Split Function Research Articles

Robotic-assisted laparoscopic pyeloplasty for ureteropelvic junction obstruction A retrospective review of a high-volume Canadian center.

At present, there is no literature on the outcomes of robotic-assisted laparoscopic pyeloplasty (RALPyelo) in a Canadian context. Our objective was to perform a retrospective review of RALPyelo cases at a high-volume Canadian center. We performed a retrospective review of patients who underwent RALPyelo at St. Michael's Hospital, between January 2012 and May 2019. Demographics, operative details, and pre- and postoperative imaging results (ultrasounds, computed tomography [CT] scans, and diuretic renal scan [DRS ]) were recorded. Patients were excluded if at least one-year followup data was unavailable. Our primary outcome was clinical and radiologic improvement defined as 1) symptom improvement; 2) stable/improved split renal function on DRS ; and 3) either improvement in the degree of hydronephrosis on ultrasound or CT, or improved drainage time on DRS. Secondary outcomes included postoperative complications, need for diagnostic intervention, and reintervention for recurrent UPJO. A total of 156 patients underwent RALPyelo after exclusions. The median age was 42 and 66% were female. Mean followup was 2.5 years. For our primary outcome, 87% had clinical and radiologic improvement. Diagnostic investigation for possible recurrent/persistent obstruction, based on symptoms and/or imaging results, was required in 17% of cases, but only 3% required reintervention for recurrent UPJO. Accordingly, the overall treatment success was 97%. The most common postoperative complication was urinary tract infection (18%), and urine leak was seen in only 2% of patients. The results of our study compare favorably with currently reported outcomes in the literature and demonstrate the safety and high level of success of RALPyelo at a high-volume Canadian center.

Search for Neutron-to-Hidden-Neutron Oscillations in an Ultracold Neutron Beam.

Models that postulate the existence of hidden sectors address contemporary questions, such as the source of baryogenesis and the nature of dark matter. Neutron-to-hidden-neutron oscillations are among the possible mixing processes and have been tested with ultracold neutron storage and passing-through-wall experiments to set constraints on the oscillation period τ_{nn^{'}}. These searches probe the oscillations as a function of the mass splitting due to the neutron-hidden-neutron energy degeneracy. In this work, we present a new limit derived from neutron disappearance in ultracold neutron beam experiments. The overall limit, given by τ_{nn^{'}}>1 s for |δm|∈[2,69] peV(95.45% C.L.), covers the yet unexplored intermediate mass-splitting range and contributes to the ongoing research on hidden sectors.

Repositioning of Ureteropelvic Junction in Robot-assisted Laparoscopic Pyeloplasty

ObjectiveTo describe the technique of ureteropelvic junction (UPJ) repositioning in robot-assisted dismembered pyeloplasty as a modified approach during which the UPJ is brought to a new location to facilitate the anastomosis. Materials and MethodsRetrospective review of pediatric and adult cases of robot-assisted laparoscopic pyeloplasty performed between the years 2016-2022. In a select group of patients, repositioning of the UPJ was performed. Demographic data, surgical and post-surgical outcomes was compared to a group that underwent classical AH dismembered pyeloplasty. ResultsOverall, 70 patients underwent robot-assisted laparoscopic dismembered pyeloplasty and were included in the study, with 15 in the repositioning group and 55 in the AH group. The median age of patients included was 26 months (IQR 7-203). Median operative time was 140 minutes (IQR 129-192) and 170 minutes (IQR 135-207) for the repositioning and AH group, respectively. The indications for UPJ repositioning were high UPJ insertion (n=8), crossing vessel (n=5) and renal malformations (n=2). Clinical significance was shown in SFU classification and split renal function postoperatively respectively (p<0.001;p<0.01). Postoperatively, both groups showed improvement in APD and diuretic T1/2 (p=0.48). There was one case of surgical failure requiring revisional surgery in the repositioning group (6.6%) and three in the AH group (5.5%) (p>0.05). Overall, there were three cases of Clavien-Dindo Grade 3 complications, all in the AH group (Two cases of urine leak from anastomosis, one case of port side hernia). ConclusionRepositioning of the UPJ is optional in cases when the obstructed UPJ is in a suboptimal anatomical position.

Predicting estimated glomerular filtration rate after partial and radical nephrectomy based on split renal function measured by radionuclide: a large-scale retrospective study

PurposeThe purpose of this study was to develop predictive models for postoperative estimated glomerular filtration rate (eGFR) based on the split glomerular filtration rate measured by radionuclide (rGFR), as choosing radical nephrectomy (RN) or partial nephrectomy (PN) for complex renal masses requires accurate prediction of postoperative eGFR.MethodsPatients who underwent RN or PN for a single renal mass at Xijing Hospital between 2008 and 2022 were retrospectively included. Preoperative split rGFR was evaluated using technetium-99 m-diethylenetriaminepentaacetic acid (Tc-99 m DTPA) renal dynamic imaging, and the postoperative short-term (< 7 days) and long-term (3 months to 5 years) eGFRs were assessed. Linear mixed-effect models were used to predict eGFRs, with marginal R2 reflecting predictive ability.ResultsAfter excluding patients with missing follow-up eGFRs, the data of 2251 (RN: 1286, PN: 965) and 2447 (RN: 1417, PN: 1030) patients were respectively included in the long-term and short-term models. Two models were established to predict long-term eGFRs after RN (marginal R2 = 0.554) and PN (marginal R2 = 0.630), respectively. Two other models were established to predict short-term eGFRs after RN (marginal R2 = 0.692) and PN (marginal R2 = 0.656), respectively. In terms of long-term eGFRs, laparoscopic and robotic surgery were superior to open surgery in both PN and RN.ConclusionsWe developed novel tools for predicting short-term and long-term eGFRs after RN and PN based on split rGFR that can help in preoperative decision-making.

Study on Two-Dimensional Exit Pupil Expansion for Diffractive Waveguide Based on Holographic Volume Grating

Diffraction gratings are becoming a preferred option for waveguide head-mounted in–out coupling devices due to their flexible optical properties and small size and light weight. At present, diffraction waveguide coupling devices for AR head-mounted displays (HMD) have difficulties such as a long development cycle and complicated processing. In this paper, we first establish a set of two-dimensional (2D) grating ray tracing models, based on which we determine the initial architecture of the dual-region two-dimensional exit pupil expansion (2D-EPE) AR-HMD holographic waveguide diffraction system. Second, we propose a honeycomb coupled grating array and optimize the optical energy utilization and brightness uniformity of the holographic waveguide and use a custom dynamic linked library (DLL) function to implement the ray tracing of the 2D grating and add a probabilistic splitting function to the DLL, which reduces the single simulation time from 11.853 min to 1.77 min. We also propose a holographic lithography device composed of holographic optical elements (HOEs) and a method for preparing HOEs. Finally, in order to obtain the diffraction efficiency preoptimized by the above DLL for the uniformity of the exit pupil brightness and light energy utilization, we inverse design with the preparation process parameters as the optimization variables and develop the adaptable electromagnetic calculation program Holo-RCWA. Using Holo-RCWA with nondominated sorting genetic algorithm II (NSGA-II), we inverse design to obtain the process parameters satisfying the diffraction efficiency distribution, and the optimization time of the whole system is reduced from 2–3 days to 10 h. This work is of great significance for AR/VR applications.

Voiding Cystourethrogram Before Pyeloplasty: To Do or Not To Do?

To assess the incidence of concomitant vesicoureteral reflux (VUR) in unilateral cases of ureteropelvic junction obstruction(UPJO) and to identify factors that predict VUR. Files of 381 pediatric patients who underwent unilateral pyeloplasty between 2000 and 2017 were retrospectively reviewed.A total of 270 patients with available data and ≥5 years of follow-up were eligible for this study.Demographic parameters,preoperative hydronephrosis grade,renal pelvis anteroposterior diameter(APD),renal parenchymal thickness(PT),split renal functions on MAG-3 scan and VUR status were noted.The patients were divided into two groups:Those with concomitant VUR(Group I, n:24, 8.9%) and those without VUR(Group II,n:246, 91.1%). Among 270 patients(205 boys,75.9%) with a median age of 4 months(2-98),197 (72.9%)had antenatal hydronephrosis.Median follow-up was 11 years(5-22).Among 24 patients with concurrent VUR,6(25%) had Grade II VUR,whereas Grade III-V VUR was detected in 18(75%).Of these,12(50%) had ipsilateral VUR,3(12.5%) had contralateral,and 9(37.5%) had bilateral VUR.In a median 137-month follow-up,spontaneous VUR resolution was observed in 6(25%) patients,whereas 15 (62.5%) patients underwent endoscopic subureteral injection and 3(12.5%) patients ureteroneocystostomy,respectively.Preoperative APD[35.5, IQR(27.6-36.0) vs. 26.5 IQR(25.0-35.0), p=0.004] were significantly higher in Group I,whereas Group I had significantly lower PT[3.7, IQR(3.4-6.4) vs. 5.8 IQR(4.4-6.1), p=0.026].Predictive factors for concomitant VUR were presentation with febrile UTI(OR:2.769,p=0.048), PT<3.95 mm(OR:1.367,p=0.043),and APD>28.8 mm (OR:1.035,p=0.001). Our results indicated that concomitant VUR and UPJO might be detected in 1 out of every 11 patients undergoing pyeloplasty,while some type of surgical intervention for VUR was required in 75% of these patients.Thus,VCUG prior to pyeloplasty may be limited in those presenting with febrile UTI,having higher APD and lower PT on preoperative urinary ultrasonography.

Four-loop splitting functions in QCD – The gluon-to-quark case

We have computed the even-N moments N≤20 of the gluon-to-quark splitting function Pqg at the fourth order of perturbative QCD via the renormalization of off-shell operator matrix elements. Our results, derived analytically for a general gauge group, agree with all results obtained for this function so far, in particular with the lowest five moments obtained via physical cross sections. Using our new moments and all available endpoint constraints, we construct approximations for the four-loop Pqg(x) that should be sufficient for a wide range of collider-physics applications. The N3LO corrections resulting from these and the corresponding quark-quark splitting functions lead to a marked improvement of the perturbative accuracy for the scale derivative of the singlet quark distribution, with effects of 1% or less at x≳10−4 at a standard reference scale with αs=0.2.

Real-time estimation of nephron activity with a linear measurement system (RENAL-MS) predicts postoperative estimated glomerular filtration rate.

To determine whether a simple point-of-care measurement system estimating renal parenchymal volume using tools ubiquitously available could be used to replace nuclear medicine renal scintigraphy (NMRS) in current clinical practice to predict estimated glomerular filtration rate (eGFR) after nephrectomy by estimating preoperative split renal function. We performed a retrospective review of patients who underwent abdominal cross-sectional imaging (computed tomography/magnetic resonance imaging) and mercaptoacetyltriglycine (MAG3) NMRS prior to total nephrectomy at a single institution. We developed the real-time estimation of nephron activity with a linear measurement system (RENAL-MS) method of estimating postoperative renal function via the following technique: renal parenchymal volume of the removed kidney relative to the remaining kidney was estimated as the product of renal length and the average of six renal parenchymal thickness measurements. The utility of this value was compared to the utility of the split renal function measured by MAG3 for prediction of eGFR and new onset Stage 3 chronic kidney disease (CKD) at ≥90 days after nephrectomy using uni- and multivariate linear and logistic regression. A total of 57 patients met the study criteria. The median (interquartile range [IQR]) age was 69 (61-80) years. The median (IQR) pre- and postoperative eGFR was 74 (IQR 58-90) and 46 (35-62) mL/min/1.73 m2 , respectively. [Correction added on 29 December 2023, after first online publication: The data numbers in the preceding sentence have been corrected.] Correlations between actual and predicted postoperative eGFR were similar whether the RENAL-MS or NMRS methods were used, with correlation using RENAL-MS being slightly numerically but not statistically superior (R = 0.82 and 0.76; P = 0.138). Receiver operating characteristic curve analysis using logistic regression estimates incorporating age, sex, and preoperative creatinine to predict postoperative Stage 3 CKD were similar between RENAL-MS and NMRS (area under the curve 0.93 vs. 0.97). [Correction added on 29 December 2023, after first online publication: The data numbers in the preceding sentence have been corrected.] CONCLUSION: A point-of-care tool to estimate renal parenchymal volume (RENAL-MS) performed equally as well as NMRS to predict postoperative eGFR and de novo Stage 3 CKD after nephrectomy in our population, suggesting NMRS may not be necessary in this setting.

Preoperative Renal Parenchyma Volume as a Predictor of Kidney Function Following Nephrectomy of Complex Renal Masses

BackgroundThe von Hippel-Lindau disease (VHL) is a hereditary cancer syndrome with multifocal, bilateral cysts and solid tumors of the kidney. Surgical management may include multiple extirpative surgeries, which ultimately results in parenchymal volume loss and subsequent renal function decline. Recent studies have utilized parenchyma volume as an estimate of renal function prior to surgery for renal cell carcinoma; however, it is not yet validated for surgically altered kidneys with multifocal masses and complex cysts such as are present in VHL. ObjectiveWe sought to validate a magnetic resonance imaging (MRI)-based volumetric analysis with mercaptoacetyltriglycine (MAG-3) renogram and postoperative renal function. Design, setting, and participantsWe identified patients undergoing renal surgery at the National Cancer Institute from 2015 to 2020 with preoperative MRI. Renal tumors, cysts, and parenchyma of the operated kidney were segmented manually using ITK-SNAP software. Outcome measurements and statistical analysisSerum creatinine and urinalysis were assessed preoperatively, and at 3- and 12-mo follow-up time points. Estimated glomerular filtration rate (eGFR) was calculated using serum creatinine-based CKD-EPI 2021 equation. A statistical analysis was conducted on R Studio version 4.1.1. Results and limitationsPreoperative MRI scans of 113 VHL patients (56% male, median age 48 yr) were evaluated between 2015 and 2021. Twelve (10.6%) patients had a solitary kidney at the time of surgery; 59 (52%) patients had at least one previous partial nephrectomy on the renal unit. Patients had a median of three (interquartile range [IQR]: 2–5) tumors and five (IQR: 0–13) cysts per kidney on imaging. The median preoperative GFR was 70 ml/min/1.73 m2 (IQR: 58–89). Preoperative split renal function derived from MAG-3 studies and MRI split renal volume were significantly correlated (r = 0.848, p < 0.001). On the multivariable analysis, total preoperative parenchymal volume, solitary kidney, and preoperative eGFR were significant independent predictors of 12-mo eGFR. When only considering patients with two kidneys undergoing partial nephrectomy, preoperative parenchymal volume and eGFR remained significant predictors of 12-mo eGFR. ConclusionsA parenchyma volume analysis on preoperative MRI correlates well with renogram split function and can predict long-term renal function with added benefit of anatomic detail and ease of application. Patient summaryPrior to kidney surgery, it is important to understand the contribution of each kidney to overall kidney function. Nuclear medicine scans are currently used to measure split kidney function. We demonstrated that kidney volumes on preoperative magnetic resonance imaging can also be used to estimate split kidney function before surgery, while also providing essential details of tumor and kidney anatomy.

Transmission and reflection bidirectional terahertz coding metasurface based on thermally switchable materials

Metasurface, with its powerful and flexible terahertz(THz) wave manipulation capability, has become a key component of beamforming and imaging systems in the THz band. However, its practical application is limited by fixed properties and propagation mode on a single metasurface. In this paper, we propose a coding metasurface with tunable characteristics and bidirectional working modes. The complete 2π phase compensation can be realized by rotating the InSb unit according to the Pancharatnam-Berry phase concept, and eight meta-atoms are selected to regulate the wavefront of terahertz waves using phase compensation. By increasing the temperature of the InSb from 290 K to 370 K, the working frequency permits wideband coverage from 1.7 to 4.5 THz. As the temperature reaches 341.15 K, which is required for vanadium dioxide's(VO2) phase transition, the metasurface's propagation direction mode will switch from transmission to reflection. The proposed metasurface can perform beam deflecting, splitting, and focusing functions when VO2 is in a dielectric state. Meanwhile, beam deflecting, splitting, and radar scattering surface (RCS) reduction can also be achieved when VO2 is in a metallic state. Furthermore, a near-field image of the letter P is presented as verification. Numerous potential applications for the reconfigurable metasurfaces include polarization beam splitters, imaging, and terahertz switching.

Laparoscopic assisted dismembered pyeloplasty versus open pyeloplasty in UPJO with poorly function kidney in pediatrics

BackgroundThe management of UPJO with poor function kidney, less than 10%, has been the subject of debate for more than a decade. Some authors have recommended nephrectomy, while others favor renal salvage (pyeloplasty). We report our experience with laparoscopic assisted pyeloplasty in pediatric patients with poorly functioning kidneys in comparison with an open approach.Materials and methodsA retrospective study was conducted to review 65 patients who were diagnosed with hydronephrosis and had impaired renal function due to UPJO. The study was conducted in the pediatric surgery departments of Al-Azhar University Hospital and Fattouma Bourguiba University Hospital of Monastir over a period of 20 years. Limited to pediatric patients with UPJO with ≥ Grade III hydronephrosis, antero-posterior pelvic diameter ≥ 20 mm, as well as a renal function equal to or less than 10%, was corrected by laparoscopic assisted or open pyeloplasty.ResultsThere were 40 cases in group A who underwent laparoscopic assisted pyeloplasty, and 25 cases in group B who underwent open pyeloplasty. There were no complications or difficulties during the operation. The mean operative time in group A was 90 ± 12 min, while in group B, it was 120 ± 11 min. The renal assessment parameters significantly improved in both groups. In group A, the mean split renal function was 7.9 ± 1.3% and increased to 22.2 ± 6.3%. In group B, the mean split renal function was 8.1 ± 1.1% and increased to 24.2 ± 5.1%. However, the differences between both groups in terms of pre-operative and post-operative renal functions were statistically insignificant.ConclusionLaparoscopic assisted pyeloplasty is an effective treatment for patients with poorly functioning kidneys, especially those with less than 10% function. While this surgical procedure requires shorter operative times, it yields functional outcomes that are comparable to open approach.

Feasibility and Implementation of a 4D Free-Breathing Variable Density Stack-of-Stars Functional Magnetic Resonance Urography in Young Children Without Sedation.

Functional magnetic resonance urography (MRU) is well established in the diagnostic workup of urinary tract anomalies in children, providing comprehensive morphological and functional information. However, dynamic contrast-enhanced images acquired in the standard Cartesian k-space manner are prone to motion artifacts. A newly introduced 4D high spatiotemporal resolution dynamic contrast-enhanced magnetic resonance imaging based on variable density elliptical centric radial stack-of-stars sharing technique has shown improved image quality regarding motions under free breathing. The aims of this study were to implement this 4D free-breathing sequence for functional MRU and to compare its image quality and analyzability with standard breath-hold Cartesian MRU. We retrospectively evaluated all functional 4D MRU performed without general anesthesia between September 2021 and December 2022 and compared them with matched pairs (age, affected kidney, diagnosis) of standard Cartesian MRU between 2016 and 2022. Image analysis was performed by 2 radiologists independently regarding the following criteria using a 4-point Likert scale, with 4 being the best: overall image quality, diagnostic confidence, respiratory motion artifacts, as well as sharpness and contrast of aorta, kidneys, and ureters. We also measured vertical kidney motion due to respiratory motion and compared the variance for each kidney using F test. Finally, both radiologists calculated the volume, split renal volume (vDRF), split renal Patlak function (pDRF), and split renal function considering the volume and Patlak function (vpDRF) for each kidney. Values were compared using Bland-Altman plots and F test. Forty children (20 for 4D free-breathing and standard breath-hold, respectively) were enrolled. Ten children of each group were examined using feed-and-sleep technique (median age: 4D, 3.3 months; standard, 4.2 months), 10 were awake (median age: 4D, 8.9 years; standard, 8.6 years). Overall image quality, diagnostic confidence, respiratory motion artifacts, as well as sharpness and contrast of the aorta, kidneys, and ureters were rated significantly better for 4D free-breathing compared with standard breath-hold by both readers ( P ranging from <0.0001 to 0.005). Vertical kidney motion was significantly reduced in 4D free-breathing for the right and the left kidney (both P < 0.001). There was a significantly smaller variance concerning the differences between the 2 readers for vpDRF in 4D MRU ( P = 0.0003). In contrast, no significant difference could be demonstrated for volume ( P = 0.05), vDRF ( P = 0.93), and pDRF ( P = 0.14). We demonstrated the feasibility of applying a 4D free-breathing variable density stack-of-stars imaging for functional MRU in young pediatric patients with improved image quality, fewer motion artifacts, and improved functional analyzability.

Assessment of the kidney functional state prior and after partial nephrectomy for a unilateral tumor using mathematical processing of computed tomography data with contrast enhancement

Background. According to the contemporary data available contrast-enhanced computed tomography can be used to assess total and split kidney function. The Urology Clinic of the I.M. Sechenov First Moscow State Medical University, Ministry of Health of Russia (Sechenov University) utilizes mathematical processing of computed tomography data for the assessment of split kidney function.Aim. To evaluate the effect of main renal artery clamping (warm ischemia time) during partial nephrectomy for a unilateral tumor on the kidney function.Materials and methods. 33 patients of both sexes who underwent partial nephrectomy for unilateral kidney tumor were enrolled in the study. Prior to and 3–6 months after the surgery, 3D glomerular filtration rate (GFR), 3D perfusion, 3D volume of the renal parenchyma were evaluated by mathematical processing of computed tomography data with contrast enhancement. As well as that the dynamics of the total GFR (CKD-EPI equation) and total volume of the kidneys were assessed.Results. No significant changes were registered for both general functional renal parameters (creatinine level, total GFR, total volume of functioning renal parenchyma) and split 3D GFR. There were significant differences in 3D perfusion and kidney parenchyma volume prior and after partial nephrectomy.Conclusion. The results of the research highlight good reserve capacity the kidneys after partial nephrectomy with main renal artery clamping. The evidence that the non-operated kidney takes over the function of the resected kidney is based on the fact that there is an increase in its perfusion and volume of the kidney in the postoperative period. This state can also be regarded as a redistribution of functional loads between the kidneys, which is an adaptive mechanism in the postoperative period.

Laser ureteroscopic endopyelotomy efficacy in pyeloureteral junction stenosis

Introduction. Pyeloureteral junction stenosis (PUJS) is a condition that affects urinary drainage at level of the renal pelvis and upper ureter. It is found in approximately 1 in 500 newborns, with a higher prevalence in males (2:1 ratio). PUJS is the main cause of congenital hydronephrosis and can also be caused by other specific pathologies. Endoscopic management is the primary treatment for PUJS, particularly in cases of aperistaltic and &lt;2cm intrinsic ureteral stenosis without aberrant vessels. Aim of the study. Efficacy assessment of endoscopic retrograde incision of PUJS for urinary drainage recovery and duration of postoperatory effect. Material and methods. 5 patients were operated, from November 2022 to February 2023. Each patient has been operated by using retrograde LASER endopyelotomy method. There were excluded patients with extrinsic ureteral obstruction, defected segment more than 2 cm, massive hydronephrosis, split renal function &lt;20%, tumor in the obstruction area, high ureteral insertion, patients &lt;18 years of age. Mean follow-up time of patients is 8 weeks. Results. One month after intervention patients were recalled for investigations. There were observed way more better results in the patients with grade 1 hydronephrosis than those with grade 2 (p = 0.002). All patients at 3-month postoperative follow-up reported resolution of symptoms. Conclusions. Efficacy of LASER endopyelotomy is 99.9% in first months of the follow-up, after double J stent extraction. More follow-up time and patients are required to present more statistically significant results.

A Fully Packaged Wideband Bandpass Power Divider Based on Four-Port Common-Mode Network

This brief describes a generalized method to realize an in-phase power splitter based on a four-port common-mode network (CMN). By enforcing one of the four ports open-or short-circuited, a three-port network with in-phase property and equal power division at two output ports is presented. A specific CMN consisting of two identical coupled-line sections is discussed and applied to the design of a wideband power divider with bandpass frequency response. The converted circuit can not only achieve the function of equal power splitting, but also flexibly allows for the control of equal-ripple bandwidth and in-band return loss (RL) level. Furthermore, the reflection coefficients and isolation of two output ports could be ideally enhanced by installing the synthesized lumped resistors. To confirm the design concept, a fully packaged wideband power divider working at 2.0 GHz with the fractional bandwidth (FBW) of 105% has been designed and fabricated using multilayer liquid crystal polymer (LCP) circuit technology. Final measured results, well agreeing with the simulated ones, exhibit wideband bandpass response, high port-to-port isolation, and port matching condition, as well as good in-band magnitude and phase difference.

The celestial chiral algebra of self-dual gravity on Eguchi-Hanson space

We consider the twistor description of classical self-dual Einstein gravity in the presence of a defect operator wrapping a certain ℂℙ1. The backreaction of this defect deforms the flat twistor space to that of Eguchi-Hanson space. We show that the celestial chiral algebra of self-dual gravity on the Eguchi-Hanson background is likewise deformed to become the loop algebra of a certain scaling limit of the family of W(μ)-algebras, where the scaling limit is controlled by the radius of the Eguchi-Hanson core. We construct this algebra by computing the Poisson algebra of holomorphic functions on the deformed twistor space, and check this result with a space-time calculation of the leading contribution to the gravitational splitting function. The loop algebra of a general W(μ)-algebra (away from the scaling limit) similarly arises as the celestial chiral algebra of Moyal-deformed self-dual gravity on Eguchi-Hanson space. We also obtain corresponding results for self-dual Yang-Mills.

The Role of Renal Parenchyma to Hydronephrosis Area Ratio (PHAR) in Evaluation of Ureteropelvic Junction Obstruction in Children

Background The cortex/ pelvis ratio or parenchymal to pelvicalyceal area ratio can help initial evaluation and follow up of the children with uretropelvic junction obstruction as simple modality using the cut off which is 1.6 (pelvis/ cortex) ratio. There are many studies evaluating the various preoperative parameters which influence the post-operative outcomes after pyeloplasty. Practically there are many ultrasound parameters in the post-operative period which indicate the change in renal function. So, our rationale in this study is to evaluate the role of the parenchyma hydronephrosis area ratio (PHAR) in initial evaluation and follow up of UPJO patients in correlation to renal isotope studies. Objective To evaluate sonographic assessment of Renal Parenchyma to Hydronephrosis Area Ratio (PHAR) in the initial management and follow up of UPJO patients in correlation with the renal scan. Patients and Methods Site of the study: All patients were selected from the children who attended our outpatient department and have proven UPJO and meeting the criteria for the need of surgical intervention at Faculty of Medicine, Ain Shams University. Sample Size: 36 patients. Using PASS II Program for sample size calculation and according to (Rickard et al,2016), the expected AUC for PHAR prediction of future surgical intervention = 0.18, 30% rate of surgical intervention, setting power at 8% and error at 0.05, sample size of 36 patients will be needed. Results We enrolled 36 cases of children ≤ 16 years old (7.93 ± 0.83) with unilateral UPJO. Preoperative ultrasound parameters of the hydronephrotic kidneys [including degree of hydronephrosis, parenchymal thickness and PHAR] and renal isotope are measured &amp; compared with the same parameters after surgical repair of the UPJO (Anderson Hynes pyeloplasty) at 3rd months. After operation, 31 cases (86.1%) improved &amp; 5 cases not improved (13.9%). We find a significant change in all parameters at 3 months postoperatively (p &amp;lt; 0.01) as T ½ (25.22 ± 2.49 &amp; 17.57 ± 3.84) significantly decrease &amp; parenchymal thickness (9.42 ± 4.92 &amp; 15.12 ± 4.86), GFR of the affected kidney (34.31 ± 3.31 &amp; 48.32 ± 6.99) split renal function (37.30 ± 3.80 &amp; 44.03 ±4.11) and PHAR (0.86 ± 0.30 &amp; 2.45 ± 0.93) significantly increase post operatively. PHAR post operatively shows positive correlation with parenchymal thickness &amp; renal isotope while negative correlation with T ½. Conclusion PHAR is a promising parameter that can be estimated on presentation US to help predict the future need for surgery and follow up in children with ureteropelvic junction obstruction. Early identification of children who may require surgical intervention allows for closer surveillance of those patients as well as the opportunity for more selective ordering of invasive testing.

Correlation between ADC Values and Split Renal Function by Renal Isotope Scan in Assessment of Nephropathy

Background Early assessment of renal structure and function is crucial for the proper management and treatment of renal disease. DW-MRI show the Brownian motion of water molecules using the ADC values yielding information on water diffusion in the extracellular and extravascular space and capillary perfusion. Aim of the Work to study the ability of DWI in assessing and evaluating the individual renal function by correlating the ADC values calculated with split GFR obtained from dynamic renal scan among cases and healthy control group. Patients and Methods This prospective study was conducted on 30 patients and 30 control healthy group. Both MR examination and dynamic renal scan were performed on 30-case group, only MR examination was done on 30-healthy control group. DWI (b = 0, 200, 800 s/mm2) was done on 1.5T MRI unit. ADC map was calculated for every kidney. Split GFRs were measured from 99-Tcm DTPA scintigraphy. Results our study revealed that ADC values of normal control group is lower than that of case group. Cut off value of ADC, that discriminate between case and control group (using average ADC value of both kidneys), was ≤2.1 x10-3 mm2/s with Sensitivity = 87% and Specificity = 47%. We classified renal dysfunction, according to the total GFR measured from the dynamic renal scan and comparing it with the standard normalized GFR ranges according to age and sex in to 3 groups : suboptimal, decompensated and deteriorated renal dysfunction, the mean ADC values were 2.07 ± 0.21, 2.01 ± 0.13 and 1.45 ± 0.19 x10-3 mm2/s respectively. Conclusion There is a positive relationship between the ADC values and split GFR. DWI has a potential value for evaluating individual renal function, and may provide functional and morphological information at the same time.

QED corrections to parton distributions and Altarelli–Parisi splitting functions in the polarized case

We discuss the effect of QED corrections in the evolution of polarized parton distributions. We solve the corresponding evolution equations exactly to {mathcal {O}}(alpha ) and {mathcal {O}}(a_{textrm{S}}^2) in Mellin N-space, extending the available techniques for pure QCD evolution. To accomplish this, we introduce, for the first time, the Altarelli–Parisi polarized kernels at LO in QED. Furthermore, we perform a phenomenological analysis of the QED effects on polarized parton distributions (pPDFs), proposing different scenarios for the polarized photon density. Finally, we quantify the impact of the corresponding QED contributions to the polarized structure function g_1. We show that the relative corrections to both the pPDFs and the g_1 structure function are approximately at the few percent level, which is the order of magnitude expected considering the value of alpha .

18F]-PSMA-1007-PET for evaluation of kidney function.

Prostate-specific membrane antigen (PSMA) is present in the proximal tubule cells of the kidneys. This results in high renal tracer uptake in PSMA-PET, which may contain useful information on renal function. As part of the evaluation for [177Lu]-PSMA therapies, patients undergo PSMA-PET and additional [99mTc]-mercapto-acetyltriglycine (MAG3) scintigraphy to assess renal function. Aim of this study was to evaluate estimation of renal function with [18F]-PSMA-1007-PET/CT (PSMA-PET) by comparison to timely MAG3-scintigraphies. We retrospectively investigated 73 prostate cancer patients with 93 timely available PSMA-PET/CT, MAG3-scintigraphies and serum creatinine. For determination of split renal function in PSMA-PET/CT, we evaluated the relative unilateral total renal PSMA uptake, i.e. SUVmean multiplied by the renal volume (SRFPSMA-TOTAL) and relative unilateral maximal standardized uptake value (SRFSUV). These were compared to MAG3 split renal function (SRFMAG3) using Pearson correlation and receiver operating characteristics analysis. For determination of global renal function, correlation of bilateral total renal PSMA uptake with MAG3 tubular excretion rate and serum creatinine was assessed. SRFMAG3 was strongly correlated with SRFPSMA-TOTAL (r= 0.872, p<0.001) and with SRFSUV (r=0.815, p<0.001). Relevant abnormalities of SRFMAG3 (unilateral renal function < 25 %) could be detected with sensitivities and specificities of 90% and 92% for SRFPSMA-TOTAL, and 80% and 95% for SRFSUV. Measures of absolute renal function were only weakly correlated with bilateral total renal PSMA uptake. Renal [18F]-PSMA-1007 uptake allowed to quantify renal split function with good accuracy based on SRFPSMA-TOTAL or SRFSUV.