % in T1 and 61 % in T2; the incidence of symptoms was 62 % in T1 and 38 % in T2. In both groups the reflux was mainly nonacidic. Patch, intrathoracic stomach and esophageal dysmotility were risk factors for GER. The incidence of GER and symptoms decrease over the time but it was higher than in the literature, probably because it is mainly non-acidic and evaluable only with MII. The esophageal dysmotility was found to be the main risk factor. An high incidence of reflux and esophagitis was found also in asymptomatic patients, and so a close follow-up is recommended in all patients even if it is asymptomatic.

Summary The purpose of this study was to investigate whether changes in the right ventricular end-diastolic and end-systolic volume, and consequently of the stroke volume, can be detected by a DC-coupled intracardiac impedance signal. Measurements were conducted in 13 patients with an implanted Inos pacemaker, testing various measurement configurations. Volume changes were induced by incremental overpacing and by postural changes. The pulse contour systolic integral from the peripheral blood pressure was used as a marker of stroke volume changes. Four out of seven patients with quadrupolar impedance measurement configurations showed a good correlation between the stroke impedance and the pulse contour systolic integral (r 2 : 0.51 – 1.0) with the expected slope sign. All six patients tested with different tri-, bi-, or unipolar configurations had a good correlation (r 2 : 0.73 –0.96) with a correct slope. Similar results were obtained for the Starling regression, stroke impedance vs...

Three electrostatic transduction methods are analyzed for a micromechanical, longitudinal mode, beam resonator. The conventional parallel plate transducer placed at the location of maximum displacement is compared to two solid, dielectric transducers internal to the resonator. Although the solid dielectric offers higher permittivity than the free-space-filled transducers, the unfavorable locations of the internal transducers reduce or even remove the performance advantage of the higher permittivity.

Influenza A viruses cause annual epidemics and occasional pandemics that spread worldwide. The nucleoprotein is essential for the survival of this virus and is thus well-conserved. We developed a quantitative electronic biosensor displaying a protein recognition thanks to the covalent grafting of anti-nucleoprotein antibodies. The detection device lies on interdigitated array microelectrodes (IDAM), covered with alumina (Al 2 O 3 ) to protect the underlying aluminum and enhance the electrical coupling. As the dimensions of the IDAM can determine the sensitivity of the sensor, we processed 4 structures with varying electrode widths and spacings in the same silicon chip and assessed their individual performance. The sensing area of each sensor is 200*200 µm 2 and the overall chip-size is 3*3 mm 2 . The sensor is mounted in a DIL-16-package partially encapsulated by resin.

Ischemia and reperfusion (I/R) injury is a major cause of hepatic failure after liver surgery, but no method could monitor or predict it real-time during surgery. We measured bioelectrical impedance (BEI) and cell viability to assess the usefulness of BEI during I/R in rat liver. A 70% partial liver ischemia model was used. BEI was measured at various frequencies. Adenosine triphosphate (ATP) content, and palmitic acid oxidation rate were measured, and histological changes were observed in order to quantify liver cell viability. BEI changed significantly during ischemia at low frequency. In the ischemia group, BEI increased gradually during 60 min of ischemia and had a tendency to plateau thereafter. The ATP content decreased below 20% of the baseline level. In the I/R group, BEI recovered to near baseline level. After 24 hr of reperfusion, the ATP contents decreased to below 50% in 30, 60 and 120 min of ischemia and the palmitic acid metabolic rates decreased to 91%, 78%, and 74%, ...

Invasive urothelial carcinomas of the bladder (UCB) characteristically show a loss of differentiation markers. The transcription factor Grainyhead-like 3 (GRHL3) plays an important role in the development and differentiation of normal urothelium. The contribution to UCB progression is still elusive. Differential expression of GRHL3 was assessed in normal human urothelium and in non-invasive and invasive bladder cancer cell lines. The contribution of GRHL3 to cell proliferation, viability and invasion in UCB cell lines was determined by gain- and loss-of-function assays in vitro and in an organ culture model using de-epithelialized porcine bladders. GRHL3 expression was detectable in normal human urothelial cells and showed significantly higher mRNA and protein levels in well-differentiated, non-invasive RT4 urothelial carcinoma cells compared to moderately differentiated RT112 cells. GRHL3 expression was absent in anaplastic and invasive T24 cells. Ectopic de novo expression of GRHL...

Acute lung injury represents the result of multiple pathways initiated by local or systemic insults and is characterized by profound vascular permeability, pulmonary edema, and life-threatening respiratory failure. Permeability-reducing therapies are of potential clinical utility but are currently unavailable. We hypothesized that polyethylene glycol (PEG) compounds, inert and non-toxic polymers that serve as a surrogate mucin lining in intestinal epithelium, may attenuate agonistmediated lung endothelial cell (EC) barrier dysfunction. High molecular weight PEG (PEG15-20) produced rapid, dose-dependent increases in transendothelial electrical resistance (TER) in human lung endothelium cultured on gold microelectrodes, reflecting increased paracellular integrity. The maximal effective concentration of 8% PEG induced a sustained 125% increase in TER (40 hrs), results similar to barrier-enhancing agonists such as sphingosine 1-phosphate (40% increase in TER). Maximal PEG barrier enhancement was achieved at 45-60 min and PEG effectively reversed both thrombin-and LPS-induced EC barrier dysfunction. Consistent with the increase in TER, immunofluorescent studies demonstrated that PEG produced significant cytoskeletal rearrangement with formation of well-defined cortical actin rings and lamellipodia containing the actin-binding proteins, cortactin and MLCK, known participants in cell-matrix and cell-cell junctional adhesion. Finally, PEG challenge induced rapid alterations in levels of MAP kinase and MLC phosphorylation. In summary, PEG joins a number of EC barrier-regulatory agents which rapidly activate barrier-enhancing signal transduction pathways which target the cytoskeleton and provides a potential therapeutic strategy in inflammatory lung injury.

Myosin ID (MYO1D) is a member of the class I myosin family. We screened 48,649 third generation (G3) germline mutant mice derived from N-ethyl-N-nitrosourea-mutagenized grandsires for intestinal homeostasis abnormalities after oral administration of dextran sodium sulfate (DSS). We found and validated mutations in as a cause of increased susceptibility to DSS-induced colitis. MYO1D is produced in the intestinal epithelium, and the colitis phenotype is dependent on the nonhematopoietic compartment of the mouse. Moreover, MYO1D appears to couple cytoskeletal elements to lipid in an ATP-dependent manner. These findings demonstrate that MYO1D is needed to maintain epithelial integrity and protect against DSS-induced colitis.

The Valsalva maneuver is frequently used to test autonomic function. Previous work demonstrated that the blood pressure decrease during the Valsalva maneuver relates to thoracic hypovolemia, which may preclude pressure recovery during phase II, even with normal resting peripheral vasoconstriction. We hypothesized that increased regional blood volume, specifically splanchnic hypervolemia, accounts for the degree of thoracic hypovolemia during the Valsalva maneuver. We studied 17 healthy volunteers aged 15–22 yr. All had normal blood volumes by dye dilution. Subjects also had normal vascular resistance while supine as well as normal vasoconstrictor responses during 35° upright tilt. We assessed changes in estimated splanchnic, pelvic-thigh, and lower leg blood volume, along with thoracic blood volume shifts, by impedance plethysmography before and during the Valsalva maneuver performed in the supine position. Early increases in splanchnic blood volume dominated the regional vascular c...

Background: Lean body mass (LM) plays an important role in mobility and metabolic function. We previously identified five loci associated with LM adjusted for fat mass in kilograms. Such an adjustment may reduce the power to identify genetic signals having an association with both lean mass and fat mass. Objectives: To determine the impact of different fat mass adjustments on genetic architecture of LM and identify additional LM loci. Methods: We performed genome-wide association analyses for whole-body LM (20 cohorts of European ancestry with n = 38,292) measured using dual-energy X-ray absorptiometry) or bioelectrical impedance analysis, adjusted for sex, age, age 2 , and height with or without fat mass adjustments (Model 1 no fat adjustment; Model Conclusions: In conclusion, we identified one novel LM locus (TNRC6B). Our results suggest that a genetically determined increase in lean mass might exert either harmful or protective effects on metabolic traits, depending on its relation to fat mass.

To calculate the values of the phase angle of septic patients using bioelectrical impedance analysis, correlate the values with clinical and biochemical variables, and compare them to reference values. Methods: Cohort study conducted with 50 septic patients aged ≥18 years old, admitted to intensive care units, and assessed according to prognostic indexes (APACHE II and SOFA), clinical progression (mortality, severity of sepsis, length of stay in intensive care unit), biochemical parameters (albumin and C-reactive protein), and the phase angle. Results: The average age of the sample was 65.6±16.5 years. Most patients were male (58%) and suffering from septic shock (60%). The average APACHE II and SOFA scores were 22.98±7.1 and 7.5±3.4, respectively. The patients who survived stayed nine days on average (five to 13

Objective: To study temperature distribution in different electrodes and to evaluate thermal spread during colonic anastomosis induced by radiofrequency energy through finite element modeling, aiming to provide the basis for optimizing the design of new electrodes with improved effectiveness of electrosurgical welding. Methods: Three electrodes with the feature of concave-convex (CC), rail coupled concave-convex (rail-CC), and cross rail coupled concave-convex (cross rail-CC) were designed for radiofrequency-induced serosa-to-serosa colonic anastomoses to evaluate the thermal spread process by finite element modeling using COMSOL Multiphysics. Parameters used in the modeling were set with a peak voltage of 45 V, a duty cycle of 10% and a repetition rate of 1 s. Additionally, a three-dimensional finite element model of the cross rail-CC electrode was further constructed to compare temperature variation and distribution when the voltage Fwas applied to ridges of upper electrode alternately. Results: The electrode with CC design produced similar temperature between 'gap' and 'compressed' areas, whereas the electrode with rail-CC design exhibited the highest temperature at 'gap' and 'compressed' areas compared with those with CC and cross rail-CC designs. Moreover, the cross rail-CC electrode, by tightly occluding the upper and lower electrodes, could create uniform compression and temperature variation. When electric voltage was applied to ridges of upper electrode of the cross rail-CC electrode alternately, the temperature at 'gap' was half of that at the 'compressed' section, which was comparable to the temperature at 'compressed' area in the rail-CC electrode (p=0.241). Conclusion: Alternating application of voltage to ridges of upper electrode of the cross rail-CC electrode can potentially produce an optimal fusion zone by reducing thermal damage with low 'gap' temperature while keeping the 'compressed' temperature high.

Background: Nutrition is an integral part of patient care and malnutrition is highly prevalent in End Stage Liver Disease (ESLD) patients. In order to incorporate nutrition therapy as a crucial component of long-term care liver transplantation (LT) treatment, there must be substantial evidence associating malnutrition with clinical characteristics. Methods: Sixty-Nine recipients undergoing living donor LT in Max Super Specialty Hospital, Saket were recruited in the study. Based on subjective global assessment (SGA), they were grouped as normal, moderate, and severely malnourished. Information regarding patient's medical history, biochemical parameters (Hemoglobin, albumin and bilirubin) was collected. Energy and protein intake was computed using 24-hour dietary recall and handgrip strength (HGS) was assessed using hand grip dynamometer. Results: The data revealed that most of the patients were males (95%) with an average age of 48.96±10.36 years. It was reported that 63.7% patients also had several comorbidities. As per SGA, 85.50% of patients were severely malnourished. Majority of the patients had poor hand grip strength (95%) and lower albumin levels of <3.5 g/dL. The data showed significantly lower hemoglobin levels, muscle strength (sarcopenia) and higher grades of ascites among malnourished individuals (p<0.05). It was depicted that malnourished patients had significantly higher blood loss and PRBC usage during surgery (p<0.05). The data also showed significantly lower intake of energy and protein among patients before transplantation. Conclusion: An essential step in the treatment of ESLD is assessing nutritional status. The current study demonstrated higher grade of malnutrition among pre-LT patients. The significant association between malnutrition and the clinical parameters such as tense ascites, sarcopenia and higher blood product usage and blood loss during surgery, highlights the need for the creation of nutrition-related interventional treatments for pre-LT patients.

Electrical synapses continuously transfer signals bi-directionally from one cell to another, directly or indirectly via intermediate cells. Electrical synapses are common in many brain structures such as the inferior olive, the subcoeruleus nucleus and the neocortex, between neurons and between glial cells. In the cortex, interneurons have been shown to be electrically coupled and proposed to participate in large, continuous cortical syncytia, as opposed to smaller spatial domains of electrically coupled cells. However, to explore the significance of these findings it is imperative to map the electrical synaptic microcircuits, in analogy with in vitro studies on monosynaptic and disynaptic chemical coupling. Since "walking" from cell to cell over large distances with a glass pipette is challenging, microinjection of (fluorescent) dyes diffusing through gap-junctions remains so far the only method available to decipher such microcircuits even though technical limitations exist. Based on circuit theory, we derive analytical descriptions of the AC electrical coupling in networks of isopotential cells. We then suggest an operative electrophysiological protocol to distinguish between direct electrical connections and connections involving one or more intermediate cells. This method allows inferring the number of intermediate cells, generalizing the conventional coupling coefficient, which provides limited information. We validate our method through computer simulations, theoretical and numerical methods and electrophysiological paired recordings.

Pseudomonas (P. ) aeruginosa is a major opportunistic pathogen especially in immunocompromised patients. To evaluate the invasiveness of respiratory pathogens, we developed monolayer culture systems and examined the degree of invasion by P. aeruginosa and invasive Salmonella (S. ) typhimurium strains using human respiratory cell lines: A549 (derived from lung cancer), BEAS-2B (normal bronchial epithelium), and Calu-3 (pleural effusion of a patient with adenocarcinoma of the lung). Cells were seeded into filter units containing 0.33 cm 2 filter membranes with 3.0 µ m pores, and were incubated at 37°C under 5% CO 2 for 4-10 days. By monitoring the trans-monolayer electrical resistance (TER), we judged that BEAS-2B cells (TER values: 436.2 ± 16.8 to 628.8 ± 66.3 Ω cm 2 ) and Calu-3 cells (TER values: 490.5 ± 25.2 to 547.8 ± 21.6 Ω cm 2 ) formed monolayers with tight junctions, but not A549 cells. On day 8 of culture, monolayer cultures were infected with bacteria, and the number of microorganisms penetrating into the basolateral medium was counted. Wild-type P. aeruginosa PAO1 (PAO1 WT) and S. typhimurium SL1344 were detected in the basolateral medium of BEAS-2B monolayer system by 3 h after inoculation, while only P. aeruginosa PAO1 WT was detected in the basolateral medium of Calu-3 monolayer, indicating poor invasiveness of S. typhimurium SL1344 in the Calu-3 system. These findings suggest that BEAS-2B or Calu-3 monolayer system could be useful for evaluating the invasiveness of respiratory pathogens. Because of the difference in bacterial invasiveness, we may need to choose a suitable cell system for each target pathogen.

Hyperphosphatemia can lead to detrimental effects such as cardiovascular calcification, renal osteodystrophy, secondary hyperparathyroidism, and increased mortality. The neutrophil-to-lymphocyte ratio (NLR) in chronic kidney disease (CKD) patients provides information on the inflammation status, used as a marker of poor prognosis in several disorders such as malignancies, CKD, and myocardial infarction. To study the impact of hyperphosphatemia on NLR and on the inflammatory state in patients with stage 5 CKD under maintenance hemodialysis. This observational cross-sectional study was carried out in Benha University Hospitals on 100 patients on maintenance hemodialysis who were recruited and subjected to careful history, clinical examination, and NLR; serum phosphorus was done with different inflammatory markers. Patients who had significant infection, malignancy, and who had undergone parathyroidectomy were excluded. The mean±SD age of the studied group was 61.28±13.7, 40% were males. There were two (2%) with hypophosphatemia, 44 (44%) with normal phosphate, 34 (34%) with mild hyperphosphatemia, and 20 (20%) with severe hyperphosphatemia. There was high statistically significant difference between categories of serum phosphate as regards white blood cell, neutrophil, NLR, and platelets. There was high statistically significant difference between categories of serum phosphate as regards erythrocyte sedimentation rate and C-reactive protein (CRP), and statistically significant difference as regards serum albumin and serum intactparathyroid hormone. There was positive significant correlation between serum phosphorus and both CRP and NLR (P<0.001). There is high prevalence of hyperphosphatemia in hemodialysis patients. Hyperphosphatemia was associated with higher intact-parathyroid hormone, white blood cell, neutrophil, NLR, CRP, and platelets.

Many neuron types exhibit preferred frequency responses in their voltage amplitude (resonance) or phase shift to subthreshold oscillatory currents, but the effect of biophysical parameters on these properties is not well understood. We propose a general framework to analyze the role of different ionic currents and their interactions in shaping the properties of impedance amplitude and phase in linearized biophysical models and demonstrate this approach in a two-dimensional linear model with two effective conductances g L and g 1 . We compute the key attributes of impedance and phase (resonance frequency and amplitude, zero-phase-frequency, selectivity, etc.) in the g L -g 1 parameter space. Using these attribute diagrams we identify two basic mechanisms for the generation of resonance: an increase in the resonance amplitude as g 1 increases while the overall impedance is decreased, and an increase in the maximal impedance, without any change in the input resistance, as the ionic current time constant increases. We use the attribute diagrams to analyze resonance and phase of the linearization of two biophysical models that include resonant (I h or slow potassium) and amplifying currents (persistent sodium). In the absence of amplifying currents, the two models behave similarly as the conductances of the resonant currents is increased whereas, with the amplifying current present, the two models have qualitatively opposite responses. This work provides a general method for decoding the effect of biophysical parameters on linear membrane resonance and phase by tracking trajectories, parametrized by the relevant biophysical parameter, in pre-constructed attribute diagrams.

Purpose: The aim of this research is to model the effect of methylation on hydrogen bonding ability, surface area, polar surface area, volume, lipophilicity, charge, and cross-sectional diameters of a series of mono-, di-, and tri- methyl substituted analogs of arginine-glycine-aspartic acid (RGD) and compare these parameters to in vitro transport properties across Caco-2 monolayers. Methods: Molecular modeling was used to investigate the structural parameters that may influence the transport properties of RGD and its methyl analogs at pH 7.4. Log P was experimentally determined using a potentiometric method and compared to cLogP. Transport studies were carried out using Caco-2 cell monolayers. Results: Parameters such as polar and total surface area, volume, and Log P were found to vary with both the number and the sites of methyl substitution on the RGD molecule. The calculated as well as the experimental Log P values were found to be less than minus 2. The calculated maximum cross-sectional diameters ranged from 9 to 12 A. No detectable transport was noted. Conclusions: Results of our study indicate that in the design considerations for the development of new peptidomimetic RGD analogs with enhanced oral bioavailability, an important parameter to consider is the three dimensional conformation of the peptides which influences their hydrogen bonding ability, polarity and molecular geometry.

The aim of this research is to model the effect of methylation on hydrogen bonding ability, surface area, polar surface area, volume, lipophilicity, charge, and cross-sectional diameters of a series of mono-, di-, and tri- methyl substituted analogs of arginine-glycine-aspartic acid (RGD) and compare these parameters to in vitro transport properties across Caco-2 monolayers. Molecular modeling was used to investigate the structural parameters that may influence the transport properties of RGD and its methyl analogs at pH 7.4. Log P was experimentally determined using a potentiometric method and compared to cLogP. Transport studies were carried out using Caco-2 cell monolayers. Parameters such as polar and total surface area, volume, and Log P were found to vary with both the number and the sites of methyl substitution on the RGD molecule. The calculated as well as the experimental Log P values were found to be less than minus 2. The calculated maximum cross-sectional diameters range...

The American Physical Society Dielectric properties of bent-core nematic materials 1 PETER SALAMON, NANDOR EBER, SAMUEL SPRUNT, JAMES GLEESON, ANTAL JAKLI -We report of dielectric spectroscopy measurements on bent-core nematic liquid crystals. The components of the relative dielectric permittivity and the dielectric loss have been measured as functions of frequency and temperature in the case of various bent-core mesogens in their nematic and isotropic phases. The results show that these liquid crystals have extraordinary dielectric behaviors if we compare them to the traditional calamitic materials, such as -they show low frequency ( < 10 kHz ) relaxations. Distortion elastic constants measurements reveal that K 1 / K 3 ∼ 1 in contrast to typical calamitics. The reasons for these anomalous behaviors will be discussed.

Introduction: Electrical impedance myography (EIM) is a non-invasive, painless, objective technique to quantify muscle pathology. Methods: We measured EIM in 8 arm and leg muscles in 61 boys with Duchenne muscular dystrophy (DMD) and 31 healthy boys, ages 3-12 years, at 5 centers. We determined the reliability of EIM and compared results in boys with DMD to controls and to 6-minute walk distance (6MWD), North Star Ambulatory Assessment (NSAA), timed functional tests (TFTs), and strength (hand-held dynamometry). Results: EIM was well tolerated and had good inter-and intrarater reliability (intraclass correlation coefficient 0.81-0.96). The averaged EIM phase value from all muscles was higher (P < 0.001) in controls (10.45 6 2.29) than boys with DMD (7.31 6 2.23), and correlated (P 0.001) with 6MWD (r 5 0.55), NSAA (r 5 0.66), TFTs (r 5 -0.56), and strength (r 5 0.44). Conclusion: EIM is a reliable and valid measure of disease severity in DMD. Longitudinal studies comparing EIM with other assessments over time in DMD are warranted.

The importance of the inspection process has been magnified by the requirements of the modern manufacturing environment. In elec tronics mass-production manufacturing facilities, an attempt is often made to achieve 100 % quality assurance of all parts, subassemblies, and finished goods. A variety of approaches for automated visual inspection of printed circuits have been reported over the last two decades. In this survey, algorithms and techniques for the automated inspection of printed circuit boards are examined. A classification tree for these algorithms is presented and the algorithms are grouped according to this classification. This survey concentrates mainly on image analysis and fault detection strategies, these also include the state-of-the-art techniques. Finally, limitations of current inspection systems are summarized.

Breathing moves volumes of electrically insulating air into and out of the lungs, producing conductivity changes which can be seen by electrical impedance tomography (EIT). It has thus been apparent, since early EIT research, that imaging of ventilation could become a key clinical application of EIT. In this paper, we review the current state and future prospects for lung EIT, by a synthesis of the presentations of the authors at the "special lung sessions" of the annual biomedical EIT conferences in 2009-2011. We argue that lung EIT research has arrived at an important transition. It is now clear that valid and reproducible physiological information is available from EIT lung images. We must now ask the question: how can these data be used to help improve patient outcomes? To answer this question, we develop a classification of possible clinical scenarios in which EIT could play an important role, and we identify clinical and experimental research programs and engineering developments required to turn EIT into a clinical useful tool for lung monitoring.

Full bibliographic details must be given when referring to, or quoting from full items including the author's name, the title of the work, publication details where relevant (place, publisher, date), pagination, and for theses or dissertations the awarding institution, the degree type awarded, and the date of the award.

Preliminary clinical evidence suggests that Helicobacter pylori may be associated with diarrhea through its vacuolating toxin (VacA). To establish whether VacA induces intestinal secretion, epithelial damage, or both, purified pH-activated VacA was added to Caco-2 cell monolayers mounted in Ussing chambers, and electrical parameters were monitored. Mucosal addition of VacA induced an increase in short circuit current, consistent with enterotoxic effect. The effect was time-and dose-dependent and saturable. It was not found if the toxin was not pH-activated, added to the serosal side, or preheated. In cells preloaded with the Ca2 ϩ buffering compound BAPTA/AM or with the Cl Ϫ channel inhibitor 5-nitro-2-3-(3phenylpropylamino)benzoic acid, short circuit current did not change, indicating that VacA induces activation of Ca2 ϩ -dependent Cl Ϫ channels. VacA did not show cytopathic effects, as judged by tissue resistance. These results support the hypothesis that H. pylori may be associated with diarrhea through production of VacA.

Background and aim: Gastric banding induced considerable and rapid weight loss in morbid obesity. Nevertheless data on changes in body composition following gastric banding are scanty. In this study, we evaluated the 2-year changes in body composition in a small group of morbidly obese women treated by laparoscopic adjustable gastric banding (LAGB) associated with a well balanced low-calorie diet. Methods and results: We studied 20 premenopausal morbid obese women with BMI ranging from 35 to 57 (kg/m 2 ) before, and 6, 12 and 24 months after laparoscopic adjustable gastric banding (LAGB). A well balanced 5.4 MJ/day hypocaloric diet was prescribed after surgery. Total body water (TBW), fat-free mass (FFM) and fat mass (FM) were investigated using conventional bioelectrical impedance analysis (BIA). Tissue hydration was also assessed by impedance vector analysis and the RXc graph method. The subjects showed a total weight loss of 28% of baseline body weight. In the first 6 months after surgery, patients lost 18.5G5.9 kg of body weight (17.6G6.2 kg of FM and 0.7G1.4 kg of FFM). From 6 to 12 months, a further 12.5G7.5 kg of body weight was lost (10.5G8.2 kg of FM and 2.2G3.8 kg of FFM). During the last 12 months, weight loss was 3.0G2.3 kg (1.9G3.7 kg of FM and 1.1G2.9 kg of FFM). The weight loss observed after LAGB was mainly due to a decrease in FM, whereas TBW, FFM and BCM were only slightly and non-significantly reduced. No changes in body hydration status were observed after surgery.

Background and aim: Gastric banding induced considerable and rapid weight loss in morbid obesity. Nevertheless data on changes in body composition following gastric banding are scanty. In this study, we evaluated the 2-year changes in body composition in a small group of morbidly obese women treated by laparoscopic adjustable gastric banding (LAGB) associated with a well balanced low-calorie diet. Methods and results: We studied 20 premenopausal morbid obese women with BMI ranging from 35 to 57 (kg/m 2 ) before, and 6, 12 and 24 months after laparoscopic adjustable gastric banding (LAGB). A well balanced 5.4 MJ/day hypocaloric diet was prescribed after surgery. Total body water (TBW), fat-free mass (FFM) and fat mass (FM) were investigated using conventional bioelectrical impedance analysis (BIA). Tissue hydration was also assessed by impedance vector analysis and the RXc graph method. The subjects showed a total weight loss of 28% of baseline body weight. In the first 6 months after surgery, patients lost 18.5G5.9 kg of body weight (17.6G6.2 kg of FM and 0.7G1.4 kg of FFM). From 6 to 12 months, a further 12.5G7.5 kg of body weight was lost (10.5G8.2 kg of FM and 2.2G3.8 kg of FFM). During the last 12 months, weight loss was 3.0G2.3 kg (1.9G3.7 kg of FM and 1.1G2.9 kg of FFM). The weight loss observed after LAGB was mainly due to a decrease in FM, whereas TBW, FFM and BCM were only slightly and non-significantly reduced. No changes in body hydration status were observed after surgery.