Drainage Length Research Articles

Improved lateral figure-of-merit of heteroepitaxial α-Ga2O3 power MOSFET using ferroelectric AlScN gate stack

In this Letter, we demonstrate heteroepitaxial α-Ga2O3 MOSFETs using an aluminum scandium nitride (AlScN) ferroelectric gate stack. Owing to ferroelectric effects, α-Ga2O3 MOSFETs with the AlScN/HfO2 gate stack (FGFET) exhibited enhanced electrical performance compared with a HfO2 gate dielectric (IGFET) for variable gate–drain lengths (10, 15, 20 μm). A remnant polarization value of the AlScN deposited on a HfO2 layer was measured to be about 30 μC/cm2. The subthreshold swing (SS) and field-effect mobility (μFE) of IGFET was extracted at 1814 mV/dec and 13.9 cm2/V s, respectively. However, the FGFET exhibits a reduced SS of 552 mV/dec with enhanced μFE of 42.7 cm2/V s owing to the negative capacitance of the ferroelectric AlScN. Furthermore, a lateral figure-of-merit of 17.8 MW/cm2 was achieved for the FGFET, far surpassing the 8.3 MW/cm2 of the IGFET. The proposed ferroelectric AlScN/HfO2 stack can be a promising gate structure for improving both transfer and breakdown characteristics in heteroepitaxial α-Ga2O3 power devices.

The Effects of Systemic Tranexamic Acid Administration on Drainage Volume, Duration of Drain Placement, and Length of Hospital Stay in Skin- and Nipple-Sparing Mastectomies with Immediate Expander-Based Breast Reconstruction

Background: Skin- (SSM) and nipple-sparing (NSM) mastectomies are frequently performed surgeries with a considerable risk for post-operative hematoma or seroma. Tranexamic acid (TXA) is a potent antifibrinolytic drug commonly used in many surgical fields but rather novel in plastic and, specifically, breast surgery. This study investigates the influence of TXA in patients undergoing SSM or NSM with expander-based reconstruction (EbR) on post-operative outcomes. Methodology: A retrospective study was conducted on 132 patients undergoing uni- or bilateral SSM or NSM with EbR between May 2015 and March 2022. Patients receiving systemic TXA treatment for 48 h following a standardized protocol were compared to those who received no treatment. Multivariable linear regression was performed to identify influencing factors and quantify their effect on drainage volume, duration of drain placement, length of hospital stay, post-operative bleeding, and seroma formation. Results: The 132 patients underwent a total of 155 mastectomies (72 in the TXA group, 83 in the control group). TXA significantly reduced drainage volume (−22.3 mL, p = 0.011). Duration of drain placement and length of hospital stay were significantly shorter in the TXA group (p < 0.001 and p = 0.001). No significant side effects were reported. Conclusion: TXA is a safe drug if administered respecting the well-defined contraindications. Systemic TXA administration significantly reduces drainage volume in patients undergoing SSM or NSM and should encourage surgeons to reconsider using drains in post-operative protocols. Duration of drain placement and length of hospital stay were significantly reduced in the TXA group but other factors like resection weight might have a more substantial impact.

Therapeutic effects of single-port thoracoscopic anatomical segmentectomy on early-stage non-small-cell lung cancer.

We aimed to assess the therapeutic effects of single-port thoracoscopic anatomical segmentectomy on early-stage non-small-cell lung cancer (NSCLC). Sixty patients with early-stage NSCLC admitted from December 2022 to July 2023 were selected and divided into a lobectomy group (n = 30) and a segmentectomy group (n = 30) according to the different procedures. Their perioperative indicators, pre-operative and post-operative pulmonary function indicators, pain degree 24 h, 48 h, 72 h and 7 day after operation, the incidence of post-operative complications and recurrence, survival and mortality rates 1 year after operation were compared. The segmentectomy group had significantly smaller intraoperative blood loss, shorter length of drainage and length of hospital stay and longer operation time than those of the lobectomy group (P < 0.05). The pulmonary function decreased significantly in both groups 1 week, 1 month and 3 months after operation. Compared with the lobectomy group, the forced expiratory volume in 1 s per cent, forced-vital capacity per cent and maximal voluntary ventilation of the segmentectomy group significantly increased at each time point after operation (P < 0.05). The Visual Analogue Scale scores 24 h, 48 h, 72 h and 7 days after operation were significantly lower in the segmentectomy group than those in the lobectomy group (P < 0.05). There were no significant differences in the incidence of post-operative complications and recurrence, survival and mortality rates 1 year after operation between the two groups (P > 0.05). Single-port thoracoscopic anatomical segmentectomy has obvious therapeutic effects on early-stage NSCLC, characterised by smaller surgical trauma, milder post-operative pain and less impact on pulmonary function.

Discontinuation of Cerebro-Spinal Fluid (CSF) Drainage in Acute Hydrocephalus: A Prospective Cohort Study and Exploratory Data Analysis.

The optimal management of CSF drainage in acute hydrocephalus, in particular when to initiate drain weaning, remains uncertain. This study aimed to evaluate the impact of timing and method of drain weaning on patient outcomes. This prospective observational study in a large-volume tertiary neuroscience centre included all adult patients who required temporary CSF drainage for acute hydrocephalus of any cause between January 2020 and March 2021. Contemporaneous data collection was conducted, including patient demographics, time to clamp, weaning methods, and clinical outcomes of hospital length of stay (LOS), rate of shunt insertion, drain-related infections, and mechanical complications. Univariate and multivariate statistical analyses were performed to identify the independent associations of timing-related factors. A total of 69 patients were included (mean age = 59.4 years). A total of 59% had CSF diversion for aneurysmal subarachnoid haemorrhage, and 88% had EVD drainage. The length of drainage prior to the first clamp was significantly associated with the overall length of drainage (p < 0.0001), LOS (p = 0.004), and time to shunt (p = 0.02) following multivariate adjustment. For each day delayed in initiating the drain challenge, the overall LOS increased by an additional 1.25 days. There was no association between the weaning method and LOS, the rate of shunting, or CNS infection; however, those in the gradually weaned group had more mechanical complications, such as drain blockage or CSF leakage, than those rapidly weaned (p = 0.03) after adjustment. This study recommends challenging the drain early via a rapid wean to reduce LOS, mechanical complications, and possibly infections. The consequences of temporary CSF diversion have significant implications at financial and patient levels, but the quality of evidence regarding weaning remains poor. Further randomised multicentre studies and national databases of practice are required to allow definitive conclusions to be drawn.

Relationships Between Radiomorphometric Parameters of the Maxillary Sinus and Development of Sinusitis: A Cone Beam Computed Tomography Study.

The presence of maxillary sinusitis can complicate dental procedures. This study aimed to explore the relationship between maxillary sinus radiomorphometric factors, observed in cone-beam computed tomography (CBCT) images, and inflammatory sinus diseases. In this cross-sectional study, CBCT images from patients referred to a private radiology center between January 2018-January 2020 were analyzed. Sinuses were categorized as healthy or pathologic. Sinus pathologies were further classified into subgroups; mucosal thickening, retention cyst, partial opacification, complete opacification and air-fluid level. Radiomorphometric parameters, including ostium height, drainage length, ostium opening size, and drainage angle, were measured in the coronal plane. A p value less than 0.05 was considered statistically significant. A total of 433 maxillary sinuses from 258 patients were examined. Height of the ostium and drainage path length in the groups with various sinus pathologies was significantly higher than in healthy sinuses (p < 0.05 for each subgroup) except for air-fluid level (p = 0.334 and p = 0.520, respectively). Drainage path length was significantly longer in all patient groups. Maxillary ostium openings were significantly smaller in retention cyst and partial opacification subgroups, compared to healthy patients (p = 0.000 and p = 0.006, respectively) except for mucosal thickening or air-fluid levels conditions (p = 0.094 and p = 0.62). Drainage angle did not significantly differ. This study reveals that longer drainage length is associated with a higher risk of inflammatory sinus diseases, with increased severity. Smaller ostium openings are linked to retention cysts and partial opacification, while higher ostium locations increase the likelihood of sinus inflammation and disease severity.

Short-Term Bed Rest is not a Risk Factor for Venous Thromboembolism After Endoscopic Skull Base Surgery

IntroductionDeep venous thromboembolisms (DVT) increase morbidity in postoperative patients, and no current guidelines identify which patients undergoing endoscopic endonasal approach (EEA) to the skull base may be at increased risk. Postoperative care for these patients often includes a period of inactivity to prevent transient ICP shifts which may impact skull base reconstruction. We seek to characterize if postoperative bedrest puts EEA patients at increased risk of developing thromboembolic complications. MethodsRetrospective chart review of patients undergoing intradural surgery with primary skull base reconstruction for intraoperative CSF leak via EEA for any skull base pathology between July 2018 and May 2024 was performed yielding 221 patients who met inclusion criteria. Univariate and multivariable regression were performed with patient demographics, extent of approach, intraoperative leak flow rate, bedrest duration, presence and length of postoperative lumbar drainage (LD), and use of postoperative mechanical VT prophylaxis. ResultsThe mean age of included patients was 52.6 ± 16.8 years, 48% were male, and 3.6% of patients had DVTs. Age (OR 1.01, 95% CI 0.96-1.06, p=0.83), sex (OR 0.40, 95% CI 0.05-2.19, p=0.31), BMI (OR 0.98, 95% CI 0.87-1.07, p=0.74), extended approach (OR 0.80, 95% CI 0.13-4.36, p=0.80), CSF leak flow rate (OR 5.71, 95% CI 0.77-118.90, p=0.14), bedrest duration (OR 1.06, 95% CI 0.77-1.27, p=0.60), and presence of LD (OR 1.10, 95% CI 0.55-2.02, p=0.76) were not significant predictors of postoperative VTE incidence on multivariable analysis. ConclusionShort-term bedrest after EEA is not a risk factor for development of VTE in the immediate postoperative period.

Ambipolar current suppression in drain elevated TFET using a novel extended drain structure with a moderate doping profile

In this paper, a simple and compact silicon-based Elevated and Extended Drain with Hetero-Dielectric Gate Oxide TFET (EED HDGO TFET) is proposed to suppress the ambipolar current in Elevated Drain TFET (ED TFET). The proposed device structure uses a moderately doped drain with a doping concentration of ∼1018 cm−3 and a high drain length of ∼50–100 nm. The combination of the moderate drain doping profile and the extended drain length reduced the impact of the electrostatic potential from the positive voltage of the drain electrode on the channel–drain junction. This structural technique widens the tunneling width at the channel–drain region causing the tunneling current to decrease significantly. The tunneling width is further increased by structurally isolating the channel–drain junction region from the gate electrode. Thus, distancing the channel–drain junction from both the gate electric field and the static drain potential of the drain electrode causes full suppression of the ambipolar (Iamb) current. The proposed structure yields Iamb and Ioff as low as ∼10−18 A/μm and ∼10−17 A/μm respectively, while maintaining the Ion as ∼0.3 mA. The device is optimized for low power and high-speed digital circuits through intensive parametric analysis on gate–drain Cgd and the gate–source Cgs capacitances for various device parameters.

Flood risk assessment in Kogi State Nigeria through the integration of hazard and vulnerability factors

Annually, Kogi State in Nigeria experiences significant flooding events, leading to serious fatalities, the destruction of livelihoods, and damage to vital infrastructure. This study presents a multi-faceted approach and methodology to generate a state-wide flood risk map by analyzing both flood vulnerability and flood hazard factors. Seven flood hazard factors (drainage length, distance to river, elevation, slope, rainfall, distance from confluence/dam area, and geomorphology) and vulnerability factors (population density, female population, land cover, road length, distance from hospitals, literacy rate, and employment rate) were ranked and weighted based on their contributions to flooding within the state using the Fuzzy Analytical Hierarchy Process (FAHP). From these, the Flood Hazard Index (FHI), Flood Vulnerability Index (FVI), and Flood Risk Index (FRI) were derived. Results showed that Kabba, Idah, Olamabor, Kotonkar, and the southern part of Ajaokuta LGAs exhibit high flood vulnerability due to dense populations, remoteness from roads and critical infrastructure, and considerable distances from healthcare facilities. Likewise, LGAs exhibiting a very high FHI occur along the geographic zones bounded by the confluence of the Niger and Benue rivers, specifically along the Lokoja area, and the Kotonkar, Kogi, Bassa, and Ibaji LGAs. Five flood risk classes—very low, low, moderate, high, and very high FRI classes—occupy 26.82, 31.12, 22.07, 15.26, and 4.71% of the area, respectively. Out of 295 villages, 65 villages are spread across the high flood risk zone. The safest LGAs include Ankpa, Omala, Dekina, Ijumu, Kabba, and Mopa-Muro LGAs.

Lessons from short chest drain management for primary spontaneous pneumothorax.

Video-assisted thoracic surgery (VATS) bullectomy is the mainstay treatment for primary spontaneous pneumothorax (PSP) but we encounter patients with pain due to chest tube. This study investigated the postoperative outcomes of shortened silicone drain as a chest tube after VATS bullectomy to reduce pain. The current study included patients aged < 30years who underwent VATS bullectomy for PSP. Patients with normal intrathoracic lengths of the silicone drain placed in a loop at the apex toward the diaphragm were categorized as Group L, whereas those with the silicone drain shortened to approximately 10cm and placed toward the apex were classified as Group S. Postoperative pain evaluated using a numerical rating scale (NRS) and other perioperative outcomes were compared between the groups. Altogether, 43 patients were included, with 22 in Group L and 21 in Group S, respectively. The NRS before chest tube removal was significantly lower in Group S (mean, 2.1) than in Group L (4.4; p = 0.001). In Group L, 4 patients (p = 0.017) required early chest tube removal than expected due to severe pain whereas none in Group S required this intervention; additionally, more patients needed additional analgesics than in Group S (p = 0.003). In VATS bullectomy for PSP, the pain intensity could be reduced by shortening the intrathoracic length of the silicone drain, compared to a longer intrathoracic length of the silicon drain. Our findings contribute to the establishment of optimal postoperative management of general thoracic surgery.

Unit cell consolidation of a PVD incorporated soft soil: Comparative of 2D axisymmetric and plane strain analysis considering ideal and actual drain

The paper presents two-dimensional (2D) finite element-based study of a surcharge-induced consolidating unit cell model comprising fully saturated soft soil. Radial drainage in the unit cell is ensured through a single prefabricated vertical drain (PVD) along with vertical drainage through the top surface. Finite element based 2D axisymmetric and plane strain modelling has been conducted by considering the smearing of cohesive medium. The PVD is represented by both 1D drain element (ideal drain) and through geometric modelling considering well resistance. The parameters for the ‘Soft Soil’ model for the cohesive medium are adopted from the subsurface data at Krishnapatnam Ultra Mega Power Project (KUMPP), India. Comparative assessment of unit-cell consolidation is carried out between the 2D axisymmetric and equivalent plane strain condition based on Hird’s permeability compatibility approach. The two approaches yielded noticeable disparity in the time rates of consolidation for time factor ≤ 0.4, beyond which the disparity decreases, and the two methods lead to identical results beyond time factor = 4. Further, the influence of permeability of a geometrically modelled PVD and the height of unit cell on the time-rate of consolidation is elucidated, thereby manifesting the importance of well resistance and drainage length in such analyses.

Analysis of P-N Junction Length of Drain and Source in MOSFET Transistor Through TCAD Simulation

This paper delves into the convergence of mathematical and computer science principles within the realm of electronics engineering, particularly focusing on device-level transistor restructuring. A pressing challenge confronting the semiconductor sector is the persistent escalation of leakage current alongside technological advancements. At the heart of any chip or semiconductor device lies the transistor, serving as its fundamental building block. Among the various forms of leakage current, subthreshold leakage stands out as a dominant component in transistors. Within this study, a systematic exploration of the numerical association governing the physical configuration of MOSFET and leakage amount specifically the subthreshold one is undertaken. One innovative algorithm is crafted to facilitate the automated tracking of transistor structures, laying the groundwork for subsequent analyses. The simulation framework is meticulously constructed by leveraging mathematical formulations derived from the algorithmic outputs. Remarkably, the results obtained from the simulation conducted through TCAD software exhibit a remarkable proximity to established mathematical models. Given the ubiquity of Complementary Metal Oxide Semiconductor (CMOS) technology in contemporary semiconductor fabrication, it serves as the cornerstone for the simulation endeavours herein.

Analysis Of P-N Junction Length of Drain and Source in MOSFET Transistor Through TCAD Simulation

This paper delves into the convergence of mathematical and computer science principles within the realm of electronics engineering, particularly focusing on device-level transistor restructuring. A pressing challenge confronting the semiconductor sector is the persistent escalation of leakage current alongside technological advancements. At the heart of any chip or semiconductor device lies the transistor, serving as its fundamental building block. Among the various forms of leakage current, subthreshold leakage stands out as a dominant component in transistors. Within this study, a systematic exploration of the numerical association governing the physical configuration of MOSFET and leakage amount specifically the subthreshold one is undertaken. One innovative algorithm is crafted to facilitate the automated tracking of transistor structures, laying the groundwork for subsequent analyses. The simulation framework is meticulously constructed by leveraging mathematical formulations derived from the algorithmic outputs. Remarkably, the results obtained from the simulation conducted through TCAD software exhibit a remarkable proximity to established mathematical models. Given the ubiquity of Complementary Metal Oxide Semiconductor (CMOS) technology in contemporary semiconductor fabrication, it serves as the cornerstone for the simulation endeavours herein.

Large‐strain consolidation of vacuum preloading combined with partially penetrating prefabricated vertical drains

AbstractA system of vacuum preloading combined with partially penetrating prefabricated vertical drains (PP‐PVDs) is an effective solution for promoting the consolidation of the dredged marine clay. However, a significant and traditionally challenging‐to‐predict amount of deformation or settlement occurs. Therefore, it is necessary to introduce a three‐dimensional large‐strain consolidation model to consider the length of the vertical drain to determine the consolidation time and degree of consolidation (DoC), and associated settlement. The predictions using the proposed analytical model provide fair agreements with the field data and those in the literature. Parametric studies reveal that to achieve a 90% DoC within 100 days in soft soil, the optimal penetration depth for PP‐PVDs would be 0.7 times the depth of the soil layer. With the increase of DoC, the ratio of excess pore water pressure to applied vacuum pressure (u/P) in the whole soil layer moves toward 1.0. With the increase of PVD penetration ratio (H1/H), more DoC is required to dissipate the excess pore water pressure in the top improved soil layer.

The Use of Next Generation Sequencing to Detect Early Implant Infections: The Future of Microbiology and Targeted Antibiotic Treatment

Abstract Goals/Purpose The presence of fluid around foreign bodies, particularly breast implants, is a well-established phenomenon; However scant data exists regarding the composition of this fluid. The difficulty in studying this fluid arises from the lack of safe access to aspirate fluid post-breast augmentation, and by the loss of sterility once fluid exits the body via a drain bulb as traditionally placed during breast reconstruction. Our innovative breast reconstruction approach utilizes a drainless technique with a dual chamber tissue expander (TE) in the pre-pectoral plane, offering a unique avenue to sterilely aspirate peri-implant fluid through a percutaneous drainage port. In this study, we employ Next Generation Sequencing (NGS), utilizing polymerase chain reaction technology, to discern the composition of microbial DNA within peri-prosthetic breast implant fluid. NGS, known for its precision and cost-effectiveness, circumvents the biases inherent in traditional culture methods. By integrating this cutting-edge technology with our breast reconstruction methodology, we sought to study peri-prosthetic breast implant fluid to better understand when implant infections arise and if peri-prosthetic fluid could detect infections before clinical symptoms arise. Methods/Technique This is a single surgeon, prospective study of patients undergoing mastectomy, followed by pre-pectoral, drainless, TE reconstruction. Peri-prosthetic fluid was collected through the TE drainage port in the OR immediately after closure, at 1 week post op, and 3 weeks post op. This fluid was sent for traditional culture and NGS. Patients were observed for signs of infection, antibiotics, return to OR, or implant loss. Results/Complications 33 breasts from 20 patients were included. Patients had a mean age of 50 years. The average length of drainage was 21 days post-operative, with a mean of 131 cc of fluid drained per breast per week. Eight breasts had concern for skin necrosis. In 25 breasts (76%), complete sterility was achieved at the end of the case with no NGS detection of microorganisms in the initial peri-implant fluid sample. However, NGS detected microorganisms in the initial sample in 8 breasts (24%). In 5 of these 8 breasts, microorganisms were cleared by the 1-week sample and another 2 cleared by 3 weeks. The remaining 1 breast continued to have positive NGS and developed clinical signs of infections by week 2, which were not picked up by traditional culture until week 3. One breast with skin necrosis developed a positive NGS at week 3 and clinical signs of infection at week 4. No other clinical infections were seen throughout the study. Conclusion We are one of the first groups to demonstrate the ability to achieve peri-implant sterility at the time of implant insertion in the operating room. This could have significant implications for understanding the necessity of peri-operative antibiotics following breast implant placement. Our investigation into the microbial composition of ostensibly "sterile" peri-prosthetic breast implant fluid provides insight into when microorganisms arise and when they become clinical infections. These promising preliminary results suggests that peri-prosthetic fluid monitoring through Next-Generation Sequencing (NGS) holds significant potential in preemptively detecting implant infections before the onset of clinical symptoms, thereby reducing infection rates. Furthermore, our findings open avenues for targeted antibiotic therapy, contributing to the imperative goal of antibiotic stewardship. Ongoing work is beginning to explore the impact of microorganisms within the fluid on breast capsule formation, as we strive to enhance our understanding of breast implants and infections.

Comparison of ICG-Guided Near-Infrared Fluorescence Imaging and Modified Inflation-Deflation Method in Identifying the Intersegmental Plane During Lung Segmentectomy of Infants

BackgroundThe identification of the intersegmental plane (ISP) is a crucial step in segmentectomy for children with congenital pulmonary airway malformation (CPAM) due to complex anatomical variations. However, there is very limited literature available on this aspect specifically for infant. In this study, we compared the intravenous indocyanine green (ICG)-guided near-infrared fluorescence (NIRF) imaging method with the modified inflation-deflation method in terms of their perioperative characteristics and summarized our experience. MethodsFrom June 2021 to November 2022, the data of 83 patients with CPAM who underwent segmentectomy by video-assisted thoracoscopic surgery were retrospectively reviewed. Twenty-eight patients underwent ICG-guided NIRF method, and 56 patients underwent the modified inflation-deflation method, characteristics and clinical outcomes were compared. ResultsThe median age of the patients was 4.99 months (4.99 ± 1.51) with a mean body weight of 7.54 kg (7.54 ± 1.99). Both methods could accurately identify the ISP. The time taken to clearly display the ISP was shorter in ICG group than in the modified inflation-deflation group (0.18 ± 0.08 vs. 6.49 ± 1.67 min; P < 0.001), and the surgical duration (61.32 ± 14.28 vs. 88.18 ± 8.03 min; P < 0.001) were significantly shorter in the ICG group too. The two groups exhibited differences in the length of chest tube drainage (1.75 ± 1.24 vs. 2.36 ± 1.54 days; P = 0.072) and the length of hospital stay (4.61 ± 1.75 vs. 5.20 ± 3.07 days; P = 0.078), however, the differences were not statistically significant. There were no significant differences between the two groups in the blood lost and postoperative complications. At a follow-up of more than 1 year after operation, all patients had recovered well without recurrence. ConclusionsAccording to our experience, the ICG-guided NIRF method was safe and feasible for infants during thoracoscopic segmentectomy, it can quickly display the ISP and shorten the surgical duration compared with the modified inflation-deflation method.

Are precautions actually a risk factor in the development of bronchopleural fistula after pneumonectomy? A retrospective analysis of 299 cases.

Bronchopleural fistula most commonly occurs after pneumonectomies, with high morbidity and mortality. A preventive approach is essential. Risk factors can be classified depending on the patient, anatomy, surgical technique, and other causes. Patients (n = 370) who underwent pneumonectomy between 2010 and 2020 were evaluated. The digital media and archive files of the patients (n = 299) were reviewed retrospectively. While 271 patients (90.6%) were male, 28 (9.4%) were female. The mean age was 56.63years. The bronchopleural fistula rate was 14.7% (44/299). Serum protein deficiency, right pneumonectomy, completion pneumonectomy, bronchial manual suturing, advanced stage, prolongation of time after neoadjuvant therapy, length of drain and hospital stay, tissue support for the stump, and short bronchial stump were significant for bronchopleural fistula. Smoking in patients operated on for malignancy and low serum albumin value in benign and chronic infectious diseases were significant in terms of fistula. In patients who developed bronchopleural fistula, the 5-year survival rate was 18.4%. The most important risk factors in bronchopleural fistula depend on the surgical technique and so are completely preventable. Contrary to the literature, short stump and tissue support to the stump were found to be risk factors for fistula. In addition, the effect of the time between neoadjuvant therapy and operation should be examined in further studies.

Investigation of different buffer layer impact on AlN/GaN/AlGaN HEMT using silicon carbide substrate for high-speed RF applications

The AlN/GaN heterostructure on the AlGaN back barrier with different buffer layer structures using a silicon carbide (SiC) substrate was investigated in this work. This study mainly focused on selecting a cost-effective buffer layer with a thickness of more than 1 μm and fewer defects for improving DC/RF performance. The extra epitaxial growth process steps can be avoided by choosing an appropriate, high-quality buffer material called β-Ga2O3 (β-gallium oxide). It has a good lattice match with AlGaN alloys and SiC. It leads to fabricating cost-effective, reliable HEMTs. The GaN buffer has a poor lattice match with SiC; the nucleation layer must be used between GaN and SiC for lattice match to avoid stress defects and dislocations, which helps to reduce buffer traps. The growth of thick GaN crystals leads to high costs and more defects. Creating a solid conduction band barrier with the help of a back-barrier (AlGaN) leads to a boost in the confinement of electrons in both devices. Still, the traps and defects in the GaN buffer do not effectively halt the leakage current compared to the β-Ga2O3 buffer. The T-shaped gate with the impact of LGD (gate to drain length) and LGS (gate to source length) scaling in lateral dimensions was also studied and the device performance was reported. The HEMT with β-Ga2O3 buffer delivers significant results in drain current (2.3 A/mm), transconductance (603 S/mm), and cut-off frequency (486 GHz) for the scaled lateral lengths LG (Gate Length) of 60 nm,LGD of 0.9 μm, and LGS of 0.4 μm. This excellent performance helps to use this HEMT device in cost-effective future high-speed RF applications.

A New Water Film Depth Prediction Model for Pavement Surface Drainage

The prediction of the water film depth (WFD) on the road surface can help with road skid resistance research and reduce the risk associated with driving on rainy days. At present, there are many empirical and analytical models based on drainage length, slope, rainfall intensity and other parameters. Considering the influence of road surface runoff and starting from the Reynolds number formula of road surface water flow, a new road surface WFD calculation formula that considers the movement state of laminar water flow is derived. The results show that the changing trends of various parameters in the prediction model (drainage length, rainfall intensity, road slope) affecting WFD are consistent with those of the existing model. It is also found that the initial water film depth, initial speed of rainwater, and rainfall angle have little impact on WFD. The predicted value of the model has a suitable matching degree compared with the classical empirical model, which provides a new approach to the prediction of road water film depth.

Outcomes of mobilization in the first hour following uniportal video-assisted thoracoscopic surgery for primary spontaneous pneumothorax.

Although primary spontaneous pneumothorax is a common disease in young adults, each thoracic surgery department performs different procedures for its management. The optimal time of postoperative mobilization is not yet standardized in lung surgery. This study included male patients with a primary spontaneous pneumothorax who underwent wedge resection of the upper lobe of the lungs via uniportal video-assisted thoracoscopic surgery. Patients were encouraged to stand up within the first postoperative hour. Mobilization was defined as standing and walking at least 100 m from the bed. If orthostatic hypotension occurred, mobilization was postponed for 30 min. Immediately after surgery, intravenous fluids were discontinued, and patients were instructed to drink water. The analgesic treatment needs, length of hospitalization, drainage, and discharge times were recorded. A total of 43 patients were operated on by the same surgeon. All operations were ended with uniportal video-assisted thoracoscopic surgery. Wedge resection is most commonly indicated for recurrent ipsilateral pneumothorax. Patients walked 345 (range: 150-510) m on the department corridor following bed rest. Paracetamol (2 g) and dexketoprofen (100 mg) were intravenously administered as postoperative analgesia to 76.7% of patients. Narcotic drugs were not needed. Mobilization was recommended in the first hour following uniportal video-assisted thoracoscopic surgery for primary spontaneous pneumothorax.

Mapping Groundwater Resource using Multispectral Sentinel 2 and Fuzzy Logic method, Case Study: Salafchegan, Qom, Iran

Groundwater is one of the essential freshwater sources for human consumption, with the highest reserves of fresh water on earth after glaciers and glaciers. Conservation and maintenance of groundwater quality in a large area require an overview of the status and potential of groundwater resources in that area, which can be applied to potential areas using remote sensing technology. In this study, after extracting the factors influencing the formation of groundwater aquifers from the Sentinel satellite image, appropriate information layers were prepared and integrated into the ArcGIS using different fuzzy operators and potential maps prepared with the location of groundwater wells. The area was validated. The results of combining slope layers, slope direction, lithology, drainage length density, lineament length density, lineament buffer, drainage buffer, and vegetation in the area showed that fuzzy multiplication and gamma operators could be used as suitable operators for Introducing information layers to identify groundwater potential in the area. Also, using the gamma numbers 0.1 gave better results than larger gamma numbers. The research results showed that 15.9% of the studied area has good and very good potential for the presence of underground water in the production map using the fuzzy gamma with gamma 0.1 method. Also, this map was validated by 70.1% of water wells in the region. The normalized ratio of accuracy to validity in the final production model with this method was estimated to be 54%, which is entirely acceptable compared to other methods.