Fractional Ratio Research Articles

Pathophysiological role of right ventricular function and interventricular functional mismatch in the development of pulmonary edema in acute heart failure

BackgroundParameters of cardiac function related to the development of pulmonary edema (PE) in acute heart failure (AHF), including right ventricular (RV) function and a mismatch of interventricular function, are not fully elucidated. The aim of this study was to verify the hypothesis that a relatively preserved RV function compared with left ventricular function may be associated with the development of PE by using two-dimensional speckle tracking echocardiography (2DSTE). MethodsHospitalized patients with AHF at 11 institutions were enrolled. PE was defined as lung congestion on chest X-ray with hypoxemia. Patients with systolic blood pressure ≥140 mmHg on admission were defined to have hypertensive AHF. Echocardiographic analyses, including 2DSTE, were performed prior to discharge. The index of mismatch between RV and left ventricular systolic function was assessed by interventricular longitudinal strain difference (IVLSD) which was defined as RV free wall longitudinal strain and left ventricular global longitudinal strain. ResultsOf 610 patients with AHF, 422 (69.2%) had PE. In patients with PE, IVLSD (p = 0.007) and RV fractional area change ratio (p<0.001) was significantly higher than those in patients without PE. In patients with non-hypertensive AHF, RV fractional area change ratio, age, ischemic etiology, and serum brain natriuretic peptide (BNP) levels were independent predictors of PE. In patients with hypertensive AHF, IVLSD, age, and serum BNP levels were independent predictors of PE. ConclusionsPreserved RV function might be one of the underlying mechanisms of the development of PE in AHF. Furthermore, interventricular functional mismatch might be related to the development of PE in hypertensive AHF.

Quantitative Automated Segmentation of Lipiodol Deposits on Cone-Beam CT Imaging Acquired during Transarterial Chemoembolization for Liver Tumors: A Deep Learning Approach

PurposeTo show that a deep learning (DL)–based, automated model for Lipiodol (Guerbet Pharmaceuticals, Paris, France) segmentation on cone-beam computed tomography (CT) after conventional transarterial chemoembolization performs closer to the “ground truth segmentation” than a conventional thresholding-based model. Materials and MethodsThis post hoc analysis included 36 patients with a diagnosis of hepatocellular carcinoma or other solid liver tumors who underwent conventional transarterial chemoembolization with an intraprocedural cone-beam CT. Semiautomatic segmentation of Lipiodol was obtained. Subsequently, a convolutional U-net model was used to output a binary mask that predicted Lipiodol deposition. A threshold value of signal intensity on cone-beam CT was used to obtain a Lipiodol mask for comparison. The dice similarity coefficient (DSC), mean squared error (MSE), center of mass (CM), and fractional volume ratios for both masks were obtained by comparing them to the ground truth (radiologist-segmented Lipiodol deposits) to obtain accuracy metrics for the 2 masks. These results were used to compare the model versus the threshold technique. ResultsFor all metrics, the U-net outperformed the threshold technique: DSC (0.65 ± 0.17 vs 0.45 ± 0.22, P < .001) and MSE (125.53 ± 107.36 vs 185.98 ± 93.82, P = .005). The difference between the CM predicted and the actual CM was 15.31 mm ± 14.63 versus 31.34 mm ± 30.24 (P < .001), with lesser distance indicating higher accuracy. The fraction of volume present ([predicted Lipiodol volume]/[ground truth Lipiodol volume]) was 1.22 ± 0.84 versus 2.58 ± 3.52 (P = .048) for the current model’s prediction and threshold technique, respectively. ConclusionsThis study showed that a DL framework could detect Lipiodol in cone-beam CT imaging and was capable of outperforming the conventionally used thresholding technique over several metrics. Further optimization will allow for more accurate, quantitative predictions of Lipiodol depositions intraprocedurally.

The value of quantitative diffusion tensor imaging indices of spinal cord disorders

BackgroundDifferent lesions affecting the spinal cord can lead to myelopathy. Diffusion tensor imaging (DTI) is widely used to predict the degree of spinal cord microstructure affection and to assess axonal integrity and diffusion directionality. We hypothesized that not all DTI parameters have the same affection with different spinal cord pathologies. The purpose of this study is to assess the value of the quantitative diffusion tensor imaging indices in different spinal cord lesions.ResultsThere is highly statistically significant difference of the fractional anisotropy (FA), relative anisotropy (RA), volume ratio (VR) and secondary eigenvector values (E2 and E3) between various studied cord lesions and control levels. There is no statistically significant difference of the apparent diffusion coefficient (ADC) and the primary eigenvector value (E1) (ANOVA test). The ROC curve analysis showed the higher sensitivity and accuracy were ‘88% and 62.5%, respectively,’ with FA cutoff value about 0.380.ConclusionThe resulted quantitative DTI indices ‘fractional anisotropy, relative anisotropy, volume ratio and secondary eigenvalues’ work as a numerical in vivo marker of overall tissue injury in different pathologies affecting the spinal cord.

A family of nonparametric unit root tests for processes driven by infinite variance innovations

Abstract This paper presents extensions to the family of nonparametric fractional variance ratio (FVR) unit root tests of Nielsen (2009. “A Powerful Test of the Autoregressive Unit Root Hypothesis Based on a Tuning Parameter Free Statistic.” Econometric Theory 25: 1515–44) under heavy tailed (infinite variance) innovations. In this regard, we first develop the asymptotic theory for these FVR tests under this setup. We show that the limiting distributions of the tests are free of serial correlation nuisance parameters, but depend on the tail index of the infinite variance process. Then, we compare the finite sample size and power performance of our FVR unit root tests with the well-known parametric ADF test under the impact of the heavy tailed shocks. Simulations demonstrate that under heavy tailed innovations, the nonparametric FVR tests have desirable size and power properties.

Abnormal fractional flow reserve and non-hyperaemic pressure ratios in patients with severe aortic stenosis and non-obstructive coronary artery disease

Abstract Background Fractional flow reserve (FFR) and non-hyperaemic pressure ratios (NHPRs) are well-validated tools that assess the physiological significance of coronary artery disease (CAD). Low coronary lumen to myocardial mass (V/M) ratio on CT is associated with lower FFR/NHPRs and predisposes towards ischaemia in CAD. Whilst CAD and aortic stenosis (AS) frequently co-exist, patients report angina despite obstructive disease. Purpose We therefore sought to study the interrelationship between V/M and invasive pressure indices in patients with severe AS. Methods 35 patients with severe AS were prospectively recruited as part of CAST-FFR study. Patients underwent CT coronary angiography and invasive pressure-wire assessment. All pressure-indices were assessed in the left anterior descending artery (LAD). Data was extracted to calculate FFR, iFR, diastolic pressure ratios (DPR and dPR) and Diastolic Hyperaemia-free Ratio (DFR). Patient-specific V/M were extracted off-site by independent core lab. Results Mean age was 75±7.5 years, median V/M ratio was 20.7 and mean aortic gradient and DI were 44.3±11.6mmHg and 0.23±0.4 respectively. 79% of patients had CADRADs score of &amp;lt;2. There were moderate positive correlations between FFR/NHPRs and V/M, including FFR (r=0.60), PdPa (r=0.48), iFR (r=0.59), DPR (r=0.59), dPR (r=0.63), DFR (r=0.67), (all p&amp;lt;0.005). In patients with positive pressure assessments, 69% (FFR), 71% (iFR), 70% (DPR) and 65% (DFR) had CADRADs score &amp;lt;2. In severe AS, lower V/M was associated with lower pressure-indices (FFR 0.75 vs 0.86, iFR 0.79 vs 0.92, DFR 0.80 vs 0.91, all p&amp;lt;0.005), leading to high rates of positive physiologic assessment (FFR 88%, PdPa 72%, iFR 67%, DPR 78%, DFR 74%). Conclusion Patients with severe AS exhibit high rates of abnormal FFR and NHPR values, despite having no obstructive CAD. Their propensity for having abnormal physiological results is, in part, influenced by coronary volume to mass ratio. These results are important for clinicians considering using invasive physiological tools to guide revascularisation decisions in patients with severe AS. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Monash University, Cardiac Society of Australia and New Zealand Correlation between NHPR/FFR and VMInvasive pressure indices and VM

Instantaneous wave-free ratio for the assessment of nonculprit lesions in patients with acute coronary syndrome

Abstract Background A physiological assessment with the fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR) is strongly recommended by the European Guidelines of Revascularization to guide percutaneous coronary intervention (PCI) decision making in intermediate coronary stenosis. However, data supporting its use in the pro-inflammatory setting of ACS is weak. Purpose To analyze the usefulness of a physiological coronary evaluation with iFR of nonculprit lesions in patients with ACS. Methods Retrospective multicenter study including patients with ACS and underwent successful revascularization of the culprit vessel and had other nonculpritlesions physiologically evaluated with the iFR between January 2017 and December 2019. The primary endpoint was a composite of cardiac death, nonfatal myocardial infarction, stent thrombosis and new revascularization (MACEs). Results A total of 356 patients with 472 nonculprit lesions were included. The mean age was 66±11 years. The clinical presentation was non-ST-segment elevation myocardial infarction (NSTEMI) in 235 patients and ST-segment elevation myocardial infarction (STEMI) in 121 patients. After a mean follow-up period of 22±10 months, the primary endpoint occurred in 32 patients (9%). There were no differences in outcomes regarding iFR induced treatment strategy (patients with all lesions revascularized vs. patients with at least one lesion deferred for revascularization, 10.5 vs 8.4%, p=0.476). Conclusion The use of the iFR to guide percutaneous coronary intervention decision making in nonculprit lesions seems to be safe, with an acceptable percentage of MACEs at the mid-term follow-up. Funding Acknowledgement Type of funding sources: None. FlowchartSurvival curves by iFR and ACS group

Replica symmetry breaking in coherent and incoherent random lasing modes.

We investigate intensity fluctuations of a weakly scattering optofluidic random laser having coherent and incoherent emission fractions. The coherent part comprises random spikes, whereas the incoherent part forms a broad pedestal in the emission spectra. Evaluating the fractional ratio of the coherent and incoherent parts of the emission, a replica symmetry breaking phase transition is observed independently in both coherent and incoherent parts of the intensity. Also, the incoherent component has higher non-zero correlation values compared to those of the coherent part, implying a larger contribution to mode coupling. Moreover, survival function analysis reveals a significant contribution of the incoherent part on determining the decay profile of lasing intensity.

ПІДБІР КІЛЬКОСТІ ЗУБЦІВ ПЛАНЕТАРНИХ МЕХАНІЗМІВ СХЕМ AA, II, AI, IA, І ЗА ДОПОМОГОЮ ПРОГРАМНОГО ЗАБЕЗПЕЧЕННЯ

Most of the methods for selecting the numbers of teeth of planetary mechanisms are based on general equations that take into account three main conditions for their existence: 1) ensuring a given gear ratio, 2) the condition of alignment, 3) the condition of assembly. The rest of the conditions are not included in the system of equations to be solved and are checked additionally. However, this approach has a number of disadvantages associated with the discreteness of the general equations depending on several parameters. Therefore, a method is proposed for selecting the number of teeth using equations obtained only when taking into account two mandatory conditions for the existence of planetary mechanisms: 1) ensuring a given gear ratio, 2) the condition of alignment. Equations for fitting by this method are presented. The remaining conditions for the existence of planetary gears are checked separately and as a result, unsuitable solutions are excluded. This approach ensures the selection of all existing solutions in a given range of teeth numbers with a relatively small number of iterations, but it is rational only when used on a computer. In this regard, the corresponding software has been written - the Planmex.exe program. A description of this program is given, which allows you to select the number of teeth of the wheels of the proposed schemes of planetary gears with a whole and fractional gear ratio, different modules of wheels on a double satellite, a different number of satellites in a given range of numbers of teeth, depending on the selected driving link. Three variants of optimization of the obtained results of selection of the number of teeth are proposed: 1) minimum mass, 2) maximum speed, 3) maximum efficiency. Coefficients are introduced to compare the results within each optimization option and equations are proposed to determine them. An example of the selection of the number of teeth for different modules of gears on a double satellite of the planetary mechanism of the AI scheme by the proposed method using the Planmex.exe program is given. The optimization of the obtained results is made according to three criteria, taking into account the region of existence of the given scheme.

Direct Comb Vernier Spectroscopy for Fractional Isotopic Ratio Determinations.

Accurate isotopic composition analysis of the greenhouse-gasses emitted in the atmosphere is an important step to mitigate global climate warnings. Optical frequency comb–based spectroscopic techniques have shown ideal performance to accomplish the simultaneous monitoring of the different isotope substituted species of such gases. The capabilities of one such technique, namely, direct comb Vernier spectroscopy, to determine the fractional isotopic ratio composition are discussed. This technique combines interferometric filtering of the comb source in a Fabry–Perot that contains the sample gas, with a high resolution dispersion spectrometer to resolve the spectral content of each interacting frequency inside of the Fabry–Perot. Following this methodology, simultaneous spectra of ro-vibrational transitions of CO and CO molecules are recorded and analyzed with an accurate fitting procedure. Fractional isotopic ratio C/C at 3% of precision is measured for a sample of CO gas, showing the potentialities of the technique for all isotopic-related applications of this important pollutant.

Mobility of Nucleostemin in Live Cells Is Specifically Related to Transcription Inhibition by Actinomycin D and GTP-Binding Motif.

In vertebrates, nucleostemin (NS) is an important marker of proliferation in several types of stem and cancer cells, and it can also interact with the tumor-suppressing transcription factor p53. In the present study, the intra-nuclear diffusional dynamics of native NS tagged with GFP and two GFP-tagged NS mutants with deleted guanosine triphosphate (GTP)-binding domains were analyzed by fluorescence correlation spectroscopy. Free and slow binding diffusion coefficients were evaluated, either under normal culture conditions or under treatment with specific cellular proliferation inhibitors actinomycin D (ActD), 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB), or trichostatin A (TSA). When treated with ActD, the fractional ratio of the slow diffusion was significantly decreased in the nucleoplasm. The decrease was proportional to ActD treatment duration. In contrast, DRB or TSA treatment did not affect NS diffusion. Interestingly, it was also found that the rate of diffusion of two NS mutants increased significantly even under normal conditions. These results suggest that the mobility of NS in the nucleoplasm is related to the initiation of DNA or RNA replication, and that the GTP-binding motif is also related to the large change of mobility.

Magnetic resonance imaging texture analysis for the evaluation of viable ovarian tissue in patients with ovarian endometriosis: a retrospective case-control study.

BackgroundTexture analysis has been used as a method for quantifying image properties based on textural features. The aim of the present study was to evaluate the usefulness of magnetic resonance imaging (MRI) texture analysis for the evaluation of viable ovarian tissue on the perfusion map of ovarian endometriosis.MethodsTo generate a normalized perfusion map, subtracted T1-weighted imaging (T1WI), T1WI and contrast-enhanced T1W1 with sequences were performed using the same parameters in 25 patients with surgically confirmed ovarian endometriosis. Integrated density is defined as the sum of the values of the pixels in the image or selection. We investigated the parameters for texture analysis in ovarian endometriosis, including angular second moment (ASM), contrast, correlation, inverse difference moment (IDM), and entropy, which is equivalent to the product of area and mean gray value.ResultsThe perfusion ratio and integrated density of normal ovary were 0.52±0.05 and 238.72±136.21, respectively. Compared with the normal ovary, the affected ovary showed significant differences in total size (p<0.001), fractional area ratio (p<0.001), and perfusion ratio (p=0.010) but no significant differences in perfused tissue area (p=0.158) and integrated density (p=0.112). In comparison of parameters for texture analysis between the ovary with endometriosis and the contralateral normal ovary, ASM (p=0.004), contrast (p=0.002), IDM (p<0.001), and entropy (p=0.028) showed significant differences. A linear regression analysis revealed that fractional area had significant correlations with ASM (r2=0.211), IDM (r2=0.332), and entropy (r2=0.289).ConclusionMRI texture analysis could be useful for the evaluation of viable ovarian tissues in patients with ovarian endometriosis.

Projected lifetime cancer risk from cone-beam computed tomography for orthodontic treatment.

ObjectiveTo estimate the projected cancer risk attributable to diagnostic cone-beam computed tomography (CBCT) performed under different exposure settings for orthodontic purposes in children and adults.MethodsWe collected a list of CBCT machines and their specifications from 38 orthodontists. Organ doses were estimated using median and maximum exposure settings of 105 kVp/156.8 mAs and 130 kVp/200 mAs, respectively. The projected cancer risk attributable to CBCT procedures performed 1–3 times within 2 years was calculated for children (aged 5 and 10 years) and adult (aged 20, 30, and 40 years) male and female patients.ResultsFor maximum exposure settings, the mean lifetime fractional ratio (LFR) was 14.28% for children and 0.91% for adults; this indicated that the risk to children was 16 times the risk to adults. For median exposure settings, the mean LFR was 5.25% and 0.58% for children and adults, respectively. The risk of cancer decreased with increasing age. For both median and maximum exposure settings, females showed a higher risk of cancer than did males in all age groups. Cancer risk increased with an increase in the frequency of CBCT procedures within a given period.ConclusionsThe projected dental CBCT-associated cancer risk spans over a wide range depending on the machine parameters and image acquisition settings. Children and female patients are at a higher risk of developing cancer associated with diagnostic CBCT. Therefore, the use of diagnostic CBCT should be justified, and protective measures should be taken to minimize the harmful biological effects of radiation.

Elezanumab, a human anti-RGMa monoclonal antibody, promotes neuroprotection, neuroplasticity, and neurorecovery following a thoracic hemicompression spinal cord injury in non-human primates

Spinal cord injury (SCI) is a devastating condition characterized by loss of function, secondary to damaged spinal neurons, disrupted axonal connections, and myelin loss. Spontaneous recovery is limited, and there are no approved pharmaceutical treatments to reduce ongoing damage or promote repair. Repulsive guidance molecule A (RGMa) is upregulated following injury to the central nervous system (CNS), where it is believed to induce neuronal apoptosis and inhibit axonal growth and remyelination. We evaluated elezanumab, a human anti-RGMa monoclonal antibody, in a novel, newly characterized non-human primate (NHP) hemicompression model of thoracic SCI. Systemic intravenous (IV) administration of elezanumab over 6 months was well tolerated and associated with significant improvements in locomotor function. Treatment of animals for 16 weeks with a continuous intrathecal infusion of elezanumab below the lesion was not efficacious. IV elezanumab improved microstructural integrity of extralesional tissue as reflected by higher fractional anisotropy and magnetization transfer ratios in treated vs. untreated animals. IV elezanumab also reduced SCI-induced increases in soluble RGMa in cerebrospinal fluid, and membrane bound RGMa rostral and caudal to the lesion. Anterograde tracing of the corticospinal tract (CST) from the contralesional motor cortex following 20 weeks of IV elezanumab revealed a significant increase in the density of CST fibers emerging from the ipsilesional CST into the medial/ventral gray matter. There was a significant sprouting of serotonergic (5-HT) fibers rostral to the injury and in the ventral horn of lower thoracic regions. These data demonstrate that 6 months of intermittent IV administration of elezanumab, beginning within 24 h after a thoracic SCI, promotes neuroprotection and neuroplasticity of key descending pathways involved in locomotion. These findings emphasize the mechanisms leading to improved recovery of neuromotor functions with elezanumab in acute SCI in NHPs.

Utility of multiparametric pre-operative magnetic resonance imaging in differentiation of chordoid meningioma from the other histopathological subtypes of meningioma-a retrospective study.

To determine the magnetic resonance imaging (MRI) features which could pre-operatively differentiate chordoid meningioma (CM) from other histopathological subtypes of meningioma. Retrospective analysis of pre-operative MRI of cases with histopathologically confirmed diagnosis of meningioma during the last 5 years at our institute was done. T1W, T2W, FLAIR sequences, and post-contrast enhancement were evaluated on a qualitative scale. Normalized ADC ratios (nADCR) and normalized fractional anisotropy ratios (nFAR) were derived. The intratumoral susceptibility score (ITSS), presence of sunburst pattern of vasculature, bone changes, tumour-parenchyma interface, and oedema-to-tumour ratio were also determined. A total of 81 lesions were analyzed out of which 15 were CM. CM showed a higher relative contrast enhancement as compared to all other subtypes except for angiomatous and microcystic meningioma. Relative signal intensity on FLAIR could differentiate CM from transitional meningioma. nFAR was found to be significantly higher in fibroblastic meningioma and significantly lower in microcystic meningiomas as compared to CM. Anaplastic meningiomas were remarkable for bone changes and an ill-defined tumour-brain interface in significantly higher proportion of cases as compared to CM. nADCR > 1.5 was found to be an independent predictor of CM with a sensitivity of 84.6%, specificity of 89.8%, positive predictive value of 64.7%, and negative predictive value of 96.4%. Routine pre-operative MRI may be able to differentiate CM from other meningioma subtypes and a cut-off value of greater than 1.5 for nADCR could be predictive of > 50% chordoid histology of meningioma with a high sensitivity, specificity, and negative predictive value.

A brief note on economic recessions, banking reform and the future of capitalism

In my book «Money, Bank Credit, and Economic Cycles» (1st Spanish Edition 1992, 2nd English Edition 2009) I present a detailed analysis of the Austrian Business Cycle Theory. Now I will concentrate on the financial crisis and the current worldwide economic recession as one of the most challenging problems we must now cope with and the way in which the Austrian Business Cycle Theory can help us to understand its causes and the best approach to economic recovery.&#x0D; Having witnessed the intellectual and practical defeat of socialism specially during the last decades of the twentieth century, in my opinion one of the main challenges that still remains for the future of Capitalism is the urgent need to privatize money by dismantling the organ of central monetary planning: the Central Bank. In other words, real Socialism, represented by state money, Central banks and financial administrative regulations, is still in force in the monetary and credit sectors of the so called free market economies.&#x0D; As a result of this fact we experience regularly in the area of money and credit all the negative consequences established by the Theorem of the Impossibility of Socialism discovered by those distinguished members of the Austrian School of Economics Ludwig von Mises and Friedrich Hayek.&#x0D; Specifically, the central planners of state money are unable to know, to follow and to control the changes in both the demand and supply of money. Furthermore, the whole financial system is based on the legal privilege given by the state to private bankers to act with a fractional reserve ratio in relation with the demand deposits they receive from their clients. As a result of this privilege, private bankers are not true financial intermediaries, but are mainly creators of deposits materializing in credit expansions. These credit expansions are artificial and do not correspond to any previous increases in the voluntary savings of the citizens. In this way the current fractional reserve banking system, tends to worsen and amplify the systemic intertemporal distortions and investment misallocations that the macroeconomic planners working for central banks induce in the production structure of the whole real economy. These distortions manifest themselves in the stages of financial bubbles, economic boom, overall malinvestment and afterwards in the stages of financial crisis, deep economic recession and unemployment.

Fractional Curve in Adult Spinal Deformity: Is it a Driver of or a Compensation for Coronal Malalignment?

This was a retrospective review of the multicenter adult spine deformity database. The objective of this study was to investigate the role of the fractional curve (FC) on global coronal malalignment. Despite being very common, the role of the coronal FC as either a driver or compensation for global coronal malalignment is not well documented. Patients with the following characteristics were extracted from a prospective multicenter database: lumbar/thoracolumbar (TL) major coronal curve >15 degrees, apex at T11-L3, lower end vertebra at L3 or L4, above 45 years old, and FC >5 degrees. In addition to the classic radiographic parameters, baseline analysis included Cobb angle, pelvic obliquity (PO), fractional ratio (fractional Cobb/main Cobb), the sum of PO and FC, as well as the coronal Qiu classification. Curves distribution (TL vs. FC) were compared across the 3 Qui types, and the role of the FC was investigated. A total of 404 patients (63 y old, 83.3% female) were included: 43 patients were classified as type B, 120 as type C, and 241 were coronally balanced (type A). Compared with the balanced patients, type C patients had similar major TL Cobb angles but significantly larger fractional Cobb angles (17.5 vs. 22.3 degrees, P<0.001). By opposition, type B patients had significantly larger major TL Cobb angles (49 vs. 41 degrees, P=0.001) but smaller fractional Cobb angles (P<0.001). PO>5 degrees in the same direction as FC was more common in type B patients (20%) than in type C patients (7.5%), which suggests the preferential role of pelvic compensation. Our findings challenge the idea that FC is only a compensatory curve below a main lumbar or TL curve. In type B patients, FC acts as a compensation mechanism but fails to maintain coronal alignment despite the presence of PO. In type C patients, however, the lumbosacral FC acts as a primary driver of coronal malalignment. Level III.

Millimeter-Wave Dual-Band Bandpass Filter With Large Bandwidth Ratio Using GaAs-Based Integrated Passive Device Technology

In this letter, a millimeter-wave (mm-wave) dual-band bandpass filter is proposed with large bandwidth ratio by using gallium arsenide (GaAs)-based integrated passive device (IPD) technology. To realize small chip size, one dual-mode on-chip resonator is designed by using quasi-lumped capacitors and microstrip lines. In addition, multiple transmission zeroes are generated by further introducing both the electric and magnetic couplings between adjacent resonators. To realize large bandwidth ratio of two passbands, the external quality factors are investigated at both passband, and can be independently controlled. For demonstration, a 28-/50-GHz dual-band bandpass filter is designed, fabricated, and measured. The fractional bandwidth ratio is 7.8, which is much larger than the reported on-chip filters. Meanwhile, very low insertion loss of 0.58-dB is realized for the lower passband at 28 GHz, indicating the proposed dual-band bandpass filter a promising application in mm-wave wireless systems.

Forces in Axial Flux Magnetic Gears with Integer and Fractional Gear Ratios

This paper presents a comparison of two variants of an axial flux magnetic gear (AFMG), namely, with integer and fractional gear ratios. Based on calculations derived with the use of three-dimensional numerical models, the torque characteristics of the analyzed AFMGs are computed and verified on a physical model. The greatest emphasis is put on the detailed decomposition and analysis of local forces in modulator pole pieces (also used in the structural analysis) within the no-load and maximal load conditions. The authors also describe the unbalanced magnetic forces (UMF) in the axial and radial directions resulting from the construction of the considered AFMGs variants, and their possible effects in the context of the use of additive manufacturing (AM) in prototypes. The paper also proposes an effective method for limiting the axial strain by using the asymmetry of the air gaps, which slightly reduces the torque transmitted by AFMGs. Finally, a static strength analysis was presented that allows us to assess the effects of local forces in the form of modulator disc deformation for selected cases of air gap asymmetry.

Influence of lesion and disease subsets on the diagnostic performance of the quantitative flow ratio in real-world patients

The quantitative flow ratio (QFR) is a novel angiography-based computational method assessing functional ischemia caused by coronary stenosis. This study aimed to evaluate the diagnostic performance of quantitative flow ratio (QFR) in patients with angina and acute myocardial infarction (AMI) and to identify the conditions with low diagnostic performance. We assessed the QFR for 1077 vessels under fractional flow ratio (FFR) evaluation in 915 patients with angina and AMI. The diagnostic accuracies of the QFR for identifying an FFR ≤ 0.8 were 95.98% (95% confidence interval [CI] 94.52 to 97.14%) for the angina group and 92.42% (95% CI 86.51 to 96.31%) for the AMI group. The diagnostic accuracy of the QFR in the borderline FFR zones (> 0.75, ≤ 0.85) (91.23% [95% CI 88.25 to 93.66%]) was significantly lower than that in others (difference: 4.32; p = 0.001). The condition accompanying both AMI and the borderline FFR zone showed the lowest QFR diagnostic accuracy in our data (83.93% [95% CI 71.67 to 92.38]). The diagnostic accuracy was reduced for tandem lesions (p = 0.04, not correcting for multiple testing). Our study found that the QFR method yielded a high overall diagnostic performance in real-world patients. However, low diagnostic accuracy has been observed in borderline FFR zones with AMI, and the hybrid FFR approach needs to be considered.

The reasons why fractional flow reserve and instantaneous wave-free ratio are similar using wave separation analysis

Background and objectivesFractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are the two most commonly used coronary indices of physiological stenosis severity based on pressure. To minimize the effect of wedge pressure (Pwedge), FFR is measured during hyperemia conditions, and iFR is calculated as the ratio of distal and aortic pressures (Pd/Pa) in the wave-free period. The goal of this study was to predict Pwedge using the backward wave (Pback) through wave separation analysis (WSA) and to reflect the effect of Pwedge on FFR and iFR to identify the relationship between the two indices.MethodsAn in vitro circulation system was constructed to calculate Pwedge. The measurements were performed in cases with stenosis percentages of 48, 71, and 88% and with hydrostatic pressures of 10 and 30 mmHg. Then, the correlation between Pback by WSA and Pwedge was calculated. In vivo coronary flow and pressure were simultaneously measured for 11 vessels in all patients. The FFR and iFR values were reconstructed as the ratios of forward wave at distal and proximal sites during hyperemia and at rest, respectively.ResultsBased on the in vitro results, the correlation between Pback and Pwedge was high (r = 0.990, p < 0.0001). In vivo results showed high correlations between FFR and reconstructed FFR (r = 0.992, p < 0.001) and between iFR and reconstructed iFR (r = 0.930, p < 0.001).ConclusionsReconstructed FFR and iFR were in good agreement with conventional FFR and iFR. FFR and iFR can be expressed as the variation of trans-stenotic forward pressure, indicating that the two values are inferred from the same formula under different conditions.