Search Results (215)

This paper presents a 17–38 GHz wideband low-noise amplifier (LNA) designed in a 150-nm GaAs pHEMT process. The proposed amplifier adopts a cascode topology with an interstage inductor between the common-source (CS) and common-gate (CG) stages, and a series inductor at the source node of the CS stage for source degeneration. By incorporating these inductors in the amplification stage, simultaneous noise and input matching is facilitated, while achieving flat gain characteristics over a broad frequency range and ensuring stability. In addition, the amplification stage with inductors achieves input matching using only a shunt component in the DC bias path, without any series matching elements. This approach allows the amplifier to achieve simultaneous noise and input matching (SNIM), ensuring low-noise performance over a wide bandwidth. The simulation results show a flat gain of 20–23 dB and a low noise figure of 1.1–2.1 dB over the 17–38 GHz band. Full article

Many novel microwave devices have been developed based on the left-handed (LH) structure. This paper studies three CMOS standing-wave oscillators (SWOs) using an LH LC network. The first SWO is a class-B VCO, and the second SWO is a class-C SWO. The SWOs are implemented with the TSMC 0.18 μm 1P6M CMOS process technology. The SWOs utilize two units of an LH LC resonator, and the LC resonator is shunted with a pair of cross-coupled transistors to compensate for the loss in the LC resonator. The first and second SWOs utilize two O-shaped inductors to form a unit cell with capacitors. The third SWO utilizes an eight-shaped inductor and an orthogonal transformer to conserve the die area and suppress the magnetic coupling noise. The die area of the third oscillator is 0.986 × 0.756 mm². The SWO can generate differential signals in the frequency range of 8.3 GHz–9.3 GHz (10.83%), and its measured figure of merit (FOM) is −188.6 dBc/Hz at a 1 MHz offset frequency. Full article

In the purpose of enhancing solar cell efficiency and sustainability, zinc selenide (ZnSe) and silicon (Si) play indispensable roles, offering a compelling combination of stability and transparency while also highlighting their abundant availability. This study utilizes the SCAPS_1D tool to explore diverse heterojunction setups, aiming to solve the nuanced correlation between key parameters and photovoltaic performance, therefore contributing significantly to the advancement of sustainable energy solutions. Exploring the performance analysis of heterojunction solar cell configurations employing ZnSe and Si elements, various configurations including SnO₂/ZnSe/p_Si/p⁺_Si, SnO₂/CdS/p_Si/p⁺_Si, TiO₂/ZnSe/p_Si/p⁺_Si, and TiO₂/CdS/p_Si/p⁺_Si are investigated, delving into parameters such as back surface field thickness (BSF), doping concentration, operating temperature, absorber layer properties, electron transport layer properties, interface defects, series and shunt resistance. Among these configurations, the SnO₂/ZnSe/p_Si/p⁺_Si configuration with a doping concentration of 10¹⁹ cm⁻³ and a BSF thickness of 2 μm, illustrates a remarkable conversion efficiency of 22.82%, a short circuit current density (J_sc) of 40.33 mA/cm², an open circuit voltage (V_oc) of 0.73 V, and a fill factor (FF) of 77.05%. Its environmentally friendly attributes position it as a promising contender for advanced photovoltaic applications. This work emphasizes the critical role of parameter optimization in propelling solar cell technologies toward heightened efficiency and sustainability. Full article

This retrospective review examines whether there is a difference in all-cause mortality in patients who required surgical intervention for neovascular glaucoma (NVG, N = 186) versus primary open-angle glaucoma (POAG, N = 190). Cox proportional hazard models compared mortality across three models: unadjusted, age-adjusted (Model 1), and age-, hypertension-, and diabetes-adjusted (Model 2). In all models, NVG patients who required glaucoma surgery had a higher all-cause mortality rate compared to those with POAG who underwent similar procedures: unadjusted (HR 2.22, (1.59, 3.10), p < 0.0001), Model 1 (HR 2.99, 95% CI (2.12, 4.22), p < 0.0001), and Model 2 (HR 1.88, 95% CI (1.27, 2.80), p < 0.0018). In Model 1, those with NVG due to PDR had a higher all-cause mortality rate after glaucoma surgery than those with NVG secondary to CRVO (HR 2.00, 95% CI (1.19, 3.45), p < 0.0095). Patients treated with CPC had higher all-cause mortality rates than those treated with tube shunt in all models: unadjusted (HR 1.82, 95% CI (1.33, 2.47), p < 0.0001), Model 1 (HR 1.91, 95% CI (1.40, 2.61), p < 0.0001), and Model 2 (HR 1.50, 95% CI (1.04, 2.16), p < 0.03). We observed a higher all-cause mortality rate among patients with NVG requiring glaucoma surgery compared to those with POAG requiring similar surgeries, which could suggest that NVG patients requiring glaucoma surgery had more compromised systemic health. Full article

This paper presents a highly linear two-stage InGaP/GaAs power amplifier integrated circuit (PAIC) using a dynamic predistorter for 5G small-cell applications. The proposed predistorter, based on a diode-connected transistor, utilizes a supply voltage to accurately control the linearization characteristics by adjusting its dc current. It is connected in parallel with an inter-stage of the two-stage PAIC through a series configuration of a resistor and an inductor, and features a shunt capacitor at the base of the transistor. These passive components have been optimized to enhance the linearization performance by managing the RF signal’s coupling to the diode. Using these optimized components, the AM−AM and AM−PM nonlinearities arising from the nonlinear resistance and capacitance in the diode can be effectively used to significantly flatten the AM−AM and AM−PM characteristics of the PAIC. The proposed predistorter was applied to the 2.6 GHz two-stage InGaP/GaAs HBT PAIC. The IC was tested using a 5 × 5 mm² module package based on a four-layer laminate. The load network was implemented off-chip on the laminate. By employing a continuous-wave (CW) signal, the AM−AM and AM−PM characteristics at 2.55–2.65 GHz were improved by approximately 0.05 dB and 3°, respectively. When utilizing the new radio (NR) signal, based on OFDM cyclic prefix (CP) with a signal bandwidth of 100 MHz and a peak-to-average power ratio (PAPR) of 9.7 dB, the power-added efficiency (PAE) reached at least 11.8%, and the average output power was no less than 24 dBm, achieving an adjacent channel leakage power ratio (ACLR) of −40.0 dBc. Full article

Background/Objectives: This study aimed to evaluate the results of continuous intracranial pressure (ICP) monitoring in children with macrocephaly or rapidly increasing head circumference (HC) diagnosed as benign external hydrocephalus (BEH). Here, we report the absolute ICP measurements, ICP pulsatility, and slow ICP waves after at least 48 h of continuous monitoring in a cohort of 36 children diagnosed with BEH. Methods: A prospective study of continuous ICP monitoring was performed in 36 consecutive children with macrocephaly (HC above the 97.5th percentile) or rapidly increasing HC (at least crossing two percentile curves), diagnosed with BEH (22 boys and 14 girls with a mean age of 23.6 ± 13.3 months, minimum: 6, maximum 65), using an epidural sensor. For the first four children in the study, hard copies of the ICP values were obtained using an analog recorder. Starting from the fifth patient, the ICP signal was sampled at 200 Hz and stored on a computer using a computer-based data acquisition and analysis system (LabChart v8.1 software). Results: Clinical signs or symptoms were identified in 20 patients (55.6%). Delayed motor or language development was noted in 18 (50%) and 20 (55.6%) patients, respectively. In 13 patients, the enlargement of the subarachnoid spaces was found to be associated with an additional condition. The median of mean ICP values for the entire cohort was 17 mmHg, with a minimum of 6.7 mmHg and a maximum of 29 mmHg. All patients exhibited a percentage of B waves exceeding 20% during the night, with a median value of 47.4% (min: 23.2, max: 75). Three children had nocturnal plateau waves. At night, regular ICP recordings alternated with periods of significant increases in ICP, often exceeding 10 mmHg above baseline values. High-amplitude B waves were noted during these episodes, and the amplitude of the cardiac waveform at the peak of the B waves was consistently greater than 5 mmHg, displaying an abnormal morphology (P2 > P1). A ventriculoperitoneal shunt was implanted in 30 of the 36 patients. Conclusions: Patients with BEH may present significant abnormalities in ICP. Monitoring this variable in certain cases can assist in determining the necessity for surgical treatment. Full article

In this study, a single-pole double-throw (SPDT) switch for Sub-6 GHz application is designed. In particular, a shunt inductor is connected to the antenna port of the switch for ESD (electrostatic discharge) protection in RF (radio frequency) front end module. The shunt inductor not only serves as an ESD protection device, but also serves as a component of a parallel resonance circuit to suppress insertion loss of the switch. In addition, in order to secure the power handling capability, transistors turned off in the transmit (Tx) mode are implemented as quadruple-gate transistors. An SPDT switch is fabricated using GaAs pHEMT provided in the 500 nm GaAs BiFET process to verify the feasibility of the proposed switch structure. The operating frequency is set from 3 GHz to 5 GHz. The insertion loss and isolation measured in the Tx mode are lower than 0.35 dB and higher than 31.6 dB, respectively. The insertion loss and isolation measured in the Rx mode are lower than 0.32 dB and higher than 33.9 dB, respectively. The chip size including test pads is 0.890 × 0.875 mm². Full article

It is well-established that mitochondrial dysfunction plays a critical role in the development of pulmonary hypertension (PH). However, the molecular mechanisms and how the individual electron transport complexes (ETC) may be affected are poorly understood. In this study, we identified decreased ETC Complex I activity and assembly and linked these changes to disrupted mitochondrial bioenergetics in pulmonary arterial endothelial cells (PAECs) isolated from a lamb model of PH with increased pulmonary blood flow (Shunt). These derangements were associated with decreased mitochondrial activity of the protein tyrosine kinase, pp60^Src. Treating Control PAECs with either the Src family kinase inhibitor, PP2, or the siRNA-mediated knockdown of pp60^Src was able to recapitulate the adverse effects on ETC Complex I activity and assembly and mitochondrial bioenergetics. Conversely, restoring pp60^Src activity in lamb PH PAECs re-established ETC Complex I activity, improved ETC Complex I assembly and enhanced mitochondrial bioenergetics. Phosphoprotein enrichment followed by two-dimensional gel electrophoresis and tandem mass spectrometry was used to identify three ETC Complex I subunits (NDUFS1, NDUFAF5, and NDUFV2) as pp60^Src substrates. Finally, we demonstrated that the pY levels of NDUFS1, NDUFAF5, and NDUFV2 are decreased in lamb PH PAECs. Enhancing mitochondrial pp60^Src activity could be a therapeutic strategy to reverse PH-related mitochondrial dysfunction. Full article

Upscaling perovskite solar cells and modules requires precise laser patterning for series interconnection and spatial characterization of cell parameters to understand laser–material interactions and their impact on performance. This study investigates the use of nanosecond (ns) and picosecond (ps) laser pulses at varying fluences for the P3 patterning step of perovskite solar cells. Hyperspectral photoluminescence (PL) imaging was employed to map key parameters such as optical bandgap energy, Urbach energy, and shunt resistance. The mappings were correlated with electrical measurements, revealing that both ns and ps lasers can be utilized for effective series interconnections with minimal performance losses at optimized fluences. Our findings provide a deeper understanding of fluence-dependent effects in P3 patterning. Moreover, the results demonstrate that the process window is robust, allowing for reasonable cell performance even with deviations from optimal parameters. This robustness, coupled with the scalability of the laser patterning process, emphasize its suitability for industrial module production. Full article

Background/Objectives: Studies have indicated that forgoing lung shunt fraction measurement in select patients undergoing Yttrium 90 (Y90) transarterial radioembolization (TARE) may be safe without sacrificing efficacy. This study evaluated the safety and efficacy of a streamlined treatment in patients with small hepatocellular carcinoma (HCC) receiving resin-based TARE. Methods: Patients who received single-session Y90 TARE between September 2023 and May 2024 were retrospectively evaluated. Treatment response was evaluated at the 3-month follow-up using the modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria. Adverse events (AEs) ≥ Grade 3 were recorded post-procedurally at 3 months. The time from the interventional radiology clinic visit to the procedure date was compared to patients receiving the conventional TARE treatment. Results: Ten consecutive patients were treated with 12 treatments. Each treatment targeted an isolated lesion with median size of 2.5 cm (IQR: 2.1, 2.9). Two patients received two treatments (one for treatment of a separate lesion and the other for the initial incomplete targeting of the tumor). The median delivered tumor dose was 377.7 Gy (IQR: 246.5, 570.1). No patients developed ≥ Grade 3 AEs post-TARE. Complete response was achieved in 11/12 patients (92%). The conventional cohort consisted of 60 patients, all OPTN T2 treated with radiation segmentectomy with glass microspheres. Patients undergoing SSMT had a median time from clinic visit to treatment of 26.5 days (IQR: 15.3, 39) vs. 61 days (IQR: 48, 88.8) in the conventional TARE group (p < 0.001). Conclusions: Streamlined single-session resin-based Y90-TARE in patients with OPTN T2 stage HCC is feasible, efficacious, safe, and associated with reduced time to treatment. Full article

(1) Background: Prevalence of patent foramen ovale (PFO) in the general population is estimated at around 24%. We hypothesized that right-to-left shunting (RLS) resulting from PFO might contribute to angina symptoms in patients with coronary artery spasm (CAS), potentially triggered by vasoactive metabolites. Therefore, the aim of this study was to investigate the prevalence of PFO-related RLS in patients with documented CAS. (2) Methods: This single-center prospective cohort study included patients with documented CAS undergoing transthoracic echocardiography (TTE), including a contrast bubble study between 2021 and 2023. The Seattle Angina Questionnaire (SAQ) and Migraine Disability Assessment (MIDAS) were used to survey patients. (3) Results: RLS (PFO group) was observed in 11 of the 48 patients included (23%). In the PFO group, 64% had epicardial spasm and 36% microvascular spasm. Furthermore, RLS was more prevalent in patients with CAS and concomitant migraine (29%). Remarkably, the density plot of the SAQ summary score showed a worse score for patients with RLS (median of 38 [Q1–Q3: 31–49]) than patients without RLS (median of 49 [Q1–Q3: 41–55]) (p = 0.0282). (4) Conclusions: The prevalence of RLS due to PFO in patients with CAS was in line with the PFO prevalence in the general population, and patients with RLS are more symptomatic according to the SAQ summary score. Whether PFO closure could be beneficial to patients with CAS and concomitant migraine requires further investigation. Full article

Background: Atrial septal defect (ASD) is a prevalent congenital heart condition, resulting in left-to-right shunting. Untreated ASDs may be associated with complications, including right-sided heart failure, pulmonary hypertension, and atrial arrhythmias. Percutaneous ASD closure, performed with various occluder devices, has become the preferred approach for symptomatic patients with suitable anatomy, yet data on device-specific efficacy and safety profiles remain limited. Methods: This study was a retrospective, single-center analysis involving patients who underwent percutaneous ASD closure between January 2000 and February 2023. Data on patient characteristics, indications for the procedure, procedural details, and clinical outcomes were extracted from electronic medical records. Endpoints included complications at the puncture site, pericardial effusion, atrial arrhythmias, device-related thrombus formation, and overall survival. Results: A total of 195 patients were included (mean age 53.6 ± 16.2 years; 60.5% female). Three different devices were used: Amplatzer ASD occluder (n = 111), Gore Septal Occluder (n = 67), and Occlutech ASD occluder (n = 17). Initial procedural success rate was 90.8%, with no significant differences observed between devices. Periprocedural complication rates were low and comparable across all devices. New-onset atrial fibrillation within the first month post-implantation occurred in 7.5% of patients with the Gore device, compared to 0.9% with the Amplatzer device (p = 0.03) and 0% with the Occlutech device. No statistically significant differences were observed among the devices regarding thrombus formation, late-onset pericardial effusion, device erosion, or stroke. Conclusions: Percutaneous ASD closure demonstrates high procedural success and low complication rates across different occluder devices, supporting its efficacy and safety as a treatment for adults. Although the Gore device showed a higher incidence of new-onset AF compared to the Amplatzer device, no significant differences were observed regarding thrombus formation, pericardial effusion, device erosion or stroke. Full article

Potential-induced degradation (PID) presents a critical reliability issue for solar photovoltaic (PV) modules, with three primary types identified in the literature, namely, PID_s (shunting type), PID_p (polarization type), and PID_c (corrosion type). Electrochemical/electrical impedance spectroscopy (EIS) is a highly effective but underutilized technique for differentiating between these PID mechanisms. When used alongside conventional I–V measurements (e.g., I_sc, V_oc, and FF), EIS offers direct insights into parameters such as R_s, R_p, and C_p, making it a valuable tool for PID type differentiation. In this study, two four-cell glass–glass modules were investigated using p-base PERC monofacial cells with EVA and POE encapsulants. Results indicate that V_oc and FF remained nearly unchanged under +1000 V stress for both EVA and POE modules, suggesting a minimal impact of PID stress on these parameters. However, I_sc was reduced by approximately 8.5% in the EVA module and 10% in the POE module. For the POE module, surface recombination (PID_p) is likely responsible for the I_sc loss, as R_s, R_p, and C_p showed no significant variation. Conversely, in the EVA module, the combined effects of surface recombination and junction recombination (PID_jr) are the probable cause of the I_sc loss, as evidenced by remarkable changes in R_p and C_p. The observed decrease in R_p for the EVA module is attributed to reduced dynamic diode resistance rather than ohmic shunt resistance. This reduction is linked to recombination currents induced by junction trap centers, formed by the positive voltage PID stress in the encapsulant, which contains trace amounts of oxidizable species such as CH₃COOH and/or H₂O. The objective of this study is to evaluate the impact of PID stress on the electrical characteristics of glass–glass PV modules with different encapsulants, utilizing a combined EIS and I–V approach to distinguish between PID mechanisms. The findings highlight the critical role of the encapsulant type in determining PID susceptibility, with the EVA module exhibiting significant degradation linked to junction recombination losses. These insights underscore the necessity of optimizing encapsulant materials to enhance PV module durability and reliability in real-world applications. Full article

In the contemporary global context, excessive fossil fuel consumption remains a critical issue, particularly within the transportation sector. Electric vehicles offer a promising alternative due to their durability and reduced greenhouse gas emissions. However, their rapid adoption has introduced significant challenges, including increased network power losses, deteriorating voltage profiles, and declining substation power factors. This study proposes an approach that integrates fuzzy objective optimization with African Vulture Optimization (AVO) to determine the optimal sitting and sizing of distributed generations (DG), shunt capacitors (SC), and electric vehicle charging stations (EVCS) within radial distribution systems (RDS). The proposed methodology is evaluated on the standard IEEE-69 bus RDS. A detailed comparative analysis between the proposed simultaneous optimization approach for DGs, SCs, and EVCSs and with the traditional two-staged method is presented. The findings indicate that the proposed strategy not only matches but surpasses the performance of existing strategies for the reduction of power losses and enhancement of bus voltage profiles. Key findings include a significant reduction in active and reactive power line loss, with losses minimized by 85.90% and 82.15%, respectively. In addition, an improvement in the minimum bus voltage to 0.98 p.u. is also achieved. Thereafter, the proposed issue is solved in different loading scenarios to present the effectiveness of the approach under different operating conditions. This research effectively demonstrates the complexities introduced by EVCS integration and addresses the issue with simultaneous optimal sitting and sizing of DGs, SCs, and EVCSs that significantly enhance the sustainability and efficiency of RDS. Full article

Purpose: Porto-systemic shunting (PSS) in patients with Abernethy malformation (AM) or obstruction of the portal vein (OVP) is often associated with normal liver parenchyma and hepatic function. This association provides an interesting natural model for studying the brain functional connectivity changes secondary to PSS but independently from hepatic (dys)function. Because PSS can be eliminated with appropriate interventions, these particular conditions offer a unique physio-pathological model where the same patient can be studied in both “active PSS” and “absent PSS” conditions (pre- and post-cure analyses). Methods: Four children (<18 years) who were evaluated for Abernethy malformation (n = 2) or portal cavernoma (n = 2) and underwent corrective surgery (living-donor liver transplantation for AM, or Meso-Rex bypass for OPV, respectively) were included in the study. Brain magnetic resonance imaging and resting-state functional magnetic resonance imaging (rest-fMRI) were acquired in all patients before and after the corrective surgery. A functional connectome analysis was performed before (“active PSS” condition) and after (“absent PSS”—physiological condition) the cure of PSS. Results: As a result of the cancelation of PSS, rest-fMRI connectomics revealed a statistically significant (p < 0.05 family-wise error) improvement in global brain functional connectivity in both groups following each surgical procedure. Conclusions: In this clinical model of isolated PSS (with absence of hepatic dysfunction), brain functional connectivity was altered even in young patients and in the absence of hyperammonemia; moreover, specific interventions to cancel out PSS consequently significantly improved brain functional connectivity. Full article