Search Results (56)

Air conditioners are a critical adaptation measure against heat- and cold-related risks under climate change. However, their electricity use and refrigerant leakage increase greenhouse gas (GHG) emissions. This study developed a data-driven life-cycle assessment (LCA) framework for residential room air conditioners in Japan by integrating large-scale field operation data with life-cycle climate performance (LCCP) modeling. We aggregated 1 min records for approximately 4100 wall-mounted split units and evaluated the 10-year LCCP across nine climate regions. Using the annual operating hours and electricity consumption, we classified the units into four behavioral quadrants and quantified the life-cycle GHG emissions and parameter sensitivities for each. The results show that the use-phase electricity dominated the total emissions, and that even under the same climate and capacity class, the 10-year per-unit emissions differed by roughly a factor of two between the high- and low-load quadrants. The sensitivity analysis identified the heating hours and the setpoint–indoor temperature difference as the most influential drivers, whereas the grid CO₂ intensity, equipment lifetime, and refrigerant assumptions were of secondary importance. By replacing a single assumed use scenario with empirical profiles and behavior-based clusters, the proposed framework improves the representativeness of the LCA for air conditioners. This enabled the design of cluster-specific mitigation strategies. Full article

Traditional low-cost DC drives, such as Buck converter-fed DC drives, do not take into consideration the power quality requirements regarding the total harmonic distortion (THD) and the input power factor (PF). This paper proposes a high-performance one-quadrant DC drive based on the ultra-sparse matrix rectifier (USMR). The scheme is suitable for single-quadrant applications such as DC pumping systems. The proposed system leverages the advantages of the USMR, such as the accomplishment of the IEEE standards requirements related to harmonic limits and distortions of the AC currents and operation at (or near) unity PF. Two pulse width modulation (PWM) techniques were investigated: the hysteresis current controller with a tolerance band and the triangular carrier-based PWM modulator. The system was studied under different operating conditions. The obtained results demonstrate the high performance of the USMR system with both types of PWM techniques. A comparative study with the one-quadrant Buck converter-based DC drive was conducted. The USMR-based DC drive outperforms the conventional scheme in power quality issues. The quantitative assessment proves the validity and suitability of the USMR for developing high-performance DC drives for single-quadrant applications. Full article

Background: Peritoneal metastasis (PM) from colorectal cancer (CRC) carries a poor prognosis. The Peritoneal Cancer Index (PCI) is among the principal prognostic stratification tools, yet the prognostic value of the anatomical distribution of disease beyond total PCI is underexplored. This pilot study evaluated whether quadrant-specific involvement adds prognostic information in patients undergoing cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC), with a focused analysis of oligometastatic disease (PCI ≤ 6). Methods: A single-institution cohort of 48 CRC-PM patients treated with CRS + HIPEC was analyzed. Primary endpoints were OS, DFS, and PRFS, with a focused evaluation of the oligometastatic subset (PCI ≤ 6). Comparative statistics used Student’s two-sample t test for continuous variables and chi-square or two-sided Fisher’s exact tests for categorical variables. Survival was estimated by Kaplan–Meier with log-rank tests, and prognostic factors were evaluated using Cox regression. Results: Median follow-up was 177 months (IQR 87–224). Outcomes favored PCI ≤ 6: 5-year OS and DFS were 54% and 37.5% versus 6.6% and 0% for PCI > 6, and median OS 64 vs. 29 months (log-rank p = 0.007), median DFS 30 vs. 7 months (p = 0.0002), and median PRFS 26 vs. 8 months (p = 0.0002). In the PCI ≤ 6 subset (n = 27), quadrant 3 (left upper quadrant) was associated with higher recurrence risk and shorter DFS, remaining independently prognostic for DFS (p = 0.005) and PRFS (p = 0.005). For PRFS, quadrants 7 and 8 also showed associations on univariable analysis; Q7 remained independent (p = 0.047), whereas Q8 was borderline (p = 0.077). A histology-related signal at Q8 (p = 0.011) was exploratory due to very small mucinous and signet-ring strata. Sidedness and synchronicity yielded no significant differences in quadrant involvement within PCI ≤ 6. No quadrant effects were observed in PCI > 6. Conclusions: PCI remains the dominant prognostic determinant after CRS + HIPEC, yet in oligometastatic disease, the anatomical distribution adds complementary prognostic information, particularly involvement of Q3 and Q7. These findings are hypothesis-generating and warrant validation in larger, preferably multicenter cohorts with standardized quadrant mapping. If confirmed, quadrant-directed operative planning, including consideration of prophylactic resection in selected high-risk regions, could be prospectively evaluated. Full article

The article addresses the challenges of beam position tracking in Free-Space Optical Communication (FSOC) systems. A review of available photodetector technologies is presented, highlighting their operating principles and applications in optical links. The analysis indicates that most current monitoring devices function with the visible and near- or short-infrared ranges. However, due to the propagation characteristics of radiation in terrestrial environments, the mid-wave infrared (MWIR) region offers particularly promising opportunities. To the end, the work introduces a novel detector module based on an MWIR quadrant detector capable of simultaneously performing two essential tasks: monitoring beam position and receiving transmitted data. Such an integrated approach has the potential to significantly simplify the design of mobile FSOC systems, especially those requiring accurate transceivers’ tracking. The concept was validated through laboratory experiments on an MWIR link model, where both the signal bandwidth and position transfer function of the quadrant detector were examined. Full article

Background: Conservative mastectomy with prepectoral breast reconstruction is becoming increasingly widespread and validated in recent years. Today, while aesthetic advantages and improvement in quality-of-life outcomes are widely acknowledged, oncological safety remains subject of debate. There is limited evidence on residual breast tissue after conservative mastectomy, and it still represents an unknown risk for local recurrence. The recent spread of this surgical technique precludes a standardized surgical approach in case of local recurrence of ipsilateral breast cancer, and the lack of evidence in the literature complicates the decision-making process. The objective of this study is to describe the surgical treatment of local relapses for breast cancer patients following conservative mastectomy and prepectoral implant-based reconstruction. Methods: Between January 2018 and May 2024 at a single institution, 648 consecutive patients underwent conservative mastectomy and prepectoral reconstruction as their primary treatment. We identified 12 patients with T1-2 breast cancer who subsequently had histologically confirmed ipsilateral breast cancer recurrence and a local wide excision or radical mastectomy were performed. Each clinical case was discussed in a multidisciplinary meeting to define the most appropriate surgical treatment. At time of diagnosis of recurrence, patients with lymph node metastasis or systemic involvement were excluded from the study. Results: Among 648 consecutive patients who underwent conservative mastectomy, 12 with histologically confirmed ipsilateral breast cancer recurrence were included. The mean interval to recurrence was 43 months (range 10–76 months) from the primary operation. Recurrence sites were as follows: upper outer quadrant in four patients (33.4%), upper inner quadrant in three (25.0%), lower inner quadrant in two (16.6%), lower outer quadrant in one (8.4%), and central quadrant with nipple involvement in two (16.6%). Of the 12 patients, 9 (75%) underwent wide local excision, including 2 who also received partial capsulectomy, while 3 (25%) required radical mastectomy with implant removal. Adjuvant radiation therapy was administered to 6 patients (50%)—5/6 (83.3%) in the excision group and 1/6 (16.7%) in the mastectomy group. No significant differences were observed in distant disease–free survival or overall survival between the two groups. Conclusions: Currently, surgical treatment of ipsilateral breast tumor recurrence following conservative mastectomy and prepectoral breast reconstruction is not reported in the literature, and this study represents the first instance where wide local excision is described. The management of ipsilateral recurrence should be discussed in multidisciplinary meetings and could be performed safely in selected cases, sparing the prosthesis and avoiding radical mastectomy. Full article

Accurate diagnosis of gastrointestinal (GI) diseases typically requires invasive procedures or imaging studies that pose the risk of various post-procedural complications or involve radiation exposure. Bowel sounds (BSs), though typically described during a GI-focused physical exam, are highly inaccurate and variable, with low clinical value in diagnosis. Interpretation of the acoustic characteristics of BSs, i.e., using a phonoenterogram (PEG), may aid in diagnosing various GI conditions non-invasively. Use of artificial intelligence (AI) and improvements in computational analysis can enhance the use of PEGs in different GI diseases and lead to a non-invasive, cost-effective diagnostic modality that has not been explored before. The purpose of this work was to develop an automated AI model, You Only Listen Once (YOLO), to detect prominent bowel sounds that can enable real-time analysis for future GI disease detection and diagnosis. A total of 110 2-minute PEGs sampled at 44.1 kHz were recorded using the Eko DUO^® stethoscope from eight healthy volunteers at two locations, namely, left upper quadrant (LUQ) and right lower quadrant (RLQ) after IRB approval. The datasets were annotated by trained physicians, categorizing BSs as prominent or obscure using version 1.7 of Label Studio Software^®. Each BS recording was split up into 375 ms segments with 200 ms overlap for real-time BS detection. Each segment was binned based on whether it contained a prominent BS, resulting in a dataset of 36,149 non-prominent segments and 6435 prominent segments. Our dataset was divided into training, validation, and test sets (60/20/20% split). A 1D-CNN augmented transformer was trained to classify these segments via the input of Mel-frequency cepstral coefficients. The developed AI model achieved area under the receiver operating curve (ROC) of 0.92, accuracy of 86.6%, precision of 86.85%, and recall of 86.08%. This shows that the 1D-CNN augmented transformer with Mel-frequency cepstral coefficients achieved creditable performance metrics, signifying the YOLO model’s capability to classify prominent bowel sounds that can be further analyzed for various GI diseases. This proof-of-concept study in healthy volunteers demonstrates that automated BS detection can pave the way for developing more intuitive and efficient AI-PEG devices that can be trained and utilized to diagnose various GI conditions. To ensure the robustness and generalizability of these findings, further investigations encompassing a broader cohort, inclusive of both healthy and disease states are needed. Full article

Grid capacity constraints present a prominent challenge in the construction of ultra-fast charging (UFC) stations. Active load management (ALM) and battery energy storage systems (BESSs) are currently two primary countermeasures to address this issue. ALM allows UFC stations to install larger-capacity transformers by utilizing valley capacity margins to meet the peak charging demand during grid valley periods, while BESSs rely more on energy storage batteries to solve the gap between the transformer capacity and charging demand This paper proposes a four-quadrant classification method and defines four types of schemes for UFC stations to address grid capacity constraints: (1) ALM with a minimal BESS (ALM-Smin), (2) ALM with a maximal BESS (ALM-Smax), (3) passive load management (PLM) with a minimal BESS (PLM-Smin), and (4) PLM with a maximal BESS (PLM-Smax). A generalized comparison framework is established as follows: First, daily charging load profiles are simulated based on preset vehicle demand and predefined charger specifications. Next, transformer capacity, BESS capacity, and daily operational profiles are calculated for each scheme. Finally, a comprehensive economic evaluation is performed using the levelized cost of electricity (LCOE) and internal rate of return (IRR). A case study of a typical public UFC station in Tianjin, China, validates the effectiveness of the proposed schemes and comparison framework. A sensitivity analysis explored how grid interconnection costs and BESS costs influence decision boundaries between schemes. The study concludes by highlighting its contributions, limitations, and future research directions. Full article

Introduction: The maximum residual tumour size after surgery is the most important prognostic factor related to survival in advanced ovarian cancer. This parameter can be subjectively determined by the surgeon at the end of the operation and by a radiologist with a postoperative CT scan. CT scans after optimal cytoreduction can reveal residual/progressive disease in a significant percentage of patients, ranging from 21% to 49%. The aim of this study was to validate the PCI scale for the systematic reading of postoperative CT scans in patients with advanced ovarian cancer and to establish it as a new prognostic marker. Material and Methods: Patients with advanced ovarian cancer (FIGO II-IV), diagnosed between 2007 and 2019 in Hospital La Fe Valencia, in whom cytoreductive surgery was performed (achieving R0 or R1), and in whom a postoperative CT scan was performed between the third and eighth week post-surgery and prior to the start of chemotherapy, were included. Two different radiologists who specialised in gynaecological malignancy performed a blind analysis of the CT scans. They then read the images using the Peritoneal Carcinomatosis Index (PCI) scale, which divides the abdominopelvic cavity into 12 quadrants. Using the Qualitative Assessment (QA) scale, they established the presence or lack of tumour disease in each of these regions, with QA 1–2 being definitely/probably normal, QA 3 indeterminate and QA 4–5 probably/definitely metastatic. Results: This study included a cohort of 117 patients. The radiological study found measurable tumour disease in up to 49% of patients after optimal primary cytoreduction (R0 or R1). There was “substantial agreement” between the results of the two radiologists according to the Kappa analysis (0.624). Both radiologists’ (A and B) findings were related to a significant reduction in both disease-free survival (DFS) and overall survival (OS) in patients with residual disease in the CT scan (QA 4–5) versus those without macroscopic disease (QA 1–3) (p < 0.05). Conclusions: The finding of radiological tumour disease on a standardised and systematised postsurgical CT scan prior to the initiation of adjuvant chemotherapy is associated with the prognosis of patients with advanced ovarian cancer. Full article

This study introduces two bivariate extensions of the recently proposed weighted discretized Fréchet–Weibull distribution, termed as bivariate weighted discretized Fréchet–Weibull (BWDFW) distributions. These models are specifically designed for analyzing two-dimensional discrete datasets and are developed using two distinct structural approaches: the minimum operator (BWDFW-I) and the maximum operator (BWDFW-II). A rigorous mathematical formulation is presented, encompassing the joint cumulative distribution function, joint probability mass function, and joint (reversed) hazard rate function. The dependence structure of the models is investigated, demonstrating their capability to capture positive quadrant dependence. Additionally, key statistical measures, including covariance, Pearson’s correlation coefficient, Spearman’s rho, and Kendall’s tau, are derived using the joint probability-generating function. For robust statistical inferences, the parameters of the proposed models are estimated via the maximum likelihood estimation method, with extensive simulation studies conducted to assess the efficiency and accuracy of the estimators. The practical applicability of the BWDFW distributions is demonstrated through their implementation in two real-world datasets: one from the aviation sector and the other from the security and safety domain. Comparative analyses against four existing discrete bivariate Weibull extensions reveal the superior performance of the BWDFW models, with BWDFW-I (minimum operator based) exhibiting greater flexibility and predictive accuracy than BWDFW-II (maximum operator based). These findings underscore the potential of the BWDFW models as effective tools for modeling and analyzing bivariate discrete data in diverse applied contexts. Full article

Objective: Nephroureterectomy (NU) is a challenging multi-quadrant surgical procedure that involves intra–infra- and retroperitoneal dissection. The introduction of the da Vinci Xi platform has further improved the minimally invasive approach. With the Xi robotic system, single docking for multi-quadrant dissection is now feasible and increasingly popular. Herein, we redefined the surgical technique by optimizing minimal port usage, maximizing template visualization, and utilizing the Xi platform’s retargeting system, based on our experience with 15 patients. Methods: This single-center cohort study was based on the experience of a single surgeon with 15 patients who underwent robotic radical nephroureterectomy (RRNU) between 2019 and 2024, performed via the one docking, three-port technique. Patient data were retrospectively collected and analyzed from the medical records. Results: The cohort’s median age was 79 years, with male predominance of 80%. The median operative time was 133 min, with 60% of procedures completed within 150 min; longer times (>150 min) were due to additional intraoperative non-robotic procedures. Median blood loss was 100 mL, with two patients requiring intraoperative blood transfusion. Lymph node dissection (LND) in six patients did not significantly affect the overall operative time. The intraoperative and major postoperative complication rates (Clavien-Dindo grade > III) were 13.3%. Conclusions: The use of three robotic ports combined with the Xi platform’s camera-hop feature is a safe and effective technique for multi-quadrant, minimally invasive procedures, particularly in RRNU. This approach facilitates procedural goals and reduces overall operative time. Full article

In the context of high-quality urban renewal, we recognize that heritage renewal must align with sustainable conservation. As an important part of cultural heritage, we find that the conservation value of industrial heritage is often undermined in the pre-decision-making and mid-development phases of adaptive reuse, resulting in an imbalance between sustainable conservation and renewal. The study aims to develop a comprehensive, concise, and objective post-development assessment system for the adaptive reuse of industrial heritage. We establish an assessment system based on the “conservation sustainability” and “added value sustainability” of industrial heritage and create a two-dimensional “conservation–reuse” assessment model. Using the geographic information system (GIS), we build a database of Beijing industrial heritage and assess 19 reused samples with the four-quadrant model. The results show that “added value sustainability” fluctuates between 53.3% and 86.7%, while “conservation sustainability” reaches a low of only 50%, with more than half of the heritage having a conservation degree below the average. This highlights the need for stronger conservation efforts. The findings and methodology of this study provide a database and guidelines for decision-makers to adjust reuse models in a timely manner, ensuring sustainable conservation. Compared to previous assessment models, this model is easier to operate and allows decision-makers to control the dynamic balance of “conservation–reuse” in sustainable renewal. Full article

Silicon carbide (SiC) metal oxide semiconductor field-effect transistors (MOSFETs) are a future trend in traction inverters in electric vehicles (EVs), and their thermal safety is crucial. Temperature-sensitive electrical parameters’ (TSEPs) indirect detection normally requires additional circuits, which can interfere with the system and increase costs, thereby limiting applications. Therefore, there is still a lack of cost-effective and sensorless thermal monitoring techniques. This paper proposes a high-efficiency datasheet-driven method for sensorless estimation utilizing the third-quadrant characteristics of MOSFETs. Without changing the existing hardware, the closure degree of MOS channels is controlled through a dual-gate bias (DGB) strategy to achieve reverse conduction in different patterns with body diodes. This method introduces a MOSFET operating current that TSEPs are equally sensitive to into the two-argument function, improving the complexity and accuracy. A two-stage current pulse is used to decouple the motor effect in various conduction modes, and the TSEP-combined temperature function is built dynamically by substituting the currents. Then, the junction temperature is estimated by the measured bus voltage and current. Its effectiveness was verified through spice model simulation and a test bench with a three-phase inverter. The average relative estimation error of the proposed method is below $7.2\%$ in centigrade. Full article

Background: Diagnoses for right lower quadrant pain in women must include both gynecologic and non-gynecologic causes. In this differential, ovarian torsion and appendicitis are both serious etiologies that can require swift surgical intervention. Ovarian torsion is the least common of the two, accounting for 2.7% of emergency surgery cases according to a 10-year review, while the lifetime risk of appendectomy for females is 23.1%. As many as 2–3% of patients undergoing surgery for acute appendicitis are instead found to have ovarian torsion. However, there are currently only rare case reports of these two conditions co-presenting in the same patient simultaneously, with little discussion on how to be better prepared before entering the operating room. Objective: The purpose of this study is to describe this rare co-presentation to better inform providers of this potential complication and to improve future patient care outcomes. Method: A case report of a patient seen at Tripler Army Medical Center, Honolulu, Hawaii, was assessed. Conclusions: This case shows the rare possibility of dual acute etiologies of abdominal pain warranting urgent surgical management. This case also highlights the need for a multidisciplinary approach in the pre-procedural evaluation of possible competing etiologies of acute abdominal pain that warrant surgical management. Additionally, this case brings up interesting ethical questions regarding informed consent, autonomy, and the obligation of intraoperatively consulted surgeons to provide definitive and indicated surgical care in the absence of prior discussion of possible pathology. Full article

In this study, an urban airspace assessment mechanism is proposed and validated using the actual urban building data, offering a systematic approach to airspace selection for unmanned aerial vehicle (UAV) operations. Two metrics are involved to assess the urban airspace accurately, which are the airspace availability and risk to ground population. The former is measured by analyzing the connectivity of the urban airspace which particularly emphasizes the impact of urban features like buildings and obstacles. The latter is quantized by using a previously proposed risk estimation model, with which an urban risk map can be generated. Quadrant analysis and Pareto ranking are then employed to evaluate the available airspace for UAVs. Quadrant analysis maps the urban airspace availability and risk to ground population onto a two-dimensional space. Additionally, Pareto ranking determines a set of Pareto-optimal solutions wherein no objective can be improved without compromising at least one other objective. The topology of urban airspace could be constructed by using the top 50% of grids ranked by Pareto ranking based on the actual building data. A case study is conducted in a densely populated urban area in Changqing District, Jinan, Shandong Province, China. The connectivity of the airspace topology is verified by employing the A-star algorithm to generate a feasible path for UAVs. Full article

Purpose: It is difficult for small- and medium-sized enterprises to modify themselves to achieve digital transformation; a digital empowerment platform can help small- and medium-sized enterprises (SMEs) to digitalize. Therefore, it is of great significance to identify the key factors of the development of logarithmic words. Design: This study first uses the ISM method to establish a network of influencing factors, identifies key factors from the perspectives of network structure and enterprise competitive advantage, and finally conducts a comprehensive analysis using a six-quadrant matrix. Findings: Capital, talent, and data collection and analysis technology are key factors driving the development of digital empowerment platforms. Standards, accurate and continuous industry information, and efficient and sustained co-operation with empowered industry enterprises and research institutions are key factors in establishing a sustained competitive advantage. This study proposes two development paths for enterprises and two policy recommendations. Originality: (1) The history of digital empowerment platform enterprises is relatively short, and there are relatively few studies on the influencing factors of its development. (2) By employing mathematical network analysis and competitive advantage analysis methods and comprehensively analyzing key factors, this study innovates the multi-factor evaluation method. Full article