PA Size Research Articles

Influence of hydrodynamic shear stress on activated algae granulation process for wastewater treatment

In this study, activated algae granule was formed by cultivating a mixed culture of the microalga Chlorella vulgaris and activated sludge in batch photobioreactors (PBRs). Without aeration, the granulation process was investigated through four different agitation speeds of 80, 120, 160, 200 rpm (shear stress of 0.04, 0.15, 0.35, 0.69 Pa). Hydrodynamic shear stress created by agitation affected the activated algae granulation through microeddies. The largest granule was achieved in the PBR with agitation speed of 200 rpm (R200) with shear stress of 0.69 Pa (size of 339 µm). In the other hand, lower shear stress in R160 (shear stress of 0.35 Pa) gave optimal results in terms of wastewater treatment efficiency and granule formation time (165 days of operation). Shear stress below 0.15 Pa (120 rpm) showed no granule formation during 220 days operation. While shear stress from 0.04–0.15 Pa could guarantee mass transfer for the entire co-culture without aeration, shear stress from 0.15–0.69 Pa was a suitable range for the granulation process of activated algae. This study reveals that activated algae granule formation through agitation mechanism is a promissing solution for wastewater treatment and microalgae biomass recovery to substantially increase the share of renewable energy in the global energy mix.

Abstract 16351: Reference Equations for Pulmonary Artery Size and Pulsatility Using Echocardiography in Pulmonary Arterial Hypertension

Background: A main pulmonary artery (MPA) diameter>25 mm on echocardiography is supportive of the diagnosis of pulmonary hypertension according to the most recent European Society of Cardiology guideline. [1]. The size of the pulmonary artery may however vary according to body size, age and sex and these considerations may be important for diagnostic purposes. Objectives: (1) to derive reference equations for MPA and right pulmonary artery (RPA) size on echocardiography that consider the effect of body size, age and sex; (2) to determine which measure of PA size better classifies pulmonary arterial hypertension (PAH) when compared to controls. Method: 248 healthy males and females were recruited as part of Stanford aging study and 200 patients with PAH have been retrospectively included from the Stanford Adult PH Program. The diameters of the MPA and RPA were measured from the parasternal short axis. The RPA diameter, area, and pulsatility index were measured from the supra sternal notch view. MedCalc Version 20.2018 statistical software program was used for modeling and assessing the variance function. Results: Multivariate regression analysis was used to derive PA size reference equations that consider sex, age, and height. Age retained in all the models and height was the second most influential variable. Using a Z score threshold of 1.96, for the diastolic MPA diameter size yielded an area under the ROC curve (AUC) of 0.91, 87.15% sensitivity and 95.19% specificity to detect PAH. In comparison, the AUC for absolute MPA size >25 mm during diastole and systole yields 0.87 and 0.67, respectively which was significantly different from the z score AUC (Figure-1). Conclusion: Our study develops echocardiography reference equations for PA size accounting for the influence of age, height, and sex that can potentially refine PAH diagnostic algorithms if further validated.

Thyrotropin-secreting pituitary adenomas: clinical features and results of treatment in 45 patients

Thyrotropin-secreting pituitary adenomas (TSH-PA) are a rare cause of thyrotoxicosis and account for 0.5-2% of all pituitary adenomas. Taking into account the rarity of the disease, it is extremely important to analyze each case of TSH-PA. To analyze the clinical characteristics and treatment outcomes of patients with TSH-PA, as well as to determine preoperative and early postoperative factors that predict long-term remission. In a single-center retrospective study we analyzed clinical signs, laboratory and instrumental studies, as well as the treatment outcomes of patients with TSH-PA from 2010 to 2023. Preoperative factors, as well as TSH level measured on day 3 postoperatively, were evaluated for their ability to predict long-term remission when comparing groups of patients with and without remission. The study included 45 patients with TSH-PA (14 men, 31 women), with a median age of 45 years [30; 57]. The most common clinical manifestations of TSH-PA were: cardiac arrhythmia in 37 (82.2%) patients, thyroid pathology in 27 (60%), neurological disorders in 24 (53.35%). Most PAs were macroadenomas (n=35, 77.8%). Preoperatively, 28 (77.8%) patients received somatostatin analogs, and 20 (71.4%) patients were euthyroid at the time of surgery. Surgical treatment was performed in 36 (80%) patients, postoperative remission was achieved in 31 cases (86.1%). Administration of somatostatin analogues to patients with no remission/relapse after surgery lead to the remission in 100% of cases (4/4). A 1 mm increase in PA size raised the odds of recurrence/no remission by 1.15-fold,and PA invasion during surgery - by 5.129 fold. A TSH level on day 3 postoperatively above 0.391 mIU/L (AUC, 0.952; 95% CI 0.873-1.000; standard error 0.04; p<0.001) identifies patients with relapse/absence of remission after surgical treatment (sensitivity = 100%, specificity = 88.9%). The TSH-PA in the structure of PAs is extremely rare, and as a result, most of them are misdiagnosed and detected already at the stage of macroadenoma. The most effective method of treatment is transnasal transsphenoidal adenomectomy. Somatostatin analogues can be used as second-line therapy if surgical treatment is ineffective. We have proposed a possible model for postoperative TSH levels (>0.391 mU/l) to predict recurrence of TSH-PA, which requires validation on an expanded number of cases.

A Statistical Analysis for Optimisation of a Hybrid BBDB-PA in Mantanani Island, Sabah

The hybrid form of wave energy converter (WEC) is a recent advancement in research concerning harvesting energy from the ocean. This study investigates the effect of size and position of the point absorber integrated with a backward bent duct buoy. The aim of this optimisation is to maximise the WEC-absorbed power and heave response amplitude operators (RAO) at a specific sea site. The optimisation process was applied based on the data collected over a one-year period about sea characteristics for a nearshore region of the Mantanani Island. We present a methodology for optimising the Hybrid BBDB-PA based on a statistical analysis and the hydrodynamics of the system in the frequency and time domain. We used the ANSYS/AQWA software for the hydrodynamic diffraction analysis, and the design of experiments method was applied through the statistical software to determine the optimised parameters. We found that the diameter and gap length between PA and BBDB were found to significantly influence two characteristics, namely, heave RAO and maximum power absorption of PA. This observation shows that the PA size was directly proportional to the performance because a higher diameter has more contact with the ocean’s wet surface area with the ocean and absorbed higher wave energy. Moreover, the gap length between the PA and BBDB was directly correlated with a wavelength, which followed the theoretical value for peak-to-trough length, where the maximum wave height occurs. Despite the condition parameter, we discovered that the WEC position and arrangement were responsible for the highest value of the power, regardless of the PA position used in the experiment. The results of this research provide recommendations for optimising the ocean energy harvesting in order to fully utilise ocean space for energy.

Risk factors for Pseudomonas aeruginosa airway infection and lung function decline in children with cystic fibrosis

Background Cystic fibrosis (CF) lung disease is characterised by recurrent Pseudomonas aeruginosa (Pa) infections, leading to structural lung damage and decreased survival. The epidemiology of Pa infection and its impact on lung function in people with CF (pwCF), especially in recent birth cohorts, remain uncertain.Methods We included 1,231 French pwCF under 18 years of age. Age at initial acquisition (Pa-IA), chronic colonisation (Pa-CC), and duration from Pa-IA to Pa-CC were estimated using the Kaplan–Meier method. Demographic, clinical, and genetic characteristics were analysed as risk factors for Pa infection using Cox regression models. Lung function decline was assessed by modelling percent-predicted forced expiratory volume in 1 s (ppFEV1) before Pa infection, after Pa-IA, and after Pa-CC.Results Among the 1,231 pwCF, 50% had Pa-IA by the age of 5.1 years [95% confidence interval (CI) 3.8–6.2] and 25% had Pa-CC by the age of 14.7 years (95% CI 12.1 to ∞). We observed that CF-related diabetes and liver disease were risk factors for Pa, while gender, CFTR variants, and CF centre size were not. Genetic variants of TNF, DCTN4, SLC9A3, and CAV2 were confirmed to be associated with Pa. The annual rate of ppFEV1 decline before Pa was -0.38% predicted/year (95% CI -0.59 to -0.18), which decreased significantly after Pa-IA to -0.93% predicted/year (95% CI -1.14 to -0.71) and after Pa-CC to -1.51% predicted/year (95% CI -1.86 to -1.16).Conclusions We identified and replicated several risk factors associated with Pa infection and showed its deleterious impact on lung function in young pwCF. This large-scale study confirmed that Pa airway infection is a major determinant of lung disease severity.

Using RV/LV ratio and cardiac biomarkers to define the risk of mortality from pulmonary embolism.

Acute pulmonary thromboembolism (PTE) is a common cause of cardiovascular mortality. Right ventricular (RV) dysfunction is the most important cause of mortality. Computed Tomography Pulmonary Angiography (CTPA) can detect right ventricular enlargement which is an indicator of RV dysfunction at the time of diagnosis. This study aimed to determine the parameters indicating RV dysfunction in CTPA and correlation of early mortality findings. In this retrospective study, electronic files of patients diagnosed PTE with CTPA between January 2012 and December 2017 were evaluated. Measurements of heart chambers, IVC reflux, and IVS morphology were calculated. In-hospital mortality of the patients after acute PTE diagnosis was evaluated. There were 206 eligible patients. Among the evaluated radiological parameters, right atrium (RA) size (p= 0.002), PA size (p= 0.003), Ao size (p= 0.006), and the presence of IVC reflux (p= 0.001) were associated with mortality. No significant relationship was found between RV/LV ≥1 and mortality (p= 0.908). All patients with PTE-related mortality had RV/LV ratio ≥1 in CTPA and had IVC reflux. Patients with an RV/LV ratio of ≥1 had statistically significantly higher troponin levels (p= 0.004) and IVC reflux (p= 0.025) compared to patients with an RV/LV ratio of <1. In conclusion, RV/LV ratio should be evaluated together with cardiac biomarkers to define mortality risk.

PULMONARY ARTERY ANEURYSM- IDIOPATHIC

SUMMARY&#x0D; A 28-years old female presented with complaints of palpitations and mild retrosternal chest pain. CXR showed a prominent Pulmonary artery. A TTE study revealed a huge main pulmonary artery whereas the branches were of normal size. CT angio revealed aneurysmal main Pulmonary artery and normal sized branches. No concomitant etiology was noted, hence labelled as “idiopathic pulmonary artery aneurysm”.&#x0D; CASE DESCRIPTION&#x0D; A 28-year-old female presented with retrosternal chest pain and palpitations for the last six months. Multiple systolic clicks and murmur III/VI heard in the pulmonary area. ECG was unremarkable. Chest X-Ray showed no cardiomegaly and a prominent pulmonary artery. Transthoracic echocardiography showed aneurysmally dilated main pulmonary artery (size: 5.7cm). Pulmonary valve was thickened with mild regurgitation. CT angiogram demonstrated dilated main pulmonary artery (axial dimension: 5.8cm) with normal-sized branches (Figure1). Immunological workup was negative. She was advised surgical intervention which she agreed to pursue soon at a tertiary care hospital near her hometown.&#x0D; LEARNING POINTS&#x0D; &#x0D; Pulmonary artery aneurysm has an incidence of 1 in 14,000, (based on 109,571 autopsies).1&#x0D; The maximum normal diameter of MPA is 29mm in males and 27 mm in females. For interlobar branches the maximum size it 17 mm.2 If the size exceeds 4 cm it is “aneurysmal” which may be true of false.&#x0D; PAA could be congenital due to Eisenmenger’ syndrome, Pulmonary valve stenosis and absent pulmonary valve syndrome. Connective tissue disorders (Marfan’s syndrome, alpha-1 antitrypsin deficiency and Ehlers-Danlos syndrome) and autoimmune disorders (Behcet’s disease and Hughes-Stovin syndrome).3&#x0D; Acquired causes include PAH, auto-immune disease (vasculitis), trauma infections, malignancy and idiopathic.&#x0D; For intervention no consensus of opinion is available. However expert opinion recommends it when the patient becomes symptomatic or pulmonary artery diameter exceeds 5 cm to 6 cm.&#x0D; &#x0D; QUESTIONS WITH ANSWERS&#x0D; &#x0D; Question 1: Is there any difference in the measurement of PA size by echocardiography and CT?&#x0D; Question 2: What is the usual site of dissection in PAA?&#x0D; Question 3: In Pulmonary arterial tree what is the most frequent site of aneurysm?&#x0D; Question 4: Some cases of pulmonary artery aneurysms can be managed medically- Y/N?&#x0D; Question 5: The technique of choice for diagnosing PA aneurysm is pulmonary angiography or CT angiogram?&#x0D; &#x0D; Answers&#x0D; &#x0D; Question 1: Yes&#x0D; Question 2: Main PA&#x0D; Question 3: Right lobar artery&#x0D; Question 4: Yes&#x0D; Question 5: CT angiogram&#x0D; &#x0D; References&#x0D; &#x0D; Deterling RA Jr and Clagett OT. Aneurysm of the pulmonary artery; review of the literature and report of a case. Am Heart J. 1947;34:471-99.&#x0D; Truong QA, Massaro JM, Rogers IS, Mahabadi AA, Kriegel MF, Fox CS. Reference values for normal pulmonary artery dimensions by noncontrast cardiac computed tomography: The Framingham Heart Study. Circ Cardiovasc Imaging 2012;5:147-54.&#x0D; Agarwal S, Chowdhury UK, Saxena A, Ray R, Sharma S, Airan B. Isolated idiopathic pulmonary artery aneurysm. Asian Cardiovasc Thorac Ann. 2002;10(2):167-9.&#x0D;

Pulmonary artery size on computed tomography is associated with major morbidity after pulmonary lobectomy

ObjectiveTo investigate the relationship of pulmonary artery diameter (PAD) measured by computed tomography (CT) with outcomes following lobectomy. MethodsRecords of patients undergoing pulmonary lobectomy for lung cancer between 2011 and 2018 were reviewed. Baseline characteristics and postoperative outcome data were derived from the institutional Society of Thoracic Surgeons database. Luminal diameter of the central pulmonary arteries and ascending aorta were measured on preoperative CTs. Logistic regression analyses were performed to test the association of PAD with complications. ResultsA total of 736 lobectomy patients were included, who had a preoperative CT scan (25% with contrast, 75% noncontrast) available for review. A total of 141 (19.2%) patients had an enlarged main PAD ≥30 mm, and 58 (7.9%) patients had a main PAD that was larger than the ascending aorta (PA/ascending aorta ratio > 1). The right or left PAD on the surgical side was associated with major complication (odds ratio per mm, 1.12; 95% confidence interval, 1.05-1.18; P < .001), unexpected intensive care unit admission (odds ratio per millimeter, 1.11; 95% confidence interval, 1.04-1.19; P = .002), and 30-day mortality (odds ratio per millimeter, 1.25; 95% confidence interval, 1.06-1.46; P = .007). On multivariable analysis, adjusted for cardiovascular comorbidities, pulmonary function, and the operative approach, surgical side PAD remained an independent factor associated with major complication. ConclusionsCT-based measurements of the PAD on the operative side may inform of the about the risk of major complications after lobectomy. Review of PA size on preoperative CT scans may help identify patients who would benefit from formal evaluation of PA pressures to improve the operative risk assessment.

Pulmonary Artery Size in Interstitial Lung Disease and Pulmonary Hypertension: Association with Interstitial Lung Disease Severity and Diagnostic Utility.

PurposeIt is postulated that ILD causes PA dilatation independent of the presence of pulmonary hypertension (PH), so the use of PA size to screen for PH is not recommended. The aims of this study were to investigate the association of PA size with the presence and severity of ILD and to assess the diagnostic accuracy of PA size for detecting PH.MethodsIncident patients referred to a tertiary PH centre underwent baseline thoracic CT, MRI and right heart catheterisation (RHC). Pulmonary artery diameter was measured on CT pulmonary angiography and pulmonary arterial areas on MRI. A thoracic radiologist scored the severity of ILD on CT from 0 to 4, 0 = absent, 1 = 1–25%, 2 = 26–50%, 3 = 51–75%, and 4 = 76–100% extent of involvement. Receiver operating characteristic analysis and linear regression were employed to assess diagnostic accuracy and independent associations of PA size.Results110 had suspected PH due to ILD (age 65 years (SD 13), M:F 37:73) and 379 had suspected PH without ILD (age 64 years (SD 13), M:F 161:218). CT derived main PA diameter was accurate for detection of PH in patients both with and without ILD - AUC 0.873, p =< 0.001, and AUC 0.835, p =< 0.001, respectively, as was MRI diastolic PA area, AUC 0.897, p =< 0.001, and AUC 0.857, p =< 0.001, respectively Significant correlations were identified between mean pulmonary arterial pressure (mPAP) and PA diameter in ILD (r = 0.608, p < 0.001), and non-ILD cohort (r = 0.426, p < 0.001). PA size was independently associated with mPAP (p < 0.001) and BSA (p = 0.001), but not with forced vital capacity % predicted (p = 0.597), Transfer factor of the lungs for carbon monoxide (TLCO) % predicted (p = 0.321) or the presence of ILD on CT (p = 0.905). The severity of ILD was not associated with pulmonary artery dilatation (r = 0.071, p = 0.459).ConclusionsPulmonary arterial pressure elevation leads to pulmonary arterial dilation, which is not independently influenced by the presence or severity of ILD measured by FVC, TLCO, or disease severity on CT. Pulmonary arterial diameter has diagnostic value in patients with or without ILD and suspected PH.

Normal pulmonary artery and branch pulmonary artery sizes in children.

To establish standards for pulmonary artery and branch pulmonary artery (PA and BPA) effective diameter (ED) and cross-sectional area (CSA) by using computed tomography (CT) data in children of a wide range of sizes and investigate the roundness of arteries. The ED (average of short and long axes) and CSA for the PA and BPA were measured using 1-mm collimation double-oblique reconstructions. Ordinary least squares regression was used to investigate models with various functional forms that related ED and CSA to patient size. Aspect ratio (AR), the short axis divided by long axis, was measured to evaluate roundness. The ideal diameter derived from CSA measurements was compared to ED, short axis, and long axis measurements. 108 CT examinations were analyzed in children without reason for abnormal PA size who ranged in age from 0 to 18years (mean, 10.9years; SD, 5.9years). Interrater reliability was excellent. Data were modeled using a natural log-transformed response variable and a linear term for height as the independent variable. AR for the PA, right pulmonary artery, and left pulmonary artery measured < 0.9 for 38, 55, and 37%, respectively, indicating that many arteries are not round. Ideal diameter was not significantly different than ED but was for short- and long-axis diameter measurements. Normal ED and CSA for PA and BPA were determined for children of different sizes. Measurements outside of the normal range are consistent with dilatation or stenosis. Single diameter techniques are likely to introduce error.

Right ventricular global longitudinal strain predicts survival in patients with pulmonary hypertension receiving specific vasodilator therapy

In patients (pts) with pulmonary hypertension (PH) different right ventricular (RV) function parameters predict outcome. Data regarding the prognostic value of averaged 6-segments RV longitudinal strain (RV-GLS) in PH pts are scarce. To assess the predictive value of 6-segments RV-GLS in PH pts receiving vasodilator therapy. Forty-seven pts (40 ± 15 years, 36 women) with PH treated with either bosentan, sildenafil, or both and 33 controls with similar age and gender (40 ± 11 years, 21 women) were studied. Clinical parameters and biologic (B-type natriuretic peptide, BNP), invasive and echocardiographic parameters of RV function (TAPSE, TDI-derived free-RV wall S- and e’-wave, RV fractional area change (FAC), Tei index, I/H, RV isovolumic acceleration-IVA) were assessed. 6-segments RV-GLS was measured from the apical 4-chamber view by STE. PH pts were followed-up for 23 months (2–49). An endpoint of cardiac death was defined. PH pts had larger right chambers size, PA size and pressures, impaired RV function than controls (all P < 0.001), including RV-GLS (−14.0 ± 4.8% vs. −23.3 ± 2.7%, P < 0.001). During follow-up, 8 pts died. At univariable analysis, predictors of death were: TAPSE (15 ± 3 mm in deceased pts vs. 18 ± 3 mm in surviving pts, P = 0.011), RV-S (9.1 ± 2.1 cm/s vs. 11.5 ± 1.9 cm/s, P = 0.002), FAC (25 ± 9% vs. 36 ± 8%, P = 0.001), RV-GLS (−9.6 ± 4.2% vs. −14.9 ± 4.5%, P = 0.003), IVA (0.16 ± 0.07 cm/s 2 vs. 0.24 ± 0.10 cm/s 2 , P = 0.041) and BNP levels (lnBNP, 5.8 ± 1.0 vs. 4.7 ± 1.5, P = 0.05). ROC curve analysis showed that RV-GLS had the highest predictive value for cardiac death (AUC 0.82, P = 0.005). Cutoff value for RV-GLS derived from ROC curve analysis was used to construct Kaplan-Meier survival curves. A value of −13.2% for RV-GLS predicted cardiac death with 87% sensitivity and 62% specificity. In PH pts, RV function parameters have prognostic value. Six-segments RV-GLS emerged as the strongest predictor of cardiac death with a cutoff value of −13.2% in this setting.

Fate of Duct-Dependent, Discontinuous Pulmonary Arteries After Arterial Duct Stenting.

Significant and balanced PA growth following arterial duct (AD) stenting has already been consistently reported in literature. However, to date, no data are available about the role of this approach as palliation of congenital heart disease with a duct-dependent discontinuous pulmonary artery (dPA). The aim of this study was to evaluate the fate of a dPA of ductal origin following trans-catheter AD stabilization. Angiographic PA evaluation was performed in seven patients submitted to neonatal AD stenting as palliative recruitment of dPA. Five patients showed discontinuity of one PA, while two patients had both PAs served by bilateral ducts. PA growth was evaluated as per the Nakata index, McGoon ratio as well as dPA (n=9) versus heart-dependent PA (hPA; n=5) size and z-score changes. AD stabilization was performed using coronary stents dilated to 3.2±0.3mm (median 3.4), with significant increase of O2 saturation (from 83±11 to 95±5%, p<0.02). Control angiography was performed 5.1±2.8months (median 6 months) after duct stenting, showing significant growth of the dPA (from 3.7±1.0 to 7.6±2.7mm, p<0.001; z-score from -0.7±1.4 to 1.7±2.2, p<0.01). A trend toward better growth of the dPA as compared with the hPA was found (117±87 vs. 54±34%, p=NS). The final vessel size was still significantly different between the groups (dPA 7.6±2.7 vs. hPA 11.9±3.4mm, p=0.02), although the final z-score value did not significantly differ (dPA 1.7±2.2 vs. hPA 3.8±0.9mm, p=NS). In conclusion, percutaneous AD stenting is effective in promoting a significant catch-up growth of duct-dependent dPA, being, therefore, advisable as a reliable alternative to surgical palliation.

Synthesis of stiffness‐tunable and cell‐responsive Gelatin–poly(ethylene glycol) hydrogel for three‐dimensional cell encapsulation

Biosynthetic poly(ethylene glycol) (PEG)-based hydrogels have been extensively investigated as extracellular matrix (ECM) mimicking gels as they retain the benefits of both ECM (biological cues) and synthetic hydrogels (tunable mechanical properties). In this article, we developed and characterized a new gelatin-PEG (GP) hydrogel that retains the benefits of gelatin and synthetic hydrogels. In this strategy, the thiolation of gelatin was accomplished by reacting with Traut's reagent; the thiolated gelatin was then conjugated to one end of PEG diacrylate (PEGDA) by Michael-type addition reaction. Two kinds of GP precursors, GP30 and GP60, were synthesized by changing the amount of Traut's reagent, while the weight ratio between thiolated-gelatin and PEGDA of GP30 and GP60 was 1.451:1 and 0.785:1, respectively. Finally, neonatal human dermal fibroblasts were encapsulated into the hydrogel by cross-linking the remaining double bonds of precursor under ultraviolet light. These GP hydrogels can encapsulate the fibroblasts in situ with high cell viability. Moreover, the behaviors of cells within the GP hydrogels can be modulated by varying the cross-linking density of GP hydrogel (storage modulus from 40 to 2000 Pa). In particular, this article showed that a minimum amount of cell-binding motifs (gelatin >2.30 wt/vol % and 44.0% dry weight percentage) are required for attachment; and appropriate initial rheological and structural properties (storage modulus <∼100 Pa and mesh size >∼150 nm) can accelerate the attachment of cells and improve cell viability. Hence, this mixed-hydrogel platform allows an easily control hydrogel structure and modulates cell behavior to reconstruct new tissue in the three-dimensional microenvironments. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2401-2411, 2016.

Abstract 18747: Young Infants With Severe Tetralogy of Fallot: Early Primary Surgery versus Trans-catheter Palliation

Introduction: Infants with severe tetralogy of Fallot (TOF) may undergo: 1) early primary surgical repair (EARLY) or 2) early catheter palliation (CATH) prior to delayed surgical repair. We compared these two strategies to 3) usual elective single stage TOF repair (USUAL). Methods: We studied 453 TOF repairs (2000-2012, excluding BT shunts). USUAL strategy at our institution is repair ≥3 months. Risk adjusted hazard analysis compared freedom from surgical or catheter reintervention. Somatic size, branch PA size and RV systolic pressure were modeled using 2543 echo reports via mixed model regression. Results: Table: group characteristics for USUAL (383), EARLY (42) and CATH (28). CATH involved: RVOT stent=18, RVOT balloon=9, ductal stent=1. Risk adjusted freedom from surgical reoperation was 88%, 87% and 85% for USUAL, EARLY and CATH respectively, at 10 years. EARLY and CATH had similar reoperation rates, except for very young children (&lt;1 month) where EARLY primary repair conferred increased risk of further surgery (Figure). Risk adjusted freedom from catheter reintervention was higher for EARLY (76%) and especially so for CATH (53%) at 10 years, versus USUAL (83%; Figure). Somatic growth and progression of RVSP (37-40mmHg) was similar among groups at 8 years. EARLY (P=.02) and CATH (P=.09) tend to have smaller bPAs initially. The CATH group tend to remain smaller in the long-term, whereas growth in EARLY matches USUAL. Conclusions: Early primary repair at very young ages comes with a cost of increased late surgical reoperation. Early transcatheter palliation tends to come with a cost of increased late transcatheter intervention - possibly related to slower branch PA growth.

Detection and analysis of anodic current transients associated with nanoscale β-phase precipitates on an Al–Mg microelectrode

The metastable pitting of Al–5wt%Mg microelectrode (diameter 50μm) after aging at 150°C for 10h has been investigated under a constant potential in deaerated 0.6M NaCl solution (pH 3.5). Current transients (pA size) associated with the dissolution of nanoscale β-phase precipitates have been detected. Taking the cathodic current of H2 evolution inside the pit into account, the average volume determined from a charge associated with individual current transients is about 39% of those measured by TEM. This result implies that the selective dissolution of Mg in β-phase precipitates (Al3Mg2) may occur during the metastable pitting process.

Midgestation Fetal Pulmonary Annulus Size Is Predictive of Outcome in Tetralogy of Fallot

Surgical management of tetralogy of Fallot (TOF) is increasingly moving toward valve-sparing approaches rather than transannular patch (TAP). We evaluate whether fetal pulmonary valve (PV) size is predictive of postnatal course and surgical approach in TOF. In this retrospective study, fetal and postnatal demographic, clinical, and echocardiographic data on 66 patients diagnosed prenatally with TOF were collected. We compared those with midgestation PV z-score > -3.5 to those with z-score ≤-3.5. We analyzed fetal and postnatal PV size and growth and outcomes between groups Gestational age at first fetal echo was 23 weeks (range 18-28). PV diameter and z-score on midgestation echo were 3.5 mm (1.3-6.0) and -2.8 (-0.5 to -6.0) respectively. Patients with PV z-score ≤ -3.5 on first fetal echo had smaller PV diameter (4.5 vs. 5.0 mm, P = .047) and PV z-score (-3.8 vs. -2.8, P < .001) in late gestation and at time of surgery (6.0 mm vs. 7.0 mm, P = .01; z-score = -2.9 vs. -1.7, P = .007). Similarly, those with smaller fetal PV z-score had smaller main and branch pulmonary arteries at time of surgery. PV growth rate over gestation was similar between groups, while after-birth PV growth rate was lower in those with smaller PV (0 mm/month vs. 0.6 mm/month, P = .002). Those with smaller pulmonary valve were more likely to be cyanotic (P = .05), to undergo surgery at <1 month (P < .01), and to have a TAP repair (P = .01). Among patients undergoing valve-sparing repair, those with smaller PV underwent more reinterventions for residual valvar PS (P < .01). Midgestation fetal PV size is predictive of postnatal PV and PA size in TOF. Midgestation PV size has implications for timing and type of surgical management as well as for need for reintervention in valve-sparing repair patients and is therefore important to consider in prenatal counseling for TOF fetuses.

Shunt Reintervention and Time-Related Events After Norwood Operation: Impact of Shunt Strategy

The use of right ventricle-to-pulmonary artery shunt (RV-PA) is thought to improve postoperative hemodynamics in hypoplastic left heart syndrome (HLHS). Proximal shunt obstruction often prompts early reintervention. Description of our technique and analysis of outcomes after Norwood operation using RV-PA shunt (NRVPA) was undertaken. Between January 2005 and June 2009, 100 consecutive neonates with HLHS underwent stage-1 palliation (S1P). Sixty-five had NRVPA. From 56 survivors, 52 (86. 2%) reached pre-Glenn cardiac catheterization. The RV-PA shunt was constructed using nonringed polytetrafluoroethylene with reversed beveling and hood augmentation of its anterior wall. The PA size, Nakata index, pulmonary to systemic blood flow ratio, and any pre-Glenn intervention were studied. The RV function and NRVPA diastolic reversal flow were assessed. Mean age and weight at S1P were 6. 6 ± 3. 5 days and 3. 21 ± 0. 57 kg, respectively. No shunt reversal flow to RV was noted the first 48 hours after S1P by echocardiogram. No patient had shunt revision after hospital discharge from S1P. Mean age and weight at stage-2 palliation were 14. 9 ± 5. 1weeks and 5. 4 ± 2. 1 kg, respectively. No patient had proximal shunt stenosis. Six patients with distal shunt stenosis and associated central PA hypoplasia (32% ± 17% PA diameter reduction), 3 with left PA and 2 with right PA) stenoses had balloon angioplasty. The pulmonary to systemic blood flow ratio between patients requiring pre-stage-2 palliation intervention and patients without intervention was 1. 05 ± 0. 3 versus 1. 13 ± 0. 37 (p = 0. 09). Right PA and left PA growth was balanced (right PA/left PA 0. 99 ± 0. 3; right PA 26. 8 ± 11. 5 mm(2) versus left PA 27. 2 ± 12. 3 mm(2); p = 0. 1). Freedom from significant RV dysfunction for S1P survivors at 3, 6, 12, 36, and 48 months was 94.4% ± 3.1%, 88.7% ± 4.4%, 86.7% ± 4.7%, 83.9% ± 5.3%, and 79.7 ± 6.7%, respectively. Norwood RV-PA promotes balanced branch PA growth. The RV-to-PA shunt with proximal valvelike hood modification significantly reduces proximal anastomotic stenosis and need for early shunt revision. Limited early shunt diastolic reversal flow into the RV and subsequent early unloading of RV during BDG might preserve ventricular performance.

Modeling and Analysis of an Energy-Efficient Mobility Management Scheme in IP-Based Wireless Networks

An energy-efficient mobility management scheme in IP-based wireless networks is proposed to reduce the battery power consumption of mobile hosts (MHs). The proposed scheme manages seven MH states, including transmitting, receiving, attention/cell-connected, attention/paging area(PA)-connected, idle, off/attached, and detached states, to efficiently manage battery power, radio resources, and network load. We derive the stationary probabilities and steady state probabilities of the seven MH states for the proposed scheme in IP-based wireless networks in compact form. The effects of various input parameters on MH steady state probabilities and power consumption are investigated in the proposed scheme compared to the conventional scheme. Network costs such as cell updates, PA updates, binding-lifetime-based registrations, and paging messages are analyzed in the proposed and conventional schemes. The optimal values of PA size and registration interval are derived to minimize the network cost of the proposed scheme. The combined network and power costs are investigated for the proposed and conventional schemes. The results provide guidelines to select the proper system parameters in IP-based wireless networks.

Investigation of Microholes Produced by Focused Ion Beam Micromachining

This paper discusses the microfabrication of microholes using focused ion beam and investigation of geometrical integrity of microholes. Different combination of aperture size, probe current, acceleration voltage was applied for micromachining and optimized based on taper angle. Microholes with 3.0 μm of diameter were milled according to the optimized parameter using bitmap mode. The depth range of microholes was 1.0-5.5 μm. The hole’s depth and taper angle were investigated for characterization. Each of the microholes was cross sectioned for investigation. A relationship of taper angle (θ), depth and aspect ratio were plotted. Low aspect ratio (less than 1) would give the lower taper angle and hence better integrity. Acceleration voltage of 25 kV, probe current of 41.5 pA and aperture size of 4 nm produced lower taper angle for different aspect ratio.

Spatial modeling of extraction and enforcement in developing country protected areas

Budget constraints prohibit protected area managers (PAMs) in developing countries from completely deterring extraction and the resulting resource degradation. Because benefits from extraction are a function of distance, PAMs have an opportunity to patrol in a spatial pattern that minimizes degradation for a given budget level. This paper develops a spatial model of a game between a PAM and neighboring villagers to determine the optimal patterns of extraction and enforcement under various constraints. It demonstrates the importance of spatial aspects of PA management, reveals the inefficiency of many PA policies, and supports explicitly spatial management schemes such as extraction zones. The framework underpins a discussion of incomplete enforcement, rural welfare, budgetary tradeoffs between PA size and enforcement costs, and PA shape decisions with human-induced edge effects.