Single-stage Operation Research Articles

A CSI-Fed PMSM Drive System With Single-Stage Operation for Extended Constant-Torque Range

A CSI-Fed PMSM Drive System With Single-Stage Operation for Extended Constant-Torque Range

Optimizing virus filtration for continuous processing using serial filtration at high area ratio.

Compared to batch operation, continuous bioprocessing can offer numerous advantages, including increased productivity, improved process control, reduced footprint, and increased flexibility. However, integration of traditional batch operations into a connected process can be challenging. In contrast to batch operations run at constant pressure or high flux, virus filtration in continuous processes may be operated at very low flux. This change in operating conditions may reduce the viral retention performance of the filter which has inhibited adoption of truly continuous virus filtration. To overcome this limitation, a novel approach is described that utilizes serial virus filtration, with a high area ratio between first to second stage filters, to achieve virus retention targets. In this study, virus filters were operated continuously (except for planned process interruptions) for 200 h in a serial configuration at a first to second stage filter area ratio of 13:1 and at a first stage flux of 5 L/m2/h. While the minute virus of mice (MVM) retention performance of the first stage filter was about 4 log reduction value (LRV), there was no virus detected in the second stage filtrate, translating to an MVM LRV across the filtration train of ≥6.7. The second stage filter was the dominant flow resistance at the start of the run but, as it was protected from foulants by the first stage filter, it suffered minimal fouling and the life of the filter train was controlled by the first stage. A theoretical case study projected that continuous virus filtration using serial configuration at high area ratio would have about 30% longer filter changeout time, 14% higher productivity, and virus retention nearly sixLRV greater than single stage operation. The findings of this research are expected to provide valuable insights into optimizing virus filtration in continuous bioprocessing.

Interrupted aortic arch with bicuspid aortic valve stenosis in an adult: A case report.

The case report describes a rare instance of an interrupted aortic arch (IAA) with bicuspid aortic valve stenosis in a 48-year-old male patient with a one-year history of refractory hypertension, chest pain, and numbness in the upper and lower extremities. A single-stage operation was performed through a midline sternotomy, involving aortic valve replacement and posterior pericardial ascending-to-descending aortic bypass. Managing such rare conditions can be challenging due to limited guidelines, no meaningful conclusion may be made as to whether single-stage or two-stage repair is superior. Final management decision in adult patients with IAA must be individualized and depend on the associated malformations, patient preference, and precise anatomy imaging. The single-stage posterior pericardial ascending-to-descending aortic bypass appears as a safe surgical method in such cases when concomitant cardiac procedures are indicated.

Effect of inlet distortion on internal flow and performance of a contra-rotating fan operating with single-stage impeller

To establish a theoretical foundation for the rational selection of contra-rotating fans operating with a single-stage impeller under inlet distortion. Unsteady numerical simulations were conducted using the SST k-ω turbulence model to analyze the airflow fields, respectively, for the single-stage operation of front impeller (SSOFI) and the single-stage operation of rear impeller (SSORI) of the fan. The internal flow characteristics with single-stage operation under both distorted inlet condition (DIC) and uniform inlet condition (UIC) were studied. Furthermore, a comparison of the performance parameters of the fan, including total pressure and total pressure efficiency, was conducted. Focusing on the SSOFI with satisfactory operational performance of the contra-rotating fan, this study aims to reveal the propagation of inlet distortion inside the fan and reveal the influence mechanisms of inlet distortions on the performance of the fan. The results indicate that the impact of inlet distortion on the flow field is primarily concentrated in the upstream area of the front-stage impeller for SSOFI. However, the flow disturbance from the exit of the front-stage impeller to the diffuser is relatively minimal. For SSORI, the inlet distortion exacerbates the adverse effect of the front stage impeller as the front guide vane on the flow inside the rear stage impeller. The entropy loss in the two-stage impellers is significantly higher than that under the uniform inlet condition, and the turbulence level in the diffuser is intensified. While the efficiency of the fan is significantly influenced by the inlet condition and operating stages, their impact on the total pressure is small. Specifically, under uniform inlet conditions, the total pressure efficiency for SSOFI exceeds that of SSORI by 4.9 %, whereas the difference rises to 11 % under inlet distortion condition.

Power Flow Analysis Using Fuzzy for Single Phase Transformer Less PV System Connected with a Nine-Level Converter

Power electronics technology advancements and growing environmental concerns worldwide have made photovoltaic (PV) systems more visible in distributed generation systems. Photovoltaics, or solar PV, is an important component of solar energy for generating electricity. Grid-connected inverters must be able to regulate the amount of power they inject into the grid, track maximum power points, be highly efficient, and inject currents into the grid with minimal harmonic distortion. Two step-down converters were used to construct an inverter without a single-phase transformer. This study investigates two multi-sequence inverter types that use different voltages and are based on single-phase grid-connected photovoltaic (PV) technology. A new nine-level grid-connected transformer-less photovoltaic converter was proposed in this study. MATLAB was used to construct the complicated FFT simulation using fuzzy logic controls. Analyzing efficiency through simulation in order to enhance efficiency. This work aims to replace PI controllers with fuzzy controlled systems so that single-stage operation can be improved with reduced switches in an economic manner. An improvement of 10% over the existing system is achieved by implementing fuzzy computing.

Bilateral Wilms tumor: 10-year experience from a single center in China.

Nephron sparing surgery (NSS) had become the main surgical treatment for bilateral nephroblastoma. But it remained a challenge for surgeons to balance the dilemma between complete tumor resection to reduce tumor recurrence and renal parenchyma preservation to reduce end-stage renal disease (ESRD). In this study, we summarized our clinical experience for bilateral Wilms tumors managed in our center and evaluated the influence of different surgical approaches on prognosis. The clinical data of patients with bilateral Wilms tumor in our hospital from January 2010 to December 2020 were retrospectively analyzed, and the clinical symptoms, surgical approaches and prognosis of the disease were summarized. We reviewed medical records of 16 patients, including 13 (81.3%) girls and 3 (18.7%) boys. The mean age of the patients was 17.88±11.65 months (range, 6-42 months). Five patients presented with hypertension and two presented with hemihypertrophy. Fifteen cases had synchronous tumors, while only one patient had metachronous bilateral lesions. Thirteen patients received neoadjuvant chemotherapy and only 8 kidneys (30.8%) responded to chemotherapy. Two patients gave up surgery, and the other fourteen patients underwent radical resection, of which 2 patients only underwent unilateral radical nephrectomy (RN); 7 and 5 patients underwent single-stage and two-stage operation for bilateral lesions, respectively. In all surgical patients, RN was performed on 5 kidneys, and NSS was performed on 21 kidneys. The positive margins after NSS were found in 6 kidneys (35.3%). After a median follow-up period of 26.3 months, local tumor recurrence and renal insufficiency occurred in two and one patients. The 5-year overall and event-free survival rates were 78.1% and 58.6%, respectively. In univariable analysis, the survival rate in the initial chemotherapy group (92.3%) was significantly higher than that in the initial surgery group (33.3%) (P=0.048), whereas positive margin and staged operation (P>0.05) appeared not significantly associated with overall survival. The proportion of tumor reduction after preoperative chemotherapy is relatively low for bilateral Wilms tumor, but preoperative chemotherapy could improve overall survival. NSS is recommended for bilateral Wilms tumor, and the customized procedure can be selected according to the location and anatomical features of tumor.

A New Five-Level Switched-Capacitor-Based Transformer-less Common-Grounded Grid-Tied Inverter

This paper proposes a new switched-capacitor grid-tied inverter. The proposed topology can eliminate leakage current using a common-grounded strategy. Also, the proposed topology generates a five-level output voltage waveform using a single input dc source with a voltage boosting factor of 2. This structure uses six power switches, two diodes, and two self-balanced capacitors. The proposed inverter has some advantages such as a common-grounded feature, eliminated leakage current, and voltage boosting feature with single-stage energy conversion operation. Also, the proposed topology can support both active and reactive powers and generate a perfect sinusoidal output current injected into the grid. Also, to control both active and reactive powers an efficient control strategy is applied. To generate the precise gate pulses for the power switches, the introduced efficient control strategy is applied. Also, comprehensive discussions on the operating modes of the proposed inverter, Capacitor charging current analysis, the control technique, and design considerations are presented. To show the advantages and differences of the proposed inverter with some other recently presented switched-capacitor-based grid-tied inverters a comparison study is considered. Finally, to validate the performance and feasibility of the proposed inverter, various experimental results based on a 620 W experimental prototype are presented.

The Fate of Conventional Elephant Trunk in the Frozen Elephant Trunk Era.

Conventional elephant trunk (cET) and frozen elephant trunk (FET) are two distinct approaches to the surgical treatment of thoracic aortic aneurysms and dissections. With the advent and growing uptake of endovascular technologies, FET is becoming increasingly popular for its potential to be performed as a single-stage operation with better aortic remodeling and less risk of graft kinking than the traditional two-stage cET procedure. However, FET has been associated with a higher risk of spinal cord ischemia and its use in patients with connective tissue disorder remains controversial. The current review aimed to reflect on recent evidence surrounding the application of cET and FET to different types of aortic pathology in both acute and elective settings. Another scope of this review was to compare the characteristics of the currently available FET commercial devices on the global market. Our findings highlight that when the pathology is confined to the proximal descending aorta, such as in Dsine, intervention is often single-staged and false lumen (FL) thrombosis is achieved with good effect. FET remains limited by spinal cord injury and applicability in patients with connective tissue disorder, although some groups have started to circumvent associated complications, likely due to growing surgical expertise. Many other aortic diseases do require second-stage intervention, and even in these cases, there appears to be lower in-hospital mortality when using FET over cET. This is possibly due to the higher rate of endovascular completion facilitated by the completed landing zones created during FET. FET is trending toward becoming the universal treatment modality for extending repair to the descending aorta.

Toward Efficient Palmprint Feature Extraction by Learning a Single-Layer Convolution Network.

In this article, we propose a collaborative palmprint-specific binary feature learning method and a compact network consisting of a single convolution layer for efficient palmprint feature extraction. Unlike most existing palmprint feature learning methods, such as deep-learning, which usually ignore the inherent characteristics of palmprints and learn features from raw pixels of a massive number of labeled samples, palmprint-specific information, such as the direction and edge of patterns, is characterized by forming two kinds of ordinal measure vectors (OMVs). Then, collaborative binary feature codes are jointly learned by projecting double OMVs into complementary feature spaces in an unsupervised manner. Furthermore, the elements of feature projection functions are integrated into OMV extraction filters to obtain a collection of cascaded convolution templates that form a single-layer convolution network (SLCN) to efficiently obtain the binary feature codes of a new palmprint image within a single-stage convolution operation. Particularly, our proposed method can easily be extended to a general version that can efficiently perform feature extraction with more than two types of OMVs. Experimental results on five benchmark databases show that our proposed method achieves very promising feature extraction efficiency for palmprint recognition.

EGS P27 Twice Recurrent Gallstone Ileus Requiring 3 Laparotomies – A Case Report

Abstract Background Gallstone ileus is a well-known and not an uncommon complication of gall stone disease, with standard management being an enterotomy and extraction of the obstructing gallstone with management of the gallbladder and the billio-enteric fistula being deferred to an interval procedure if indicated. Recurrent gallstone ileus are not unheard of, but are quite rare and are the reason cited by the proponents of a single stage procedure. While a single stage procedure is possible - involving an enterotomy as well as a challenging cholecystectomy and the management and closure of a duodenal fistula – more commonly than not it is not performed. Methods Twice recurrent gallstone ileus is extremely rare and on performing a literature review only 1 published case report has been identified. Here we present the case of an 87-year-old Caucasian female, presenting with 3 incidences of gall stone ileus in a 30 day period requiring 3 laparotomies. Initial presentation to our institution was in November 2022 with a CT proven localised Gallbladder perforation. The first presentation with gallstone ileus was on 21/03/2023 with symptoms of bowel obstruction and CT proven obstructing 23mm gallstone 8 cm from the ileocaecal valve as well as pneumobillia and two other stones in the gallbladder. Results The index laparotomy was performed and no transition point was found, and bowel run-through from DJ to ICV revealed no intraluminal gall stones and the caecum was full of fluid. The gallstone had passed into the colon spontaneously and no enterotomy was performed. Two subsequent laparotomies were required due to CT proven incidence of recurrent Gallstone ileus on 30/03/2023 and 20/4/2023, were enterotomies were performed and the obstructing stones extracted each time. An informed decision not to tackle the gallbladder and the duodenal fistula was taken by a consensus of 3 consultant surgeons due to the frailty of our patient. Conclusions Our patient made a meaningful recovery after developing an entero-cutaneous fistula that resolved with conservative management and was discharged home on 15/05/2023. While our patient's frailty and previous gallbladder perforation made the decision not proceed with a cholecystectomy and repair of the duodenal fistula a straightforward one, the incidence of twice recurrent gallstone ileus in the span of a month raises questions as to whether other techniques should be considered in a more fit patient such as a single stage operation or a Cholecystolithotomy.

Lumbar lordosis restoration by minimally invasive short-segment fusion with anterior column realignment for adult spinal deformity: minimum 2-year follow-up.

The efficacy of anterior column realignment (ACR) remains relatively unclear, possibly because some safety concerns have limited its adoption and extensive evaluation. The authors aimed to study whether a minimally invasive surgery (MIS) triad consisting of ACR, lateral lumbar interbody fusion, and percutaneous pedicle screw fixation in a select group of adult spinal deformity (ASD) patients helps shorten fusion length without compromising clinical and radiographic outcomes over a minimum 2-year follow-up period. A series of 61 ASD patients (mean age 72.8 years) with pelvic incidence (PI) - lumbar lordosis (LL) (PI-LL) mismatch > 10° underwent the short-segment MIS triad (mean fusion length 3.0 levels) as a single-stage operation with a mean operative time and estimated blood loss of 157 minutes and 127 mL, respectively. Exclusion criteria were 1) thoracic scoliosis as the main deformity, 2) thoracolumbar junction kyphosis > 25°, 3) ankylosed facet joints, and 4) previous spinal fusion surgery. Seven patients, who needed fusion to be extended to S1, underwent mini-open transforaminal lumbar interbody fusion at L5-S1. The segmental disc angle at the ACR level more than quintupled, averaging from 2.9° preoperatively to 18.9° at the latest follow-up (p < 0.0001). LL, in turn, nearly doubled from 17.0° to 32.8° (p < 0.0001) and PI-LL decreased by nearly half from 28.8° to 13.2° (p < 0.0001). At the same time, other spinopelvic deformity parameters as well as Oswestry Disability Index (ODI) scores significantly improved. Patients were divided into two groups at the latest postoperative evaluation: 36 patients whose PI-LL improved to < 10° and 25 patients who maintained a PI-LL mismatch > 10°. Binary logistic regression revealed preoperative PI-LL mismatch as the only factor that significantly influenced this dichotomous separation postoperatively. Receiver operating characteristic curve analysis identified the critical preoperative mismatch of 26.4° with 68% sensitivity and 84% specificity. Despite this different radiographic consequence, the two groups had an equally successful clinical outcome with no significant difference in ODI scores. As long as the ASD characteristics are consistent with the authors' exclusion criteria, the short-segment MIS triad served as an excellent surgical option in the patients with preoperative PI-LL mismatch < 26.4°, but the technique also worked well even in those with a mismatch > 26.4°, although ideal spinopelvic alignment targets were not necessarily achieved in these patients.

A case of Aspergillus empyema successfully treated by a single-stage cavernostomy and a covering procedure using both fat pad and muscle flap

BackgroundAspergillus empyema due to rupture of a pulmonary cavity including an aspergilloma is a serious condition especially in immunocompromised patients with various co-morbidities. Open window thoracotomy is usually performed to control infection, followed by secondary myoplasty. However, such a two-stage strategy requires long treatment period and accompanies the invasiveness of multiple operations. On the other hand, single-stage surgery is minimally invasive, and patients’ activities of daily living are less impaired. We present a single-stage surgery consisting of cavernostomy and a covering procedure using both fat pad and muscle flap.Case presentationA 28-year-old man taking 20 mg of prednisone for rheumatoid arthritis presented with right-sided chest pain. A chest computed tomography and thoracoscopy showed a perforated pulmonary cavity including an aspergilloma in the right apex of the lung. Antifungal medication was started, but the thoracic and pulmonary cavities persisted. Therefore, surgical intervention was indicated, and considering the patient’s general condition and anticipated length of treatment period, we decided to conduct a single-stage operation. A cavernostomy was performed on the ruptured cavity. To reliably close the air leak and to occlude the air space to prevent recurrence of infection, a subcutaneous free fat pad was harvested and filled into the cavity. A pedicled latissimus dorsi muscle flap was further introduced into the thoracic space to cover the fat pad. There was no postoperative air leak and the patient was discharged on postoperative day 20 with no adverse events and no limitation of movement in the arm. A series of post-operative CT showed that the pedicled latissimus dorsi muscle flap and free fat pad gradually shrank with lung re-expansion, but they were still present and filled the thoracic and pulmonary cavities 10 months after surgery.ConclusionA single-stage surgery consisting of cavernostomy and a covering procedure using both a fat pad and muscle flap was effective in sealing air leaks, filling the air space, and preventing recurrence of infection. The fat pad and muscle flap appear to have worked in a complementary way.

Pressure leach of β-spodumene with carbonic acid: Weak acid process for extraction of lithium

This contribution develops a process for recovering lithium from β-spodumene by sequential pressure leach with solutions of carbonic acid, as a replacement for digestion of β-spodumene with concentrated sulfuric acid. Six sequential steps, each operated at 200 °C and 100 bar for 1 h, retrieve 75 % of lithium from the initial feed material. This compares with a 12.6 % Li recovery from a single-stage (batch) operation. We develop both the thermodynamic and mass-transfer models of the leach process and argue that the lithium extraction is mass-transfer controlled. The underlying mechanism involves: (i) near-instantaneous ion exchange between H+ for Li+ at the onset of the digestion; (ii) direct formation of amorphous Li-depleted rinds; (iii) precipitation of secondary minerals, boehmite (AlO(OH)) and skin-forming amorphous silica (SiO2), the latter only in the batch operation; (iv) counter-current diffusion of H+ and Li+ through the surface layer (surface layer = depleted sublayer + precipitation sublayer); (v) dissolution of the surface layer at the solid-solution interface, through the reactions with water. The evidence comes from the near-proportionality between the lithium recovery and mass of dissolved β-spodumene, no detection of keatite-HAlSi2O6, particle morphology, precipitation of amorphous skins of SiO2 decorated with boehmite specks observed by electron microscopy and predicted from thermodynamic modelling as well as from a mass-transfer analysis of the Li-recovery rates. Direct observations confirm the existence of a three-phase reacting system, as predicted from thermodynamic calculations, with the absence of a supercritical fluid phase. Lithium recoveries, of at least 28 % in a single step, are attainable, but only for long contact time of 48 h. Digestion lasting hundreds of hours is needed for the batch process to reach Li extraction corresponding to that of the sequential leach. The challenges for industrial implementation of the process comprise recycling of large amounts of water, avoiding the precipitation of silica that forms rinds, accelerating the hydrolysis of Li-depleted sublayer, concentrating the dilute solutions of Li+ and overcoming hesitance of industry to consider high-pressure treatment.

A Family of Single-Phase Single-Stage Boost Inverters

H-bridge inverter is a common topology used for single-phase applications. Due to its limited voltage gain, a two-stage power conversion with a front-end dc-dc converter is usually adopted to accommodate the low dc source voltage. Recently, single-stage boost inverters are gaining significant interest due to their higher power efficiency and compactness. This paper presents a family of boost inverters with continuous dc source current. By the incorporation of merely a power switch and a boost inductor to the first leg of H-bridge, voltage-boosting and 3-level generation can be simultaneously achieved within a single-stage operation. All potential topologies using the same number of components are derived. An extension to generate five voltage levels with voltage gain enhancement is also proposed. The operation of the proposed boost inverters is thoroughly analyzed. Simulation and experimental results are presented for verification.

Gallstone Ileus With Persistent Cholelithiasis and Choledocholithiasis.

Gallstone ileus is an uncommon but well-described occurrence in general surgery. However, discrepancy regarding optimal surgical management with 1 or 2 stage operation is still debated. This case report presents a 73-year-old woman who presented to the emergency department (ED) with a small bowel obstruction due to a gallstone lodged in a portion of the proximal ileum. The patient was also noted to have persistent cholelithiasis and cholecystoduodenal fistula. A single-stage surgery involving enterolithotomy, cholecystectomy, fistula repair, and cholangioscopy was performed. The patient progressed well and was discharged home without recurrent symptoms. Therefore, in a hemodynamically stable patient with persistent cholelithiasis or choledocholithiasis, it is reasonable to perform a definitive single-stage operation.

One-stage reconstruction using a fibula osteocutaneous free flap and an anterolateral thigh free flap for an extensive composite defect after en bloc resection of squamous cell carcinoma on the mouth floor, mandible, and anterior neck: A CARE-compliant case report.

Although regional metastasis to the lymph nodes is common in advanced oral cancer, extensive local invasion into surrounding structures such as the mandible, skin and soft tissue of the neck, and masticator space is relatively rare. Sometimes surgical treatment cannot be performed and only palliative chemotherapy and radiation therapy are offered to preserve the quality of life of patients with advanced oral cancer. Nevertheless, the surgical resection of tumors remains the most effective treatment. This study presents a case of aggressive mouth floor cancer in which extensive composite defects on the mouth floor, oral mucosa, mandible, skin and soft tissue of the neck caused by tumor resection were reconstructed. A 66-year-old man and a 65-year-old man with no significant personal or family history visited our clinic due to a large and multiple masses on the floor of the mouth and both sides of the neck. Histopathological evaluation of the biopsy specimen revealed squamous cell carcinoma. A fibula osteocutaneous free flap and customized titanium plate were used for the intraoral lining. Mandibular reconstruction was performed using a 3D-printed bone model, and an anterolateral thigh free flap was used to resurface the anterior of the neck. Reconstruction using this method was successful, and excellent functional and aesthetic outcomes were achieved without cancer recurrence. This study show that the reconstruction of extensive composite defects of the oral mucosa, mandible, and neck soft tissue following surgical resection of mouth floor cancer can be performed in a single-stage operation. Through a single-stage reconstruction, both excellent functional aspects without cancer recurrence and satisfactory aesthetic outcomes can be obtained.

A study of outcome of ossiculoplasty using autologous cartilage, refashioned incus, and polytetrafluoroethylene (Teflon) prosthesis in patients of chronic suppurative otitis media

AimTo find out the mean air conduction thresholds (ACT) and air–bone gap (ABG) closure across the treatment groups at the end of 3 and 6 months of follow-up.Material and methodsSixty patients diagnosed with COM with conductive hearing loss were included in the study. Air conduction threshold (ACT) and air–bone gap were calculated and recorded pre-operatively. Surgery was done with clearance of disease followed by reconstruction of hearing in single-stage operation using autologous conchal cartilage, refashioned incus, and polytetrafluoroethylene (Teflon) prosthesis (PORP, TORP) depending upon the intraoperative findings during surgery. Patients were followed for up to 6 months for assessing the hearing outcome in terms of the mean air conduction threshold and mean air–bone gap closure for each group separately.ResultsThe outcome of each ossiculoplasty material was calculated in terms of mean air conduction threshold and mean AB gap closure. Preoperative and postoperative air conduction threshold (ACT) at 3 months and 6 months follow-up of each group was as follows: for the autologous conchal cartilage group, 41.3 (± SD 6.69), 29.2 (± SD 5.39), and 21 (± SD 4.66); for autologous refashioned incus group, 40.4 (± SD 5.43), 28.4 (± SD 6.73), and 20.8 (± SD 4.33); for the Teflon PORP group, 42.9 (± SD 5.68), 31.4 (± SD 6.86), and 34.9 (± SD 6.37); and for the Teflon TORP group, 43.1 (± SD 5.40), 32.5 (± SD 5.91), and 36.2 (± SD 5.31). The mean air–bone gap preoperatively and postoperatively at 3 months and 6 months respectively were as follows: for autologous conchal cartilage, 40.6 (± SD 4.57), 23.7 (± SD 4.48), and 20 (± SD 5.28); for autologous refashioned incus, 39.3(± SD 4.92), 21.9 (± SD 5.61), and 19.4 (± SD 5.82); for Teflon PORP 43.0 (± SD 4.48), 32.8 (± SD 4.84), and 36.3 (± SD 5.56); and for Teflon TORP, 44.5 (± SD 5.56), 33.2 (± SD 5.53), and 35.2 (± SD 5.10).ConclusionThe hearing outcome of ossiculoplasty varies with the type of ossiculoplasty material used. Most favorable results were obtained with refashioned autologous incus followed by autologous conchal cartilage. Teflon prosthesis has a significant improvement in hearing outcomes although the results are less favorable.

Methods to increase the effectiveness of cytoreductive surgical interventions in patients with complicated disseminated tumors of the abdominal cavity and pelvis

The expediency of performing two-stage cytoreductive interventions in patients with complicated disseminated tumors of the abdominal cavity and pelvis is presented. Ninety-two patients with complicated disseminated tumors of the abdominal cavity and pelvis were examined into two groups. The main group consisted of 33 patients who received surgical treatment by two-stage cytoreductive surgery. The control group included 59 patients who underwent single-stage cytoreductive operations. In both groups, life-threatening complications were dominated by primary tumor necrosis (main group, n = 15; control group, n = 31) and impaired intestinal patency (main group, n = 12; control group, n = 16, respectively). The average Charlson comorbidity index was 7.85 1.37 and 7.53 1.5 points, respectively. Anesthetic risk of grades IIIIV according to the classification of the American Society of Anesthesiologists was detected in 23 (69.7%) and 45 (76.27%) patients of the main and control groups, respectively. Functional status of 23 points on the Eastern Cooperative Oncological Group was established in 23 (69.7%) and 46 (77.9%) patients of the main and control groups, respectively. The peritoneal carcinomatosis index was significantly higher in the main group (13.1 6 vs 9.9 4.8 points) than in the control group (p = 0.012). A comparative analysis of the results obtained in the treatment of the main and control groups demonstrated that the two-stage cytoreductive surgical interventions can reduce the frequency of postoperative complications, primarily ClavienDindo grades IIIIV from 40.7 to 18.2% (p = 0.049) and mortality from 16.9% to 9.1% (p = 0.468) and increase the frequency of achieving complete cytoreduction from 49.1% to 90.9% (p = 0.002) and the frequency of intraperitoneal hyperthermic chemoperfusion from 40.7 to 93.9% (p 0.001). Thus, two-stage cytoreductive surgical interventions are a safe and effective technique in the surgical treatment of complicated disseminated tumors of the abdominal cavity and pelvis.

Research of Continuous Delta-Sigma Analog-to-Digital Converter for Bio-Electricity Signal Acquisition

In this paper, a continuous delta-sigma analog-to-digital converter with a low power, single-ring, third-order mixed integrator for bio-electricity signal acquisition is proposed. For the trade-off between low power consumption and high resolution, the Active-RC integrator is used in the first-order of the third-order feedforward modulator and the Gm-C integrator with improved linearity is adopted for the second and third order integrators. Because of the infinite resistance provided by the Gm-C integrator, the first-order integrator can replace the traditional second-order operational transconductance amplifier (OTA) with a single-stage OTA operating in the weak invert region to achieve low power consumption and ensure the output swing of the first-order integrator. The structure of cascade-of-integrators with feedforward (CIFF) can scale the output voltage values of three integrators and reduce the requirement of linearity of the Gm-C integrator, to reduce the design difficulty of the Gm-C integrator. In addition, the linearity of the second and third-order Gm-C integrator is improved by using the auxiliary difference pair OTA with source-level negative feedback. Therefore, the matching between the circuit structure and the model coefficients is improved significantly.

Single-institution comparative analysis for odontoid resection: posterior transaxis versus anterior transnasal approach.

The resection of an upwardly migrated odontoid is most widely performed via an anterior endoscopic endonasal approach after the addition of posterior occipitocervical instrumentation. In patients with craniovertebral junction (CVJ) anomalies like basilar invagination (BI), surgery is usually achieved in two separate stages. However, the authors have recently introduced a novel posterior transaxis approach in which all the therapeutic goals of the surgery can be safely and effectively accomplished in a single-stage procedure. The aim of the current study was to compare the widely used anterior and the recently introduced posterior approaches on the basis of objective clinical results in patients who underwent odontoid resection for BI. Patients with BI who had undergone odontoid resection were retrospectively reviewed in two groups. The first group (n = 7) consisted of patients who underwent anterior odontoidectomy via the standard anterior transnasal route, and the second group (n = 6) included patients in whom the novel transaxis approach was performed. Patient characteristics, neurological conditions, and modified Rankin Scale (mRS) scores at admission were evaluated. Operative time, changes in intraoperative neurophysiological monitoring, blood loss during surgery, odontoid resection rate, postoperative complications, and mortality were compared between the patient groups. Data were retrospectively reviewed for 13 patients who underwent odontoid resection, posterior CVJ decompression, and occipitocervical instrumentation at the Ankara University School of Medicine Department of Neurosurgery between 2009 and 2022. In the first group (n = 7), patients who underwent anterior odontoidectomy via the standard endonasal route, two serious complications were observed, pneumocephaly and basilar artery injury. In the second group (n = 6), patients in whom the novel transaxis approach was performed, only one complication was observed, occipital plate malposition. This study represents the results of what is to the authors' knowledge the first comparison of a novel approach with a widely used surgical approach to odontoid resection in patients with BI. The preliminary data support the successful utility of the transaxis approach for odontoid resection that meets all the operative therapeutic demands in a single-stage operation. Considering the diminished surgical risks and operative time, the transaxis approach may be regarded as a primary approach for the treatment of BI.